1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
4 Free Software Foundation, Inc.
6 This file is part of GDB.
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.
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.
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/>. */
24 #include "gdb_string.h"
26 #include "gdb_assert.h"
27 #ifdef HAVE_TKILL_SYSCALL
29 #include <sys/syscall.h>
31 #include <sys/ptrace.h>
32 #include "linux-nat.h"
33 #include "linux-fork.h"
34 #include "gdbthread.h"
38 #include "inf-ptrace.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 */
50 #include "event-loop.h"
51 #include "event-top.h"
53 #include <sys/types.h>
54 #include "gdb_dirent.h"
55 #include "xml-support.h"
58 #ifdef HAVE_PERSONALITY
59 # include <sys/personality.h>
60 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
61 # define ADDR_NO_RANDOMIZE 0x0040000
63 #endif /* HAVE_PERSONALITY */
65 /* This comment documents high-level logic of this file.
67 Waiting for events in sync mode
68 ===============================
70 When waiting for an event in a specific thread, we just use waitpid, passing
71 the specific pid, and not passing WNOHANG.
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.
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.
90 Waiting for events in async mode
91 ================================
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).
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.
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
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.
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.
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.
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).
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
153 #define O_LARGEFILE 0
156 /* If the system headers did not provide the constants, hard-code the normal
158 #ifndef PTRACE_EVENT_FORK
160 #define PTRACE_SETOPTIONS 0x4200
161 #define PTRACE_GETEVENTMSG 0x4201
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
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
180 #endif /* PTRACE_EVENT_FORK */
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
186 #define __WALL 0x40000000 /* Wait for any child. */
189 #ifndef PTRACE_GETSIGINFO
190 # define PTRACE_GETSIGINFO 0x4202
191 # define PTRACE_SETSIGINFO 0x4203
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
;
199 /* The method to call, if any, when a new thread is attached. */
200 static void (*linux_nat_new_thread
) (ptid_t
);
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
*,
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
*,
213 const char *, gdb_byte
*,
217 static int debug_linux_nat
;
219 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
220 struct cmd_list_element
*c
, const char *value
)
222 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
226 static int debug_linux_nat_async
= 0;
228 show_debug_linux_nat_async (struct ui_file
*file
, int from_tty
,
229 struct cmd_list_element
*c
, const char *value
)
231 fprintf_filtered (file
, _("Debugging of GNU/Linux async lwp module is %s.\n"),
235 static int disable_randomization
= 1;
238 show_disable_randomization (struct ui_file
*file
, int from_tty
,
239 struct cmd_list_element
*c
, const char *value
)
241 #ifdef HAVE_PERSONALITY
242 fprintf_filtered (file
, _("\
243 Disabling randomization of debuggee's virtual address space is %s.\n"),
245 #else /* !HAVE_PERSONALITY */
247 Disabling randomization of debuggee's virtual address space is unsupported on\n\
248 this platform.\n"), file
);
249 #endif /* !HAVE_PERSONALITY */
253 set_disable_randomization (char *args
, int from_tty
, struct cmd_list_element
*c
)
255 #ifndef HAVE_PERSONALITY
257 Disabling randomization of debuggee's virtual address space is unsupported on\n\
259 #endif /* !HAVE_PERSONALITY */
262 static int linux_parent_pid
;
264 struct simple_pid_list
268 struct simple_pid_list
*next
;
270 struct simple_pid_list
*stopped_pids
;
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. */
275 static int linux_supports_tracefork_flag
= -1;
277 /* If we have PTRACE_O_TRACEFORK, this flag indicates whether we also have
278 PTRACE_O_TRACEVFORKDONE. */
280 static int linux_supports_tracevforkdone_flag
= -1;
282 /* Async mode support */
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;
288 /* The read/write ends of the pipe registered as waitable file in the
290 static int linux_nat_event_pipe
[2] = { -1, -1 };
292 /* Flush the event pipe. */
295 async_file_flush (void)
302 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
304 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
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. */
312 async_file_mark (void)
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
323 ret
= write (linux_nat_event_pipe
[1], "+", 1);
325 while (ret
== -1 && errno
== EINTR
);
327 /* Ignore EAGAIN. If the pipe is full, the event loop will already
328 be awakened anyway. */
331 static void linux_nat_async (void (*callback
)
332 (enum inferior_event_type event_type
, void *context
),
334 static int linux_nat_async_mask (int mask
);
335 static int kill_lwp (int lwpid
, int signo
);
337 static int stop_callback (struct lwp_info
*lp
, void *data
);
339 static void block_child_signals (sigset_t
*prev_mask
);
340 static void restore_child_signals_mask (sigset_t
*prev_mask
);
342 /* Trivial list manipulation functions to keep track of a list of
343 new stopped processes. */
345 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
347 struct simple_pid_list
*new_pid
= xmalloc (sizeof (struct simple_pid_list
));
349 new_pid
->status
= status
;
350 new_pid
->next
= *listp
;
355 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *status
)
357 struct simple_pid_list
**p
;
359 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
360 if ((*p
)->pid
== pid
)
362 struct simple_pid_list
*next
= (*p
)->next
;
363 *status
= (*p
)->status
;
372 linux_record_stopped_pid (int pid
, int status
)
374 add_to_pid_list (&stopped_pids
, pid
, status
);
378 /* A helper function for linux_test_for_tracefork, called after fork (). */
381 linux_tracefork_child (void)
385 ptrace (PTRACE_TRACEME
, 0, 0, 0);
386 kill (getpid (), SIGSTOP
);
391 /* Wrapper function for waitpid which handles EINTR. */
394 my_waitpid (int pid
, int *status
, int flags
)
400 ret
= waitpid (pid
, status
, flags
);
402 while (ret
== -1 && errno
== EINTR
);
407 /* Determine if PTRACE_O_TRACEFORK can be used to follow fork events.
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.
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. */
421 linux_test_for_tracefork (int original_pid
)
423 int child_pid
, ret
, status
;
427 /* We don't want those ptrace calls to be interrupted. */
428 block_child_signals (&prev_mask
);
430 linux_supports_tracefork_flag
= 0;
431 linux_supports_tracevforkdone_flag
= 0;
433 ret
= ptrace (PTRACE_SETOPTIONS
, original_pid
, 0, PTRACE_O_TRACEFORK
);
436 restore_child_signals_mask (&prev_mask
);
442 perror_with_name (("fork"));
445 linux_tracefork_child ();
447 ret
= my_waitpid (child_pid
, &status
, 0);
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
);
455 ret
= ptrace (PTRACE_SETOPTIONS
, child_pid
, 0, PTRACE_O_TRACEFORK
);
458 ret
= ptrace (PTRACE_KILL
, child_pid
, 0, 0);
461 warning (_("linux_test_for_tracefork: failed to kill child"));
462 restore_child_signals_mask (&prev_mask
);
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
);
473 restore_child_signals_mask (&prev_mask
);
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);
482 ret
= ptrace (PTRACE_CONT
, child_pid
, 0, 0);
484 warning (_("linux_test_for_tracefork: failed to resume child"));
486 ret
= my_waitpid (child_pid
, &status
, 0);
488 if (ret
== child_pid
&& WIFSTOPPED (status
)
489 && status
>> 16 == PTRACE_EVENT_FORK
)
492 ret
= ptrace (PTRACE_GETEVENTMSG
, child_pid
, 0, &second_pid
);
493 if (ret
== 0 && second_pid
!= 0)
497 linux_supports_tracefork_flag
= 1;
498 my_waitpid (second_pid
, &second_status
, 0);
499 ret
= ptrace (PTRACE_KILL
, second_pid
, 0, 0);
501 warning (_("linux_test_for_tracefork: failed to kill second child"));
502 my_waitpid (second_pid
, &status
, 0);
506 warning (_("linux_test_for_tracefork: unexpected result from waitpid "
507 "(%d, status 0x%x)"), ret
, status
);
509 ret
= ptrace (PTRACE_KILL
, child_pid
, 0, 0);
511 warning (_("linux_test_for_tracefork: failed to kill child"));
512 my_waitpid (child_pid
, &status
, 0);
514 restore_child_signals_mask (&prev_mask
);
517 /* Return non-zero iff we have tracefork functionality available.
518 This function also sets linux_supports_tracefork_flag. */
521 linux_supports_tracefork (int pid
)
523 if (linux_supports_tracefork_flag
== -1)
524 linux_test_for_tracefork (pid
);
525 return linux_supports_tracefork_flag
;
529 linux_supports_tracevforkdone (int pid
)
531 if (linux_supports_tracefork_flag
== -1)
532 linux_test_for_tracefork (pid
);
533 return linux_supports_tracevforkdone_flag
;
538 linux_enable_event_reporting (ptid_t ptid
)
540 int pid
= ptid_get_lwp (ptid
);
544 pid
= ptid_get_pid (ptid
);
546 if (! linux_supports_tracefork (pid
))
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
;
554 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to support
555 read-only process state. */
557 ptrace (PTRACE_SETOPTIONS
, pid
, 0, options
);
561 linux_child_post_attach (int pid
)
563 linux_enable_event_reporting (pid_to_ptid (pid
));
564 check_for_thread_db ();
568 linux_child_post_startup_inferior (ptid_t ptid
)
570 linux_enable_event_reporting (ptid
);
571 check_for_thread_db ();
575 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
)
579 int parent_pid
, child_pid
;
581 block_child_signals (&prev_mask
);
583 has_vforked
= (inferior_thread ()->pending_follow
.kind
584 == TARGET_WAITKIND_VFORKED
);
585 parent_pid
= ptid_get_lwp (inferior_ptid
);
587 parent_pid
= ptid_get_pid (inferior_ptid
);
588 child_pid
= PIDGET (inferior_thread ()->pending_follow
.value
.related_pid
);
592 /* We're already attached to the parent, by default. */
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. */
603 detach_breakpoints (child_pid
);
605 /* Detach new forked process? */
608 if (info_verbose
|| debug_linux_nat
)
610 target_terminal_ours ();
611 fprintf_filtered (gdb_stdlog
,
612 "Detaching after fork from child process %d.\n",
616 ptrace (PTRACE_DETACH
, child_pid
, 0, 0);
620 struct fork_info
*fp
;
621 struct inferior
*parent_inf
, *child_inf
;
623 /* Add process to GDB's tables. */
624 child_inf
= add_inferior (child_pid
);
626 parent_inf
= current_inferior ();
627 child_inf
->attach_flag
= parent_inf
->attach_flag
;
628 copy_terminal_info (child_inf
, parent_inf
);
630 /* Retain child fork in ptrace (stopped) state. */
631 fp
= find_fork_pid (child_pid
);
633 fp
= add_fork (child_pid
);
634 fork_save_infrun_state (fp
, 0);
639 gdb_assert (linux_supports_tracefork_flag
>= 0);
640 if (linux_supports_tracevforkdone (0))
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
);
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
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
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.
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.
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
686 /* Since we vforked, breakpoints were removed in the parent
687 too. Put them back. */
688 reattach_breakpoints (parent_pid
);
693 struct thread_info
*tp
;
694 struct inferior
*parent_inf
, *child_inf
;
696 /* Before detaching from the parent, remove all breakpoints from it. */
697 remove_breakpoints ();
699 if (info_verbose
|| debug_linux_nat
)
701 target_terminal_ours ();
702 fprintf_filtered (gdb_stdlog
,
703 "Attaching after fork to child process %d.\n",
707 /* Add the new inferior first, so that the target_detach below
708 doesn't unpush the target. */
710 child_inf
= add_inferior (child_pid
);
712 parent_inf
= current_inferior ();
713 child_inf
->attach_flag
= parent_inf
->attach_flag
;
714 copy_terminal_info (child_inf
, parent_inf
);
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).
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
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
736 linux_parent_pid
= parent_pid
;
737 detach_inferior (parent_pid
);
739 else if (!detach_fork
)
741 struct fork_info
*fp
;
742 /* Retain parent fork in ptrace (stopped) state. */
743 fp
= find_fork_pid (parent_pid
);
745 fp
= add_fork (parent_pid
);
746 fork_save_infrun_state (fp
, 0);
748 /* Also add an entry for the child fork. */
749 fp
= find_fork_pid (child_pid
);
751 fp
= add_fork (child_pid
);
752 fork_save_infrun_state (fp
, 0);
755 target_detach (NULL
, 0);
757 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
759 linux_nat_switch_fork (inferior_ptid
);
760 check_for_thread_db ();
763 restore_child_signals_mask (&prev_mask
);
769 linux_child_insert_fork_catchpoint (int pid
)
771 if (! linux_supports_tracefork (pid
))
772 error (_("Your system does not support fork catchpoints."));
776 linux_child_insert_vfork_catchpoint (int pid
)
778 if (!linux_supports_tracefork (pid
))
779 error (_("Your system does not support vfork catchpoints."));
783 linux_child_insert_exec_catchpoint (int pid
)
785 if (!linux_supports_tracefork (pid
))
786 error (_("Your system does not support exec catchpoints."));
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.
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.
804 Note that there are some peculiarities in GNU/Linux that affect
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.
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. */
822 /* List of known LWPs. */
823 struct lwp_info
*lwp_list
;
826 /* Original signal mask. */
827 static sigset_t normal_mask
;
829 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
830 _initialize_linux_nat. */
831 static sigset_t suspend_mask
;
833 /* Signals to block to make that sigsuspend work. */
834 static sigset_t blocked_mask
;
836 /* SIGCHLD action. */
837 struct sigaction sigchld_action
;
839 /* Block child signals (SIGCHLD and linux threads signals), and store
840 the previous mask in PREV_MASK. */
843 block_child_signals (sigset_t
*prev_mask
)
845 /* Make sure SIGCHLD is blocked. */
846 if (!sigismember (&blocked_mask
, SIGCHLD
))
847 sigaddset (&blocked_mask
, SIGCHLD
);
849 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
852 /* Restore child signals mask, previously returned by
853 block_child_signals. */
856 restore_child_signals_mask (sigset_t
*prev_mask
)
858 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
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
);
869 /* Convert wait status STATUS to a string. Used for printing debug
873 status_to_str (int status
)
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
)));
884 snprintf (buf
, sizeof (buf
), "%d (exited)", WEXITSTATUS (status
));
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. */
897 struct lwp_info
*lp
, *lpnext
;
899 for (lp
= lwp_list
; lp
; lp
= lpnext
)
908 /* Remove all LWPs belong to PID from the lwp list. */
911 purge_lwp_list (int pid
)
913 struct lwp_info
*lp
, *lpprev
, *lpnext
;
917 for (lp
= lwp_list
; lp
; lp
= lpnext
)
921 if (ptid_get_pid (lp
->ptid
) == pid
)
926 lpprev
->next
= lp
->next
;
935 /* Return the number of known LWPs in the tgid given by PID. */
943 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
944 if (ptid_get_pid (lp
->ptid
) == pid
)
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). */
954 static struct lwp_info
*
955 add_lwp (ptid_t ptid
)
959 gdb_assert (is_lwp (ptid
));
961 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
963 memset (lp
, 0, sizeof (struct lwp_info
));
965 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
972 if (num_lwps (GET_PID (ptid
)) > 1 && linux_nat_new_thread
!= NULL
)
973 linux_nat_new_thread (ptid
);
978 /* Remove the LWP specified by PID from the list. */
981 delete_lwp (ptid_t ptid
)
983 struct lwp_info
*lp
, *lpprev
;
987 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
988 if (ptid_equal (lp
->ptid
, ptid
))
995 lpprev
->next
= lp
->next
;
1002 /* Return a pointer to the structure describing the LWP corresponding
1003 to PID. If no corresponding LWP could be found, return NULL. */
1005 static struct lwp_info
*
1006 find_lwp_pid (ptid_t ptid
)
1008 struct lwp_info
*lp
;
1012 lwp
= GET_LWP (ptid
);
1014 lwp
= GET_PID (ptid
);
1016 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
1017 if (lwp
== GET_LWP (lp
->ptid
))
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
1032 ptid_match (ptid_t ptid
, ptid_t filter
)
1034 /* Since both parameters have the same type, prevent easy mistakes
1036 gdb_assert (!ptid_equal (ptid
, minus_one_ptid
)
1037 && !ptid_equal (ptid
, null_ptid
));
1039 if (ptid_equal (filter
, minus_one_ptid
))
1041 if (ptid_is_pid (filter
)
1042 && ptid_get_pid (ptid
) == ptid_get_pid (filter
))
1044 else if (ptid_equal (ptid
, filter
))
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. */
1056 iterate_over_lwps (ptid_t filter
,
1057 int (*callback
) (struct lwp_info
*, void *),
1060 struct lwp_info
*lp
, *lpnext
;
1062 for (lp
= lwp_list
; lp
; lp
= lpnext
)
1066 if (ptid_match (lp
->ptid
, filter
))
1068 if ((*callback
) (lp
, data
))
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. */
1082 linux_nat_switch_fork (ptid_t new_ptid
)
1084 struct lwp_info
*lp
;
1087 lp
= add_lwp (new_ptid
);
1090 init_thread_list ();
1091 add_thread_silent (new_ptid
);
1094 /* Handle the exit of a single thread LP. */
1097 exit_lwp (struct lwp_info
*lp
)
1099 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1103 if (print_thread_events
)
1104 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
1106 delete_thread (lp
->ptid
);
1109 delete_lwp (lp
->ptid
);
1112 /* Return an lwp's tgid, found in `/proc/PID/status'. */
1115 linux_proc_get_tgid (int lwpid
)
1121 snprintf (buf
, sizeof (buf
), "/proc/%d/status", (int) lwpid
);
1122 status_file
= fopen (buf
, "r");
1123 if (status_file
!= NULL
)
1125 while (fgets (buf
, sizeof (buf
), status_file
))
1127 if (strncmp (buf
, "Tgid:", 5) == 0)
1129 tgid
= strtoul (buf
+ strlen ("Tgid:"), NULL
, 10);
1134 fclose (status_file
);
1140 /* Detect `T (stopped)' in `/proc/PID/status'.
1141 Other states including `T (tracing stop)' are reported as false. */
1144 pid_is_stopped (pid_t pid
)
1150 snprintf (buf
, sizeof (buf
), "/proc/%d/status", (int) pid
);
1151 status_file
= fopen (buf
, "r");
1152 if (status_file
!= NULL
)
1156 while (fgets (buf
, sizeof (buf
), status_file
))
1158 if (strncmp (buf
, "State:", 6) == 0)
1164 if (have_state
&& strstr (buf
, "T (stopped)") != NULL
)
1166 fclose (status_file
);
1171 /* Wait for the LWP specified by LP, which we have just attached to.
1172 Returns a wait status for that LWP, to cache. */
1175 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
1178 pid_t new_pid
, pid
= GET_LWP (ptid
);
1181 if (pid_is_stopped (pid
))
1183 if (debug_linux_nat
)
1184 fprintf_unfiltered (gdb_stdlog
,
1185 "LNPAW: Attaching to a stopped process\n");
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.
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
);
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);
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
)
1214 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
1216 /* Try again with __WCLONE to check cloned processes. */
1217 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
1221 gdb_assert (pid
== new_pid
&& WIFSTOPPED (status
));
1223 if (WSTOPSIG (status
) != SIGSTOP
)
1226 if (debug_linux_nat
)
1227 fprintf_unfiltered (gdb_stdlog
,
1228 "LNPAW: Received %s after attaching\n",
1229 status_to_str (status
));
1235 /* Attach to the LWP specified by PID. Return 0 if successful or -1
1236 if the new LWP could not be attached. */
1239 lin_lwp_attach_lwp (ptid_t ptid
)
1241 struct lwp_info
*lp
;
1244 gdb_assert (is_lwp (ptid
));
1246 block_child_signals (&prev_mask
);
1248 lp
= find_lwp_pid (ptid
);
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
1256 if (GET_LWP (ptid
) != GET_PID (ptid
) && lp
== NULL
)
1258 int status
, cloned
= 0, signalled
= 0;
1260 if (ptrace (PTRACE_ATTACH
, GET_LWP (ptid
), 0, 0) < 0)
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
1267 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1268 safe_strerror (errno
));
1269 restore_child_signals_mask (&prev_mask
);
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
));
1278 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1279 lp
= add_lwp (ptid
);
1281 lp
->cloned
= cloned
;
1282 lp
->signalled
= signalled
;
1283 if (WSTOPSIG (status
) != SIGSTOP
)
1286 lp
->status
= status
;
1289 target_post_attach (GET_LWP (lp
->ptid
));
1291 if (debug_linux_nat
)
1293 fprintf_unfiltered (gdb_stdlog
,
1294 "LLAL: waitpid %s received %s\n",
1295 target_pid_to_str (ptid
),
1296 status_to_str (status
));
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. */
1308 lp
= add_lwp (ptid
);
1312 restore_child_signals_mask (&prev_mask
);
1317 linux_nat_create_inferior (struct target_ops
*ops
,
1318 char *exec_file
, char *allargs
, char **env
,
1321 #ifdef HAVE_PERSONALITY
1322 int personality_orig
= 0, personality_set
= 0;
1323 #endif /* HAVE_PERSONALITY */
1325 /* The fork_child mechanism is synchronous and calls target_wait, so
1326 we have to mask the async mode. */
1328 #ifdef HAVE_PERSONALITY
1329 if (disable_randomization
)
1332 personality_orig
= personality (0xffffffff);
1333 if (errno
== 0 && !(personality_orig
& ADDR_NO_RANDOMIZE
))
1335 personality_set
= 1;
1336 personality (personality_orig
| ADDR_NO_RANDOMIZE
);
1338 if (errno
!= 0 || (personality_set
1339 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE
)))
1340 warning (_("Error disabling address space randomization: %s"),
1341 safe_strerror (errno
));
1343 #endif /* HAVE_PERSONALITY */
1345 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1347 #ifdef HAVE_PERSONALITY
1348 if (personality_set
)
1351 personality (personality_orig
);
1353 warning (_("Error restoring address space randomization: %s"),
1354 safe_strerror (errno
));
1356 #endif /* HAVE_PERSONALITY */
1360 linux_nat_attach (struct target_ops
*ops
, char *args
, int from_tty
)
1362 struct lwp_info
*lp
;
1366 linux_ops
->to_attach (ops
, args
, from_tty
);
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
);
1373 /* Add the initial process as the first LWP to the list. */
1374 lp
= add_lwp (ptid
);
1376 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1380 /* Save the wait status to report later. */
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
));
1387 lp
->status
= status
;
1389 if (target_can_async_p ())
1390 target_async (inferior_event_handler
, 0);
1393 /* Get pending status of LP. */
1395 get_pending_status (struct lwp_info
*lp
, int *status
)
1397 struct target_waitstatus last
;
1400 get_last_target_status (&last_ptid
, &last
);
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). */
1411 enum target_signal signo
= TARGET_SIGNAL_0
;
1413 if (is_executing (lp
->ptid
))
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
1421 signo
= target_signal_from_host (WSTOPSIG (lp
->status
));
1425 /* If the core knows the thread is not executing, then we
1426 have the last signal recorded in
1427 thread_info->stop_signal. */
1429 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1430 signo
= tp
->stop_signal
;
1433 if (signo
!= TARGET_SIGNAL_0
1434 && !signal_pass_state (signo
))
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
));
1444 if (signo
!= TARGET_SIGNAL_0
)
1445 *status
= W_STOPCODE (target_signal_to_host (signo
));
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
));
1456 if (GET_LWP (lp
->ptid
) == GET_LWP (last_ptid
))
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
));
1464 *status
= lp
->status
;
1471 detach_callback (struct lwp_info
*lp
, void *data
)
1473 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
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
));
1480 /* If there is a pending SIGSTOP, get rid of it. */
1483 if (debug_linux_nat
)
1484 fprintf_unfiltered (gdb_stdlog
,
1485 "DC: Sending SIGCONT to %s\n",
1486 target_pid_to_str (lp
->ptid
));
1488 kill_lwp (GET_LWP (lp
->ptid
), SIGCONT
);
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
))
1498 /* Pass on any pending signal for this LWP. */
1499 get_pending_status (lp
, &status
);
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
));
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
)));
1513 delete_lwp (lp
->ptid
);
1520 linux_nat_detach (struct target_ops
*ops
, char *args
, int from_tty
)
1524 enum target_signal sig
;
1525 struct lwp_info
*main_lwp
;
1527 pid
= GET_PID (inferior_ptid
);
1529 if (target_can_async_p ())
1530 linux_nat_async (NULL
, 0);
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
);
1539 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1541 /* Only the initial process should be left right now. */
1542 gdb_assert (num_lwps (GET_PID (inferior_ptid
)) == 1);
1544 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
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
))
1551 /* Put the signal number in ARGS so that inf_ptrace_detach will
1552 pass it along with PTRACE_DETACH. */
1554 sprintf (args
, "%d", (int) WSTOPSIG (status
));
1555 fprintf_unfiltered (gdb_stdlog
,
1556 "LND: Sending signal %s to %s\n",
1558 target_pid_to_str (main_lwp
->ptid
));
1561 delete_lwp (main_lwp
->ptid
);
1563 if (forks_exist_p ())
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
1569 linux_fork_detach (args
, from_tty
);
1571 if (non_stop
&& target_can_async_p ())
1572 target_async (inferior_event_handler
, 0);
1575 linux_ops
->to_detach (ops
, args
, from_tty
);
1581 resume_callback (struct lwp_info
*lp
, void *data
)
1583 if (lp
->stopped
&& lp
->status
== 0)
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
));
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
));
1599 memset (&lp
->siginfo
, 0, sizeof (lp
->siginfo
));
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
));
1612 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1619 resume_set_callback (struct lwp_info
*lp
, void *data
)
1626 linux_nat_resume (struct target_ops
*ops
,
1627 ptid_t ptid
, int step
, enum target_signal signo
)
1630 struct lwp_info
*lp
;
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
));
1641 block_child_signals (&prev_mask
);
1643 /* A specific PTID means `step only this process id'. */
1644 resume_many
= (ptid_equal (minus_one_ptid
, ptid
)
1645 || ptid_is_pid (ptid
));
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
);
1654 iterate_over_lwps (minus_one_ptid
, resume_set_callback
, NULL
);
1656 /* See if it's the current inferior that should be handled
1659 lp
= find_lwp_pid (inferior_ptid
);
1661 lp
= find_lwp_pid (ptid
);
1662 gdb_assert (lp
!= NULL
);
1664 /* Remember if we're stepping. */
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. */
1675 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1678 struct inferior
*inf
;
1680 inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
1682 saved_signo
= target_signal_from_host (WSTOPSIG (lp
->status
));
1684 /* Defer to common code if we're gaining control of the
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)
1691 if (debug_linux_nat
)
1692 fprintf_unfiltered (gdb_stdlog
,
1693 "LLR: Not short circuiting for ignored "
1694 "status 0x%x\n", lp
->status
);
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
;
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
);
1710 if (debug_linux_nat
)
1711 fprintf_unfiltered (gdb_stdlog
,
1712 "LLR: Short circuiting for status 0x%x\n",
1715 restore_child_signals_mask (&prev_mask
);
1716 if (target_can_async_p ())
1718 target_async (inferior_event_handler
, 0);
1719 /* Tell the event loop we have something to process. */
1725 /* Mark LWP as not stopped to prevent it from being continued by
1730 iterate_over_lwps (ptid
, resume_callback
, NULL
);
1732 /* Convert to something the lower layer understands. */
1733 ptid
= pid_to_ptid (GET_LWP (lp
->ptid
));
1735 linux_ops
->to_resume (linux_ops
, ptid
, step
, signo
);
1736 memset (&lp
->siginfo
, 0, sizeof (lp
->siginfo
));
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");
1745 restore_child_signals_mask (&prev_mask
);
1746 if (target_can_async_p ())
1747 target_async (inferior_event_handler
, 0);
1750 /* Issue kill to specified lwp. */
1752 static int tkill_failed
;
1755 kill_lwp (int lwpid
, int signo
)
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. */
1762 #ifdef HAVE_TKILL_SYSCALL
1765 int ret
= syscall (__NR_tkill
, lwpid
, signo
);
1766 if (errno
!= ENOSYS
)
1773 return kill (lwpid
, signo
);
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. */
1783 linux_handle_extended_wait (struct lwp_info
*lp
, int status
,
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;
1791 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1792 || event
== PTRACE_EVENT_CLONE
)
1794 unsigned long new_pid
;
1797 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
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
))
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);
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
);
1816 ourstatus
->value
.related_pid
= ptid_build (new_pid
, new_pid
, 0);
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
;
1824 struct cleanup
*old_chain
;
1826 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
1827 new_lp
= add_lwp (BUILD_LWP (new_pid
, GET_PID (lp
->ptid
)));
1829 new_lp
->stopped
= 1;
1831 if (WSTOPSIG (status
) != SIGSTOP
)
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. */
1841 new_lp
->signalled
= 1;
1848 /* Add the new thread to GDB's lists as soon as possible
1851 1) the frontend doesn't have to wait for a stop to
1854 2) we tag it with the correct running state. */
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
))
1860 /* We're not using thread_db. Add it to GDB's
1862 target_post_attach (GET_LWP (new_lp
->ptid
));
1863 add_thread (new_lp
->ptid
);
1868 set_running (new_lp
->ptid
, 1);
1869 set_executing (new_lp
->ptid
, 1);
1875 new_lp
->stopped
= 0;
1876 new_lp
->resumed
= 1;
1877 ptrace (PTRACE_CONT
, new_pid
, 0,
1878 status
? WSTOPSIG (status
) : 0);
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);
1893 if (event
== PTRACE_EVENT_EXEC
)
1895 if (debug_linux_nat
)
1896 fprintf_unfiltered (gdb_stdlog
,
1897 "LHEW: Got exec event from LWP %ld\n",
1898 GET_LWP (lp
->ptid
));
1900 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
1901 ourstatus
->value
.execd_pathname
1902 = xstrdup (linux_child_pid_to_exec_file (pid
));
1904 if (linux_parent_pid
)
1906 detach_breakpoints (linux_parent_pid
);
1907 ptrace (PTRACE_DETACH
, linux_parent_pid
, 0, 0);
1909 linux_parent_pid
= 0;
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.
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 ();
1925 internal_error (__FILE__
, __LINE__
,
1926 _("unknown ptrace event %d"), event
);
1929 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
1933 wait_lwp (struct lwp_info
*lp
)
1937 int thread_dead
= 0;
1939 gdb_assert (!lp
->stopped
);
1940 gdb_assert (lp
->status
== 0);
1942 pid
= my_waitpid (GET_LWP (lp
->ptid
), &status
, 0);
1943 if (pid
== -1 && errno
== ECHILD
)
1945 pid
= my_waitpid (GET_LWP (lp
->ptid
), &status
, __WCLONE
);
1946 if (pid
== -1 && errno
== ECHILD
)
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. */
1954 if (debug_linux_nat
)
1955 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
1956 target_pid_to_str (lp
->ptid
));
1962 gdb_assert (pid
== GET_LWP (lp
->ptid
));
1964 if (debug_linux_nat
)
1966 fprintf_unfiltered (gdb_stdlog
,
1967 "WL: waitpid %s received %s\n",
1968 target_pid_to_str (lp
->ptid
),
1969 status_to_str (status
));
1973 /* Check if the thread has exited. */
1974 if (WIFEXITED (status
) || WIFSIGNALED (status
))
1977 if (debug_linux_nat
)
1978 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
1979 target_pid_to_str (lp
->ptid
));
1988 gdb_assert (WIFSTOPPED (status
));
1990 /* Handle GNU/Linux's extended waitstatus for trace events. */
1991 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
1993 if (debug_linux_nat
)
1994 fprintf_unfiltered (gdb_stdlog
,
1995 "WL: Handling extended status 0x%06x\n",
1997 if (linux_handle_extended_wait (lp
, status
, 1))
1998 return wait_lwp (lp
);
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. */
2010 save_siginfo (struct lwp_info
*lp
)
2013 ptrace (PTRACE_GETSIGINFO
, GET_LWP (lp
->ptid
),
2014 (PTRACE_TYPE_ARG3
) 0, &lp
->siginfo
);
2017 memset (&lp
->siginfo
, 0, sizeof (lp
->siginfo
));
2020 /* Send a SIGSTOP to LP. */
2023 stop_callback (struct lwp_info
*lp
, void *data
)
2025 if (!lp
->stopped
&& !lp
->signalled
)
2029 if (debug_linux_nat
)
2031 fprintf_unfiltered (gdb_stdlog
,
2032 "SC: kill %s **<SIGSTOP>**\n",
2033 target_pid_to_str (lp
->ptid
));
2036 ret
= kill_lwp (GET_LWP (lp
->ptid
), SIGSTOP
);
2037 if (debug_linux_nat
)
2039 fprintf_unfiltered (gdb_stdlog
,
2040 "SC: lwp kill %d %s\n",
2042 errno
? safe_strerror (errno
) : "ERRNO-OK");
2046 gdb_assert (lp
->status
== 0);
2052 /* Return non-zero if LWP PID has a pending SIGINT. */
2055 linux_nat_has_pending_sigint (int pid
)
2057 sigset_t pending
, blocked
, ignored
;
2060 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2062 if (sigismember (&pending
, SIGINT
)
2063 && !sigismember (&ignored
, SIGINT
))
2069 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2072 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
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
)
2080 lp
->ignore_sigint
= 1;
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. */
2092 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2094 if (!lp
->ignore_sigint
)
2097 if (!linux_nat_has_pending_sigint (GET_LWP (lp
->ptid
)))
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;
2107 /* Wait until LP is stopped. */
2110 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2116 status
= wait_lwp (lp
);
2120 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2121 && WSTOPSIG (status
) == SIGINT
)
2123 lp
->ignore_sigint
= 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");
2133 return stop_wait_callback (lp
, NULL
);
2136 maybe_clear_ignore_sigint (lp
);
2138 if (WSTOPSIG (status
) != SIGSTOP
)
2140 if (WSTOPSIG (status
) == SIGTRAP
)
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
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. */
2155 /* Save the trap's siginfo in case we need it later. */
2158 /* Now resume this LWP and get the SIGSTOP event. */
2160 ptrace (PTRACE_CONT
, GET_LWP (lp
->ptid
), 0, 0);
2161 if (debug_linux_nat
)
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");
2168 fprintf_unfiltered (gdb_stdlog
,
2169 "SWC: Candidate SIGTRAP event in %s\n",
2170 target_pid_to_str (lp
->ptid
));
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
);
2176 /* Hold the SIGTRAP for handling by linux_nat_wait. If
2177 there's another event, throw it back into the
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
));
2189 /* Save the sigtrap event. */
2190 lp
->status
= status
;
2195 /* The thread was stopped with a signal other than
2196 SIGSTOP, and didn't accidentally trip a breakpoint. */
2198 if (debug_linux_nat
)
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
));
2205 /* Now resume this LWP and get the SIGSTOP event. */
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");
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
);
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. */
2223 if (debug_linux_nat
)
2225 fprintf_unfiltered (gdb_stdlog
,
2226 "SWC: kill %s, %s\n",
2227 target_pid_to_str (lp
->ptid
),
2228 status_to_str ((int) status
));
2230 kill_lwp (GET_LWP (lp
->ptid
), WSTOPSIG (status
));
2233 lp
->status
= status
;
2239 /* We caught the SIGSTOP that we intended to catch, so
2240 there's no SIGSTOP pending. */
2249 /* Return non-zero if LP has a wait status pending. */
2252 status_callback (struct lwp_info
*lp
, void *data
)
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
)
2264 /* Return non-zero if LP isn't stopped. */
2267 running_callback (struct lwp_info
*lp
, void *data
)
2269 return (lp
->stopped
== 0 || (lp
->status
!= 0 && lp
->resumed
));
2272 /* Count the LWP's that have had events. */
2275 count_events_callback (struct lwp_info
*lp
, void *data
)
2279 gdb_assert (count
!= NULL
);
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
)
2289 /* Select the LWP (if any) that is currently being single-stepped. */
2292 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2294 if (lp
->step
&& lp
->status
!= 0)
2300 /* Select the Nth LWP that has had a SIGTRAP event. */
2303 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2305 int *selector
= data
;
2307 gdb_assert (selector
!= NULL
);
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)
2319 cancel_breakpoint (struct lwp_info
*lp
)
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.
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
2330 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2331 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2334 pc
= regcache_read_pc (regcache
) - gdbarch_decr_pc_after_break (gdbarch
);
2335 if (breakpoint_inserted_here_p (pc
))
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
));
2342 /* Back up the PC if necessary. */
2343 if (gdbarch_decr_pc_after_break (gdbarch
))
2344 regcache_write_pc (regcache
, pc
);
2352 cancel_breakpoints_callback (struct lwp_info
*lp
, void *data
)
2354 struct lwp_info
*event_lp
= data
;
2356 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
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.
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
2372 && WIFSTOPPED (lp
->status
) && WSTOPSIG (lp
->status
) == SIGTRAP
2373 && cancel_breakpoint (lp
))
2374 /* Throw away the SIGTRAP. */
2380 /* Select one LWP out of those that have events pending. */
2383 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2386 int random_selector
;
2387 struct lwp_info
*event_lp
;
2389 /* Record the wait status for the original LWP. */
2390 (*orig_lp
)->status
= *status
;
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
)
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
));
2404 /* No single-stepping LWP. Select one at random, out of those
2405 which have had SIGTRAP events. */
2407 /* First see how many SIGTRAP events we have. */
2408 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
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));
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
);
2419 event_lp
= iterate_over_lwps (filter
,
2420 select_event_lwp_callback
,
2424 if (event_lp
!= NULL
)
2426 /* Switch the event LWP. */
2427 *orig_lp
= event_lp
;
2428 *status
= event_lp
->status
;
2431 /* Flush the wait status for the event LWP. */
2432 (*orig_lp
)->status
= 0;
2435 /* Return non-zero if LP has been resumed. */
2438 resumed_callback (struct lwp_info
*lp
, void *data
)
2443 /* Stop an active thread, verify it still exists, then resume it. */
2446 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2448 struct lwp_info
*ptr
;
2450 if (!lp
->stopped
&& !lp
->signalled
)
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
)
2458 resume_callback (lp
, NULL
);
2459 resume_set_callback (lp
, NULL
);
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
)
2470 struct lwp_info
*lp
;
2472 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2474 /* Check for stop events reported by a process we didn't already
2475 know about - anything not already in our LWP list.
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
)
2484 linux_record_stopped_pid (lwpid
, status
);
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
2492 if (!WIFSTOPPED (status
) && !lp
)
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. */
2504 lp
= add_lwp (BUILD_LWP (lwpid
, GET_PID (inferior_ptid
)));
2505 if (options
& __WCLONE
)
2508 gdb_assert (WIFSTOPPED (status
)
2509 && WSTOPSIG (status
) == SIGSTOP
);
2512 if (!in_thread_list (inferior_ptid
))
2514 inferior_ptid
= BUILD_LWP (GET_PID (inferior_ptid
),
2515 GET_PID (inferior_ptid
));
2516 add_thread (inferior_ptid
);
2519 add_thread (lp
->ptid
);
2522 /* Save the trap's siginfo in case we need it later. */
2523 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
)
2526 /* Handle GNU/Linux's extended waitstatus for trace events. */
2527 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2529 if (debug_linux_nat
)
2530 fprintf_unfiltered (gdb_stdlog
,
2531 "LLW: Handling extended status 0x%06x\n",
2533 if (linux_handle_extended_wait (lp
, status
, 0))
2537 /* Check if the thread has exited. */
2538 if ((WIFEXITED (status
) || WIFSIGNALED (status
))
2539 && num_lwps (GET_PID (lp
->ptid
)) > 1)
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
2551 if (GET_PID (lp
->ptid
) == GET_LWP (lp
->ptid
))
2554 iterate_over_lwps (pid_to_ptid (GET_PID (lp
->ptid
)),
2555 stop_and_resume_callback
, NULL
);
2558 if (debug_linux_nat
)
2559 fprintf_unfiltered (gdb_stdlog
,
2560 "LLW: %s exited.\n",
2561 target_pid_to_str (lp
->ptid
));
2563 if (num_lwps (GET_PID (lp
->ptid
)) > 1)
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
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
))
2579 ptid_t ptid
= pid_to_ptid (GET_PID (lp
->ptid
));
2581 if (debug_linux_nat
)
2582 fprintf_unfiltered (gdb_stdlog
,
2583 "LLW: %s exited.\n",
2584 target_pid_to_str (lp
->ptid
));
2588 /* Make sure there is at least one thread running. */
2589 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
2591 /* Discard the event. */
2595 /* Make sure we don't report a SIGSTOP that we sent ourselves in
2596 an attempt to stop an LWP. */
2598 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
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
));
2605 /* This is a delayed SIGSTOP. */
2608 registers_changed ();
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",
2616 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2617 target_pid_to_str (lp
->ptid
));
2620 gdb_assert (lp
->resumed
);
2622 /* Discard the event. */
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
)
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
));
2636 /* This is a delayed SIGINT. */
2637 lp
->ignore_sigint
= 0;
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",
2646 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2647 target_pid_to_str (lp
->ptid
));
2650 gdb_assert (lp
->resumed
);
2652 /* Discard the event. */
2656 /* An interesting event. */
2662 linux_nat_wait_1 (struct target_ops
*ops
,
2663 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
2666 static sigset_t prev_mask
;
2667 struct lwp_info
*lp
= NULL
;
2672 if (debug_linux_nat_async
)
2673 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
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
))
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
)));
2685 lp
= add_lwp (inferior_ptid
);
2689 /* Make sure SIGCHLD is blocked. */
2690 block_child_signals (&prev_mask
);
2692 if (ptid_equal (ptid
, minus_one_ptid
))
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. */
2701 pid
= GET_LWP (ptid
);
2707 /* Make sure there is at least one LWP that has been resumed. */
2708 gdb_assert (iterate_over_lwps (ptid
, resumed_callback
, NULL
));
2710 /* First check if there is a LWP with a wait status pending. */
2713 /* Any LWP that's been resumed will do. */
2714 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
2717 status
= lp
->status
;
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
));
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
2730 options
= __WCLONE
| WNOHANG
;
2732 else if (is_lwp (ptid
))
2734 if (debug_linux_nat
)
2735 fprintf_unfiltered (gdb_stdlog
,
2736 "LLW: Waiting for specific LWP %s.\n",
2737 target_pid_to_str (ptid
));
2739 /* We have a specific LWP to check. */
2740 lp
= find_lwp_pid (ptid
);
2742 status
= lp
->status
;
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
));
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
);
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
)
2765 if (lp
&& lp
->signalled
)
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. */
2776 /* Resume the thread. It should halt immediately returning the
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
));
2787 gdb_assert (lp
->resumed
);
2789 /* This should catch the pending SIGSTOP. */
2790 stop_wait_callback (lp
, NULL
);
2793 if (!target_can_async_p ())
2795 /* Causes SIGINT to be passed on to the attached process. */
2799 /* Translate generic target_wait options into waitpid options. */
2800 if (target_options
& TARGET_WNOHANG
)
2807 lwpid
= my_waitpid (pid
, &status
, options
);
2811 gdb_assert (pid
== -1 || lwpid
== pid
);
2813 if (debug_linux_nat
)
2815 fprintf_unfiltered (gdb_stdlog
,
2816 "LLW: waitpid %ld received %s\n",
2817 (long) lwpid
, status_to_str (status
));
2820 lp
= linux_nat_filter_event (lwpid
, status
, options
);
2823 && ptid_is_pid (ptid
)
2824 && ptid_get_pid (lp
->ptid
) != ptid_get_pid (ptid
))
2826 if (debug_linux_nat
)
2827 fprintf (stderr
, "LWP %ld got an event %06x, leaving pending.\n",
2828 ptid_get_lwp (lp
->ptid
), status
);
2830 if (WIFSTOPPED (status
))
2832 if (WSTOPSIG (status
) != SIGSTOP
)
2834 lp
->status
= status
;
2836 stop_callback (lp
, NULL
);
2838 /* Resume in order to collect the sigstop. */
2839 ptrace (PTRACE_CONT
, GET_LWP (lp
->ptid
), 0, 0);
2841 stop_wait_callback (lp
, NULL
);
2849 else if (WIFEXITED (status
) || WIFSIGNALED (status
))
2851 if (debug_linux_nat
)
2852 fprintf (stderr
, "Process %ld exited while stopping LWPs\n",
2853 ptid_get_lwp (lp
->ptid
));
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
2862 lp
->status
= status
;
2864 /* Prevent trying to stop this thread again. We'll
2865 never try to resume it because it has a pending
2869 /* Dead LWP's aren't expected to reported a pending
2873 /* Store the pending event in the waitstatus as
2874 well, because W_EXITCODE(0,0) == 0. */
2875 store_waitstatus (&lp
->waitstatus
, status
);
2889 /* waitpid did return something. Restart over. */
2890 options
|= __WCLONE
;
2898 /* Alternate between checking cloned and uncloned processes. */
2899 options
^= __WCLONE
;
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
)
2906 if (target_options
& TARGET_WNOHANG
)
2908 /* No interesting event. */
2909 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2911 if (debug_linux_nat_async
)
2912 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
2914 restore_child_signals_mask (&prev_mask
);
2915 return minus_one_ptid
;
2918 sigsuspend (&suspend_mask
);
2922 /* We shouldn't end up here unless we want to try again. */
2923 gdb_assert (lp
== NULL
);
2926 if (!target_can_async_p ())
2927 clear_sigint_trap ();
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
2938 if (WIFSTOPPED (status
))
2940 int signo
= target_signal_from_host (WSTOPSIG (status
));
2941 struct inferior
*inf
;
2943 inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
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
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)
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
)),
2964 if (debug_linux_nat
)
2965 fprintf_unfiltered (gdb_stdlog
,
2966 "LLW: %s %s, %s (preempt 'handle')\n",
2968 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2969 target_pid_to_str (lp
->ptid
),
2970 signo
? strsignal (signo
) : "0");
2977 /* Only do the below in all-stop, as we currently use SIGINT
2978 to implement target_stop (see linux_nat_stop) in
2980 if (signo
== TARGET_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
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;
2992 maybe_clear_ignore_sigint (lp
);
2996 /* This LWP is stopped now. */
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
));
3005 /* Now stop all other LWP's ... */
3006 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
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
);
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
3017 select_event_lwp (ptid
, &lp
, &status
);
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
);
3025 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
)
3027 if (debug_linux_nat
)
3028 fprintf_unfiltered (gdb_stdlog
,
3029 "LLW: trap ptid is %s.\n",
3030 target_pid_to_str (lp
->ptid
));
3033 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3035 *ourstatus
= lp
->waitstatus
;
3036 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3039 store_waitstatus (ourstatus
, status
);
3041 if (debug_linux_nat_async
)
3042 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3044 restore_child_signals_mask (&prev_mask
);
3049 linux_nat_wait (struct target_ops
*ops
,
3050 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3055 if (debug_linux_nat
)
3056 fprintf_unfiltered (gdb_stdlog
, "linux_nat_wait: [%s]\n", target_pid_to_str (ptid
));
3058 /* Flush the async file first. */
3059 if (target_can_async_p ())
3060 async_file_flush ();
3062 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
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
)))
3072 /* Get ready for the next event. */
3073 if (target_can_async_p ())
3074 target_async (inferior_event_handler
, 0);
3080 kill_callback (struct lwp_info
*lp
, void *data
)
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");
3094 kill_wait_callback (struct lwp_info
*lp
, void *data
)
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. */
3102 /* For cloned processes we must check both with __WCLONE and
3103 without, since the exit status of a cloned process isn't reported
3109 pid
= my_waitpid (GET_LWP (lp
->ptid
), NULL
, __WCLONE
);
3110 if (pid
!= (pid_t
) -1)
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
3121 kill_callback (lp
, NULL
);
3124 while (pid
== GET_LWP (lp
->ptid
));
3126 gdb_assert (pid
== -1 && errno
== ECHILD
);
3131 pid
= my_waitpid (GET_LWP (lp
->ptid
), NULL
, 0);
3132 if (pid
!= (pid_t
) -1)
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
);
3142 while (pid
== GET_LWP (lp
->ptid
));
3144 gdb_assert (pid
== -1 && errno
== ECHILD
);
3149 linux_nat_kill (struct target_ops
*ops
)
3151 struct target_waitstatus last
;
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. */
3159 get_last_target_status (&last_ptid
, &last
);
3161 if (last
.kind
== TARGET_WAITKIND_FORKED
3162 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3164 ptrace (PT_KILL
, PIDGET (last
.value
.related_pid
), 0, 0);
3168 if (forks_exist_p ())
3169 linux_fork_killall ();
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
);
3180 /* Kill all LWP's ... */
3181 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3183 /* ... and wait until we've flushed all events. */
3184 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3187 target_mourn_inferior ();
3191 linux_nat_mourn_inferior (struct target_ops
*ops
)
3193 purge_lwp_list (ptid_get_pid (inferior_ptid
));
3195 if (! forks_exist_p ())
3196 /* Normal case, no other forks available. */
3197 linux_ops
->to_mourn_inferior (ops
);
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 ();
3205 /* Convert a native/host siginfo object, into/from the siginfo in the
3206 layout of the inferiors' architecture. */
3209 siginfo_fixup (struct siginfo
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3213 if (linux_nat_siginfo_fixup
!= NULL
)
3214 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3216 /* If there was no callback, or the callback didn't do anything,
3217 then just do a straight memcpy. */
3221 memcpy (siginfo
, inf_siginfo
, sizeof (struct siginfo
));
3223 memcpy (inf_siginfo
, siginfo
, sizeof (struct siginfo
));
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
)
3233 struct siginfo siginfo
;
3234 gdb_byte inf_siginfo
[sizeof (struct siginfo
)];
3236 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3237 gdb_assert (readbuf
|| writebuf
);
3239 pid
= GET_LWP (inferior_ptid
);
3241 pid
= GET_PID (inferior_ptid
);
3243 if (offset
> sizeof (siginfo
))
3247 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
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
3257 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3259 if (offset
+ len
> sizeof (siginfo
))
3260 len
= sizeof (siginfo
) - offset
;
3262 if (readbuf
!= NULL
)
3263 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3266 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3268 /* Convert back to ptrace layout before flushing it out. */
3269 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3272 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
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
)
3286 struct cleanup
*old_chain
;
3289 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3290 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3293 /* The target is connected but no live inferior is selected. Pass
3294 this request down to a lower stratum (e.g., the executable
3296 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3299 old_chain
= save_inferior_ptid ();
3301 if (is_lwp (inferior_ptid
))
3302 inferior_ptid
= pid_to_ptid (GET_LWP (inferior_ptid
));
3304 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3307 do_cleanups (old_chain
);
3312 linux_thread_alive (ptid_t ptid
)
3316 gdb_assert (is_lwp (ptid
));
3318 /* Send signal 0 instead of anything ptrace, because ptracing a
3319 running thread errors out claiming that the thread doesn't
3321 err
= kill_lwp (GET_LWP (ptid
), 0);
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");
3336 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3338 return linux_thread_alive (ptid
);
3342 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3344 static char buf
[64];
3347 && (GET_PID (ptid
) != GET_LWP (ptid
)
3348 || num_lwps (GET_PID (ptid
)) > 1))
3350 snprintf (buf
, sizeof (buf
), "LWP %ld", GET_LWP (ptid
));
3354 return normal_pid_to_str (ptid
);
3357 /* Accepts an integer PID; Returns a string representing a file that
3358 can be opened to get the symbols for the child process. */
3361 linux_child_pid_to_exec_file (int pid
)
3363 char *name1
, *name2
;
3365 name1
= xmalloc (MAXPATHLEN
);
3366 name2
= xmalloc (MAXPATHLEN
);
3367 make_cleanup (xfree
, name1
);
3368 make_cleanup (xfree
, name2
);
3369 memset (name2
, 0, MAXPATHLEN
);
3371 sprintf (name1
, "/proc/%d/exe", pid
);
3372 if (readlink (name1
, name2
, MAXPATHLEN
) > 0)
3378 /* Service function for corefiles and info proc. */
3381 read_mapping (FILE *mapfile
,
3386 char *device
, long long *inode
, char *filename
)
3388 int ret
= fscanf (mapfile
, "%llx-%llx %s %llx %s %llx",
3389 addr
, endaddr
, permissions
, offset
, device
, inode
);
3392 if (ret
> 0 && ret
!= EOF
)
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.
3399 Note the filename is used for informational purposes
3401 ret
+= fscanf (mapfile
, "%[^\n]\n", filename
);
3404 return (ret
!= 0 && ret
!= EOF
);
3407 /* Fills the "to_find_memory_regions" target vector. Lists the memory
3408 regions in the inferior for a corefile. */
3411 linux_nat_find_memory_regions (int (*func
) (CORE_ADDR
,
3413 int, int, int, void *), void *obfd
)
3415 int pid
= PIDGET (inferior_ptid
);
3416 char mapsfilename
[MAXPATHLEN
];
3418 long long addr
, endaddr
, size
, offset
, inode
;
3419 char permissions
[8], device
[8], filename
[MAXPATHLEN
];
3420 int read
, write
, exec
;
3422 struct cleanup
*cleanup
;
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
);
3431 fprintf_filtered (gdb_stdout
,
3432 "Reading memory regions from %s\n", mapsfilename
);
3434 /* Now iterate until end-of-file. */
3435 while (read_mapping (mapsfile
, &addr
, &endaddr
, &permissions
[0],
3436 &offset
, &device
[0], &inode
, &filename
[0]))
3438 size
= endaddr
- addr
;
3440 /* Get the segment's permissions. */
3441 read
= (strchr (permissions
, 'r') != 0);
3442 write
= (strchr (permissions
, 'w') != 0);
3443 exec
= (strchr (permissions
, 'x') != 0);
3447 fprintf_filtered (gdb_stdout
,
3448 "Save segment, %lld bytes at 0x%s (%c%c%c)",
3449 size
, paddr_nz (addr
),
3451 write
? 'w' : ' ', exec
? 'x' : ' ');
3453 fprintf_filtered (gdb_stdout
, " for %s", filename
);
3454 fprintf_filtered (gdb_stdout
, "\n");
3457 /* Invoke the callback function to create the corefile
3459 func (addr
, size
, read
, write
, exec
, obfd
);
3461 do_cleanups (cleanup
);
3466 find_signalled_thread (struct thread_info
*info
, void *data
)
3468 if (info
->stop_signal
!= TARGET_SIGNAL_0
3469 && ptid_get_pid (info
->ptid
) == ptid_get_pid (inferior_ptid
))
3475 static enum target_signal
3476 find_stop_signal (void)
3478 struct thread_info
*info
=
3479 iterate_over_threads (find_signalled_thread
, NULL
);
3482 return info
->stop_signal
;
3484 return TARGET_SIGNAL_0
;
3487 /* Records the thread's register state for the corefile note
3491 linux_nat_do_thread_registers (bfd
*obfd
, ptid_t ptid
,
3492 char *note_data
, int *note_size
,
3493 enum target_signal stop_signal
)
3495 gdb_gregset_t gregs
;
3496 gdb_fpregset_t fpregs
;
3497 unsigned long lwp
= ptid_get_lwp (ptid
);
3498 struct gdbarch
*gdbarch
= target_gdbarch
;
3499 struct regcache
*regcache
= get_thread_arch_regcache (ptid
, gdbarch
);
3500 const struct regset
*regset
;
3502 struct cleanup
*old_chain
;
3503 struct core_regset_section
*sect_list
;
3506 old_chain
= save_inferior_ptid ();
3507 inferior_ptid
= ptid
;
3508 target_fetch_registers (regcache
, -1);
3509 do_cleanups (old_chain
);
3511 core_regset_p
= gdbarch_regset_from_core_section_p (gdbarch
);
3512 sect_list
= gdbarch_core_regset_sections (gdbarch
);
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
));
3521 fill_gregset (regcache
, &gregs
, -1);
3523 note_data
= (char *) elfcore_write_prstatus (obfd
,
3527 stop_signal
, &gregs
);
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
)
3536 /* .reg was already handled above. */
3537 if (strcmp (sect_list
->sect_name
, ".reg") == 0)
3542 regset
= gdbarch_regset_from_core_section (gdbarch
,
3543 sect_list
->sect_name
,
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
,
3552 sect_list
->sect_name
,
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. */
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
));
3571 fill_fpregset (regcache
, &fpregs
, -1);
3573 note_data
= (char *) elfcore_write_prfpreg (obfd
,
3576 &fpregs
, sizeof (fpregs
));
3582 struct linux_nat_corefile_thread_data
3588 enum target_signal stop_signal
;
3591 /* Called by gdbthread.c once per thread. Records the thread's
3592 register state for the corefile note section. */
3595 linux_nat_corefile_thread_callback (struct lwp_info
*ti
, void *data
)
3597 struct linux_nat_corefile_thread_data
*args
= data
;
3599 args
->note_data
= linux_nat_do_thread_registers (args
->obfd
,
3609 /* Fills the "to_make_corefile_note" target vector. Builds the note
3610 section for a corefile, and returns it in a malloc buffer. */
3613 linux_nat_make_corefile_notes (bfd
*obfd
, int *note_size
)
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
));
3627 if (get_exec_file (0))
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 ())
3634 char *psargs_end
= psargs
+ sizeof (psargs
);
3636 /* linux_elfcore_write_prpsinfo () handles zero unterminated
3638 string_end
= memchr (psargs
, 0, sizeof (psargs
));
3639 if (string_end
!= NULL
)
3641 *string_end
++ = ' ';
3642 strncpy (string_end
, get_inferior_args (),
3643 psargs_end
- string_end
);
3646 note_data
= (char *) elfcore_write_prpsinfo (obfd
,
3648 note_size
, fname
, psargs
);
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
;
3661 auxv_len
= target_read_alloc (¤t_target
, TARGET_OBJECT_AUXV
,
3665 note_data
= elfcore_write_note (obfd
, note_data
, note_size
,
3666 "CORE", NT_AUXV
, auxv
, auxv_len
);
3670 make_cleanup (xfree
, note_data
);
3674 /* Implement the "info proc" command. */
3677 linux_nat_info_proc_cmd (char *args
, int from_tty
)
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
);
3684 char buffer
[MAXPATHLEN
];
3685 char fname1
[MAXPATHLEN
], fname2
[MAXPATHLEN
];
3698 /* Break up 'args' into an argv array. */
3699 argv
= gdb_buildargv (args
);
3700 make_cleanup_freeargv (argv
);
3702 while (argv
!= NULL
&& *argv
!= NULL
)
3704 if (isdigit (argv
[0][0]))
3706 pid
= strtoul (argv
[0], NULL
, 10);
3708 else if (strncmp (argv
[0], "mappings", strlen (argv
[0])) == 0)
3712 else if (strcmp (argv
[0], "status") == 0)
3716 else if (strcmp (argv
[0], "stat") == 0)
3720 else if (strcmp (argv
[0], "cmd") == 0)
3724 else if (strncmp (argv
[0], "exe", strlen (argv
[0])) == 0)
3728 else if (strcmp (argv
[0], "cwd") == 0)
3732 else if (strncmp (argv
[0], "all", strlen (argv
[0])) == 0)
3738 /* [...] (future options here) */
3743 error (_("No current process: you must name one."));
3745 sprintf (fname1
, "/proc/%ld", pid
);
3746 if (stat (fname1
, &dummy
) != 0)
3747 error (_("No /proc directory: '%s'"), fname1
);
3749 printf_filtered (_("process %ld\n"), pid
);
3750 if (cmdline_f
|| all
)
3752 sprintf (fname1
, "/proc/%ld/cmdline", pid
);
3753 if ((procfile
= fopen (fname1
, "r")) != NULL
)
3755 struct cleanup
*cleanup
= make_cleanup_fclose (procfile
);
3756 if (fgets (buffer
, sizeof (buffer
), procfile
))
3757 printf_filtered ("cmdline = '%s'\n", buffer
);
3759 warning (_("unable to read '%s'"), fname1
);
3760 do_cleanups (cleanup
);
3763 warning (_("unable to open /proc file '%s'"), fname1
);
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
);
3772 warning (_("unable to read link '%s'"), fname1
);
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
);
3781 warning (_("unable to read link '%s'"), fname1
);
3783 if (mappings_f
|| all
)
3785 sprintf (fname1
, "/proc/%ld/maps", pid
);
3786 if ((procfile
= fopen (fname1
, "r")) != NULL
)
3788 long long addr
, endaddr
, size
, offset
, inode
;
3789 char permissions
[8], device
[8], filename
[MAXPATHLEN
];
3790 struct cleanup
*cleanup
;
3792 cleanup
= make_cleanup_fclose (procfile
);
3793 printf_filtered (_("Mapped address spaces:\n\n"));
3794 if (gdbarch_addr_bit (target_gdbarch
) == 32)
3796 printf_filtered ("\t%10s %10s %10s %10s %7s\n",
3799 " Size", " Offset", "objfile");
3803 printf_filtered (" %18s %18s %10s %10s %7s\n",
3806 " Size", " Offset", "objfile");
3809 while (read_mapping (procfile
, &addr
, &endaddr
, &permissions
[0],
3810 &offset
, &device
[0], &inode
, &filename
[0]))
3812 size
= endaddr
- addr
;
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. */
3820 if (gdbarch_addr_bit (target_gdbarch
) == 32)
3822 printf_filtered ("\t%#10lx %#10lx %#10x %#10x %7s\n",
3823 (unsigned long) addr
, /* FIXME: pr_addr */
3824 (unsigned long) endaddr
,
3826 (unsigned int) offset
,
3827 filename
[0] ? filename
: "");
3831 printf_filtered (" %#18lx %#18lx %#10x %#10x %7s\n",
3832 (unsigned long) addr
, /* FIXME: pr_addr */
3833 (unsigned long) endaddr
,
3835 (unsigned int) offset
,
3836 filename
[0] ? filename
: "");
3840 do_cleanups (cleanup
);
3843 warning (_("unable to open /proc file '%s'"), fname1
);
3845 if (status_f
|| all
)
3847 sprintf (fname1
, "/proc/%ld/status", pid
);
3848 if ((procfile
= fopen (fname1
, "r")) != NULL
)
3850 struct cleanup
*cleanup
= make_cleanup_fclose (procfile
);
3851 while (fgets (buffer
, sizeof (buffer
), procfile
) != NULL
)
3852 puts_filtered (buffer
);
3853 do_cleanups (cleanup
);
3856 warning (_("unable to open /proc file '%s'"), fname1
);
3860 sprintf (fname1
, "/proc/%ld/stat", pid
);
3861 if ((procfile
= fopen (fname1
, "r")) != NULL
)
3866 struct cleanup
*cleanup
= make_cleanup_fclose (procfile
);
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 ", <mp
) > 0)
3885 printf_filtered (_("Flags: 0x%lx\n"), ltmp
);
3886 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3887 printf_filtered (_("Minor faults (no memory page): %lu\n"),
3888 (unsigned long) ltmp
);
3889 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3890 printf_filtered (_("Minor faults, children: %lu\n"),
3891 (unsigned long) ltmp
);
3892 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3893 printf_filtered (_("Major faults (memory page faults): %lu\n"),
3894 (unsigned long) ltmp
);
3895 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3896 printf_filtered (_("Major faults, children: %lu\n"),
3897 (unsigned long) ltmp
);
3898 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3899 printf_filtered (_("utime: %ld\n"), ltmp
);
3900 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3901 printf_filtered (_("stime: %ld\n"), ltmp
);
3902 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3903 printf_filtered (_("utime, children: %ld\n"), ltmp
);
3904 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3905 printf_filtered (_("stime, children: %ld\n"), ltmp
);
3906 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3907 printf_filtered (_("jiffies remaining in current time slice: %ld\n"),
3909 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3910 printf_filtered (_("'nice' value: %ld\n"), ltmp
);
3911 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3912 printf_filtered (_("jiffies until next timeout: %lu\n"),
3913 (unsigned long) ltmp
);
3914 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3915 printf_filtered (_("jiffies until next SIGALRM: %lu\n"),
3916 (unsigned long) ltmp
);
3917 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3918 printf_filtered (_("start time (jiffies since system boot): %ld\n"),
3920 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3921 printf_filtered (_("Virtual memory size: %lu\n"),
3922 (unsigned long) ltmp
);
3923 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3924 printf_filtered (_("Resident set size: %lu\n"), (unsigned long) ltmp
);
3925 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3926 printf_filtered (_("rlim: %lu\n"), (unsigned long) ltmp
);
3927 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3928 printf_filtered (_("Start of text: 0x%lx\n"), ltmp
);
3929 if (fscanf (procfile
, "%lu ", <mp
) > 0)
3930 printf_filtered (_("End of text: 0x%lx\n"), ltmp
);
3931 if (fscanf (procfile
, "%lu ", <mp
) > 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 ", <mp
) > 0) /* FIXME arch? */
3936 printf_filtered (_("Kernel stack pointer: 0x%lx\n"), ltmp
);
3937 if (fscanf (procfile
, "%lu ", <mp
) > 0) /* FIXME arch? */
3938 printf_filtered (_("Kernel instr pointer: 0x%lx\n"), ltmp
);
3939 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3940 printf_filtered (_("Pending signals bitmap: 0x%lx\n"), ltmp
);
3941 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3942 printf_filtered (_("Blocked signals bitmap: 0x%lx\n"), ltmp
);
3943 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3944 printf_filtered (_("Ignored signals bitmap: 0x%lx\n"), ltmp
);
3945 if (fscanf (procfile
, "%ld ", <mp
) > 0)
3946 printf_filtered (_("Catched signals bitmap: 0x%lx\n"), ltmp
);
3947 if (fscanf (procfile
, "%lu ", <mp
) > 0) /* FIXME arch? */
3948 printf_filtered (_("wchan (system call): 0x%lx\n"), ltmp
);
3950 do_cleanups (cleanup
);
3953 warning (_("unable to open /proc file '%s'"), fname1
);
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. */
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
)
3972 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
3975 /* Don't bother for one word. */
3976 if (len
< 3 * sizeof (long))
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
);
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
3991 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
3993 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
4003 /* Parse LINE as a signal set and add its set bits to SIGS. */
4006 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4008 int len
= strlen (line
) - 1;
4012 if (line
[len
] != '\n')
4013 error (_("Could not parse signal set: %s"), line
);
4021 if (*p
>= '0' && *p
<= '9')
4023 else if (*p
>= 'a' && *p
<= 'f')
4024 digit
= *p
- 'a' + 10;
4026 error (_("Could not parse signal set: %s"), line
);
4031 sigaddset (sigs
, signum
+ 1);
4033 sigaddset (sigs
, signum
+ 2);
4035 sigaddset (sigs
, signum
+ 3);
4037 sigaddset (sigs
, signum
+ 4);
4043 /* Find process PID's pending signals from /proc/pid/status and set
4047 linux_proc_pending_signals (int pid
, sigset_t
*pending
, sigset_t
*blocked
, sigset_t
*ignored
)
4050 char buffer
[MAXPATHLEN
], fname
[MAXPATHLEN
];
4052 struct cleanup
*cleanup
;
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
);
4063 while (fgets (buffer
, MAXPATHLEN
, procfile
) != NULL
)
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
4070 Unfortunately some Red Hat kernels include the shared pending
4071 queue but not the ShdPnd status field. */
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
);
4083 do_cleanups (cleanup
);
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
)
4091 /* We make the process list snapshot when the object starts to be
4093 static const char *buf
;
4094 static LONGEST len_avail
= -1;
4095 static struct obstack obstack
;
4099 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4101 if (strcmp (annex
, "processes") != 0)
4104 gdb_assert (readbuf
&& !writebuf
);
4108 if (len_avail
!= -1 && len_avail
!= 0)
4109 obstack_free (&obstack
, NULL
);
4112 obstack_init (&obstack
);
4113 obstack_grow_str (&obstack
, "<osdata type=\"processes\">\n");
4115 dirp
= opendir ("/proc");
4119 while ((dp
= readdir (dirp
)) != NULL
)
4121 struct stat statbuf
;
4122 char procentry
[sizeof ("/proc/4294967295")];
4124 if (!isdigit (dp
->d_name
[0])
4125 || NAMELEN (dp
) > sizeof ("4294967295") - 1)
4128 sprintf (procentry
, "/proc/%s", dp
->d_name
);
4129 if (stat (procentry
, &statbuf
) == 0
4130 && S_ISDIR (statbuf
.st_mode
))
4134 char cmd
[MAXPATHLEN
+ 1];
4135 struct passwd
*entry
;
4137 pathname
= xstrprintf ("/proc/%s/cmdline", dp
->d_name
);
4138 entry
= getpwuid (statbuf
.st_uid
);
4140 if ((f
= fopen (pathname
, "r")) != NULL
)
4142 size_t len
= fread (cmd
, 1, sizeof (cmd
) - 1, f
);
4146 for (i
= 0; i
< len
; i
++)
4151 obstack_xml_printf (
4154 "<column name=\"pid\">%s</column>"
4155 "<column name=\"user\">%s</column>"
4156 "<column name=\"command\">%s</column>"
4159 entry
? entry
->pw_name
: "?",
4172 obstack_grow_str0 (&obstack
, "</osdata>\n");
4173 buf
= obstack_finish (&obstack
);
4174 len_avail
= strlen (buf
);
4177 if (offset
>= len_avail
)
4179 /* Done. Get rid of the obstack. */
4180 obstack_free (&obstack
, NULL
);
4186 if (len
> len_avail
- offset
)
4187 len
= len_avail
- offset
;
4188 memcpy (readbuf
, buf
+ offset
, len
);
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
)
4200 if (object
== TARGET_OBJECT_AUXV
)
4201 return procfs_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4204 if (object
== TARGET_OBJECT_OSDATA
)
4205 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4208 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4213 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4217 /* Create a prototype generic GNU/Linux target. The client can override
4218 it with local methods. */
4221 linux_target_install_ops (struct target_ops
*t
)
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
;
4233 super_xfer_partial
= t
->to_xfer_partial
;
4234 t
->to_xfer_partial
= linux_xfer_partial
;
4240 struct target_ops
*t
;
4242 t
= inf_ptrace_target ();
4243 linux_target_install_ops (t
);
4249 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4251 struct target_ops
*t
;
4253 t
= inf_ptrace_trad_target (register_u_offset
);
4254 linux_target_install_ops (t
);
4259 /* target_is_async_p implementation. */
4262 linux_nat_is_async_p (void)
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
)
4270 /* See target.h/target_async_mask. */
4271 return linux_nat_async_mask_value
;
4274 /* target_can_async_p implementation. */
4277 linux_nat_can_async_p (void)
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
)
4285 /* See target.h/target_async_mask. */
4286 return linux_nat_async_mask_value
;
4290 linux_nat_supports_non_stop (void)
4295 /* True if we want to support multi-process. To be removed when GDB
4296 supports multi-exec. */
4298 int linux_multi_process
= 0;
4301 linux_nat_supports_multi_process (void)
4303 return linux_multi_process
;
4306 /* target_async_mask implementation. */
4309 linux_nat_async_mask (int new_mask
)
4311 int curr_mask
= linux_nat_async_mask_value
;
4313 if (curr_mask
!= new_mask
)
4317 linux_nat_async (NULL
, 0);
4318 linux_nat_async_mask_value
= new_mask
;
4322 linux_nat_async_mask_value
= new_mask
;
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
4330 linux_nat_async (inferior_event_handler
, 0);
4337 static int async_terminal_is_ours
= 1;
4339 /* target_terminal_inferior implementation. */
4342 linux_nat_terminal_inferior (void)
4344 if (!target_is_async_p ())
4346 /* Async mode is disabled. */
4347 terminal_inferior ();
4351 terminal_inferior ();
4353 /* Calls to target_terminal_*() are meant to be idempotent. */
4354 if (!async_terminal_is_ours
)
4357 delete_file_handler (input_fd
);
4358 async_terminal_is_ours
= 0;
4362 /* target_terminal_ours implementation. */
4365 linux_nat_terminal_ours (void)
4367 if (!target_is_async_p ())
4369 /* Async mode is disabled. */
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. */
4379 if (async_terminal_is_ours
)
4382 clear_sigint_trap ();
4383 add_file_handler (input_fd
, stdin_event_handler
, 0);
4384 async_terminal_is_ours
= 1;
4387 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4389 static void *async_client_context
;
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. */
4397 sigchld_handler (int signo
)
4399 int old_errno
= errno
;
4401 if (debug_linux_nat_async
)
4402 fprintf_unfiltered (gdb_stdlog
, "sigchld\n");
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. */
4412 /* Callback registered with the target events file descriptor. */
4415 handle_target_event (int error
, gdb_client_data client_data
)
4417 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4420 /* Create/destroy the target events pipe. Returns previous state. */
4423 linux_async_pipe (int enable
)
4425 int previous
= (linux_nat_event_pipe
[0] != -1);
4427 if (previous
!= enable
)
4431 block_child_signals (&prev_mask
);
4435 if (pipe (linux_nat_event_pipe
) == -1)
4436 internal_error (__FILE__
, __LINE__
,
4437 "creating event pipe failed.");
4439 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4440 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
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;
4450 restore_child_signals_mask (&prev_mask
);
4456 /* target_async implementation. */
4459 linux_nat_async (void (*callback
) (enum inferior_event_type event_type
,
4460 void *context
), void *context
)
4462 if (linux_nat_async_mask_value
== 0 || !target_async_permitted
)
4463 internal_error (__FILE__
, __LINE__
,
4464 "Calling target_async when async is masked");
4466 if (callback
!= NULL
)
4468 async_client_callback
= callback
;
4469 async_client_context
= context
;
4470 if (!linux_async_pipe (1))
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
4481 async_client_callback
= callback
;
4482 async_client_context
= context
;
4483 delete_file_handler (linux_nat_event_pipe
[0]);
4484 linux_async_pipe (0);
4489 /* Stop an LWP, and push a TARGET_SIGNAL_0 stop status if no other
4493 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4498 ptid_t ptid
= lwp
->ptid
;
4500 if (debug_linux_nat
)
4501 fprintf_unfiltered (gdb_stdlog
,
4502 "LNSL: running -> suspending %s\n",
4503 target_pid_to_str (lwp
->ptid
));
4506 stop_callback (lwp
, NULL
);
4507 stop_wait_callback (lwp
, NULL
);
4509 /* If the lwp exits while we try to stop it, there's nothing
4511 lwp
= find_lwp_pid (ptid
);
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
4519 if (lwp
->status
== 0)
4520 lwp
->status
= W_STOPCODE (0);
4525 /* Already known to be stopped; do nothing. */
4527 if (debug_linux_nat
)
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
));
4534 fprintf_unfiltered (gdb_stdlog
, "\
4535 LNSL: already stopped/no stop_requested yet %s\n",
4536 target_pid_to_str (lwp
->ptid
));
4543 linux_nat_stop (ptid_t ptid
)
4546 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4548 linux_ops
->to_stop (ptid
);
4552 linux_nat_close (int quitting
)
4554 /* Unregister from the event loop. */
4555 if (target_is_async_p ())
4556 target_async (NULL
, 0);
4558 /* Reset the async_masking. */
4559 linux_nat_async_mask_value
= 1;
4561 if (linux_ops
->to_close
)
4562 linux_ops
->to_close (quitting
);
4566 linux_nat_add_target (struct target_ops
*t
)
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
;
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
;
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
;
4597 /* Methods for non-stop support. */
4598 t
->to_stop
= linux_nat_stop
;
4600 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
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. */
4611 /* Register a method to call whenever a new thread is attached. */
4613 linux_nat_set_new_thread (struct target_ops
*t
, void (*new_thread
) (ptid_t
))
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
4618 linux_nat_new_thread
= new_thread
;
4621 /* Register a method that converts a siginfo object between the layout
4622 that ptrace returns, and the layout in the architecture of the
4625 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4626 int (*siginfo_fixup
) (struct siginfo
*,
4630 /* Save the pointer. */
4631 linux_nat_siginfo_fixup
= siginfo_fixup
;
4634 /* Return the saved siginfo associated with PTID. */
4636 linux_nat_get_siginfo (ptid_t ptid
)
4638 struct lwp_info
*lp
= find_lwp_pid (ptid
);
4640 gdb_assert (lp
!= NULL
);
4642 return &lp
->siginfo
;
4645 /* Provide a prototype to silence -Wmissing-prototypes. */
4646 extern initialize_file_ftype _initialize_linux_nat
;
4649 _initialize_linux_nat (void)
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."));
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."),
4668 show_debug_linux_nat
,
4669 &setdebuglist
, &showdebuglist
);
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."),
4677 show_debug_linux_nat_async
,
4678 &setdebuglist
, &showdebuglist
);
4680 /* Save this mask as the default. */
4681 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
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
;
4688 /* Make it the default. */
4689 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4691 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4692 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4693 sigdelset (&suspend_mask
, SIGCHLD
);
4695 sigemptyset (&blocked_mask
);
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
);
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
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
4719 get_signo (const char *name
)
4721 struct minimal_symbol
*ms
;
4724 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
4728 if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
4729 sizeof (signo
)) != 0)
4735 /* Return the set of signals used by the threads library in *SET. */
4738 lin_thread_get_thread_signals (sigset_t
*set
)
4740 struct sigaction action
;
4741 int restart
, cancel
;
4743 sigemptyset (&blocked_mask
);
4746 restart
= get_signo ("__pthread_sig_restart");
4747 cancel
= get_signo ("__pthread_sig_cancel");
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! */
4755 restart
= __SIGRTMIN
;
4758 cancel
= __SIGRTMIN
+ 1;
4760 sigaddset (set
, restart
);
4761 sigaddset (set
, cancel
);
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
4769 action
.sa_handler
= sigchld_handler
;
4770 sigemptyset (&action
.sa_mask
);
4771 action
.sa_flags
= SA_RESTART
;
4772 sigaction (cancel
, &action
, NULL
);
4774 /* We block the "cancel" signal throughout this code ... */
4775 sigaddset (&blocked_mask
, cancel
);
4776 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
4778 /* ... except during a sigsuspend. */
4779 sigdelset (&suspend_mask
, cancel
);