* target.h (struct target_ops): Make to_has_all_memory,
[binutils-gdb.git] / gdb / linux-nat.c
1 /* GNU/Linux native-dependent code common to multiple platforms.
2
3 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
4 Free Software Foundation, Inc.
5
6 This file is part of GDB.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20
21 #include "defs.h"
22 #include "inferior.h"
23 #include "target.h"
24 #include "gdb_string.h"
25 #include "gdb_wait.h"
26 #include "gdb_assert.h"
27 #ifdef HAVE_TKILL_SYSCALL
28 #include <unistd.h>
29 #include <sys/syscall.h>
30 #endif
31 #include <sys/ptrace.h>
32 #include "linux-nat.h"
33 #include "linux-fork.h"
34 #include "gdbthread.h"
35 #include "gdbcmd.h"
36 #include "regcache.h"
37 #include "regset.h"
38 #include "inf-ptrace.h"
39 #include "auxv.h"
40 #include <sys/param.h> /* for MAXPATHLEN */
41 #include <sys/procfs.h> /* for elf_gregset etc. */
42 #include "elf-bfd.h" /* for elfcore_write_* */
43 #include "gregset.h" /* for gregset */
44 #include "gdbcore.h" /* for get_exec_file */
45 #include <ctype.h> /* for isdigit */
46 #include "gdbthread.h" /* for struct thread_info etc. */
47 #include "gdb_stat.h" /* for struct stat */
48 #include <fcntl.h> /* for O_RDONLY */
49 #include "inf-loop.h"
50 #include "event-loop.h"
51 #include "event-top.h"
52 #include <pwd.h>
53 #include <sys/types.h>
54 #include "gdb_dirent.h"
55 #include "xml-support.h"
56 #include "terminal.h"
57
58 #ifdef HAVE_PERSONALITY
59 # include <sys/personality.h>
60 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
61 # define ADDR_NO_RANDOMIZE 0x0040000
62 # endif
63 #endif /* HAVE_PERSONALITY */
64
65 /* This comment documents high-level logic of this file.
66
67 Waiting for events in sync mode
68 ===============================
69
70 When waiting for an event in a specific thread, we just use waitpid, passing
71 the specific pid, and not passing WNOHANG.
72
73 When waiting for an event in all threads, waitpid is not quite good. Prior to
74 version 2.4, Linux can either wait for event in main thread, or in secondary
75 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
76 miss an event. The solution is to use non-blocking waitpid, together with
77 sigsuspend. First, we use non-blocking waitpid to get an event in the main
78 process, if any. Second, we use non-blocking waitpid with the __WCLONED
79 flag to check for events in cloned processes. If nothing is found, we use
80 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
81 happened to a child process -- and SIGCHLD will be delivered both for events
82 in main debugged process and in cloned processes. As soon as we know there's
83 an event, we get back to calling nonblocking waitpid with and without __WCLONED.
84
85 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
86 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
87 blocked, the signal becomes pending and sigsuspend immediately
88 notices it and returns.
89
90 Waiting for events in async mode
91 ================================
92
93 In async mode, GDB should always be ready to handle both user input
94 and target events, so neither blocking waitpid nor sigsuspend are
95 viable options. Instead, we should asynchronously notify the GDB main
96 event loop whenever there's an unprocessed event from the target. We
97 detect asynchronous target events by handling SIGCHLD signals. To
98 notify the event loop about target events, the self-pipe trick is used
99 --- a pipe is registered as waitable event source in the event loop,
100 the event loop select/poll's on the read end of this pipe (as well on
101 other event sources, e.g., stdin), and the SIGCHLD handler writes a
102 byte to this pipe. This is more portable than relying on
103 pselect/ppoll, since on kernels that lack those syscalls, libc
104 emulates them with select/poll+sigprocmask, and that is racy
105 (a.k.a. plain broken).
106
107 Obviously, if we fail to notify the event loop if there's a target
108 event, it's bad. OTOH, if we notify the event loop when there's no
109 event from the target, linux_nat_wait will detect that there's no real
110 event to report, and return event of type TARGET_WAITKIND_IGNORE.
111 This is mostly harmless, but it will waste time and is better avoided.
112
113 The main design point is that every time GDB is outside linux-nat.c,
114 we have a SIGCHLD handler installed that is called when something
115 happens to the target and notifies the GDB event loop. Whenever GDB
116 core decides to handle the event, and calls into linux-nat.c, we
117 process things as in sync mode, except that the we never block in
118 sigsuspend.
119
120 While processing an event, we may end up momentarily blocked in
121 waitpid calls. Those waitpid calls, while blocking, are guarantied to
122 return quickly. E.g., in all-stop mode, before reporting to the core
123 that an LWP hit a breakpoint, all LWPs are stopped by sending them
124 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
125 Note that this is different from blocking indefinitely waiting for the
126 next event --- here, we're already handling an event.
127
128 Use of signals
129 ==============
130
131 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
132 signal is not entirely significant; we just need for a signal to be delivered,
133 so that we can intercept it. SIGSTOP's advantage is that it can not be
134 blocked. A disadvantage is that it is not a real-time signal, so it can only
135 be queued once; we do not keep track of other sources of SIGSTOP.
136
137 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
138 use them, because they have special behavior when the signal is generated -
139 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
140 kills the entire thread group.
141
142 A delivered SIGSTOP would stop the entire thread group, not just the thread we
143 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
144 cancel it (by PTRACE_CONT without passing SIGSTOP).
145
146 We could use a real-time signal instead. This would solve those problems; we
147 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
148 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
149 generates it, and there are races with trying to find a signal that is not
150 blocked. */
151
152 #ifndef O_LARGEFILE
153 #define O_LARGEFILE 0
154 #endif
155
156 /* If the system headers did not provide the constants, hard-code the normal
157 values. */
158 #ifndef PTRACE_EVENT_FORK
159
160 #define PTRACE_SETOPTIONS 0x4200
161 #define PTRACE_GETEVENTMSG 0x4201
162
163 /* options set using PTRACE_SETOPTIONS */
164 #define PTRACE_O_TRACESYSGOOD 0x00000001
165 #define PTRACE_O_TRACEFORK 0x00000002
166 #define PTRACE_O_TRACEVFORK 0x00000004
167 #define PTRACE_O_TRACECLONE 0x00000008
168 #define PTRACE_O_TRACEEXEC 0x00000010
169 #define PTRACE_O_TRACEVFORKDONE 0x00000020
170 #define PTRACE_O_TRACEEXIT 0x00000040
171
172 /* Wait extended result codes for the above trace options. */
173 #define PTRACE_EVENT_FORK 1
174 #define PTRACE_EVENT_VFORK 2
175 #define PTRACE_EVENT_CLONE 3
176 #define PTRACE_EVENT_EXEC 4
177 #define PTRACE_EVENT_VFORK_DONE 5
178 #define PTRACE_EVENT_EXIT 6
179
180 #endif /* PTRACE_EVENT_FORK */
181
182 /* We can't always assume that this flag is available, but all systems
183 with the ptrace event handlers also have __WALL, so it's safe to use
184 here. */
185 #ifndef __WALL
186 #define __WALL 0x40000000 /* Wait for any child. */
187 #endif
188
189 #ifndef PTRACE_GETSIGINFO
190 # define PTRACE_GETSIGINFO 0x4202
191 # define PTRACE_SETSIGINFO 0x4203
192 #endif
193
194 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
195 the use of the multi-threaded target. */
196 static struct target_ops *linux_ops;
197 static struct target_ops linux_ops_saved;
198
199 /* The method to call, if any, when a new thread is attached. */
200 static void (*linux_nat_new_thread) (ptid_t);
201
202 /* The method to call, if any, when the siginfo object needs to be
203 converted between the layout returned by ptrace, and the layout in
204 the architecture of the inferior. */
205 static int (*linux_nat_siginfo_fixup) (struct siginfo *,
206 gdb_byte *,
207 int);
208
209 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
210 Called by our to_xfer_partial. */
211 static LONGEST (*super_xfer_partial) (struct target_ops *,
212 enum target_object,
213 const char *, gdb_byte *,
214 const gdb_byte *,
215 ULONGEST, LONGEST);
216
217 static int debug_linux_nat;
218 static void
219 show_debug_linux_nat (struct ui_file *file, int from_tty,
220 struct cmd_list_element *c, const char *value)
221 {
222 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
223 value);
224 }
225
226 static int debug_linux_nat_async = 0;
227 static void
228 show_debug_linux_nat_async (struct ui_file *file, int from_tty,
229 struct cmd_list_element *c, const char *value)
230 {
231 fprintf_filtered (file, _("Debugging of GNU/Linux async lwp module is %s.\n"),
232 value);
233 }
234
235 static int disable_randomization = 1;
236
237 static void
238 show_disable_randomization (struct ui_file *file, int from_tty,
239 struct cmd_list_element *c, const char *value)
240 {
241 #ifdef HAVE_PERSONALITY
242 fprintf_filtered (file, _("\
243 Disabling randomization of debuggee's virtual address space is %s.\n"),
244 value);
245 #else /* !HAVE_PERSONALITY */
246 fputs_filtered (_("\
247 Disabling randomization of debuggee's virtual address space is unsupported on\n\
248 this platform.\n"), file);
249 #endif /* !HAVE_PERSONALITY */
250 }
251
252 static void
253 set_disable_randomization (char *args, int from_tty, struct cmd_list_element *c)
254 {
255 #ifndef HAVE_PERSONALITY
256 error (_("\
257 Disabling randomization of debuggee's virtual address space is unsupported on\n\
258 this platform."));
259 #endif /* !HAVE_PERSONALITY */
260 }
261
262 static int linux_parent_pid;
263
264 struct simple_pid_list
265 {
266 int pid;
267 int status;
268 struct simple_pid_list *next;
269 };
270 struct simple_pid_list *stopped_pids;
271
272 /* This variable is a tri-state flag: -1 for unknown, 0 if PTRACE_O_TRACEFORK
273 can not be used, 1 if it can. */
274
275 static int linux_supports_tracefork_flag = -1;
276
277 /* If we have PTRACE_O_TRACEFORK, this flag indicates whether we also have
278 PTRACE_O_TRACEVFORKDONE. */
279
280 static int linux_supports_tracevforkdone_flag = -1;
281
282 /* Async mode support */
283
284 /* Zero if the async mode, although enabled, is masked, which means
285 linux_nat_wait should behave as if async mode was off. */
286 static int linux_nat_async_mask_value = 1;
287
288 /* The read/write ends of the pipe registered as waitable file in the
289 event loop. */
290 static int linux_nat_event_pipe[2] = { -1, -1 };
291
292 /* Flush the event pipe. */
293
294 static void
295 async_file_flush (void)
296 {
297 int ret;
298 char buf;
299
300 do
301 {
302 ret = read (linux_nat_event_pipe[0], &buf, 1);
303 }
304 while (ret >= 0 || (ret == -1 && errno == EINTR));
305 }
306
307 /* Put something (anything, doesn't matter what, or how much) in event
308 pipe, so that the select/poll in the event-loop realizes we have
309 something to process. */
310
311 static void
312 async_file_mark (void)
313 {
314 int ret;
315
316 /* It doesn't really matter what the pipe contains, as long we end
317 up with something in it. Might as well flush the previous
318 left-overs. */
319 async_file_flush ();
320
321 do
322 {
323 ret = write (linux_nat_event_pipe[1], "+", 1);
324 }
325 while (ret == -1 && errno == EINTR);
326
327 /* Ignore EAGAIN. If the pipe is full, the event loop will already
328 be awakened anyway. */
329 }
330
331 static void linux_nat_async (void (*callback)
332 (enum inferior_event_type event_type, void *context),
333 void *context);
334 static int linux_nat_async_mask (int mask);
335 static int kill_lwp (int lwpid, int signo);
336
337 static int stop_callback (struct lwp_info *lp, void *data);
338
339 static void block_child_signals (sigset_t *prev_mask);
340 static void restore_child_signals_mask (sigset_t *prev_mask);
341 \f
342 /* Trivial list manipulation functions to keep track of a list of
343 new stopped processes. */
344 static void
345 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
346 {
347 struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
348 new_pid->pid = pid;
349 new_pid->status = status;
350 new_pid->next = *listp;
351 *listp = new_pid;
352 }
353
354 static int
355 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *status)
356 {
357 struct simple_pid_list **p;
358
359 for (p = listp; *p != NULL; p = &(*p)->next)
360 if ((*p)->pid == pid)
361 {
362 struct simple_pid_list *next = (*p)->next;
363 *status = (*p)->status;
364 xfree (*p);
365 *p = next;
366 return 1;
367 }
368 return 0;
369 }
370
371 static void
372 linux_record_stopped_pid (int pid, int status)
373 {
374 add_to_pid_list (&stopped_pids, pid, status);
375 }
376
377 \f
378 /* A helper function for linux_test_for_tracefork, called after fork (). */
379
380 static void
381 linux_tracefork_child (void)
382 {
383 int ret;
384
385 ptrace (PTRACE_TRACEME, 0, 0, 0);
386 kill (getpid (), SIGSTOP);
387 fork ();
388 _exit (0);
389 }
390
391 /* Wrapper function for waitpid which handles EINTR. */
392
393 static int
394 my_waitpid (int pid, int *status, int flags)
395 {
396 int ret;
397
398 do
399 {
400 ret = waitpid (pid, status, flags);
401 }
402 while (ret == -1 && errno == EINTR);
403
404 return ret;
405 }
406
407 /* Determine if PTRACE_O_TRACEFORK can be used to follow fork events.
408
409 First, we try to enable fork tracing on ORIGINAL_PID. If this fails,
410 we know that the feature is not available. This may change the tracing
411 options for ORIGINAL_PID, but we'll be setting them shortly anyway.
412
413 However, if it succeeds, we don't know for sure that the feature is
414 available; old versions of PTRACE_SETOPTIONS ignored unknown options. We
415 create a child process, attach to it, use PTRACE_SETOPTIONS to enable
416 fork tracing, and let it fork. If the process exits, we assume that we
417 can't use TRACEFORK; if we get the fork notification, and we can extract
418 the new child's PID, then we assume that we can. */
419
420 static void
421 linux_test_for_tracefork (int original_pid)
422 {
423 int child_pid, ret, status;
424 long second_pid;
425 sigset_t prev_mask;
426
427 /* We don't want those ptrace calls to be interrupted. */
428 block_child_signals (&prev_mask);
429
430 linux_supports_tracefork_flag = 0;
431 linux_supports_tracevforkdone_flag = 0;
432
433 ret = ptrace (PTRACE_SETOPTIONS, original_pid, 0, PTRACE_O_TRACEFORK);
434 if (ret != 0)
435 {
436 restore_child_signals_mask (&prev_mask);
437 return;
438 }
439
440 child_pid = fork ();
441 if (child_pid == -1)
442 perror_with_name (("fork"));
443
444 if (child_pid == 0)
445 linux_tracefork_child ();
446
447 ret = my_waitpid (child_pid, &status, 0);
448 if (ret == -1)
449 perror_with_name (("waitpid"));
450 else if (ret != child_pid)
451 error (_("linux_test_for_tracefork: waitpid: unexpected result %d."), ret);
452 if (! WIFSTOPPED (status))
453 error (_("linux_test_for_tracefork: waitpid: unexpected status %d."), status);
454
455 ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK);
456 if (ret != 0)
457 {
458 ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
459 if (ret != 0)
460 {
461 warning (_("linux_test_for_tracefork: failed to kill child"));
462 restore_child_signals_mask (&prev_mask);
463 return;
464 }
465
466 ret = my_waitpid (child_pid, &status, 0);
467 if (ret != child_pid)
468 warning (_("linux_test_for_tracefork: failed to wait for killed child"));
469 else if (!WIFSIGNALED (status))
470 warning (_("linux_test_for_tracefork: unexpected wait status 0x%x from "
471 "killed child"), status);
472
473 restore_child_signals_mask (&prev_mask);
474 return;
475 }
476
477 /* Check whether PTRACE_O_TRACEVFORKDONE is available. */
478 ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0,
479 PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORKDONE);
480 linux_supports_tracevforkdone_flag = (ret == 0);
481
482 ret = ptrace (PTRACE_CONT, child_pid, 0, 0);
483 if (ret != 0)
484 warning (_("linux_test_for_tracefork: failed to resume child"));
485
486 ret = my_waitpid (child_pid, &status, 0);
487
488 if (ret == child_pid && WIFSTOPPED (status)
489 && status >> 16 == PTRACE_EVENT_FORK)
490 {
491 second_pid = 0;
492 ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid);
493 if (ret == 0 && second_pid != 0)
494 {
495 int second_status;
496
497 linux_supports_tracefork_flag = 1;
498 my_waitpid (second_pid, &second_status, 0);
499 ret = ptrace (PTRACE_KILL, second_pid, 0, 0);
500 if (ret != 0)
501 warning (_("linux_test_for_tracefork: failed to kill second child"));
502 my_waitpid (second_pid, &status, 0);
503 }
504 }
505 else
506 warning (_("linux_test_for_tracefork: unexpected result from waitpid "
507 "(%d, status 0x%x)"), ret, status);
508
509 ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
510 if (ret != 0)
511 warning (_("linux_test_for_tracefork: failed to kill child"));
512 my_waitpid (child_pid, &status, 0);
513
514 restore_child_signals_mask (&prev_mask);
515 }
516
517 /* Return non-zero iff we have tracefork functionality available.
518 This function also sets linux_supports_tracefork_flag. */
519
520 static int
521 linux_supports_tracefork (int pid)
522 {
523 if (linux_supports_tracefork_flag == -1)
524 linux_test_for_tracefork (pid);
525 return linux_supports_tracefork_flag;
526 }
527
528 static int
529 linux_supports_tracevforkdone (int pid)
530 {
531 if (linux_supports_tracefork_flag == -1)
532 linux_test_for_tracefork (pid);
533 return linux_supports_tracevforkdone_flag;
534 }
535
536 \f
537 void
538 linux_enable_event_reporting (ptid_t ptid)
539 {
540 int pid = ptid_get_lwp (ptid);
541 int options;
542
543 if (pid == 0)
544 pid = ptid_get_pid (ptid);
545
546 if (! linux_supports_tracefork (pid))
547 return;
548
549 options = PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORK | PTRACE_O_TRACEEXEC
550 | PTRACE_O_TRACECLONE;
551 if (linux_supports_tracevforkdone (pid))
552 options |= PTRACE_O_TRACEVFORKDONE;
553
554 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to support
555 read-only process state. */
556
557 ptrace (PTRACE_SETOPTIONS, pid, 0, options);
558 }
559
560 static void
561 linux_child_post_attach (int pid)
562 {
563 linux_enable_event_reporting (pid_to_ptid (pid));
564 check_for_thread_db ();
565 }
566
567 static void
568 linux_child_post_startup_inferior (ptid_t ptid)
569 {
570 linux_enable_event_reporting (ptid);
571 check_for_thread_db ();
572 }
573
574 static int
575 linux_child_follow_fork (struct target_ops *ops, int follow_child)
576 {
577 sigset_t prev_mask;
578 int has_vforked;
579 int parent_pid, child_pid;
580
581 block_child_signals (&prev_mask);
582
583 has_vforked = (inferior_thread ()->pending_follow.kind
584 == TARGET_WAITKIND_VFORKED);
585 parent_pid = ptid_get_lwp (inferior_ptid);
586 if (parent_pid == 0)
587 parent_pid = ptid_get_pid (inferior_ptid);
588 child_pid = PIDGET (inferior_thread ()->pending_follow.value.related_pid);
589
590 if (! follow_child)
591 {
592 /* We're already attached to the parent, by default. */
593
594 /* Before detaching from the child, remove all breakpoints from
595 it. If we forked, then this has already been taken care of
596 by infrun.c. If we vforked however, any breakpoint inserted
597 in the parent is visible in the child, even those added while
598 stopped in a vfork catchpoint. This won't actually modify
599 the breakpoint list, but will physically remove the
600 breakpoints from the child. This will remove the breakpoints
601 from the parent also, but they'll be reinserted below. */
602 if (has_vforked)
603 detach_breakpoints (child_pid);
604
605 /* Detach new forked process? */
606 if (detach_fork)
607 {
608 if (info_verbose || debug_linux_nat)
609 {
610 target_terminal_ours ();
611 fprintf_filtered (gdb_stdlog,
612 "Detaching after fork from child process %d.\n",
613 child_pid);
614 }
615
616 ptrace (PTRACE_DETACH, child_pid, 0, 0);
617 }
618 else
619 {
620 struct fork_info *fp;
621 struct inferior *parent_inf, *child_inf;
622
623 /* Add process to GDB's tables. */
624 child_inf = add_inferior (child_pid);
625
626 parent_inf = current_inferior ();
627 child_inf->attach_flag = parent_inf->attach_flag;
628 copy_terminal_info (child_inf, parent_inf);
629
630 /* Retain child fork in ptrace (stopped) state. */
631 fp = find_fork_pid (child_pid);
632 if (!fp)
633 fp = add_fork (child_pid);
634 fork_save_infrun_state (fp, 0);
635 }
636
637 if (has_vforked)
638 {
639 gdb_assert (linux_supports_tracefork_flag >= 0);
640 if (linux_supports_tracevforkdone (0))
641 {
642 int status;
643
644 ptrace (PTRACE_CONT, parent_pid, 0, 0);
645 my_waitpid (parent_pid, &status, __WALL);
646 if ((status >> 16) != PTRACE_EVENT_VFORK_DONE)
647 warning (_("Unexpected waitpid result %06x when waiting for "
648 "vfork-done"), status);
649 }
650 else
651 {
652 /* We can't insert breakpoints until the child has
653 finished with the shared memory region. We need to
654 wait until that happens. Ideal would be to just
655 call:
656 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
657 - waitpid (parent_pid, &status, __WALL);
658 However, most architectures can't handle a syscall
659 being traced on the way out if it wasn't traced on
660 the way in.
661
662 We might also think to loop, continuing the child
663 until it exits or gets a SIGTRAP. One problem is
664 that the child might call ptrace with PTRACE_TRACEME.
665
666 There's no simple and reliable way to figure out when
667 the vforked child will be done with its copy of the
668 shared memory. We could step it out of the syscall,
669 two instructions, let it go, and then single-step the
670 parent once. When we have hardware single-step, this
671 would work; with software single-step it could still
672 be made to work but we'd have to be able to insert
673 single-step breakpoints in the child, and we'd have
674 to insert -just- the single-step breakpoint in the
675 parent. Very awkward.
676
677 In the end, the best we can do is to make sure it
678 runs for a little while. Hopefully it will be out of
679 range of any breakpoints we reinsert. Usually this
680 is only the single-step breakpoint at vfork's return
681 point. */
682
683 usleep (10000);
684 }
685
686 /* Since we vforked, breakpoints were removed in the parent
687 too. Put them back. */
688 reattach_breakpoints (parent_pid);
689 }
690 }
691 else
692 {
693 struct thread_info *tp;
694 struct inferior *parent_inf, *child_inf;
695
696 /* Before detaching from the parent, remove all breakpoints from it. */
697 remove_breakpoints ();
698
699 if (info_verbose || debug_linux_nat)
700 {
701 target_terminal_ours ();
702 fprintf_filtered (gdb_stdlog,
703 "Attaching after fork to child process %d.\n",
704 child_pid);
705 }
706
707 /* Add the new inferior first, so that the target_detach below
708 doesn't unpush the target. */
709
710 child_inf = add_inferior (child_pid);
711
712 parent_inf = current_inferior ();
713 child_inf->attach_flag = parent_inf->attach_flag;
714 copy_terminal_info (child_inf, parent_inf);
715
716 /* If we're vforking, we may want to hold on to the parent until
717 the child exits or execs. At exec time we can remove the old
718 breakpoints from the parent and detach it; at exit time we
719 could do the same (or even, sneakily, resume debugging it - the
720 child's exec has failed, or something similar).
721
722 This doesn't clean up "properly", because we can't call
723 target_detach, but that's OK; if the current target is "child",
724 then it doesn't need any further cleanups, and lin_lwp will
725 generally not encounter vfork (vfork is defined to fork
726 in libpthread.so).
727
728 The holding part is very easy if we have VFORKDONE events;
729 but keeping track of both processes is beyond GDB at the
730 moment. So we don't expose the parent to the rest of GDB.
731 Instead we quietly hold onto it until such time as we can
732 safely resume it. */
733
734 if (has_vforked)
735 {
736 linux_parent_pid = parent_pid;
737 detach_inferior (parent_pid);
738 }
739 else if (!detach_fork)
740 {
741 struct fork_info *fp;
742 /* Retain parent fork in ptrace (stopped) state. */
743 fp = find_fork_pid (parent_pid);
744 if (!fp)
745 fp = add_fork (parent_pid);
746 fork_save_infrun_state (fp, 0);
747
748 /* Also add an entry for the child fork. */
749 fp = find_fork_pid (child_pid);
750 if (!fp)
751 fp = add_fork (child_pid);
752 fork_save_infrun_state (fp, 0);
753 }
754 else
755 target_detach (NULL, 0);
756
757 inferior_ptid = ptid_build (child_pid, child_pid, 0);
758
759 linux_nat_switch_fork (inferior_ptid);
760 check_for_thread_db ();
761 }
762
763 restore_child_signals_mask (&prev_mask);
764 return 0;
765 }
766
767 \f
768 static void
769 linux_child_insert_fork_catchpoint (int pid)
770 {
771 if (! linux_supports_tracefork (pid))
772 error (_("Your system does not support fork catchpoints."));
773 }
774
775 static void
776 linux_child_insert_vfork_catchpoint (int pid)
777 {
778 if (!linux_supports_tracefork (pid))
779 error (_("Your system does not support vfork catchpoints."));
780 }
781
782 static void
783 linux_child_insert_exec_catchpoint (int pid)
784 {
785 if (!linux_supports_tracefork (pid))
786 error (_("Your system does not support exec catchpoints."));
787 }
788
789 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
790 are processes sharing the same VM space. A multi-threaded process
791 is basically a group of such processes. However, such a grouping
792 is almost entirely a user-space issue; the kernel doesn't enforce
793 such a grouping at all (this might change in the future). In
794 general, we'll rely on the threads library (i.e. the GNU/Linux
795 Threads library) to provide such a grouping.
796
797 It is perfectly well possible to write a multi-threaded application
798 without the assistance of a threads library, by using the clone
799 system call directly. This module should be able to give some
800 rudimentary support for debugging such applications if developers
801 specify the CLONE_PTRACE flag in the clone system call, and are
802 using the Linux kernel 2.4 or above.
803
804 Note that there are some peculiarities in GNU/Linux that affect
805 this code:
806
807 - In general one should specify the __WCLONE flag to waitpid in
808 order to make it report events for any of the cloned processes
809 (and leave it out for the initial process). However, if a cloned
810 process has exited the exit status is only reported if the
811 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
812 we cannot use it since GDB must work on older systems too.
813
814 - When a traced, cloned process exits and is waited for by the
815 debugger, the kernel reassigns it to the original parent and
816 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
817 library doesn't notice this, which leads to the "zombie problem":
818 When debugged a multi-threaded process that spawns a lot of
819 threads will run out of processes, even if the threads exit,
820 because the "zombies" stay around. */
821
822 /* List of known LWPs. */
823 struct lwp_info *lwp_list;
824 \f
825
826 /* Original signal mask. */
827 static sigset_t normal_mask;
828
829 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
830 _initialize_linux_nat. */
831 static sigset_t suspend_mask;
832
833 /* Signals to block to make that sigsuspend work. */
834 static sigset_t blocked_mask;
835
836 /* SIGCHLD action. */
837 struct sigaction sigchld_action;
838
839 /* Block child signals (SIGCHLD and linux threads signals), and store
840 the previous mask in PREV_MASK. */
841
842 static void
843 block_child_signals (sigset_t *prev_mask)
844 {
845 /* Make sure SIGCHLD is blocked. */
846 if (!sigismember (&blocked_mask, SIGCHLD))
847 sigaddset (&blocked_mask, SIGCHLD);
848
849 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
850 }
851
852 /* Restore child signals mask, previously returned by
853 block_child_signals. */
854
855 static void
856 restore_child_signals_mask (sigset_t *prev_mask)
857 {
858 sigprocmask (SIG_SETMASK, prev_mask, NULL);
859 }
860 \f
861
862 /* Prototypes for local functions. */
863 static int stop_wait_callback (struct lwp_info *lp, void *data);
864 static int linux_thread_alive (ptid_t ptid);
865 static char *linux_child_pid_to_exec_file (int pid);
866 static int cancel_breakpoint (struct lwp_info *lp);
867
868 \f
869 /* Convert wait status STATUS to a string. Used for printing debug
870 messages only. */
871
872 static char *
873 status_to_str (int status)
874 {
875 static char buf[64];
876
877 if (WIFSTOPPED (status))
878 snprintf (buf, sizeof (buf), "%s (stopped)",
879 strsignal (WSTOPSIG (status)));
880 else if (WIFSIGNALED (status))
881 snprintf (buf, sizeof (buf), "%s (terminated)",
882 strsignal (WSTOPSIG (status)));
883 else
884 snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status));
885
886 return buf;
887 }
888
889 /* Initialize the list of LWPs. Note that this module, contrary to
890 what GDB's generic threads layer does for its thread list,
891 re-initializes the LWP lists whenever we mourn or detach (which
892 doesn't involve mourning) the inferior. */
893
894 static void
895 init_lwp_list (void)
896 {
897 struct lwp_info *lp, *lpnext;
898
899 for (lp = lwp_list; lp; lp = lpnext)
900 {
901 lpnext = lp->next;
902 xfree (lp);
903 }
904
905 lwp_list = NULL;
906 }
907
908 /* Remove all LWPs belong to PID from the lwp list. */
909
910 static void
911 purge_lwp_list (int pid)
912 {
913 struct lwp_info *lp, *lpprev, *lpnext;
914
915 lpprev = NULL;
916
917 for (lp = lwp_list; lp; lp = lpnext)
918 {
919 lpnext = lp->next;
920
921 if (ptid_get_pid (lp->ptid) == pid)
922 {
923 if (lp == lwp_list)
924 lwp_list = lp->next;
925 else
926 lpprev->next = lp->next;
927
928 xfree (lp);
929 }
930 else
931 lpprev = lp;
932 }
933 }
934
935 /* Return the number of known LWPs in the tgid given by PID. */
936
937 static int
938 num_lwps (int pid)
939 {
940 int count = 0;
941 struct lwp_info *lp;
942
943 for (lp = lwp_list; lp; lp = lp->next)
944 if (ptid_get_pid (lp->ptid) == pid)
945 count++;
946
947 return count;
948 }
949
950 /* Add the LWP specified by PID to the list. Return a pointer to the
951 structure describing the new LWP. The LWP should already be stopped
952 (with an exception for the very first LWP). */
953
954 static struct lwp_info *
955 add_lwp (ptid_t ptid)
956 {
957 struct lwp_info *lp;
958
959 gdb_assert (is_lwp (ptid));
960
961 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
962
963 memset (lp, 0, sizeof (struct lwp_info));
964
965 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
966
967 lp->ptid = ptid;
968
969 lp->next = lwp_list;
970 lwp_list = lp;
971
972 if (num_lwps (GET_PID (ptid)) > 1 && linux_nat_new_thread != NULL)
973 linux_nat_new_thread (ptid);
974
975 return lp;
976 }
977
978 /* Remove the LWP specified by PID from the list. */
979
980 static void
981 delete_lwp (ptid_t ptid)
982 {
983 struct lwp_info *lp, *lpprev;
984
985 lpprev = NULL;
986
987 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
988 if (ptid_equal (lp->ptid, ptid))
989 break;
990
991 if (!lp)
992 return;
993
994 if (lpprev)
995 lpprev->next = lp->next;
996 else
997 lwp_list = lp->next;
998
999 xfree (lp);
1000 }
1001
1002 /* Return a pointer to the structure describing the LWP corresponding
1003 to PID. If no corresponding LWP could be found, return NULL. */
1004
1005 static struct lwp_info *
1006 find_lwp_pid (ptid_t ptid)
1007 {
1008 struct lwp_info *lp;
1009 int lwp;
1010
1011 if (is_lwp (ptid))
1012 lwp = GET_LWP (ptid);
1013 else
1014 lwp = GET_PID (ptid);
1015
1016 for (lp = lwp_list; lp; lp = lp->next)
1017 if (lwp == GET_LWP (lp->ptid))
1018 return lp;
1019
1020 return NULL;
1021 }
1022
1023 /* Returns true if PTID matches filter FILTER. FILTER can be the wild
1024 card MINUS_ONE_PTID (all ptid match it); can be a ptid representing
1025 a process (ptid_is_pid returns true), in which case, all lwps of
1026 that give process match, lwps of other process do not; or, it can
1027 represent a specific thread, in which case, only that thread will
1028 match true. PTID must represent an LWP, it can never be a wild
1029 card. */
1030
1031 static int
1032 ptid_match (ptid_t ptid, ptid_t filter)
1033 {
1034 /* Since both parameters have the same type, prevent easy mistakes
1035 from happening. */
1036 gdb_assert (!ptid_equal (ptid, minus_one_ptid)
1037 && !ptid_equal (ptid, null_ptid));
1038
1039 if (ptid_equal (filter, minus_one_ptid))
1040 return 1;
1041 if (ptid_is_pid (filter)
1042 && ptid_get_pid (ptid) == ptid_get_pid (filter))
1043 return 1;
1044 else if (ptid_equal (ptid, filter))
1045 return 1;
1046
1047 return 0;
1048 }
1049
1050 /* Call CALLBACK with its second argument set to DATA for every LWP in
1051 the list. If CALLBACK returns 1 for a particular LWP, return a
1052 pointer to the structure describing that LWP immediately.
1053 Otherwise return NULL. */
1054
1055 struct lwp_info *
1056 iterate_over_lwps (ptid_t filter,
1057 int (*callback) (struct lwp_info *, void *),
1058 void *data)
1059 {
1060 struct lwp_info *lp, *lpnext;
1061
1062 for (lp = lwp_list; lp; lp = lpnext)
1063 {
1064 lpnext = lp->next;
1065
1066 if (ptid_match (lp->ptid, filter))
1067 {
1068 if ((*callback) (lp, data))
1069 return lp;
1070 }
1071 }
1072
1073 return NULL;
1074 }
1075
1076 /* Update our internal state when changing from one fork (checkpoint,
1077 et cetera) to another indicated by NEW_PTID. We can only switch
1078 single-threaded applications, so we only create one new LWP, and
1079 the previous list is discarded. */
1080
1081 void
1082 linux_nat_switch_fork (ptid_t new_ptid)
1083 {
1084 struct lwp_info *lp;
1085
1086 init_lwp_list ();
1087 lp = add_lwp (new_ptid);
1088 lp->stopped = 1;
1089
1090 init_thread_list ();
1091 add_thread_silent (new_ptid);
1092 }
1093
1094 /* Handle the exit of a single thread LP. */
1095
1096 static void
1097 exit_lwp (struct lwp_info *lp)
1098 {
1099 struct thread_info *th = find_thread_ptid (lp->ptid);
1100
1101 if (th)
1102 {
1103 if (print_thread_events)
1104 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
1105
1106 delete_thread (lp->ptid);
1107 }
1108
1109 delete_lwp (lp->ptid);
1110 }
1111
1112 /* Return an lwp's tgid, found in `/proc/PID/status'. */
1113
1114 int
1115 linux_proc_get_tgid (int lwpid)
1116 {
1117 FILE *status_file;
1118 char buf[100];
1119 int tgid = -1;
1120
1121 snprintf (buf, sizeof (buf), "/proc/%d/status", (int) lwpid);
1122 status_file = fopen (buf, "r");
1123 if (status_file != NULL)
1124 {
1125 while (fgets (buf, sizeof (buf), status_file))
1126 {
1127 if (strncmp (buf, "Tgid:", 5) == 0)
1128 {
1129 tgid = strtoul (buf + strlen ("Tgid:"), NULL, 10);
1130 break;
1131 }
1132 }
1133
1134 fclose (status_file);
1135 }
1136
1137 return tgid;
1138 }
1139
1140 /* Detect `T (stopped)' in `/proc/PID/status'.
1141 Other states including `T (tracing stop)' are reported as false. */
1142
1143 static int
1144 pid_is_stopped (pid_t pid)
1145 {
1146 FILE *status_file;
1147 char buf[100];
1148 int retval = 0;
1149
1150 snprintf (buf, sizeof (buf), "/proc/%d/status", (int) pid);
1151 status_file = fopen (buf, "r");
1152 if (status_file != NULL)
1153 {
1154 int have_state = 0;
1155
1156 while (fgets (buf, sizeof (buf), status_file))
1157 {
1158 if (strncmp (buf, "State:", 6) == 0)
1159 {
1160 have_state = 1;
1161 break;
1162 }
1163 }
1164 if (have_state && strstr (buf, "T (stopped)") != NULL)
1165 retval = 1;
1166 fclose (status_file);
1167 }
1168 return retval;
1169 }
1170
1171 /* Wait for the LWP specified by LP, which we have just attached to.
1172 Returns a wait status for that LWP, to cache. */
1173
1174 static int
1175 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
1176 int *signalled)
1177 {
1178 pid_t new_pid, pid = GET_LWP (ptid);
1179 int status;
1180
1181 if (pid_is_stopped (pid))
1182 {
1183 if (debug_linux_nat)
1184 fprintf_unfiltered (gdb_stdlog,
1185 "LNPAW: Attaching to a stopped process\n");
1186
1187 /* The process is definitely stopped. It is in a job control
1188 stop, unless the kernel predates the TASK_STOPPED /
1189 TASK_TRACED distinction, in which case it might be in a
1190 ptrace stop. Make sure it is in a ptrace stop; from there we
1191 can kill it, signal it, et cetera.
1192
1193 First make sure there is a pending SIGSTOP. Since we are
1194 already attached, the process can not transition from stopped
1195 to running without a PTRACE_CONT; so we know this signal will
1196 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1197 probably already in the queue (unless this kernel is old
1198 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1199 is not an RT signal, it can only be queued once. */
1200 kill_lwp (pid, SIGSTOP);
1201
1202 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1203 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1204 ptrace (PTRACE_CONT, pid, 0, 0);
1205 }
1206
1207 /* Make sure the initial process is stopped. The user-level threads
1208 layer might want to poke around in the inferior, and that won't
1209 work if things haven't stabilized yet. */
1210 new_pid = my_waitpid (pid, &status, 0);
1211 if (new_pid == -1 && errno == ECHILD)
1212 {
1213 if (first)
1214 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
1215
1216 /* Try again with __WCLONE to check cloned processes. */
1217 new_pid = my_waitpid (pid, &status, __WCLONE);
1218 *cloned = 1;
1219 }
1220
1221 gdb_assert (pid == new_pid && WIFSTOPPED (status));
1222
1223 if (WSTOPSIG (status) != SIGSTOP)
1224 {
1225 *signalled = 1;
1226 if (debug_linux_nat)
1227 fprintf_unfiltered (gdb_stdlog,
1228 "LNPAW: Received %s after attaching\n",
1229 status_to_str (status));
1230 }
1231
1232 return status;
1233 }
1234
1235 /* Attach to the LWP specified by PID. Return 0 if successful or -1
1236 if the new LWP could not be attached. */
1237
1238 int
1239 lin_lwp_attach_lwp (ptid_t ptid)
1240 {
1241 struct lwp_info *lp;
1242 sigset_t prev_mask;
1243
1244 gdb_assert (is_lwp (ptid));
1245
1246 block_child_signals (&prev_mask);
1247
1248 lp = find_lwp_pid (ptid);
1249
1250 /* We assume that we're already attached to any LWP that has an id
1251 equal to the overall process id, and to any LWP that is already
1252 in our list of LWPs. If we're not seeing exit events from threads
1253 and we've had PID wraparound since we last tried to stop all threads,
1254 this assumption might be wrong; fortunately, this is very unlikely
1255 to happen. */
1256 if (GET_LWP (ptid) != GET_PID (ptid) && lp == NULL)
1257 {
1258 int status, cloned = 0, signalled = 0;
1259
1260 if (ptrace (PTRACE_ATTACH, GET_LWP (ptid), 0, 0) < 0)
1261 {
1262 /* If we fail to attach to the thread, issue a warning,
1263 but continue. One way this can happen is if thread
1264 creation is interrupted; as of Linux kernel 2.6.19, a
1265 bug may place threads in the thread list and then fail
1266 to create them. */
1267 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1268 safe_strerror (errno));
1269 restore_child_signals_mask (&prev_mask);
1270 return -1;
1271 }
1272
1273 if (debug_linux_nat)
1274 fprintf_unfiltered (gdb_stdlog,
1275 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1276 target_pid_to_str (ptid));
1277
1278 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1279 lp = add_lwp (ptid);
1280 lp->stopped = 1;
1281 lp->cloned = cloned;
1282 lp->signalled = signalled;
1283 if (WSTOPSIG (status) != SIGSTOP)
1284 {
1285 lp->resumed = 1;
1286 lp->status = status;
1287 }
1288
1289 target_post_attach (GET_LWP (lp->ptid));
1290
1291 if (debug_linux_nat)
1292 {
1293 fprintf_unfiltered (gdb_stdlog,
1294 "LLAL: waitpid %s received %s\n",
1295 target_pid_to_str (ptid),
1296 status_to_str (status));
1297 }
1298 }
1299 else
1300 {
1301 /* We assume that the LWP representing the original process is
1302 already stopped. Mark it as stopped in the data structure
1303 that the GNU/linux ptrace layer uses to keep track of
1304 threads. Note that this won't have already been done since
1305 the main thread will have, we assume, been stopped by an
1306 attach from a different layer. */
1307 if (lp == NULL)
1308 lp = add_lwp (ptid);
1309 lp->stopped = 1;
1310 }
1311
1312 restore_child_signals_mask (&prev_mask);
1313 return 0;
1314 }
1315
1316 static void
1317 linux_nat_create_inferior (struct target_ops *ops,
1318 char *exec_file, char *allargs, char **env,
1319 int from_tty)
1320 {
1321 #ifdef HAVE_PERSONALITY
1322 int personality_orig = 0, personality_set = 0;
1323 #endif /* HAVE_PERSONALITY */
1324
1325 /* The fork_child mechanism is synchronous and calls target_wait, so
1326 we have to mask the async mode. */
1327
1328 #ifdef HAVE_PERSONALITY
1329 if (disable_randomization)
1330 {
1331 errno = 0;
1332 personality_orig = personality (0xffffffff);
1333 if (errno == 0 && !(personality_orig & ADDR_NO_RANDOMIZE))
1334 {
1335 personality_set = 1;
1336 personality (personality_orig | ADDR_NO_RANDOMIZE);
1337 }
1338 if (errno != 0 || (personality_set
1339 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE)))
1340 warning (_("Error disabling address space randomization: %s"),
1341 safe_strerror (errno));
1342 }
1343 #endif /* HAVE_PERSONALITY */
1344
1345 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1346
1347 #ifdef HAVE_PERSONALITY
1348 if (personality_set)
1349 {
1350 errno = 0;
1351 personality (personality_orig);
1352 if (errno != 0)
1353 warning (_("Error restoring address space randomization: %s"),
1354 safe_strerror (errno));
1355 }
1356 #endif /* HAVE_PERSONALITY */
1357 }
1358
1359 static void
1360 linux_nat_attach (struct target_ops *ops, char *args, int from_tty)
1361 {
1362 struct lwp_info *lp;
1363 int status;
1364 ptid_t ptid;
1365
1366 linux_ops->to_attach (ops, args, from_tty);
1367
1368 /* The ptrace base target adds the main thread with (pid,0,0)
1369 format. Decorate it with lwp info. */
1370 ptid = BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid));
1371 thread_change_ptid (inferior_ptid, ptid);
1372
1373 /* Add the initial process as the first LWP to the list. */
1374 lp = add_lwp (ptid);
1375
1376 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1377 &lp->signalled);
1378 lp->stopped = 1;
1379
1380 /* Save the wait status to report later. */
1381 lp->resumed = 1;
1382 if (debug_linux_nat)
1383 fprintf_unfiltered (gdb_stdlog,
1384 "LNA: waitpid %ld, saving status %s\n",
1385 (long) GET_PID (lp->ptid), status_to_str (status));
1386
1387 lp->status = status;
1388
1389 if (target_can_async_p ())
1390 target_async (inferior_event_handler, 0);
1391 }
1392
1393 /* Get pending status of LP. */
1394 static int
1395 get_pending_status (struct lwp_info *lp, int *status)
1396 {
1397 struct target_waitstatus last;
1398 ptid_t last_ptid;
1399
1400 get_last_target_status (&last_ptid, &last);
1401
1402 /* If this lwp is the ptid that GDB is processing an event from, the
1403 signal will be in stop_signal. Otherwise, we may cache pending
1404 events in lp->status while trying to stop all threads (see
1405 stop_wait_callback). */
1406
1407 *status = 0;
1408
1409 if (non_stop)
1410 {
1411 enum target_signal signo = TARGET_SIGNAL_0;
1412
1413 if (is_executing (lp->ptid))
1414 {
1415 /* If the core thought this lwp was executing --- e.g., the
1416 executing property hasn't been updated yet, but the
1417 thread has been stopped with a stop_callback /
1418 stop_wait_callback sequence (see linux_nat_detach for
1419 example) --- we can only have pending events in the local
1420 queue. */
1421 signo = target_signal_from_host (WSTOPSIG (lp->status));
1422 }
1423 else
1424 {
1425 /* If the core knows the thread is not executing, then we
1426 have the last signal recorded in
1427 thread_info->stop_signal. */
1428
1429 struct thread_info *tp = find_thread_ptid (lp->ptid);
1430 signo = tp->stop_signal;
1431 }
1432
1433 if (signo != TARGET_SIGNAL_0
1434 && !signal_pass_state (signo))
1435 {
1436 if (debug_linux_nat)
1437 fprintf_unfiltered (gdb_stdlog, "\
1438 GPT: lwp %s had signal %s, but it is in no pass state\n",
1439 target_pid_to_str (lp->ptid),
1440 target_signal_to_string (signo));
1441 }
1442 else
1443 {
1444 if (signo != TARGET_SIGNAL_0)
1445 *status = W_STOPCODE (target_signal_to_host (signo));
1446
1447 if (debug_linux_nat)
1448 fprintf_unfiltered (gdb_stdlog,
1449 "GPT: lwp %s as pending signal %s\n",
1450 target_pid_to_str (lp->ptid),
1451 target_signal_to_string (signo));
1452 }
1453 }
1454 else
1455 {
1456 if (GET_LWP (lp->ptid) == GET_LWP (last_ptid))
1457 {
1458 struct thread_info *tp = find_thread_ptid (lp->ptid);
1459 if (tp->stop_signal != TARGET_SIGNAL_0
1460 && signal_pass_state (tp->stop_signal))
1461 *status = W_STOPCODE (target_signal_to_host (tp->stop_signal));
1462 }
1463 else
1464 *status = lp->status;
1465 }
1466
1467 return 0;
1468 }
1469
1470 static int
1471 detach_callback (struct lwp_info *lp, void *data)
1472 {
1473 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1474
1475 if (debug_linux_nat && lp->status)
1476 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1477 strsignal (WSTOPSIG (lp->status)),
1478 target_pid_to_str (lp->ptid));
1479
1480 /* If there is a pending SIGSTOP, get rid of it. */
1481 if (lp->signalled)
1482 {
1483 if (debug_linux_nat)
1484 fprintf_unfiltered (gdb_stdlog,
1485 "DC: Sending SIGCONT to %s\n",
1486 target_pid_to_str (lp->ptid));
1487
1488 kill_lwp (GET_LWP (lp->ptid), SIGCONT);
1489 lp->signalled = 0;
1490 }
1491
1492 /* We don't actually detach from the LWP that has an id equal to the
1493 overall process id just yet. */
1494 if (GET_LWP (lp->ptid) != GET_PID (lp->ptid))
1495 {
1496 int status = 0;
1497
1498 /* Pass on any pending signal for this LWP. */
1499 get_pending_status (lp, &status);
1500
1501 errno = 0;
1502 if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0,
1503 WSTOPSIG (status)) < 0)
1504 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1505 safe_strerror (errno));
1506
1507 if (debug_linux_nat)
1508 fprintf_unfiltered (gdb_stdlog,
1509 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1510 target_pid_to_str (lp->ptid),
1511 strsignal (WSTOPSIG (status)));
1512
1513 delete_lwp (lp->ptid);
1514 }
1515
1516 return 0;
1517 }
1518
1519 static void
1520 linux_nat_detach (struct target_ops *ops, char *args, int from_tty)
1521 {
1522 int pid;
1523 int status;
1524 enum target_signal sig;
1525 struct lwp_info *main_lwp;
1526
1527 pid = GET_PID (inferior_ptid);
1528
1529 if (target_can_async_p ())
1530 linux_nat_async (NULL, 0);
1531
1532 /* Stop all threads before detaching. ptrace requires that the
1533 thread is stopped to sucessfully detach. */
1534 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1535 /* ... and wait until all of them have reported back that
1536 they're no longer running. */
1537 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1538
1539 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1540
1541 /* Only the initial process should be left right now. */
1542 gdb_assert (num_lwps (GET_PID (inferior_ptid)) == 1);
1543
1544 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1545
1546 /* Pass on any pending signal for the last LWP. */
1547 if ((args == NULL || *args == '\0')
1548 && get_pending_status (main_lwp, &status) != -1
1549 && WIFSTOPPED (status))
1550 {
1551 /* Put the signal number in ARGS so that inf_ptrace_detach will
1552 pass it along with PTRACE_DETACH. */
1553 args = alloca (8);
1554 sprintf (args, "%d", (int) WSTOPSIG (status));
1555 fprintf_unfiltered (gdb_stdlog,
1556 "LND: Sending signal %s to %s\n",
1557 args,
1558 target_pid_to_str (main_lwp->ptid));
1559 }
1560
1561 delete_lwp (main_lwp->ptid);
1562
1563 if (forks_exist_p ())
1564 {
1565 /* Multi-fork case. The current inferior_ptid is being detached
1566 from, but there are other viable forks to debug. Detach from
1567 the current fork, and context-switch to the first
1568 available. */
1569 linux_fork_detach (args, from_tty);
1570
1571 if (non_stop && target_can_async_p ())
1572 target_async (inferior_event_handler, 0);
1573 }
1574 else
1575 linux_ops->to_detach (ops, args, from_tty);
1576 }
1577
1578 /* Resume LP. */
1579
1580 static int
1581 resume_callback (struct lwp_info *lp, void *data)
1582 {
1583 if (lp->stopped && lp->status == 0)
1584 {
1585 if (debug_linux_nat)
1586 fprintf_unfiltered (gdb_stdlog,
1587 "RC: PTRACE_CONT %s, 0, 0 (resuming sibling)\n",
1588 target_pid_to_str (lp->ptid));
1589
1590 linux_ops->to_resume (linux_ops,
1591 pid_to_ptid (GET_LWP (lp->ptid)),
1592 0, TARGET_SIGNAL_0);
1593 if (debug_linux_nat)
1594 fprintf_unfiltered (gdb_stdlog,
1595 "RC: PTRACE_CONT %s, 0, 0 (resume sibling)\n",
1596 target_pid_to_str (lp->ptid));
1597 lp->stopped = 0;
1598 lp->step = 0;
1599 memset (&lp->siginfo, 0, sizeof (lp->siginfo));
1600 }
1601 else if (lp->stopped && debug_linux_nat)
1602 fprintf_unfiltered (gdb_stdlog, "RC: Not resuming sibling %s (has pending)\n",
1603 target_pid_to_str (lp->ptid));
1604 else if (debug_linux_nat)
1605 fprintf_unfiltered (gdb_stdlog, "RC: Not resuming sibling %s (not stopped)\n",
1606 target_pid_to_str (lp->ptid));
1607
1608 return 0;
1609 }
1610
1611 static int
1612 resume_clear_callback (struct lwp_info *lp, void *data)
1613 {
1614 lp->resumed = 0;
1615 return 0;
1616 }
1617
1618 static int
1619 resume_set_callback (struct lwp_info *lp, void *data)
1620 {
1621 lp->resumed = 1;
1622 return 0;
1623 }
1624
1625 static void
1626 linux_nat_resume (struct target_ops *ops,
1627 ptid_t ptid, int step, enum target_signal signo)
1628 {
1629 sigset_t prev_mask;
1630 struct lwp_info *lp;
1631 int resume_many;
1632
1633 if (debug_linux_nat)
1634 fprintf_unfiltered (gdb_stdlog,
1635 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1636 step ? "step" : "resume",
1637 target_pid_to_str (ptid),
1638 signo ? strsignal (signo) : "0",
1639 target_pid_to_str (inferior_ptid));
1640
1641 block_child_signals (&prev_mask);
1642
1643 /* A specific PTID means `step only this process id'. */
1644 resume_many = (ptid_equal (minus_one_ptid, ptid)
1645 || ptid_is_pid (ptid));
1646
1647 if (!non_stop)
1648 {
1649 /* Mark the lwps we're resuming as resumed. */
1650 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
1651 iterate_over_lwps (ptid, resume_set_callback, NULL);
1652 }
1653 else
1654 iterate_over_lwps (minus_one_ptid, resume_set_callback, NULL);
1655
1656 /* See if it's the current inferior that should be handled
1657 specially. */
1658 if (resume_many)
1659 lp = find_lwp_pid (inferior_ptid);
1660 else
1661 lp = find_lwp_pid (ptid);
1662 gdb_assert (lp != NULL);
1663
1664 /* Remember if we're stepping. */
1665 lp->step = step;
1666
1667 /* If we have a pending wait status for this thread, there is no
1668 point in resuming the process. But first make sure that
1669 linux_nat_wait won't preemptively handle the event - we
1670 should never take this short-circuit if we are going to
1671 leave LP running, since we have skipped resuming all the
1672 other threads. This bit of code needs to be synchronized
1673 with linux_nat_wait. */
1674
1675 if (lp->status && WIFSTOPPED (lp->status))
1676 {
1677 int saved_signo;
1678 struct inferior *inf;
1679
1680 inf = find_inferior_pid (ptid_get_pid (lp->ptid));
1681 gdb_assert (inf);
1682 saved_signo = target_signal_from_host (WSTOPSIG (lp->status));
1683
1684 /* Defer to common code if we're gaining control of the
1685 inferior. */
1686 if (inf->stop_soon == NO_STOP_QUIETLY
1687 && signal_stop_state (saved_signo) == 0
1688 && signal_print_state (saved_signo) == 0
1689 && signal_pass_state (saved_signo) == 1)
1690 {
1691 if (debug_linux_nat)
1692 fprintf_unfiltered (gdb_stdlog,
1693 "LLR: Not short circuiting for ignored "
1694 "status 0x%x\n", lp->status);
1695
1696 /* FIXME: What should we do if we are supposed to continue
1697 this thread with a signal? */
1698 gdb_assert (signo == TARGET_SIGNAL_0);
1699 signo = saved_signo;
1700 lp->status = 0;
1701 }
1702 }
1703
1704 if (lp->status)
1705 {
1706 /* FIXME: What should we do if we are supposed to continue
1707 this thread with a signal? */
1708 gdb_assert (signo == TARGET_SIGNAL_0);
1709
1710 if (debug_linux_nat)
1711 fprintf_unfiltered (gdb_stdlog,
1712 "LLR: Short circuiting for status 0x%x\n",
1713 lp->status);
1714
1715 restore_child_signals_mask (&prev_mask);
1716 if (target_can_async_p ())
1717 {
1718 target_async (inferior_event_handler, 0);
1719 /* Tell the event loop we have something to process. */
1720 async_file_mark ();
1721 }
1722 return;
1723 }
1724
1725 /* Mark LWP as not stopped to prevent it from being continued by
1726 resume_callback. */
1727 lp->stopped = 0;
1728
1729 if (resume_many)
1730 iterate_over_lwps (ptid, resume_callback, NULL);
1731
1732 /* Convert to something the lower layer understands. */
1733 ptid = pid_to_ptid (GET_LWP (lp->ptid));
1734
1735 linux_ops->to_resume (linux_ops, ptid, step, signo);
1736 memset (&lp->siginfo, 0, sizeof (lp->siginfo));
1737
1738 if (debug_linux_nat)
1739 fprintf_unfiltered (gdb_stdlog,
1740 "LLR: %s %s, %s (resume event thread)\n",
1741 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1742 target_pid_to_str (ptid),
1743 signo ? strsignal (signo) : "0");
1744
1745 restore_child_signals_mask (&prev_mask);
1746 if (target_can_async_p ())
1747 target_async (inferior_event_handler, 0);
1748 }
1749
1750 /* Issue kill to specified lwp. */
1751
1752 static int tkill_failed;
1753
1754 static int
1755 kill_lwp (int lwpid, int signo)
1756 {
1757 errno = 0;
1758
1759 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1760 fails, then we are not using nptl threads and we should be using kill. */
1761
1762 #ifdef HAVE_TKILL_SYSCALL
1763 if (!tkill_failed)
1764 {
1765 int ret = syscall (__NR_tkill, lwpid, signo);
1766 if (errno != ENOSYS)
1767 return ret;
1768 errno = 0;
1769 tkill_failed = 1;
1770 }
1771 #endif
1772
1773 return kill (lwpid, signo);
1774 }
1775
1776 /* Handle a GNU/Linux extended wait response. If we see a clone
1777 event, we need to add the new LWP to our list (and not report the
1778 trap to higher layers). This function returns non-zero if the
1779 event should be ignored and we should wait again. If STOPPING is
1780 true, the new LWP remains stopped, otherwise it is continued. */
1781
1782 static int
1783 linux_handle_extended_wait (struct lwp_info *lp, int status,
1784 int stopping)
1785 {
1786 int pid = GET_LWP (lp->ptid);
1787 struct target_waitstatus *ourstatus = &lp->waitstatus;
1788 struct lwp_info *new_lp = NULL;
1789 int event = status >> 16;
1790
1791 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1792 || event == PTRACE_EVENT_CLONE)
1793 {
1794 unsigned long new_pid;
1795 int ret;
1796
1797 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
1798
1799 /* If we haven't already seen the new PID stop, wait for it now. */
1800 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
1801 {
1802 /* The new child has a pending SIGSTOP. We can't affect it until it
1803 hits the SIGSTOP, but we're already attached. */
1804 ret = my_waitpid (new_pid, &status,
1805 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
1806 if (ret == -1)
1807 perror_with_name (_("waiting for new child"));
1808 else if (ret != new_pid)
1809 internal_error (__FILE__, __LINE__,
1810 _("wait returned unexpected PID %d"), ret);
1811 else if (!WIFSTOPPED (status))
1812 internal_error (__FILE__, __LINE__,
1813 _("wait returned unexpected status 0x%x"), status);
1814 }
1815
1816 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
1817
1818 if (event == PTRACE_EVENT_FORK)
1819 ourstatus->kind = TARGET_WAITKIND_FORKED;
1820 else if (event == PTRACE_EVENT_VFORK)
1821 ourstatus->kind = TARGET_WAITKIND_VFORKED;
1822 else
1823 {
1824 struct cleanup *old_chain;
1825
1826 ourstatus->kind = TARGET_WAITKIND_IGNORE;
1827 new_lp = add_lwp (BUILD_LWP (new_pid, GET_PID (lp->ptid)));
1828 new_lp->cloned = 1;
1829 new_lp->stopped = 1;
1830
1831 if (WSTOPSIG (status) != SIGSTOP)
1832 {
1833 /* This can happen if someone starts sending signals to
1834 the new thread before it gets a chance to run, which
1835 have a lower number than SIGSTOP (e.g. SIGUSR1).
1836 This is an unlikely case, and harder to handle for
1837 fork / vfork than for clone, so we do not try - but
1838 we handle it for clone events here. We'll send
1839 the other signal on to the thread below. */
1840
1841 new_lp->signalled = 1;
1842 }
1843 else
1844 status = 0;
1845
1846 if (non_stop)
1847 {
1848 /* Add the new thread to GDB's lists as soon as possible
1849 so that:
1850
1851 1) the frontend doesn't have to wait for a stop to
1852 display them, and,
1853
1854 2) we tag it with the correct running state. */
1855
1856 /* If the thread_db layer is active, let it know about
1857 this new thread, and add it to GDB's list. */
1858 if (!thread_db_attach_lwp (new_lp->ptid))
1859 {
1860 /* We're not using thread_db. Add it to GDB's
1861 list. */
1862 target_post_attach (GET_LWP (new_lp->ptid));
1863 add_thread (new_lp->ptid);
1864 }
1865
1866 if (!stopping)
1867 {
1868 set_running (new_lp->ptid, 1);
1869 set_executing (new_lp->ptid, 1);
1870 }
1871 }
1872
1873 if (!stopping)
1874 {
1875 new_lp->stopped = 0;
1876 new_lp->resumed = 1;
1877 ptrace (PTRACE_CONT, new_pid, 0,
1878 status ? WSTOPSIG (status) : 0);
1879 }
1880
1881 if (debug_linux_nat)
1882 fprintf_unfiltered (gdb_stdlog,
1883 "LHEW: Got clone event from LWP %ld, resuming\n",
1884 GET_LWP (lp->ptid));
1885 ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
1886
1887 return 1;
1888 }
1889
1890 return 0;
1891 }
1892
1893 if (event == PTRACE_EVENT_EXEC)
1894 {
1895 if (debug_linux_nat)
1896 fprintf_unfiltered (gdb_stdlog,
1897 "LHEW: Got exec event from LWP %ld\n",
1898 GET_LWP (lp->ptid));
1899
1900 ourstatus->kind = TARGET_WAITKIND_EXECD;
1901 ourstatus->value.execd_pathname
1902 = xstrdup (linux_child_pid_to_exec_file (pid));
1903
1904 if (linux_parent_pid)
1905 {
1906 detach_breakpoints (linux_parent_pid);
1907 ptrace (PTRACE_DETACH, linux_parent_pid, 0, 0);
1908
1909 linux_parent_pid = 0;
1910 }
1911
1912 /* At this point, all inserted breakpoints are gone. Doing this
1913 as soon as we detect an exec prevents the badness of deleting
1914 a breakpoint writing the current "shadow contents" to lift
1915 the bp. That shadow is NOT valid after an exec.
1916
1917 Note that we have to do this after the detach_breakpoints
1918 call above, otherwise breakpoints wouldn't be lifted from the
1919 parent on a vfork, because detach_breakpoints would think
1920 that breakpoints are not inserted. */
1921 mark_breakpoints_out ();
1922 return 0;
1923 }
1924
1925 internal_error (__FILE__, __LINE__,
1926 _("unknown ptrace event %d"), event);
1927 }
1928
1929 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
1930 exited. */
1931
1932 static int
1933 wait_lwp (struct lwp_info *lp)
1934 {
1935 pid_t pid;
1936 int status;
1937 int thread_dead = 0;
1938
1939 gdb_assert (!lp->stopped);
1940 gdb_assert (lp->status == 0);
1941
1942 pid = my_waitpid (GET_LWP (lp->ptid), &status, 0);
1943 if (pid == -1 && errno == ECHILD)
1944 {
1945 pid = my_waitpid (GET_LWP (lp->ptid), &status, __WCLONE);
1946 if (pid == -1 && errno == ECHILD)
1947 {
1948 /* The thread has previously exited. We need to delete it
1949 now because, for some vendor 2.4 kernels with NPTL
1950 support backported, there won't be an exit event unless
1951 it is the main thread. 2.6 kernels will report an exit
1952 event for each thread that exits, as expected. */
1953 thread_dead = 1;
1954 if (debug_linux_nat)
1955 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
1956 target_pid_to_str (lp->ptid));
1957 }
1958 }
1959
1960 if (!thread_dead)
1961 {
1962 gdb_assert (pid == GET_LWP (lp->ptid));
1963
1964 if (debug_linux_nat)
1965 {
1966 fprintf_unfiltered (gdb_stdlog,
1967 "WL: waitpid %s received %s\n",
1968 target_pid_to_str (lp->ptid),
1969 status_to_str (status));
1970 }
1971 }
1972
1973 /* Check if the thread has exited. */
1974 if (WIFEXITED (status) || WIFSIGNALED (status))
1975 {
1976 thread_dead = 1;
1977 if (debug_linux_nat)
1978 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
1979 target_pid_to_str (lp->ptid));
1980 }
1981
1982 if (thread_dead)
1983 {
1984 exit_lwp (lp);
1985 return 0;
1986 }
1987
1988 gdb_assert (WIFSTOPPED (status));
1989
1990 /* Handle GNU/Linux's extended waitstatus for trace events. */
1991 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
1992 {
1993 if (debug_linux_nat)
1994 fprintf_unfiltered (gdb_stdlog,
1995 "WL: Handling extended status 0x%06x\n",
1996 status);
1997 if (linux_handle_extended_wait (lp, status, 1))
1998 return wait_lwp (lp);
1999 }
2000
2001 return status;
2002 }
2003
2004 /* Save the most recent siginfo for LP. This is currently only called
2005 for SIGTRAP; some ports use the si_addr field for
2006 target_stopped_data_address. In the future, it may also be used to
2007 restore the siginfo of requeued signals. */
2008
2009 static void
2010 save_siginfo (struct lwp_info *lp)
2011 {
2012 errno = 0;
2013 ptrace (PTRACE_GETSIGINFO, GET_LWP (lp->ptid),
2014 (PTRACE_TYPE_ARG3) 0, &lp->siginfo);
2015
2016 if (errno != 0)
2017 memset (&lp->siginfo, 0, sizeof (lp->siginfo));
2018 }
2019
2020 /* Send a SIGSTOP to LP. */
2021
2022 static int
2023 stop_callback (struct lwp_info *lp, void *data)
2024 {
2025 if (!lp->stopped && !lp->signalled)
2026 {
2027 int ret;
2028
2029 if (debug_linux_nat)
2030 {
2031 fprintf_unfiltered (gdb_stdlog,
2032 "SC: kill %s **<SIGSTOP>**\n",
2033 target_pid_to_str (lp->ptid));
2034 }
2035 errno = 0;
2036 ret = kill_lwp (GET_LWP (lp->ptid), SIGSTOP);
2037 if (debug_linux_nat)
2038 {
2039 fprintf_unfiltered (gdb_stdlog,
2040 "SC: lwp kill %d %s\n",
2041 ret,
2042 errno ? safe_strerror (errno) : "ERRNO-OK");
2043 }
2044
2045 lp->signalled = 1;
2046 gdb_assert (lp->status == 0);
2047 }
2048
2049 return 0;
2050 }
2051
2052 /* Return non-zero if LWP PID has a pending SIGINT. */
2053
2054 static int
2055 linux_nat_has_pending_sigint (int pid)
2056 {
2057 sigset_t pending, blocked, ignored;
2058 int i;
2059
2060 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2061
2062 if (sigismember (&pending, SIGINT)
2063 && !sigismember (&ignored, SIGINT))
2064 return 1;
2065
2066 return 0;
2067 }
2068
2069 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2070
2071 static int
2072 set_ignore_sigint (struct lwp_info *lp, void *data)
2073 {
2074 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2075 flag to consume the next one. */
2076 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2077 && WSTOPSIG (lp->status) == SIGINT)
2078 lp->status = 0;
2079 else
2080 lp->ignore_sigint = 1;
2081
2082 return 0;
2083 }
2084
2085 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2086 This function is called after we know the LWP has stopped; if the LWP
2087 stopped before the expected SIGINT was delivered, then it will never have
2088 arrived. Also, if the signal was delivered to a shared queue and consumed
2089 by a different thread, it will never be delivered to this LWP. */
2090
2091 static void
2092 maybe_clear_ignore_sigint (struct lwp_info *lp)
2093 {
2094 if (!lp->ignore_sigint)
2095 return;
2096
2097 if (!linux_nat_has_pending_sigint (GET_LWP (lp->ptid)))
2098 {
2099 if (debug_linux_nat)
2100 fprintf_unfiltered (gdb_stdlog,
2101 "MCIS: Clearing bogus flag for %s\n",
2102 target_pid_to_str (lp->ptid));
2103 lp->ignore_sigint = 0;
2104 }
2105 }
2106
2107 /* Wait until LP is stopped. */
2108
2109 static int
2110 stop_wait_callback (struct lwp_info *lp, void *data)
2111 {
2112 if (!lp->stopped)
2113 {
2114 int status;
2115
2116 status = wait_lwp (lp);
2117 if (status == 0)
2118 return 0;
2119
2120 if (lp->ignore_sigint && WIFSTOPPED (status)
2121 && WSTOPSIG (status) == SIGINT)
2122 {
2123 lp->ignore_sigint = 0;
2124
2125 errno = 0;
2126 ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
2127 if (debug_linux_nat)
2128 fprintf_unfiltered (gdb_stdlog,
2129 "PTRACE_CONT %s, 0, 0 (%s) (discarding SIGINT)\n",
2130 target_pid_to_str (lp->ptid),
2131 errno ? safe_strerror (errno) : "OK");
2132
2133 return stop_wait_callback (lp, NULL);
2134 }
2135
2136 maybe_clear_ignore_sigint (lp);
2137
2138 if (WSTOPSIG (status) != SIGSTOP)
2139 {
2140 if (WSTOPSIG (status) == SIGTRAP)
2141 {
2142 /* If a LWP other than the LWP that we're reporting an
2143 event for has hit a GDB breakpoint (as opposed to
2144 some random trap signal), then just arrange for it to
2145 hit it again later. We don't keep the SIGTRAP status
2146 and don't forward the SIGTRAP signal to the LWP. We
2147 will handle the current event, eventually we will
2148 resume all LWPs, and this one will get its breakpoint
2149 trap again.
2150
2151 If we do not do this, then we run the risk that the
2152 user will delete or disable the breakpoint, but the
2153 thread will have already tripped on it. */
2154
2155 /* Save the trap's siginfo in case we need it later. */
2156 save_siginfo (lp);
2157
2158 /* Now resume this LWP and get the SIGSTOP event. */
2159 errno = 0;
2160 ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
2161 if (debug_linux_nat)
2162 {
2163 fprintf_unfiltered (gdb_stdlog,
2164 "PTRACE_CONT %s, 0, 0 (%s)\n",
2165 target_pid_to_str (lp->ptid),
2166 errno ? safe_strerror (errno) : "OK");
2167
2168 fprintf_unfiltered (gdb_stdlog,
2169 "SWC: Candidate SIGTRAP event in %s\n",
2170 target_pid_to_str (lp->ptid));
2171 }
2172 /* Hold this event/waitstatus while we check to see if
2173 there are any more (we still want to get that SIGSTOP). */
2174 stop_wait_callback (lp, NULL);
2175
2176 /* Hold the SIGTRAP for handling by linux_nat_wait. If
2177 there's another event, throw it back into the
2178 queue. */
2179 if (lp->status)
2180 {
2181 if (debug_linux_nat)
2182 fprintf_unfiltered (gdb_stdlog,
2183 "SWC: kill %s, %s\n",
2184 target_pid_to_str (lp->ptid),
2185 status_to_str ((int) status));
2186 kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (lp->status));
2187 }
2188
2189 /* Save the sigtrap event. */
2190 lp->status = status;
2191 return 0;
2192 }
2193 else
2194 {
2195 /* The thread was stopped with a signal other than
2196 SIGSTOP, and didn't accidentally trip a breakpoint. */
2197
2198 if (debug_linux_nat)
2199 {
2200 fprintf_unfiltered (gdb_stdlog,
2201 "SWC: Pending event %s in %s\n",
2202 status_to_str ((int) status),
2203 target_pid_to_str (lp->ptid));
2204 }
2205 /* Now resume this LWP and get the SIGSTOP event. */
2206 errno = 0;
2207 ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
2208 if (debug_linux_nat)
2209 fprintf_unfiltered (gdb_stdlog,
2210 "SWC: PTRACE_CONT %s, 0, 0 (%s)\n",
2211 target_pid_to_str (lp->ptid),
2212 errno ? safe_strerror (errno) : "OK");
2213
2214 /* Hold this event/waitstatus while we check to see if
2215 there are any more (we still want to get that SIGSTOP). */
2216 stop_wait_callback (lp, NULL);
2217
2218 /* If the lp->status field is still empty, use it to
2219 hold this event. If not, then this event must be
2220 returned to the event queue of the LWP. */
2221 if (lp->status)
2222 {
2223 if (debug_linux_nat)
2224 {
2225 fprintf_unfiltered (gdb_stdlog,
2226 "SWC: kill %s, %s\n",
2227 target_pid_to_str (lp->ptid),
2228 status_to_str ((int) status));
2229 }
2230 kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (status));
2231 }
2232 else
2233 lp->status = status;
2234 return 0;
2235 }
2236 }
2237 else
2238 {
2239 /* We caught the SIGSTOP that we intended to catch, so
2240 there's no SIGSTOP pending. */
2241 lp->stopped = 1;
2242 lp->signalled = 0;
2243 }
2244 }
2245
2246 return 0;
2247 }
2248
2249 /* Return non-zero if LP has a wait status pending. */
2250
2251 static int
2252 status_callback (struct lwp_info *lp, void *data)
2253 {
2254 /* Only report a pending wait status if we pretend that this has
2255 indeed been resumed. */
2256 /* We check for lp->waitstatus in addition to lp->status, because we
2257 can have pending process exits recorded in lp->waitstatus, and
2258 W_EXITCODE(0,0) == 0. */
2259 return ((lp->status != 0
2260 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2261 && lp->resumed);
2262 }
2263
2264 /* Return non-zero if LP isn't stopped. */
2265
2266 static int
2267 running_callback (struct lwp_info *lp, void *data)
2268 {
2269 return (lp->stopped == 0 || (lp->status != 0 && lp->resumed));
2270 }
2271
2272 /* Count the LWP's that have had events. */
2273
2274 static int
2275 count_events_callback (struct lwp_info *lp, void *data)
2276 {
2277 int *count = data;
2278
2279 gdb_assert (count != NULL);
2280
2281 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2282 if (lp->status != 0 && lp->resumed
2283 && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP)
2284 (*count)++;
2285
2286 return 0;
2287 }
2288
2289 /* Select the LWP (if any) that is currently being single-stepped. */
2290
2291 static int
2292 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2293 {
2294 if (lp->step && lp->status != 0)
2295 return 1;
2296 else
2297 return 0;
2298 }
2299
2300 /* Select the Nth LWP that has had a SIGTRAP event. */
2301
2302 static int
2303 select_event_lwp_callback (struct lwp_info *lp, void *data)
2304 {
2305 int *selector = data;
2306
2307 gdb_assert (selector != NULL);
2308
2309 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2310 if (lp->status != 0 && lp->resumed
2311 && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP)
2312 if ((*selector)-- == 0)
2313 return 1;
2314
2315 return 0;
2316 }
2317
2318 static int
2319 cancel_breakpoint (struct lwp_info *lp)
2320 {
2321 /* Arrange for a breakpoint to be hit again later. We don't keep
2322 the SIGTRAP status and don't forward the SIGTRAP signal to the
2323 LWP. We will handle the current event, eventually we will resume
2324 this LWP, and this breakpoint will trap again.
2325
2326 If we do not do this, then we run the risk that the user will
2327 delete or disable the breakpoint, but the LWP will have already
2328 tripped on it. */
2329
2330 struct regcache *regcache = get_thread_regcache (lp->ptid);
2331 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2332 CORE_ADDR pc;
2333
2334 pc = regcache_read_pc (regcache) - gdbarch_decr_pc_after_break (gdbarch);
2335 if (breakpoint_inserted_here_p (pc))
2336 {
2337 if (debug_linux_nat)
2338 fprintf_unfiltered (gdb_stdlog,
2339 "CB: Push back breakpoint for %s\n",
2340 target_pid_to_str (lp->ptid));
2341
2342 /* Back up the PC if necessary. */
2343 if (gdbarch_decr_pc_after_break (gdbarch))
2344 regcache_write_pc (regcache, pc);
2345
2346 return 1;
2347 }
2348 return 0;
2349 }
2350
2351 static int
2352 cancel_breakpoints_callback (struct lwp_info *lp, void *data)
2353 {
2354 struct lwp_info *event_lp = data;
2355
2356 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2357 if (lp == event_lp)
2358 return 0;
2359
2360 /* If a LWP other than the LWP that we're reporting an event for has
2361 hit a GDB breakpoint (as opposed to some random trap signal),
2362 then just arrange for it to hit it again later. We don't keep
2363 the SIGTRAP status and don't forward the SIGTRAP signal to the
2364 LWP. We will handle the current event, eventually we will resume
2365 all LWPs, and this one will get its breakpoint trap again.
2366
2367 If we do not do this, then we run the risk that the user will
2368 delete or disable the breakpoint, but the LWP will have already
2369 tripped on it. */
2370
2371 if (lp->status != 0
2372 && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP
2373 && cancel_breakpoint (lp))
2374 /* Throw away the SIGTRAP. */
2375 lp->status = 0;
2376
2377 return 0;
2378 }
2379
2380 /* Select one LWP out of those that have events pending. */
2381
2382 static void
2383 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2384 {
2385 int num_events = 0;
2386 int random_selector;
2387 struct lwp_info *event_lp;
2388
2389 /* Record the wait status for the original LWP. */
2390 (*orig_lp)->status = *status;
2391
2392 /* Give preference to any LWP that is being single-stepped. */
2393 event_lp = iterate_over_lwps (filter,
2394 select_singlestep_lwp_callback, NULL);
2395 if (event_lp != NULL)
2396 {
2397 if (debug_linux_nat)
2398 fprintf_unfiltered (gdb_stdlog,
2399 "SEL: Select single-step %s\n",
2400 target_pid_to_str (event_lp->ptid));
2401 }
2402 else
2403 {
2404 /* No single-stepping LWP. Select one at random, out of those
2405 which have had SIGTRAP events. */
2406
2407 /* First see how many SIGTRAP events we have. */
2408 iterate_over_lwps (filter, count_events_callback, &num_events);
2409
2410 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2411 random_selector = (int)
2412 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2413
2414 if (debug_linux_nat && num_events > 1)
2415 fprintf_unfiltered (gdb_stdlog,
2416 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2417 num_events, random_selector);
2418
2419 event_lp = iterate_over_lwps (filter,
2420 select_event_lwp_callback,
2421 &random_selector);
2422 }
2423
2424 if (event_lp != NULL)
2425 {
2426 /* Switch the event LWP. */
2427 *orig_lp = event_lp;
2428 *status = event_lp->status;
2429 }
2430
2431 /* Flush the wait status for the event LWP. */
2432 (*orig_lp)->status = 0;
2433 }
2434
2435 /* Return non-zero if LP has been resumed. */
2436
2437 static int
2438 resumed_callback (struct lwp_info *lp, void *data)
2439 {
2440 return lp->resumed;
2441 }
2442
2443 /* Stop an active thread, verify it still exists, then resume it. */
2444
2445 static int
2446 stop_and_resume_callback (struct lwp_info *lp, void *data)
2447 {
2448 struct lwp_info *ptr;
2449
2450 if (!lp->stopped && !lp->signalled)
2451 {
2452 stop_callback (lp, NULL);
2453 stop_wait_callback (lp, NULL);
2454 /* Resume if the lwp still exists. */
2455 for (ptr = lwp_list; ptr; ptr = ptr->next)
2456 if (lp == ptr)
2457 {
2458 resume_callback (lp, NULL);
2459 resume_set_callback (lp, NULL);
2460 }
2461 }
2462 return 0;
2463 }
2464
2465 /* Check if we should go on and pass this event to common code.
2466 Return the affected lwp if we are, or NULL otherwise. */
2467 static struct lwp_info *
2468 linux_nat_filter_event (int lwpid, int status, int options)
2469 {
2470 struct lwp_info *lp;
2471
2472 lp = find_lwp_pid (pid_to_ptid (lwpid));
2473
2474 /* Check for stop events reported by a process we didn't already
2475 know about - anything not already in our LWP list.
2476
2477 If we're expecting to receive stopped processes after
2478 fork, vfork, and clone events, then we'll just add the
2479 new one to our list and go back to waiting for the event
2480 to be reported - the stopped process might be returned
2481 from waitpid before or after the event is. */
2482 if (WIFSTOPPED (status) && !lp)
2483 {
2484 linux_record_stopped_pid (lwpid, status);
2485 return NULL;
2486 }
2487
2488 /* Make sure we don't report an event for the exit of an LWP not in
2489 our list, i.e. not part of the current process. This can happen
2490 if we detach from a program we original forked and then it
2491 exits. */
2492 if (!WIFSTOPPED (status) && !lp)
2493 return NULL;
2494
2495 /* NOTE drow/2003-06-17: This code seems to be meant for debugging
2496 CLONE_PTRACE processes which do not use the thread library -
2497 otherwise we wouldn't find the new LWP this way. That doesn't
2498 currently work, and the following code is currently unreachable
2499 due to the two blocks above. If it's fixed some day, this code
2500 should be broken out into a function so that we can also pick up
2501 LWPs from the new interface. */
2502 if (!lp)
2503 {
2504 lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid)));
2505 if (options & __WCLONE)
2506 lp->cloned = 1;
2507
2508 gdb_assert (WIFSTOPPED (status)
2509 && WSTOPSIG (status) == SIGSTOP);
2510 lp->signalled = 1;
2511
2512 if (!in_thread_list (inferior_ptid))
2513 {
2514 inferior_ptid = BUILD_LWP (GET_PID (inferior_ptid),
2515 GET_PID (inferior_ptid));
2516 add_thread (inferior_ptid);
2517 }
2518
2519 add_thread (lp->ptid);
2520 }
2521
2522 /* Save the trap's siginfo in case we need it later. */
2523 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP)
2524 save_siginfo (lp);
2525
2526 /* Handle GNU/Linux's extended waitstatus for trace events. */
2527 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2528 {
2529 if (debug_linux_nat)
2530 fprintf_unfiltered (gdb_stdlog,
2531 "LLW: Handling extended status 0x%06x\n",
2532 status);
2533 if (linux_handle_extended_wait (lp, status, 0))
2534 return NULL;
2535 }
2536
2537 /* Check if the thread has exited. */
2538 if ((WIFEXITED (status) || WIFSIGNALED (status))
2539 && num_lwps (GET_PID (lp->ptid)) > 1)
2540 {
2541 /* If this is the main thread, we must stop all threads and verify
2542 if they are still alive. This is because in the nptl thread model
2543 on Linux 2.4, there is no signal issued for exiting LWPs
2544 other than the main thread. We only get the main thread exit
2545 signal once all child threads have already exited. If we
2546 stop all the threads and use the stop_wait_callback to check
2547 if they have exited we can determine whether this signal
2548 should be ignored or whether it means the end of the debugged
2549 application, regardless of which threading model is being
2550 used. */
2551 if (GET_PID (lp->ptid) == GET_LWP (lp->ptid))
2552 {
2553 lp->stopped = 1;
2554 iterate_over_lwps (pid_to_ptid (GET_PID (lp->ptid)),
2555 stop_and_resume_callback, NULL);
2556 }
2557
2558 if (debug_linux_nat)
2559 fprintf_unfiltered (gdb_stdlog,
2560 "LLW: %s exited.\n",
2561 target_pid_to_str (lp->ptid));
2562
2563 if (num_lwps (GET_PID (lp->ptid)) > 1)
2564 {
2565 /* If there is at least one more LWP, then the exit signal
2566 was not the end of the debugged application and should be
2567 ignored. */
2568 exit_lwp (lp);
2569 return NULL;
2570 }
2571 }
2572
2573 /* Check if the current LWP has previously exited. In the nptl
2574 thread model, LWPs other than the main thread do not issue
2575 signals when they exit so we must check whenever the thread has
2576 stopped. A similar check is made in stop_wait_callback(). */
2577 if (num_lwps (GET_PID (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
2578 {
2579 ptid_t ptid = pid_to_ptid (GET_PID (lp->ptid));
2580
2581 if (debug_linux_nat)
2582 fprintf_unfiltered (gdb_stdlog,
2583 "LLW: %s exited.\n",
2584 target_pid_to_str (lp->ptid));
2585
2586 exit_lwp (lp);
2587
2588 /* Make sure there is at least one thread running. */
2589 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
2590
2591 /* Discard the event. */
2592 return NULL;
2593 }
2594
2595 /* Make sure we don't report a SIGSTOP that we sent ourselves in
2596 an attempt to stop an LWP. */
2597 if (lp->signalled
2598 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
2599 {
2600 if (debug_linux_nat)
2601 fprintf_unfiltered (gdb_stdlog,
2602 "LLW: Delayed SIGSTOP caught for %s.\n",
2603 target_pid_to_str (lp->ptid));
2604
2605 /* This is a delayed SIGSTOP. */
2606 lp->signalled = 0;
2607
2608 registers_changed ();
2609
2610 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
2611 lp->step, TARGET_SIGNAL_0);
2612 if (debug_linux_nat)
2613 fprintf_unfiltered (gdb_stdlog,
2614 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
2615 lp->step ?
2616 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2617 target_pid_to_str (lp->ptid));
2618
2619 lp->stopped = 0;
2620 gdb_assert (lp->resumed);
2621
2622 /* Discard the event. */
2623 return NULL;
2624 }
2625
2626 /* Make sure we don't report a SIGINT that we have already displayed
2627 for another thread. */
2628 if (lp->ignore_sigint
2629 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
2630 {
2631 if (debug_linux_nat)
2632 fprintf_unfiltered (gdb_stdlog,
2633 "LLW: Delayed SIGINT caught for %s.\n",
2634 target_pid_to_str (lp->ptid));
2635
2636 /* This is a delayed SIGINT. */
2637 lp->ignore_sigint = 0;
2638
2639 registers_changed ();
2640 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
2641 lp->step, TARGET_SIGNAL_0);
2642 if (debug_linux_nat)
2643 fprintf_unfiltered (gdb_stdlog,
2644 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
2645 lp->step ?
2646 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2647 target_pid_to_str (lp->ptid));
2648
2649 lp->stopped = 0;
2650 gdb_assert (lp->resumed);
2651
2652 /* Discard the event. */
2653 return NULL;
2654 }
2655
2656 /* An interesting event. */
2657 gdb_assert (lp);
2658 return lp;
2659 }
2660
2661 static ptid_t
2662 linux_nat_wait_1 (struct target_ops *ops,
2663 ptid_t ptid, struct target_waitstatus *ourstatus,
2664 int target_options)
2665 {
2666 static sigset_t prev_mask;
2667 struct lwp_info *lp = NULL;
2668 int options = 0;
2669 int status = 0;
2670 pid_t pid;
2671
2672 if (debug_linux_nat_async)
2673 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
2674
2675 /* The first time we get here after starting a new inferior, we may
2676 not have added it to the LWP list yet - this is the earliest
2677 moment at which we know its PID. */
2678 if (ptid_is_pid (inferior_ptid))
2679 {
2680 /* Upgrade the main thread's ptid. */
2681 thread_change_ptid (inferior_ptid,
2682 BUILD_LWP (GET_PID (inferior_ptid),
2683 GET_PID (inferior_ptid)));
2684
2685 lp = add_lwp (inferior_ptid);
2686 lp->resumed = 1;
2687 }
2688
2689 /* Make sure SIGCHLD is blocked. */
2690 block_child_signals (&prev_mask);
2691
2692 if (ptid_equal (ptid, minus_one_ptid))
2693 pid = -1;
2694 else if (ptid_is_pid (ptid))
2695 /* A request to wait for a specific tgid. This is not possible
2696 with waitpid, so instead, we wait for any child, and leave
2697 children we're not interested in right now with a pending
2698 status to report later. */
2699 pid = -1;
2700 else
2701 pid = GET_LWP (ptid);
2702
2703 retry:
2704 lp = NULL;
2705 status = 0;
2706
2707 /* Make sure there is at least one LWP that has been resumed. */
2708 gdb_assert (iterate_over_lwps (ptid, resumed_callback, NULL));
2709
2710 /* First check if there is a LWP with a wait status pending. */
2711 if (pid == -1)
2712 {
2713 /* Any LWP that's been resumed will do. */
2714 lp = iterate_over_lwps (ptid, status_callback, NULL);
2715 if (lp)
2716 {
2717 status = lp->status;
2718 lp->status = 0;
2719
2720 if (debug_linux_nat && status)
2721 fprintf_unfiltered (gdb_stdlog,
2722 "LLW: Using pending wait status %s for %s.\n",
2723 status_to_str (status),
2724 target_pid_to_str (lp->ptid));
2725 }
2726
2727 /* But if we don't find one, we'll have to wait, and check both
2728 cloned and uncloned processes. We start with the cloned
2729 processes. */
2730 options = __WCLONE | WNOHANG;
2731 }
2732 else if (is_lwp (ptid))
2733 {
2734 if (debug_linux_nat)
2735 fprintf_unfiltered (gdb_stdlog,
2736 "LLW: Waiting for specific LWP %s.\n",
2737 target_pid_to_str (ptid));
2738
2739 /* We have a specific LWP to check. */
2740 lp = find_lwp_pid (ptid);
2741 gdb_assert (lp);
2742 status = lp->status;
2743 lp->status = 0;
2744
2745 if (debug_linux_nat && status)
2746 fprintf_unfiltered (gdb_stdlog,
2747 "LLW: Using pending wait status %s for %s.\n",
2748 status_to_str (status),
2749 target_pid_to_str (lp->ptid));
2750
2751 /* If we have to wait, take into account whether PID is a cloned
2752 process or not. And we have to convert it to something that
2753 the layer beneath us can understand. */
2754 options = lp->cloned ? __WCLONE : 0;
2755 pid = GET_LWP (ptid);
2756
2757 /* We check for lp->waitstatus in addition to lp->status,
2758 because we can have pending process exits recorded in
2759 lp->status and W_EXITCODE(0,0) == 0. We should probably have
2760 an additional lp->status_p flag. */
2761 if (status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
2762 lp = NULL;
2763 }
2764
2765 if (lp && lp->signalled)
2766 {
2767 /* A pending SIGSTOP may interfere with the normal stream of
2768 events. In a typical case where interference is a problem,
2769 we have a SIGSTOP signal pending for LWP A while
2770 single-stepping it, encounter an event in LWP B, and take the
2771 pending SIGSTOP while trying to stop LWP A. After processing
2772 the event in LWP B, LWP A is continued, and we'll never see
2773 the SIGTRAP associated with the last time we were
2774 single-stepping LWP A. */
2775
2776 /* Resume the thread. It should halt immediately returning the
2777 pending SIGSTOP. */
2778 registers_changed ();
2779 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
2780 lp->step, TARGET_SIGNAL_0);
2781 if (debug_linux_nat)
2782 fprintf_unfiltered (gdb_stdlog,
2783 "LLW: %s %s, 0, 0 (expect SIGSTOP)\n",
2784 lp->step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2785 target_pid_to_str (lp->ptid));
2786 lp->stopped = 0;
2787 gdb_assert (lp->resumed);
2788
2789 /* This should catch the pending SIGSTOP. */
2790 stop_wait_callback (lp, NULL);
2791 }
2792
2793 if (!target_can_async_p ())
2794 {
2795 /* Causes SIGINT to be passed on to the attached process. */
2796 set_sigint_trap ();
2797 }
2798
2799 /* Translate generic target_wait options into waitpid options. */
2800 if (target_options & TARGET_WNOHANG)
2801 options |= WNOHANG;
2802
2803 while (lp == NULL)
2804 {
2805 pid_t lwpid;
2806
2807 lwpid = my_waitpid (pid, &status, options);
2808
2809 if (lwpid > 0)
2810 {
2811 gdb_assert (pid == -1 || lwpid == pid);
2812
2813 if (debug_linux_nat)
2814 {
2815 fprintf_unfiltered (gdb_stdlog,
2816 "LLW: waitpid %ld received %s\n",
2817 (long) lwpid, status_to_str (status));
2818 }
2819
2820 lp = linux_nat_filter_event (lwpid, status, options);
2821
2822 if (lp
2823 && ptid_is_pid (ptid)
2824 && ptid_get_pid (lp->ptid) != ptid_get_pid (ptid))
2825 {
2826 if (debug_linux_nat)
2827 fprintf (stderr, "LWP %ld got an event %06x, leaving pending.\n",
2828 ptid_get_lwp (lp->ptid), status);
2829
2830 if (WIFSTOPPED (status))
2831 {
2832 if (WSTOPSIG (status) != SIGSTOP)
2833 {
2834 lp->status = status;
2835
2836 stop_callback (lp, NULL);
2837
2838 /* Resume in order to collect the sigstop. */
2839 ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
2840
2841 stop_wait_callback (lp, NULL);
2842 }
2843 else
2844 {
2845 lp->stopped = 1;
2846 lp->signalled = 0;
2847 }
2848 }
2849 else if (WIFEXITED (status) || WIFSIGNALED (status))
2850 {
2851 if (debug_linux_nat)
2852 fprintf (stderr, "Process %ld exited while stopping LWPs\n",
2853 ptid_get_lwp (lp->ptid));
2854
2855 /* This was the last lwp in the process. Since
2856 events are serialized to GDB core, and we can't
2857 report this one right now, but GDB core and the
2858 other target layers will want to be notified
2859 about the exit code/signal, leave the status
2860 pending for the next time we're able to report
2861 it. */
2862 lp->status = status;
2863
2864 /* Prevent trying to stop this thread again. We'll
2865 never try to resume it because it has a pending
2866 status. */
2867 lp->stopped = 1;
2868
2869 /* Dead LWP's aren't expected to reported a pending
2870 sigstop. */
2871 lp->signalled = 0;
2872
2873 /* Store the pending event in the waitstatus as
2874 well, because W_EXITCODE(0,0) == 0. */
2875 store_waitstatus (&lp->waitstatus, status);
2876 }
2877
2878 /* Keep looking. */
2879 lp = NULL;
2880 continue;
2881 }
2882
2883 if (lp)
2884 break;
2885 else
2886 {
2887 if (pid == -1)
2888 {
2889 /* waitpid did return something. Restart over. */
2890 options |= __WCLONE;
2891 }
2892 continue;
2893 }
2894 }
2895
2896 if (pid == -1)
2897 {
2898 /* Alternate between checking cloned and uncloned processes. */
2899 options ^= __WCLONE;
2900
2901 /* And every time we have checked both:
2902 In async mode, return to event loop;
2903 In sync mode, suspend waiting for a SIGCHLD signal. */
2904 if (options & __WCLONE)
2905 {
2906 if (target_options & TARGET_WNOHANG)
2907 {
2908 /* No interesting event. */
2909 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2910
2911 if (debug_linux_nat_async)
2912 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
2913
2914 restore_child_signals_mask (&prev_mask);
2915 return minus_one_ptid;
2916 }
2917
2918 sigsuspend (&suspend_mask);
2919 }
2920 }
2921
2922 /* We shouldn't end up here unless we want to try again. */
2923 gdb_assert (lp == NULL);
2924 }
2925
2926 if (!target_can_async_p ())
2927 clear_sigint_trap ();
2928
2929 gdb_assert (lp);
2930
2931 /* Don't report signals that GDB isn't interested in, such as
2932 signals that are neither printed nor stopped upon. Stopping all
2933 threads can be a bit time-consuming so if we want decent
2934 performance with heavily multi-threaded programs, especially when
2935 they're using a high frequency timer, we'd better avoid it if we
2936 can. */
2937
2938 if (WIFSTOPPED (status))
2939 {
2940 int signo = target_signal_from_host (WSTOPSIG (status));
2941 struct inferior *inf;
2942
2943 inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2944 gdb_assert (inf);
2945
2946 /* Defer to common code if we get a signal while
2947 single-stepping, since that may need special care, e.g. to
2948 skip the signal handler, or, if we're gaining control of the
2949 inferior. */
2950 if (!lp->step
2951 && inf->stop_soon == NO_STOP_QUIETLY
2952 && signal_stop_state (signo) == 0
2953 && signal_print_state (signo) == 0
2954 && signal_pass_state (signo) == 1)
2955 {
2956 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
2957 here? It is not clear we should. GDB may not expect
2958 other threads to run. On the other hand, not resuming
2959 newly attached threads may cause an unwanted delay in
2960 getting them running. */
2961 registers_changed ();
2962 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
2963 lp->step, signo);
2964 if (debug_linux_nat)
2965 fprintf_unfiltered (gdb_stdlog,
2966 "LLW: %s %s, %s (preempt 'handle')\n",
2967 lp->step ?
2968 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2969 target_pid_to_str (lp->ptid),
2970 signo ? strsignal (signo) : "0");
2971 lp->stopped = 0;
2972 goto retry;
2973 }
2974
2975 if (!non_stop)
2976 {
2977 /* Only do the below in all-stop, as we currently use SIGINT
2978 to implement target_stop (see linux_nat_stop) in
2979 non-stop. */
2980 if (signo == TARGET_SIGNAL_INT && signal_pass_state (signo) == 0)
2981 {
2982 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
2983 forwarded to the entire process group, that is, all LWPs
2984 will receive it - unless they're using CLONE_THREAD to
2985 share signals. Since we only want to report it once, we
2986 mark it as ignored for all LWPs except this one. */
2987 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)),
2988 set_ignore_sigint, NULL);
2989 lp->ignore_sigint = 0;
2990 }
2991 else
2992 maybe_clear_ignore_sigint (lp);
2993 }
2994 }
2995
2996 /* This LWP is stopped now. */
2997 lp->stopped = 1;
2998
2999 if (debug_linux_nat)
3000 fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
3001 status_to_str (status), target_pid_to_str (lp->ptid));
3002
3003 if (!non_stop)
3004 {
3005 /* Now stop all other LWP's ... */
3006 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3007
3008 /* ... and wait until all of them have reported back that
3009 they're no longer running. */
3010 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3011
3012 /* If we're not waiting for a specific LWP, choose an event LWP
3013 from among those that have had events. Giving equal priority
3014 to all LWPs that have had events helps prevent
3015 starvation. */
3016 if (pid == -1)
3017 select_event_lwp (ptid, &lp, &status);
3018 }
3019
3020 /* Now that we've selected our final event LWP, cancel any
3021 breakpoints in other LWPs that have hit a GDB breakpoint. See
3022 the comment in cancel_breakpoints_callback to find out why. */
3023 iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp);
3024
3025 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP)
3026 {
3027 if (debug_linux_nat)
3028 fprintf_unfiltered (gdb_stdlog,
3029 "LLW: trap ptid is %s.\n",
3030 target_pid_to_str (lp->ptid));
3031 }
3032
3033 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3034 {
3035 *ourstatus = lp->waitstatus;
3036 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3037 }
3038 else
3039 store_waitstatus (ourstatus, status);
3040
3041 if (debug_linux_nat_async)
3042 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3043
3044 restore_child_signals_mask (&prev_mask);
3045 return lp->ptid;
3046 }
3047
3048 static ptid_t
3049 linux_nat_wait (struct target_ops *ops,
3050 ptid_t ptid, struct target_waitstatus *ourstatus,
3051 int target_options)
3052 {
3053 ptid_t event_ptid;
3054
3055 if (debug_linux_nat)
3056 fprintf_unfiltered (gdb_stdlog, "linux_nat_wait: [%s]\n", target_pid_to_str (ptid));
3057
3058 /* Flush the async file first. */
3059 if (target_can_async_p ())
3060 async_file_flush ();
3061
3062 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3063
3064 /* If we requested any event, and something came out, assume there
3065 may be more. If we requested a specific lwp or process, also
3066 assume there may be more. */
3067 if (target_can_async_p ()
3068 && (ourstatus->kind != TARGET_WAITKIND_IGNORE
3069 || !ptid_equal (ptid, minus_one_ptid)))
3070 async_file_mark ();
3071
3072 /* Get ready for the next event. */
3073 if (target_can_async_p ())
3074 target_async (inferior_event_handler, 0);
3075
3076 return event_ptid;
3077 }
3078
3079 static int
3080 kill_callback (struct lwp_info *lp, void *data)
3081 {
3082 errno = 0;
3083 ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0);
3084 if (debug_linux_nat)
3085 fprintf_unfiltered (gdb_stdlog,
3086 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3087 target_pid_to_str (lp->ptid),
3088 errno ? safe_strerror (errno) : "OK");
3089
3090 return 0;
3091 }
3092
3093 static int
3094 kill_wait_callback (struct lwp_info *lp, void *data)
3095 {
3096 pid_t pid;
3097
3098 /* We must make sure that there are no pending events (delayed
3099 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3100 program doesn't interfere with any following debugging session. */
3101
3102 /* For cloned processes we must check both with __WCLONE and
3103 without, since the exit status of a cloned process isn't reported
3104 with __WCLONE. */
3105 if (lp->cloned)
3106 {
3107 do
3108 {
3109 pid = my_waitpid (GET_LWP (lp->ptid), NULL, __WCLONE);
3110 if (pid != (pid_t) -1)
3111 {
3112 if (debug_linux_nat)
3113 fprintf_unfiltered (gdb_stdlog,
3114 "KWC: wait %s received unknown.\n",
3115 target_pid_to_str (lp->ptid));
3116 /* The Linux kernel sometimes fails to kill a thread
3117 completely after PTRACE_KILL; that goes from the stop
3118 point in do_fork out to the one in
3119 get_signal_to_deliever and waits again. So kill it
3120 again. */
3121 kill_callback (lp, NULL);
3122 }
3123 }
3124 while (pid == GET_LWP (lp->ptid));
3125
3126 gdb_assert (pid == -1 && errno == ECHILD);
3127 }
3128
3129 do
3130 {
3131 pid = my_waitpid (GET_LWP (lp->ptid), NULL, 0);
3132 if (pid != (pid_t) -1)
3133 {
3134 if (debug_linux_nat)
3135 fprintf_unfiltered (gdb_stdlog,
3136 "KWC: wait %s received unk.\n",
3137 target_pid_to_str (lp->ptid));
3138 /* See the call to kill_callback above. */
3139 kill_callback (lp, NULL);
3140 }
3141 }
3142 while (pid == GET_LWP (lp->ptid));
3143
3144 gdb_assert (pid == -1 && errno == ECHILD);
3145 return 0;
3146 }
3147
3148 static void
3149 linux_nat_kill (struct target_ops *ops)
3150 {
3151 struct target_waitstatus last;
3152 ptid_t last_ptid;
3153 int status;
3154
3155 /* If we're stopped while forking and we haven't followed yet,
3156 kill the other task. We need to do this first because the
3157 parent will be sleeping if this is a vfork. */
3158
3159 get_last_target_status (&last_ptid, &last);
3160
3161 if (last.kind == TARGET_WAITKIND_FORKED
3162 || last.kind == TARGET_WAITKIND_VFORKED)
3163 {
3164 ptrace (PT_KILL, PIDGET (last.value.related_pid), 0, 0);
3165 wait (&status);
3166 }
3167
3168 if (forks_exist_p ())
3169 linux_fork_killall ();
3170 else
3171 {
3172 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3173 /* Stop all threads before killing them, since ptrace requires
3174 that the thread is stopped to sucessfully PTRACE_KILL. */
3175 iterate_over_lwps (ptid, stop_callback, NULL);
3176 /* ... and wait until all of them have reported back that
3177 they're no longer running. */
3178 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3179
3180 /* Kill all LWP's ... */
3181 iterate_over_lwps (ptid, kill_callback, NULL);
3182
3183 /* ... and wait until we've flushed all events. */
3184 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3185 }
3186
3187 target_mourn_inferior ();
3188 }
3189
3190 static void
3191 linux_nat_mourn_inferior (struct target_ops *ops)
3192 {
3193 purge_lwp_list (ptid_get_pid (inferior_ptid));
3194
3195 if (! forks_exist_p ())
3196 /* Normal case, no other forks available. */
3197 linux_ops->to_mourn_inferior (ops);
3198 else
3199 /* Multi-fork case. The current inferior_ptid has exited, but
3200 there are other viable forks to debug. Delete the exiting
3201 one and context-switch to the first available. */
3202 linux_fork_mourn_inferior ();
3203 }
3204
3205 /* Convert a native/host siginfo object, into/from the siginfo in the
3206 layout of the inferiors' architecture. */
3207
3208 static void
3209 siginfo_fixup (struct siginfo *siginfo, gdb_byte *inf_siginfo, int direction)
3210 {
3211 int done = 0;
3212
3213 if (linux_nat_siginfo_fixup != NULL)
3214 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3215
3216 /* If there was no callback, or the callback didn't do anything,
3217 then just do a straight memcpy. */
3218 if (!done)
3219 {
3220 if (direction == 1)
3221 memcpy (siginfo, inf_siginfo, sizeof (struct siginfo));
3222 else
3223 memcpy (inf_siginfo, siginfo, sizeof (struct siginfo));
3224 }
3225 }
3226
3227 static LONGEST
3228 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3229 const char *annex, gdb_byte *readbuf,
3230 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
3231 {
3232 int pid;
3233 struct siginfo siginfo;
3234 gdb_byte inf_siginfo[sizeof (struct siginfo)];
3235
3236 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3237 gdb_assert (readbuf || writebuf);
3238
3239 pid = GET_LWP (inferior_ptid);
3240 if (pid == 0)
3241 pid = GET_PID (inferior_ptid);
3242
3243 if (offset > sizeof (siginfo))
3244 return -1;
3245
3246 errno = 0;
3247 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3248 if (errno != 0)
3249 return -1;
3250
3251 /* When GDB is built as a 64-bit application, ptrace writes into
3252 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3253 inferior with a 64-bit GDB should look the same as debugging it
3254 with a 32-bit GDB, we need to convert it. GDB core always sees
3255 the converted layout, so any read/write will have to be done
3256 post-conversion. */
3257 siginfo_fixup (&siginfo, inf_siginfo, 0);
3258
3259 if (offset + len > sizeof (siginfo))
3260 len = sizeof (siginfo) - offset;
3261
3262 if (readbuf != NULL)
3263 memcpy (readbuf, inf_siginfo + offset, len);
3264 else
3265 {
3266 memcpy (inf_siginfo + offset, writebuf, len);
3267
3268 /* Convert back to ptrace layout before flushing it out. */
3269 siginfo_fixup (&siginfo, inf_siginfo, 1);
3270
3271 errno = 0;
3272 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3273 if (errno != 0)
3274 return -1;
3275 }
3276
3277 return len;
3278 }
3279
3280 static LONGEST
3281 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3282 const char *annex, gdb_byte *readbuf,
3283 const gdb_byte *writebuf,
3284 ULONGEST offset, LONGEST len)
3285 {
3286 struct cleanup *old_chain;
3287 LONGEST xfer;
3288
3289 if (object == TARGET_OBJECT_SIGNAL_INFO)
3290 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3291 offset, len);
3292
3293 /* The target is connected but no live inferior is selected. Pass
3294 this request down to a lower stratum (e.g., the executable
3295 file). */
3296 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3297 return 0;
3298
3299 old_chain = save_inferior_ptid ();
3300
3301 if (is_lwp (inferior_ptid))
3302 inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid));
3303
3304 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3305 offset, len);
3306
3307 do_cleanups (old_chain);
3308 return xfer;
3309 }
3310
3311 static int
3312 linux_thread_alive (ptid_t ptid)
3313 {
3314 int err;
3315
3316 gdb_assert (is_lwp (ptid));
3317
3318 /* Send signal 0 instead of anything ptrace, because ptracing a
3319 running thread errors out claiming that the thread doesn't
3320 exist. */
3321 err = kill_lwp (GET_LWP (ptid), 0);
3322
3323 if (debug_linux_nat)
3324 fprintf_unfiltered (gdb_stdlog,
3325 "LLTA: KILL(SIG0) %s (%s)\n",
3326 target_pid_to_str (ptid),
3327 err ? safe_strerror (err) : "OK");
3328
3329 if (err != 0)
3330 return 0;
3331
3332 return 1;
3333 }
3334
3335 static int
3336 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3337 {
3338 return linux_thread_alive (ptid);
3339 }
3340
3341 static char *
3342 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3343 {
3344 static char buf[64];
3345
3346 if (is_lwp (ptid)
3347 && (GET_PID (ptid) != GET_LWP (ptid)
3348 || num_lwps (GET_PID (ptid)) > 1))
3349 {
3350 snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid));
3351 return buf;
3352 }
3353
3354 return normal_pid_to_str (ptid);
3355 }
3356
3357 /* Accepts an integer PID; Returns a string representing a file that
3358 can be opened to get the symbols for the child process. */
3359
3360 static char *
3361 linux_child_pid_to_exec_file (int pid)
3362 {
3363 char *name1, *name2;
3364
3365 name1 = xmalloc (MAXPATHLEN);
3366 name2 = xmalloc (MAXPATHLEN);
3367 make_cleanup (xfree, name1);
3368 make_cleanup (xfree, name2);
3369 memset (name2, 0, MAXPATHLEN);
3370
3371 sprintf (name1, "/proc/%d/exe", pid);
3372 if (readlink (name1, name2, MAXPATHLEN) > 0)
3373 return name2;
3374 else
3375 return name1;
3376 }
3377
3378 /* Service function for corefiles and info proc. */
3379
3380 static int
3381 read_mapping (FILE *mapfile,
3382 long long *addr,
3383 long long *endaddr,
3384 char *permissions,
3385 long long *offset,
3386 char *device, long long *inode, char *filename)
3387 {
3388 int ret = fscanf (mapfile, "%llx-%llx %s %llx %s %llx",
3389 addr, endaddr, permissions, offset, device, inode);
3390
3391 filename[0] = '\0';
3392 if (ret > 0 && ret != EOF)
3393 {
3394 /* Eat everything up to EOL for the filename. This will prevent
3395 weird filenames (such as one with embedded whitespace) from
3396 confusing this code. It also makes this code more robust in
3397 respect to annotations the kernel may add after the filename.
3398
3399 Note the filename is used for informational purposes
3400 only. */
3401 ret += fscanf (mapfile, "%[^\n]\n", filename);
3402 }
3403
3404 return (ret != 0 && ret != EOF);
3405 }
3406
3407 /* Fills the "to_find_memory_regions" target vector. Lists the memory
3408 regions in the inferior for a corefile. */
3409
3410 static int
3411 linux_nat_find_memory_regions (int (*func) (CORE_ADDR,
3412 unsigned long,
3413 int, int, int, void *), void *obfd)
3414 {
3415 int pid = PIDGET (inferior_ptid);
3416 char mapsfilename[MAXPATHLEN];
3417 FILE *mapsfile;
3418 long long addr, endaddr, size, offset, inode;
3419 char permissions[8], device[8], filename[MAXPATHLEN];
3420 int read, write, exec;
3421 int ret;
3422 struct cleanup *cleanup;
3423
3424 /* Compose the filename for the /proc memory map, and open it. */
3425 sprintf (mapsfilename, "/proc/%d/maps", pid);
3426 if ((mapsfile = fopen (mapsfilename, "r")) == NULL)
3427 error (_("Could not open %s."), mapsfilename);
3428 cleanup = make_cleanup_fclose (mapsfile);
3429
3430 if (info_verbose)
3431 fprintf_filtered (gdb_stdout,
3432 "Reading memory regions from %s\n", mapsfilename);
3433
3434 /* Now iterate until end-of-file. */
3435 while (read_mapping (mapsfile, &addr, &endaddr, &permissions[0],
3436 &offset, &device[0], &inode, &filename[0]))
3437 {
3438 size = endaddr - addr;
3439
3440 /* Get the segment's permissions. */
3441 read = (strchr (permissions, 'r') != 0);
3442 write = (strchr (permissions, 'w') != 0);
3443 exec = (strchr (permissions, 'x') != 0);
3444
3445 if (info_verbose)
3446 {
3447 fprintf_filtered (gdb_stdout,
3448 "Save segment, %lld bytes at 0x%s (%c%c%c)",
3449 size, paddr_nz (addr),
3450 read ? 'r' : ' ',
3451 write ? 'w' : ' ', exec ? 'x' : ' ');
3452 if (filename[0])
3453 fprintf_filtered (gdb_stdout, " for %s", filename);
3454 fprintf_filtered (gdb_stdout, "\n");
3455 }
3456
3457 /* Invoke the callback function to create the corefile
3458 segment. */
3459 func (addr, size, read, write, exec, obfd);
3460 }
3461 do_cleanups (cleanup);
3462 return 0;
3463 }
3464
3465 static int
3466 find_signalled_thread (struct thread_info *info, void *data)
3467 {
3468 if (info->stop_signal != TARGET_SIGNAL_0
3469 && ptid_get_pid (info->ptid) == ptid_get_pid (inferior_ptid))
3470 return 1;
3471
3472 return 0;
3473 }
3474
3475 static enum target_signal
3476 find_stop_signal (void)
3477 {
3478 struct thread_info *info =
3479 iterate_over_threads (find_signalled_thread, NULL);
3480
3481 if (info)
3482 return info->stop_signal;
3483 else
3484 return TARGET_SIGNAL_0;
3485 }
3486
3487 /* Records the thread's register state for the corefile note
3488 section. */
3489
3490 static char *
3491 linux_nat_do_thread_registers (bfd *obfd, ptid_t ptid,
3492 char *note_data, int *note_size,
3493 enum target_signal stop_signal)
3494 {
3495 gdb_gregset_t gregs;
3496 gdb_fpregset_t fpregs;
3497 unsigned long lwp = ptid_get_lwp (ptid);
3498 struct regcache *regcache = get_thread_regcache (ptid);
3499 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3500 const struct regset *regset;
3501 int core_regset_p;
3502 struct cleanup *old_chain;
3503 struct core_regset_section *sect_list;
3504 char *gdb_regset;
3505
3506 old_chain = save_inferior_ptid ();
3507 inferior_ptid = ptid;
3508 target_fetch_registers (regcache, -1);
3509 do_cleanups (old_chain);
3510
3511 core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
3512 sect_list = gdbarch_core_regset_sections (gdbarch);
3513
3514 if (core_regset_p
3515 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
3516 sizeof (gregs))) != NULL
3517 && regset->collect_regset != NULL)
3518 regset->collect_regset (regset, regcache, -1,
3519 &gregs, sizeof (gregs));
3520 else
3521 fill_gregset (regcache, &gregs, -1);
3522
3523 note_data = (char *) elfcore_write_prstatus (obfd,
3524 note_data,
3525 note_size,
3526 lwp,
3527 stop_signal, &gregs);
3528
3529 /* The loop below uses the new struct core_regset_section, which stores
3530 the supported section names and sizes for the core file. Note that
3531 note PRSTATUS needs to be treated specially. But the other notes are
3532 structurally the same, so they can benefit from the new struct. */
3533 if (core_regset_p && sect_list != NULL)
3534 while (sect_list->sect_name != NULL)
3535 {
3536 /* .reg was already handled above. */
3537 if (strcmp (sect_list->sect_name, ".reg") == 0)
3538 {
3539 sect_list++;
3540 continue;
3541 }
3542 regset = gdbarch_regset_from_core_section (gdbarch,
3543 sect_list->sect_name,
3544 sect_list->size);
3545 gdb_assert (regset && regset->collect_regset);
3546 gdb_regset = xmalloc (sect_list->size);
3547 regset->collect_regset (regset, regcache, -1,
3548 gdb_regset, sect_list->size);
3549 note_data = (char *) elfcore_write_register_note (obfd,
3550 note_data,
3551 note_size,
3552 sect_list->sect_name,
3553 gdb_regset,
3554 sect_list->size);
3555 xfree (gdb_regset);
3556 sect_list++;
3557 }
3558
3559 /* For architectures that does not have the struct core_regset_section
3560 implemented, we use the old method. When all the architectures have
3561 the new support, the code below should be deleted. */
3562 else
3563 {
3564 if (core_regset_p
3565 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
3566 sizeof (fpregs))) != NULL
3567 && regset->collect_regset != NULL)
3568 regset->collect_regset (regset, regcache, -1,
3569 &fpregs, sizeof (fpregs));
3570 else
3571 fill_fpregset (regcache, &fpregs, -1);
3572
3573 note_data = (char *) elfcore_write_prfpreg (obfd,
3574 note_data,
3575 note_size,
3576 &fpregs, sizeof (fpregs));
3577 }
3578
3579 return note_data;
3580 }
3581
3582 struct linux_nat_corefile_thread_data
3583 {
3584 bfd *obfd;
3585 char *note_data;
3586 int *note_size;
3587 int num_notes;
3588 enum target_signal stop_signal;
3589 };
3590
3591 /* Called by gdbthread.c once per thread. Records the thread's
3592 register state for the corefile note section. */
3593
3594 static int
3595 linux_nat_corefile_thread_callback (struct lwp_info *ti, void *data)
3596 {
3597 struct linux_nat_corefile_thread_data *args = data;
3598
3599 args->note_data = linux_nat_do_thread_registers (args->obfd,
3600 ti->ptid,
3601 args->note_data,
3602 args->note_size,
3603 args->stop_signal);
3604 args->num_notes++;
3605
3606 return 0;
3607 }
3608
3609 /* Fills the "to_make_corefile_note" target vector. Builds the note
3610 section for a corefile, and returns it in a malloc buffer. */
3611
3612 static char *
3613 linux_nat_make_corefile_notes (bfd *obfd, int *note_size)
3614 {
3615 struct linux_nat_corefile_thread_data thread_args;
3616 struct cleanup *old_chain;
3617 /* The variable size must be >= sizeof (prpsinfo_t.pr_fname). */
3618 char fname[16] = { '\0' };
3619 /* The variable size must be >= sizeof (prpsinfo_t.pr_psargs). */
3620 char psargs[80] = { '\0' };
3621 char *note_data = NULL;
3622 ptid_t current_ptid = inferior_ptid;
3623 ptid_t filter = pid_to_ptid (ptid_get_pid (inferior_ptid));
3624 gdb_byte *auxv;
3625 int auxv_len;
3626
3627 if (get_exec_file (0))
3628 {
3629 strncpy (fname, strrchr (get_exec_file (0), '/') + 1, sizeof (fname));
3630 strncpy (psargs, get_exec_file (0), sizeof (psargs));
3631 if (get_inferior_args ())
3632 {
3633 char *string_end;
3634 char *psargs_end = psargs + sizeof (psargs);
3635
3636 /* linux_elfcore_write_prpsinfo () handles zero unterminated
3637 strings fine. */
3638 string_end = memchr (psargs, 0, sizeof (psargs));
3639 if (string_end != NULL)
3640 {
3641 *string_end++ = ' ';
3642 strncpy (string_end, get_inferior_args (),
3643 psargs_end - string_end);
3644 }
3645 }
3646 note_data = (char *) elfcore_write_prpsinfo (obfd,
3647 note_data,
3648 note_size, fname, psargs);
3649 }
3650
3651 /* Dump information for threads. */
3652 thread_args.obfd = obfd;
3653 thread_args.note_data = note_data;
3654 thread_args.note_size = note_size;
3655 thread_args.num_notes = 0;
3656 thread_args.stop_signal = find_stop_signal ();
3657 iterate_over_lwps (filter, linux_nat_corefile_thread_callback, &thread_args);
3658 gdb_assert (thread_args.num_notes != 0);
3659 note_data = thread_args.note_data;
3660
3661 auxv_len = target_read_alloc (&current_target, TARGET_OBJECT_AUXV,
3662 NULL, &auxv);
3663 if (auxv_len > 0)
3664 {
3665 note_data = elfcore_write_note (obfd, note_data, note_size,
3666 "CORE", NT_AUXV, auxv, auxv_len);
3667 xfree (auxv);
3668 }
3669
3670 make_cleanup (xfree, note_data);
3671 return note_data;
3672 }
3673
3674 /* Implement the "info proc" command. */
3675
3676 static void
3677 linux_nat_info_proc_cmd (char *args, int from_tty)
3678 {
3679 /* A long is used for pid instead of an int to avoid a loss of precision
3680 compiler warning from the output of strtoul. */
3681 long pid = PIDGET (inferior_ptid);
3682 FILE *procfile;
3683 char **argv = NULL;
3684 char buffer[MAXPATHLEN];
3685 char fname1[MAXPATHLEN], fname2[MAXPATHLEN];
3686 int cmdline_f = 1;
3687 int cwd_f = 1;
3688 int exe_f = 1;
3689 int mappings_f = 0;
3690 int environ_f = 0;
3691 int status_f = 0;
3692 int stat_f = 0;
3693 int all = 0;
3694 struct stat dummy;
3695
3696 if (args)
3697 {
3698 /* Break up 'args' into an argv array. */
3699 argv = gdb_buildargv (args);
3700 make_cleanup_freeargv (argv);
3701 }
3702 while (argv != NULL && *argv != NULL)
3703 {
3704 if (isdigit (argv[0][0]))
3705 {
3706 pid = strtoul (argv[0], NULL, 10);
3707 }
3708 else if (strncmp (argv[0], "mappings", strlen (argv[0])) == 0)
3709 {
3710 mappings_f = 1;
3711 }
3712 else if (strcmp (argv[0], "status") == 0)
3713 {
3714 status_f = 1;
3715 }
3716 else if (strcmp (argv[0], "stat") == 0)
3717 {
3718 stat_f = 1;
3719 }
3720 else if (strcmp (argv[0], "cmd") == 0)
3721 {
3722 cmdline_f = 1;
3723 }
3724 else if (strncmp (argv[0], "exe", strlen (argv[0])) == 0)
3725 {
3726 exe_f = 1;
3727 }
3728 else if (strcmp (argv[0], "cwd") == 0)
3729 {
3730 cwd_f = 1;
3731 }
3732 else if (strncmp (argv[0], "all", strlen (argv[0])) == 0)
3733 {
3734 all = 1;
3735 }
3736 else
3737 {
3738 /* [...] (future options here) */
3739 }
3740 argv++;
3741 }
3742 if (pid == 0)
3743 error (_("No current process: you must name one."));
3744
3745 sprintf (fname1, "/proc/%ld", pid);
3746 if (stat (fname1, &dummy) != 0)
3747 error (_("No /proc directory: '%s'"), fname1);
3748
3749 printf_filtered (_("process %ld\n"), pid);
3750 if (cmdline_f || all)
3751 {
3752 sprintf (fname1, "/proc/%ld/cmdline", pid);
3753 if ((procfile = fopen (fname1, "r")) != NULL)
3754 {
3755 struct cleanup *cleanup = make_cleanup_fclose (procfile);
3756 if (fgets (buffer, sizeof (buffer), procfile))
3757 printf_filtered ("cmdline = '%s'\n", buffer);
3758 else
3759 warning (_("unable to read '%s'"), fname1);
3760 do_cleanups (cleanup);
3761 }
3762 else
3763 warning (_("unable to open /proc file '%s'"), fname1);
3764 }
3765 if (cwd_f || all)
3766 {
3767 sprintf (fname1, "/proc/%ld/cwd", pid);
3768 memset (fname2, 0, sizeof (fname2));
3769 if (readlink (fname1, fname2, sizeof (fname2)) > 0)
3770 printf_filtered ("cwd = '%s'\n", fname2);
3771 else
3772 warning (_("unable to read link '%s'"), fname1);
3773 }
3774 if (exe_f || all)
3775 {
3776 sprintf (fname1, "/proc/%ld/exe", pid);
3777 memset (fname2, 0, sizeof (fname2));
3778 if (readlink (fname1, fname2, sizeof (fname2)) > 0)
3779 printf_filtered ("exe = '%s'\n", fname2);
3780 else
3781 warning (_("unable to read link '%s'"), fname1);
3782 }
3783 if (mappings_f || all)
3784 {
3785 sprintf (fname1, "/proc/%ld/maps", pid);
3786 if ((procfile = fopen (fname1, "r")) != NULL)
3787 {
3788 long long addr, endaddr, size, offset, inode;
3789 char permissions[8], device[8], filename[MAXPATHLEN];
3790 struct cleanup *cleanup;
3791
3792 cleanup = make_cleanup_fclose (procfile);
3793 printf_filtered (_("Mapped address spaces:\n\n"));
3794 if (gdbarch_addr_bit (current_gdbarch) == 32)
3795 {
3796 printf_filtered ("\t%10s %10s %10s %10s %7s\n",
3797 "Start Addr",
3798 " End Addr",
3799 " Size", " Offset", "objfile");
3800 }
3801 else
3802 {
3803 printf_filtered (" %18s %18s %10s %10s %7s\n",
3804 "Start Addr",
3805 " End Addr",
3806 " Size", " Offset", "objfile");
3807 }
3808
3809 while (read_mapping (procfile, &addr, &endaddr, &permissions[0],
3810 &offset, &device[0], &inode, &filename[0]))
3811 {
3812 size = endaddr - addr;
3813
3814 /* FIXME: carlton/2003-08-27: Maybe the printf_filtered
3815 calls here (and possibly above) should be abstracted
3816 out into their own functions? Andrew suggests using
3817 a generic local_address_string instead to print out
3818 the addresses; that makes sense to me, too. */
3819
3820 if (gdbarch_addr_bit (current_gdbarch) == 32)
3821 {
3822 printf_filtered ("\t%#10lx %#10lx %#10x %#10x %7s\n",
3823 (unsigned long) addr, /* FIXME: pr_addr */
3824 (unsigned long) endaddr,
3825 (int) size,
3826 (unsigned int) offset,
3827 filename[0] ? filename : "");
3828 }
3829 else
3830 {
3831 printf_filtered (" %#18lx %#18lx %#10x %#10x %7s\n",
3832 (unsigned long) addr, /* FIXME: pr_addr */
3833 (unsigned long) endaddr,
3834 (int) size,
3835 (unsigned int) offset,
3836 filename[0] ? filename : "");
3837 }
3838 }
3839
3840 do_cleanups (cleanup);
3841 }
3842 else
3843 warning (_("unable to open /proc file '%s'"), fname1);
3844 }
3845 if (status_f || all)
3846 {
3847 sprintf (fname1, "/proc/%ld/status", pid);
3848 if ((procfile = fopen (fname1, "r")) != NULL)
3849 {
3850 struct cleanup *cleanup = make_cleanup_fclose (procfile);
3851 while (fgets (buffer, sizeof (buffer), procfile) != NULL)
3852 puts_filtered (buffer);
3853 do_cleanups (cleanup);
3854 }
3855 else
3856 warning (_("unable to open /proc file '%s'"), fname1);
3857 }
3858 if (stat_f || all)
3859 {
3860 sprintf (fname1, "/proc/%ld/stat", pid);
3861 if ((procfile = fopen (fname1, "r")) != NULL)
3862 {
3863 int itmp;
3864 char ctmp;
3865 long ltmp;
3866 struct cleanup *cleanup = make_cleanup_fclose (procfile);
3867
3868 if (fscanf (procfile, "%d ", &itmp) > 0)
3869 printf_filtered (_("Process: %d\n"), itmp);
3870 if (fscanf (procfile, "(%[^)]) ", &buffer[0]) > 0)
3871 printf_filtered (_("Exec file: %s\n"), buffer);
3872 if (fscanf (procfile, "%c ", &ctmp) > 0)
3873 printf_filtered (_("State: %c\n"), ctmp);
3874 if (fscanf (procfile, "%d ", &itmp) > 0)
3875 printf_filtered (_("Parent process: %d\n"), itmp);
3876 if (fscanf (procfile, "%d ", &itmp) > 0)
3877 printf_filtered (_("Process group: %d\n"), itmp);
3878 if (fscanf (procfile, "%d ", &itmp) > 0)
3879 printf_filtered (_("Session id: %d\n"), itmp);
3880 if (fscanf (procfile, "%d ", &itmp) > 0)
3881 printf_filtered (_("TTY: %d\n"), itmp);
3882 if (fscanf (procfile, "%d ", &itmp) > 0)
3883 printf_filtered (_("TTY owner process group: %d\n"), itmp);
3884 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3885 printf_filtered (_("Flags: 0x%lx\n"), ltmp);
3886 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3887 printf_filtered (_("Minor faults (no memory page): %lu\n"),
3888 (unsigned long) ltmp);
3889 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3890 printf_filtered (_("Minor faults, children: %lu\n"),
3891 (unsigned long) ltmp);
3892 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3893 printf_filtered (_("Major faults (memory page faults): %lu\n"),
3894 (unsigned long) ltmp);
3895 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3896 printf_filtered (_("Major faults, children: %lu\n"),
3897 (unsigned long) ltmp);
3898 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3899 printf_filtered (_("utime: %ld\n"), ltmp);
3900 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3901 printf_filtered (_("stime: %ld\n"), ltmp);
3902 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3903 printf_filtered (_("utime, children: %ld\n"), ltmp);
3904 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3905 printf_filtered (_("stime, children: %ld\n"), ltmp);
3906 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3907 printf_filtered (_("jiffies remaining in current time slice: %ld\n"),
3908 ltmp);
3909 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3910 printf_filtered (_("'nice' value: %ld\n"), ltmp);
3911 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3912 printf_filtered (_("jiffies until next timeout: %lu\n"),
3913 (unsigned long) ltmp);
3914 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3915 printf_filtered (_("jiffies until next SIGALRM: %lu\n"),
3916 (unsigned long) ltmp);
3917 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3918 printf_filtered (_("start time (jiffies since system boot): %ld\n"),
3919 ltmp);
3920 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3921 printf_filtered (_("Virtual memory size: %lu\n"),
3922 (unsigned long) ltmp);
3923 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3924 printf_filtered (_("Resident set size: %lu\n"), (unsigned long) ltmp);
3925 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3926 printf_filtered (_("rlim: %lu\n"), (unsigned long) ltmp);
3927 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3928 printf_filtered (_("Start of text: 0x%lx\n"), ltmp);
3929 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3930 printf_filtered (_("End of text: 0x%lx\n"), ltmp);
3931 if (fscanf (procfile, "%lu ", &ltmp) > 0)
3932 printf_filtered (_("Start of stack: 0x%lx\n"), ltmp);
3933 #if 0 /* Don't know how architecture-dependent the rest is...
3934 Anyway the signal bitmap info is available from "status". */
3935 if (fscanf (procfile, "%lu ", &ltmp) > 0) /* FIXME arch? */
3936 printf_filtered (_("Kernel stack pointer: 0x%lx\n"), ltmp);
3937 if (fscanf (procfile, "%lu ", &ltmp) > 0) /* FIXME arch? */
3938 printf_filtered (_("Kernel instr pointer: 0x%lx\n"), ltmp);
3939 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3940 printf_filtered (_("Pending signals bitmap: 0x%lx\n"), ltmp);
3941 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3942 printf_filtered (_("Blocked signals bitmap: 0x%lx\n"), ltmp);
3943 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3944 printf_filtered (_("Ignored signals bitmap: 0x%lx\n"), ltmp);
3945 if (fscanf (procfile, "%ld ", &ltmp) > 0)
3946 printf_filtered (_("Catched signals bitmap: 0x%lx\n"), ltmp);
3947 if (fscanf (procfile, "%lu ", &ltmp) > 0) /* FIXME arch? */
3948 printf_filtered (_("wchan (system call): 0x%lx\n"), ltmp);
3949 #endif
3950 do_cleanups (cleanup);
3951 }
3952 else
3953 warning (_("unable to open /proc file '%s'"), fname1);
3954 }
3955 }
3956
3957 /* Implement the to_xfer_partial interface for memory reads using the /proc
3958 filesystem. Because we can use a single read() call for /proc, this
3959 can be much more efficient than banging away at PTRACE_PEEKTEXT,
3960 but it doesn't support writes. */
3961
3962 static LONGEST
3963 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
3964 const char *annex, gdb_byte *readbuf,
3965 const gdb_byte *writebuf,
3966 ULONGEST offset, LONGEST len)
3967 {
3968 LONGEST ret;
3969 int fd;
3970 char filename[64];
3971
3972 if (object != TARGET_OBJECT_MEMORY || !readbuf)
3973 return 0;
3974
3975 /* Don't bother for one word. */
3976 if (len < 3 * sizeof (long))
3977 return 0;
3978
3979 /* We could keep this file open and cache it - possibly one per
3980 thread. That requires some juggling, but is even faster. */
3981 sprintf (filename, "/proc/%d/mem", PIDGET (inferior_ptid));
3982 fd = open (filename, O_RDONLY | O_LARGEFILE);
3983 if (fd == -1)
3984 return 0;
3985
3986 /* If pread64 is available, use it. It's faster if the kernel
3987 supports it (only one syscall), and it's 64-bit safe even on
3988 32-bit platforms (for instance, SPARC debugging a SPARC64
3989 application). */
3990 #ifdef HAVE_PREAD64
3991 if (pread64 (fd, readbuf, len, offset) != len)
3992 #else
3993 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
3994 #endif
3995 ret = 0;
3996 else
3997 ret = len;
3998
3999 close (fd);
4000 return ret;
4001 }
4002
4003 /* Parse LINE as a signal set and add its set bits to SIGS. */
4004
4005 static void
4006 add_line_to_sigset (const char *line, sigset_t *sigs)
4007 {
4008 int len = strlen (line) - 1;
4009 const char *p;
4010 int signum;
4011
4012 if (line[len] != '\n')
4013 error (_("Could not parse signal set: %s"), line);
4014
4015 p = line;
4016 signum = len * 4;
4017 while (len-- > 0)
4018 {
4019 int digit;
4020
4021 if (*p >= '0' && *p <= '9')
4022 digit = *p - '0';
4023 else if (*p >= 'a' && *p <= 'f')
4024 digit = *p - 'a' + 10;
4025 else
4026 error (_("Could not parse signal set: %s"), line);
4027
4028 signum -= 4;
4029
4030 if (digit & 1)
4031 sigaddset (sigs, signum + 1);
4032 if (digit & 2)
4033 sigaddset (sigs, signum + 2);
4034 if (digit & 4)
4035 sigaddset (sigs, signum + 3);
4036 if (digit & 8)
4037 sigaddset (sigs, signum + 4);
4038
4039 p++;
4040 }
4041 }
4042
4043 /* Find process PID's pending signals from /proc/pid/status and set
4044 SIGS to match. */
4045
4046 void
4047 linux_proc_pending_signals (int pid, sigset_t *pending, sigset_t *blocked, sigset_t *ignored)
4048 {
4049 FILE *procfile;
4050 char buffer[MAXPATHLEN], fname[MAXPATHLEN];
4051 int signum;
4052 struct cleanup *cleanup;
4053
4054 sigemptyset (pending);
4055 sigemptyset (blocked);
4056 sigemptyset (ignored);
4057 sprintf (fname, "/proc/%d/status", pid);
4058 procfile = fopen (fname, "r");
4059 if (procfile == NULL)
4060 error (_("Could not open %s"), fname);
4061 cleanup = make_cleanup_fclose (procfile);
4062
4063 while (fgets (buffer, MAXPATHLEN, procfile) != NULL)
4064 {
4065 /* Normal queued signals are on the SigPnd line in the status
4066 file. However, 2.6 kernels also have a "shared" pending
4067 queue for delivering signals to a thread group, so check for
4068 a ShdPnd line also.
4069
4070 Unfortunately some Red Hat kernels include the shared pending
4071 queue but not the ShdPnd status field. */
4072
4073 if (strncmp (buffer, "SigPnd:\t", 8) == 0)
4074 add_line_to_sigset (buffer + 8, pending);
4075 else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
4076 add_line_to_sigset (buffer + 8, pending);
4077 else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
4078 add_line_to_sigset (buffer + 8, blocked);
4079 else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
4080 add_line_to_sigset (buffer + 8, ignored);
4081 }
4082
4083 do_cleanups (cleanup);
4084 }
4085
4086 static LONGEST
4087 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4088 const char *annex, gdb_byte *readbuf,
4089 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
4090 {
4091 /* We make the process list snapshot when the object starts to be
4092 read. */
4093 static const char *buf;
4094 static LONGEST len_avail = -1;
4095 static struct obstack obstack;
4096
4097 DIR *dirp;
4098
4099 gdb_assert (object == TARGET_OBJECT_OSDATA);
4100
4101 if (strcmp (annex, "processes") != 0)
4102 return 0;
4103
4104 gdb_assert (readbuf && !writebuf);
4105
4106 if (offset == 0)
4107 {
4108 if (len_avail != -1 && len_avail != 0)
4109 obstack_free (&obstack, NULL);
4110 len_avail = 0;
4111 buf = NULL;
4112 obstack_init (&obstack);
4113 obstack_grow_str (&obstack, "<osdata type=\"processes\">\n");
4114
4115 dirp = opendir ("/proc");
4116 if (dirp)
4117 {
4118 struct dirent *dp;
4119 while ((dp = readdir (dirp)) != NULL)
4120 {
4121 struct stat statbuf;
4122 char procentry[sizeof ("/proc/4294967295")];
4123
4124 if (!isdigit (dp->d_name[0])
4125 || NAMELEN (dp) > sizeof ("4294967295") - 1)
4126 continue;
4127
4128 sprintf (procentry, "/proc/%s", dp->d_name);
4129 if (stat (procentry, &statbuf) == 0
4130 && S_ISDIR (statbuf.st_mode))
4131 {
4132 char *pathname;
4133 FILE *f;
4134 char cmd[MAXPATHLEN + 1];
4135 struct passwd *entry;
4136
4137 pathname = xstrprintf ("/proc/%s/cmdline", dp->d_name);
4138 entry = getpwuid (statbuf.st_uid);
4139
4140 if ((f = fopen (pathname, "r")) != NULL)
4141 {
4142 size_t len = fread (cmd, 1, sizeof (cmd) - 1, f);
4143 if (len > 0)
4144 {
4145 int i;
4146 for (i = 0; i < len; i++)
4147 if (cmd[i] == '\0')
4148 cmd[i] = ' ';
4149 cmd[len] = '\0';
4150
4151 obstack_xml_printf (
4152 &obstack,
4153 "<item>"
4154 "<column name=\"pid\">%s</column>"
4155 "<column name=\"user\">%s</column>"
4156 "<column name=\"command\">%s</column>"
4157 "</item>",
4158 dp->d_name,
4159 entry ? entry->pw_name : "?",
4160 cmd);
4161 }
4162 fclose (f);
4163 }
4164
4165 xfree (pathname);
4166 }
4167 }
4168
4169 closedir (dirp);
4170 }
4171
4172 obstack_grow_str0 (&obstack, "</osdata>\n");
4173 buf = obstack_finish (&obstack);
4174 len_avail = strlen (buf);
4175 }
4176
4177 if (offset >= len_avail)
4178 {
4179 /* Done. Get rid of the obstack. */
4180 obstack_free (&obstack, NULL);
4181 buf = NULL;
4182 len_avail = 0;
4183 return 0;
4184 }
4185
4186 if (len > len_avail - offset)
4187 len = len_avail - offset;
4188 memcpy (readbuf, buf + offset, len);
4189
4190 return len;
4191 }
4192
4193 static LONGEST
4194 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4195 const char *annex, gdb_byte *readbuf,
4196 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
4197 {
4198 LONGEST xfer;
4199
4200 if (object == TARGET_OBJECT_AUXV)
4201 return procfs_xfer_auxv (ops, object, annex, readbuf, writebuf,
4202 offset, len);
4203
4204 if (object == TARGET_OBJECT_OSDATA)
4205 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4206 offset, len);
4207
4208 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4209 offset, len);
4210 if (xfer != 0)
4211 return xfer;
4212
4213 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4214 offset, len);
4215 }
4216
4217 /* Create a prototype generic GNU/Linux target. The client can override
4218 it with local methods. */
4219
4220 static void
4221 linux_target_install_ops (struct target_ops *t)
4222 {
4223 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4224 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4225 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4226 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4227 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4228 t->to_post_attach = linux_child_post_attach;
4229 t->to_follow_fork = linux_child_follow_fork;
4230 t->to_find_memory_regions = linux_nat_find_memory_regions;
4231 t->to_make_corefile_notes = linux_nat_make_corefile_notes;
4232
4233 super_xfer_partial = t->to_xfer_partial;
4234 t->to_xfer_partial = linux_xfer_partial;
4235 }
4236
4237 struct target_ops *
4238 linux_target (void)
4239 {
4240 struct target_ops *t;
4241
4242 t = inf_ptrace_target ();
4243 linux_target_install_ops (t);
4244
4245 return t;
4246 }
4247
4248 struct target_ops *
4249 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4250 {
4251 struct target_ops *t;
4252
4253 t = inf_ptrace_trad_target (register_u_offset);
4254 linux_target_install_ops (t);
4255
4256 return t;
4257 }
4258
4259 /* target_is_async_p implementation. */
4260
4261 static int
4262 linux_nat_is_async_p (void)
4263 {
4264 /* NOTE: palves 2008-03-21: We're only async when the user requests
4265 it explicitly with the "set target-async" command.
4266 Someday, linux will always be async. */
4267 if (!target_async_permitted)
4268 return 0;
4269
4270 /* See target.h/target_async_mask. */
4271 return linux_nat_async_mask_value;
4272 }
4273
4274 /* target_can_async_p implementation. */
4275
4276 static int
4277 linux_nat_can_async_p (void)
4278 {
4279 /* NOTE: palves 2008-03-21: We're only async when the user requests
4280 it explicitly with the "set target-async" command.
4281 Someday, linux will always be async. */
4282 if (!target_async_permitted)
4283 return 0;
4284
4285 /* See target.h/target_async_mask. */
4286 return linux_nat_async_mask_value;
4287 }
4288
4289 static int
4290 linux_nat_supports_non_stop (void)
4291 {
4292 return 1;
4293 }
4294
4295 /* True if we want to support multi-process. To be removed when GDB
4296 supports multi-exec. */
4297
4298 int linux_multi_process = 0;
4299
4300 static int
4301 linux_nat_supports_multi_process (void)
4302 {
4303 return linux_multi_process;
4304 }
4305
4306 /* target_async_mask implementation. */
4307
4308 static int
4309 linux_nat_async_mask (int new_mask)
4310 {
4311 int curr_mask = linux_nat_async_mask_value;
4312
4313 if (curr_mask != new_mask)
4314 {
4315 if (new_mask == 0)
4316 {
4317 linux_nat_async (NULL, 0);
4318 linux_nat_async_mask_value = new_mask;
4319 }
4320 else
4321 {
4322 linux_nat_async_mask_value = new_mask;
4323
4324 /* If we're going out of async-mask in all-stop, then the
4325 inferior is stopped. The next resume will call
4326 target_async. In non-stop, the target event source
4327 should be always registered in the event loop. Do so
4328 now. */
4329 if (non_stop)
4330 linux_nat_async (inferior_event_handler, 0);
4331 }
4332 }
4333
4334 return curr_mask;
4335 }
4336
4337 static int async_terminal_is_ours = 1;
4338
4339 /* target_terminal_inferior implementation. */
4340
4341 static void
4342 linux_nat_terminal_inferior (void)
4343 {
4344 if (!target_is_async_p ())
4345 {
4346 /* Async mode is disabled. */
4347 terminal_inferior ();
4348 return;
4349 }
4350
4351 terminal_inferior ();
4352
4353 /* Calls to target_terminal_*() are meant to be idempotent. */
4354 if (!async_terminal_is_ours)
4355 return;
4356
4357 delete_file_handler (input_fd);
4358 async_terminal_is_ours = 0;
4359 set_sigint_trap ();
4360 }
4361
4362 /* target_terminal_ours implementation. */
4363
4364 static void
4365 linux_nat_terminal_ours (void)
4366 {
4367 if (!target_is_async_p ())
4368 {
4369 /* Async mode is disabled. */
4370 terminal_ours ();
4371 return;
4372 }
4373
4374 /* GDB should never give the terminal to the inferior if the
4375 inferior is running in the background (run&, continue&, etc.),
4376 but claiming it sure should. */
4377 terminal_ours ();
4378
4379 if (async_terminal_is_ours)
4380 return;
4381
4382 clear_sigint_trap ();
4383 add_file_handler (input_fd, stdin_event_handler, 0);
4384 async_terminal_is_ours = 1;
4385 }
4386
4387 static void (*async_client_callback) (enum inferior_event_type event_type,
4388 void *context);
4389 static void *async_client_context;
4390
4391 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4392 so we notice when any child changes state, and notify the
4393 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4394 above to wait for the arrival of a SIGCHLD. */
4395
4396 static void
4397 sigchld_handler (int signo)
4398 {
4399 int old_errno = errno;
4400
4401 if (debug_linux_nat_async)
4402 fprintf_unfiltered (gdb_stdlog, "sigchld\n");
4403
4404 if (signo == SIGCHLD
4405 && linux_nat_event_pipe[0] != -1)
4406 async_file_mark (); /* Let the event loop know that there are
4407 events to handle. */
4408
4409 errno = old_errno;
4410 }
4411
4412 /* Callback registered with the target events file descriptor. */
4413
4414 static void
4415 handle_target_event (int error, gdb_client_data client_data)
4416 {
4417 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4418 }
4419
4420 /* Create/destroy the target events pipe. Returns previous state. */
4421
4422 static int
4423 linux_async_pipe (int enable)
4424 {
4425 int previous = (linux_nat_event_pipe[0] != -1);
4426
4427 if (previous != enable)
4428 {
4429 sigset_t prev_mask;
4430
4431 block_child_signals (&prev_mask);
4432
4433 if (enable)
4434 {
4435 if (pipe (linux_nat_event_pipe) == -1)
4436 internal_error (__FILE__, __LINE__,
4437 "creating event pipe failed.");
4438
4439 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4440 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4441 }
4442 else
4443 {
4444 close (linux_nat_event_pipe[0]);
4445 close (linux_nat_event_pipe[1]);
4446 linux_nat_event_pipe[0] = -1;
4447 linux_nat_event_pipe[1] = -1;
4448 }
4449
4450 restore_child_signals_mask (&prev_mask);
4451 }
4452
4453 return previous;
4454 }
4455
4456 /* target_async implementation. */
4457
4458 static void
4459 linux_nat_async (void (*callback) (enum inferior_event_type event_type,
4460 void *context), void *context)
4461 {
4462 if (linux_nat_async_mask_value == 0 || !target_async_permitted)
4463 internal_error (__FILE__, __LINE__,
4464 "Calling target_async when async is masked");
4465
4466 if (callback != NULL)
4467 {
4468 async_client_callback = callback;
4469 async_client_context = context;
4470 if (!linux_async_pipe (1))
4471 {
4472 add_file_handler (linux_nat_event_pipe[0],
4473 handle_target_event, NULL);
4474 /* There may be pending events to handle. Tell the event loop
4475 to poll them. */
4476 async_file_mark ();
4477 }
4478 }
4479 else
4480 {
4481 async_client_callback = callback;
4482 async_client_context = context;
4483 delete_file_handler (linux_nat_event_pipe[0]);
4484 linux_async_pipe (0);
4485 }
4486 return;
4487 }
4488
4489 /* Stop an LWP, and push a TARGET_SIGNAL_0 stop status if no other
4490 event came out. */
4491
4492 static int
4493 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4494 {
4495 if (!lwp->stopped)
4496 {
4497 int pid, status;
4498 ptid_t ptid = lwp->ptid;
4499
4500 if (debug_linux_nat)
4501 fprintf_unfiltered (gdb_stdlog,
4502 "LNSL: running -> suspending %s\n",
4503 target_pid_to_str (lwp->ptid));
4504
4505
4506 stop_callback (lwp, NULL);
4507 stop_wait_callback (lwp, NULL);
4508
4509 /* If the lwp exits while we try to stop it, there's nothing
4510 else to do. */
4511 lwp = find_lwp_pid (ptid);
4512 if (lwp == NULL)
4513 return 0;
4514
4515 /* If we didn't collect any signal other than SIGSTOP while
4516 stopping the LWP, push a SIGNAL_0 event. In either case, the
4517 event-loop will end up calling target_wait which will collect
4518 these. */
4519 if (lwp->status == 0)
4520 lwp->status = W_STOPCODE (0);
4521 async_file_mark ();
4522 }
4523 else
4524 {
4525 /* Already known to be stopped; do nothing. */
4526
4527 if (debug_linux_nat)
4528 {
4529 if (find_thread_ptid (lwp->ptid)->stop_requested)
4530 fprintf_unfiltered (gdb_stdlog, "\
4531 LNSL: already stopped/stop_requested %s\n",
4532 target_pid_to_str (lwp->ptid));
4533 else
4534 fprintf_unfiltered (gdb_stdlog, "\
4535 LNSL: already stopped/no stop_requested yet %s\n",
4536 target_pid_to_str (lwp->ptid));
4537 }
4538 }
4539 return 0;
4540 }
4541
4542 static void
4543 linux_nat_stop (ptid_t ptid)
4544 {
4545 if (non_stop)
4546 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4547 else
4548 linux_ops->to_stop (ptid);
4549 }
4550
4551 static void
4552 linux_nat_close (int quitting)
4553 {
4554 /* Unregister from the event loop. */
4555 if (target_is_async_p ())
4556 target_async (NULL, 0);
4557
4558 /* Reset the async_masking. */
4559 linux_nat_async_mask_value = 1;
4560
4561 if (linux_ops->to_close)
4562 linux_ops->to_close (quitting);
4563 }
4564
4565 void
4566 linux_nat_add_target (struct target_ops *t)
4567 {
4568 /* Save the provided single-threaded target. We save this in a separate
4569 variable because another target we've inherited from (e.g. inf-ptrace)
4570 may have saved a pointer to T; we want to use it for the final
4571 process stratum target. */
4572 linux_ops_saved = *t;
4573 linux_ops = &linux_ops_saved;
4574
4575 /* Override some methods for multithreading. */
4576 t->to_create_inferior = linux_nat_create_inferior;
4577 t->to_attach = linux_nat_attach;
4578 t->to_detach = linux_nat_detach;
4579 t->to_resume = linux_nat_resume;
4580 t->to_wait = linux_nat_wait;
4581 t->to_xfer_partial = linux_nat_xfer_partial;
4582 t->to_kill = linux_nat_kill;
4583 t->to_mourn_inferior = linux_nat_mourn_inferior;
4584 t->to_thread_alive = linux_nat_thread_alive;
4585 t->to_pid_to_str = linux_nat_pid_to_str;
4586 t->to_has_thread_control = tc_schedlock;
4587
4588 t->to_can_async_p = linux_nat_can_async_p;
4589 t->to_is_async_p = linux_nat_is_async_p;
4590 t->to_supports_non_stop = linux_nat_supports_non_stop;
4591 t->to_async = linux_nat_async;
4592 t->to_async_mask = linux_nat_async_mask;
4593 t->to_terminal_inferior = linux_nat_terminal_inferior;
4594 t->to_terminal_ours = linux_nat_terminal_ours;
4595 t->to_close = linux_nat_close;
4596
4597 /* Methods for non-stop support. */
4598 t->to_stop = linux_nat_stop;
4599
4600 t->to_supports_multi_process = linux_nat_supports_multi_process;
4601
4602 /* We don't change the stratum; this target will sit at
4603 process_stratum and thread_db will set at thread_stratum. This
4604 is a little strange, since this is a multi-threaded-capable
4605 target, but we want to be on the stack below thread_db, and we
4606 also want to be used for single-threaded processes. */
4607
4608 add_target (t);
4609 }
4610
4611 /* Register a method to call whenever a new thread is attached. */
4612 void
4613 linux_nat_set_new_thread (struct target_ops *t, void (*new_thread) (ptid_t))
4614 {
4615 /* Save the pointer. We only support a single registered instance
4616 of the GNU/Linux native target, so we do not need to map this to
4617 T. */
4618 linux_nat_new_thread = new_thread;
4619 }
4620
4621 /* Register a method that converts a siginfo object between the layout
4622 that ptrace returns, and the layout in the architecture of the
4623 inferior. */
4624 void
4625 linux_nat_set_siginfo_fixup (struct target_ops *t,
4626 int (*siginfo_fixup) (struct siginfo *,
4627 gdb_byte *,
4628 int))
4629 {
4630 /* Save the pointer. */
4631 linux_nat_siginfo_fixup = siginfo_fixup;
4632 }
4633
4634 /* Return the saved siginfo associated with PTID. */
4635 struct siginfo *
4636 linux_nat_get_siginfo (ptid_t ptid)
4637 {
4638 struct lwp_info *lp = find_lwp_pid (ptid);
4639
4640 gdb_assert (lp != NULL);
4641
4642 return &lp->siginfo;
4643 }
4644
4645 /* Provide a prototype to silence -Wmissing-prototypes. */
4646 extern initialize_file_ftype _initialize_linux_nat;
4647
4648 void
4649 _initialize_linux_nat (void)
4650 {
4651 sigset_t mask;
4652
4653 add_info ("proc", linux_nat_info_proc_cmd, _("\
4654 Show /proc process information about any running process.\n\
4655 Specify any process id, or use the program being debugged by default.\n\
4656 Specify any of the following keywords for detailed info:\n\
4657 mappings -- list of mapped memory regions.\n\
4658 stat -- list a bunch of random process info.\n\
4659 status -- list a different bunch of random process info.\n\
4660 all -- list all available /proc info."));
4661
4662 add_setshow_zinteger_cmd ("lin-lwp", class_maintenance,
4663 &debug_linux_nat, _("\
4664 Set debugging of GNU/Linux lwp module."), _("\
4665 Show debugging of GNU/Linux lwp module."), _("\
4666 Enables printf debugging output."),
4667 NULL,
4668 show_debug_linux_nat,
4669 &setdebuglist, &showdebuglist);
4670
4671 add_setshow_zinteger_cmd ("lin-lwp-async", class_maintenance,
4672 &debug_linux_nat_async, _("\
4673 Set debugging of GNU/Linux async lwp module."), _("\
4674 Show debugging of GNU/Linux async lwp module."), _("\
4675 Enables printf debugging output."),
4676 NULL,
4677 show_debug_linux_nat_async,
4678 &setdebuglist, &showdebuglist);
4679
4680 /* Save this mask as the default. */
4681 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4682
4683 /* Install a SIGCHLD handler. */
4684 sigchld_action.sa_handler = sigchld_handler;
4685 sigemptyset (&sigchld_action.sa_mask);
4686 sigchld_action.sa_flags = SA_RESTART;
4687
4688 /* Make it the default. */
4689 sigaction (SIGCHLD, &sigchld_action, NULL);
4690
4691 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4692 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
4693 sigdelset (&suspend_mask, SIGCHLD);
4694
4695 sigemptyset (&blocked_mask);
4696
4697 add_setshow_boolean_cmd ("disable-randomization", class_support,
4698 &disable_randomization, _("\
4699 Set disabling of debuggee's virtual address space randomization."), _("\
4700 Show disabling of debuggee's virtual address space randomization."), _("\
4701 When this mode is on (which is the default), randomization of the virtual\n\
4702 address space is disabled. Standalone programs run with the randomization\n\
4703 enabled by default on some platforms."),
4704 &set_disable_randomization,
4705 &show_disable_randomization,
4706 &setlist, &showlist);
4707 }
4708 \f
4709
4710 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4711 the GNU/Linux Threads library and therefore doesn't really belong
4712 here. */
4713
4714 /* Read variable NAME in the target and return its value if found.
4715 Otherwise return zero. It is assumed that the type of the variable
4716 is `int'. */
4717
4718 static int
4719 get_signo (const char *name)
4720 {
4721 struct minimal_symbol *ms;
4722 int signo;
4723
4724 ms = lookup_minimal_symbol (name, NULL, NULL);
4725 if (ms == NULL)
4726 return 0;
4727
4728 if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
4729 sizeof (signo)) != 0)
4730 return 0;
4731
4732 return signo;
4733 }
4734
4735 /* Return the set of signals used by the threads library in *SET. */
4736
4737 void
4738 lin_thread_get_thread_signals (sigset_t *set)
4739 {
4740 struct sigaction action;
4741 int restart, cancel;
4742
4743 sigemptyset (&blocked_mask);
4744 sigemptyset (set);
4745
4746 restart = get_signo ("__pthread_sig_restart");
4747 cancel = get_signo ("__pthread_sig_cancel");
4748
4749 /* LinuxThreads normally uses the first two RT signals, but in some legacy
4750 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
4751 not provide any way for the debugger to query the signal numbers -
4752 fortunately they don't change! */
4753
4754 if (restart == 0)
4755 restart = __SIGRTMIN;
4756
4757 if (cancel == 0)
4758 cancel = __SIGRTMIN + 1;
4759
4760 sigaddset (set, restart);
4761 sigaddset (set, cancel);
4762
4763 /* The GNU/Linux Threads library makes terminating threads send a
4764 special "cancel" signal instead of SIGCHLD. Make sure we catch
4765 those (to prevent them from terminating GDB itself, which is
4766 likely to be their default action) and treat them the same way as
4767 SIGCHLD. */
4768
4769 action.sa_handler = sigchld_handler;
4770 sigemptyset (&action.sa_mask);
4771 action.sa_flags = SA_RESTART;
4772 sigaction (cancel, &action, NULL);
4773
4774 /* We block the "cancel" signal throughout this code ... */
4775 sigaddset (&blocked_mask, cancel);
4776 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
4777
4778 /* ... except during a sigsuspend. */
4779 sigdelset (&suspend_mask, cancel);
4780 }