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[/] [openrisc/] [trunk/] [gnu-src/] [gdb-6.8/] [gdb/] [gdbserver/] [linux-low.c] - Blame information for rev 157

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1 24 jeremybenn
/* Low level interface to ptrace, for the remote server for GDB.
2
   Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
3
   2006, 2007, 2008 Free Software Foundation, Inc.
4
 
5
   This file is part of GDB.
6
 
7
   This program is free software; you can redistribute it and/or modify
8
   it under the terms of the GNU General Public License as published by
9
   the Free Software Foundation; either version 3 of the License, or
10
   (at your option) any later version.
11
 
12
   This program is distributed in the hope that it will be useful,
13
   but WITHOUT ANY WARRANTY; without even the implied warranty of
14
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15
   GNU General Public License for more details.
16
 
17
   You should have received a copy of the GNU General Public License
18
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
19
 
20
#include "server.h"
21
#include "linux-low.h"
22
 
23
#include <sys/wait.h>
24
#include <stdio.h>
25
#include <sys/param.h>
26
#include <sys/dir.h>
27
#include <sys/ptrace.h>
28
#include <sys/user.h>
29
#include <signal.h>
30
#include <sys/ioctl.h>
31
#include <fcntl.h>
32
#include <string.h>
33
#include <stdlib.h>
34
#include <unistd.h>
35
#include <errno.h>
36
#include <sys/syscall.h>
37
#include <sched.h>
38
 
39
#ifndef PTRACE_GETSIGINFO
40
# define PTRACE_GETSIGINFO 0x4202
41
# define PTRACE_SETSIGINFO 0x4203
42
#endif
43
 
44
#ifndef O_LARGEFILE
45
#define O_LARGEFILE 0
46
#endif
47
 
48
/* If the system headers did not provide the constants, hard-code the normal
49
   values.  */
50
#ifndef PTRACE_EVENT_FORK
51
 
52
#define PTRACE_SETOPTIONS       0x4200
53
#define PTRACE_GETEVENTMSG      0x4201
54
 
55
/* options set using PTRACE_SETOPTIONS */
56
#define PTRACE_O_TRACESYSGOOD   0x00000001
57
#define PTRACE_O_TRACEFORK      0x00000002
58
#define PTRACE_O_TRACEVFORK     0x00000004
59
#define PTRACE_O_TRACECLONE     0x00000008
60
#define PTRACE_O_TRACEEXEC      0x00000010
61
#define PTRACE_O_TRACEVFORKDONE 0x00000020
62
#define PTRACE_O_TRACEEXIT      0x00000040
63
 
64
/* Wait extended result codes for the above trace options.  */
65
#define PTRACE_EVENT_FORK       1
66
#define PTRACE_EVENT_VFORK      2
67
#define PTRACE_EVENT_CLONE      3
68
#define PTRACE_EVENT_EXEC       4
69
#define PTRACE_EVENT_VFORK_DONE 5
70
#define PTRACE_EVENT_EXIT       6
71
 
72
#endif /* PTRACE_EVENT_FORK */
73
 
74
/* We can't always assume that this flag is available, but all systems
75
   with the ptrace event handlers also have __WALL, so it's safe to use
76
   in some contexts.  */
77
#ifndef __WALL
78
#define __WALL          0x40000000 /* Wait for any child.  */
79
#endif
80
 
81
#ifdef __UCLIBC__
82
#if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__))
83
#define HAS_NOMMU
84
#endif
85
#endif
86
 
87
/* ``all_threads'' is keyed by the LWP ID, which we use as the GDB protocol
88
   representation of the thread ID.
89
 
90
   ``all_processes'' is keyed by the process ID - which on Linux is (presently)
91
   the same as the LWP ID.  */
92
 
93
struct inferior_list all_processes;
94
 
95
/* A list of all unknown processes which receive stop signals.  Some other
96
   process will presumably claim each of these as forked children
97
   momentarily.  */
98
 
99
struct inferior_list stopped_pids;
100
 
101
/* FIXME this is a bit of a hack, and could be removed.  */
102
int stopping_threads;
103
 
104
/* FIXME make into a target method?  */
105
int using_threads = 1;
106
static int thread_db_active;
107
 
108
static int must_set_ptrace_flags;
109
 
110
static void linux_resume_one_process (struct inferior_list_entry *entry,
111
                                      int step, int signal, siginfo_t *info);
112
static void linux_resume (struct thread_resume *resume_info);
113
static void stop_all_processes (void);
114
static int linux_wait_for_event (struct thread_info *child);
115
static int check_removed_breakpoint (struct process_info *event_child);
116
static void *add_process (unsigned long pid);
117
 
118
struct pending_signals
119
{
120
  int signal;
121
  siginfo_t info;
122
  struct pending_signals *prev;
123
};
124
 
125
#define PTRACE_ARG3_TYPE long
126
#define PTRACE_XFER_TYPE long
127
 
128
#ifdef HAVE_LINUX_REGSETS
129
static int use_regsets_p = 1;
130
#endif
131
 
132
#define pid_of(proc) ((proc)->head.id)
133
 
134
/* FIXME: Delete eventually.  */
135
#define inferior_pid (pid_of (get_thread_process (current_inferior)))
136
 
137
static void
138
handle_extended_wait (struct process_info *event_child, int wstat)
139
{
140
  int event = wstat >> 16;
141
  struct process_info *new_process;
142
 
143
  if (event == PTRACE_EVENT_CLONE)
144
    {
145
      unsigned long new_pid;
146
      int ret, status;
147
 
148
      ptrace (PTRACE_GETEVENTMSG, inferior_pid, 0, &new_pid);
149
 
150
      /* If we haven't already seen the new PID stop, wait for it now.  */
151
      if (! pull_pid_from_list (&stopped_pids, new_pid))
152
        {
153
          /* The new child has a pending SIGSTOP.  We can't affect it until it
154
             hits the SIGSTOP, but we're already attached.  */
155
 
156
          do {
157
            ret = waitpid (new_pid, &status, __WALL);
158
          } while (ret == -1 && errno == EINTR);
159
 
160
          if (ret == -1)
161
            perror_with_name ("waiting for new child");
162
          else if (ret != new_pid)
163
            warning ("wait returned unexpected PID %d", ret);
164
          else if (!WIFSTOPPED (status))
165
            warning ("wait returned unexpected status 0x%x", status);
166
        }
167
 
168
      ptrace (PTRACE_SETOPTIONS, new_pid, 0, PTRACE_O_TRACECLONE);
169
 
170
      new_process = (struct process_info *) add_process (new_pid);
171
      add_thread (new_pid, new_process, new_pid);
172
      new_thread_notify (thread_id_to_gdb_id (new_process->lwpid));
173
 
174
      /* Normally we will get the pending SIGSTOP.  But in some cases
175
         we might get another signal delivered to the group first.
176
         If we do, be sure not to lose it.  */
177
      if (WSTOPSIG (status) == SIGSTOP)
178
        {
179
          if (stopping_threads)
180
            new_process->stopped = 1;
181
          else
182
            ptrace (PTRACE_CONT, new_pid, 0, 0);
183
        }
184
      else
185
        {
186
          new_process->stop_expected = 1;
187
          if (stopping_threads)
188
            {
189
              new_process->stopped = 1;
190
              new_process->status_pending_p = 1;
191
              new_process->status_pending = status;
192
            }
193
          else
194
            /* Pass the signal on.  This is what GDB does - except
195
               shouldn't we really report it instead?  */
196
            ptrace (PTRACE_CONT, new_pid, 0, WSTOPSIG (status));
197
        }
198
 
199
      /* Always resume the current thread.  If we are stopping
200
         threads, it will have a pending SIGSTOP; we may as well
201
         collect it now.  */
202
      linux_resume_one_process (&event_child->head,
203
                                event_child->stepping, 0, NULL);
204
    }
205
}
206
 
207
/* This function should only be called if the process got a SIGTRAP.
208
   The SIGTRAP could mean several things.
209
 
210
   On i386, where decr_pc_after_break is non-zero:
211
   If we were single-stepping this process using PTRACE_SINGLESTEP,
212
   we will get only the one SIGTRAP (even if the instruction we
213
   stepped over was a breakpoint).  The value of $eip will be the
214
   next instruction.
215
   If we continue the process using PTRACE_CONT, we will get a
216
   SIGTRAP when we hit a breakpoint.  The value of $eip will be
217
   the instruction after the breakpoint (i.e. needs to be
218
   decremented).  If we report the SIGTRAP to GDB, we must also
219
   report the undecremented PC.  If we cancel the SIGTRAP, we
220
   must resume at the decremented PC.
221
 
222
   (Presumably, not yet tested) On a non-decr_pc_after_break machine
223
   with hardware or kernel single-step:
224
   If we single-step over a breakpoint instruction, our PC will
225
   point at the following instruction.  If we continue and hit a
226
   breakpoint instruction, our PC will point at the breakpoint
227
   instruction.  */
228
 
229
static CORE_ADDR
230
get_stop_pc (void)
231
{
232
  CORE_ADDR stop_pc = (*the_low_target.get_pc) ();
233
 
234
  if (get_thread_process (current_inferior)->stepping)
235
    return stop_pc;
236
  else
237
    return stop_pc - the_low_target.decr_pc_after_break;
238
}
239
 
240
static void *
241
add_process (unsigned long pid)
242
{
243
  struct process_info *process;
244
 
245
  process = (struct process_info *) malloc (sizeof (*process));
246
  memset (process, 0, sizeof (*process));
247
 
248
  process->head.id = pid;
249
  process->lwpid = pid;
250
 
251
  add_inferior_to_list (&all_processes, &process->head);
252
 
253
  return process;
254
}
255
 
256
/* Start an inferior process and returns its pid.
257
   ALLARGS is a vector of program-name and args. */
258
 
259
static int
260
linux_create_inferior (char *program, char **allargs)
261
{
262
  void *new_process;
263
  int pid;
264
 
265
#if defined(__UCLIBC__) && defined(HAS_NOMMU)
266
  pid = vfork ();
267
#else
268
  pid = fork ();
269
#endif
270
  if (pid < 0)
271
    perror_with_name ("fork");
272
 
273
  if (pid == 0)
274
    {
275
      ptrace (PTRACE_TRACEME, 0, 0, 0);
276
 
277
      signal (__SIGRTMIN + 1, SIG_DFL);
278
 
279
      setpgid (0, 0);
280
 
281
      execv (program, allargs);
282
      if (errno == ENOENT)
283
        execvp (program, allargs);
284
 
285
      fprintf (stderr, "Cannot exec %s: %s.\n", program,
286
               strerror (errno));
287
      fflush (stderr);
288
      _exit (0177);
289
    }
290
 
291
  new_process = add_process (pid);
292
  add_thread (pid, new_process, pid);
293
  must_set_ptrace_flags = 1;
294
 
295
  return pid;
296
}
297
 
298
/* Attach to an inferior process.  */
299
 
300
void
301
linux_attach_lwp (unsigned long pid)
302
{
303
  struct process_info *new_process;
304
 
305
  if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
306
    {
307
      if (all_threads.head != NULL)
308
        {
309
          /* If we fail to attach to an LWP, just warn.  */
310
          fprintf (stderr, "Cannot attach to process %ld: %s (%d)\n", pid,
311
                   strerror (errno), errno);
312
          fflush (stderr);
313
          return;
314
        }
315
      else
316
        /* If we fail to attach to a process, report an error.  */
317
        error ("Cannot attach to process %ld: %s (%d)\n", pid,
318
               strerror (errno), errno);
319
    }
320
 
321
  ptrace (PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACECLONE);
322
 
323
  new_process = (struct process_info *) add_process (pid);
324
  add_thread (pid, new_process, pid);
325
  new_thread_notify (thread_id_to_gdb_id (new_process->lwpid));
326
 
327
  /* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH
328
     brings it to a halt.  We should ignore that SIGSTOP and resume the process
329
     (unless this is the first process, in which case the flag will be cleared
330
     in linux_attach).
331
 
332
     On the other hand, if we are currently trying to stop all threads, we
333
     should treat the new thread as if we had sent it a SIGSTOP.  This works
334
     because we are guaranteed that add_process added us to the end of the
335
     list, and so the new thread has not yet reached wait_for_sigstop (but
336
     will).  */
337
  if (! stopping_threads)
338
    new_process->stop_expected = 1;
339
}
340
 
341
int
342
linux_attach (unsigned long pid)
343
{
344
  struct process_info *process;
345
 
346
  linux_attach_lwp (pid);
347
 
348
  /* Don't ignore the initial SIGSTOP if we just attached to this process.
349
     It will be collected by wait shortly.  */
350
  process = (struct process_info *) find_inferior_id (&all_processes, pid);
351
  process->stop_expected = 0;
352
 
353
  return 0;
354
}
355
 
356
/* Kill the inferior process.  Make us have no inferior.  */
357
 
358
static void
359
linux_kill_one_process (struct inferior_list_entry *entry)
360
{
361
  struct thread_info *thread = (struct thread_info *) entry;
362
  struct process_info *process = get_thread_process (thread);
363
  int wstat;
364
 
365
  /* We avoid killing the first thread here, because of a Linux kernel (at
366
     least 2.6.0-test7 through 2.6.8-rc4) bug; if we kill the parent before
367
     the children get a chance to be reaped, it will remain a zombie
368
     forever.  */
369
  if (entry == all_threads.head)
370
    return;
371
 
372
  do
373
    {
374
      ptrace (PTRACE_KILL, pid_of (process), 0, 0);
375
 
376
      /* Make sure it died.  The loop is most likely unnecessary.  */
377
      wstat = linux_wait_for_event (thread);
378
    } while (WIFSTOPPED (wstat));
379
}
380
 
381
static void
382
linux_kill (void)
383
{
384
  struct thread_info *thread = (struct thread_info *) all_threads.head;
385
  struct process_info *process;
386
  int wstat;
387
 
388
  if (thread == NULL)
389
    return;
390
 
391
  for_each_inferior (&all_threads, linux_kill_one_process);
392
 
393
  /* See the comment in linux_kill_one_process.  We did not kill the first
394
     thread in the list, so do so now.  */
395
  process = get_thread_process (thread);
396
  do
397
    {
398
      ptrace (PTRACE_KILL, pid_of (process), 0, 0);
399
 
400
      /* Make sure it died.  The loop is most likely unnecessary.  */
401
      wstat = linux_wait_for_event (thread);
402
    } while (WIFSTOPPED (wstat));
403
 
404
  clear_inferiors ();
405
  free (all_processes.head);
406
  all_processes.head = all_processes.tail = NULL;
407
}
408
 
409
static void
410
linux_detach_one_process (struct inferior_list_entry *entry)
411
{
412
  struct thread_info *thread = (struct thread_info *) entry;
413
  struct process_info *process = get_thread_process (thread);
414
 
415
  /* Make sure the process isn't stopped at a breakpoint that's
416
     no longer there.  */
417
  check_removed_breakpoint (process);
418
 
419
  /* If this process is stopped but is expecting a SIGSTOP, then make
420
     sure we take care of that now.  This isn't absolutely guaranteed
421
     to collect the SIGSTOP, but is fairly likely to.  */
422
  if (process->stop_expected)
423
    {
424
      /* Clear stop_expected, so that the SIGSTOP will be reported.  */
425
      process->stop_expected = 0;
426
      if (process->stopped)
427
        linux_resume_one_process (&process->head, 0, 0, NULL);
428
      linux_wait_for_event (thread);
429
    }
430
 
431
  /* Flush any pending changes to the process's registers.  */
432
  regcache_invalidate_one ((struct inferior_list_entry *)
433
                           get_process_thread (process));
434
 
435
  /* Finally, let it resume.  */
436
  ptrace (PTRACE_DETACH, pid_of (process), 0, 0);
437
}
438
 
439
static int
440
linux_detach (void)
441
{
442
  delete_all_breakpoints ();
443
  for_each_inferior (&all_threads, linux_detach_one_process);
444
  clear_inferiors ();
445
  free (all_processes.head);
446
  all_processes.head = all_processes.tail = NULL;
447
  return 0;
448
}
449
 
450
static void
451
linux_join (void)
452
{
453
  extern unsigned long signal_pid;
454
  int status, ret;
455
 
456
  do {
457
    ret = waitpid (signal_pid, &status, 0);
458
    if (WIFEXITED (status) || WIFSIGNALED (status))
459
      break;
460
  } while (ret != -1 || errno != ECHILD);
461
}
462
 
463
/* Return nonzero if the given thread is still alive.  */
464
static int
465
linux_thread_alive (unsigned long lwpid)
466
{
467
  if (find_inferior_id (&all_threads, lwpid) != NULL)
468
    return 1;
469
  else
470
    return 0;
471
}
472
 
473
/* Return nonzero if this process stopped at a breakpoint which
474
   no longer appears to be inserted.  Also adjust the PC
475
   appropriately to resume where the breakpoint used to be.  */
476
static int
477
check_removed_breakpoint (struct process_info *event_child)
478
{
479
  CORE_ADDR stop_pc;
480
  struct thread_info *saved_inferior;
481
 
482
  if (event_child->pending_is_breakpoint == 0)
483
    return 0;
484
 
485
  if (debug_threads)
486
    fprintf (stderr, "Checking for breakpoint in process %ld.\n",
487
             event_child->lwpid);
488
 
489
  saved_inferior = current_inferior;
490
  current_inferior = get_process_thread (event_child);
491
 
492
  stop_pc = get_stop_pc ();
493
 
494
  /* If the PC has changed since we stopped, then we shouldn't do
495
     anything.  This happens if, for instance, GDB handled the
496
     decr_pc_after_break subtraction itself.  */
497
  if (stop_pc != event_child->pending_stop_pc)
498
    {
499
      if (debug_threads)
500
        fprintf (stderr, "Ignoring, PC was changed.  Old PC was 0x%08llx\n",
501
                 event_child->pending_stop_pc);
502
 
503
      event_child->pending_is_breakpoint = 0;
504
      current_inferior = saved_inferior;
505
      return 0;
506
    }
507
 
508
  /* If the breakpoint is still there, we will report hitting it.  */
509
  if ((*the_low_target.breakpoint_at) (stop_pc))
510
    {
511
      if (debug_threads)
512
        fprintf (stderr, "Ignoring, breakpoint is still present.\n");
513
      current_inferior = saved_inferior;
514
      return 0;
515
    }
516
 
517
  if (debug_threads)
518
    fprintf (stderr, "Removed breakpoint.\n");
519
 
520
  /* For decr_pc_after_break targets, here is where we perform the
521
     decrement.  We go immediately from this function to resuming,
522
     and can not safely call get_stop_pc () again.  */
523
  if (the_low_target.set_pc != NULL)
524
    (*the_low_target.set_pc) (stop_pc);
525
 
526
  /* We consumed the pending SIGTRAP.  */
527
  event_child->pending_is_breakpoint = 0;
528
  event_child->status_pending_p = 0;
529
  event_child->status_pending = 0;
530
 
531
  current_inferior = saved_inferior;
532
  return 1;
533
}
534
 
535
/* Return 1 if this process has an interesting status pending.  This function
536
   may silently resume an inferior process.  */
537
static int
538
status_pending_p (struct inferior_list_entry *entry, void *dummy)
539
{
540
  struct process_info *process = (struct process_info *) entry;
541
 
542
  if (process->status_pending_p)
543
    if (check_removed_breakpoint (process))
544
      {
545
        /* This thread was stopped at a breakpoint, and the breakpoint
546
           is now gone.  We were told to continue (or step...) all threads,
547
           so GDB isn't trying to single-step past this breakpoint.
548
           So instead of reporting the old SIGTRAP, pretend we got to
549
           the breakpoint just after it was removed instead of just
550
           before; resume the process.  */
551
        linux_resume_one_process (&process->head, 0, 0, NULL);
552
        return 0;
553
      }
554
 
555
  return process->status_pending_p;
556
}
557
 
558
static void
559
linux_wait_for_process (struct process_info **childp, int *wstatp)
560
{
561
  int ret;
562
  int to_wait_for = -1;
563
 
564
  if (*childp != NULL)
565
    to_wait_for = (*childp)->lwpid;
566
 
567
retry:
568
  while (1)
569
    {
570
      ret = waitpid (to_wait_for, wstatp, WNOHANG);
571
 
572
      if (ret == -1)
573
        {
574
          if (errno != ECHILD)
575
            perror_with_name ("waitpid");
576
        }
577
      else if (ret > 0)
578
        break;
579
 
580
      ret = waitpid (to_wait_for, wstatp, WNOHANG | __WCLONE);
581
 
582
      if (ret == -1)
583
        {
584
          if (errno != ECHILD)
585
            perror_with_name ("waitpid (WCLONE)");
586
        }
587
      else if (ret > 0)
588
        break;
589
 
590
      usleep (1000);
591
    }
592
 
593
  if (debug_threads
594
      && (!WIFSTOPPED (*wstatp)
595
          || (WSTOPSIG (*wstatp) != 32
596
              && WSTOPSIG (*wstatp) != 33)))
597
    fprintf (stderr, "Got an event from %d (%x)\n", ret, *wstatp);
598
 
599
  if (to_wait_for == -1)
600
    *childp = (struct process_info *) find_inferior_id (&all_processes, ret);
601
 
602
  /* If we didn't find a process, one of two things presumably happened:
603
     - A process we started and then detached from has exited.  Ignore it.
604
     - A process we are controlling has forked and the new child's stop
605
     was reported to us by the kernel.  Save its PID.  */
606
  if (*childp == NULL && WIFSTOPPED (*wstatp))
607
    {
608
      add_pid_to_list (&stopped_pids, ret);
609
      goto retry;
610
    }
611
  else if (*childp == NULL)
612
    goto retry;
613
 
614
  (*childp)->stopped = 1;
615
  (*childp)->pending_is_breakpoint = 0;
616
 
617
  (*childp)->last_status = *wstatp;
618
 
619
  if (debug_threads
620
      && WIFSTOPPED (*wstatp))
621
    {
622
      current_inferior = (struct thread_info *)
623
        find_inferior_id (&all_threads, (*childp)->lwpid);
624
      /* For testing only; i386_stop_pc prints out a diagnostic.  */
625
      if (the_low_target.get_pc != NULL)
626
        get_stop_pc ();
627
    }
628
}
629
 
630
static int
631
linux_wait_for_event (struct thread_info *child)
632
{
633
  CORE_ADDR stop_pc;
634
  struct process_info *event_child;
635
  int wstat;
636
  int bp_status;
637
 
638
  /* Check for a process with a pending status.  */
639
  /* It is possible that the user changed the pending task's registers since
640
     it stopped.  We correctly handle the change of PC if we hit a breakpoint
641
     (in check_removed_breakpoint); signals should be reported anyway.  */
642
  if (child == NULL)
643
    {
644
      event_child = (struct process_info *)
645
        find_inferior (&all_processes, status_pending_p, NULL);
646
      if (debug_threads && event_child)
647
        fprintf (stderr, "Got a pending child %ld\n", event_child->lwpid);
648
    }
649
  else
650
    {
651
      event_child = get_thread_process (child);
652
      if (event_child->status_pending_p
653
          && check_removed_breakpoint (event_child))
654
        event_child = NULL;
655
    }
656
 
657
  if (event_child != NULL)
658
    {
659
      if (event_child->status_pending_p)
660
        {
661
          if (debug_threads)
662
            fprintf (stderr, "Got an event from pending child %ld (%04x)\n",
663
                     event_child->lwpid, event_child->status_pending);
664
          wstat = event_child->status_pending;
665
          event_child->status_pending_p = 0;
666
          event_child->status_pending = 0;
667
          current_inferior = get_process_thread (event_child);
668
          return wstat;
669
        }
670
    }
671
 
672
  /* We only enter this loop if no process has a pending wait status.  Thus
673
     any action taken in response to a wait status inside this loop is
674
     responding as soon as we detect the status, not after any pending
675
     events.  */
676
  while (1)
677
    {
678
      if (child == NULL)
679
        event_child = NULL;
680
      else
681
        event_child = get_thread_process (child);
682
 
683
      linux_wait_for_process (&event_child, &wstat);
684
 
685
      if (event_child == NULL)
686
        error ("event from unknown child");
687
 
688
      current_inferior = (struct thread_info *)
689
        find_inferior_id (&all_threads, event_child->lwpid);
690
 
691
      /* Check for thread exit.  */
692
      if (! WIFSTOPPED (wstat))
693
        {
694
          if (debug_threads)
695
            fprintf (stderr, "LWP %ld exiting\n", event_child->head.id);
696
 
697
          /* If the last thread is exiting, just return.  */
698
          if (all_threads.head == all_threads.tail)
699
            return wstat;
700
 
701
          dead_thread_notify (thread_id_to_gdb_id (event_child->lwpid));
702
 
703
          remove_inferior (&all_processes, &event_child->head);
704
          free (event_child);
705
          remove_thread (current_inferior);
706
          current_inferior = (struct thread_info *) all_threads.head;
707
 
708
          /* If we were waiting for this particular child to do something...
709
             well, it did something.  */
710
          if (child != NULL)
711
            return wstat;
712
 
713
          /* Wait for a more interesting event.  */
714
          continue;
715
        }
716
 
717
      if (WIFSTOPPED (wstat)
718
          && WSTOPSIG (wstat) == SIGSTOP
719
          && event_child->stop_expected)
720
        {
721
          if (debug_threads)
722
            fprintf (stderr, "Expected stop.\n");
723
          event_child->stop_expected = 0;
724
          linux_resume_one_process (&event_child->head,
725
                                    event_child->stepping, 0, NULL);
726
          continue;
727
        }
728
 
729
      if (WIFSTOPPED (wstat) && WSTOPSIG (wstat) == SIGTRAP
730
          && wstat >> 16 != 0)
731
        {
732
          handle_extended_wait (event_child, wstat);
733
          continue;
734
        }
735
 
736
      /* If GDB is not interested in this signal, don't stop other
737
         threads, and don't report it to GDB.  Just resume the
738
         inferior right away.  We do this for threading-related
739
         signals as well as any that GDB specifically requested we
740
         ignore.  But never ignore SIGSTOP if we sent it ourselves,
741
         and do not ignore signals when stepping - they may require
742
         special handling to skip the signal handler.  */
743
      /* FIXME drow/2002-06-09: Get signal numbers from the inferior's
744
         thread library?  */
745
      if (WIFSTOPPED (wstat)
746
          && !event_child->stepping
747
          && (
748
#ifdef USE_THREAD_DB
749
              (thread_db_active && (WSTOPSIG (wstat) == __SIGRTMIN
750
                                    || WSTOPSIG (wstat) == __SIGRTMIN + 1))
751
              ||
752
#endif
753
              (pass_signals[target_signal_from_host (WSTOPSIG (wstat))]
754
               && (WSTOPSIG (wstat) != SIGSTOP || !stopping_threads))))
755
        {
756
          siginfo_t info, *info_p;
757
 
758
          if (debug_threads)
759
            fprintf (stderr, "Ignored signal %d for LWP %ld.\n",
760
                     WSTOPSIG (wstat), event_child->head.id);
761
 
762
          if (ptrace (PTRACE_GETSIGINFO, event_child->lwpid, 0, &info) == 0)
763
            info_p = &info;
764
          else
765
            info_p = NULL;
766
          linux_resume_one_process (&event_child->head,
767
                                    event_child->stepping,
768
                                    WSTOPSIG (wstat), info_p);
769
          continue;
770
        }
771
 
772
      /* If this event was not handled above, and is not a SIGTRAP, report
773
         it.  */
774
      if (!WIFSTOPPED (wstat) || WSTOPSIG (wstat) != SIGTRAP)
775
        return wstat;
776
 
777
      /* If this target does not support breakpoints, we simply report the
778
         SIGTRAP; it's of no concern to us.  */
779
      if (the_low_target.get_pc == NULL)
780
        return wstat;
781
 
782
      stop_pc = get_stop_pc ();
783
 
784
      /* bp_reinsert will only be set if we were single-stepping.
785
         Notice that we will resume the process after hitting
786
         a gdbserver breakpoint; single-stepping to/over one
787
         is not supported (yet).  */
788
      if (event_child->bp_reinsert != 0)
789
        {
790
          if (debug_threads)
791
            fprintf (stderr, "Reinserted breakpoint.\n");
792
          reinsert_breakpoint (event_child->bp_reinsert);
793
          event_child->bp_reinsert = 0;
794
 
795
          /* Clear the single-stepping flag and SIGTRAP as we resume.  */
796
          linux_resume_one_process (&event_child->head, 0, 0, NULL);
797
          continue;
798
        }
799
 
800
      bp_status = check_breakpoints (stop_pc);
801
 
802
      if (bp_status != 0)
803
        {
804
          if (debug_threads)
805
            fprintf (stderr, "Hit a gdbserver breakpoint.\n");
806
 
807
          /* We hit one of our own breakpoints.  We mark it as a pending
808
             breakpoint, so that check_removed_breakpoint () will do the PC
809
             adjustment for us at the appropriate time.  */
810
          event_child->pending_is_breakpoint = 1;
811
          event_child->pending_stop_pc = stop_pc;
812
 
813
          /* We may need to put the breakpoint back.  We continue in the event
814
             loop instead of simply replacing the breakpoint right away,
815
             in order to not lose signals sent to the thread that hit the
816
             breakpoint.  Unfortunately this increases the window where another
817
             thread could sneak past the removed breakpoint.  For the current
818
             use of server-side breakpoints (thread creation) this is
819
             acceptable; but it needs to be considered before this breakpoint
820
             mechanism can be used in more general ways.  For some breakpoints
821
             it may be necessary to stop all other threads, but that should
822
             be avoided where possible.
823
 
824
             If breakpoint_reinsert_addr is NULL, that means that we can
825
             use PTRACE_SINGLESTEP on this platform.  Uninsert the breakpoint,
826
             mark it for reinsertion, and single-step.
827
 
828
             Otherwise, call the target function to figure out where we need
829
             our temporary breakpoint, create it, and continue executing this
830
             process.  */
831
          if (bp_status == 2)
832
            /* No need to reinsert.  */
833
            linux_resume_one_process (&event_child->head, 0, 0, NULL);
834
          else if (the_low_target.breakpoint_reinsert_addr == NULL)
835
            {
836
              event_child->bp_reinsert = stop_pc;
837
              uninsert_breakpoint (stop_pc);
838
              linux_resume_one_process (&event_child->head, 1, 0, NULL);
839
            }
840
          else
841
            {
842
              reinsert_breakpoint_by_bp
843
                (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ());
844
              linux_resume_one_process (&event_child->head, 0, 0, NULL);
845
            }
846
 
847
          continue;
848
        }
849
 
850
      if (debug_threads)
851
        fprintf (stderr, "Hit a non-gdbserver breakpoint.\n");
852
 
853
      /* If we were single-stepping, we definitely want to report the
854
         SIGTRAP.  The single-step operation has completed, so also
855
         clear the stepping flag; in general this does not matter,
856
         because the SIGTRAP will be reported to the client, which
857
         will give us a new action for this thread, but clear it for
858
         consistency anyway.  It's safe to clear the stepping flag
859
         because the only consumer of get_stop_pc () after this point
860
         is check_removed_breakpoint, and pending_is_breakpoint is not
861
         set.  It might be wiser to use a step_completed flag instead.  */
862
      if (event_child->stepping)
863
        {
864
          event_child->stepping = 0;
865
          return wstat;
866
        }
867
 
868
      /* A SIGTRAP that we can't explain.  It may have been a breakpoint.
869
         Check if it is a breakpoint, and if so mark the process information
870
         accordingly.  This will handle both the necessary fiddling with the
871
         PC on decr_pc_after_break targets and suppressing extra threads
872
         hitting a breakpoint if two hit it at once and then GDB removes it
873
         after the first is reported.  Arguably it would be better to report
874
         multiple threads hitting breakpoints simultaneously, but the current
875
         remote protocol does not allow this.  */
876
      if ((*the_low_target.breakpoint_at) (stop_pc))
877
        {
878
          event_child->pending_is_breakpoint = 1;
879
          event_child->pending_stop_pc = stop_pc;
880
        }
881
 
882
      return wstat;
883
    }
884
 
885
  /* NOTREACHED */
886
  return 0;
887
}
888
 
889
/* Wait for process, returns status.  */
890
 
891
static unsigned char
892
linux_wait (char *status)
893
{
894
  int w;
895
  struct thread_info *child = NULL;
896
 
897
retry:
898
  /* If we were only supposed to resume one thread, only wait for
899
     that thread - if it's still alive.  If it died, however - which
900
     can happen if we're coming from the thread death case below -
901
     then we need to make sure we restart the other threads.  We could
902
     pick a thread at random or restart all; restarting all is less
903
     arbitrary.  */
904
  if (cont_thread != 0 && cont_thread != -1)
905
    {
906
      child = (struct thread_info *) find_inferior_id (&all_threads,
907
                                                       cont_thread);
908
 
909
      /* No stepping, no signal - unless one is pending already, of course.  */
910
      if (child == NULL)
911
        {
912
          struct thread_resume resume_info;
913
          resume_info.thread = -1;
914
          resume_info.step = resume_info.sig = resume_info.leave_stopped = 0;
915
          linux_resume (&resume_info);
916
        }
917
    }
918
 
919
  w = linux_wait_for_event (child);
920
  stop_all_processes ();
921
 
922
  if (must_set_ptrace_flags)
923
    {
924
      ptrace (PTRACE_SETOPTIONS, inferior_pid, 0, PTRACE_O_TRACECLONE);
925
      must_set_ptrace_flags = 0;
926
    }
927
 
928
  /* If we are waiting for a particular child, and it exited,
929
     linux_wait_for_event will return its exit status.  Similarly if
930
     the last child exited.  If this is not the last child, however,
931
     do not report it as exited until there is a 'thread exited' response
932
     available in the remote protocol.  Instead, just wait for another event.
933
     This should be safe, because if the thread crashed we will already
934
     have reported the termination signal to GDB; that should stop any
935
     in-progress stepping operations, etc.
936
 
937
     Report the exit status of the last thread to exit.  This matches
938
     LinuxThreads' behavior.  */
939
 
940
  if (all_threads.head == all_threads.tail)
941
    {
942
      if (WIFEXITED (w))
943
        {
944
          fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
945
          *status = 'W';
946
          clear_inferiors ();
947
          free (all_processes.head);
948
          all_processes.head = all_processes.tail = NULL;
949
          return WEXITSTATUS (w);
950
        }
951
      else if (!WIFSTOPPED (w))
952
        {
953
          fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
954
          *status = 'X';
955
          clear_inferiors ();
956
          free (all_processes.head);
957
          all_processes.head = all_processes.tail = NULL;
958
          return target_signal_from_host (WTERMSIG (w));
959
        }
960
    }
961
  else
962
    {
963
      if (!WIFSTOPPED (w))
964
        goto retry;
965
    }
966
 
967
  *status = 'T';
968
  return target_signal_from_host (WSTOPSIG (w));
969
}
970
 
971
/* Send a signal to an LWP.  For LinuxThreads, kill is enough; however, if
972
   thread groups are in use, we need to use tkill.  */
973
 
974
static int
975
kill_lwp (unsigned long lwpid, int signo)
976
{
977
  static int tkill_failed;
978
 
979
  errno = 0;
980
 
981
#ifdef SYS_tkill
982
  if (!tkill_failed)
983
    {
984
      int ret = syscall (SYS_tkill, lwpid, signo);
985
      if (errno != ENOSYS)
986
        return ret;
987
      errno = 0;
988
      tkill_failed = 1;
989
    }
990
#endif
991
 
992
  return kill (lwpid, signo);
993
}
994
 
995
static void
996
send_sigstop (struct inferior_list_entry *entry)
997
{
998
  struct process_info *process = (struct process_info *) entry;
999
 
1000
  if (process->stopped)
1001
    return;
1002
 
1003
  /* If we already have a pending stop signal for this process, don't
1004
     send another.  */
1005
  if (process->stop_expected)
1006
    {
1007
      if (debug_threads)
1008
        fprintf (stderr, "Have pending sigstop for process %ld\n",
1009
                 process->lwpid);
1010
 
1011
      /* We clear the stop_expected flag so that wait_for_sigstop
1012
         will receive the SIGSTOP event (instead of silently resuming and
1013
         waiting again).  It'll be reset below.  */
1014
      process->stop_expected = 0;
1015
      return;
1016
    }
1017
 
1018
  if (debug_threads)
1019
    fprintf (stderr, "Sending sigstop to process %ld\n", process->head.id);
1020
 
1021
  kill_lwp (process->head.id, SIGSTOP);
1022
}
1023
 
1024
static void
1025
wait_for_sigstop (struct inferior_list_entry *entry)
1026
{
1027
  struct process_info *process = (struct process_info *) entry;
1028
  struct thread_info *saved_inferior, *thread;
1029
  int wstat;
1030
  unsigned long saved_tid;
1031
 
1032
  if (process->stopped)
1033
    return;
1034
 
1035
  saved_inferior = current_inferior;
1036
  saved_tid = ((struct inferior_list_entry *) saved_inferior)->id;
1037
  thread = (struct thread_info *) find_inferior_id (&all_threads,
1038
                                                    process->lwpid);
1039
  wstat = linux_wait_for_event (thread);
1040
 
1041
  /* If we stopped with a non-SIGSTOP signal, save it for later
1042
     and record the pending SIGSTOP.  If the process exited, just
1043
     return.  */
1044
  if (WIFSTOPPED (wstat)
1045
      && WSTOPSIG (wstat) != SIGSTOP)
1046
    {
1047
      if (debug_threads)
1048
        fprintf (stderr, "LWP %ld stopped with non-sigstop status %06x\n",
1049
                 process->lwpid, wstat);
1050
      process->status_pending_p = 1;
1051
      process->status_pending = wstat;
1052
      process->stop_expected = 1;
1053
    }
1054
 
1055
  if (linux_thread_alive (saved_tid))
1056
    current_inferior = saved_inferior;
1057
  else
1058
    {
1059
      if (debug_threads)
1060
        fprintf (stderr, "Previously current thread died.\n");
1061
 
1062
      /* Set a valid thread as current.  */
1063
      set_desired_inferior (0);
1064
    }
1065
}
1066
 
1067
static void
1068
stop_all_processes (void)
1069
{
1070
  stopping_threads = 1;
1071
  for_each_inferior (&all_processes, send_sigstop);
1072
  for_each_inferior (&all_processes, wait_for_sigstop);
1073
  stopping_threads = 0;
1074
}
1075
 
1076
/* Resume execution of the inferior process.
1077
   If STEP is nonzero, single-step it.
1078
   If SIGNAL is nonzero, give it that signal.  */
1079
 
1080
static void
1081
linux_resume_one_process (struct inferior_list_entry *entry,
1082
                          int step, int signal, siginfo_t *info)
1083
{
1084
  struct process_info *process = (struct process_info *) entry;
1085
  struct thread_info *saved_inferior;
1086
 
1087
  if (process->stopped == 0)
1088
    return;
1089
 
1090
  /* If we have pending signals or status, and a new signal, enqueue the
1091
     signal.  Also enqueue the signal if we are waiting to reinsert a
1092
     breakpoint; it will be picked up again below.  */
1093
  if (signal != 0
1094
      && (process->status_pending_p || process->pending_signals != NULL
1095
          || process->bp_reinsert != 0))
1096
    {
1097
      struct pending_signals *p_sig;
1098
      p_sig = malloc (sizeof (*p_sig));
1099
      p_sig->prev = process->pending_signals;
1100
      p_sig->signal = signal;
1101
      if (info == NULL)
1102
        memset (&p_sig->info, 0, sizeof (siginfo_t));
1103
      else
1104
        memcpy (&p_sig->info, info, sizeof (siginfo_t));
1105
      process->pending_signals = p_sig;
1106
    }
1107
 
1108
  if (process->status_pending_p && !check_removed_breakpoint (process))
1109
    return;
1110
 
1111
  saved_inferior = current_inferior;
1112
  current_inferior = get_process_thread (process);
1113
 
1114
  if (debug_threads)
1115
    fprintf (stderr, "Resuming process %ld (%s, signal %d, stop %s)\n", inferior_pid,
1116
             step ? "step" : "continue", signal,
1117
             process->stop_expected ? "expected" : "not expected");
1118
 
1119
  /* This bit needs some thinking about.  If we get a signal that
1120
     we must report while a single-step reinsert is still pending,
1121
     we often end up resuming the thread.  It might be better to
1122
     (ew) allow a stack of pending events; then we could be sure that
1123
     the reinsert happened right away and not lose any signals.
1124
 
1125
     Making this stack would also shrink the window in which breakpoints are
1126
     uninserted (see comment in linux_wait_for_process) but not enough for
1127
     complete correctness, so it won't solve that problem.  It may be
1128
     worthwhile just to solve this one, however.  */
1129
  if (process->bp_reinsert != 0)
1130
    {
1131
      if (debug_threads)
1132
        fprintf (stderr, "  pending reinsert at %08lx", (long)process->bp_reinsert);
1133
      if (step == 0)
1134
        fprintf (stderr, "BAD - reinserting but not stepping.\n");
1135
      step = 1;
1136
 
1137
      /* Postpone any pending signal.  It was enqueued above.  */
1138
      signal = 0;
1139
    }
1140
 
1141
  check_removed_breakpoint (process);
1142
 
1143
  if (debug_threads && the_low_target.get_pc != NULL)
1144
    {
1145
      fprintf (stderr, "  ");
1146
      (*the_low_target.get_pc) ();
1147
    }
1148
 
1149
  /* If we have pending signals, consume one unless we are trying to reinsert
1150
     a breakpoint.  */
1151
  if (process->pending_signals != NULL && process->bp_reinsert == 0)
1152
    {
1153
      struct pending_signals **p_sig;
1154
 
1155
      p_sig = &process->pending_signals;
1156
      while ((*p_sig)->prev != NULL)
1157
        p_sig = &(*p_sig)->prev;
1158
 
1159
      signal = (*p_sig)->signal;
1160
      if ((*p_sig)->info.si_signo != 0)
1161
        ptrace (PTRACE_SETSIGINFO, process->lwpid, 0, &(*p_sig)->info);
1162
 
1163
      free (*p_sig);
1164
      *p_sig = NULL;
1165
    }
1166
 
1167
  regcache_invalidate_one ((struct inferior_list_entry *)
1168
                           get_process_thread (process));
1169
  errno = 0;
1170
  process->stopped = 0;
1171
  process->stepping = step;
1172
  ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, process->lwpid, 0, signal);
1173
 
1174
  current_inferior = saved_inferior;
1175
  if (errno)
1176
    perror_with_name ("ptrace");
1177
}
1178
 
1179
static struct thread_resume *resume_ptr;
1180
 
1181
/* This function is called once per thread.  We look up the thread
1182
   in RESUME_PTR, and mark the thread with a pointer to the appropriate
1183
   resume request.
1184
 
1185
   This algorithm is O(threads * resume elements), but resume elements
1186
   is small (and will remain small at least until GDB supports thread
1187
   suspension).  */
1188
static void
1189
linux_set_resume_request (struct inferior_list_entry *entry)
1190
{
1191
  struct process_info *process;
1192
  struct thread_info *thread;
1193
  int ndx;
1194
 
1195
  thread = (struct thread_info *) entry;
1196
  process = get_thread_process (thread);
1197
 
1198
  ndx = 0;
1199
  while (resume_ptr[ndx].thread != -1 && resume_ptr[ndx].thread != entry->id)
1200
    ndx++;
1201
 
1202
  process->resume = &resume_ptr[ndx];
1203
}
1204
 
1205
/* This function is called once per thread.  We check the thread's resume
1206
   request, which will tell us whether to resume, step, or leave the thread
1207
   stopped; and what signal, if any, it should be sent.  For threads which
1208
   we aren't explicitly told otherwise, we preserve the stepping flag; this
1209
   is used for stepping over gdbserver-placed breakpoints.  */
1210
 
1211
static void
1212
linux_continue_one_thread (struct inferior_list_entry *entry)
1213
{
1214
  struct process_info *process;
1215
  struct thread_info *thread;
1216
  int step;
1217
 
1218
  thread = (struct thread_info *) entry;
1219
  process = get_thread_process (thread);
1220
 
1221
  if (process->resume->leave_stopped)
1222
    return;
1223
 
1224
  if (process->resume->thread == -1)
1225
    step = process->stepping || process->resume->step;
1226
  else
1227
    step = process->resume->step;
1228
 
1229
  linux_resume_one_process (&process->head, step, process->resume->sig, NULL);
1230
 
1231
  process->resume = NULL;
1232
}
1233
 
1234
/* This function is called once per thread.  We check the thread's resume
1235
   request, which will tell us whether to resume, step, or leave the thread
1236
   stopped; and what signal, if any, it should be sent.  We queue any needed
1237
   signals, since we won't actually resume.  We already have a pending event
1238
   to report, so we don't need to preserve any step requests; they should
1239
   be re-issued if necessary.  */
1240
 
1241
static void
1242
linux_queue_one_thread (struct inferior_list_entry *entry)
1243
{
1244
  struct process_info *process;
1245
  struct thread_info *thread;
1246
 
1247
  thread = (struct thread_info *) entry;
1248
  process = get_thread_process (thread);
1249
 
1250
  if (process->resume->leave_stopped)
1251
    return;
1252
 
1253
  /* If we have a new signal, enqueue the signal.  */
1254
  if (process->resume->sig != 0)
1255
    {
1256
      struct pending_signals *p_sig;
1257
      p_sig = malloc (sizeof (*p_sig));
1258
      p_sig->prev = process->pending_signals;
1259
      p_sig->signal = process->resume->sig;
1260
      memset (&p_sig->info, 0, sizeof (siginfo_t));
1261
 
1262
      /* If this is the same signal we were previously stopped by,
1263
         make sure to queue its siginfo.  We can ignore the return
1264
         value of ptrace; if it fails, we'll skip
1265
         PTRACE_SETSIGINFO.  */
1266
      if (WIFSTOPPED (process->last_status)
1267
          && WSTOPSIG (process->last_status) == process->resume->sig)
1268
        ptrace (PTRACE_GETSIGINFO, process->lwpid, 0, &p_sig->info);
1269
 
1270
      process->pending_signals = p_sig;
1271
    }
1272
 
1273
  process->resume = NULL;
1274
}
1275
 
1276
/* Set DUMMY if this process has an interesting status pending.  */
1277
static int
1278
resume_status_pending_p (struct inferior_list_entry *entry, void *flag_p)
1279
{
1280
  struct process_info *process = (struct process_info *) entry;
1281
 
1282
  /* Processes which will not be resumed are not interesting, because
1283
     we might not wait for them next time through linux_wait.  */
1284
  if (process->resume->leave_stopped)
1285
    return 0;
1286
 
1287
  /* If this thread has a removed breakpoint, we won't have any
1288
     events to report later, so check now.  check_removed_breakpoint
1289
     may clear status_pending_p.  We avoid calling check_removed_breakpoint
1290
     for any thread that we are not otherwise going to resume - this
1291
     lets us preserve stopped status when two threads hit a breakpoint.
1292
     GDB removes the breakpoint to single-step a particular thread
1293
     past it, then re-inserts it and resumes all threads.  We want
1294
     to report the second thread without resuming it in the interim.  */
1295
  if (process->status_pending_p)
1296
    check_removed_breakpoint (process);
1297
 
1298
  if (process->status_pending_p)
1299
    * (int *) flag_p = 1;
1300
 
1301
  return 0;
1302
}
1303
 
1304
static void
1305
linux_resume (struct thread_resume *resume_info)
1306
{
1307
  int pending_flag;
1308
 
1309
  /* Yes, the use of a global here is rather ugly.  */
1310
  resume_ptr = resume_info;
1311
 
1312
  for_each_inferior (&all_threads, linux_set_resume_request);
1313
 
1314
  /* If there is a thread which would otherwise be resumed, which
1315
     has a pending status, then don't resume any threads - we can just
1316
     report the pending status.  Make sure to queue any signals
1317
     that would otherwise be sent.  */
1318
  pending_flag = 0;
1319
  find_inferior (&all_processes, resume_status_pending_p, &pending_flag);
1320
 
1321
  if (debug_threads)
1322
    {
1323
      if (pending_flag)
1324
        fprintf (stderr, "Not resuming, pending status\n");
1325
      else
1326
        fprintf (stderr, "Resuming, no pending status\n");
1327
    }
1328
 
1329
  if (pending_flag)
1330
    for_each_inferior (&all_threads, linux_queue_one_thread);
1331
  else
1332
    for_each_inferior (&all_threads, linux_continue_one_thread);
1333
}
1334
 
1335
#ifdef HAVE_LINUX_USRREGS
1336
 
1337
int
1338
register_addr (int regnum)
1339
{
1340
  int addr;
1341
 
1342
  if (regnum < 0 || regnum >= the_low_target.num_regs)
1343
    error ("Invalid register number %d.", regnum);
1344
 
1345
  addr = the_low_target.regmap[regnum];
1346
 
1347
  return addr;
1348
}
1349
 
1350
/* Fetch one register.  */
1351
static void
1352
fetch_register (int regno)
1353
{
1354
  CORE_ADDR regaddr;
1355
  int i, size;
1356
  char *buf;
1357
 
1358
  if (regno >= the_low_target.num_regs)
1359
    return;
1360
  if ((*the_low_target.cannot_fetch_register) (regno))
1361
    return;
1362
 
1363
  regaddr = register_addr (regno);
1364
  if (regaddr == -1)
1365
    return;
1366
  size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1)
1367
         & - sizeof (PTRACE_XFER_TYPE);
1368
  buf = alloca (size);
1369
  for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE))
1370
    {
1371
      errno = 0;
1372
      *(PTRACE_XFER_TYPE *) (buf + i) =
1373
        ptrace (PTRACE_PEEKUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, 0);
1374
      regaddr += sizeof (PTRACE_XFER_TYPE);
1375
      if (errno != 0)
1376
        {
1377
          /* Warning, not error, in case we are attached; sometimes the
1378
             kernel doesn't let us at the registers.  */
1379
          char *err = strerror (errno);
1380
          char *msg = alloca (strlen (err) + 128);
1381
          sprintf (msg, "reading register %d: %s", regno, err);
1382
          error (msg);
1383
          goto error_exit;
1384
        }
1385
    }
1386
  if (the_low_target.left_pad_xfer
1387
      && register_size (regno) < sizeof (PTRACE_XFER_TYPE))
1388
    supply_register (regno, (buf + sizeof (PTRACE_XFER_TYPE)
1389
                             - register_size (regno)));
1390
  else
1391
    supply_register (regno, buf);
1392
 
1393
error_exit:;
1394
}
1395
 
1396
/* Fetch all registers, or just one, from the child process.  */
1397
static void
1398
usr_fetch_inferior_registers (int regno)
1399
{
1400
  if (regno == -1 || regno == 0)
1401
    for (regno = 0; regno < the_low_target.num_regs; regno++)
1402
      fetch_register (regno);
1403
  else
1404
    fetch_register (regno);
1405
}
1406
 
1407
/* Store our register values back into the inferior.
1408
   If REGNO is -1, do this for all registers.
1409
   Otherwise, REGNO specifies which register (so we can save time).  */
1410
static void
1411
usr_store_inferior_registers (int regno)
1412
{
1413
  CORE_ADDR regaddr;
1414
  int i, size;
1415
  char *buf;
1416
 
1417
  if (regno >= 0)
1418
    {
1419
      if (regno >= the_low_target.num_regs)
1420
        return;
1421
 
1422
      if ((*the_low_target.cannot_store_register) (regno) == 1)
1423
        return;
1424
 
1425
      regaddr = register_addr (regno);
1426
      if (regaddr == -1)
1427
        return;
1428
      errno = 0;
1429
      size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1)
1430
             & - sizeof (PTRACE_XFER_TYPE);
1431
      buf = alloca (size);
1432
      memset (buf, 0, size);
1433
      if (the_low_target.left_pad_xfer
1434
          && register_size (regno) < sizeof (PTRACE_XFER_TYPE))
1435
        collect_register (regno, (buf + sizeof (PTRACE_XFER_TYPE)
1436
                                  - register_size (regno)));
1437
      else
1438
        collect_register (regno, buf);
1439
      for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE))
1440
        {
1441
          errno = 0;
1442
          ptrace (PTRACE_POKEUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
1443
                  *(PTRACE_XFER_TYPE *) (buf + i));
1444
          if (errno != 0)
1445
            {
1446
              if ((*the_low_target.cannot_store_register) (regno) == 0)
1447
                {
1448
                  char *err = strerror (errno);
1449
                  char *msg = alloca (strlen (err) + 128);
1450
                  sprintf (msg, "writing register %d: %s",
1451
                           regno, err);
1452
                  error (msg);
1453
                  return;
1454
                }
1455
            }
1456
          regaddr += sizeof (PTRACE_XFER_TYPE);
1457
        }
1458
    }
1459
  else
1460
    for (regno = 0; regno < the_low_target.num_regs; regno++)
1461
      usr_store_inferior_registers (regno);
1462
}
1463
#endif /* HAVE_LINUX_USRREGS */
1464
 
1465
 
1466
 
1467
#ifdef HAVE_LINUX_REGSETS
1468
 
1469
static int
1470
regsets_fetch_inferior_registers ()
1471
{
1472
  struct regset_info *regset;
1473
  int saw_general_regs = 0;
1474
 
1475
  regset = target_regsets;
1476
 
1477
  while (regset->size >= 0)
1478
    {
1479
      void *buf;
1480
      int res;
1481
 
1482
      if (regset->size == 0)
1483
        {
1484
          regset ++;
1485
          continue;
1486
        }
1487
 
1488
      buf = malloc (regset->size);
1489
      res = ptrace (regset->get_request, inferior_pid, 0, buf);
1490
      if (res < 0)
1491
        {
1492
          if (errno == EIO)
1493
            {
1494
              /* If we get EIO on the first regset, do not try regsets again.
1495
                 If we get EIO on a later regset, disable that regset.  */
1496
              if (regset == target_regsets)
1497
                {
1498
                  use_regsets_p = 0;
1499
                  return -1;
1500
                }
1501
              else
1502
                {
1503
                  regset->size = 0;
1504
                  continue;
1505
                }
1506
            }
1507
          else
1508
            {
1509
              char s[256];
1510
              sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%ld",
1511
                       inferior_pid);
1512
              perror (s);
1513
            }
1514
        }
1515
      else if (regset->type == GENERAL_REGS)
1516
        saw_general_regs = 1;
1517
      regset->store_function (buf);
1518
      regset ++;
1519
    }
1520
  if (saw_general_regs)
1521
    return 0;
1522
  else
1523
    return 1;
1524
}
1525
 
1526
static int
1527
regsets_store_inferior_registers ()
1528
{
1529
  struct regset_info *regset;
1530
  int saw_general_regs = 0;
1531
 
1532
  regset = target_regsets;
1533
 
1534
  while (regset->size >= 0)
1535
    {
1536
      void *buf;
1537
      int res;
1538
 
1539
      if (regset->size == 0)
1540
        {
1541
          regset ++;
1542
          continue;
1543
        }
1544
 
1545
      buf = malloc (regset->size);
1546
 
1547
      /* First fill the buffer with the current register set contents,
1548
         in case there are any items in the kernel's regset that are
1549
         not in gdbserver's regcache.  */
1550
      res = ptrace (regset->get_request, inferior_pid, 0, buf);
1551
 
1552
      if (res == 0)
1553
        {
1554
          /* Then overlay our cached registers on that.  */
1555
          regset->fill_function (buf);
1556
 
1557
          /* Only now do we write the register set.  */
1558
          res = ptrace (regset->set_request, inferior_pid, 0, buf);
1559
        }
1560
 
1561
      if (res < 0)
1562
        {
1563
          if (errno == EIO)
1564
            {
1565
              /* If we get EIO on the first regset, do not try regsets again.
1566
                 If we get EIO on a later regset, disable that regset.  */
1567
              if (regset == target_regsets)
1568
                {
1569
                  use_regsets_p = 0;
1570
                  return -1;
1571
                }
1572
              else
1573
                {
1574
                  regset->size = 0;
1575
                  continue;
1576
                }
1577
            }
1578
          else
1579
            {
1580
              perror ("Warning: ptrace(regsets_store_inferior_registers)");
1581
            }
1582
        }
1583
      else if (regset->type == GENERAL_REGS)
1584
        saw_general_regs = 1;
1585
      regset ++;
1586
      free (buf);
1587
    }
1588
  if (saw_general_regs)
1589
    return 0;
1590
  else
1591
    return 1;
1592
  return 0;
1593
}
1594
 
1595
#endif /* HAVE_LINUX_REGSETS */
1596
 
1597
 
1598
void
1599
linux_fetch_registers (int regno)
1600
{
1601
#ifdef HAVE_LINUX_REGSETS
1602
  if (use_regsets_p)
1603
    {
1604
      if (regsets_fetch_inferior_registers () == 0)
1605
        return;
1606
    }
1607
#endif
1608
#ifdef HAVE_LINUX_USRREGS
1609
  usr_fetch_inferior_registers (regno);
1610
#endif
1611
}
1612
 
1613
void
1614
linux_store_registers (int regno)
1615
{
1616
#ifdef HAVE_LINUX_REGSETS
1617
  if (use_regsets_p)
1618
    {
1619
      if (regsets_store_inferior_registers () == 0)
1620
        return;
1621
    }
1622
#endif
1623
#ifdef HAVE_LINUX_USRREGS
1624
  usr_store_inferior_registers (regno);
1625
#endif
1626
}
1627
 
1628
 
1629
/* Copy LEN bytes from inferior's memory starting at MEMADDR
1630
   to debugger memory starting at MYADDR.  */
1631
 
1632
static int
1633
linux_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
1634
{
1635
  register int i;
1636
  /* Round starting address down to longword boundary.  */
1637
  register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
1638
  /* Round ending address up; get number of longwords that makes.  */
1639
  register int count
1640
    = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
1641
      / sizeof (PTRACE_XFER_TYPE);
1642
  /* Allocate buffer of that many longwords.  */
1643
  register PTRACE_XFER_TYPE *buffer
1644
    = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
1645
  int fd;
1646
  char filename[64];
1647
 
1648
  /* Try using /proc.  Don't bother for one word.  */
1649
  if (len >= 3 * sizeof (long))
1650
    {
1651
      /* We could keep this file open and cache it - possibly one per
1652
         thread.  That requires some juggling, but is even faster.  */
1653
      sprintf (filename, "/proc/%ld/mem", inferior_pid);
1654
      fd = open (filename, O_RDONLY | O_LARGEFILE);
1655
      if (fd == -1)
1656
        goto no_proc;
1657
 
1658
      /* If pread64 is available, use it.  It's faster if the kernel
1659
         supports it (only one syscall), and it's 64-bit safe even on
1660
         32-bit platforms (for instance, SPARC debugging a SPARC64
1661
         application).  */
1662
#ifdef HAVE_PREAD64
1663
      if (pread64 (fd, myaddr, len, memaddr) != len)
1664
#else
1665
      if (lseek (fd, memaddr, SEEK_SET) == -1 || read (fd, memaddr, len) != len)
1666
#endif
1667
        {
1668
          close (fd);
1669
          goto no_proc;
1670
        }
1671
 
1672
      close (fd);
1673
      return 0;
1674
    }
1675
 
1676
 no_proc:
1677
  /* Read all the longwords */
1678
  for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
1679
    {
1680
      errno = 0;
1681
      buffer[i] = ptrace (PTRACE_PEEKTEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, 0);
1682
      if (errno)
1683
        return errno;
1684
    }
1685
 
1686
  /* Copy appropriate bytes out of the buffer.  */
1687
  memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), len);
1688
 
1689
  return 0;
1690
}
1691
 
1692
/* Copy LEN bytes of data from debugger memory at MYADDR
1693
   to inferior's memory at MEMADDR.
1694
   On failure (cannot write the inferior)
1695
   returns the value of errno.  */
1696
 
1697
static int
1698
linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
1699
{
1700
  register int i;
1701
  /* Round starting address down to longword boundary.  */
1702
  register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
1703
  /* Round ending address up; get number of longwords that makes.  */
1704
  register int count
1705
  = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE);
1706
  /* Allocate buffer of that many longwords.  */
1707
  register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
1708
  extern int errno;
1709
 
1710
  if (debug_threads)
1711
    {
1712
      fprintf (stderr, "Writing %02x to %08lx\n", (unsigned)myaddr[0], (long)memaddr);
1713
    }
1714
 
1715
  /* Fill start and end extra bytes of buffer with existing memory data.  */
1716
 
1717
  buffer[0] = ptrace (PTRACE_PEEKTEXT, inferior_pid,
1718
                      (PTRACE_ARG3_TYPE) addr, 0);
1719
 
1720
  if (count > 1)
1721
    {
1722
      buffer[count - 1]
1723
        = ptrace (PTRACE_PEEKTEXT, inferior_pid,
1724
                  (PTRACE_ARG3_TYPE) (addr + (count - 1)
1725
                                      * sizeof (PTRACE_XFER_TYPE)),
1726
                  0);
1727
    }
1728
 
1729
  /* Copy data to be written over corresponding part of buffer */
1730
 
1731
  memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), myaddr, len);
1732
 
1733
  /* Write the entire buffer.  */
1734
 
1735
  for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
1736
    {
1737
      errno = 0;
1738
      ptrace (PTRACE_POKETEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, buffer[i]);
1739
      if (errno)
1740
        return errno;
1741
    }
1742
 
1743
  return 0;
1744
}
1745
 
1746
static int linux_supports_tracefork_flag;
1747
 
1748
/* Helper functions for linux_test_for_tracefork, called via clone ().  */
1749
 
1750
static int
1751
linux_tracefork_grandchild (void *arg)
1752
{
1753
  _exit (0);
1754
}
1755
 
1756
#define STACK_SIZE 4096
1757
 
1758
static int
1759
linux_tracefork_child (void *arg)
1760
{
1761
  ptrace (PTRACE_TRACEME, 0, 0, 0);
1762
  kill (getpid (), SIGSTOP);
1763
#ifdef __ia64__
1764
  __clone2 (linux_tracefork_grandchild, arg, STACK_SIZE,
1765
            CLONE_VM | SIGCHLD, NULL);
1766
#else
1767
  clone (linux_tracefork_grandchild, arg + STACK_SIZE,
1768
         CLONE_VM | SIGCHLD, NULL);
1769
#endif
1770
  _exit (0);
1771
}
1772
 
1773
/* Wrapper function for waitpid which handles EINTR.  */
1774
 
1775
static int
1776
my_waitpid (int pid, int *status, int flags)
1777
{
1778
  int ret;
1779
  do
1780
    {
1781
      ret = waitpid (pid, status, flags);
1782
    }
1783
  while (ret == -1 && errno == EINTR);
1784
 
1785
  return ret;
1786
}
1787
 
1788
/* Determine if PTRACE_O_TRACEFORK can be used to follow fork events.  Make
1789
   sure that we can enable the option, and that it had the desired
1790
   effect.  */
1791
 
1792
static void
1793
linux_test_for_tracefork (void)
1794
{
1795
  int child_pid, ret, status;
1796
  long second_pid;
1797
  char *stack = malloc (STACK_SIZE * 4);
1798
 
1799
  linux_supports_tracefork_flag = 0;
1800
 
1801
  /* Use CLONE_VM instead of fork, to support uClinux (no MMU).  */
1802
#ifdef __ia64__
1803
  child_pid = __clone2 (linux_tracefork_child, stack, STACK_SIZE,
1804
                        CLONE_VM | SIGCHLD, stack + STACK_SIZE * 2);
1805
#else
1806
  child_pid = clone (linux_tracefork_child, stack + STACK_SIZE,
1807
                     CLONE_VM | SIGCHLD, stack + STACK_SIZE * 2);
1808
#endif
1809
  if (child_pid == -1)
1810
    perror_with_name ("clone");
1811
 
1812
  ret = my_waitpid (child_pid, &status, 0);
1813
  if (ret == -1)
1814
    perror_with_name ("waitpid");
1815
  else if (ret != child_pid)
1816
    error ("linux_test_for_tracefork: waitpid: unexpected result %d.", ret);
1817
  if (! WIFSTOPPED (status))
1818
    error ("linux_test_for_tracefork: waitpid: unexpected status %d.", status);
1819
 
1820
  ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK);
1821
  if (ret != 0)
1822
    {
1823
      ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
1824
      if (ret != 0)
1825
        {
1826
          warning ("linux_test_for_tracefork: failed to kill child");
1827
          return;
1828
        }
1829
 
1830
      ret = my_waitpid (child_pid, &status, 0);
1831
      if (ret != child_pid)
1832
        warning ("linux_test_for_tracefork: failed to wait for killed child");
1833
      else if (!WIFSIGNALED (status))
1834
        warning ("linux_test_for_tracefork: unexpected wait status 0x%x from "
1835
                 "killed child", status);
1836
 
1837
      return;
1838
    }
1839
 
1840
  ret = ptrace (PTRACE_CONT, child_pid, 0, 0);
1841
  if (ret != 0)
1842
    warning ("linux_test_for_tracefork: failed to resume child");
1843
 
1844
  ret = my_waitpid (child_pid, &status, 0);
1845
 
1846
  if (ret == child_pid && WIFSTOPPED (status)
1847
      && status >> 16 == PTRACE_EVENT_FORK)
1848
    {
1849
      second_pid = 0;
1850
      ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid);
1851
      if (ret == 0 && second_pid != 0)
1852
        {
1853
          int second_status;
1854
 
1855
          linux_supports_tracefork_flag = 1;
1856
          my_waitpid (second_pid, &second_status, 0);
1857
          ret = ptrace (PTRACE_KILL, second_pid, 0, 0);
1858
          if (ret != 0)
1859
            warning ("linux_test_for_tracefork: failed to kill second child");
1860
          my_waitpid (second_pid, &status, 0);
1861
        }
1862
    }
1863
  else
1864
    warning ("linux_test_for_tracefork: unexpected result from waitpid "
1865
             "(%d, status 0x%x)", ret, status);
1866
 
1867
  do
1868
    {
1869
      ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
1870
      if (ret != 0)
1871
        warning ("linux_test_for_tracefork: failed to kill child");
1872
      my_waitpid (child_pid, &status, 0);
1873
    }
1874
  while (WIFSTOPPED (status));
1875
 
1876
  free (stack);
1877
}
1878
 
1879
 
1880
static void
1881
linux_look_up_symbols (void)
1882
{
1883
#ifdef USE_THREAD_DB
1884
  if (thread_db_active)
1885
    return;
1886
 
1887
  thread_db_active = thread_db_init (!linux_supports_tracefork_flag);
1888
#endif
1889
}
1890
 
1891
static void
1892
linux_request_interrupt (void)
1893
{
1894
  extern unsigned long signal_pid;
1895
 
1896
  if (cont_thread != 0 && cont_thread != -1)
1897
    {
1898
      struct process_info *process;
1899
 
1900
      process = get_thread_process (current_inferior);
1901
      kill_lwp (process->lwpid, SIGINT);
1902
    }
1903
  else
1904
    kill_lwp (signal_pid, SIGINT);
1905
}
1906
 
1907
/* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET
1908
   to debugger memory starting at MYADDR.  */
1909
 
1910
static int
1911
linux_read_auxv (CORE_ADDR offset, unsigned char *myaddr, unsigned int len)
1912
{
1913
  char filename[PATH_MAX];
1914
  int fd, n;
1915
 
1916
  snprintf (filename, sizeof filename, "/proc/%ld/auxv", inferior_pid);
1917
 
1918
  fd = open (filename, O_RDONLY);
1919
  if (fd < 0)
1920
    return -1;
1921
 
1922
  if (offset != (CORE_ADDR) 0
1923
      && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
1924
    n = -1;
1925
  else
1926
    n = read (fd, myaddr, len);
1927
 
1928
  close (fd);
1929
 
1930
  return n;
1931
}
1932
 
1933
/* These watchpoint related wrapper functions simply pass on the function call
1934
   if the target has registered a corresponding function.  */
1935
 
1936
static int
1937
linux_insert_watchpoint (char type, CORE_ADDR addr, int len)
1938
{
1939
  if (the_low_target.insert_watchpoint != NULL)
1940
    return the_low_target.insert_watchpoint (type, addr, len);
1941
  else
1942
    /* Unsupported (see target.h).  */
1943
    return 1;
1944
}
1945
 
1946
static int
1947
linux_remove_watchpoint (char type, CORE_ADDR addr, int len)
1948
{
1949
  if (the_low_target.remove_watchpoint != NULL)
1950
    return the_low_target.remove_watchpoint (type, addr, len);
1951
  else
1952
    /* Unsupported (see target.h).  */
1953
    return 1;
1954
}
1955
 
1956
static int
1957
linux_stopped_by_watchpoint (void)
1958
{
1959
  if (the_low_target.stopped_by_watchpoint != NULL)
1960
    return the_low_target.stopped_by_watchpoint ();
1961
  else
1962
    return 0;
1963
}
1964
 
1965
static CORE_ADDR
1966
linux_stopped_data_address (void)
1967
{
1968
  if (the_low_target.stopped_data_address != NULL)
1969
    return the_low_target.stopped_data_address ();
1970
  else
1971
    return 0;
1972
}
1973
 
1974
#if defined(__UCLIBC__) && defined(HAS_NOMMU)
1975
#if defined(__mcoldfire__)
1976
/* These should really be defined in the kernel's ptrace.h header.  */
1977
#define PT_TEXT_ADDR 49*4
1978
#define PT_DATA_ADDR 50*4
1979
#define PT_TEXT_END_ADDR  51*4
1980
#endif
1981
 
1982
/* Under uClinux, programs are loaded at non-zero offsets, which we need
1983
   to tell gdb about.  */
1984
 
1985
static int
1986
linux_read_offsets (CORE_ADDR *text_p, CORE_ADDR *data_p)
1987
{
1988
#if defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) && defined(PT_TEXT_END_ADDR)
1989
  unsigned long text, text_end, data;
1990
  int pid = get_thread_process (current_inferior)->head.id;
1991
 
1992
  errno = 0;
1993
 
1994
  text = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_ADDR, 0);
1995
  text_end = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_END_ADDR, 0);
1996
  data = ptrace (PTRACE_PEEKUSER, pid, (long)PT_DATA_ADDR, 0);
1997
 
1998
  if (errno == 0)
1999
    {
2000
      /* Both text and data offsets produced at compile-time (and so
2001
         used by gdb) are relative to the beginning of the program,
2002
         with the data segment immediately following the text segment.
2003
         However, the actual runtime layout in memory may put the data
2004
         somewhere else, so when we send gdb a data base-address, we
2005
         use the real data base address and subtract the compile-time
2006
         data base-address from it (which is just the length of the
2007
         text segment).  BSS immediately follows data in both
2008
         cases.  */
2009
      *text_p = text;
2010
      *data_p = data - (text_end - text);
2011
 
2012
      return 1;
2013
    }
2014
#endif
2015
 return 0;
2016
}
2017
#endif
2018
 
2019
static const char *
2020
linux_arch_string (void)
2021
{
2022
  return the_low_target.arch_string;
2023
}
2024
 
2025
static struct target_ops linux_target_ops = {
2026
  linux_create_inferior,
2027
  linux_attach,
2028
  linux_kill,
2029
  linux_detach,
2030
  linux_join,
2031
  linux_thread_alive,
2032
  linux_resume,
2033
  linux_wait,
2034
  linux_fetch_registers,
2035
  linux_store_registers,
2036
  linux_read_memory,
2037
  linux_write_memory,
2038
  linux_look_up_symbols,
2039
  linux_request_interrupt,
2040
  linux_read_auxv,
2041
  linux_insert_watchpoint,
2042
  linux_remove_watchpoint,
2043
  linux_stopped_by_watchpoint,
2044
  linux_stopped_data_address,
2045
#if defined(__UCLIBC__) && defined(HAS_NOMMU)
2046
  linux_read_offsets,
2047
#else
2048
  NULL,
2049
#endif
2050
#ifdef USE_THREAD_DB
2051
  thread_db_get_tls_address,
2052
#else
2053
  NULL,
2054
#endif
2055
  linux_arch_string,
2056
  NULL,
2057
  hostio_last_error_from_errno,
2058
};
2059
 
2060
static void
2061
linux_init_signals ()
2062
{
2063
  /* FIXME drow/2002-06-09: As above, we should check with LinuxThreads
2064
     to find what the cancel signal actually is.  */
2065
  signal (__SIGRTMIN+1, SIG_IGN);
2066
}
2067
 
2068
void
2069
initialize_low (void)
2070
{
2071
  thread_db_active = 0;
2072
  set_target_ops (&linux_target_ops);
2073
  set_breakpoint_data (the_low_target.breakpoint,
2074
                       the_low_target.breakpoint_len);
2075
  init_registers ();
2076
  linux_init_signals ();
2077
  linux_test_for_tracefork ();
2078
}

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