1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2015 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"
27 #ifdef HAVE_TKILL_SYSCALL
29 #include <sys/syscall.h>
31 #include <sys/ptrace.h>
32 #include "linux-nat.h"
33 #include "nat/linux-ptrace.h"
34 #include "nat/linux-procfs.h"
35 #include "nat/linux-personality.h"
36 #include "linux-fork.h"
37 #include "gdbthread.h"
41 #include "inf-child.h"
42 #include "inf-ptrace.h"
44 #include <sys/procfs.h> /* for elf_gregset etc. */
45 #include "elf-bfd.h" /* for elfcore_write_* */
46 #include "gregset.h" /* for gregset */
47 #include "gdbcore.h" /* for get_exec_file */
48 #include <ctype.h> /* for isdigit */
49 #include <sys/stat.h> /* for struct stat */
50 #include <fcntl.h> /* for O_RDONLY */
52 #include "event-loop.h"
53 #include "event-top.h"
55 #include <sys/types.h>
57 #include "xml-support.h"
60 #include "nat/linux-osdata.h"
61 #include "linux-tdep.h"
64 #include "tracepoint.h"
66 #include "target-descriptions.h"
67 #include "filestuff.h"
71 #define SPUFS_MAGIC 0x23c9b64e
74 /* This comment documents high-level logic of this file.
76 Waiting for events in sync mode
77 ===============================
79 When waiting for an event in a specific thread, we just use waitpid, passing
80 the specific pid, and not passing WNOHANG.
82 When waiting for an event in all threads, waitpid is not quite good. Prior to
83 version 2.4, Linux can either wait for event in main thread, or in secondary
84 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
85 miss an event. The solution is to use non-blocking waitpid, together with
86 sigsuspend. First, we use non-blocking waitpid to get an event in the main
87 process, if any. Second, we use non-blocking waitpid with the __WCLONED
88 flag to check for events in cloned processes. If nothing is found, we use
89 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
90 happened to a child process -- and SIGCHLD will be delivered both for events
91 in main debugged process and in cloned processes. As soon as we know there's
92 an event, we get back to calling nonblocking waitpid with and without
95 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
96 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
97 blocked, the signal becomes pending and sigsuspend immediately
98 notices it and returns.
100 Waiting for events in async mode
101 ================================
103 In async mode, GDB should always be ready to handle both user input
104 and target events, so neither blocking waitpid nor sigsuspend are
105 viable options. Instead, we should asynchronously notify the GDB main
106 event loop whenever there's an unprocessed event from the target. We
107 detect asynchronous target events by handling SIGCHLD signals. To
108 notify the event loop about target events, the self-pipe trick is used
109 --- a pipe is registered as waitable event source in the event loop,
110 the event loop select/poll's on the read end of this pipe (as well on
111 other event sources, e.g., stdin), and the SIGCHLD handler writes a
112 byte to this pipe. This is more portable than relying on
113 pselect/ppoll, since on kernels that lack those syscalls, libc
114 emulates them with select/poll+sigprocmask, and that is racy
115 (a.k.a. plain broken).
117 Obviously, if we fail to notify the event loop if there's a target
118 event, it's bad. OTOH, if we notify the event loop when there's no
119 event from the target, linux_nat_wait will detect that there's no real
120 event to report, and return event of type TARGET_WAITKIND_IGNORE.
121 This is mostly harmless, but it will waste time and is better avoided.
123 The main design point is that every time GDB is outside linux-nat.c,
124 we have a SIGCHLD handler installed that is called when something
125 happens to the target and notifies the GDB event loop. Whenever GDB
126 core decides to handle the event, and calls into linux-nat.c, we
127 process things as in sync mode, except that the we never block in
130 While processing an event, we may end up momentarily blocked in
131 waitpid calls. Those waitpid calls, while blocking, are guarantied to
132 return quickly. E.g., in all-stop mode, before reporting to the core
133 that an LWP hit a breakpoint, all LWPs are stopped by sending them
134 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
135 Note that this is different from blocking indefinitely waiting for the
136 next event --- here, we're already handling an event.
141 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
142 signal is not entirely significant; we just need for a signal to be delivered,
143 so that we can intercept it. SIGSTOP's advantage is that it can not be
144 blocked. A disadvantage is that it is not a real-time signal, so it can only
145 be queued once; we do not keep track of other sources of SIGSTOP.
147 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
148 use them, because they have special behavior when the signal is generated -
149 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
150 kills the entire thread group.
152 A delivered SIGSTOP would stop the entire thread group, not just the thread we
153 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
154 cancel it (by PTRACE_CONT without passing SIGSTOP).
156 We could use a real-time signal instead. This would solve those problems; we
157 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
158 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
159 generates it, and there are races with trying to find a signal that is not
163 #define O_LARGEFILE 0
166 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
167 the use of the multi-threaded target. */
168 static struct target_ops *linux_ops;
169 static struct target_ops linux_ops_saved;
171 /* The method to call, if any, when a new thread is attached. */
172 static void (*linux_nat_new_thread) (struct lwp_info *);
174 /* The method to call, if any, when a new fork is attached. */
175 static linux_nat_new_fork_ftype *linux_nat_new_fork;
177 /* The method to call, if any, when a process is no longer
179 static linux_nat_forget_process_ftype *linux_nat_forget_process_hook;
181 /* Hook to call prior to resuming a thread. */
182 static void (*linux_nat_prepare_to_resume) (struct lwp_info *);
184 /* The method to call, if any, when the siginfo object needs to be
185 converted between the layout returned by ptrace, and the layout in
186 the architecture of the inferior. */
187 static int (*linux_nat_siginfo_fixup) (siginfo_t *,
191 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
192 Called by our to_xfer_partial. */
193 static target_xfer_partial_ftype *super_xfer_partial;
195 /* The saved to_close method, inherited from inf-ptrace.c.
196 Called by our to_close. */
197 static void (*super_close) (struct target_ops *);
199 static unsigned int debug_linux_nat;
201 show_debug_linux_nat (struct ui_file *file, int from_tty,
202 struct cmd_list_element *c, const char *value)
204 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
208 struct simple_pid_list
212 struct simple_pid_list *next;
214 struct simple_pid_list *stopped_pids;
216 /* Async mode support. */
218 /* The read/write ends of the pipe registered as waitable file in the
220 static int linux_nat_event_pipe[2] = { -1, -1 };
222 /* True if we're currently in async mode. */
223 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
225 /* Flush the event pipe. */
228 async_file_flush (void)
235 ret = read (linux_nat_event_pipe[0], &buf, 1);
237 while (ret >= 0 || (ret == -1 && errno == EINTR));
240 /* Put something (anything, doesn't matter what, or how much) in event
241 pipe, so that the select/poll in the event-loop realizes we have
242 something to process. */
245 async_file_mark (void)
249 /* It doesn't really matter what the pipe contains, as long we end
250 up with something in it. Might as well flush the previous
256 ret = write (linux_nat_event_pipe[1], "+", 1);
258 while (ret == -1 && errno == EINTR);
260 /* Ignore EAGAIN. If the pipe is full, the event loop will already
261 be awakened anyway. */
264 static int kill_lwp (int lwpid, int signo);
266 static int stop_callback (struct lwp_info *lp, void *data);
267 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
269 static void block_child_signals (sigset_t *prev_mask);
270 static void restore_child_signals_mask (sigset_t *prev_mask);
273 static struct lwp_info *add_lwp (ptid_t ptid);
274 static void purge_lwp_list (int pid);
275 static void delete_lwp (ptid_t ptid);
276 static struct lwp_info *find_lwp_pid (ptid_t ptid);
278 static int lwp_status_pending_p (struct lwp_info *lp);
280 static int check_stopped_by_breakpoint (struct lwp_info *lp);
281 static int sigtrap_is_event (int status);
282 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
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
330 ATTACHED should be nonzero iff we attached to the inferior. */
333 linux_init_ptrace (pid_t pid, int attached)
335 linux_enable_event_reporting (pid, attached);
336 linux_ptrace_init_warnings ();
340 linux_child_post_attach (struct target_ops *self, int pid)
342 linux_init_ptrace (pid, 1);
346 linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
348 linux_init_ptrace (ptid_get_pid (ptid), 0);
351 /* Return the number of known LWPs in the tgid given by PID. */
359 for (lp = lwp_list; lp; lp = lp->next)
360 if (ptid_get_pid (lp->ptid) == pid)
366 /* Call delete_lwp with prototype compatible for make_cleanup. */
369 delete_lwp_cleanup (void *lp_voidp)
371 struct lwp_info *lp = lp_voidp;
373 delete_lwp (lp->ptid);
376 /* Target hook for follow_fork. On entry inferior_ptid must be the
377 ptid of the followed inferior. At return, inferior_ptid will be
381 linux_child_follow_fork (struct target_ops *ops, int follow_child,
386 struct lwp_info *child_lp = NULL;
387 int status = W_STOPCODE (0);
388 struct cleanup *old_chain;
390 ptid_t parent_ptid, child_ptid;
391 int parent_pid, child_pid;
393 has_vforked = (inferior_thread ()->pending_follow.kind
394 == TARGET_WAITKIND_VFORKED);
395 parent_ptid = inferior_ptid;
396 child_ptid = inferior_thread ()->pending_follow.value.related_pid;
397 parent_pid = ptid_get_lwp (parent_ptid);
398 child_pid = ptid_get_lwp (child_ptid);
400 /* We're already attached to the parent, by default. */
401 old_chain = save_inferior_ptid ();
402 inferior_ptid = child_ptid;
403 child_lp = add_lwp (inferior_ptid);
404 child_lp->stopped = 1;
405 child_lp->last_resume_kind = resume_stop;
407 /* Detach new forked process? */
410 make_cleanup (delete_lwp_cleanup, child_lp);
412 if (linux_nat_prepare_to_resume != NULL)
413 linux_nat_prepare_to_resume (child_lp);
415 /* When debugging an inferior in an architecture that supports
416 hardware single stepping on a kernel without commit
417 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
418 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
419 set if the parent process had them set.
420 To work around this, single step the child process
421 once before detaching to clear the flags. */
423 if (!gdbarch_software_single_step_p (target_thread_architecture
426 linux_disable_event_reporting (child_pid);
427 if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
428 perror_with_name (_("Couldn't do single step"));
429 if (my_waitpid (child_pid, &status, 0) < 0)
430 perror_with_name (_("Couldn't wait vfork process"));
433 if (WIFSTOPPED (status))
437 signo = WSTOPSIG (status);
439 && !signal_pass_state (gdb_signal_from_host (signo)))
441 ptrace (PTRACE_DETACH, child_pid, 0, signo);
444 /* Resets value of inferior_ptid to parent ptid. */
445 do_cleanups (old_chain);
449 /* Let the thread_db layer learn about this new process. */
450 check_for_thread_db ();
453 do_cleanups (old_chain);
457 struct lwp_info *parent_lp;
459 parent_lp = find_lwp_pid (parent_ptid);
460 gdb_assert (linux_supports_tracefork () >= 0);
462 if (linux_supports_tracevforkdone ())
465 fprintf_unfiltered (gdb_stdlog,
466 "LCFF: waiting for VFORK_DONE on %d\n",
468 parent_lp->stopped = 1;
470 /* We'll handle the VFORK_DONE event like any other
471 event, in target_wait. */
475 /* We can't insert breakpoints until the child has
476 finished with the shared memory region. We need to
477 wait until that happens. Ideal would be to just
479 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
480 - waitpid (parent_pid, &status, __WALL);
481 However, most architectures can't handle a syscall
482 being traced on the way out if it wasn't traced on
485 We might also think to loop, continuing the child
486 until it exits or gets a SIGTRAP. One problem is
487 that the child might call ptrace with PTRACE_TRACEME.
489 There's no simple and reliable way to figure out when
490 the vforked child will be done with its copy of the
491 shared memory. We could step it out of the syscall,
492 two instructions, let it go, and then single-step the
493 parent once. When we have hardware single-step, this
494 would work; with software single-step it could still
495 be made to work but we'd have to be able to insert
496 single-step breakpoints in the child, and we'd have
497 to insert -just- the single-step breakpoint in the
498 parent. Very awkward.
500 In the end, the best we can do is to make sure it
501 runs for a little while. Hopefully it will be out of
502 range of any breakpoints we reinsert. Usually this
503 is only the single-step breakpoint at vfork's return
507 fprintf_unfiltered (gdb_stdlog,
508 "LCFF: no VFORK_DONE "
509 "support, sleeping a bit\n");
513 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
514 and leave it pending. The next linux_nat_resume call
515 will notice a pending event, and bypasses actually
516 resuming the inferior. */
517 parent_lp->status = 0;
518 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
519 parent_lp->stopped = 1;
521 /* If we're in async mode, need to tell the event loop
522 there's something here to process. */
523 if (target_is_async_p ())
530 struct lwp_info *child_lp;
532 child_lp = add_lwp (inferior_ptid);
533 child_lp->stopped = 1;
534 child_lp->last_resume_kind = resume_stop;
536 /* Let the thread_db layer learn about this new process. */
537 check_for_thread_db ();
545 linux_child_insert_fork_catchpoint (struct target_ops *self, int pid)
547 return !linux_supports_tracefork ();
551 linux_child_remove_fork_catchpoint (struct target_ops *self, int pid)
557 linux_child_insert_vfork_catchpoint (struct target_ops *self, int pid)
559 return !linux_supports_tracefork ();
563 linux_child_remove_vfork_catchpoint (struct target_ops *self, int pid)
569 linux_child_insert_exec_catchpoint (struct target_ops *self, int pid)
571 return !linux_supports_tracefork ();
575 linux_child_remove_exec_catchpoint (struct target_ops *self, int pid)
581 linux_child_set_syscall_catchpoint (struct target_ops *self,
582 int pid, int needed, int any_count,
583 int table_size, int *table)
585 if (!linux_supports_tracesysgood ())
588 /* On GNU/Linux, we ignore the arguments. It means that we only
589 enable the syscall catchpoints, but do not disable them.
591 Also, we do not use the `table' information because we do not
592 filter system calls here. We let GDB do the logic for us. */
596 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
597 are processes sharing the same VM space. A multi-threaded process
598 is basically a group of such processes. However, such a grouping
599 is almost entirely a user-space issue; the kernel doesn't enforce
600 such a grouping at all (this might change in the future). In
601 general, we'll rely on the threads library (i.e. the GNU/Linux
602 Threads library) to provide such a grouping.
604 It is perfectly well possible to write a multi-threaded application
605 without the assistance of a threads library, by using the clone
606 system call directly. This module should be able to give some
607 rudimentary support for debugging such applications if developers
608 specify the CLONE_PTRACE flag in the clone system call, and are
609 using the Linux kernel 2.4 or above.
611 Note that there are some peculiarities in GNU/Linux that affect
614 - In general one should specify the __WCLONE flag to waitpid in
615 order to make it report events for any of the cloned processes
616 (and leave it out for the initial process). However, if a cloned
617 process has exited the exit status is only reported if the
618 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
619 we cannot use it since GDB must work on older systems too.
621 - When a traced, cloned process exits and is waited for by the
622 debugger, the kernel reassigns it to the original parent and
623 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
624 library doesn't notice this, which leads to the "zombie problem":
625 When debugged a multi-threaded process that spawns a lot of
626 threads will run out of processes, even if the threads exit,
627 because the "zombies" stay around. */
629 /* List of known LWPs. */
630 struct lwp_info *lwp_list;
633 /* Original signal mask. */
634 static sigset_t normal_mask;
636 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
637 _initialize_linux_nat. */
638 static sigset_t suspend_mask;
640 /* Signals to block to make that sigsuspend work. */
641 static sigset_t blocked_mask;
643 /* SIGCHLD action. */
644 struct sigaction sigchld_action;
646 /* Block child signals (SIGCHLD and linux threads signals), and store
647 the previous mask in PREV_MASK. */
650 block_child_signals (sigset_t *prev_mask)
652 /* Make sure SIGCHLD is blocked. */
653 if (!sigismember (&blocked_mask, SIGCHLD))
654 sigaddset (&blocked_mask, SIGCHLD);
656 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
659 /* Restore child signals mask, previously returned by
660 block_child_signals. */
663 restore_child_signals_mask (sigset_t *prev_mask)
665 sigprocmask (SIG_SETMASK, prev_mask, NULL);
668 /* Mask of signals to pass directly to the inferior. */
669 static sigset_t pass_mask;
671 /* Update signals to pass to the inferior. */
673 linux_nat_pass_signals (struct target_ops *self,
674 int numsigs, unsigned char *pass_signals)
678 sigemptyset (&pass_mask);
680 for (signo = 1; signo < NSIG; signo++)
682 int target_signo = gdb_signal_from_host (signo);
683 if (target_signo < numsigs && pass_signals[target_signo])
684 sigaddset (&pass_mask, signo);
690 /* Prototypes for local functions. */
691 static int stop_wait_callback (struct lwp_info *lp, void *data);
692 static int linux_thread_alive (ptid_t ptid);
693 static char *linux_child_pid_to_exec_file (struct target_ops *self, int pid);
694 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
698 /* Destroy and free LP. */
701 lwp_free (struct lwp_info *lp)
703 xfree (lp->arch_private);
707 /* Remove all LWPs belong to PID from the lwp list. */
710 purge_lwp_list (int pid)
712 struct lwp_info *lp, *lpprev, *lpnext;
716 for (lp = lwp_list; lp; lp = lpnext)
720 if (ptid_get_pid (lp->ptid) == pid)
725 lpprev->next = lp->next;
734 /* Add the LWP specified by PTID to the list. PTID is the first LWP
735 in the process. Return a pointer to the structure describing the
738 This differs from add_lwp in that we don't let the arch specific
739 bits know about this new thread. Current clients of this callback
740 take the opportunity to install watchpoints in the new thread, and
741 we shouldn't do that for the first thread. If we're spawning a
742 child ("run"), the thread executes the shell wrapper first, and we
743 shouldn't touch it until it execs the program we want to debug.
744 For "attach", it'd be okay to call the callback, but it's not
745 necessary, because watchpoints can't yet have been inserted into
748 static struct lwp_info *
749 add_initial_lwp (ptid_t ptid)
753 gdb_assert (ptid_lwp_p (ptid));
755 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
757 memset (lp, 0, sizeof (struct lwp_info));
759 lp->last_resume_kind = resume_continue;
760 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
771 /* Add the LWP specified by PID to the list. Return a pointer to the
772 structure describing the new LWP. The LWP should already be
775 static struct lwp_info *
776 add_lwp (ptid_t ptid)
780 lp = add_initial_lwp (ptid);
782 /* Let the arch specific bits know about this new thread. Current
783 clients of this callback take the opportunity to install
784 watchpoints in the new thread. We don't do this for the first
785 thread though. See add_initial_lwp. */
786 if (linux_nat_new_thread != NULL)
787 linux_nat_new_thread (lp);
792 /* Remove the LWP specified by PID from the list. */
795 delete_lwp (ptid_t ptid)
797 struct lwp_info *lp, *lpprev;
801 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
802 if (ptid_equal (lp->ptid, ptid))
809 lpprev->next = lp->next;
816 /* Return a pointer to the structure describing the LWP corresponding
817 to PID. If no corresponding LWP could be found, return NULL. */
819 static struct lwp_info *
820 find_lwp_pid (ptid_t ptid)
825 if (ptid_lwp_p (ptid))
826 lwp = ptid_get_lwp (ptid);
828 lwp = ptid_get_pid (ptid);
830 for (lp = lwp_list; lp; lp = lp->next)
831 if (lwp == ptid_get_lwp (lp->ptid))
837 /* Call CALLBACK with its second argument set to DATA for every LWP in
838 the list. If CALLBACK returns 1 for a particular LWP, return a
839 pointer to the structure describing that LWP immediately.
840 Otherwise return NULL. */
843 iterate_over_lwps (ptid_t filter,
844 int (*callback) (struct lwp_info *, void *),
847 struct lwp_info *lp, *lpnext;
849 for (lp = lwp_list; lp; lp = lpnext)
853 if (ptid_match (lp->ptid, filter))
855 if ((*callback) (lp, data))
863 /* Update our internal state when changing from one checkpoint to
864 another indicated by NEW_PTID. We can only switch single-threaded
865 applications, so we only create one new LWP, and the previous list
869 linux_nat_switch_fork (ptid_t new_ptid)
873 purge_lwp_list (ptid_get_pid (inferior_ptid));
875 lp = add_lwp (new_ptid);
878 /* This changes the thread's ptid while preserving the gdb thread
879 num. Also changes the inferior pid, while preserving the
881 thread_change_ptid (inferior_ptid, new_ptid);
883 /* We've just told GDB core that the thread changed target id, but,
884 in fact, it really is a different thread, with different register
886 registers_changed ();
889 /* Handle the exit of a single thread LP. */
892 exit_lwp (struct lwp_info *lp)
894 struct thread_info *th = find_thread_ptid (lp->ptid);
898 if (print_thread_events)
899 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
901 delete_thread (lp->ptid);
904 delete_lwp (lp->ptid);
907 /* Wait for the LWP specified by LP, which we have just attached to.
908 Returns a wait status for that LWP, to cache. */
911 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
914 pid_t new_pid, pid = ptid_get_lwp (ptid);
917 if (linux_proc_pid_is_stopped (pid))
920 fprintf_unfiltered (gdb_stdlog,
921 "LNPAW: Attaching to a stopped process\n");
923 /* The process is definitely stopped. It is in a job control
924 stop, unless the kernel predates the TASK_STOPPED /
925 TASK_TRACED distinction, in which case it might be in a
926 ptrace stop. Make sure it is in a ptrace stop; from there we
927 can kill it, signal it, et cetera.
929 First make sure there is a pending SIGSTOP. Since we are
930 already attached, the process can not transition from stopped
931 to running without a PTRACE_CONT; so we know this signal will
932 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
933 probably already in the queue (unless this kernel is old
934 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
935 is not an RT signal, it can only be queued once. */
936 kill_lwp (pid, SIGSTOP);
938 /* Finally, resume the stopped process. This will deliver the SIGSTOP
939 (or a higher priority signal, just like normal PTRACE_ATTACH). */
940 ptrace (PTRACE_CONT, pid, 0, 0);
943 /* Make sure the initial process is stopped. The user-level threads
944 layer might want to poke around in the inferior, and that won't
945 work if things haven't stabilized yet. */
946 new_pid = my_waitpid (pid, &status, 0);
947 if (new_pid == -1 && errno == ECHILD)
950 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
952 /* Try again with __WCLONE to check cloned processes. */
953 new_pid = my_waitpid (pid, &status, __WCLONE);
957 gdb_assert (pid == new_pid);
959 if (!WIFSTOPPED (status))
961 /* The pid we tried to attach has apparently just exited. */
963 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
964 pid, status_to_str (status));
968 if (WSTOPSIG (status) != SIGSTOP)
972 fprintf_unfiltered (gdb_stdlog,
973 "LNPAW: Received %s after attaching\n",
974 status_to_str (status));
980 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
981 the new LWP could not be attached, or 1 if we're already auto
982 attached to this thread, but haven't processed the
983 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
984 its existance, without considering it an error. */
987 lin_lwp_attach_lwp (ptid_t ptid)
992 gdb_assert (ptid_lwp_p (ptid));
994 lp = find_lwp_pid (ptid);
995 lwpid = ptid_get_lwp (ptid);
997 /* We assume that we're already attached to any LWP that is already
998 in our list of LWPs. If we're not seeing exit events from threads
999 and we've had PID wraparound since we last tried to stop all threads,
1000 this assumption might be wrong; fortunately, this is very unlikely
1004 int status, cloned = 0, signalled = 0;
1006 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1008 if (linux_supports_tracefork ())
1010 /* If we haven't stopped all threads when we get here,
1011 we may have seen a thread listed in thread_db's list,
1012 but not processed the PTRACE_EVENT_CLONE yet. If
1013 that's the case, ignore this new thread, and let
1014 normal event handling discover it later. */
1015 if (in_pid_list_p (stopped_pids, lwpid))
1017 /* We've already seen this thread stop, but we
1018 haven't seen the PTRACE_EVENT_CLONE extended
1020 if (debug_linux_nat)
1021 fprintf_unfiltered (gdb_stdlog,
1022 "LLAL: attach failed, but already seen "
1023 "this thread %s stop\n",
1024 target_pid_to_str (ptid));
1032 if (debug_linux_nat)
1033 fprintf_unfiltered (gdb_stdlog,
1034 "LLAL: attach failed, and haven't seen "
1035 "this thread %s stop yet\n",
1036 target_pid_to_str (ptid));
1038 /* We may or may not be attached to the LWP already.
1039 Try waitpid on it. If that errors, we're not
1040 attached to the LWP yet. Otherwise, we're
1041 already attached. */
1042 gdb_assert (lwpid > 0);
1043 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1044 if (new_pid == -1 && errno == ECHILD)
1045 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1050 /* The child hasn't stopped for its initial
1051 SIGSTOP stop yet. */
1052 if (debug_linux_nat)
1053 fprintf_unfiltered (gdb_stdlog,
1054 "LLAL: child hasn't "
1057 else if (WIFSTOPPED (status))
1059 if (debug_linux_nat)
1060 fprintf_unfiltered (gdb_stdlog,
1061 "LLAL: adding to stopped_pids\n");
1062 add_to_pid_list (&stopped_pids, lwpid, status);
1069 /* If we fail to attach to the thread, issue a warning,
1070 but continue. One way this can happen is if thread
1071 creation is interrupted; as of Linux kernel 2.6.19, a
1072 bug may place threads in the thread list and then fail
1074 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1075 safe_strerror (errno));
1079 if (debug_linux_nat)
1080 fprintf_unfiltered (gdb_stdlog,
1081 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1082 target_pid_to_str (ptid));
1084 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1085 if (!WIFSTOPPED (status))
1088 lp = add_lwp (ptid);
1090 lp->last_resume_kind = resume_stop;
1091 lp->cloned = cloned;
1092 lp->signalled = signalled;
1093 if (WSTOPSIG (status) != SIGSTOP)
1096 lp->status = status;
1099 target_post_attach (ptid_get_lwp (lp->ptid));
1101 if (debug_linux_nat)
1103 fprintf_unfiltered (gdb_stdlog,
1104 "LLAL: waitpid %s received %s\n",
1105 target_pid_to_str (ptid),
1106 status_to_str (status));
1114 linux_nat_create_inferior (struct target_ops *ops,
1115 char *exec_file, char *allargs, char **env,
1118 struct cleanup *restore_personality
1119 = maybe_disable_address_space_randomization (disable_randomization);
1121 /* The fork_child mechanism is synchronous and calls target_wait, so
1122 we have to mask the async mode. */
1124 /* Make sure we report all signals during startup. */
1125 linux_nat_pass_signals (ops, 0, NULL);
1127 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1129 do_cleanups (restore_personality);
1132 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1133 already attached. Returns true if a new LWP is found, false
1137 attach_proc_task_lwp_callback (ptid_t ptid)
1139 struct lwp_info *lp;
1141 /* Ignore LWPs we're already attached to. */
1142 lp = find_lwp_pid (ptid);
1145 int lwpid = ptid_get_lwp (ptid);
1147 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1151 /* Be quiet if we simply raced with the thread exiting.
1152 EPERM is returned if the thread's task still exists, and
1153 is marked as exited or zombie, as well as other
1154 conditions, so in that case, confirm the status in
1155 /proc/PID/status. */
1157 || (err == EPERM && linux_proc_pid_is_gone (lwpid)))
1159 if (debug_linux_nat)
1161 fprintf_unfiltered (gdb_stdlog,
1162 "Cannot attach to lwp %d: "
1163 "thread is gone (%d: %s)\n",
1164 lwpid, err, safe_strerror (err));
1169 warning (_("Cannot attach to lwp %d: %s"),
1171 linux_ptrace_attach_fail_reason_string (ptid,
1177 if (debug_linux_nat)
1178 fprintf_unfiltered (gdb_stdlog,
1179 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1180 target_pid_to_str (ptid));
1182 lp = add_lwp (ptid);
1185 /* The next time we wait for this LWP we'll see a SIGSTOP as
1186 PTRACE_ATTACH brings it to a halt. */
1189 /* We need to wait for a stop before being able to make the
1190 next ptrace call on this LWP. */
1191 lp->must_set_ptrace_flags = 1;
1200 linux_nat_attach (struct target_ops *ops, const char *args, int from_tty)
1202 struct lwp_info *lp;
1205 volatile struct gdb_exception ex;
1207 /* Make sure we report all signals during attach. */
1208 linux_nat_pass_signals (ops, 0, NULL);
1210 TRY_CATCH (ex, RETURN_MASK_ERROR)
1212 linux_ops->to_attach (ops, args, from_tty);
1216 pid_t pid = parse_pid_to_attach (args);
1217 struct buffer buffer;
1218 char *message, *buffer_s;
1220 message = xstrdup (ex.message);
1221 make_cleanup (xfree, message);
1223 buffer_init (&buffer);
1224 linux_ptrace_attach_fail_reason (pid, &buffer);
1226 buffer_grow_str0 (&buffer, "");
1227 buffer_s = buffer_finish (&buffer);
1228 make_cleanup (xfree, buffer_s);
1230 if (*buffer_s != '\0')
1231 throw_error (ex.error, "warning: %s\n%s", buffer_s, message);
1233 throw_error (ex.error, "%s", message);
1236 /* The ptrace base target adds the main thread with (pid,0,0)
1237 format. Decorate it with lwp info. */
1238 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1239 ptid_get_pid (inferior_ptid),
1241 thread_change_ptid (inferior_ptid, ptid);
1243 /* Add the initial process as the first LWP to the list. */
1244 lp = add_initial_lwp (ptid);
1246 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1248 if (!WIFSTOPPED (status))
1250 if (WIFEXITED (status))
1252 int exit_code = WEXITSTATUS (status);
1254 target_terminal_ours ();
1255 target_mourn_inferior ();
1257 error (_("Unable to attach: program exited normally."));
1259 error (_("Unable to attach: program exited with code %d."),
1262 else if (WIFSIGNALED (status))
1264 enum gdb_signal signo;
1266 target_terminal_ours ();
1267 target_mourn_inferior ();
1269 signo = gdb_signal_from_host (WTERMSIG (status));
1270 error (_("Unable to attach: program terminated with signal "
1272 gdb_signal_to_name (signo),
1273 gdb_signal_to_string (signo));
1276 internal_error (__FILE__, __LINE__,
1277 _("unexpected status %d for PID %ld"),
1278 status, (long) ptid_get_lwp (ptid));
1283 /* Save the wait status to report later. */
1285 if (debug_linux_nat)
1286 fprintf_unfiltered (gdb_stdlog,
1287 "LNA: waitpid %ld, saving status %s\n",
1288 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1290 lp->status = status;
1292 /* We must attach to every LWP. If /proc is mounted, use that to
1293 find them now. The inferior may be using raw clone instead of
1294 using pthreads. But even if it is using pthreads, thread_db
1295 walks structures in the inferior's address space to find the list
1296 of threads/LWPs, and those structures may well be corrupted.
1297 Note that once thread_db is loaded, we'll still use it to list
1298 threads and associate pthread info with each LWP. */
1299 linux_proc_attach_tgid_threads (ptid_get_pid (lp->ptid),
1300 attach_proc_task_lwp_callback);
1302 if (target_can_async_p ())
1303 target_async (inferior_event_handler, 0);
1306 /* Get pending status of LP. */
1308 get_pending_status (struct lwp_info *lp, int *status)
1310 enum gdb_signal signo = GDB_SIGNAL_0;
1312 /* If we paused threads momentarily, we may have stored pending
1313 events in lp->status or lp->waitstatus (see stop_wait_callback),
1314 and GDB core hasn't seen any signal for those threads.
1315 Otherwise, the last signal reported to the core is found in the
1316 thread object's stop_signal.
1318 There's a corner case that isn't handled here at present. Only
1319 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1320 stop_signal make sense as a real signal to pass to the inferior.
1321 Some catchpoint related events, like
1322 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1323 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1324 those traps are debug API (ptrace in our case) related and
1325 induced; the inferior wouldn't see them if it wasn't being
1326 traced. Hence, we should never pass them to the inferior, even
1327 when set to pass state. Since this corner case isn't handled by
1328 infrun.c when proceeding with a signal, for consistency, neither
1329 do we handle it here (or elsewhere in the file we check for
1330 signal pass state). Normally SIGTRAP isn't set to pass state, so
1331 this is really a corner case. */
1333 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1334 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1335 else if (lp->status)
1336 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1337 else if (non_stop && !is_executing (lp->ptid))
1339 struct thread_info *tp = find_thread_ptid (lp->ptid);
1341 signo = tp->suspend.stop_signal;
1345 struct target_waitstatus last;
1348 get_last_target_status (&last_ptid, &last);
1350 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1352 struct thread_info *tp = find_thread_ptid (lp->ptid);
1354 signo = tp->suspend.stop_signal;
1360 if (signo == GDB_SIGNAL_0)
1362 if (debug_linux_nat)
1363 fprintf_unfiltered (gdb_stdlog,
1364 "GPT: lwp %s has no pending signal\n",
1365 target_pid_to_str (lp->ptid));
1367 else if (!signal_pass_state (signo))
1369 if (debug_linux_nat)
1370 fprintf_unfiltered (gdb_stdlog,
1371 "GPT: lwp %s had signal %s, "
1372 "but it is in no pass state\n",
1373 target_pid_to_str (lp->ptid),
1374 gdb_signal_to_string (signo));
1378 *status = W_STOPCODE (gdb_signal_to_host (signo));
1380 if (debug_linux_nat)
1381 fprintf_unfiltered (gdb_stdlog,
1382 "GPT: lwp %s has pending signal %s\n",
1383 target_pid_to_str (lp->ptid),
1384 gdb_signal_to_string (signo));
1391 detach_callback (struct lwp_info *lp, void *data)
1393 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1395 if (debug_linux_nat && lp->status)
1396 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1397 strsignal (WSTOPSIG (lp->status)),
1398 target_pid_to_str (lp->ptid));
1400 /* If there is a pending SIGSTOP, get rid of it. */
1403 if (debug_linux_nat)
1404 fprintf_unfiltered (gdb_stdlog,
1405 "DC: Sending SIGCONT to %s\n",
1406 target_pid_to_str (lp->ptid));
1408 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1412 /* We don't actually detach from the LWP that has an id equal to the
1413 overall process id just yet. */
1414 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1418 /* Pass on any pending signal for this LWP. */
1419 get_pending_status (lp, &status);
1421 if (linux_nat_prepare_to_resume != NULL)
1422 linux_nat_prepare_to_resume (lp);
1424 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1425 WSTOPSIG (status)) < 0)
1426 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1427 safe_strerror (errno));
1429 if (debug_linux_nat)
1430 fprintf_unfiltered (gdb_stdlog,
1431 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1432 target_pid_to_str (lp->ptid),
1433 strsignal (WSTOPSIG (status)));
1435 delete_lwp (lp->ptid);
1442 linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
1446 struct lwp_info *main_lwp;
1448 pid = ptid_get_pid (inferior_ptid);
1450 /* Don't unregister from the event loop, as there may be other
1451 inferiors running. */
1453 /* Stop all threads before detaching. ptrace requires that the
1454 thread is stopped to sucessfully detach. */
1455 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1456 /* ... and wait until all of them have reported back that
1457 they're no longer running. */
1458 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1460 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1462 /* Only the initial process should be left right now. */
1463 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1465 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1467 /* Pass on any pending signal for the last LWP. */
1468 if ((args == NULL || *args == '\0')
1469 && get_pending_status (main_lwp, &status) != -1
1470 && WIFSTOPPED (status))
1474 /* Put the signal number in ARGS so that inf_ptrace_detach will
1475 pass it along with PTRACE_DETACH. */
1477 xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
1479 if (debug_linux_nat)
1480 fprintf_unfiltered (gdb_stdlog,
1481 "LND: Sending signal %s to %s\n",
1483 target_pid_to_str (main_lwp->ptid));
1486 if (linux_nat_prepare_to_resume != NULL)
1487 linux_nat_prepare_to_resume (main_lwp);
1488 delete_lwp (main_lwp->ptid);
1490 if (forks_exist_p ())
1492 /* Multi-fork case. The current inferior_ptid is being detached
1493 from, but there are other viable forks to debug. Detach from
1494 the current fork, and context-switch to the first
1496 linux_fork_detach (args, from_tty);
1499 linux_ops->to_detach (ops, args, from_tty);
1502 /* Resume execution of the inferior process. If STEP is nonzero,
1503 single-step it. If SIGNAL is nonzero, give it that signal. */
1506 linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1510 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1511 We only presently need that if the LWP is stepped though (to
1512 handle the case of stepping a breakpoint instruction). */
1515 struct regcache *regcache = get_thread_regcache (lp->ptid);
1517 lp->stop_pc = regcache_read_pc (regcache);
1522 if (linux_nat_prepare_to_resume != NULL)
1523 linux_nat_prepare_to_resume (lp);
1524 linux_ops->to_resume (linux_ops, lp->ptid, step, signo);
1525 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1527 registers_changed_ptid (lp->ptid);
1533 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1537 struct inferior *inf = find_inferior_ptid (lp->ptid);
1539 if (inf->vfork_child != NULL)
1541 if (debug_linux_nat)
1542 fprintf_unfiltered (gdb_stdlog,
1543 "RC: Not resuming %s (vfork parent)\n",
1544 target_pid_to_str (lp->ptid));
1546 else if (!lwp_status_pending_p (lp))
1548 if (debug_linux_nat)
1549 fprintf_unfiltered (gdb_stdlog,
1550 "RC: Resuming sibling %s, %s, %s\n",
1551 target_pid_to_str (lp->ptid),
1552 (signo != GDB_SIGNAL_0
1553 ? strsignal (gdb_signal_to_host (signo))
1555 step ? "step" : "resume");
1557 linux_resume_one_lwp (lp, step, signo);
1561 if (debug_linux_nat)
1562 fprintf_unfiltered (gdb_stdlog,
1563 "RC: Not resuming sibling %s (has pending)\n",
1564 target_pid_to_str (lp->ptid));
1569 if (debug_linux_nat)
1570 fprintf_unfiltered (gdb_stdlog,
1571 "RC: Not resuming sibling %s (not stopped)\n",
1572 target_pid_to_str (lp->ptid));
1576 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1577 Resume LWP with the last stop signal, if it is in pass state. */
1580 linux_nat_resume_callback (struct lwp_info *lp, void *except)
1582 enum gdb_signal signo = GDB_SIGNAL_0;
1589 struct thread_info *thread;
1591 thread = find_thread_ptid (lp->ptid);
1594 signo = thread->suspend.stop_signal;
1595 thread->suspend.stop_signal = GDB_SIGNAL_0;
1599 resume_lwp (lp, 0, signo);
1604 resume_clear_callback (struct lwp_info *lp, void *data)
1607 lp->last_resume_kind = resume_stop;
1612 resume_set_callback (struct lwp_info *lp, void *data)
1615 lp->last_resume_kind = resume_continue;
1620 linux_nat_resume (struct target_ops *ops,
1621 ptid_t ptid, int step, enum gdb_signal signo)
1623 struct lwp_info *lp;
1626 if (debug_linux_nat)
1627 fprintf_unfiltered (gdb_stdlog,
1628 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1629 step ? "step" : "resume",
1630 target_pid_to_str (ptid),
1631 (signo != GDB_SIGNAL_0
1632 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1633 target_pid_to_str (inferior_ptid));
1635 /* A specific PTID means `step only this process id'. */
1636 resume_many = (ptid_equal (minus_one_ptid, ptid)
1637 || ptid_is_pid (ptid));
1639 /* Mark the lwps we're resuming as resumed. */
1640 iterate_over_lwps (ptid, resume_set_callback, NULL);
1642 /* See if it's the current inferior that should be handled
1645 lp = find_lwp_pid (inferior_ptid);
1647 lp = find_lwp_pid (ptid);
1648 gdb_assert (lp != NULL);
1650 /* Remember if we're stepping. */
1651 lp->last_resume_kind = step ? resume_step : resume_continue;
1653 /* If we have a pending wait status for this thread, there is no
1654 point in resuming the process. But first make sure that
1655 linux_nat_wait won't preemptively handle the event - we
1656 should never take this short-circuit if we are going to
1657 leave LP running, since we have skipped resuming all the
1658 other threads. This bit of code needs to be synchronized
1659 with linux_nat_wait. */
1661 if (lp->status && WIFSTOPPED (lp->status))
1664 && WSTOPSIG (lp->status)
1665 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1667 if (debug_linux_nat)
1668 fprintf_unfiltered (gdb_stdlog,
1669 "LLR: Not short circuiting for ignored "
1670 "status 0x%x\n", lp->status);
1672 /* FIXME: What should we do if we are supposed to continue
1673 this thread with a signal? */
1674 gdb_assert (signo == GDB_SIGNAL_0);
1675 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1680 if (lwp_status_pending_p (lp))
1682 /* FIXME: What should we do if we are supposed to continue
1683 this thread with a signal? */
1684 gdb_assert (signo == GDB_SIGNAL_0);
1686 if (debug_linux_nat)
1687 fprintf_unfiltered (gdb_stdlog,
1688 "LLR: Short circuiting for status 0x%x\n",
1691 if (target_can_async_p ())
1693 target_async (inferior_event_handler, 0);
1694 /* Tell the event loop we have something to process. */
1701 iterate_over_lwps (ptid, linux_nat_resume_callback, lp);
1703 linux_resume_one_lwp (lp, step, signo);
1705 if (debug_linux_nat)
1706 fprintf_unfiltered (gdb_stdlog,
1707 "LLR: %s %s, %s (resume event thread)\n",
1708 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1709 target_pid_to_str (ptid),
1710 (signo != GDB_SIGNAL_0
1711 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1713 if (target_can_async_p ())
1714 target_async (inferior_event_handler, 0);
1717 /* Send a signal to an LWP. */
1720 kill_lwp (int lwpid, int signo)
1722 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1723 fails, then we are not using nptl threads and we should be using kill. */
1725 #ifdef HAVE_TKILL_SYSCALL
1727 static int tkill_failed;
1734 ret = syscall (__NR_tkill, lwpid, signo);
1735 if (errno != ENOSYS)
1742 return kill (lwpid, signo);
1745 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1746 event, check if the core is interested in it: if not, ignore the
1747 event, and keep waiting; otherwise, we need to toggle the LWP's
1748 syscall entry/exit status, since the ptrace event itself doesn't
1749 indicate it, and report the trap to higher layers. */
1752 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1754 struct target_waitstatus *ourstatus = &lp->waitstatus;
1755 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1756 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1760 /* If we're stopping threads, there's a SIGSTOP pending, which
1761 makes it so that the LWP reports an immediate syscall return,
1762 followed by the SIGSTOP. Skip seeing that "return" using
1763 PTRACE_CONT directly, and let stop_wait_callback collect the
1764 SIGSTOP. Later when the thread is resumed, a new syscall
1765 entry event. If we didn't do this (and returned 0), we'd
1766 leave a syscall entry pending, and our caller, by using
1767 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1768 itself. Later, when the user re-resumes this LWP, we'd see
1769 another syscall entry event and we'd mistake it for a return.
1771 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1772 (leaving immediately with LWP->signalled set, without issuing
1773 a PTRACE_CONT), it would still be problematic to leave this
1774 syscall enter pending, as later when the thread is resumed,
1775 it would then see the same syscall exit mentioned above,
1776 followed by the delayed SIGSTOP, while the syscall didn't
1777 actually get to execute. It seems it would be even more
1778 confusing to the user. */
1780 if (debug_linux_nat)
1781 fprintf_unfiltered (gdb_stdlog,
1782 "LHST: ignoring syscall %d "
1783 "for LWP %ld (stopping threads), "
1784 "resuming with PTRACE_CONT for SIGSTOP\n",
1786 ptid_get_lwp (lp->ptid));
1788 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1789 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1794 if (catch_syscall_enabled ())
1796 /* Always update the entry/return state, even if this particular
1797 syscall isn't interesting to the core now. In async mode,
1798 the user could install a new catchpoint for this syscall
1799 between syscall enter/return, and we'll need to know to
1800 report a syscall return if that happens. */
1801 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1802 ? TARGET_WAITKIND_SYSCALL_RETURN
1803 : TARGET_WAITKIND_SYSCALL_ENTRY);
1805 if (catching_syscall_number (syscall_number))
1807 /* Alright, an event to report. */
1808 ourstatus->kind = lp->syscall_state;
1809 ourstatus->value.syscall_number = syscall_number;
1811 if (debug_linux_nat)
1812 fprintf_unfiltered (gdb_stdlog,
1813 "LHST: stopping for %s of syscall %d"
1816 == TARGET_WAITKIND_SYSCALL_ENTRY
1817 ? "entry" : "return",
1819 ptid_get_lwp (lp->ptid));
1823 if (debug_linux_nat)
1824 fprintf_unfiltered (gdb_stdlog,
1825 "LHST: ignoring %s of syscall %d "
1827 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1828 ? "entry" : "return",
1830 ptid_get_lwp (lp->ptid));
1834 /* If we had been syscall tracing, and hence used PT_SYSCALL
1835 before on this LWP, it could happen that the user removes all
1836 syscall catchpoints before we get to process this event.
1837 There are two noteworthy issues here:
1839 - When stopped at a syscall entry event, resuming with
1840 PT_STEP still resumes executing the syscall and reports a
1843 - Only PT_SYSCALL catches syscall enters. If we last
1844 single-stepped this thread, then this event can't be a
1845 syscall enter. If we last single-stepped this thread, this
1846 has to be a syscall exit.
1848 The points above mean that the next resume, be it PT_STEP or
1849 PT_CONTINUE, can not trigger a syscall trace event. */
1850 if (debug_linux_nat)
1851 fprintf_unfiltered (gdb_stdlog,
1852 "LHST: caught syscall event "
1853 "with no syscall catchpoints."
1854 " %d for LWP %ld, ignoring\n",
1856 ptid_get_lwp (lp->ptid));
1857 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1860 /* The core isn't interested in this event. For efficiency, avoid
1861 stopping all threads only to have the core resume them all again.
1862 Since we're not stopping threads, if we're still syscall tracing
1863 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1864 subsequent syscall. Simply resume using the inf-ptrace layer,
1865 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1867 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
1871 /* Handle a GNU/Linux extended wait response. If we see a clone
1872 event, we need to add the new LWP to our list (and not report the
1873 trap to higher layers). This function returns non-zero if the
1874 event should be ignored and we should wait again. If STOPPING is
1875 true, the new LWP remains stopped, otherwise it is continued. */
1878 linux_handle_extended_wait (struct lwp_info *lp, int status,
1881 int pid = ptid_get_lwp (lp->ptid);
1882 struct target_waitstatus *ourstatus = &lp->waitstatus;
1883 int event = linux_ptrace_get_extended_event (status);
1885 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1886 || event == PTRACE_EVENT_CLONE)
1888 unsigned long new_pid;
1891 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
1893 /* If we haven't already seen the new PID stop, wait for it now. */
1894 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
1896 /* The new child has a pending SIGSTOP. We can't affect it until it
1897 hits the SIGSTOP, but we're already attached. */
1898 ret = my_waitpid (new_pid, &status,
1899 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
1901 perror_with_name (_("waiting for new child"));
1902 else if (ret != new_pid)
1903 internal_error (__FILE__, __LINE__,
1904 _("wait returned unexpected PID %d"), ret);
1905 else if (!WIFSTOPPED (status))
1906 internal_error (__FILE__, __LINE__,
1907 _("wait returned unexpected status 0x%x"), status);
1910 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
1912 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
1914 /* The arch-specific native code may need to know about new
1915 forks even if those end up never mapped to an
1917 if (linux_nat_new_fork != NULL)
1918 linux_nat_new_fork (lp, new_pid);
1921 if (event == PTRACE_EVENT_FORK
1922 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
1924 /* Handle checkpointing by linux-fork.c here as a special
1925 case. We don't want the follow-fork-mode or 'catch fork'
1926 to interfere with this. */
1928 /* This won't actually modify the breakpoint list, but will
1929 physically remove the breakpoints from the child. */
1930 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
1932 /* Retain child fork in ptrace (stopped) state. */
1933 if (!find_fork_pid (new_pid))
1936 /* Report as spurious, so that infrun doesn't want to follow
1937 this fork. We're actually doing an infcall in
1939 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
1941 /* Report the stop to the core. */
1945 if (event == PTRACE_EVENT_FORK)
1946 ourstatus->kind = TARGET_WAITKIND_FORKED;
1947 else if (event == PTRACE_EVENT_VFORK)
1948 ourstatus->kind = TARGET_WAITKIND_VFORKED;
1951 struct lwp_info *new_lp;
1953 ourstatus->kind = TARGET_WAITKIND_IGNORE;
1955 if (debug_linux_nat)
1956 fprintf_unfiltered (gdb_stdlog,
1957 "LHEW: Got clone event "
1958 "from LWP %d, new child is LWP %ld\n",
1961 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
1963 new_lp->stopped = 1;
1965 if (WSTOPSIG (status) != SIGSTOP)
1967 /* This can happen if someone starts sending signals to
1968 the new thread before it gets a chance to run, which
1969 have a lower number than SIGSTOP (e.g. SIGUSR1).
1970 This is an unlikely case, and harder to handle for
1971 fork / vfork than for clone, so we do not try - but
1972 we handle it for clone events here. We'll send
1973 the other signal on to the thread below. */
1975 new_lp->signalled = 1;
1979 struct thread_info *tp;
1981 /* When we stop for an event in some other thread, and
1982 pull the thread list just as this thread has cloned,
1983 we'll have seen the new thread in the thread_db list
1984 before handling the CLONE event (glibc's
1985 pthread_create adds the new thread to the thread list
1986 before clone'ing, and has the kernel fill in the
1987 thread's tid on the clone call with
1988 CLONE_PARENT_SETTID). If that happened, and the core
1989 had requested the new thread to stop, we'll have
1990 killed it with SIGSTOP. But since SIGSTOP is not an
1991 RT signal, it can only be queued once. We need to be
1992 careful to not resume the LWP if we wanted it to
1993 stop. In that case, we'll leave the SIGSTOP pending.
1994 It will later be reported as GDB_SIGNAL_0. */
1995 tp = find_thread_ptid (new_lp->ptid);
1996 if (tp != NULL && tp->stop_requested)
1997 new_lp->last_resume_kind = resume_stop;
2002 /* If the thread_db layer is active, let it record the user
2003 level thread id and status, and add the thread to GDB's
2005 if (!thread_db_notice_clone (lp->ptid, new_lp->ptid))
2007 /* The process is not using thread_db. Add the LWP to
2009 target_post_attach (ptid_get_lwp (new_lp->ptid));
2010 add_thread (new_lp->ptid);
2015 set_running (new_lp->ptid, 1);
2016 set_executing (new_lp->ptid, 1);
2017 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2019 new_lp->last_resume_kind = resume_continue;
2024 /* We created NEW_LP so it cannot yet contain STATUS. */
2025 gdb_assert (new_lp->status == 0);
2027 /* Save the wait status to report later. */
2028 if (debug_linux_nat)
2029 fprintf_unfiltered (gdb_stdlog,
2030 "LHEW: waitpid of new LWP %ld, "
2031 "saving status %s\n",
2032 (long) ptid_get_lwp (new_lp->ptid),
2033 status_to_str (status));
2034 new_lp->status = status;
2037 new_lp->resumed = !stopping;
2044 if (event == PTRACE_EVENT_EXEC)
2046 if (debug_linux_nat)
2047 fprintf_unfiltered (gdb_stdlog,
2048 "LHEW: Got exec event from LWP %ld\n",
2049 ptid_get_lwp (lp->ptid));
2051 ourstatus->kind = TARGET_WAITKIND_EXECD;
2052 ourstatus->value.execd_pathname
2053 = xstrdup (linux_child_pid_to_exec_file (NULL, pid));
2055 /* The thread that execed must have been resumed, but, when a
2056 thread execs, it changes its tid to the tgid, and the old
2057 tgid thread might have not been resumed. */
2062 if (event == PTRACE_EVENT_VFORK_DONE)
2064 if (current_inferior ()->waiting_for_vfork_done)
2066 if (debug_linux_nat)
2067 fprintf_unfiltered (gdb_stdlog,
2068 "LHEW: Got expected PTRACE_EVENT_"
2069 "VFORK_DONE from LWP %ld: stopping\n",
2070 ptid_get_lwp (lp->ptid));
2072 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2076 if (debug_linux_nat)
2077 fprintf_unfiltered (gdb_stdlog,
2078 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2079 "from LWP %ld: ignoring\n",
2080 ptid_get_lwp (lp->ptid));
2084 internal_error (__FILE__, __LINE__,
2085 _("unknown ptrace event %d"), event);
2088 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2092 wait_lwp (struct lwp_info *lp)
2096 int thread_dead = 0;
2099 gdb_assert (!lp->stopped);
2100 gdb_assert (lp->status == 0);
2102 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2103 block_child_signals (&prev_mask);
2107 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2108 was right and we should just call sigsuspend. */
2110 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2111 if (pid == -1 && errno == ECHILD)
2112 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2113 if (pid == -1 && errno == ECHILD)
2115 /* The thread has previously exited. We need to delete it
2116 now because, for some vendor 2.4 kernels with NPTL
2117 support backported, there won't be an exit event unless
2118 it is the main thread. 2.6 kernels will report an exit
2119 event for each thread that exits, as expected. */
2121 if (debug_linux_nat)
2122 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2123 target_pid_to_str (lp->ptid));
2128 /* Bugs 10970, 12702.
2129 Thread group leader may have exited in which case we'll lock up in
2130 waitpid if there are other threads, even if they are all zombies too.
2131 Basically, we're not supposed to use waitpid this way.
2132 __WCLONE is not applicable for the leader so we can't use that.
2133 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2134 process; it gets ESRCH both for the zombie and for running processes.
2136 As a workaround, check if we're waiting for the thread group leader and
2137 if it's a zombie, and avoid calling waitpid if it is.
2139 This is racy, what if the tgl becomes a zombie right after we check?
2140 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2141 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2143 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2144 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2147 if (debug_linux_nat)
2148 fprintf_unfiltered (gdb_stdlog,
2149 "WL: Thread group leader %s vanished.\n",
2150 target_pid_to_str (lp->ptid));
2154 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2155 get invoked despite our caller had them intentionally blocked by
2156 block_child_signals. This is sensitive only to the loop of
2157 linux_nat_wait_1 and there if we get called my_waitpid gets called
2158 again before it gets to sigsuspend so we can safely let the handlers
2159 get executed here. */
2161 if (debug_linux_nat)
2162 fprintf_unfiltered (gdb_stdlog, "WL: about to sigsuspend\n");
2163 sigsuspend (&suspend_mask);
2166 restore_child_signals_mask (&prev_mask);
2170 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2172 if (debug_linux_nat)
2174 fprintf_unfiltered (gdb_stdlog,
2175 "WL: waitpid %s received %s\n",
2176 target_pid_to_str (lp->ptid),
2177 status_to_str (status));
2180 /* Check if the thread has exited. */
2181 if (WIFEXITED (status) || WIFSIGNALED (status))
2184 if (debug_linux_nat)
2185 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2186 target_pid_to_str (lp->ptid));
2196 gdb_assert (WIFSTOPPED (status));
2199 if (lp->must_set_ptrace_flags)
2201 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2203 linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
2204 lp->must_set_ptrace_flags = 0;
2207 /* Handle GNU/Linux's syscall SIGTRAPs. */
2208 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2210 /* No longer need the sysgood bit. The ptrace event ends up
2211 recorded in lp->waitstatus if we care for it. We can carry
2212 on handling the event like a regular SIGTRAP from here
2214 status = W_STOPCODE (SIGTRAP);
2215 if (linux_handle_syscall_trap (lp, 1))
2216 return wait_lwp (lp);
2219 /* Handle GNU/Linux's extended waitstatus for trace events. */
2220 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
2221 && linux_is_extended_waitstatus (status))
2223 if (debug_linux_nat)
2224 fprintf_unfiltered (gdb_stdlog,
2225 "WL: Handling extended status 0x%06x\n",
2227 linux_handle_extended_wait (lp, status, 1);
2234 /* Send a SIGSTOP to LP. */
2237 stop_callback (struct lwp_info *lp, void *data)
2239 if (!lp->stopped && !lp->signalled)
2243 if (debug_linux_nat)
2245 fprintf_unfiltered (gdb_stdlog,
2246 "SC: kill %s **<SIGSTOP>**\n",
2247 target_pid_to_str (lp->ptid));
2250 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2251 if (debug_linux_nat)
2253 fprintf_unfiltered (gdb_stdlog,
2254 "SC: lwp kill %d %s\n",
2256 errno ? safe_strerror (errno) : "ERRNO-OK");
2260 gdb_assert (lp->status == 0);
2266 /* Request a stop on LWP. */
2269 linux_stop_lwp (struct lwp_info *lwp)
2271 stop_callback (lwp, NULL);
2274 /* See linux-nat.h */
2277 linux_stop_and_wait_all_lwps (void)
2279 /* Stop all LWP's ... */
2280 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
2282 /* ... and wait until all of them have reported back that
2283 they're no longer running. */
2284 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
2287 /* See linux-nat.h */
2290 linux_unstop_all_lwps (void)
2292 iterate_over_lwps (minus_one_ptid,
2293 resume_stopped_resumed_lwps, &minus_one_ptid);
2296 /* Return non-zero if LWP PID has a pending SIGINT. */
2299 linux_nat_has_pending_sigint (int pid)
2301 sigset_t pending, blocked, ignored;
2303 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2305 if (sigismember (&pending, SIGINT)
2306 && !sigismember (&ignored, SIGINT))
2312 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2315 set_ignore_sigint (struct lwp_info *lp, void *data)
2317 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2318 flag to consume the next one. */
2319 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2320 && WSTOPSIG (lp->status) == SIGINT)
2323 lp->ignore_sigint = 1;
2328 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2329 This function is called after we know the LWP has stopped; if the LWP
2330 stopped before the expected SIGINT was delivered, then it will never have
2331 arrived. Also, if the signal was delivered to a shared queue and consumed
2332 by a different thread, it will never be delivered to this LWP. */
2335 maybe_clear_ignore_sigint (struct lwp_info *lp)
2337 if (!lp->ignore_sigint)
2340 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2342 if (debug_linux_nat)
2343 fprintf_unfiltered (gdb_stdlog,
2344 "MCIS: Clearing bogus flag for %s\n",
2345 target_pid_to_str (lp->ptid));
2346 lp->ignore_sigint = 0;
2350 /* Fetch the possible triggered data watchpoint info and store it in
2353 On some archs, like x86, that use debug registers to set
2354 watchpoints, it's possible that the way to know which watched
2355 address trapped, is to check the register that is used to select
2356 which address to watch. Problem is, between setting the watchpoint
2357 and reading back which data address trapped, the user may change
2358 the set of watchpoints, and, as a consequence, GDB changes the
2359 debug registers in the inferior. To avoid reading back a stale
2360 stopped-data-address when that happens, we cache in LP the fact
2361 that a watchpoint trapped, and the corresponding data address, as
2362 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2363 registers meanwhile, we have the cached data we can rely on. */
2366 check_stopped_by_watchpoint (struct lwp_info *lp)
2368 struct cleanup *old_chain;
2370 if (linux_ops->to_stopped_by_watchpoint == NULL)
2373 old_chain = save_inferior_ptid ();
2374 inferior_ptid = lp->ptid;
2376 if (linux_ops->to_stopped_by_watchpoint (linux_ops))
2378 lp->stop_reason = TARGET_STOPPED_BY_WATCHPOINT;
2380 if (linux_ops->to_stopped_data_address != NULL)
2381 lp->stopped_data_address_p =
2382 linux_ops->to_stopped_data_address (¤t_target,
2383 &lp->stopped_data_address);
2385 lp->stopped_data_address_p = 0;
2388 do_cleanups (old_chain);
2390 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2393 /* Called when the LWP stopped for a trap that could be explained by a
2394 watchpoint or a breakpoint. */
2397 save_sigtrap (struct lwp_info *lp)
2399 gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
2400 gdb_assert (lp->status != 0);
2402 /* Check first if this was a SW/HW breakpoint before checking
2403 watchpoints, because at least s390 can't tell the data address of
2404 hardware watchpoint hits, and the kernel returns
2405 stopped-by-watchpoint as long as there's a watchpoint set. */
2406 if (linux_nat_status_is_event (lp->status))
2407 check_stopped_by_breakpoint (lp);
2409 /* Note that TRAP_HWBKPT can indicate either a hardware breakpoint
2410 or hardware watchpoint. Check which is which if we got
2411 TARGET_STOPPED_BY_HW_BREAKPOINT. */
2412 if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON
2413 || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2414 check_stopped_by_watchpoint (lp);
2417 /* Returns true if the LWP had stopped for a watchpoint. */
2420 linux_nat_stopped_by_watchpoint (struct target_ops *ops)
2422 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2424 gdb_assert (lp != NULL);
2426 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2430 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2432 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2434 gdb_assert (lp != NULL);
2436 *addr_p = lp->stopped_data_address;
2438 return lp->stopped_data_address_p;
2441 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2444 sigtrap_is_event (int status)
2446 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2449 /* Set alternative SIGTRAP-like events recognizer. If
2450 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2454 linux_nat_set_status_is_event (struct target_ops *t,
2455 int (*status_is_event) (int status))
2457 linux_nat_status_is_event = status_is_event;
2460 /* Wait until LP is stopped. */
2463 stop_wait_callback (struct lwp_info *lp, void *data)
2465 struct inferior *inf = find_inferior_ptid (lp->ptid);
2467 /* If this is a vfork parent, bail out, it is not going to report
2468 any SIGSTOP until the vfork is done with. */
2469 if (inf->vfork_child != NULL)
2476 status = wait_lwp (lp);
2480 if (lp->ignore_sigint && WIFSTOPPED (status)
2481 && WSTOPSIG (status) == SIGINT)
2483 lp->ignore_sigint = 0;
2486 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2488 if (debug_linux_nat)
2489 fprintf_unfiltered (gdb_stdlog,
2490 "PTRACE_CONT %s, 0, 0 (%s) "
2491 "(discarding SIGINT)\n",
2492 target_pid_to_str (lp->ptid),
2493 errno ? safe_strerror (errno) : "OK");
2495 return stop_wait_callback (lp, NULL);
2498 maybe_clear_ignore_sigint (lp);
2500 if (WSTOPSIG (status) != SIGSTOP)
2502 /* The thread was stopped with a signal other than SIGSTOP. */
2504 if (debug_linux_nat)
2505 fprintf_unfiltered (gdb_stdlog,
2506 "SWC: Pending event %s in %s\n",
2507 status_to_str ((int) status),
2508 target_pid_to_str (lp->ptid));
2510 /* Save the sigtrap event. */
2511 lp->status = status;
2512 gdb_assert (lp->signalled);
2517 /* We caught the SIGSTOP that we intended to catch, so
2518 there's no SIGSTOP pending. */
2520 if (debug_linux_nat)
2521 fprintf_unfiltered (gdb_stdlog,
2522 "SWC: Delayed SIGSTOP caught for %s.\n",
2523 target_pid_to_str (lp->ptid));
2525 /* Reset SIGNALLED only after the stop_wait_callback call
2526 above as it does gdb_assert on SIGNALLED. */
2534 /* Return non-zero if LP has a wait status pending. Discard the
2535 pending event and resume the LWP if the event that originally
2536 caused the stop became uninteresting. */
2539 status_callback (struct lwp_info *lp, void *data)
2541 /* Only report a pending wait status if we pretend that this has
2542 indeed been resumed. */
2546 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
2547 || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2549 struct regcache *regcache = get_thread_regcache (lp->ptid);
2550 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2554 gdb_assert (lp->status != 0);
2556 pc = regcache_read_pc (regcache);
2558 if (pc != lp->stop_pc)
2560 if (debug_linux_nat)
2561 fprintf_unfiltered (gdb_stdlog,
2562 "SC: PC of %s changed. was=%s, now=%s\n",
2563 target_pid_to_str (lp->ptid),
2564 paddress (target_gdbarch (), lp->stop_pc),
2565 paddress (target_gdbarch (), pc));
2569 #if !USE_SIGTRAP_SIGINFO
2570 else if (!breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2572 if (debug_linux_nat)
2573 fprintf_unfiltered (gdb_stdlog,
2574 "SC: previous breakpoint of %s, at %s gone\n",
2575 target_pid_to_str (lp->ptid),
2576 paddress (target_gdbarch (), lp->stop_pc));
2584 if (debug_linux_nat)
2585 fprintf_unfiltered (gdb_stdlog,
2586 "SC: pending event of %s cancelled.\n",
2587 target_pid_to_str (lp->ptid));
2590 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
2596 return lwp_status_pending_p (lp);
2599 /* Return non-zero if LP isn't stopped. */
2602 running_callback (struct lwp_info *lp, void *data)
2604 return (!lp->stopped
2605 || (lwp_status_pending_p (lp) && lp->resumed));
2608 /* Count the LWP's that have had events. */
2611 count_events_callback (struct lwp_info *lp, void *data)
2615 gdb_assert (count != NULL);
2617 /* Select only resumed LWPs that have an event pending. */
2618 if (lp->resumed && lwp_status_pending_p (lp))
2624 /* Select the LWP (if any) that is currently being single-stepped. */
2627 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2629 if (lp->last_resume_kind == resume_step
2636 /* Returns true if LP has a status pending. */
2639 lwp_status_pending_p (struct lwp_info *lp)
2641 /* We check for lp->waitstatus in addition to lp->status, because we
2642 can have pending process exits recorded in lp->status and
2643 W_EXITCODE(0,0) happens to be 0. */
2644 return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE;
2647 /* Select the Nth LWP that has had a SIGTRAP event. */
2650 select_event_lwp_callback (struct lwp_info *lp, void *data)
2652 int *selector = data;
2654 gdb_assert (selector != NULL);
2656 /* Select only resumed LWPs that have an event pending. */
2657 if (lp->resumed && lwp_status_pending_p (lp))
2658 if ((*selector)-- == 0)
2664 /* Called when the LWP got a signal/trap that could be explained by a
2665 software or hardware breakpoint. */
2668 check_stopped_by_breakpoint (struct lwp_info *lp)
2670 /* Arrange for a breakpoint to be hit again later. We don't keep
2671 the SIGTRAP status and don't forward the SIGTRAP signal to the
2672 LWP. We will handle the current event, eventually we will resume
2673 this LWP, and this breakpoint will trap again.
2675 If we do not do this, then we run the risk that the user will
2676 delete or disable the breakpoint, but the LWP will have already
2679 struct regcache *regcache = get_thread_regcache (lp->ptid);
2680 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2683 #if USE_SIGTRAP_SIGINFO
2687 pc = regcache_read_pc (regcache);
2688 sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch);
2690 #if USE_SIGTRAP_SIGINFO
2691 if (linux_nat_get_siginfo (lp->ptid, &siginfo))
2693 if (siginfo.si_signo == SIGTRAP)
2695 if (siginfo.si_code == GDB_ARCH_TRAP_BRKPT)
2697 if (debug_linux_nat)
2698 fprintf_unfiltered (gdb_stdlog,
2699 "CSBB: Push back software "
2700 "breakpoint for %s\n",
2701 target_pid_to_str (lp->ptid));
2703 /* Back up the PC if necessary. */
2705 regcache_write_pc (regcache, sw_bp_pc);
2707 lp->stop_pc = sw_bp_pc;
2708 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2711 else if (siginfo.si_code == TRAP_HWBKPT)
2713 if (debug_linux_nat)
2714 fprintf_unfiltered (gdb_stdlog,
2715 "CSBB: Push back hardware "
2716 "breakpoint/watchpoint for %s\n",
2717 target_pid_to_str (lp->ptid));
2720 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2726 if ((!lp->step || lp->stop_pc == sw_bp_pc)
2727 && software_breakpoint_inserted_here_p (get_regcache_aspace (regcache),
2730 /* The LWP was either continued, or stepped a software
2731 breakpoint instruction. */
2732 if (debug_linux_nat)
2733 fprintf_unfiltered (gdb_stdlog,
2734 "CB: Push back software breakpoint for %s\n",
2735 target_pid_to_str (lp->ptid));
2737 /* Back up the PC if necessary. */
2739 regcache_write_pc (regcache, sw_bp_pc);
2741 lp->stop_pc = sw_bp_pc;
2742 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2746 if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2748 if (debug_linux_nat)
2749 fprintf_unfiltered (gdb_stdlog,
2750 "CB: Push back hardware breakpoint for %s\n",
2751 target_pid_to_str (lp->ptid));
2754 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2763 /* Returns true if the LWP had stopped for a software breakpoint. */
2766 linux_nat_stopped_by_sw_breakpoint (struct target_ops *ops)
2768 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2770 gdb_assert (lp != NULL);
2772 return lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT;
2775 /* Implement the supports_stopped_by_sw_breakpoint method. */
2778 linux_nat_supports_stopped_by_sw_breakpoint (struct target_ops *ops)
2780 return USE_SIGTRAP_SIGINFO;
2783 /* Returns true if the LWP had stopped for a hardware
2784 breakpoint/watchpoint. */
2787 linux_nat_stopped_by_hw_breakpoint (struct target_ops *ops)
2789 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2791 gdb_assert (lp != NULL);
2793 return lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT;
2796 /* Implement the supports_stopped_by_hw_breakpoint method. */
2799 linux_nat_supports_stopped_by_hw_breakpoint (struct target_ops *ops)
2801 return USE_SIGTRAP_SIGINFO;
2804 /* Select one LWP out of those that have events pending. */
2807 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2810 int random_selector;
2811 struct lwp_info *event_lp = NULL;
2813 /* Record the wait status for the original LWP. */
2814 (*orig_lp)->status = *status;
2816 /* In all-stop, give preference to the LWP that is being
2817 single-stepped. There will be at most one, and it will be the
2818 LWP that the core is most interested in. If we didn't do this,
2819 then we'd have to handle pending step SIGTRAPs somehow in case
2820 the core later continues the previously-stepped thread, as
2821 otherwise we'd report the pending SIGTRAP then, and the core, not
2822 having stepped the thread, wouldn't understand what the trap was
2823 for, and therefore would report it to the user as a random
2827 event_lp = iterate_over_lwps (filter,
2828 select_singlestep_lwp_callback, NULL);
2829 if (event_lp != NULL)
2831 if (debug_linux_nat)
2832 fprintf_unfiltered (gdb_stdlog,
2833 "SEL: Select single-step %s\n",
2834 target_pid_to_str (event_lp->ptid));
2838 if (event_lp == NULL)
2840 /* Pick one at random, out of those which have had events. */
2842 /* First see how many events we have. */
2843 iterate_over_lwps (filter, count_events_callback, &num_events);
2845 /* Now randomly pick a LWP out of those that have had
2847 random_selector = (int)
2848 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2850 if (debug_linux_nat && num_events > 1)
2851 fprintf_unfiltered (gdb_stdlog,
2852 "SEL: Found %d events, selecting #%d\n",
2853 num_events, random_selector);
2855 event_lp = iterate_over_lwps (filter,
2856 select_event_lwp_callback,
2860 if (event_lp != NULL)
2862 /* Switch the event LWP. */
2863 *orig_lp = event_lp;
2864 *status = event_lp->status;
2867 /* Flush the wait status for the event LWP. */
2868 (*orig_lp)->status = 0;
2871 /* Return non-zero if LP has been resumed. */
2874 resumed_callback (struct lwp_info *lp, void *data)
2879 /* Stop an active thread, verify it still exists, then resume it. If
2880 the thread ends up with a pending status, then it is not resumed,
2881 and *DATA (really a pointer to int), is set. */
2884 stop_and_resume_callback (struct lwp_info *lp, void *data)
2888 ptid_t ptid = lp->ptid;
2890 stop_callback (lp, NULL);
2891 stop_wait_callback (lp, NULL);
2893 /* Resume if the lwp still exists, and the core wanted it
2895 lp = find_lwp_pid (ptid);
2898 if (lp->last_resume_kind == resume_stop
2899 && !lwp_status_pending_p (lp))
2901 /* The core wanted the LWP to stop. Even if it stopped
2902 cleanly (with SIGSTOP), leave the event pending. */
2903 if (debug_linux_nat)
2904 fprintf_unfiltered (gdb_stdlog,
2905 "SARC: core wanted LWP %ld stopped "
2906 "(leaving SIGSTOP pending)\n",
2907 ptid_get_lwp (lp->ptid));
2908 lp->status = W_STOPCODE (SIGSTOP);
2911 if (!lwp_status_pending_p (lp))
2913 if (debug_linux_nat)
2914 fprintf_unfiltered (gdb_stdlog,
2915 "SARC: re-resuming LWP %ld\n",
2916 ptid_get_lwp (lp->ptid));
2917 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2921 if (debug_linux_nat)
2922 fprintf_unfiltered (gdb_stdlog,
2923 "SARC: not re-resuming LWP %ld "
2925 ptid_get_lwp (lp->ptid));
2932 /* Check if we should go on and pass this event to common code.
2933 Return the affected lwp if we are, or NULL otherwise. */
2935 static struct lwp_info *
2936 linux_nat_filter_event (int lwpid, int status)
2938 struct lwp_info *lp;
2939 int event = linux_ptrace_get_extended_event (status);
2941 lp = find_lwp_pid (pid_to_ptid (lwpid));
2943 /* Check for stop events reported by a process we didn't already
2944 know about - anything not already in our LWP list.
2946 If we're expecting to receive stopped processes after
2947 fork, vfork, and clone events, then we'll just add the
2948 new one to our list and go back to waiting for the event
2949 to be reported - the stopped process might be returned
2950 from waitpid before or after the event is.
2952 But note the case of a non-leader thread exec'ing after the
2953 leader having exited, and gone from our lists. The non-leader
2954 thread changes its tid to the tgid. */
2956 if (WIFSTOPPED (status) && lp == NULL
2957 && (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
2959 /* A multi-thread exec after we had seen the leader exiting. */
2960 if (debug_linux_nat)
2961 fprintf_unfiltered (gdb_stdlog,
2962 "LLW: Re-adding thread group leader LWP %d.\n",
2965 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2968 add_thread (lp->ptid);
2971 if (WIFSTOPPED (status) && !lp)
2973 if (debug_linux_nat)
2974 fprintf_unfiltered (gdb_stdlog,
2975 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2976 (long) lwpid, status_to_str (status));
2977 add_to_pid_list (&stopped_pids, lwpid, status);
2981 /* Make sure we don't report an event for the exit of an LWP not in
2982 our list, i.e. not part of the current process. This can happen
2983 if we detach from a program we originally forked and then it
2985 if (!WIFSTOPPED (status) && !lp)
2988 /* This LWP is stopped now. (And if dead, this prevents it from
2989 ever being continued.) */
2992 if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
2994 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2996 linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
2997 lp->must_set_ptrace_flags = 0;
3000 /* Handle GNU/Linux's syscall SIGTRAPs. */
3001 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
3003 /* No longer need the sysgood bit. The ptrace event ends up
3004 recorded in lp->waitstatus if we care for it. We can carry
3005 on handling the event like a regular SIGTRAP from here
3007 status = W_STOPCODE (SIGTRAP);
3008 if (linux_handle_syscall_trap (lp, 0))
3012 /* Handle GNU/Linux's extended waitstatus for trace events. */
3013 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
3014 && linux_is_extended_waitstatus (status))
3016 if (debug_linux_nat)
3017 fprintf_unfiltered (gdb_stdlog,
3018 "LLW: Handling extended status 0x%06x\n",
3020 if (linux_handle_extended_wait (lp, status, 0))
3024 /* Check if the thread has exited. */
3025 if (WIFEXITED (status) || WIFSIGNALED (status))
3027 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3029 /* If this is the main thread, we must stop all threads and
3030 verify if they are still alive. This is because in the
3031 nptl thread model on Linux 2.4, there is no signal issued
3032 for exiting LWPs other than the main thread. We only get
3033 the main thread exit signal once all child threads have
3034 already exited. If we stop all the threads and use the
3035 stop_wait_callback to check if they have exited we can
3036 determine whether this signal should be ignored or
3037 whether it means the end of the debugged application,
3038 regardless of which threading model is being used. */
3039 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
3041 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3042 stop_and_resume_callback, NULL);
3045 if (debug_linux_nat)
3046 fprintf_unfiltered (gdb_stdlog,
3047 "LLW: %s exited.\n",
3048 target_pid_to_str (lp->ptid));
3050 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3052 /* If there is at least one more LWP, then the exit signal
3053 was not the end of the debugged application and should be
3060 gdb_assert (lp->resumed);
3062 if (debug_linux_nat)
3063 fprintf_unfiltered (gdb_stdlog,
3064 "Process %ld exited\n",
3065 ptid_get_lwp (lp->ptid));
3067 /* This was the last lwp in the process. Since events are
3068 serialized to GDB core, we may not be able report this one
3069 right now, but GDB core and the other target layers will want
3070 to be notified about the exit code/signal, leave the status
3071 pending for the next time we're able to report it. */
3073 /* Dead LWP's aren't expected to reported a pending sigstop. */
3076 /* Store the pending event in the waitstatus, because
3077 W_EXITCODE(0,0) == 0. */
3078 store_waitstatus (&lp->waitstatus, status);
3082 /* Check if the current LWP has previously exited. In the nptl
3083 thread model, LWPs other than the main thread do not issue
3084 signals when they exit so we must check whenever the thread has
3085 stopped. A similar check is made in stop_wait_callback(). */
3086 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3088 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3090 if (debug_linux_nat)
3091 fprintf_unfiltered (gdb_stdlog,
3092 "LLW: %s exited.\n",
3093 target_pid_to_str (lp->ptid));
3097 /* Make sure there is at least one thread running. */
3098 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3100 /* Discard the event. */
3104 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3105 an attempt to stop an LWP. */
3107 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3109 if (debug_linux_nat)
3110 fprintf_unfiltered (gdb_stdlog,
3111 "LLW: Delayed SIGSTOP caught for %s.\n",
3112 target_pid_to_str (lp->ptid));
3116 if (lp->last_resume_kind != resume_stop)
3118 /* This is a delayed SIGSTOP. */
3120 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3121 if (debug_linux_nat)
3122 fprintf_unfiltered (gdb_stdlog,
3123 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3125 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3126 target_pid_to_str (lp->ptid));
3128 gdb_assert (lp->resumed);
3130 /* Discard the event. */
3135 /* Make sure we don't report a SIGINT that we have already displayed
3136 for another thread. */
3137 if (lp->ignore_sigint
3138 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3140 if (debug_linux_nat)
3141 fprintf_unfiltered (gdb_stdlog,
3142 "LLW: Delayed SIGINT caught for %s.\n",
3143 target_pid_to_str (lp->ptid));
3145 /* This is a delayed SIGINT. */
3146 lp->ignore_sigint = 0;
3148 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3149 if (debug_linux_nat)
3150 fprintf_unfiltered (gdb_stdlog,
3151 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3153 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3154 target_pid_to_str (lp->ptid));
3155 gdb_assert (lp->resumed);
3157 /* Discard the event. */
3161 /* Don't report signals that GDB isn't interested in, such as
3162 signals that are neither printed nor stopped upon. Stopping all
3163 threads can be a bit time-consuming so if we want decent
3164 performance with heavily multi-threaded programs, especially when
3165 they're using a high frequency timer, we'd better avoid it if we
3167 if (WIFSTOPPED (status))
3169 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3173 /* Only do the below in all-stop, as we currently use SIGSTOP
3174 to implement target_stop (see linux_nat_stop) in
3176 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3178 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3179 forwarded to the entire process group, that is, all LWPs
3180 will receive it - unless they're using CLONE_THREAD to
3181 share signals. Since we only want to report it once, we
3182 mark it as ignored for all LWPs except this one. */
3183 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3184 set_ignore_sigint, NULL);
3185 lp->ignore_sigint = 0;
3188 maybe_clear_ignore_sigint (lp);
3191 /* When using hardware single-step, we need to report every signal.
3192 Otherwise, signals in pass_mask may be short-circuited
3193 except signals that might be caused by a breakpoint. */
3195 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status))
3196 && !linux_wstatus_maybe_breakpoint (status))
3198 linux_resume_one_lwp (lp, lp->step, signo);
3199 if (debug_linux_nat)
3200 fprintf_unfiltered (gdb_stdlog,
3201 "LLW: %s %s, %s (preempt 'handle')\n",
3203 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3204 target_pid_to_str (lp->ptid),
3205 (signo != GDB_SIGNAL_0
3206 ? strsignal (gdb_signal_to_host (signo))
3212 /* An interesting event. */
3214 lp->status = status;
3219 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3220 their exits until all other threads in the group have exited. */
3223 check_zombie_leaders (void)
3225 struct inferior *inf;
3229 struct lwp_info *leader_lp;
3234 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3235 if (leader_lp != NULL
3236 /* Check if there are other threads in the group, as we may
3237 have raced with the inferior simply exiting. */
3238 && num_lwps (inf->pid) > 1
3239 && linux_proc_pid_is_zombie (inf->pid))
3241 if (debug_linux_nat)
3242 fprintf_unfiltered (gdb_stdlog,
3243 "CZL: Thread group leader %d zombie "
3244 "(it exited, or another thread execd).\n",
3247 /* A leader zombie can mean one of two things:
3249 - It exited, and there's an exit status pending
3250 available, or only the leader exited (not the whole
3251 program). In the latter case, we can't waitpid the
3252 leader's exit status until all other threads are gone.
3254 - There are 3 or more threads in the group, and a thread
3255 other than the leader exec'd. On an exec, the Linux
3256 kernel destroys all other threads (except the execing
3257 one) in the thread group, and resets the execing thread's
3258 tid to the tgid. No exit notification is sent for the
3259 execing thread -- from the ptracer's perspective, it
3260 appears as though the execing thread just vanishes.
3261 Until we reap all other threads except the leader and the
3262 execing thread, the leader will be zombie, and the
3263 execing thread will be in `D (disc sleep)'. As soon as
3264 all other threads are reaped, the execing thread changes
3265 it's tid to the tgid, and the previous (zombie) leader
3266 vanishes, giving place to the "new" leader. We could try
3267 distinguishing the exit and exec cases, by waiting once
3268 more, and seeing if something comes out, but it doesn't
3269 sound useful. The previous leader _does_ go away, and
3270 we'll re-add the new one once we see the exec event
3271 (which is just the same as what would happen if the
3272 previous leader did exit voluntarily before some other
3275 if (debug_linux_nat)
3276 fprintf_unfiltered (gdb_stdlog,
3277 "CZL: Thread group leader %d vanished.\n",
3279 exit_lwp (leader_lp);
3285 linux_nat_wait_1 (struct target_ops *ops,
3286 ptid_t ptid, struct target_waitstatus *ourstatus,
3290 enum resume_kind last_resume_kind;
3291 struct lwp_info *lp;
3294 if (debug_linux_nat)
3295 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3297 /* The first time we get here after starting a new inferior, we may
3298 not have added it to the LWP list yet - this is the earliest
3299 moment at which we know its PID. */
3300 if (ptid_is_pid (inferior_ptid))
3302 /* Upgrade the main thread's ptid. */
3303 thread_change_ptid (inferior_ptid,
3304 ptid_build (ptid_get_pid (inferior_ptid),
3305 ptid_get_pid (inferior_ptid), 0));
3307 lp = add_initial_lwp (inferior_ptid);
3311 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3312 block_child_signals (&prev_mask);
3314 /* First check if there is a LWP with a wait status pending. */
3315 lp = iterate_over_lwps (ptid, status_callback, NULL);
3318 if (debug_linux_nat)
3319 fprintf_unfiltered (gdb_stdlog,
3320 "LLW: Using pending wait status %s for %s.\n",
3321 status_to_str (lp->status),
3322 target_pid_to_str (lp->ptid));
3325 if (!target_is_async_p ())
3327 /* Causes SIGINT to be passed on to the attached process. */
3331 /* But if we don't find a pending event, we'll have to wait. Always
3332 pull all events out of the kernel. We'll randomly select an
3333 event LWP out of all that have events, to prevent starvation. */
3339 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3342 - If the thread group leader exits while other threads in the
3343 thread group still exist, waitpid(TGID, ...) hangs. That
3344 waitpid won't return an exit status until the other threads
3345 in the group are reapped.
3347 - When a non-leader thread execs, that thread just vanishes
3348 without reporting an exit (so we'd hang if we waited for it
3349 explicitly in that case). The exec event is reported to
3353 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3354 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3355 lwpid = my_waitpid (-1, &status, WNOHANG);
3357 if (debug_linux_nat)
3358 fprintf_unfiltered (gdb_stdlog,
3359 "LNW: waitpid(-1, ...) returned %d, %s\n",
3360 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3364 if (debug_linux_nat)
3366 fprintf_unfiltered (gdb_stdlog,
3367 "LLW: waitpid %ld received %s\n",
3368 (long) lwpid, status_to_str (status));
3371 linux_nat_filter_event (lwpid, status);
3372 /* Retry until nothing comes out of waitpid. A single
3373 SIGCHLD can indicate more than one child stopped. */
3377 /* Now that we've pulled all events out of the kernel, resume
3378 LWPs that don't have an interesting event to report. */
3379 iterate_over_lwps (minus_one_ptid,
3380 resume_stopped_resumed_lwps, &minus_one_ptid);
3382 /* ... and find an LWP with a status to report to the core, if
3384 lp = iterate_over_lwps (ptid, status_callback, NULL);
3388 /* Check for zombie thread group leaders. Those can't be reaped
3389 until all other threads in the thread group are. */
3390 check_zombie_leaders ();
3392 /* If there are no resumed children left, bail. We'd be stuck
3393 forever in the sigsuspend call below otherwise. */
3394 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3396 if (debug_linux_nat)
3397 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3399 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3401 if (!target_is_async_p ())
3402 clear_sigint_trap ();
3404 restore_child_signals_mask (&prev_mask);
3405 return minus_one_ptid;
3408 /* No interesting event to report to the core. */
3410 if (target_options & TARGET_WNOHANG)
3412 if (debug_linux_nat)
3413 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3415 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3416 restore_child_signals_mask (&prev_mask);
3417 return minus_one_ptid;
3420 /* We shouldn't end up here unless we want to try again. */
3421 gdb_assert (lp == NULL);
3423 /* Block until we get an event reported with SIGCHLD. */
3424 if (debug_linux_nat)
3425 fprintf_unfiltered (gdb_stdlog, "LNW: about to sigsuspend\n");
3426 sigsuspend (&suspend_mask);
3429 if (!target_is_async_p ())
3430 clear_sigint_trap ();
3434 status = lp->status;
3439 /* Now stop all other LWP's ... */
3440 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3442 /* ... and wait until all of them have reported back that
3443 they're no longer running. */
3444 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3447 /* If we're not waiting for a specific LWP, choose an event LWP from
3448 among those that have had events. Giving equal priority to all
3449 LWPs that have had events helps prevent starvation. */
3450 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3451 select_event_lwp (ptid, &lp, &status);
3453 gdb_assert (lp != NULL);
3455 /* Now that we've selected our final event LWP, un-adjust its PC if
3456 it was a software breakpoint, and we can't reliably support the
3457 "stopped by software breakpoint" stop reason. */
3458 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
3459 && !USE_SIGTRAP_SIGINFO)
3461 struct regcache *regcache = get_thread_regcache (lp->ptid);
3462 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3463 int decr_pc = gdbarch_decr_pc_after_break (gdbarch);
3469 pc = regcache_read_pc (regcache);
3470 regcache_write_pc (regcache, pc + decr_pc);
3474 /* We'll need this to determine whether to report a SIGSTOP as
3475 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3477 last_resume_kind = lp->last_resume_kind;
3481 /* In all-stop, from the core's perspective, all LWPs are now
3482 stopped until a new resume action is sent over. */
3483 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3487 resume_clear_callback (lp, NULL);
3490 if (linux_nat_status_is_event (status))
3492 if (debug_linux_nat)
3493 fprintf_unfiltered (gdb_stdlog,
3494 "LLW: trap ptid is %s.\n",
3495 target_pid_to_str (lp->ptid));
3498 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3500 *ourstatus = lp->waitstatus;
3501 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3504 store_waitstatus (ourstatus, status);
3506 if (debug_linux_nat)
3507 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3509 restore_child_signals_mask (&prev_mask);
3511 if (last_resume_kind == resume_stop
3512 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3513 && WSTOPSIG (status) == SIGSTOP)
3515 /* A thread that has been requested to stop by GDB with
3516 target_stop, and it stopped cleanly, so report as SIG0. The
3517 use of SIGSTOP is an implementation detail. */
3518 ourstatus->value.sig = GDB_SIGNAL_0;
3521 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3522 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3525 lp->core = linux_common_core_of_thread (lp->ptid);
3530 /* Resume LWPs that are currently stopped without any pending status
3531 to report, but are resumed from the core's perspective. */
3534 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3536 ptid_t *wait_ptid_p = data;
3540 && !lwp_status_pending_p (lp))
3542 struct regcache *regcache = get_thread_regcache (lp->ptid);
3543 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3544 CORE_ADDR pc = regcache_read_pc (regcache);
3546 /* Don't bother if there's a breakpoint at PC that we'd hit
3547 immediately, and we're not waiting for this LWP. */
3548 if (!ptid_match (lp->ptid, *wait_ptid_p))
3550 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3554 if (debug_linux_nat)
3555 fprintf_unfiltered (gdb_stdlog,
3556 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3557 target_pid_to_str (lp->ptid),
3558 paddress (gdbarch, pc),
3561 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3568 linux_nat_wait (struct target_ops *ops,
3569 ptid_t ptid, struct target_waitstatus *ourstatus,
3574 if (debug_linux_nat)
3576 char *options_string;
3578 options_string = target_options_to_string (target_options);
3579 fprintf_unfiltered (gdb_stdlog,
3580 "linux_nat_wait: [%s], [%s]\n",
3581 target_pid_to_str (ptid),
3583 xfree (options_string);
3586 /* Flush the async file first. */
3587 if (target_is_async_p ())
3588 async_file_flush ();
3590 /* Resume LWPs that are currently stopped without any pending status
3591 to report, but are resumed from the core's perspective. LWPs get
3592 in this state if we find them stopping at a time we're not
3593 interested in reporting the event (target_wait on a
3594 specific_process, for example, see linux_nat_wait_1), and
3595 meanwhile the event became uninteresting. Don't bother resuming
3596 LWPs we're not going to wait for if they'd stop immediately. */
3598 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3600 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3602 /* If we requested any event, and something came out, assume there
3603 may be more. If we requested a specific lwp or process, also
3604 assume there may be more. */
3605 if (target_is_async_p ()
3606 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3607 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3608 || !ptid_equal (ptid, minus_one_ptid)))
3615 kill_callback (struct lwp_info *lp, void *data)
3617 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3620 kill_lwp (ptid_get_lwp (lp->ptid), SIGKILL);
3621 if (debug_linux_nat)
3623 int save_errno = errno;
3625 fprintf_unfiltered (gdb_stdlog,
3626 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3627 target_pid_to_str (lp->ptid),
3628 save_errno ? safe_strerror (save_errno) : "OK");
3631 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3634 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3635 if (debug_linux_nat)
3637 int save_errno = errno;
3639 fprintf_unfiltered (gdb_stdlog,
3640 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3641 target_pid_to_str (lp->ptid),
3642 save_errno ? safe_strerror (save_errno) : "OK");
3649 kill_wait_callback (struct lwp_info *lp, void *data)
3653 /* We must make sure that there are no pending events (delayed
3654 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3655 program doesn't interfere with any following debugging session. */
3657 /* For cloned processes we must check both with __WCLONE and
3658 without, since the exit status of a cloned process isn't reported
3664 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3665 if (pid != (pid_t) -1)
3667 if (debug_linux_nat)
3668 fprintf_unfiltered (gdb_stdlog,
3669 "KWC: wait %s received unknown.\n",
3670 target_pid_to_str (lp->ptid));
3671 /* The Linux kernel sometimes fails to kill a thread
3672 completely after PTRACE_KILL; that goes from the stop
3673 point in do_fork out to the one in
3674 get_signal_to_deliever and waits again. So kill it
3676 kill_callback (lp, NULL);
3679 while (pid == ptid_get_lwp (lp->ptid));
3681 gdb_assert (pid == -1 && errno == ECHILD);
3686 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3687 if (pid != (pid_t) -1)
3689 if (debug_linux_nat)
3690 fprintf_unfiltered (gdb_stdlog,
3691 "KWC: wait %s received unk.\n",
3692 target_pid_to_str (lp->ptid));
3693 /* See the call to kill_callback above. */
3694 kill_callback (lp, NULL);
3697 while (pid == ptid_get_lwp (lp->ptid));
3699 gdb_assert (pid == -1 && errno == ECHILD);
3704 linux_nat_kill (struct target_ops *ops)
3706 struct target_waitstatus last;
3710 /* If we're stopped while forking and we haven't followed yet,
3711 kill the other task. We need to do this first because the
3712 parent will be sleeping if this is a vfork. */
3714 get_last_target_status (&last_ptid, &last);
3716 if (last.kind == TARGET_WAITKIND_FORKED
3717 || last.kind == TARGET_WAITKIND_VFORKED)
3719 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3722 /* Let the arch-specific native code know this process is
3724 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3727 if (forks_exist_p ())
3728 linux_fork_killall ();
3731 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3733 /* Stop all threads before killing them, since ptrace requires
3734 that the thread is stopped to sucessfully PTRACE_KILL. */
3735 iterate_over_lwps (ptid, stop_callback, NULL);
3736 /* ... and wait until all of them have reported back that
3737 they're no longer running. */
3738 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3740 /* Kill all LWP's ... */
3741 iterate_over_lwps (ptid, kill_callback, NULL);
3743 /* ... and wait until we've flushed all events. */
3744 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3747 target_mourn_inferior ();
3751 linux_nat_mourn_inferior (struct target_ops *ops)
3753 int pid = ptid_get_pid (inferior_ptid);
3755 purge_lwp_list (pid);
3757 if (! forks_exist_p ())
3758 /* Normal case, no other forks available. */
3759 linux_ops->to_mourn_inferior (ops);
3761 /* Multi-fork case. The current inferior_ptid has exited, but
3762 there are other viable forks to debug. Delete the exiting
3763 one and context-switch to the first available. */
3764 linux_fork_mourn_inferior ();
3766 /* Let the arch-specific native code know this process is gone. */
3767 linux_nat_forget_process (pid);
3770 /* Convert a native/host siginfo object, into/from the siginfo in the
3771 layout of the inferiors' architecture. */
3774 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3778 if (linux_nat_siginfo_fixup != NULL)
3779 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3781 /* If there was no callback, or the callback didn't do anything,
3782 then just do a straight memcpy. */
3786 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3788 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3792 static enum target_xfer_status
3793 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3794 const char *annex, gdb_byte *readbuf,
3795 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3796 ULONGEST *xfered_len)
3800 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3802 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3803 gdb_assert (readbuf || writebuf);
3805 pid = ptid_get_lwp (inferior_ptid);
3807 pid = ptid_get_pid (inferior_ptid);
3809 if (offset > sizeof (siginfo))
3810 return TARGET_XFER_E_IO;
3813 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3815 return TARGET_XFER_E_IO;
3817 /* When GDB is built as a 64-bit application, ptrace writes into
3818 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3819 inferior with a 64-bit GDB should look the same as debugging it
3820 with a 32-bit GDB, we need to convert it. GDB core always sees
3821 the converted layout, so any read/write will have to be done
3823 siginfo_fixup (&siginfo, inf_siginfo, 0);
3825 if (offset + len > sizeof (siginfo))
3826 len = sizeof (siginfo) - offset;
3828 if (readbuf != NULL)
3829 memcpy (readbuf, inf_siginfo + offset, len);
3832 memcpy (inf_siginfo + offset, writebuf, len);
3834 /* Convert back to ptrace layout before flushing it out. */
3835 siginfo_fixup (&siginfo, inf_siginfo, 1);
3838 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3840 return TARGET_XFER_E_IO;
3844 return TARGET_XFER_OK;
3847 static enum target_xfer_status
3848 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3849 const char *annex, gdb_byte *readbuf,
3850 const gdb_byte *writebuf,
3851 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3853 struct cleanup *old_chain;
3854 enum target_xfer_status xfer;
3856 if (object == TARGET_OBJECT_SIGNAL_INFO)
3857 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3858 offset, len, xfered_len);
3860 /* The target is connected but no live inferior is selected. Pass
3861 this request down to a lower stratum (e.g., the executable
3863 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3864 return TARGET_XFER_EOF;
3866 old_chain = save_inferior_ptid ();
3868 if (ptid_lwp_p (inferior_ptid))
3869 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3871 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3872 offset, len, xfered_len);
3874 do_cleanups (old_chain);
3879 linux_thread_alive (ptid_t ptid)
3883 gdb_assert (ptid_lwp_p (ptid));
3885 /* Send signal 0 instead of anything ptrace, because ptracing a
3886 running thread errors out claiming that the thread doesn't
3888 err = kill_lwp (ptid_get_lwp (ptid), 0);
3890 if (debug_linux_nat)
3891 fprintf_unfiltered (gdb_stdlog,
3892 "LLTA: KILL(SIG0) %s (%s)\n",
3893 target_pid_to_str (ptid),
3894 err ? safe_strerror (tmp_errno) : "OK");
3903 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3905 return linux_thread_alive (ptid);
3909 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3911 static char buf[64];
3913 if (ptid_lwp_p (ptid)
3914 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
3915 || num_lwps (ptid_get_pid (ptid)) > 1))
3917 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
3921 return normal_pid_to_str (ptid);
3925 linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
3927 int pid = ptid_get_pid (thr->ptid);
3928 long lwp = ptid_get_lwp (thr->ptid);
3929 #define FORMAT "/proc/%d/task/%ld/comm"
3930 char buf[sizeof (FORMAT) + 30];
3932 char *result = NULL;
3934 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
3935 comm_file = gdb_fopen_cloexec (buf, "r");
3938 /* Not exported by the kernel, so we define it here. */
3940 static char line[COMM_LEN + 1];
3942 if (fgets (line, sizeof (line), comm_file))
3944 char *nl = strchr (line, '\n');
3961 /* Accepts an integer PID; Returns a string representing a file that
3962 can be opened to get the symbols for the child process. */
3965 linux_child_pid_to_exec_file (struct target_ops *self, int pid)
3967 static char buf[PATH_MAX];
3968 char name[PATH_MAX];
3970 xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
3971 memset (buf, 0, PATH_MAX);
3972 if (readlink (name, buf, PATH_MAX - 1) <= 0)
3978 /* Implement the to_xfer_partial interface for memory reads using the /proc
3979 filesystem. Because we can use a single read() call for /proc, this
3980 can be much more efficient than banging away at PTRACE_PEEKTEXT,
3981 but it doesn't support writes. */
3983 static enum target_xfer_status
3984 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
3985 const char *annex, gdb_byte *readbuf,
3986 const gdb_byte *writebuf,
3987 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
3993 if (object != TARGET_OBJECT_MEMORY || !readbuf)
3996 /* Don't bother for one word. */
3997 if (len < 3 * sizeof (long))
3998 return TARGET_XFER_EOF;
4000 /* We could keep this file open and cache it - possibly one per
4001 thread. That requires some juggling, but is even faster. */
4002 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
4003 ptid_get_pid (inferior_ptid));
4004 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
4006 return TARGET_XFER_EOF;
4008 /* If pread64 is available, use it. It's faster if the kernel
4009 supports it (only one syscall), and it's 64-bit safe even on
4010 32-bit platforms (for instance, SPARC debugging a SPARC64
4013 if (pread64 (fd, readbuf, len, offset) != len)
4015 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4024 return TARGET_XFER_EOF;
4028 return TARGET_XFER_OK;
4033 /* Enumerate spufs IDs for process PID. */
4035 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
4037 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4039 LONGEST written = 0;
4042 struct dirent *entry;
4044 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4045 dir = opendir (path);
4050 while ((entry = readdir (dir)) != NULL)
4056 fd = atoi (entry->d_name);
4060 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4061 if (stat (path, &st) != 0)
4063 if (!S_ISDIR (st.st_mode))
4066 if (statfs (path, &stfs) != 0)
4068 if (stfs.f_type != SPUFS_MAGIC)
4071 if (pos >= offset && pos + 4 <= offset + len)
4073 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4083 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4084 object type, using the /proc file system. */
4086 static enum target_xfer_status
4087 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4088 const char *annex, gdb_byte *readbuf,
4089 const gdb_byte *writebuf,
4090 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4095 int pid = ptid_get_pid (inferior_ptid);
4100 return TARGET_XFER_E_IO;
4103 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4106 return TARGET_XFER_E_IO;
4108 return TARGET_XFER_EOF;
4111 *xfered_len = (ULONGEST) l;
4112 return TARGET_XFER_OK;
4117 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4118 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4120 return TARGET_XFER_E_IO;
4123 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4126 return TARGET_XFER_EOF;
4130 ret = write (fd, writebuf, (size_t) len);
4132 ret = read (fd, readbuf, (size_t) len);
4137 return TARGET_XFER_E_IO;
4139 return TARGET_XFER_EOF;
4142 *xfered_len = (ULONGEST) ret;
4143 return TARGET_XFER_OK;
4148 /* Parse LINE as a signal set and add its set bits to SIGS. */
4151 add_line_to_sigset (const char *line, sigset_t *sigs)
4153 int len = strlen (line) - 1;
4157 if (line[len] != '\n')
4158 error (_("Could not parse signal set: %s"), line);
4166 if (*p >= '0' && *p <= '9')
4168 else if (*p >= 'a' && *p <= 'f')
4169 digit = *p - 'a' + 10;
4171 error (_("Could not parse signal set: %s"), line);
4176 sigaddset (sigs, signum + 1);
4178 sigaddset (sigs, signum + 2);
4180 sigaddset (sigs, signum + 3);
4182 sigaddset (sigs, signum + 4);
4188 /* Find process PID's pending signals from /proc/pid/status and set
4192 linux_proc_pending_signals (int pid, sigset_t *pending,
4193 sigset_t *blocked, sigset_t *ignored)
4196 char buffer[PATH_MAX], fname[PATH_MAX];
4197 struct cleanup *cleanup;
4199 sigemptyset (pending);
4200 sigemptyset (blocked);
4201 sigemptyset (ignored);
4202 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4203 procfile = gdb_fopen_cloexec (fname, "r");
4204 if (procfile == NULL)
4205 error (_("Could not open %s"), fname);
4206 cleanup = make_cleanup_fclose (procfile);
4208 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4210 /* Normal queued signals are on the SigPnd line in the status
4211 file. However, 2.6 kernels also have a "shared" pending
4212 queue for delivering signals to a thread group, so check for
4215 Unfortunately some Red Hat kernels include the shared pending
4216 queue but not the ShdPnd status field. */
4218 if (startswith (buffer, "SigPnd:\t"))
4219 add_line_to_sigset (buffer + 8, pending);
4220 else if (startswith (buffer, "ShdPnd:\t"))
4221 add_line_to_sigset (buffer + 8, pending);
4222 else if (startswith (buffer, "SigBlk:\t"))
4223 add_line_to_sigset (buffer + 8, blocked);
4224 else if (startswith (buffer, "SigIgn:\t"))
4225 add_line_to_sigset (buffer + 8, ignored);
4228 do_cleanups (cleanup);
4231 static enum target_xfer_status
4232 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4233 const char *annex, gdb_byte *readbuf,
4234 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4235 ULONGEST *xfered_len)
4237 gdb_assert (object == TARGET_OBJECT_OSDATA);
4239 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4240 if (*xfered_len == 0)
4241 return TARGET_XFER_EOF;
4243 return TARGET_XFER_OK;
4246 static enum target_xfer_status
4247 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4248 const char *annex, gdb_byte *readbuf,
4249 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4250 ULONGEST *xfered_len)
4252 enum target_xfer_status xfer;
4254 if (object == TARGET_OBJECT_AUXV)
4255 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4256 offset, len, xfered_len);
4258 if (object == TARGET_OBJECT_OSDATA)
4259 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4260 offset, len, xfered_len);
4262 if (object == TARGET_OBJECT_SPU)
4263 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4264 offset, len, xfered_len);
4266 /* GDB calculates all the addresses in possibly larget width of the address.
4267 Address width needs to be masked before its final use - either by
4268 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4270 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4272 if (object == TARGET_OBJECT_MEMORY)
4274 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4276 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4277 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4280 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4281 offset, len, xfered_len);
4282 if (xfer != TARGET_XFER_EOF)
4285 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4286 offset, len, xfered_len);
4290 cleanup_target_stop (void *arg)
4292 ptid_t *ptid = (ptid_t *) arg;
4294 gdb_assert (arg != NULL);
4297 target_resume (*ptid, 0, GDB_SIGNAL_0);
4300 static VEC(static_tracepoint_marker_p) *
4301 linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
4304 char s[IPA_CMD_BUF_SIZE];
4305 struct cleanup *old_chain;
4306 int pid = ptid_get_pid (inferior_ptid);
4307 VEC(static_tracepoint_marker_p) *markers = NULL;
4308 struct static_tracepoint_marker *marker = NULL;
4310 ptid_t ptid = ptid_build (pid, 0, 0);
4315 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4316 s[sizeof ("qTfSTM")] = 0;
4318 agent_run_command (pid, s, strlen (s) + 1);
4320 old_chain = make_cleanup (free_current_marker, &marker);
4321 make_cleanup (cleanup_target_stop, &ptid);
4326 marker = XCNEW (struct static_tracepoint_marker);
4330 parse_static_tracepoint_marker_definition (p, &p, marker);
4332 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4334 VEC_safe_push (static_tracepoint_marker_p,
4340 release_static_tracepoint_marker (marker);
4341 memset (marker, 0, sizeof (*marker));
4344 while (*p++ == ','); /* comma-separated list */
4346 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4347 s[sizeof ("qTsSTM")] = 0;
4348 agent_run_command (pid, s, strlen (s) + 1);
4352 do_cleanups (old_chain);
4357 /* Create a prototype generic GNU/Linux target. The client can override
4358 it with local methods. */
4361 linux_target_install_ops (struct target_ops *t)
4363 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4364 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4365 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4366 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4367 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4368 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4369 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4370 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4371 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4372 t->to_post_attach = linux_child_post_attach;
4373 t->to_follow_fork = linux_child_follow_fork;
4375 super_xfer_partial = t->to_xfer_partial;
4376 t->to_xfer_partial = linux_xfer_partial;
4378 t->to_static_tracepoint_markers_by_strid
4379 = linux_child_static_tracepoint_markers_by_strid;
4385 struct target_ops *t;
4387 t = inf_ptrace_target ();
4388 linux_target_install_ops (t);
4394 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4396 struct target_ops *t;
4398 t = inf_ptrace_trad_target (register_u_offset);
4399 linux_target_install_ops (t);
4404 /* target_is_async_p implementation. */
4407 linux_nat_is_async_p (struct target_ops *ops)
4409 return linux_is_async_p ();
4412 /* target_can_async_p implementation. */
4415 linux_nat_can_async_p (struct target_ops *ops)
4417 /* NOTE: palves 2008-03-21: We're only async when the user requests
4418 it explicitly with the "set target-async" command.
4419 Someday, linux will always be async. */
4420 return target_async_permitted;
4424 linux_nat_supports_non_stop (struct target_ops *self)
4429 /* True if we want to support multi-process. To be removed when GDB
4430 supports multi-exec. */
4432 int linux_multi_process = 1;
4435 linux_nat_supports_multi_process (struct target_ops *self)
4437 return linux_multi_process;
4441 linux_nat_supports_disable_randomization (struct target_ops *self)
4443 #ifdef HAVE_PERSONALITY
4450 static int async_terminal_is_ours = 1;
4452 /* target_terminal_inferior implementation.
4454 This is a wrapper around child_terminal_inferior to add async support. */
4457 linux_nat_terminal_inferior (struct target_ops *self)
4459 /* Like target_terminal_inferior, use target_can_async_p, not
4460 target_is_async_p, since at this point the target is not async
4461 yet. If it can async, then we know it will become async prior to
4463 if (!target_can_async_p ())
4465 /* Async mode is disabled. */
4466 child_terminal_inferior (self);
4470 child_terminal_inferior (self);
4472 /* Calls to target_terminal_*() are meant to be idempotent. */
4473 if (!async_terminal_is_ours)
4476 delete_file_handler (input_fd);
4477 async_terminal_is_ours = 0;
4481 /* target_terminal_ours implementation.
4483 This is a wrapper around child_terminal_ours to add async support (and
4484 implement the target_terminal_ours vs target_terminal_ours_for_output
4485 distinction). child_terminal_ours is currently no different than
4486 child_terminal_ours_for_output.
4487 We leave target_terminal_ours_for_output alone, leaving it to
4488 child_terminal_ours_for_output. */
4491 linux_nat_terminal_ours (struct target_ops *self)
4493 /* GDB should never give the terminal to the inferior if the
4494 inferior is running in the background (run&, continue&, etc.),
4495 but claiming it sure should. */
4496 child_terminal_ours (self);
4498 if (async_terminal_is_ours)
4501 clear_sigint_trap ();
4502 add_file_handler (input_fd, stdin_event_handler, 0);
4503 async_terminal_is_ours = 1;
4506 static void (*async_client_callback) (enum inferior_event_type event_type,
4508 static void *async_client_context;
4510 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4511 so we notice when any child changes state, and notify the
4512 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4513 above to wait for the arrival of a SIGCHLD. */
4516 sigchld_handler (int signo)
4518 int old_errno = errno;
4520 if (debug_linux_nat)
4521 ui_file_write_async_safe (gdb_stdlog,
4522 "sigchld\n", sizeof ("sigchld\n") - 1);
4524 if (signo == SIGCHLD
4525 && linux_nat_event_pipe[0] != -1)
4526 async_file_mark (); /* Let the event loop know that there are
4527 events to handle. */
4532 /* Callback registered with the target events file descriptor. */
4535 handle_target_event (int error, gdb_client_data client_data)
4537 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4540 /* Create/destroy the target events pipe. Returns previous state. */
4543 linux_async_pipe (int enable)
4545 int previous = linux_is_async_p ();
4547 if (previous != enable)
4551 /* Block child signals while we create/destroy the pipe, as
4552 their handler writes to it. */
4553 block_child_signals (&prev_mask);
4557 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4558 internal_error (__FILE__, __LINE__,
4559 "creating event pipe failed.");
4561 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4562 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4566 close (linux_nat_event_pipe[0]);
4567 close (linux_nat_event_pipe[1]);
4568 linux_nat_event_pipe[0] = -1;
4569 linux_nat_event_pipe[1] = -1;
4572 restore_child_signals_mask (&prev_mask);
4578 /* target_async implementation. */
4581 linux_nat_async (struct target_ops *ops,
4582 void (*callback) (enum inferior_event_type event_type,
4586 if (callback != NULL)
4588 async_client_callback = callback;
4589 async_client_context = context;
4590 if (!linux_async_pipe (1))
4592 add_file_handler (linux_nat_event_pipe[0],
4593 handle_target_event, NULL);
4594 /* There may be pending events to handle. Tell the event loop
4601 async_client_callback = callback;
4602 async_client_context = context;
4603 delete_file_handler (linux_nat_event_pipe[0]);
4604 linux_async_pipe (0);
4609 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4613 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4617 if (debug_linux_nat)
4618 fprintf_unfiltered (gdb_stdlog,
4619 "LNSL: running -> suspending %s\n",
4620 target_pid_to_str (lwp->ptid));
4623 if (lwp->last_resume_kind == resume_stop)
4625 if (debug_linux_nat)
4626 fprintf_unfiltered (gdb_stdlog,
4627 "linux-nat: already stopping LWP %ld at "
4629 ptid_get_lwp (lwp->ptid));
4633 stop_callback (lwp, NULL);
4634 lwp->last_resume_kind = resume_stop;
4638 /* Already known to be stopped; do nothing. */
4640 if (debug_linux_nat)
4642 if (find_thread_ptid (lwp->ptid)->stop_requested)
4643 fprintf_unfiltered (gdb_stdlog,
4644 "LNSL: already stopped/stop_requested %s\n",
4645 target_pid_to_str (lwp->ptid));
4647 fprintf_unfiltered (gdb_stdlog,
4648 "LNSL: already stopped/no "
4649 "stop_requested yet %s\n",
4650 target_pid_to_str (lwp->ptid));
4657 linux_nat_stop (struct target_ops *self, ptid_t ptid)
4660 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4662 linux_ops->to_stop (linux_ops, ptid);
4666 linux_nat_close (struct target_ops *self)
4668 /* Unregister from the event loop. */
4669 if (linux_nat_is_async_p (self))
4670 linux_nat_async (self, NULL, NULL);
4672 if (linux_ops->to_close)
4673 linux_ops->to_close (linux_ops);
4678 /* When requests are passed down from the linux-nat layer to the
4679 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4680 used. The address space pointer is stored in the inferior object,
4681 but the common code that is passed such ptid can't tell whether
4682 lwpid is a "main" process id or not (it assumes so). We reverse
4683 look up the "main" process id from the lwp here. */
4685 static struct address_space *
4686 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4688 struct lwp_info *lwp;
4689 struct inferior *inf;
4692 if (ptid_get_lwp (ptid) == 0)
4694 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4696 lwp = find_lwp_pid (ptid);
4697 pid = ptid_get_pid (lwp->ptid);
4701 /* A (pid,lwpid,0) ptid. */
4702 pid = ptid_get_pid (ptid);
4705 inf = find_inferior_pid (pid);
4706 gdb_assert (inf != NULL);
4710 /* Return the cached value of the processor core for thread PTID. */
4713 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4715 struct lwp_info *info = find_lwp_pid (ptid);
4723 linux_nat_add_target (struct target_ops *t)
4725 /* Save the provided single-threaded target. We save this in a separate
4726 variable because another target we've inherited from (e.g. inf-ptrace)
4727 may have saved a pointer to T; we want to use it for the final
4728 process stratum target. */
4729 linux_ops_saved = *t;
4730 linux_ops = &linux_ops_saved;
4732 /* Override some methods for multithreading. */
4733 t->to_create_inferior = linux_nat_create_inferior;
4734 t->to_attach = linux_nat_attach;
4735 t->to_detach = linux_nat_detach;
4736 t->to_resume = linux_nat_resume;
4737 t->to_wait = linux_nat_wait;
4738 t->to_pass_signals = linux_nat_pass_signals;
4739 t->to_xfer_partial = linux_nat_xfer_partial;
4740 t->to_kill = linux_nat_kill;
4741 t->to_mourn_inferior = linux_nat_mourn_inferior;
4742 t->to_thread_alive = linux_nat_thread_alive;
4743 t->to_pid_to_str = linux_nat_pid_to_str;
4744 t->to_thread_name = linux_nat_thread_name;
4745 t->to_has_thread_control = tc_schedlock;
4746 t->to_thread_address_space = linux_nat_thread_address_space;
4747 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4748 t->to_stopped_data_address = linux_nat_stopped_data_address;
4749 t->to_stopped_by_sw_breakpoint = linux_nat_stopped_by_sw_breakpoint;
4750 t->to_supports_stopped_by_sw_breakpoint = linux_nat_supports_stopped_by_sw_breakpoint;
4751 t->to_stopped_by_hw_breakpoint = linux_nat_stopped_by_hw_breakpoint;
4752 t->to_supports_stopped_by_hw_breakpoint = linux_nat_supports_stopped_by_hw_breakpoint;
4754 t->to_can_async_p = linux_nat_can_async_p;
4755 t->to_is_async_p = linux_nat_is_async_p;
4756 t->to_supports_non_stop = linux_nat_supports_non_stop;
4757 t->to_async = linux_nat_async;
4758 t->to_terminal_inferior = linux_nat_terminal_inferior;
4759 t->to_terminal_ours = linux_nat_terminal_ours;
4761 super_close = t->to_close;
4762 t->to_close = linux_nat_close;
4764 /* Methods for non-stop support. */
4765 t->to_stop = linux_nat_stop;
4767 t->to_supports_multi_process = linux_nat_supports_multi_process;
4769 t->to_supports_disable_randomization
4770 = linux_nat_supports_disable_randomization;
4772 t->to_core_of_thread = linux_nat_core_of_thread;
4774 /* We don't change the stratum; this target will sit at
4775 process_stratum and thread_db will set at thread_stratum. This
4776 is a little strange, since this is a multi-threaded-capable
4777 target, but we want to be on the stack below thread_db, and we
4778 also want to be used for single-threaded processes. */
4783 /* Register a method to call whenever a new thread is attached. */
4785 linux_nat_set_new_thread (struct target_ops *t,
4786 void (*new_thread) (struct lwp_info *))
4788 /* Save the pointer. We only support a single registered instance
4789 of the GNU/Linux native target, so we do not need to map this to
4791 linux_nat_new_thread = new_thread;
4794 /* See declaration in linux-nat.h. */
4797 linux_nat_set_new_fork (struct target_ops *t,
4798 linux_nat_new_fork_ftype *new_fork)
4800 /* Save the pointer. */
4801 linux_nat_new_fork = new_fork;
4804 /* See declaration in linux-nat.h. */
4807 linux_nat_set_forget_process (struct target_ops *t,
4808 linux_nat_forget_process_ftype *fn)
4810 /* Save the pointer. */
4811 linux_nat_forget_process_hook = fn;
4814 /* See declaration in linux-nat.h. */
4817 linux_nat_forget_process (pid_t pid)
4819 if (linux_nat_forget_process_hook != NULL)
4820 linux_nat_forget_process_hook (pid);
4823 /* Register a method that converts a siginfo object between the layout
4824 that ptrace returns, and the layout in the architecture of the
4827 linux_nat_set_siginfo_fixup (struct target_ops *t,
4828 int (*siginfo_fixup) (siginfo_t *,
4832 /* Save the pointer. */
4833 linux_nat_siginfo_fixup = siginfo_fixup;
4836 /* Register a method to call prior to resuming a thread. */
4839 linux_nat_set_prepare_to_resume (struct target_ops *t,
4840 void (*prepare_to_resume) (struct lwp_info *))
4842 /* Save the pointer. */
4843 linux_nat_prepare_to_resume = prepare_to_resume;
4846 /* See linux-nat.h. */
4849 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4853 pid = ptid_get_lwp (ptid);
4855 pid = ptid_get_pid (ptid);
4858 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4861 memset (siginfo, 0, sizeof (*siginfo));
4867 /* Provide a prototype to silence -Wmissing-prototypes. */
4868 extern initialize_file_ftype _initialize_linux_nat;
4871 _initialize_linux_nat (void)
4873 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4874 &debug_linux_nat, _("\
4875 Set debugging of GNU/Linux lwp module."), _("\
4876 Show debugging of GNU/Linux lwp module."), _("\
4877 Enables printf debugging output."),
4879 show_debug_linux_nat,
4880 &setdebuglist, &showdebuglist);
4882 /* Save this mask as the default. */
4883 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4885 /* Install a SIGCHLD handler. */
4886 sigchld_action.sa_handler = sigchld_handler;
4887 sigemptyset (&sigchld_action.sa_mask);
4888 sigchld_action.sa_flags = SA_RESTART;
4890 /* Make it the default. */
4891 sigaction (SIGCHLD, &sigchld_action, NULL);
4893 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4894 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
4895 sigdelset (&suspend_mask, SIGCHLD);
4897 sigemptyset (&blocked_mask);
4899 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
4900 support read-only process state. */
4901 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
4902 | PTRACE_O_TRACEVFORKDONE
4903 | PTRACE_O_TRACEVFORK
4904 | PTRACE_O_TRACEFORK
4905 | PTRACE_O_TRACEEXEC);
4909 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4910 the GNU/Linux Threads library and therefore doesn't really belong
4913 /* Read variable NAME in the target and return its value if found.
4914 Otherwise return zero. It is assumed that the type of the variable
4918 get_signo (const char *name)
4920 struct bound_minimal_symbol ms;
4923 ms = lookup_minimal_symbol (name, NULL, NULL);
4924 if (ms.minsym == NULL)
4927 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
4928 sizeof (signo)) != 0)
4934 /* Return the set of signals used by the threads library in *SET. */
4937 lin_thread_get_thread_signals (sigset_t *set)
4939 struct sigaction action;
4940 int restart, cancel;
4942 sigemptyset (&blocked_mask);
4945 restart = get_signo ("__pthread_sig_restart");
4946 cancel = get_signo ("__pthread_sig_cancel");
4948 /* LinuxThreads normally uses the first two RT signals, but in some legacy
4949 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
4950 not provide any way for the debugger to query the signal numbers -
4951 fortunately they don't change! */
4954 restart = __SIGRTMIN;
4957 cancel = __SIGRTMIN + 1;
4959 sigaddset (set, restart);
4960 sigaddset (set, cancel);
4962 /* The GNU/Linux Threads library makes terminating threads send a
4963 special "cancel" signal instead of SIGCHLD. Make sure we catch
4964 those (to prevent them from terminating GDB itself, which is
4965 likely to be their default action) and treat them the same way as
4968 action.sa_handler = sigchld_handler;
4969 sigemptyset (&action.sa_mask);
4970 action.sa_flags = SA_RESTART;
4971 sigaction (cancel, &action, NULL);
4973 /* We block the "cancel" signal throughout this code ... */
4974 sigaddset (&blocked_mask, cancel);
4975 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
4977 /* ... except during a sigsuspend. */
4978 sigdelset (&suspend_mask, cancel);