aboutsummaryrefslogtreecommitdiff
path: root/gdb/gdbserver/linux-low.c
blob: 22d8eb12cf196d784780b0d5dc7ee1a689971499 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
/* Low level interface to ptrace, for the remote server for GDB.
   Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
   2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "server.h"
#include "linux-low.h"

#include <sys/wait.h>
#include <stdio.h>
#include <sys/param.h>
#include <sys/ptrace.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/syscall.h>
#include <sched.h>
#include <ctype.h>
#include <pwd.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/vfs.h>
#include <sys/uio.h>
#ifndef ELFMAG0
/* Don't include <linux/elf.h> here.  If it got included by gdb_proc_service.h
   then ELFMAG0 will have been defined.  If it didn't get included by
   gdb_proc_service.h then including it will likely introduce a duplicate
   definition of elf_fpregset_t.  */
#include <elf.h>
#endif

#ifndef SPUFS_MAGIC
#define SPUFS_MAGIC 0x23c9b64e
#endif

#ifndef PTRACE_GETSIGINFO
# define PTRACE_GETSIGINFO 0x4202
# define PTRACE_SETSIGINFO 0x4203
#endif

#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif

/* If the system headers did not provide the constants, hard-code the normal
   values.  */
#ifndef PTRACE_EVENT_FORK

#define PTRACE_SETOPTIONS	0x4200
#define PTRACE_GETEVENTMSG	0x4201

/* options set using PTRACE_SETOPTIONS */
#define PTRACE_O_TRACESYSGOOD	0x00000001
#define PTRACE_O_TRACEFORK	0x00000002
#define PTRACE_O_TRACEVFORK	0x00000004
#define PTRACE_O_TRACECLONE	0x00000008
#define PTRACE_O_TRACEEXEC	0x00000010
#define PTRACE_O_TRACEVFORKDONE	0x00000020
#define PTRACE_O_TRACEEXIT	0x00000040

/* Wait extended result codes for the above trace options.  */
#define PTRACE_EVENT_FORK	1
#define PTRACE_EVENT_VFORK	2
#define PTRACE_EVENT_CLONE	3
#define PTRACE_EVENT_EXEC	4
#define PTRACE_EVENT_VFORK_DONE	5
#define PTRACE_EVENT_EXIT	6

#endif /* PTRACE_EVENT_FORK */

/* We can't always assume that this flag is available, but all systems
   with the ptrace event handlers also have __WALL, so it's safe to use
   in some contexts.  */
#ifndef __WALL
#define __WALL          0x40000000 /* Wait for any child.  */
#endif

#ifndef W_STOPCODE
#define W_STOPCODE(sig) ((sig) << 8 | 0x7f)
#endif

#ifdef __UCLIBC__
#if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__))
#define HAS_NOMMU
#endif
#endif

/* ``all_threads'' is keyed by the LWP ID, which we use as the GDB protocol
   representation of the thread ID.

   ``all_lwps'' is keyed by the process ID - which on Linux is (presently)
   the same as the LWP ID.

   ``all_processes'' is keyed by the "overall process ID", which
   GNU/Linux calls tgid, "thread group ID".  */

struct inferior_list all_lwps;

/* A list of all unknown processes which receive stop signals.  Some other
   process will presumably claim each of these as forked children
   momentarily.  */

struct inferior_list stopped_pids;

/* FIXME this is a bit of a hack, and could be removed.  */
int stopping_threads;

/* FIXME make into a target method?  */
int using_threads = 1;

/* True if we're presently stabilizing threads (moving them out of
   jump pads).  */
static int stabilizing_threads;

/* This flag is true iff we've just created or attached to our first
   inferior but it has not stopped yet.  As soon as it does, we need
   to call the low target's arch_setup callback.  Doing this only on
   the first inferior avoids reinializing the architecture on every
   inferior, and avoids messing with the register caches of the
   already running inferiors.  NOTE: this assumes all inferiors under
   control of gdbserver have the same architecture.  */
static int new_inferior;

static void linux_resume_one_lwp (struct lwp_info *lwp,
				  int step, int signal, siginfo_t *info);
static void linux_resume (struct thread_resume *resume_info, size_t n);
static void stop_all_lwps (int suspend, struct lwp_info *except);
static void unstop_all_lwps (int unsuspend, struct lwp_info *except);
static int linux_wait_for_event (ptid_t ptid, int *wstat, int options);
static void *add_lwp (ptid_t ptid);
static int linux_stopped_by_watchpoint (void);
static void mark_lwp_dead (struct lwp_info *lwp, int wstat);
static int linux_core_of_thread (ptid_t ptid);
static void proceed_all_lwps (void);
static int finish_step_over (struct lwp_info *lwp);
static CORE_ADDR get_stop_pc (struct lwp_info *lwp);
static int kill_lwp (unsigned long lwpid, int signo);
static void linux_enable_event_reporting (int pid);

/* True if the low target can hardware single-step.  Such targets
   don't need a BREAKPOINT_REINSERT_ADDR callback.  */

static int
can_hardware_single_step (void)
{
  return (the_low_target.breakpoint_reinsert_addr == NULL);
}

/* True if the low target supports memory breakpoints.  If so, we'll
   have a GET_PC implementation.  */

static int
supports_breakpoints (void)
{
  return (the_low_target.get_pc != NULL);
}

/* Returns true if this target can support fast tracepoints.  This
   does not mean that the in-process agent has been loaded in the
   inferior.  */

static int
supports_fast_tracepoints (void)
{
  return the_low_target.install_fast_tracepoint_jump_pad != NULL;
}

struct pending_signals
{
  int signal;
  siginfo_t info;
  struct pending_signals *prev;
};

#define PTRACE_ARG3_TYPE void *
#define PTRACE_ARG4_TYPE void *
#define PTRACE_XFER_TYPE long

#ifdef HAVE_LINUX_REGSETS
static char *disabled_regsets;
static int num_regsets;
#endif

/* The read/write ends of the pipe registered as waitable file in the
   event loop.  */
static int linux_event_pipe[2] = { -1, -1 };

/* True if we're currently in async mode.  */
#define target_is_async_p() (linux_event_pipe[0] != -1)

static void send_sigstop (struct lwp_info *lwp);
static void wait_for_sigstop (struct inferior_list_entry *entry);

/* Accepts an integer PID; Returns a string representing a file that
   can be opened to get info for the child process.
   Space for the result is malloc'd, caller must free.  */

char *
linux_child_pid_to_exec_file (int pid)
{
  char *name1, *name2;

  name1 = xmalloc (MAXPATHLEN);
  name2 = xmalloc (MAXPATHLEN);
  memset (name2, 0, MAXPATHLEN);

  sprintf (name1, "/proc/%d/exe", pid);
  if (readlink (name1, name2, MAXPATHLEN) > 0)
    {
      free (name1);
      return name2;
    }
  else
    {
      free (name2);
      return name1;
    }
}

/* Return non-zero if HEADER is a 64-bit ELF file.  */

static int
elf_64_header_p (const Elf64_Ehdr *header)
{
  return (header->e_ident[EI_MAG0] == ELFMAG0
          && header->e_ident[EI_MAG1] == ELFMAG1
          && header->e_ident[EI_MAG2] == ELFMAG2
          && header->e_ident[EI_MAG3] == ELFMAG3
          && header->e_ident[EI_CLASS] == ELFCLASS64);
}

/* Return non-zero if FILE is a 64-bit ELF file,
   zero if the file is not a 64-bit ELF file,
   and -1 if the file is not accessible or doesn't exist.  */

int
elf_64_file_p (const char *file)
{
  Elf64_Ehdr header;
  int fd;

  fd = open (file, O_RDONLY);
  if (fd < 0)
    return -1;

  if (read (fd, &header, sizeof (header)) != sizeof (header))
    {
      close (fd);
      return 0;
    }
  close (fd);

  return elf_64_header_p (&header);
}

static void
delete_lwp (struct lwp_info *lwp)
{
  remove_thread (get_lwp_thread (lwp));
  remove_inferior (&all_lwps, &lwp->head);
  free (lwp->arch_private);
  free (lwp);
}

/* Add a process to the common process list, and set its private
   data.  */

static struct process_info *
linux_add_process (int pid, int attached)
{
  struct process_info *proc;

  /* Is this the first process?  If so, then set the arch.  */
  if (all_processes.head == NULL)
    new_inferior = 1;

  proc = add_process (pid, attached);
  proc->private = xcalloc (1, sizeof (*proc->private));

  if (the_low_target.new_process != NULL)
    proc->private->arch_private = the_low_target.new_process ();

  return proc;
}

/* Wrapper function for waitpid which handles EINTR, and emulates
   __WALL for systems where that is not available.  */

static int
my_waitpid (int pid, int *status, int flags)
{
  int ret, out_errno;

  if (debug_threads)
    fprintf (stderr, "my_waitpid (%d, 0x%x)\n", pid, flags);

  if (flags & __WALL)
    {
      sigset_t block_mask, org_mask, wake_mask;
      int wnohang;

      wnohang = (flags & WNOHANG) != 0;
      flags &= ~(__WALL | __WCLONE);
      flags |= WNOHANG;

      /* Block all signals while here.  This avoids knowing about
	 LinuxThread's signals.  */
      sigfillset (&block_mask);
      sigprocmask (SIG_BLOCK, &block_mask, &org_mask);

      /* ... except during the sigsuspend below.  */
      sigemptyset (&wake_mask);

      while (1)
	{
	  /* Since all signals are blocked, there's no need to check
	     for EINTR here.  */
	  ret = waitpid (pid, status, flags);
	  out_errno = errno;

	  if (ret == -1 && out_errno != ECHILD)
	    break;
	  else if (ret > 0)
	    break;

	  if (flags & __WCLONE)
	    {
	      /* We've tried both flavors now.  If WNOHANG is set,
		 there's nothing else to do, just bail out.  */
	      if (wnohang)
		break;

	      if (debug_threads)
		fprintf (stderr, "blocking\n");

	      /* Block waiting for signals.  */
	      sigsuspend (&wake_mask);
	    }

	  flags ^= __WCLONE;
	}

      sigprocmask (SIG_SETMASK, &org_mask, NULL);
    }
  else
    {
      do
	ret = waitpid (pid, status, flags);
      while (ret == -1 && errno == EINTR);
      out_errno = errno;
    }

  if (debug_threads)
    fprintf (stderr, "my_waitpid (%d, 0x%x): status(%x), %d\n",
	     pid, flags, status ? *status : -1, ret);

  errno = out_errno;
  return ret;
}

/* Handle a GNU/Linux extended wait response.  If we see a clone
   event, we need to add the new LWP to our list (and not report the
   trap to higher layers).  */

static void
handle_extended_wait (struct lwp_info *event_child, int wstat)
{
  int event = wstat >> 16;
  struct lwp_info *new_lwp;

  if (event == PTRACE_EVENT_CLONE)
    {
      ptid_t ptid;
      unsigned long new_pid;
      int ret, status = W_STOPCODE (SIGSTOP);

      ptrace (PTRACE_GETEVENTMSG, lwpid_of (event_child), 0, &new_pid);

      /* If we haven't already seen the new PID stop, wait for it now.  */
      if (! pull_pid_from_list (&stopped_pids, new_pid))
	{
	  /* The new child has a pending SIGSTOP.  We can't affect it until it
	     hits the SIGSTOP, but we're already attached.  */

	  ret = my_waitpid (new_pid, &status, __WALL);

	  if (ret == -1)
	    perror_with_name ("waiting for new child");
	  else if (ret != new_pid)
	    warning ("wait returned unexpected PID %d", ret);
	  else if (!WIFSTOPPED (status))
	    warning ("wait returned unexpected status 0x%x", status);
	}

      linux_enable_event_reporting (new_pid);

      ptid = ptid_build (pid_of (event_child), new_pid, 0);
      new_lwp = (struct lwp_info *) add_lwp (ptid);
      add_thread (ptid, new_lwp);

      /* Either we're going to immediately resume the new thread
	 or leave it stopped.  linux_resume_one_lwp is a nop if it
	 thinks the thread is currently running, so set this first
	 before calling linux_resume_one_lwp.  */
      new_lwp->stopped = 1;

      /* Normally we will get the pending SIGSTOP.  But in some cases
	 we might get another signal delivered to the group first.
	 If we do get another signal, be sure not to lose it.  */
      if (WSTOPSIG (status) == SIGSTOP)
	{
	  if (stopping_threads)
	    new_lwp->stop_pc = get_stop_pc (new_lwp);
	  else
	    linux_resume_one_lwp (new_lwp, 0, 0, NULL);
	}
      else
	{
	  new_lwp->stop_expected = 1;

	  if (stopping_threads)
	    {
	      new_lwp->stop_pc = get_stop_pc (new_lwp);
	      new_lwp->status_pending_p = 1;
	      new_lwp->status_pending = status;
	    }
	  else
	    /* Pass the signal on.  This is what GDB does - except
	       shouldn't we really report it instead?  */
	    linux_resume_one_lwp (new_lwp, 0, WSTOPSIG (status), NULL);
	}

      /* Always resume the current thread.  If we are stopping
	 threads, it will have a pending SIGSTOP; we may as well
	 collect it now.  */
      linux_resume_one_lwp (event_child, event_child->stepping, 0, NULL);
    }
}

/* Return the PC as read from the regcache of LWP, without any
   adjustment.  */

static CORE_ADDR
get_pc (struct lwp_info *lwp)
{
  struct thread_info *saved_inferior;
  struct regcache *regcache;
  CORE_ADDR pc;

  if (the_low_target.get_pc == NULL)
    return 0;

  saved_inferior = current_inferior;
  current_inferior = get_lwp_thread (lwp);

  regcache = get_thread_regcache (current_inferior, 1);
  pc = (*the_low_target.get_pc) (regcache);

  if (debug_threads)
    fprintf (stderr, "pc is 0x%lx\n", (long) pc);

  current_inferior = saved_inferior;
  return pc;
}

/* This function should only be called if LWP got a SIGTRAP.
   The SIGTRAP could mean several things.

   On i386, where decr_pc_after_break is non-zero:
   If we were single-stepping this process using PTRACE_SINGLESTEP,
   we will get only the one SIGTRAP (even if the instruction we
   stepped over was a breakpoint).  The value of $eip will be the
   next instruction.
   If we continue the process using PTRACE_CONT, we will get a
   SIGTRAP when we hit a breakpoint.  The value of $eip will be
   the instruction after the breakpoint (i.e. needs to be
   decremented).  If we report the SIGTRAP to GDB, we must also
   report the undecremented PC.  If we cancel the SIGTRAP, we
   must resume at the decremented PC.

   (Presumably, not yet tested) On a non-decr_pc_after_break machine
   with hardware or kernel single-step:
   If we single-step over a breakpoint instruction, our PC will
   point at the following instruction.  If we continue and hit a
   breakpoint instruction, our PC will point at the breakpoint
   instruction.  */

static CORE_ADDR
get_stop_pc (struct lwp_info *lwp)
{
  CORE_ADDR stop_pc;

  if (the_low_target.get_pc == NULL)
    return 0;

  stop_pc = get_pc (lwp);

  if (WSTOPSIG (lwp->last_status) == SIGTRAP
      && !lwp->stepping
      && !lwp->stopped_by_watchpoint
      && lwp->last_status >> 16 == 0)
    stop_pc -= the_low_target.decr_pc_after_break;

  if (debug_threads)
    fprintf (stderr, "stop pc is 0x%lx\n", (long) stop_pc);

  return stop_pc;
}

static void *
add_lwp (ptid_t ptid)
{
  struct lwp_info *lwp;

  lwp = (struct lwp_info *) xmalloc (sizeof (*lwp));
  memset (lwp, 0, sizeof (*lwp));

  lwp->head.id = ptid;

  if (the_low_target.new_thread != NULL)
    lwp->arch_private = the_low_target.new_thread ();

  add_inferior_to_list (&all_lwps, &lwp->head);

  return lwp;
}

/* Start an inferior process and returns its pid.
   ALLARGS is a vector of program-name and args. */

static int
linux_create_inferior (char *program, char **allargs)
{
  struct lwp_info *new_lwp;
  int pid;
  ptid_t ptid;

#if defined(__UCLIBC__) && defined(HAS_NOMMU)
  pid = vfork ();
#else
  pid = fork ();
#endif
  if (pid < 0)
    perror_with_name ("fork");

  if (pid == 0)
    {
      ptrace (PTRACE_TRACEME, 0, 0, 0);

#ifdef __SIGRTMIN /* Bionic doesn't use SIGRTMIN the way glibc does.  */
      signal (__SIGRTMIN + 1, SIG_DFL);
#endif

      setpgid (0, 0);

      execv (program, allargs);
      if (errno == ENOENT)
	execvp (program, allargs);

      fprintf (stderr, "Cannot exec %s: %s.\n", program,
	       strerror (errno));
      fflush (stderr);
      _exit (0177);
    }

  linux_add_process (pid, 0);

  ptid = ptid_build (pid, pid, 0);
  new_lwp = add_lwp (ptid);
  add_thread (ptid, new_lwp);
  new_lwp->must_set_ptrace_flags = 1;

  return pid;
}

/* Attach to an inferior process.  */

static void
linux_attach_lwp_1 (unsigned long lwpid, int initial)
{
  ptid_t ptid;
  struct lwp_info *new_lwp;

  if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) != 0)
    {
      if (!initial)
	{
	  /* If we fail to attach to an LWP, just warn.  */
	  fprintf (stderr, "Cannot attach to lwp %ld: %s (%d)\n", lwpid,
		   strerror (errno), errno);
	  fflush (stderr);
	  return;
	}
      else
	/* If we fail to attach to a process, report an error.  */
	error ("Cannot attach to lwp %ld: %s (%d)\n", lwpid,
	       strerror (errno), errno);
    }

  if (initial)
    /* NOTE/FIXME: This lwp might have not been the tgid.  */
    ptid = ptid_build (lwpid, lwpid, 0);
  else
    {
      /* Note that extracting the pid from the current inferior is
	 safe, since we're always called in the context of the same
	 process as this new thread.  */
      int pid = pid_of (get_thread_lwp (current_inferior));
      ptid = ptid_build (pid, lwpid, 0);
    }

  new_lwp = (struct lwp_info *) add_lwp (ptid);
  add_thread (ptid, new_lwp);

  /* We need to wait for SIGSTOP before being able to make the next
     ptrace call on this LWP.  */
  new_lwp->must_set_ptrace_flags = 1;

  /* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH
     brings it to a halt.

     There are several cases to consider here:

     1) gdbserver has already attached to the process and is being notified
	of a new thread that is being created.
	In this case we should ignore that SIGSTOP and resume the
	process.  This is handled below by setting stop_expected = 1,
	and the fact that add_thread sets last_resume_kind ==
	resume_continue.

     2) This is the first thread (the process thread), and we're attaching
	to it via attach_inferior.
	In this case we want the process thread to stop.
	This is handled by having linux_attach set last_resume_kind ==
	resume_stop after we return.
	??? If the process already has several threads we leave the other
	threads running.

     3) GDB is connecting to gdbserver and is requesting an enumeration of all
	existing threads.
	In this case we want the thread to stop.
	FIXME: This case is currently not properly handled.
	We should wait for the SIGSTOP but don't.  Things work apparently
	because enough time passes between when we ptrace (ATTACH) and when
	gdb makes the next ptrace call on the thread.

     On the other hand, if we are currently trying to stop all threads, we
     should treat the new thread as if we had sent it a SIGSTOP.  This works
     because we are guaranteed that the add_lwp call above added us to the
     end of the list, and so the new thread has not yet reached
     wait_for_sigstop (but will).  */
  new_lwp->stop_expected = 1;
}

void
linux_attach_lwp (unsigned long lwpid)
{
  linux_attach_lwp_1 (lwpid, 0);
}

int
linux_attach (unsigned long pid)
{
  linux_attach_lwp_1 (pid, 1);
  linux_add_process (pid, 1);

  if (!non_stop)
    {
      struct thread_info *thread;

     /* Don't ignore the initial SIGSTOP if we just attached to this
	process.  It will be collected by wait shortly.  */
      thread = find_thread_ptid (ptid_build (pid, pid, 0));
      thread->last_resume_kind = resume_stop;
    }

  return 0;
}

struct counter
{
  int pid;
  int count;
};

static int
second_thread_of_pid_p (struct inferior_list_entry *entry, void *args)
{
  struct counter *counter = args;

  if (ptid_get_pid (entry->id) == counter->pid)
    {
      if (++counter->count > 1)
	return 1;
    }

  return 0;
}

static int
last_thread_of_process_p (struct thread_info *thread)
{
  ptid_t ptid = ((struct inferior_list_entry *)thread)->id;
  int pid = ptid_get_pid (ptid);
  struct counter counter = { pid , 0 };

  return (find_inferior (&all_threads,
			 second_thread_of_pid_p, &counter) == NULL);
}

/* Kill the inferior lwp.  */

static int
linux_kill_one_lwp (struct inferior_list_entry *entry, void *args)
{
  struct thread_info *thread = (struct thread_info *) entry;
  struct lwp_info *lwp = get_thread_lwp (thread);
  int wstat;
  int pid = * (int *) args;

  if (ptid_get_pid (entry->id) != pid)
    return 0;

  /* We avoid killing the first thread here, because of a Linux kernel (at
     least 2.6.0-test7 through 2.6.8-rc4) bug; if we kill the parent before
     the children get a chance to be reaped, it will remain a zombie
     forever.  */

  if (lwpid_of (lwp) == pid)
    {
      if (debug_threads)
	fprintf (stderr, "lkop: is last of process %s\n",
		 target_pid_to_str (entry->id));
      return 0;
    }

  do
    {
      ptrace (PTRACE_KILL, lwpid_of (lwp), 0, 0);

      /* Make sure it died.  The loop is most likely unnecessary.  */
      pid = linux_wait_for_event (lwp->head.id, &wstat, __WALL);
    } while (pid > 0 && WIFSTOPPED (wstat));

  return 0;
}

static int
linux_kill (int pid)
{
  struct process_info *process;
  struct lwp_info *lwp;
  struct thread_info *thread;
  int wstat;
  int lwpid;

  process = find_process_pid (pid);
  if (process == NULL)
    return -1;

  /* If we're killing a running inferior, make sure it is stopped
     first, as PTRACE_KILL will not work otherwise.  */
  stop_all_lwps (0, NULL);

  find_inferior (&all_threads, linux_kill_one_lwp, &pid);

  /* See the comment in linux_kill_one_lwp.  We did not kill the first
     thread in the list, so do so now.  */
  lwp = find_lwp_pid (pid_to_ptid (pid));
  thread = get_lwp_thread (lwp);

  if (debug_threads)
    fprintf (stderr, "lk_1: killing lwp %ld, for pid: %d\n",
	     lwpid_of (lwp), pid);

  do
    {
      ptrace (PTRACE_KILL, lwpid_of (lwp), 0, 0);

      /* Make sure it died.  The loop is most likely unnecessary.  */
      lwpid = linux_wait_for_event (lwp->head.id, &wstat, __WALL);
    } while (lwpid > 0 && WIFSTOPPED (wstat));

  the_target->mourn (process);

  /* Since we presently can only stop all lwps of all processes, we
     need to unstop lwps of other processes.  */
  unstop_all_lwps (0, NULL);
  return 0;
}

static int
linux_detach_one_lwp (struct inferior_list_entry *entry, void *args)
{
  struct thread_info *thread = (struct thread_info *) entry;
  struct lwp_info *lwp = get_thread_lwp (thread);
  int pid = * (int *) args;

  if (ptid_get_pid (entry->id) != pid)
    return 0;

  /* If this process is stopped but is expecting a SIGSTOP, then make
     sure we take care of that now.  This isn't absolutely guaranteed
     to collect the SIGSTOP, but is fairly likely to.  */
  if (lwp->stop_expected)
    {
      int wstat;
      /* Clear stop_expected, so that the SIGSTOP will be reported.  */
      lwp->stop_expected = 0;
      linux_resume_one_lwp (lwp, 0, 0, NULL);
      linux_wait_for_event (lwp->head.id, &wstat, __WALL);
    }

  /* Flush any pending changes to the process's registers.  */
  regcache_invalidate_one ((struct inferior_list_entry *)
			   get_lwp_thread (lwp));

  /* Finally, let it resume.  */
  ptrace (PTRACE_DETACH, lwpid_of (lwp), 0, 0);

  delete_lwp (lwp);
  return 0;
}

static int
linux_detach (int pid)
{
  struct process_info *process;

  process = find_process_pid (pid);
  if (process == NULL)
    return -1;

  /* Stop all threads before detaching.  First, ptrace requires that
     the thread is stopped to sucessfully detach.  Second, thread_db
     may need to uninstall thread event breakpoints from memory, which
     only works with a stopped process anyway.  */
  stop_all_lwps (0, NULL);

#ifdef USE_THREAD_DB
  thread_db_detach (process);
#endif

  /* Stabilize threads (move out of jump pads).  */
  stabilize_threads ();

  find_inferior (&all_threads, linux_detach_one_lwp, &pid);

  the_target->mourn (process);

  /* Since we presently can only stop all lwps of all processes, we
     need to unstop lwps of other processes.  */
  unstop_all_lwps (0, NULL);
  return 0;
}

/* Remove all LWPs that belong to process PROC from the lwp list.  */

static int
delete_lwp_callback (struct inferior_list_entry *entry, void *proc)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;
  struct process_info *process = proc;

  if (pid_of (lwp) == pid_of (process))
    delete_lwp (lwp);

  return 0;
}

static void
linux_mourn (struct process_info *process)
{
  struct process_info_private *priv;

#ifdef USE_THREAD_DB
  thread_db_mourn (process);
#endif

  find_inferior (&all_lwps, delete_lwp_callback, process);

  /* Freeing all private data.  */
  priv = process->private;
  free (priv->arch_private);
  free (priv);
  process->private = NULL;

  remove_process (process);
}

static void
linux_join (int pid)
{
  int status, ret;
  struct process_info *process;

  process = find_process_pid (pid);
  if (process == NULL)
    return;

  do {
    ret = my_waitpid (pid, &status, 0);
    if (WIFEXITED (status) || WIFSIGNALED (status))
      break;
  } while (ret != -1 || errno != ECHILD);
}

/* Return nonzero if the given thread is still alive.  */
static int
linux_thread_alive (ptid_t ptid)
{
  struct lwp_info *lwp = find_lwp_pid (ptid);

  /* We assume we always know if a thread exits.  If a whole process
     exited but we still haven't been able to report it to GDB, we'll
     hold on to the last lwp of the dead process.  */
  if (lwp != NULL)
    return !lwp->dead;
  else
    return 0;
}

/* Return 1 if this lwp has an interesting status pending.  */
static int
status_pending_p_callback (struct inferior_list_entry *entry, void *arg)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;
  ptid_t ptid = * (ptid_t *) arg;
  struct thread_info *thread;

  /* Check if we're only interested in events from a specific process
     or its lwps.  */
  if (!ptid_equal (minus_one_ptid, ptid)
      && ptid_get_pid (ptid) != ptid_get_pid (lwp->head.id))
    return 0;

  thread = get_lwp_thread (lwp);

  /* If we got a `vCont;t', but we haven't reported a stop yet, do
     report any status pending the LWP may have.  */
  if (thread->last_resume_kind == resume_stop
      && thread->last_status.kind != TARGET_WAITKIND_IGNORE)
    return 0;

  return lwp->status_pending_p;
}

static int
same_lwp (struct inferior_list_entry *entry, void *data)
{
  ptid_t ptid = *(ptid_t *) data;
  int lwp;

  if (ptid_get_lwp (ptid) != 0)
    lwp = ptid_get_lwp (ptid);
  else
    lwp = ptid_get_pid (ptid);

  if (ptid_get_lwp (entry->id) == lwp)
    return 1;

  return 0;
}

struct lwp_info *
find_lwp_pid (ptid_t ptid)
{
  return (struct lwp_info*) find_inferior (&all_lwps, same_lwp, &ptid);
}

static struct lwp_info *
linux_wait_for_lwp (ptid_t ptid, int *wstatp, int options)
{
  int ret;
  int to_wait_for = -1;
  struct lwp_info *child = NULL;

  if (debug_threads)
    fprintf (stderr, "linux_wait_for_lwp: %s\n", target_pid_to_str (ptid));

  if (ptid_equal (ptid, minus_one_ptid))
    to_wait_for = -1;			/* any child */
  else
    to_wait_for = ptid_get_lwp (ptid);	/* this lwp only */

  options |= __WALL;

retry:

  ret = my_waitpid (to_wait_for, wstatp, options);
  if (ret == 0 || (ret == -1 && errno == ECHILD && (options & WNOHANG)))
    return NULL;
  else if (ret == -1)
    perror_with_name ("waitpid");

  if (debug_threads
      && (!WIFSTOPPED (*wstatp)
	  || (WSTOPSIG (*wstatp) != 32
	      && WSTOPSIG (*wstatp) != 33)))
    fprintf (stderr, "Got an event from %d (%x)\n", ret, *wstatp);

  child = find_lwp_pid (pid_to_ptid (ret));

  /* If we didn't find a process, one of two things presumably happened:
     - A process we started and then detached from has exited.  Ignore it.
     - A process we are controlling has forked and the new child's stop
     was reported to us by the kernel.  Save its PID.  */
  if (child == NULL && WIFSTOPPED (*wstatp))
    {
      add_pid_to_list (&stopped_pids, ret);
      goto retry;
    }
  else if (child == NULL)
    goto retry;

  child->stopped = 1;

  child->last_status = *wstatp;

  /* Architecture-specific setup after inferior is running.
     This needs to happen after we have attached to the inferior
     and it is stopped for the first time, but before we access
     any inferior registers.  */
  if (new_inferior)
    {
      the_low_target.arch_setup ();
#ifdef HAVE_LINUX_REGSETS
      memset (disabled_regsets, 0, num_regsets);
#endif
      new_inferior = 0;
    }

  /* Fetch the possibly triggered data watchpoint info and store it in
     CHILD.

     On some archs, like x86, that use debug registers to set
     watchpoints, it's possible that the way to know which watched
     address trapped, is to check the register that is used to select
     which address to watch.  Problem is, between setting the
     watchpoint and reading back which data address trapped, the user
     may change the set of watchpoints, and, as a consequence, GDB
     changes the debug registers in the inferior.  To avoid reading
     back a stale stopped-data-address when that happens, we cache in
     LP the fact that a watchpoint trapped, and the corresponding data
     address, as soon as we see CHILD stop with a SIGTRAP.  If GDB
     changes the debug registers meanwhile, we have the cached data we
     can rely on.  */

  if (WIFSTOPPED (*wstatp) && WSTOPSIG (*wstatp) == SIGTRAP)
    {
      if (the_low_target.stopped_by_watchpoint == NULL)
	{
	  child->stopped_by_watchpoint = 0;
	}
      else
	{
	  struct thread_info *saved_inferior;

	  saved_inferior = current_inferior;
	  current_inferior = get_lwp_thread (child);

	  child->stopped_by_watchpoint
	    = the_low_target.stopped_by_watchpoint ();

	  if (child->stopped_by_watchpoint)
	    {
	      if (the_low_target.stopped_data_address != NULL)
		child->stopped_data_address
		  = the_low_target.stopped_data_address ();
	      else
		child->stopped_data_address = 0;
	    }

	  current_inferior = saved_inferior;
	}
    }

  /* Store the STOP_PC, with adjustment applied.  This depends on the
     architecture being defined already (so that CHILD has a valid
     regcache), and on LAST_STATUS being set (to check for SIGTRAP or
     not).  */
  if (WIFSTOPPED (*wstatp))
    child->stop_pc = get_stop_pc (child);

  if (debug_threads
      && WIFSTOPPED (*wstatp)
      && the_low_target.get_pc != NULL)
    {
      struct thread_info *saved_inferior = current_inferior;
      struct regcache *regcache;
      CORE_ADDR pc;

      current_inferior = get_lwp_thread (child);
      regcache = get_thread_regcache (current_inferior, 1);
      pc = (*the_low_target.get_pc) (regcache);
      fprintf (stderr, "linux_wait_for_lwp: pc is 0x%lx\n", (long) pc);
      current_inferior = saved_inferior;
    }

  return child;
}

/* This function should only be called if the LWP got a SIGTRAP.

   Handle any tracepoint steps or hits.  Return true if a tracepoint
   event was handled, 0 otherwise.  */

static int
handle_tracepoints (struct lwp_info *lwp)
{
  struct thread_info *tinfo = get_lwp_thread (lwp);
  int tpoint_related_event = 0;

  /* If this tracepoint hit causes a tracing stop, we'll immediately
     uninsert tracepoints.  To do this, we temporarily pause all
     threads, unpatch away, and then unpause threads.  We need to make
     sure the unpausing doesn't resume LWP too.  */
  lwp->suspended++;

  /* And we need to be sure that any all-threads-stopping doesn't try
     to move threads out of the jump pads, as it could deadlock the
     inferior (LWP could be in the jump pad, maybe even holding the
     lock.)  */

  /* Do any necessary step collect actions.  */
  tpoint_related_event |= tracepoint_finished_step (tinfo, lwp->stop_pc);

  tpoint_related_event |= handle_tracepoint_bkpts (tinfo, lwp->stop_pc);

  /* See if we just hit a tracepoint and do its main collect
     actions.  */
  tpoint_related_event |= tracepoint_was_hit (tinfo, lwp->stop_pc);

  lwp->suspended--;

  gdb_assert (lwp->suspended == 0);
  gdb_assert (!stabilizing_threads || lwp->collecting_fast_tracepoint);

  if (tpoint_related_event)
    {
      if (debug_threads)
	fprintf (stderr, "got a tracepoint event\n");
      return 1;
    }

  return 0;
}

/* Convenience wrapper.  Returns true if LWP is presently collecting a
   fast tracepoint.  */

static int
linux_fast_tracepoint_collecting (struct lwp_info *lwp,
				  struct fast_tpoint_collect_status *status)
{
  CORE_ADDR thread_area;

  if (the_low_target.get_thread_area == NULL)
    return 0;

  /* Get the thread area address.  This is used to recognize which
     thread is which when tracing with the in-process agent library.
     We don't read anything from the address, and treat it as opaque;
     it's the address itself that we assume is unique per-thread.  */
  if ((*the_low_target.get_thread_area) (lwpid_of (lwp), &thread_area) == -1)
    return 0;

  return fast_tracepoint_collecting (thread_area, lwp->stop_pc, status);
}

/* The reason we resume in the caller, is because we want to be able
   to pass lwp->status_pending as WSTAT, and we need to clear
   status_pending_p before resuming, otherwise, linux_resume_one_lwp
   refuses to resume.  */

static int
maybe_move_out_of_jump_pad (struct lwp_info *lwp, int *wstat)
{
  struct thread_info *saved_inferior;

  saved_inferior = current_inferior;
  current_inferior = get_lwp_thread (lwp);

  if ((wstat == NULL
       || (WIFSTOPPED (*wstat) && WSTOPSIG (*wstat) != SIGTRAP))
      && supports_fast_tracepoints ()
      && in_process_agent_loaded ())
    {
      struct fast_tpoint_collect_status status;
      int r;

      if (debug_threads)
	fprintf (stderr, "\
Checking whether LWP %ld needs to move out of the jump pad.\n",
		 lwpid_of (lwp));

      r = linux_fast_tracepoint_collecting (lwp, &status);

      if (wstat == NULL
	  || (WSTOPSIG (*wstat) != SIGILL
	      && WSTOPSIG (*wstat) != SIGFPE
	      && WSTOPSIG (*wstat) != SIGSEGV
	      && WSTOPSIG (*wstat) != SIGBUS))
	{
	  lwp->collecting_fast_tracepoint = r;

	  if (r != 0)
	    {
	      if (r == 1 && lwp->exit_jump_pad_bkpt == NULL)
		{
		  /* Haven't executed the original instruction yet.
		     Set breakpoint there, and wait till it's hit,
		     then single-step until exiting the jump pad.  */
		  lwp->exit_jump_pad_bkpt
		    = set_breakpoint_at (status.adjusted_insn_addr, NULL);
		}

	      if (debug_threads)
		fprintf (stderr, "\
Checking whether LWP %ld needs to move out of the jump pad...it does\n",
		 lwpid_of (lwp));

	      return 1;
	    }
	}
      else
	{
	  /* If we get a synchronous signal while collecting, *and*
	     while executing the (relocated) original instruction,
	     reset the PC to point at the tpoint address, before
	     reporting to GDB.  Otherwise, it's an IPA lib bug: just
	     report the signal to GDB, and pray for the best.  */

	  lwp->collecting_fast_tracepoint = 0;

	  if (r != 0
	      && (status.adjusted_insn_addr <= lwp->stop_pc
		  && lwp->stop_pc < status.adjusted_insn_addr_end))
	    {
	      siginfo_t info;
	      struct regcache *regcache;

	      /* The si_addr on a few signals references the address
		 of the faulting instruction.  Adjust that as
		 well.  */
	      if ((WSTOPSIG (*wstat) == SIGILL
		   || WSTOPSIG (*wstat) == SIGFPE
		   || WSTOPSIG (*wstat) == SIGBUS
		   || WSTOPSIG (*wstat) == SIGSEGV)
		  && ptrace (PTRACE_GETSIGINFO, lwpid_of (lwp), 0, &info) == 0
		  /* Final check just to make sure we don't clobber
		     the siginfo of non-kernel-sent signals.  */
		  && (uintptr_t) info.si_addr == lwp->stop_pc)
		{
		  info.si_addr = (void *) (uintptr_t) status.tpoint_addr;
		  ptrace (PTRACE_SETSIGINFO, lwpid_of (lwp), 0, &info);
		}

	      regcache = get_thread_regcache (get_lwp_thread (lwp), 1);
	      (*the_low_target.set_pc) (regcache, status.tpoint_addr);
	      lwp->stop_pc = status.tpoint_addr;

	      /* Cancel any fast tracepoint lock this thread was
		 holding.  */
	      force_unlock_trace_buffer ();
	    }

	  if (lwp->exit_jump_pad_bkpt != NULL)
	    {
	      if (debug_threads)
		fprintf (stderr,
			 "Cancelling fast exit-jump-pad: removing bkpt. "
			 "stopping all threads momentarily.\n");

	      stop_all_lwps (1, lwp);
	      cancel_breakpoints ();

	      delete_breakpoint (lwp->exit_jump_pad_bkpt);
	      lwp->exit_jump_pad_bkpt = NULL;

	      unstop_all_lwps (1, lwp);

	      gdb_assert (lwp->suspended >= 0);
	    }
	}
    }

  if (debug_threads)
    fprintf (stderr, "\
Checking whether LWP %ld needs to move out of the jump pad...no\n",
	     lwpid_of (lwp));
  return 0;
}

/* Enqueue one signal in the "signals to report later when out of the
   jump pad" list.  */

static void
enqueue_one_deferred_signal (struct lwp_info *lwp, int *wstat)
{
  struct pending_signals *p_sig;

  if (debug_threads)
    fprintf (stderr, "\
Deferring signal %d for LWP %ld.\n", WSTOPSIG (*wstat), lwpid_of (lwp));

  if (debug_threads)
    {
      struct pending_signals *sig;

      for (sig = lwp->pending_signals_to_report;
	   sig != NULL;
	   sig = sig->prev)
	fprintf (stderr,
		 "   Already queued %d\n",
		 sig->signal);

      fprintf (stderr, "   (no more currently queued signals)\n");
    }

  p_sig = xmalloc (sizeof (*p_sig));
  p_sig->prev = lwp->pending_signals_to_report;
  p_sig->signal = WSTOPSIG (*wstat);
  memset (&p_sig->info, 0, sizeof (siginfo_t));
  ptrace (PTRACE_GETSIGINFO, lwpid_of (lwp), 0, &p_sig->info);

  lwp->pending_signals_to_report = p_sig;
}

/* Dequeue one signal from the "signals to report later when out of
   the jump pad" list.  */

static int
dequeue_one_deferred_signal (struct lwp_info *lwp, int *wstat)
{
  if (lwp->pending_signals_to_report != NULL)
    {
      struct pending_signals **p_sig;

      p_sig = &lwp->pending_signals_to_report;
      while ((*p_sig)->prev != NULL)
	p_sig = &(*p_sig)->prev;

      *wstat = W_STOPCODE ((*p_sig)->signal);
      if ((*p_sig)->info.si_signo != 0)
	ptrace (PTRACE_SETSIGINFO, lwpid_of (lwp), 0, &(*p_sig)->info);
      free (*p_sig);
      *p_sig = NULL;

      if (debug_threads)
	fprintf (stderr, "Reporting deferred signal %d for LWP %ld.\n",
		 WSTOPSIG (*wstat), lwpid_of (lwp));

      if (debug_threads)
	{
	  struct pending_signals *sig;

	  for (sig = lwp->pending_signals_to_report;
	       sig != NULL;
	       sig = sig->prev)
	    fprintf (stderr,
		     "   Still queued %d\n",
		     sig->signal);

	  fprintf (stderr, "   (no more queued signals)\n");
	}

      return 1;
    }

  return 0;
}

/* Arrange for a breakpoint to be hit again later.  We don't keep the
   SIGTRAP status and don't forward the SIGTRAP signal to the LWP.  We
   will handle the current event, eventually we will resume this LWP,
   and this breakpoint will trap again.  */

static int
cancel_breakpoint (struct lwp_info *lwp)
{
  struct thread_info *saved_inferior;

  /* There's nothing to do if we don't support breakpoints.  */
  if (!supports_breakpoints ())
    return 0;

  /* breakpoint_at reads from current inferior.  */
  saved_inferior = current_inferior;
  current_inferior = get_lwp_thread (lwp);

  if ((*the_low_target.breakpoint_at) (lwp->stop_pc))
    {
      if (debug_threads)
	fprintf (stderr,
		 "CB: Push back breakpoint for %s\n",
		 target_pid_to_str (ptid_of (lwp)));

      /* Back up the PC if necessary.  */
      if (the_low_target.decr_pc_after_break)
	{
	  struct regcache *regcache
	    = get_thread_regcache (current_inferior, 1);
	  (*the_low_target.set_pc) (regcache, lwp->stop_pc);
	}

      current_inferior = saved_inferior;
      return 1;
    }
  else
    {
      if (debug_threads)
	fprintf (stderr,
		 "CB: No breakpoint found at %s for [%s]\n",
		 paddress (lwp->stop_pc),
		 target_pid_to_str (ptid_of (lwp)));
    }

  current_inferior = saved_inferior;
  return 0;
}

/* When the event-loop is doing a step-over, this points at the thread
   being stepped.  */
ptid_t step_over_bkpt;

/* Wait for an event from child PID.  If PID is -1, wait for any
   child.  Store the stop status through the status pointer WSTAT.
   OPTIONS is passed to the waitpid call.  Return 0 if no child stop
   event was found and OPTIONS contains WNOHANG.  Return the PID of
   the stopped child otherwise.  */

static int
linux_wait_for_event_1 (ptid_t ptid, int *wstat, int options)
{
  struct lwp_info *event_child, *requested_child;

  event_child = NULL;
  requested_child = NULL;

  /* Check for a lwp with a pending status.  */

  if (ptid_equal (ptid, minus_one_ptid)
      || ptid_equal (pid_to_ptid (ptid_get_pid (ptid)), ptid))
    {
      event_child = (struct lwp_info *)
	find_inferior (&all_lwps, status_pending_p_callback, &ptid);
      if (debug_threads && event_child)
	fprintf (stderr, "Got a pending child %ld\n", lwpid_of (event_child));
    }
  else
    {
      requested_child = find_lwp_pid (ptid);

      if (!stopping_threads
	  && requested_child->status_pending_p
	  && requested_child->collecting_fast_tracepoint)
	{
	  enqueue_one_deferred_signal (requested_child,
				       &requested_child->status_pending);
	  requested_child->status_pending_p = 0;
	  requested_child->status_pending = 0;
	  linux_resume_one_lwp (requested_child, 0, 0, NULL);
	}

      if (requested_child->suspended
	  && requested_child->status_pending_p)
	fatal ("requesting an event out of a suspended child?");

      if (requested_child->status_pending_p)
	event_child = requested_child;
    }

  if (event_child != NULL)
    {
      if (debug_threads)
	fprintf (stderr, "Got an event from pending child %ld (%04x)\n",
		 lwpid_of (event_child), event_child->status_pending);
      *wstat = event_child->status_pending;
      event_child->status_pending_p = 0;
      event_child->status_pending = 0;
      current_inferior = get_lwp_thread (event_child);
      return lwpid_of (event_child);
    }

  /* We only enter this loop if no process has a pending wait status.  Thus
     any action taken in response to a wait status inside this loop is
     responding as soon as we detect the status, not after any pending
     events.  */
  while (1)
    {
      event_child = linux_wait_for_lwp (ptid, wstat, options);

      if ((options & WNOHANG) && event_child == NULL)
	{
	  if (debug_threads)
	    fprintf (stderr, "WNOHANG set, no event found\n");
	  return 0;
	}

      if (event_child == NULL)
	error ("event from unknown child");

      current_inferior = get_lwp_thread (event_child);

      /* Check for thread exit.  */
      if (! WIFSTOPPED (*wstat))
	{
	  if (debug_threads)
	    fprintf (stderr, "LWP %ld exiting\n", lwpid_of (event_child));

	  /* If the last thread is exiting, just return.  */
	  if (last_thread_of_process_p (current_inferior))
	    {
	      if (debug_threads)
		fprintf (stderr, "LWP %ld is last lwp of process\n",
			 lwpid_of (event_child));
	      return lwpid_of (event_child);
	    }

	  if (!non_stop)
	    {
	      current_inferior = (struct thread_info *) all_threads.head;
	      if (debug_threads)
		fprintf (stderr, "Current inferior is now %ld\n",
			 lwpid_of (get_thread_lwp (current_inferior)));
	    }
	  else
	    {
	      current_inferior = NULL;
	      if (debug_threads)
		fprintf (stderr, "Current inferior is now <NULL>\n");
	    }

	  /* If we were waiting for this particular child to do something...
	     well, it did something.  */
	  if (requested_child != NULL)
	    {
	      int lwpid = lwpid_of (event_child);

	      /* Cancel the step-over operation --- the thread that
		 started it is gone.  */
	      if (finish_step_over (event_child))
		unstop_all_lwps (1, event_child);
	      delete_lwp (event_child);
	      return lwpid;
	    }

	  delete_lwp (event_child);

	  /* Wait for a more interesting event.  */
	  continue;
	}

      if (event_child->must_set_ptrace_flags)
	{
	  linux_enable_event_reporting (lwpid_of (event_child));
	  event_child->must_set_ptrace_flags = 0;
	}

      if (WIFSTOPPED (*wstat) && WSTOPSIG (*wstat) == SIGTRAP
	  && *wstat >> 16 != 0)
	{
	  handle_extended_wait (event_child, *wstat);
	  continue;
	}

      if (WIFSTOPPED (*wstat)
	  && WSTOPSIG (*wstat) == SIGSTOP
	  && event_child->stop_expected)
	{
	  int should_stop;

	  if (debug_threads)
	    fprintf (stderr, "Expected stop.\n");
	  event_child->stop_expected = 0;

	  should_stop = (current_inferior->last_resume_kind == resume_stop
			 || stopping_threads);

	  if (!should_stop)
	    {
	      linux_resume_one_lwp (event_child,
				    event_child->stepping, 0, NULL);
	      continue;
	    }
	}

      return lwpid_of (event_child);
    }

  /* NOTREACHED */
  return 0;
}

static int
linux_wait_for_event (ptid_t ptid, int *wstat, int options)
{
  ptid_t wait_ptid;

  if (ptid_is_pid (ptid))
    {
      /* A request to wait for a specific tgid.  This is not possible
	 with waitpid, so instead, we wait for any child, and leave
	 children we're not interested in right now with a pending
	 status to report later.  */
      wait_ptid = minus_one_ptid;
    }
  else
    wait_ptid = ptid;

  while (1)
    {
      int event_pid;

      event_pid = linux_wait_for_event_1 (wait_ptid, wstat, options);

      if (event_pid > 0
	  && ptid_is_pid (ptid) && ptid_get_pid (ptid) != event_pid)
	{
	  struct lwp_info *event_child = find_lwp_pid (pid_to_ptid (event_pid));

	  if (! WIFSTOPPED (*wstat))
	    mark_lwp_dead (event_child, *wstat);
	  else
	    {
	      event_child->status_pending_p = 1;
	      event_child->status_pending = *wstat;
	    }
	}
      else
	return event_pid;
    }
}


/* Count the LWP's that have had events.  */

static int
count_events_callback (struct inferior_list_entry *entry, void *data)
{
  struct lwp_info *lp = (struct lwp_info *) entry;
  struct thread_info *thread = get_lwp_thread (lp);
  int *count = data;

  gdb_assert (count != NULL);

  /* Count only resumed LWPs that have a SIGTRAP event pending that
     should be reported to GDB.  */
  if (thread->last_status.kind == TARGET_WAITKIND_IGNORE
      && thread->last_resume_kind != resume_stop
      && lp->status_pending_p
      && WIFSTOPPED (lp->status_pending)
      && WSTOPSIG (lp->status_pending) == SIGTRAP
      && !breakpoint_inserted_here (lp->stop_pc))
    (*count)++;

  return 0;
}

/* Select the LWP (if any) that is currently being single-stepped.  */

static int
select_singlestep_lwp_callback (struct inferior_list_entry *entry, void *data)
{
  struct lwp_info *lp = (struct lwp_info *) entry;
  struct thread_info *thread = get_lwp_thread (lp);

  if (thread->last_status.kind == TARGET_WAITKIND_IGNORE
      && thread->last_resume_kind == resume_step
      && lp->status_pending_p)
    return 1;
  else
    return 0;
}

/* Select the Nth LWP that has had a SIGTRAP event that should be
   reported to GDB.  */

static int
select_event_lwp_callback (struct inferior_list_entry *entry, void *data)
{
  struct lwp_info *lp = (struct lwp_info *) entry;
  struct thread_info *thread = get_lwp_thread (lp);
  int *selector = data;

  gdb_assert (selector != NULL);

  /* Select only resumed LWPs that have a SIGTRAP event pending. */
  if (thread->last_resume_kind != resume_stop
      && thread->last_status.kind == TARGET_WAITKIND_IGNORE
      && lp->status_pending_p
      && WIFSTOPPED (lp->status_pending)
      && WSTOPSIG (lp->status_pending) == SIGTRAP
      && !breakpoint_inserted_here (lp->stop_pc))
    if ((*selector)-- == 0)
      return 1;

  return 0;
}

static int
cancel_breakpoints_callback (struct inferior_list_entry *entry, void *data)
{
  struct lwp_info *lp = (struct lwp_info *) entry;
  struct thread_info *thread = get_lwp_thread (lp);
  struct lwp_info *event_lp = data;

  /* Leave the LWP that has been elected to receive a SIGTRAP alone.  */
  if (lp == event_lp)
    return 0;

  /* If a LWP other than the LWP that we're reporting an event for has
     hit a GDB breakpoint (as opposed to some random trap signal),
     then just arrange for it to hit it again later.  We don't keep
     the SIGTRAP status and don't forward the SIGTRAP signal to the
     LWP.  We will handle the current event, eventually we will resume
     all LWPs, and this one will get its breakpoint trap again.

     If we do not do this, then we run the risk that the user will
     delete or disable the breakpoint, but the LWP will have already
     tripped on it.  */

  if (thread->last_resume_kind != resume_stop
      && thread->last_status.kind == TARGET_WAITKIND_IGNORE
      && lp->status_pending_p
      && WIFSTOPPED (lp->status_pending)
      && WSTOPSIG (lp->status_pending) == SIGTRAP
      && !lp->stepping
      && !lp->stopped_by_watchpoint
      && cancel_breakpoint (lp))
    /* Throw away the SIGTRAP.  */
    lp->status_pending_p = 0;

  return 0;
}

static void
linux_cancel_breakpoints (void)
{
  find_inferior (&all_lwps, cancel_breakpoints_callback, NULL);
}

/* Select one LWP out of those that have events pending.  */

static void
select_event_lwp (struct lwp_info **orig_lp)
{
  int num_events = 0;
  int random_selector;
  struct lwp_info *event_lp;

  /* Give preference to any LWP that is being single-stepped.  */
  event_lp
    = (struct lwp_info *) find_inferior (&all_lwps,
					 select_singlestep_lwp_callback, NULL);
  if (event_lp != NULL)
    {
      if (debug_threads)
	fprintf (stderr,
		 "SEL: Select single-step %s\n",
		 target_pid_to_str (ptid_of (event_lp)));
    }
  else
    {
      /* No single-stepping LWP.  Select one at random, out of those
         which have had SIGTRAP events.  */

      /* First see how many SIGTRAP events we have.  */
      find_inferior (&all_lwps, count_events_callback, &num_events);

      /* Now randomly pick a LWP out of those that have had a SIGTRAP.  */
      random_selector = (int)
	((num_events * (double) rand ()) / (RAND_MAX + 1.0));

      if (debug_threads && num_events > 1)
	fprintf (stderr,
		 "SEL: Found %d SIGTRAP events, selecting #%d\n",
		 num_events, random_selector);

      event_lp = (struct lwp_info *) find_inferior (&all_lwps,
						    select_event_lwp_callback,
						    &random_selector);
    }

  if (event_lp != NULL)
    {
      /* Switch the event LWP.  */
      *orig_lp = event_lp;
    }
}

/* Decrement the suspend count of an LWP.  */

static int
unsuspend_one_lwp (struct inferior_list_entry *entry, void *except)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;

  /* Ignore EXCEPT.  */
  if (lwp == except)
    return 0;

  lwp->suspended--;

  gdb_assert (lwp->suspended >= 0);
  return 0;
}

/* Decrement the suspend count of all LWPs, except EXCEPT, if non
   NULL.  */

static void
unsuspend_all_lwps (struct lwp_info *except)
{
  find_inferior (&all_lwps, unsuspend_one_lwp, except);
}

static void move_out_of_jump_pad_callback (struct inferior_list_entry *entry);
static int stuck_in_jump_pad_callback (struct inferior_list_entry *entry,
				       void *data);
static int lwp_running (struct inferior_list_entry *entry, void *data);
static ptid_t linux_wait_1 (ptid_t ptid,
			    struct target_waitstatus *ourstatus,
			    int target_options);

/* Stabilize threads (move out of jump pads).

   If a thread is midway collecting a fast tracepoint, we need to
   finish the collection and move it out of the jump pad before
   reporting the signal.

   This avoids recursion while collecting (when a signal arrives
   midway, and the signal handler itself collects), which would trash
   the trace buffer.  In case the user set a breakpoint in a signal
   handler, this avoids the backtrace showing the jump pad, etc..
   Most importantly, there are certain things we can't do safely if
   threads are stopped in a jump pad (or in its callee's).  For
   example:

     - starting a new trace run.  A thread still collecting the
   previous run, could trash the trace buffer when resumed.  The trace
   buffer control structures would have been reset but the thread had
   no way to tell.  The thread could even midway memcpy'ing to the
   buffer, which would mean that when resumed, it would clobber the
   trace buffer that had been set for a new run.

     - we can't rewrite/reuse the jump pads for new tracepoints
   safely.  Say you do tstart while a thread is stopped midway while
   collecting.  When the thread is later resumed, it finishes the
   collection, and returns to the jump pad, to execute the original
   instruction that was under the tracepoint jump at the time the
   older run had been started.  If the jump pad had been rewritten
   since for something else in the new run, the thread would now
   execute the wrong / random instructions.  */

static void
linux_stabilize_threads (void)
{
  struct thread_info *save_inferior;
  struct lwp_info *lwp_stuck;

  lwp_stuck
    = (struct lwp_info *) find_inferior (&all_lwps,
					 stuck_in_jump_pad_callback, NULL);
  if (lwp_stuck != NULL)
    {
      fprintf (stderr, "can't stabilize, LWP %ld is stuck in jump pad\n",
	       lwpid_of (lwp_stuck));
      return;
    }

  save_inferior = current_inferior;

  stabilizing_threads = 1;

  /* Kick 'em all.  */
  for_each_inferior (&all_lwps, move_out_of_jump_pad_callback);

  /* Loop until all are stopped out of the jump pads.  */
  while (find_inferior (&all_lwps, lwp_running, NULL) != NULL)
    {
      struct target_waitstatus ourstatus;
      struct lwp_info *lwp;
      ptid_t ptid;
      int wstat;

      /* Note that we go through the full wait even loop.  While
	 moving threads out of jump pad, we need to be able to step
	 over internal breakpoints and such.  */
      ptid = linux_wait_1 (minus_one_ptid, &ourstatus, 0);

      if (ourstatus.kind == TARGET_WAITKIND_STOPPED)
	{
	  lwp = get_thread_lwp (current_inferior);

	  /* Lock it.  */
	  lwp->suspended++;

	  if (ourstatus.value.sig != TARGET_SIGNAL_0
	      || current_inferior->last_resume_kind == resume_stop)
	    {
	      wstat = W_STOPCODE (target_signal_to_host (ourstatus.value.sig));
	      enqueue_one_deferred_signal (lwp, &wstat);
	    }
	}
    }

  find_inferior (&all_lwps, unsuspend_one_lwp, NULL);

  stabilizing_threads = 0;

  current_inferior = save_inferior;

  lwp_stuck
    = (struct lwp_info *) find_inferior (&all_lwps,
					 stuck_in_jump_pad_callback, NULL);
  if (lwp_stuck != NULL)
    {
      if (debug_threads)
	fprintf (stderr, "couldn't stabilize, LWP %ld got stuck in jump pad\n",
		 lwpid_of (lwp_stuck));
    }
}

/* Wait for process, returns status.  */

static ptid_t
linux_wait_1 (ptid_t ptid,
	      struct target_waitstatus *ourstatus, int target_options)
{
  int w;
  struct lwp_info *event_child;
  int options;
  int pid;
  int step_over_finished;
  int bp_explains_trap;
  int maybe_internal_trap;
  int report_to_gdb;
  int trace_event;

  /* Translate generic target options into linux options.  */
  options = __WALL;
  if (target_options & TARGET_WNOHANG)
    options |= WNOHANG;

retry:
  bp_explains_trap = 0;
  trace_event = 0;
  ourstatus->kind = TARGET_WAITKIND_IGNORE;

  /* If we were only supposed to resume one thread, only wait for
     that thread - if it's still alive.  If it died, however - which
     can happen if we're coming from the thread death case below -
     then we need to make sure we restart the other threads.  We could
     pick a thread at random or restart all; restarting all is less
     arbitrary.  */
  if (!non_stop
      && !ptid_equal (cont_thread, null_ptid)
      && !ptid_equal (cont_thread, minus_one_ptid))
    {
      struct thread_info *thread;

      thread = (struct thread_info *) find_inferior_id (&all_threads,
							cont_thread);

      /* No stepping, no signal - unless one is pending already, of course.  */
      if (thread == NULL)
	{
	  struct thread_resume resume_info;
	  resume_info.thread = minus_one_ptid;
	  resume_info.kind = resume_continue;
	  resume_info.sig = 0;
	  linux_resume (&resume_info, 1);
	}
      else
	ptid = cont_thread;
    }

  if (ptid_equal (step_over_bkpt, null_ptid))
    pid = linux_wait_for_event (ptid, &w, options);
  else
    {
      if (debug_threads)
	fprintf (stderr, "step_over_bkpt set [%s], doing a blocking wait\n",
		 target_pid_to_str (step_over_bkpt));
      pid = linux_wait_for_event (step_over_bkpt, &w, options & ~WNOHANG);
    }

  if (pid == 0) /* only if TARGET_WNOHANG */
    return null_ptid;

  event_child = get_thread_lwp (current_inferior);

  /* If we are waiting for a particular child, and it exited,
     linux_wait_for_event will return its exit status.  Similarly if
     the last child exited.  If this is not the last child, however,
     do not report it as exited until there is a 'thread exited' response
     available in the remote protocol.  Instead, just wait for another event.
     This should be safe, because if the thread crashed we will already
     have reported the termination signal to GDB; that should stop any
     in-progress stepping operations, etc.

     Report the exit status of the last thread to exit.  This matches
     LinuxThreads' behavior.  */

  if (last_thread_of_process_p (current_inferior))
    {
      if (WIFEXITED (w) || WIFSIGNALED (w))
	{
	  if (WIFEXITED (w))
	    {
	      ourstatus->kind = TARGET_WAITKIND_EXITED;
	      ourstatus->value.integer = WEXITSTATUS (w);

	      if (debug_threads)
		fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
	    }
	  else
	    {
	      ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
	      ourstatus->value.sig = target_signal_from_host (WTERMSIG (w));

	      if (debug_threads)
		fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));

	    }

	  return ptid_of (event_child);
	}
    }
  else
    {
      if (!WIFSTOPPED (w))
	goto retry;
    }

  /* If this event was not handled before, and is not a SIGTRAP, we
     report it.  SIGILL and SIGSEGV are also treated as traps in case
     a breakpoint is inserted at the current PC.  If this target does
     not support internal breakpoints at all, we also report the
     SIGTRAP without further processing; it's of no concern to us.  */
  maybe_internal_trap
    = (supports_breakpoints ()
       && (WSTOPSIG (w) == SIGTRAP
	   || ((WSTOPSIG (w) == SIGILL
		|| WSTOPSIG (w) == SIGSEGV)
	       && (*the_low_target.breakpoint_at) (event_child->stop_pc))));

  if (maybe_internal_trap)
    {
      /* Handle anything that requires bookkeeping before deciding to
	 report the event or continue waiting.  */

      /* First check if we can explain the SIGTRAP with an internal
	 breakpoint, or if we should possibly report the event to GDB.
	 Do this before anything that may remove or insert a
	 breakpoint.  */
      bp_explains_trap = breakpoint_inserted_here (event_child->stop_pc);

      /* We have a SIGTRAP, possibly a step-over dance has just
	 finished.  If so, tweak the state machine accordingly,
	 reinsert breakpoints and delete any reinsert (software
	 single-step) breakpoints.  */
      step_over_finished = finish_step_over (event_child);

      /* Now invoke the callbacks of any internal breakpoints there.  */
      check_breakpoints (event_child->stop_pc);

      /* Handle tracepoint data collecting.  This may overflow the
	 trace buffer, and cause a tracing stop, removing
	 breakpoints.  */
      trace_event = handle_tracepoints (event_child);

      if (bp_explains_trap)
	{
	  /* If we stepped or ran into an internal breakpoint, we've
	     already handled it.  So next time we resume (from this
	     PC), we should step over it.  */
	  if (debug_threads)
	    fprintf (stderr, "Hit a gdbserver breakpoint.\n");

	  if (breakpoint_here (event_child->stop_pc))
	    event_child->need_step_over = 1;
	}
    }
  else
    {
      /* We have some other signal, possibly a step-over dance was in
	 progress, and it should be cancelled too.  */
      step_over_finished = finish_step_over (event_child);
    }

  /* We have all the data we need.  Either report the event to GDB, or
     resume threads and keep waiting for more.  */

  /* If we're collecting a fast tracepoint, finish the collection and
     move out of the jump pad before delivering a signal.  See
     linux_stabilize_threads.  */

  if (WIFSTOPPED (w)
      && WSTOPSIG (w) != SIGTRAP
      && supports_fast_tracepoints ()
      && in_process_agent_loaded ())
    {
      if (debug_threads)
	fprintf (stderr,
		 "Got signal %d for LWP %ld.  Check if we need "
		 "to defer or adjust it.\n",
		 WSTOPSIG (w), lwpid_of (event_child));

      /* Allow debugging the jump pad itself.  */
      if (current_inferior->last_resume_kind != resume_step
	  && maybe_move_out_of_jump_pad (event_child, &w))
	{
	  enqueue_one_deferred_signal (event_child, &w);

	  if (debug_threads)
	    fprintf (stderr,
		     "Signal %d for LWP %ld deferred (in jump pad)\n",
		     WSTOPSIG (w), lwpid_of (event_child));

	  linux_resume_one_lwp (event_child, 0, 0, NULL);
	  goto retry;
	}
    }

  if (event_child->collecting_fast_tracepoint)
    {
      if (debug_threads)
	fprintf (stderr, "\
LWP %ld was trying to move out of the jump pad (%d).  \
Check if we're already there.\n",
		 lwpid_of (event_child),
		 event_child->collecting_fast_tracepoint);

      trace_event = 1;

      event_child->collecting_fast_tracepoint
	= linux_fast_tracepoint_collecting (event_child, NULL);

      if (event_child->collecting_fast_tracepoint != 1)
	{
	  /* No longer need this breakpoint.  */
	  if (event_child->exit_jump_pad_bkpt != NULL)
	    {
	      if (debug_threads)
		fprintf (stderr,
			 "No longer need exit-jump-pad bkpt; removing it."
			 "stopping all threads momentarily.\n");

	      /* Other running threads could hit this breakpoint.
		 We don't handle moribund locations like GDB does,
		 instead we always pause all threads when removing
		 breakpoints, so that any step-over or
		 decr_pc_after_break adjustment is always taken
		 care of while the breakpoint is still
		 inserted.  */
	      stop_all_lwps (1, event_child);
	      cancel_breakpoints ();

	      delete_breakpoint (event_child->exit_jump_pad_bkpt);
	      event_child->exit_jump_pad_bkpt = NULL;

	      unstop_all_lwps (1, event_child);

	      gdb_assert (event_child->suspended >= 0);
	    }
	}

      if (event_child->collecting_fast_tracepoint == 0)
	{
	  if (debug_threads)
	    fprintf (stderr,
		     "fast tracepoint finished "
		     "collecting successfully.\n");

	  /* We may have a deferred signal to report.  */
	  if (dequeue_one_deferred_signal (event_child, &w))
	    {
	      if (debug_threads)
		fprintf (stderr, "dequeued one signal.\n");
	    }
	  else if (debug_threads)
	    {
	      fprintf (stderr, "no deferred signals.\n");

	      if (stabilizing_threads)
		{
		  ourstatus->kind = TARGET_WAITKIND_STOPPED;
		  ourstatus->value.sig = TARGET_SIGNAL_0;
		  return ptid_of (event_child);
		}
	    }
	}
    }

  /* Check whether GDB would be interested in this event.  */

  /* If GDB is not interested in this signal, don't stop other
     threads, and don't report it to GDB.  Just resume the inferior
     right away.  We do this for threading-related signals as well as
     any that GDB specifically requested we ignore.  But never ignore
     SIGSTOP if we sent it ourselves, and do not ignore signals when
     stepping - they may require special handling to skip the signal
     handler.  */
  /* FIXME drow/2002-06-09: Get signal numbers from the inferior's
     thread library?  */
  if (WIFSTOPPED (w)
      && current_inferior->last_resume_kind != resume_step
      && (
#if defined (USE_THREAD_DB) && defined (__SIGRTMIN)
	  (current_process ()->private->thread_db != NULL
	   && (WSTOPSIG (w) == __SIGRTMIN
	       || WSTOPSIG (w) == __SIGRTMIN + 1))
	  ||
#endif
	  (pass_signals[target_signal_from_host (WSTOPSIG (w))]
	   && !(WSTOPSIG (w) == SIGSTOP
		&& current_inferior->last_resume_kind == resume_stop))))
    {
      siginfo_t info, *info_p;

      if (debug_threads)
	fprintf (stderr, "Ignored signal %d for LWP %ld.\n",
		 WSTOPSIG (w), lwpid_of (event_child));

      if (ptrace (PTRACE_GETSIGINFO, lwpid_of (event_child), 0, &info) == 0)
	info_p = &info;
      else
	info_p = NULL;
      linux_resume_one_lwp (event_child, event_child->stepping,
			    WSTOPSIG (w), info_p);
      goto retry;
    }

  /* If GDB wanted this thread to single step, we always want to
     report the SIGTRAP, and let GDB handle it.  Watchpoints should
     always be reported.  So should signals we can't explain.  A
     SIGTRAP we can't explain could be a GDB breakpoint --- we may or
     not support Z0 breakpoints.  If we do, we're be able to handle
     GDB breakpoints on top of internal breakpoints, by handling the
     internal breakpoint and still reporting the event to GDB.  If we
     don't, we're out of luck, GDB won't see the breakpoint hit.  */
  report_to_gdb = (!maybe_internal_trap
		   || current_inferior->last_resume_kind == resume_step
		   || event_child->stopped_by_watchpoint
		   || (!step_over_finished && !bp_explains_trap && !trace_event)
		   || gdb_breakpoint_here (event_child->stop_pc));

  /* We found no reason GDB would want us to stop.  We either hit one
     of our own breakpoints, or finished an internal step GDB
     shouldn't know about.  */
  if (!report_to_gdb)
    {
      if (debug_threads)
	{
	  if (bp_explains_trap)
	    fprintf (stderr, "Hit a gdbserver breakpoint.\n");
	  if (step_over_finished)
	    fprintf (stderr, "Step-over finished.\n");
	  if (trace_event)
	    fprintf (stderr, "Tracepoint event.\n");
	}

      /* We're not reporting this breakpoint to GDB, so apply the
	 decr_pc_after_break adjustment to the inferior's regcache
	 ourselves.  */

      if (the_low_target.set_pc != NULL)
	{
	  struct regcache *regcache
	    = get_thread_regcache (get_lwp_thread (event_child), 1);
	  (*the_low_target.set_pc) (regcache, event_child->stop_pc);
	}

      /* We may have finished stepping over a breakpoint.  If so,
	 we've stopped and suspended all LWPs momentarily except the
	 stepping one.  This is where we resume them all again.  We're
	 going to keep waiting, so use proceed, which handles stepping
	 over the next breakpoint.  */
      if (debug_threads)
	fprintf (stderr, "proceeding all threads.\n");

      if (step_over_finished)
	unsuspend_all_lwps (event_child);

      proceed_all_lwps ();
      goto retry;
    }

  if (debug_threads)
    {
      if (current_inferior->last_resume_kind == resume_step)
	fprintf (stderr, "GDB wanted to single-step, reporting event.\n");
      if (event_child->stopped_by_watchpoint)
	fprintf (stderr, "Stopped by watchpoint.\n");
      if (gdb_breakpoint_here (event_child->stop_pc))
	fprintf (stderr, "Stopped by GDB breakpoint.\n");
      if (debug_threads)
	fprintf (stderr, "Hit a non-gdbserver trap event.\n");
    }

  /* Alright, we're going to report a stop.  */

  if (!non_stop && !stabilizing_threads)
    {
      /* In all-stop, stop all threads.  */
      stop_all_lwps (0, NULL);

      /* If we're not waiting for a specific LWP, choose an event LWP
	 from among those that have had events.  Giving equal priority
	 to all LWPs that have had events helps prevent
	 starvation.  */
      if (ptid_equal (ptid, minus_one_ptid))
	{
	  event_child->status_pending_p = 1;
	  event_child->status_pending = w;

	  select_event_lwp (&event_child);

	  event_child->status_pending_p = 0;
	  w = event_child->status_pending;
	}

      /* Now that we've selected our final event LWP, cancel any
	 breakpoints in other LWPs that have hit a GDB breakpoint.
	 See the comment in cancel_breakpoints_callback to find out
	 why.  */
      find_inferior (&all_lwps, cancel_breakpoints_callback, event_child);

      /* Stabilize threads (move out of jump pads).  */
      stabilize_threads ();
    }
  else
    {
      /* If we just finished a step-over, then all threads had been
	 momentarily paused.  In all-stop, that's fine, we want
	 threads stopped by now anyway.  In non-stop, we need to
	 re-resume threads that GDB wanted to be running.  */
      if (step_over_finished)
	unstop_all_lwps (1, event_child);
    }

  ourstatus->kind = TARGET_WAITKIND_STOPPED;

  if (current_inferior->last_resume_kind == resume_stop
      && WSTOPSIG (w) == SIGSTOP)
    {
      /* A thread that has been requested to stop by GDB with vCont;t,
	 and it stopped cleanly, so report as SIG0.  The use of
	 SIGSTOP is an implementation detail.  */
      ourstatus->value.sig = TARGET_SIGNAL_0;
    }
  else if (current_inferior->last_resume_kind == resume_stop
	   && WSTOPSIG (w) != SIGSTOP)
    {
      /* A thread that has been requested to stop by GDB with vCont;t,
	 but, it stopped for other reasons.  */
      ourstatus->value.sig = target_signal_from_host (WSTOPSIG (w));
    }
  else
    {
      ourstatus->value.sig = target_signal_from_host (WSTOPSIG (w));
    }

  gdb_assert (ptid_equal (step_over_bkpt, null_ptid));

  if (debug_threads)
    fprintf (stderr, "linux_wait ret = %s, %d, %d\n",
	     target_pid_to_str (ptid_of (event_child)),
	     ourstatus->kind,
	     ourstatus->value.sig);

  if (!stabilizing_threads)
    current_inferior->last_status = *ourstatus;

  return ptid_of (event_child);
}

/* Get rid of any pending event in the pipe.  */
static void
async_file_flush (void)
{
  int ret;
  char buf;

  do
    ret = read (linux_event_pipe[0], &buf, 1);
  while (ret >= 0 || (ret == -1 && errno == EINTR));
}

/* Put something in the pipe, so the event loop wakes up.  */
static void
async_file_mark (void)
{
  int ret;

  async_file_flush ();

  do
    ret = write (linux_event_pipe[1], "+", 1);
  while (ret == 0 || (ret == -1 && errno == EINTR));

  /* Ignore EAGAIN.  If the pipe is full, the event loop will already
     be awakened anyway.  */
}

static ptid_t
linux_wait (ptid_t ptid,
	    struct target_waitstatus *ourstatus, int target_options)
{
  ptid_t event_ptid;

  if (debug_threads)
    fprintf (stderr, "linux_wait: [%s]\n", target_pid_to_str (ptid));

  /* Flush the async file first.  */
  if (target_is_async_p ())
    async_file_flush ();

  event_ptid = linux_wait_1 (ptid, ourstatus, target_options);

  /* If at least one stop was reported, there may be more.  A single
     SIGCHLD can signal more than one child stop.  */
  if (target_is_async_p ()
      && (target_options & TARGET_WNOHANG) != 0
      && !ptid_equal (event_ptid, null_ptid))
    async_file_mark ();

  return event_ptid;
}

/* Send a signal to an LWP.  */

static int
kill_lwp (unsigned long lwpid, int signo)
{
  /* Use tkill, if possible, in case we are using nptl threads.  If tkill
     fails, then we are not using nptl threads and we should be using kill.  */

#ifdef __NR_tkill
  {
    static int tkill_failed;

    if (!tkill_failed)
      {
	int ret;

	errno = 0;
	ret = syscall (__NR_tkill, lwpid, signo);
	if (errno != ENOSYS)
	  return ret;
	tkill_failed = 1;
      }
  }
#endif

  return kill (lwpid, signo);
}

void
linux_stop_lwp (struct lwp_info *lwp)
{
  send_sigstop (lwp);
}

static void
send_sigstop (struct lwp_info *lwp)
{
  int pid;

  pid = lwpid_of (lwp);

  /* If we already have a pending stop signal for this process, don't
     send another.  */
  if (lwp->stop_expected)
    {
      if (debug_threads)
	fprintf (stderr, "Have pending sigstop for lwp %d\n", pid);

      return;
    }

  if (debug_threads)
    fprintf (stderr, "Sending sigstop to lwp %d\n", pid);

  lwp->stop_expected = 1;
  kill_lwp (pid, SIGSTOP);
}

static int
send_sigstop_callback (struct inferior_list_entry *entry, void *except)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;

  /* Ignore EXCEPT.  */
  if (lwp == except)
    return 0;

  if (lwp->stopped)
    return 0;

  send_sigstop (lwp);
  return 0;
}

/* Increment the suspend count of an LWP, and stop it, if not stopped
   yet.  */
static int
suspend_and_send_sigstop_callback (struct inferior_list_entry *entry,
				   void *except)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;

  /* Ignore EXCEPT.  */
  if (lwp == except)
    return 0;

  lwp->suspended++;

  return send_sigstop_callback (entry, except);
}

static void
mark_lwp_dead (struct lwp_info *lwp, int wstat)
{
  /* It's dead, really.  */
  lwp->dead = 1;

  /* Store the exit status for later.  */
  lwp->status_pending_p = 1;
  lwp->status_pending = wstat;

  /* Prevent trying to stop it.  */
  lwp->stopped = 1;

  /* No further stops are expected from a dead lwp.  */
  lwp->stop_expected = 0;
}

static void
wait_for_sigstop (struct inferior_list_entry *entry)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;
  struct thread_info *saved_inferior;
  int wstat;
  ptid_t saved_tid;
  ptid_t ptid;
  int pid;

  if (lwp->stopped)
    {
      if (debug_threads)
	fprintf (stderr, "wait_for_sigstop: LWP %ld already stopped\n",
		 lwpid_of (lwp));
      return;
    }

  saved_inferior = current_inferior;
  if (saved_inferior != NULL)
    saved_tid = ((struct inferior_list_entry *) saved_inferior)->id;
  else
    saved_tid = null_ptid; /* avoid bogus unused warning */

  ptid = lwp->head.id;

  if (debug_threads)
    fprintf (stderr, "wait_for_sigstop: pulling one event\n");

  pid = linux_wait_for_event (ptid, &wstat, __WALL);

  /* If we stopped with a non-SIGSTOP signal, save it for later
     and record the pending SIGSTOP.  If the process exited, just
     return.  */
  if (WIFSTOPPED (wstat))
    {
      if (debug_threads)
	fprintf (stderr, "LWP %ld stopped with signal %d\n",
		 lwpid_of (lwp), WSTOPSIG (wstat));

      if (WSTOPSIG (wstat) != SIGSTOP)
	{
	  if (debug_threads)
	    fprintf (stderr, "LWP %ld stopped with non-sigstop status %06x\n",
		     lwpid_of (lwp), wstat);

	  lwp->status_pending_p = 1;
	  lwp->status_pending = wstat;
	}
    }
  else
    {
      if (debug_threads)
	fprintf (stderr, "Process %d exited while stopping LWPs\n", pid);

      lwp = find_lwp_pid (pid_to_ptid (pid));
      if (lwp)
	{
	  /* Leave this status pending for the next time we're able to
	     report it.  In the mean time, we'll report this lwp as
	     dead to GDB, so GDB doesn't try to read registers and
	     memory from it.  This can only happen if this was the
	     last thread of the process; otherwise, PID is removed
	     from the thread tables before linux_wait_for_event
	     returns.  */
	  mark_lwp_dead (lwp, wstat);
	}
    }

  if (saved_inferior == NULL || linux_thread_alive (saved_tid))
    current_inferior = saved_inferior;
  else
    {
      if (debug_threads)
	fprintf (stderr, "Previously current thread died.\n");

      if (non_stop)
	{
	  /* We can't change the current inferior behind GDB's back,
	     otherwise, a subsequent command may apply to the wrong
	     process.  */
	  current_inferior = NULL;
	}
      else
	{
	  /* Set a valid thread as current.  */
	  set_desired_inferior (0);
	}
    }
}

/* Returns true if LWP ENTRY is stopped in a jump pad, and we can't
   move it out, because we need to report the stop event to GDB.  For
   example, if the user puts a breakpoint in the jump pad, it's
   because she wants to debug it.  */

static int
stuck_in_jump_pad_callback (struct inferior_list_entry *entry, void *data)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;
  struct thread_info *thread = get_lwp_thread (lwp);

  gdb_assert (lwp->suspended == 0);
  gdb_assert (lwp->stopped);

  /* Allow debugging the jump pad, gdb_collect, etc..  */
  return (supports_fast_tracepoints ()
	  && in_process_agent_loaded ()
	  && (gdb_breakpoint_here (lwp->stop_pc)
	      || lwp->stopped_by_watchpoint
	      || thread->last_resume_kind == resume_step)
	  && linux_fast_tracepoint_collecting (lwp, NULL));
}

static void
move_out_of_jump_pad_callback (struct inferior_list_entry *entry)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;
  struct thread_info *thread = get_lwp_thread (lwp);
  int *wstat;

  gdb_assert (lwp->suspended == 0);
  gdb_assert (lwp->stopped);

  wstat = lwp->status_pending_p ? &lwp->status_pending : NULL;

  /* Allow debugging the jump pad, gdb_collect, etc.  */
  if (!gdb_breakpoint_here (lwp->stop_pc)
      && !lwp->stopped_by_watchpoint
      && thread->last_resume_kind != resume_step
      && maybe_move_out_of_jump_pad (lwp, wstat))
    {
      if (debug_threads)
	fprintf (stderr,
		 "LWP %ld needs stabilizing (in jump pad)\n",
		 lwpid_of (lwp));

      if (wstat)
	{
	  lwp->status_pending_p = 0;
	  enqueue_one_deferred_signal (lwp, wstat);

	  if (debug_threads)
	    fprintf (stderr,
		     "Signal %d for LWP %ld deferred "
		     "(in jump pad)\n",
		     WSTOPSIG (*wstat), lwpid_of (lwp));
	}

      linux_resume_one_lwp (lwp, 0, 0, NULL);
    }
  else
    lwp->suspended++;
}

static int
lwp_running (struct inferior_list_entry *entry, void *data)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;

  if (lwp->dead)
    return 0;
  if (lwp->stopped)
    return 0;
  return 1;
}

/* Stop all lwps that aren't stopped yet, except EXCEPT, if not NULL.
   If SUSPEND, then also increase the suspend count of every LWP,
   except EXCEPT.  */

static void
stop_all_lwps (int suspend, struct lwp_info *except)
{
  stopping_threads = 1;

  if (suspend)
    find_inferior (&all_lwps, suspend_and_send_sigstop_callback, except);
  else
    find_inferior (&all_lwps, send_sigstop_callback, except);
  for_each_inferior (&all_lwps, wait_for_sigstop);
  stopping_threads = 0;
}

/* Resume execution of the inferior process.
   If STEP is nonzero, single-step it.
   If SIGNAL is nonzero, give it that signal.  */

static void
linux_resume_one_lwp (struct lwp_info *lwp,
		      int step, int signal, siginfo_t *info)
{
  struct thread_info *saved_inferior;
  int fast_tp_collecting;

  if (lwp->stopped == 0)
    return;

  fast_tp_collecting = lwp->collecting_fast_tracepoint;

  gdb_assert (!stabilizing_threads || fast_tp_collecting);

  /* Cancel actions that rely on GDB not changing the PC (e.g., the
     user used the "jump" command, or "set $pc = foo").  */
  if (lwp->stop_pc != get_pc (lwp))
    {
      /* Collecting 'while-stepping' actions doesn't make sense
	 anymore.  */
      release_while_stepping_state_list (get_lwp_thread (lwp));
    }

  /* If we have pending signals or status, and a new signal, enqueue the
     signal.  Also enqueue the signal if we are waiting to reinsert a
     breakpoint; it will be picked up again below.  */
  if (signal != 0
      && (lwp->status_pending_p
	  || lwp->pending_signals != NULL
	  || lwp->bp_reinsert != 0
	  || fast_tp_collecting))
    {
      struct pending_signals *p_sig;
      p_sig = xmalloc (sizeof (*p_sig));
      p_sig->prev = lwp->pending_signals;
      p_sig->signal = signal;
      if (info == NULL)
	memset (&p_sig->info, 0, sizeof (siginfo_t));
      else
	memcpy (&p_sig->info, info, sizeof (siginfo_t));
      lwp->pending_signals = p_sig;
    }

  if (lwp->status_pending_p)
    {
      if (debug_threads)
	fprintf (stderr, "Not resuming lwp %ld (%s, signal %d, stop %s);"
		 " has pending status\n",
		 lwpid_of (lwp), step ? "step" : "continue", signal,
		 lwp->stop_expected ? "expected" : "not expected");
      return;
    }

  saved_inferior = current_inferior;
  current_inferior = get_lwp_thread (lwp);

  if (debug_threads)
    fprintf (stderr, "Resuming lwp %ld (%s, signal %d, stop %s)\n",
	     lwpid_of (lwp), step ? "step" : "continue", signal,
	     lwp->stop_expected ? "expected" : "not expected");

  /* This bit needs some thinking about.  If we get a signal that
     we must report while a single-step reinsert is still pending,
     we often end up resuming the thread.  It might be better to
     (ew) allow a stack of pending events; then we could be sure that
     the reinsert happened right away and not lose any signals.

     Making this stack would also shrink the window in which breakpoints are
     uninserted (see comment in linux_wait_for_lwp) but not enough for
     complete correctness, so it won't solve that problem.  It may be
     worthwhile just to solve this one, however.  */
  if (lwp->bp_reinsert != 0)
    {
      if (debug_threads)
	fprintf (stderr, "  pending reinsert at 0x%s\n",
		 paddress (lwp->bp_reinsert));

      if (lwp->bp_reinsert != 0 && can_hardware_single_step ())
	{
	  if (fast_tp_collecting == 0)
	    {
	      if (step == 0)
		fprintf (stderr, "BAD - reinserting but not stepping.\n");
	      if (lwp->suspended)
		fprintf (stderr, "BAD - reinserting and suspended(%d).\n",
			 lwp->suspended);
	    }

	  step = 1;
	}

      /* Postpone any pending signal.  It was enqueued above.  */
      signal = 0;
    }

  if (fast_tp_collecting == 1)
    {
      if (debug_threads)
	fprintf (stderr, "\
lwp %ld wants to get out of fast tracepoint jump pad (exit-jump-pad-bkpt)\n",
		 lwpid_of (lwp));

      /* Postpone any pending signal.  It was enqueued above.  */
      signal = 0;
    }
  else if (fast_tp_collecting == 2)
    {
      if (debug_threads)
	fprintf (stderr, "\
lwp %ld wants to get out of fast tracepoint jump pad single-stepping\n",
		 lwpid_of (lwp));

      if (can_hardware_single_step ())
	step = 1;
      else
	fatal ("moving out of jump pad single-stepping"
	       " not implemented on this target");

      /* Postpone any pending signal.  It was enqueued above.  */
      signal = 0;
    }

  /* If we have while-stepping actions in this thread set it stepping.
     If we have a signal to deliver, it may or may not be set to
     SIG_IGN, we don't know.  Assume so, and allow collecting
     while-stepping into a signal handler.  A possible smart thing to
     do would be to set an internal breakpoint at the signal return
     address, continue, and carry on catching this while-stepping
     action only when that breakpoint is hit.  A future
     enhancement.  */
  if (get_lwp_thread (lwp)->while_stepping != NULL
      && can_hardware_single_step ())
    {
      if (debug_threads)
	fprintf (stderr,
		 "lwp %ld has a while-stepping action -> forcing step.\n",
		 lwpid_of (lwp));
      step = 1;
    }

  if (debug_threads && the_low_target.get_pc != NULL)
    {
      struct regcache *regcache = get_thread_regcache (current_inferior, 1);
      CORE_ADDR pc = (*the_low_target.get_pc) (regcache);
      fprintf (stderr, "  resuming from pc 0x%lx\n", (long) pc);
    }

  /* If we have pending signals, consume one unless we are trying to
     reinsert a breakpoint or we're trying to finish a fast tracepoint
     collect.  */
  if (lwp->pending_signals != NULL
      && lwp->bp_reinsert == 0
      && fast_tp_collecting == 0)
    {
      struct pending_signals **p_sig;

      p_sig = &lwp->pending_signals;
      while ((*p_sig)->prev != NULL)
	p_sig = &(*p_sig)->prev;

      signal = (*p_sig)->signal;
      if ((*p_sig)->info.si_signo != 0)
	ptrace (PTRACE_SETSIGINFO, lwpid_of (lwp), 0, &(*p_sig)->info);

      free (*p_sig);
      *p_sig = NULL;
    }

  if (the_low_target.prepare_to_resume != NULL)
    the_low_target.prepare_to_resume (lwp);

  regcache_invalidate_one ((struct inferior_list_entry *)
			   get_lwp_thread (lwp));
  errno = 0;
  lwp->stopped = 0;
  lwp->stopped_by_watchpoint = 0;
  lwp->stepping = step;
  ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, lwpid_of (lwp), 0,
	  /* Coerce to a uintptr_t first to avoid potential gcc warning
	     of coercing an 8 byte integer to a 4 byte pointer.  */
	  (PTRACE_ARG4_TYPE) (uintptr_t) signal);

  current_inferior = saved_inferior;
  if (errno)
    {
      /* ESRCH from ptrace either means that the thread was already
	 running (an error) or that it is gone (a race condition).  If
	 it's gone, we will get a notification the next time we wait,
	 so we can ignore the error.  We could differentiate these
	 two, but it's tricky without waiting; the thread still exists
	 as a zombie, so sending it signal 0 would succeed.  So just
	 ignore ESRCH.  */
      if (errno == ESRCH)
	return;

      perror_with_name ("ptrace");
    }
}

struct thread_resume_array
{
  struct thread_resume *resume;
  size_t n;
};

/* This function is called once per thread.  We look up the thread
   in RESUME_PTR, and mark the thread with a pointer to the appropriate
   resume request.

   This algorithm is O(threads * resume elements), but resume elements
   is small (and will remain small at least until GDB supports thread
   suspension).  */
static int
linux_set_resume_request (struct inferior_list_entry *entry, void *arg)
{
  struct lwp_info *lwp;
  struct thread_info *thread;
  int ndx;
  struct thread_resume_array *r;

  thread = (struct thread_info *) entry;
  lwp = get_thread_lwp (thread);
  r = arg;

  for (ndx = 0; ndx < r->n; ndx++)
    {
      ptid_t ptid = r->resume[ndx].thread;
      if (ptid_equal (ptid, minus_one_ptid)
	  || ptid_equal (ptid, entry->id)
	  || (ptid_is_pid (ptid)
	      && (ptid_get_pid (ptid) == pid_of (lwp)))
	  || (ptid_get_lwp (ptid) == -1
	      && (ptid_get_pid (ptid) == pid_of (lwp))))
	{
	  if (r->resume[ndx].kind == resume_stop
	      && thread->last_resume_kind == resume_stop)
	    {
	      if (debug_threads)
		fprintf (stderr, "already %s LWP %ld at GDB's request\n",
			 thread->last_status.kind == TARGET_WAITKIND_STOPPED
			 ? "stopped"
			 : "stopping",
			 lwpid_of (lwp));

	      continue;
	    }

	  lwp->resume = &r->resume[ndx];
	  thread->last_resume_kind = lwp->resume->kind;

	  /* If we had a deferred signal to report, dequeue one now.
	     This can happen if LWP gets more than one signal while
	     trying to get out of a jump pad.  */
	  if (lwp->stopped
	      && !lwp->status_pending_p
	      && dequeue_one_deferred_signal (lwp, &lwp->status_pending))
	    {
	      lwp->status_pending_p = 1;

	      if (debug_threads)
		fprintf (stderr,
			 "Dequeueing deferred signal %d for LWP %ld, "
			 "leaving status pending.\n",
			 WSTOPSIG (lwp->status_pending), lwpid_of (lwp));
	    }

	  return 0;
	}
    }

  /* No resume action for this thread.  */
  lwp->resume = NULL;

  return 0;
}


/* Set *FLAG_P if this lwp has an interesting status pending.  */
static int
resume_status_pending_p (struct inferior_list_entry *entry, void *flag_p)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;

  /* LWPs which will not be resumed are not interesting, because
     we might not wait for them next time through linux_wait.  */
  if (lwp->resume == NULL)
    return 0;

  if (lwp->status_pending_p)
    * (int *) flag_p = 1;

  return 0;
}

/* Return 1 if this lwp that GDB wants running is stopped at an
   internal breakpoint that we need to step over.  It assumes that any
   required STOP_PC adjustment has already been propagated to the
   inferior's regcache.  */

static int
need_step_over_p (struct inferior_list_entry *entry, void *dummy)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;
  struct thread_info *thread;
  struct thread_info *saved_inferior;
  CORE_ADDR pc;

  /* LWPs which will not be resumed are not interesting, because we
     might not wait for them next time through linux_wait.  */

  if (!lwp->stopped)
    {
      if (debug_threads)
	fprintf (stderr,
		 "Need step over [LWP %ld]? Ignoring, not stopped\n",
		 lwpid_of (lwp));
      return 0;
    }

  thread = get_lwp_thread (lwp);

  if (thread->last_resume_kind == resume_stop)
    {
      if (debug_threads)
	fprintf (stderr,
		 "Need step over [LWP %ld]? Ignoring, should remain stopped\n",
		 lwpid_of (lwp));
      return 0;
    }

  gdb_assert (lwp->suspended >= 0);

  if (lwp->suspended)
    {
      if (debug_threads)
	fprintf (stderr,
		 "Need step over [LWP %ld]? Ignoring, suspended\n",
		 lwpid_of (lwp));
      return 0;
    }

  if (!lwp->need_step_over)
    {
      if (debug_threads)
	fprintf (stderr,
		 "Need step over [LWP %ld]? No\n", lwpid_of (lwp));
    }

  if (lwp->status_pending_p)
    {
      if (debug_threads)
	fprintf (stderr,
		 "Need step over [LWP %ld]? Ignoring, has pending status.\n",
		 lwpid_of (lwp));
      return 0;
    }

  /* Note: PC, not STOP_PC.  Either GDB has adjusted the PC already,
     or we have.  */
  pc = get_pc (lwp);

  /* If the PC has changed since we stopped, then don't do anything,
     and let the breakpoint/tracepoint be hit.  This happens if, for
     instance, GDB handled the decr_pc_after_break subtraction itself,
     GDB is OOL stepping this thread, or the user has issued a "jump"
     command, or poked thread's registers herself.  */
  if (pc != lwp->stop_pc)
    {
      if (debug_threads)
	fprintf (stderr,
		 "Need step over [LWP %ld]? Cancelling, PC was changed.  "
		 "Old stop_pc was 0x%s, PC is now 0x%s\n",
		 lwpid_of (lwp), paddress (lwp->stop_pc), paddress (pc));

      lwp->need_step_over = 0;
      return 0;
    }

  saved_inferior = current_inferior;
  current_inferior = thread;

  /* We can only step over breakpoints we know about.  */
  if (breakpoint_here (pc) || fast_tracepoint_jump_here (pc))
    {
      /* Don't step over a breakpoint that GDB expects to hit
	 though.  */
      if (gdb_breakpoint_here (pc))
	{
	  if (debug_threads)
	    fprintf (stderr,
		     "Need step over [LWP %ld]? yes, but found"
		     " GDB breakpoint at 0x%s; skipping step over\n",
		     lwpid_of (lwp), paddress (pc));

	  current_inferior = saved_inferior;
	  return 0;
	}
      else
	{
	  if (debug_threads)
	    fprintf (stderr,
		     "Need step over [LWP %ld]? yes, found breakpoint at 0x%s\n",
		     lwpid_of (lwp), paddress (pc));

	  /* We've found an lwp that needs stepping over --- return 1 so
	     that find_inferior stops looking.  */
	  current_inferior = saved_inferior;

	  /* If the step over is cancelled, this is set again.  */
	  lwp->need_step_over = 0;
	  return 1;
	}
    }

  current_inferior = saved_inferior;

  if (debug_threads)
    fprintf (stderr,
	     "Need step over [LWP %ld]? No, no breakpoint found at 0x%s\n",
	     lwpid_of (lwp), paddress (pc));

  return 0;
}

/* Start a step-over operation on LWP.  When LWP stopped at a
   breakpoint, to make progress, we need to remove the breakpoint out
   of the way.  If we let other threads run while we do that, they may
   pass by the breakpoint location and miss hitting it.  To avoid
   that, a step-over momentarily stops all threads while LWP is
   single-stepped while the breakpoint is temporarily uninserted from
   the inferior.  When the single-step finishes, we reinsert the
   breakpoint, and let all threads that are supposed to be running,
   run again.

   On targets that don't support hardware single-step, we don't
   currently support full software single-stepping.  Instead, we only
   support stepping over the thread event breakpoint, by asking the
   low target where to place a reinsert breakpoint.  Since this
   routine assumes the breakpoint being stepped over is a thread event
   breakpoint, it usually assumes the return address of the current
   function is a good enough place to set the reinsert breakpoint.  */

static int
start_step_over (struct lwp_info *lwp)
{
  struct thread_info *saved_inferior;
  CORE_ADDR pc;
  int step;

  if (debug_threads)
    fprintf (stderr,
	     "Starting step-over on LWP %ld.  Stopping all threads\n",
	     lwpid_of (lwp));

  stop_all_lwps (1, lwp);
  gdb_assert (lwp->suspended == 0);

  if (debug_threads)
    fprintf (stderr, "Done stopping all threads for step-over.\n");

  /* Note, we should always reach here with an already adjusted PC,
     either by GDB (if we're resuming due to GDB's request), or by our
     caller, if we just finished handling an internal breakpoint GDB
     shouldn't care about.  */
  pc = get_pc (lwp);

  saved_inferior = current_inferior;
  current_inferior = get_lwp_thread (lwp);

  lwp->bp_reinsert = pc;
  uninsert_breakpoints_at (pc);
  uninsert_fast_tracepoint_jumps_at (pc);

  if (can_hardware_single_step ())
    {
      step = 1;
    }
  else
    {
      CORE_ADDR raddr = (*the_low_target.breakpoint_reinsert_addr) ();
      set_reinsert_breakpoint (raddr);
      step = 0;
    }

  current_inferior = saved_inferior;

  linux_resume_one_lwp (lwp, step, 0, NULL);

  /* Require next event from this LWP.  */
  step_over_bkpt = lwp->head.id;
  return 1;
}

/* Finish a step-over.  Reinsert the breakpoint we had uninserted in
   start_step_over, if still there, and delete any reinsert
   breakpoints we've set, on non hardware single-step targets.  */

static int
finish_step_over (struct lwp_info *lwp)
{
  if (lwp->bp_reinsert != 0)
    {
      if (debug_threads)
	fprintf (stderr, "Finished step over.\n");

      /* Reinsert any breakpoint at LWP->BP_REINSERT.  Note that there
	 may be no breakpoint to reinsert there by now.  */
      reinsert_breakpoints_at (lwp->bp_reinsert);
      reinsert_fast_tracepoint_jumps_at (lwp->bp_reinsert);

      lwp->bp_reinsert = 0;

      /* Delete any software-single-step reinsert breakpoints.  No
	 longer needed.  We don't have to worry about other threads
	 hitting this trap, and later not being able to explain it,
	 because we were stepping over a breakpoint, and we hold all
	 threads but LWP stopped while doing that.  */
      if (!can_hardware_single_step ())
	delete_reinsert_breakpoints ();

      step_over_bkpt = null_ptid;
      return 1;
    }
  else
    return 0;
}

/* This function is called once per thread.  We check the thread's resume
   request, which will tell us whether to resume, step, or leave the thread
   stopped; and what signal, if any, it should be sent.

   For threads which we aren't explicitly told otherwise, we preserve
   the stepping flag; this is used for stepping over gdbserver-placed
   breakpoints.

   If pending_flags was set in any thread, we queue any needed
   signals, since we won't actually resume.  We already have a pending
   event to report, so we don't need to preserve any step requests;
   they should be re-issued if necessary.  */

static int
linux_resume_one_thread (struct inferior_list_entry *entry, void *arg)
{
  struct lwp_info *lwp;
  struct thread_info *thread;
  int step;
  int leave_all_stopped = * (int *) arg;
  int leave_pending;

  thread = (struct thread_info *) entry;
  lwp = get_thread_lwp (thread);

  if (lwp->resume == NULL)
    return 0;

  if (lwp->resume->kind == resume_stop)
    {
      if (debug_threads)
	fprintf (stderr, "resume_stop request for LWP %ld\n", lwpid_of (lwp));

      if (!lwp->stopped)
	{
	  if (debug_threads)
	    fprintf (stderr, "stopping LWP %ld\n", lwpid_of (lwp));

	  /* Stop the thread, and wait for the event asynchronously,
	     through the event loop.  */
	  send_sigstop (lwp);
	}
      else
	{
	  if (debug_threads)
	    fprintf (stderr, "already stopped LWP %ld\n",
		     lwpid_of (lwp));

	  /* The LWP may have been stopped in an internal event that
	     was not meant to be notified back to GDB (e.g., gdbserver
	     breakpoint), so we should be reporting a stop event in
	     this case too.  */

	  /* If the thread already has a pending SIGSTOP, this is a
	     no-op.  Otherwise, something later will presumably resume
	     the thread and this will cause it to cancel any pending
	     operation, due to last_resume_kind == resume_stop.  If
	     the thread already has a pending status to report, we
	     will still report it the next time we wait - see
	     status_pending_p_callback.  */
	  send_sigstop (lwp);
	}

      /* For stop requests, we're done.  */
      lwp->resume = NULL;
      thread->last_status.kind = TARGET_WAITKIND_IGNORE;
      return 0;
    }

  /* If this thread which is about to be resumed has a pending status,
     then don't resume any threads - we can just report the pending
     status.  Make sure to queue any signals that would otherwise be
     sent.  In all-stop mode, we do this decision based on if *any*
     thread has a pending status.  If there's a thread that needs the
     step-over-breakpoint dance, then don't resume any other thread
     but that particular one.  */
  leave_pending = (lwp->status_pending_p || leave_all_stopped);

  if (!leave_pending)
    {
      if (debug_threads)
	fprintf (stderr, "resuming LWP %ld\n", lwpid_of (lwp));

      step = (lwp->resume->kind == resume_step);
      linux_resume_one_lwp (lwp, step, lwp->resume->sig, NULL);
    }
  else
    {
      if (debug_threads)
	fprintf (stderr, "leaving LWP %ld stopped\n", lwpid_of (lwp));

      /* If we have a new signal, enqueue the signal.  */
      if (lwp->resume->sig != 0)
	{
	  struct pending_signals *p_sig;
	  p_sig = xmalloc (sizeof (*p_sig));
	  p_sig->prev = lwp->pending_signals;
	  p_sig->signal = lwp->resume->sig;
	  memset (&p_sig->info, 0, sizeof (siginfo_t));

	  /* If this is the same signal we were previously stopped by,
	     make sure to queue its siginfo.  We can ignore the return
	     value of ptrace; if it fails, we'll skip
	     PTRACE_SETSIGINFO.  */
	  if (WIFSTOPPED (lwp->last_status)
	      && WSTOPSIG (lwp->last_status) == lwp->resume->sig)
	    ptrace (PTRACE_GETSIGINFO, lwpid_of (lwp), 0, &p_sig->info);

	  lwp->pending_signals = p_sig;
	}
    }

  thread->last_status.kind = TARGET_WAITKIND_IGNORE;
  lwp->resume = NULL;
  return 0;
}

static void
linux_resume (struct thread_resume *resume_info, size_t n)
{
  struct thread_resume_array array = { resume_info, n };
  struct lwp_info *need_step_over = NULL;
  int any_pending;
  int leave_all_stopped;

  find_inferior (&all_threads, linux_set_resume_request, &array);

  /* If there is a thread which would otherwise be resumed, which has
     a pending status, then don't resume any threads - we can just
     report the pending status.  Make sure to queue any signals that
     would otherwise be sent.  In non-stop mode, we'll apply this
     logic to each thread individually.  We consume all pending events
     before considering to start a step-over (in all-stop).  */
  any_pending = 0;
  if (!non_stop)
    find_inferior (&all_lwps, resume_status_pending_p, &any_pending);

  /* If there is a thread which would otherwise be resumed, which is
     stopped at a breakpoint that needs stepping over, then don't
     resume any threads - have it step over the breakpoint with all
     other threads stopped, then resume all threads again.  Make sure
     to queue any signals that would otherwise be delivered or
     queued.  */
  if (!any_pending && supports_breakpoints ())
    need_step_over
      = (struct lwp_info *) find_inferior (&all_lwps,
					   need_step_over_p, NULL);

  leave_all_stopped = (need_step_over != NULL || any_pending);

  if (debug_threads)
    {
      if (need_step_over != NULL)
	fprintf (stderr, "Not resuming all, need step over\n");
      else if (any_pending)
	fprintf (stderr,
		 "Not resuming, all-stop and found "
		 "an LWP with pending status\n");
      else
	fprintf (stderr, "Resuming, no pending status or step over needed\n");
    }

  /* Even if we're leaving threads stopped, queue all signals we'd
     otherwise deliver.  */
  find_inferior (&all_threads, linux_resume_one_thread, &leave_all_stopped);

  if (need_step_over)
    start_step_over (need_step_over);
}

/* This function is called once per thread.  We check the thread's
   last resume request, which will tell us whether to resume, step, or
   leave the thread stopped.  Any signal the client requested to be
   delivered has already been enqueued at this point.

   If any thread that GDB wants running is stopped at an internal
   breakpoint that needs stepping over, we start a step-over operation
   on that particular thread, and leave all others stopped.  */

static int
proceed_one_lwp (struct inferior_list_entry *entry, void *except)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;
  struct thread_info *thread;
  int step;

  if (lwp == except)
    return 0;

  if (debug_threads)
    fprintf (stderr,
	     "proceed_one_lwp: lwp %ld\n", lwpid_of (lwp));

  if (!lwp->stopped)
    {
      if (debug_threads)
	fprintf (stderr, "   LWP %ld already running\n", lwpid_of (lwp));
      return 0;
    }

  thread = get_lwp_thread (lwp);

  if (thread->last_resume_kind == resume_stop
      && thread->last_status.kind != TARGET_WAITKIND_IGNORE)
    {
      if (debug_threads)
	fprintf (stderr, "   client wants LWP to remain %ld stopped\n",
		 lwpid_of (lwp));
      return 0;
    }

  if (lwp->status_pending_p)
    {
      if (debug_threads)
	fprintf (stderr, "   LWP %ld has pending status, leaving stopped\n",
		 lwpid_of (lwp));
      return 0;
    }

  gdb_assert (lwp->suspended >= 0);

  if (lwp->suspended)
    {
      if (debug_threads)
	fprintf (stderr, "   LWP %ld is suspended\n", lwpid_of (lwp));
      return 0;
    }

  if (thread->last_resume_kind == resume_stop)
    {
      /* We haven't reported this LWP as stopped yet (otherwise, the
	 last_status.kind check above would catch it, and we wouldn't
	 reach here.  This LWP may have been momentarily paused by a
	 stop_all_lwps call while handling for example, another LWP's
	 step-over.  In that case, the pending expected SIGSTOP signal
	 that was queued at vCont;t handling time will have already
	 been consumed by wait_for_sigstop, and so we need to requeue
	 another one here.  Note that if the LWP already has a SIGSTOP
	 pending, this is a no-op.  */

      if (debug_threads)
	fprintf (stderr,
		 "Client wants LWP %ld to stop. "
		 "Making sure it has a SIGSTOP pending\n",
		 lwpid_of (lwp));

      send_sigstop (lwp);
    }

  step = thread->last_resume_kind == resume_step;
  linux_resume_one_lwp (lwp, step, 0, NULL);
  return 0;
}

static int
unsuspend_and_proceed_one_lwp (struct inferior_list_entry *entry, void *except)
{
  struct lwp_info *lwp = (struct lwp_info *) entry;

  if (lwp == except)
    return 0;

  lwp->suspended--;
  gdb_assert (lwp->suspended >= 0);

  return proceed_one_lwp (entry, except);
}

/* When we finish a step-over, set threads running again.  If there's
   another thread that may need a step-over, now's the time to start
   it.  Eventually, we'll move all threads past their breakpoints.  */

static void
proceed_all_lwps (void)
{
  struct lwp_info *need_step_over;

  /* If there is a thread which would otherwise be resumed, which is
     stopped at a breakpoint that needs stepping over, then don't
     resume any threads - have it step over the breakpoint with all
     other threads stopped, then resume all threads again.  */

  if (supports_breakpoints ())
    {
      need_step_over
	= (struct lwp_info *) find_inferior (&all_lwps,
					     need_step_over_p, NULL);

      if (need_step_over != NULL)
	{
	  if (debug_threads)
	    fprintf (stderr, "proceed_all_lwps: found "
		     "thread %ld needing a step-over\n",
		     lwpid_of (need_step_over));

	  start_step_over (need_step_over);
	  return;
	}
    }

  if (debug_threads)
    fprintf (stderr, "Proceeding, no step-over needed\n");

  find_inferior (&all_lwps, proceed_one_lwp, NULL);
}

/* Stopped LWPs that the client wanted to be running, that don't have
   pending statuses, are set to run again, except for EXCEPT, if not
   NULL.  This undoes a stop_all_lwps call.  */

static void
unstop_all_lwps (int unsuspend, struct lwp_info *except)
{
  if (debug_threads)
    {
      if (except)
	fprintf (stderr,
		 "unstopping all lwps, except=(LWP %ld)\n", lwpid_of (except));
      else
	fprintf (stderr,
		 "unstopping all lwps\n");
    }

  if (unsuspend)
    find_inferior (&all_lwps, unsuspend_and_proceed_one_lwp, except);
  else
    find_inferior (&all_lwps, proceed_one_lwp, except);
}

#ifdef HAVE_LINUX_USRREGS

int
register_addr (int regnum)
{
  int addr;

  if (regnum < 0 || regnum >= the_low_target.num_regs)
    error ("Invalid register number %d.", regnum);

  addr = the_low_target.regmap[regnum];

  return addr;
}

/* Fetch one register.  */
static void
fetch_register (struct regcache *regcache, int regno)
{
  CORE_ADDR regaddr;
  int i, size;
  char *buf;
  int pid;

  if (regno >= the_low_target.num_regs)
    return;
  if ((*the_low_target.cannot_fetch_register) (regno))
    return;

  regaddr = register_addr (regno);
  if (regaddr == -1)
    return;

  pid = lwpid_of (get_thread_lwp (current_inferior));
  size = ((register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1)
	  & - sizeof (PTRACE_XFER_TYPE));
  buf = alloca (size);
  for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE))
    {
      errno = 0;
      *(PTRACE_XFER_TYPE *) (buf + i) =
	ptrace (PTRACE_PEEKUSER, pid,
		/* Coerce to a uintptr_t first to avoid potential gcc warning
		   of coercing an 8 byte integer to a 4 byte pointer.  */
		(PTRACE_ARG3_TYPE) (uintptr_t) regaddr, 0);
      regaddr += sizeof (PTRACE_XFER_TYPE);
      if (errno != 0)
	error ("reading register %d: %s", regno, strerror (errno));
    }

  if (the_low_target.supply_ptrace_register)
    the_low_target.supply_ptrace_register (regcache, regno, buf);
  else
    supply_register (regcache, regno, buf);
}

/* Fetch all registers, or just one, from the child process.  */
static void
usr_fetch_inferior_registers (struct regcache *regcache, int regno)
{
  if (regno == -1)
    for (regno = 0; regno < the_low_target.num_regs; regno++)
      fetch_register (regcache, regno);
  else
    fetch_register (regcache, regno);
}

/* Store our register values back into the inferior.
   If REGNO is -1, do this for all registers.
   Otherwise, REGNO specifies which register (so we can save time).  */
static void
usr_store_inferior_registers (struct regcache *regcache, int regno)
{
  CORE_ADDR regaddr;
  int i, size;
  char *buf;
  int pid;

  if (regno >= 0)
    {
      if (regno >= the_low_target.num_regs)
	return;

      if ((*the_low_target.cannot_store_register) (regno) == 1)
	return;

      regaddr = register_addr (regno);
      if (regaddr == -1)
	return;
      errno = 0;
      size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1)
	     & - sizeof (PTRACE_XFER_TYPE);
      buf = alloca (size);
      memset (buf, 0, size);

      if (the_low_target.collect_ptrace_register)
	the_low_target.collect_ptrace_register (regcache, regno, buf);
      else
	collect_register (regcache, regno, buf);

      pid = lwpid_of (get_thread_lwp (current_inferior));
      for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE))
	{
	  errno = 0;
	  ptrace (PTRACE_POKEUSER, pid,
		/* Coerce to a uintptr_t first to avoid potential gcc warning
		   about coercing an 8 byte integer to a 4 byte pointer.  */
		  (PTRACE_ARG3_TYPE) (uintptr_t) regaddr,
		  (PTRACE_ARG4_TYPE) *(PTRACE_XFER_TYPE *) (buf + i));
	  if (errno != 0)
	    {
	      /* At this point, ESRCH should mean the process is
		 already gone, in which case we simply ignore attempts
		 to change its registers.  See also the related
		 comment in linux_resume_one_lwp.  */
	      if (errno == ESRCH)
		return;

	      if ((*the_low_target.cannot_store_register) (regno) == 0)
		error ("writing register %d: %s", regno, strerror (errno));
	    }
	  regaddr += sizeof (PTRACE_XFER_TYPE);
	}
    }
  else
    for (regno = 0; regno < the_low_target.num_regs; regno++)
      usr_store_inferior_registers (regcache, regno);
}
#endif /* HAVE_LINUX_USRREGS */



#ifdef HAVE_LINUX_REGSETS

static int
regsets_fetch_inferior_registers (struct regcache *regcache)
{
  struct regset_info *regset;
  int saw_general_regs = 0;
  int pid;
  struct iovec iov;

  regset = target_regsets;

  pid = lwpid_of (get_thread_lwp (current_inferior));
  while (regset->size >= 0)
    {
      void *buf, *data;
      int nt_type, res;

      if (regset->size == 0 || disabled_regsets[regset - target_regsets])
	{
	  regset ++;
	  continue;
	}

      buf = xmalloc (regset->size);

      nt_type = regset->nt_type;
      if (nt_type)
	{
	  iov.iov_base = buf;
	  iov.iov_len = regset->size;
	  data = (void *) &iov;
	}
      else
	data = buf;

#ifndef __sparc__
      res = ptrace (regset->get_request, pid, nt_type, data);
#else
      res = ptrace (regset->get_request, pid, data, nt_type);
#endif
      if (res < 0)
	{
	  if (errno == EIO)
	    {
	      /* If we get EIO on a regset, do not try it again for
		 this process.  */
	      disabled_regsets[regset - target_regsets] = 1;
	      free (buf);
	      continue;
	    }
	  else
	    {
	      char s[256];
	      sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%d",
		       pid);
	      perror (s);
	    }
	}
      else if (regset->type == GENERAL_REGS)
	saw_general_regs = 1;
      regset->store_function (regcache, buf);
      regset ++;
      free (buf);
    }
  if (saw_general_regs)
    return 0;
  else
    return 1;
}

static int
regsets_store_inferior_registers (struct regcache *regcache)
{
  struct regset_info *regset;
  int saw_general_regs = 0;
  int pid;
  struct iovec iov;

  regset = target_regsets;

  pid = lwpid_of (get_thread_lwp (current_inferior));
  while (regset->size >= 0)
    {
      void *buf, *data;
      int nt_type, res;

      if (regset->size == 0 || disabled_regsets[regset - target_regsets])
	{
	  regset ++;
	  continue;
	}

      buf = xmalloc (regset->size);

      /* First fill the buffer with the current register set contents,
	 in case there are any items in the kernel's regset that are
	 not in gdbserver's regcache.  */

      nt_type = regset->nt_type;
      if (nt_type)
	{
	  iov.iov_base = buf;
	  iov.iov_len = regset->size;
	  data = (void *) &iov;
	}
      else
	data = buf;

#ifndef __sparc__
      res = ptrace (regset->get_request, pid, nt_type, data);
#else
      res = ptrace (regset->get_request, pid, &iov, data);
#endif

      if (res == 0)
	{
	  /* Then overlay our cached registers on that.  */
	  regset->fill_function (regcache, buf);

	  /* Only now do we write the register set.  */
#ifndef __sparc__
	  res = ptrace (regset->set_request, pid, nt_type, data);
#else
	  res = ptrace (regset->set_request, pid, data, nt_type);
#endif
	}

      if (res < 0)
	{
	  if (errno == EIO)
	    {
	      /* If we get EIO on a regset, do not try it again for
		 this process.  */
	      disabled_regsets[regset - target_regsets] = 1;
	      free (buf);
	      continue;
	    }
	  else if (errno == ESRCH)
	    {
	      /* At this point, ESRCH should mean the process is
		 already gone, in which case we simply ignore attempts
		 to change its registers.  See also the related
		 comment in linux_resume_one_lwp.  */
	      free (buf);
	      return 0;
	    }
	  else
	    {
	      perror ("Warning: ptrace(regsets_store_inferior_registers)");
	    }
	}
      else if (regset->type == GENERAL_REGS)
	saw_general_regs = 1;
      regset ++;
      free (buf);
    }
  if (saw_general_regs)
    return 0;
  else
    return 1;
  return 0;
}

#endif /* HAVE_LINUX_REGSETS */


void
linux_fetch_registers (struct regcache *regcache, int regno)
{
#ifdef HAVE_LINUX_REGSETS
  if (regsets_fetch_inferior_registers (regcache) == 0)
    return;
#endif
#ifdef HAVE_LINUX_USRREGS
  usr_fetch_inferior_registers (regcache, regno);
#endif
}

void
linux_store_registers (struct regcache *regcache, int regno)
{
#ifdef HAVE_LINUX_REGSETS
  if (regsets_store_inferior_registers (regcache) == 0)
    return;
#endif
#ifdef HAVE_LINUX_USRREGS
  usr_store_inferior_registers (regcache, regno);
#endif
}


/* Copy LEN bytes from inferior's memory starting at MEMADDR
   to debugger memory starting at MYADDR.  */

static int
linux_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
{
  register int i;
  /* Round starting address down to longword boundary.  */
  register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
  /* Round ending address up; get number of longwords that makes.  */
  register int count
    = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
      / sizeof (PTRACE_XFER_TYPE);
  /* Allocate buffer of that many longwords.  */
  register PTRACE_XFER_TYPE *buffer
    = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
  int fd;
  char filename[64];
  int pid = lwpid_of (get_thread_lwp (current_inferior));

  /* Try using /proc.  Don't bother for one word.  */
  if (len >= 3 * sizeof (long))
    {
      /* We could keep this file open and cache it - possibly one per
	 thread.  That requires some juggling, but is even faster.  */
      sprintf (filename, "/proc/%d/mem", pid);
      fd = open (filename, O_RDONLY | O_LARGEFILE);
      if (fd == -1)
	goto no_proc;

      /* If pread64 is available, use it.  It's faster if the kernel
	 supports it (only one syscall), and it's 64-bit safe even on
	 32-bit platforms (for instance, SPARC debugging a SPARC64
	 application).  */
#ifdef HAVE_PREAD64
      if (pread64 (fd, myaddr, len, memaddr) != len)
#else
      if (lseek (fd, memaddr, SEEK_SET) == -1 || read (fd, myaddr, len) != len)
#endif
	{
	  close (fd);
	  goto no_proc;
	}

      close (fd);
      return 0;
    }

 no_proc:
  /* Read all the longwords */
  for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
    {
      errno = 0;
      /* Coerce the 3rd arg to a uintptr_t first to avoid potential gcc warning
	 about coercing an 8 byte integer to a 4 byte pointer.  */
      buffer[i] = ptrace (PTRACE_PEEKTEXT, pid,
			  (PTRACE_ARG3_TYPE) (uintptr_t) addr, 0);
      if (errno)
	return errno;
    }

  /* Copy appropriate bytes out of the buffer.  */
  memcpy (myaddr,
	  (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)),
	  len);

  return 0;
}

/* Copy LEN bytes of data from debugger memory at MYADDR to inferior's
   memory at MEMADDR.  On failure (cannot write to the inferior)
   returns the value of errno.  */

static int
linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
{
  register int i;
  /* Round starting address down to longword boundary.  */
  register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
  /* Round ending address up; get number of longwords that makes.  */
  register int count
  = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE);
  /* Allocate buffer of that many longwords.  */
  register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
  int pid = lwpid_of (get_thread_lwp (current_inferior));

  if (debug_threads)
    {
      /* Dump up to four bytes.  */
      unsigned int val = * (unsigned int *) myaddr;
      if (len == 1)
	val = val & 0xff;
      else if (len == 2)
	val = val & 0xffff;
      else if (len == 3)
	val = val & 0xffffff;
      fprintf (stderr, "Writing %0*x to 0x%08lx\n", 2 * ((len < 4) ? len : 4),
	       val, (long)memaddr);
    }

  /* Fill start and end extra bytes of buffer with existing memory data.  */

  errno = 0;
  /* Coerce the 3rd arg to a uintptr_t first to avoid potential gcc warning
     about coercing an 8 byte integer to a 4 byte pointer.  */
  buffer[0] = ptrace (PTRACE_PEEKTEXT, pid,
		      (PTRACE_ARG3_TYPE) (uintptr_t) addr, 0);
  if (errno)
    return errno;

  if (count > 1)
    {
      errno = 0;
      buffer[count - 1]
	= ptrace (PTRACE_PEEKTEXT, pid,
		  /* Coerce to a uintptr_t first to avoid potential gcc warning
		     about coercing an 8 byte integer to a 4 byte pointer.  */
		  (PTRACE_ARG3_TYPE) (uintptr_t) (addr + (count - 1)
						  * sizeof (PTRACE_XFER_TYPE)),
		  0);
      if (errno)
	return errno;
    }

  /* Copy data to be written over corresponding part of buffer.  */

  memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), myaddr, len);

  /* Write the entire buffer.  */

  for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
    {
      errno = 0;
      ptrace (PTRACE_POKETEXT, pid,
	      /* Coerce to a uintptr_t first to avoid potential gcc warning
		 about coercing an 8 byte integer to a 4 byte pointer.  */
	      (PTRACE_ARG3_TYPE) (uintptr_t) addr,
	      (PTRACE_ARG4_TYPE) buffer[i]);
      if (errno)
	return errno;
    }

  return 0;
}

/* Non-zero if the kernel supports PTRACE_O_TRACEFORK.  */
static int linux_supports_tracefork_flag;

static void
linux_enable_event_reporting (int pid)
{
  if (!linux_supports_tracefork_flag)
    return;

  ptrace (PTRACE_SETOPTIONS, pid, 0, (PTRACE_ARG4_TYPE) PTRACE_O_TRACECLONE);
}

/* Helper functions for linux_test_for_tracefork, called via clone ().  */

static int
linux_tracefork_grandchild (void *arg)
{
  _exit (0);
}

#define STACK_SIZE 4096

static int
linux_tracefork_child (void *arg)
{
  ptrace (PTRACE_TRACEME, 0, 0, 0);
  kill (getpid (), SIGSTOP);

#if !(defined(__UCLIBC__) && defined(HAS_NOMMU))

  if (fork () == 0)
    linux_tracefork_grandchild (NULL);

#else /* defined(__UCLIBC__) && defined(HAS_NOMMU) */

#ifdef __ia64__
  __clone2 (linux_tracefork_grandchild, arg, STACK_SIZE,
	    CLONE_VM | SIGCHLD, NULL);
#else
  clone (linux_tracefork_grandchild, arg + STACK_SIZE,
	 CLONE_VM | SIGCHLD, NULL);
#endif

#endif /* defined(__UCLIBC__) && defined(HAS_NOMMU) */

  _exit (0);
}

/* Determine if PTRACE_O_TRACEFORK can be used to follow fork events.  Make
   sure that we can enable the option, and that it had the desired
   effect.  */

static void
linux_test_for_tracefork (void)
{
  int child_pid, ret, status;
  long second_pid;
#if defined(__UCLIBC__) && defined(HAS_NOMMU)
  char *stack = xmalloc (STACK_SIZE * 4);
#endif /* defined(__UCLIBC__) && defined(HAS_NOMMU) */

  linux_supports_tracefork_flag = 0;

#if !(defined(__UCLIBC__) && defined(HAS_NOMMU))

  child_pid = fork ();
  if (child_pid == 0)
    linux_tracefork_child (NULL);

#else /* defined(__UCLIBC__) && defined(HAS_NOMMU) */

  /* Use CLONE_VM instead of fork, to support uClinux (no MMU).  */
#ifdef __ia64__
  child_pid = __clone2 (linux_tracefork_child, stack, STACK_SIZE,
			CLONE_VM | SIGCHLD, stack + STACK_SIZE * 2);
#else /* !__ia64__ */
  child_pid = clone (linux_tracefork_child, stack + STACK_SIZE,
		     CLONE_VM | SIGCHLD, stack + STACK_SIZE * 2);
#endif /* !__ia64__ */

#endif /* defined(__UCLIBC__) && defined(HAS_NOMMU) */

  if (child_pid == -1)
    perror_with_name ("clone");

  ret = my_waitpid (child_pid, &status, 0);
  if (ret == -1)
    perror_with_name ("waitpid");
  else if (ret != child_pid)
    error ("linux_test_for_tracefork: waitpid: unexpected result %d.", ret);
  if (! WIFSTOPPED (status))
    error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status);

  ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0,
		(PTRACE_ARG4_TYPE) PTRACE_O_TRACEFORK);
  if (ret != 0)
    {
      ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
      if (ret != 0)
	{
	  warning ("linux_test_for_tracefork: failed to kill child");
	  return;
	}

      ret = my_waitpid (child_pid, &status, 0);
      if (ret != child_pid)
	warning ("linux_test_for_tracefork: failed to wait for killed child");
      else if (!WIFSIGNALED (status))
	warning ("linux_test_for_tracefork: unexpected wait status 0x%x from "
		 "killed child", status);

      return;
    }

  ret = ptrace (PTRACE_CONT, child_pid, 0, 0);
  if (ret != 0)
    warning ("linux_test_for_tracefork: failed to resume child");

  ret = my_waitpid (child_pid, &status, 0);

  if (ret == child_pid && WIFSTOPPED (status)
      && status >> 16 == PTRACE_EVENT_FORK)
    {
      second_pid = 0;
      ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid);
      if (ret == 0 && second_pid != 0)
	{
	  int second_status;

	  linux_supports_tracefork_flag = 1;
	  my_waitpid (second_pid, &second_status, 0);
	  ret = ptrace (PTRACE_KILL, second_pid, 0, 0);
	  if (ret != 0)
	    warning ("linux_test_for_tracefork: failed to kill second child");
	  my_waitpid (second_pid, &status, 0);
	}
    }
  else
    warning ("linux_test_for_tracefork: unexpected result from waitpid "
	     "(%d, status 0x%x)", ret, status);

  do
    {
      ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
      if (ret != 0)
	warning ("linux_test_for_tracefork: failed to kill child");
      my_waitpid (child_pid, &status, 0);
    }
  while (WIFSTOPPED (status));

#if defined(__UCLIBC__) && defined(HAS_NOMMU)
  free (stack);
#endif /* defined(__UCLIBC__) && defined(HAS_NOMMU) */
}


static void
linux_look_up_symbols (void)
{
#ifdef USE_THREAD_DB
  struct process_info *proc = current_process ();

  if (proc->private->thread_db != NULL)
    return;

  /* If the kernel supports tracing forks then it also supports tracing
     clones, and then we don't need to use the magic thread event breakpoint
     to learn about threads.  */
  thread_db_init (!linux_supports_tracefork_flag);
#endif
}

static void
linux_request_interrupt (void)
{
  extern unsigned long signal_pid;

  if (!ptid_equal (cont_thread, null_ptid)
      && !ptid_equal (cont_thread, minus_one_ptid))
    {
      struct lwp_info *lwp;
      int lwpid;

      lwp = get_thread_lwp (current_inferior);
      lwpid = lwpid_of (lwp);
      kill_lwp (lwpid, SIGINT);
    }
  else
    kill_lwp (signal_pid, SIGINT);
}

/* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET
   to debugger memory starting at MYADDR.  */

static int
linux_read_auxv (CORE_ADDR offset, unsigned char *myaddr, unsigned int len)
{
  char filename[PATH_MAX];
  int fd, n;
  int pid = lwpid_of (get_thread_lwp (current_inferior));

  snprintf (filename, sizeof filename, "/proc/%d/auxv", pid);

  fd = open (filename, O_RDONLY);
  if (fd < 0)
    return -1;

  if (offset != (CORE_ADDR) 0
      && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
    n = -1;
  else
    n = read (fd, myaddr, len);

  close (fd);

  return n;
}

/* These breakpoint and watchpoint related wrapper functions simply
   pass on the function call if the target has registered a
   corresponding function.  */

static int
linux_insert_point (char type, CORE_ADDR addr, int len)
{
  if (the_low_target.insert_point != NULL)
    return the_low_target.insert_point (type, addr, len);
  else
    /* Unsupported (see target.h).  */
    return 1;
}

static int
linux_remove_point (char type, CORE_ADDR addr, int len)
{
  if (the_low_target.remove_point != NULL)
    return the_low_target.remove_point (type, addr, len);
  else
    /* Unsupported (see target.h).  */
    return 1;
}

static int
linux_stopped_by_watchpoint (void)
{
  struct lwp_info *lwp = get_thread_lwp (current_inferior);

  return lwp->stopped_by_watchpoint;
}

static CORE_ADDR
linux_stopped_data_address (void)
{
  struct lwp_info *lwp = get_thread_lwp (current_inferior);

  return lwp->stopped_data_address;
}

#if defined(__UCLIBC__) && defined(HAS_NOMMU)
#if defined(__mcoldfire__)
/* These should really be defined in the kernel's ptrace.h header.  */
#define PT_TEXT_ADDR 49*4
#define PT_DATA_ADDR 50*4
#define PT_TEXT_END_ADDR  51*4
#endif

/* Under uClinux, programs are loaded at non-zero offsets, which we need
   to tell gdb about.  */

static int
linux_read_offsets (CORE_ADDR *text_p, CORE_ADDR *data_p)
{
#if defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) && defined(PT_TEXT_END_ADDR)
  unsigned long text, text_end, data;
  int pid = lwpid_of (get_thread_lwp (current_inferior));

  errno = 0;

  text = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_ADDR, 0);
  text_end = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_END_ADDR, 0);
  data = ptrace (PTRACE_PEEKUSER, pid, (long)PT_DATA_ADDR, 0);

  if (errno == 0)
    {
      /* Both text and data offsets produced at compile-time (and so
	 used by gdb) are relative to the beginning of the program,
	 with the data segment immediately following the text segment.
	 However, the actual runtime layout in memory may put the data
	 somewhere else, so when we send gdb a data base-address, we
	 use the real data base address and subtract the compile-time
	 data base-address from it (which is just the length of the
	 text segment).  BSS immediately follows data in both
	 cases.  */
      *text_p = text;
      *data_p = data - (text_end - text);

      return 1;
    }
#endif
 return 0;
}
#endif

static int
compare_ints (const void *xa, const void *xb)
{
  int a = *(const int *)xa;
  int b = *(const int *)xb;

  return a - b;
}

static int *
unique (int *b, int *e)
{
  int *d = b;
  while (++b != e)
    if (*d != *b)
      *++d = *b;
  return ++d;
}

/* Given PID, iterates over all threads in that process.

   Information about each thread, in a format suitable for qXfer:osdata:thread
   is printed to BUFFER, if it's not NULL.  BUFFER is assumed to be already
   initialized, and the caller is responsible for finishing and appending '\0'
   to it.

   The list of cores that threads are running on is assigned to *CORES, if it
   is not NULL.  If no cores are found, *CORES will be set to NULL.  Caller
   should free *CORES.  */

static void
list_threads (int pid, struct buffer *buffer, char **cores)
{
  int count = 0;
  int allocated = 10;
  int *core_numbers = xmalloc (sizeof (int) * allocated);
  char pathname[128];
  DIR *dir;
  struct dirent *dp;
  struct stat statbuf;

  sprintf (pathname, "/proc/%d/task", pid);
  if (stat (pathname, &statbuf) == 0 && S_ISDIR (statbuf.st_mode))
    {
      dir = opendir (pathname);
      if (!dir)
	{
	  free (core_numbers);
	  return;
	}

      while ((dp = readdir (dir)) != NULL)
	{
	  unsigned long lwp = strtoul (dp->d_name, NULL, 10);

	  if (lwp != 0)
	    {
	      unsigned core = linux_core_of_thread (ptid_build (pid, lwp, 0));

	      if (core != -1)
		{
		  char s[sizeof ("4294967295")];
		  sprintf (s, "%u", core);

		  if (count == allocated)
		    {
		      allocated *= 2;
		      core_numbers = realloc (core_numbers,
					      sizeof (int) * allocated);
		    }
		  core_numbers[count++] = core;
		  if (buffer)
		    buffer_xml_printf (buffer,
				       "<item>"
				       "<column name=\"pid\">%d</column>"
				       "<column name=\"tid\">%s</column>"
				       "<column name=\"core\">%s</column>"
				       "</item>", pid, dp->d_name, s);
		}
	      else
		{
		  if (buffer)
		    buffer_xml_printf (buffer,
				       "<item>"
				       "<column name=\"pid\">%d</column>"
				       "<column name=\"tid\">%s</column>"
				       "</item>", pid, dp->d_name);
		}
	    }
	}
    }

  if (cores)
    {
      *cores = NULL;
      if (count > 0)
	{
	  struct buffer buffer2;
	  int *b;
	  int *e;
	  qsort (core_numbers, count, sizeof (int), compare_ints);

	  /* Remove duplicates. */
	  b = core_numbers;
	  e = unique (b, core_numbers + count);

	  buffer_init (&buffer2);

	  for (b = core_numbers; b != e; ++b)
	    {
	      char number[sizeof ("4294967295")];
	      sprintf (number, "%u", *b);
	      buffer_xml_printf (&buffer2, "%s%s",
				 (b == core_numbers) ? "" : ",", number);
	    }
	  buffer_grow_str0 (&buffer2, "");

	  *cores = buffer_finish (&buffer2);
	}
    }
  free (core_numbers);
}

static void
show_process (int pid, const char *username, struct buffer *buffer)
{
  char pathname[128];
  FILE *f;
  char cmd[MAXPATHLEN + 1];

  sprintf (pathname, "/proc/%d/cmdline", pid);

  if ((f = fopen (pathname, "r")) != NULL)
    {
      size_t len = fread (cmd, 1, sizeof (cmd) - 1, f);
      if (len > 0)
	{
	  char *cores = 0;
	  int i;
	  for (i = 0; i < len; i++)
	    if (cmd[i] == '\0')
	      cmd[i] = ' ';
	  cmd[len] = '\0';

	  buffer_xml_printf (buffer,
			     "<item>"
			     "<column name=\"pid\">%d</column>"
			     "<column name=\"user\">%s</column>"
			     "<column name=\"command\">%s</column>",
			     pid,
			     username,
			     cmd);

	  /* This only collects core numbers, and does not print threads.  */
	  list_threads (pid, NULL, &cores);

	  if (cores)
	    {
	      buffer_xml_printf (buffer,
				 "<column name=\"cores\">%s</column>", cores);
	      free (cores);
	    }

	  buffer_xml_printf (buffer, "</item>");
	}
      fclose (f);
    }
}

static int
linux_qxfer_osdata (const char *annex,
		    unsigned char *readbuf, unsigned const char *writebuf,
		    CORE_ADDR offset, int len)
{
  /* We make the process list snapshot when the object starts to be
     read.  */
  static const char *buf;
  static long len_avail = -1;
  static struct buffer buffer;
  int processes = 0;
  int threads = 0;

  DIR *dirp;

  if (strcmp (annex, "processes") == 0)
    processes = 1;
  else if (strcmp (annex, "threads") == 0)
    threads = 1;
  else
    return 0;

  if (!readbuf || writebuf)
    return 0;

  if (offset == 0)
    {
      if (len_avail != -1 && len_avail != 0)
       buffer_free (&buffer);
      len_avail = 0;
      buf = NULL;
      buffer_init (&buffer);
      if (processes)
	buffer_grow_str (&buffer, "<osdata type=\"processes\">");
      else if (threads)
	buffer_grow_str (&buffer, "<osdata type=\"threads\">");

      dirp = opendir ("/proc");
      if (dirp)
       {
	 struct dirent *dp;
	 while ((dp = readdir (dirp)) != NULL)
	   {
	     struct stat statbuf;
	     char procentry[sizeof ("/proc/4294967295")];

	     if (!isdigit (dp->d_name[0])
		 || strlen (dp->d_name) > sizeof ("4294967295") - 1)
	       continue;

	     sprintf (procentry, "/proc/%s", dp->d_name);
	     if (stat (procentry, &statbuf) == 0
		 && S_ISDIR (statbuf.st_mode))
	       {
		 int pid = (int) strtoul (dp->d_name, NULL, 10);

		 if (processes)
		   {
		     struct passwd *entry = getpwuid (statbuf.st_uid);
		     show_process (pid, entry ? entry->pw_name : "?", &buffer);
		   }
		 else if (threads)
		   {
		     list_threads (pid, &buffer, NULL);
		   }
	       }
	   }

	 closedir (dirp);
       }
      buffer_grow_str0 (&buffer, "</osdata>\n");
      buf = buffer_finish (&buffer);
      len_avail = strlen (buf);
    }

  if (offset >= len_avail)
    {
      /* Done.  Get rid of the data.  */
      buffer_free (&buffer);
      buf = NULL;
      len_avail = 0;
      return 0;
    }

  if (len > len_avail - offset)
    len = len_avail - offset;
  memcpy (readbuf, buf + offset, len);

  return len;
}

/* Convert a native/host siginfo object, into/from the siginfo in the
   layout of the inferiors' architecture.  */

static void
siginfo_fixup (struct siginfo *siginfo, void *inf_siginfo, int direction)
{
  int done = 0;

  if (the_low_target.siginfo_fixup != NULL)
    done = the_low_target.siginfo_fixup (siginfo, inf_siginfo, direction);

  /* If there was no callback, or the callback didn't do anything,
     then just do a straight memcpy.  */
  if (!done)
    {
      if (direction == 1)
	memcpy (siginfo, inf_siginfo, sizeof (struct siginfo));
      else
	memcpy (inf_siginfo, siginfo, sizeof (struct siginfo));
    }
}

static int
linux_xfer_siginfo (const char *annex, unsigned char *readbuf,
		    unsigned const char *writebuf, CORE_ADDR offset, int len)
{
  int pid;
  struct siginfo siginfo;
  char inf_siginfo[sizeof (struct siginfo)];

  if (current_inferior == NULL)
    return -1;

  pid = lwpid_of (get_thread_lwp (current_inferior));

  if (debug_threads)
    fprintf (stderr, "%s siginfo for lwp %d.\n",
	     readbuf != NULL ? "Reading" : "Writing",
	     pid);

  if (offset > sizeof (siginfo))
    return -1;

  if (ptrace (PTRACE_GETSIGINFO, pid, 0, &siginfo) != 0)
    return -1;

  /* When GDBSERVER is built as a 64-bit application, ptrace writes into
     SIGINFO an object with 64-bit layout.  Since debugging a 32-bit
     inferior with a 64-bit GDBSERVER should look the same as debugging it
     with a 32-bit GDBSERVER, we need to convert it.  */
  siginfo_fixup (&siginfo, inf_siginfo, 0);

  if (offset + len > sizeof (siginfo))
    len = sizeof (siginfo) - offset;

  if (readbuf != NULL)
    memcpy (readbuf, inf_siginfo + offset, len);
  else
    {
      memcpy (inf_siginfo + offset, writebuf, len);

      /* Convert back to ptrace layout before flushing it out.  */
      siginfo_fixup (&siginfo, inf_siginfo, 1);

      if (ptrace (PTRACE_SETSIGINFO, pid, 0, &siginfo) != 0)
	return -1;
    }

  return len;
}

/* SIGCHLD handler that serves two purposes: In non-stop/async mode,
   so we notice when children change state; as the handler for the
   sigsuspend in my_waitpid.  */

static void
sigchld_handler (int signo)
{
  int old_errno = errno;

  if (debug_threads)
    /* fprintf is not async-signal-safe, so call write directly.  */
    write (2, "sigchld_handler\n", sizeof ("sigchld_handler\n") - 1);

  if (target_is_async_p ())
    async_file_mark (); /* trigger a linux_wait */

  errno = old_errno;
}

static int
linux_supports_non_stop (void)
{
  return 1;
}

static int
linux_async (int enable)
{
  int previous = (linux_event_pipe[0] != -1);

  if (debug_threads)
    fprintf (stderr, "linux_async (%d), previous=%d\n",
	     enable, previous);

  if (previous != enable)
    {
      sigset_t mask;
      sigemptyset (&mask);
      sigaddset (&mask, SIGCHLD);

      sigprocmask (SIG_BLOCK, &mask, NULL);

      if (enable)
	{
	  if (pipe (linux_event_pipe) == -1)
	    fatal ("creating event pipe failed.");

	  fcntl (linux_event_pipe[0], F_SETFL, O_NONBLOCK);
	  fcntl (linux_event_pipe[1], F_SETFL, O_NONBLOCK);

	  /* Register the event loop handler.  */
	  add_file_handler (linux_event_pipe[0],
			    handle_target_event, NULL);

	  /* Always trigger a linux_wait.  */
	  async_file_mark ();
	}
      else
	{
	  delete_file_handler (linux_event_pipe[0]);

	  close (linux_event_pipe[0]);
	  close (linux_event_pipe[1]);
	  linux_event_pipe[0] = -1;
	  linux_event_pipe[1] = -1;
	}

      sigprocmask (SIG_UNBLOCK, &mask, NULL);
    }

  return previous;
}

static int
linux_start_non_stop (int nonstop)
{
  /* Register or unregister from event-loop accordingly.  */
  linux_async (nonstop);
  return 0;
}

static int
linux_supports_multi_process (void)
{
  return 1;
}


/* Enumerate spufs IDs for process PID.  */
static int
spu_enumerate_spu_ids (long pid, unsigned char *buf, CORE_ADDR offset, int len)
{
  int pos = 0;
  int written = 0;
  char path[128];
  DIR *dir;
  struct dirent *entry;

  sprintf (path, "/proc/%ld/fd", pid);
  dir = opendir (path);
  if (!dir)
    return -1;

  rewinddir (dir);
  while ((entry = readdir (dir)) != NULL)
    {
      struct stat st;
      struct statfs stfs;
      int fd;

      fd = atoi (entry->d_name);
      if (!fd)
        continue;

      sprintf (path, "/proc/%ld/fd/%d", pid, fd);
      if (stat (path, &st) != 0)
        continue;
      if (!S_ISDIR (st.st_mode))
        continue;

      if (statfs (path, &stfs) != 0)
        continue;
      if (stfs.f_type != SPUFS_MAGIC)
        continue;

      if (pos >= offset && pos + 4 <= offset + len)
        {
          *(unsigned int *)(buf + pos - offset) = fd;
          written += 4;
        }
      pos += 4;
    }

  closedir (dir);
  return written;
}

/* Implements the to_xfer_partial interface for the TARGET_OBJECT_SPU
   object type, using the /proc file system.  */
static int
linux_qxfer_spu (const char *annex, unsigned char *readbuf,
		 unsigned const char *writebuf,
		 CORE_ADDR offset, int len)
{
  long pid = lwpid_of (get_thread_lwp (current_inferior));
  char buf[128];
  int fd = 0;
  int ret = 0;

  if (!writebuf && !readbuf)
    return -1;

  if (!*annex)
    {
      if (!readbuf)
	return -1;
      else
	return spu_enumerate_spu_ids (pid, readbuf, offset, len);
    }

  sprintf (buf, "/proc/%ld/fd/%s", pid, annex);
  fd = open (buf, writebuf? O_WRONLY : O_RDONLY);
  if (fd <= 0)
    return -1;

  if (offset != 0
      && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
    {
      close (fd);
      return 0;
    }

  if (writebuf)
    ret = write (fd, writebuf, (size_t) len);
  else
    ret = read (fd, readbuf, (size_t) len);

  close (fd);
  return ret;
}

static int
linux_core_of_thread (ptid_t ptid)
{
  char filename[sizeof ("/proc//task//stat")
		 + 2 * 20 /* decimal digits for 2 numbers, max 2^64 bit each */
		 + 1];
  FILE *f;
  char *content = NULL;
  char *p;
  char *ts = 0;
  int content_read = 0;
  int i;
  int core;

  sprintf (filename, "/proc/%d/task/%ld/stat",
	   ptid_get_pid (ptid), ptid_get_lwp (ptid));
  f = fopen (filename, "r");
  if (!f)
    return -1;

  for (;;)
    {
      int n;
      content = realloc (content, content_read + 1024);
      n = fread (content + content_read, 1, 1024, f);
      content_read += n;
      if (n < 1024)
	{
	  content[content_read] = '\0';
	  break;
	}
    }

  p = strchr (content, '(');

  /* Skip ")".  */
  if (p != NULL)
    p = strchr (p, ')');
  if (p != NULL)
    p++;

  /* If the first field after program name has index 0, then core number is
     the field with index 36.  There's no constant for that anywhere.  */
  if (p != NULL)
    p = strtok_r (p, " ", &ts);
  for (i = 0; p != NULL && i != 36; ++i)
    p = strtok_r (NULL, " ", &ts);

  if (p == NULL || sscanf (p, "%d", &core) == 0)
    core = -1;

  free (content);
  fclose (f);

  return core;
}

static void
linux_process_qsupported (const char *query)
{
  if (the_low_target.process_qsupported != NULL)
    the_low_target.process_qsupported (query);
}

static int
linux_supports_tracepoints (void)
{
  if (*the_low_target.supports_tracepoints == NULL)
    return 0;

  return (*the_low_target.supports_tracepoints) ();
}

static CORE_ADDR
linux_read_pc (struct regcache *regcache)
{
  if (the_low_target.get_pc == NULL)
    return 0;

  return (*the_low_target.get_pc) (regcache);
}

static void
linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
{
  gdb_assert (the_low_target.set_pc != NULL);

  (*the_low_target.set_pc) (regcache, pc);
}

static int
linux_thread_stopped (struct thread_info *thread)
{
  return get_thread_lwp (thread)->stopped;
}

/* This exposes stop-all-threads functionality to other modules.  */

static void
linux_pause_all (int freeze)
{
  stop_all_lwps (freeze, NULL);
}

/* This exposes unstop-all-threads functionality to other gdbserver
   modules.  */

static void
linux_unpause_all (int unfreeze)
{
  unstop_all_lwps (unfreeze, NULL);
}

static int
linux_install_fast_tracepoint_jump_pad (CORE_ADDR tpoint, CORE_ADDR tpaddr,
					CORE_ADDR collector,
					CORE_ADDR lockaddr,
					ULONGEST orig_size,
					CORE_ADDR *jump_entry,
					unsigned char *jjump_pad_insn,
					ULONGEST *jjump_pad_insn_size,
					CORE_ADDR *adjusted_insn_addr,
					CORE_ADDR *adjusted_insn_addr_end)
{
  return (*the_low_target.install_fast_tracepoint_jump_pad)
    (tpoint, tpaddr, collector, lockaddr, orig_size,
     jump_entry, jjump_pad_insn, jjump_pad_insn_size,
     adjusted_insn_addr, adjusted_insn_addr_end);
}

static struct emit_ops *
linux_emit_ops (void)
{
  if (the_low_target.emit_ops != NULL)
    return (*the_low_target.emit_ops) ();
  else
    return NULL;
}

static struct target_ops linux_target_ops = {
  linux_create_inferior,
  linux_attach,
  linux_kill,
  linux_detach,
  linux_mourn,
  linux_join,
  linux_thread_alive,
  linux_resume,
  linux_wait,
  linux_fetch_registers,
  linux_store_registers,
  linux_read_memory,
  linux_write_memory,
  linux_look_up_symbols,
  linux_request_interrupt,
  linux_read_auxv,
  linux_insert_point,
  linux_remove_point,
  linux_stopped_by_watchpoint,
  linux_stopped_data_address,
#if defined(__UCLIBC__) && defined(HAS_NOMMU)
  linux_read_offsets,
#else
  NULL,
#endif
#ifdef USE_THREAD_DB
  thread_db_get_tls_address,
#else
  NULL,
#endif
  linux_qxfer_spu,
  hostio_last_error_from_errno,
  linux_qxfer_osdata,
  linux_xfer_siginfo,
  linux_supports_non_stop,
  linux_async,
  linux_start_non_stop,
  linux_supports_multi_process,
#ifdef USE_THREAD_DB
  thread_db_handle_monitor_command,
#else
  NULL,
#endif
  linux_core_of_thread,
  linux_process_qsupported,
  linux_supports_tracepoints,
  linux_read_pc,
  linux_write_pc,
  linux_thread_stopped,
  NULL,
  linux_pause_all,
  linux_unpause_all,
  linux_cancel_breakpoints,
  linux_stabilize_threads,
  linux_install_fast_tracepoint_jump_pad,
  linux_emit_ops
};

static void
linux_init_signals ()
{
  /* FIXME drow/2002-06-09: As above, we should check with LinuxThreads
     to find what the cancel signal actually is.  */
#ifdef __SIGRTMIN /* Bionic doesn't use SIGRTMIN the way glibc does.  */
  signal (__SIGRTMIN+1, SIG_IGN);
#endif
}

void
initialize_low (void)
{
  struct sigaction sigchld_action;
  memset (&sigchld_action, 0, sizeof (sigchld_action));
  set_target_ops (&linux_target_ops);
  set_breakpoint_data (the_low_target.breakpoint,
		       the_low_target.breakpoint_len);
  linux_init_signals ();
  linux_test_for_tracefork ();
#ifdef HAVE_LINUX_REGSETS
  for (num_regsets = 0; target_regsets[num_regsets].size >= 0; num_regsets++)
    ;
  disabled_regsets = xmalloc (num_regsets);
#endif

  sigchld_action.sa_handler = sigchld_handler;
  sigemptyset (&sigchld_action.sa_mask);
  sigchld_action.sa_flags = SA_RESTART;
  sigaction (SIGCHLD, &sigchld_action, NULL);
}