aboutsummaryrefslogtreecommitdiff
path: root/gdb/pa64solib.c
blob: b67532d37599711ac1e96ef8feaf9cc4f67c070b (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
/* Handle HP ELF shared libraries for GDB, the GNU Debugger.

   Copyright 1999, 2000, 2001, 2002 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 2 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, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.

   HP in their infinite stupidity choose not to use standard ELF dynamic
   linker interfaces.  They also choose not to make their ELF dymamic
   linker interfaces compatible with the SOM dynamic linker.  The
   net result is we can not use either of the existing somsolib.c or
   solib.c.  What a crock.

   Even more disgusting.  This file depends on functions provided only
   in certain PA64 libraries.  Thus this file is supposed to only be
   used native.  When will HP ever learn that they need to provide the
   same functionality in all their libraries!  */

#include <dlfcn.h>
#include <elf.h>
#include <elf_hp.h>

#include "defs.h"

#include "frame.h"
#include "bfd.h"
#include "libhppa.h"
#include "gdbcore.h"
#include "symtab.h"
#include "breakpoint.h"
#include "symfile.h"
#include "objfiles.h"
#include "inferior.h"
#include "gdb-stabs.h"
#include "gdb_stat.h"
#include "gdbcmd.h"
#include "language.h"
#include "regcache.h"

#include <fcntl.h>

#ifndef O_BINARY
#define O_BINARY 0
#endif

/* Defined in exec.c; used to prevent dangling pointer bug.  */
extern struct target_ops exec_ops;

static CORE_ADDR bfd_lookup_symbol (bfd *, char *);
/* This lives in hppa-tdep.c. */
extern struct unwind_table_entry *find_unwind_entry (CORE_ADDR pc);

/* These ought to be defined in some public interface, but aren't.  They
   identify dynamic linker events.  */
#define DLD_CB_LOAD     1
#define DLD_CB_UNLOAD   0

/* A structure to keep track of all the known shared objects.  */
struct so_list
  {
    bfd *abfd;
    char *name;
    struct so_list *next;
    struct objfile *objfile;
    CORE_ADDR pa64_solib_desc_addr;
    struct load_module_desc pa64_solib_desc;
    struct section_table *sections;
    struct section_table *sections_end;
    int loaded;
  };

static struct so_list *so_list_head;

/* This is the cumulative size in bytes of the symbol tables of all
   shared objects on the so_list_head list.  (When we say size, here
   we mean of the information before it is brought into memory and
   potentially expanded by GDB.)  When adding a new shlib, this value
   is compared against a threshold size, held by auto_solib_limit (in
   megabytes).  If adding symbols for the new shlib would cause the
   total size to exceed the threshold, then the new shlib's symbols
   are not loaded. */
static LONGEST pa64_solib_total_st_size;

/* When the threshold is reached for any shlib, we refuse to add
   symbols for subsequent shlibs, even if those shlibs' symbols would
   be small enough to fit under the threshold.  Although this may
   result in one, early large shlib preventing the loading of later,
   smaller shlibs' symbols, it allows us to issue one informational
   message.  The alternative, to issue a message for each shlib whose
   symbols aren't loaded, could be a big annoyance where the threshold
   is exceeded due to a very large number of shlibs. */
static int pa64_solib_st_size_threshold_exceeded;

/* When adding fields, be sure to clear them in _initialize_pa64_solib. */
typedef struct
  {
    CORE_ADDR dld_flags_addr;
    LONGEST dld_flags;
    sec_ptr dyninfo_sect;
    int have_read_dld_descriptor;
    int is_valid;
    CORE_ADDR load_map;
    CORE_ADDR load_map_addr;
    struct load_module_desc dld_desc;
  }
dld_cache_t;

static dld_cache_t dld_cache;

static void pa64_sharedlibrary_info_command (char *, int);

static void pa64_solib_sharedlibrary_command (char *, int);

static void *pa64_target_read_memory (void *, CORE_ADDR, size_t, int);

static int read_dld_descriptor (struct target_ops *, int readsyms);

static int read_dynamic_info (asection *, dld_cache_t *);

static void add_to_solist (int, char *, int, struct load_module_desc *,
			   CORE_ADDR, struct target_ops *);

/* When examining the shared library for debugging information we have to
   look for HP debug symbols, stabs and dwarf2 debug symbols.  */
static char *pa64_debug_section_names[] = {
  ".debug_header", ".debug_gntt", ".debug_lntt", ".debug_slt", ".debug_vt",
  ".stabs", ".stabstr", ".debug_info", ".debug_abbrev", ".debug_aranges",
  ".debug_macinfo", ".debug_line", ".debug_loc", ".debug_pubnames",
  ".debug_str", NULL
};

/* Return a ballbark figure for the amount of memory GDB will need to
   allocate to read in the debug symbols from FILENAME.  */
static LONGEST
pa64_solib_sizeof_symbol_table (char *filename)
{
  bfd *abfd;
  int i;
  int desc;
  char *absolute_name;
  LONGEST st_size = (LONGEST) 0;
  asection *sect;

  /* We believe that filename was handed to us by the dynamic linker, and
     is therefore always an absolute path.  */
  desc = openp (getenv ("PATH"), 1, filename, O_RDONLY | O_BINARY,
		0, &absolute_name);
  if (desc < 0)
    {
      perror_with_name (filename);
    }
  filename = absolute_name;

  abfd = bfd_fdopenr (filename, gnutarget, desc);
  if (!abfd)
    {
      close (desc);
      make_cleanup (xfree, filename);
      error ("\"%s\": can't open to read symbols: %s.", filename,
	     bfd_errmsg (bfd_get_error ()));
    }

  if (!bfd_check_format (abfd, bfd_object))
    {
      bfd_close (abfd);
      make_cleanup (xfree, filename);
      error ("\"%s\": can't read symbols: %s.", filename,
	     bfd_errmsg (bfd_get_error ()));
    }

  /* Sum the sizes of the various sections that compose debug info. */
  for (i = 0; pa64_debug_section_names[i] != NULL; i++)
    {
      asection *sect;

      sect = bfd_get_section_by_name (abfd, pa64_debug_section_names[i]);
      if (sect)
	st_size += (LONGEST)bfd_section_size (abfd, sect);
    }

  bfd_close (abfd);
  xfree (filename);

  /* Unfortunately, just summing the sizes of various debug info
     sections isn't a very accurate measurement of how much heap
     space the debugger will need to hold them.  It also doesn't
     account for space needed by linker (aka "minimal") symbols.

     Anecdotal evidence suggests that just summing the sizes of
     debug-info-related sections understates the heap space needed
     to represent it internally by about an order of magnitude.

     Since it's not exactly brain surgery we're doing here, rather
     than attempt to more accurately measure the size of a shlib's
     symbol table in GDB's heap, we'll just apply a 10x fudge-
     factor to the debug info sections' size-sum.  No, this doesn't
     account for minimal symbols in non-debuggable shlibs.  But it
     all roughly washes out in the end.  */
  return st_size * (LONGEST) 10;
}

/* Add a shared library to the objfile list and load its symbols into
   GDB's symbol table.  */
static void
pa64_solib_add_solib_objfile (struct so_list *so, char *name, int from_tty,
			      CORE_ADDR text_addr)
{
  bfd *tmp_bfd;
  asection *sec;
  obj_private_data_t *obj_private;
  struct section_addr_info *section_addrs;
  struct cleanup *my_cleanups;

  /* We need the BFD so that we can look at its sections.  We open up the
     file temporarily, then close it when we are done.  */
  tmp_bfd = bfd_openr (name, gnutarget);
  if (tmp_bfd == NULL)
    {
      perror_with_name (name);
      return;
    }

  if (!bfd_check_format (tmp_bfd, bfd_object))
    {
      bfd_close (tmp_bfd);
      error ("\"%s\" is not an object file: %s", name,
	     bfd_errmsg (bfd_get_error ()));
    }


  /* Undo some braindamage from symfile.c.

     First, symfile.c will subtract the VMA of the first .text section
     in the shared library that it finds.  Undo that.  */
  sec = bfd_get_section_by_name (tmp_bfd, ".text");
  text_addr += bfd_section_vma (tmp_bfd, sec);

  /* Now find the true lowest section in the shared library.  */
  sec = NULL;
  bfd_map_over_sections (tmp_bfd, find_lowest_section, &sec);

  if (sec)
    {
      /* Subtract out the VMA of the lowest section.  */
      text_addr -= bfd_section_vma (tmp_bfd, sec);

      /* ??? Add back in the filepos of that lowest section. */
      text_addr += sec->filepos;
    }

  section_addrs = alloc_section_addr_info (bfd_count_sections (tmp_bfd));
  my_cleanups = make_cleanup (xfree, section_addrs);

  /* We are done with the temporary bfd.  Get rid of it and make sure
     nobody else can us it.  */
  bfd_close (tmp_bfd);
  tmp_bfd = NULL;

  /* Now let the generic code load up symbols for this library.  */
  section_addrs->other[0].addr = text_addr;
  section_addrs->other[0].name = ".text";
  so->objfile = symbol_file_add (name, from_tty, section_addrs, 0, OBJF_SHARED);
  so->abfd = so->objfile->obfd;

  /* Mark this as a shared library and save private data.  */
  so->objfile->flags |= OBJF_SHARED;

  if (so->objfile->obj_private == NULL)
    {
      obj_private = (obj_private_data_t *)
	obstack_alloc (&so->objfile->psymbol_obstack,
		       sizeof (obj_private_data_t));
      obj_private->unwind_info = NULL;
      obj_private->so_info = NULL;
      so->objfile->obj_private = obj_private;
    }

  obj_private = (obj_private_data_t *) so->objfile->obj_private;
  obj_private->so_info = so;
  obj_private->dp = so->pa64_solib_desc.linkage_ptr;
  do_cleanups (my_cleanups);
}

/* Load debugging information for a shared library.  TARGET may be
   NULL if we are not attaching to a process or reading a core file.  */

static void
pa64_solib_load_symbols (struct so_list *so, char *name, int from_tty,
			 CORE_ADDR text_addr, struct target_ops *target)
{
  struct section_table *p;
  asection *sec;
  int status;
  char buf[4];
  CORE_ADDR presumed_data_start;

  if (text_addr == 0)
    text_addr = so->pa64_solib_desc.text_base;

  pa64_solib_add_solib_objfile (so, name, from_tty, text_addr);

  /* Now we need to build a section table for this library since
     we might be debugging a core file from a dynamically linked
     executable in which the libraries were not privately mapped.  */
  if (build_section_table (so->abfd,
			   &so->sections,
			   &so->sections_end))
    {
      error ("Unable to build section table for shared library\n.");
      return;
    }

  (so->objfile->section_offsets)->offsets[SECT_OFF_TEXT (so->objfile)]
    = so->pa64_solib_desc.text_base;
  (so->objfile->section_offsets)->offsets[SECT_OFF_DATA (so->objfile)]
    = so->pa64_solib_desc.data_base;

  /* Relocate all the sections based on where they got loaded.  */
  for (p = so->sections; p < so->sections_end; p++)
    {
      if (p->the_bfd_section->flags & SEC_CODE)
	{
	  p->addr += ANOFFSET (so->objfile->section_offsets, SECT_OFF_TEXT (so->objfile));
	  p->endaddr += ANOFFSET (so->objfile->section_offsets, SECT_OFF_TEXT (so->objfile));
	}
      else if (p->the_bfd_section->flags & SEC_DATA)
	{
	  p->addr += ANOFFSET (so->objfile->section_offsets, SECT_OFF_DATA (so->objfile));
	  p->endaddr += ANOFFSET (so->objfile->section_offsets, SECT_OFF_DATA (so->objfile));
	}
    }

  /* Now see if we need to map in the text and data for this shared
     library (for example debugging a core file which does not use
     private shared libraries.). 

     Carefully peek at the first text address in the library.  If the
     read succeeds, then the libraries were privately mapped and were
     included in the core dump file.

     If the peek failed, then the libraries were not privately mapped
     and are not in the core file, we'll have to read them in ourselves.  */
  status = target_read_memory (text_addr, buf, 4);
  if (status != 0)
    {
      int new, old;
      
      new = so->sections_end - so->sections;

      old = target_resize_to_sections (target, new);
      
      /* Copy over the old data before it gets clobbered.  */
      memcpy ((char *) (target->to_sections + old),
	      so->sections,
	      ((sizeof (struct section_table)) * new));
    }
}


/* Add symbols from shared libraries into the symtab list, unless the
   size threshold specified by auto_solib_limit (in megabytes) would
   be exceeded.  */

void
pa64_solib_add (char *arg_string, int from_tty, struct target_ops *target, int readsyms)
{
  struct minimal_symbol *msymbol;
  CORE_ADDR addr;
  asection *shlib_info;
  int status;
  unsigned int dld_flags;
  char buf[4], *re_err;
  int threshold_warning_given = 0;
  int dll_index;
  struct load_module_desc dll_desc;
  char *dll_path;

  /* First validate our arguments.  */
  if ((re_err = re_comp (arg_string ? arg_string : ".")) != NULL)
    {
      error ("Invalid regexp: %s", re_err);
    }

  /* If we're debugging a core file, or have attached to a running
     process, then pa64_solib_create_inferior_hook will not have been
     called.

     We need to first determine if we're dealing with a dynamically
     linked executable.  If not, then return without an error or warning.

     We also need to examine __dld_flags to determine if the shared library
     list is valid and to determine if the libraries have been privately
     mapped.  */
  if (symfile_objfile == NULL)
    return;

  /* First see if the objfile was dynamically linked.  */
  shlib_info = bfd_get_section_by_name (symfile_objfile->obfd, ".dynamic");
  if (!shlib_info)
    return;

  /* It's got a .dynamic section, make sure it's not empty.  */
  if (bfd_section_size (symfile_objfile->obfd, shlib_info) == 0)
    return;

  /* Read in the load map pointer if we have not done so already.  */
  if (! dld_cache.have_read_dld_descriptor)
    if (! read_dld_descriptor (target, readsyms))
      return;

  /* If the libraries were not mapped private, warn the user.  */
  if ((dld_cache.dld_flags & DT_HP_DEBUG_PRIVATE) == 0)
    warning ("The shared libraries were not privately mapped; setting a\nbreakpoint in a shared library will not work until you rerun the program.\n");

  /* For each shaerd library, add it to the shared library list.  */
  for (dll_index = 1; ; dll_index++)
    {
      /* Read in the load module descriptor.  */
      if (dlgetmodinfo (dll_index, &dll_desc, sizeof (dll_desc),
			pa64_target_read_memory, 0, dld_cache.load_map)
	  == 0)
	return;

      /* Get the name of the shared library.  */
      dll_path = (char *)dlgetname (&dll_desc, sizeof (dll_desc),
			    pa64_target_read_memory,
			    0, dld_cache.load_map);

      if (!dll_path)
	error ("pa64_solib_add, unable to read shared library path.");

      add_to_solist (from_tty, dll_path, readsyms, &dll_desc, 0, target);
    }
}


/* This hook gets called just before the first instruction in the
   inferior process is executed.

   This is our opportunity to set magic flags in the inferior so
   that GDB can be notified when a shared library is mapped in and
   to tell the dynamic linker that a private copy of the library is
   needed (so GDB can set breakpoints in the library).

   We need to set two flag bits in this routine.

     DT_HP_DEBUG_PRIVATE to indicate that shared libraries should be
     mapped private.

     DT_HP_DEBUG_CALLBACK to indicate that we want the dynamic linker to
     call the breakpoint routine for significant events.  */

void
pa64_solib_create_inferior_hook (void)
{
  struct minimal_symbol *msymbol;
  unsigned int dld_flags, status;
  asection *shlib_info, *interp_sect;
  char buf[4];
  struct objfile *objfile;
  CORE_ADDR anaddr;

  /* First, remove all the solib event breakpoints.  Their addresses
     may have changed since the last time we ran the program.  */
  remove_solib_event_breakpoints ();

  if (symfile_objfile == NULL)
    return;

  /* First see if the objfile was dynamically linked.  */
  shlib_info = bfd_get_section_by_name (symfile_objfile->obfd, ".dynamic");
  if (!shlib_info)
    return;

  /* It's got a .dynamic section, make sure it's not empty.  */
  if (bfd_section_size (symfile_objfile->obfd, shlib_info) == 0)
    return;

  /* Read in the .dynamic section.  */
  if (! read_dynamic_info (shlib_info, &dld_cache))
    error ("Unable to read the .dynamic section.");

  /* Turn on the flags we care about.  */
  dld_cache.dld_flags |= DT_HP_DEBUG_PRIVATE;
  dld_cache.dld_flags |= DT_HP_DEBUG_CALLBACK;
  status = target_write_memory (dld_cache.dld_flags_addr,
				(char *) &dld_cache.dld_flags,
				sizeof (dld_cache.dld_flags));
  if (status != 0)
    error ("Unable to modify dynamic linker flags.");

  /* Now we have to create a shared library breakpoint in the dynamic
     linker.  This can be somewhat tricky since the symbol is inside
     the dynamic linker (for which we do not have symbols or a base
     load address!   Luckily I wrote this code for solib.c years ago.  */
  interp_sect = bfd_get_section_by_name (exec_bfd, ".interp");
  if (interp_sect)
    {
      unsigned int interp_sect_size;
      char *buf;
      CORE_ADDR load_addr;
      bfd *tmp_bfd;
      CORE_ADDR sym_addr = 0;

      /* Read the contents of the .interp section into a local buffer;
	 the contents specify the dynamic linker this program uses.  */
      interp_sect_size = bfd_section_size (exec_bfd, interp_sect);
      buf = alloca (interp_sect_size);
      bfd_get_section_contents (exec_bfd, interp_sect,
				buf, 0, interp_sect_size);

      /* Now we need to figure out where the dynamic linker was
	 loaded so that we can load its symbols and place a breakpoint
	 in the dynamic linker itself.

	 This address is stored on the stack.  However, I've been unable
	 to find any magic formula to find it for Solaris (appears to
	 be trivial on GNU/Linux).  Therefore, we have to try an alternate
	 mechanism to find the dynamic linker's base address.  */
      tmp_bfd = bfd_openr (buf, gnutarget);
      if (tmp_bfd == NULL)
	goto get_out;

      /* Make sure the dynamic linker's really a useful object.  */
      if (!bfd_check_format (tmp_bfd, bfd_object))
	{
	  warning ("Unable to grok dynamic linker %s as an object file", buf);
	  bfd_close (tmp_bfd);
	  goto get_out;
	}

      /* We find the dynamic linker's base address by examining the
	 current pc (which point at the entry point for the dynamic
	 linker) and subtracting the offset of the entry point. 

	 Also note the breakpoint is the second instruction in the
	 routine.  */
      load_addr = read_pc () - tmp_bfd->start_address;
      sym_addr = bfd_lookup_symbol (tmp_bfd, "__dld_break");
      sym_addr = load_addr + sym_addr + 4;
      
      /* Create the shared library breakpoint.  */
      {
	struct breakpoint *b
	  = create_solib_event_breakpoint (sym_addr);

	/* The breakpoint is actually hard-coded into the dynamic linker,
	   so we don't need to actually insert a breakpoint instruction
	   there.  In fact, the dynamic linker's code is immutable, even to
	   ttrace, so we shouldn't even try to do that.  For cases like
	   this, we have "permanent" breakpoints.  */
	make_breakpoint_permanent (b);
      }

      /* We're done with the temporary bfd.  */
      bfd_close (tmp_bfd);
    }

get_out:
  /* Wipe out all knowledge of old shared libraries since their
     mapping can change from one exec to another!  */
  while (so_list_head)
    {
      struct so_list *temp;

      temp = so_list_head;
      xfree (so_list_head);
      so_list_head = temp->next;
    }
  clear_symtab_users ();
}

/* This operation removes the "hook" between GDB and the dynamic linker,
   which causes the dld to notify GDB of shared library events.

   After this operation completes, the dld will no longer notify GDB of
   shared library events.  To resume notifications, GDB must call
   pa64_solib_create_inferior_hook.

   This operation does not remove any knowledge of shared libraries which
   GDB may already have been notified of.  */

void
pa64_solib_remove_inferior_hook (int pid)
{
  /* Turn off the DT_HP_DEBUG_CALLBACK bit in the dynamic linker flags.  */
  dld_cache.dld_flags &= ~DT_HP_DEBUG_CALLBACK;
  target_write_memory (dld_cache.dld_flags_addr,
		       (char *)&dld_cache.dld_flags,
		       sizeof (dld_cache.dld_flags));
}

/* This function creates a breakpoint on the dynamic linker hook, which
   is called when e.g., a shl_load or shl_unload call is made.  This
   breakpoint will only trigger when a shl_load call is made.

   If filename is NULL, then loads of any dll will be caught.  Else,
   only loads of the file whose pathname is the string contained by
   filename will be caught.

   Undefined behaviour is guaranteed if this function is called before
   pa64_solib_create_inferior_hook.  */

void
pa64_solib_create_catch_load_hook (int pid, int tempflag, char *filename,
				   char *cond_string)
{
  create_solib_load_event_breakpoint ("", tempflag, filename, cond_string);
}

/* This function creates a breakpoint on the dynamic linker hook, which
   is called when e.g., a shl_load or shl_unload call is made.  This
   breakpoint will only trigger when a shl_unload call is made.

   If filename is NULL, then unloads of any dll will be caught.  Else,
   only unloads of the file whose pathname is the string contained by
   filename will be caught.

   Undefined behaviour is guaranteed if this function is called before
   pa64_solib_create_inferior_hook.  */

void
pa64_solib_create_catch_unload_hook (int pid, int tempflag, char *filename,
				     char *cond_string)
{
  create_solib_unload_event_breakpoint ("", tempflag, filename, cond_string);
}

/* Return nonzero if the dynamic linker has reproted that a library
   has been loaded.  */

int
pa64_solib_have_load_event (int pid)
{
  CORE_ADDR event_kind;

  event_kind = read_register (ARG0_REGNUM);
  return (event_kind == DLD_CB_LOAD);
}

/* Return nonzero if the dynamic linker has reproted that a library
   has been unloaded.  */
int
pa64_solib_have_unload_event (int pid)
{
  CORE_ADDR event_kind;

  event_kind = read_register (ARG0_REGNUM);
  return (event_kind == DLD_CB_UNLOAD);
}

/* Return a pointer to a string indicating the pathname of the most
   recently loaded library.

   The caller is reposible for copying the string before the inferior is
   restarted.  */

char *
pa64_solib_loaded_library_pathname (int pid)
{
  static char dll_path[MAXPATHLEN];
  CORE_ADDR  dll_path_addr = read_register (ARG3_REGNUM);
  read_memory_string (dll_path_addr, dll_path, MAXPATHLEN);
  return dll_path;
}

/* Return a pointer to a string indicating the pathname of the most
   recently unloaded library.

   The caller is reposible for copying the string before the inferior is
   restarted.  */

char *
pa64_solib_unloaded_library_pathname (int pid)
{
  static char dll_path[MAXPATHLEN];
  CORE_ADDR dll_path_addr = read_register (ARG3_REGNUM);
  read_memory_string (dll_path_addr, dll_path, MAXPATHLEN);
  return dll_path;
}

/* Return nonzero if PC is an address inside the dynamic linker.  */

int
pa64_solib_in_dynamic_linker (int pid, CORE_ADDR pc)
{
  asection *shlib_info;

  if (symfile_objfile == NULL)
    return 0;

  if (!dld_cache.have_read_dld_descriptor)
    if (!read_dld_descriptor (&current_target, auto_solib_add))
      return 0;

  return (pc >= dld_cache.dld_desc.text_base
	  && pc < dld_cache.dld_desc.text_base + dld_cache.dld_desc.text_size);
}


/* Return the GOT value for the shared library in which ADDR belongs.  If
   ADDR isn't in any known shared library, return zero.  */

CORE_ADDR
pa64_solib_get_got_by_pc (CORE_ADDR addr)
{
  struct so_list *so_list = so_list_head;
  CORE_ADDR got_value = 0;

  while (so_list)
    {
      if (so_list->pa64_solib_desc.text_base <= addr
	  && ((so_list->pa64_solib_desc.text_base
	       + so_list->pa64_solib_desc.text_size)
	      > addr))
	{
	  got_value = so_list->pa64_solib_desc.linkage_ptr;
	  break;
	}
      so_list = so_list->next;
    }
  return got_value;
}

/* Return the address of the handle of the shared library in which ADDR
   belongs.  If ADDR isn't in any known shared library, return zero. 

   This function is used in hppa_fix_call_dummy in hppa-tdep.c.  */

CORE_ADDR
pa64_solib_get_solib_by_pc (CORE_ADDR addr)
{
  struct so_list *so_list = so_list_head;
  CORE_ADDR retval = 0;

  while (so_list)
    {
      if (so_list->pa64_solib_desc.text_base <= addr
	  && ((so_list->pa64_solib_desc.text_base
	       + so_list->pa64_solib_desc.text_size)
	      > addr))
	{
	  retval = so_list->pa64_solib_desc_addr;
	  break;
	}
      so_list = so_list->next;
    }
  return retval;
}

/* Dump information about all the currently loaded shared libraries.  */

static void
pa64_sharedlibrary_info_command (char *ignore, int from_tty)
{
  struct so_list *so_list = so_list_head;

  if (exec_bfd == NULL)
    {
      printf_unfiltered ("No executable file.\n");
      return;
    }

  if (so_list == NULL)
    {
      printf_unfiltered ("No shared libraries loaded at this time.\n");
      return;
    }

  printf_unfiltered ("Shared Object Libraries\n");
  printf_unfiltered ("   %-19s%-19s%-19s%-19s\n",
		     "  text start", "   text end",
		     "  data start", "   data end");
  while (so_list)
    {
      unsigned int flags;

      printf_unfiltered ("%s", so_list->name);
      if (so_list->objfile == NULL)
	printf_unfiltered ("  (symbols not loaded)");
      if (so_list->loaded == 0)
	printf_unfiltered ("  (shared library unloaded)");
      printf_unfiltered ("  %-18s",
	local_hex_string_custom (so_list->pa64_solib_desc.linkage_ptr,
				 "016l"));
      printf_unfiltered ("\n");
      printf_unfiltered ("%-18s",
	local_hex_string_custom (so_list->pa64_solib_desc.text_base,
				 "016l"));
      printf_unfiltered (" %-18s",
	local_hex_string_custom ((so_list->pa64_solib_desc.text_base
				  + so_list->pa64_solib_desc.text_size),
				 "016l"));
      printf_unfiltered (" %-18s",
	local_hex_string_custom (so_list->pa64_solib_desc.data_base,
				 "016l"));
      printf_unfiltered (" %-18s\n",
	local_hex_string_custom ((so_list->pa64_solib_desc.data_base
				  + so_list->pa64_solib_desc.data_size),
				 "016l"));
      so_list = so_list->next;
    }
}

/* Load up one or more shared libraries as directed by the user.  */

static void
pa64_solib_sharedlibrary_command (char *args, int from_tty)
{
  dont_repeat ();
  pa64_solib_add (args, from_tty, (struct target_ops *) 0, 1);
}

/* Return the name of the shared library containing ADDR or NULL if ADDR
   is not contained in any known shared library.  */

char *
pa64_solib_address (CORE_ADDR addr)
{
  struct so_list *so = so_list_head;

  while (so)
    {
      /* Is this address within this shlib's text range?  If so,
	 return the shlib's name.  */
      if (addr >= so->pa64_solib_desc.text_base
	  && addr < (so->pa64_solib_desc.text_base
		     | so->pa64_solib_desc.text_size))
	return so->name;

      /* Nope, keep looking... */
      so = so->next;
    }

  /* No, we couldn't prove that the address is within a shlib. */
  return NULL;
}

/* We are killing the inferior and restarting the program.  */

void
pa64_solib_restart (void)
{
  struct so_list *sl = so_list_head;

  /* Before the shlib info vanishes, use it to disable any breakpoints
     that may still be active in those shlibs.  */
  disable_breakpoints_in_shlibs (0);

  /* Discard all the shlib descriptors.  */
  while (sl)
    {
      struct so_list *next_sl = sl->next;
      xfree (sl);
      sl = next_sl;
    }
  so_list_head = NULL;

  pa64_solib_total_st_size = (LONGEST) 0;
  pa64_solib_st_size_threshold_exceeded = 0;

  dld_cache.is_valid = 0;
  dld_cache.have_read_dld_descriptor = 0;
  dld_cache.dld_flags_addr = 0;
  dld_cache.load_map = 0;
  dld_cache.load_map_addr = 0;
  dld_cache.dld_desc.data_base = 0;
  dld_cache.dld_flags = 0;
  dld_cache.dyninfo_sect = 0;
}

void
_initialize_pa64_solib (void)
{
  add_com ("sharedlibrary", class_files, pa64_solib_sharedlibrary_command,
	   "Load shared object library symbols for files matching REGEXP.");
  add_info ("sharedlibrary", pa64_sharedlibrary_info_command,
	    "Status of loaded shared object libraries.");

  add_show_from_set
    (add_set_cmd ("auto-solib-add", class_support, var_boolean,
		  (char *) &auto_solib_add,
		  "Set autoloading of shared library symbols.\n\
If \"on\", symbols from all shared object libraries will be loaded\n\
automatically when the inferior begins execution, when the dynamic linker\n\
informs gdb that a new library has been loaded, or when attaching to the\n\
inferior.  Otherwise, symbols must be loaded manually, using `sharedlibrary'.",
		  &setlist),
     &showlist);

  add_show_from_set
    (add_set_cmd ("auto-solib-limit", class_support, var_zinteger,
		  (char *) &auto_solib_limit,
		  "Set threshold (in Mb) for autoloading shared library symbols.\n\
When shared library autoloading is enabled, new libraries will be loaded\n\
only until the total size of shared library symbols exceeds this\n\
threshold in megabytes.  Is ignored when using `sharedlibrary'.",
		  &setlist),
     &showlist);

  /* ??rehrauer: On HP-UX, the kernel parameter MAXDSIZ limits how
     much data space a process can use.  We ought to be reading
     MAXDSIZ and setting auto_solib_limit to some large fraction of
     that value.  If not that, we maybe ought to be setting it smaller
     than the default for MAXDSIZ (that being 64Mb, I believe).
     However, [1] this threshold is only crudely approximated rather
     than actually measured, and [2] 50 Mbytes is too small for
     debugging gdb itself.  Thus, the arbitrary 100 figure.  */
  auto_solib_limit = 100;	/* Megabytes */

  pa64_solib_restart ();
}

/* Get some HPUX-specific data from a shared lib.  */
CORE_ADDR
so_lib_thread_start_addr (struct so_list *so)
{
  return so->pa64_solib_desc.tls_start_addr;
}

/* Read the dynamic linker's internal shared library descriptor.

   This must happen after dld starts running, so we can't do it in
   read_dynamic_info.  Record the fact that we have loaded the
   descriptor.  If the library is archive bound, then return zero, else
   return nonzero.  */

static int
read_dld_descriptor (struct target_ops *target, int readsyms)
{
  char *dll_path;
  asection *dyninfo_sect;

  /* If necessary call read_dynamic_info to extract the contents of the
     .dynamic section from the shared library.  */
  if (!dld_cache.is_valid) 
    {
      if (symfile_objfile == NULL)
	error ("No object file symbols.");

      dyninfo_sect = bfd_get_section_by_name (symfile_objfile->obfd, 
					      ".dynamic");
      if (!dyninfo_sect) 
	{
	  return 0;
	}

      if (!read_dynamic_info (dyninfo_sect, &dld_cache))
	error ("Unable to read in .dynamic section information.");
    }

  /* Read the load map pointer.  */
  if (target_read_memory (dld_cache.load_map_addr,
			  (char*) &dld_cache.load_map,
			  sizeof(dld_cache.load_map))
      != 0)
    {
      error ("Error while reading in load map pointer.");
    }

  /* Read in the dld load module descriptor */
  if (dlgetmodinfo (-1, 
		    &dld_cache.dld_desc,
		    sizeof(dld_cache.dld_desc), 
		    pa64_target_read_memory, 
		    0, 
		    dld_cache.load_map)
      == 0)
    {
      error ("Error trying to get information about dynamic linker.");
    }

  /* Indicate that we have loaded the dld descriptor.  */
  dld_cache.have_read_dld_descriptor = 1;

  /* Add dld.sl to the list of known shared libraries so that we can
     do unwind, etc. 

     ?!? This may not be correct.  Consider of dld.sl contains symbols
     which are also referenced/defined by the user program or some user
     shared library.  We need to make absolutely sure that we do not
     pollute the namespace from GDB's point of view.  */
  dll_path = dlgetname (&dld_cache.dld_desc, 
			sizeof(dld_cache.dld_desc), 
			pa64_target_read_memory, 
			0, 
			dld_cache.load_map);
  add_to_solist(0, dll_path, readsyms, &dld_cache.dld_desc, 0, target);
  
  return 1;
}

/* Read the .dynamic section and extract the information of interest,
   which is stored in dld_cache.  The routine elf_locate_base in solib.c 
   was used as a model for this.  */

static int
read_dynamic_info (asection *dyninfo_sect, dld_cache_t *dld_cache_p)
{
  char *buf;
  char *bufend;
  CORE_ADDR dyninfo_addr;
  int dyninfo_sect_size;
  CORE_ADDR entry_addr;

  /* Read in .dynamic section, silently ignore errors.  */
  dyninfo_addr = bfd_section_vma (symfile_objfile->obfd, dyninfo_sect);
  dyninfo_sect_size = bfd_section_size (exec_bfd, dyninfo_sect);
  buf = alloca (dyninfo_sect_size);
  if (target_read_memory (dyninfo_addr, buf, dyninfo_sect_size))
    return 0;

  /* Scan the .dynamic section and record the items of interest. 
     In particular, DT_HP_DLD_FLAGS */
  for (bufend = buf + dyninfo_sect_size, entry_addr = dyninfo_addr;
       buf < bufend;
       buf += sizeof (Elf64_Dyn), entry_addr += sizeof (Elf64_Dyn))
    {
      Elf64_Dyn *x_dynp = (Elf64_Dyn*)buf;
      Elf64_Sxword dyn_tag;
      CORE_ADDR	dyn_ptr;
      char *pbuf;

      pbuf = alloca (TARGET_PTR_BIT / HOST_CHAR_BIT);
      dyn_tag = bfd_h_get_64 (symfile_objfile->obfd, 
			      (bfd_byte*) &x_dynp->d_tag);

      /* We can't use a switch here because dyn_tag is 64 bits and HP's
	 lame comiler does not handle 64bit items in switch statements.  */
      if (dyn_tag == DT_NULL)
	break;
      else if (dyn_tag == DT_HP_DLD_FLAGS)
	{
	  /* Set dld_flags_addr and dld_flags in *dld_cache_p */
	  dld_cache_p->dld_flags_addr = entry_addr + offsetof(Elf64_Dyn, d_un);
	  if (target_read_memory (dld_cache_p->dld_flags_addr,
	  			  (char*) &dld_cache_p->dld_flags, 
				  sizeof(dld_cache_p->dld_flags))
	      != 0)
	    {
	      error ("Error while reading in .dynamic section of the program.");
	    }
	}
      else if (dyn_tag == DT_HP_LOAD_MAP)
	{
	  /* Dld will place the address of the load map at load_map_addr
	     after it starts running.  */
	  if (target_read_memory (entry_addr + offsetof(Elf64_Dyn, 
							d_un.d_ptr),
				  (char*) &dld_cache_p->load_map_addr,
				  sizeof(dld_cache_p->load_map_addr))
	      != 0)
	    {
	      error ("Error while reading in .dynamic section of the program.");
	    }
	}
      else 
	{
	  /* tag is not of interest */
	}
    }

  /* Record other information and set is_valid to 1. */
  dld_cache_p->dyninfo_sect = dyninfo_sect;

  /* Verify that we read in required info.  These fields are re-set to zero
     in pa64_solib_restart.  */

  if (dld_cache_p->dld_flags_addr != 0 && dld_cache_p->load_map_addr != 0) 
    dld_cache_p->is_valid = 1;
  else 
    return 0;

  return 1;
}

/* Wrapper for target_read_memory to make dlgetmodinfo happy.  */

static void *
pa64_target_read_memory (void *buffer, CORE_ADDR ptr, size_t bufsiz, int ident)
{
  if (target_read_memory (ptr, buffer, bufsiz) != 0)
    return 0;
  return buffer;
}

/* Called from handle_dynlink_load_event and pa64_solib_add to add
   a shared library to so_list_head list and possibly to read in the
   debug information for the library.  

   If load_module_desc_p is NULL, then the load module descriptor must
   be read from the inferior process at the address load_module_desc_addr.  */

static void
add_to_solist (int from_tty, char *dll_path, int readsyms,
	       struct load_module_desc *load_module_desc_p,
	       CORE_ADDR load_module_desc_addr, struct target_ops *target)
{
  struct so_list *new_so, *so_list_tail;
  int pa64_solib_st_size_threshhold_exceeded;
  LONGEST st_size;

  if (symfile_objfile == NULL)
    return;

  so_list_tail = so_list_head;
  /* Find the end of the list of shared objects.  */
  while (so_list_tail && so_list_tail->next)
    {
      if (strcmp (so_list_tail->name, dll_path) == 0)
	return;
      so_list_tail = so_list_tail->next;
    }

  if (so_list_tail && strcmp (so_list_tail->name, dll_path) == 0)
    return;

  /* Add the shared library to the so_list_head list */
  new_so = (struct so_list *) xmalloc (sizeof (struct so_list));
  memset ((char *)new_so, 0, sizeof (struct so_list));
  if (so_list_head == NULL)
    {
      so_list_head = new_so;
      so_list_tail = new_so;
    }
  else
    {
      so_list_tail->next = new_so;
      so_list_tail = new_so;
    }

  /* Initialize the new_so */
  if (load_module_desc_p)
    {
      new_so->pa64_solib_desc = *load_module_desc_p;
    }
  else
    {
      if (target_read_memory (load_module_desc_addr, 
			      (char*) &new_so->pa64_solib_desc,
			      sizeof(struct load_module_desc))
	  != 0)
      {
	error ("Error while reading in dynamic library %s", dll_path);
      }
    }
  
  new_so->pa64_solib_desc_addr = load_module_desc_addr;
  new_so->loaded = 1;
  new_so->name = obsavestring (dll_path, strlen(dll_path),
			       &symfile_objfile->symbol_obstack);

  /* If we are not going to load the library, tell the user if we
     haven't already and return.  */

  st_size = pa64_solib_sizeof_symbol_table (dll_path);
  pa64_solib_st_size_threshhold_exceeded =
       !from_tty 
    && readsyms
    && (  (st_size + pa64_solib_total_st_size) 
	> (auto_solib_limit * (LONGEST) (1024 * 1024)));
  if (pa64_solib_st_size_threshhold_exceeded)
    {
      pa64_solib_add_solib_objfile (new_so, dll_path, from_tty, 1);
      return;
    } 

  /* Now read in debug info. */
  pa64_solib_total_st_size += st_size;

  /* This fills in new_so->objfile, among others. */
  pa64_solib_load_symbols (new_so, 
			   dll_path,
			   from_tty, 
			   0,
			   target);
  return;
}


/*
   LOCAL FUNCTION

   bfd_lookup_symbol -- lookup the value for a specific symbol

   SYNOPSIS

   CORE_ADDR bfd_lookup_symbol (bfd *abfd, char *symname)

   DESCRIPTION

   An expensive way to lookup the value of a single symbol for
   bfd's that are only temporary anyway.  This is used by the
   shared library support to find the address of the debugger
   interface structures in the shared library.

   Note that 0 is specifically allowed as an error return (no
   such symbol).
 */

static CORE_ADDR
bfd_lookup_symbol (bfd *abfd, char *symname)
{
  unsigned int storage_needed;
  asymbol *sym;
  asymbol **symbol_table;
  unsigned int number_of_symbols;
  unsigned int i;
  struct cleanup *back_to;
  CORE_ADDR symaddr = 0;

  storage_needed = bfd_get_symtab_upper_bound (abfd);

  if (storage_needed > 0)
    {
      symbol_table = (asymbol **) xmalloc (storage_needed);
      back_to = make_cleanup (xfree, symbol_table);
      number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);

      for (i = 0; i < number_of_symbols; i++)
	{
	  sym = *symbol_table++;
	  if (strcmp (sym->name, symname) == 0)
	    {
	      /* Bfd symbols are section relative. */
	      symaddr = sym->value + sym->section->vma;
	      break;
	    }
	}
      do_cleanups (back_to);
    }
  return (symaddr);
}