1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2013 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "nat/linux-nat.h"
24 #include "nat/linux-waitpid.h"
27 #include "gdb_assert.h"
28 #ifdef HAVE_TKILL_SYSCALL
30 #include <sys/syscall.h>
32 #include <sys/ptrace.h>
33 #include "linux-nat.h"
34 #include "linux-ptrace.h"
35 #include "linux-procfs.h"
36 #include "linux-fork.h"
37 #include "gdbthread.h"
41 #include "inf-child.h"
42 #include "inf-ptrace.h"
44 #include <sys/procfs.h> /* for elf_gregset etc. */
45 #include "elf-bfd.h" /* for elfcore_write_* */
46 #include "gregset.h" /* for gregset */
47 #include "gdbcore.h" /* for get_exec_file */
48 #include <ctype.h> /* for isdigit */
49 #include "gdbthread.h" /* for struct thread_info etc. */
50 #include <sys/stat.h> /* for struct stat */
51 #include <fcntl.h> /* for O_RDONLY */
53 #include "event-loop.h"
54 #include "event-top.h"
56 #include <sys/types.h>
58 #include "xml-support.h"
62 #include "linux-osdata.h"
63 #include "linux-tdep.h"
66 #include "tracepoint.h"
67 #include "exceptions.h"
68 #include "linux-ptrace.h"
70 #include "target-descriptions.h"
71 #include "filestuff.h"
74 #define SPUFS_MAGIC 0x23c9b64e
77 #ifdef HAVE_PERSONALITY
78 # include <sys/personality.h>
79 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
80 # define ADDR_NO_RANDOMIZE 0x0040000
82 #endif /* HAVE_PERSONALITY */
84 /* This comment documents high-level logic of this file.
86 Waiting for events in sync mode
87 ===============================
89 When waiting for an event in a specific thread, we just use waitpid, passing
90 the specific pid, and not passing WNOHANG.
92 When waiting for an event in all threads, waitpid is not quite good. Prior to
93 version 2.4, Linux can either wait for event in main thread, or in secondary
94 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
95 miss an event. The solution is to use non-blocking waitpid, together with
96 sigsuspend. First, we use non-blocking waitpid to get an event in the main
97 process, if any. Second, we use non-blocking waitpid with the __WCLONED
98 flag to check for events in cloned processes. If nothing is found, we use
99 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
100 happened to a child process -- and SIGCHLD will be delivered both for events
101 in main debugged process and in cloned processes. As soon as we know there's
102 an event, we get back to calling nonblocking waitpid with and without
105 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
106 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
107 blocked, the signal becomes pending and sigsuspend immediately
108 notices it and returns.
110 Waiting for events in async mode
111 ================================
113 In async mode, GDB should always be ready to handle both user input
114 and target events, so neither blocking waitpid nor sigsuspend are
115 viable options. Instead, we should asynchronously notify the GDB main
116 event loop whenever there's an unprocessed event from the target. We
117 detect asynchronous target events by handling SIGCHLD signals. To
118 notify the event loop about target events, the self-pipe trick is used
119 --- a pipe is registered as waitable event source in the event loop,
120 the event loop select/poll's on the read end of this pipe (as well on
121 other event sources, e.g., stdin), and the SIGCHLD handler writes a
122 byte to this pipe. This is more portable than relying on
123 pselect/ppoll, since on kernels that lack those syscalls, libc
124 emulates them with select/poll+sigprocmask, and that is racy
125 (a.k.a. plain broken).
127 Obviously, if we fail to notify the event loop if there's a target
128 event, it's bad. OTOH, if we notify the event loop when there's no
129 event from the target, linux_nat_wait will detect that there's no real
130 event to report, and return event of type TARGET_WAITKIND_IGNORE.
131 This is mostly harmless, but it will waste time and is better avoided.
133 The main design point is that every time GDB is outside linux-nat.c,
134 we have a SIGCHLD handler installed that is called when something
135 happens to the target and notifies the GDB event loop. Whenever GDB
136 core decides to handle the event, and calls into linux-nat.c, we
137 process things as in sync mode, except that the we never block in
140 While processing an event, we may end up momentarily blocked in
141 waitpid calls. Those waitpid calls, while blocking, are guarantied to
142 return quickly. E.g., in all-stop mode, before reporting to the core
143 that an LWP hit a breakpoint, all LWPs are stopped by sending them
144 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
145 Note that this is different from blocking indefinitely waiting for the
146 next event --- here, we're already handling an event.
151 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
152 signal is not entirely significant; we just need for a signal to be delivered,
153 so that we can intercept it. SIGSTOP's advantage is that it can not be
154 blocked. A disadvantage is that it is not a real-time signal, so it can only
155 be queued once; we do not keep track of other sources of SIGSTOP.
157 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
158 use them, because they have special behavior when the signal is generated -
159 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
160 kills the entire thread group.
162 A delivered SIGSTOP would stop the entire thread group, not just the thread we
163 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
164 cancel it (by PTRACE_CONT without passing SIGSTOP).
166 We could use a real-time signal instead. This would solve those problems; we
167 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
168 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
169 generates it, and there are races with trying to find a signal that is not
173 #define O_LARGEFILE 0
176 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
177 the use of the multi-threaded target. */
178 static struct target_ops *linux_ops;
179 static struct target_ops linux_ops_saved;
181 /* The method to call, if any, when a new thread is attached. */
182 static void (*linux_nat_new_thread) (struct lwp_info *);
184 /* The method to call, if any, when a new fork is attached. */
185 static linux_nat_new_fork_ftype *linux_nat_new_fork;
187 /* The method to call, if any, when a process is no longer
189 static linux_nat_forget_process_ftype *linux_nat_forget_process_hook;
191 /* Hook to call prior to resuming a thread. */
192 static void (*linux_nat_prepare_to_resume) (struct lwp_info *);
194 /* The method to call, if any, when the siginfo object needs to be
195 converted between the layout returned by ptrace, and the layout in
196 the architecture of the inferior. */
197 static int (*linux_nat_siginfo_fixup) (siginfo_t *,
201 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
202 Called by our to_xfer_partial. */
203 static target_xfer_partial_ftype *super_xfer_partial;
205 static unsigned int debug_linux_nat;
207 show_debug_linux_nat (struct ui_file *file, int from_tty,
208 struct cmd_list_element *c, const char *value)
210 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
214 struct simple_pid_list
218 struct simple_pid_list *next;
220 struct simple_pid_list *stopped_pids;
222 /* Async mode support. */
224 /* The read/write ends of the pipe registered as waitable file in the
226 static int linux_nat_event_pipe[2] = { -1, -1 };
228 /* Flush the event pipe. */
231 async_file_flush (void)
238 ret = read (linux_nat_event_pipe[0], &buf, 1);
240 while (ret >= 0 || (ret == -1 && errno == EINTR));
243 /* Put something (anything, doesn't matter what, or how much) in event
244 pipe, so that the select/poll in the event-loop realizes we have
245 something to process. */
248 async_file_mark (void)
252 /* It doesn't really matter what the pipe contains, as long we end
253 up with something in it. Might as well flush the previous
259 ret = write (linux_nat_event_pipe[1], "+", 1);
261 while (ret == -1 && errno == EINTR);
263 /* Ignore EAGAIN. If the pipe is full, the event loop will already
264 be awakened anyway. */
267 static void linux_nat_async (void (*callback)
268 (enum inferior_event_type event_type,
271 static int kill_lwp (int lwpid, int signo);
273 static int stop_callback (struct lwp_info *lp, void *data);
275 static void block_child_signals (sigset_t *prev_mask);
276 static void restore_child_signals_mask (sigset_t *prev_mask);
279 static struct lwp_info *add_lwp (ptid_t ptid);
280 static void purge_lwp_list (int pid);
281 static void delete_lwp (ptid_t ptid);
282 static struct lwp_info *find_lwp_pid (ptid_t ptid);
285 /* Trivial list manipulation functions to keep track of a list of
286 new stopped processes. */
288 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
290 struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
293 new_pid->status = status;
294 new_pid->next = *listp;
299 in_pid_list_p (struct simple_pid_list *list, int pid)
301 struct simple_pid_list *p;
303 for (p = list; p != NULL; p = p->next)
310 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
312 struct simple_pid_list **p;
314 for (p = listp; *p != NULL; p = &(*p)->next)
315 if ((*p)->pid == pid)
317 struct simple_pid_list *next = (*p)->next;
319 *statusp = (*p)->status;
327 /* Initialize ptrace warnings and check for supported ptrace
328 features given PID. */
331 linux_init_ptrace (pid_t pid)
333 linux_enable_event_reporting (pid);
334 linux_ptrace_init_warnings ();
338 linux_child_post_attach (int pid)
340 linux_init_ptrace (pid);
344 linux_child_post_startup_inferior (ptid_t ptid)
346 linux_init_ptrace (ptid_get_pid (ptid));
349 /* Return the number of known LWPs in the tgid given by PID. */
357 for (lp = lwp_list; lp; lp = lp->next)
358 if (ptid_get_pid (lp->ptid) == pid)
364 /* Call delete_lwp with prototype compatible for make_cleanup. */
367 delete_lwp_cleanup (void *lp_voidp)
369 struct lwp_info *lp = lp_voidp;
371 delete_lwp (lp->ptid);
375 linux_child_follow_fork (struct target_ops *ops, int follow_child,
379 int parent_pid, child_pid;
381 has_vforked = (inferior_thread ()->pending_follow.kind
382 == TARGET_WAITKIND_VFORKED);
383 parent_pid = ptid_get_lwp (inferior_ptid);
385 parent_pid = ptid_get_pid (inferior_ptid);
387 = ptid_get_pid (inferior_thread ()->pending_follow.value.related_pid);
390 && !non_stop /* Non-stop always resumes both branches. */
391 && (!target_is_async_p () || sync_execution)
392 && !(follow_child || detach_fork || sched_multi))
394 /* The parent stays blocked inside the vfork syscall until the
395 child execs or exits. If we don't let the child run, then
396 the parent stays blocked. If we're telling the parent to run
397 in the foreground, the user will not be able to ctrl-c to get
398 back the terminal, effectively hanging the debug session. */
399 fprintf_filtered (gdb_stderr, _("\
400 Can not resume the parent process over vfork in the foreground while\n\
401 holding the child stopped. Try \"set detach-on-fork\" or \
402 \"set schedule-multiple\".\n"));
403 /* FIXME output string > 80 columns. */
409 struct lwp_info *child_lp = NULL;
411 /* We're already attached to the parent, by default. */
413 /* Detach new forked process? */
416 struct cleanup *old_chain;
418 /* Before detaching from the child, remove all breakpoints
419 from it. If we forked, then this has already been taken
420 care of by infrun.c. If we vforked however, any
421 breakpoint inserted in the parent is visible in the
422 child, even those added while stopped in a vfork
423 catchpoint. This will remove the breakpoints from the
424 parent also, but they'll be reinserted below. */
427 /* keep breakpoints list in sync. */
428 remove_breakpoints_pid (ptid_get_pid (inferior_ptid));
431 if (info_verbose || debug_linux_nat)
433 target_terminal_ours ();
434 fprintf_filtered (gdb_stdlog,
435 "Detaching after fork from "
436 "child process %d.\n",
440 old_chain = save_inferior_ptid ();
441 inferior_ptid = ptid_build (child_pid, child_pid, 0);
443 child_lp = add_lwp (inferior_ptid);
444 child_lp->stopped = 1;
445 child_lp->last_resume_kind = resume_stop;
446 make_cleanup (delete_lwp_cleanup, child_lp);
448 if (linux_nat_prepare_to_resume != NULL)
449 linux_nat_prepare_to_resume (child_lp);
450 ptrace (PTRACE_DETACH, child_pid, 0, 0);
452 do_cleanups (old_chain);
456 struct inferior *parent_inf, *child_inf;
457 struct cleanup *old_chain;
459 /* Add process to GDB's tables. */
460 child_inf = add_inferior (child_pid);
462 parent_inf = current_inferior ();
463 child_inf->attach_flag = parent_inf->attach_flag;
464 copy_terminal_info (child_inf, parent_inf);
465 child_inf->gdbarch = parent_inf->gdbarch;
466 copy_inferior_target_desc_info (child_inf, parent_inf);
468 old_chain = save_inferior_ptid ();
469 save_current_program_space ();
471 inferior_ptid = ptid_build (child_pid, child_pid, 0);
472 add_thread (inferior_ptid);
473 child_lp = add_lwp (inferior_ptid);
474 child_lp->stopped = 1;
475 child_lp->last_resume_kind = resume_stop;
476 child_inf->symfile_flags = SYMFILE_NO_READ;
478 /* If this is a vfork child, then the address-space is
479 shared with the parent. */
482 child_inf->pspace = parent_inf->pspace;
483 child_inf->aspace = parent_inf->aspace;
485 /* The parent will be frozen until the child is done
486 with the shared region. Keep track of the
488 child_inf->vfork_parent = parent_inf;
489 child_inf->pending_detach = 0;
490 parent_inf->vfork_child = child_inf;
491 parent_inf->pending_detach = 0;
495 child_inf->aspace = new_address_space ();
496 child_inf->pspace = add_program_space (child_inf->aspace);
497 child_inf->removable = 1;
498 set_current_program_space (child_inf->pspace);
499 clone_program_space (child_inf->pspace, parent_inf->pspace);
501 /* Let the shared library layer (solib-svr4) learn about
502 this new process, relocate the cloned exec, pull in
503 shared libraries, and install the solib event
504 breakpoint. If a "cloned-VM" event was propagated
505 better throughout the core, this wouldn't be
507 solib_create_inferior_hook (0);
510 /* Let the thread_db layer learn about this new process. */
511 check_for_thread_db ();
513 do_cleanups (old_chain);
518 struct lwp_info *parent_lp;
519 struct inferior *parent_inf;
521 parent_inf = current_inferior ();
523 /* If we detached from the child, then we have to be careful
524 to not insert breakpoints in the parent until the child
525 is done with the shared memory region. However, if we're
526 staying attached to the child, then we can and should
527 insert breakpoints, so that we can debug it. A
528 subsequent child exec or exit is enough to know when does
529 the child stops using the parent's address space. */
530 parent_inf->waiting_for_vfork_done = detach_fork;
531 parent_inf->pspace->breakpoints_not_allowed = detach_fork;
533 parent_lp = find_lwp_pid (pid_to_ptid (parent_pid));
534 gdb_assert (linux_supports_tracefork () >= 0);
536 if (linux_supports_tracevforkdone ())
539 fprintf_unfiltered (gdb_stdlog,
540 "LCFF: waiting for VFORK_DONE on %d\n",
542 parent_lp->stopped = 1;
544 /* We'll handle the VFORK_DONE event like any other
545 event, in target_wait. */
549 /* We can't insert breakpoints until the child has
550 finished with the shared memory region. We need to
551 wait until that happens. Ideal would be to just
553 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
554 - waitpid (parent_pid, &status, __WALL);
555 However, most architectures can't handle a syscall
556 being traced on the way out if it wasn't traced on
559 We might also think to loop, continuing the child
560 until it exits or gets a SIGTRAP. One problem is
561 that the child might call ptrace with PTRACE_TRACEME.
563 There's no simple and reliable way to figure out when
564 the vforked child will be done with its copy of the
565 shared memory. We could step it out of the syscall,
566 two instructions, let it go, and then single-step the
567 parent once. When we have hardware single-step, this
568 would work; with software single-step it could still
569 be made to work but we'd have to be able to insert
570 single-step breakpoints in the child, and we'd have
571 to insert -just- the single-step breakpoint in the
572 parent. Very awkward.
574 In the end, the best we can do is to make sure it
575 runs for a little while. Hopefully it will be out of
576 range of any breakpoints we reinsert. Usually this
577 is only the single-step breakpoint at vfork's return
581 fprintf_unfiltered (gdb_stdlog,
582 "LCFF: no VFORK_DONE "
583 "support, sleeping a bit\n");
587 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
588 and leave it pending. The next linux_nat_resume call
589 will notice a pending event, and bypasses actually
590 resuming the inferior. */
591 parent_lp->status = 0;
592 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
593 parent_lp->stopped = 1;
595 /* If we're in async mode, need to tell the event loop
596 there's something here to process. */
597 if (target_can_async_p ())
604 struct inferior *parent_inf, *child_inf;
605 struct lwp_info *child_lp;
606 struct program_space *parent_pspace;
608 if (info_verbose || debug_linux_nat)
610 target_terminal_ours ();
612 fprintf_filtered (gdb_stdlog,
613 _("Attaching after process %d "
614 "vfork to child process %d.\n"),
615 parent_pid, child_pid);
617 fprintf_filtered (gdb_stdlog,
618 _("Attaching after process %d "
619 "fork to child process %d.\n"),
620 parent_pid, child_pid);
623 /* Add the new inferior first, so that the target_detach below
624 doesn't unpush the target. */
626 child_inf = add_inferior (child_pid);
628 parent_inf = current_inferior ();
629 child_inf->attach_flag = parent_inf->attach_flag;
630 copy_terminal_info (child_inf, parent_inf);
631 child_inf->gdbarch = parent_inf->gdbarch;
632 copy_inferior_target_desc_info (child_inf, parent_inf);
634 parent_pspace = parent_inf->pspace;
636 /* If we're vforking, we want to hold on to the parent until the
637 child exits or execs. At child exec or exit time we can
638 remove the old breakpoints from the parent and detach or
639 resume debugging it. Otherwise, detach the parent now; we'll
640 want to reuse it's program/address spaces, but we can't set
641 them to the child before removing breakpoints from the
642 parent, otherwise, the breakpoints module could decide to
643 remove breakpoints from the wrong process (since they'd be
644 assigned to the same address space). */
648 gdb_assert (child_inf->vfork_parent == NULL);
649 gdb_assert (parent_inf->vfork_child == NULL);
650 child_inf->vfork_parent = parent_inf;
651 child_inf->pending_detach = 0;
652 parent_inf->vfork_child = child_inf;
653 parent_inf->pending_detach = detach_fork;
654 parent_inf->waiting_for_vfork_done = 0;
656 else if (detach_fork)
657 target_detach (NULL, 0);
659 /* Note that the detach above makes PARENT_INF dangling. */
661 /* Add the child thread to the appropriate lists, and switch to
662 this new thread, before cloning the program space, and
663 informing the solib layer about this new process. */
665 inferior_ptid = ptid_build (child_pid, child_pid, 0);
666 add_thread (inferior_ptid);
667 child_lp = add_lwp (inferior_ptid);
668 child_lp->stopped = 1;
669 child_lp->last_resume_kind = resume_stop;
671 /* If this is a vfork child, then the address-space is shared
672 with the parent. If we detached from the parent, then we can
673 reuse the parent's program/address spaces. */
674 if (has_vforked || detach_fork)
676 child_inf->pspace = parent_pspace;
677 child_inf->aspace = child_inf->pspace->aspace;
681 child_inf->aspace = new_address_space ();
682 child_inf->pspace = add_program_space (child_inf->aspace);
683 child_inf->removable = 1;
684 child_inf->symfile_flags = SYMFILE_NO_READ;
685 set_current_program_space (child_inf->pspace);
686 clone_program_space (child_inf->pspace, parent_pspace);
688 /* Let the shared library layer (solib-svr4) learn about
689 this new process, relocate the cloned exec, pull in
690 shared libraries, and install the solib event breakpoint.
691 If a "cloned-VM" event was propagated better throughout
692 the core, this wouldn't be required. */
693 solib_create_inferior_hook (0);
696 /* Let the thread_db layer learn about this new process. */
697 check_for_thread_db ();
705 linux_child_insert_fork_catchpoint (int pid)
707 return !linux_supports_tracefork ();
711 linux_child_remove_fork_catchpoint (int pid)
717 linux_child_insert_vfork_catchpoint (int pid)
719 return !linux_supports_tracefork ();
723 linux_child_remove_vfork_catchpoint (int pid)
729 linux_child_insert_exec_catchpoint (int pid)
731 return !linux_supports_tracefork ();
735 linux_child_remove_exec_catchpoint (int pid)
741 linux_child_set_syscall_catchpoint (int pid, int needed, int any_count,
742 int table_size, int *table)
744 if (!linux_supports_tracesysgood ())
747 /* On GNU/Linux, we ignore the arguments. It means that we only
748 enable the syscall catchpoints, but do not disable them.
750 Also, we do not use the `table' information because we do not
751 filter system calls here. We let GDB do the logic for us. */
755 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
756 are processes sharing the same VM space. A multi-threaded process
757 is basically a group of such processes. However, such a grouping
758 is almost entirely a user-space issue; the kernel doesn't enforce
759 such a grouping at all (this might change in the future). In
760 general, we'll rely on the threads library (i.e. the GNU/Linux
761 Threads library) to provide such a grouping.
763 It is perfectly well possible to write a multi-threaded application
764 without the assistance of a threads library, by using the clone
765 system call directly. This module should be able to give some
766 rudimentary support for debugging such applications if developers
767 specify the CLONE_PTRACE flag in the clone system call, and are
768 using the Linux kernel 2.4 or above.
770 Note that there are some peculiarities in GNU/Linux that affect
773 - In general one should specify the __WCLONE flag to waitpid in
774 order to make it report events for any of the cloned processes
775 (and leave it out for the initial process). However, if a cloned
776 process has exited the exit status is only reported if the
777 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
778 we cannot use it since GDB must work on older systems too.
780 - When a traced, cloned process exits and is waited for by the
781 debugger, the kernel reassigns it to the original parent and
782 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
783 library doesn't notice this, which leads to the "zombie problem":
784 When debugged a multi-threaded process that spawns a lot of
785 threads will run out of processes, even if the threads exit,
786 because the "zombies" stay around. */
788 /* List of known LWPs. */
789 struct lwp_info *lwp_list;
792 /* Original signal mask. */
793 static sigset_t normal_mask;
795 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
796 _initialize_linux_nat. */
797 static sigset_t suspend_mask;
799 /* Signals to block to make that sigsuspend work. */
800 static sigset_t blocked_mask;
802 /* SIGCHLD action. */
803 struct sigaction sigchld_action;
805 /* Block child signals (SIGCHLD and linux threads signals), and store
806 the previous mask in PREV_MASK. */
809 block_child_signals (sigset_t *prev_mask)
811 /* Make sure SIGCHLD is blocked. */
812 if (!sigismember (&blocked_mask, SIGCHLD))
813 sigaddset (&blocked_mask, SIGCHLD);
815 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
818 /* Restore child signals mask, previously returned by
819 block_child_signals. */
822 restore_child_signals_mask (sigset_t *prev_mask)
824 sigprocmask (SIG_SETMASK, prev_mask, NULL);
827 /* Mask of signals to pass directly to the inferior. */
828 static sigset_t pass_mask;
830 /* Update signals to pass to the inferior. */
832 linux_nat_pass_signals (int numsigs, unsigned char *pass_signals)
836 sigemptyset (&pass_mask);
838 for (signo = 1; signo < NSIG; signo++)
840 int target_signo = gdb_signal_from_host (signo);
841 if (target_signo < numsigs && pass_signals[target_signo])
842 sigaddset (&pass_mask, signo);
848 /* Prototypes for local functions. */
849 static int stop_wait_callback (struct lwp_info *lp, void *data);
850 static int linux_thread_alive (ptid_t ptid);
851 static char *linux_child_pid_to_exec_file (int pid);
854 /* Convert wait status STATUS to a string. Used for printing debug
858 status_to_str (int status)
862 if (WIFSTOPPED (status))
864 if (WSTOPSIG (status) == SYSCALL_SIGTRAP)
865 snprintf (buf, sizeof (buf), "%s (stopped at syscall)",
866 strsignal (SIGTRAP));
868 snprintf (buf, sizeof (buf), "%s (stopped)",
869 strsignal (WSTOPSIG (status)));
871 else if (WIFSIGNALED (status))
872 snprintf (buf, sizeof (buf), "%s (terminated)",
873 strsignal (WTERMSIG (status)));
875 snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status));
880 /* Destroy and free LP. */
883 lwp_free (struct lwp_info *lp)
885 xfree (lp->arch_private);
889 /* Remove all LWPs belong to PID from the lwp list. */
892 purge_lwp_list (int pid)
894 struct lwp_info *lp, *lpprev, *lpnext;
898 for (lp = lwp_list; lp; lp = lpnext)
902 if (ptid_get_pid (lp->ptid) == pid)
907 lpprev->next = lp->next;
916 /* Add the LWP specified by PTID to the list. PTID is the first LWP
917 in the process. Return a pointer to the structure describing the
920 This differs from add_lwp in that we don't let the arch specific
921 bits know about this new thread. Current clients of this callback
922 take the opportunity to install watchpoints in the new thread, and
923 we shouldn't do that for the first thread. If we're spawning a
924 child ("run"), the thread executes the shell wrapper first, and we
925 shouldn't touch it until it execs the program we want to debug.
926 For "attach", it'd be okay to call the callback, but it's not
927 necessary, because watchpoints can't yet have been inserted into
930 static struct lwp_info *
931 add_initial_lwp (ptid_t ptid)
935 gdb_assert (ptid_lwp_p (ptid));
937 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
939 memset (lp, 0, sizeof (struct lwp_info));
941 lp->last_resume_kind = resume_continue;
942 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
953 /* Add the LWP specified by PID to the list. Return a pointer to the
954 structure describing the new LWP. The LWP should already be
957 static struct lwp_info *
958 add_lwp (ptid_t ptid)
962 lp = add_initial_lwp (ptid);
964 /* Let the arch specific bits know about this new thread. Current
965 clients of this callback take the opportunity to install
966 watchpoints in the new thread. We don't do this for the first
967 thread though. See add_initial_lwp. */
968 if (linux_nat_new_thread != NULL)
969 linux_nat_new_thread (lp);
974 /* Remove the LWP specified by PID from the list. */
977 delete_lwp (ptid_t ptid)
979 struct lwp_info *lp, *lpprev;
983 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
984 if (ptid_equal (lp->ptid, ptid))
991 lpprev->next = lp->next;
998 /* Return a pointer to the structure describing the LWP corresponding
999 to PID. If no corresponding LWP could be found, return NULL. */
1001 static struct lwp_info *
1002 find_lwp_pid (ptid_t ptid)
1004 struct lwp_info *lp;
1007 if (ptid_lwp_p (ptid))
1008 lwp = ptid_get_lwp (ptid);
1010 lwp = ptid_get_pid (ptid);
1012 for (lp = lwp_list; lp; lp = lp->next)
1013 if (lwp == ptid_get_lwp (lp->ptid))
1019 /* Call CALLBACK with its second argument set to DATA for every LWP in
1020 the list. If CALLBACK returns 1 for a particular LWP, return a
1021 pointer to the structure describing that LWP immediately.
1022 Otherwise return NULL. */
1025 iterate_over_lwps (ptid_t filter,
1026 int (*callback) (struct lwp_info *, void *),
1029 struct lwp_info *lp, *lpnext;
1031 for (lp = lwp_list; lp; lp = lpnext)
1035 if (ptid_match (lp->ptid, filter))
1037 if ((*callback) (lp, data))
1045 /* Update our internal state when changing from one checkpoint to
1046 another indicated by NEW_PTID. We can only switch single-threaded
1047 applications, so we only create one new LWP, and the previous list
1051 linux_nat_switch_fork (ptid_t new_ptid)
1053 struct lwp_info *lp;
1055 purge_lwp_list (ptid_get_pid (inferior_ptid));
1057 lp = add_lwp (new_ptid);
1060 /* This changes the thread's ptid while preserving the gdb thread
1061 num. Also changes the inferior pid, while preserving the
1063 thread_change_ptid (inferior_ptid, new_ptid);
1065 /* We've just told GDB core that the thread changed target id, but,
1066 in fact, it really is a different thread, with different register
1068 registers_changed ();
1071 /* Handle the exit of a single thread LP. */
1074 exit_lwp (struct lwp_info *lp)
1076 struct thread_info *th = find_thread_ptid (lp->ptid);
1080 if (print_thread_events)
1081 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
1083 delete_thread (lp->ptid);
1086 delete_lwp (lp->ptid);
1089 /* Wait for the LWP specified by LP, which we have just attached to.
1090 Returns a wait status for that LWP, to cache. */
1093 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
1096 pid_t new_pid, pid = ptid_get_lwp (ptid);
1099 if (linux_proc_pid_is_stopped (pid))
1101 if (debug_linux_nat)
1102 fprintf_unfiltered (gdb_stdlog,
1103 "LNPAW: Attaching to a stopped process\n");
1105 /* The process is definitely stopped. It is in a job control
1106 stop, unless the kernel predates the TASK_STOPPED /
1107 TASK_TRACED distinction, in which case it might be in a
1108 ptrace stop. Make sure it is in a ptrace stop; from there we
1109 can kill it, signal it, et cetera.
1111 First make sure there is a pending SIGSTOP. Since we are
1112 already attached, the process can not transition from stopped
1113 to running without a PTRACE_CONT; so we know this signal will
1114 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1115 probably already in the queue (unless this kernel is old
1116 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1117 is not an RT signal, it can only be queued once. */
1118 kill_lwp (pid, SIGSTOP);
1120 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1121 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1122 ptrace (PTRACE_CONT, pid, 0, 0);
1125 /* Make sure the initial process is stopped. The user-level threads
1126 layer might want to poke around in the inferior, and that won't
1127 work if things haven't stabilized yet. */
1128 new_pid = my_waitpid (pid, &status, 0);
1129 if (new_pid == -1 && errno == ECHILD)
1132 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
1134 /* Try again with __WCLONE to check cloned processes. */
1135 new_pid = my_waitpid (pid, &status, __WCLONE);
1139 gdb_assert (pid == new_pid);
1141 if (!WIFSTOPPED (status))
1143 /* The pid we tried to attach has apparently just exited. */
1144 if (debug_linux_nat)
1145 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1146 pid, status_to_str (status));
1150 if (WSTOPSIG (status) != SIGSTOP)
1153 if (debug_linux_nat)
1154 fprintf_unfiltered (gdb_stdlog,
1155 "LNPAW: Received %s after attaching\n",
1156 status_to_str (status));
1162 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1163 the new LWP could not be attached, or 1 if we're already auto
1164 attached to this thread, but haven't processed the
1165 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1166 its existance, without considering it an error. */
1169 lin_lwp_attach_lwp (ptid_t ptid)
1171 struct lwp_info *lp;
1174 gdb_assert (ptid_lwp_p (ptid));
1176 lp = find_lwp_pid (ptid);
1177 lwpid = ptid_get_lwp (ptid);
1179 /* We assume that we're already attached to any LWP that has an id
1180 equal to the overall process id, and to any LWP that is already
1181 in our list of LWPs. If we're not seeing exit events from threads
1182 and we've had PID wraparound since we last tried to stop all threads,
1183 this assumption might be wrong; fortunately, this is very unlikely
1185 if (lwpid != ptid_get_pid (ptid) && lp == NULL)
1187 int status, cloned = 0, signalled = 0;
1189 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1191 if (linux_supports_tracefork ())
1193 /* If we haven't stopped all threads when we get here,
1194 we may have seen a thread listed in thread_db's list,
1195 but not processed the PTRACE_EVENT_CLONE yet. If
1196 that's the case, ignore this new thread, and let
1197 normal event handling discover it later. */
1198 if (in_pid_list_p (stopped_pids, lwpid))
1200 /* We've already seen this thread stop, but we
1201 haven't seen the PTRACE_EVENT_CLONE extended
1210 /* See if we've got a stop for this new child
1211 pending. If so, we're already attached. */
1212 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1213 if (new_pid == -1 && errno == ECHILD)
1214 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1217 if (WIFSTOPPED (status))
1218 add_to_pid_list (&stopped_pids, lwpid, status);
1224 /* If we fail to attach to the thread, issue a warning,
1225 but continue. One way this can happen is if thread
1226 creation is interrupted; as of Linux kernel 2.6.19, a
1227 bug may place threads in the thread list and then fail
1229 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1230 safe_strerror (errno));
1234 if (debug_linux_nat)
1235 fprintf_unfiltered (gdb_stdlog,
1236 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1237 target_pid_to_str (ptid));
1239 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1240 if (!WIFSTOPPED (status))
1243 lp = add_lwp (ptid);
1245 lp->cloned = cloned;
1246 lp->signalled = signalled;
1247 if (WSTOPSIG (status) != SIGSTOP)
1250 lp->status = status;
1253 target_post_attach (ptid_get_lwp (lp->ptid));
1255 if (debug_linux_nat)
1257 fprintf_unfiltered (gdb_stdlog,
1258 "LLAL: waitpid %s received %s\n",
1259 target_pid_to_str (ptid),
1260 status_to_str (status));
1265 /* We assume that the LWP representing the original process is
1266 already stopped. Mark it as stopped in the data structure
1267 that the GNU/linux ptrace layer uses to keep track of
1268 threads. Note that this won't have already been done since
1269 the main thread will have, we assume, been stopped by an
1270 attach from a different layer. */
1272 lp = add_lwp (ptid);
1276 lp->last_resume_kind = resume_stop;
1281 linux_nat_create_inferior (struct target_ops *ops,
1282 char *exec_file, char *allargs, char **env,
1285 #ifdef HAVE_PERSONALITY
1286 int personality_orig = 0, personality_set = 0;
1287 #endif /* HAVE_PERSONALITY */
1289 /* The fork_child mechanism is synchronous and calls target_wait, so
1290 we have to mask the async mode. */
1292 #ifdef HAVE_PERSONALITY
1293 if (disable_randomization)
1296 personality_orig = personality (0xffffffff);
1297 if (errno == 0 && !(personality_orig & ADDR_NO_RANDOMIZE))
1299 personality_set = 1;
1300 personality (personality_orig | ADDR_NO_RANDOMIZE);
1302 if (errno != 0 || (personality_set
1303 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE)))
1304 warning (_("Error disabling address space randomization: %s"),
1305 safe_strerror (errno));
1307 #endif /* HAVE_PERSONALITY */
1309 /* Make sure we report all signals during startup. */
1310 linux_nat_pass_signals (0, NULL);
1312 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1314 #ifdef HAVE_PERSONALITY
1315 if (personality_set)
1318 personality (personality_orig);
1320 warning (_("Error restoring address space randomization: %s"),
1321 safe_strerror (errno));
1323 #endif /* HAVE_PERSONALITY */
1327 linux_nat_attach (struct target_ops *ops, char *args, int from_tty)
1329 struct lwp_info *lp;
1332 volatile struct gdb_exception ex;
1334 /* Make sure we report all signals during attach. */
1335 linux_nat_pass_signals (0, NULL);
1337 TRY_CATCH (ex, RETURN_MASK_ERROR)
1339 linux_ops->to_attach (ops, args, from_tty);
1343 pid_t pid = parse_pid_to_attach (args);
1344 struct buffer buffer;
1345 char *message, *buffer_s;
1347 message = xstrdup (ex.message);
1348 make_cleanup (xfree, message);
1350 buffer_init (&buffer);
1351 linux_ptrace_attach_warnings (pid, &buffer);
1353 buffer_grow_str0 (&buffer, "");
1354 buffer_s = buffer_finish (&buffer);
1355 make_cleanup (xfree, buffer_s);
1357 throw_error (ex.error, "%s%s", buffer_s, message);
1360 /* The ptrace base target adds the main thread with (pid,0,0)
1361 format. Decorate it with lwp info. */
1362 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1363 ptid_get_pid (inferior_ptid),
1365 thread_change_ptid (inferior_ptid, ptid);
1367 /* Add the initial process as the first LWP to the list. */
1368 lp = add_initial_lwp (ptid);
1370 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1372 if (!WIFSTOPPED (status))
1374 if (WIFEXITED (status))
1376 int exit_code = WEXITSTATUS (status);
1378 target_terminal_ours ();
1379 target_mourn_inferior ();
1381 error (_("Unable to attach: program exited normally."));
1383 error (_("Unable to attach: program exited with code %d."),
1386 else if (WIFSIGNALED (status))
1388 enum gdb_signal signo;
1390 target_terminal_ours ();
1391 target_mourn_inferior ();
1393 signo = gdb_signal_from_host (WTERMSIG (status));
1394 error (_("Unable to attach: program terminated with signal "
1396 gdb_signal_to_name (signo),
1397 gdb_signal_to_string (signo));
1400 internal_error (__FILE__, __LINE__,
1401 _("unexpected status %d for PID %ld"),
1402 status, (long) ptid_get_lwp (ptid));
1407 /* Save the wait status to report later. */
1409 if (debug_linux_nat)
1410 fprintf_unfiltered (gdb_stdlog,
1411 "LNA: waitpid %ld, saving status %s\n",
1412 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1414 lp->status = status;
1416 if (target_can_async_p ())
1417 target_async (inferior_event_handler, 0);
1420 /* Get pending status of LP. */
1422 get_pending_status (struct lwp_info *lp, int *status)
1424 enum gdb_signal signo = GDB_SIGNAL_0;
1426 /* If we paused threads momentarily, we may have stored pending
1427 events in lp->status or lp->waitstatus (see stop_wait_callback),
1428 and GDB core hasn't seen any signal for those threads.
1429 Otherwise, the last signal reported to the core is found in the
1430 thread object's stop_signal.
1432 There's a corner case that isn't handled here at present. Only
1433 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1434 stop_signal make sense as a real signal to pass to the inferior.
1435 Some catchpoint related events, like
1436 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1437 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1438 those traps are debug API (ptrace in our case) related and
1439 induced; the inferior wouldn't see them if it wasn't being
1440 traced. Hence, we should never pass them to the inferior, even
1441 when set to pass state. Since this corner case isn't handled by
1442 infrun.c when proceeding with a signal, for consistency, neither
1443 do we handle it here (or elsewhere in the file we check for
1444 signal pass state). Normally SIGTRAP isn't set to pass state, so
1445 this is really a corner case. */
1447 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1448 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1449 else if (lp->status)
1450 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1451 else if (non_stop && !is_executing (lp->ptid))
1453 struct thread_info *tp = find_thread_ptid (lp->ptid);
1455 signo = tp->suspend.stop_signal;
1459 struct target_waitstatus last;
1462 get_last_target_status (&last_ptid, &last);
1464 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1466 struct thread_info *tp = find_thread_ptid (lp->ptid);
1468 signo = tp->suspend.stop_signal;
1474 if (signo == GDB_SIGNAL_0)
1476 if (debug_linux_nat)
1477 fprintf_unfiltered (gdb_stdlog,
1478 "GPT: lwp %s has no pending signal\n",
1479 target_pid_to_str (lp->ptid));
1481 else if (!signal_pass_state (signo))
1483 if (debug_linux_nat)
1484 fprintf_unfiltered (gdb_stdlog,
1485 "GPT: lwp %s had signal %s, "
1486 "but it is in no pass state\n",
1487 target_pid_to_str (lp->ptid),
1488 gdb_signal_to_string (signo));
1492 *status = W_STOPCODE (gdb_signal_to_host (signo));
1494 if (debug_linux_nat)
1495 fprintf_unfiltered (gdb_stdlog,
1496 "GPT: lwp %s has pending signal %s\n",
1497 target_pid_to_str (lp->ptid),
1498 gdb_signal_to_string (signo));
1505 detach_callback (struct lwp_info *lp, void *data)
1507 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1509 if (debug_linux_nat && lp->status)
1510 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1511 strsignal (WSTOPSIG (lp->status)),
1512 target_pid_to_str (lp->ptid));
1514 /* If there is a pending SIGSTOP, get rid of it. */
1517 if (debug_linux_nat)
1518 fprintf_unfiltered (gdb_stdlog,
1519 "DC: Sending SIGCONT to %s\n",
1520 target_pid_to_str (lp->ptid));
1522 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1526 /* We don't actually detach from the LWP that has an id equal to the
1527 overall process id just yet. */
1528 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1532 /* Pass on any pending signal for this LWP. */
1533 get_pending_status (lp, &status);
1535 if (linux_nat_prepare_to_resume != NULL)
1536 linux_nat_prepare_to_resume (lp);
1538 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1539 WSTOPSIG (status)) < 0)
1540 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1541 safe_strerror (errno));
1543 if (debug_linux_nat)
1544 fprintf_unfiltered (gdb_stdlog,
1545 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1546 target_pid_to_str (lp->ptid),
1547 strsignal (WSTOPSIG (status)));
1549 delete_lwp (lp->ptid);
1556 linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
1560 struct lwp_info *main_lwp;
1562 pid = ptid_get_pid (inferior_ptid);
1564 /* Don't unregister from the event loop, as there may be other
1565 inferiors running. */
1567 /* Stop all threads before detaching. ptrace requires that the
1568 thread is stopped to sucessfully detach. */
1569 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1570 /* ... and wait until all of them have reported back that
1571 they're no longer running. */
1572 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1574 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1576 /* Only the initial process should be left right now. */
1577 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1579 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1581 /* Pass on any pending signal for the last LWP. */
1582 if ((args == NULL || *args == '\0')
1583 && get_pending_status (main_lwp, &status) != -1
1584 && WIFSTOPPED (status))
1588 /* Put the signal number in ARGS so that inf_ptrace_detach will
1589 pass it along with PTRACE_DETACH. */
1591 xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
1593 if (debug_linux_nat)
1594 fprintf_unfiltered (gdb_stdlog,
1595 "LND: Sending signal %s to %s\n",
1597 target_pid_to_str (main_lwp->ptid));
1600 if (linux_nat_prepare_to_resume != NULL)
1601 linux_nat_prepare_to_resume (main_lwp);
1602 delete_lwp (main_lwp->ptid);
1604 if (forks_exist_p ())
1606 /* Multi-fork case. The current inferior_ptid is being detached
1607 from, but there are other viable forks to debug. Detach from
1608 the current fork, and context-switch to the first
1610 linux_fork_detach (args, from_tty);
1613 linux_ops->to_detach (ops, args, from_tty);
1619 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1623 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
1625 if (inf->vfork_child != NULL)
1627 if (debug_linux_nat)
1628 fprintf_unfiltered (gdb_stdlog,
1629 "RC: Not resuming %s (vfork parent)\n",
1630 target_pid_to_str (lp->ptid));
1632 else if (lp->status == 0
1633 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
1635 if (debug_linux_nat)
1636 fprintf_unfiltered (gdb_stdlog,
1637 "RC: Resuming sibling %s, %s, %s\n",
1638 target_pid_to_str (lp->ptid),
1639 (signo != GDB_SIGNAL_0
1640 ? strsignal (gdb_signal_to_host (signo))
1642 step ? "step" : "resume");
1644 if (linux_nat_prepare_to_resume != NULL)
1645 linux_nat_prepare_to_resume (lp);
1646 linux_ops->to_resume (linux_ops,
1647 pid_to_ptid (ptid_get_lwp (lp->ptid)),
1651 lp->stopped_by_watchpoint = 0;
1655 if (debug_linux_nat)
1656 fprintf_unfiltered (gdb_stdlog,
1657 "RC: Not resuming sibling %s (has pending)\n",
1658 target_pid_to_str (lp->ptid));
1663 if (debug_linux_nat)
1664 fprintf_unfiltered (gdb_stdlog,
1665 "RC: Not resuming sibling %s (not stopped)\n",
1666 target_pid_to_str (lp->ptid));
1670 /* Resume LWP, with the last stop signal, if it is in pass state. */
1673 linux_nat_resume_callback (struct lwp_info *lp, void *data)
1675 enum gdb_signal signo = GDB_SIGNAL_0;
1679 struct thread_info *thread;
1681 thread = find_thread_ptid (lp->ptid);
1684 if (signal_pass_state (thread->suspend.stop_signal))
1685 signo = thread->suspend.stop_signal;
1686 thread->suspend.stop_signal = GDB_SIGNAL_0;
1690 resume_lwp (lp, 0, signo);
1695 resume_clear_callback (struct lwp_info *lp, void *data)
1698 lp->last_resume_kind = resume_stop;
1703 resume_set_callback (struct lwp_info *lp, void *data)
1706 lp->last_resume_kind = resume_continue;
1711 linux_nat_resume (struct target_ops *ops,
1712 ptid_t ptid, int step, enum gdb_signal signo)
1714 struct lwp_info *lp;
1717 if (debug_linux_nat)
1718 fprintf_unfiltered (gdb_stdlog,
1719 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1720 step ? "step" : "resume",
1721 target_pid_to_str (ptid),
1722 (signo != GDB_SIGNAL_0
1723 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1724 target_pid_to_str (inferior_ptid));
1726 /* A specific PTID means `step only this process id'. */
1727 resume_many = (ptid_equal (minus_one_ptid, ptid)
1728 || ptid_is_pid (ptid));
1730 /* Mark the lwps we're resuming as resumed. */
1731 iterate_over_lwps (ptid, resume_set_callback, NULL);
1733 /* See if it's the current inferior that should be handled
1736 lp = find_lwp_pid (inferior_ptid);
1738 lp = find_lwp_pid (ptid);
1739 gdb_assert (lp != NULL);
1741 /* Remember if we're stepping. */
1743 lp->last_resume_kind = step ? resume_step : resume_continue;
1745 /* If we have a pending wait status for this thread, there is no
1746 point in resuming the process. But first make sure that
1747 linux_nat_wait won't preemptively handle the event - we
1748 should never take this short-circuit if we are going to
1749 leave LP running, since we have skipped resuming all the
1750 other threads. This bit of code needs to be synchronized
1751 with linux_nat_wait. */
1753 if (lp->status && WIFSTOPPED (lp->status))
1756 && WSTOPSIG (lp->status)
1757 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1759 if (debug_linux_nat)
1760 fprintf_unfiltered (gdb_stdlog,
1761 "LLR: Not short circuiting for ignored "
1762 "status 0x%x\n", lp->status);
1764 /* FIXME: What should we do if we are supposed to continue
1765 this thread with a signal? */
1766 gdb_assert (signo == GDB_SIGNAL_0);
1767 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1772 if (lp->status || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1774 /* FIXME: What should we do if we are supposed to continue
1775 this thread with a signal? */
1776 gdb_assert (signo == GDB_SIGNAL_0);
1778 if (debug_linux_nat)
1779 fprintf_unfiltered (gdb_stdlog,
1780 "LLR: Short circuiting for status 0x%x\n",
1783 if (target_can_async_p ())
1785 target_async (inferior_event_handler, 0);
1786 /* Tell the event loop we have something to process. */
1792 /* Mark LWP as not stopped to prevent it from being continued by
1793 linux_nat_resume_callback. */
1797 iterate_over_lwps (ptid, linux_nat_resume_callback, NULL);
1799 /* Convert to something the lower layer understands. */
1800 ptid = pid_to_ptid (ptid_get_lwp (lp->ptid));
1802 if (linux_nat_prepare_to_resume != NULL)
1803 linux_nat_prepare_to_resume (lp);
1804 linux_ops->to_resume (linux_ops, ptid, step, signo);
1805 lp->stopped_by_watchpoint = 0;
1807 if (debug_linux_nat)
1808 fprintf_unfiltered (gdb_stdlog,
1809 "LLR: %s %s, %s (resume event thread)\n",
1810 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1811 target_pid_to_str (ptid),
1812 (signo != GDB_SIGNAL_0
1813 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1815 if (target_can_async_p ())
1816 target_async (inferior_event_handler, 0);
1819 /* Send a signal to an LWP. */
1822 kill_lwp (int lwpid, int signo)
1824 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1825 fails, then we are not using nptl threads and we should be using kill. */
1827 #ifdef HAVE_TKILL_SYSCALL
1829 static int tkill_failed;
1836 ret = syscall (__NR_tkill, lwpid, signo);
1837 if (errno != ENOSYS)
1844 return kill (lwpid, signo);
1847 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1848 event, check if the core is interested in it: if not, ignore the
1849 event, and keep waiting; otherwise, we need to toggle the LWP's
1850 syscall entry/exit status, since the ptrace event itself doesn't
1851 indicate it, and report the trap to higher layers. */
1854 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1856 struct target_waitstatus *ourstatus = &lp->waitstatus;
1857 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1858 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1862 /* If we're stopping threads, there's a SIGSTOP pending, which
1863 makes it so that the LWP reports an immediate syscall return,
1864 followed by the SIGSTOP. Skip seeing that "return" using
1865 PTRACE_CONT directly, and let stop_wait_callback collect the
1866 SIGSTOP. Later when the thread is resumed, a new syscall
1867 entry event. If we didn't do this (and returned 0), we'd
1868 leave a syscall entry pending, and our caller, by using
1869 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1870 itself. Later, when the user re-resumes this LWP, we'd see
1871 another syscall entry event and we'd mistake it for a return.
1873 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1874 (leaving immediately with LWP->signalled set, without issuing
1875 a PTRACE_CONT), it would still be problematic to leave this
1876 syscall enter pending, as later when the thread is resumed,
1877 it would then see the same syscall exit mentioned above,
1878 followed by the delayed SIGSTOP, while the syscall didn't
1879 actually get to execute. It seems it would be even more
1880 confusing to the user. */
1882 if (debug_linux_nat)
1883 fprintf_unfiltered (gdb_stdlog,
1884 "LHST: ignoring syscall %d "
1885 "for LWP %ld (stopping threads), "
1886 "resuming with PTRACE_CONT for SIGSTOP\n",
1888 ptid_get_lwp (lp->ptid));
1890 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1891 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1895 if (catch_syscall_enabled ())
1897 /* Always update the entry/return state, even if this particular
1898 syscall isn't interesting to the core now. In async mode,
1899 the user could install a new catchpoint for this syscall
1900 between syscall enter/return, and we'll need to know to
1901 report a syscall return if that happens. */
1902 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1903 ? TARGET_WAITKIND_SYSCALL_RETURN
1904 : TARGET_WAITKIND_SYSCALL_ENTRY);
1906 if (catching_syscall_number (syscall_number))
1908 /* Alright, an event to report. */
1909 ourstatus->kind = lp->syscall_state;
1910 ourstatus->value.syscall_number = syscall_number;
1912 if (debug_linux_nat)
1913 fprintf_unfiltered (gdb_stdlog,
1914 "LHST: stopping for %s of syscall %d"
1917 == TARGET_WAITKIND_SYSCALL_ENTRY
1918 ? "entry" : "return",
1920 ptid_get_lwp (lp->ptid));
1924 if (debug_linux_nat)
1925 fprintf_unfiltered (gdb_stdlog,
1926 "LHST: ignoring %s of syscall %d "
1928 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1929 ? "entry" : "return",
1931 ptid_get_lwp (lp->ptid));
1935 /* If we had been syscall tracing, and hence used PT_SYSCALL
1936 before on this LWP, it could happen that the user removes all
1937 syscall catchpoints before we get to process this event.
1938 There are two noteworthy issues here:
1940 - When stopped at a syscall entry event, resuming with
1941 PT_STEP still resumes executing the syscall and reports a
1944 - Only PT_SYSCALL catches syscall enters. If we last
1945 single-stepped this thread, then this event can't be a
1946 syscall enter. If we last single-stepped this thread, this
1947 has to be a syscall exit.
1949 The points above mean that the next resume, be it PT_STEP or
1950 PT_CONTINUE, can not trigger a syscall trace event. */
1951 if (debug_linux_nat)
1952 fprintf_unfiltered (gdb_stdlog,
1953 "LHST: caught syscall event "
1954 "with no syscall catchpoints."
1955 " %d for LWP %ld, ignoring\n",
1957 ptid_get_lwp (lp->ptid));
1958 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1961 /* The core isn't interested in this event. For efficiency, avoid
1962 stopping all threads only to have the core resume them all again.
1963 Since we're not stopping threads, if we're still syscall tracing
1964 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1965 subsequent syscall. Simply resume using the inf-ptrace layer,
1966 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1968 /* Note that gdbarch_get_syscall_number may access registers, hence
1970 registers_changed ();
1971 if (linux_nat_prepare_to_resume != NULL)
1972 linux_nat_prepare_to_resume (lp);
1973 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
1974 lp->step, GDB_SIGNAL_0);
1978 /* Handle a GNU/Linux extended wait response. If we see a clone
1979 event, we need to add the new LWP to our list (and not report the
1980 trap to higher layers). This function returns non-zero if the
1981 event should be ignored and we should wait again. If STOPPING is
1982 true, the new LWP remains stopped, otherwise it is continued. */
1985 linux_handle_extended_wait (struct lwp_info *lp, int status,
1988 int pid = ptid_get_lwp (lp->ptid);
1989 struct target_waitstatus *ourstatus = &lp->waitstatus;
1990 int event = status >> 16;
1992 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1993 || event == PTRACE_EVENT_CLONE)
1995 unsigned long new_pid;
1998 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
2000 /* If we haven't already seen the new PID stop, wait for it now. */
2001 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
2003 /* The new child has a pending SIGSTOP. We can't affect it until it
2004 hits the SIGSTOP, but we're already attached. */
2005 ret = my_waitpid (new_pid, &status,
2006 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
2008 perror_with_name (_("waiting for new child"));
2009 else if (ret != new_pid)
2010 internal_error (__FILE__, __LINE__,
2011 _("wait returned unexpected PID %d"), ret);
2012 else if (!WIFSTOPPED (status))
2013 internal_error (__FILE__, __LINE__,
2014 _("wait returned unexpected status 0x%x"), status);
2017 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
2019 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
2021 /* The arch-specific native code may need to know about new
2022 forks even if those end up never mapped to an
2024 if (linux_nat_new_fork != NULL)
2025 linux_nat_new_fork (lp, new_pid);
2028 if (event == PTRACE_EVENT_FORK
2029 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
2031 /* Handle checkpointing by linux-fork.c here as a special
2032 case. We don't want the follow-fork-mode or 'catch fork'
2033 to interfere with this. */
2035 /* This won't actually modify the breakpoint list, but will
2036 physically remove the breakpoints from the child. */
2037 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
2039 /* Retain child fork in ptrace (stopped) state. */
2040 if (!find_fork_pid (new_pid))
2043 /* Report as spurious, so that infrun doesn't want to follow
2044 this fork. We're actually doing an infcall in
2046 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
2048 /* Report the stop to the core. */
2052 if (event == PTRACE_EVENT_FORK)
2053 ourstatus->kind = TARGET_WAITKIND_FORKED;
2054 else if (event == PTRACE_EVENT_VFORK)
2055 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2058 struct lwp_info *new_lp;
2060 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2062 if (debug_linux_nat)
2063 fprintf_unfiltered (gdb_stdlog,
2064 "LHEW: Got clone event "
2065 "from LWP %d, new child is LWP %ld\n",
2068 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
2070 new_lp->stopped = 1;
2072 if (WSTOPSIG (status) != SIGSTOP)
2074 /* This can happen if someone starts sending signals to
2075 the new thread before it gets a chance to run, which
2076 have a lower number than SIGSTOP (e.g. SIGUSR1).
2077 This is an unlikely case, and harder to handle for
2078 fork / vfork than for clone, so we do not try - but
2079 we handle it for clone events here. We'll send
2080 the other signal on to the thread below. */
2082 new_lp->signalled = 1;
2086 struct thread_info *tp;
2088 /* When we stop for an event in some other thread, and
2089 pull the thread list just as this thread has cloned,
2090 we'll have seen the new thread in the thread_db list
2091 before handling the CLONE event (glibc's
2092 pthread_create adds the new thread to the thread list
2093 before clone'ing, and has the kernel fill in the
2094 thread's tid on the clone call with
2095 CLONE_PARENT_SETTID). If that happened, and the core
2096 had requested the new thread to stop, we'll have
2097 killed it with SIGSTOP. But since SIGSTOP is not an
2098 RT signal, it can only be queued once. We need to be
2099 careful to not resume the LWP if we wanted it to
2100 stop. In that case, we'll leave the SIGSTOP pending.
2101 It will later be reported as GDB_SIGNAL_0. */
2102 tp = find_thread_ptid (new_lp->ptid);
2103 if (tp != NULL && tp->stop_requested)
2104 new_lp->last_resume_kind = resume_stop;
2111 /* Add the new thread to GDB's lists as soon as possible
2114 1) the frontend doesn't have to wait for a stop to
2117 2) we tag it with the correct running state. */
2119 /* If the thread_db layer is active, let it know about
2120 this new thread, and add it to GDB's list. */
2121 if (!thread_db_attach_lwp (new_lp->ptid))
2123 /* We're not using thread_db. Add it to GDB's
2125 target_post_attach (ptid_get_lwp (new_lp->ptid));
2126 add_thread (new_lp->ptid);
2131 set_running (new_lp->ptid, 1);
2132 set_executing (new_lp->ptid, 1);
2133 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2135 new_lp->last_resume_kind = resume_continue;
2141 /* We created NEW_LP so it cannot yet contain STATUS. */
2142 gdb_assert (new_lp->status == 0);
2144 /* Save the wait status to report later. */
2145 if (debug_linux_nat)
2146 fprintf_unfiltered (gdb_stdlog,
2147 "LHEW: waitpid of new LWP %ld, "
2148 "saving status %s\n",
2149 (long) ptid_get_lwp (new_lp->ptid),
2150 status_to_str (status));
2151 new_lp->status = status;
2154 /* Note the need to use the low target ops to resume, to
2155 handle resuming with PT_SYSCALL if we have syscall
2159 new_lp->resumed = 1;
2163 gdb_assert (new_lp->last_resume_kind == resume_continue);
2164 if (debug_linux_nat)
2165 fprintf_unfiltered (gdb_stdlog,
2166 "LHEW: resuming new LWP %ld\n",
2167 ptid_get_lwp (new_lp->ptid));
2168 if (linux_nat_prepare_to_resume != NULL)
2169 linux_nat_prepare_to_resume (new_lp);
2170 linux_ops->to_resume (linux_ops, pid_to_ptid (new_pid),
2172 new_lp->stopped = 0;
2176 if (debug_linux_nat)
2177 fprintf_unfiltered (gdb_stdlog,
2178 "LHEW: resuming parent LWP %d\n", pid);
2179 if (linux_nat_prepare_to_resume != NULL)
2180 linux_nat_prepare_to_resume (lp);
2181 linux_ops->to_resume (linux_ops,
2182 pid_to_ptid (ptid_get_lwp (lp->ptid)),
2191 if (event == PTRACE_EVENT_EXEC)
2193 if (debug_linux_nat)
2194 fprintf_unfiltered (gdb_stdlog,
2195 "LHEW: Got exec event from LWP %ld\n",
2196 ptid_get_lwp (lp->ptid));
2198 ourstatus->kind = TARGET_WAITKIND_EXECD;
2199 ourstatus->value.execd_pathname
2200 = xstrdup (linux_child_pid_to_exec_file (pid));
2205 if (event == PTRACE_EVENT_VFORK_DONE)
2207 if (current_inferior ()->waiting_for_vfork_done)
2209 if (debug_linux_nat)
2210 fprintf_unfiltered (gdb_stdlog,
2211 "LHEW: Got expected PTRACE_EVENT_"
2212 "VFORK_DONE from LWP %ld: stopping\n",
2213 ptid_get_lwp (lp->ptid));
2215 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2219 if (debug_linux_nat)
2220 fprintf_unfiltered (gdb_stdlog,
2221 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2222 "from LWP %ld: resuming\n",
2223 ptid_get_lwp (lp->ptid));
2224 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2228 internal_error (__FILE__, __LINE__,
2229 _("unknown ptrace event %d"), event);
2232 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2236 wait_lwp (struct lwp_info *lp)
2240 int thread_dead = 0;
2243 gdb_assert (!lp->stopped);
2244 gdb_assert (lp->status == 0);
2246 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2247 block_child_signals (&prev_mask);
2251 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2252 was right and we should just call sigsuspend. */
2254 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2255 if (pid == -1 && errno == ECHILD)
2256 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2257 if (pid == -1 && errno == ECHILD)
2259 /* The thread has previously exited. We need to delete it
2260 now because, for some vendor 2.4 kernels with NPTL
2261 support backported, there won't be an exit event unless
2262 it is the main thread. 2.6 kernels will report an exit
2263 event for each thread that exits, as expected. */
2265 if (debug_linux_nat)
2266 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2267 target_pid_to_str (lp->ptid));
2272 /* Bugs 10970, 12702.
2273 Thread group leader may have exited in which case we'll lock up in
2274 waitpid if there are other threads, even if they are all zombies too.
2275 Basically, we're not supposed to use waitpid this way.
2276 __WCLONE is not applicable for the leader so we can't use that.
2277 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2278 process; it gets ESRCH both for the zombie and for running processes.
2280 As a workaround, check if we're waiting for the thread group leader and
2281 if it's a zombie, and avoid calling waitpid if it is.
2283 This is racy, what if the tgl becomes a zombie right after we check?
2284 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2285 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2287 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2288 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2291 if (debug_linux_nat)
2292 fprintf_unfiltered (gdb_stdlog,
2293 "WL: Thread group leader %s vanished.\n",
2294 target_pid_to_str (lp->ptid));
2298 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2299 get invoked despite our caller had them intentionally blocked by
2300 block_child_signals. This is sensitive only to the loop of
2301 linux_nat_wait_1 and there if we get called my_waitpid gets called
2302 again before it gets to sigsuspend so we can safely let the handlers
2303 get executed here. */
2305 sigsuspend (&suspend_mask);
2308 restore_child_signals_mask (&prev_mask);
2312 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2314 if (debug_linux_nat)
2316 fprintf_unfiltered (gdb_stdlog,
2317 "WL: waitpid %s received %s\n",
2318 target_pid_to_str (lp->ptid),
2319 status_to_str (status));
2322 /* Check if the thread has exited. */
2323 if (WIFEXITED (status) || WIFSIGNALED (status))
2326 if (debug_linux_nat)
2327 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2328 target_pid_to_str (lp->ptid));
2338 gdb_assert (WIFSTOPPED (status));
2340 /* Handle GNU/Linux's syscall SIGTRAPs. */
2341 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2343 /* No longer need the sysgood bit. The ptrace event ends up
2344 recorded in lp->waitstatus if we care for it. We can carry
2345 on handling the event like a regular SIGTRAP from here
2347 status = W_STOPCODE (SIGTRAP);
2348 if (linux_handle_syscall_trap (lp, 1))
2349 return wait_lwp (lp);
2352 /* Handle GNU/Linux's extended waitstatus for trace events. */
2353 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2355 if (debug_linux_nat)
2356 fprintf_unfiltered (gdb_stdlog,
2357 "WL: Handling extended status 0x%06x\n",
2359 if (linux_handle_extended_wait (lp, status, 1))
2360 return wait_lwp (lp);
2366 /* Send a SIGSTOP to LP. */
2369 stop_callback (struct lwp_info *lp, void *data)
2371 if (!lp->stopped && !lp->signalled)
2375 if (debug_linux_nat)
2377 fprintf_unfiltered (gdb_stdlog,
2378 "SC: kill %s **<SIGSTOP>**\n",
2379 target_pid_to_str (lp->ptid));
2382 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2383 if (debug_linux_nat)
2385 fprintf_unfiltered (gdb_stdlog,
2386 "SC: lwp kill %d %s\n",
2388 errno ? safe_strerror (errno) : "ERRNO-OK");
2392 gdb_assert (lp->status == 0);
2398 /* Request a stop on LWP. */
2401 linux_stop_lwp (struct lwp_info *lwp)
2403 stop_callback (lwp, NULL);
2406 /* Return non-zero if LWP PID has a pending SIGINT. */
2409 linux_nat_has_pending_sigint (int pid)
2411 sigset_t pending, blocked, ignored;
2413 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2415 if (sigismember (&pending, SIGINT)
2416 && !sigismember (&ignored, SIGINT))
2422 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2425 set_ignore_sigint (struct lwp_info *lp, void *data)
2427 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2428 flag to consume the next one. */
2429 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2430 && WSTOPSIG (lp->status) == SIGINT)
2433 lp->ignore_sigint = 1;
2438 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2439 This function is called after we know the LWP has stopped; if the LWP
2440 stopped before the expected SIGINT was delivered, then it will never have
2441 arrived. Also, if the signal was delivered to a shared queue and consumed
2442 by a different thread, it will never be delivered to this LWP. */
2445 maybe_clear_ignore_sigint (struct lwp_info *lp)
2447 if (!lp->ignore_sigint)
2450 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2452 if (debug_linux_nat)
2453 fprintf_unfiltered (gdb_stdlog,
2454 "MCIS: Clearing bogus flag for %s\n",
2455 target_pid_to_str (lp->ptid));
2456 lp->ignore_sigint = 0;
2460 /* Fetch the possible triggered data watchpoint info and store it in
2463 On some archs, like x86, that use debug registers to set
2464 watchpoints, it's possible that the way to know which watched
2465 address trapped, is to check the register that is used to select
2466 which address to watch. Problem is, between setting the watchpoint
2467 and reading back which data address trapped, the user may change
2468 the set of watchpoints, and, as a consequence, GDB changes the
2469 debug registers in the inferior. To avoid reading back a stale
2470 stopped-data-address when that happens, we cache in LP the fact
2471 that a watchpoint trapped, and the corresponding data address, as
2472 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2473 registers meanwhile, we have the cached data we can rely on. */
2476 save_sigtrap (struct lwp_info *lp)
2478 struct cleanup *old_chain;
2480 if (linux_ops->to_stopped_by_watchpoint == NULL)
2482 lp->stopped_by_watchpoint = 0;
2486 old_chain = save_inferior_ptid ();
2487 inferior_ptid = lp->ptid;
2489 lp->stopped_by_watchpoint = linux_ops->to_stopped_by_watchpoint ();
2491 if (lp->stopped_by_watchpoint)
2493 if (linux_ops->to_stopped_data_address != NULL)
2494 lp->stopped_data_address_p =
2495 linux_ops->to_stopped_data_address (¤t_target,
2496 &lp->stopped_data_address);
2498 lp->stopped_data_address_p = 0;
2501 do_cleanups (old_chain);
2504 /* See save_sigtrap. */
2507 linux_nat_stopped_by_watchpoint (void)
2509 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2511 gdb_assert (lp != NULL);
2513 return lp->stopped_by_watchpoint;
2517 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2519 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2521 gdb_assert (lp != NULL);
2523 *addr_p = lp->stopped_data_address;
2525 return lp->stopped_data_address_p;
2528 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2531 sigtrap_is_event (int status)
2533 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2536 /* SIGTRAP-like events recognizer. */
2538 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
2540 /* Check for SIGTRAP-like events in LP. */
2543 linux_nat_lp_status_is_event (struct lwp_info *lp)
2545 /* We check for lp->waitstatus in addition to lp->status, because we can
2546 have pending process exits recorded in lp->status
2547 and W_EXITCODE(0,0) == 0. We should probably have an additional
2548 lp->status_p flag. */
2550 return (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE
2551 && linux_nat_status_is_event (lp->status));
2554 /* Set alternative SIGTRAP-like events recognizer. If
2555 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2559 linux_nat_set_status_is_event (struct target_ops *t,
2560 int (*status_is_event) (int status))
2562 linux_nat_status_is_event = status_is_event;
2565 /* Wait until LP is stopped. */
2568 stop_wait_callback (struct lwp_info *lp, void *data)
2570 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2572 /* If this is a vfork parent, bail out, it is not going to report
2573 any SIGSTOP until the vfork is done with. */
2574 if (inf->vfork_child != NULL)
2581 status = wait_lwp (lp);
2585 if (lp->ignore_sigint && WIFSTOPPED (status)
2586 && WSTOPSIG (status) == SIGINT)
2588 lp->ignore_sigint = 0;
2591 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2592 if (debug_linux_nat)
2593 fprintf_unfiltered (gdb_stdlog,
2594 "PTRACE_CONT %s, 0, 0 (%s) "
2595 "(discarding SIGINT)\n",
2596 target_pid_to_str (lp->ptid),
2597 errno ? safe_strerror (errno) : "OK");
2599 return stop_wait_callback (lp, NULL);
2602 maybe_clear_ignore_sigint (lp);
2604 if (WSTOPSIG (status) != SIGSTOP)
2606 /* The thread was stopped with a signal other than SIGSTOP. */
2610 if (debug_linux_nat)
2611 fprintf_unfiltered (gdb_stdlog,
2612 "SWC: Pending event %s in %s\n",
2613 status_to_str ((int) status),
2614 target_pid_to_str (lp->ptid));
2616 /* Save the sigtrap event. */
2617 lp->status = status;
2618 gdb_assert (!lp->stopped);
2619 gdb_assert (lp->signalled);
2624 /* We caught the SIGSTOP that we intended to catch, so
2625 there's no SIGSTOP pending. */
2627 if (debug_linux_nat)
2628 fprintf_unfiltered (gdb_stdlog,
2629 "SWC: Delayed SIGSTOP caught for %s.\n",
2630 target_pid_to_str (lp->ptid));
2634 /* Reset SIGNALLED only after the stop_wait_callback call
2635 above as it does gdb_assert on SIGNALLED. */
2643 /* Return non-zero if LP has a wait status pending. */
2646 status_callback (struct lwp_info *lp, void *data)
2648 /* Only report a pending wait status if we pretend that this has
2649 indeed been resumed. */
2653 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2655 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2656 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2657 0', so a clean process exit can not be stored pending in
2658 lp->status, it is indistinguishable from
2659 no-pending-status. */
2663 if (lp->status != 0)
2669 /* Return non-zero if LP isn't stopped. */
2672 running_callback (struct lwp_info *lp, void *data)
2674 return (!lp->stopped
2675 || ((lp->status != 0
2676 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2680 /* Count the LWP's that have had events. */
2683 count_events_callback (struct lwp_info *lp, void *data)
2687 gdb_assert (count != NULL);
2689 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2690 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2696 /* Select the LWP (if any) that is currently being single-stepped. */
2699 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2701 if (lp->last_resume_kind == resume_step
2708 /* Select the Nth LWP that has had a SIGTRAP event. */
2711 select_event_lwp_callback (struct lwp_info *lp, void *data)
2713 int *selector = data;
2715 gdb_assert (selector != NULL);
2717 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2718 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2719 if ((*selector)-- == 0)
2726 cancel_breakpoint (struct lwp_info *lp)
2728 /* Arrange for a breakpoint to be hit again later. We don't keep
2729 the SIGTRAP status and don't forward the SIGTRAP signal to the
2730 LWP. We will handle the current event, eventually we will resume
2731 this LWP, and this breakpoint will trap again.
2733 If we do not do this, then we run the risk that the user will
2734 delete or disable the breakpoint, but the LWP will have already
2737 struct regcache *regcache = get_thread_regcache (lp->ptid);
2738 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2741 pc = regcache_read_pc (regcache) - gdbarch_decr_pc_after_break (gdbarch);
2742 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2744 if (debug_linux_nat)
2745 fprintf_unfiltered (gdb_stdlog,
2746 "CB: Push back breakpoint for %s\n",
2747 target_pid_to_str (lp->ptid));
2749 /* Back up the PC if necessary. */
2750 if (gdbarch_decr_pc_after_break (gdbarch))
2751 regcache_write_pc (regcache, pc);
2759 cancel_breakpoints_callback (struct lwp_info *lp, void *data)
2761 struct lwp_info *event_lp = data;
2763 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2767 /* If a LWP other than the LWP that we're reporting an event for has
2768 hit a GDB breakpoint (as opposed to some random trap signal),
2769 then just arrange for it to hit it again later. We don't keep
2770 the SIGTRAP status and don't forward the SIGTRAP signal to the
2771 LWP. We will handle the current event, eventually we will resume
2772 all LWPs, and this one will get its breakpoint trap again.
2774 If we do not do this, then we run the risk that the user will
2775 delete or disable the breakpoint, but the LWP will have already
2778 if (linux_nat_lp_status_is_event (lp)
2779 && cancel_breakpoint (lp))
2780 /* Throw away the SIGTRAP. */
2786 /* Select one LWP out of those that have events pending. */
2789 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2792 int random_selector;
2793 struct lwp_info *event_lp;
2795 /* Record the wait status for the original LWP. */
2796 (*orig_lp)->status = *status;
2798 /* Give preference to any LWP that is being single-stepped. */
2799 event_lp = iterate_over_lwps (filter,
2800 select_singlestep_lwp_callback, NULL);
2801 if (event_lp != NULL)
2803 if (debug_linux_nat)
2804 fprintf_unfiltered (gdb_stdlog,
2805 "SEL: Select single-step %s\n",
2806 target_pid_to_str (event_lp->ptid));
2810 /* No single-stepping LWP. Select one at random, out of those
2811 which have had SIGTRAP events. */
2813 /* First see how many SIGTRAP events we have. */
2814 iterate_over_lwps (filter, count_events_callback, &num_events);
2816 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2817 random_selector = (int)
2818 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2820 if (debug_linux_nat && num_events > 1)
2821 fprintf_unfiltered (gdb_stdlog,
2822 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2823 num_events, random_selector);
2825 event_lp = iterate_over_lwps (filter,
2826 select_event_lwp_callback,
2830 if (event_lp != NULL)
2832 /* Switch the event LWP. */
2833 *orig_lp = event_lp;
2834 *status = event_lp->status;
2837 /* Flush the wait status for the event LWP. */
2838 (*orig_lp)->status = 0;
2841 /* Return non-zero if LP has been resumed. */
2844 resumed_callback (struct lwp_info *lp, void *data)
2849 /* Stop an active thread, verify it still exists, then resume it. If
2850 the thread ends up with a pending status, then it is not resumed,
2851 and *DATA (really a pointer to int), is set. */
2854 stop_and_resume_callback (struct lwp_info *lp, void *data)
2856 int *new_pending_p = data;
2860 ptid_t ptid = lp->ptid;
2862 stop_callback (lp, NULL);
2863 stop_wait_callback (lp, NULL);
2865 /* Resume if the lwp still exists, and the core wanted it
2867 lp = find_lwp_pid (ptid);
2870 if (lp->last_resume_kind == resume_stop
2873 /* The core wanted the LWP to stop. Even if it stopped
2874 cleanly (with SIGSTOP), leave the event pending. */
2875 if (debug_linux_nat)
2876 fprintf_unfiltered (gdb_stdlog,
2877 "SARC: core wanted LWP %ld stopped "
2878 "(leaving SIGSTOP pending)\n",
2879 ptid_get_lwp (lp->ptid));
2880 lp->status = W_STOPCODE (SIGSTOP);
2883 if (lp->status == 0)
2885 if (debug_linux_nat)
2886 fprintf_unfiltered (gdb_stdlog,
2887 "SARC: re-resuming LWP %ld\n",
2888 ptid_get_lwp (lp->ptid));
2889 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2893 if (debug_linux_nat)
2894 fprintf_unfiltered (gdb_stdlog,
2895 "SARC: not re-resuming LWP %ld "
2897 ptid_get_lwp (lp->ptid));
2906 /* Check if we should go on and pass this event to common code.
2907 Return the affected lwp if we are, or NULL otherwise. If we stop
2908 all lwps temporarily, we may end up with new pending events in some
2909 other lwp. In that case set *NEW_PENDING_P to true. */
2911 static struct lwp_info *
2912 linux_nat_filter_event (int lwpid, int status, int *new_pending_p)
2914 struct lwp_info *lp;
2918 lp = find_lwp_pid (pid_to_ptid (lwpid));
2920 /* Check for stop events reported by a process we didn't already
2921 know about - anything not already in our LWP list.
2923 If we're expecting to receive stopped processes after
2924 fork, vfork, and clone events, then we'll just add the
2925 new one to our list and go back to waiting for the event
2926 to be reported - the stopped process might be returned
2927 from waitpid before or after the event is.
2929 But note the case of a non-leader thread exec'ing after the
2930 leader having exited, and gone from our lists. The non-leader
2931 thread changes its tid to the tgid. */
2933 if (WIFSTOPPED (status) && lp == NULL
2934 && (WSTOPSIG (status) == SIGTRAP && status >> 16 == PTRACE_EVENT_EXEC))
2936 /* A multi-thread exec after we had seen the leader exiting. */
2937 if (debug_linux_nat)
2938 fprintf_unfiltered (gdb_stdlog,
2939 "LLW: Re-adding thread group leader LWP %d.\n",
2942 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2945 add_thread (lp->ptid);
2948 if (WIFSTOPPED (status) && !lp)
2950 add_to_pid_list (&stopped_pids, lwpid, status);
2954 /* Make sure we don't report an event for the exit of an LWP not in
2955 our list, i.e. not part of the current process. This can happen
2956 if we detach from a program we originally forked and then it
2958 if (!WIFSTOPPED (status) && !lp)
2961 /* Handle GNU/Linux's syscall SIGTRAPs. */
2962 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2964 /* No longer need the sysgood bit. The ptrace event ends up
2965 recorded in lp->waitstatus if we care for it. We can carry
2966 on handling the event like a regular SIGTRAP from here
2968 status = W_STOPCODE (SIGTRAP);
2969 if (linux_handle_syscall_trap (lp, 0))
2973 /* Handle GNU/Linux's extended waitstatus for trace events. */
2974 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2976 if (debug_linux_nat)
2977 fprintf_unfiltered (gdb_stdlog,
2978 "LLW: Handling extended status 0x%06x\n",
2980 if (linux_handle_extended_wait (lp, status, 0))
2984 if (linux_nat_status_is_event (status))
2987 /* Check if the thread has exited. */
2988 if ((WIFEXITED (status) || WIFSIGNALED (status))
2989 && num_lwps (ptid_get_pid (lp->ptid)) > 1)
2991 /* If this is the main thread, we must stop all threads and verify
2992 if they are still alive. This is because in the nptl thread model
2993 on Linux 2.4, there is no signal issued for exiting LWPs
2994 other than the main thread. We only get the main thread exit
2995 signal once all child threads have already exited. If we
2996 stop all the threads and use the stop_wait_callback to check
2997 if they have exited we can determine whether this signal
2998 should be ignored or whether it means the end of the debugged
2999 application, regardless of which threading model is being
3001 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
3004 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3005 stop_and_resume_callback, new_pending_p);
3008 if (debug_linux_nat)
3009 fprintf_unfiltered (gdb_stdlog,
3010 "LLW: %s exited.\n",
3011 target_pid_to_str (lp->ptid));
3013 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3015 /* If there is at least one more LWP, then the exit signal
3016 was not the end of the debugged application and should be
3023 /* Check if the current LWP has previously exited. In the nptl
3024 thread model, LWPs other than the main thread do not issue
3025 signals when they exit so we must check whenever the thread has
3026 stopped. A similar check is made in stop_wait_callback(). */
3027 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3029 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3031 if (debug_linux_nat)
3032 fprintf_unfiltered (gdb_stdlog,
3033 "LLW: %s exited.\n",
3034 target_pid_to_str (lp->ptid));
3038 /* Make sure there is at least one thread running. */
3039 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3041 /* Discard the event. */
3045 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3046 an attempt to stop an LWP. */
3048 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3050 if (debug_linux_nat)
3051 fprintf_unfiltered (gdb_stdlog,
3052 "LLW: Delayed SIGSTOP caught for %s.\n",
3053 target_pid_to_str (lp->ptid));
3057 if (lp->last_resume_kind != resume_stop)
3059 /* This is a delayed SIGSTOP. */
3061 registers_changed ();
3063 if (linux_nat_prepare_to_resume != NULL)
3064 linux_nat_prepare_to_resume (lp);
3065 linux_ops->to_resume (linux_ops,
3066 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3067 lp->step, GDB_SIGNAL_0);
3068 if (debug_linux_nat)
3069 fprintf_unfiltered (gdb_stdlog,
3070 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3072 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3073 target_pid_to_str (lp->ptid));
3076 gdb_assert (lp->resumed);
3078 /* Discard the event. */
3083 /* Make sure we don't report a SIGINT that we have already displayed
3084 for another thread. */
3085 if (lp->ignore_sigint
3086 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3088 if (debug_linux_nat)
3089 fprintf_unfiltered (gdb_stdlog,
3090 "LLW: Delayed SIGINT caught for %s.\n",
3091 target_pid_to_str (lp->ptid));
3093 /* This is a delayed SIGINT. */
3094 lp->ignore_sigint = 0;
3096 registers_changed ();
3097 if (linux_nat_prepare_to_resume != NULL)
3098 linux_nat_prepare_to_resume (lp);
3099 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3100 lp->step, GDB_SIGNAL_0);
3101 if (debug_linux_nat)
3102 fprintf_unfiltered (gdb_stdlog,
3103 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3105 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3106 target_pid_to_str (lp->ptid));
3109 gdb_assert (lp->resumed);
3111 /* Discard the event. */
3115 /* An interesting event. */
3117 lp->status = status;
3121 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3122 their exits until all other threads in the group have exited. */
3125 check_zombie_leaders (void)
3127 struct inferior *inf;
3131 struct lwp_info *leader_lp;
3136 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3137 if (leader_lp != NULL
3138 /* Check if there are other threads in the group, as we may
3139 have raced with the inferior simply exiting. */
3140 && num_lwps (inf->pid) > 1
3141 && linux_proc_pid_is_zombie (inf->pid))
3143 if (debug_linux_nat)
3144 fprintf_unfiltered (gdb_stdlog,
3145 "CZL: Thread group leader %d zombie "
3146 "(it exited, or another thread execd).\n",
3149 /* A leader zombie can mean one of two things:
3151 - It exited, and there's an exit status pending
3152 available, or only the leader exited (not the whole
3153 program). In the latter case, we can't waitpid the
3154 leader's exit status until all other threads are gone.
3156 - There are 3 or more threads in the group, and a thread
3157 other than the leader exec'd. On an exec, the Linux
3158 kernel destroys all other threads (except the execing
3159 one) in the thread group, and resets the execing thread's
3160 tid to the tgid. No exit notification is sent for the
3161 execing thread -- from the ptracer's perspective, it
3162 appears as though the execing thread just vanishes.
3163 Until we reap all other threads except the leader and the
3164 execing thread, the leader will be zombie, and the
3165 execing thread will be in `D (disc sleep)'. As soon as
3166 all other threads are reaped, the execing thread changes
3167 it's tid to the tgid, and the previous (zombie) leader
3168 vanishes, giving place to the "new" leader. We could try
3169 distinguishing the exit and exec cases, by waiting once
3170 more, and seeing if something comes out, but it doesn't
3171 sound useful. The previous leader _does_ go away, and
3172 we'll re-add the new one once we see the exec event
3173 (which is just the same as what would happen if the
3174 previous leader did exit voluntarily before some other
3177 if (debug_linux_nat)
3178 fprintf_unfiltered (gdb_stdlog,
3179 "CZL: Thread group leader %d vanished.\n",
3181 exit_lwp (leader_lp);
3187 linux_nat_wait_1 (struct target_ops *ops,
3188 ptid_t ptid, struct target_waitstatus *ourstatus,
3191 static sigset_t prev_mask;
3192 enum resume_kind last_resume_kind;
3193 struct lwp_info *lp;
3196 if (debug_linux_nat)
3197 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3199 /* The first time we get here after starting a new inferior, we may
3200 not have added it to the LWP list yet - this is the earliest
3201 moment at which we know its PID. */
3202 if (ptid_is_pid (inferior_ptid))
3204 /* Upgrade the main thread's ptid. */
3205 thread_change_ptid (inferior_ptid,
3206 ptid_build (ptid_get_pid (inferior_ptid),
3207 ptid_get_pid (inferior_ptid), 0));
3209 lp = add_initial_lwp (inferior_ptid);
3213 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3214 block_child_signals (&prev_mask);
3220 /* First check if there is a LWP with a wait status pending. */
3221 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3223 /* Any LWP in the PTID group that's been resumed will do. */
3224 lp = iterate_over_lwps (ptid, status_callback, NULL);
3227 if (debug_linux_nat && lp->status)
3228 fprintf_unfiltered (gdb_stdlog,
3229 "LLW: Using pending wait status %s for %s.\n",
3230 status_to_str (lp->status),
3231 target_pid_to_str (lp->ptid));
3234 else if (ptid_lwp_p (ptid))
3236 if (debug_linux_nat)
3237 fprintf_unfiltered (gdb_stdlog,
3238 "LLW: Waiting for specific LWP %s.\n",
3239 target_pid_to_str (ptid));
3241 /* We have a specific LWP to check. */
3242 lp = find_lwp_pid (ptid);
3245 if (debug_linux_nat && lp->status)
3246 fprintf_unfiltered (gdb_stdlog,
3247 "LLW: Using pending wait status %s for %s.\n",
3248 status_to_str (lp->status),
3249 target_pid_to_str (lp->ptid));
3251 /* We check for lp->waitstatus in addition to lp->status,
3252 because we can have pending process exits recorded in
3253 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3254 an additional lp->status_p flag. */
3255 if (lp->status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3259 if (!target_can_async_p ())
3261 /* Causes SIGINT to be passed on to the attached process. */
3265 /* But if we don't find a pending event, we'll have to wait. */
3271 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3274 - If the thread group leader exits while other threads in the
3275 thread group still exist, waitpid(TGID, ...) hangs. That
3276 waitpid won't return an exit status until the other threads
3277 in the group are reapped.
3279 - When a non-leader thread execs, that thread just vanishes
3280 without reporting an exit (so we'd hang if we waited for it
3281 explicitly in that case). The exec event is reported to
3285 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3286 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3287 lwpid = my_waitpid (-1, &status, WNOHANG);
3289 if (debug_linux_nat)
3290 fprintf_unfiltered (gdb_stdlog,
3291 "LNW: waitpid(-1, ...) returned %d, %s\n",
3292 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3296 /* If this is true, then we paused LWPs momentarily, and may
3297 now have pending events to handle. */
3300 if (debug_linux_nat)
3302 fprintf_unfiltered (gdb_stdlog,
3303 "LLW: waitpid %ld received %s\n",
3304 (long) lwpid, status_to_str (status));
3307 lp = linux_nat_filter_event (lwpid, status, &new_pending);
3309 /* STATUS is now no longer valid, use LP->STATUS instead. */
3312 if (lp && !ptid_match (lp->ptid, ptid))
3314 gdb_assert (lp->resumed);
3316 if (debug_linux_nat)
3318 "LWP %ld got an event %06x, leaving pending.\n",
3319 ptid_get_lwp (lp->ptid), lp->status);
3321 if (WIFSTOPPED (lp->status))
3323 if (WSTOPSIG (lp->status) != SIGSTOP)
3325 /* Cancel breakpoint hits. The breakpoint may
3326 be removed before we fetch events from this
3327 process to report to the core. It is best
3328 not to assume the moribund breakpoints
3329 heuristic always handles these cases --- it
3330 could be too many events go through to the
3331 core before this one is handled. All-stop
3332 always cancels breakpoint hits in all
3335 && linux_nat_lp_status_is_event (lp)
3336 && cancel_breakpoint (lp))
3338 /* Throw away the SIGTRAP. */
3341 if (debug_linux_nat)
3343 "LLW: LWP %ld hit a breakpoint while"
3344 " waiting for another process;"
3346 ptid_get_lwp (lp->ptid));
3356 else if (WIFEXITED (lp->status) || WIFSIGNALED (lp->status))
3358 if (debug_linux_nat)
3360 "Process %ld exited while stopping LWPs\n",
3361 ptid_get_lwp (lp->ptid));
3363 /* This was the last lwp in the process. Since
3364 events are serialized to GDB core, and we can't
3365 report this one right now, but GDB core and the
3366 other target layers will want to be notified
3367 about the exit code/signal, leave the status
3368 pending for the next time we're able to report
3371 /* Prevent trying to stop this thread again. We'll
3372 never try to resume it because it has a pending
3376 /* Dead LWP's aren't expected to reported a pending
3380 /* Store the pending event in the waitstatus as
3381 well, because W_EXITCODE(0,0) == 0. */
3382 store_waitstatus (&lp->waitstatus, lp->status);
3391 /* Some LWP now has a pending event. Go all the way
3392 back to check it. */
3398 /* We got an event to report to the core. */
3402 /* Retry until nothing comes out of waitpid. A single
3403 SIGCHLD can indicate more than one child stopped. */
3407 /* Check for zombie thread group leaders. Those can't be reaped
3408 until all other threads in the thread group are. */
3409 check_zombie_leaders ();
3411 /* If there are no resumed children left, bail. We'd be stuck
3412 forever in the sigsuspend call below otherwise. */
3413 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3415 if (debug_linux_nat)
3416 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3418 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3420 if (!target_can_async_p ())
3421 clear_sigint_trap ();
3423 restore_child_signals_mask (&prev_mask);
3424 return minus_one_ptid;
3427 /* No interesting event to report to the core. */
3429 if (target_options & TARGET_WNOHANG)
3431 if (debug_linux_nat)
3432 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3434 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3435 restore_child_signals_mask (&prev_mask);
3436 return minus_one_ptid;
3439 /* We shouldn't end up here unless we want to try again. */
3440 gdb_assert (lp == NULL);
3442 /* Block until we get an event reported with SIGCHLD. */
3443 sigsuspend (&suspend_mask);
3446 if (!target_can_async_p ())
3447 clear_sigint_trap ();
3451 status = lp->status;
3454 /* Don't report signals that GDB isn't interested in, such as
3455 signals that are neither printed nor stopped upon. Stopping all
3456 threads can be a bit time-consuming so if we want decent
3457 performance with heavily multi-threaded programs, especially when
3458 they're using a high frequency timer, we'd better avoid it if we
3461 if (WIFSTOPPED (status))
3463 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3465 /* When using hardware single-step, we need to report every signal.
3466 Otherwise, signals in pass_mask may be short-circuited. */
3468 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status)))
3470 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3471 here? It is not clear we should. GDB may not expect
3472 other threads to run. On the other hand, not resuming
3473 newly attached threads may cause an unwanted delay in
3474 getting them running. */
3475 registers_changed ();
3476 if (linux_nat_prepare_to_resume != NULL)
3477 linux_nat_prepare_to_resume (lp);
3478 linux_ops->to_resume (linux_ops,
3479 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3481 if (debug_linux_nat)
3482 fprintf_unfiltered (gdb_stdlog,
3483 "LLW: %s %s, %s (preempt 'handle')\n",
3485 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3486 target_pid_to_str (lp->ptid),
3487 (signo != GDB_SIGNAL_0
3488 ? strsignal (gdb_signal_to_host (signo))
3496 /* Only do the below in all-stop, as we currently use SIGINT
3497 to implement target_stop (see linux_nat_stop) in
3499 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3501 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3502 forwarded to the entire process group, that is, all LWPs
3503 will receive it - unless they're using CLONE_THREAD to
3504 share signals. Since we only want to report it once, we
3505 mark it as ignored for all LWPs except this one. */
3506 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)),
3507 set_ignore_sigint, NULL);
3508 lp->ignore_sigint = 0;
3511 maybe_clear_ignore_sigint (lp);
3515 /* This LWP is stopped now. */
3518 if (debug_linux_nat)
3519 fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
3520 status_to_str (status), target_pid_to_str (lp->ptid));
3524 /* Now stop all other LWP's ... */
3525 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3527 /* ... and wait until all of them have reported back that
3528 they're no longer running. */
3529 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3531 /* If we're not waiting for a specific LWP, choose an event LWP
3532 from among those that have had events. Giving equal priority
3533 to all LWPs that have had events helps prevent
3535 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3536 select_event_lwp (ptid, &lp, &status);
3538 /* Now that we've selected our final event LWP, cancel any
3539 breakpoints in other LWPs that have hit a GDB breakpoint.
3540 See the comment in cancel_breakpoints_callback to find out
3542 iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp);
3544 /* We'll need this to determine whether to report a SIGSTOP as
3545 TARGET_WAITKIND_0. Need to take a copy because
3546 resume_clear_callback clears it. */
3547 last_resume_kind = lp->last_resume_kind;
3549 /* In all-stop, from the core's perspective, all LWPs are now
3550 stopped until a new resume action is sent over. */
3551 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3556 last_resume_kind = lp->last_resume_kind;
3557 resume_clear_callback (lp, NULL);
3560 if (linux_nat_status_is_event (status))
3562 if (debug_linux_nat)
3563 fprintf_unfiltered (gdb_stdlog,
3564 "LLW: trap ptid is %s.\n",
3565 target_pid_to_str (lp->ptid));
3568 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3570 *ourstatus = lp->waitstatus;
3571 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3574 store_waitstatus (ourstatus, status);
3576 if (debug_linux_nat)
3577 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3579 restore_child_signals_mask (&prev_mask);
3581 if (last_resume_kind == resume_stop
3582 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3583 && WSTOPSIG (status) == SIGSTOP)
3585 /* A thread that has been requested to stop by GDB with
3586 target_stop, and it stopped cleanly, so report as SIG0. The
3587 use of SIGSTOP is an implementation detail. */
3588 ourstatus->value.sig = GDB_SIGNAL_0;
3591 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3592 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3595 lp->core = linux_common_core_of_thread (lp->ptid);
3600 /* Resume LWPs that are currently stopped without any pending status
3601 to report, but are resumed from the core's perspective. */
3604 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3606 ptid_t *wait_ptid_p = data;
3611 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3613 struct regcache *regcache = get_thread_regcache (lp->ptid);
3614 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3615 CORE_ADDR pc = regcache_read_pc (regcache);
3617 gdb_assert (is_executing (lp->ptid));
3619 /* Don't bother if there's a breakpoint at PC that we'd hit
3620 immediately, and we're not waiting for this LWP. */
3621 if (!ptid_match (lp->ptid, *wait_ptid_p))
3623 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3627 if (debug_linux_nat)
3628 fprintf_unfiltered (gdb_stdlog,
3629 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3630 target_pid_to_str (lp->ptid),
3631 paddress (gdbarch, pc),
3634 registers_changed ();
3635 if (linux_nat_prepare_to_resume != NULL)
3636 linux_nat_prepare_to_resume (lp);
3637 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3638 lp->step, GDB_SIGNAL_0);
3640 lp->stopped_by_watchpoint = 0;
3647 linux_nat_wait (struct target_ops *ops,
3648 ptid_t ptid, struct target_waitstatus *ourstatus,
3653 if (debug_linux_nat)
3655 char *options_string;
3657 options_string = target_options_to_string (target_options);
3658 fprintf_unfiltered (gdb_stdlog,
3659 "linux_nat_wait: [%s], [%s]\n",
3660 target_pid_to_str (ptid),
3662 xfree (options_string);
3665 /* Flush the async file first. */
3666 if (target_can_async_p ())
3667 async_file_flush ();
3669 /* Resume LWPs that are currently stopped without any pending status
3670 to report, but are resumed from the core's perspective. LWPs get
3671 in this state if we find them stopping at a time we're not
3672 interested in reporting the event (target_wait on a
3673 specific_process, for example, see linux_nat_wait_1), and
3674 meanwhile the event became uninteresting. Don't bother resuming
3675 LWPs we're not going to wait for if they'd stop immediately. */
3677 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3679 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3681 /* If we requested any event, and something came out, assume there
3682 may be more. If we requested a specific lwp or process, also
3683 assume there may be more. */
3684 if (target_can_async_p ()
3685 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3686 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3687 || !ptid_equal (ptid, minus_one_ptid)))
3690 /* Get ready for the next event. */
3691 if (target_can_async_p ())
3692 target_async (inferior_event_handler, 0);
3698 kill_callback (struct lwp_info *lp, void *data)
3700 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3703 kill (ptid_get_lwp (lp->ptid), SIGKILL);
3704 if (debug_linux_nat)
3705 fprintf_unfiltered (gdb_stdlog,
3706 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3707 target_pid_to_str (lp->ptid),
3708 errno ? safe_strerror (errno) : "OK");
3710 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3713 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3714 if (debug_linux_nat)
3715 fprintf_unfiltered (gdb_stdlog,
3716 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3717 target_pid_to_str (lp->ptid),
3718 errno ? safe_strerror (errno) : "OK");
3724 kill_wait_callback (struct lwp_info *lp, void *data)
3728 /* We must make sure that there are no pending events (delayed
3729 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3730 program doesn't interfere with any following debugging session. */
3732 /* For cloned processes we must check both with __WCLONE and
3733 without, since the exit status of a cloned process isn't reported
3739 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3740 if (pid != (pid_t) -1)
3742 if (debug_linux_nat)
3743 fprintf_unfiltered (gdb_stdlog,
3744 "KWC: wait %s received unknown.\n",
3745 target_pid_to_str (lp->ptid));
3746 /* The Linux kernel sometimes fails to kill a thread
3747 completely after PTRACE_KILL; that goes from the stop
3748 point in do_fork out to the one in
3749 get_signal_to_deliever and waits again. So kill it
3751 kill_callback (lp, NULL);
3754 while (pid == ptid_get_lwp (lp->ptid));
3756 gdb_assert (pid == -1 && errno == ECHILD);
3761 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3762 if (pid != (pid_t) -1)
3764 if (debug_linux_nat)
3765 fprintf_unfiltered (gdb_stdlog,
3766 "KWC: wait %s received unk.\n",
3767 target_pid_to_str (lp->ptid));
3768 /* See the call to kill_callback above. */
3769 kill_callback (lp, NULL);
3772 while (pid == ptid_get_lwp (lp->ptid));
3774 gdb_assert (pid == -1 && errno == ECHILD);
3779 linux_nat_kill (struct target_ops *ops)
3781 struct target_waitstatus last;
3785 /* If we're stopped while forking and we haven't followed yet,
3786 kill the other task. We need to do this first because the
3787 parent will be sleeping if this is a vfork. */
3789 get_last_target_status (&last_ptid, &last);
3791 if (last.kind == TARGET_WAITKIND_FORKED
3792 || last.kind == TARGET_WAITKIND_VFORKED)
3794 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3797 /* Let the arch-specific native code know this process is
3799 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3802 if (forks_exist_p ())
3803 linux_fork_killall ();
3806 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3808 /* Stop all threads before killing them, since ptrace requires
3809 that the thread is stopped to sucessfully PTRACE_KILL. */
3810 iterate_over_lwps (ptid, stop_callback, NULL);
3811 /* ... and wait until all of them have reported back that
3812 they're no longer running. */
3813 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3815 /* Kill all LWP's ... */
3816 iterate_over_lwps (ptid, kill_callback, NULL);
3818 /* ... and wait until we've flushed all events. */
3819 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3822 target_mourn_inferior ();
3826 linux_nat_mourn_inferior (struct target_ops *ops)
3828 int pid = ptid_get_pid (inferior_ptid);
3830 purge_lwp_list (pid);
3832 if (! forks_exist_p ())
3833 /* Normal case, no other forks available. */
3834 linux_ops->to_mourn_inferior (ops);
3836 /* Multi-fork case. The current inferior_ptid has exited, but
3837 there are other viable forks to debug. Delete the exiting
3838 one and context-switch to the first available. */
3839 linux_fork_mourn_inferior ();
3841 /* Let the arch-specific native code know this process is gone. */
3842 linux_nat_forget_process (pid);
3845 /* Convert a native/host siginfo object, into/from the siginfo in the
3846 layout of the inferiors' architecture. */
3849 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3853 if (linux_nat_siginfo_fixup != NULL)
3854 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3856 /* If there was no callback, or the callback didn't do anything,
3857 then just do a straight memcpy. */
3861 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3863 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3868 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3869 const char *annex, gdb_byte *readbuf,
3870 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
3874 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3876 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3877 gdb_assert (readbuf || writebuf);
3879 pid = ptid_get_lwp (inferior_ptid);
3881 pid = ptid_get_pid (inferior_ptid);
3883 if (offset > sizeof (siginfo))
3887 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3891 /* When GDB is built as a 64-bit application, ptrace writes into
3892 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3893 inferior with a 64-bit GDB should look the same as debugging it
3894 with a 32-bit GDB, we need to convert it. GDB core always sees
3895 the converted layout, so any read/write will have to be done
3897 siginfo_fixup (&siginfo, inf_siginfo, 0);
3899 if (offset + len > sizeof (siginfo))
3900 len = sizeof (siginfo) - offset;
3902 if (readbuf != NULL)
3903 memcpy (readbuf, inf_siginfo + offset, len);
3906 memcpy (inf_siginfo + offset, writebuf, len);
3908 /* Convert back to ptrace layout before flushing it out. */
3909 siginfo_fixup (&siginfo, inf_siginfo, 1);
3912 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3921 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3922 const char *annex, gdb_byte *readbuf,
3923 const gdb_byte *writebuf,
3924 ULONGEST offset, LONGEST len)
3926 struct cleanup *old_chain;
3929 if (object == TARGET_OBJECT_SIGNAL_INFO)
3930 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3933 /* The target is connected but no live inferior is selected. Pass
3934 this request down to a lower stratum (e.g., the executable
3936 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3939 old_chain = save_inferior_ptid ();
3941 if (ptid_lwp_p (inferior_ptid))
3942 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3944 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3947 do_cleanups (old_chain);
3952 linux_thread_alive (ptid_t ptid)
3956 gdb_assert (ptid_lwp_p (ptid));
3958 /* Send signal 0 instead of anything ptrace, because ptracing a
3959 running thread errors out claiming that the thread doesn't
3961 err = kill_lwp (ptid_get_lwp (ptid), 0);
3963 if (debug_linux_nat)
3964 fprintf_unfiltered (gdb_stdlog,
3965 "LLTA: KILL(SIG0) %s (%s)\n",
3966 target_pid_to_str (ptid),
3967 err ? safe_strerror (tmp_errno) : "OK");
3976 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3978 return linux_thread_alive (ptid);
3982 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3984 static char buf[64];
3986 if (ptid_lwp_p (ptid)
3987 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
3988 || num_lwps (ptid_get_pid (ptid)) > 1))
3990 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
3994 return normal_pid_to_str (ptid);
3998 linux_nat_thread_name (struct thread_info *thr)
4000 int pid = ptid_get_pid (thr->ptid);
4001 long lwp = ptid_get_lwp (thr->ptid);
4002 #define FORMAT "/proc/%d/task/%ld/comm"
4003 char buf[sizeof (FORMAT) + 30];
4005 char *result = NULL;
4007 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
4008 comm_file = gdb_fopen_cloexec (buf, "r");
4011 /* Not exported by the kernel, so we define it here. */
4013 static char line[COMM_LEN + 1];
4015 if (fgets (line, sizeof (line), comm_file))
4017 char *nl = strchr (line, '\n');
4034 /* Accepts an integer PID; Returns a string representing a file that
4035 can be opened to get the symbols for the child process. */
4038 linux_child_pid_to_exec_file (int pid)
4040 char *name1, *name2;
4042 name1 = xmalloc (PATH_MAX);
4043 name2 = xmalloc (PATH_MAX);
4044 make_cleanup (xfree, name1);
4045 make_cleanup (xfree, name2);
4046 memset (name2, 0, PATH_MAX);
4048 xsnprintf (name1, PATH_MAX, "/proc/%d/exe", pid);
4049 if (readlink (name1, name2, PATH_MAX - 1) > 0)
4055 /* Records the thread's register state for the corefile note
4059 linux_nat_collect_thread_registers (const struct regcache *regcache,
4060 ptid_t ptid, bfd *obfd,
4061 char *note_data, int *note_size,
4062 enum gdb_signal stop_signal)
4064 struct gdbarch *gdbarch = get_regcache_arch (regcache);
4065 const struct regset *regset;
4067 gdb_gregset_t gregs;
4068 gdb_fpregset_t fpregs;
4070 core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
4073 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
4075 != NULL && regset->collect_regset != NULL)
4076 regset->collect_regset (regset, regcache, -1, &gregs, sizeof (gregs));
4078 fill_gregset (regcache, &gregs, -1);
4080 note_data = (char *) elfcore_write_prstatus
4081 (obfd, note_data, note_size, ptid_get_lwp (ptid),
4082 gdb_signal_to_host (stop_signal), &gregs);
4085 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
4087 != NULL && regset->collect_regset != NULL)
4088 regset->collect_regset (regset, regcache, -1, &fpregs, sizeof (fpregs));
4090 fill_fpregset (regcache, &fpregs, -1);
4092 note_data = (char *) elfcore_write_prfpreg (obfd, note_data, note_size,
4093 &fpregs, sizeof (fpregs));
4098 /* Fills the "to_make_corefile_note" target vector. Builds the note
4099 section for a corefile, and returns it in a malloc buffer. */
4102 linux_nat_make_corefile_notes (bfd *obfd, int *note_size)
4104 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4105 converted to gdbarch_core_regset_sections, this function can go away. */
4106 return linux_make_corefile_notes (target_gdbarch (), obfd, note_size,
4107 linux_nat_collect_thread_registers);
4110 /* Implement the to_xfer_partial interface for memory reads using the /proc
4111 filesystem. Because we can use a single read() call for /proc, this
4112 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4113 but it doesn't support writes. */
4116 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4117 const char *annex, gdb_byte *readbuf,
4118 const gdb_byte *writebuf,
4119 ULONGEST offset, LONGEST len)
4125 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4128 /* Don't bother for one word. */
4129 if (len < 3 * sizeof (long))
4132 /* We could keep this file open and cache it - possibly one per
4133 thread. That requires some juggling, but is even faster. */
4134 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
4135 ptid_get_pid (inferior_ptid));
4136 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
4140 /* If pread64 is available, use it. It's faster if the kernel
4141 supports it (only one syscall), and it's 64-bit safe even on
4142 32-bit platforms (for instance, SPARC debugging a SPARC64
4145 if (pread64 (fd, readbuf, len, offset) != len)
4147 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4158 /* Enumerate spufs IDs for process PID. */
4160 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, LONGEST len)
4162 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4164 LONGEST written = 0;
4167 struct dirent *entry;
4169 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4170 dir = opendir (path);
4175 while ((entry = readdir (dir)) != NULL)
4181 fd = atoi (entry->d_name);
4185 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4186 if (stat (path, &st) != 0)
4188 if (!S_ISDIR (st.st_mode))
4191 if (statfs (path, &stfs) != 0)
4193 if (stfs.f_type != SPUFS_MAGIC)
4196 if (pos >= offset && pos + 4 <= offset + len)
4198 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4208 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4209 object type, using the /proc file system. */
4211 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4212 const char *annex, gdb_byte *readbuf,
4213 const gdb_byte *writebuf,
4214 ULONGEST offset, LONGEST len)
4219 int pid = ptid_get_pid (inferior_ptid);
4226 return spu_enumerate_spu_ids (pid, readbuf, offset, len);
4229 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4230 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4235 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4242 ret = write (fd, writebuf, (size_t) len);
4244 ret = read (fd, readbuf, (size_t) len);
4251 /* Parse LINE as a signal set and add its set bits to SIGS. */
4254 add_line_to_sigset (const char *line, sigset_t *sigs)
4256 int len = strlen (line) - 1;
4260 if (line[len] != '\n')
4261 error (_("Could not parse signal set: %s"), line);
4269 if (*p >= '0' && *p <= '9')
4271 else if (*p >= 'a' && *p <= 'f')
4272 digit = *p - 'a' + 10;
4274 error (_("Could not parse signal set: %s"), line);
4279 sigaddset (sigs, signum + 1);
4281 sigaddset (sigs, signum + 2);
4283 sigaddset (sigs, signum + 3);
4285 sigaddset (sigs, signum + 4);
4291 /* Find process PID's pending signals from /proc/pid/status and set
4295 linux_proc_pending_signals (int pid, sigset_t *pending,
4296 sigset_t *blocked, sigset_t *ignored)
4299 char buffer[PATH_MAX], fname[PATH_MAX];
4300 struct cleanup *cleanup;
4302 sigemptyset (pending);
4303 sigemptyset (blocked);
4304 sigemptyset (ignored);
4305 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4306 procfile = gdb_fopen_cloexec (fname, "r");
4307 if (procfile == NULL)
4308 error (_("Could not open %s"), fname);
4309 cleanup = make_cleanup_fclose (procfile);
4311 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4313 /* Normal queued signals are on the SigPnd line in the status
4314 file. However, 2.6 kernels also have a "shared" pending
4315 queue for delivering signals to a thread group, so check for
4318 Unfortunately some Red Hat kernels include the shared pending
4319 queue but not the ShdPnd status field. */
4321 if (strncmp (buffer, "SigPnd:\t", 8) == 0)
4322 add_line_to_sigset (buffer + 8, pending);
4323 else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
4324 add_line_to_sigset (buffer + 8, pending);
4325 else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
4326 add_line_to_sigset (buffer + 8, blocked);
4327 else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
4328 add_line_to_sigset (buffer + 8, ignored);
4331 do_cleanups (cleanup);
4335 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4336 const char *annex, gdb_byte *readbuf,
4337 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
4339 gdb_assert (object == TARGET_OBJECT_OSDATA);
4341 return linux_common_xfer_osdata (annex, readbuf, offset, len);
4345 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4346 const char *annex, gdb_byte *readbuf,
4347 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
4351 if (object == TARGET_OBJECT_AUXV)
4352 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4355 if (object == TARGET_OBJECT_OSDATA)
4356 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4359 if (object == TARGET_OBJECT_SPU)
4360 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4363 /* GDB calculates all the addresses in possibly larget width of the address.
4364 Address width needs to be masked before its final use - either by
4365 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4367 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4369 if (object == TARGET_OBJECT_MEMORY)
4371 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4373 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4374 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4377 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4382 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4387 cleanup_target_stop (void *arg)
4389 ptid_t *ptid = (ptid_t *) arg;
4391 gdb_assert (arg != NULL);
4394 target_resume (*ptid, 0, GDB_SIGNAL_0);
4397 static VEC(static_tracepoint_marker_p) *
4398 linux_child_static_tracepoint_markers_by_strid (const char *strid)
4400 char s[IPA_CMD_BUF_SIZE];
4401 struct cleanup *old_chain;
4402 int pid = ptid_get_pid (inferior_ptid);
4403 VEC(static_tracepoint_marker_p) *markers = NULL;
4404 struct static_tracepoint_marker *marker = NULL;
4406 ptid_t ptid = ptid_build (pid, 0, 0);
4411 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4412 s[sizeof ("qTfSTM")] = 0;
4414 agent_run_command (pid, s, strlen (s) + 1);
4416 old_chain = make_cleanup (free_current_marker, &marker);
4417 make_cleanup (cleanup_target_stop, &ptid);
4422 marker = XCNEW (struct static_tracepoint_marker);
4426 parse_static_tracepoint_marker_definition (p, &p, marker);
4428 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4430 VEC_safe_push (static_tracepoint_marker_p,
4436 release_static_tracepoint_marker (marker);
4437 memset (marker, 0, sizeof (*marker));
4440 while (*p++ == ','); /* comma-separated list */
4442 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4443 s[sizeof ("qTsSTM")] = 0;
4444 agent_run_command (pid, s, strlen (s) + 1);
4448 do_cleanups (old_chain);
4453 /* Create a prototype generic GNU/Linux target. The client can override
4454 it with local methods. */
4457 linux_target_install_ops (struct target_ops *t)
4459 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4460 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4461 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4462 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4463 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4464 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4465 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4466 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4467 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4468 t->to_post_attach = linux_child_post_attach;
4469 t->to_follow_fork = linux_child_follow_fork;
4470 t->to_make_corefile_notes = linux_nat_make_corefile_notes;
4472 super_xfer_partial = t->to_xfer_partial;
4473 t->to_xfer_partial = linux_xfer_partial;
4475 t->to_static_tracepoint_markers_by_strid
4476 = linux_child_static_tracepoint_markers_by_strid;
4482 struct target_ops *t;
4484 t = inf_ptrace_target ();
4485 linux_target_install_ops (t);
4491 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4493 struct target_ops *t;
4495 t = inf_ptrace_trad_target (register_u_offset);
4496 linux_target_install_ops (t);
4501 /* target_is_async_p implementation. */
4504 linux_nat_is_async_p (void)
4506 /* NOTE: palves 2008-03-21: We're only async when the user requests
4507 it explicitly with the "set target-async" command.
4508 Someday, linux will always be async. */
4509 return target_async_permitted;
4512 /* target_can_async_p implementation. */
4515 linux_nat_can_async_p (void)
4517 /* NOTE: palves 2008-03-21: We're only async when the user requests
4518 it explicitly with the "set target-async" command.
4519 Someday, linux will always be async. */
4520 return target_async_permitted;
4524 linux_nat_supports_non_stop (void)
4529 /* True if we want to support multi-process. To be removed when GDB
4530 supports multi-exec. */
4532 int linux_multi_process = 1;
4535 linux_nat_supports_multi_process (void)
4537 return linux_multi_process;
4541 linux_nat_supports_disable_randomization (void)
4543 #ifdef HAVE_PERSONALITY
4550 static int async_terminal_is_ours = 1;
4552 /* target_terminal_inferior implementation. */
4555 linux_nat_terminal_inferior (void)
4557 if (!target_is_async_p ())
4559 /* Async mode is disabled. */
4560 terminal_inferior ();
4564 terminal_inferior ();
4566 /* Calls to target_terminal_*() are meant to be idempotent. */
4567 if (!async_terminal_is_ours)
4570 delete_file_handler (input_fd);
4571 async_terminal_is_ours = 0;
4575 /* target_terminal_ours implementation. */
4578 linux_nat_terminal_ours (void)
4580 if (!target_is_async_p ())
4582 /* Async mode is disabled. */
4587 /* GDB should never give the terminal to the inferior if the
4588 inferior is running in the background (run&, continue&, etc.),
4589 but claiming it sure should. */
4592 if (async_terminal_is_ours)
4595 clear_sigint_trap ();
4596 add_file_handler (input_fd, stdin_event_handler, 0);
4597 async_terminal_is_ours = 1;
4600 static void (*async_client_callback) (enum inferior_event_type event_type,
4602 static void *async_client_context;
4604 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4605 so we notice when any child changes state, and notify the
4606 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4607 above to wait for the arrival of a SIGCHLD. */
4610 sigchld_handler (int signo)
4612 int old_errno = errno;
4614 if (debug_linux_nat)
4615 ui_file_write_async_safe (gdb_stdlog,
4616 "sigchld\n", sizeof ("sigchld\n") - 1);
4618 if (signo == SIGCHLD
4619 && linux_nat_event_pipe[0] != -1)
4620 async_file_mark (); /* Let the event loop know that there are
4621 events to handle. */
4626 /* Callback registered with the target events file descriptor. */
4629 handle_target_event (int error, gdb_client_data client_data)
4631 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4634 /* Create/destroy the target events pipe. Returns previous state. */
4637 linux_async_pipe (int enable)
4639 int previous = (linux_nat_event_pipe[0] != -1);
4641 if (previous != enable)
4645 /* Block child signals while we create/destroy the pipe, as
4646 their handler writes to it. */
4647 block_child_signals (&prev_mask);
4651 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4652 internal_error (__FILE__, __LINE__,
4653 "creating event pipe failed.");
4655 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4656 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4660 close (linux_nat_event_pipe[0]);
4661 close (linux_nat_event_pipe[1]);
4662 linux_nat_event_pipe[0] = -1;
4663 linux_nat_event_pipe[1] = -1;
4666 restore_child_signals_mask (&prev_mask);
4672 /* target_async implementation. */
4675 linux_nat_async (void (*callback) (enum inferior_event_type event_type,
4676 void *context), void *context)
4678 if (callback != NULL)
4680 async_client_callback = callback;
4681 async_client_context = context;
4682 if (!linux_async_pipe (1))
4684 add_file_handler (linux_nat_event_pipe[0],
4685 handle_target_event, NULL);
4686 /* There may be pending events to handle. Tell the event loop
4693 async_client_callback = callback;
4694 async_client_context = context;
4695 delete_file_handler (linux_nat_event_pipe[0]);
4696 linux_async_pipe (0);
4701 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4705 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4709 if (debug_linux_nat)
4710 fprintf_unfiltered (gdb_stdlog,
4711 "LNSL: running -> suspending %s\n",
4712 target_pid_to_str (lwp->ptid));
4715 if (lwp->last_resume_kind == resume_stop)
4717 if (debug_linux_nat)
4718 fprintf_unfiltered (gdb_stdlog,
4719 "linux-nat: already stopping LWP %ld at "
4721 ptid_get_lwp (lwp->ptid));
4725 stop_callback (lwp, NULL);
4726 lwp->last_resume_kind = resume_stop;
4730 /* Already known to be stopped; do nothing. */
4732 if (debug_linux_nat)
4734 if (find_thread_ptid (lwp->ptid)->stop_requested)
4735 fprintf_unfiltered (gdb_stdlog,
4736 "LNSL: already stopped/stop_requested %s\n",
4737 target_pid_to_str (lwp->ptid));
4739 fprintf_unfiltered (gdb_stdlog,
4740 "LNSL: already stopped/no "
4741 "stop_requested yet %s\n",
4742 target_pid_to_str (lwp->ptid));
4749 linux_nat_stop (ptid_t ptid)
4752 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4754 linux_ops->to_stop (ptid);
4758 linux_nat_close (void)
4760 /* Unregister from the event loop. */
4761 if (linux_nat_is_async_p ())
4762 linux_nat_async (NULL, 0);
4764 if (linux_ops->to_close)
4765 linux_ops->to_close ();
4768 /* When requests are passed down from the linux-nat layer to the
4769 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4770 used. The address space pointer is stored in the inferior object,
4771 but the common code that is passed such ptid can't tell whether
4772 lwpid is a "main" process id or not (it assumes so). We reverse
4773 look up the "main" process id from the lwp here. */
4775 static struct address_space *
4776 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4778 struct lwp_info *lwp;
4779 struct inferior *inf;
4782 pid = ptid_get_lwp (ptid);
4783 if (ptid_get_lwp (ptid) == 0)
4785 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4787 lwp = find_lwp_pid (ptid);
4788 pid = ptid_get_pid (lwp->ptid);
4792 /* A (pid,lwpid,0) ptid. */
4793 pid = ptid_get_pid (ptid);
4796 inf = find_inferior_pid (pid);
4797 gdb_assert (inf != NULL);
4801 /* Return the cached value of the processor core for thread PTID. */
4804 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4806 struct lwp_info *info = find_lwp_pid (ptid);
4814 linux_nat_add_target (struct target_ops *t)
4816 /* Save the provided single-threaded target. We save this in a separate
4817 variable because another target we've inherited from (e.g. inf-ptrace)
4818 may have saved a pointer to T; we want to use it for the final
4819 process stratum target. */
4820 linux_ops_saved = *t;
4821 linux_ops = &linux_ops_saved;
4823 /* Override some methods for multithreading. */
4824 t->to_create_inferior = linux_nat_create_inferior;
4825 t->to_attach = linux_nat_attach;
4826 t->to_detach = linux_nat_detach;
4827 t->to_resume = linux_nat_resume;
4828 t->to_wait = linux_nat_wait;
4829 t->to_pass_signals = linux_nat_pass_signals;
4830 t->to_xfer_partial = linux_nat_xfer_partial;
4831 t->to_kill = linux_nat_kill;
4832 t->to_mourn_inferior = linux_nat_mourn_inferior;
4833 t->to_thread_alive = linux_nat_thread_alive;
4834 t->to_pid_to_str = linux_nat_pid_to_str;
4835 t->to_thread_name = linux_nat_thread_name;
4836 t->to_has_thread_control = tc_schedlock;
4837 t->to_thread_address_space = linux_nat_thread_address_space;
4838 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4839 t->to_stopped_data_address = linux_nat_stopped_data_address;
4841 t->to_can_async_p = linux_nat_can_async_p;
4842 t->to_is_async_p = linux_nat_is_async_p;
4843 t->to_supports_non_stop = linux_nat_supports_non_stop;
4844 t->to_async = linux_nat_async;
4845 t->to_terminal_inferior = linux_nat_terminal_inferior;
4846 t->to_terminal_ours = linux_nat_terminal_ours;
4847 t->to_close = linux_nat_close;
4849 /* Methods for non-stop support. */
4850 t->to_stop = linux_nat_stop;
4852 t->to_supports_multi_process = linux_nat_supports_multi_process;
4854 t->to_supports_disable_randomization
4855 = linux_nat_supports_disable_randomization;
4857 t->to_core_of_thread = linux_nat_core_of_thread;
4859 /* We don't change the stratum; this target will sit at
4860 process_stratum and thread_db will set at thread_stratum. This
4861 is a little strange, since this is a multi-threaded-capable
4862 target, but we want to be on the stack below thread_db, and we
4863 also want to be used for single-threaded processes. */
4868 /* Register a method to call whenever a new thread is attached. */
4870 linux_nat_set_new_thread (struct target_ops *t,
4871 void (*new_thread) (struct lwp_info *))
4873 /* Save the pointer. We only support a single registered instance
4874 of the GNU/Linux native target, so we do not need to map this to
4876 linux_nat_new_thread = new_thread;
4879 /* See declaration in linux-nat.h. */
4882 linux_nat_set_new_fork (struct target_ops *t,
4883 linux_nat_new_fork_ftype *new_fork)
4885 /* Save the pointer. */
4886 linux_nat_new_fork = new_fork;
4889 /* See declaration in linux-nat.h. */
4892 linux_nat_set_forget_process (struct target_ops *t,
4893 linux_nat_forget_process_ftype *fn)
4895 /* Save the pointer. */
4896 linux_nat_forget_process_hook = fn;
4899 /* See declaration in linux-nat.h. */
4902 linux_nat_forget_process (pid_t pid)
4904 if (linux_nat_forget_process_hook != NULL)
4905 linux_nat_forget_process_hook (pid);
4908 /* Register a method that converts a siginfo object between the layout
4909 that ptrace returns, and the layout in the architecture of the
4912 linux_nat_set_siginfo_fixup (struct target_ops *t,
4913 int (*siginfo_fixup) (siginfo_t *,
4917 /* Save the pointer. */
4918 linux_nat_siginfo_fixup = siginfo_fixup;
4921 /* Register a method to call prior to resuming a thread. */
4924 linux_nat_set_prepare_to_resume (struct target_ops *t,
4925 void (*prepare_to_resume) (struct lwp_info *))
4927 /* Save the pointer. */
4928 linux_nat_prepare_to_resume = prepare_to_resume;
4931 /* See linux-nat.h. */
4934 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4938 pid = ptid_get_lwp (ptid);
4940 pid = ptid_get_pid (ptid);
4943 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4946 memset (siginfo, 0, sizeof (*siginfo));
4952 /* Provide a prototype to silence -Wmissing-prototypes. */
4953 extern initialize_file_ftype _initialize_linux_nat;
4956 _initialize_linux_nat (void)
4958 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4959 &debug_linux_nat, _("\
4960 Set debugging of GNU/Linux lwp module."), _("\
4961 Show debugging of GNU/Linux lwp module."), _("\
4962 Enables printf debugging output."),
4964 show_debug_linux_nat,
4965 &setdebuglist, &showdebuglist);
4967 /* Save this mask as the default. */
4968 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4970 /* Install a SIGCHLD handler. */
4971 sigchld_action.sa_handler = sigchld_handler;
4972 sigemptyset (&sigchld_action.sa_mask);
4973 sigchld_action.sa_flags = SA_RESTART;
4975 /* Make it the default. */
4976 sigaction (SIGCHLD, &sigchld_action, NULL);
4978 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4979 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
4980 sigdelset (&suspend_mask, SIGCHLD);
4982 sigemptyset (&blocked_mask);
4986 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4987 the GNU/Linux Threads library and therefore doesn't really belong
4990 /* Read variable NAME in the target and return its value if found.
4991 Otherwise return zero. It is assumed that the type of the variable
4995 get_signo (const char *name)
4997 struct minimal_symbol *ms;
5000 ms = lookup_minimal_symbol (name, NULL, NULL);
5004 if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
5005 sizeof (signo)) != 0)
5011 /* Return the set of signals used by the threads library in *SET. */
5014 lin_thread_get_thread_signals (sigset_t *set)
5016 struct sigaction action;
5017 int restart, cancel;
5019 sigemptyset (&blocked_mask);
5022 restart = get_signo ("__pthread_sig_restart");
5023 cancel = get_signo ("__pthread_sig_cancel");
5025 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5026 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5027 not provide any way for the debugger to query the signal numbers -
5028 fortunately they don't change! */
5031 restart = __SIGRTMIN;
5034 cancel = __SIGRTMIN + 1;
5036 sigaddset (set, restart);
5037 sigaddset (set, cancel);
5039 /* The GNU/Linux Threads library makes terminating threads send a
5040 special "cancel" signal instead of SIGCHLD. Make sure we catch
5041 those (to prevent them from terminating GDB itself, which is
5042 likely to be their default action) and treat them the same way as
5045 action.sa_handler = sigchld_handler;
5046 sigemptyset (&action.sa_mask);
5047 action.sa_flags = SA_RESTART;
5048 sigaction (cancel, &action, NULL);
5050 /* We block the "cancel" signal throughout this code ... */
5051 sigaddset (&blocked_mask, cancel);
5052 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
5054 /* ... except during a sigsuspend. */
5055 sigdelset (&suspend_mask, cancel);