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 int parent_pid, child_pid;
392 has_vforked = (inferior_thread ()->pending_follow.kind
393 == TARGET_WAITKIND_VFORKED);
394 parent_pid = ptid_get_lwp (inferior_ptid);
396 parent_pid = ptid_get_pid (inferior_ptid);
398 = ptid_get_pid (inferior_thread ()->pending_follow.value.related_pid);
401 /* We're already attached to the parent, by default. */
402 old_chain = save_inferior_ptid ();
403 inferior_ptid = ptid_build (child_pid, child_pid, 0);
404 child_lp = add_lwp (inferior_ptid);
405 child_lp->stopped = 1;
406 child_lp->last_resume_kind = resume_stop;
408 /* Detach new forked process? */
411 make_cleanup (delete_lwp_cleanup, child_lp);
413 if (linux_nat_prepare_to_resume != NULL)
414 linux_nat_prepare_to_resume (child_lp);
416 /* When debugging an inferior in an architecture that supports
417 hardware single stepping on a kernel without commit
418 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
419 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
420 set if the parent process had them set.
421 To work around this, single step the child process
422 once before detaching to clear the flags. */
424 if (!gdbarch_software_single_step_p (target_thread_architecture
427 linux_disable_event_reporting (child_pid);
428 if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
429 perror_with_name (_("Couldn't do single step"));
430 if (my_waitpid (child_pid, &status, 0) < 0)
431 perror_with_name (_("Couldn't wait vfork process"));
434 if (WIFSTOPPED (status))
438 signo = WSTOPSIG (status);
440 && !signal_pass_state (gdb_signal_from_host (signo)))
442 ptrace (PTRACE_DETACH, child_pid, 0, signo);
445 /* Resets value of inferior_ptid to parent ptid. */
446 do_cleanups (old_chain);
450 /* Let the thread_db layer learn about this new process. */
451 check_for_thread_db ();
454 do_cleanups (old_chain);
458 struct lwp_info *parent_lp;
460 parent_lp = find_lwp_pid (pid_to_ptid (parent_pid));
461 gdb_assert (linux_supports_tracefork () >= 0);
463 if (linux_supports_tracevforkdone ())
466 fprintf_unfiltered (gdb_stdlog,
467 "LCFF: waiting for VFORK_DONE on %d\n",
469 parent_lp->stopped = 1;
471 /* We'll handle the VFORK_DONE event like any other
472 event, in target_wait. */
476 /* We can't insert breakpoints until the child has
477 finished with the shared memory region. We need to
478 wait until that happens. Ideal would be to just
480 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
481 - waitpid (parent_pid, &status, __WALL);
482 However, most architectures can't handle a syscall
483 being traced on the way out if it wasn't traced on
486 We might also think to loop, continuing the child
487 until it exits or gets a SIGTRAP. One problem is
488 that the child might call ptrace with PTRACE_TRACEME.
490 There's no simple and reliable way to figure out when
491 the vforked child will be done with its copy of the
492 shared memory. We could step it out of the syscall,
493 two instructions, let it go, and then single-step the
494 parent once. When we have hardware single-step, this
495 would work; with software single-step it could still
496 be made to work but we'd have to be able to insert
497 single-step breakpoints in the child, and we'd have
498 to insert -just- the single-step breakpoint in the
499 parent. Very awkward.
501 In the end, the best we can do is to make sure it
502 runs for a little while. Hopefully it will be out of
503 range of any breakpoints we reinsert. Usually this
504 is only the single-step breakpoint at vfork's return
508 fprintf_unfiltered (gdb_stdlog,
509 "LCFF: no VFORK_DONE "
510 "support, sleeping a bit\n");
514 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
515 and leave it pending. The next linux_nat_resume call
516 will notice a pending event, and bypasses actually
517 resuming the inferior. */
518 parent_lp->status = 0;
519 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
520 parent_lp->stopped = 1;
522 /* If we're in async mode, need to tell the event loop
523 there's something here to process. */
524 if (target_is_async_p ())
531 struct lwp_info *child_lp;
533 child_lp = add_lwp (inferior_ptid);
534 child_lp->stopped = 1;
535 child_lp->last_resume_kind = resume_stop;
537 /* Let the thread_db layer learn about this new process. */
538 check_for_thread_db ();
546 linux_child_insert_fork_catchpoint (struct target_ops *self, int pid)
548 return !linux_supports_tracefork ();
552 linux_child_remove_fork_catchpoint (struct target_ops *self, int pid)
558 linux_child_insert_vfork_catchpoint (struct target_ops *self, int pid)
560 return !linux_supports_tracefork ();
564 linux_child_remove_vfork_catchpoint (struct target_ops *self, int pid)
570 linux_child_insert_exec_catchpoint (struct target_ops *self, int pid)
572 return !linux_supports_tracefork ();
576 linux_child_remove_exec_catchpoint (struct target_ops *self, int pid)
582 linux_child_set_syscall_catchpoint (struct target_ops *self,
583 int pid, int needed, int any_count,
584 int table_size, int *table)
586 if (!linux_supports_tracesysgood ())
589 /* On GNU/Linux, we ignore the arguments. It means that we only
590 enable the syscall catchpoints, but do not disable them.
592 Also, we do not use the `table' information because we do not
593 filter system calls here. We let GDB do the logic for us. */
597 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
598 are processes sharing the same VM space. A multi-threaded process
599 is basically a group of such processes. However, such a grouping
600 is almost entirely a user-space issue; the kernel doesn't enforce
601 such a grouping at all (this might change in the future). In
602 general, we'll rely on the threads library (i.e. the GNU/Linux
603 Threads library) to provide such a grouping.
605 It is perfectly well possible to write a multi-threaded application
606 without the assistance of a threads library, by using the clone
607 system call directly. This module should be able to give some
608 rudimentary support for debugging such applications if developers
609 specify the CLONE_PTRACE flag in the clone system call, and are
610 using the Linux kernel 2.4 or above.
612 Note that there are some peculiarities in GNU/Linux that affect
615 - In general one should specify the __WCLONE flag to waitpid in
616 order to make it report events for any of the cloned processes
617 (and leave it out for the initial process). However, if a cloned
618 process has exited the exit status is only reported if the
619 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
620 we cannot use it since GDB must work on older systems too.
622 - When a traced, cloned process exits and is waited for by the
623 debugger, the kernel reassigns it to the original parent and
624 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
625 library doesn't notice this, which leads to the "zombie problem":
626 When debugged a multi-threaded process that spawns a lot of
627 threads will run out of processes, even if the threads exit,
628 because the "zombies" stay around. */
630 /* List of known LWPs. */
631 struct lwp_info *lwp_list;
634 /* Original signal mask. */
635 static sigset_t normal_mask;
637 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
638 _initialize_linux_nat. */
639 static sigset_t suspend_mask;
641 /* Signals to block to make that sigsuspend work. */
642 static sigset_t blocked_mask;
644 /* SIGCHLD action. */
645 struct sigaction sigchld_action;
647 /* Block child signals (SIGCHLD and linux threads signals), and store
648 the previous mask in PREV_MASK. */
651 block_child_signals (sigset_t *prev_mask)
653 /* Make sure SIGCHLD is blocked. */
654 if (!sigismember (&blocked_mask, SIGCHLD))
655 sigaddset (&blocked_mask, SIGCHLD);
657 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
660 /* Restore child signals mask, previously returned by
661 block_child_signals. */
664 restore_child_signals_mask (sigset_t *prev_mask)
666 sigprocmask (SIG_SETMASK, prev_mask, NULL);
669 /* Mask of signals to pass directly to the inferior. */
670 static sigset_t pass_mask;
672 /* Update signals to pass to the inferior. */
674 linux_nat_pass_signals (struct target_ops *self,
675 int numsigs, unsigned char *pass_signals)
679 sigemptyset (&pass_mask);
681 for (signo = 1; signo < NSIG; signo++)
683 int target_signo = gdb_signal_from_host (signo);
684 if (target_signo < numsigs && pass_signals[target_signo])
685 sigaddset (&pass_mask, signo);
691 /* Prototypes for local functions. */
692 static int stop_wait_callback (struct lwp_info *lp, void *data);
693 static int linux_thread_alive (ptid_t ptid);
694 static char *linux_child_pid_to_exec_file (struct target_ops *self, int pid);
695 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
699 /* Destroy and free LP. */
702 lwp_free (struct lwp_info *lp)
704 xfree (lp->arch_private);
708 /* Remove all LWPs belong to PID from the lwp list. */
711 purge_lwp_list (int pid)
713 struct lwp_info *lp, *lpprev, *lpnext;
717 for (lp = lwp_list; lp; lp = lpnext)
721 if (ptid_get_pid (lp->ptid) == pid)
726 lpprev->next = lp->next;
735 /* Add the LWP specified by PTID to the list. PTID is the first LWP
736 in the process. Return a pointer to the structure describing the
739 This differs from add_lwp in that we don't let the arch specific
740 bits know about this new thread. Current clients of this callback
741 take the opportunity to install watchpoints in the new thread, and
742 we shouldn't do that for the first thread. If we're spawning a
743 child ("run"), the thread executes the shell wrapper first, and we
744 shouldn't touch it until it execs the program we want to debug.
745 For "attach", it'd be okay to call the callback, but it's not
746 necessary, because watchpoints can't yet have been inserted into
749 static struct lwp_info *
750 add_initial_lwp (ptid_t ptid)
754 gdb_assert (ptid_lwp_p (ptid));
756 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
758 memset (lp, 0, sizeof (struct lwp_info));
760 lp->last_resume_kind = resume_continue;
761 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
772 /* Add the LWP specified by PID to the list. Return a pointer to the
773 structure describing the new LWP. The LWP should already be
776 static struct lwp_info *
777 add_lwp (ptid_t ptid)
781 lp = add_initial_lwp (ptid);
783 /* Let the arch specific bits know about this new thread. Current
784 clients of this callback take the opportunity to install
785 watchpoints in the new thread. We don't do this for the first
786 thread though. See add_initial_lwp. */
787 if (linux_nat_new_thread != NULL)
788 linux_nat_new_thread (lp);
793 /* Remove the LWP specified by PID from the list. */
796 delete_lwp (ptid_t ptid)
798 struct lwp_info *lp, *lpprev;
802 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
803 if (ptid_equal (lp->ptid, ptid))
810 lpprev->next = lp->next;
817 /* Return a pointer to the structure describing the LWP corresponding
818 to PID. If no corresponding LWP could be found, return NULL. */
820 static struct lwp_info *
821 find_lwp_pid (ptid_t ptid)
826 if (ptid_lwp_p (ptid))
827 lwp = ptid_get_lwp (ptid);
829 lwp = ptid_get_pid (ptid);
831 for (lp = lwp_list; lp; lp = lp->next)
832 if (lwp == ptid_get_lwp (lp->ptid))
838 /* Call CALLBACK with its second argument set to DATA for every LWP in
839 the list. If CALLBACK returns 1 for a particular LWP, return a
840 pointer to the structure describing that LWP immediately.
841 Otherwise return NULL. */
844 iterate_over_lwps (ptid_t filter,
845 int (*callback) (struct lwp_info *, void *),
848 struct lwp_info *lp, *lpnext;
850 for (lp = lwp_list; lp; lp = lpnext)
854 if (ptid_match (lp->ptid, filter))
856 if ((*callback) (lp, data))
864 /* Update our internal state when changing from one checkpoint to
865 another indicated by NEW_PTID. We can only switch single-threaded
866 applications, so we only create one new LWP, and the previous list
870 linux_nat_switch_fork (ptid_t new_ptid)
874 purge_lwp_list (ptid_get_pid (inferior_ptid));
876 lp = add_lwp (new_ptid);
879 /* This changes the thread's ptid while preserving the gdb thread
880 num. Also changes the inferior pid, while preserving the
882 thread_change_ptid (inferior_ptid, new_ptid);
884 /* We've just told GDB core that the thread changed target id, but,
885 in fact, it really is a different thread, with different register
887 registers_changed ();
890 /* Handle the exit of a single thread LP. */
893 exit_lwp (struct lwp_info *lp)
895 struct thread_info *th = find_thread_ptid (lp->ptid);
899 if (print_thread_events)
900 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
902 delete_thread (lp->ptid);
905 delete_lwp (lp->ptid);
908 /* Wait for the LWP specified by LP, which we have just attached to.
909 Returns a wait status for that LWP, to cache. */
912 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
915 pid_t new_pid, pid = ptid_get_lwp (ptid);
918 if (linux_proc_pid_is_stopped (pid))
921 fprintf_unfiltered (gdb_stdlog,
922 "LNPAW: Attaching to a stopped process\n");
924 /* The process is definitely stopped. It is in a job control
925 stop, unless the kernel predates the TASK_STOPPED /
926 TASK_TRACED distinction, in which case it might be in a
927 ptrace stop. Make sure it is in a ptrace stop; from there we
928 can kill it, signal it, et cetera.
930 First make sure there is a pending SIGSTOP. Since we are
931 already attached, the process can not transition from stopped
932 to running without a PTRACE_CONT; so we know this signal will
933 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
934 probably already in the queue (unless this kernel is old
935 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
936 is not an RT signal, it can only be queued once. */
937 kill_lwp (pid, SIGSTOP);
939 /* Finally, resume the stopped process. This will deliver the SIGSTOP
940 (or a higher priority signal, just like normal PTRACE_ATTACH). */
941 ptrace (PTRACE_CONT, pid, 0, 0);
944 /* Make sure the initial process is stopped. The user-level threads
945 layer might want to poke around in the inferior, and that won't
946 work if things haven't stabilized yet. */
947 new_pid = my_waitpid (pid, &status, 0);
948 if (new_pid == -1 && errno == ECHILD)
951 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
953 /* Try again with __WCLONE to check cloned processes. */
954 new_pid = my_waitpid (pid, &status, __WCLONE);
958 gdb_assert (pid == new_pid);
960 if (!WIFSTOPPED (status))
962 /* The pid we tried to attach has apparently just exited. */
964 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
965 pid, status_to_str (status));
969 if (WSTOPSIG (status) != SIGSTOP)
973 fprintf_unfiltered (gdb_stdlog,
974 "LNPAW: Received %s after attaching\n",
975 status_to_str (status));
981 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
982 the new LWP could not be attached, or 1 if we're already auto
983 attached to this thread, but haven't processed the
984 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
985 its existance, without considering it an error. */
988 lin_lwp_attach_lwp (ptid_t ptid)
993 gdb_assert (ptid_lwp_p (ptid));
995 lp = find_lwp_pid (ptid);
996 lwpid = ptid_get_lwp (ptid);
998 /* We assume that we're already attached to any LWP that is already
999 in our list of LWPs. If we're not seeing exit events from threads
1000 and we've had PID wraparound since we last tried to stop all threads,
1001 this assumption might be wrong; fortunately, this is very unlikely
1005 int status, cloned = 0, signalled = 0;
1007 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1009 if (linux_supports_tracefork ())
1011 /* If we haven't stopped all threads when we get here,
1012 we may have seen a thread listed in thread_db's list,
1013 but not processed the PTRACE_EVENT_CLONE yet. If
1014 that's the case, ignore this new thread, and let
1015 normal event handling discover it later. */
1016 if (in_pid_list_p (stopped_pids, lwpid))
1018 /* We've already seen this thread stop, but we
1019 haven't seen the PTRACE_EVENT_CLONE extended
1021 if (debug_linux_nat)
1022 fprintf_unfiltered (gdb_stdlog,
1023 "LLAL: attach failed, but already seen "
1024 "this thread %s stop\n",
1025 target_pid_to_str (ptid));
1033 if (debug_linux_nat)
1034 fprintf_unfiltered (gdb_stdlog,
1035 "LLAL: attach failed, and haven't seen "
1036 "this thread %s stop yet\n",
1037 target_pid_to_str (ptid));
1039 /* We may or may not be attached to the LWP already.
1040 Try waitpid on it. If that errors, we're not
1041 attached to the LWP yet. Otherwise, we're
1042 already attached. */
1043 gdb_assert (lwpid > 0);
1044 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1045 if (new_pid == -1 && errno == ECHILD)
1046 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1051 /* The child hasn't stopped for its initial
1052 SIGSTOP stop yet. */
1053 if (debug_linux_nat)
1054 fprintf_unfiltered (gdb_stdlog,
1055 "LLAL: child hasn't "
1058 else if (WIFSTOPPED (status))
1060 if (debug_linux_nat)
1061 fprintf_unfiltered (gdb_stdlog,
1062 "LLAL: adding to stopped_pids\n");
1063 add_to_pid_list (&stopped_pids, lwpid, status);
1070 /* If we fail to attach to the thread, issue a warning,
1071 but continue. One way this can happen is if thread
1072 creation is interrupted; as of Linux kernel 2.6.19, a
1073 bug may place threads in the thread list and then fail
1075 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1076 safe_strerror (errno));
1080 if (debug_linux_nat)
1081 fprintf_unfiltered (gdb_stdlog,
1082 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1083 target_pid_to_str (ptid));
1085 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1086 if (!WIFSTOPPED (status))
1089 lp = add_lwp (ptid);
1091 lp->last_resume_kind = resume_stop;
1092 lp->cloned = cloned;
1093 lp->signalled = signalled;
1094 if (WSTOPSIG (status) != SIGSTOP)
1097 lp->status = status;
1100 target_post_attach (ptid_get_lwp (lp->ptid));
1102 if (debug_linux_nat)
1104 fprintf_unfiltered (gdb_stdlog,
1105 "LLAL: waitpid %s received %s\n",
1106 target_pid_to_str (ptid),
1107 status_to_str (status));
1115 linux_nat_create_inferior (struct target_ops *ops,
1116 char *exec_file, char *allargs, char **env,
1119 struct cleanup *restore_personality
1120 = maybe_disable_address_space_randomization (disable_randomization);
1122 /* The fork_child mechanism is synchronous and calls target_wait, so
1123 we have to mask the async mode. */
1125 /* Make sure we report all signals during startup. */
1126 linux_nat_pass_signals (ops, 0, NULL);
1128 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1130 do_cleanups (restore_personality);
1133 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1134 already attached. Returns true if a new LWP is found, false
1138 attach_proc_task_lwp_callback (ptid_t ptid)
1140 struct lwp_info *lp;
1142 /* Ignore LWPs we're already attached to. */
1143 lp = find_lwp_pid (ptid);
1146 int lwpid = ptid_get_lwp (ptid);
1148 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1152 /* Be quiet if we simply raced with the thread exiting.
1153 EPERM is returned if the thread's task still exists, and
1154 is marked as exited or zombie, as well as other
1155 conditions, so in that case, confirm the status in
1156 /proc/PID/status. */
1158 || (err == EPERM && linux_proc_pid_is_gone (lwpid)))
1160 if (debug_linux_nat)
1162 fprintf_unfiltered (gdb_stdlog,
1163 "Cannot attach to lwp %d: "
1164 "thread is gone (%d: %s)\n",
1165 lwpid, err, safe_strerror (err));
1170 warning (_("Cannot attach to lwp %d: %s"),
1172 linux_ptrace_attach_fail_reason_string (ptid,
1178 if (debug_linux_nat)
1179 fprintf_unfiltered (gdb_stdlog,
1180 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1181 target_pid_to_str (ptid));
1183 lp = add_lwp (ptid);
1186 /* The next time we wait for this LWP we'll see a SIGSTOP as
1187 PTRACE_ATTACH brings it to a halt. */
1190 /* We need to wait for a stop before being able to make the
1191 next ptrace call on this LWP. */
1192 lp->must_set_ptrace_flags = 1;
1201 linux_nat_attach (struct target_ops *ops, const char *args, int from_tty)
1203 struct lwp_info *lp;
1206 volatile struct gdb_exception ex;
1208 /* Make sure we report all signals during attach. */
1209 linux_nat_pass_signals (ops, 0, NULL);
1211 TRY_CATCH (ex, RETURN_MASK_ERROR)
1213 linux_ops->to_attach (ops, args, from_tty);
1217 pid_t pid = parse_pid_to_attach (args);
1218 struct buffer buffer;
1219 char *message, *buffer_s;
1221 message = xstrdup (ex.message);
1222 make_cleanup (xfree, message);
1224 buffer_init (&buffer);
1225 linux_ptrace_attach_fail_reason (pid, &buffer);
1227 buffer_grow_str0 (&buffer, "");
1228 buffer_s = buffer_finish (&buffer);
1229 make_cleanup (xfree, buffer_s);
1231 if (*buffer_s != '\0')
1232 throw_error (ex.error, "warning: %s\n%s", buffer_s, message);
1234 throw_error (ex.error, "%s", message);
1237 /* The ptrace base target adds the main thread with (pid,0,0)
1238 format. Decorate it with lwp info. */
1239 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1240 ptid_get_pid (inferior_ptid),
1242 thread_change_ptid (inferior_ptid, ptid);
1244 /* Add the initial process as the first LWP to the list. */
1245 lp = add_initial_lwp (ptid);
1247 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1249 if (!WIFSTOPPED (status))
1251 if (WIFEXITED (status))
1253 int exit_code = WEXITSTATUS (status);
1255 target_terminal_ours ();
1256 target_mourn_inferior ();
1258 error (_("Unable to attach: program exited normally."));
1260 error (_("Unable to attach: program exited with code %d."),
1263 else if (WIFSIGNALED (status))
1265 enum gdb_signal signo;
1267 target_terminal_ours ();
1268 target_mourn_inferior ();
1270 signo = gdb_signal_from_host (WTERMSIG (status));
1271 error (_("Unable to attach: program terminated with signal "
1273 gdb_signal_to_name (signo),
1274 gdb_signal_to_string (signo));
1277 internal_error (__FILE__, __LINE__,
1278 _("unexpected status %d for PID %ld"),
1279 status, (long) ptid_get_lwp (ptid));
1284 /* Save the wait status to report later. */
1286 if (debug_linux_nat)
1287 fprintf_unfiltered (gdb_stdlog,
1288 "LNA: waitpid %ld, saving status %s\n",
1289 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1291 lp->status = status;
1293 /* We must attach to every LWP. If /proc is mounted, use that to
1294 find them now. The inferior may be using raw clone instead of
1295 using pthreads. But even if it is using pthreads, thread_db
1296 walks structures in the inferior's address space to find the list
1297 of threads/LWPs, and those structures may well be corrupted.
1298 Note that once thread_db is loaded, we'll still use it to list
1299 threads and associate pthread info with each LWP. */
1300 linux_proc_attach_tgid_threads (ptid_get_pid (lp->ptid),
1301 attach_proc_task_lwp_callback);
1303 if (target_can_async_p ())
1304 target_async (inferior_event_handler, 0);
1307 /* Get pending status of LP. */
1309 get_pending_status (struct lwp_info *lp, int *status)
1311 enum gdb_signal signo = GDB_SIGNAL_0;
1313 /* If we paused threads momentarily, we may have stored pending
1314 events in lp->status or lp->waitstatus (see stop_wait_callback),
1315 and GDB core hasn't seen any signal for those threads.
1316 Otherwise, the last signal reported to the core is found in the
1317 thread object's stop_signal.
1319 There's a corner case that isn't handled here at present. Only
1320 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1321 stop_signal make sense as a real signal to pass to the inferior.
1322 Some catchpoint related events, like
1323 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1324 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1325 those traps are debug API (ptrace in our case) related and
1326 induced; the inferior wouldn't see them if it wasn't being
1327 traced. Hence, we should never pass them to the inferior, even
1328 when set to pass state. Since this corner case isn't handled by
1329 infrun.c when proceeding with a signal, for consistency, neither
1330 do we handle it here (or elsewhere in the file we check for
1331 signal pass state). Normally SIGTRAP isn't set to pass state, so
1332 this is really a corner case. */
1334 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1335 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1336 else if (lp->status)
1337 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1338 else if (non_stop && !is_executing (lp->ptid))
1340 struct thread_info *tp = find_thread_ptid (lp->ptid);
1342 signo = tp->suspend.stop_signal;
1346 struct target_waitstatus last;
1349 get_last_target_status (&last_ptid, &last);
1351 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1353 struct thread_info *tp = find_thread_ptid (lp->ptid);
1355 signo = tp->suspend.stop_signal;
1361 if (signo == GDB_SIGNAL_0)
1363 if (debug_linux_nat)
1364 fprintf_unfiltered (gdb_stdlog,
1365 "GPT: lwp %s has no pending signal\n",
1366 target_pid_to_str (lp->ptid));
1368 else if (!signal_pass_state (signo))
1370 if (debug_linux_nat)
1371 fprintf_unfiltered (gdb_stdlog,
1372 "GPT: lwp %s had signal %s, "
1373 "but it is in no pass state\n",
1374 target_pid_to_str (lp->ptid),
1375 gdb_signal_to_string (signo));
1379 *status = W_STOPCODE (gdb_signal_to_host (signo));
1381 if (debug_linux_nat)
1382 fprintf_unfiltered (gdb_stdlog,
1383 "GPT: lwp %s has pending signal %s\n",
1384 target_pid_to_str (lp->ptid),
1385 gdb_signal_to_string (signo));
1392 detach_callback (struct lwp_info *lp, void *data)
1394 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1396 if (debug_linux_nat && lp->status)
1397 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1398 strsignal (WSTOPSIG (lp->status)),
1399 target_pid_to_str (lp->ptid));
1401 /* If there is a pending SIGSTOP, get rid of it. */
1404 if (debug_linux_nat)
1405 fprintf_unfiltered (gdb_stdlog,
1406 "DC: Sending SIGCONT to %s\n",
1407 target_pid_to_str (lp->ptid));
1409 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1413 /* We don't actually detach from the LWP that has an id equal to the
1414 overall process id just yet. */
1415 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1419 /* Pass on any pending signal for this LWP. */
1420 get_pending_status (lp, &status);
1422 if (linux_nat_prepare_to_resume != NULL)
1423 linux_nat_prepare_to_resume (lp);
1425 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1426 WSTOPSIG (status)) < 0)
1427 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1428 safe_strerror (errno));
1430 if (debug_linux_nat)
1431 fprintf_unfiltered (gdb_stdlog,
1432 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1433 target_pid_to_str (lp->ptid),
1434 strsignal (WSTOPSIG (status)));
1436 delete_lwp (lp->ptid);
1443 linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
1447 struct lwp_info *main_lwp;
1449 pid = ptid_get_pid (inferior_ptid);
1451 /* Don't unregister from the event loop, as there may be other
1452 inferiors running. */
1454 /* Stop all threads before detaching. ptrace requires that the
1455 thread is stopped to sucessfully detach. */
1456 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1457 /* ... and wait until all of them have reported back that
1458 they're no longer running. */
1459 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1461 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1463 /* Only the initial process should be left right now. */
1464 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1466 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1468 /* Pass on any pending signal for the last LWP. */
1469 if ((args == NULL || *args == '\0')
1470 && get_pending_status (main_lwp, &status) != -1
1471 && WIFSTOPPED (status))
1475 /* Put the signal number in ARGS so that inf_ptrace_detach will
1476 pass it along with PTRACE_DETACH. */
1478 xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
1480 if (debug_linux_nat)
1481 fprintf_unfiltered (gdb_stdlog,
1482 "LND: Sending signal %s to %s\n",
1484 target_pid_to_str (main_lwp->ptid));
1487 if (linux_nat_prepare_to_resume != NULL)
1488 linux_nat_prepare_to_resume (main_lwp);
1489 delete_lwp (main_lwp->ptid);
1491 if (forks_exist_p ())
1493 /* Multi-fork case. The current inferior_ptid is being detached
1494 from, but there are other viable forks to debug. Detach from
1495 the current fork, and context-switch to the first
1497 linux_fork_detach (args, from_tty);
1500 linux_ops->to_detach (ops, args, from_tty);
1503 /* Resume execution of the inferior process. If STEP is nonzero,
1504 single-step it. If SIGNAL is nonzero, give it that signal. */
1507 linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1511 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1512 We only presently need that if the LWP is stepped though (to
1513 handle the case of stepping a breakpoint instruction). */
1516 struct regcache *regcache = get_thread_regcache (lp->ptid);
1518 lp->stop_pc = regcache_read_pc (regcache);
1523 if (linux_nat_prepare_to_resume != NULL)
1524 linux_nat_prepare_to_resume (lp);
1525 linux_ops->to_resume (linux_ops, lp->ptid, step, signo);
1526 lp->stop_reason = LWP_STOPPED_BY_NO_REASON;
1528 registers_changed_ptid (lp->ptid);
1534 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1538 struct inferior *inf = find_inferior_ptid (lp->ptid);
1540 if (inf->vfork_child != NULL)
1542 if (debug_linux_nat)
1543 fprintf_unfiltered (gdb_stdlog,
1544 "RC: Not resuming %s (vfork parent)\n",
1545 target_pid_to_str (lp->ptid));
1547 else if (!lwp_status_pending_p (lp))
1549 if (debug_linux_nat)
1550 fprintf_unfiltered (gdb_stdlog,
1551 "RC: Resuming sibling %s, %s, %s\n",
1552 target_pid_to_str (lp->ptid),
1553 (signo != GDB_SIGNAL_0
1554 ? strsignal (gdb_signal_to_host (signo))
1556 step ? "step" : "resume");
1558 linux_resume_one_lwp (lp, step, signo);
1562 if (debug_linux_nat)
1563 fprintf_unfiltered (gdb_stdlog,
1564 "RC: Not resuming sibling %s (has pending)\n",
1565 target_pid_to_str (lp->ptid));
1570 if (debug_linux_nat)
1571 fprintf_unfiltered (gdb_stdlog,
1572 "RC: Not resuming sibling %s (not stopped)\n",
1573 target_pid_to_str (lp->ptid));
1577 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1578 Resume LWP with the last stop signal, if it is in pass state. */
1581 linux_nat_resume_callback (struct lwp_info *lp, void *except)
1583 enum gdb_signal signo = GDB_SIGNAL_0;
1590 struct thread_info *thread;
1592 thread = find_thread_ptid (lp->ptid);
1595 signo = thread->suspend.stop_signal;
1596 thread->suspend.stop_signal = GDB_SIGNAL_0;
1600 resume_lwp (lp, 0, signo);
1605 resume_clear_callback (struct lwp_info *lp, void *data)
1608 lp->last_resume_kind = resume_stop;
1613 resume_set_callback (struct lwp_info *lp, void *data)
1616 lp->last_resume_kind = resume_continue;
1621 linux_nat_resume (struct target_ops *ops,
1622 ptid_t ptid, int step, enum gdb_signal signo)
1624 struct lwp_info *lp;
1627 if (debug_linux_nat)
1628 fprintf_unfiltered (gdb_stdlog,
1629 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1630 step ? "step" : "resume",
1631 target_pid_to_str (ptid),
1632 (signo != GDB_SIGNAL_0
1633 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1634 target_pid_to_str (inferior_ptid));
1636 /* A specific PTID means `step only this process id'. */
1637 resume_many = (ptid_equal (minus_one_ptid, ptid)
1638 || ptid_is_pid (ptid));
1640 /* Mark the lwps we're resuming as resumed. */
1641 iterate_over_lwps (ptid, resume_set_callback, NULL);
1643 /* See if it's the current inferior that should be handled
1646 lp = find_lwp_pid (inferior_ptid);
1648 lp = find_lwp_pid (ptid);
1649 gdb_assert (lp != NULL);
1651 /* Remember if we're stepping. */
1652 lp->last_resume_kind = step ? resume_step : resume_continue;
1654 /* If we have a pending wait status for this thread, there is no
1655 point in resuming the process. But first make sure that
1656 linux_nat_wait won't preemptively handle the event - we
1657 should never take this short-circuit if we are going to
1658 leave LP running, since we have skipped resuming all the
1659 other threads. This bit of code needs to be synchronized
1660 with linux_nat_wait. */
1662 if (lp->status && WIFSTOPPED (lp->status))
1665 && WSTOPSIG (lp->status)
1666 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1668 if (debug_linux_nat)
1669 fprintf_unfiltered (gdb_stdlog,
1670 "LLR: Not short circuiting for ignored "
1671 "status 0x%x\n", lp->status);
1673 /* FIXME: What should we do if we are supposed to continue
1674 this thread with a signal? */
1675 gdb_assert (signo == GDB_SIGNAL_0);
1676 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1681 if (lwp_status_pending_p (lp))
1683 /* FIXME: What should we do if we are supposed to continue
1684 this thread with a signal? */
1685 gdb_assert (signo == GDB_SIGNAL_0);
1687 if (debug_linux_nat)
1688 fprintf_unfiltered (gdb_stdlog,
1689 "LLR: Short circuiting for status 0x%x\n",
1692 if (target_can_async_p ())
1694 target_async (inferior_event_handler, 0);
1695 /* Tell the event loop we have something to process. */
1702 iterate_over_lwps (ptid, linux_nat_resume_callback, lp);
1704 linux_resume_one_lwp (lp, step, signo);
1706 if (debug_linux_nat)
1707 fprintf_unfiltered (gdb_stdlog,
1708 "LLR: %s %s, %s (resume event thread)\n",
1709 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1710 target_pid_to_str (ptid),
1711 (signo != GDB_SIGNAL_0
1712 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1714 if (target_can_async_p ())
1715 target_async (inferior_event_handler, 0);
1718 /* Send a signal to an LWP. */
1721 kill_lwp (int lwpid, int signo)
1723 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1724 fails, then we are not using nptl threads and we should be using kill. */
1726 #ifdef HAVE_TKILL_SYSCALL
1728 static int tkill_failed;
1735 ret = syscall (__NR_tkill, lwpid, signo);
1736 if (errno != ENOSYS)
1743 return kill (lwpid, signo);
1746 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1747 event, check if the core is interested in it: if not, ignore the
1748 event, and keep waiting; otherwise, we need to toggle the LWP's
1749 syscall entry/exit status, since the ptrace event itself doesn't
1750 indicate it, and report the trap to higher layers. */
1753 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1755 struct target_waitstatus *ourstatus = &lp->waitstatus;
1756 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1757 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1761 /* If we're stopping threads, there's a SIGSTOP pending, which
1762 makes it so that the LWP reports an immediate syscall return,
1763 followed by the SIGSTOP. Skip seeing that "return" using
1764 PTRACE_CONT directly, and let stop_wait_callback collect the
1765 SIGSTOP. Later when the thread is resumed, a new syscall
1766 entry event. If we didn't do this (and returned 0), we'd
1767 leave a syscall entry pending, and our caller, by using
1768 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1769 itself. Later, when the user re-resumes this LWP, we'd see
1770 another syscall entry event and we'd mistake it for a return.
1772 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1773 (leaving immediately with LWP->signalled set, without issuing
1774 a PTRACE_CONT), it would still be problematic to leave this
1775 syscall enter pending, as later when the thread is resumed,
1776 it would then see the same syscall exit mentioned above,
1777 followed by the delayed SIGSTOP, while the syscall didn't
1778 actually get to execute. It seems it would be even more
1779 confusing to the user. */
1781 if (debug_linux_nat)
1782 fprintf_unfiltered (gdb_stdlog,
1783 "LHST: ignoring syscall %d "
1784 "for LWP %ld (stopping threads), "
1785 "resuming with PTRACE_CONT for SIGSTOP\n",
1787 ptid_get_lwp (lp->ptid));
1789 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1790 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1795 if (catch_syscall_enabled ())
1797 /* Always update the entry/return state, even if this particular
1798 syscall isn't interesting to the core now. In async mode,
1799 the user could install a new catchpoint for this syscall
1800 between syscall enter/return, and we'll need to know to
1801 report a syscall return if that happens. */
1802 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1803 ? TARGET_WAITKIND_SYSCALL_RETURN
1804 : TARGET_WAITKIND_SYSCALL_ENTRY);
1806 if (catching_syscall_number (syscall_number))
1808 /* Alright, an event to report. */
1809 ourstatus->kind = lp->syscall_state;
1810 ourstatus->value.syscall_number = syscall_number;
1812 if (debug_linux_nat)
1813 fprintf_unfiltered (gdb_stdlog,
1814 "LHST: stopping for %s of syscall %d"
1817 == TARGET_WAITKIND_SYSCALL_ENTRY
1818 ? "entry" : "return",
1820 ptid_get_lwp (lp->ptid));
1824 if (debug_linux_nat)
1825 fprintf_unfiltered (gdb_stdlog,
1826 "LHST: ignoring %s of syscall %d "
1828 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1829 ? "entry" : "return",
1831 ptid_get_lwp (lp->ptid));
1835 /* If we had been syscall tracing, and hence used PT_SYSCALL
1836 before on this LWP, it could happen that the user removes all
1837 syscall catchpoints before we get to process this event.
1838 There are two noteworthy issues here:
1840 - When stopped at a syscall entry event, resuming with
1841 PT_STEP still resumes executing the syscall and reports a
1844 - Only PT_SYSCALL catches syscall enters. If we last
1845 single-stepped this thread, then this event can't be a
1846 syscall enter. If we last single-stepped this thread, this
1847 has to be a syscall exit.
1849 The points above mean that the next resume, be it PT_STEP or
1850 PT_CONTINUE, can not trigger a syscall trace event. */
1851 if (debug_linux_nat)
1852 fprintf_unfiltered (gdb_stdlog,
1853 "LHST: caught syscall event "
1854 "with no syscall catchpoints."
1855 " %d for LWP %ld, ignoring\n",
1857 ptid_get_lwp (lp->ptid));
1858 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1861 /* The core isn't interested in this event. For efficiency, avoid
1862 stopping all threads only to have the core resume them all again.
1863 Since we're not stopping threads, if we're still syscall tracing
1864 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1865 subsequent syscall. Simply resume using the inf-ptrace layer,
1866 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1868 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
1872 /* Handle a GNU/Linux extended wait response. If we see a clone
1873 event, we need to add the new LWP to our list (and not report the
1874 trap to higher layers). This function returns non-zero if the
1875 event should be ignored and we should wait again. If STOPPING is
1876 true, the new LWP remains stopped, otherwise it is continued. */
1879 linux_handle_extended_wait (struct lwp_info *lp, int status,
1882 int pid = ptid_get_lwp (lp->ptid);
1883 struct target_waitstatus *ourstatus = &lp->waitstatus;
1884 int event = linux_ptrace_get_extended_event (status);
1886 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1887 || event == PTRACE_EVENT_CLONE)
1889 unsigned long new_pid;
1892 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
1894 /* If we haven't already seen the new PID stop, wait for it now. */
1895 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
1897 /* The new child has a pending SIGSTOP. We can't affect it until it
1898 hits the SIGSTOP, but we're already attached. */
1899 ret = my_waitpid (new_pid, &status,
1900 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
1902 perror_with_name (_("waiting for new child"));
1903 else if (ret != new_pid)
1904 internal_error (__FILE__, __LINE__,
1905 _("wait returned unexpected PID %d"), ret);
1906 else if (!WIFSTOPPED (status))
1907 internal_error (__FILE__, __LINE__,
1908 _("wait returned unexpected status 0x%x"), status);
1911 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
1913 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
1915 /* The arch-specific native code may need to know about new
1916 forks even if those end up never mapped to an
1918 if (linux_nat_new_fork != NULL)
1919 linux_nat_new_fork (lp, new_pid);
1922 if (event == PTRACE_EVENT_FORK
1923 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
1925 /* Handle checkpointing by linux-fork.c here as a special
1926 case. We don't want the follow-fork-mode or 'catch fork'
1927 to interfere with this. */
1929 /* This won't actually modify the breakpoint list, but will
1930 physically remove the breakpoints from the child. */
1931 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
1933 /* Retain child fork in ptrace (stopped) state. */
1934 if (!find_fork_pid (new_pid))
1937 /* Report as spurious, so that infrun doesn't want to follow
1938 this fork. We're actually doing an infcall in
1940 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
1942 /* Report the stop to the core. */
1946 if (event == PTRACE_EVENT_FORK)
1947 ourstatus->kind = TARGET_WAITKIND_FORKED;
1948 else if (event == PTRACE_EVENT_VFORK)
1949 ourstatus->kind = TARGET_WAITKIND_VFORKED;
1952 struct lwp_info *new_lp;
1954 ourstatus->kind = TARGET_WAITKIND_IGNORE;
1956 if (debug_linux_nat)
1957 fprintf_unfiltered (gdb_stdlog,
1958 "LHEW: Got clone event "
1959 "from LWP %d, new child is LWP %ld\n",
1962 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
1964 new_lp->stopped = 1;
1966 if (WSTOPSIG (status) != SIGSTOP)
1968 /* This can happen if someone starts sending signals to
1969 the new thread before it gets a chance to run, which
1970 have a lower number than SIGSTOP (e.g. SIGUSR1).
1971 This is an unlikely case, and harder to handle for
1972 fork / vfork than for clone, so we do not try - but
1973 we handle it for clone events here. We'll send
1974 the other signal on to the thread below. */
1976 new_lp->signalled = 1;
1980 struct thread_info *tp;
1982 /* When we stop for an event in some other thread, and
1983 pull the thread list just as this thread has cloned,
1984 we'll have seen the new thread in the thread_db list
1985 before handling the CLONE event (glibc's
1986 pthread_create adds the new thread to the thread list
1987 before clone'ing, and has the kernel fill in the
1988 thread's tid on the clone call with
1989 CLONE_PARENT_SETTID). If that happened, and the core
1990 had requested the new thread to stop, we'll have
1991 killed it with SIGSTOP. But since SIGSTOP is not an
1992 RT signal, it can only be queued once. We need to be
1993 careful to not resume the LWP if we wanted it to
1994 stop. In that case, we'll leave the SIGSTOP pending.
1995 It will later be reported as GDB_SIGNAL_0. */
1996 tp = find_thread_ptid (new_lp->ptid);
1997 if (tp != NULL && tp->stop_requested)
1998 new_lp->last_resume_kind = resume_stop;
2003 /* If the thread_db layer is active, let it record the user
2004 level thread id and status, and add the thread to GDB's
2006 if (!thread_db_notice_clone (lp->ptid, new_lp->ptid))
2008 /* The process is not using thread_db. Add the LWP to
2010 target_post_attach (ptid_get_lwp (new_lp->ptid));
2011 add_thread (new_lp->ptid);
2016 set_running (new_lp->ptid, 1);
2017 set_executing (new_lp->ptid, 1);
2018 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2020 new_lp->last_resume_kind = resume_continue;
2025 /* We created NEW_LP so it cannot yet contain STATUS. */
2026 gdb_assert (new_lp->status == 0);
2028 /* Save the wait status to report later. */
2029 if (debug_linux_nat)
2030 fprintf_unfiltered (gdb_stdlog,
2031 "LHEW: waitpid of new LWP %ld, "
2032 "saving status %s\n",
2033 (long) ptid_get_lwp (new_lp->ptid),
2034 status_to_str (status));
2035 new_lp->status = status;
2038 new_lp->resumed = !stopping;
2045 if (event == PTRACE_EVENT_EXEC)
2047 if (debug_linux_nat)
2048 fprintf_unfiltered (gdb_stdlog,
2049 "LHEW: Got exec event from LWP %ld\n",
2050 ptid_get_lwp (lp->ptid));
2052 ourstatus->kind = TARGET_WAITKIND_EXECD;
2053 ourstatus->value.execd_pathname
2054 = xstrdup (linux_child_pid_to_exec_file (NULL, pid));
2056 /* The thread that execed must have been resumed, but, when a
2057 thread execs, it changes its tid to the tgid, and the old
2058 tgid thread might have not been resumed. */
2063 if (event == PTRACE_EVENT_VFORK_DONE)
2065 if (current_inferior ()->waiting_for_vfork_done)
2067 if (debug_linux_nat)
2068 fprintf_unfiltered (gdb_stdlog,
2069 "LHEW: Got expected PTRACE_EVENT_"
2070 "VFORK_DONE from LWP %ld: stopping\n",
2071 ptid_get_lwp (lp->ptid));
2073 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2077 if (debug_linux_nat)
2078 fprintf_unfiltered (gdb_stdlog,
2079 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2080 "from LWP %ld: ignoring\n",
2081 ptid_get_lwp (lp->ptid));
2085 internal_error (__FILE__, __LINE__,
2086 _("unknown ptrace event %d"), event);
2089 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2093 wait_lwp (struct lwp_info *lp)
2097 int thread_dead = 0;
2100 gdb_assert (!lp->stopped);
2101 gdb_assert (lp->status == 0);
2103 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2104 block_child_signals (&prev_mask);
2108 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2109 was right and we should just call sigsuspend. */
2111 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2112 if (pid == -1 && errno == ECHILD)
2113 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2114 if (pid == -1 && errno == ECHILD)
2116 /* The thread has previously exited. We need to delete it
2117 now because, for some vendor 2.4 kernels with NPTL
2118 support backported, there won't be an exit event unless
2119 it is the main thread. 2.6 kernels will report an exit
2120 event for each thread that exits, as expected. */
2122 if (debug_linux_nat)
2123 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2124 target_pid_to_str (lp->ptid));
2129 /* Bugs 10970, 12702.
2130 Thread group leader may have exited in which case we'll lock up in
2131 waitpid if there are other threads, even if they are all zombies too.
2132 Basically, we're not supposed to use waitpid this way.
2133 __WCLONE is not applicable for the leader so we can't use that.
2134 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2135 process; it gets ESRCH both for the zombie and for running processes.
2137 As a workaround, check if we're waiting for the thread group leader and
2138 if it's a zombie, and avoid calling waitpid if it is.
2140 This is racy, what if the tgl becomes a zombie right after we check?
2141 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2142 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2144 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2145 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2148 if (debug_linux_nat)
2149 fprintf_unfiltered (gdb_stdlog,
2150 "WL: Thread group leader %s vanished.\n",
2151 target_pid_to_str (lp->ptid));
2155 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2156 get invoked despite our caller had them intentionally blocked by
2157 block_child_signals. This is sensitive only to the loop of
2158 linux_nat_wait_1 and there if we get called my_waitpid gets called
2159 again before it gets to sigsuspend so we can safely let the handlers
2160 get executed here. */
2162 if (debug_linux_nat)
2163 fprintf_unfiltered (gdb_stdlog, "WL: about to sigsuspend\n");
2164 sigsuspend (&suspend_mask);
2167 restore_child_signals_mask (&prev_mask);
2171 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2173 if (debug_linux_nat)
2175 fprintf_unfiltered (gdb_stdlog,
2176 "WL: waitpid %s received %s\n",
2177 target_pid_to_str (lp->ptid),
2178 status_to_str (status));
2181 /* Check if the thread has exited. */
2182 if (WIFEXITED (status) || WIFSIGNALED (status))
2185 if (debug_linux_nat)
2186 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2187 target_pid_to_str (lp->ptid));
2197 gdb_assert (WIFSTOPPED (status));
2200 if (lp->must_set_ptrace_flags)
2202 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2204 linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
2205 lp->must_set_ptrace_flags = 0;
2208 /* Handle GNU/Linux's syscall SIGTRAPs. */
2209 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2211 /* No longer need the sysgood bit. The ptrace event ends up
2212 recorded in lp->waitstatus if we care for it. We can carry
2213 on handling the event like a regular SIGTRAP from here
2215 status = W_STOPCODE (SIGTRAP);
2216 if (linux_handle_syscall_trap (lp, 1))
2217 return wait_lwp (lp);
2220 /* Handle GNU/Linux's extended waitstatus for trace events. */
2221 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
2222 && linux_is_extended_waitstatus (status))
2224 if (debug_linux_nat)
2225 fprintf_unfiltered (gdb_stdlog,
2226 "WL: Handling extended status 0x%06x\n",
2228 linux_handle_extended_wait (lp, status, 1);
2235 /* Send a SIGSTOP to LP. */
2238 stop_callback (struct lwp_info *lp, void *data)
2240 if (!lp->stopped && !lp->signalled)
2244 if (debug_linux_nat)
2246 fprintf_unfiltered (gdb_stdlog,
2247 "SC: kill %s **<SIGSTOP>**\n",
2248 target_pid_to_str (lp->ptid));
2251 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2252 if (debug_linux_nat)
2254 fprintf_unfiltered (gdb_stdlog,
2255 "SC: lwp kill %d %s\n",
2257 errno ? safe_strerror (errno) : "ERRNO-OK");
2261 gdb_assert (lp->status == 0);
2267 /* Request a stop on LWP. */
2270 linux_stop_lwp (struct lwp_info *lwp)
2272 stop_callback (lwp, NULL);
2275 /* See linux-nat.h */
2278 linux_stop_and_wait_all_lwps (void)
2280 /* Stop all LWP's ... */
2281 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
2283 /* ... and wait until all of them have reported back that
2284 they're no longer running. */
2285 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
2288 /* See linux-nat.h */
2291 linux_unstop_all_lwps (void)
2293 iterate_over_lwps (minus_one_ptid,
2294 resume_stopped_resumed_lwps, &minus_one_ptid);
2297 /* Return non-zero if LWP PID has a pending SIGINT. */
2300 linux_nat_has_pending_sigint (int pid)
2302 sigset_t pending, blocked, ignored;
2304 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2306 if (sigismember (&pending, SIGINT)
2307 && !sigismember (&ignored, SIGINT))
2313 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2316 set_ignore_sigint (struct lwp_info *lp, void *data)
2318 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2319 flag to consume the next one. */
2320 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2321 && WSTOPSIG (lp->status) == SIGINT)
2324 lp->ignore_sigint = 1;
2329 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2330 This function is called after we know the LWP has stopped; if the LWP
2331 stopped before the expected SIGINT was delivered, then it will never have
2332 arrived. Also, if the signal was delivered to a shared queue and consumed
2333 by a different thread, it will never be delivered to this LWP. */
2336 maybe_clear_ignore_sigint (struct lwp_info *lp)
2338 if (!lp->ignore_sigint)
2341 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2343 if (debug_linux_nat)
2344 fprintf_unfiltered (gdb_stdlog,
2345 "MCIS: Clearing bogus flag for %s\n",
2346 target_pid_to_str (lp->ptid));
2347 lp->ignore_sigint = 0;
2351 /* Fetch the possible triggered data watchpoint info and store it in
2354 On some archs, like x86, that use debug registers to set
2355 watchpoints, it's possible that the way to know which watched
2356 address trapped, is to check the register that is used to select
2357 which address to watch. Problem is, between setting the watchpoint
2358 and reading back which data address trapped, the user may change
2359 the set of watchpoints, and, as a consequence, GDB changes the
2360 debug registers in the inferior. To avoid reading back a stale
2361 stopped-data-address when that happens, we cache in LP the fact
2362 that a watchpoint trapped, and the corresponding data address, as
2363 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2364 registers meanwhile, we have the cached data we can rely on. */
2367 check_stopped_by_watchpoint (struct lwp_info *lp)
2369 struct cleanup *old_chain;
2371 if (linux_ops->to_stopped_by_watchpoint == NULL)
2374 old_chain = save_inferior_ptid ();
2375 inferior_ptid = lp->ptid;
2377 if (linux_ops->to_stopped_by_watchpoint (linux_ops))
2379 lp->stop_reason = LWP_STOPPED_BY_WATCHPOINT;
2381 if (linux_ops->to_stopped_data_address != NULL)
2382 lp->stopped_data_address_p =
2383 linux_ops->to_stopped_data_address (¤t_target,
2384 &lp->stopped_data_address);
2386 lp->stopped_data_address_p = 0;
2389 do_cleanups (old_chain);
2391 return lp->stop_reason == LWP_STOPPED_BY_WATCHPOINT;
2394 /* Called when the LWP stopped for a trap that could be explained by a
2395 watchpoint or a breakpoint. */
2398 save_sigtrap (struct lwp_info *lp)
2400 gdb_assert (lp->stop_reason == LWP_STOPPED_BY_NO_REASON);
2401 gdb_assert (lp->status != 0);
2403 if (check_stopped_by_watchpoint (lp))
2406 if (linux_nat_status_is_event (lp->status))
2407 check_stopped_by_breakpoint (lp);
2410 /* Returns true if the LWP had stopped for a watchpoint. */
2413 linux_nat_stopped_by_watchpoint (struct target_ops *ops)
2415 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2417 gdb_assert (lp != NULL);
2419 return lp->stop_reason == LWP_STOPPED_BY_WATCHPOINT;
2423 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2425 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2427 gdb_assert (lp != NULL);
2429 *addr_p = lp->stopped_data_address;
2431 return lp->stopped_data_address_p;
2434 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2437 sigtrap_is_event (int status)
2439 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2442 /* Set alternative SIGTRAP-like events recognizer. If
2443 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2447 linux_nat_set_status_is_event (struct target_ops *t,
2448 int (*status_is_event) (int status))
2450 linux_nat_status_is_event = status_is_event;
2453 /* Wait until LP is stopped. */
2456 stop_wait_callback (struct lwp_info *lp, void *data)
2458 struct inferior *inf = find_inferior_ptid (lp->ptid);
2460 /* If this is a vfork parent, bail out, it is not going to report
2461 any SIGSTOP until the vfork is done with. */
2462 if (inf->vfork_child != NULL)
2469 status = wait_lwp (lp);
2473 if (lp->ignore_sigint && WIFSTOPPED (status)
2474 && WSTOPSIG (status) == SIGINT)
2476 lp->ignore_sigint = 0;
2479 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2481 if (debug_linux_nat)
2482 fprintf_unfiltered (gdb_stdlog,
2483 "PTRACE_CONT %s, 0, 0 (%s) "
2484 "(discarding SIGINT)\n",
2485 target_pid_to_str (lp->ptid),
2486 errno ? safe_strerror (errno) : "OK");
2488 return stop_wait_callback (lp, NULL);
2491 maybe_clear_ignore_sigint (lp);
2493 if (WSTOPSIG (status) != SIGSTOP)
2495 /* The thread was stopped with a signal other than SIGSTOP. */
2497 if (debug_linux_nat)
2498 fprintf_unfiltered (gdb_stdlog,
2499 "SWC: Pending event %s in %s\n",
2500 status_to_str ((int) status),
2501 target_pid_to_str (lp->ptid));
2503 /* Save the sigtrap event. */
2504 lp->status = status;
2505 gdb_assert (lp->signalled);
2510 /* We caught the SIGSTOP that we intended to catch, so
2511 there's no SIGSTOP pending. */
2513 if (debug_linux_nat)
2514 fprintf_unfiltered (gdb_stdlog,
2515 "SWC: Delayed SIGSTOP caught for %s.\n",
2516 target_pid_to_str (lp->ptid));
2518 /* Reset SIGNALLED only after the stop_wait_callback call
2519 above as it does gdb_assert on SIGNALLED. */
2527 /* Return non-zero if LP has a wait status pending. Discard the
2528 pending event and resume the LWP if the event that originally
2529 caused the stop became uninteresting. */
2532 status_callback (struct lwp_info *lp, void *data)
2534 /* Only report a pending wait status if we pretend that this has
2535 indeed been resumed. */
2539 if (lp->stop_reason == LWP_STOPPED_BY_SW_BREAKPOINT
2540 || lp->stop_reason == LWP_STOPPED_BY_HW_BREAKPOINT)
2542 struct regcache *regcache = get_thread_regcache (lp->ptid);
2543 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2547 gdb_assert (lp->status != 0);
2549 pc = regcache_read_pc (regcache);
2551 if (pc != lp->stop_pc)
2553 if (debug_linux_nat)
2554 fprintf_unfiltered (gdb_stdlog,
2555 "SC: PC of %s changed. was=%s, now=%s\n",
2556 target_pid_to_str (lp->ptid),
2557 paddress (target_gdbarch (), lp->stop_pc),
2558 paddress (target_gdbarch (), pc));
2561 else if (!breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2563 if (debug_linux_nat)
2564 fprintf_unfiltered (gdb_stdlog,
2565 "SC: previous breakpoint of %s, at %s gone\n",
2566 target_pid_to_str (lp->ptid),
2567 paddress (target_gdbarch (), lp->stop_pc));
2574 if (debug_linux_nat)
2575 fprintf_unfiltered (gdb_stdlog,
2576 "SC: pending event of %s cancelled.\n",
2577 target_pid_to_str (lp->ptid));
2580 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
2586 return lwp_status_pending_p (lp);
2589 /* Return non-zero if LP isn't stopped. */
2592 running_callback (struct lwp_info *lp, void *data)
2594 return (!lp->stopped
2595 || (lwp_status_pending_p (lp) && lp->resumed));
2598 /* Count the LWP's that have had events. */
2601 count_events_callback (struct lwp_info *lp, void *data)
2605 gdb_assert (count != NULL);
2607 /* Select only resumed LWPs that have an event pending. */
2608 if (lp->resumed && lwp_status_pending_p (lp))
2614 /* Select the LWP (if any) that is currently being single-stepped. */
2617 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2619 if (lp->last_resume_kind == resume_step
2626 /* Returns true if LP has a status pending. */
2629 lwp_status_pending_p (struct lwp_info *lp)
2631 /* We check for lp->waitstatus in addition to lp->status, because we
2632 can have pending process exits recorded in lp->status and
2633 W_EXITCODE(0,0) happens to be 0. */
2634 return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE;
2637 /* Select the Nth LWP that has had a SIGTRAP event. */
2640 select_event_lwp_callback (struct lwp_info *lp, void *data)
2642 int *selector = data;
2644 gdb_assert (selector != NULL);
2646 /* Select only resumed LWPs that have an event pending. */
2647 if (lp->resumed && lwp_status_pending_p (lp))
2648 if ((*selector)-- == 0)
2654 /* Called when the LWP got a signal/trap that could be explained by a
2655 software or hardware breakpoint. */
2658 check_stopped_by_breakpoint (struct lwp_info *lp)
2660 /* Arrange for a breakpoint to be hit again later. We don't keep
2661 the SIGTRAP status and don't forward the SIGTRAP signal to the
2662 LWP. We will handle the current event, eventually we will resume
2663 this LWP, and this breakpoint will trap again.
2665 If we do not do this, then we run the risk that the user will
2666 delete or disable the breakpoint, but the LWP will have already
2669 struct regcache *regcache = get_thread_regcache (lp->ptid);
2670 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2674 pc = regcache_read_pc (regcache);
2675 sw_bp_pc = pc - target_decr_pc_after_break (gdbarch);
2677 if ((!lp->step || lp->stop_pc == sw_bp_pc)
2678 && software_breakpoint_inserted_here_p (get_regcache_aspace (regcache),
2681 /* The LWP was either continued, or stepped a software
2682 breakpoint instruction. */
2683 if (debug_linux_nat)
2684 fprintf_unfiltered (gdb_stdlog,
2685 "CB: Push back software breakpoint for %s\n",
2686 target_pid_to_str (lp->ptid));
2688 /* Back up the PC if necessary. */
2690 regcache_write_pc (regcache, sw_bp_pc);
2692 lp->stop_pc = sw_bp_pc;
2693 lp->stop_reason = LWP_STOPPED_BY_SW_BREAKPOINT;
2697 if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2699 if (debug_linux_nat)
2700 fprintf_unfiltered (gdb_stdlog,
2701 "CB: Push back hardware breakpoint for %s\n",
2702 target_pid_to_str (lp->ptid));
2705 lp->stop_reason = LWP_STOPPED_BY_HW_BREAKPOINT;
2712 /* Select one LWP out of those that have events pending. */
2715 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2718 int random_selector;
2719 struct lwp_info *event_lp = NULL;
2721 /* Record the wait status for the original LWP. */
2722 (*orig_lp)->status = *status;
2724 /* In all-stop, give preference to the LWP that is being
2725 single-stepped. There will be at most one, and it will be the
2726 LWP that the core is most interested in. If we didn't do this,
2727 then we'd have to handle pending step SIGTRAPs somehow in case
2728 the core later continues the previously-stepped thread, as
2729 otherwise we'd report the pending SIGTRAP then, and the core, not
2730 having stepped the thread, wouldn't understand what the trap was
2731 for, and therefore would report it to the user as a random
2735 event_lp = iterate_over_lwps (filter,
2736 select_singlestep_lwp_callback, NULL);
2737 if (event_lp != NULL)
2739 if (debug_linux_nat)
2740 fprintf_unfiltered (gdb_stdlog,
2741 "SEL: Select single-step %s\n",
2742 target_pid_to_str (event_lp->ptid));
2746 if (event_lp == NULL)
2748 /* Pick one at random, out of those which have had events. */
2750 /* First see how many events we have. */
2751 iterate_over_lwps (filter, count_events_callback, &num_events);
2753 /* Now randomly pick a LWP out of those that have had
2755 random_selector = (int)
2756 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2758 if (debug_linux_nat && num_events > 1)
2759 fprintf_unfiltered (gdb_stdlog,
2760 "SEL: Found %d events, selecting #%d\n",
2761 num_events, random_selector);
2763 event_lp = iterate_over_lwps (filter,
2764 select_event_lwp_callback,
2768 if (event_lp != NULL)
2770 /* Switch the event LWP. */
2771 *orig_lp = event_lp;
2772 *status = event_lp->status;
2775 /* Flush the wait status for the event LWP. */
2776 (*orig_lp)->status = 0;
2779 /* Return non-zero if LP has been resumed. */
2782 resumed_callback (struct lwp_info *lp, void *data)
2787 /* Stop an active thread, verify it still exists, then resume it. If
2788 the thread ends up with a pending status, then it is not resumed,
2789 and *DATA (really a pointer to int), is set. */
2792 stop_and_resume_callback (struct lwp_info *lp, void *data)
2796 ptid_t ptid = lp->ptid;
2798 stop_callback (lp, NULL);
2799 stop_wait_callback (lp, NULL);
2801 /* Resume if the lwp still exists, and the core wanted it
2803 lp = find_lwp_pid (ptid);
2806 if (lp->last_resume_kind == resume_stop
2807 && !lwp_status_pending_p (lp))
2809 /* The core wanted the LWP to stop. Even if it stopped
2810 cleanly (with SIGSTOP), leave the event pending. */
2811 if (debug_linux_nat)
2812 fprintf_unfiltered (gdb_stdlog,
2813 "SARC: core wanted LWP %ld stopped "
2814 "(leaving SIGSTOP pending)\n",
2815 ptid_get_lwp (lp->ptid));
2816 lp->status = W_STOPCODE (SIGSTOP);
2819 if (!lwp_status_pending_p (lp))
2821 if (debug_linux_nat)
2822 fprintf_unfiltered (gdb_stdlog,
2823 "SARC: re-resuming LWP %ld\n",
2824 ptid_get_lwp (lp->ptid));
2825 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2829 if (debug_linux_nat)
2830 fprintf_unfiltered (gdb_stdlog,
2831 "SARC: not re-resuming LWP %ld "
2833 ptid_get_lwp (lp->ptid));
2840 /* Check if we should go on and pass this event to common code.
2841 Return the affected lwp if we are, or NULL otherwise. */
2843 static struct lwp_info *
2844 linux_nat_filter_event (int lwpid, int status)
2846 struct lwp_info *lp;
2847 int event = linux_ptrace_get_extended_event (status);
2849 lp = find_lwp_pid (pid_to_ptid (lwpid));
2851 /* Check for stop events reported by a process we didn't already
2852 know about - anything not already in our LWP list.
2854 If we're expecting to receive stopped processes after
2855 fork, vfork, and clone events, then we'll just add the
2856 new one to our list and go back to waiting for the event
2857 to be reported - the stopped process might be returned
2858 from waitpid before or after the event is.
2860 But note the case of a non-leader thread exec'ing after the
2861 leader having exited, and gone from our lists. The non-leader
2862 thread changes its tid to the tgid. */
2864 if (WIFSTOPPED (status) && lp == NULL
2865 && (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
2867 /* A multi-thread exec after we had seen the leader exiting. */
2868 if (debug_linux_nat)
2869 fprintf_unfiltered (gdb_stdlog,
2870 "LLW: Re-adding thread group leader LWP %d.\n",
2873 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2876 add_thread (lp->ptid);
2879 if (WIFSTOPPED (status) && !lp)
2881 if (debug_linux_nat)
2882 fprintf_unfiltered (gdb_stdlog,
2883 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2884 (long) lwpid, status_to_str (status));
2885 add_to_pid_list (&stopped_pids, lwpid, status);
2889 /* Make sure we don't report an event for the exit of an LWP not in
2890 our list, i.e. not part of the current process. This can happen
2891 if we detach from a program we originally forked and then it
2893 if (!WIFSTOPPED (status) && !lp)
2896 /* This LWP is stopped now. (And if dead, this prevents it from
2897 ever being continued.) */
2900 if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
2902 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2904 linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
2905 lp->must_set_ptrace_flags = 0;
2908 /* Handle GNU/Linux's syscall SIGTRAPs. */
2909 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2911 /* No longer need the sysgood bit. The ptrace event ends up
2912 recorded in lp->waitstatus if we care for it. We can carry
2913 on handling the event like a regular SIGTRAP from here
2915 status = W_STOPCODE (SIGTRAP);
2916 if (linux_handle_syscall_trap (lp, 0))
2920 /* Handle GNU/Linux's extended waitstatus for trace events. */
2921 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
2922 && linux_is_extended_waitstatus (status))
2924 if (debug_linux_nat)
2925 fprintf_unfiltered (gdb_stdlog,
2926 "LLW: Handling extended status 0x%06x\n",
2928 if (linux_handle_extended_wait (lp, status, 0))
2932 /* Check if the thread has exited. */
2933 if (WIFEXITED (status) || WIFSIGNALED (status))
2935 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
2937 /* If this is the main thread, we must stop all threads and
2938 verify if they are still alive. This is because in the
2939 nptl thread model on Linux 2.4, there is no signal issued
2940 for exiting LWPs other than the main thread. We only get
2941 the main thread exit signal once all child threads have
2942 already exited. If we stop all the threads and use the
2943 stop_wait_callback to check if they have exited we can
2944 determine whether this signal should be ignored or
2945 whether it means the end of the debugged application,
2946 regardless of which threading model is being used. */
2947 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
2949 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
2950 stop_and_resume_callback, NULL);
2953 if (debug_linux_nat)
2954 fprintf_unfiltered (gdb_stdlog,
2955 "LLW: %s exited.\n",
2956 target_pid_to_str (lp->ptid));
2958 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
2960 /* If there is at least one more LWP, then the exit signal
2961 was not the end of the debugged application and should be
2968 gdb_assert (lp->resumed);
2970 if (debug_linux_nat)
2971 fprintf_unfiltered (gdb_stdlog,
2972 "Process %ld exited\n",
2973 ptid_get_lwp (lp->ptid));
2975 /* This was the last lwp in the process. Since events are
2976 serialized to GDB core, we may not be able report this one
2977 right now, but GDB core and the other target layers will want
2978 to be notified about the exit code/signal, leave the status
2979 pending for the next time we're able to report it. */
2981 /* Dead LWP's aren't expected to reported a pending sigstop. */
2984 /* Store the pending event in the waitstatus, because
2985 W_EXITCODE(0,0) == 0. */
2986 store_waitstatus (&lp->waitstatus, status);
2990 /* Check if the current LWP has previously exited. In the nptl
2991 thread model, LWPs other than the main thread do not issue
2992 signals when they exit so we must check whenever the thread has
2993 stopped. A similar check is made in stop_wait_callback(). */
2994 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
2996 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
2998 if (debug_linux_nat)
2999 fprintf_unfiltered (gdb_stdlog,
3000 "LLW: %s exited.\n",
3001 target_pid_to_str (lp->ptid));
3005 /* Make sure there is at least one thread running. */
3006 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3008 /* Discard the event. */
3012 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3013 an attempt to stop an LWP. */
3015 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3017 if (debug_linux_nat)
3018 fprintf_unfiltered (gdb_stdlog,
3019 "LLW: Delayed SIGSTOP caught for %s.\n",
3020 target_pid_to_str (lp->ptid));
3024 if (lp->last_resume_kind != resume_stop)
3026 /* This is a delayed SIGSTOP. */
3028 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3029 if (debug_linux_nat)
3030 fprintf_unfiltered (gdb_stdlog,
3031 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3033 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3034 target_pid_to_str (lp->ptid));
3036 gdb_assert (lp->resumed);
3038 /* Discard the event. */
3043 /* Make sure we don't report a SIGINT that we have already displayed
3044 for another thread. */
3045 if (lp->ignore_sigint
3046 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3048 if (debug_linux_nat)
3049 fprintf_unfiltered (gdb_stdlog,
3050 "LLW: Delayed SIGINT caught for %s.\n",
3051 target_pid_to_str (lp->ptid));
3053 /* This is a delayed SIGINT. */
3054 lp->ignore_sigint = 0;
3056 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3057 if (debug_linux_nat)
3058 fprintf_unfiltered (gdb_stdlog,
3059 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3061 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3062 target_pid_to_str (lp->ptid));
3063 gdb_assert (lp->resumed);
3065 /* Discard the event. */
3069 /* Don't report signals that GDB isn't interested in, such as
3070 signals that are neither printed nor stopped upon. Stopping all
3071 threads can be a bit time-consuming so if we want decent
3072 performance with heavily multi-threaded programs, especially when
3073 they're using a high frequency timer, we'd better avoid it if we
3075 if (WIFSTOPPED (status))
3077 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3081 /* Only do the below in all-stop, as we currently use SIGSTOP
3082 to implement target_stop (see linux_nat_stop) in
3084 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3086 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3087 forwarded to the entire process group, that is, all LWPs
3088 will receive it - unless they're using CLONE_THREAD to
3089 share signals. Since we only want to report it once, we
3090 mark it as ignored for all LWPs except this one. */
3091 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3092 set_ignore_sigint, NULL);
3093 lp->ignore_sigint = 0;
3096 maybe_clear_ignore_sigint (lp);
3099 /* When using hardware single-step, we need to report every signal.
3100 Otherwise, signals in pass_mask may be short-circuited
3101 except signals that might be caused by a breakpoint. */
3103 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status))
3104 && !linux_wstatus_maybe_breakpoint (status))
3106 linux_resume_one_lwp (lp, lp->step, signo);
3107 if (debug_linux_nat)
3108 fprintf_unfiltered (gdb_stdlog,
3109 "LLW: %s %s, %s (preempt 'handle')\n",
3111 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3112 target_pid_to_str (lp->ptid),
3113 (signo != GDB_SIGNAL_0
3114 ? strsignal (gdb_signal_to_host (signo))
3120 /* An interesting event. */
3122 lp->status = status;
3127 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3128 their exits until all other threads in the group have exited. */
3131 check_zombie_leaders (void)
3133 struct inferior *inf;
3137 struct lwp_info *leader_lp;
3142 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3143 if (leader_lp != NULL
3144 /* Check if there are other threads in the group, as we may
3145 have raced with the inferior simply exiting. */
3146 && num_lwps (inf->pid) > 1
3147 && linux_proc_pid_is_zombie (inf->pid))
3149 if (debug_linux_nat)
3150 fprintf_unfiltered (gdb_stdlog,
3151 "CZL: Thread group leader %d zombie "
3152 "(it exited, or another thread execd).\n",
3155 /* A leader zombie can mean one of two things:
3157 - It exited, and there's an exit status pending
3158 available, or only the leader exited (not the whole
3159 program). In the latter case, we can't waitpid the
3160 leader's exit status until all other threads are gone.
3162 - There are 3 or more threads in the group, and a thread
3163 other than the leader exec'd. On an exec, the Linux
3164 kernel destroys all other threads (except the execing
3165 one) in the thread group, and resets the execing thread's
3166 tid to the tgid. No exit notification is sent for the
3167 execing thread -- from the ptracer's perspective, it
3168 appears as though the execing thread just vanishes.
3169 Until we reap all other threads except the leader and the
3170 execing thread, the leader will be zombie, and the
3171 execing thread will be in `D (disc sleep)'. As soon as
3172 all other threads are reaped, the execing thread changes
3173 it's tid to the tgid, and the previous (zombie) leader
3174 vanishes, giving place to the "new" leader. We could try
3175 distinguishing the exit and exec cases, by waiting once
3176 more, and seeing if something comes out, but it doesn't
3177 sound useful. The previous leader _does_ go away, and
3178 we'll re-add the new one once we see the exec event
3179 (which is just the same as what would happen if the
3180 previous leader did exit voluntarily before some other
3183 if (debug_linux_nat)
3184 fprintf_unfiltered (gdb_stdlog,
3185 "CZL: Thread group leader %d vanished.\n",
3187 exit_lwp (leader_lp);
3193 linux_nat_wait_1 (struct target_ops *ops,
3194 ptid_t ptid, struct target_waitstatus *ourstatus,
3198 enum resume_kind last_resume_kind;
3199 struct lwp_info *lp;
3202 if (debug_linux_nat)
3203 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3205 /* The first time we get here after starting a new inferior, we may
3206 not have added it to the LWP list yet - this is the earliest
3207 moment at which we know its PID. */
3208 if (ptid_is_pid (inferior_ptid))
3210 /* Upgrade the main thread's ptid. */
3211 thread_change_ptid (inferior_ptid,
3212 ptid_build (ptid_get_pid (inferior_ptid),
3213 ptid_get_pid (inferior_ptid), 0));
3215 lp = add_initial_lwp (inferior_ptid);
3219 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3220 block_child_signals (&prev_mask);
3222 /* First check if there is a LWP with a wait status pending. */
3223 lp = iterate_over_lwps (ptid, status_callback, NULL);
3226 if (debug_linux_nat)
3227 fprintf_unfiltered (gdb_stdlog,
3228 "LLW: Using pending wait status %s for %s.\n",
3229 status_to_str (lp->status),
3230 target_pid_to_str (lp->ptid));
3233 if (!target_is_async_p ())
3235 /* Causes SIGINT to be passed on to the attached process. */
3239 /* But if we don't find a pending event, we'll have to wait. Always
3240 pull all events out of the kernel. We'll randomly select an
3241 event LWP out of all that have events, to prevent starvation. */
3247 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3250 - If the thread group leader exits while other threads in the
3251 thread group still exist, waitpid(TGID, ...) hangs. That
3252 waitpid won't return an exit status until the other threads
3253 in the group are reapped.
3255 - When a non-leader thread execs, that thread just vanishes
3256 without reporting an exit (so we'd hang if we waited for it
3257 explicitly in that case). The exec event is reported to
3261 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3262 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3263 lwpid = my_waitpid (-1, &status, WNOHANG);
3265 if (debug_linux_nat)
3266 fprintf_unfiltered (gdb_stdlog,
3267 "LNW: waitpid(-1, ...) returned %d, %s\n",
3268 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3272 if (debug_linux_nat)
3274 fprintf_unfiltered (gdb_stdlog,
3275 "LLW: waitpid %ld received %s\n",
3276 (long) lwpid, status_to_str (status));
3279 linux_nat_filter_event (lwpid, status);
3280 /* Retry until nothing comes out of waitpid. A single
3281 SIGCHLD can indicate more than one child stopped. */
3285 /* Now that we've pulled all events out of the kernel, resume
3286 LWPs that don't have an interesting event to report. */
3287 iterate_over_lwps (minus_one_ptid,
3288 resume_stopped_resumed_lwps, &minus_one_ptid);
3290 /* ... and find an LWP with a status to report to the core, if
3292 lp = iterate_over_lwps (ptid, status_callback, NULL);
3296 /* Check for zombie thread group leaders. Those can't be reaped
3297 until all other threads in the thread group are. */
3298 check_zombie_leaders ();
3300 /* If there are no resumed children left, bail. We'd be stuck
3301 forever in the sigsuspend call below otherwise. */
3302 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3304 if (debug_linux_nat)
3305 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3307 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3309 if (!target_is_async_p ())
3310 clear_sigint_trap ();
3312 restore_child_signals_mask (&prev_mask);
3313 return minus_one_ptid;
3316 /* No interesting event to report to the core. */
3318 if (target_options & TARGET_WNOHANG)
3320 if (debug_linux_nat)
3321 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3323 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3324 restore_child_signals_mask (&prev_mask);
3325 return minus_one_ptid;
3328 /* We shouldn't end up here unless we want to try again. */
3329 gdb_assert (lp == NULL);
3331 /* Block until we get an event reported with SIGCHLD. */
3332 if (debug_linux_nat)
3333 fprintf_unfiltered (gdb_stdlog, "LNW: about to sigsuspend\n");
3334 sigsuspend (&suspend_mask);
3337 if (!target_is_async_p ())
3338 clear_sigint_trap ();
3342 status = lp->status;
3347 /* Now stop all other LWP's ... */
3348 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3350 /* ... and wait until all of them have reported back that
3351 they're no longer running. */
3352 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3355 /* If we're not waiting for a specific LWP, choose an event LWP from
3356 among those that have had events. Giving equal priority to all
3357 LWPs that have had events helps prevent starvation. */
3358 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3359 select_event_lwp (ptid, &lp, &status);
3361 gdb_assert (lp != NULL);
3363 /* Now that we've selected our final event LWP, un-adjust its PC if
3364 it was a software breakpoint. */
3365 if (lp->stop_reason == LWP_STOPPED_BY_SW_BREAKPOINT)
3367 struct regcache *regcache = get_thread_regcache (lp->ptid);
3368 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3369 int decr_pc = target_decr_pc_after_break (gdbarch);
3375 pc = regcache_read_pc (regcache);
3376 regcache_write_pc (regcache, pc + decr_pc);
3380 /* We'll need this to determine whether to report a SIGSTOP as
3381 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3383 last_resume_kind = lp->last_resume_kind;
3387 /* In all-stop, from the core's perspective, all LWPs are now
3388 stopped until a new resume action is sent over. */
3389 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3393 resume_clear_callback (lp, NULL);
3396 if (linux_nat_status_is_event (status))
3398 if (debug_linux_nat)
3399 fprintf_unfiltered (gdb_stdlog,
3400 "LLW: trap ptid is %s.\n",
3401 target_pid_to_str (lp->ptid));
3404 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3406 *ourstatus = lp->waitstatus;
3407 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3410 store_waitstatus (ourstatus, status);
3412 if (debug_linux_nat)
3413 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3415 restore_child_signals_mask (&prev_mask);
3417 if (last_resume_kind == resume_stop
3418 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3419 && WSTOPSIG (status) == SIGSTOP)
3421 /* A thread that has been requested to stop by GDB with
3422 target_stop, and it stopped cleanly, so report as SIG0. The
3423 use of SIGSTOP is an implementation detail. */
3424 ourstatus->value.sig = GDB_SIGNAL_0;
3427 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3428 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3431 lp->core = linux_common_core_of_thread (lp->ptid);
3436 /* Resume LWPs that are currently stopped without any pending status
3437 to report, but are resumed from the core's perspective. */
3440 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3442 ptid_t *wait_ptid_p = data;
3446 && !lwp_status_pending_p (lp))
3448 struct regcache *regcache = get_thread_regcache (lp->ptid);
3449 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3450 CORE_ADDR pc = regcache_read_pc (regcache);
3452 /* Don't bother if there's a breakpoint at PC that we'd hit
3453 immediately, and we're not waiting for this LWP. */
3454 if (!ptid_match (lp->ptid, *wait_ptid_p))
3456 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3460 if (debug_linux_nat)
3461 fprintf_unfiltered (gdb_stdlog,
3462 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3463 target_pid_to_str (lp->ptid),
3464 paddress (gdbarch, pc),
3467 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3474 linux_nat_wait (struct target_ops *ops,
3475 ptid_t ptid, struct target_waitstatus *ourstatus,
3480 if (debug_linux_nat)
3482 char *options_string;
3484 options_string = target_options_to_string (target_options);
3485 fprintf_unfiltered (gdb_stdlog,
3486 "linux_nat_wait: [%s], [%s]\n",
3487 target_pid_to_str (ptid),
3489 xfree (options_string);
3492 /* Flush the async file first. */
3493 if (target_is_async_p ())
3494 async_file_flush ();
3496 /* Resume LWPs that are currently stopped without any pending status
3497 to report, but are resumed from the core's perspective. LWPs get
3498 in this state if we find them stopping at a time we're not
3499 interested in reporting the event (target_wait on a
3500 specific_process, for example, see linux_nat_wait_1), and
3501 meanwhile the event became uninteresting. Don't bother resuming
3502 LWPs we're not going to wait for if they'd stop immediately. */
3504 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3506 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3508 /* If we requested any event, and something came out, assume there
3509 may be more. If we requested a specific lwp or process, also
3510 assume there may be more. */
3511 if (target_is_async_p ()
3512 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3513 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3514 || !ptid_equal (ptid, minus_one_ptid)))
3521 kill_callback (struct lwp_info *lp, void *data)
3523 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3526 kill_lwp (ptid_get_lwp (lp->ptid), SIGKILL);
3527 if (debug_linux_nat)
3529 int save_errno = errno;
3531 fprintf_unfiltered (gdb_stdlog,
3532 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3533 target_pid_to_str (lp->ptid),
3534 save_errno ? safe_strerror (save_errno) : "OK");
3537 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3540 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3541 if (debug_linux_nat)
3543 int save_errno = errno;
3545 fprintf_unfiltered (gdb_stdlog,
3546 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3547 target_pid_to_str (lp->ptid),
3548 save_errno ? safe_strerror (save_errno) : "OK");
3555 kill_wait_callback (struct lwp_info *lp, void *data)
3559 /* We must make sure that there are no pending events (delayed
3560 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3561 program doesn't interfere with any following debugging session. */
3563 /* For cloned processes we must check both with __WCLONE and
3564 without, since the exit status of a cloned process isn't reported
3570 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3571 if (pid != (pid_t) -1)
3573 if (debug_linux_nat)
3574 fprintf_unfiltered (gdb_stdlog,
3575 "KWC: wait %s received unknown.\n",
3576 target_pid_to_str (lp->ptid));
3577 /* The Linux kernel sometimes fails to kill a thread
3578 completely after PTRACE_KILL; that goes from the stop
3579 point in do_fork out to the one in
3580 get_signal_to_deliever and waits again. So kill it
3582 kill_callback (lp, NULL);
3585 while (pid == ptid_get_lwp (lp->ptid));
3587 gdb_assert (pid == -1 && errno == ECHILD);
3592 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3593 if (pid != (pid_t) -1)
3595 if (debug_linux_nat)
3596 fprintf_unfiltered (gdb_stdlog,
3597 "KWC: wait %s received unk.\n",
3598 target_pid_to_str (lp->ptid));
3599 /* See the call to kill_callback above. */
3600 kill_callback (lp, NULL);
3603 while (pid == ptid_get_lwp (lp->ptid));
3605 gdb_assert (pid == -1 && errno == ECHILD);
3610 linux_nat_kill (struct target_ops *ops)
3612 struct target_waitstatus last;
3616 /* If we're stopped while forking and we haven't followed yet,
3617 kill the other task. We need to do this first because the
3618 parent will be sleeping if this is a vfork. */
3620 get_last_target_status (&last_ptid, &last);
3622 if (last.kind == TARGET_WAITKIND_FORKED
3623 || last.kind == TARGET_WAITKIND_VFORKED)
3625 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3628 /* Let the arch-specific native code know this process is
3630 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3633 if (forks_exist_p ())
3634 linux_fork_killall ();
3637 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3639 /* Stop all threads before killing them, since ptrace requires
3640 that the thread is stopped to sucessfully PTRACE_KILL. */
3641 iterate_over_lwps (ptid, stop_callback, NULL);
3642 /* ... and wait until all of them have reported back that
3643 they're no longer running. */
3644 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3646 /* Kill all LWP's ... */
3647 iterate_over_lwps (ptid, kill_callback, NULL);
3649 /* ... and wait until we've flushed all events. */
3650 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3653 target_mourn_inferior ();
3657 linux_nat_mourn_inferior (struct target_ops *ops)
3659 int pid = ptid_get_pid (inferior_ptid);
3661 purge_lwp_list (pid);
3663 if (! forks_exist_p ())
3664 /* Normal case, no other forks available. */
3665 linux_ops->to_mourn_inferior (ops);
3667 /* Multi-fork case. The current inferior_ptid has exited, but
3668 there are other viable forks to debug. Delete the exiting
3669 one and context-switch to the first available. */
3670 linux_fork_mourn_inferior ();
3672 /* Let the arch-specific native code know this process is gone. */
3673 linux_nat_forget_process (pid);
3676 /* Convert a native/host siginfo object, into/from the siginfo in the
3677 layout of the inferiors' architecture. */
3680 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3684 if (linux_nat_siginfo_fixup != NULL)
3685 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3687 /* If there was no callback, or the callback didn't do anything,
3688 then just do a straight memcpy. */
3692 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3694 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3698 static enum target_xfer_status
3699 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3700 const char *annex, gdb_byte *readbuf,
3701 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3702 ULONGEST *xfered_len)
3706 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3708 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3709 gdb_assert (readbuf || writebuf);
3711 pid = ptid_get_lwp (inferior_ptid);
3713 pid = ptid_get_pid (inferior_ptid);
3715 if (offset > sizeof (siginfo))
3716 return TARGET_XFER_E_IO;
3719 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3721 return TARGET_XFER_E_IO;
3723 /* When GDB is built as a 64-bit application, ptrace writes into
3724 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3725 inferior with a 64-bit GDB should look the same as debugging it
3726 with a 32-bit GDB, we need to convert it. GDB core always sees
3727 the converted layout, so any read/write will have to be done
3729 siginfo_fixup (&siginfo, inf_siginfo, 0);
3731 if (offset + len > sizeof (siginfo))
3732 len = sizeof (siginfo) - offset;
3734 if (readbuf != NULL)
3735 memcpy (readbuf, inf_siginfo + offset, len);
3738 memcpy (inf_siginfo + offset, writebuf, len);
3740 /* Convert back to ptrace layout before flushing it out. */
3741 siginfo_fixup (&siginfo, inf_siginfo, 1);
3744 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3746 return TARGET_XFER_E_IO;
3750 return TARGET_XFER_OK;
3753 static enum target_xfer_status
3754 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3755 const char *annex, gdb_byte *readbuf,
3756 const gdb_byte *writebuf,
3757 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3759 struct cleanup *old_chain;
3760 enum target_xfer_status xfer;
3762 if (object == TARGET_OBJECT_SIGNAL_INFO)
3763 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3764 offset, len, xfered_len);
3766 /* The target is connected but no live inferior is selected. Pass
3767 this request down to a lower stratum (e.g., the executable
3769 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3770 return TARGET_XFER_EOF;
3772 old_chain = save_inferior_ptid ();
3774 if (ptid_lwp_p (inferior_ptid))
3775 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3777 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3778 offset, len, xfered_len);
3780 do_cleanups (old_chain);
3785 linux_thread_alive (ptid_t ptid)
3789 gdb_assert (ptid_lwp_p (ptid));
3791 /* Send signal 0 instead of anything ptrace, because ptracing a
3792 running thread errors out claiming that the thread doesn't
3794 err = kill_lwp (ptid_get_lwp (ptid), 0);
3796 if (debug_linux_nat)
3797 fprintf_unfiltered (gdb_stdlog,
3798 "LLTA: KILL(SIG0) %s (%s)\n",
3799 target_pid_to_str (ptid),
3800 err ? safe_strerror (tmp_errno) : "OK");
3809 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3811 return linux_thread_alive (ptid);
3815 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3817 static char buf[64];
3819 if (ptid_lwp_p (ptid)
3820 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
3821 || num_lwps (ptid_get_pid (ptid)) > 1))
3823 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
3827 return normal_pid_to_str (ptid);
3831 linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
3833 int pid = ptid_get_pid (thr->ptid);
3834 long lwp = ptid_get_lwp (thr->ptid);
3835 #define FORMAT "/proc/%d/task/%ld/comm"
3836 char buf[sizeof (FORMAT) + 30];
3838 char *result = NULL;
3840 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
3841 comm_file = gdb_fopen_cloexec (buf, "r");
3844 /* Not exported by the kernel, so we define it here. */
3846 static char line[COMM_LEN + 1];
3848 if (fgets (line, sizeof (line), comm_file))
3850 char *nl = strchr (line, '\n');
3867 /* Accepts an integer PID; Returns a string representing a file that
3868 can be opened to get the symbols for the child process. */
3871 linux_child_pid_to_exec_file (struct target_ops *self, int pid)
3873 static char buf[PATH_MAX];
3874 char name[PATH_MAX];
3876 xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
3877 memset (buf, 0, PATH_MAX);
3878 if (readlink (name, buf, PATH_MAX - 1) <= 0)
3884 /* Implement the to_xfer_partial interface for memory reads using the /proc
3885 filesystem. Because we can use a single read() call for /proc, this
3886 can be much more efficient than banging away at PTRACE_PEEKTEXT,
3887 but it doesn't support writes. */
3889 static enum target_xfer_status
3890 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
3891 const char *annex, gdb_byte *readbuf,
3892 const gdb_byte *writebuf,
3893 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
3899 if (object != TARGET_OBJECT_MEMORY || !readbuf)
3902 /* Don't bother for one word. */
3903 if (len < 3 * sizeof (long))
3904 return TARGET_XFER_EOF;
3906 /* We could keep this file open and cache it - possibly one per
3907 thread. That requires some juggling, but is even faster. */
3908 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
3909 ptid_get_pid (inferior_ptid));
3910 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
3912 return TARGET_XFER_EOF;
3914 /* If pread64 is available, use it. It's faster if the kernel
3915 supports it (only one syscall), and it's 64-bit safe even on
3916 32-bit platforms (for instance, SPARC debugging a SPARC64
3919 if (pread64 (fd, readbuf, len, offset) != len)
3921 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
3930 return TARGET_XFER_EOF;
3934 return TARGET_XFER_OK;
3939 /* Enumerate spufs IDs for process PID. */
3941 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
3943 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
3945 LONGEST written = 0;
3948 struct dirent *entry;
3950 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
3951 dir = opendir (path);
3956 while ((entry = readdir (dir)) != NULL)
3962 fd = atoi (entry->d_name);
3966 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
3967 if (stat (path, &st) != 0)
3969 if (!S_ISDIR (st.st_mode))
3972 if (statfs (path, &stfs) != 0)
3974 if (stfs.f_type != SPUFS_MAGIC)
3977 if (pos >= offset && pos + 4 <= offset + len)
3979 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
3989 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
3990 object type, using the /proc file system. */
3992 static enum target_xfer_status
3993 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
3994 const char *annex, gdb_byte *readbuf,
3995 const gdb_byte *writebuf,
3996 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4001 int pid = ptid_get_pid (inferior_ptid);
4006 return TARGET_XFER_E_IO;
4009 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4012 return TARGET_XFER_E_IO;
4014 return TARGET_XFER_EOF;
4017 *xfered_len = (ULONGEST) l;
4018 return TARGET_XFER_OK;
4023 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4024 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4026 return TARGET_XFER_E_IO;
4029 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4032 return TARGET_XFER_EOF;
4036 ret = write (fd, writebuf, (size_t) len);
4038 ret = read (fd, readbuf, (size_t) len);
4043 return TARGET_XFER_E_IO;
4045 return TARGET_XFER_EOF;
4048 *xfered_len = (ULONGEST) ret;
4049 return TARGET_XFER_OK;
4054 /* Parse LINE as a signal set and add its set bits to SIGS. */
4057 add_line_to_sigset (const char *line, sigset_t *sigs)
4059 int len = strlen (line) - 1;
4063 if (line[len] != '\n')
4064 error (_("Could not parse signal set: %s"), line);
4072 if (*p >= '0' && *p <= '9')
4074 else if (*p >= 'a' && *p <= 'f')
4075 digit = *p - 'a' + 10;
4077 error (_("Could not parse signal set: %s"), line);
4082 sigaddset (sigs, signum + 1);
4084 sigaddset (sigs, signum + 2);
4086 sigaddset (sigs, signum + 3);
4088 sigaddset (sigs, signum + 4);
4094 /* Find process PID's pending signals from /proc/pid/status and set
4098 linux_proc_pending_signals (int pid, sigset_t *pending,
4099 sigset_t *blocked, sigset_t *ignored)
4102 char buffer[PATH_MAX], fname[PATH_MAX];
4103 struct cleanup *cleanup;
4105 sigemptyset (pending);
4106 sigemptyset (blocked);
4107 sigemptyset (ignored);
4108 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4109 procfile = gdb_fopen_cloexec (fname, "r");
4110 if (procfile == NULL)
4111 error (_("Could not open %s"), fname);
4112 cleanup = make_cleanup_fclose (procfile);
4114 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4116 /* Normal queued signals are on the SigPnd line in the status
4117 file. However, 2.6 kernels also have a "shared" pending
4118 queue for delivering signals to a thread group, so check for
4121 Unfortunately some Red Hat kernels include the shared pending
4122 queue but not the ShdPnd status field. */
4124 if (strncmp (buffer, "SigPnd:\t", 8) == 0)
4125 add_line_to_sigset (buffer + 8, pending);
4126 else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
4127 add_line_to_sigset (buffer + 8, pending);
4128 else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
4129 add_line_to_sigset (buffer + 8, blocked);
4130 else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
4131 add_line_to_sigset (buffer + 8, ignored);
4134 do_cleanups (cleanup);
4137 static enum target_xfer_status
4138 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4139 const char *annex, gdb_byte *readbuf,
4140 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4141 ULONGEST *xfered_len)
4143 gdb_assert (object == TARGET_OBJECT_OSDATA);
4145 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4146 if (*xfered_len == 0)
4147 return TARGET_XFER_EOF;
4149 return TARGET_XFER_OK;
4152 static enum target_xfer_status
4153 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4154 const char *annex, gdb_byte *readbuf,
4155 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4156 ULONGEST *xfered_len)
4158 enum target_xfer_status xfer;
4160 if (object == TARGET_OBJECT_AUXV)
4161 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4162 offset, len, xfered_len);
4164 if (object == TARGET_OBJECT_OSDATA)
4165 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4166 offset, len, xfered_len);
4168 if (object == TARGET_OBJECT_SPU)
4169 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4170 offset, len, xfered_len);
4172 /* GDB calculates all the addresses in possibly larget width of the address.
4173 Address width needs to be masked before its final use - either by
4174 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4176 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4178 if (object == TARGET_OBJECT_MEMORY)
4180 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4182 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4183 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4186 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4187 offset, len, xfered_len);
4188 if (xfer != TARGET_XFER_EOF)
4191 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4192 offset, len, xfered_len);
4196 cleanup_target_stop (void *arg)
4198 ptid_t *ptid = (ptid_t *) arg;
4200 gdb_assert (arg != NULL);
4203 target_resume (*ptid, 0, GDB_SIGNAL_0);
4206 static VEC(static_tracepoint_marker_p) *
4207 linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
4210 char s[IPA_CMD_BUF_SIZE];
4211 struct cleanup *old_chain;
4212 int pid = ptid_get_pid (inferior_ptid);
4213 VEC(static_tracepoint_marker_p) *markers = NULL;
4214 struct static_tracepoint_marker *marker = NULL;
4216 ptid_t ptid = ptid_build (pid, 0, 0);
4221 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4222 s[sizeof ("qTfSTM")] = 0;
4224 agent_run_command (pid, s, strlen (s) + 1);
4226 old_chain = make_cleanup (free_current_marker, &marker);
4227 make_cleanup (cleanup_target_stop, &ptid);
4232 marker = XCNEW (struct static_tracepoint_marker);
4236 parse_static_tracepoint_marker_definition (p, &p, marker);
4238 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4240 VEC_safe_push (static_tracepoint_marker_p,
4246 release_static_tracepoint_marker (marker);
4247 memset (marker, 0, sizeof (*marker));
4250 while (*p++ == ','); /* comma-separated list */
4252 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4253 s[sizeof ("qTsSTM")] = 0;
4254 agent_run_command (pid, s, strlen (s) + 1);
4258 do_cleanups (old_chain);
4263 /* Create a prototype generic GNU/Linux target. The client can override
4264 it with local methods. */
4267 linux_target_install_ops (struct target_ops *t)
4269 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4270 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4271 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4272 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4273 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4274 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4275 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4276 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4277 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4278 t->to_post_attach = linux_child_post_attach;
4279 t->to_follow_fork = linux_child_follow_fork;
4281 super_xfer_partial = t->to_xfer_partial;
4282 t->to_xfer_partial = linux_xfer_partial;
4284 t->to_static_tracepoint_markers_by_strid
4285 = linux_child_static_tracepoint_markers_by_strid;
4291 struct target_ops *t;
4293 t = inf_ptrace_target ();
4294 linux_target_install_ops (t);
4300 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4302 struct target_ops *t;
4304 t = inf_ptrace_trad_target (register_u_offset);
4305 linux_target_install_ops (t);
4310 /* target_is_async_p implementation. */
4313 linux_nat_is_async_p (struct target_ops *ops)
4315 return linux_is_async_p ();
4318 /* target_can_async_p implementation. */
4321 linux_nat_can_async_p (struct target_ops *ops)
4323 /* NOTE: palves 2008-03-21: We're only async when the user requests
4324 it explicitly with the "set target-async" command.
4325 Someday, linux will always be async. */
4326 return target_async_permitted;
4330 linux_nat_supports_non_stop (struct target_ops *self)
4335 /* True if we want to support multi-process. To be removed when GDB
4336 supports multi-exec. */
4338 int linux_multi_process = 1;
4341 linux_nat_supports_multi_process (struct target_ops *self)
4343 return linux_multi_process;
4347 linux_nat_supports_disable_randomization (struct target_ops *self)
4349 #ifdef HAVE_PERSONALITY
4356 static int async_terminal_is_ours = 1;
4358 /* target_terminal_inferior implementation.
4360 This is a wrapper around child_terminal_inferior to add async support. */
4363 linux_nat_terminal_inferior (struct target_ops *self)
4365 /* Like target_terminal_inferior, use target_can_async_p, not
4366 target_is_async_p, since at this point the target is not async
4367 yet. If it can async, then we know it will become async prior to
4369 if (!target_can_async_p ())
4371 /* Async mode is disabled. */
4372 child_terminal_inferior (self);
4376 child_terminal_inferior (self);
4378 /* Calls to target_terminal_*() are meant to be idempotent. */
4379 if (!async_terminal_is_ours)
4382 delete_file_handler (input_fd);
4383 async_terminal_is_ours = 0;
4387 /* target_terminal_ours implementation.
4389 This is a wrapper around child_terminal_ours to add async support (and
4390 implement the target_terminal_ours vs target_terminal_ours_for_output
4391 distinction). child_terminal_ours is currently no different than
4392 child_terminal_ours_for_output.
4393 We leave target_terminal_ours_for_output alone, leaving it to
4394 child_terminal_ours_for_output. */
4397 linux_nat_terminal_ours (struct target_ops *self)
4399 /* GDB should never give the terminal to the inferior if the
4400 inferior is running in the background (run&, continue&, etc.),
4401 but claiming it sure should. */
4402 child_terminal_ours (self);
4404 if (async_terminal_is_ours)
4407 clear_sigint_trap ();
4408 add_file_handler (input_fd, stdin_event_handler, 0);
4409 async_terminal_is_ours = 1;
4412 static void (*async_client_callback) (enum inferior_event_type event_type,
4414 static void *async_client_context;
4416 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4417 so we notice when any child changes state, and notify the
4418 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4419 above to wait for the arrival of a SIGCHLD. */
4422 sigchld_handler (int signo)
4424 int old_errno = errno;
4426 if (debug_linux_nat)
4427 ui_file_write_async_safe (gdb_stdlog,
4428 "sigchld\n", sizeof ("sigchld\n") - 1);
4430 if (signo == SIGCHLD
4431 && linux_nat_event_pipe[0] != -1)
4432 async_file_mark (); /* Let the event loop know that there are
4433 events to handle. */
4438 /* Callback registered with the target events file descriptor. */
4441 handle_target_event (int error, gdb_client_data client_data)
4443 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4446 /* Create/destroy the target events pipe. Returns previous state. */
4449 linux_async_pipe (int enable)
4451 int previous = linux_is_async_p ();
4453 if (previous != enable)
4457 /* Block child signals while we create/destroy the pipe, as
4458 their handler writes to it. */
4459 block_child_signals (&prev_mask);
4463 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4464 internal_error (__FILE__, __LINE__,
4465 "creating event pipe failed.");
4467 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4468 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4472 close (linux_nat_event_pipe[0]);
4473 close (linux_nat_event_pipe[1]);
4474 linux_nat_event_pipe[0] = -1;
4475 linux_nat_event_pipe[1] = -1;
4478 restore_child_signals_mask (&prev_mask);
4484 /* target_async implementation. */
4487 linux_nat_async (struct target_ops *ops,
4488 void (*callback) (enum inferior_event_type event_type,
4492 if (callback != NULL)
4494 async_client_callback = callback;
4495 async_client_context = context;
4496 if (!linux_async_pipe (1))
4498 add_file_handler (linux_nat_event_pipe[0],
4499 handle_target_event, NULL);
4500 /* There may be pending events to handle. Tell the event loop
4507 async_client_callback = callback;
4508 async_client_context = context;
4509 delete_file_handler (linux_nat_event_pipe[0]);
4510 linux_async_pipe (0);
4515 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4519 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4523 if (debug_linux_nat)
4524 fprintf_unfiltered (gdb_stdlog,
4525 "LNSL: running -> suspending %s\n",
4526 target_pid_to_str (lwp->ptid));
4529 if (lwp->last_resume_kind == resume_stop)
4531 if (debug_linux_nat)
4532 fprintf_unfiltered (gdb_stdlog,
4533 "linux-nat: already stopping LWP %ld at "
4535 ptid_get_lwp (lwp->ptid));
4539 stop_callback (lwp, NULL);
4540 lwp->last_resume_kind = resume_stop;
4544 /* Already known to be stopped; do nothing. */
4546 if (debug_linux_nat)
4548 if (find_thread_ptid (lwp->ptid)->stop_requested)
4549 fprintf_unfiltered (gdb_stdlog,
4550 "LNSL: already stopped/stop_requested %s\n",
4551 target_pid_to_str (lwp->ptid));
4553 fprintf_unfiltered (gdb_stdlog,
4554 "LNSL: already stopped/no "
4555 "stop_requested yet %s\n",
4556 target_pid_to_str (lwp->ptid));
4563 linux_nat_stop (struct target_ops *self, ptid_t ptid)
4566 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4568 linux_ops->to_stop (linux_ops, ptid);
4572 linux_nat_close (struct target_ops *self)
4574 /* Unregister from the event loop. */
4575 if (linux_nat_is_async_p (self))
4576 linux_nat_async (self, NULL, NULL);
4578 if (linux_ops->to_close)
4579 linux_ops->to_close (linux_ops);
4584 /* When requests are passed down from the linux-nat layer to the
4585 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4586 used. The address space pointer is stored in the inferior object,
4587 but the common code that is passed such ptid can't tell whether
4588 lwpid is a "main" process id or not (it assumes so). We reverse
4589 look up the "main" process id from the lwp here. */
4591 static struct address_space *
4592 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4594 struct lwp_info *lwp;
4595 struct inferior *inf;
4598 if (ptid_get_lwp (ptid) == 0)
4600 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4602 lwp = find_lwp_pid (ptid);
4603 pid = ptid_get_pid (lwp->ptid);
4607 /* A (pid,lwpid,0) ptid. */
4608 pid = ptid_get_pid (ptid);
4611 inf = find_inferior_pid (pid);
4612 gdb_assert (inf != NULL);
4616 /* Return the cached value of the processor core for thread PTID. */
4619 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4621 struct lwp_info *info = find_lwp_pid (ptid);
4629 linux_nat_add_target (struct target_ops *t)
4631 /* Save the provided single-threaded target. We save this in a separate
4632 variable because another target we've inherited from (e.g. inf-ptrace)
4633 may have saved a pointer to T; we want to use it for the final
4634 process stratum target. */
4635 linux_ops_saved = *t;
4636 linux_ops = &linux_ops_saved;
4638 /* Override some methods for multithreading. */
4639 t->to_create_inferior = linux_nat_create_inferior;
4640 t->to_attach = linux_nat_attach;
4641 t->to_detach = linux_nat_detach;
4642 t->to_resume = linux_nat_resume;
4643 t->to_wait = linux_nat_wait;
4644 t->to_pass_signals = linux_nat_pass_signals;
4645 t->to_xfer_partial = linux_nat_xfer_partial;
4646 t->to_kill = linux_nat_kill;
4647 t->to_mourn_inferior = linux_nat_mourn_inferior;
4648 t->to_thread_alive = linux_nat_thread_alive;
4649 t->to_pid_to_str = linux_nat_pid_to_str;
4650 t->to_thread_name = linux_nat_thread_name;
4651 t->to_has_thread_control = tc_schedlock;
4652 t->to_thread_address_space = linux_nat_thread_address_space;
4653 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4654 t->to_stopped_data_address = linux_nat_stopped_data_address;
4656 t->to_can_async_p = linux_nat_can_async_p;
4657 t->to_is_async_p = linux_nat_is_async_p;
4658 t->to_supports_non_stop = linux_nat_supports_non_stop;
4659 t->to_async = linux_nat_async;
4660 t->to_terminal_inferior = linux_nat_terminal_inferior;
4661 t->to_terminal_ours = linux_nat_terminal_ours;
4663 super_close = t->to_close;
4664 t->to_close = linux_nat_close;
4666 /* Methods for non-stop support. */
4667 t->to_stop = linux_nat_stop;
4669 t->to_supports_multi_process = linux_nat_supports_multi_process;
4671 t->to_supports_disable_randomization
4672 = linux_nat_supports_disable_randomization;
4674 t->to_core_of_thread = linux_nat_core_of_thread;
4676 /* We don't change the stratum; this target will sit at
4677 process_stratum and thread_db will set at thread_stratum. This
4678 is a little strange, since this is a multi-threaded-capable
4679 target, but we want to be on the stack below thread_db, and we
4680 also want to be used for single-threaded processes. */
4685 /* Register a method to call whenever a new thread is attached. */
4687 linux_nat_set_new_thread (struct target_ops *t,
4688 void (*new_thread) (struct lwp_info *))
4690 /* Save the pointer. We only support a single registered instance
4691 of the GNU/Linux native target, so we do not need to map this to
4693 linux_nat_new_thread = new_thread;
4696 /* See declaration in linux-nat.h. */
4699 linux_nat_set_new_fork (struct target_ops *t,
4700 linux_nat_new_fork_ftype *new_fork)
4702 /* Save the pointer. */
4703 linux_nat_new_fork = new_fork;
4706 /* See declaration in linux-nat.h. */
4709 linux_nat_set_forget_process (struct target_ops *t,
4710 linux_nat_forget_process_ftype *fn)
4712 /* Save the pointer. */
4713 linux_nat_forget_process_hook = fn;
4716 /* See declaration in linux-nat.h. */
4719 linux_nat_forget_process (pid_t pid)
4721 if (linux_nat_forget_process_hook != NULL)
4722 linux_nat_forget_process_hook (pid);
4725 /* Register a method that converts a siginfo object between the layout
4726 that ptrace returns, and the layout in the architecture of the
4729 linux_nat_set_siginfo_fixup (struct target_ops *t,
4730 int (*siginfo_fixup) (siginfo_t *,
4734 /* Save the pointer. */
4735 linux_nat_siginfo_fixup = siginfo_fixup;
4738 /* Register a method to call prior to resuming a thread. */
4741 linux_nat_set_prepare_to_resume (struct target_ops *t,
4742 void (*prepare_to_resume) (struct lwp_info *))
4744 /* Save the pointer. */
4745 linux_nat_prepare_to_resume = prepare_to_resume;
4748 /* See linux-nat.h. */
4751 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4755 pid = ptid_get_lwp (ptid);
4757 pid = ptid_get_pid (ptid);
4760 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4763 memset (siginfo, 0, sizeof (*siginfo));
4769 /* Provide a prototype to silence -Wmissing-prototypes. */
4770 extern initialize_file_ftype _initialize_linux_nat;
4773 _initialize_linux_nat (void)
4775 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4776 &debug_linux_nat, _("\
4777 Set debugging of GNU/Linux lwp module."), _("\
4778 Show debugging of GNU/Linux lwp module."), _("\
4779 Enables printf debugging output."),
4781 show_debug_linux_nat,
4782 &setdebuglist, &showdebuglist);
4784 /* Save this mask as the default. */
4785 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4787 /* Install a SIGCHLD handler. */
4788 sigchld_action.sa_handler = sigchld_handler;
4789 sigemptyset (&sigchld_action.sa_mask);
4790 sigchld_action.sa_flags = SA_RESTART;
4792 /* Make it the default. */
4793 sigaction (SIGCHLD, &sigchld_action, NULL);
4795 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4796 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
4797 sigdelset (&suspend_mask, SIGCHLD);
4799 sigemptyset (&blocked_mask);
4801 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
4802 support read-only process state. */
4803 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
4804 | PTRACE_O_TRACEVFORKDONE
4805 | PTRACE_O_TRACEVFORK
4806 | PTRACE_O_TRACEFORK
4807 | PTRACE_O_TRACEEXEC);
4811 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4812 the GNU/Linux Threads library and therefore doesn't really belong
4815 /* Read variable NAME in the target and return its value if found.
4816 Otherwise return zero. It is assumed that the type of the variable
4820 get_signo (const char *name)
4822 struct bound_minimal_symbol ms;
4825 ms = lookup_minimal_symbol (name, NULL, NULL);
4826 if (ms.minsym == NULL)
4829 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
4830 sizeof (signo)) != 0)
4836 /* Return the set of signals used by the threads library in *SET. */
4839 lin_thread_get_thread_signals (sigset_t *set)
4841 struct sigaction action;
4842 int restart, cancel;
4844 sigemptyset (&blocked_mask);
4847 restart = get_signo ("__pthread_sig_restart");
4848 cancel = get_signo ("__pthread_sig_cancel");
4850 /* LinuxThreads normally uses the first two RT signals, but in some legacy
4851 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
4852 not provide any way for the debugger to query the signal numbers -
4853 fortunately they don't change! */
4856 restart = __SIGRTMIN;
4859 cancel = __SIGRTMIN + 1;
4861 sigaddset (set, restart);
4862 sigaddset (set, cancel);
4864 /* The GNU/Linux Threads library makes terminating threads send a
4865 special "cancel" signal instead of SIGCHLD. Make sure we catch
4866 those (to prevent them from terminating GDB itself, which is
4867 likely to be their default action) and treat them the same way as
4870 action.sa_handler = sigchld_handler;
4871 sigemptyset (&action.sa_mask);
4872 action.sa_flags = SA_RESTART;
4873 sigaction (cancel, &action, NULL);
4875 /* We block the "cancel" signal throughout this code ... */
4876 sigaddset (&blocked_mask, cancel);
4877 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
4879 /* ... except during a sigsuspend. */
4880 sigdelset (&suspend_mask, cancel);