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"
25 #include "gdb_string.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 "gdb_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>
57 #include "gdb_dirent.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 LONGEST (*super_xfer_partial) (struct target_ops *,
205 const char *, gdb_byte *,
209 static unsigned int debug_linux_nat;
211 show_debug_linux_nat (struct ui_file *file, int from_tty,
212 struct cmd_list_element *c, const char *value)
214 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
218 struct simple_pid_list
222 struct simple_pid_list *next;
224 struct simple_pid_list *stopped_pids;
226 /* Async mode support. */
228 /* The read/write ends of the pipe registered as waitable file in the
230 static int linux_nat_event_pipe[2] = { -1, -1 };
232 /* Flush the event pipe. */
235 async_file_flush (void)
242 ret = read (linux_nat_event_pipe[0], &buf, 1);
244 while (ret >= 0 || (ret == -1 && errno == EINTR));
247 /* Put something (anything, doesn't matter what, or how much) in event
248 pipe, so that the select/poll in the event-loop realizes we have
249 something to process. */
252 async_file_mark (void)
256 /* It doesn't really matter what the pipe contains, as long we end
257 up with something in it. Might as well flush the previous
263 ret = write (linux_nat_event_pipe[1], "+", 1);
265 while (ret == -1 && errno == EINTR);
267 /* Ignore EAGAIN. If the pipe is full, the event loop will already
268 be awakened anyway. */
271 static void linux_nat_async (void (*callback)
272 (enum inferior_event_type event_type,
275 static int kill_lwp (int lwpid, int signo);
277 static int stop_callback (struct lwp_info *lp, void *data);
279 static void block_child_signals (sigset_t *prev_mask);
280 static void restore_child_signals_mask (sigset_t *prev_mask);
283 static struct lwp_info *add_lwp (ptid_t ptid);
284 static void purge_lwp_list (int pid);
285 static void delete_lwp (ptid_t ptid);
286 static struct lwp_info *find_lwp_pid (ptid_t ptid);
289 /* Trivial list manipulation functions to keep track of a list of
290 new stopped processes. */
292 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
294 struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
297 new_pid->status = status;
298 new_pid->next = *listp;
303 in_pid_list_p (struct simple_pid_list *list, int pid)
305 struct simple_pid_list *p;
307 for (p = list; p != NULL; p = p->next)
314 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
316 struct simple_pid_list **p;
318 for (p = listp; *p != NULL; p = &(*p)->next)
319 if ((*p)->pid == pid)
321 struct simple_pid_list *next = (*p)->next;
323 *statusp = (*p)->status;
331 /* Initialize ptrace warnings and check for supported ptrace
332 features given PID. */
335 linux_init_ptrace (pid_t pid)
337 linux_enable_event_reporting (pid);
338 linux_ptrace_init_warnings ();
342 linux_child_post_attach (int pid)
344 linux_init_ptrace (pid);
348 linux_child_post_startup_inferior (ptid_t ptid)
350 linux_init_ptrace (ptid_get_pid (ptid));
353 /* Return the number of known LWPs in the tgid given by PID. */
361 for (lp = lwp_list; lp; lp = lp->next)
362 if (ptid_get_pid (lp->ptid) == pid)
368 /* Call delete_lwp with prototype compatible for make_cleanup. */
371 delete_lwp_cleanup (void *lp_voidp)
373 struct lwp_info *lp = lp_voidp;
375 delete_lwp (lp->ptid);
379 linux_child_follow_fork (struct target_ops *ops, int follow_child,
383 int parent_pid, child_pid;
385 has_vforked = (inferior_thread ()->pending_follow.kind
386 == TARGET_WAITKIND_VFORKED);
387 parent_pid = ptid_get_lwp (inferior_ptid);
389 parent_pid = ptid_get_pid (inferior_ptid);
391 = ptid_get_pid (inferior_thread ()->pending_follow.value.related_pid);
394 && !non_stop /* Non-stop always resumes both branches. */
395 && (!target_is_async_p () || sync_execution)
396 && !(follow_child || detach_fork || sched_multi))
398 /* The parent stays blocked inside the vfork syscall until the
399 child execs or exits. If we don't let the child run, then
400 the parent stays blocked. If we're telling the parent to run
401 in the foreground, the user will not be able to ctrl-c to get
402 back the terminal, effectively hanging the debug session. */
403 fprintf_filtered (gdb_stderr, _("\
404 Can not resume the parent process over vfork in the foreground while\n\
405 holding the child stopped. Try \"set detach-on-fork\" or \
406 \"set schedule-multiple\".\n"));
407 /* FIXME output string > 80 columns. */
413 struct lwp_info *child_lp = NULL;
415 /* We're already attached to the parent, by default. */
417 /* Detach new forked process? */
420 struct cleanup *old_chain;
422 /* Before detaching from the child, remove all breakpoints
423 from it. If we forked, then this has already been taken
424 care of by infrun.c. If we vforked however, any
425 breakpoint inserted in the parent is visible in the
426 child, even those added while stopped in a vfork
427 catchpoint. This will remove the breakpoints from the
428 parent also, but they'll be reinserted below. */
431 /* keep breakpoints list in sync. */
432 remove_breakpoints_pid (ptid_get_pid (inferior_ptid));
435 if (info_verbose || debug_linux_nat)
437 target_terminal_ours ();
438 fprintf_filtered (gdb_stdlog,
439 "Detaching after fork from "
440 "child process %d.\n",
444 old_chain = save_inferior_ptid ();
445 inferior_ptid = ptid_build (child_pid, child_pid, 0);
447 child_lp = add_lwp (inferior_ptid);
448 child_lp->stopped = 1;
449 child_lp->last_resume_kind = resume_stop;
450 make_cleanup (delete_lwp_cleanup, child_lp);
452 if (linux_nat_prepare_to_resume != NULL)
453 linux_nat_prepare_to_resume (child_lp);
454 ptrace (PTRACE_DETACH, child_pid, 0, 0);
456 do_cleanups (old_chain);
460 struct inferior *parent_inf, *child_inf;
461 struct cleanup *old_chain;
463 /* Add process to GDB's tables. */
464 child_inf = add_inferior (child_pid);
466 parent_inf = current_inferior ();
467 child_inf->attach_flag = parent_inf->attach_flag;
468 copy_terminal_info (child_inf, parent_inf);
469 child_inf->gdbarch = parent_inf->gdbarch;
470 copy_inferior_target_desc_info (child_inf, parent_inf);
472 old_chain = save_inferior_ptid ();
473 save_current_program_space ();
475 inferior_ptid = ptid_build (child_pid, child_pid, 0);
476 add_thread (inferior_ptid);
477 child_lp = add_lwp (inferior_ptid);
478 child_lp->stopped = 1;
479 child_lp->last_resume_kind = resume_stop;
480 child_inf->symfile_flags = SYMFILE_NO_READ;
482 /* If this is a vfork child, then the address-space is
483 shared with the parent. */
486 child_inf->pspace = parent_inf->pspace;
487 child_inf->aspace = parent_inf->aspace;
489 /* The parent will be frozen until the child is done
490 with the shared region. Keep track of the
492 child_inf->vfork_parent = parent_inf;
493 child_inf->pending_detach = 0;
494 parent_inf->vfork_child = child_inf;
495 parent_inf->pending_detach = 0;
499 child_inf->aspace = new_address_space ();
500 child_inf->pspace = add_program_space (child_inf->aspace);
501 child_inf->removable = 1;
502 set_current_program_space (child_inf->pspace);
503 clone_program_space (child_inf->pspace, parent_inf->pspace);
505 /* Let the shared library layer (solib-svr4) learn about
506 this new process, relocate the cloned exec, pull in
507 shared libraries, and install the solib event
508 breakpoint. If a "cloned-VM" event was propagated
509 better throughout the core, this wouldn't be
511 solib_create_inferior_hook (0);
514 /* Let the thread_db layer learn about this new process. */
515 check_for_thread_db ();
517 do_cleanups (old_chain);
522 struct lwp_info *parent_lp;
523 struct inferior *parent_inf;
525 parent_inf = current_inferior ();
527 /* If we detached from the child, then we have to be careful
528 to not insert breakpoints in the parent until the child
529 is done with the shared memory region. However, if we're
530 staying attached to the child, then we can and should
531 insert breakpoints, so that we can debug it. A
532 subsequent child exec or exit is enough to know when does
533 the child stops using the parent's address space. */
534 parent_inf->waiting_for_vfork_done = detach_fork;
535 parent_inf->pspace->breakpoints_not_allowed = detach_fork;
537 parent_lp = find_lwp_pid (pid_to_ptid (parent_pid));
538 gdb_assert (linux_supports_tracefork () >= 0);
540 if (linux_supports_tracevforkdone ())
543 fprintf_unfiltered (gdb_stdlog,
544 "LCFF: waiting for VFORK_DONE on %d\n",
546 parent_lp->stopped = 1;
548 /* We'll handle the VFORK_DONE event like any other
549 event, in target_wait. */
553 /* We can't insert breakpoints until the child has
554 finished with the shared memory region. We need to
555 wait until that happens. Ideal would be to just
557 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
558 - waitpid (parent_pid, &status, __WALL);
559 However, most architectures can't handle a syscall
560 being traced on the way out if it wasn't traced on
563 We might also think to loop, continuing the child
564 until it exits or gets a SIGTRAP. One problem is
565 that the child might call ptrace with PTRACE_TRACEME.
567 There's no simple and reliable way to figure out when
568 the vforked child will be done with its copy of the
569 shared memory. We could step it out of the syscall,
570 two instructions, let it go, and then single-step the
571 parent once. When we have hardware single-step, this
572 would work; with software single-step it could still
573 be made to work but we'd have to be able to insert
574 single-step breakpoints in the child, and we'd have
575 to insert -just- the single-step breakpoint in the
576 parent. Very awkward.
578 In the end, the best we can do is to make sure it
579 runs for a little while. Hopefully it will be out of
580 range of any breakpoints we reinsert. Usually this
581 is only the single-step breakpoint at vfork's return
585 fprintf_unfiltered (gdb_stdlog,
586 "LCFF: no VFORK_DONE "
587 "support, sleeping a bit\n");
591 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
592 and leave it pending. The next linux_nat_resume call
593 will notice a pending event, and bypasses actually
594 resuming the inferior. */
595 parent_lp->status = 0;
596 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
597 parent_lp->stopped = 1;
599 /* If we're in async mode, need to tell the event loop
600 there's something here to process. */
601 if (target_can_async_p ())
608 struct inferior *parent_inf, *child_inf;
609 struct lwp_info *child_lp;
610 struct program_space *parent_pspace;
612 if (info_verbose || debug_linux_nat)
614 target_terminal_ours ();
616 fprintf_filtered (gdb_stdlog,
617 _("Attaching after process %d "
618 "vfork to child process %d.\n"),
619 parent_pid, child_pid);
621 fprintf_filtered (gdb_stdlog,
622 _("Attaching after process %d "
623 "fork to child process %d.\n"),
624 parent_pid, child_pid);
627 /* Add the new inferior first, so that the target_detach below
628 doesn't unpush the target. */
630 child_inf = add_inferior (child_pid);
632 parent_inf = current_inferior ();
633 child_inf->attach_flag = parent_inf->attach_flag;
634 copy_terminal_info (child_inf, parent_inf);
635 child_inf->gdbarch = parent_inf->gdbarch;
636 copy_inferior_target_desc_info (child_inf, parent_inf);
638 parent_pspace = parent_inf->pspace;
640 /* If we're vforking, we want to hold on to the parent until the
641 child exits or execs. At child exec or exit time we can
642 remove the old breakpoints from the parent and detach or
643 resume debugging it. Otherwise, detach the parent now; we'll
644 want to reuse it's program/address spaces, but we can't set
645 them to the child before removing breakpoints from the
646 parent, otherwise, the breakpoints module could decide to
647 remove breakpoints from the wrong process (since they'd be
648 assigned to the same address space). */
652 gdb_assert (child_inf->vfork_parent == NULL);
653 gdb_assert (parent_inf->vfork_child == NULL);
654 child_inf->vfork_parent = parent_inf;
655 child_inf->pending_detach = 0;
656 parent_inf->vfork_child = child_inf;
657 parent_inf->pending_detach = detach_fork;
658 parent_inf->waiting_for_vfork_done = 0;
660 else if (detach_fork)
661 target_detach (NULL, 0);
663 /* Note that the detach above makes PARENT_INF dangling. */
665 /* Add the child thread to the appropriate lists, and switch to
666 this new thread, before cloning the program space, and
667 informing the solib layer about this new process. */
669 inferior_ptid = ptid_build (child_pid, child_pid, 0);
670 add_thread (inferior_ptid);
671 child_lp = add_lwp (inferior_ptid);
672 child_lp->stopped = 1;
673 child_lp->last_resume_kind = resume_stop;
675 /* If this is a vfork child, then the address-space is shared
676 with the parent. If we detached from the parent, then we can
677 reuse the parent's program/address spaces. */
678 if (has_vforked || detach_fork)
680 child_inf->pspace = parent_pspace;
681 child_inf->aspace = child_inf->pspace->aspace;
685 child_inf->aspace = new_address_space ();
686 child_inf->pspace = add_program_space (child_inf->aspace);
687 child_inf->removable = 1;
688 child_inf->symfile_flags = SYMFILE_NO_READ;
689 set_current_program_space (child_inf->pspace);
690 clone_program_space (child_inf->pspace, parent_pspace);
692 /* Let the shared library layer (solib-svr4) learn about
693 this new process, relocate the cloned exec, pull in
694 shared libraries, and install the solib event breakpoint.
695 If a "cloned-VM" event was propagated better throughout
696 the core, this wouldn't be required. */
697 solib_create_inferior_hook (0);
700 /* Let the thread_db layer learn about this new process. */
701 check_for_thread_db ();
709 linux_child_insert_fork_catchpoint (int pid)
711 return !linux_supports_tracefork ();
715 linux_child_remove_fork_catchpoint (int pid)
721 linux_child_insert_vfork_catchpoint (int pid)
723 return !linux_supports_tracefork ();
727 linux_child_remove_vfork_catchpoint (int pid)
733 linux_child_insert_exec_catchpoint (int pid)
735 return !linux_supports_tracefork ();
739 linux_child_remove_exec_catchpoint (int pid)
745 linux_child_set_syscall_catchpoint (int pid, int needed, int any_count,
746 int table_size, int *table)
748 if (!linux_supports_tracesysgood ())
751 /* On GNU/Linux, we ignore the arguments. It means that we only
752 enable the syscall catchpoints, but do not disable them.
754 Also, we do not use the `table' information because we do not
755 filter system calls here. We let GDB do the logic for us. */
759 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
760 are processes sharing the same VM space. A multi-threaded process
761 is basically a group of such processes. However, such a grouping
762 is almost entirely a user-space issue; the kernel doesn't enforce
763 such a grouping at all (this might change in the future). In
764 general, we'll rely on the threads library (i.e. the GNU/Linux
765 Threads library) to provide such a grouping.
767 It is perfectly well possible to write a multi-threaded application
768 without the assistance of a threads library, by using the clone
769 system call directly. This module should be able to give some
770 rudimentary support for debugging such applications if developers
771 specify the CLONE_PTRACE flag in the clone system call, and are
772 using the Linux kernel 2.4 or above.
774 Note that there are some peculiarities in GNU/Linux that affect
777 - In general one should specify the __WCLONE flag to waitpid in
778 order to make it report events for any of the cloned processes
779 (and leave it out for the initial process). However, if a cloned
780 process has exited the exit status is only reported if the
781 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
782 we cannot use it since GDB must work on older systems too.
784 - When a traced, cloned process exits and is waited for by the
785 debugger, the kernel reassigns it to the original parent and
786 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
787 library doesn't notice this, which leads to the "zombie problem":
788 When debugged a multi-threaded process that spawns a lot of
789 threads will run out of processes, even if the threads exit,
790 because the "zombies" stay around. */
792 /* List of known LWPs. */
793 struct lwp_info *lwp_list;
796 /* Original signal mask. */
797 static sigset_t normal_mask;
799 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
800 _initialize_linux_nat. */
801 static sigset_t suspend_mask;
803 /* Signals to block to make that sigsuspend work. */
804 static sigset_t blocked_mask;
806 /* SIGCHLD action. */
807 struct sigaction sigchld_action;
809 /* Block child signals (SIGCHLD and linux threads signals), and store
810 the previous mask in PREV_MASK. */
813 block_child_signals (sigset_t *prev_mask)
815 /* Make sure SIGCHLD is blocked. */
816 if (!sigismember (&blocked_mask, SIGCHLD))
817 sigaddset (&blocked_mask, SIGCHLD);
819 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
822 /* Restore child signals mask, previously returned by
823 block_child_signals. */
826 restore_child_signals_mask (sigset_t *prev_mask)
828 sigprocmask (SIG_SETMASK, prev_mask, NULL);
831 /* Mask of signals to pass directly to the inferior. */
832 static sigset_t pass_mask;
834 /* Update signals to pass to the inferior. */
836 linux_nat_pass_signals (int numsigs, unsigned char *pass_signals)
840 sigemptyset (&pass_mask);
842 for (signo = 1; signo < NSIG; signo++)
844 int target_signo = gdb_signal_from_host (signo);
845 if (target_signo < numsigs && pass_signals[target_signo])
846 sigaddset (&pass_mask, signo);
852 /* Prototypes for local functions. */
853 static int stop_wait_callback (struct lwp_info *lp, void *data);
854 static int linux_thread_alive (ptid_t ptid);
855 static char *linux_child_pid_to_exec_file (int pid);
858 /* Convert wait status STATUS to a string. Used for printing debug
862 status_to_str (int status)
866 if (WIFSTOPPED (status))
868 if (WSTOPSIG (status) == SYSCALL_SIGTRAP)
869 snprintf (buf, sizeof (buf), "%s (stopped at syscall)",
870 strsignal (SIGTRAP));
872 snprintf (buf, sizeof (buf), "%s (stopped)",
873 strsignal (WSTOPSIG (status)));
875 else if (WIFSIGNALED (status))
876 snprintf (buf, sizeof (buf), "%s (terminated)",
877 strsignal (WTERMSIG (status)));
879 snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status));
884 /* Destroy and free LP. */
887 lwp_free (struct lwp_info *lp)
889 xfree (lp->arch_private);
893 /* Remove all LWPs belong to PID from the lwp list. */
896 purge_lwp_list (int pid)
898 struct lwp_info *lp, *lpprev, *lpnext;
902 for (lp = lwp_list; lp; lp = lpnext)
906 if (ptid_get_pid (lp->ptid) == pid)
911 lpprev->next = lp->next;
920 /* Add the LWP specified by PTID to the list. PTID is the first LWP
921 in the process. Return a pointer to the structure describing the
924 This differs from add_lwp in that we don't let the arch specific
925 bits know about this new thread. Current clients of this callback
926 take the opportunity to install watchpoints in the new thread, and
927 we shouldn't do that for the first thread. If we're spawning a
928 child ("run"), the thread executes the shell wrapper first, and we
929 shouldn't touch it until it execs the program we want to debug.
930 For "attach", it'd be okay to call the callback, but it's not
931 necessary, because watchpoints can't yet have been inserted into
934 static struct lwp_info *
935 add_initial_lwp (ptid_t ptid)
939 gdb_assert (ptid_lwp_p (ptid));
941 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
943 memset (lp, 0, sizeof (struct lwp_info));
945 lp->last_resume_kind = resume_continue;
946 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
957 /* Add the LWP specified by PID to the list. Return a pointer to the
958 structure describing the new LWP. The LWP should already be
961 static struct lwp_info *
962 add_lwp (ptid_t ptid)
966 lp = add_initial_lwp (ptid);
968 /* Let the arch specific bits know about this new thread. Current
969 clients of this callback take the opportunity to install
970 watchpoints in the new thread. We don't do this for the first
971 thread though. See add_initial_lwp. */
972 if (linux_nat_new_thread != NULL)
973 linux_nat_new_thread (lp);
978 /* Remove the LWP specified by PID from the list. */
981 delete_lwp (ptid_t ptid)
983 struct lwp_info *lp, *lpprev;
987 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
988 if (ptid_equal (lp->ptid, ptid))
995 lpprev->next = lp->next;
1002 /* Return a pointer to the structure describing the LWP corresponding
1003 to PID. If no corresponding LWP could be found, return NULL. */
1005 static struct lwp_info *
1006 find_lwp_pid (ptid_t ptid)
1008 struct lwp_info *lp;
1011 if (ptid_lwp_p (ptid))
1012 lwp = ptid_get_lwp (ptid);
1014 lwp = ptid_get_pid (ptid);
1016 for (lp = lwp_list; lp; lp = lp->next)
1017 if (lwp == ptid_get_lwp (lp->ptid))
1023 /* Call CALLBACK with its second argument set to DATA for every LWP in
1024 the list. If CALLBACK returns 1 for a particular LWP, return a
1025 pointer to the structure describing that LWP immediately.
1026 Otherwise return NULL. */
1029 iterate_over_lwps (ptid_t filter,
1030 int (*callback) (struct lwp_info *, void *),
1033 struct lwp_info *lp, *lpnext;
1035 for (lp = lwp_list; lp; lp = lpnext)
1039 if (ptid_match (lp->ptid, filter))
1041 if ((*callback) (lp, data))
1049 /* Update our internal state when changing from one checkpoint to
1050 another indicated by NEW_PTID. We can only switch single-threaded
1051 applications, so we only create one new LWP, and the previous list
1055 linux_nat_switch_fork (ptid_t new_ptid)
1057 struct lwp_info *lp;
1059 purge_lwp_list (ptid_get_pid (inferior_ptid));
1061 lp = add_lwp (new_ptid);
1064 /* This changes the thread's ptid while preserving the gdb thread
1065 num. Also changes the inferior pid, while preserving the
1067 thread_change_ptid (inferior_ptid, new_ptid);
1069 /* We've just told GDB core that the thread changed target id, but,
1070 in fact, it really is a different thread, with different register
1072 registers_changed ();
1075 /* Handle the exit of a single thread LP. */
1078 exit_lwp (struct lwp_info *lp)
1080 struct thread_info *th = find_thread_ptid (lp->ptid);
1084 if (print_thread_events)
1085 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
1087 delete_thread (lp->ptid);
1090 delete_lwp (lp->ptid);
1093 /* Wait for the LWP specified by LP, which we have just attached to.
1094 Returns a wait status for that LWP, to cache. */
1097 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
1100 pid_t new_pid, pid = ptid_get_lwp (ptid);
1103 if (linux_proc_pid_is_stopped (pid))
1105 if (debug_linux_nat)
1106 fprintf_unfiltered (gdb_stdlog,
1107 "LNPAW: Attaching to a stopped process\n");
1109 /* The process is definitely stopped. It is in a job control
1110 stop, unless the kernel predates the TASK_STOPPED /
1111 TASK_TRACED distinction, in which case it might be in a
1112 ptrace stop. Make sure it is in a ptrace stop; from there we
1113 can kill it, signal it, et cetera.
1115 First make sure there is a pending SIGSTOP. Since we are
1116 already attached, the process can not transition from stopped
1117 to running without a PTRACE_CONT; so we know this signal will
1118 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1119 probably already in the queue (unless this kernel is old
1120 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1121 is not an RT signal, it can only be queued once. */
1122 kill_lwp (pid, SIGSTOP);
1124 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1125 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1126 ptrace (PTRACE_CONT, pid, 0, 0);
1129 /* Make sure the initial process is stopped. The user-level threads
1130 layer might want to poke around in the inferior, and that won't
1131 work if things haven't stabilized yet. */
1132 new_pid = my_waitpid (pid, &status, 0);
1133 if (new_pid == -1 && errno == ECHILD)
1136 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
1138 /* Try again with __WCLONE to check cloned processes. */
1139 new_pid = my_waitpid (pid, &status, __WCLONE);
1143 gdb_assert (pid == new_pid);
1145 if (!WIFSTOPPED (status))
1147 /* The pid we tried to attach has apparently just exited. */
1148 if (debug_linux_nat)
1149 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1150 pid, status_to_str (status));
1154 if (WSTOPSIG (status) != SIGSTOP)
1157 if (debug_linux_nat)
1158 fprintf_unfiltered (gdb_stdlog,
1159 "LNPAW: Received %s after attaching\n",
1160 status_to_str (status));
1166 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1167 the new LWP could not be attached, or 1 if we're already auto
1168 attached to this thread, but haven't processed the
1169 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1170 its existance, without considering it an error. */
1173 lin_lwp_attach_lwp (ptid_t ptid)
1175 struct lwp_info *lp;
1178 gdb_assert (ptid_lwp_p (ptid));
1180 lp = find_lwp_pid (ptid);
1181 lwpid = ptid_get_lwp (ptid);
1183 /* We assume that we're already attached to any LWP that has an id
1184 equal to the overall process id, and to any LWP that is already
1185 in our list of LWPs. If we're not seeing exit events from threads
1186 and we've had PID wraparound since we last tried to stop all threads,
1187 this assumption might be wrong; fortunately, this is very unlikely
1189 if (lwpid != ptid_get_pid (ptid) && lp == NULL)
1191 int status, cloned = 0, signalled = 0;
1193 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1195 if (linux_supports_tracefork ())
1197 /* If we haven't stopped all threads when we get here,
1198 we may have seen a thread listed in thread_db's list,
1199 but not processed the PTRACE_EVENT_CLONE yet. If
1200 that's the case, ignore this new thread, and let
1201 normal event handling discover it later. */
1202 if (in_pid_list_p (stopped_pids, lwpid))
1204 /* We've already seen this thread stop, but we
1205 haven't seen the PTRACE_EVENT_CLONE extended
1214 /* See if we've got a stop for this new child
1215 pending. If so, we're already attached. */
1216 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1217 if (new_pid == -1 && errno == ECHILD)
1218 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1221 if (WIFSTOPPED (status))
1222 add_to_pid_list (&stopped_pids, lwpid, status);
1228 /* If we fail to attach to the thread, issue a warning,
1229 but continue. One way this can happen is if thread
1230 creation is interrupted; as of Linux kernel 2.6.19, a
1231 bug may place threads in the thread list and then fail
1233 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1234 safe_strerror (errno));
1238 if (debug_linux_nat)
1239 fprintf_unfiltered (gdb_stdlog,
1240 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1241 target_pid_to_str (ptid));
1243 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1244 if (!WIFSTOPPED (status))
1247 lp = add_lwp (ptid);
1249 lp->cloned = cloned;
1250 lp->signalled = signalled;
1251 if (WSTOPSIG (status) != SIGSTOP)
1254 lp->status = status;
1257 target_post_attach (ptid_get_lwp (lp->ptid));
1259 if (debug_linux_nat)
1261 fprintf_unfiltered (gdb_stdlog,
1262 "LLAL: waitpid %s received %s\n",
1263 target_pid_to_str (ptid),
1264 status_to_str (status));
1269 /* We assume that the LWP representing the original process is
1270 already stopped. Mark it as stopped in the data structure
1271 that the GNU/linux ptrace layer uses to keep track of
1272 threads. Note that this won't have already been done since
1273 the main thread will have, we assume, been stopped by an
1274 attach from a different layer. */
1276 lp = add_lwp (ptid);
1280 lp->last_resume_kind = resume_stop;
1285 linux_nat_create_inferior (struct target_ops *ops,
1286 char *exec_file, char *allargs, char **env,
1289 #ifdef HAVE_PERSONALITY
1290 int personality_orig = 0, personality_set = 0;
1291 #endif /* HAVE_PERSONALITY */
1293 /* The fork_child mechanism is synchronous and calls target_wait, so
1294 we have to mask the async mode. */
1296 #ifdef HAVE_PERSONALITY
1297 if (disable_randomization)
1300 personality_orig = personality (0xffffffff);
1301 if (errno == 0 && !(personality_orig & ADDR_NO_RANDOMIZE))
1303 personality_set = 1;
1304 personality (personality_orig | ADDR_NO_RANDOMIZE);
1306 if (errno != 0 || (personality_set
1307 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE)))
1308 warning (_("Error disabling address space randomization: %s"),
1309 safe_strerror (errno));
1311 #endif /* HAVE_PERSONALITY */
1313 /* Make sure we report all signals during startup. */
1314 linux_nat_pass_signals (0, NULL);
1316 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1318 #ifdef HAVE_PERSONALITY
1319 if (personality_set)
1322 personality (personality_orig);
1324 warning (_("Error restoring address space randomization: %s"),
1325 safe_strerror (errno));
1327 #endif /* HAVE_PERSONALITY */
1331 linux_nat_attach (struct target_ops *ops, char *args, int from_tty)
1333 struct lwp_info *lp;
1336 volatile struct gdb_exception ex;
1338 /* Make sure we report all signals during attach. */
1339 linux_nat_pass_signals (0, NULL);
1341 TRY_CATCH (ex, RETURN_MASK_ERROR)
1343 linux_ops->to_attach (ops, args, from_tty);
1347 pid_t pid = parse_pid_to_attach (args);
1348 struct buffer buffer;
1349 char *message, *buffer_s;
1351 message = xstrdup (ex.message);
1352 make_cleanup (xfree, message);
1354 buffer_init (&buffer);
1355 linux_ptrace_attach_warnings (pid, &buffer);
1357 buffer_grow_str0 (&buffer, "");
1358 buffer_s = buffer_finish (&buffer);
1359 make_cleanup (xfree, buffer_s);
1361 throw_error (ex.error, "%s%s", buffer_s, message);
1364 /* The ptrace base target adds the main thread with (pid,0,0)
1365 format. Decorate it with lwp info. */
1366 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1367 ptid_get_pid (inferior_ptid),
1369 thread_change_ptid (inferior_ptid, ptid);
1371 /* Add the initial process as the first LWP to the list. */
1372 lp = add_initial_lwp (ptid);
1374 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1376 if (!WIFSTOPPED (status))
1378 if (WIFEXITED (status))
1380 int exit_code = WEXITSTATUS (status);
1382 target_terminal_ours ();
1383 target_mourn_inferior ();
1385 error (_("Unable to attach: program exited normally."));
1387 error (_("Unable to attach: program exited with code %d."),
1390 else if (WIFSIGNALED (status))
1392 enum gdb_signal signo;
1394 target_terminal_ours ();
1395 target_mourn_inferior ();
1397 signo = gdb_signal_from_host (WTERMSIG (status));
1398 error (_("Unable to attach: program terminated with signal "
1400 gdb_signal_to_name (signo),
1401 gdb_signal_to_string (signo));
1404 internal_error (__FILE__, __LINE__,
1405 _("unexpected status %d for PID %ld"),
1406 status, (long) ptid_get_lwp (ptid));
1411 /* Save the wait status to report later. */
1413 if (debug_linux_nat)
1414 fprintf_unfiltered (gdb_stdlog,
1415 "LNA: waitpid %ld, saving status %s\n",
1416 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1418 lp->status = status;
1420 if (target_can_async_p ())
1421 target_async (inferior_event_handler, 0);
1424 /* Get pending status of LP. */
1426 get_pending_status (struct lwp_info *lp, int *status)
1428 enum gdb_signal signo = GDB_SIGNAL_0;
1430 /* If we paused threads momentarily, we may have stored pending
1431 events in lp->status or lp->waitstatus (see stop_wait_callback),
1432 and GDB core hasn't seen any signal for those threads.
1433 Otherwise, the last signal reported to the core is found in the
1434 thread object's stop_signal.
1436 There's a corner case that isn't handled here at present. Only
1437 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1438 stop_signal make sense as a real signal to pass to the inferior.
1439 Some catchpoint related events, like
1440 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1441 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1442 those traps are debug API (ptrace in our case) related and
1443 induced; the inferior wouldn't see them if it wasn't being
1444 traced. Hence, we should never pass them to the inferior, even
1445 when set to pass state. Since this corner case isn't handled by
1446 infrun.c when proceeding with a signal, for consistency, neither
1447 do we handle it here (or elsewhere in the file we check for
1448 signal pass state). Normally SIGTRAP isn't set to pass state, so
1449 this is really a corner case. */
1451 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1452 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1453 else if (lp->status)
1454 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1455 else if (non_stop && !is_executing (lp->ptid))
1457 struct thread_info *tp = find_thread_ptid (lp->ptid);
1459 signo = tp->suspend.stop_signal;
1463 struct target_waitstatus last;
1466 get_last_target_status (&last_ptid, &last);
1468 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1470 struct thread_info *tp = find_thread_ptid (lp->ptid);
1472 signo = tp->suspend.stop_signal;
1478 if (signo == GDB_SIGNAL_0)
1480 if (debug_linux_nat)
1481 fprintf_unfiltered (gdb_stdlog,
1482 "GPT: lwp %s has no pending signal\n",
1483 target_pid_to_str (lp->ptid));
1485 else if (!signal_pass_state (signo))
1487 if (debug_linux_nat)
1488 fprintf_unfiltered (gdb_stdlog,
1489 "GPT: lwp %s had signal %s, "
1490 "but it is in no pass state\n",
1491 target_pid_to_str (lp->ptid),
1492 gdb_signal_to_string (signo));
1496 *status = W_STOPCODE (gdb_signal_to_host (signo));
1498 if (debug_linux_nat)
1499 fprintf_unfiltered (gdb_stdlog,
1500 "GPT: lwp %s has pending signal %s\n",
1501 target_pid_to_str (lp->ptid),
1502 gdb_signal_to_string (signo));
1509 detach_callback (struct lwp_info *lp, void *data)
1511 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1513 if (debug_linux_nat && lp->status)
1514 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1515 strsignal (WSTOPSIG (lp->status)),
1516 target_pid_to_str (lp->ptid));
1518 /* If there is a pending SIGSTOP, get rid of it. */
1521 if (debug_linux_nat)
1522 fprintf_unfiltered (gdb_stdlog,
1523 "DC: Sending SIGCONT to %s\n",
1524 target_pid_to_str (lp->ptid));
1526 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1530 /* We don't actually detach from the LWP that has an id equal to the
1531 overall process id just yet. */
1532 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1536 /* Pass on any pending signal for this LWP. */
1537 get_pending_status (lp, &status);
1539 if (linux_nat_prepare_to_resume != NULL)
1540 linux_nat_prepare_to_resume (lp);
1542 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1543 WSTOPSIG (status)) < 0)
1544 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1545 safe_strerror (errno));
1547 if (debug_linux_nat)
1548 fprintf_unfiltered (gdb_stdlog,
1549 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1550 target_pid_to_str (lp->ptid),
1551 strsignal (WSTOPSIG (status)));
1553 delete_lwp (lp->ptid);
1560 linux_nat_detach (struct target_ops *ops, char *args, int from_tty)
1564 struct lwp_info *main_lwp;
1566 pid = ptid_get_pid (inferior_ptid);
1568 /* Don't unregister from the event loop, as there may be other
1569 inferiors running. */
1571 /* Stop all threads before detaching. ptrace requires that the
1572 thread is stopped to sucessfully detach. */
1573 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1574 /* ... and wait until all of them have reported back that
1575 they're no longer running. */
1576 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1578 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1580 /* Only the initial process should be left right now. */
1581 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1583 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1585 /* Pass on any pending signal for the last LWP. */
1586 if ((args == NULL || *args == '\0')
1587 && get_pending_status (main_lwp, &status) != -1
1588 && WIFSTOPPED (status))
1590 /* Put the signal number in ARGS so that inf_ptrace_detach will
1591 pass it along with PTRACE_DETACH. */
1593 sprintf (args, "%d", (int) WSTOPSIG (status));
1594 if (debug_linux_nat)
1595 fprintf_unfiltered (gdb_stdlog,
1596 "LND: Sending signal %s to %s\n",
1598 target_pid_to_str (main_lwp->ptid));
1601 if (linux_nat_prepare_to_resume != NULL)
1602 linux_nat_prepare_to_resume (main_lwp);
1603 delete_lwp (main_lwp->ptid);
1605 if (forks_exist_p ())
1607 /* Multi-fork case. The current inferior_ptid is being detached
1608 from, but there are other viable forks to debug. Detach from
1609 the current fork, and context-switch to the first
1611 linux_fork_detach (args, from_tty);
1614 linux_ops->to_detach (ops, args, from_tty);
1620 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1624 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
1626 if (inf->vfork_child != NULL)
1628 if (debug_linux_nat)
1629 fprintf_unfiltered (gdb_stdlog,
1630 "RC: Not resuming %s (vfork parent)\n",
1631 target_pid_to_str (lp->ptid));
1633 else if (lp->status == 0
1634 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
1636 if (debug_linux_nat)
1637 fprintf_unfiltered (gdb_stdlog,
1638 "RC: Resuming sibling %s, %s, %s\n",
1639 target_pid_to_str (lp->ptid),
1640 (signo != GDB_SIGNAL_0
1641 ? strsignal (gdb_signal_to_host (signo))
1643 step ? "step" : "resume");
1645 if (linux_nat_prepare_to_resume != NULL)
1646 linux_nat_prepare_to_resume (lp);
1647 linux_ops->to_resume (linux_ops,
1648 pid_to_ptid (ptid_get_lwp (lp->ptid)),
1652 lp->stopped_by_watchpoint = 0;
1656 if (debug_linux_nat)
1657 fprintf_unfiltered (gdb_stdlog,
1658 "RC: Not resuming sibling %s (has pending)\n",
1659 target_pid_to_str (lp->ptid));
1664 if (debug_linux_nat)
1665 fprintf_unfiltered (gdb_stdlog,
1666 "RC: Not resuming sibling %s (not stopped)\n",
1667 target_pid_to_str (lp->ptid));
1671 /* Resume LWP, with the last stop signal, if it is in pass state. */
1674 linux_nat_resume_callback (struct lwp_info *lp, void *data)
1676 enum gdb_signal signo = GDB_SIGNAL_0;
1680 struct thread_info *thread;
1682 thread = find_thread_ptid (lp->ptid);
1685 if (signal_pass_state (thread->suspend.stop_signal))
1686 signo = thread->suspend.stop_signal;
1687 thread->suspend.stop_signal = GDB_SIGNAL_0;
1691 resume_lwp (lp, 0, signo);
1696 resume_clear_callback (struct lwp_info *lp, void *data)
1699 lp->last_resume_kind = resume_stop;
1704 resume_set_callback (struct lwp_info *lp, void *data)
1707 lp->last_resume_kind = resume_continue;
1712 linux_nat_resume (struct target_ops *ops,
1713 ptid_t ptid, int step, enum gdb_signal signo)
1715 struct lwp_info *lp;
1718 if (debug_linux_nat)
1719 fprintf_unfiltered (gdb_stdlog,
1720 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1721 step ? "step" : "resume",
1722 target_pid_to_str (ptid),
1723 (signo != GDB_SIGNAL_0
1724 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1725 target_pid_to_str (inferior_ptid));
1727 /* A specific PTID means `step only this process id'. */
1728 resume_many = (ptid_equal (minus_one_ptid, ptid)
1729 || ptid_is_pid (ptid));
1731 /* Mark the lwps we're resuming as resumed. */
1732 iterate_over_lwps (ptid, resume_set_callback, NULL);
1734 /* See if it's the current inferior that should be handled
1737 lp = find_lwp_pid (inferior_ptid);
1739 lp = find_lwp_pid (ptid);
1740 gdb_assert (lp != NULL);
1742 /* Remember if we're stepping. */
1744 lp->last_resume_kind = step ? resume_step : resume_continue;
1746 /* If we have a pending wait status for this thread, there is no
1747 point in resuming the process. But first make sure that
1748 linux_nat_wait won't preemptively handle the event - we
1749 should never take this short-circuit if we are going to
1750 leave LP running, since we have skipped resuming all the
1751 other threads. This bit of code needs to be synchronized
1752 with linux_nat_wait. */
1754 if (lp->status && WIFSTOPPED (lp->status))
1757 && WSTOPSIG (lp->status)
1758 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1760 if (debug_linux_nat)
1761 fprintf_unfiltered (gdb_stdlog,
1762 "LLR: Not short circuiting for ignored "
1763 "status 0x%x\n", lp->status);
1765 /* FIXME: What should we do if we are supposed to continue
1766 this thread with a signal? */
1767 gdb_assert (signo == GDB_SIGNAL_0);
1768 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1773 if (lp->status || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1775 /* FIXME: What should we do if we are supposed to continue
1776 this thread with a signal? */
1777 gdb_assert (signo == GDB_SIGNAL_0);
1779 if (debug_linux_nat)
1780 fprintf_unfiltered (gdb_stdlog,
1781 "LLR: Short circuiting for status 0x%x\n",
1784 if (target_can_async_p ())
1786 target_async (inferior_event_handler, 0);
1787 /* Tell the event loop we have something to process. */
1793 /* Mark LWP as not stopped to prevent it from being continued by
1794 linux_nat_resume_callback. */
1798 iterate_over_lwps (ptid, linux_nat_resume_callback, NULL);
1800 /* Convert to something the lower layer understands. */
1801 ptid = pid_to_ptid (ptid_get_lwp (lp->ptid));
1803 if (linux_nat_prepare_to_resume != NULL)
1804 linux_nat_prepare_to_resume (lp);
1805 linux_ops->to_resume (linux_ops, ptid, step, signo);
1806 lp->stopped_by_watchpoint = 0;
1808 if (debug_linux_nat)
1809 fprintf_unfiltered (gdb_stdlog,
1810 "LLR: %s %s, %s (resume event thread)\n",
1811 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1812 target_pid_to_str (ptid),
1813 (signo != GDB_SIGNAL_0
1814 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1816 if (target_can_async_p ())
1817 target_async (inferior_event_handler, 0);
1820 /* Send a signal to an LWP. */
1823 kill_lwp (int lwpid, int signo)
1825 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1826 fails, then we are not using nptl threads and we should be using kill. */
1828 #ifdef HAVE_TKILL_SYSCALL
1830 static int tkill_failed;
1837 ret = syscall (__NR_tkill, lwpid, signo);
1838 if (errno != ENOSYS)
1845 return kill (lwpid, signo);
1848 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1849 event, check if the core is interested in it: if not, ignore the
1850 event, and keep waiting; otherwise, we need to toggle the LWP's
1851 syscall entry/exit status, since the ptrace event itself doesn't
1852 indicate it, and report the trap to higher layers. */
1855 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1857 struct target_waitstatus *ourstatus = &lp->waitstatus;
1858 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1859 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1863 /* If we're stopping threads, there's a SIGSTOP pending, which
1864 makes it so that the LWP reports an immediate syscall return,
1865 followed by the SIGSTOP. Skip seeing that "return" using
1866 PTRACE_CONT directly, and let stop_wait_callback collect the
1867 SIGSTOP. Later when the thread is resumed, a new syscall
1868 entry event. If we didn't do this (and returned 0), we'd
1869 leave a syscall entry pending, and our caller, by using
1870 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1871 itself. Later, when the user re-resumes this LWP, we'd see
1872 another syscall entry event and we'd mistake it for a return.
1874 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1875 (leaving immediately with LWP->signalled set, without issuing
1876 a PTRACE_CONT), it would still be problematic to leave this
1877 syscall enter pending, as later when the thread is resumed,
1878 it would then see the same syscall exit mentioned above,
1879 followed by the delayed SIGSTOP, while the syscall didn't
1880 actually get to execute. It seems it would be even more
1881 confusing to the user. */
1883 if (debug_linux_nat)
1884 fprintf_unfiltered (gdb_stdlog,
1885 "LHST: ignoring syscall %d "
1886 "for LWP %ld (stopping threads), "
1887 "resuming with PTRACE_CONT for SIGSTOP\n",
1889 ptid_get_lwp (lp->ptid));
1891 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1892 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1896 if (catch_syscall_enabled ())
1898 /* Always update the entry/return state, even if this particular
1899 syscall isn't interesting to the core now. In async mode,
1900 the user could install a new catchpoint for this syscall
1901 between syscall enter/return, and we'll need to know to
1902 report a syscall return if that happens. */
1903 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1904 ? TARGET_WAITKIND_SYSCALL_RETURN
1905 : TARGET_WAITKIND_SYSCALL_ENTRY);
1907 if (catching_syscall_number (syscall_number))
1909 /* Alright, an event to report. */
1910 ourstatus->kind = lp->syscall_state;
1911 ourstatus->value.syscall_number = syscall_number;
1913 if (debug_linux_nat)
1914 fprintf_unfiltered (gdb_stdlog,
1915 "LHST: stopping for %s of syscall %d"
1918 == TARGET_WAITKIND_SYSCALL_ENTRY
1919 ? "entry" : "return",
1921 ptid_get_lwp (lp->ptid));
1925 if (debug_linux_nat)
1926 fprintf_unfiltered (gdb_stdlog,
1927 "LHST: ignoring %s of syscall %d "
1929 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1930 ? "entry" : "return",
1932 ptid_get_lwp (lp->ptid));
1936 /* If we had been syscall tracing, and hence used PT_SYSCALL
1937 before on this LWP, it could happen that the user removes all
1938 syscall catchpoints before we get to process this event.
1939 There are two noteworthy issues here:
1941 - When stopped at a syscall entry event, resuming with
1942 PT_STEP still resumes executing the syscall and reports a
1945 - Only PT_SYSCALL catches syscall enters. If we last
1946 single-stepped this thread, then this event can't be a
1947 syscall enter. If we last single-stepped this thread, this
1948 has to be a syscall exit.
1950 The points above mean that the next resume, be it PT_STEP or
1951 PT_CONTINUE, can not trigger a syscall trace event. */
1952 if (debug_linux_nat)
1953 fprintf_unfiltered (gdb_stdlog,
1954 "LHST: caught syscall event "
1955 "with no syscall catchpoints."
1956 " %d for LWP %ld, ignoring\n",
1958 ptid_get_lwp (lp->ptid));
1959 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1962 /* The core isn't interested in this event. For efficiency, avoid
1963 stopping all threads only to have the core resume them all again.
1964 Since we're not stopping threads, if we're still syscall tracing
1965 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1966 subsequent syscall. Simply resume using the inf-ptrace layer,
1967 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1969 /* Note that gdbarch_get_syscall_number may access registers, hence
1971 registers_changed ();
1972 if (linux_nat_prepare_to_resume != NULL)
1973 linux_nat_prepare_to_resume (lp);
1974 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
1975 lp->step, GDB_SIGNAL_0);
1979 /* Handle a GNU/Linux extended wait response. If we see a clone
1980 event, we need to add the new LWP to our list (and not report the
1981 trap to higher layers). This function returns non-zero if the
1982 event should be ignored and we should wait again. If STOPPING is
1983 true, the new LWP remains stopped, otherwise it is continued. */
1986 linux_handle_extended_wait (struct lwp_info *lp, int status,
1989 int pid = ptid_get_lwp (lp->ptid);
1990 struct target_waitstatus *ourstatus = &lp->waitstatus;
1991 int event = status >> 16;
1993 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1994 || event == PTRACE_EVENT_CLONE)
1996 unsigned long new_pid;
1999 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
2001 /* If we haven't already seen the new PID stop, wait for it now. */
2002 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
2004 /* The new child has a pending SIGSTOP. We can't affect it until it
2005 hits the SIGSTOP, but we're already attached. */
2006 ret = my_waitpid (new_pid, &status,
2007 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
2009 perror_with_name (_("waiting for new child"));
2010 else if (ret != new_pid)
2011 internal_error (__FILE__, __LINE__,
2012 _("wait returned unexpected PID %d"), ret);
2013 else if (!WIFSTOPPED (status))
2014 internal_error (__FILE__, __LINE__,
2015 _("wait returned unexpected status 0x%x"), status);
2018 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
2020 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
2022 /* The arch-specific native code may need to know about new
2023 forks even if those end up never mapped to an
2025 if (linux_nat_new_fork != NULL)
2026 linux_nat_new_fork (lp, new_pid);
2029 if (event == PTRACE_EVENT_FORK
2030 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
2032 /* Handle checkpointing by linux-fork.c here as a special
2033 case. We don't want the follow-fork-mode or 'catch fork'
2034 to interfere with this. */
2036 /* This won't actually modify the breakpoint list, but will
2037 physically remove the breakpoints from the child. */
2038 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
2040 /* Retain child fork in ptrace (stopped) state. */
2041 if (!find_fork_pid (new_pid))
2044 /* Report as spurious, so that infrun doesn't want to follow
2045 this fork. We're actually doing an infcall in
2047 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
2049 /* Report the stop to the core. */
2053 if (event == PTRACE_EVENT_FORK)
2054 ourstatus->kind = TARGET_WAITKIND_FORKED;
2055 else if (event == PTRACE_EVENT_VFORK)
2056 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2059 struct lwp_info *new_lp;
2061 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2063 if (debug_linux_nat)
2064 fprintf_unfiltered (gdb_stdlog,
2065 "LHEW: Got clone event "
2066 "from LWP %d, new child is LWP %ld\n",
2069 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
2071 new_lp->stopped = 1;
2073 if (WSTOPSIG (status) != SIGSTOP)
2075 /* This can happen if someone starts sending signals to
2076 the new thread before it gets a chance to run, which
2077 have a lower number than SIGSTOP (e.g. SIGUSR1).
2078 This is an unlikely case, and harder to handle for
2079 fork / vfork than for clone, so we do not try - but
2080 we handle it for clone events here. We'll send
2081 the other signal on to the thread below. */
2083 new_lp->signalled = 1;
2087 struct thread_info *tp;
2089 /* When we stop for an event in some other thread, and
2090 pull the thread list just as this thread has cloned,
2091 we'll have seen the new thread in the thread_db list
2092 before handling the CLONE event (glibc's
2093 pthread_create adds the new thread to the thread list
2094 before clone'ing, and has the kernel fill in the
2095 thread's tid on the clone call with
2096 CLONE_PARENT_SETTID). If that happened, and the core
2097 had requested the new thread to stop, we'll have
2098 killed it with SIGSTOP. But since SIGSTOP is not an
2099 RT signal, it can only be queued once. We need to be
2100 careful to not resume the LWP if we wanted it to
2101 stop. In that case, we'll leave the SIGSTOP pending.
2102 It will later be reported as GDB_SIGNAL_0. */
2103 tp = find_thread_ptid (new_lp->ptid);
2104 if (tp != NULL && tp->stop_requested)
2105 new_lp->last_resume_kind = resume_stop;
2112 /* Add the new thread to GDB's lists as soon as possible
2115 1) the frontend doesn't have to wait for a stop to
2118 2) we tag it with the correct running state. */
2120 /* If the thread_db layer is active, let it know about
2121 this new thread, and add it to GDB's list. */
2122 if (!thread_db_attach_lwp (new_lp->ptid))
2124 /* We're not using thread_db. Add it to GDB's
2126 target_post_attach (ptid_get_lwp (new_lp->ptid));
2127 add_thread (new_lp->ptid);
2132 set_running (new_lp->ptid, 1);
2133 set_executing (new_lp->ptid, 1);
2134 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2136 new_lp->last_resume_kind = resume_continue;
2142 /* We created NEW_LP so it cannot yet contain STATUS. */
2143 gdb_assert (new_lp->status == 0);
2145 /* Save the wait status to report later. */
2146 if (debug_linux_nat)
2147 fprintf_unfiltered (gdb_stdlog,
2148 "LHEW: waitpid of new LWP %ld, "
2149 "saving status %s\n",
2150 (long) ptid_get_lwp (new_lp->ptid),
2151 status_to_str (status));
2152 new_lp->status = status;
2155 /* Note the need to use the low target ops to resume, to
2156 handle resuming with PT_SYSCALL if we have syscall
2160 new_lp->resumed = 1;
2164 gdb_assert (new_lp->last_resume_kind == resume_continue);
2165 if (debug_linux_nat)
2166 fprintf_unfiltered (gdb_stdlog,
2167 "LHEW: resuming new LWP %ld\n",
2168 ptid_get_lwp (new_lp->ptid));
2169 if (linux_nat_prepare_to_resume != NULL)
2170 linux_nat_prepare_to_resume (new_lp);
2171 linux_ops->to_resume (linux_ops, pid_to_ptid (new_pid),
2173 new_lp->stopped = 0;
2177 if (debug_linux_nat)
2178 fprintf_unfiltered (gdb_stdlog,
2179 "LHEW: resuming parent LWP %d\n", pid);
2180 if (linux_nat_prepare_to_resume != NULL)
2181 linux_nat_prepare_to_resume (lp);
2182 linux_ops->to_resume (linux_ops,
2183 pid_to_ptid (ptid_get_lwp (lp->ptid)),
2192 if (event == PTRACE_EVENT_EXEC)
2194 if (debug_linux_nat)
2195 fprintf_unfiltered (gdb_stdlog,
2196 "LHEW: Got exec event from LWP %ld\n",
2197 ptid_get_lwp (lp->ptid));
2199 ourstatus->kind = TARGET_WAITKIND_EXECD;
2200 ourstatus->value.execd_pathname
2201 = xstrdup (linux_child_pid_to_exec_file (pid));
2206 if (event == PTRACE_EVENT_VFORK_DONE)
2208 if (current_inferior ()->waiting_for_vfork_done)
2210 if (debug_linux_nat)
2211 fprintf_unfiltered (gdb_stdlog,
2212 "LHEW: Got expected PTRACE_EVENT_"
2213 "VFORK_DONE from LWP %ld: stopping\n",
2214 ptid_get_lwp (lp->ptid));
2216 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2220 if (debug_linux_nat)
2221 fprintf_unfiltered (gdb_stdlog,
2222 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2223 "from LWP %ld: resuming\n",
2224 ptid_get_lwp (lp->ptid));
2225 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2229 internal_error (__FILE__, __LINE__,
2230 _("unknown ptrace event %d"), event);
2233 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2237 wait_lwp (struct lwp_info *lp)
2241 int thread_dead = 0;
2244 gdb_assert (!lp->stopped);
2245 gdb_assert (lp->status == 0);
2247 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2248 block_child_signals (&prev_mask);
2252 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2253 was right and we should just call sigsuspend. */
2255 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2256 if (pid == -1 && errno == ECHILD)
2257 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2258 if (pid == -1 && errno == ECHILD)
2260 /* The thread has previously exited. We need to delete it
2261 now because, for some vendor 2.4 kernels with NPTL
2262 support backported, there won't be an exit event unless
2263 it is the main thread. 2.6 kernels will report an exit
2264 event for each thread that exits, as expected. */
2266 if (debug_linux_nat)
2267 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2268 target_pid_to_str (lp->ptid));
2273 /* Bugs 10970, 12702.
2274 Thread group leader may have exited in which case we'll lock up in
2275 waitpid if there are other threads, even if they are all zombies too.
2276 Basically, we're not supposed to use waitpid this way.
2277 __WCLONE is not applicable for the leader so we can't use that.
2278 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2279 process; it gets ESRCH both for the zombie and for running processes.
2281 As a workaround, check if we're waiting for the thread group leader and
2282 if it's a zombie, and avoid calling waitpid if it is.
2284 This is racy, what if the tgl becomes a zombie right after we check?
2285 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2286 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2288 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2289 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2292 if (debug_linux_nat)
2293 fprintf_unfiltered (gdb_stdlog,
2294 "WL: Thread group leader %s vanished.\n",
2295 target_pid_to_str (lp->ptid));
2299 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2300 get invoked despite our caller had them intentionally blocked by
2301 block_child_signals. This is sensitive only to the loop of
2302 linux_nat_wait_1 and there if we get called my_waitpid gets called
2303 again before it gets to sigsuspend so we can safely let the handlers
2304 get executed here. */
2306 sigsuspend (&suspend_mask);
2309 restore_child_signals_mask (&prev_mask);
2313 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2315 if (debug_linux_nat)
2317 fprintf_unfiltered (gdb_stdlog,
2318 "WL: waitpid %s received %s\n",
2319 target_pid_to_str (lp->ptid),
2320 status_to_str (status));
2323 /* Check if the thread has exited. */
2324 if (WIFEXITED (status) || WIFSIGNALED (status))
2327 if (debug_linux_nat)
2328 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2329 target_pid_to_str (lp->ptid));
2339 gdb_assert (WIFSTOPPED (status));
2341 /* Handle GNU/Linux's syscall SIGTRAPs. */
2342 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2344 /* No longer need the sysgood bit. The ptrace event ends up
2345 recorded in lp->waitstatus if we care for it. We can carry
2346 on handling the event like a regular SIGTRAP from here
2348 status = W_STOPCODE (SIGTRAP);
2349 if (linux_handle_syscall_trap (lp, 1))
2350 return wait_lwp (lp);
2353 /* Handle GNU/Linux's extended waitstatus for trace events. */
2354 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2356 if (debug_linux_nat)
2357 fprintf_unfiltered (gdb_stdlog,
2358 "WL: Handling extended status 0x%06x\n",
2360 if (linux_handle_extended_wait (lp, status, 1))
2361 return wait_lwp (lp);
2367 /* Send a SIGSTOP to LP. */
2370 stop_callback (struct lwp_info *lp, void *data)
2372 if (!lp->stopped && !lp->signalled)
2376 if (debug_linux_nat)
2378 fprintf_unfiltered (gdb_stdlog,
2379 "SC: kill %s **<SIGSTOP>**\n",
2380 target_pid_to_str (lp->ptid));
2383 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2384 if (debug_linux_nat)
2386 fprintf_unfiltered (gdb_stdlog,
2387 "SC: lwp kill %d %s\n",
2389 errno ? safe_strerror (errno) : "ERRNO-OK");
2393 gdb_assert (lp->status == 0);
2399 /* Request a stop on LWP. */
2402 linux_stop_lwp (struct lwp_info *lwp)
2404 stop_callback (lwp, NULL);
2407 /* Return non-zero if LWP PID has a pending SIGINT. */
2410 linux_nat_has_pending_sigint (int pid)
2412 sigset_t pending, blocked, ignored;
2414 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2416 if (sigismember (&pending, SIGINT)
2417 && !sigismember (&ignored, SIGINT))
2423 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2426 set_ignore_sigint (struct lwp_info *lp, void *data)
2428 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2429 flag to consume the next one. */
2430 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2431 && WSTOPSIG (lp->status) == SIGINT)
2434 lp->ignore_sigint = 1;
2439 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2440 This function is called after we know the LWP has stopped; if the LWP
2441 stopped before the expected SIGINT was delivered, then it will never have
2442 arrived. Also, if the signal was delivered to a shared queue and consumed
2443 by a different thread, it will never be delivered to this LWP. */
2446 maybe_clear_ignore_sigint (struct lwp_info *lp)
2448 if (!lp->ignore_sigint)
2451 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2453 if (debug_linux_nat)
2454 fprintf_unfiltered (gdb_stdlog,
2455 "MCIS: Clearing bogus flag for %s\n",
2456 target_pid_to_str (lp->ptid));
2457 lp->ignore_sigint = 0;
2461 /* Fetch the possible triggered data watchpoint info and store it in
2464 On some archs, like x86, that use debug registers to set
2465 watchpoints, it's possible that the way to know which watched
2466 address trapped, is to check the register that is used to select
2467 which address to watch. Problem is, between setting the watchpoint
2468 and reading back which data address trapped, the user may change
2469 the set of watchpoints, and, as a consequence, GDB changes the
2470 debug registers in the inferior. To avoid reading back a stale
2471 stopped-data-address when that happens, we cache in LP the fact
2472 that a watchpoint trapped, and the corresponding data address, as
2473 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2474 registers meanwhile, we have the cached data we can rely on. */
2477 save_sigtrap (struct lwp_info *lp)
2479 struct cleanup *old_chain;
2481 if (linux_ops->to_stopped_by_watchpoint == NULL)
2483 lp->stopped_by_watchpoint = 0;
2487 old_chain = save_inferior_ptid ();
2488 inferior_ptid = lp->ptid;
2490 lp->stopped_by_watchpoint = linux_ops->to_stopped_by_watchpoint ();
2492 if (lp->stopped_by_watchpoint)
2494 if (linux_ops->to_stopped_data_address != NULL)
2495 lp->stopped_data_address_p =
2496 linux_ops->to_stopped_data_address (¤t_target,
2497 &lp->stopped_data_address);
2499 lp->stopped_data_address_p = 0;
2502 do_cleanups (old_chain);
2505 /* See save_sigtrap. */
2508 linux_nat_stopped_by_watchpoint (void)
2510 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2512 gdb_assert (lp != NULL);
2514 return lp->stopped_by_watchpoint;
2518 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2520 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2522 gdb_assert (lp != NULL);
2524 *addr_p = lp->stopped_data_address;
2526 return lp->stopped_data_address_p;
2529 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2532 sigtrap_is_event (int status)
2534 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2537 /* SIGTRAP-like events recognizer. */
2539 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
2541 /* Check for SIGTRAP-like events in LP. */
2544 linux_nat_lp_status_is_event (struct lwp_info *lp)
2546 /* We check for lp->waitstatus in addition to lp->status, because we can
2547 have pending process exits recorded in lp->status
2548 and W_EXITCODE(0,0) == 0. We should probably have an additional
2549 lp->status_p flag. */
2551 return (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE
2552 && linux_nat_status_is_event (lp->status));
2555 /* Set alternative SIGTRAP-like events recognizer. If
2556 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2560 linux_nat_set_status_is_event (struct target_ops *t,
2561 int (*status_is_event) (int status))
2563 linux_nat_status_is_event = status_is_event;
2566 /* Wait until LP is stopped. */
2569 stop_wait_callback (struct lwp_info *lp, void *data)
2571 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2573 /* If this is a vfork parent, bail out, it is not going to report
2574 any SIGSTOP until the vfork is done with. */
2575 if (inf->vfork_child != NULL)
2582 status = wait_lwp (lp);
2586 if (lp->ignore_sigint && WIFSTOPPED (status)
2587 && WSTOPSIG (status) == SIGINT)
2589 lp->ignore_sigint = 0;
2592 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2593 if (debug_linux_nat)
2594 fprintf_unfiltered (gdb_stdlog,
2595 "PTRACE_CONT %s, 0, 0 (%s) "
2596 "(discarding SIGINT)\n",
2597 target_pid_to_str (lp->ptid),
2598 errno ? safe_strerror (errno) : "OK");
2600 return stop_wait_callback (lp, NULL);
2603 maybe_clear_ignore_sigint (lp);
2605 if (WSTOPSIG (status) != SIGSTOP)
2607 /* The thread was stopped with a signal other than SIGSTOP. */
2611 if (debug_linux_nat)
2612 fprintf_unfiltered (gdb_stdlog,
2613 "SWC: Pending event %s in %s\n",
2614 status_to_str ((int) status),
2615 target_pid_to_str (lp->ptid));
2617 /* Save the sigtrap event. */
2618 lp->status = status;
2619 gdb_assert (!lp->stopped);
2620 gdb_assert (lp->signalled);
2625 /* We caught the SIGSTOP that we intended to catch, so
2626 there's no SIGSTOP pending. */
2628 if (debug_linux_nat)
2629 fprintf_unfiltered (gdb_stdlog,
2630 "SWC: Delayed SIGSTOP caught for %s.\n",
2631 target_pid_to_str (lp->ptid));
2635 /* Reset SIGNALLED only after the stop_wait_callback call
2636 above as it does gdb_assert on SIGNALLED. */
2644 /* Return non-zero if LP has a wait status pending. */
2647 status_callback (struct lwp_info *lp, void *data)
2649 /* Only report a pending wait status if we pretend that this has
2650 indeed been resumed. */
2654 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2656 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2657 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2658 0', so a clean process exit can not be stored pending in
2659 lp->status, it is indistinguishable from
2660 no-pending-status. */
2664 if (lp->status != 0)
2670 /* Return non-zero if LP isn't stopped. */
2673 running_callback (struct lwp_info *lp, void *data)
2675 return (!lp->stopped
2676 || ((lp->status != 0
2677 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2681 /* Count the LWP's that have had events. */
2684 count_events_callback (struct lwp_info *lp, void *data)
2688 gdb_assert (count != NULL);
2690 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2691 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2697 /* Select the LWP (if any) that is currently being single-stepped. */
2700 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2702 if (lp->last_resume_kind == resume_step
2709 /* Select the Nth LWP that has had a SIGTRAP event. */
2712 select_event_lwp_callback (struct lwp_info *lp, void *data)
2714 int *selector = data;
2716 gdb_assert (selector != NULL);
2718 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2719 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2720 if ((*selector)-- == 0)
2727 cancel_breakpoint (struct lwp_info *lp)
2729 /* Arrange for a breakpoint to be hit again later. We don't keep
2730 the SIGTRAP status and don't forward the SIGTRAP signal to the
2731 LWP. We will handle the current event, eventually we will resume
2732 this LWP, and this breakpoint will trap again.
2734 If we do not do this, then we run the risk that the user will
2735 delete or disable the breakpoint, but the LWP will have already
2738 struct regcache *regcache = get_thread_regcache (lp->ptid);
2739 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2742 pc = regcache_read_pc (regcache) - gdbarch_decr_pc_after_break (gdbarch);
2743 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2745 if (debug_linux_nat)
2746 fprintf_unfiltered (gdb_stdlog,
2747 "CB: Push back breakpoint for %s\n",
2748 target_pid_to_str (lp->ptid));
2750 /* Back up the PC if necessary. */
2751 if (gdbarch_decr_pc_after_break (gdbarch))
2752 regcache_write_pc (regcache, pc);
2760 cancel_breakpoints_callback (struct lwp_info *lp, void *data)
2762 struct lwp_info *event_lp = data;
2764 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2768 /* If a LWP other than the LWP that we're reporting an event for has
2769 hit a GDB breakpoint (as opposed to some random trap signal),
2770 then just arrange for it to hit it again later. We don't keep
2771 the SIGTRAP status and don't forward the SIGTRAP signal to the
2772 LWP. We will handle the current event, eventually we will resume
2773 all LWPs, and this one will get its breakpoint trap again.
2775 If we do not do this, then we run the risk that the user will
2776 delete or disable the breakpoint, but the LWP will have already
2779 if (linux_nat_lp_status_is_event (lp)
2780 && cancel_breakpoint (lp))
2781 /* Throw away the SIGTRAP. */
2787 /* Select one LWP out of those that have events pending. */
2790 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2793 int random_selector;
2794 struct lwp_info *event_lp;
2796 /* Record the wait status for the original LWP. */
2797 (*orig_lp)->status = *status;
2799 /* Give preference to any LWP that is being single-stepped. */
2800 event_lp = iterate_over_lwps (filter,
2801 select_singlestep_lwp_callback, NULL);
2802 if (event_lp != NULL)
2804 if (debug_linux_nat)
2805 fprintf_unfiltered (gdb_stdlog,
2806 "SEL: Select single-step %s\n",
2807 target_pid_to_str (event_lp->ptid));
2811 /* No single-stepping LWP. Select one at random, out of those
2812 which have had SIGTRAP events. */
2814 /* First see how many SIGTRAP events we have. */
2815 iterate_over_lwps (filter, count_events_callback, &num_events);
2817 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2818 random_selector = (int)
2819 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2821 if (debug_linux_nat && num_events > 1)
2822 fprintf_unfiltered (gdb_stdlog,
2823 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2824 num_events, random_selector);
2826 event_lp = iterate_over_lwps (filter,
2827 select_event_lwp_callback,
2831 if (event_lp != NULL)
2833 /* Switch the event LWP. */
2834 *orig_lp = event_lp;
2835 *status = event_lp->status;
2838 /* Flush the wait status for the event LWP. */
2839 (*orig_lp)->status = 0;
2842 /* Return non-zero if LP has been resumed. */
2845 resumed_callback (struct lwp_info *lp, void *data)
2850 /* Stop an active thread, verify it still exists, then resume it. If
2851 the thread ends up with a pending status, then it is not resumed,
2852 and *DATA (really a pointer to int), is set. */
2855 stop_and_resume_callback (struct lwp_info *lp, void *data)
2857 int *new_pending_p = data;
2861 ptid_t ptid = lp->ptid;
2863 stop_callback (lp, NULL);
2864 stop_wait_callback (lp, NULL);
2866 /* Resume if the lwp still exists, and the core wanted it
2868 lp = find_lwp_pid (ptid);
2871 if (lp->last_resume_kind == resume_stop
2874 /* The core wanted the LWP to stop. Even if it stopped
2875 cleanly (with SIGSTOP), leave the event pending. */
2876 if (debug_linux_nat)
2877 fprintf_unfiltered (gdb_stdlog,
2878 "SARC: core wanted LWP %ld stopped "
2879 "(leaving SIGSTOP pending)\n",
2880 ptid_get_lwp (lp->ptid));
2881 lp->status = W_STOPCODE (SIGSTOP);
2884 if (lp->status == 0)
2886 if (debug_linux_nat)
2887 fprintf_unfiltered (gdb_stdlog,
2888 "SARC: re-resuming LWP %ld\n",
2889 ptid_get_lwp (lp->ptid));
2890 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2894 if (debug_linux_nat)
2895 fprintf_unfiltered (gdb_stdlog,
2896 "SARC: not re-resuming LWP %ld "
2898 ptid_get_lwp (lp->ptid));
2907 /* Check if we should go on and pass this event to common code.
2908 Return the affected lwp if we are, or NULL otherwise. If we stop
2909 all lwps temporarily, we may end up with new pending events in some
2910 other lwp. In that case set *NEW_PENDING_P to true. */
2912 static struct lwp_info *
2913 linux_nat_filter_event (int lwpid, int status, int *new_pending_p)
2915 struct lwp_info *lp;
2919 lp = find_lwp_pid (pid_to_ptid (lwpid));
2921 /* Check for stop events reported by a process we didn't already
2922 know about - anything not already in our LWP list.
2924 If we're expecting to receive stopped processes after
2925 fork, vfork, and clone events, then we'll just add the
2926 new one to our list and go back to waiting for the event
2927 to be reported - the stopped process might be returned
2928 from waitpid before or after the event is.
2930 But note the case of a non-leader thread exec'ing after the
2931 leader having exited, and gone from our lists. The non-leader
2932 thread changes its tid to the tgid. */
2934 if (WIFSTOPPED (status) && lp == NULL
2935 && (WSTOPSIG (status) == SIGTRAP && status >> 16 == PTRACE_EVENT_EXEC))
2937 /* A multi-thread exec after we had seen the leader exiting. */
2938 if (debug_linux_nat)
2939 fprintf_unfiltered (gdb_stdlog,
2940 "LLW: Re-adding thread group leader LWP %d.\n",
2943 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2946 add_thread (lp->ptid);
2949 if (WIFSTOPPED (status) && !lp)
2951 add_to_pid_list (&stopped_pids, lwpid, status);
2955 /* Make sure we don't report an event for the exit of an LWP not in
2956 our list, i.e. not part of the current process. This can happen
2957 if we detach from a program we originally forked and then it
2959 if (!WIFSTOPPED (status) && !lp)
2962 /* Handle GNU/Linux's syscall SIGTRAPs. */
2963 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2965 /* No longer need the sysgood bit. The ptrace event ends up
2966 recorded in lp->waitstatus if we care for it. We can carry
2967 on handling the event like a regular SIGTRAP from here
2969 status = W_STOPCODE (SIGTRAP);
2970 if (linux_handle_syscall_trap (lp, 0))
2974 /* Handle GNU/Linux's extended waitstatus for trace events. */
2975 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2977 if (debug_linux_nat)
2978 fprintf_unfiltered (gdb_stdlog,
2979 "LLW: Handling extended status 0x%06x\n",
2981 if (linux_handle_extended_wait (lp, status, 0))
2985 if (linux_nat_status_is_event (status))
2988 /* Check if the thread has exited. */
2989 if ((WIFEXITED (status) || WIFSIGNALED (status))
2990 && num_lwps (ptid_get_pid (lp->ptid)) > 1)
2992 /* If this is the main thread, we must stop all threads and verify
2993 if they are still alive. This is because in the nptl thread model
2994 on Linux 2.4, there is no signal issued for exiting LWPs
2995 other than the main thread. We only get the main thread exit
2996 signal once all child threads have already exited. If we
2997 stop all the threads and use the stop_wait_callback to check
2998 if they have exited we can determine whether this signal
2999 should be ignored or whether it means the end of the debugged
3000 application, regardless of which threading model is being
3002 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
3005 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3006 stop_and_resume_callback, new_pending_p);
3009 if (debug_linux_nat)
3010 fprintf_unfiltered (gdb_stdlog,
3011 "LLW: %s exited.\n",
3012 target_pid_to_str (lp->ptid));
3014 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3016 /* If there is at least one more LWP, then the exit signal
3017 was not the end of the debugged application and should be
3024 /* Check if the current LWP has previously exited. In the nptl
3025 thread model, LWPs other than the main thread do not issue
3026 signals when they exit so we must check whenever the thread has
3027 stopped. A similar check is made in stop_wait_callback(). */
3028 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3030 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3032 if (debug_linux_nat)
3033 fprintf_unfiltered (gdb_stdlog,
3034 "LLW: %s exited.\n",
3035 target_pid_to_str (lp->ptid));
3039 /* Make sure there is at least one thread running. */
3040 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3042 /* Discard the event. */
3046 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3047 an attempt to stop an LWP. */
3049 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3051 if (debug_linux_nat)
3052 fprintf_unfiltered (gdb_stdlog,
3053 "LLW: Delayed SIGSTOP caught for %s.\n",
3054 target_pid_to_str (lp->ptid));
3058 if (lp->last_resume_kind != resume_stop)
3060 /* This is a delayed SIGSTOP. */
3062 registers_changed ();
3064 if (linux_nat_prepare_to_resume != NULL)
3065 linux_nat_prepare_to_resume (lp);
3066 linux_ops->to_resume (linux_ops,
3067 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3068 lp->step, GDB_SIGNAL_0);
3069 if (debug_linux_nat)
3070 fprintf_unfiltered (gdb_stdlog,
3071 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3073 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3074 target_pid_to_str (lp->ptid));
3077 gdb_assert (lp->resumed);
3079 /* Discard the event. */
3084 /* Make sure we don't report a SIGINT that we have already displayed
3085 for another thread. */
3086 if (lp->ignore_sigint
3087 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3089 if (debug_linux_nat)
3090 fprintf_unfiltered (gdb_stdlog,
3091 "LLW: Delayed SIGINT caught for %s.\n",
3092 target_pid_to_str (lp->ptid));
3094 /* This is a delayed SIGINT. */
3095 lp->ignore_sigint = 0;
3097 registers_changed ();
3098 if (linux_nat_prepare_to_resume != NULL)
3099 linux_nat_prepare_to_resume (lp);
3100 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3101 lp->step, GDB_SIGNAL_0);
3102 if (debug_linux_nat)
3103 fprintf_unfiltered (gdb_stdlog,
3104 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3106 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3107 target_pid_to_str (lp->ptid));
3110 gdb_assert (lp->resumed);
3112 /* Discard the event. */
3116 /* An interesting event. */
3118 lp->status = status;
3122 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3123 their exits until all other threads in the group have exited. */
3126 check_zombie_leaders (void)
3128 struct inferior *inf;
3132 struct lwp_info *leader_lp;
3137 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3138 if (leader_lp != NULL
3139 /* Check if there are other threads in the group, as we may
3140 have raced with the inferior simply exiting. */
3141 && num_lwps (inf->pid) > 1
3142 && linux_proc_pid_is_zombie (inf->pid))
3144 if (debug_linux_nat)
3145 fprintf_unfiltered (gdb_stdlog,
3146 "CZL: Thread group leader %d zombie "
3147 "(it exited, or another thread execd).\n",
3150 /* A leader zombie can mean one of two things:
3152 - It exited, and there's an exit status pending
3153 available, or only the leader exited (not the whole
3154 program). In the latter case, we can't waitpid the
3155 leader's exit status until all other threads are gone.
3157 - There are 3 or more threads in the group, and a thread
3158 other than the leader exec'd. On an exec, the Linux
3159 kernel destroys all other threads (except the execing
3160 one) in the thread group, and resets the execing thread's
3161 tid to the tgid. No exit notification is sent for the
3162 execing thread -- from the ptracer's perspective, it
3163 appears as though the execing thread just vanishes.
3164 Until we reap all other threads except the leader and the
3165 execing thread, the leader will be zombie, and the
3166 execing thread will be in `D (disc sleep)'. As soon as
3167 all other threads are reaped, the execing thread changes
3168 it's tid to the tgid, and the previous (zombie) leader
3169 vanishes, giving place to the "new" leader. We could try
3170 distinguishing the exit and exec cases, by waiting once
3171 more, and seeing if something comes out, but it doesn't
3172 sound useful. The previous leader _does_ go away, and
3173 we'll re-add the new one once we see the exec event
3174 (which is just the same as what would happen if the
3175 previous leader did exit voluntarily before some other
3178 if (debug_linux_nat)
3179 fprintf_unfiltered (gdb_stdlog,
3180 "CZL: Thread group leader %d vanished.\n",
3182 exit_lwp (leader_lp);
3188 linux_nat_wait_1 (struct target_ops *ops,
3189 ptid_t ptid, struct target_waitstatus *ourstatus,
3192 static sigset_t prev_mask;
3193 enum resume_kind last_resume_kind;
3194 struct lwp_info *lp;
3197 if (debug_linux_nat)
3198 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3200 /* The first time we get here after starting a new inferior, we may
3201 not have added it to the LWP list yet - this is the earliest
3202 moment at which we know its PID. */
3203 if (ptid_is_pid (inferior_ptid))
3205 /* Upgrade the main thread's ptid. */
3206 thread_change_ptid (inferior_ptid,
3207 ptid_build (ptid_get_pid (inferior_ptid),
3208 ptid_get_pid (inferior_ptid), 0));
3210 lp = add_initial_lwp (inferior_ptid);
3214 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3215 block_child_signals (&prev_mask);
3221 /* First check if there is a LWP with a wait status pending. */
3222 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3224 /* Any LWP in the PTID group that's been resumed will do. */
3225 lp = iterate_over_lwps (ptid, status_callback, NULL);
3228 if (debug_linux_nat && lp->status)
3229 fprintf_unfiltered (gdb_stdlog,
3230 "LLW: Using pending wait status %s for %s.\n",
3231 status_to_str (lp->status),
3232 target_pid_to_str (lp->ptid));
3235 else if (ptid_lwp_p (ptid))
3237 if (debug_linux_nat)
3238 fprintf_unfiltered (gdb_stdlog,
3239 "LLW: Waiting for specific LWP %s.\n",
3240 target_pid_to_str (ptid));
3242 /* We have a specific LWP to check. */
3243 lp = find_lwp_pid (ptid);
3246 if (debug_linux_nat && lp->status)
3247 fprintf_unfiltered (gdb_stdlog,
3248 "LLW: Using pending wait status %s for %s.\n",
3249 status_to_str (lp->status),
3250 target_pid_to_str (lp->ptid));
3252 /* We check for lp->waitstatus in addition to lp->status,
3253 because we can have pending process exits recorded in
3254 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3255 an additional lp->status_p flag. */
3256 if (lp->status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3260 if (!target_can_async_p ())
3262 /* Causes SIGINT to be passed on to the attached process. */
3266 /* But if we don't find a pending event, we'll have to wait. */
3272 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3275 - If the thread group leader exits while other threads in the
3276 thread group still exist, waitpid(TGID, ...) hangs. That
3277 waitpid won't return an exit status until the other threads
3278 in the group are reapped.
3280 - When a non-leader thread execs, that thread just vanishes
3281 without reporting an exit (so we'd hang if we waited for it
3282 explicitly in that case). The exec event is reported to
3286 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3287 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3288 lwpid = my_waitpid (-1, &status, WNOHANG);
3290 if (debug_linux_nat)
3291 fprintf_unfiltered (gdb_stdlog,
3292 "LNW: waitpid(-1, ...) returned %d, %s\n",
3293 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3297 /* If this is true, then we paused LWPs momentarily, and may
3298 now have pending events to handle. */
3301 if (debug_linux_nat)
3303 fprintf_unfiltered (gdb_stdlog,
3304 "LLW: waitpid %ld received %s\n",
3305 (long) lwpid, status_to_str (status));
3308 lp = linux_nat_filter_event (lwpid, status, &new_pending);
3310 /* STATUS is now no longer valid, use LP->STATUS instead. */
3313 if (lp && !ptid_match (lp->ptid, ptid))
3315 gdb_assert (lp->resumed);
3317 if (debug_linux_nat)
3319 "LWP %ld got an event %06x, leaving pending.\n",
3320 ptid_get_lwp (lp->ptid), lp->status);
3322 if (WIFSTOPPED (lp->status))
3324 if (WSTOPSIG (lp->status) != SIGSTOP)
3326 /* Cancel breakpoint hits. The breakpoint may
3327 be removed before we fetch events from this
3328 process to report to the core. It is best
3329 not to assume the moribund breakpoints
3330 heuristic always handles these cases --- it
3331 could be too many events go through to the
3332 core before this one is handled. All-stop
3333 always cancels breakpoint hits in all
3336 && linux_nat_lp_status_is_event (lp)
3337 && cancel_breakpoint (lp))
3339 /* Throw away the SIGTRAP. */
3342 if (debug_linux_nat)
3344 "LLW: LWP %ld hit a breakpoint while"
3345 " waiting for another process;"
3347 ptid_get_lwp (lp->ptid));
3357 else if (WIFEXITED (lp->status) || WIFSIGNALED (lp->status))
3359 if (debug_linux_nat)
3361 "Process %ld exited while stopping LWPs\n",
3362 ptid_get_lwp (lp->ptid));
3364 /* This was the last lwp in the process. Since
3365 events are serialized to GDB core, and we can't
3366 report this one right now, but GDB core and the
3367 other target layers will want to be notified
3368 about the exit code/signal, leave the status
3369 pending for the next time we're able to report
3372 /* Prevent trying to stop this thread again. We'll
3373 never try to resume it because it has a pending
3377 /* Dead LWP's aren't expected to reported a pending
3381 /* Store the pending event in the waitstatus as
3382 well, because W_EXITCODE(0,0) == 0. */
3383 store_waitstatus (&lp->waitstatus, lp->status);
3392 /* Some LWP now has a pending event. Go all the way
3393 back to check it. */
3399 /* We got an event to report to the core. */
3403 /* Retry until nothing comes out of waitpid. A single
3404 SIGCHLD can indicate more than one child stopped. */
3408 /* Check for zombie thread group leaders. Those can't be reaped
3409 until all other threads in the thread group are. */
3410 check_zombie_leaders ();
3412 /* If there are no resumed children left, bail. We'd be stuck
3413 forever in the sigsuspend call below otherwise. */
3414 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3416 if (debug_linux_nat)
3417 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3419 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3421 if (!target_can_async_p ())
3422 clear_sigint_trap ();
3424 restore_child_signals_mask (&prev_mask);
3425 return minus_one_ptid;
3428 /* No interesting event to report to the core. */
3430 if (target_options & TARGET_WNOHANG)
3432 if (debug_linux_nat)
3433 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3435 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3436 restore_child_signals_mask (&prev_mask);
3437 return minus_one_ptid;
3440 /* We shouldn't end up here unless we want to try again. */
3441 gdb_assert (lp == NULL);
3443 /* Block until we get an event reported with SIGCHLD. */
3444 sigsuspend (&suspend_mask);
3447 if (!target_can_async_p ())
3448 clear_sigint_trap ();
3452 status = lp->status;
3455 /* Don't report signals that GDB isn't interested in, such as
3456 signals that are neither printed nor stopped upon. Stopping all
3457 threads can be a bit time-consuming so if we want decent
3458 performance with heavily multi-threaded programs, especially when
3459 they're using a high frequency timer, we'd better avoid it if we
3462 if (WIFSTOPPED (status))
3464 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3466 /* When using hardware single-step, we need to report every signal.
3467 Otherwise, signals in pass_mask may be short-circuited. */
3469 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status)))
3471 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3472 here? It is not clear we should. GDB may not expect
3473 other threads to run. On the other hand, not resuming
3474 newly attached threads may cause an unwanted delay in
3475 getting them running. */
3476 registers_changed ();
3477 if (linux_nat_prepare_to_resume != NULL)
3478 linux_nat_prepare_to_resume (lp);
3479 linux_ops->to_resume (linux_ops,
3480 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3482 if (debug_linux_nat)
3483 fprintf_unfiltered (gdb_stdlog,
3484 "LLW: %s %s, %s (preempt 'handle')\n",
3486 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3487 target_pid_to_str (lp->ptid),
3488 (signo != GDB_SIGNAL_0
3489 ? strsignal (gdb_signal_to_host (signo))
3497 /* Only do the below in all-stop, as we currently use SIGINT
3498 to implement target_stop (see linux_nat_stop) in
3500 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3502 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3503 forwarded to the entire process group, that is, all LWPs
3504 will receive it - unless they're using CLONE_THREAD to
3505 share signals. Since we only want to report it once, we
3506 mark it as ignored for all LWPs except this one. */
3507 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)),
3508 set_ignore_sigint, NULL);
3509 lp->ignore_sigint = 0;
3512 maybe_clear_ignore_sigint (lp);
3516 /* This LWP is stopped now. */
3519 if (debug_linux_nat)
3520 fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
3521 status_to_str (status), target_pid_to_str (lp->ptid));
3525 /* Now stop all other LWP's ... */
3526 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3528 /* ... and wait until all of them have reported back that
3529 they're no longer running. */
3530 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3532 /* If we're not waiting for a specific LWP, choose an event LWP
3533 from among those that have had events. Giving equal priority
3534 to all LWPs that have had events helps prevent
3536 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3537 select_event_lwp (ptid, &lp, &status);
3539 /* Now that we've selected our final event LWP, cancel any
3540 breakpoints in other LWPs that have hit a GDB breakpoint.
3541 See the comment in cancel_breakpoints_callback to find out
3543 iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp);
3545 /* We'll need this to determine whether to report a SIGSTOP as
3546 TARGET_WAITKIND_0. Need to take a copy because
3547 resume_clear_callback clears it. */
3548 last_resume_kind = lp->last_resume_kind;
3550 /* In all-stop, from the core's perspective, all LWPs are now
3551 stopped until a new resume action is sent over. */
3552 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3557 last_resume_kind = lp->last_resume_kind;
3558 resume_clear_callback (lp, NULL);
3561 if (linux_nat_status_is_event (status))
3563 if (debug_linux_nat)
3564 fprintf_unfiltered (gdb_stdlog,
3565 "LLW: trap ptid is %s.\n",
3566 target_pid_to_str (lp->ptid));
3569 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3571 *ourstatus = lp->waitstatus;
3572 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3575 store_waitstatus (ourstatus, status);
3577 if (debug_linux_nat)
3578 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3580 restore_child_signals_mask (&prev_mask);
3582 if (last_resume_kind == resume_stop
3583 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3584 && WSTOPSIG (status) == SIGSTOP)
3586 /* A thread that has been requested to stop by GDB with
3587 target_stop, and it stopped cleanly, so report as SIG0. The
3588 use of SIGSTOP is an implementation detail. */
3589 ourstatus->value.sig = GDB_SIGNAL_0;
3592 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3593 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3596 lp->core = linux_common_core_of_thread (lp->ptid);
3601 /* Resume LWPs that are currently stopped without any pending status
3602 to report, but are resumed from the core's perspective. */
3605 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3607 ptid_t *wait_ptid_p = data;
3612 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3614 struct regcache *regcache = get_thread_regcache (lp->ptid);
3615 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3616 CORE_ADDR pc = regcache_read_pc (regcache);
3618 gdb_assert (is_executing (lp->ptid));
3620 /* Don't bother if there's a breakpoint at PC that we'd hit
3621 immediately, and we're not waiting for this LWP. */
3622 if (!ptid_match (lp->ptid, *wait_ptid_p))
3624 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3628 if (debug_linux_nat)
3629 fprintf_unfiltered (gdb_stdlog,
3630 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3631 target_pid_to_str (lp->ptid),
3632 paddress (gdbarch, pc),
3635 registers_changed ();
3636 if (linux_nat_prepare_to_resume != NULL)
3637 linux_nat_prepare_to_resume (lp);
3638 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3639 lp->step, GDB_SIGNAL_0);
3641 lp->stopped_by_watchpoint = 0;
3648 linux_nat_wait (struct target_ops *ops,
3649 ptid_t ptid, struct target_waitstatus *ourstatus,
3654 if (debug_linux_nat)
3656 char *options_string;
3658 options_string = target_options_to_string (target_options);
3659 fprintf_unfiltered (gdb_stdlog,
3660 "linux_nat_wait: [%s], [%s]\n",
3661 target_pid_to_str (ptid),
3663 xfree (options_string);
3666 /* Flush the async file first. */
3667 if (target_can_async_p ())
3668 async_file_flush ();
3670 /* Resume LWPs that are currently stopped without any pending status
3671 to report, but are resumed from the core's perspective. LWPs get
3672 in this state if we find them stopping at a time we're not
3673 interested in reporting the event (target_wait on a
3674 specific_process, for example, see linux_nat_wait_1), and
3675 meanwhile the event became uninteresting. Don't bother resuming
3676 LWPs we're not going to wait for if they'd stop immediately. */
3678 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3680 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3682 /* If we requested any event, and something came out, assume there
3683 may be more. If we requested a specific lwp or process, also
3684 assume there may be more. */
3685 if (target_can_async_p ()
3686 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3687 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3688 || !ptid_equal (ptid, minus_one_ptid)))
3691 /* Get ready for the next event. */
3692 if (target_can_async_p ())
3693 target_async (inferior_event_handler, 0);
3699 kill_callback (struct lwp_info *lp, void *data)
3701 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3704 kill (ptid_get_lwp (lp->ptid), SIGKILL);
3705 if (debug_linux_nat)
3706 fprintf_unfiltered (gdb_stdlog,
3707 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3708 target_pid_to_str (lp->ptid),
3709 errno ? safe_strerror (errno) : "OK");
3711 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3714 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3715 if (debug_linux_nat)
3716 fprintf_unfiltered (gdb_stdlog,
3717 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3718 target_pid_to_str (lp->ptid),
3719 errno ? safe_strerror (errno) : "OK");
3725 kill_wait_callback (struct lwp_info *lp, void *data)
3729 /* We must make sure that there are no pending events (delayed
3730 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3731 program doesn't interfere with any following debugging session. */
3733 /* For cloned processes we must check both with __WCLONE and
3734 without, since the exit status of a cloned process isn't reported
3740 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3741 if (pid != (pid_t) -1)
3743 if (debug_linux_nat)
3744 fprintf_unfiltered (gdb_stdlog,
3745 "KWC: wait %s received unknown.\n",
3746 target_pid_to_str (lp->ptid));
3747 /* The Linux kernel sometimes fails to kill a thread
3748 completely after PTRACE_KILL; that goes from the stop
3749 point in do_fork out to the one in
3750 get_signal_to_deliever and waits again. So kill it
3752 kill_callback (lp, NULL);
3755 while (pid == ptid_get_lwp (lp->ptid));
3757 gdb_assert (pid == -1 && errno == ECHILD);
3762 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3763 if (pid != (pid_t) -1)
3765 if (debug_linux_nat)
3766 fprintf_unfiltered (gdb_stdlog,
3767 "KWC: wait %s received unk.\n",
3768 target_pid_to_str (lp->ptid));
3769 /* See the call to kill_callback above. */
3770 kill_callback (lp, NULL);
3773 while (pid == ptid_get_lwp (lp->ptid));
3775 gdb_assert (pid == -1 && errno == ECHILD);
3780 linux_nat_kill (struct target_ops *ops)
3782 struct target_waitstatus last;
3786 /* If we're stopped while forking and we haven't followed yet,
3787 kill the other task. We need to do this first because the
3788 parent will be sleeping if this is a vfork. */
3790 get_last_target_status (&last_ptid, &last);
3792 if (last.kind == TARGET_WAITKIND_FORKED
3793 || last.kind == TARGET_WAITKIND_VFORKED)
3795 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3798 /* Let the arch-specific native code know this process is
3800 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3803 if (forks_exist_p ())
3804 linux_fork_killall ();
3807 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3809 /* Stop all threads before killing them, since ptrace requires
3810 that the thread is stopped to sucessfully PTRACE_KILL. */
3811 iterate_over_lwps (ptid, stop_callback, NULL);
3812 /* ... and wait until all of them have reported back that
3813 they're no longer running. */
3814 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3816 /* Kill all LWP's ... */
3817 iterate_over_lwps (ptid, kill_callback, NULL);
3819 /* ... and wait until we've flushed all events. */
3820 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3823 target_mourn_inferior ();
3827 linux_nat_mourn_inferior (struct target_ops *ops)
3829 int pid = ptid_get_pid (inferior_ptid);
3831 purge_lwp_list (pid);
3833 if (! forks_exist_p ())
3834 /* Normal case, no other forks available. */
3835 linux_ops->to_mourn_inferior (ops);
3837 /* Multi-fork case. The current inferior_ptid has exited, but
3838 there are other viable forks to debug. Delete the exiting
3839 one and context-switch to the first available. */
3840 linux_fork_mourn_inferior ();
3842 /* Let the arch-specific native code know this process is gone. */
3843 linux_nat_forget_process (pid);
3846 /* Convert a native/host siginfo object, into/from the siginfo in the
3847 layout of the inferiors' architecture. */
3850 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3854 if (linux_nat_siginfo_fixup != NULL)
3855 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3857 /* If there was no callback, or the callback didn't do anything,
3858 then just do a straight memcpy. */
3862 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3864 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3869 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3870 const char *annex, gdb_byte *readbuf,
3871 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
3875 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3877 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3878 gdb_assert (readbuf || writebuf);
3880 pid = ptid_get_lwp (inferior_ptid);
3882 pid = ptid_get_pid (inferior_ptid);
3884 if (offset > sizeof (siginfo))
3888 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3892 /* When GDB is built as a 64-bit application, ptrace writes into
3893 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3894 inferior with a 64-bit GDB should look the same as debugging it
3895 with a 32-bit GDB, we need to convert it. GDB core always sees
3896 the converted layout, so any read/write will have to be done
3898 siginfo_fixup (&siginfo, inf_siginfo, 0);
3900 if (offset + len > sizeof (siginfo))
3901 len = sizeof (siginfo) - offset;
3903 if (readbuf != NULL)
3904 memcpy (readbuf, inf_siginfo + offset, len);
3907 memcpy (inf_siginfo + offset, writebuf, len);
3909 /* Convert back to ptrace layout before flushing it out. */
3910 siginfo_fixup (&siginfo, inf_siginfo, 1);
3913 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3922 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3923 const char *annex, gdb_byte *readbuf,
3924 const gdb_byte *writebuf,
3925 ULONGEST offset, LONGEST len)
3927 struct cleanup *old_chain;
3930 if (object == TARGET_OBJECT_SIGNAL_INFO)
3931 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3934 /* The target is connected but no live inferior is selected. Pass
3935 this request down to a lower stratum (e.g., the executable
3937 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3940 old_chain = save_inferior_ptid ();
3942 if (ptid_lwp_p (inferior_ptid))
3943 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3945 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3948 do_cleanups (old_chain);
3953 linux_thread_alive (ptid_t ptid)
3957 gdb_assert (ptid_lwp_p (ptid));
3959 /* Send signal 0 instead of anything ptrace, because ptracing a
3960 running thread errors out claiming that the thread doesn't
3962 err = kill_lwp (ptid_get_lwp (ptid), 0);
3964 if (debug_linux_nat)
3965 fprintf_unfiltered (gdb_stdlog,
3966 "LLTA: KILL(SIG0) %s (%s)\n",
3967 target_pid_to_str (ptid),
3968 err ? safe_strerror (tmp_errno) : "OK");
3977 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3979 return linux_thread_alive (ptid);
3983 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3985 static char buf[64];
3987 if (ptid_lwp_p (ptid)
3988 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
3989 || num_lwps (ptid_get_pid (ptid)) > 1))
3991 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
3995 return normal_pid_to_str (ptid);
3999 linux_nat_thread_name (struct thread_info *thr)
4001 int pid = ptid_get_pid (thr->ptid);
4002 long lwp = ptid_get_lwp (thr->ptid);
4003 #define FORMAT "/proc/%d/task/%ld/comm"
4004 char buf[sizeof (FORMAT) + 30];
4006 char *result = NULL;
4008 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
4009 comm_file = gdb_fopen_cloexec (buf, "r");
4012 /* Not exported by the kernel, so we define it here. */
4014 static char line[COMM_LEN + 1];
4016 if (fgets (line, sizeof (line), comm_file))
4018 char *nl = strchr (line, '\n');
4035 /* Accepts an integer PID; Returns a string representing a file that
4036 can be opened to get the symbols for the child process. */
4039 linux_child_pid_to_exec_file (int pid)
4041 char *name1, *name2;
4043 name1 = xmalloc (PATH_MAX);
4044 name2 = xmalloc (PATH_MAX);
4045 make_cleanup (xfree, name1);
4046 make_cleanup (xfree, name2);
4047 memset (name2, 0, PATH_MAX);
4049 sprintf (name1, "/proc/%d/exe", pid);
4050 if (readlink (name1, name2, PATH_MAX - 1) > 0)
4056 /* Records the thread's register state for the corefile note
4060 linux_nat_collect_thread_registers (const struct regcache *regcache,
4061 ptid_t ptid, bfd *obfd,
4062 char *note_data, int *note_size,
4063 enum gdb_signal stop_signal)
4065 struct gdbarch *gdbarch = get_regcache_arch (regcache);
4066 const struct regset *regset;
4068 gdb_gregset_t gregs;
4069 gdb_fpregset_t fpregs;
4071 core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
4074 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
4076 != NULL && regset->collect_regset != NULL)
4077 regset->collect_regset (regset, regcache, -1, &gregs, sizeof (gregs));
4079 fill_gregset (regcache, &gregs, -1);
4081 note_data = (char *) elfcore_write_prstatus
4082 (obfd, note_data, note_size, ptid_get_lwp (ptid),
4083 gdb_signal_to_host (stop_signal), &gregs);
4086 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
4088 != NULL && regset->collect_regset != NULL)
4089 regset->collect_regset (regset, regcache, -1, &fpregs, sizeof (fpregs));
4091 fill_fpregset (regcache, &fpregs, -1);
4093 note_data = (char *) elfcore_write_prfpreg (obfd, note_data, note_size,
4094 &fpregs, sizeof (fpregs));
4099 /* Fills the "to_make_corefile_note" target vector. Builds the note
4100 section for a corefile, and returns it in a malloc buffer. */
4103 linux_nat_make_corefile_notes (bfd *obfd, int *note_size)
4105 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4106 converted to gdbarch_core_regset_sections, this function can go away. */
4107 return linux_make_corefile_notes (target_gdbarch (), obfd, note_size,
4108 linux_nat_collect_thread_registers);
4111 /* Implement the to_xfer_partial interface for memory reads using the /proc
4112 filesystem. Because we can use a single read() call for /proc, this
4113 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4114 but it doesn't support writes. */
4117 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4118 const char *annex, gdb_byte *readbuf,
4119 const gdb_byte *writebuf,
4120 ULONGEST offset, LONGEST len)
4126 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4129 /* Don't bother for one word. */
4130 if (len < 3 * sizeof (long))
4133 /* We could keep this file open and cache it - possibly one per
4134 thread. That requires some juggling, but is even faster. */
4135 sprintf (filename, "/proc/%d/mem", 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 sprintf (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);