1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2013 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "nat/linux-nat.h"
24 #include "nat/linux-waitpid.h"
27 #include "gdb_assert.h"
28 #ifdef HAVE_TKILL_SYSCALL
30 #include <sys/syscall.h>
32 #include <sys/ptrace.h>
33 #include "linux-nat.h"
34 #include "linux-ptrace.h"
35 #include "linux-procfs.h"
36 #include "linux-fork.h"
37 #include "gdbthread.h"
41 #include "inf-child.h"
42 #include "inf-ptrace.h"
44 #include <sys/procfs.h> /* for elf_gregset etc. */
45 #include "elf-bfd.h" /* for elfcore_write_* */
46 #include "gregset.h" /* for gregset */
47 #include "gdbcore.h" /* for get_exec_file */
48 #include <ctype.h> /* for isdigit */
49 #include "gdbthread.h" /* for struct thread_info etc. */
50 #include "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>
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, const 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))
1592 /* Put the signal number in ARGS so that inf_ptrace_detach will
1593 pass it along with PTRACE_DETACH. */
1595 sprintf (tem, "%d", (int) WSTOPSIG (status));
1597 if (debug_linux_nat)
1598 fprintf_unfiltered (gdb_stdlog,
1599 "LND: Sending signal %s to %s\n",
1601 target_pid_to_str (main_lwp->ptid));
1604 if (linux_nat_prepare_to_resume != NULL)
1605 linux_nat_prepare_to_resume (main_lwp);
1606 delete_lwp (main_lwp->ptid);
1608 if (forks_exist_p ())
1610 /* Multi-fork case. The current inferior_ptid is being detached
1611 from, but there are other viable forks to debug. Detach from
1612 the current fork, and context-switch to the first
1614 linux_fork_detach (args, from_tty);
1617 linux_ops->to_detach (ops, args, from_tty);
1623 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1627 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
1629 if (inf->vfork_child != NULL)
1631 if (debug_linux_nat)
1632 fprintf_unfiltered (gdb_stdlog,
1633 "RC: Not resuming %s (vfork parent)\n",
1634 target_pid_to_str (lp->ptid));
1636 else if (lp->status == 0
1637 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
1639 if (debug_linux_nat)
1640 fprintf_unfiltered (gdb_stdlog,
1641 "RC: Resuming sibling %s, %s, %s\n",
1642 target_pid_to_str (lp->ptid),
1643 (signo != GDB_SIGNAL_0
1644 ? strsignal (gdb_signal_to_host (signo))
1646 step ? "step" : "resume");
1648 if (linux_nat_prepare_to_resume != NULL)
1649 linux_nat_prepare_to_resume (lp);
1650 linux_ops->to_resume (linux_ops,
1651 pid_to_ptid (ptid_get_lwp (lp->ptid)),
1655 lp->stopped_by_watchpoint = 0;
1659 if (debug_linux_nat)
1660 fprintf_unfiltered (gdb_stdlog,
1661 "RC: Not resuming sibling %s (has pending)\n",
1662 target_pid_to_str (lp->ptid));
1667 if (debug_linux_nat)
1668 fprintf_unfiltered (gdb_stdlog,
1669 "RC: Not resuming sibling %s (not stopped)\n",
1670 target_pid_to_str (lp->ptid));
1674 /* Resume LWP, with the last stop signal, if it is in pass state. */
1677 linux_nat_resume_callback (struct lwp_info *lp, void *data)
1679 enum gdb_signal signo = GDB_SIGNAL_0;
1683 struct thread_info *thread;
1685 thread = find_thread_ptid (lp->ptid);
1688 if (signal_pass_state (thread->suspend.stop_signal))
1689 signo = thread->suspend.stop_signal;
1690 thread->suspend.stop_signal = GDB_SIGNAL_0;
1694 resume_lwp (lp, 0, signo);
1699 resume_clear_callback (struct lwp_info *lp, void *data)
1702 lp->last_resume_kind = resume_stop;
1707 resume_set_callback (struct lwp_info *lp, void *data)
1710 lp->last_resume_kind = resume_continue;
1715 linux_nat_resume (struct target_ops *ops,
1716 ptid_t ptid, int step, enum gdb_signal signo)
1718 struct lwp_info *lp;
1721 if (debug_linux_nat)
1722 fprintf_unfiltered (gdb_stdlog,
1723 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1724 step ? "step" : "resume",
1725 target_pid_to_str (ptid),
1726 (signo != GDB_SIGNAL_0
1727 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1728 target_pid_to_str (inferior_ptid));
1730 /* A specific PTID means `step only this process id'. */
1731 resume_many = (ptid_equal (minus_one_ptid, ptid)
1732 || ptid_is_pid (ptid));
1734 /* Mark the lwps we're resuming as resumed. */
1735 iterate_over_lwps (ptid, resume_set_callback, NULL);
1737 /* See if it's the current inferior that should be handled
1740 lp = find_lwp_pid (inferior_ptid);
1742 lp = find_lwp_pid (ptid);
1743 gdb_assert (lp != NULL);
1745 /* Remember if we're stepping. */
1747 lp->last_resume_kind = step ? resume_step : resume_continue;
1749 /* If we have a pending wait status for this thread, there is no
1750 point in resuming the process. But first make sure that
1751 linux_nat_wait won't preemptively handle the event - we
1752 should never take this short-circuit if we are going to
1753 leave LP running, since we have skipped resuming all the
1754 other threads. This bit of code needs to be synchronized
1755 with linux_nat_wait. */
1757 if (lp->status && WIFSTOPPED (lp->status))
1760 && WSTOPSIG (lp->status)
1761 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1763 if (debug_linux_nat)
1764 fprintf_unfiltered (gdb_stdlog,
1765 "LLR: Not short circuiting for ignored "
1766 "status 0x%x\n", lp->status);
1768 /* FIXME: What should we do if we are supposed to continue
1769 this thread with a signal? */
1770 gdb_assert (signo == GDB_SIGNAL_0);
1771 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1776 if (lp->status || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1778 /* FIXME: What should we do if we are supposed to continue
1779 this thread with a signal? */
1780 gdb_assert (signo == GDB_SIGNAL_0);
1782 if (debug_linux_nat)
1783 fprintf_unfiltered (gdb_stdlog,
1784 "LLR: Short circuiting for status 0x%x\n",
1787 if (target_can_async_p ())
1789 target_async (inferior_event_handler, 0);
1790 /* Tell the event loop we have something to process. */
1796 /* Mark LWP as not stopped to prevent it from being continued by
1797 linux_nat_resume_callback. */
1801 iterate_over_lwps (ptid, linux_nat_resume_callback, NULL);
1803 /* Convert to something the lower layer understands. */
1804 ptid = pid_to_ptid (ptid_get_lwp (lp->ptid));
1806 if (linux_nat_prepare_to_resume != NULL)
1807 linux_nat_prepare_to_resume (lp);
1808 linux_ops->to_resume (linux_ops, ptid, step, signo);
1809 lp->stopped_by_watchpoint = 0;
1811 if (debug_linux_nat)
1812 fprintf_unfiltered (gdb_stdlog,
1813 "LLR: %s %s, %s (resume event thread)\n",
1814 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1815 target_pid_to_str (ptid),
1816 (signo != GDB_SIGNAL_0
1817 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1819 if (target_can_async_p ())
1820 target_async (inferior_event_handler, 0);
1823 /* Send a signal to an LWP. */
1826 kill_lwp (int lwpid, int signo)
1828 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1829 fails, then we are not using nptl threads and we should be using kill. */
1831 #ifdef HAVE_TKILL_SYSCALL
1833 static int tkill_failed;
1840 ret = syscall (__NR_tkill, lwpid, signo);
1841 if (errno != ENOSYS)
1848 return kill (lwpid, signo);
1851 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1852 event, check if the core is interested in it: if not, ignore the
1853 event, and keep waiting; otherwise, we need to toggle the LWP's
1854 syscall entry/exit status, since the ptrace event itself doesn't
1855 indicate it, and report the trap to higher layers. */
1858 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1860 struct target_waitstatus *ourstatus = &lp->waitstatus;
1861 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1862 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1866 /* If we're stopping threads, there's a SIGSTOP pending, which
1867 makes it so that the LWP reports an immediate syscall return,
1868 followed by the SIGSTOP. Skip seeing that "return" using
1869 PTRACE_CONT directly, and let stop_wait_callback collect the
1870 SIGSTOP. Later when the thread is resumed, a new syscall
1871 entry event. If we didn't do this (and returned 0), we'd
1872 leave a syscall entry pending, and our caller, by using
1873 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1874 itself. Later, when the user re-resumes this LWP, we'd see
1875 another syscall entry event and we'd mistake it for a return.
1877 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1878 (leaving immediately with LWP->signalled set, without issuing
1879 a PTRACE_CONT), it would still be problematic to leave this
1880 syscall enter pending, as later when the thread is resumed,
1881 it would then see the same syscall exit mentioned above,
1882 followed by the delayed SIGSTOP, while the syscall didn't
1883 actually get to execute. It seems it would be even more
1884 confusing to the user. */
1886 if (debug_linux_nat)
1887 fprintf_unfiltered (gdb_stdlog,
1888 "LHST: ignoring syscall %d "
1889 "for LWP %ld (stopping threads), "
1890 "resuming with PTRACE_CONT for SIGSTOP\n",
1892 ptid_get_lwp (lp->ptid));
1894 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1895 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1899 if (catch_syscall_enabled ())
1901 /* Always update the entry/return state, even if this particular
1902 syscall isn't interesting to the core now. In async mode,
1903 the user could install a new catchpoint for this syscall
1904 between syscall enter/return, and we'll need to know to
1905 report a syscall return if that happens. */
1906 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1907 ? TARGET_WAITKIND_SYSCALL_RETURN
1908 : TARGET_WAITKIND_SYSCALL_ENTRY);
1910 if (catching_syscall_number (syscall_number))
1912 /* Alright, an event to report. */
1913 ourstatus->kind = lp->syscall_state;
1914 ourstatus->value.syscall_number = syscall_number;
1916 if (debug_linux_nat)
1917 fprintf_unfiltered (gdb_stdlog,
1918 "LHST: stopping for %s of syscall %d"
1921 == TARGET_WAITKIND_SYSCALL_ENTRY
1922 ? "entry" : "return",
1924 ptid_get_lwp (lp->ptid));
1928 if (debug_linux_nat)
1929 fprintf_unfiltered (gdb_stdlog,
1930 "LHST: ignoring %s of syscall %d "
1932 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1933 ? "entry" : "return",
1935 ptid_get_lwp (lp->ptid));
1939 /* If we had been syscall tracing, and hence used PT_SYSCALL
1940 before on this LWP, it could happen that the user removes all
1941 syscall catchpoints before we get to process this event.
1942 There are two noteworthy issues here:
1944 - When stopped at a syscall entry event, resuming with
1945 PT_STEP still resumes executing the syscall and reports a
1948 - Only PT_SYSCALL catches syscall enters. If we last
1949 single-stepped this thread, then this event can't be a
1950 syscall enter. If we last single-stepped this thread, this
1951 has to be a syscall exit.
1953 The points above mean that the next resume, be it PT_STEP or
1954 PT_CONTINUE, can not trigger a syscall trace event. */
1955 if (debug_linux_nat)
1956 fprintf_unfiltered (gdb_stdlog,
1957 "LHST: caught syscall event "
1958 "with no syscall catchpoints."
1959 " %d for LWP %ld, ignoring\n",
1961 ptid_get_lwp (lp->ptid));
1962 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1965 /* The core isn't interested in this event. For efficiency, avoid
1966 stopping all threads only to have the core resume them all again.
1967 Since we're not stopping threads, if we're still syscall tracing
1968 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1969 subsequent syscall. Simply resume using the inf-ptrace layer,
1970 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1972 /* Note that gdbarch_get_syscall_number may access registers, hence
1974 registers_changed ();
1975 if (linux_nat_prepare_to_resume != NULL)
1976 linux_nat_prepare_to_resume (lp);
1977 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
1978 lp->step, GDB_SIGNAL_0);
1982 /* Handle a GNU/Linux extended wait response. If we see a clone
1983 event, we need to add the new LWP to our list (and not report the
1984 trap to higher layers). This function returns non-zero if the
1985 event should be ignored and we should wait again. If STOPPING is
1986 true, the new LWP remains stopped, otherwise it is continued. */
1989 linux_handle_extended_wait (struct lwp_info *lp, int status,
1992 int pid = ptid_get_lwp (lp->ptid);
1993 struct target_waitstatus *ourstatus = &lp->waitstatus;
1994 int event = status >> 16;
1996 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1997 || event == PTRACE_EVENT_CLONE)
1999 unsigned long new_pid;
2002 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
2004 /* If we haven't already seen the new PID stop, wait for it now. */
2005 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
2007 /* The new child has a pending SIGSTOP. We can't affect it until it
2008 hits the SIGSTOP, but we're already attached. */
2009 ret = my_waitpid (new_pid, &status,
2010 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
2012 perror_with_name (_("waiting for new child"));
2013 else if (ret != new_pid)
2014 internal_error (__FILE__, __LINE__,
2015 _("wait returned unexpected PID %d"), ret);
2016 else if (!WIFSTOPPED (status))
2017 internal_error (__FILE__, __LINE__,
2018 _("wait returned unexpected status 0x%x"), status);
2021 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
2023 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
2025 /* The arch-specific native code may need to know about new
2026 forks even if those end up never mapped to an
2028 if (linux_nat_new_fork != NULL)
2029 linux_nat_new_fork (lp, new_pid);
2032 if (event == PTRACE_EVENT_FORK
2033 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
2035 /* Handle checkpointing by linux-fork.c here as a special
2036 case. We don't want the follow-fork-mode or 'catch fork'
2037 to interfere with this. */
2039 /* This won't actually modify the breakpoint list, but will
2040 physically remove the breakpoints from the child. */
2041 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
2043 /* Retain child fork in ptrace (stopped) state. */
2044 if (!find_fork_pid (new_pid))
2047 /* Report as spurious, so that infrun doesn't want to follow
2048 this fork. We're actually doing an infcall in
2050 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
2052 /* Report the stop to the core. */
2056 if (event == PTRACE_EVENT_FORK)
2057 ourstatus->kind = TARGET_WAITKIND_FORKED;
2058 else if (event == PTRACE_EVENT_VFORK)
2059 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2062 struct lwp_info *new_lp;
2064 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2066 if (debug_linux_nat)
2067 fprintf_unfiltered (gdb_stdlog,
2068 "LHEW: Got clone event "
2069 "from LWP %d, new child is LWP %ld\n",
2072 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
2074 new_lp->stopped = 1;
2076 if (WSTOPSIG (status) != SIGSTOP)
2078 /* This can happen if someone starts sending signals to
2079 the new thread before it gets a chance to run, which
2080 have a lower number than SIGSTOP (e.g. SIGUSR1).
2081 This is an unlikely case, and harder to handle for
2082 fork / vfork than for clone, so we do not try - but
2083 we handle it for clone events here. We'll send
2084 the other signal on to the thread below. */
2086 new_lp->signalled = 1;
2090 struct thread_info *tp;
2092 /* When we stop for an event in some other thread, and
2093 pull the thread list just as this thread has cloned,
2094 we'll have seen the new thread in the thread_db list
2095 before handling the CLONE event (glibc's
2096 pthread_create adds the new thread to the thread list
2097 before clone'ing, and has the kernel fill in the
2098 thread's tid on the clone call with
2099 CLONE_PARENT_SETTID). If that happened, and the core
2100 had requested the new thread to stop, we'll have
2101 killed it with SIGSTOP. But since SIGSTOP is not an
2102 RT signal, it can only be queued once. We need to be
2103 careful to not resume the LWP if we wanted it to
2104 stop. In that case, we'll leave the SIGSTOP pending.
2105 It will later be reported as GDB_SIGNAL_0. */
2106 tp = find_thread_ptid (new_lp->ptid);
2107 if (tp != NULL && tp->stop_requested)
2108 new_lp->last_resume_kind = resume_stop;
2115 /* Add the new thread to GDB's lists as soon as possible
2118 1) the frontend doesn't have to wait for a stop to
2121 2) we tag it with the correct running state. */
2123 /* If the thread_db layer is active, let it know about
2124 this new thread, and add it to GDB's list. */
2125 if (!thread_db_attach_lwp (new_lp->ptid))
2127 /* We're not using thread_db. Add it to GDB's
2129 target_post_attach (ptid_get_lwp (new_lp->ptid));
2130 add_thread (new_lp->ptid);
2135 set_running (new_lp->ptid, 1);
2136 set_executing (new_lp->ptid, 1);
2137 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2139 new_lp->last_resume_kind = resume_continue;
2145 /* We created NEW_LP so it cannot yet contain STATUS. */
2146 gdb_assert (new_lp->status == 0);
2148 /* Save the wait status to report later. */
2149 if (debug_linux_nat)
2150 fprintf_unfiltered (gdb_stdlog,
2151 "LHEW: waitpid of new LWP %ld, "
2152 "saving status %s\n",
2153 (long) ptid_get_lwp (new_lp->ptid),
2154 status_to_str (status));
2155 new_lp->status = status;
2158 /* Note the need to use the low target ops to resume, to
2159 handle resuming with PT_SYSCALL if we have syscall
2163 new_lp->resumed = 1;
2167 gdb_assert (new_lp->last_resume_kind == resume_continue);
2168 if (debug_linux_nat)
2169 fprintf_unfiltered (gdb_stdlog,
2170 "LHEW: resuming new LWP %ld\n",
2171 ptid_get_lwp (new_lp->ptid));
2172 if (linux_nat_prepare_to_resume != NULL)
2173 linux_nat_prepare_to_resume (new_lp);
2174 linux_ops->to_resume (linux_ops, pid_to_ptid (new_pid),
2176 new_lp->stopped = 0;
2180 if (debug_linux_nat)
2181 fprintf_unfiltered (gdb_stdlog,
2182 "LHEW: resuming parent LWP %d\n", pid);
2183 if (linux_nat_prepare_to_resume != NULL)
2184 linux_nat_prepare_to_resume (lp);
2185 linux_ops->to_resume (linux_ops,
2186 pid_to_ptid (ptid_get_lwp (lp->ptid)),
2195 if (event == PTRACE_EVENT_EXEC)
2197 if (debug_linux_nat)
2198 fprintf_unfiltered (gdb_stdlog,
2199 "LHEW: Got exec event from LWP %ld\n",
2200 ptid_get_lwp (lp->ptid));
2202 ourstatus->kind = TARGET_WAITKIND_EXECD;
2203 ourstatus->value.execd_pathname
2204 = xstrdup (linux_child_pid_to_exec_file (pid));
2209 if (event == PTRACE_EVENT_VFORK_DONE)
2211 if (current_inferior ()->waiting_for_vfork_done)
2213 if (debug_linux_nat)
2214 fprintf_unfiltered (gdb_stdlog,
2215 "LHEW: Got expected PTRACE_EVENT_"
2216 "VFORK_DONE from LWP %ld: stopping\n",
2217 ptid_get_lwp (lp->ptid));
2219 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2223 if (debug_linux_nat)
2224 fprintf_unfiltered (gdb_stdlog,
2225 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2226 "from LWP %ld: resuming\n",
2227 ptid_get_lwp (lp->ptid));
2228 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2232 internal_error (__FILE__, __LINE__,
2233 _("unknown ptrace event %d"), event);
2236 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2240 wait_lwp (struct lwp_info *lp)
2244 int thread_dead = 0;
2247 gdb_assert (!lp->stopped);
2248 gdb_assert (lp->status == 0);
2250 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2251 block_child_signals (&prev_mask);
2255 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2256 was right and we should just call sigsuspend. */
2258 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2259 if (pid == -1 && errno == ECHILD)
2260 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2261 if (pid == -1 && errno == ECHILD)
2263 /* The thread has previously exited. We need to delete it
2264 now because, for some vendor 2.4 kernels with NPTL
2265 support backported, there won't be an exit event unless
2266 it is the main thread. 2.6 kernels will report an exit
2267 event for each thread that exits, as expected. */
2269 if (debug_linux_nat)
2270 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2271 target_pid_to_str (lp->ptid));
2276 /* Bugs 10970, 12702.
2277 Thread group leader may have exited in which case we'll lock up in
2278 waitpid if there are other threads, even if they are all zombies too.
2279 Basically, we're not supposed to use waitpid this way.
2280 __WCLONE is not applicable for the leader so we can't use that.
2281 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2282 process; it gets ESRCH both for the zombie and for running processes.
2284 As a workaround, check if we're waiting for the thread group leader and
2285 if it's a zombie, and avoid calling waitpid if it is.
2287 This is racy, what if the tgl becomes a zombie right after we check?
2288 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2289 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2291 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2292 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2295 if (debug_linux_nat)
2296 fprintf_unfiltered (gdb_stdlog,
2297 "WL: Thread group leader %s vanished.\n",
2298 target_pid_to_str (lp->ptid));
2302 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2303 get invoked despite our caller had them intentionally blocked by
2304 block_child_signals. This is sensitive only to the loop of
2305 linux_nat_wait_1 and there if we get called my_waitpid gets called
2306 again before it gets to sigsuspend so we can safely let the handlers
2307 get executed here. */
2309 sigsuspend (&suspend_mask);
2312 restore_child_signals_mask (&prev_mask);
2316 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2318 if (debug_linux_nat)
2320 fprintf_unfiltered (gdb_stdlog,
2321 "WL: waitpid %s received %s\n",
2322 target_pid_to_str (lp->ptid),
2323 status_to_str (status));
2326 /* Check if the thread has exited. */
2327 if (WIFEXITED (status) || WIFSIGNALED (status))
2330 if (debug_linux_nat)
2331 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2332 target_pid_to_str (lp->ptid));
2342 gdb_assert (WIFSTOPPED (status));
2344 /* Handle GNU/Linux's syscall SIGTRAPs. */
2345 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2347 /* No longer need the sysgood bit. The ptrace event ends up
2348 recorded in lp->waitstatus if we care for it. We can carry
2349 on handling the event like a regular SIGTRAP from here
2351 status = W_STOPCODE (SIGTRAP);
2352 if (linux_handle_syscall_trap (lp, 1))
2353 return wait_lwp (lp);
2356 /* Handle GNU/Linux's extended waitstatus for trace events. */
2357 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2359 if (debug_linux_nat)
2360 fprintf_unfiltered (gdb_stdlog,
2361 "WL: Handling extended status 0x%06x\n",
2363 if (linux_handle_extended_wait (lp, status, 1))
2364 return wait_lwp (lp);
2370 /* Send a SIGSTOP to LP. */
2373 stop_callback (struct lwp_info *lp, void *data)
2375 if (!lp->stopped && !lp->signalled)
2379 if (debug_linux_nat)
2381 fprintf_unfiltered (gdb_stdlog,
2382 "SC: kill %s **<SIGSTOP>**\n",
2383 target_pid_to_str (lp->ptid));
2386 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2387 if (debug_linux_nat)
2389 fprintf_unfiltered (gdb_stdlog,
2390 "SC: lwp kill %d %s\n",
2392 errno ? safe_strerror (errno) : "ERRNO-OK");
2396 gdb_assert (lp->status == 0);
2402 /* Request a stop on LWP. */
2405 linux_stop_lwp (struct lwp_info *lwp)
2407 stop_callback (lwp, NULL);
2410 /* Return non-zero if LWP PID has a pending SIGINT. */
2413 linux_nat_has_pending_sigint (int pid)
2415 sigset_t pending, blocked, ignored;
2417 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2419 if (sigismember (&pending, SIGINT)
2420 && !sigismember (&ignored, SIGINT))
2426 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2429 set_ignore_sigint (struct lwp_info *lp, void *data)
2431 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2432 flag to consume the next one. */
2433 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2434 && WSTOPSIG (lp->status) == SIGINT)
2437 lp->ignore_sigint = 1;
2442 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2443 This function is called after we know the LWP has stopped; if the LWP
2444 stopped before the expected SIGINT was delivered, then it will never have
2445 arrived. Also, if the signal was delivered to a shared queue and consumed
2446 by a different thread, it will never be delivered to this LWP. */
2449 maybe_clear_ignore_sigint (struct lwp_info *lp)
2451 if (!lp->ignore_sigint)
2454 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2456 if (debug_linux_nat)
2457 fprintf_unfiltered (gdb_stdlog,
2458 "MCIS: Clearing bogus flag for %s\n",
2459 target_pid_to_str (lp->ptid));
2460 lp->ignore_sigint = 0;
2464 /* Fetch the possible triggered data watchpoint info and store it in
2467 On some archs, like x86, that use debug registers to set
2468 watchpoints, it's possible that the way to know which watched
2469 address trapped, is to check the register that is used to select
2470 which address to watch. Problem is, between setting the watchpoint
2471 and reading back which data address trapped, the user may change
2472 the set of watchpoints, and, as a consequence, GDB changes the
2473 debug registers in the inferior. To avoid reading back a stale
2474 stopped-data-address when that happens, we cache in LP the fact
2475 that a watchpoint trapped, and the corresponding data address, as
2476 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2477 registers meanwhile, we have the cached data we can rely on. */
2480 save_sigtrap (struct lwp_info *lp)
2482 struct cleanup *old_chain;
2484 if (linux_ops->to_stopped_by_watchpoint == NULL)
2486 lp->stopped_by_watchpoint = 0;
2490 old_chain = save_inferior_ptid ();
2491 inferior_ptid = lp->ptid;
2493 lp->stopped_by_watchpoint = linux_ops->to_stopped_by_watchpoint ();
2495 if (lp->stopped_by_watchpoint)
2497 if (linux_ops->to_stopped_data_address != NULL)
2498 lp->stopped_data_address_p =
2499 linux_ops->to_stopped_data_address (¤t_target,
2500 &lp->stopped_data_address);
2502 lp->stopped_data_address_p = 0;
2505 do_cleanups (old_chain);
2508 /* See save_sigtrap. */
2511 linux_nat_stopped_by_watchpoint (void)
2513 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2515 gdb_assert (lp != NULL);
2517 return lp->stopped_by_watchpoint;
2521 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2523 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2525 gdb_assert (lp != NULL);
2527 *addr_p = lp->stopped_data_address;
2529 return lp->stopped_data_address_p;
2532 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2535 sigtrap_is_event (int status)
2537 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2540 /* SIGTRAP-like events recognizer. */
2542 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
2544 /* Check for SIGTRAP-like events in LP. */
2547 linux_nat_lp_status_is_event (struct lwp_info *lp)
2549 /* We check for lp->waitstatus in addition to lp->status, because we can
2550 have pending process exits recorded in lp->status
2551 and W_EXITCODE(0,0) == 0. We should probably have an additional
2552 lp->status_p flag. */
2554 return (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE
2555 && linux_nat_status_is_event (lp->status));
2558 /* Set alternative SIGTRAP-like events recognizer. If
2559 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2563 linux_nat_set_status_is_event (struct target_ops *t,
2564 int (*status_is_event) (int status))
2566 linux_nat_status_is_event = status_is_event;
2569 /* Wait until LP is stopped. */
2572 stop_wait_callback (struct lwp_info *lp, void *data)
2574 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2576 /* If this is a vfork parent, bail out, it is not going to report
2577 any SIGSTOP until the vfork is done with. */
2578 if (inf->vfork_child != NULL)
2585 status = wait_lwp (lp);
2589 if (lp->ignore_sigint && WIFSTOPPED (status)
2590 && WSTOPSIG (status) == SIGINT)
2592 lp->ignore_sigint = 0;
2595 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2596 if (debug_linux_nat)
2597 fprintf_unfiltered (gdb_stdlog,
2598 "PTRACE_CONT %s, 0, 0 (%s) "
2599 "(discarding SIGINT)\n",
2600 target_pid_to_str (lp->ptid),
2601 errno ? safe_strerror (errno) : "OK");
2603 return stop_wait_callback (lp, NULL);
2606 maybe_clear_ignore_sigint (lp);
2608 if (WSTOPSIG (status) != SIGSTOP)
2610 /* The thread was stopped with a signal other than SIGSTOP. */
2614 if (debug_linux_nat)
2615 fprintf_unfiltered (gdb_stdlog,
2616 "SWC: Pending event %s in %s\n",
2617 status_to_str ((int) status),
2618 target_pid_to_str (lp->ptid));
2620 /* Save the sigtrap event. */
2621 lp->status = status;
2622 gdb_assert (!lp->stopped);
2623 gdb_assert (lp->signalled);
2628 /* We caught the SIGSTOP that we intended to catch, so
2629 there's no SIGSTOP pending. */
2631 if (debug_linux_nat)
2632 fprintf_unfiltered (gdb_stdlog,
2633 "SWC: Delayed SIGSTOP caught for %s.\n",
2634 target_pid_to_str (lp->ptid));
2638 /* Reset SIGNALLED only after the stop_wait_callback call
2639 above as it does gdb_assert on SIGNALLED. */
2647 /* Return non-zero if LP has a wait status pending. */
2650 status_callback (struct lwp_info *lp, void *data)
2652 /* Only report a pending wait status if we pretend that this has
2653 indeed been resumed. */
2657 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2659 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2660 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2661 0', so a clean process exit can not be stored pending in
2662 lp->status, it is indistinguishable from
2663 no-pending-status. */
2667 if (lp->status != 0)
2673 /* Return non-zero if LP isn't stopped. */
2676 running_callback (struct lwp_info *lp, void *data)
2678 return (!lp->stopped
2679 || ((lp->status != 0
2680 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2684 /* Count the LWP's that have had events. */
2687 count_events_callback (struct lwp_info *lp, void *data)
2691 gdb_assert (count != NULL);
2693 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2694 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2700 /* Select the LWP (if any) that is currently being single-stepped. */
2703 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2705 if (lp->last_resume_kind == resume_step
2712 /* Select the Nth LWP that has had a SIGTRAP event. */
2715 select_event_lwp_callback (struct lwp_info *lp, void *data)
2717 int *selector = data;
2719 gdb_assert (selector != NULL);
2721 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2722 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2723 if ((*selector)-- == 0)
2730 cancel_breakpoint (struct lwp_info *lp)
2732 /* Arrange for a breakpoint to be hit again later. We don't keep
2733 the SIGTRAP status and don't forward the SIGTRAP signal to the
2734 LWP. We will handle the current event, eventually we will resume
2735 this LWP, and this breakpoint will trap again.
2737 If we do not do this, then we run the risk that the user will
2738 delete or disable the breakpoint, but the LWP will have already
2741 struct regcache *regcache = get_thread_regcache (lp->ptid);
2742 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2745 pc = regcache_read_pc (regcache) - gdbarch_decr_pc_after_break (gdbarch);
2746 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2748 if (debug_linux_nat)
2749 fprintf_unfiltered (gdb_stdlog,
2750 "CB: Push back breakpoint for %s\n",
2751 target_pid_to_str (lp->ptid));
2753 /* Back up the PC if necessary. */
2754 if (gdbarch_decr_pc_after_break (gdbarch))
2755 regcache_write_pc (regcache, pc);
2763 cancel_breakpoints_callback (struct lwp_info *lp, void *data)
2765 struct lwp_info *event_lp = data;
2767 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2771 /* If a LWP other than the LWP that we're reporting an event for has
2772 hit a GDB breakpoint (as opposed to some random trap signal),
2773 then just arrange for it to hit it again later. We don't keep
2774 the SIGTRAP status and don't forward the SIGTRAP signal to the
2775 LWP. We will handle the current event, eventually we will resume
2776 all LWPs, and this one will get its breakpoint trap again.
2778 If we do not do this, then we run the risk that the user will
2779 delete or disable the breakpoint, but the LWP will have already
2782 if (linux_nat_lp_status_is_event (lp)
2783 && cancel_breakpoint (lp))
2784 /* Throw away the SIGTRAP. */
2790 /* Select one LWP out of those that have events pending. */
2793 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2796 int random_selector;
2797 struct lwp_info *event_lp;
2799 /* Record the wait status for the original LWP. */
2800 (*orig_lp)->status = *status;
2802 /* Give preference to any LWP that is being single-stepped. */
2803 event_lp = iterate_over_lwps (filter,
2804 select_singlestep_lwp_callback, NULL);
2805 if (event_lp != NULL)
2807 if (debug_linux_nat)
2808 fprintf_unfiltered (gdb_stdlog,
2809 "SEL: Select single-step %s\n",
2810 target_pid_to_str (event_lp->ptid));
2814 /* No single-stepping LWP. Select one at random, out of those
2815 which have had SIGTRAP events. */
2817 /* First see how many SIGTRAP events we have. */
2818 iterate_over_lwps (filter, count_events_callback, &num_events);
2820 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2821 random_selector = (int)
2822 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2824 if (debug_linux_nat && num_events > 1)
2825 fprintf_unfiltered (gdb_stdlog,
2826 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2827 num_events, random_selector);
2829 event_lp = iterate_over_lwps (filter,
2830 select_event_lwp_callback,
2834 if (event_lp != NULL)
2836 /* Switch the event LWP. */
2837 *orig_lp = event_lp;
2838 *status = event_lp->status;
2841 /* Flush the wait status for the event LWP. */
2842 (*orig_lp)->status = 0;
2845 /* Return non-zero if LP has been resumed. */
2848 resumed_callback (struct lwp_info *lp, void *data)
2853 /* Stop an active thread, verify it still exists, then resume it. If
2854 the thread ends up with a pending status, then it is not resumed,
2855 and *DATA (really a pointer to int), is set. */
2858 stop_and_resume_callback (struct lwp_info *lp, void *data)
2860 int *new_pending_p = data;
2864 ptid_t ptid = lp->ptid;
2866 stop_callback (lp, NULL);
2867 stop_wait_callback (lp, NULL);
2869 /* Resume if the lwp still exists, and the core wanted it
2871 lp = find_lwp_pid (ptid);
2874 if (lp->last_resume_kind == resume_stop
2877 /* The core wanted the LWP to stop. Even if it stopped
2878 cleanly (with SIGSTOP), leave the event pending. */
2879 if (debug_linux_nat)
2880 fprintf_unfiltered (gdb_stdlog,
2881 "SARC: core wanted LWP %ld stopped "
2882 "(leaving SIGSTOP pending)\n",
2883 ptid_get_lwp (lp->ptid));
2884 lp->status = W_STOPCODE (SIGSTOP);
2887 if (lp->status == 0)
2889 if (debug_linux_nat)
2890 fprintf_unfiltered (gdb_stdlog,
2891 "SARC: re-resuming LWP %ld\n",
2892 ptid_get_lwp (lp->ptid));
2893 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2897 if (debug_linux_nat)
2898 fprintf_unfiltered (gdb_stdlog,
2899 "SARC: not re-resuming LWP %ld "
2901 ptid_get_lwp (lp->ptid));
2910 /* Check if we should go on and pass this event to common code.
2911 Return the affected lwp if we are, or NULL otherwise. If we stop
2912 all lwps temporarily, we may end up with new pending events in some
2913 other lwp. In that case set *NEW_PENDING_P to true. */
2915 static struct lwp_info *
2916 linux_nat_filter_event (int lwpid, int status, int *new_pending_p)
2918 struct lwp_info *lp;
2922 lp = find_lwp_pid (pid_to_ptid (lwpid));
2924 /* Check for stop events reported by a process we didn't already
2925 know about - anything not already in our LWP list.
2927 If we're expecting to receive stopped processes after
2928 fork, vfork, and clone events, then we'll just add the
2929 new one to our list and go back to waiting for the event
2930 to be reported - the stopped process might be returned
2931 from waitpid before or after the event is.
2933 But note the case of a non-leader thread exec'ing after the
2934 leader having exited, and gone from our lists. The non-leader
2935 thread changes its tid to the tgid. */
2937 if (WIFSTOPPED (status) && lp == NULL
2938 && (WSTOPSIG (status) == SIGTRAP && status >> 16 == PTRACE_EVENT_EXEC))
2940 /* A multi-thread exec after we had seen the leader exiting. */
2941 if (debug_linux_nat)
2942 fprintf_unfiltered (gdb_stdlog,
2943 "LLW: Re-adding thread group leader LWP %d.\n",
2946 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2949 add_thread (lp->ptid);
2952 if (WIFSTOPPED (status) && !lp)
2954 add_to_pid_list (&stopped_pids, lwpid, status);
2958 /* Make sure we don't report an event for the exit of an LWP not in
2959 our list, i.e. not part of the current process. This can happen
2960 if we detach from a program we originally forked and then it
2962 if (!WIFSTOPPED (status) && !lp)
2965 /* Handle GNU/Linux's syscall SIGTRAPs. */
2966 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2968 /* No longer need the sysgood bit. The ptrace event ends up
2969 recorded in lp->waitstatus if we care for it. We can carry
2970 on handling the event like a regular SIGTRAP from here
2972 status = W_STOPCODE (SIGTRAP);
2973 if (linux_handle_syscall_trap (lp, 0))
2977 /* Handle GNU/Linux's extended waitstatus for trace events. */
2978 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2980 if (debug_linux_nat)
2981 fprintf_unfiltered (gdb_stdlog,
2982 "LLW: Handling extended status 0x%06x\n",
2984 if (linux_handle_extended_wait (lp, status, 0))
2988 if (linux_nat_status_is_event (status))
2991 /* Check if the thread has exited. */
2992 if ((WIFEXITED (status) || WIFSIGNALED (status))
2993 && num_lwps (ptid_get_pid (lp->ptid)) > 1)
2995 /* If this is the main thread, we must stop all threads and verify
2996 if they are still alive. This is because in the nptl thread model
2997 on Linux 2.4, there is no signal issued for exiting LWPs
2998 other than the main thread. We only get the main thread exit
2999 signal once all child threads have already exited. If we
3000 stop all the threads and use the stop_wait_callback to check
3001 if they have exited we can determine whether this signal
3002 should be ignored or whether it means the end of the debugged
3003 application, regardless of which threading model is being
3005 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
3008 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3009 stop_and_resume_callback, new_pending_p);
3012 if (debug_linux_nat)
3013 fprintf_unfiltered (gdb_stdlog,
3014 "LLW: %s exited.\n",
3015 target_pid_to_str (lp->ptid));
3017 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3019 /* If there is at least one more LWP, then the exit signal
3020 was not the end of the debugged application and should be
3027 /* Check if the current LWP has previously exited. In the nptl
3028 thread model, LWPs other than the main thread do not issue
3029 signals when they exit so we must check whenever the thread has
3030 stopped. A similar check is made in stop_wait_callback(). */
3031 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3033 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3035 if (debug_linux_nat)
3036 fprintf_unfiltered (gdb_stdlog,
3037 "LLW: %s exited.\n",
3038 target_pid_to_str (lp->ptid));
3042 /* Make sure there is at least one thread running. */
3043 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3045 /* Discard the event. */
3049 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3050 an attempt to stop an LWP. */
3052 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3054 if (debug_linux_nat)
3055 fprintf_unfiltered (gdb_stdlog,
3056 "LLW: Delayed SIGSTOP caught for %s.\n",
3057 target_pid_to_str (lp->ptid));
3061 if (lp->last_resume_kind != resume_stop)
3063 /* This is a delayed SIGSTOP. */
3065 registers_changed ();
3067 if (linux_nat_prepare_to_resume != NULL)
3068 linux_nat_prepare_to_resume (lp);
3069 linux_ops->to_resume (linux_ops,
3070 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3071 lp->step, GDB_SIGNAL_0);
3072 if (debug_linux_nat)
3073 fprintf_unfiltered (gdb_stdlog,
3074 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3076 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3077 target_pid_to_str (lp->ptid));
3080 gdb_assert (lp->resumed);
3082 /* Discard the event. */
3087 /* Make sure we don't report a SIGINT that we have already displayed
3088 for another thread. */
3089 if (lp->ignore_sigint
3090 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3092 if (debug_linux_nat)
3093 fprintf_unfiltered (gdb_stdlog,
3094 "LLW: Delayed SIGINT caught for %s.\n",
3095 target_pid_to_str (lp->ptid));
3097 /* This is a delayed SIGINT. */
3098 lp->ignore_sigint = 0;
3100 registers_changed ();
3101 if (linux_nat_prepare_to_resume != NULL)
3102 linux_nat_prepare_to_resume (lp);
3103 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3104 lp->step, GDB_SIGNAL_0);
3105 if (debug_linux_nat)
3106 fprintf_unfiltered (gdb_stdlog,
3107 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3109 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3110 target_pid_to_str (lp->ptid));
3113 gdb_assert (lp->resumed);
3115 /* Discard the event. */
3119 /* An interesting event. */
3121 lp->status = status;
3125 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3126 their exits until all other threads in the group have exited. */
3129 check_zombie_leaders (void)
3131 struct inferior *inf;
3135 struct lwp_info *leader_lp;
3140 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3141 if (leader_lp != NULL
3142 /* Check if there are other threads in the group, as we may
3143 have raced with the inferior simply exiting. */
3144 && num_lwps (inf->pid) > 1
3145 && linux_proc_pid_is_zombie (inf->pid))
3147 if (debug_linux_nat)
3148 fprintf_unfiltered (gdb_stdlog,
3149 "CZL: Thread group leader %d zombie "
3150 "(it exited, or another thread execd).\n",
3153 /* A leader zombie can mean one of two things:
3155 - It exited, and there's an exit status pending
3156 available, or only the leader exited (not the whole
3157 program). In the latter case, we can't waitpid the
3158 leader's exit status until all other threads are gone.
3160 - There are 3 or more threads in the group, and a thread
3161 other than the leader exec'd. On an exec, the Linux
3162 kernel destroys all other threads (except the execing
3163 one) in the thread group, and resets the execing thread's
3164 tid to the tgid. No exit notification is sent for the
3165 execing thread -- from the ptracer's perspective, it
3166 appears as though the execing thread just vanishes.
3167 Until we reap all other threads except the leader and the
3168 execing thread, the leader will be zombie, and the
3169 execing thread will be in `D (disc sleep)'. As soon as
3170 all other threads are reaped, the execing thread changes
3171 it's tid to the tgid, and the previous (zombie) leader
3172 vanishes, giving place to the "new" leader. We could try
3173 distinguishing the exit and exec cases, by waiting once
3174 more, and seeing if something comes out, but it doesn't
3175 sound useful. The previous leader _does_ go away, and
3176 we'll re-add the new one once we see the exec event
3177 (which is just the same as what would happen if the
3178 previous leader did exit voluntarily before some other
3181 if (debug_linux_nat)
3182 fprintf_unfiltered (gdb_stdlog,
3183 "CZL: Thread group leader %d vanished.\n",
3185 exit_lwp (leader_lp);
3191 linux_nat_wait_1 (struct target_ops *ops,
3192 ptid_t ptid, struct target_waitstatus *ourstatus,
3195 static sigset_t prev_mask;
3196 enum resume_kind last_resume_kind;
3197 struct lwp_info *lp;
3200 if (debug_linux_nat)
3201 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3203 /* The first time we get here after starting a new inferior, we may
3204 not have added it to the LWP list yet - this is the earliest
3205 moment at which we know its PID. */
3206 if (ptid_is_pid (inferior_ptid))
3208 /* Upgrade the main thread's ptid. */
3209 thread_change_ptid (inferior_ptid,
3210 ptid_build (ptid_get_pid (inferior_ptid),
3211 ptid_get_pid (inferior_ptid), 0));
3213 lp = add_initial_lwp (inferior_ptid);
3217 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3218 block_child_signals (&prev_mask);
3224 /* First check if there is a LWP with a wait status pending. */
3225 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3227 /* Any LWP in the PTID group that's been resumed will do. */
3228 lp = iterate_over_lwps (ptid, status_callback, NULL);
3231 if (debug_linux_nat && lp->status)
3232 fprintf_unfiltered (gdb_stdlog,
3233 "LLW: Using pending wait status %s for %s.\n",
3234 status_to_str (lp->status),
3235 target_pid_to_str (lp->ptid));
3238 else if (ptid_lwp_p (ptid))
3240 if (debug_linux_nat)
3241 fprintf_unfiltered (gdb_stdlog,
3242 "LLW: Waiting for specific LWP %s.\n",
3243 target_pid_to_str (ptid));
3245 /* We have a specific LWP to check. */
3246 lp = find_lwp_pid (ptid);
3249 if (debug_linux_nat && lp->status)
3250 fprintf_unfiltered (gdb_stdlog,
3251 "LLW: Using pending wait status %s for %s.\n",
3252 status_to_str (lp->status),
3253 target_pid_to_str (lp->ptid));
3255 /* We check for lp->waitstatus in addition to lp->status,
3256 because we can have pending process exits recorded in
3257 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3258 an additional lp->status_p flag. */
3259 if (lp->status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3263 if (!target_can_async_p ())
3265 /* Causes SIGINT to be passed on to the attached process. */
3269 /* But if we don't find a pending event, we'll have to wait. */
3275 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3278 - If the thread group leader exits while other threads in the
3279 thread group still exist, waitpid(TGID, ...) hangs. That
3280 waitpid won't return an exit status until the other threads
3281 in the group are reapped.
3283 - When a non-leader thread execs, that thread just vanishes
3284 without reporting an exit (so we'd hang if we waited for it
3285 explicitly in that case). The exec event is reported to
3289 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3290 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3291 lwpid = my_waitpid (-1, &status, WNOHANG);
3293 if (debug_linux_nat)
3294 fprintf_unfiltered (gdb_stdlog,
3295 "LNW: waitpid(-1, ...) returned %d, %s\n",
3296 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3300 /* If this is true, then we paused LWPs momentarily, and may
3301 now have pending events to handle. */
3304 if (debug_linux_nat)
3306 fprintf_unfiltered (gdb_stdlog,
3307 "LLW: waitpid %ld received %s\n",
3308 (long) lwpid, status_to_str (status));
3311 lp = linux_nat_filter_event (lwpid, status, &new_pending);
3313 /* STATUS is now no longer valid, use LP->STATUS instead. */
3316 if (lp && !ptid_match (lp->ptid, ptid))
3318 gdb_assert (lp->resumed);
3320 if (debug_linux_nat)
3322 "LWP %ld got an event %06x, leaving pending.\n",
3323 ptid_get_lwp (lp->ptid), lp->status);
3325 if (WIFSTOPPED (lp->status))
3327 if (WSTOPSIG (lp->status) != SIGSTOP)
3329 /* Cancel breakpoint hits. The breakpoint may
3330 be removed before we fetch events from this
3331 process to report to the core. It is best
3332 not to assume the moribund breakpoints
3333 heuristic always handles these cases --- it
3334 could be too many events go through to the
3335 core before this one is handled. All-stop
3336 always cancels breakpoint hits in all
3339 && linux_nat_lp_status_is_event (lp)
3340 && cancel_breakpoint (lp))
3342 /* Throw away the SIGTRAP. */
3345 if (debug_linux_nat)
3347 "LLW: LWP %ld hit a breakpoint while"
3348 " waiting for another process;"
3350 ptid_get_lwp (lp->ptid));
3360 else if (WIFEXITED (lp->status) || WIFSIGNALED (lp->status))
3362 if (debug_linux_nat)
3364 "Process %ld exited while stopping LWPs\n",
3365 ptid_get_lwp (lp->ptid));
3367 /* This was the last lwp in the process. Since
3368 events are serialized to GDB core, and we can't
3369 report this one right now, but GDB core and the
3370 other target layers will want to be notified
3371 about the exit code/signal, leave the status
3372 pending for the next time we're able to report
3375 /* Prevent trying to stop this thread again. We'll
3376 never try to resume it because it has a pending
3380 /* Dead LWP's aren't expected to reported a pending
3384 /* Store the pending event in the waitstatus as
3385 well, because W_EXITCODE(0,0) == 0. */
3386 store_waitstatus (&lp->waitstatus, lp->status);
3395 /* Some LWP now has a pending event. Go all the way
3396 back to check it. */
3402 /* We got an event to report to the core. */
3406 /* Retry until nothing comes out of waitpid. A single
3407 SIGCHLD can indicate more than one child stopped. */
3411 /* Check for zombie thread group leaders. Those can't be reaped
3412 until all other threads in the thread group are. */
3413 check_zombie_leaders ();
3415 /* If there are no resumed children left, bail. We'd be stuck
3416 forever in the sigsuspend call below otherwise. */
3417 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3419 if (debug_linux_nat)
3420 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3422 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3424 if (!target_can_async_p ())
3425 clear_sigint_trap ();
3427 restore_child_signals_mask (&prev_mask);
3428 return minus_one_ptid;
3431 /* No interesting event to report to the core. */
3433 if (target_options & TARGET_WNOHANG)
3435 if (debug_linux_nat)
3436 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3438 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3439 restore_child_signals_mask (&prev_mask);
3440 return minus_one_ptid;
3443 /* We shouldn't end up here unless we want to try again. */
3444 gdb_assert (lp == NULL);
3446 /* Block until we get an event reported with SIGCHLD. */
3447 sigsuspend (&suspend_mask);
3450 if (!target_can_async_p ())
3451 clear_sigint_trap ();
3455 status = lp->status;
3458 /* Don't report signals that GDB isn't interested in, such as
3459 signals that are neither printed nor stopped upon. Stopping all
3460 threads can be a bit time-consuming so if we want decent
3461 performance with heavily multi-threaded programs, especially when
3462 they're using a high frequency timer, we'd better avoid it if we
3465 if (WIFSTOPPED (status))
3467 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3469 /* When using hardware single-step, we need to report every signal.
3470 Otherwise, signals in pass_mask may be short-circuited. */
3472 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status)))
3474 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3475 here? It is not clear we should. GDB may not expect
3476 other threads to run. On the other hand, not resuming
3477 newly attached threads may cause an unwanted delay in
3478 getting them running. */
3479 registers_changed ();
3480 if (linux_nat_prepare_to_resume != NULL)
3481 linux_nat_prepare_to_resume (lp);
3482 linux_ops->to_resume (linux_ops,
3483 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3485 if (debug_linux_nat)
3486 fprintf_unfiltered (gdb_stdlog,
3487 "LLW: %s %s, %s (preempt 'handle')\n",
3489 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3490 target_pid_to_str (lp->ptid),
3491 (signo != GDB_SIGNAL_0
3492 ? strsignal (gdb_signal_to_host (signo))
3500 /* Only do the below in all-stop, as we currently use SIGINT
3501 to implement target_stop (see linux_nat_stop) in
3503 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3505 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3506 forwarded to the entire process group, that is, all LWPs
3507 will receive it - unless they're using CLONE_THREAD to
3508 share signals. Since we only want to report it once, we
3509 mark it as ignored for all LWPs except this one. */
3510 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)),
3511 set_ignore_sigint, NULL);
3512 lp->ignore_sigint = 0;
3515 maybe_clear_ignore_sigint (lp);
3519 /* This LWP is stopped now. */
3522 if (debug_linux_nat)
3523 fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
3524 status_to_str (status), target_pid_to_str (lp->ptid));
3528 /* Now stop all other LWP's ... */
3529 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3531 /* ... and wait until all of them have reported back that
3532 they're no longer running. */
3533 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3535 /* If we're not waiting for a specific LWP, choose an event LWP
3536 from among those that have had events. Giving equal priority
3537 to all LWPs that have had events helps prevent
3539 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3540 select_event_lwp (ptid, &lp, &status);
3542 /* Now that we've selected our final event LWP, cancel any
3543 breakpoints in other LWPs that have hit a GDB breakpoint.
3544 See the comment in cancel_breakpoints_callback to find out
3546 iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp);
3548 /* We'll need this to determine whether to report a SIGSTOP as
3549 TARGET_WAITKIND_0. Need to take a copy because
3550 resume_clear_callback clears it. */
3551 last_resume_kind = lp->last_resume_kind;
3553 /* In all-stop, from the core's perspective, all LWPs are now
3554 stopped until a new resume action is sent over. */
3555 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3560 last_resume_kind = lp->last_resume_kind;
3561 resume_clear_callback (lp, NULL);
3564 if (linux_nat_status_is_event (status))
3566 if (debug_linux_nat)
3567 fprintf_unfiltered (gdb_stdlog,
3568 "LLW: trap ptid is %s.\n",
3569 target_pid_to_str (lp->ptid));
3572 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3574 *ourstatus = lp->waitstatus;
3575 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3578 store_waitstatus (ourstatus, status);
3580 if (debug_linux_nat)
3581 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3583 restore_child_signals_mask (&prev_mask);
3585 if (last_resume_kind == resume_stop
3586 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3587 && WSTOPSIG (status) == SIGSTOP)
3589 /* A thread that has been requested to stop by GDB with
3590 target_stop, and it stopped cleanly, so report as SIG0. The
3591 use of SIGSTOP is an implementation detail. */
3592 ourstatus->value.sig = GDB_SIGNAL_0;
3595 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3596 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3599 lp->core = linux_common_core_of_thread (lp->ptid);
3604 /* Resume LWPs that are currently stopped without any pending status
3605 to report, but are resumed from the core's perspective. */
3608 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3610 ptid_t *wait_ptid_p = data;
3615 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3617 struct regcache *regcache = get_thread_regcache (lp->ptid);
3618 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3619 CORE_ADDR pc = regcache_read_pc (regcache);
3621 gdb_assert (is_executing (lp->ptid));
3623 /* Don't bother if there's a breakpoint at PC that we'd hit
3624 immediately, and we're not waiting for this LWP. */
3625 if (!ptid_match (lp->ptid, *wait_ptid_p))
3627 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3631 if (debug_linux_nat)
3632 fprintf_unfiltered (gdb_stdlog,
3633 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3634 target_pid_to_str (lp->ptid),
3635 paddress (gdbarch, pc),
3638 registers_changed ();
3639 if (linux_nat_prepare_to_resume != NULL)
3640 linux_nat_prepare_to_resume (lp);
3641 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3642 lp->step, GDB_SIGNAL_0);
3644 lp->stopped_by_watchpoint = 0;
3651 linux_nat_wait (struct target_ops *ops,
3652 ptid_t ptid, struct target_waitstatus *ourstatus,
3657 if (debug_linux_nat)
3659 char *options_string;
3661 options_string = target_options_to_string (target_options);
3662 fprintf_unfiltered (gdb_stdlog,
3663 "linux_nat_wait: [%s], [%s]\n",
3664 target_pid_to_str (ptid),
3666 xfree (options_string);
3669 /* Flush the async file first. */
3670 if (target_can_async_p ())
3671 async_file_flush ();
3673 /* Resume LWPs that are currently stopped without any pending status
3674 to report, but are resumed from the core's perspective. LWPs get
3675 in this state if we find them stopping at a time we're not
3676 interested in reporting the event (target_wait on a
3677 specific_process, for example, see linux_nat_wait_1), and
3678 meanwhile the event became uninteresting. Don't bother resuming
3679 LWPs we're not going to wait for if they'd stop immediately. */
3681 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3683 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3685 /* If we requested any event, and something came out, assume there
3686 may be more. If we requested a specific lwp or process, also
3687 assume there may be more. */
3688 if (target_can_async_p ()
3689 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3690 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3691 || !ptid_equal (ptid, minus_one_ptid)))
3694 /* Get ready for the next event. */
3695 if (target_can_async_p ())
3696 target_async (inferior_event_handler, 0);
3702 kill_callback (struct lwp_info *lp, void *data)
3704 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3707 kill (ptid_get_lwp (lp->ptid), SIGKILL);
3708 if (debug_linux_nat)
3709 fprintf_unfiltered (gdb_stdlog,
3710 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3711 target_pid_to_str (lp->ptid),
3712 errno ? safe_strerror (errno) : "OK");
3714 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3717 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3718 if (debug_linux_nat)
3719 fprintf_unfiltered (gdb_stdlog,
3720 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3721 target_pid_to_str (lp->ptid),
3722 errno ? safe_strerror (errno) : "OK");
3728 kill_wait_callback (struct lwp_info *lp, void *data)
3732 /* We must make sure that there are no pending events (delayed
3733 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3734 program doesn't interfere with any following debugging session. */
3736 /* For cloned processes we must check both with __WCLONE and
3737 without, since the exit status of a cloned process isn't reported
3743 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3744 if (pid != (pid_t) -1)
3746 if (debug_linux_nat)
3747 fprintf_unfiltered (gdb_stdlog,
3748 "KWC: wait %s received unknown.\n",
3749 target_pid_to_str (lp->ptid));
3750 /* The Linux kernel sometimes fails to kill a thread
3751 completely after PTRACE_KILL; that goes from the stop
3752 point in do_fork out to the one in
3753 get_signal_to_deliever and waits again. So kill it
3755 kill_callback (lp, NULL);
3758 while (pid == ptid_get_lwp (lp->ptid));
3760 gdb_assert (pid == -1 && errno == ECHILD);
3765 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3766 if (pid != (pid_t) -1)
3768 if (debug_linux_nat)
3769 fprintf_unfiltered (gdb_stdlog,
3770 "KWC: wait %s received unk.\n",
3771 target_pid_to_str (lp->ptid));
3772 /* See the call to kill_callback above. */
3773 kill_callback (lp, NULL);
3776 while (pid == ptid_get_lwp (lp->ptid));
3778 gdb_assert (pid == -1 && errno == ECHILD);
3783 linux_nat_kill (struct target_ops *ops)
3785 struct target_waitstatus last;
3789 /* If we're stopped while forking and we haven't followed yet,
3790 kill the other task. We need to do this first because the
3791 parent will be sleeping if this is a vfork. */
3793 get_last_target_status (&last_ptid, &last);
3795 if (last.kind == TARGET_WAITKIND_FORKED
3796 || last.kind == TARGET_WAITKIND_VFORKED)
3798 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3801 /* Let the arch-specific native code know this process is
3803 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3806 if (forks_exist_p ())
3807 linux_fork_killall ();
3810 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3812 /* Stop all threads before killing them, since ptrace requires
3813 that the thread is stopped to sucessfully PTRACE_KILL. */
3814 iterate_over_lwps (ptid, stop_callback, NULL);
3815 /* ... and wait until all of them have reported back that
3816 they're no longer running. */
3817 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3819 /* Kill all LWP's ... */
3820 iterate_over_lwps (ptid, kill_callback, NULL);
3822 /* ... and wait until we've flushed all events. */
3823 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3826 target_mourn_inferior ();
3830 linux_nat_mourn_inferior (struct target_ops *ops)
3832 int pid = ptid_get_pid (inferior_ptid);
3834 purge_lwp_list (pid);
3836 if (! forks_exist_p ())
3837 /* Normal case, no other forks available. */
3838 linux_ops->to_mourn_inferior (ops);
3840 /* Multi-fork case. The current inferior_ptid has exited, but
3841 there are other viable forks to debug. Delete the exiting
3842 one and context-switch to the first available. */
3843 linux_fork_mourn_inferior ();
3845 /* Let the arch-specific native code know this process is gone. */
3846 linux_nat_forget_process (pid);
3849 /* Convert a native/host siginfo object, into/from the siginfo in the
3850 layout of the inferiors' architecture. */
3853 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3857 if (linux_nat_siginfo_fixup != NULL)
3858 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3860 /* If there was no callback, or the callback didn't do anything,
3861 then just do a straight memcpy. */
3865 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3867 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3872 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3873 const char *annex, gdb_byte *readbuf,
3874 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
3878 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3880 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3881 gdb_assert (readbuf || writebuf);
3883 pid = ptid_get_lwp (inferior_ptid);
3885 pid = ptid_get_pid (inferior_ptid);
3887 if (offset > sizeof (siginfo))
3891 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3895 /* When GDB is built as a 64-bit application, ptrace writes into
3896 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3897 inferior with a 64-bit GDB should look the same as debugging it
3898 with a 32-bit GDB, we need to convert it. GDB core always sees
3899 the converted layout, so any read/write will have to be done
3901 siginfo_fixup (&siginfo, inf_siginfo, 0);
3903 if (offset + len > sizeof (siginfo))
3904 len = sizeof (siginfo) - offset;
3906 if (readbuf != NULL)
3907 memcpy (readbuf, inf_siginfo + offset, len);
3910 memcpy (inf_siginfo + offset, writebuf, len);
3912 /* Convert back to ptrace layout before flushing it out. */
3913 siginfo_fixup (&siginfo, inf_siginfo, 1);
3916 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3925 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3926 const char *annex, gdb_byte *readbuf,
3927 const gdb_byte *writebuf,
3928 ULONGEST offset, LONGEST len)
3930 struct cleanup *old_chain;
3933 if (object == TARGET_OBJECT_SIGNAL_INFO)
3934 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3937 /* The target is connected but no live inferior is selected. Pass
3938 this request down to a lower stratum (e.g., the executable
3940 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3943 old_chain = save_inferior_ptid ();
3945 if (ptid_lwp_p (inferior_ptid))
3946 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3948 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3951 do_cleanups (old_chain);
3956 linux_thread_alive (ptid_t ptid)
3960 gdb_assert (ptid_lwp_p (ptid));
3962 /* Send signal 0 instead of anything ptrace, because ptracing a
3963 running thread errors out claiming that the thread doesn't
3965 err = kill_lwp (ptid_get_lwp (ptid), 0);
3967 if (debug_linux_nat)
3968 fprintf_unfiltered (gdb_stdlog,
3969 "LLTA: KILL(SIG0) %s (%s)\n",
3970 target_pid_to_str (ptid),
3971 err ? safe_strerror (tmp_errno) : "OK");
3980 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3982 return linux_thread_alive (ptid);
3986 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3988 static char buf[64];
3990 if (ptid_lwp_p (ptid)
3991 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
3992 || num_lwps (ptid_get_pid (ptid)) > 1))
3994 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
3998 return normal_pid_to_str (ptid);
4002 linux_nat_thread_name (struct thread_info *thr)
4004 int pid = ptid_get_pid (thr->ptid);
4005 long lwp = ptid_get_lwp (thr->ptid);
4006 #define FORMAT "/proc/%d/task/%ld/comm"
4007 char buf[sizeof (FORMAT) + 30];
4009 char *result = NULL;
4011 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
4012 comm_file = gdb_fopen_cloexec (buf, "r");
4015 /* Not exported by the kernel, so we define it here. */
4017 static char line[COMM_LEN + 1];
4019 if (fgets (line, sizeof (line), comm_file))
4021 char *nl = strchr (line, '\n');
4038 /* Accepts an integer PID; Returns a string representing a file that
4039 can be opened to get the symbols for the child process. */
4042 linux_child_pid_to_exec_file (int pid)
4044 char *name1, *name2;
4046 name1 = xmalloc (PATH_MAX);
4047 name2 = xmalloc (PATH_MAX);
4048 make_cleanup (xfree, name1);
4049 make_cleanup (xfree, name2);
4050 memset (name2, 0, PATH_MAX);
4052 sprintf (name1, "/proc/%d/exe", pid);
4053 if (readlink (name1, name2, PATH_MAX - 1) > 0)
4059 /* Records the thread's register state for the corefile note
4063 linux_nat_collect_thread_registers (const struct regcache *regcache,
4064 ptid_t ptid, bfd *obfd,
4065 char *note_data, int *note_size,
4066 enum gdb_signal stop_signal)
4068 struct gdbarch *gdbarch = get_regcache_arch (regcache);
4069 const struct regset *regset;
4071 gdb_gregset_t gregs;
4072 gdb_fpregset_t fpregs;
4074 core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
4077 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
4079 != NULL && regset->collect_regset != NULL)
4080 regset->collect_regset (regset, regcache, -1, &gregs, sizeof (gregs));
4082 fill_gregset (regcache, &gregs, -1);
4084 note_data = (char *) elfcore_write_prstatus
4085 (obfd, note_data, note_size, ptid_get_lwp (ptid),
4086 gdb_signal_to_host (stop_signal), &gregs);
4089 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
4091 != NULL && regset->collect_regset != NULL)
4092 regset->collect_regset (regset, regcache, -1, &fpregs, sizeof (fpregs));
4094 fill_fpregset (regcache, &fpregs, -1);
4096 note_data = (char *) elfcore_write_prfpreg (obfd, note_data, note_size,
4097 &fpregs, sizeof (fpregs));
4102 /* Fills the "to_make_corefile_note" target vector. Builds the note
4103 section for a corefile, and returns it in a malloc buffer. */
4106 linux_nat_make_corefile_notes (bfd *obfd, int *note_size)
4108 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4109 converted to gdbarch_core_regset_sections, this function can go away. */
4110 return linux_make_corefile_notes (target_gdbarch (), obfd, note_size,
4111 linux_nat_collect_thread_registers);
4114 /* Implement the to_xfer_partial interface for memory reads using the /proc
4115 filesystem. Because we can use a single read() call for /proc, this
4116 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4117 but it doesn't support writes. */
4120 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4121 const char *annex, gdb_byte *readbuf,
4122 const gdb_byte *writebuf,
4123 ULONGEST offset, LONGEST len)
4129 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4132 /* Don't bother for one word. */
4133 if (len < 3 * sizeof (long))
4136 /* We could keep this file open and cache it - possibly one per
4137 thread. That requires some juggling, but is even faster. */
4138 sprintf (filename, "/proc/%d/mem", ptid_get_pid (inferior_ptid));
4139 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
4143 /* If pread64 is available, use it. It's faster if the kernel
4144 supports it (only one syscall), and it's 64-bit safe even on
4145 32-bit platforms (for instance, SPARC debugging a SPARC64
4148 if (pread64 (fd, readbuf, len, offset) != len)
4150 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4161 /* Enumerate spufs IDs for process PID. */
4163 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, LONGEST len)
4165 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4167 LONGEST written = 0;
4170 struct dirent *entry;
4172 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4173 dir = opendir (path);
4178 while ((entry = readdir (dir)) != NULL)
4184 fd = atoi (entry->d_name);
4188 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4189 if (stat (path, &st) != 0)
4191 if (!S_ISDIR (st.st_mode))
4194 if (statfs (path, &stfs) != 0)
4196 if (stfs.f_type != SPUFS_MAGIC)
4199 if (pos >= offset && pos + 4 <= offset + len)
4201 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4211 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4212 object type, using the /proc file system. */
4214 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4215 const char *annex, gdb_byte *readbuf,
4216 const gdb_byte *writebuf,
4217 ULONGEST offset, LONGEST len)
4222 int pid = ptid_get_pid (inferior_ptid);
4229 return spu_enumerate_spu_ids (pid, readbuf, offset, len);
4232 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4233 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4238 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4245 ret = write (fd, writebuf, (size_t) len);
4247 ret = read (fd, readbuf, (size_t) len);
4254 /* Parse LINE as a signal set and add its set bits to SIGS. */
4257 add_line_to_sigset (const char *line, sigset_t *sigs)
4259 int len = strlen (line) - 1;
4263 if (line[len] != '\n')
4264 error (_("Could not parse signal set: %s"), line);
4272 if (*p >= '0' && *p <= '9')
4274 else if (*p >= 'a' && *p <= 'f')
4275 digit = *p - 'a' + 10;
4277 error (_("Could not parse signal set: %s"), line);
4282 sigaddset (sigs, signum + 1);
4284 sigaddset (sigs, signum + 2);
4286 sigaddset (sigs, signum + 3);
4288 sigaddset (sigs, signum + 4);
4294 /* Find process PID's pending signals from /proc/pid/status and set
4298 linux_proc_pending_signals (int pid, sigset_t *pending,
4299 sigset_t *blocked, sigset_t *ignored)
4302 char buffer[PATH_MAX], fname[PATH_MAX];
4303 struct cleanup *cleanup;
4305 sigemptyset (pending);
4306 sigemptyset (blocked);
4307 sigemptyset (ignored);
4308 sprintf (fname, "/proc/%d/status", pid);
4309 procfile = gdb_fopen_cloexec (fname, "r");
4310 if (procfile == NULL)
4311 error (_("Could not open %s"), fname);
4312 cleanup = make_cleanup_fclose (procfile);
4314 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4316 /* Normal queued signals are on the SigPnd line in the status
4317 file. However, 2.6 kernels also have a "shared" pending
4318 queue for delivering signals to a thread group, so check for
4321 Unfortunately some Red Hat kernels include the shared pending
4322 queue but not the ShdPnd status field. */
4324 if (strncmp (buffer, "SigPnd:\t", 8) == 0)
4325 add_line_to_sigset (buffer + 8, pending);
4326 else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
4327 add_line_to_sigset (buffer + 8, pending);
4328 else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
4329 add_line_to_sigset (buffer + 8, blocked);
4330 else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
4331 add_line_to_sigset (buffer + 8, ignored);
4334 do_cleanups (cleanup);
4338 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4339 const char *annex, gdb_byte *readbuf,
4340 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
4342 gdb_assert (object == TARGET_OBJECT_OSDATA);
4344 return linux_common_xfer_osdata (annex, readbuf, offset, len);
4348 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4349 const char *annex, gdb_byte *readbuf,
4350 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
4354 if (object == TARGET_OBJECT_AUXV)
4355 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4358 if (object == TARGET_OBJECT_OSDATA)
4359 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4362 if (object == TARGET_OBJECT_SPU)
4363 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4366 /* GDB calculates all the addresses in possibly larget width of the address.
4367 Address width needs to be masked before its final use - either by
4368 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4370 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4372 if (object == TARGET_OBJECT_MEMORY)
4374 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4376 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4377 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4380 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4385 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4390 cleanup_target_stop (void *arg)
4392 ptid_t *ptid = (ptid_t *) arg;
4394 gdb_assert (arg != NULL);
4397 target_resume (*ptid, 0, GDB_SIGNAL_0);
4400 static VEC(static_tracepoint_marker_p) *
4401 linux_child_static_tracepoint_markers_by_strid (const char *strid)
4403 char s[IPA_CMD_BUF_SIZE];
4404 struct cleanup *old_chain;
4405 int pid = ptid_get_pid (inferior_ptid);
4406 VEC(static_tracepoint_marker_p) *markers = NULL;
4407 struct static_tracepoint_marker *marker = NULL;
4409 ptid_t ptid = ptid_build (pid, 0, 0);
4414 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4415 s[sizeof ("qTfSTM")] = 0;
4417 agent_run_command (pid, s, strlen (s) + 1);
4419 old_chain = make_cleanup (free_current_marker, &marker);
4420 make_cleanup (cleanup_target_stop, &ptid);
4425 marker = XCNEW (struct static_tracepoint_marker);
4429 parse_static_tracepoint_marker_definition (p, &p, marker);
4431 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4433 VEC_safe_push (static_tracepoint_marker_p,
4439 release_static_tracepoint_marker (marker);
4440 memset (marker, 0, sizeof (*marker));
4443 while (*p++ == ','); /* comma-separated list */
4445 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4446 s[sizeof ("qTsSTM")] = 0;
4447 agent_run_command (pid, s, strlen (s) + 1);
4451 do_cleanups (old_chain);
4456 /* Create a prototype generic GNU/Linux target. The client can override
4457 it with local methods. */
4460 linux_target_install_ops (struct target_ops *t)
4462 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4463 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4464 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4465 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4466 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4467 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4468 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4469 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4470 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4471 t->to_post_attach = linux_child_post_attach;
4472 t->to_follow_fork = linux_child_follow_fork;
4473 t->to_make_corefile_notes = linux_nat_make_corefile_notes;
4475 super_xfer_partial = t->to_xfer_partial;
4476 t->to_xfer_partial = linux_xfer_partial;
4478 t->to_static_tracepoint_markers_by_strid
4479 = linux_child_static_tracepoint_markers_by_strid;
4485 struct target_ops *t;
4487 t = inf_ptrace_target ();
4488 linux_target_install_ops (t);
4494 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4496 struct target_ops *t;
4498 t = inf_ptrace_trad_target (register_u_offset);
4499 linux_target_install_ops (t);
4504 /* target_is_async_p implementation. */
4507 linux_nat_is_async_p (void)
4509 /* NOTE: palves 2008-03-21: We're only async when the user requests
4510 it explicitly with the "set target-async" command.
4511 Someday, linux will always be async. */
4512 return target_async_permitted;
4515 /* target_can_async_p implementation. */
4518 linux_nat_can_async_p (void)
4520 /* NOTE: palves 2008-03-21: We're only async when the user requests
4521 it explicitly with the "set target-async" command.
4522 Someday, linux will always be async. */
4523 return target_async_permitted;
4527 linux_nat_supports_non_stop (void)
4532 /* True if we want to support multi-process. To be removed when GDB
4533 supports multi-exec. */
4535 int linux_multi_process = 1;
4538 linux_nat_supports_multi_process (void)
4540 return linux_multi_process;
4544 linux_nat_supports_disable_randomization (void)
4546 #ifdef HAVE_PERSONALITY
4553 static int async_terminal_is_ours = 1;
4555 /* target_terminal_inferior implementation. */
4558 linux_nat_terminal_inferior (void)
4560 if (!target_is_async_p ())
4562 /* Async mode is disabled. */
4563 terminal_inferior ();
4567 terminal_inferior ();
4569 /* Calls to target_terminal_*() are meant to be idempotent. */
4570 if (!async_terminal_is_ours)
4573 delete_file_handler (input_fd);
4574 async_terminal_is_ours = 0;
4578 /* target_terminal_ours implementation. */
4581 linux_nat_terminal_ours (void)
4583 if (!target_is_async_p ())
4585 /* Async mode is disabled. */
4590 /* GDB should never give the terminal to the inferior if the
4591 inferior is running in the background (run&, continue&, etc.),
4592 but claiming it sure should. */
4595 if (async_terminal_is_ours)
4598 clear_sigint_trap ();
4599 add_file_handler (input_fd, stdin_event_handler, 0);
4600 async_terminal_is_ours = 1;
4603 static void (*async_client_callback) (enum inferior_event_type event_type,
4605 static void *async_client_context;
4607 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4608 so we notice when any child changes state, and notify the
4609 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4610 above to wait for the arrival of a SIGCHLD. */
4613 sigchld_handler (int signo)
4615 int old_errno = errno;
4617 if (debug_linux_nat)
4618 ui_file_write_async_safe (gdb_stdlog,
4619 "sigchld\n", sizeof ("sigchld\n") - 1);
4621 if (signo == SIGCHLD
4622 && linux_nat_event_pipe[0] != -1)
4623 async_file_mark (); /* Let the event loop know that there are
4624 events to handle. */
4629 /* Callback registered with the target events file descriptor. */
4632 handle_target_event (int error, gdb_client_data client_data)
4634 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4637 /* Create/destroy the target events pipe. Returns previous state. */
4640 linux_async_pipe (int enable)
4642 int previous = (linux_nat_event_pipe[0] != -1);
4644 if (previous != enable)
4648 /* Block child signals while we create/destroy the pipe, as
4649 their handler writes to it. */
4650 block_child_signals (&prev_mask);
4654 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4655 internal_error (__FILE__, __LINE__,
4656 "creating event pipe failed.");
4658 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4659 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4663 close (linux_nat_event_pipe[0]);
4664 close (linux_nat_event_pipe[1]);
4665 linux_nat_event_pipe[0] = -1;
4666 linux_nat_event_pipe[1] = -1;
4669 restore_child_signals_mask (&prev_mask);
4675 /* target_async implementation. */
4678 linux_nat_async (void (*callback) (enum inferior_event_type event_type,
4679 void *context), void *context)
4681 if (callback != NULL)
4683 async_client_callback = callback;
4684 async_client_context = context;
4685 if (!linux_async_pipe (1))
4687 add_file_handler (linux_nat_event_pipe[0],
4688 handle_target_event, NULL);
4689 /* There may be pending events to handle. Tell the event loop
4696 async_client_callback = callback;
4697 async_client_context = context;
4698 delete_file_handler (linux_nat_event_pipe[0]);
4699 linux_async_pipe (0);
4704 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4708 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4712 if (debug_linux_nat)
4713 fprintf_unfiltered (gdb_stdlog,
4714 "LNSL: running -> suspending %s\n",
4715 target_pid_to_str (lwp->ptid));
4718 if (lwp->last_resume_kind == resume_stop)
4720 if (debug_linux_nat)
4721 fprintf_unfiltered (gdb_stdlog,
4722 "linux-nat: already stopping LWP %ld at "
4724 ptid_get_lwp (lwp->ptid));
4728 stop_callback (lwp, NULL);
4729 lwp->last_resume_kind = resume_stop;
4733 /* Already known to be stopped; do nothing. */
4735 if (debug_linux_nat)
4737 if (find_thread_ptid (lwp->ptid)->stop_requested)
4738 fprintf_unfiltered (gdb_stdlog,
4739 "LNSL: already stopped/stop_requested %s\n",
4740 target_pid_to_str (lwp->ptid));
4742 fprintf_unfiltered (gdb_stdlog,
4743 "LNSL: already stopped/no "
4744 "stop_requested yet %s\n",
4745 target_pid_to_str (lwp->ptid));
4752 linux_nat_stop (ptid_t ptid)
4755 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4757 linux_ops->to_stop (ptid);
4761 linux_nat_close (void)
4763 /* Unregister from the event loop. */
4764 if (linux_nat_is_async_p ())
4765 linux_nat_async (NULL, 0);
4767 if (linux_ops->to_close)
4768 linux_ops->to_close ();
4771 /* When requests are passed down from the linux-nat layer to the
4772 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4773 used. The address space pointer is stored in the inferior object,
4774 but the common code that is passed such ptid can't tell whether
4775 lwpid is a "main" process id or not (it assumes so). We reverse
4776 look up the "main" process id from the lwp here. */
4778 static struct address_space *
4779 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4781 struct lwp_info *lwp;
4782 struct inferior *inf;
4785 pid = ptid_get_lwp (ptid);
4786 if (ptid_get_lwp (ptid) == 0)
4788 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4790 lwp = find_lwp_pid (ptid);
4791 pid = ptid_get_pid (lwp->ptid);
4795 /* A (pid,lwpid,0) ptid. */
4796 pid = ptid_get_pid (ptid);
4799 inf = find_inferior_pid (pid);
4800 gdb_assert (inf != NULL);
4804 /* Return the cached value of the processor core for thread PTID. */
4807 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4809 struct lwp_info *info = find_lwp_pid (ptid);
4817 linux_nat_add_target (struct target_ops *t)
4819 /* Save the provided single-threaded target. We save this in a separate
4820 variable because another target we've inherited from (e.g. inf-ptrace)
4821 may have saved a pointer to T; we want to use it for the final
4822 process stratum target. */
4823 linux_ops_saved = *t;
4824 linux_ops = &linux_ops_saved;
4826 /* Override some methods for multithreading. */
4827 t->to_create_inferior = linux_nat_create_inferior;
4828 t->to_attach = linux_nat_attach;
4829 t->to_detach = linux_nat_detach;
4830 t->to_resume = linux_nat_resume;
4831 t->to_wait = linux_nat_wait;
4832 t->to_pass_signals = linux_nat_pass_signals;
4833 t->to_xfer_partial = linux_nat_xfer_partial;
4834 t->to_kill = linux_nat_kill;
4835 t->to_mourn_inferior = linux_nat_mourn_inferior;
4836 t->to_thread_alive = linux_nat_thread_alive;
4837 t->to_pid_to_str = linux_nat_pid_to_str;
4838 t->to_thread_name = linux_nat_thread_name;
4839 t->to_has_thread_control = tc_schedlock;
4840 t->to_thread_address_space = linux_nat_thread_address_space;
4841 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4842 t->to_stopped_data_address = linux_nat_stopped_data_address;
4844 t->to_can_async_p = linux_nat_can_async_p;
4845 t->to_is_async_p = linux_nat_is_async_p;
4846 t->to_supports_non_stop = linux_nat_supports_non_stop;
4847 t->to_async = linux_nat_async;
4848 t->to_terminal_inferior = linux_nat_terminal_inferior;
4849 t->to_terminal_ours = linux_nat_terminal_ours;
4850 t->to_close = linux_nat_close;
4852 /* Methods for non-stop support. */
4853 t->to_stop = linux_nat_stop;
4855 t->to_supports_multi_process = linux_nat_supports_multi_process;
4857 t->to_supports_disable_randomization
4858 = linux_nat_supports_disable_randomization;
4860 t->to_core_of_thread = linux_nat_core_of_thread;
4862 /* We don't change the stratum; this target will sit at
4863 process_stratum and thread_db will set at thread_stratum. This
4864 is a little strange, since this is a multi-threaded-capable
4865 target, but we want to be on the stack below thread_db, and we
4866 also want to be used for single-threaded processes. */
4871 /* Register a method to call whenever a new thread is attached. */
4873 linux_nat_set_new_thread (struct target_ops *t,
4874 void (*new_thread) (struct lwp_info *))
4876 /* Save the pointer. We only support a single registered instance
4877 of the GNU/Linux native target, so we do not need to map this to
4879 linux_nat_new_thread = new_thread;
4882 /* See declaration in linux-nat.h. */
4885 linux_nat_set_new_fork (struct target_ops *t,
4886 linux_nat_new_fork_ftype *new_fork)
4888 /* Save the pointer. */
4889 linux_nat_new_fork = new_fork;
4892 /* See declaration in linux-nat.h. */
4895 linux_nat_set_forget_process (struct target_ops *t,
4896 linux_nat_forget_process_ftype *fn)
4898 /* Save the pointer. */
4899 linux_nat_forget_process_hook = fn;
4902 /* See declaration in linux-nat.h. */
4905 linux_nat_forget_process (pid_t pid)
4907 if (linux_nat_forget_process_hook != NULL)
4908 linux_nat_forget_process_hook (pid);
4911 /* Register a method that converts a siginfo object between the layout
4912 that ptrace returns, and the layout in the architecture of the
4915 linux_nat_set_siginfo_fixup (struct target_ops *t,
4916 int (*siginfo_fixup) (siginfo_t *,
4920 /* Save the pointer. */
4921 linux_nat_siginfo_fixup = siginfo_fixup;
4924 /* Register a method to call prior to resuming a thread. */
4927 linux_nat_set_prepare_to_resume (struct target_ops *t,
4928 void (*prepare_to_resume) (struct lwp_info *))
4930 /* Save the pointer. */
4931 linux_nat_prepare_to_resume = prepare_to_resume;
4934 /* See linux-nat.h. */
4937 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4941 pid = ptid_get_lwp (ptid);
4943 pid = ptid_get_pid (ptid);
4946 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4949 memset (siginfo, 0, sizeof (*siginfo));
4955 /* Provide a prototype to silence -Wmissing-prototypes. */
4956 extern initialize_file_ftype _initialize_linux_nat;
4959 _initialize_linux_nat (void)
4961 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4962 &debug_linux_nat, _("\
4963 Set debugging of GNU/Linux lwp module."), _("\
4964 Show debugging of GNU/Linux lwp module."), _("\
4965 Enables printf debugging output."),
4967 show_debug_linux_nat,
4968 &setdebuglist, &showdebuglist);
4970 /* Save this mask as the default. */
4971 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4973 /* Install a SIGCHLD handler. */
4974 sigchld_action.sa_handler = sigchld_handler;
4975 sigemptyset (&sigchld_action.sa_mask);
4976 sigchld_action.sa_flags = SA_RESTART;
4978 /* Make it the default. */
4979 sigaction (SIGCHLD, &sigchld_action, NULL);
4981 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4982 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
4983 sigdelset (&suspend_mask, SIGCHLD);
4985 sigemptyset (&blocked_mask);
4989 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4990 the GNU/Linux Threads library and therefore doesn't really belong
4993 /* Read variable NAME in the target and return its value if found.
4994 Otherwise return zero. It is assumed that the type of the variable
4998 get_signo (const char *name)
5000 struct minimal_symbol *ms;
5003 ms = lookup_minimal_symbol (name, NULL, NULL);
5007 if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
5008 sizeof (signo)) != 0)
5014 /* Return the set of signals used by the threads library in *SET. */
5017 lin_thread_get_thread_signals (sigset_t *set)
5019 struct sigaction action;
5020 int restart, cancel;
5022 sigemptyset (&blocked_mask);
5025 restart = get_signo ("__pthread_sig_restart");
5026 cancel = get_signo ("__pthread_sig_cancel");
5028 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5029 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5030 not provide any way for the debugger to query the signal numbers -
5031 fortunately they don't change! */
5034 restart = __SIGRTMIN;
5037 cancel = __SIGRTMIN + 1;
5039 sigaddset (set, restart);
5040 sigaddset (set, cancel);
5042 /* The GNU/Linux Threads library makes terminating threads send a
5043 special "cancel" signal instead of SIGCHLD. Make sure we catch
5044 those (to prevent them from terminating GDB itself, which is
5045 likely to be their default action) and treat them the same way as
5048 action.sa_handler = sigchld_handler;
5049 sigemptyset (&action.sa_mask);
5050 action.sa_flags = SA_RESTART;
5051 sigaction (cancel, &action, NULL);
5053 /* We block the "cancel" signal throughout this code ... */
5054 sigaddset (&blocked_mask, cancel);
5055 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
5057 /* ... except during a sigsuspend. */
5058 sigdelset (&suspend_mask, cancel);