1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2014 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/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
28 #include "gdb_assert.h"
29 #ifdef HAVE_TKILL_SYSCALL
31 #include <sys/syscall.h>
33 #include <sys/ptrace.h>
34 #include "linux-nat.h"
35 #include "linux-ptrace.h"
36 #include "linux-procfs.h"
37 #include "linux-fork.h"
38 #include "gdbthread.h"
42 #include "inf-child.h"
43 #include "inf-ptrace.h"
45 #include <sys/procfs.h> /* for elf_gregset etc. */
46 #include "elf-bfd.h" /* for elfcore_write_* */
47 #include "gregset.h" /* for gregset */
48 #include "gdbcore.h" /* for get_exec_file */
49 #include <ctype.h> /* for isdigit */
50 #include <sys/stat.h> /* for struct stat */
51 #include <fcntl.h> /* for O_RDONLY */
53 #include "event-loop.h"
54 #include "event-top.h"
56 #include <sys/types.h>
58 #include "xml-support.h"
62 #include "linux-osdata.h"
63 #include "linux-tdep.h"
66 #include "tracepoint.h"
67 #include "exceptions.h"
69 #include "target-descriptions.h"
70 #include "filestuff.h"
74 #define SPUFS_MAGIC 0x23c9b64e
77 #ifdef HAVE_PERSONALITY
78 # include <sys/personality.h>
79 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
80 # define ADDR_NO_RANDOMIZE 0x0040000
82 #endif /* HAVE_PERSONALITY */
84 /* This comment documents high-level logic of this file.
86 Waiting for events in sync mode
87 ===============================
89 When waiting for an event in a specific thread, we just use waitpid, passing
90 the specific pid, and not passing WNOHANG.
92 When waiting for an event in all threads, waitpid is not quite good. Prior to
93 version 2.4, Linux can either wait for event in main thread, or in secondary
94 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
95 miss an event. The solution is to use non-blocking waitpid, together with
96 sigsuspend. First, we use non-blocking waitpid to get an event in the main
97 process, if any. Second, we use non-blocking waitpid with the __WCLONED
98 flag to check for events in cloned processes. If nothing is found, we use
99 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
100 happened to a child process -- and SIGCHLD will be delivered both for events
101 in main debugged process and in cloned processes. As soon as we know there's
102 an event, we get back to calling nonblocking waitpid with and without
105 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
106 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
107 blocked, the signal becomes pending and sigsuspend immediately
108 notices it and returns.
110 Waiting for events in async mode
111 ================================
113 In async mode, GDB should always be ready to handle both user input
114 and target events, so neither blocking waitpid nor sigsuspend are
115 viable options. Instead, we should asynchronously notify the GDB main
116 event loop whenever there's an unprocessed event from the target. We
117 detect asynchronous target events by handling SIGCHLD signals. To
118 notify the event loop about target events, the self-pipe trick is used
119 --- a pipe is registered as waitable event source in the event loop,
120 the event loop select/poll's on the read end of this pipe (as well on
121 other event sources, e.g., stdin), and the SIGCHLD handler writes a
122 byte to this pipe. This is more portable than relying on
123 pselect/ppoll, since on kernels that lack those syscalls, libc
124 emulates them with select/poll+sigprocmask, and that is racy
125 (a.k.a. plain broken).
127 Obviously, if we fail to notify the event loop if there's a target
128 event, it's bad. OTOH, if we notify the event loop when there's no
129 event from the target, linux_nat_wait will detect that there's no real
130 event to report, and return event of type TARGET_WAITKIND_IGNORE.
131 This is mostly harmless, but it will waste time and is better avoided.
133 The main design point is that every time GDB is outside linux-nat.c,
134 we have a SIGCHLD handler installed that is called when something
135 happens to the target and notifies the GDB event loop. Whenever GDB
136 core decides to handle the event, and calls into linux-nat.c, we
137 process things as in sync mode, except that the we never block in
140 While processing an event, we may end up momentarily blocked in
141 waitpid calls. Those waitpid calls, while blocking, are guarantied to
142 return quickly. E.g., in all-stop mode, before reporting to the core
143 that an LWP hit a breakpoint, all LWPs are stopped by sending them
144 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
145 Note that this is different from blocking indefinitely waiting for the
146 next event --- here, we're already handling an event.
151 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
152 signal is not entirely significant; we just need for a signal to be delivered,
153 so that we can intercept it. SIGSTOP's advantage is that it can not be
154 blocked. A disadvantage is that it is not a real-time signal, so it can only
155 be queued once; we do not keep track of other sources of SIGSTOP.
157 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
158 use them, because they have special behavior when the signal is generated -
159 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
160 kills the entire thread group.
162 A delivered SIGSTOP would stop the entire thread group, not just the thread we
163 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
164 cancel it (by PTRACE_CONT without passing SIGSTOP).
166 We could use a real-time signal instead. This would solve those problems; we
167 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
168 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
169 generates it, and there are races with trying to find a signal that is not
173 #define O_LARGEFILE 0
176 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
177 the use of the multi-threaded target. */
178 static struct target_ops *linux_ops;
179 static struct target_ops linux_ops_saved;
181 /* The method to call, if any, when a new thread is attached. */
182 static void (*linux_nat_new_thread) (struct lwp_info *);
184 /* The method to call, if any, when a new fork is attached. */
185 static linux_nat_new_fork_ftype *linux_nat_new_fork;
187 /* The method to call, if any, when a process is no longer
189 static linux_nat_forget_process_ftype *linux_nat_forget_process_hook;
191 /* Hook to call prior to resuming a thread. */
192 static void (*linux_nat_prepare_to_resume) (struct lwp_info *);
194 /* The method to call, if any, when the siginfo object needs to be
195 converted between the layout returned by ptrace, and the layout in
196 the architecture of the inferior. */
197 static int (*linux_nat_siginfo_fixup) (siginfo_t *,
201 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
202 Called by our to_xfer_partial. */
203 static target_xfer_partial_ftype *super_xfer_partial;
205 /* The saved to_close method, inherited from inf-ptrace.c.
206 Called by our to_close. */
207 static void (*super_close) (struct target_ops *);
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 int kill_lwp (int lwpid, int signo);
273 static int stop_callback (struct lwp_info *lp, void *data);
275 static void block_child_signals (sigset_t *prev_mask);
276 static void restore_child_signals_mask (sigset_t *prev_mask);
279 static struct lwp_info *add_lwp (ptid_t ptid);
280 static void purge_lwp_list (int pid);
281 static void delete_lwp (ptid_t ptid);
282 static struct lwp_info *find_lwp_pid (ptid_t ptid);
285 /* Trivial list manipulation functions to keep track of a list of
286 new stopped processes. */
288 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
290 struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
293 new_pid->status = status;
294 new_pid->next = *listp;
299 in_pid_list_p (struct simple_pid_list *list, int pid)
301 struct simple_pid_list *p;
303 for (p = list; p != NULL; p = p->next)
310 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
312 struct simple_pid_list **p;
314 for (p = listp; *p != NULL; p = &(*p)->next)
315 if ((*p)->pid == pid)
317 struct simple_pid_list *next = (*p)->next;
319 *statusp = (*p)->status;
327 /* Initialize ptrace warnings and check for supported ptrace
328 features given PID. */
331 linux_init_ptrace (pid_t pid)
333 linux_enable_event_reporting (pid);
334 linux_ptrace_init_warnings ();
338 linux_child_post_attach (struct target_ops *self, int pid)
340 linux_init_ptrace (pid);
344 linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
346 linux_init_ptrace (ptid_get_pid (ptid));
349 /* Return the number of known LWPs in the tgid given by PID. */
357 for (lp = lwp_list; lp; lp = lp->next)
358 if (ptid_get_pid (lp->ptid) == pid)
364 /* Call delete_lwp with prototype compatible for make_cleanup. */
367 delete_lwp_cleanup (void *lp_voidp)
369 struct lwp_info *lp = lp_voidp;
371 delete_lwp (lp->ptid);
375 linux_child_follow_fork (struct target_ops *ops, int follow_child,
379 int parent_pid, child_pid;
381 has_vforked = (inferior_thread ()->pending_follow.kind
382 == TARGET_WAITKIND_VFORKED);
383 parent_pid = ptid_get_lwp (inferior_ptid);
385 parent_pid = ptid_get_pid (inferior_ptid);
387 = ptid_get_pid (inferior_thread ()->pending_follow.value.related_pid);
390 && !non_stop /* Non-stop always resumes both branches. */
391 && (!target_is_async_p () || sync_execution)
392 && !(follow_child || detach_fork || sched_multi))
394 /* The parent stays blocked inside the vfork syscall until the
395 child execs or exits. If we don't let the child run, then
396 the parent stays blocked. If we're telling the parent to run
397 in the foreground, the user will not be able to ctrl-c to get
398 back the terminal, effectively hanging the debug session. */
399 fprintf_filtered (gdb_stderr, _("\
400 Can not resume the parent process over vfork in the foreground while\n\
401 holding the child stopped. Try \"set detach-on-fork\" or \
402 \"set schedule-multiple\".\n"));
403 /* FIXME output string > 80 columns. */
409 struct lwp_info *child_lp = NULL;
411 /* We're already attached to the parent, by default. */
413 /* Detach new forked process? */
416 struct cleanup *old_chain;
418 /* Before detaching from the child, remove all breakpoints
419 from it. If we forked, then this has already been taken
420 care of by infrun.c. If we vforked however, any
421 breakpoint inserted in the parent is visible in the
422 child, even those added while stopped in a vfork
423 catchpoint. This will remove the breakpoints from the
424 parent also, but they'll be reinserted below. */
427 /* keep breakpoints list in sync. */
428 remove_breakpoints_pid (ptid_get_pid (inferior_ptid));
431 if (info_verbose || debug_linux_nat)
433 target_terminal_ours ();
434 fprintf_filtered (gdb_stdlog,
435 "Detaching after fork from "
436 "child process %d.\n",
440 old_chain = save_inferior_ptid ();
441 inferior_ptid = ptid_build (child_pid, child_pid, 0);
443 child_lp = add_lwp (inferior_ptid);
444 child_lp->stopped = 1;
445 child_lp->last_resume_kind = resume_stop;
446 make_cleanup (delete_lwp_cleanup, child_lp);
448 if (linux_nat_prepare_to_resume != NULL)
449 linux_nat_prepare_to_resume (child_lp);
450 ptrace (PTRACE_DETACH, child_pid, 0, 0);
452 do_cleanups (old_chain);
456 struct inferior *parent_inf, *child_inf;
457 struct cleanup *old_chain;
459 /* Add process to GDB's tables. */
460 child_inf = add_inferior (child_pid);
462 parent_inf = current_inferior ();
463 child_inf->attach_flag = parent_inf->attach_flag;
464 copy_terminal_info (child_inf, parent_inf);
465 child_inf->gdbarch = parent_inf->gdbarch;
466 copy_inferior_target_desc_info (child_inf, parent_inf);
468 old_chain = save_inferior_ptid ();
469 save_current_program_space ();
471 inferior_ptid = ptid_build (child_pid, child_pid, 0);
472 add_thread (inferior_ptid);
473 child_lp = add_lwp (inferior_ptid);
474 child_lp->stopped = 1;
475 child_lp->last_resume_kind = resume_stop;
476 child_inf->symfile_flags = SYMFILE_NO_READ;
478 /* If this is a vfork child, then the address-space is
479 shared with the parent. */
482 child_inf->pspace = parent_inf->pspace;
483 child_inf->aspace = parent_inf->aspace;
485 /* The parent will be frozen until the child is done
486 with the shared region. Keep track of the
488 child_inf->vfork_parent = parent_inf;
489 child_inf->pending_detach = 0;
490 parent_inf->vfork_child = child_inf;
491 parent_inf->pending_detach = 0;
495 child_inf->aspace = new_address_space ();
496 child_inf->pspace = add_program_space (child_inf->aspace);
497 child_inf->removable = 1;
498 set_current_program_space (child_inf->pspace);
499 clone_program_space (child_inf->pspace, parent_inf->pspace);
501 /* Let the shared library layer (solib-svr4) learn about
502 this new process, relocate the cloned exec, pull in
503 shared libraries, and install the solib event
504 breakpoint. If a "cloned-VM" event was propagated
505 better throughout the core, this wouldn't be
507 solib_create_inferior_hook (0);
510 /* Let the thread_db layer learn about this new process. */
511 check_for_thread_db ();
513 do_cleanups (old_chain);
518 struct lwp_info *parent_lp;
519 struct inferior *parent_inf;
521 parent_inf = current_inferior ();
523 /* If we detached from the child, then we have to be careful
524 to not insert breakpoints in the parent until the child
525 is done with the shared memory region. However, if we're
526 staying attached to the child, then we can and should
527 insert breakpoints, so that we can debug it. A
528 subsequent child exec or exit is enough to know when does
529 the child stops using the parent's address space. */
530 parent_inf->waiting_for_vfork_done = detach_fork;
531 parent_inf->pspace->breakpoints_not_allowed = detach_fork;
533 parent_lp = find_lwp_pid (pid_to_ptid (parent_pid));
534 gdb_assert (linux_supports_tracefork () >= 0);
536 if (linux_supports_tracevforkdone ())
539 fprintf_unfiltered (gdb_stdlog,
540 "LCFF: waiting for VFORK_DONE on %d\n",
542 parent_lp->stopped = 1;
544 /* We'll handle the VFORK_DONE event like any other
545 event, in target_wait. */
549 /* We can't insert breakpoints until the child has
550 finished with the shared memory region. We need to
551 wait until that happens. Ideal would be to just
553 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
554 - waitpid (parent_pid, &status, __WALL);
555 However, most architectures can't handle a syscall
556 being traced on the way out if it wasn't traced on
559 We might also think to loop, continuing the child
560 until it exits or gets a SIGTRAP. One problem is
561 that the child might call ptrace with PTRACE_TRACEME.
563 There's no simple and reliable way to figure out when
564 the vforked child will be done with its copy of the
565 shared memory. We could step it out of the syscall,
566 two instructions, let it go, and then single-step the
567 parent once. When we have hardware single-step, this
568 would work; with software single-step it could still
569 be made to work but we'd have to be able to insert
570 single-step breakpoints in the child, and we'd have
571 to insert -just- the single-step breakpoint in the
572 parent. Very awkward.
574 In the end, the best we can do is to make sure it
575 runs for a little while. Hopefully it will be out of
576 range of any breakpoints we reinsert. Usually this
577 is only the single-step breakpoint at vfork's return
581 fprintf_unfiltered (gdb_stdlog,
582 "LCFF: no VFORK_DONE "
583 "support, sleeping a bit\n");
587 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
588 and leave it pending. The next linux_nat_resume call
589 will notice a pending event, and bypasses actually
590 resuming the inferior. */
591 parent_lp->status = 0;
592 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
593 parent_lp->stopped = 1;
595 /* If we're in async mode, need to tell the event loop
596 there's something here to process. */
597 if (target_can_async_p ())
604 struct inferior *parent_inf, *child_inf;
605 struct lwp_info *child_lp;
606 struct program_space *parent_pspace;
608 if (info_verbose || debug_linux_nat)
610 target_terminal_ours ();
612 fprintf_filtered (gdb_stdlog,
613 _("Attaching after process %d "
614 "vfork to child process %d.\n"),
615 parent_pid, child_pid);
617 fprintf_filtered (gdb_stdlog,
618 _("Attaching after process %d "
619 "fork to child process %d.\n"),
620 parent_pid, child_pid);
623 /* Add the new inferior first, so that the target_detach below
624 doesn't unpush the target. */
626 child_inf = add_inferior (child_pid);
628 parent_inf = current_inferior ();
629 child_inf->attach_flag = parent_inf->attach_flag;
630 copy_terminal_info (child_inf, parent_inf);
631 child_inf->gdbarch = parent_inf->gdbarch;
632 copy_inferior_target_desc_info (child_inf, parent_inf);
634 parent_pspace = parent_inf->pspace;
636 /* If we're vforking, we want to hold on to the parent until the
637 child exits or execs. At child exec or exit time we can
638 remove the old breakpoints from the parent and detach or
639 resume debugging it. Otherwise, detach the parent now; we'll
640 want to reuse it's program/address spaces, but we can't set
641 them to the child before removing breakpoints from the
642 parent, otherwise, the breakpoints module could decide to
643 remove breakpoints from the wrong process (since they'd be
644 assigned to the same address space). */
648 gdb_assert (child_inf->vfork_parent == NULL);
649 gdb_assert (parent_inf->vfork_child == NULL);
650 child_inf->vfork_parent = parent_inf;
651 child_inf->pending_detach = 0;
652 parent_inf->vfork_child = child_inf;
653 parent_inf->pending_detach = detach_fork;
654 parent_inf->waiting_for_vfork_done = 0;
656 else if (detach_fork)
657 target_detach (NULL, 0);
659 /* Note that the detach above makes PARENT_INF dangling. */
661 /* Add the child thread to the appropriate lists, and switch to
662 this new thread, before cloning the program space, and
663 informing the solib layer about this new process. */
665 inferior_ptid = ptid_build (child_pid, child_pid, 0);
666 add_thread (inferior_ptid);
667 child_lp = add_lwp (inferior_ptid);
668 child_lp->stopped = 1;
669 child_lp->last_resume_kind = resume_stop;
671 /* If this is a vfork child, then the address-space is shared
672 with the parent. If we detached from the parent, then we can
673 reuse the parent's program/address spaces. */
674 if (has_vforked || detach_fork)
676 child_inf->pspace = parent_pspace;
677 child_inf->aspace = child_inf->pspace->aspace;
681 child_inf->aspace = new_address_space ();
682 child_inf->pspace = add_program_space (child_inf->aspace);
683 child_inf->removable = 1;
684 child_inf->symfile_flags = SYMFILE_NO_READ;
685 set_current_program_space (child_inf->pspace);
686 clone_program_space (child_inf->pspace, parent_pspace);
688 /* Let the shared library layer (solib-svr4) learn about
689 this new process, relocate the cloned exec, pull in
690 shared libraries, and install the solib event breakpoint.
691 If a "cloned-VM" event was propagated better throughout
692 the core, this wouldn't be required. */
693 solib_create_inferior_hook (0);
696 /* Let the thread_db layer learn about this new process. */
697 check_for_thread_db ();
705 linux_child_insert_fork_catchpoint (struct target_ops *self, int pid)
707 return !linux_supports_tracefork ();
711 linux_child_remove_fork_catchpoint (struct target_ops *self, int pid)
717 linux_child_insert_vfork_catchpoint (struct target_ops *self, int pid)
719 return !linux_supports_tracefork ();
723 linux_child_remove_vfork_catchpoint (struct target_ops *self, int pid)
729 linux_child_insert_exec_catchpoint (struct target_ops *self, int pid)
731 return !linux_supports_tracefork ();
735 linux_child_remove_exec_catchpoint (struct target_ops *self, int pid)
741 linux_child_set_syscall_catchpoint (struct target_ops *self,
742 int pid, int needed, int any_count,
743 int table_size, int *table)
745 if (!linux_supports_tracesysgood ())
748 /* On GNU/Linux, we ignore the arguments. It means that we only
749 enable the syscall catchpoints, but do not disable them.
751 Also, we do not use the `table' information because we do not
752 filter system calls here. We let GDB do the logic for us. */
756 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
757 are processes sharing the same VM space. A multi-threaded process
758 is basically a group of such processes. However, such a grouping
759 is almost entirely a user-space issue; the kernel doesn't enforce
760 such a grouping at all (this might change in the future). In
761 general, we'll rely on the threads library (i.e. the GNU/Linux
762 Threads library) to provide such a grouping.
764 It is perfectly well possible to write a multi-threaded application
765 without the assistance of a threads library, by using the clone
766 system call directly. This module should be able to give some
767 rudimentary support for debugging such applications if developers
768 specify the CLONE_PTRACE flag in the clone system call, and are
769 using the Linux kernel 2.4 or above.
771 Note that there are some peculiarities in GNU/Linux that affect
774 - In general one should specify the __WCLONE flag to waitpid in
775 order to make it report events for any of the cloned processes
776 (and leave it out for the initial process). However, if a cloned
777 process has exited the exit status is only reported if the
778 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
779 we cannot use it since GDB must work on older systems too.
781 - When a traced, cloned process exits and is waited for by the
782 debugger, the kernel reassigns it to the original parent and
783 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
784 library doesn't notice this, which leads to the "zombie problem":
785 When debugged a multi-threaded process that spawns a lot of
786 threads will run out of processes, even if the threads exit,
787 because the "zombies" stay around. */
789 /* List of known LWPs. */
790 struct lwp_info *lwp_list;
793 /* Original signal mask. */
794 static sigset_t normal_mask;
796 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
797 _initialize_linux_nat. */
798 static sigset_t suspend_mask;
800 /* Signals to block to make that sigsuspend work. */
801 static sigset_t blocked_mask;
803 /* SIGCHLD action. */
804 struct sigaction sigchld_action;
806 /* Block child signals (SIGCHLD and linux threads signals), and store
807 the previous mask in PREV_MASK. */
810 block_child_signals (sigset_t *prev_mask)
812 /* Make sure SIGCHLD is blocked. */
813 if (!sigismember (&blocked_mask, SIGCHLD))
814 sigaddset (&blocked_mask, SIGCHLD);
816 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
819 /* Restore child signals mask, previously returned by
820 block_child_signals. */
823 restore_child_signals_mask (sigset_t *prev_mask)
825 sigprocmask (SIG_SETMASK, prev_mask, NULL);
828 /* Mask of signals to pass directly to the inferior. */
829 static sigset_t pass_mask;
831 /* Update signals to pass to the inferior. */
833 linux_nat_pass_signals (struct target_ops *self,
834 int numsigs, unsigned char *pass_signals)
838 sigemptyset (&pass_mask);
840 for (signo = 1; signo < NSIG; signo++)
842 int target_signo = gdb_signal_from_host (signo);
843 if (target_signo < numsigs && pass_signals[target_signo])
844 sigaddset (&pass_mask, signo);
850 /* Prototypes for local functions. */
851 static int stop_wait_callback (struct lwp_info *lp, void *data);
852 static int linux_thread_alive (ptid_t ptid);
853 static char *linux_child_pid_to_exec_file (struct target_ops *self, int pid);
857 /* Destroy and free LP. */
860 lwp_free (struct lwp_info *lp)
862 xfree (lp->arch_private);
866 /* Remove all LWPs belong to PID from the lwp list. */
869 purge_lwp_list (int pid)
871 struct lwp_info *lp, *lpprev, *lpnext;
875 for (lp = lwp_list; lp; lp = lpnext)
879 if (ptid_get_pid (lp->ptid) == pid)
884 lpprev->next = lp->next;
893 /* Add the LWP specified by PTID to the list. PTID is the first LWP
894 in the process. Return a pointer to the structure describing the
897 This differs from add_lwp in that we don't let the arch specific
898 bits know about this new thread. Current clients of this callback
899 take the opportunity to install watchpoints in the new thread, and
900 we shouldn't do that for the first thread. If we're spawning a
901 child ("run"), the thread executes the shell wrapper first, and we
902 shouldn't touch it until it execs the program we want to debug.
903 For "attach", it'd be okay to call the callback, but it's not
904 necessary, because watchpoints can't yet have been inserted into
907 static struct lwp_info *
908 add_initial_lwp (ptid_t ptid)
912 gdb_assert (ptid_lwp_p (ptid));
914 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
916 memset (lp, 0, sizeof (struct lwp_info));
918 lp->last_resume_kind = resume_continue;
919 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
930 /* Add the LWP specified by PID to the list. Return a pointer to the
931 structure describing the new LWP. The LWP should already be
934 static struct lwp_info *
935 add_lwp (ptid_t ptid)
939 lp = add_initial_lwp (ptid);
941 /* Let the arch specific bits know about this new thread. Current
942 clients of this callback take the opportunity to install
943 watchpoints in the new thread. We don't do this for the first
944 thread though. See add_initial_lwp. */
945 if (linux_nat_new_thread != NULL)
946 linux_nat_new_thread (lp);
951 /* Remove the LWP specified by PID from the list. */
954 delete_lwp (ptid_t ptid)
956 struct lwp_info *lp, *lpprev;
960 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
961 if (ptid_equal (lp->ptid, ptid))
968 lpprev->next = lp->next;
975 /* Return a pointer to the structure describing the LWP corresponding
976 to PID. If no corresponding LWP could be found, return NULL. */
978 static struct lwp_info *
979 find_lwp_pid (ptid_t ptid)
984 if (ptid_lwp_p (ptid))
985 lwp = ptid_get_lwp (ptid);
987 lwp = ptid_get_pid (ptid);
989 for (lp = lwp_list; lp; lp = lp->next)
990 if (lwp == ptid_get_lwp (lp->ptid))
996 /* Call CALLBACK with its second argument set to DATA for every LWP in
997 the list. If CALLBACK returns 1 for a particular LWP, return a
998 pointer to the structure describing that LWP immediately.
999 Otherwise return NULL. */
1002 iterate_over_lwps (ptid_t filter,
1003 int (*callback) (struct lwp_info *, void *),
1006 struct lwp_info *lp, *lpnext;
1008 for (lp = lwp_list; lp; lp = lpnext)
1012 if (ptid_match (lp->ptid, filter))
1014 if ((*callback) (lp, data))
1022 /* Update our internal state when changing from one checkpoint to
1023 another indicated by NEW_PTID. We can only switch single-threaded
1024 applications, so we only create one new LWP, and the previous list
1028 linux_nat_switch_fork (ptid_t new_ptid)
1030 struct lwp_info *lp;
1032 purge_lwp_list (ptid_get_pid (inferior_ptid));
1034 lp = add_lwp (new_ptid);
1037 /* This changes the thread's ptid while preserving the gdb thread
1038 num. Also changes the inferior pid, while preserving the
1040 thread_change_ptid (inferior_ptid, new_ptid);
1042 /* We've just told GDB core that the thread changed target id, but,
1043 in fact, it really is a different thread, with different register
1045 registers_changed ();
1048 /* Handle the exit of a single thread LP. */
1051 exit_lwp (struct lwp_info *lp)
1053 struct thread_info *th = find_thread_ptid (lp->ptid);
1057 if (print_thread_events)
1058 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
1060 delete_thread (lp->ptid);
1063 delete_lwp (lp->ptid);
1066 /* Wait for the LWP specified by LP, which we have just attached to.
1067 Returns a wait status for that LWP, to cache. */
1070 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
1073 pid_t new_pid, pid = ptid_get_lwp (ptid);
1076 if (linux_proc_pid_is_stopped (pid))
1078 if (debug_linux_nat)
1079 fprintf_unfiltered (gdb_stdlog,
1080 "LNPAW: Attaching to a stopped process\n");
1082 /* The process is definitely stopped. It is in a job control
1083 stop, unless the kernel predates the TASK_STOPPED /
1084 TASK_TRACED distinction, in which case it might be in a
1085 ptrace stop. Make sure it is in a ptrace stop; from there we
1086 can kill it, signal it, et cetera.
1088 First make sure there is a pending SIGSTOP. Since we are
1089 already attached, the process can not transition from stopped
1090 to running without a PTRACE_CONT; so we know this signal will
1091 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1092 probably already in the queue (unless this kernel is old
1093 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1094 is not an RT signal, it can only be queued once. */
1095 kill_lwp (pid, SIGSTOP);
1097 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1098 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1099 ptrace (PTRACE_CONT, pid, 0, 0);
1102 /* Make sure the initial process is stopped. The user-level threads
1103 layer might want to poke around in the inferior, and that won't
1104 work if things haven't stabilized yet. */
1105 new_pid = my_waitpid (pid, &status, 0);
1106 if (new_pid == -1 && errno == ECHILD)
1109 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
1111 /* Try again with __WCLONE to check cloned processes. */
1112 new_pid = my_waitpid (pid, &status, __WCLONE);
1116 gdb_assert (pid == new_pid);
1118 if (!WIFSTOPPED (status))
1120 /* The pid we tried to attach has apparently just exited. */
1121 if (debug_linux_nat)
1122 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1123 pid, status_to_str (status));
1127 if (WSTOPSIG (status) != SIGSTOP)
1130 if (debug_linux_nat)
1131 fprintf_unfiltered (gdb_stdlog,
1132 "LNPAW: Received %s after attaching\n",
1133 status_to_str (status));
1139 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1140 the new LWP could not be attached, or 1 if we're already auto
1141 attached to this thread, but haven't processed the
1142 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1143 its existance, without considering it an error. */
1146 lin_lwp_attach_lwp (ptid_t ptid)
1148 struct lwp_info *lp;
1151 gdb_assert (ptid_lwp_p (ptid));
1153 lp = find_lwp_pid (ptid);
1154 lwpid = ptid_get_lwp (ptid);
1156 /* We assume that we're already attached to any LWP that has an id
1157 equal to the overall process id, and to any LWP that is already
1158 in our list of LWPs. If we're not seeing exit events from threads
1159 and we've had PID wraparound since we last tried to stop all threads,
1160 this assumption might be wrong; fortunately, this is very unlikely
1162 if (lwpid != ptid_get_pid (ptid) && lp == NULL)
1164 int status, cloned = 0, signalled = 0;
1166 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1168 if (linux_supports_tracefork ())
1170 /* If we haven't stopped all threads when we get here,
1171 we may have seen a thread listed in thread_db's list,
1172 but not processed the PTRACE_EVENT_CLONE yet. If
1173 that's the case, ignore this new thread, and let
1174 normal event handling discover it later. */
1175 if (in_pid_list_p (stopped_pids, lwpid))
1177 /* We've already seen this thread stop, but we
1178 haven't seen the PTRACE_EVENT_CLONE extended
1187 /* See if we've got a stop for this new child
1188 pending. If so, we're already attached. */
1189 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1190 if (new_pid == -1 && errno == ECHILD)
1191 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1194 if (WIFSTOPPED (status))
1195 add_to_pid_list (&stopped_pids, lwpid, status);
1201 /* If we fail to attach to the thread, issue a warning,
1202 but continue. One way this can happen is if thread
1203 creation is interrupted; as of Linux kernel 2.6.19, a
1204 bug may place threads in the thread list and then fail
1206 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1207 safe_strerror (errno));
1211 if (debug_linux_nat)
1212 fprintf_unfiltered (gdb_stdlog,
1213 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1214 target_pid_to_str (ptid));
1216 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1217 if (!WIFSTOPPED (status))
1220 lp = add_lwp (ptid);
1222 lp->cloned = cloned;
1223 lp->signalled = signalled;
1224 if (WSTOPSIG (status) != SIGSTOP)
1227 lp->status = status;
1230 target_post_attach (ptid_get_lwp (lp->ptid));
1232 if (debug_linux_nat)
1234 fprintf_unfiltered (gdb_stdlog,
1235 "LLAL: waitpid %s received %s\n",
1236 target_pid_to_str (ptid),
1237 status_to_str (status));
1242 /* We assume that the LWP representing the original process is
1243 already stopped. Mark it as stopped in the data structure
1244 that the GNU/linux ptrace layer uses to keep track of
1245 threads. Note that this won't have already been done since
1246 the main thread will have, we assume, been stopped by an
1247 attach from a different layer. */
1249 lp = add_lwp (ptid);
1253 lp->last_resume_kind = resume_stop;
1258 linux_nat_create_inferior (struct target_ops *ops,
1259 char *exec_file, char *allargs, char **env,
1262 #ifdef HAVE_PERSONALITY
1263 int personality_orig = 0, personality_set = 0;
1264 #endif /* HAVE_PERSONALITY */
1266 /* The fork_child mechanism is synchronous and calls target_wait, so
1267 we have to mask the async mode. */
1269 #ifdef HAVE_PERSONALITY
1270 if (disable_randomization)
1273 personality_orig = personality (0xffffffff);
1274 if (errno == 0 && !(personality_orig & ADDR_NO_RANDOMIZE))
1276 personality_set = 1;
1277 personality (personality_orig | ADDR_NO_RANDOMIZE);
1279 if (errno != 0 || (personality_set
1280 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE)))
1281 warning (_("Error disabling address space randomization: %s"),
1282 safe_strerror (errno));
1284 #endif /* HAVE_PERSONALITY */
1286 /* Make sure we report all signals during startup. */
1287 linux_nat_pass_signals (ops, 0, NULL);
1289 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1291 #ifdef HAVE_PERSONALITY
1292 if (personality_set)
1295 personality (personality_orig);
1297 warning (_("Error restoring address space randomization: %s"),
1298 safe_strerror (errno));
1300 #endif /* HAVE_PERSONALITY */
1304 linux_nat_attach (struct target_ops *ops, char *args, int from_tty)
1306 struct lwp_info *lp;
1309 volatile struct gdb_exception ex;
1311 /* Make sure we report all signals during attach. */
1312 linux_nat_pass_signals (ops, 0, NULL);
1314 TRY_CATCH (ex, RETURN_MASK_ERROR)
1316 linux_ops->to_attach (ops, args, from_tty);
1320 pid_t pid = parse_pid_to_attach (args);
1321 struct buffer buffer;
1322 char *message, *buffer_s;
1324 message = xstrdup (ex.message);
1325 make_cleanup (xfree, message);
1327 buffer_init (&buffer);
1328 linux_ptrace_attach_fail_reason (pid, &buffer);
1330 buffer_grow_str0 (&buffer, "");
1331 buffer_s = buffer_finish (&buffer);
1332 make_cleanup (xfree, buffer_s);
1334 if (*buffer_s != '\0')
1335 throw_error (ex.error, "warning: %s\n%s", buffer_s, message);
1337 throw_error (ex.error, "%s", message);
1340 /* The ptrace base target adds the main thread with (pid,0,0)
1341 format. Decorate it with lwp info. */
1342 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1343 ptid_get_pid (inferior_ptid),
1345 thread_change_ptid (inferior_ptid, ptid);
1347 /* Add the initial process as the first LWP to the list. */
1348 lp = add_initial_lwp (ptid);
1350 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1352 if (!WIFSTOPPED (status))
1354 if (WIFEXITED (status))
1356 int exit_code = WEXITSTATUS (status);
1358 target_terminal_ours ();
1359 target_mourn_inferior ();
1361 error (_("Unable to attach: program exited normally."));
1363 error (_("Unable to attach: program exited with code %d."),
1366 else if (WIFSIGNALED (status))
1368 enum gdb_signal signo;
1370 target_terminal_ours ();
1371 target_mourn_inferior ();
1373 signo = gdb_signal_from_host (WTERMSIG (status));
1374 error (_("Unable to attach: program terminated with signal "
1376 gdb_signal_to_name (signo),
1377 gdb_signal_to_string (signo));
1380 internal_error (__FILE__, __LINE__,
1381 _("unexpected status %d for PID %ld"),
1382 status, (long) ptid_get_lwp (ptid));
1387 /* Save the wait status to report later. */
1389 if (debug_linux_nat)
1390 fprintf_unfiltered (gdb_stdlog,
1391 "LNA: waitpid %ld, saving status %s\n",
1392 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1394 lp->status = status;
1396 if (target_can_async_p ())
1397 target_async (inferior_event_handler, 0);
1400 /* Get pending status of LP. */
1402 get_pending_status (struct lwp_info *lp, int *status)
1404 enum gdb_signal signo = GDB_SIGNAL_0;
1406 /* If we paused threads momentarily, we may have stored pending
1407 events in lp->status or lp->waitstatus (see stop_wait_callback),
1408 and GDB core hasn't seen any signal for those threads.
1409 Otherwise, the last signal reported to the core is found in the
1410 thread object's stop_signal.
1412 There's a corner case that isn't handled here at present. Only
1413 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1414 stop_signal make sense as a real signal to pass to the inferior.
1415 Some catchpoint related events, like
1416 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1417 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1418 those traps are debug API (ptrace in our case) related and
1419 induced; the inferior wouldn't see them if it wasn't being
1420 traced. Hence, we should never pass them to the inferior, even
1421 when set to pass state. Since this corner case isn't handled by
1422 infrun.c when proceeding with a signal, for consistency, neither
1423 do we handle it here (or elsewhere in the file we check for
1424 signal pass state). Normally SIGTRAP isn't set to pass state, so
1425 this is really a corner case. */
1427 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1428 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1429 else if (lp->status)
1430 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1431 else if (non_stop && !is_executing (lp->ptid))
1433 struct thread_info *tp = find_thread_ptid (lp->ptid);
1435 signo = tp->suspend.stop_signal;
1439 struct target_waitstatus last;
1442 get_last_target_status (&last_ptid, &last);
1444 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1446 struct thread_info *tp = find_thread_ptid (lp->ptid);
1448 signo = tp->suspend.stop_signal;
1454 if (signo == GDB_SIGNAL_0)
1456 if (debug_linux_nat)
1457 fprintf_unfiltered (gdb_stdlog,
1458 "GPT: lwp %s has no pending signal\n",
1459 target_pid_to_str (lp->ptid));
1461 else if (!signal_pass_state (signo))
1463 if (debug_linux_nat)
1464 fprintf_unfiltered (gdb_stdlog,
1465 "GPT: lwp %s had signal %s, "
1466 "but it is in no pass state\n",
1467 target_pid_to_str (lp->ptid),
1468 gdb_signal_to_string (signo));
1472 *status = W_STOPCODE (gdb_signal_to_host (signo));
1474 if (debug_linux_nat)
1475 fprintf_unfiltered (gdb_stdlog,
1476 "GPT: lwp %s has pending signal %s\n",
1477 target_pid_to_str (lp->ptid),
1478 gdb_signal_to_string (signo));
1485 detach_callback (struct lwp_info *lp, void *data)
1487 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1489 if (debug_linux_nat && lp->status)
1490 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1491 strsignal (WSTOPSIG (lp->status)),
1492 target_pid_to_str (lp->ptid));
1494 /* If there is a pending SIGSTOP, get rid of it. */
1497 if (debug_linux_nat)
1498 fprintf_unfiltered (gdb_stdlog,
1499 "DC: Sending SIGCONT to %s\n",
1500 target_pid_to_str (lp->ptid));
1502 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1506 /* We don't actually detach from the LWP that has an id equal to the
1507 overall process id just yet. */
1508 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1512 /* Pass on any pending signal for this LWP. */
1513 get_pending_status (lp, &status);
1515 if (linux_nat_prepare_to_resume != NULL)
1516 linux_nat_prepare_to_resume (lp);
1518 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1519 WSTOPSIG (status)) < 0)
1520 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1521 safe_strerror (errno));
1523 if (debug_linux_nat)
1524 fprintf_unfiltered (gdb_stdlog,
1525 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1526 target_pid_to_str (lp->ptid),
1527 strsignal (WSTOPSIG (status)));
1529 delete_lwp (lp->ptid);
1536 linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
1540 struct lwp_info *main_lwp;
1542 pid = ptid_get_pid (inferior_ptid);
1544 /* Don't unregister from the event loop, as there may be other
1545 inferiors running. */
1547 /* Stop all threads before detaching. ptrace requires that the
1548 thread is stopped to sucessfully detach. */
1549 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1550 /* ... and wait until all of them have reported back that
1551 they're no longer running. */
1552 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1554 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1556 /* Only the initial process should be left right now. */
1557 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1559 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1561 /* Pass on any pending signal for the last LWP. */
1562 if ((args == NULL || *args == '\0')
1563 && get_pending_status (main_lwp, &status) != -1
1564 && WIFSTOPPED (status))
1568 /* Put the signal number in ARGS so that inf_ptrace_detach will
1569 pass it along with PTRACE_DETACH. */
1571 xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
1573 if (debug_linux_nat)
1574 fprintf_unfiltered (gdb_stdlog,
1575 "LND: Sending signal %s to %s\n",
1577 target_pid_to_str (main_lwp->ptid));
1580 if (linux_nat_prepare_to_resume != NULL)
1581 linux_nat_prepare_to_resume (main_lwp);
1582 delete_lwp (main_lwp->ptid);
1584 if (forks_exist_p ())
1586 /* Multi-fork case. The current inferior_ptid is being detached
1587 from, but there are other viable forks to debug. Detach from
1588 the current fork, and context-switch to the first
1590 linux_fork_detach (args, from_tty);
1593 linux_ops->to_detach (ops, args, from_tty);
1599 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1603 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
1605 if (inf->vfork_child != NULL)
1607 if (debug_linux_nat)
1608 fprintf_unfiltered (gdb_stdlog,
1609 "RC: Not resuming %s (vfork parent)\n",
1610 target_pid_to_str (lp->ptid));
1612 else if (lp->status == 0
1613 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
1615 if (debug_linux_nat)
1616 fprintf_unfiltered (gdb_stdlog,
1617 "RC: Resuming sibling %s, %s, %s\n",
1618 target_pid_to_str (lp->ptid),
1619 (signo != GDB_SIGNAL_0
1620 ? strsignal (gdb_signal_to_host (signo))
1622 step ? "step" : "resume");
1624 if (linux_nat_prepare_to_resume != NULL)
1625 linux_nat_prepare_to_resume (lp);
1626 linux_ops->to_resume (linux_ops,
1627 pid_to_ptid (ptid_get_lwp (lp->ptid)),
1631 lp->stopped_by_watchpoint = 0;
1635 if (debug_linux_nat)
1636 fprintf_unfiltered (gdb_stdlog,
1637 "RC: Not resuming sibling %s (has pending)\n",
1638 target_pid_to_str (lp->ptid));
1643 if (debug_linux_nat)
1644 fprintf_unfiltered (gdb_stdlog,
1645 "RC: Not resuming sibling %s (not stopped)\n",
1646 target_pid_to_str (lp->ptid));
1650 /* Resume LWP, with the last stop signal, if it is in pass state. */
1653 linux_nat_resume_callback (struct lwp_info *lp, void *data)
1655 enum gdb_signal signo = GDB_SIGNAL_0;
1659 struct thread_info *thread;
1661 thread = find_thread_ptid (lp->ptid);
1664 if (signal_pass_state (thread->suspend.stop_signal))
1665 signo = thread->suspend.stop_signal;
1666 thread->suspend.stop_signal = GDB_SIGNAL_0;
1670 resume_lwp (lp, 0, signo);
1675 resume_clear_callback (struct lwp_info *lp, void *data)
1678 lp->last_resume_kind = resume_stop;
1683 resume_set_callback (struct lwp_info *lp, void *data)
1686 lp->last_resume_kind = resume_continue;
1691 linux_nat_resume (struct target_ops *ops,
1692 ptid_t ptid, int step, enum gdb_signal signo)
1694 struct lwp_info *lp;
1697 if (debug_linux_nat)
1698 fprintf_unfiltered (gdb_stdlog,
1699 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1700 step ? "step" : "resume",
1701 target_pid_to_str (ptid),
1702 (signo != GDB_SIGNAL_0
1703 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1704 target_pid_to_str (inferior_ptid));
1706 /* A specific PTID means `step only this process id'. */
1707 resume_many = (ptid_equal (minus_one_ptid, ptid)
1708 || ptid_is_pid (ptid));
1710 /* Mark the lwps we're resuming as resumed. */
1711 iterate_over_lwps (ptid, resume_set_callback, NULL);
1713 /* See if it's the current inferior that should be handled
1716 lp = find_lwp_pid (inferior_ptid);
1718 lp = find_lwp_pid (ptid);
1719 gdb_assert (lp != NULL);
1721 /* Remember if we're stepping. */
1723 lp->last_resume_kind = step ? resume_step : resume_continue;
1725 /* If we have a pending wait status for this thread, there is no
1726 point in resuming the process. But first make sure that
1727 linux_nat_wait won't preemptively handle the event - we
1728 should never take this short-circuit if we are going to
1729 leave LP running, since we have skipped resuming all the
1730 other threads. This bit of code needs to be synchronized
1731 with linux_nat_wait. */
1733 if (lp->status && WIFSTOPPED (lp->status))
1736 && WSTOPSIG (lp->status)
1737 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1739 if (debug_linux_nat)
1740 fprintf_unfiltered (gdb_stdlog,
1741 "LLR: Not short circuiting for ignored "
1742 "status 0x%x\n", lp->status);
1744 /* FIXME: What should we do if we are supposed to continue
1745 this thread with a signal? */
1746 gdb_assert (signo == GDB_SIGNAL_0);
1747 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1752 if (lp->status || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1754 /* FIXME: What should we do if we are supposed to continue
1755 this thread with a signal? */
1756 gdb_assert (signo == GDB_SIGNAL_0);
1758 if (debug_linux_nat)
1759 fprintf_unfiltered (gdb_stdlog,
1760 "LLR: Short circuiting for status 0x%x\n",
1763 if (target_can_async_p ())
1765 target_async (inferior_event_handler, 0);
1766 /* Tell the event loop we have something to process. */
1772 /* Mark LWP as not stopped to prevent it from being continued by
1773 linux_nat_resume_callback. */
1777 iterate_over_lwps (ptid, linux_nat_resume_callback, NULL);
1779 /* Convert to something the lower layer understands. */
1780 ptid = pid_to_ptid (ptid_get_lwp (lp->ptid));
1782 if (linux_nat_prepare_to_resume != NULL)
1783 linux_nat_prepare_to_resume (lp);
1784 linux_ops->to_resume (linux_ops, ptid, step, signo);
1785 lp->stopped_by_watchpoint = 0;
1787 if (debug_linux_nat)
1788 fprintf_unfiltered (gdb_stdlog,
1789 "LLR: %s %s, %s (resume event thread)\n",
1790 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1791 target_pid_to_str (ptid),
1792 (signo != GDB_SIGNAL_0
1793 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1795 if (target_can_async_p ())
1796 target_async (inferior_event_handler, 0);
1799 /* Send a signal to an LWP. */
1802 kill_lwp (int lwpid, int signo)
1804 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1805 fails, then we are not using nptl threads and we should be using kill. */
1807 #ifdef HAVE_TKILL_SYSCALL
1809 static int tkill_failed;
1816 ret = syscall (__NR_tkill, lwpid, signo);
1817 if (errno != ENOSYS)
1824 return kill (lwpid, signo);
1827 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1828 event, check if the core is interested in it: if not, ignore the
1829 event, and keep waiting; otherwise, we need to toggle the LWP's
1830 syscall entry/exit status, since the ptrace event itself doesn't
1831 indicate it, and report the trap to higher layers. */
1834 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1836 struct target_waitstatus *ourstatus = &lp->waitstatus;
1837 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1838 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1842 /* If we're stopping threads, there's a SIGSTOP pending, which
1843 makes it so that the LWP reports an immediate syscall return,
1844 followed by the SIGSTOP. Skip seeing that "return" using
1845 PTRACE_CONT directly, and let stop_wait_callback collect the
1846 SIGSTOP. Later when the thread is resumed, a new syscall
1847 entry event. If we didn't do this (and returned 0), we'd
1848 leave a syscall entry pending, and our caller, by using
1849 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1850 itself. Later, when the user re-resumes this LWP, we'd see
1851 another syscall entry event and we'd mistake it for a return.
1853 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1854 (leaving immediately with LWP->signalled set, without issuing
1855 a PTRACE_CONT), it would still be problematic to leave this
1856 syscall enter pending, as later when the thread is resumed,
1857 it would then see the same syscall exit mentioned above,
1858 followed by the delayed SIGSTOP, while the syscall didn't
1859 actually get to execute. It seems it would be even more
1860 confusing to the user. */
1862 if (debug_linux_nat)
1863 fprintf_unfiltered (gdb_stdlog,
1864 "LHST: ignoring syscall %d "
1865 "for LWP %ld (stopping threads), "
1866 "resuming with PTRACE_CONT for SIGSTOP\n",
1868 ptid_get_lwp (lp->ptid));
1870 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1871 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1875 if (catch_syscall_enabled ())
1877 /* Always update the entry/return state, even if this particular
1878 syscall isn't interesting to the core now. In async mode,
1879 the user could install a new catchpoint for this syscall
1880 between syscall enter/return, and we'll need to know to
1881 report a syscall return if that happens. */
1882 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1883 ? TARGET_WAITKIND_SYSCALL_RETURN
1884 : TARGET_WAITKIND_SYSCALL_ENTRY);
1886 if (catching_syscall_number (syscall_number))
1888 /* Alright, an event to report. */
1889 ourstatus->kind = lp->syscall_state;
1890 ourstatus->value.syscall_number = syscall_number;
1892 if (debug_linux_nat)
1893 fprintf_unfiltered (gdb_stdlog,
1894 "LHST: stopping for %s of syscall %d"
1897 == TARGET_WAITKIND_SYSCALL_ENTRY
1898 ? "entry" : "return",
1900 ptid_get_lwp (lp->ptid));
1904 if (debug_linux_nat)
1905 fprintf_unfiltered (gdb_stdlog,
1906 "LHST: ignoring %s of syscall %d "
1908 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1909 ? "entry" : "return",
1911 ptid_get_lwp (lp->ptid));
1915 /* If we had been syscall tracing, and hence used PT_SYSCALL
1916 before on this LWP, it could happen that the user removes all
1917 syscall catchpoints before we get to process this event.
1918 There are two noteworthy issues here:
1920 - When stopped at a syscall entry event, resuming with
1921 PT_STEP still resumes executing the syscall and reports a
1924 - Only PT_SYSCALL catches syscall enters. If we last
1925 single-stepped this thread, then this event can't be a
1926 syscall enter. If we last single-stepped this thread, this
1927 has to be a syscall exit.
1929 The points above mean that the next resume, be it PT_STEP or
1930 PT_CONTINUE, can not trigger a syscall trace event. */
1931 if (debug_linux_nat)
1932 fprintf_unfiltered (gdb_stdlog,
1933 "LHST: caught syscall event "
1934 "with no syscall catchpoints."
1935 " %d for LWP %ld, ignoring\n",
1937 ptid_get_lwp (lp->ptid));
1938 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1941 /* The core isn't interested in this event. For efficiency, avoid
1942 stopping all threads only to have the core resume them all again.
1943 Since we're not stopping threads, if we're still syscall tracing
1944 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1945 subsequent syscall. Simply resume using the inf-ptrace layer,
1946 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1948 /* Note that gdbarch_get_syscall_number may access registers, hence
1950 registers_changed ();
1951 if (linux_nat_prepare_to_resume != NULL)
1952 linux_nat_prepare_to_resume (lp);
1953 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
1954 lp->step, GDB_SIGNAL_0);
1958 /* Handle a GNU/Linux extended wait response. If we see a clone
1959 event, we need to add the new LWP to our list (and not report the
1960 trap to higher layers). This function returns non-zero if the
1961 event should be ignored and we should wait again. If STOPPING is
1962 true, the new LWP remains stopped, otherwise it is continued. */
1965 linux_handle_extended_wait (struct lwp_info *lp, int status,
1968 int pid = ptid_get_lwp (lp->ptid);
1969 struct target_waitstatus *ourstatus = &lp->waitstatus;
1970 int event = status >> 16;
1972 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1973 || event == PTRACE_EVENT_CLONE)
1975 unsigned long new_pid;
1978 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
1980 /* If we haven't already seen the new PID stop, wait for it now. */
1981 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
1983 /* The new child has a pending SIGSTOP. We can't affect it until it
1984 hits the SIGSTOP, but we're already attached. */
1985 ret = my_waitpid (new_pid, &status,
1986 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
1988 perror_with_name (_("waiting for new child"));
1989 else if (ret != new_pid)
1990 internal_error (__FILE__, __LINE__,
1991 _("wait returned unexpected PID %d"), ret);
1992 else if (!WIFSTOPPED (status))
1993 internal_error (__FILE__, __LINE__,
1994 _("wait returned unexpected status 0x%x"), status);
1997 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
1999 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
2001 /* The arch-specific native code may need to know about new
2002 forks even if those end up never mapped to an
2004 if (linux_nat_new_fork != NULL)
2005 linux_nat_new_fork (lp, new_pid);
2008 if (event == PTRACE_EVENT_FORK
2009 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
2011 /* Handle checkpointing by linux-fork.c here as a special
2012 case. We don't want the follow-fork-mode or 'catch fork'
2013 to interfere with this. */
2015 /* This won't actually modify the breakpoint list, but will
2016 physically remove the breakpoints from the child. */
2017 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
2019 /* Retain child fork in ptrace (stopped) state. */
2020 if (!find_fork_pid (new_pid))
2023 /* Report as spurious, so that infrun doesn't want to follow
2024 this fork. We're actually doing an infcall in
2026 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
2028 /* Report the stop to the core. */
2032 if (event == PTRACE_EVENT_FORK)
2033 ourstatus->kind = TARGET_WAITKIND_FORKED;
2034 else if (event == PTRACE_EVENT_VFORK)
2035 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2038 struct lwp_info *new_lp;
2040 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2042 if (debug_linux_nat)
2043 fprintf_unfiltered (gdb_stdlog,
2044 "LHEW: Got clone event "
2045 "from LWP %d, new child is LWP %ld\n",
2048 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
2050 new_lp->stopped = 1;
2052 if (WSTOPSIG (status) != SIGSTOP)
2054 /* This can happen if someone starts sending signals to
2055 the new thread before it gets a chance to run, which
2056 have a lower number than SIGSTOP (e.g. SIGUSR1).
2057 This is an unlikely case, and harder to handle for
2058 fork / vfork than for clone, so we do not try - but
2059 we handle it for clone events here. We'll send
2060 the other signal on to the thread below. */
2062 new_lp->signalled = 1;
2066 struct thread_info *tp;
2068 /* When we stop for an event in some other thread, and
2069 pull the thread list just as this thread has cloned,
2070 we'll have seen the new thread in the thread_db list
2071 before handling the CLONE event (glibc's
2072 pthread_create adds the new thread to the thread list
2073 before clone'ing, and has the kernel fill in the
2074 thread's tid on the clone call with
2075 CLONE_PARENT_SETTID). If that happened, and the core
2076 had requested the new thread to stop, we'll have
2077 killed it with SIGSTOP. But since SIGSTOP is not an
2078 RT signal, it can only be queued once. We need to be
2079 careful to not resume the LWP if we wanted it to
2080 stop. In that case, we'll leave the SIGSTOP pending.
2081 It will later be reported as GDB_SIGNAL_0. */
2082 tp = find_thread_ptid (new_lp->ptid);
2083 if (tp != NULL && tp->stop_requested)
2084 new_lp->last_resume_kind = resume_stop;
2091 /* Add the new thread to GDB's lists as soon as possible
2094 1) the frontend doesn't have to wait for a stop to
2097 2) we tag it with the correct running state. */
2099 /* If the thread_db layer is active, let it know about
2100 this new thread, and add it to GDB's list. */
2101 if (!thread_db_attach_lwp (new_lp->ptid))
2103 /* We're not using thread_db. Add it to GDB's
2105 target_post_attach (ptid_get_lwp (new_lp->ptid));
2106 add_thread (new_lp->ptid);
2111 set_running (new_lp->ptid, 1);
2112 set_executing (new_lp->ptid, 1);
2113 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2115 new_lp->last_resume_kind = resume_continue;
2121 /* We created NEW_LP so it cannot yet contain STATUS. */
2122 gdb_assert (new_lp->status == 0);
2124 /* Save the wait status to report later. */
2125 if (debug_linux_nat)
2126 fprintf_unfiltered (gdb_stdlog,
2127 "LHEW: waitpid of new LWP %ld, "
2128 "saving status %s\n",
2129 (long) ptid_get_lwp (new_lp->ptid),
2130 status_to_str (status));
2131 new_lp->status = status;
2134 /* Note the need to use the low target ops to resume, to
2135 handle resuming with PT_SYSCALL if we have syscall
2139 new_lp->resumed = 1;
2143 gdb_assert (new_lp->last_resume_kind == resume_continue);
2144 if (debug_linux_nat)
2145 fprintf_unfiltered (gdb_stdlog,
2146 "LHEW: resuming new LWP %ld\n",
2147 ptid_get_lwp (new_lp->ptid));
2148 if (linux_nat_prepare_to_resume != NULL)
2149 linux_nat_prepare_to_resume (new_lp);
2150 linux_ops->to_resume (linux_ops, pid_to_ptid (new_pid),
2152 new_lp->stopped = 0;
2156 if (debug_linux_nat)
2157 fprintf_unfiltered (gdb_stdlog,
2158 "LHEW: resuming parent LWP %d\n", pid);
2159 if (linux_nat_prepare_to_resume != NULL)
2160 linux_nat_prepare_to_resume (lp);
2161 linux_ops->to_resume (linux_ops,
2162 pid_to_ptid (ptid_get_lwp (lp->ptid)),
2171 if (event == PTRACE_EVENT_EXEC)
2173 if (debug_linux_nat)
2174 fprintf_unfiltered (gdb_stdlog,
2175 "LHEW: Got exec event from LWP %ld\n",
2176 ptid_get_lwp (lp->ptid));
2178 ourstatus->kind = TARGET_WAITKIND_EXECD;
2179 ourstatus->value.execd_pathname
2180 = xstrdup (linux_child_pid_to_exec_file (NULL, pid));
2185 if (event == PTRACE_EVENT_VFORK_DONE)
2187 if (current_inferior ()->waiting_for_vfork_done)
2189 if (debug_linux_nat)
2190 fprintf_unfiltered (gdb_stdlog,
2191 "LHEW: Got expected PTRACE_EVENT_"
2192 "VFORK_DONE from LWP %ld: stopping\n",
2193 ptid_get_lwp (lp->ptid));
2195 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2199 if (debug_linux_nat)
2200 fprintf_unfiltered (gdb_stdlog,
2201 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2202 "from LWP %ld: resuming\n",
2203 ptid_get_lwp (lp->ptid));
2204 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2208 internal_error (__FILE__, __LINE__,
2209 _("unknown ptrace event %d"), event);
2212 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2216 wait_lwp (struct lwp_info *lp)
2220 int thread_dead = 0;
2223 gdb_assert (!lp->stopped);
2224 gdb_assert (lp->status == 0);
2226 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2227 block_child_signals (&prev_mask);
2231 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2232 was right and we should just call sigsuspend. */
2234 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2235 if (pid == -1 && errno == ECHILD)
2236 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2237 if (pid == -1 && errno == ECHILD)
2239 /* The thread has previously exited. We need to delete it
2240 now because, for some vendor 2.4 kernels with NPTL
2241 support backported, there won't be an exit event unless
2242 it is the main thread. 2.6 kernels will report an exit
2243 event for each thread that exits, as expected. */
2245 if (debug_linux_nat)
2246 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2247 target_pid_to_str (lp->ptid));
2252 /* Bugs 10970, 12702.
2253 Thread group leader may have exited in which case we'll lock up in
2254 waitpid if there are other threads, even if they are all zombies too.
2255 Basically, we're not supposed to use waitpid this way.
2256 __WCLONE is not applicable for the leader so we can't use that.
2257 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2258 process; it gets ESRCH both for the zombie and for running processes.
2260 As a workaround, check if we're waiting for the thread group leader and
2261 if it's a zombie, and avoid calling waitpid if it is.
2263 This is racy, what if the tgl becomes a zombie right after we check?
2264 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2265 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2267 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2268 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2271 if (debug_linux_nat)
2272 fprintf_unfiltered (gdb_stdlog,
2273 "WL: Thread group leader %s vanished.\n",
2274 target_pid_to_str (lp->ptid));
2278 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2279 get invoked despite our caller had them intentionally blocked by
2280 block_child_signals. This is sensitive only to the loop of
2281 linux_nat_wait_1 and there if we get called my_waitpid gets called
2282 again before it gets to sigsuspend so we can safely let the handlers
2283 get executed here. */
2285 sigsuspend (&suspend_mask);
2288 restore_child_signals_mask (&prev_mask);
2292 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2294 if (debug_linux_nat)
2296 fprintf_unfiltered (gdb_stdlog,
2297 "WL: waitpid %s received %s\n",
2298 target_pid_to_str (lp->ptid),
2299 status_to_str (status));
2302 /* Check if the thread has exited. */
2303 if (WIFEXITED (status) || WIFSIGNALED (status))
2306 if (debug_linux_nat)
2307 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2308 target_pid_to_str (lp->ptid));
2318 gdb_assert (WIFSTOPPED (status));
2320 /* Handle GNU/Linux's syscall SIGTRAPs. */
2321 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2323 /* No longer need the sysgood bit. The ptrace event ends up
2324 recorded in lp->waitstatus if we care for it. We can carry
2325 on handling the event like a regular SIGTRAP from here
2327 status = W_STOPCODE (SIGTRAP);
2328 if (linux_handle_syscall_trap (lp, 1))
2329 return wait_lwp (lp);
2332 /* Handle GNU/Linux's extended waitstatus for trace events. */
2333 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2335 if (debug_linux_nat)
2336 fprintf_unfiltered (gdb_stdlog,
2337 "WL: Handling extended status 0x%06x\n",
2339 if (linux_handle_extended_wait (lp, status, 1))
2340 return wait_lwp (lp);
2346 /* Send a SIGSTOP to LP. */
2349 stop_callback (struct lwp_info *lp, void *data)
2351 if (!lp->stopped && !lp->signalled)
2355 if (debug_linux_nat)
2357 fprintf_unfiltered (gdb_stdlog,
2358 "SC: kill %s **<SIGSTOP>**\n",
2359 target_pid_to_str (lp->ptid));
2362 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2363 if (debug_linux_nat)
2365 fprintf_unfiltered (gdb_stdlog,
2366 "SC: lwp kill %d %s\n",
2368 errno ? safe_strerror (errno) : "ERRNO-OK");
2372 gdb_assert (lp->status == 0);
2378 /* Request a stop on LWP. */
2381 linux_stop_lwp (struct lwp_info *lwp)
2383 stop_callback (lwp, NULL);
2386 /* Return non-zero if LWP PID has a pending SIGINT. */
2389 linux_nat_has_pending_sigint (int pid)
2391 sigset_t pending, blocked, ignored;
2393 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2395 if (sigismember (&pending, SIGINT)
2396 && !sigismember (&ignored, SIGINT))
2402 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2405 set_ignore_sigint (struct lwp_info *lp, void *data)
2407 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2408 flag to consume the next one. */
2409 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2410 && WSTOPSIG (lp->status) == SIGINT)
2413 lp->ignore_sigint = 1;
2418 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2419 This function is called after we know the LWP has stopped; if the LWP
2420 stopped before the expected SIGINT was delivered, then it will never have
2421 arrived. Also, if the signal was delivered to a shared queue and consumed
2422 by a different thread, it will never be delivered to this LWP. */
2425 maybe_clear_ignore_sigint (struct lwp_info *lp)
2427 if (!lp->ignore_sigint)
2430 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2432 if (debug_linux_nat)
2433 fprintf_unfiltered (gdb_stdlog,
2434 "MCIS: Clearing bogus flag for %s\n",
2435 target_pid_to_str (lp->ptid));
2436 lp->ignore_sigint = 0;
2440 /* Fetch the possible triggered data watchpoint info and store it in
2443 On some archs, like x86, that use debug registers to set
2444 watchpoints, it's possible that the way to know which watched
2445 address trapped, is to check the register that is used to select
2446 which address to watch. Problem is, between setting the watchpoint
2447 and reading back which data address trapped, the user may change
2448 the set of watchpoints, and, as a consequence, GDB changes the
2449 debug registers in the inferior. To avoid reading back a stale
2450 stopped-data-address when that happens, we cache in LP the fact
2451 that a watchpoint trapped, and the corresponding data address, as
2452 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2453 registers meanwhile, we have the cached data we can rely on. */
2456 save_sigtrap (struct lwp_info *lp)
2458 struct cleanup *old_chain;
2460 if (linux_ops->to_stopped_by_watchpoint == NULL)
2462 lp->stopped_by_watchpoint = 0;
2466 old_chain = save_inferior_ptid ();
2467 inferior_ptid = lp->ptid;
2469 lp->stopped_by_watchpoint = linux_ops->to_stopped_by_watchpoint (linux_ops);
2471 if (lp->stopped_by_watchpoint)
2473 if (linux_ops->to_stopped_data_address != NULL)
2474 lp->stopped_data_address_p =
2475 linux_ops->to_stopped_data_address (¤t_target,
2476 &lp->stopped_data_address);
2478 lp->stopped_data_address_p = 0;
2481 do_cleanups (old_chain);
2484 /* See save_sigtrap. */
2487 linux_nat_stopped_by_watchpoint (struct target_ops *ops)
2489 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2491 gdb_assert (lp != NULL);
2493 return lp->stopped_by_watchpoint;
2497 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2499 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2501 gdb_assert (lp != NULL);
2503 *addr_p = lp->stopped_data_address;
2505 return lp->stopped_data_address_p;
2508 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2511 sigtrap_is_event (int status)
2513 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2516 /* SIGTRAP-like events recognizer. */
2518 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
2520 /* Check for SIGTRAP-like events in LP. */
2523 linux_nat_lp_status_is_event (struct lwp_info *lp)
2525 /* We check for lp->waitstatus in addition to lp->status, because we can
2526 have pending process exits recorded in lp->status
2527 and W_EXITCODE(0,0) == 0. We should probably have an additional
2528 lp->status_p flag. */
2530 return (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE
2531 && linux_nat_status_is_event (lp->status));
2534 /* Set alternative SIGTRAP-like events recognizer. If
2535 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2539 linux_nat_set_status_is_event (struct target_ops *t,
2540 int (*status_is_event) (int status))
2542 linux_nat_status_is_event = status_is_event;
2545 /* Wait until LP is stopped. */
2548 stop_wait_callback (struct lwp_info *lp, void *data)
2550 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2552 /* If this is a vfork parent, bail out, it is not going to report
2553 any SIGSTOP until the vfork is done with. */
2554 if (inf->vfork_child != NULL)
2561 status = wait_lwp (lp);
2565 if (lp->ignore_sigint && WIFSTOPPED (status)
2566 && WSTOPSIG (status) == SIGINT)
2568 lp->ignore_sigint = 0;
2571 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2572 if (debug_linux_nat)
2573 fprintf_unfiltered (gdb_stdlog,
2574 "PTRACE_CONT %s, 0, 0 (%s) "
2575 "(discarding SIGINT)\n",
2576 target_pid_to_str (lp->ptid),
2577 errno ? safe_strerror (errno) : "OK");
2579 return stop_wait_callback (lp, NULL);
2582 maybe_clear_ignore_sigint (lp);
2584 if (WSTOPSIG (status) != SIGSTOP)
2586 /* The thread was stopped with a signal other than SIGSTOP. */
2590 if (debug_linux_nat)
2591 fprintf_unfiltered (gdb_stdlog,
2592 "SWC: Pending event %s in %s\n",
2593 status_to_str ((int) status),
2594 target_pid_to_str (lp->ptid));
2596 /* Save the sigtrap event. */
2597 lp->status = status;
2598 gdb_assert (!lp->stopped);
2599 gdb_assert (lp->signalled);
2604 /* We caught the SIGSTOP that we intended to catch, so
2605 there's no SIGSTOP pending. */
2607 if (debug_linux_nat)
2608 fprintf_unfiltered (gdb_stdlog,
2609 "SWC: Delayed SIGSTOP caught for %s.\n",
2610 target_pid_to_str (lp->ptid));
2614 /* Reset SIGNALLED only after the stop_wait_callback call
2615 above as it does gdb_assert on SIGNALLED. */
2623 /* Return non-zero if LP has a wait status pending. */
2626 status_callback (struct lwp_info *lp, void *data)
2628 /* Only report a pending wait status if we pretend that this has
2629 indeed been resumed. */
2633 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2635 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2636 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2637 0', so a clean process exit can not be stored pending in
2638 lp->status, it is indistinguishable from
2639 no-pending-status. */
2643 if (lp->status != 0)
2649 /* Return non-zero if LP isn't stopped. */
2652 running_callback (struct lwp_info *lp, void *data)
2654 return (!lp->stopped
2655 || ((lp->status != 0
2656 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2660 /* Count the LWP's that have had events. */
2663 count_events_callback (struct lwp_info *lp, void *data)
2667 gdb_assert (count != NULL);
2669 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2670 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2676 /* Select the LWP (if any) that is currently being single-stepped. */
2679 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2681 if (lp->last_resume_kind == resume_step
2688 /* Select the Nth LWP that has had a SIGTRAP event. */
2691 select_event_lwp_callback (struct lwp_info *lp, void *data)
2693 int *selector = data;
2695 gdb_assert (selector != NULL);
2697 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2698 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2699 if ((*selector)-- == 0)
2706 cancel_breakpoint (struct lwp_info *lp)
2708 /* Arrange for a breakpoint to be hit again later. We don't keep
2709 the SIGTRAP status and don't forward the SIGTRAP signal to the
2710 LWP. We will handle the current event, eventually we will resume
2711 this LWP, and this breakpoint will trap again.
2713 If we do not do this, then we run the risk that the user will
2714 delete or disable the breakpoint, but the LWP will have already
2717 struct regcache *regcache = get_thread_regcache (lp->ptid);
2718 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2721 pc = regcache_read_pc (regcache) - target_decr_pc_after_break (gdbarch);
2722 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2724 if (debug_linux_nat)
2725 fprintf_unfiltered (gdb_stdlog,
2726 "CB: Push back breakpoint for %s\n",
2727 target_pid_to_str (lp->ptid));
2729 /* Back up the PC if necessary. */
2730 if (target_decr_pc_after_break (gdbarch))
2731 regcache_write_pc (regcache, pc);
2739 cancel_breakpoints_callback (struct lwp_info *lp, void *data)
2741 struct lwp_info *event_lp = data;
2743 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2747 /* If a LWP other than the LWP that we're reporting an event for has
2748 hit a GDB breakpoint (as opposed to some random trap signal),
2749 then just arrange for it to hit it again later. We don't keep
2750 the SIGTRAP status and don't forward the SIGTRAP signal to the
2751 LWP. We will handle the current event, eventually we will resume
2752 all LWPs, and this one will get its breakpoint trap again.
2754 If we do not do this, then we run the risk that the user will
2755 delete or disable the breakpoint, but the LWP will have already
2758 if (linux_nat_lp_status_is_event (lp)
2759 && cancel_breakpoint (lp))
2760 /* Throw away the SIGTRAP. */
2766 /* Select one LWP out of those that have events pending. */
2769 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2772 int random_selector;
2773 struct lwp_info *event_lp;
2775 /* Record the wait status for the original LWP. */
2776 (*orig_lp)->status = *status;
2778 /* Give preference to any LWP that is being single-stepped. */
2779 event_lp = iterate_over_lwps (filter,
2780 select_singlestep_lwp_callback, NULL);
2781 if (event_lp != NULL)
2783 if (debug_linux_nat)
2784 fprintf_unfiltered (gdb_stdlog,
2785 "SEL: Select single-step %s\n",
2786 target_pid_to_str (event_lp->ptid));
2790 /* No single-stepping LWP. Select one at random, out of those
2791 which have had SIGTRAP events. */
2793 /* First see how many SIGTRAP events we have. */
2794 iterate_over_lwps (filter, count_events_callback, &num_events);
2796 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2797 random_selector = (int)
2798 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2800 if (debug_linux_nat && num_events > 1)
2801 fprintf_unfiltered (gdb_stdlog,
2802 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2803 num_events, random_selector);
2805 event_lp = iterate_over_lwps (filter,
2806 select_event_lwp_callback,
2810 if (event_lp != NULL)
2812 /* Switch the event LWP. */
2813 *orig_lp = event_lp;
2814 *status = event_lp->status;
2817 /* Flush the wait status for the event LWP. */
2818 (*orig_lp)->status = 0;
2821 /* Return non-zero if LP has been resumed. */
2824 resumed_callback (struct lwp_info *lp, void *data)
2829 /* Stop an active thread, verify it still exists, then resume it. If
2830 the thread ends up with a pending status, then it is not resumed,
2831 and *DATA (really a pointer to int), is set. */
2834 stop_and_resume_callback (struct lwp_info *lp, void *data)
2836 int *new_pending_p = data;
2840 ptid_t ptid = lp->ptid;
2842 stop_callback (lp, NULL);
2843 stop_wait_callback (lp, NULL);
2845 /* Resume if the lwp still exists, and the core wanted it
2847 lp = find_lwp_pid (ptid);
2850 if (lp->last_resume_kind == resume_stop
2853 /* The core wanted the LWP to stop. Even if it stopped
2854 cleanly (with SIGSTOP), leave the event pending. */
2855 if (debug_linux_nat)
2856 fprintf_unfiltered (gdb_stdlog,
2857 "SARC: core wanted LWP %ld stopped "
2858 "(leaving SIGSTOP pending)\n",
2859 ptid_get_lwp (lp->ptid));
2860 lp->status = W_STOPCODE (SIGSTOP);
2863 if (lp->status == 0)
2865 if (debug_linux_nat)
2866 fprintf_unfiltered (gdb_stdlog,
2867 "SARC: re-resuming LWP %ld\n",
2868 ptid_get_lwp (lp->ptid));
2869 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2873 if (debug_linux_nat)
2874 fprintf_unfiltered (gdb_stdlog,
2875 "SARC: not re-resuming LWP %ld "
2877 ptid_get_lwp (lp->ptid));
2886 /* Check if we should go on and pass this event to common code.
2887 Return the affected lwp if we are, or NULL otherwise. If we stop
2888 all lwps temporarily, we may end up with new pending events in some
2889 other lwp. In that case set *NEW_PENDING_P to true. */
2891 static struct lwp_info *
2892 linux_nat_filter_event (int lwpid, int status, int *new_pending_p)
2894 struct lwp_info *lp;
2898 lp = find_lwp_pid (pid_to_ptid (lwpid));
2900 /* Check for stop events reported by a process we didn't already
2901 know about - anything not already in our LWP list.
2903 If we're expecting to receive stopped processes after
2904 fork, vfork, and clone events, then we'll just add the
2905 new one to our list and go back to waiting for the event
2906 to be reported - the stopped process might be returned
2907 from waitpid before or after the event is.
2909 But note the case of a non-leader thread exec'ing after the
2910 leader having exited, and gone from our lists. The non-leader
2911 thread changes its tid to the tgid. */
2913 if (WIFSTOPPED (status) && lp == NULL
2914 && (WSTOPSIG (status) == SIGTRAP && status >> 16 == PTRACE_EVENT_EXEC))
2916 /* A multi-thread exec after we had seen the leader exiting. */
2917 if (debug_linux_nat)
2918 fprintf_unfiltered (gdb_stdlog,
2919 "LLW: Re-adding thread group leader LWP %d.\n",
2922 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2925 add_thread (lp->ptid);
2928 if (WIFSTOPPED (status) && !lp)
2930 add_to_pid_list (&stopped_pids, lwpid, status);
2934 /* Make sure we don't report an event for the exit of an LWP not in
2935 our list, i.e. not part of the current process. This can happen
2936 if we detach from a program we originally forked and then it
2938 if (!WIFSTOPPED (status) && !lp)
2941 /* Handle GNU/Linux's syscall SIGTRAPs. */
2942 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2944 /* No longer need the sysgood bit. The ptrace event ends up
2945 recorded in lp->waitstatus if we care for it. We can carry
2946 on handling the event like a regular SIGTRAP from here
2948 status = W_STOPCODE (SIGTRAP);
2949 if (linux_handle_syscall_trap (lp, 0))
2953 /* Handle GNU/Linux's extended waitstatus for trace events. */
2954 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2956 if (debug_linux_nat)
2957 fprintf_unfiltered (gdb_stdlog,
2958 "LLW: Handling extended status 0x%06x\n",
2960 if (linux_handle_extended_wait (lp, status, 0))
2964 if (linux_nat_status_is_event (status))
2967 /* Check if the thread has exited. */
2968 if ((WIFEXITED (status) || WIFSIGNALED (status))
2969 && num_lwps (ptid_get_pid (lp->ptid)) > 1)
2971 /* If this is the main thread, we must stop all threads and verify
2972 if they are still alive. This is because in the nptl thread model
2973 on Linux 2.4, there is no signal issued for exiting LWPs
2974 other than the main thread. We only get the main thread exit
2975 signal once all child threads have already exited. If we
2976 stop all the threads and use the stop_wait_callback to check
2977 if they have exited we can determine whether this signal
2978 should be ignored or whether it means the end of the debugged
2979 application, regardless of which threading model is being
2981 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
2984 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
2985 stop_and_resume_callback, new_pending_p);
2988 if (debug_linux_nat)
2989 fprintf_unfiltered (gdb_stdlog,
2990 "LLW: %s exited.\n",
2991 target_pid_to_str (lp->ptid));
2993 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
2995 /* If there is at least one more LWP, then the exit signal
2996 was not the end of the debugged application and should be
3003 /* Check if the current LWP has previously exited. In the nptl
3004 thread model, LWPs other than the main thread do not issue
3005 signals when they exit so we must check whenever the thread has
3006 stopped. A similar check is made in stop_wait_callback(). */
3007 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3009 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3011 if (debug_linux_nat)
3012 fprintf_unfiltered (gdb_stdlog,
3013 "LLW: %s exited.\n",
3014 target_pid_to_str (lp->ptid));
3018 /* Make sure there is at least one thread running. */
3019 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3021 /* Discard the event. */
3025 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3026 an attempt to stop an LWP. */
3028 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3030 if (debug_linux_nat)
3031 fprintf_unfiltered (gdb_stdlog,
3032 "LLW: Delayed SIGSTOP caught for %s.\n",
3033 target_pid_to_str (lp->ptid));
3037 if (lp->last_resume_kind != resume_stop)
3039 /* This is a delayed SIGSTOP. */
3041 registers_changed ();
3043 if (linux_nat_prepare_to_resume != NULL)
3044 linux_nat_prepare_to_resume (lp);
3045 linux_ops->to_resume (linux_ops,
3046 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3047 lp->step, GDB_SIGNAL_0);
3048 if (debug_linux_nat)
3049 fprintf_unfiltered (gdb_stdlog,
3050 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3052 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3053 target_pid_to_str (lp->ptid));
3056 gdb_assert (lp->resumed);
3058 /* Discard the event. */
3063 /* Make sure we don't report a SIGINT that we have already displayed
3064 for another thread. */
3065 if (lp->ignore_sigint
3066 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3068 if (debug_linux_nat)
3069 fprintf_unfiltered (gdb_stdlog,
3070 "LLW: Delayed SIGINT caught for %s.\n",
3071 target_pid_to_str (lp->ptid));
3073 /* This is a delayed SIGINT. */
3074 lp->ignore_sigint = 0;
3076 registers_changed ();
3077 if (linux_nat_prepare_to_resume != NULL)
3078 linux_nat_prepare_to_resume (lp);
3079 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3080 lp->step, GDB_SIGNAL_0);
3081 if (debug_linux_nat)
3082 fprintf_unfiltered (gdb_stdlog,
3083 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3085 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3086 target_pid_to_str (lp->ptid));
3089 gdb_assert (lp->resumed);
3091 /* Discard the event. */
3095 /* An interesting event. */
3097 lp->status = status;
3101 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3102 their exits until all other threads in the group have exited. */
3105 check_zombie_leaders (void)
3107 struct inferior *inf;
3111 struct lwp_info *leader_lp;
3116 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3117 if (leader_lp != NULL
3118 /* Check if there are other threads in the group, as we may
3119 have raced with the inferior simply exiting. */
3120 && num_lwps (inf->pid) > 1
3121 && linux_proc_pid_is_zombie (inf->pid))
3123 if (debug_linux_nat)
3124 fprintf_unfiltered (gdb_stdlog,
3125 "CZL: Thread group leader %d zombie "
3126 "(it exited, or another thread execd).\n",
3129 /* A leader zombie can mean one of two things:
3131 - It exited, and there's an exit status pending
3132 available, or only the leader exited (not the whole
3133 program). In the latter case, we can't waitpid the
3134 leader's exit status until all other threads are gone.
3136 - There are 3 or more threads in the group, and a thread
3137 other than the leader exec'd. On an exec, the Linux
3138 kernel destroys all other threads (except the execing
3139 one) in the thread group, and resets the execing thread's
3140 tid to the tgid. No exit notification is sent for the
3141 execing thread -- from the ptracer's perspective, it
3142 appears as though the execing thread just vanishes.
3143 Until we reap all other threads except the leader and the
3144 execing thread, the leader will be zombie, and the
3145 execing thread will be in `D (disc sleep)'. As soon as
3146 all other threads are reaped, the execing thread changes
3147 it's tid to the tgid, and the previous (zombie) leader
3148 vanishes, giving place to the "new" leader. We could try
3149 distinguishing the exit and exec cases, by waiting once
3150 more, and seeing if something comes out, but it doesn't
3151 sound useful. The previous leader _does_ go away, and
3152 we'll re-add the new one once we see the exec event
3153 (which is just the same as what would happen if the
3154 previous leader did exit voluntarily before some other
3157 if (debug_linux_nat)
3158 fprintf_unfiltered (gdb_stdlog,
3159 "CZL: Thread group leader %d vanished.\n",
3161 exit_lwp (leader_lp);
3167 linux_nat_wait_1 (struct target_ops *ops,
3168 ptid_t ptid, struct target_waitstatus *ourstatus,
3171 static sigset_t prev_mask;
3172 enum resume_kind last_resume_kind;
3173 struct lwp_info *lp;
3176 if (debug_linux_nat)
3177 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3179 /* The first time we get here after starting a new inferior, we may
3180 not have added it to the LWP list yet - this is the earliest
3181 moment at which we know its PID. */
3182 if (ptid_is_pid (inferior_ptid))
3184 /* Upgrade the main thread's ptid. */
3185 thread_change_ptid (inferior_ptid,
3186 ptid_build (ptid_get_pid (inferior_ptid),
3187 ptid_get_pid (inferior_ptid), 0));
3189 lp = add_initial_lwp (inferior_ptid);
3193 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3194 block_child_signals (&prev_mask);
3200 /* First check if there is a LWP with a wait status pending. */
3201 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3203 /* Any LWP in the PTID group that's been resumed will do. */
3204 lp = iterate_over_lwps (ptid, status_callback, NULL);
3207 if (debug_linux_nat && lp->status)
3208 fprintf_unfiltered (gdb_stdlog,
3209 "LLW: Using pending wait status %s for %s.\n",
3210 status_to_str (lp->status),
3211 target_pid_to_str (lp->ptid));
3214 else if (ptid_lwp_p (ptid))
3216 if (debug_linux_nat)
3217 fprintf_unfiltered (gdb_stdlog,
3218 "LLW: Waiting for specific LWP %s.\n",
3219 target_pid_to_str (ptid));
3221 /* We have a specific LWP to check. */
3222 lp = find_lwp_pid (ptid);
3225 if (debug_linux_nat && lp->status)
3226 fprintf_unfiltered (gdb_stdlog,
3227 "LLW: Using pending wait status %s for %s.\n",
3228 status_to_str (lp->status),
3229 target_pid_to_str (lp->ptid));
3231 /* We check for lp->waitstatus in addition to lp->status,
3232 because we can have pending process exits recorded in
3233 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3234 an additional lp->status_p flag. */
3235 if (lp->status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3239 if (!target_can_async_p ())
3241 /* Causes SIGINT to be passed on to the attached process. */
3245 /* But if we don't find a pending event, we'll have to wait. */
3251 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3254 - If the thread group leader exits while other threads in the
3255 thread group still exist, waitpid(TGID, ...) hangs. That
3256 waitpid won't return an exit status until the other threads
3257 in the group are reapped.
3259 - When a non-leader thread execs, that thread just vanishes
3260 without reporting an exit (so we'd hang if we waited for it
3261 explicitly in that case). The exec event is reported to
3265 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3266 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3267 lwpid = my_waitpid (-1, &status, WNOHANG);
3269 if (debug_linux_nat)
3270 fprintf_unfiltered (gdb_stdlog,
3271 "LNW: waitpid(-1, ...) returned %d, %s\n",
3272 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3276 /* If this is true, then we paused LWPs momentarily, and may
3277 now have pending events to handle. */
3280 if (debug_linux_nat)
3282 fprintf_unfiltered (gdb_stdlog,
3283 "LLW: waitpid %ld received %s\n",
3284 (long) lwpid, status_to_str (status));
3287 lp = linux_nat_filter_event (lwpid, status, &new_pending);
3289 /* STATUS is now no longer valid, use LP->STATUS instead. */
3292 if (lp && !ptid_match (lp->ptid, ptid))
3294 gdb_assert (lp->resumed);
3296 if (debug_linux_nat)
3298 "LWP %ld got an event %06x, leaving pending.\n",
3299 ptid_get_lwp (lp->ptid), lp->status);
3301 if (WIFSTOPPED (lp->status))
3303 if (WSTOPSIG (lp->status) != SIGSTOP)
3305 /* Cancel breakpoint hits. The breakpoint may
3306 be removed before we fetch events from this
3307 process to report to the core. It is best
3308 not to assume the moribund breakpoints
3309 heuristic always handles these cases --- it
3310 could be too many events go through to the
3311 core before this one is handled. All-stop
3312 always cancels breakpoint hits in all
3315 && linux_nat_lp_status_is_event (lp)
3316 && cancel_breakpoint (lp))
3318 /* Throw away the SIGTRAP. */
3321 if (debug_linux_nat)
3323 "LLW: LWP %ld hit a breakpoint while"
3324 " waiting for another process;"
3326 ptid_get_lwp (lp->ptid));
3336 else if (WIFEXITED (lp->status) || WIFSIGNALED (lp->status))
3338 if (debug_linux_nat)
3340 "Process %ld exited while stopping LWPs\n",
3341 ptid_get_lwp (lp->ptid));
3343 /* This was the last lwp in the process. Since
3344 events are serialized to GDB core, and we can't
3345 report this one right now, but GDB core and the
3346 other target layers will want to be notified
3347 about the exit code/signal, leave the status
3348 pending for the next time we're able to report
3351 /* Prevent trying to stop this thread again. We'll
3352 never try to resume it because it has a pending
3356 /* Dead LWP's aren't expected to reported a pending
3360 /* Store the pending event in the waitstatus as
3361 well, because W_EXITCODE(0,0) == 0. */
3362 store_waitstatus (&lp->waitstatus, lp->status);
3371 /* Some LWP now has a pending event. Go all the way
3372 back to check it. */
3378 /* We got an event to report to the core. */
3382 /* Retry until nothing comes out of waitpid. A single
3383 SIGCHLD can indicate more than one child stopped. */
3387 /* Check for zombie thread group leaders. Those can't be reaped
3388 until all other threads in the thread group are. */
3389 check_zombie_leaders ();
3391 /* If there are no resumed children left, bail. We'd be stuck
3392 forever in the sigsuspend call below otherwise. */
3393 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3395 if (debug_linux_nat)
3396 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3398 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3400 if (!target_can_async_p ())
3401 clear_sigint_trap ();
3403 restore_child_signals_mask (&prev_mask);
3404 return minus_one_ptid;
3407 /* No interesting event to report to the core. */
3409 if (target_options & TARGET_WNOHANG)
3411 if (debug_linux_nat)
3412 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3414 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3415 restore_child_signals_mask (&prev_mask);
3416 return minus_one_ptid;
3419 /* We shouldn't end up here unless we want to try again. */
3420 gdb_assert (lp == NULL);
3422 /* Block until we get an event reported with SIGCHLD. */
3423 sigsuspend (&suspend_mask);
3426 if (!target_can_async_p ())
3427 clear_sigint_trap ();
3431 status = lp->status;
3434 /* Don't report signals that GDB isn't interested in, such as
3435 signals that are neither printed nor stopped upon. Stopping all
3436 threads can be a bit time-consuming so if we want decent
3437 performance with heavily multi-threaded programs, especially when
3438 they're using a high frequency timer, we'd better avoid it if we
3441 if (WIFSTOPPED (status))
3443 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3445 /* When using hardware single-step, we need to report every signal.
3446 Otherwise, signals in pass_mask may be short-circuited. */
3448 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status)))
3450 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3451 here? It is not clear we should. GDB may not expect
3452 other threads to run. On the other hand, not resuming
3453 newly attached threads may cause an unwanted delay in
3454 getting them running. */
3455 registers_changed ();
3456 if (linux_nat_prepare_to_resume != NULL)
3457 linux_nat_prepare_to_resume (lp);
3458 linux_ops->to_resume (linux_ops,
3459 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3461 if (debug_linux_nat)
3462 fprintf_unfiltered (gdb_stdlog,
3463 "LLW: %s %s, %s (preempt 'handle')\n",
3465 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3466 target_pid_to_str (lp->ptid),
3467 (signo != GDB_SIGNAL_0
3468 ? strsignal (gdb_signal_to_host (signo))
3476 /* Only do the below in all-stop, as we currently use SIGINT
3477 to implement target_stop (see linux_nat_stop) in
3479 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3481 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3482 forwarded to the entire process group, that is, all LWPs
3483 will receive it - unless they're using CLONE_THREAD to
3484 share signals. Since we only want to report it once, we
3485 mark it as ignored for all LWPs except this one. */
3486 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)),
3487 set_ignore_sigint, NULL);
3488 lp->ignore_sigint = 0;
3491 maybe_clear_ignore_sigint (lp);
3495 /* This LWP is stopped now. */
3498 if (debug_linux_nat)
3499 fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
3500 status_to_str (status), target_pid_to_str (lp->ptid));
3504 /* Now stop all other LWP's ... */
3505 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3507 /* ... and wait until all of them have reported back that
3508 they're no longer running. */
3509 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3511 /* If we're not waiting for a specific LWP, choose an event LWP
3512 from among those that have had events. Giving equal priority
3513 to all LWPs that have had events helps prevent
3515 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3516 select_event_lwp (ptid, &lp, &status);
3518 /* Now that we've selected our final event LWP, cancel any
3519 breakpoints in other LWPs that have hit a GDB breakpoint.
3520 See the comment in cancel_breakpoints_callback to find out
3522 iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp);
3524 /* We'll need this to determine whether to report a SIGSTOP as
3525 TARGET_WAITKIND_0. Need to take a copy because
3526 resume_clear_callback clears it. */
3527 last_resume_kind = lp->last_resume_kind;
3529 /* In all-stop, from the core's perspective, all LWPs are now
3530 stopped until a new resume action is sent over. */
3531 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3536 last_resume_kind = lp->last_resume_kind;
3537 resume_clear_callback (lp, NULL);
3540 if (linux_nat_status_is_event (status))
3542 if (debug_linux_nat)
3543 fprintf_unfiltered (gdb_stdlog,
3544 "LLW: trap ptid is %s.\n",
3545 target_pid_to_str (lp->ptid));
3548 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3550 *ourstatus = lp->waitstatus;
3551 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3554 store_waitstatus (ourstatus, status);
3556 if (debug_linux_nat)
3557 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3559 restore_child_signals_mask (&prev_mask);
3561 if (last_resume_kind == resume_stop
3562 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3563 && WSTOPSIG (status) == SIGSTOP)
3565 /* A thread that has been requested to stop by GDB with
3566 target_stop, and it stopped cleanly, so report as SIG0. The
3567 use of SIGSTOP is an implementation detail. */
3568 ourstatus->value.sig = GDB_SIGNAL_0;
3571 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3572 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3575 lp->core = linux_common_core_of_thread (lp->ptid);
3580 /* Resume LWPs that are currently stopped without any pending status
3581 to report, but are resumed from the core's perspective. */
3584 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3586 ptid_t *wait_ptid_p = data;
3591 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3593 struct regcache *regcache = get_thread_regcache (lp->ptid);
3594 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3595 CORE_ADDR pc = regcache_read_pc (regcache);
3597 gdb_assert (is_executing (lp->ptid));
3599 /* Don't bother if there's a breakpoint at PC that we'd hit
3600 immediately, and we're not waiting for this LWP. */
3601 if (!ptid_match (lp->ptid, *wait_ptid_p))
3603 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3607 if (debug_linux_nat)
3608 fprintf_unfiltered (gdb_stdlog,
3609 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3610 target_pid_to_str (lp->ptid),
3611 paddress (gdbarch, pc),
3614 registers_changed ();
3615 if (linux_nat_prepare_to_resume != NULL)
3616 linux_nat_prepare_to_resume (lp);
3617 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3618 lp->step, GDB_SIGNAL_0);
3620 lp->stopped_by_watchpoint = 0;
3627 linux_nat_wait (struct target_ops *ops,
3628 ptid_t ptid, struct target_waitstatus *ourstatus,
3633 if (debug_linux_nat)
3635 char *options_string;
3637 options_string = target_options_to_string (target_options);
3638 fprintf_unfiltered (gdb_stdlog,
3639 "linux_nat_wait: [%s], [%s]\n",
3640 target_pid_to_str (ptid),
3642 xfree (options_string);
3645 /* Flush the async file first. */
3646 if (target_can_async_p ())
3647 async_file_flush ();
3649 /* Resume LWPs that are currently stopped without any pending status
3650 to report, but are resumed from the core's perspective. LWPs get
3651 in this state if we find them stopping at a time we're not
3652 interested in reporting the event (target_wait on a
3653 specific_process, for example, see linux_nat_wait_1), and
3654 meanwhile the event became uninteresting. Don't bother resuming
3655 LWPs we're not going to wait for if they'd stop immediately. */
3657 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3659 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3661 /* If we requested any event, and something came out, assume there
3662 may be more. If we requested a specific lwp or process, also
3663 assume there may be more. */
3664 if (target_can_async_p ()
3665 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3666 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3667 || !ptid_equal (ptid, minus_one_ptid)))
3670 /* Get ready for the next event. */
3671 if (target_can_async_p ())
3672 target_async (inferior_event_handler, 0);
3678 kill_callback (struct lwp_info *lp, void *data)
3680 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3683 kill (ptid_get_lwp (lp->ptid), SIGKILL);
3684 if (debug_linux_nat)
3685 fprintf_unfiltered (gdb_stdlog,
3686 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3687 target_pid_to_str (lp->ptid),
3688 errno ? safe_strerror (errno) : "OK");
3690 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3693 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3694 if (debug_linux_nat)
3695 fprintf_unfiltered (gdb_stdlog,
3696 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3697 target_pid_to_str (lp->ptid),
3698 errno ? safe_strerror (errno) : "OK");
3704 kill_wait_callback (struct lwp_info *lp, void *data)
3708 /* We must make sure that there are no pending events (delayed
3709 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3710 program doesn't interfere with any following debugging session. */
3712 /* For cloned processes we must check both with __WCLONE and
3713 without, since the exit status of a cloned process isn't reported
3719 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3720 if (pid != (pid_t) -1)
3722 if (debug_linux_nat)
3723 fprintf_unfiltered (gdb_stdlog,
3724 "KWC: wait %s received unknown.\n",
3725 target_pid_to_str (lp->ptid));
3726 /* The Linux kernel sometimes fails to kill a thread
3727 completely after PTRACE_KILL; that goes from the stop
3728 point in do_fork out to the one in
3729 get_signal_to_deliever and waits again. So kill it
3731 kill_callback (lp, NULL);
3734 while (pid == ptid_get_lwp (lp->ptid));
3736 gdb_assert (pid == -1 && errno == ECHILD);
3741 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3742 if (pid != (pid_t) -1)
3744 if (debug_linux_nat)
3745 fprintf_unfiltered (gdb_stdlog,
3746 "KWC: wait %s received unk.\n",
3747 target_pid_to_str (lp->ptid));
3748 /* See the call to kill_callback above. */
3749 kill_callback (lp, NULL);
3752 while (pid == ptid_get_lwp (lp->ptid));
3754 gdb_assert (pid == -1 && errno == ECHILD);
3759 linux_nat_kill (struct target_ops *ops)
3761 struct target_waitstatus last;
3765 /* If we're stopped while forking and we haven't followed yet,
3766 kill the other task. We need to do this first because the
3767 parent will be sleeping if this is a vfork. */
3769 get_last_target_status (&last_ptid, &last);
3771 if (last.kind == TARGET_WAITKIND_FORKED
3772 || last.kind == TARGET_WAITKIND_VFORKED)
3774 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3777 /* Let the arch-specific native code know this process is
3779 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3782 if (forks_exist_p ())
3783 linux_fork_killall ();
3786 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3788 /* Stop all threads before killing them, since ptrace requires
3789 that the thread is stopped to sucessfully PTRACE_KILL. */
3790 iterate_over_lwps (ptid, stop_callback, NULL);
3791 /* ... and wait until all of them have reported back that
3792 they're no longer running. */
3793 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3795 /* Kill all LWP's ... */
3796 iterate_over_lwps (ptid, kill_callback, NULL);
3798 /* ... and wait until we've flushed all events. */
3799 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3802 target_mourn_inferior ();
3806 linux_nat_mourn_inferior (struct target_ops *ops)
3808 int pid = ptid_get_pid (inferior_ptid);
3810 purge_lwp_list (pid);
3812 if (! forks_exist_p ())
3813 /* Normal case, no other forks available. */
3814 linux_ops->to_mourn_inferior (ops);
3816 /* Multi-fork case. The current inferior_ptid has exited, but
3817 there are other viable forks to debug. Delete the exiting
3818 one and context-switch to the first available. */
3819 linux_fork_mourn_inferior ();
3821 /* Let the arch-specific native code know this process is gone. */
3822 linux_nat_forget_process (pid);
3825 /* Convert a native/host siginfo object, into/from the siginfo in the
3826 layout of the inferiors' architecture. */
3829 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3833 if (linux_nat_siginfo_fixup != NULL)
3834 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3836 /* If there was no callback, or the callback didn't do anything,
3837 then just do a straight memcpy. */
3841 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3843 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3847 static enum target_xfer_status
3848 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3849 const char *annex, gdb_byte *readbuf,
3850 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3851 ULONGEST *xfered_len)
3855 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3857 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3858 gdb_assert (readbuf || writebuf);
3860 pid = ptid_get_lwp (inferior_ptid);
3862 pid = ptid_get_pid (inferior_ptid);
3864 if (offset > sizeof (siginfo))
3865 return TARGET_XFER_E_IO;
3868 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3870 return TARGET_XFER_E_IO;
3872 /* When GDB is built as a 64-bit application, ptrace writes into
3873 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3874 inferior with a 64-bit GDB should look the same as debugging it
3875 with a 32-bit GDB, we need to convert it. GDB core always sees
3876 the converted layout, so any read/write will have to be done
3878 siginfo_fixup (&siginfo, inf_siginfo, 0);
3880 if (offset + len > sizeof (siginfo))
3881 len = sizeof (siginfo) - offset;
3883 if (readbuf != NULL)
3884 memcpy (readbuf, inf_siginfo + offset, len);
3887 memcpy (inf_siginfo + offset, writebuf, len);
3889 /* Convert back to ptrace layout before flushing it out. */
3890 siginfo_fixup (&siginfo, inf_siginfo, 1);
3893 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3895 return TARGET_XFER_E_IO;
3899 return TARGET_XFER_OK;
3902 static enum target_xfer_status
3903 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3904 const char *annex, gdb_byte *readbuf,
3905 const gdb_byte *writebuf,
3906 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3908 struct cleanup *old_chain;
3909 enum target_xfer_status xfer;
3911 if (object == TARGET_OBJECT_SIGNAL_INFO)
3912 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3913 offset, len, xfered_len);
3915 /* The target is connected but no live inferior is selected. Pass
3916 this request down to a lower stratum (e.g., the executable
3918 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3919 return TARGET_XFER_EOF;
3921 old_chain = save_inferior_ptid ();
3923 if (ptid_lwp_p (inferior_ptid))
3924 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3926 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3927 offset, len, xfered_len);
3929 do_cleanups (old_chain);
3934 linux_thread_alive (ptid_t ptid)
3938 gdb_assert (ptid_lwp_p (ptid));
3940 /* Send signal 0 instead of anything ptrace, because ptracing a
3941 running thread errors out claiming that the thread doesn't
3943 err = kill_lwp (ptid_get_lwp (ptid), 0);
3945 if (debug_linux_nat)
3946 fprintf_unfiltered (gdb_stdlog,
3947 "LLTA: KILL(SIG0) %s (%s)\n",
3948 target_pid_to_str (ptid),
3949 err ? safe_strerror (tmp_errno) : "OK");
3958 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3960 return linux_thread_alive (ptid);
3964 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3966 static char buf[64];
3968 if (ptid_lwp_p (ptid)
3969 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
3970 || num_lwps (ptid_get_pid (ptid)) > 1))
3972 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
3976 return normal_pid_to_str (ptid);
3980 linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
3982 int pid = ptid_get_pid (thr->ptid);
3983 long lwp = ptid_get_lwp (thr->ptid);
3984 #define FORMAT "/proc/%d/task/%ld/comm"
3985 char buf[sizeof (FORMAT) + 30];
3987 char *result = NULL;
3989 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
3990 comm_file = gdb_fopen_cloexec (buf, "r");
3993 /* Not exported by the kernel, so we define it here. */
3995 static char line[COMM_LEN + 1];
3997 if (fgets (line, sizeof (line), comm_file))
3999 char *nl = strchr (line, '\n');
4016 /* Accepts an integer PID; Returns a string representing a file that
4017 can be opened to get the symbols for the child process. */
4020 linux_child_pid_to_exec_file (struct target_ops *self, int pid)
4022 static char buf[PATH_MAX];
4023 char name[PATH_MAX];
4025 xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
4026 memset (buf, 0, PATH_MAX);
4027 if (readlink (name, buf, PATH_MAX - 1) <= 0)
4033 /* Records the thread's register state for the corefile note
4037 linux_nat_collect_thread_registers (const struct regcache *regcache,
4038 ptid_t ptid, bfd *obfd,
4039 char *note_data, int *note_size,
4040 enum gdb_signal stop_signal)
4042 struct gdbarch *gdbarch = get_regcache_arch (regcache);
4043 const struct regset *regset;
4045 gdb_gregset_t gregs;
4046 gdb_fpregset_t fpregs;
4048 core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
4051 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
4053 != NULL && regset->collect_regset != NULL)
4054 regset->collect_regset (regset, regcache, -1, &gregs, sizeof (gregs));
4056 fill_gregset (regcache, &gregs, -1);
4058 note_data = (char *) elfcore_write_prstatus
4059 (obfd, note_data, note_size, ptid_get_lwp (ptid),
4060 gdb_signal_to_host (stop_signal), &gregs);
4063 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
4065 != NULL && regset->collect_regset != NULL)
4066 regset->collect_regset (regset, regcache, -1, &fpregs, sizeof (fpregs));
4068 fill_fpregset (regcache, &fpregs, -1);
4070 note_data = (char *) elfcore_write_prfpreg (obfd, note_data, note_size,
4071 &fpregs, sizeof (fpregs));
4076 /* Fills the "to_make_corefile_note" target vector. Builds the note
4077 section for a corefile, and returns it in a malloc buffer. */
4080 linux_nat_make_corefile_notes (struct target_ops *self,
4081 bfd *obfd, int *note_size)
4083 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4084 converted to gdbarch_core_regset_sections, this function can go away. */
4085 return linux_make_corefile_notes (target_gdbarch (), obfd, note_size,
4086 linux_nat_collect_thread_registers);
4089 /* Implement the to_xfer_partial interface for memory reads using the /proc
4090 filesystem. Because we can use a single read() call for /proc, this
4091 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4092 but it doesn't support writes. */
4094 static enum target_xfer_status
4095 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4096 const char *annex, gdb_byte *readbuf,
4097 const gdb_byte *writebuf,
4098 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
4104 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4107 /* Don't bother for one word. */
4108 if (len < 3 * sizeof (long))
4109 return TARGET_XFER_EOF;
4111 /* We could keep this file open and cache it - possibly one per
4112 thread. That requires some juggling, but is even faster. */
4113 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
4114 ptid_get_pid (inferior_ptid));
4115 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
4117 return TARGET_XFER_EOF;
4119 /* If pread64 is available, use it. It's faster if the kernel
4120 supports it (only one syscall), and it's 64-bit safe even on
4121 32-bit platforms (for instance, SPARC debugging a SPARC64
4124 if (pread64 (fd, readbuf, len, offset) != len)
4126 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4135 return TARGET_XFER_EOF;
4139 return TARGET_XFER_OK;
4144 /* Enumerate spufs IDs for process PID. */
4146 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
4148 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4150 LONGEST written = 0;
4153 struct dirent *entry;
4155 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4156 dir = opendir (path);
4161 while ((entry = readdir (dir)) != NULL)
4167 fd = atoi (entry->d_name);
4171 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4172 if (stat (path, &st) != 0)
4174 if (!S_ISDIR (st.st_mode))
4177 if (statfs (path, &stfs) != 0)
4179 if (stfs.f_type != SPUFS_MAGIC)
4182 if (pos >= offset && pos + 4 <= offset + len)
4184 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4194 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4195 object type, using the /proc file system. */
4197 static enum target_xfer_status
4198 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4199 const char *annex, gdb_byte *readbuf,
4200 const gdb_byte *writebuf,
4201 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4206 int pid = ptid_get_pid (inferior_ptid);
4211 return TARGET_XFER_E_IO;
4214 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4217 return TARGET_XFER_E_IO;
4219 return TARGET_XFER_EOF;
4222 *xfered_len = (ULONGEST) l;
4223 return TARGET_XFER_OK;
4228 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4229 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4231 return TARGET_XFER_E_IO;
4234 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4237 return TARGET_XFER_EOF;
4241 ret = write (fd, writebuf, (size_t) len);
4243 ret = read (fd, readbuf, (size_t) len);
4248 return TARGET_XFER_E_IO;
4250 return TARGET_XFER_EOF;
4253 *xfered_len = (ULONGEST) ret;
4254 return TARGET_XFER_OK;
4259 /* Parse LINE as a signal set and add its set bits to SIGS. */
4262 add_line_to_sigset (const char *line, sigset_t *sigs)
4264 int len = strlen (line) - 1;
4268 if (line[len] != '\n')
4269 error (_("Could not parse signal set: %s"), line);
4277 if (*p >= '0' && *p <= '9')
4279 else if (*p >= 'a' && *p <= 'f')
4280 digit = *p - 'a' + 10;
4282 error (_("Could not parse signal set: %s"), line);
4287 sigaddset (sigs, signum + 1);
4289 sigaddset (sigs, signum + 2);
4291 sigaddset (sigs, signum + 3);
4293 sigaddset (sigs, signum + 4);
4299 /* Find process PID's pending signals from /proc/pid/status and set
4303 linux_proc_pending_signals (int pid, sigset_t *pending,
4304 sigset_t *blocked, sigset_t *ignored)
4307 char buffer[PATH_MAX], fname[PATH_MAX];
4308 struct cleanup *cleanup;
4310 sigemptyset (pending);
4311 sigemptyset (blocked);
4312 sigemptyset (ignored);
4313 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4314 procfile = gdb_fopen_cloexec (fname, "r");
4315 if (procfile == NULL)
4316 error (_("Could not open %s"), fname);
4317 cleanup = make_cleanup_fclose (procfile);
4319 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4321 /* Normal queued signals are on the SigPnd line in the status
4322 file. However, 2.6 kernels also have a "shared" pending
4323 queue for delivering signals to a thread group, so check for
4326 Unfortunately some Red Hat kernels include the shared pending
4327 queue but not the ShdPnd status field. */
4329 if (strncmp (buffer, "SigPnd:\t", 8) == 0)
4330 add_line_to_sigset (buffer + 8, pending);
4331 else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
4332 add_line_to_sigset (buffer + 8, pending);
4333 else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
4334 add_line_to_sigset (buffer + 8, blocked);
4335 else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
4336 add_line_to_sigset (buffer + 8, ignored);
4339 do_cleanups (cleanup);
4342 static enum target_xfer_status
4343 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4344 const char *annex, gdb_byte *readbuf,
4345 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4346 ULONGEST *xfered_len)
4348 gdb_assert (object == TARGET_OBJECT_OSDATA);
4350 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4351 if (*xfered_len == 0)
4352 return TARGET_XFER_EOF;
4354 return TARGET_XFER_OK;
4357 static enum target_xfer_status
4358 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4359 const char *annex, gdb_byte *readbuf,
4360 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4361 ULONGEST *xfered_len)
4363 enum target_xfer_status xfer;
4365 if (object == TARGET_OBJECT_AUXV)
4366 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4367 offset, len, xfered_len);
4369 if (object == TARGET_OBJECT_OSDATA)
4370 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4371 offset, len, xfered_len);
4373 if (object == TARGET_OBJECT_SPU)
4374 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4375 offset, len, xfered_len);
4377 /* GDB calculates all the addresses in possibly larget width of the address.
4378 Address width needs to be masked before its final use - either by
4379 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4381 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4383 if (object == TARGET_OBJECT_MEMORY)
4385 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4387 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4388 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4391 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4392 offset, len, xfered_len);
4393 if (xfer != TARGET_XFER_EOF)
4396 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4397 offset, len, xfered_len);
4401 cleanup_target_stop (void *arg)
4403 ptid_t *ptid = (ptid_t *) arg;
4405 gdb_assert (arg != NULL);
4408 target_resume (*ptid, 0, GDB_SIGNAL_0);
4411 static VEC(static_tracepoint_marker_p) *
4412 linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
4415 char s[IPA_CMD_BUF_SIZE];
4416 struct cleanup *old_chain;
4417 int pid = ptid_get_pid (inferior_ptid);
4418 VEC(static_tracepoint_marker_p) *markers = NULL;
4419 struct static_tracepoint_marker *marker = NULL;
4421 ptid_t ptid = ptid_build (pid, 0, 0);
4426 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4427 s[sizeof ("qTfSTM")] = 0;
4429 agent_run_command (pid, s, strlen (s) + 1);
4431 old_chain = make_cleanup (free_current_marker, &marker);
4432 make_cleanup (cleanup_target_stop, &ptid);
4437 marker = XCNEW (struct static_tracepoint_marker);
4441 parse_static_tracepoint_marker_definition (p, &p, marker);
4443 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4445 VEC_safe_push (static_tracepoint_marker_p,
4451 release_static_tracepoint_marker (marker);
4452 memset (marker, 0, sizeof (*marker));
4455 while (*p++ == ','); /* comma-separated list */
4457 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4458 s[sizeof ("qTsSTM")] = 0;
4459 agent_run_command (pid, s, strlen (s) + 1);
4463 do_cleanups (old_chain);
4468 /* Create a prototype generic GNU/Linux target. The client can override
4469 it with local methods. */
4472 linux_target_install_ops (struct target_ops *t)
4474 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4475 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4476 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4477 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4478 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4479 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4480 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4481 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4482 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4483 t->to_post_attach = linux_child_post_attach;
4484 t->to_follow_fork = linux_child_follow_fork;
4485 t->to_make_corefile_notes = linux_nat_make_corefile_notes;
4487 super_xfer_partial = t->to_xfer_partial;
4488 t->to_xfer_partial = linux_xfer_partial;
4490 t->to_static_tracepoint_markers_by_strid
4491 = linux_child_static_tracepoint_markers_by_strid;
4497 struct target_ops *t;
4499 t = inf_ptrace_target ();
4500 linux_target_install_ops (t);
4506 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4508 struct target_ops *t;
4510 t = inf_ptrace_trad_target (register_u_offset);
4511 linux_target_install_ops (t);
4516 /* target_is_async_p implementation. */
4519 linux_nat_is_async_p (struct target_ops *ops)
4521 /* NOTE: palves 2008-03-21: We're only async when the user requests
4522 it explicitly with the "set target-async" command.
4523 Someday, linux will always be async. */
4524 return target_async_permitted;
4527 /* target_can_async_p implementation. */
4530 linux_nat_can_async_p (struct target_ops *ops)
4532 /* NOTE: palves 2008-03-21: We're only async when the user requests
4533 it explicitly with the "set target-async" command.
4534 Someday, linux will always be async. */
4535 return target_async_permitted;
4539 linux_nat_supports_non_stop (struct target_ops *self)
4544 /* True if we want to support multi-process. To be removed when GDB
4545 supports multi-exec. */
4547 int linux_multi_process = 1;
4550 linux_nat_supports_multi_process (struct target_ops *self)
4552 return linux_multi_process;
4556 linux_nat_supports_disable_randomization (struct target_ops *self)
4558 #ifdef HAVE_PERSONALITY
4565 static int async_terminal_is_ours = 1;
4567 /* target_terminal_inferior implementation. */
4570 linux_nat_terminal_inferior (struct target_ops *self)
4572 if (!target_is_async_p ())
4574 /* Async mode is disabled. */
4575 child_terminal_inferior (self);
4579 child_terminal_inferior (self);
4581 /* Calls to target_terminal_*() are meant to be idempotent. */
4582 if (!async_terminal_is_ours)
4585 delete_file_handler (input_fd);
4586 async_terminal_is_ours = 0;
4590 /* target_terminal_ours implementation. */
4593 linux_nat_terminal_ours (struct target_ops *self)
4595 if (!target_is_async_p ())
4597 /* Async mode is disabled. */
4598 child_terminal_ours (self);
4602 /* GDB should never give the terminal to the inferior if the
4603 inferior is running in the background (run&, continue&, etc.),
4604 but claiming it sure should. */
4605 child_terminal_ours (self);
4607 if (async_terminal_is_ours)
4610 clear_sigint_trap ();
4611 add_file_handler (input_fd, stdin_event_handler, 0);
4612 async_terminal_is_ours = 1;
4615 static void (*async_client_callback) (enum inferior_event_type event_type,
4617 static void *async_client_context;
4619 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4620 so we notice when any child changes state, and notify the
4621 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4622 above to wait for the arrival of a SIGCHLD. */
4625 sigchld_handler (int signo)
4627 int old_errno = errno;
4629 if (debug_linux_nat)
4630 ui_file_write_async_safe (gdb_stdlog,
4631 "sigchld\n", sizeof ("sigchld\n") - 1);
4633 if (signo == SIGCHLD
4634 && linux_nat_event_pipe[0] != -1)
4635 async_file_mark (); /* Let the event loop know that there are
4636 events to handle. */
4641 /* Callback registered with the target events file descriptor. */
4644 handle_target_event (int error, gdb_client_data client_data)
4646 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4649 /* Create/destroy the target events pipe. Returns previous state. */
4652 linux_async_pipe (int enable)
4654 int previous = (linux_nat_event_pipe[0] != -1);
4656 if (previous != enable)
4660 /* Block child signals while we create/destroy the pipe, as
4661 their handler writes to it. */
4662 block_child_signals (&prev_mask);
4666 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4667 internal_error (__FILE__, __LINE__,
4668 "creating event pipe failed.");
4670 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4671 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4675 close (linux_nat_event_pipe[0]);
4676 close (linux_nat_event_pipe[1]);
4677 linux_nat_event_pipe[0] = -1;
4678 linux_nat_event_pipe[1] = -1;
4681 restore_child_signals_mask (&prev_mask);
4687 /* target_async implementation. */
4690 linux_nat_async (struct target_ops *ops,
4691 void (*callback) (enum inferior_event_type event_type,
4695 if (callback != NULL)
4697 async_client_callback = callback;
4698 async_client_context = context;
4699 if (!linux_async_pipe (1))
4701 add_file_handler (linux_nat_event_pipe[0],
4702 handle_target_event, NULL);
4703 /* There may be pending events to handle. Tell the event loop
4710 async_client_callback = callback;
4711 async_client_context = context;
4712 delete_file_handler (linux_nat_event_pipe[0]);
4713 linux_async_pipe (0);
4718 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4722 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4726 if (debug_linux_nat)
4727 fprintf_unfiltered (gdb_stdlog,
4728 "LNSL: running -> suspending %s\n",
4729 target_pid_to_str (lwp->ptid));
4732 if (lwp->last_resume_kind == resume_stop)
4734 if (debug_linux_nat)
4735 fprintf_unfiltered (gdb_stdlog,
4736 "linux-nat: already stopping LWP %ld at "
4738 ptid_get_lwp (lwp->ptid));
4742 stop_callback (lwp, NULL);
4743 lwp->last_resume_kind = resume_stop;
4747 /* Already known to be stopped; do nothing. */
4749 if (debug_linux_nat)
4751 if (find_thread_ptid (lwp->ptid)->stop_requested)
4752 fprintf_unfiltered (gdb_stdlog,
4753 "LNSL: already stopped/stop_requested %s\n",
4754 target_pid_to_str (lwp->ptid));
4756 fprintf_unfiltered (gdb_stdlog,
4757 "LNSL: already stopped/no "
4758 "stop_requested yet %s\n",
4759 target_pid_to_str (lwp->ptid));
4766 linux_nat_stop (struct target_ops *self, ptid_t ptid)
4769 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4771 linux_ops->to_stop (linux_ops, ptid);
4775 linux_nat_close (struct target_ops *self)
4777 /* Unregister from the event loop. */
4778 if (linux_nat_is_async_p (NULL))
4779 linux_nat_async (NULL, NULL, 0);
4781 if (linux_ops->to_close)
4782 linux_ops->to_close (linux_ops);
4787 /* When requests are passed down from the linux-nat layer to the
4788 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4789 used. The address space pointer is stored in the inferior object,
4790 but the common code that is passed such ptid can't tell whether
4791 lwpid is a "main" process id or not (it assumes so). We reverse
4792 look up the "main" process id from the lwp here. */
4794 static struct address_space *
4795 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4797 struct lwp_info *lwp;
4798 struct inferior *inf;
4801 pid = ptid_get_lwp (ptid);
4802 if (ptid_get_lwp (ptid) == 0)
4804 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4806 lwp = find_lwp_pid (ptid);
4807 pid = ptid_get_pid (lwp->ptid);
4811 /* A (pid,lwpid,0) ptid. */
4812 pid = ptid_get_pid (ptid);
4815 inf = find_inferior_pid (pid);
4816 gdb_assert (inf != NULL);
4820 /* Return the cached value of the processor core for thread PTID. */
4823 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4825 struct lwp_info *info = find_lwp_pid (ptid);
4833 linux_nat_add_target (struct target_ops *t)
4835 /* Save the provided single-threaded target. We save this in a separate
4836 variable because another target we've inherited from (e.g. inf-ptrace)
4837 may have saved a pointer to T; we want to use it for the final
4838 process stratum target. */
4839 linux_ops_saved = *t;
4840 linux_ops = &linux_ops_saved;
4842 /* Override some methods for multithreading. */
4843 t->to_create_inferior = linux_nat_create_inferior;
4844 t->to_attach = linux_nat_attach;
4845 t->to_detach = linux_nat_detach;
4846 t->to_resume = linux_nat_resume;
4847 t->to_wait = linux_nat_wait;
4848 t->to_pass_signals = linux_nat_pass_signals;
4849 t->to_xfer_partial = linux_nat_xfer_partial;
4850 t->to_kill = linux_nat_kill;
4851 t->to_mourn_inferior = linux_nat_mourn_inferior;
4852 t->to_thread_alive = linux_nat_thread_alive;
4853 t->to_pid_to_str = linux_nat_pid_to_str;
4854 t->to_thread_name = linux_nat_thread_name;
4855 t->to_has_thread_control = tc_schedlock;
4856 t->to_thread_address_space = linux_nat_thread_address_space;
4857 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4858 t->to_stopped_data_address = linux_nat_stopped_data_address;
4860 t->to_can_async_p = linux_nat_can_async_p;
4861 t->to_is_async_p = linux_nat_is_async_p;
4862 t->to_supports_non_stop = linux_nat_supports_non_stop;
4863 t->to_async = linux_nat_async;
4864 t->to_terminal_inferior = linux_nat_terminal_inferior;
4865 t->to_terminal_ours = linux_nat_terminal_ours;
4867 super_close = t->to_close;
4868 t->to_close = linux_nat_close;
4870 /* Methods for non-stop support. */
4871 t->to_stop = linux_nat_stop;
4873 t->to_supports_multi_process = linux_nat_supports_multi_process;
4875 t->to_supports_disable_randomization
4876 = linux_nat_supports_disable_randomization;
4878 t->to_core_of_thread = linux_nat_core_of_thread;
4880 /* We don't change the stratum; this target will sit at
4881 process_stratum and thread_db will set at thread_stratum. This
4882 is a little strange, since this is a multi-threaded-capable
4883 target, but we want to be on the stack below thread_db, and we
4884 also want to be used for single-threaded processes. */
4889 /* Register a method to call whenever a new thread is attached. */
4891 linux_nat_set_new_thread (struct target_ops *t,
4892 void (*new_thread) (struct lwp_info *))
4894 /* Save the pointer. We only support a single registered instance
4895 of the GNU/Linux native target, so we do not need to map this to
4897 linux_nat_new_thread = new_thread;
4900 /* See declaration in linux-nat.h. */
4903 linux_nat_set_new_fork (struct target_ops *t,
4904 linux_nat_new_fork_ftype *new_fork)
4906 /* Save the pointer. */
4907 linux_nat_new_fork = new_fork;
4910 /* See declaration in linux-nat.h. */
4913 linux_nat_set_forget_process (struct target_ops *t,
4914 linux_nat_forget_process_ftype *fn)
4916 /* Save the pointer. */
4917 linux_nat_forget_process_hook = fn;
4920 /* See declaration in linux-nat.h. */
4923 linux_nat_forget_process (pid_t pid)
4925 if (linux_nat_forget_process_hook != NULL)
4926 linux_nat_forget_process_hook (pid);
4929 /* Register a method that converts a siginfo object between the layout
4930 that ptrace returns, and the layout in the architecture of the
4933 linux_nat_set_siginfo_fixup (struct target_ops *t,
4934 int (*siginfo_fixup) (siginfo_t *,
4938 /* Save the pointer. */
4939 linux_nat_siginfo_fixup = siginfo_fixup;
4942 /* Register a method to call prior to resuming a thread. */
4945 linux_nat_set_prepare_to_resume (struct target_ops *t,
4946 void (*prepare_to_resume) (struct lwp_info *))
4948 /* Save the pointer. */
4949 linux_nat_prepare_to_resume = prepare_to_resume;
4952 /* See linux-nat.h. */
4955 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4959 pid = ptid_get_lwp (ptid);
4961 pid = ptid_get_pid (ptid);
4964 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4967 memset (siginfo, 0, sizeof (*siginfo));
4973 /* Provide a prototype to silence -Wmissing-prototypes. */
4974 extern initialize_file_ftype _initialize_linux_nat;
4977 _initialize_linux_nat (void)
4979 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4980 &debug_linux_nat, _("\
4981 Set debugging of GNU/Linux lwp module."), _("\
4982 Show debugging of GNU/Linux lwp module."), _("\
4983 Enables printf debugging output."),
4985 show_debug_linux_nat,
4986 &setdebuglist, &showdebuglist);
4988 /* Save this mask as the default. */
4989 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4991 /* Install a SIGCHLD handler. */
4992 sigchld_action.sa_handler = sigchld_handler;
4993 sigemptyset (&sigchld_action.sa_mask);
4994 sigchld_action.sa_flags = SA_RESTART;
4996 /* Make it the default. */
4997 sigaction (SIGCHLD, &sigchld_action, NULL);
4999 /* Make sure we don't block SIGCHLD during a sigsuspend. */
5000 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
5001 sigdelset (&suspend_mask, SIGCHLD);
5003 sigemptyset (&blocked_mask);
5007 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5008 the GNU/Linux Threads library and therefore doesn't really belong
5011 /* Read variable NAME in the target and return its value if found.
5012 Otherwise return zero. It is assumed that the type of the variable
5016 get_signo (const char *name)
5018 struct bound_minimal_symbol ms;
5021 ms = lookup_minimal_symbol (name, NULL, NULL);
5022 if (ms.minsym == NULL)
5025 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
5026 sizeof (signo)) != 0)
5032 /* Return the set of signals used by the threads library in *SET. */
5035 lin_thread_get_thread_signals (sigset_t *set)
5037 struct sigaction action;
5038 int restart, cancel;
5040 sigemptyset (&blocked_mask);
5043 restart = get_signo ("__pthread_sig_restart");
5044 cancel = get_signo ("__pthread_sig_cancel");
5046 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5047 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5048 not provide any way for the debugger to query the signal numbers -
5049 fortunately they don't change! */
5052 restart = __SIGRTMIN;
5055 cancel = __SIGRTMIN + 1;
5057 sigaddset (set, restart);
5058 sigaddset (set, cancel);
5060 /* The GNU/Linux Threads library makes terminating threads send a
5061 special "cancel" signal instead of SIGCHLD. Make sure we catch
5062 those (to prevent them from terminating GDB itself, which is
5063 likely to be their default action) and treat them the same way as
5066 action.sa_handler = sigchld_handler;
5067 sigemptyset (&action.sa_mask);
5068 action.sa_flags = SA_RESTART;
5069 sigaction (cancel, &action, NULL);
5071 /* We block the "cancel" signal throughout this code ... */
5072 sigaddset (&blocked_mask, cancel);
5073 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
5075 /* ... except during a sigsuspend. */
5076 sigdelset (&suspend_mask, cancel);