aboutsummaryrefslogtreecommitdiff
path: root/gdb/corelow.c
blob: 49de82d6352e77478ce958e40de8eda18b9c0859 (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
/* Core dump and executable file functions below target vector, for GDB.

   Copyright (C) 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
   1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009
   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 "defs.h"
#include "arch-utils.h"
#include "gdb_string.h"
#include <errno.h>
#include <signal.h>
#include <fcntl.h>
#ifdef HAVE_SYS_FILE_H
#include <sys/file.h>		/* needed for F_OK and friends */
#endif
#include "frame.h"		/* required by inferior.h */
#include "inferior.h"
#include "symtab.h"
#include "command.h"
#include "bfd.h"
#include "target.h"
#include "gdbcore.h"
#include "gdbthread.h"
#include "regcache.h"
#include "regset.h"
#include "symfile.h"
#include "exec.h"
#include "readline/readline.h"
#include "gdb_assert.h"
#include "exceptions.h"
#include "solib.h"
#include "filenames.h"


#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif

/* List of all available core_fns.  On gdb startup, each core file
   register reader calls deprecated_add_core_fns() to register
   information on each core format it is prepared to read.  */

static struct core_fns *core_file_fns = NULL;

/* The core_fns for a core file handler that is prepared to read the core
   file currently open on core_bfd. */

static struct core_fns *core_vec = NULL;

/* FIXME: kettenis/20031023: Eventually this variable should
   disappear.  */

struct gdbarch *core_gdbarch = NULL;

/* Per-core data.  Currently, only the section table.  Note that these
   target sections are *not* mapped in the current address spaces' set
   of target sections --- those should come only from pure executable
   or shared library bfds.  The core bfd sections are an
   implementation detail of the core target, just like ptrace is for
   unix child targets.  */
static struct target_section_table *core_data;

static void core_files_info (struct target_ops *);

static struct core_fns *sniff_core_bfd (bfd *);

static int gdb_check_format (bfd *);

static void core_open (char *, int);

static void core_detach (struct target_ops *ops, char *, int);

static void core_close (int);

static void core_close_cleanup (void *ignore);

static void add_to_thread_list (bfd *, asection *, void *);

static void init_core_ops (void);

void _initialize_corelow (void);

struct target_ops core_ops;

/* An arbitrary identifier for the core inferior.  */
#define CORELOW_PID 1

/* Link a new core_fns into the global core_file_fns list.  Called on gdb
   startup by the _initialize routine in each core file register reader, to
   register information about each format the the reader is prepared to
   handle. */

void
deprecated_add_core_fns (struct core_fns *cf)
{
  cf->next = core_file_fns;
  core_file_fns = cf;
}

/* The default function that core file handlers can use to examine a
   core file BFD and decide whether or not to accept the job of
   reading the core file. */

int
default_core_sniffer (struct core_fns *our_fns, bfd *abfd)
{
  int result;

  result = (bfd_get_flavour (abfd) == our_fns -> core_flavour);
  return (result);
}

/* Walk through the list of core functions to find a set that can
   handle the core file open on ABFD.  Default to the first one in the
   list if nothing matches.  Returns pointer to set that is
   selected. */

static struct core_fns *
sniff_core_bfd (bfd *abfd)
{
  struct core_fns *cf;
  struct core_fns *yummy = NULL;
  int matches = 0;;

  /* Don't sniff if we have support for register sets in CORE_GDBARCH.  */
  if (core_gdbarch && gdbarch_regset_from_core_section_p (core_gdbarch))
    return NULL;

  for (cf = core_file_fns; cf != NULL; cf = cf->next)
    {
      if (cf->core_sniffer (cf, abfd))
	{
	  yummy = cf;
	  matches++;
	}
    }
  if (matches > 1)
    {
      warning (_("\"%s\": ambiguous core format, %d handlers match"),
	       bfd_get_filename (abfd), matches);
    }
  else if (matches == 0)
    {
      warning (_("\"%s\": no core file handler recognizes format, using default"),
	       bfd_get_filename (abfd));
    }
  if (yummy == NULL)
    {
      yummy = core_file_fns;
    }
  return (yummy);
}

/* The default is to reject every core file format we see.  Either
   BFD has to recognize it, or we have to provide a function in the
   core file handler that recognizes it. */

int
default_check_format (bfd *abfd)
{
  return (0);
}

/* Attempt to recognize core file formats that BFD rejects. */

static int
gdb_check_format (bfd *abfd)
{
  struct core_fns *cf;

  for (cf = core_file_fns; cf != NULL; cf = cf->next)
    {
      if (cf->check_format (abfd))
	{
	  return (1);
	}
    }
  return (0);
}

/* Discard all vestiges of any previous core file and mark data and stack
   spaces as empty.  */

static void
core_close (int quitting)
{
  char *name;

  if (core_bfd)
    {
      int pid = ptid_get_pid (inferior_ptid);
      inferior_ptid = null_ptid;	/* Avoid confusion from thread stuff */
      delete_inferior_silent (pid);

      /* Clear out solib state while the bfd is still open. See
         comments in clear_solib in solib.c. */
      clear_solib ();

      xfree (core_data->sections);
      xfree (core_data);
      core_data = NULL;

      name = bfd_get_filename (core_bfd);
      if (!bfd_close (core_bfd))
	warning (_("cannot close \"%s\": %s"),
		 name, bfd_errmsg (bfd_get_error ()));
      xfree (name);
      core_bfd = NULL;
    }
  core_vec = NULL;
  core_gdbarch = NULL;
}

static void
core_close_cleanup (void *ignore)
{
  core_close (0/*ignored*/);
}

/* Look for sections whose names start with `.reg/' so that we can extract the
   list of threads in a core file.  */

static void
add_to_thread_list (bfd *abfd, asection *asect, void *reg_sect_arg)
{
  ptid_t ptid;
  int thread_id;
  asection *reg_sect = (asection *) reg_sect_arg;

  if (strncmp (bfd_section_name (abfd, asect), ".reg/", 5) != 0)
    return;

  thread_id = atoi (bfd_section_name (abfd, asect) + 5);

  if (core_gdbarch
      && gdbarch_core_reg_section_encodes_pid (core_gdbarch))
    {
      uint32_t merged_pid = thread_id;
      ptid = ptid_build (merged_pid & 0xffff,
			 merged_pid >> 16, 0);
    }
  else
    ptid = ptid_build (ptid_get_pid (inferior_ptid), thread_id, 0);

  if (ptid_get_lwp (inferior_ptid) == 0)
    /* The main thread has already been added before getting here, and
       this is the first time we hear about a thread id.  Assume this
       is the main thread.  */
    thread_change_ptid (inferior_ptid, ptid);
  else
    /* Nope, really a new thread.  */
    add_thread (ptid);

/* Warning, Will Robinson, looking at BFD private data! */

  if (reg_sect != NULL
      && asect->filepos == reg_sect->filepos)	/* Did we find .reg? */
    inferior_ptid = ptid;			 /* Yes, make it current */
}

/* This routine opens and sets up the core file bfd.  */

static void
core_open (char *filename, int from_tty)
{
  const char *p;
  int siggy;
  struct cleanup *old_chain;
  char *temp;
  bfd *temp_bfd;
  int scratch_chan;
  int flags;
  int corelow_pid = CORELOW_PID;

  target_preopen (from_tty);
  if (!filename)
    {
      if (core_bfd)
	error (_("No core file specified.  (Use `detach' to stop debugging a core file.)"));
      else
	error (_("No core file specified."));
    }

  filename = tilde_expand (filename);
  if (!IS_ABSOLUTE_PATH(filename))
    {
      temp = concat (current_directory, "/", filename, (char *)NULL);
      xfree (filename);
      filename = temp;
    }

  old_chain = make_cleanup (xfree, filename);

  flags = O_BINARY | O_LARGEFILE;
  if (write_files)
    flags |= O_RDWR;
  else
    flags |= O_RDONLY;
  scratch_chan = open (filename, flags, 0);
  if (scratch_chan < 0)
    perror_with_name (filename);

  temp_bfd = bfd_fopen (filename, gnutarget, 
			write_files ? FOPEN_RUB : FOPEN_RB,
			scratch_chan);
  if (temp_bfd == NULL)
    perror_with_name (filename);

  if (!bfd_check_format (temp_bfd, bfd_core) &&
      !gdb_check_format (temp_bfd))
    {
      /* Do it after the err msg */
      /* FIXME: should be checking for errors from bfd_close (for one thing,
         on error it does not free all the storage associated with the
         bfd).  */
      make_cleanup_bfd_close (temp_bfd);
      error (_("\"%s\" is not a core dump: %s"),
	     filename, bfd_errmsg (bfd_get_error ()));
    }

  /* Looks semi-reasonable.  Toss the old core file and work on the new.  */

  discard_cleanups (old_chain);	/* Don't free filename any more */
  unpush_target (&core_ops);
  core_bfd = temp_bfd;
  old_chain = make_cleanup (core_close_cleanup, 0 /*ignore*/);

  /* FIXME: kettenis/20031023: This is very dangerous.  The
     CORE_GDBARCH that results from this call may very well be
     different from CURRENT_GDBARCH.  However, its methods may only
     work if it is selected as the current architecture, because they
     rely on swapped data (see gdbarch.c).  We should get rid of that
     swapped data.  */
  core_gdbarch = gdbarch_from_bfd (core_bfd);

  /* Find a suitable core file handler to munch on core_bfd */
  core_vec = sniff_core_bfd (core_bfd);

  validate_files ();

  core_data = XZALLOC (struct target_section_table);

  /* Find the data section */
  if (build_section_table (core_bfd,
			   &core_data->sections, &core_data->sections_end))
    error (_("\"%s\": Can't find sections: %s"),
	   bfd_get_filename (core_bfd), bfd_errmsg (bfd_get_error ()));

  /* If we have no exec file, try to set the architecture from the
     core file.  We don't do this unconditionally since an exec file
     typically contains more information that helps us determine the
     architecture than a core file.  */
  if (!exec_bfd)
    set_gdbarch_from_file (core_bfd);

  push_target (&core_ops);
  discard_cleanups (old_chain);

  add_inferior_silent (corelow_pid);

  /* Do this before acknowledging the inferior, so if
     post_create_inferior throws (can happen easilly if you're loading
     a core file with the wrong exec), we aren't left with threads
     from the previous inferior.  */
  init_thread_list ();

  /* Set INFERIOR_PTID early, so an upper layer can rely on it being
     set while in the target_find_new_threads call below.  */
  inferior_ptid = pid_to_ptid (corelow_pid);

  /* Assume ST --- Add a main task.  We'll later detect when we go
     from ST to MT.  */
  add_thread_silent (inferior_ptid);

  /* Need to flush the register cache (and the frame cache) from a
     previous debug session.  If inferior_ptid ends up the same as the
     last debug session --- e.g., b foo; run; gcore core1; step; gcore
     core2; core core1; core core2 --- then there's potential for
     get_current_regcache to return the cached regcache of the
     previous session, and the frame cache being stale.  */
  registers_changed ();

  /* Build up thread list from BFD sections, and possibly set the
     current thread to the .reg/NN section matching the .reg
     section. */
  bfd_map_over_sections (core_bfd, add_to_thread_list,
			 bfd_get_section_by_name (core_bfd, ".reg"));

  post_create_inferior (&core_ops, from_tty);

  /* Now go through the target stack looking for threads since there
     may be a thread_stratum target loaded on top of target core by
     now.  The layer above should claim threads found in the BFD
     sections.  */
  target_find_new_threads ();

  p = bfd_core_file_failing_command (core_bfd);
  if (p)
    printf_filtered (_("Core was generated by `%s'.\n"), p);

  siggy = bfd_core_file_failing_signal (core_bfd);
  if (siggy > 0)
    /* NOTE: target_signal_from_host() converts a target signal value
       into gdb's internal signal value.  Unfortunately gdb's internal
       value is called ``target_signal'' and this function got the
       name ..._from_host(). */
    printf_filtered (_("Program terminated with signal %d, %s.\n"), siggy,
		     target_signal_to_string (
		       (core_gdbarch != NULL) ?
			gdbarch_target_signal_from_host (core_gdbarch, siggy)
			: siggy));

  /* Fetch all registers from core file.  */
  target_fetch_registers (get_current_regcache (), -1);

  /* Now, set up the frame cache, and print the top of stack.  */
  reinit_frame_cache ();
  print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
}

static void
core_detach (struct target_ops *ops, char *args, int from_tty)
{
  if (args)
    error (_("Too many arguments"));
  unpush_target (ops);
  reinit_frame_cache ();
  if (from_tty)
    printf_filtered (_("No core file now.\n"));
}

#ifdef DEPRECATED_IBM6000_TARGET

/* Resize the core memory's section table, by NUM_ADDED.  Returns a
   pointer into the first new slot.  This will not be necessary when
   the rs6000 target is converted to use the standard solib
   framework.  */

struct target_section *
deprecated_core_resize_section_table (int num_added)
{
  int old_count;

  old_count = resize_section_table (core_data, num_added);
  return core_data->sections + old_count;
}

#endif

/* Try to retrieve registers from a section in core_bfd, and supply
   them to core_vec->core_read_registers, as the register set numbered
   WHICH.

   If inferior_ptid's lwp member is zero, do the single-threaded
   thing: look for a section named NAME.  If inferior_ptid's lwp
   member is non-zero, do the multi-threaded thing: look for a section
   named "NAME/LWP", where LWP is the shortest ASCII decimal
   representation of inferior_ptid's lwp member.

   HUMAN_NAME is a human-readable name for the kind of registers the
   NAME section contains, for use in error messages.

   If REQUIRED is non-zero, print an error if the core file doesn't
   have a section by the appropriate name.  Otherwise, just do nothing.  */

static void
get_core_register_section (struct regcache *regcache,
			   char *name,
			   int which,
			   char *human_name,
			   int required)
{
  static char *section_name = NULL;
  struct bfd_section *section;
  bfd_size_type size;
  char *contents;

  xfree (section_name);

  if (core_gdbarch
      && gdbarch_core_reg_section_encodes_pid (core_gdbarch))
    {
      uint32_t merged_pid;

      merged_pid = ptid_get_lwp (inferior_ptid);
      merged_pid = merged_pid << 16 | ptid_get_pid (inferior_ptid);

      section_name = xstrprintf ("%s/%s", name, plongest (merged_pid));
    }
  else if (ptid_get_lwp (inferior_ptid))
    section_name = xstrprintf ("%s/%ld", name, ptid_get_lwp (inferior_ptid));
  else
    section_name = xstrdup (name);

  section = bfd_get_section_by_name (core_bfd, section_name);
  if (! section)
    {
      if (required)
	warning (_("Couldn't find %s registers in core file."), human_name);
      return;
    }

  size = bfd_section_size (core_bfd, section);
  contents = alloca (size);
  if (! bfd_get_section_contents (core_bfd, section, contents,
				  (file_ptr) 0, size))
    {
      warning (_("Couldn't read %s registers from `%s' section in core file."),
	       human_name, name);
      return;
    }

  if (core_gdbarch && gdbarch_regset_from_core_section_p (core_gdbarch))
    {
      const struct regset *regset;

      regset = gdbarch_regset_from_core_section (core_gdbarch, name, size);
      if (regset == NULL)
	{
	  if (required)
	    warning (_("Couldn't recognize %s registers in core file."),
		     human_name);
	  return;
	}

      regset->supply_regset (regset, regcache, -1, contents, size);
      return;
    }

  gdb_assert (core_vec);
  core_vec->core_read_registers (regcache, contents, size, which,
				 ((CORE_ADDR)
				  bfd_section_vma (core_bfd, section)));
}


/* Get the registers out of a core file.  This is the machine-
   independent part.  Fetch_core_registers is the machine-dependent
   part, typically implemented in the xm-file for each architecture.  */

/* We just get all the registers, so we don't use regno.  */

static void
get_core_registers (struct target_ops *ops,
		    struct regcache *regcache, int regno)
{
  int i;

  if (!(core_gdbarch && gdbarch_regset_from_core_section_p (core_gdbarch))
      && (core_vec == NULL || core_vec->core_read_registers == NULL))
    {
      fprintf_filtered (gdb_stderr,
		     "Can't fetch registers from this type of core file\n");
      return;
    }

  get_core_register_section (regcache,
			     ".reg", 0, "general-purpose", 1);
  get_core_register_section (regcache,
			     ".reg2", 2, "floating-point", 0);
  get_core_register_section (regcache,
			     ".reg-xfp", 3, "extended floating-point", 0);
  get_core_register_section (regcache,
  			     ".reg-ppc-vmx", 3, "ppc Altivec", 0);
  get_core_register_section (regcache,
			     ".reg-ppc-vsx", 4, "POWER7 VSX", 0);

  /* Supply dummy value for all registers not found in the core.  */
  for (i = 0; i < gdbarch_num_regs (get_regcache_arch (regcache)); i++)
    if (!regcache_valid_p (regcache, i))
      regcache_raw_supply (regcache, i, NULL);
}

static void
core_files_info (struct target_ops *t)
{
  print_section_info (core_data, core_bfd);
}

struct spuid_list
{
  gdb_byte *buf;
  ULONGEST offset;
  LONGEST len;
  ULONGEST pos;
  ULONGEST written;
};

static void
add_to_spuid_list (bfd *abfd, asection *asect, void *list_p)
{
  struct spuid_list *list = list_p;
  enum bfd_endian byte_order
    = bfd_big_endian (abfd)? BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE;
  int fd, pos = 0;

  sscanf (bfd_section_name (abfd, asect), "SPU/%d/regs%n", &fd, &pos);
  if (pos == 0)
    return;

  if (list->pos >= list->offset && list->pos + 4 <= list->offset + list->len)
    {
      store_unsigned_integer (list->buf + list->pos - list->offset,
			      4, byte_order, fd);
      list->written += 4;
    }
  list->pos += 4;
}

static LONGEST
core_xfer_partial (struct target_ops *ops, enum target_object object,
		   const char *annex, gdb_byte *readbuf,
		   const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
{
  switch (object)
    {
    case TARGET_OBJECT_MEMORY:
      return section_table_xfer_memory_partial (readbuf, writebuf,
						offset, len,
						core_data->sections,
						core_data->sections_end,
						NULL);

    case TARGET_OBJECT_AUXV:
      if (readbuf)
	{
	  /* When the aux vector is stored in core file, BFD
	     represents this with a fake section called ".auxv".  */

	  struct bfd_section *section;
	  bfd_size_type size;
	  char *contents;

	  section = bfd_get_section_by_name (core_bfd, ".auxv");
	  if (section == NULL)
	    return -1;

	  size = bfd_section_size (core_bfd, section);
	  if (offset >= size)
	    return 0;
	  size -= offset;
	  if (size > len)
	    size = len;
	  if (size > 0
	      && !bfd_get_section_contents (core_bfd, section, readbuf,
					    (file_ptr) offset, size))
	    {
	      warning (_("Couldn't read NT_AUXV note in core file."));
	      return -1;
	    }

	  return size;
	}
      return -1;

    case TARGET_OBJECT_WCOOKIE:
      if (readbuf)
	{
	  /* When the StackGhost cookie is stored in core file, BFD
	     represents this with a fake section called ".wcookie".  */

	  struct bfd_section *section;
	  bfd_size_type size;
	  char *contents;

	  section = bfd_get_section_by_name (core_bfd, ".wcookie");
	  if (section == NULL)
	    return -1;

	  size = bfd_section_size (core_bfd, section);
	  if (offset >= size)
	    return 0;
	  size -= offset;
	  if (size > len)
	    size = len;
	  if (size > 0
	      && !bfd_get_section_contents (core_bfd, section, readbuf,
					    (file_ptr) offset, size))
	    {
	      warning (_("Couldn't read StackGhost cookie in core file."));
	      return -1;
	    }

	  return size;
	}
      return -1;

    case TARGET_OBJECT_LIBRARIES:
      if (core_gdbarch
	  && gdbarch_core_xfer_shared_libraries_p (core_gdbarch))
	{
	  if (writebuf)
	    return -1;
	  return
	    gdbarch_core_xfer_shared_libraries (core_gdbarch,
						readbuf, offset, len);
	}
      /* FALL THROUGH */

    case TARGET_OBJECT_SPU:
      if (readbuf && annex)
	{
	  /* When the SPU contexts are stored in a core file, BFD
	     represents this with a fake section called "SPU/<annex>".  */

	  struct bfd_section *section;
	  bfd_size_type size;
	  char *contents;

	  char sectionstr[100];
	  xsnprintf (sectionstr, sizeof sectionstr, "SPU/%s", annex);

	  section = bfd_get_section_by_name (core_bfd, sectionstr);
	  if (section == NULL)
	    return -1;

	  size = bfd_section_size (core_bfd, section);
	  if (offset >= size)
	    return 0;
	  size -= offset;
	  if (size > len)
	    size = len;
	  if (size > 0
	      && !bfd_get_section_contents (core_bfd, section, readbuf,
					    (file_ptr) offset, size))
	    {
	      warning (_("Couldn't read SPU section in core file."));
	      return -1;
	    }

	  return size;
	}
      else if (readbuf)
	{
	  /* NULL annex requests list of all present spuids.  */
	  struct spuid_list list;
	  list.buf = readbuf;
	  list.offset = offset;
	  list.len = len;
	  list.pos = 0;
	  list.written = 0;
	  bfd_map_over_sections (core_bfd, add_to_spuid_list, &list);
	  return list.written;
	}
      return -1;

    default:
      if (ops->beneath != NULL)
	return ops->beneath->to_xfer_partial (ops->beneath, object, annex,
					      readbuf, writebuf, offset, len);
      return -1;
    }
}


/* If mourn is being called in all the right places, this could be say
   `gdb internal error' (since generic_mourn calls breakpoint_init_inferior).  */

static int
ignore (struct gdbarch *gdbarch, struct bp_target_info *bp_tgt)
{
  return 0;
}


/* Okay, let's be honest: threads gleaned from a core file aren't
   exactly lively, are they?  On the other hand, if we don't claim
   that each & every one is alive, then we don't get any of them
   to appear in an "info thread" command, which is quite a useful
   behaviour.
 */
static int
core_thread_alive (struct target_ops *ops, ptid_t ptid)
{
  return 1;
}

/* Ask the current architecture what it knows about this core file.
   That will be used, in turn, to pick a better architecture.  This
   wrapper could be avoided if targets got a chance to specialize
   core_ops.  */

static const struct target_desc *
core_read_description (struct target_ops *target)
{
  if (core_gdbarch && gdbarch_core_read_description_p (core_gdbarch))
    return gdbarch_core_read_description (core_gdbarch, target, core_bfd);

  return NULL;
}

static char *
core_pid_to_str (struct target_ops *ops, ptid_t ptid)
{
  static char buf[64];

  if (core_gdbarch
      && gdbarch_core_pid_to_str_p (core_gdbarch))
    {
      char *ret = gdbarch_core_pid_to_str (core_gdbarch, ptid);
      if (ret != NULL)
	return ret;
    }

  if (ptid_get_lwp (ptid) == 0)
    xsnprintf (buf, sizeof buf, "<main task>");
  else
    xsnprintf (buf, sizeof buf, "Thread %ld", ptid_get_lwp (ptid));

  return buf;
}

static int
core_has_memory (struct target_ops *ops)
{
  return (core_bfd != NULL);
}

static int
core_has_stack (struct target_ops *ops)
{
  return (core_bfd != NULL);
}

static int
core_has_registers (struct target_ops *ops)
{
  return (core_bfd != NULL);
}

/* Fill in core_ops with its defined operations and properties.  */

static void
init_core_ops (void)
{
  core_ops.to_shortname = "core";
  core_ops.to_longname = "Local core dump file";
  core_ops.to_doc =
    "Use a core file as a target.  Specify the filename of the core file.";
  core_ops.to_open = core_open;
  core_ops.to_close = core_close;
  core_ops.to_attach = find_default_attach;
  core_ops.to_detach = core_detach;
  core_ops.to_fetch_registers = get_core_registers;
  core_ops.to_xfer_partial = core_xfer_partial;
  core_ops.to_files_info = core_files_info;
  core_ops.to_insert_breakpoint = ignore;
  core_ops.to_remove_breakpoint = ignore;
  core_ops.to_create_inferior = find_default_create_inferior;
  core_ops.to_thread_alive = core_thread_alive;
  core_ops.to_read_description = core_read_description;
  core_ops.to_pid_to_str = core_pid_to_str;
  core_ops.to_stratum = core_stratum;
  core_ops.to_has_memory = core_has_memory;
  core_ops.to_has_stack = core_has_stack;
  core_ops.to_has_registers = core_has_registers;
  core_ops.to_magic = OPS_MAGIC;
}

void
_initialize_corelow (void)
{
  init_core_ops ();

  add_target (&core_ops);
}