1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2018 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
28 #include <sys/syscall.h>
29 #include "nat/gdb_ptrace.h"
30 #include "linux-nat.h"
31 #include "nat/linux-ptrace.h"
32 #include "nat/linux-procfs.h"
33 #include "nat/linux-personality.h"
34 #include "linux-fork.h"
35 #include "gdbthread.h"
39 #include "inf-child.h"
40 #include "inf-ptrace.h"
42 #include <sys/procfs.h> /* for elf_gregset etc. */
43 #include "elf-bfd.h" /* for elfcore_write_* */
44 #include "gregset.h" /* for gregset */
45 #include "gdbcore.h" /* for get_exec_file */
46 #include <ctype.h> /* for isdigit */
47 #include <sys/stat.h> /* for struct stat */
48 #include <fcntl.h> /* for O_RDONLY */
50 #include "event-loop.h"
51 #include "event-top.h"
53 #include <sys/types.h>
55 #include "xml-support.h"
58 #include "nat/linux-osdata.h"
59 #include "linux-tdep.h"
62 #include "tracepoint.h"
64 #include "target-descriptions.h"
65 #include "filestuff.h"
67 #include "nat/linux-namespaces.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,
80 passing the specific pid, and not passing WNOHANG.
82 When waiting for an event in all threads, waitpid is not quite good:
84 - If the thread group leader exits while other threads in the thread
85 group still exist, waitpid(TGID, ...) hangs. That waitpid won't
86 return an exit status until the other threads in the group are
89 - When a non-leader thread execs, that thread just vanishes without
90 reporting an exit (so we'd hang if we waited for it explicitly in
91 that case). The exec event is instead reported to the TGID pid.
93 The solution is to always use -1 and WNOHANG, together with
96 First, we use non-blocking waitpid to check for events. If nothing is
97 found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives,
98 it means something happened to a child process. As soon as we know
99 there's an event, we get back to calling nonblocking waitpid.
101 Note that SIGCHLD should be blocked between waitpid and sigsuspend
102 calls, so that we don't miss a signal. If SIGCHLD arrives in between,
103 when it's blocked, the signal becomes pending and sigsuspend
104 immediately notices it and returns.
106 Waiting for events in async mode (TARGET_WNOHANG)
107 =================================================
109 In async mode, GDB should always be ready to handle both user input
110 and target events, so neither blocking waitpid nor sigsuspend are
111 viable options. Instead, we should asynchronously notify the GDB main
112 event loop whenever there's an unprocessed event from the target. We
113 detect asynchronous target events by handling SIGCHLD signals. To
114 notify the event loop about target events, the self-pipe trick is used
115 --- a pipe is registered as waitable event source in the event loop,
116 the event loop select/poll's on the read end of this pipe (as well on
117 other event sources, e.g., stdin), and the SIGCHLD handler writes a
118 byte to this pipe. This is more portable than relying on
119 pselect/ppoll, since on kernels that lack those syscalls, libc
120 emulates them with select/poll+sigprocmask, and that is racy
121 (a.k.a. plain broken).
123 Obviously, if we fail to notify the event loop if there's a target
124 event, it's bad. OTOH, if we notify the event loop when there's no
125 event from the target, linux_nat_wait will detect that there's no real
126 event to report, and return event of type TARGET_WAITKIND_IGNORE.
127 This is mostly harmless, but it will waste time and is better avoided.
129 The main design point is that every time GDB is outside linux-nat.c,
130 we have a SIGCHLD handler installed that is called when something
131 happens to the target and notifies the GDB event loop. Whenever GDB
132 core decides to handle the event, and calls into linux-nat.c, we
133 process things as in sync mode, except that the we never block in
136 While processing an event, we may end up momentarily blocked in
137 waitpid calls. Those waitpid calls, while blocking, are guarantied to
138 return quickly. E.g., in all-stop mode, before reporting to the core
139 that an LWP hit a breakpoint, all LWPs are stopped by sending them
140 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
141 Note that this is different from blocking indefinitely waiting for the
142 next event --- here, we're already handling an event.
147 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
148 signal is not entirely significant; we just need for a signal to be delivered,
149 so that we can intercept it. SIGSTOP's advantage is that it can not be
150 blocked. A disadvantage is that it is not a real-time signal, so it can only
151 be queued once; we do not keep track of other sources of SIGSTOP.
153 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
154 use them, because they have special behavior when the signal is generated -
155 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
156 kills the entire thread group.
158 A delivered SIGSTOP would stop the entire thread group, not just the thread we
159 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
160 cancel it (by PTRACE_CONT without passing SIGSTOP).
162 We could use a real-time signal instead. This would solve those problems; we
163 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
164 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
165 generates it, and there are races with trying to find a signal that is not
171 The case of a thread group (process) with 3 or more threads, and a
172 thread other than the leader execs is worth detailing:
174 On an exec, the Linux kernel destroys all threads except the execing
175 one in the thread group, and resets the execing thread's tid to the
176 tgid. No exit notification is sent for the execing thread -- from the
177 ptracer's perspective, it appears as though the execing thread just
178 vanishes. Until we reap all other threads except the leader and the
179 execing thread, the leader will be zombie, and the execing thread will
180 be in `D (disc sleep)' state. As soon as all other threads are
181 reaped, the execing thread changes its tid to the tgid, and the
182 previous (zombie) leader vanishes, giving place to the "new"
186 #define O_LARGEFILE 0
189 struct linux_nat_target *linux_target;
191 /* Does the current host support PTRACE_GETREGSET? */
192 enum tribool have_ptrace_getregset = TRIBOOL_UNKNOWN;
194 /* The saved to_close method, inherited from inf-ptrace.c.
195 Called by our to_close. */
196 static void (*super_close) (struct target_ops *);
198 static unsigned int debug_linux_nat;
200 show_debug_linux_nat (struct ui_file *file, int from_tty,
201 struct cmd_list_element *c, const char *value)
203 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
207 struct simple_pid_list
211 struct simple_pid_list *next;
213 struct simple_pid_list *stopped_pids;
215 /* Whether target_thread_events is in effect. */
216 static int report_thread_events;
218 /* Async mode support. */
220 /* The read/write ends of the pipe registered as waitable file in the
222 static int linux_nat_event_pipe[2] = { -1, -1 };
224 /* True if we're currently in async mode. */
225 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
227 /* Flush the event pipe. */
230 async_file_flush (void)
237 ret = read (linux_nat_event_pipe[0], &buf, 1);
239 while (ret >= 0 || (ret == -1 && errno == EINTR));
242 /* Put something (anything, doesn't matter what, or how much) in event
243 pipe, so that the select/poll in the event-loop realizes we have
244 something to process. */
247 async_file_mark (void)
251 /* It doesn't really matter what the pipe contains, as long we end
252 up with something in it. Might as well flush the previous
258 ret = write (linux_nat_event_pipe[1], "+", 1);
260 while (ret == -1 && errno == EINTR);
262 /* Ignore EAGAIN. If the pipe is full, the event loop will already
263 be awakened anyway. */
266 static int kill_lwp (int lwpid, int signo);
268 static int stop_callback (struct lwp_info *lp, void *data);
269 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
271 static void block_child_signals (sigset_t *prev_mask);
272 static void restore_child_signals_mask (sigset_t *prev_mask);
275 static struct lwp_info *add_lwp (ptid_t ptid);
276 static void purge_lwp_list (int pid);
277 static void delete_lwp (ptid_t ptid);
278 static struct lwp_info *find_lwp_pid (ptid_t ptid);
280 static int lwp_status_pending_p (struct lwp_info *lp);
282 static void save_stop_reason (struct lwp_info *lp);
287 /* See nat/linux-nat.h. */
290 ptid_of_lwp (struct lwp_info *lwp)
295 /* See nat/linux-nat.h. */
298 lwp_set_arch_private_info (struct lwp_info *lwp,
299 struct arch_lwp_info *info)
301 lwp->arch_private = info;
304 /* See nat/linux-nat.h. */
306 struct arch_lwp_info *
307 lwp_arch_private_info (struct lwp_info *lwp)
309 return lwp->arch_private;
312 /* See nat/linux-nat.h. */
315 lwp_is_stopped (struct lwp_info *lwp)
320 /* See nat/linux-nat.h. */
322 enum target_stop_reason
323 lwp_stop_reason (struct lwp_info *lwp)
325 return lwp->stop_reason;
328 /* See nat/linux-nat.h. */
331 lwp_is_stepping (struct lwp_info *lwp)
337 /* Trivial list manipulation functions to keep track of a list of
338 new stopped processes. */
340 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
342 struct simple_pid_list *new_pid = XNEW (struct simple_pid_list);
345 new_pid->status = status;
346 new_pid->next = *listp;
351 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
353 struct simple_pid_list **p;
355 for (p = listp; *p != NULL; p = &(*p)->next)
356 if ((*p)->pid == pid)
358 struct simple_pid_list *next = (*p)->next;
360 *statusp = (*p)->status;
368 /* Return the ptrace options that we want to try to enable. */
371 linux_nat_ptrace_options (int attached)
376 options |= PTRACE_O_EXITKILL;
378 options |= (PTRACE_O_TRACESYSGOOD
379 | PTRACE_O_TRACEVFORKDONE
380 | PTRACE_O_TRACEVFORK
382 | PTRACE_O_TRACEEXEC);
387 /* Initialize ptrace and procfs warnings and check for supported
388 ptrace features given PID.
390 ATTACHED should be nonzero iff we attached to the inferior. */
393 linux_init_ptrace_procfs (pid_t pid, int attached)
395 int options = linux_nat_ptrace_options (attached);
397 linux_enable_event_reporting (pid, options);
398 linux_ptrace_init_warnings ();
399 linux_proc_init_warnings ();
402 linux_nat_target::~linux_nat_target ()
406 linux_nat_target::post_attach (int pid)
408 linux_init_ptrace_procfs (pid, 1);
412 linux_nat_target::post_startup_inferior (ptid_t ptid)
414 linux_init_ptrace_procfs (ptid.pid (), 0);
417 /* Return the number of known LWPs in the tgid given by PID. */
425 for (lp = lwp_list; lp; lp = lp->next)
426 if (lp->ptid.pid () == pid)
432 /* Call delete_lwp with prototype compatible for make_cleanup. */
435 delete_lwp_cleanup (void *lp_voidp)
437 struct lwp_info *lp = (struct lwp_info *) lp_voidp;
439 delete_lwp (lp->ptid);
442 /* Target hook for follow_fork. On entry inferior_ptid must be the
443 ptid of the followed inferior. At return, inferior_ptid will be
447 linux_nat_target::follow_fork (int follow_child, int detach_fork)
451 struct lwp_info *child_lp = NULL;
452 int status = W_STOPCODE (0);
454 ptid_t parent_ptid, child_ptid;
455 int parent_pid, child_pid;
457 has_vforked = (inferior_thread ()->pending_follow.kind
458 == TARGET_WAITKIND_VFORKED);
459 parent_ptid = inferior_ptid;
460 child_ptid = inferior_thread ()->pending_follow.value.related_pid;
461 parent_pid = parent_ptid.lwp ();
462 child_pid = child_ptid.lwp ();
464 /* We're already attached to the parent, by default. */
465 child_lp = add_lwp (child_ptid);
466 child_lp->stopped = 1;
467 child_lp->last_resume_kind = resume_stop;
469 /* Detach new forked process? */
472 struct cleanup *old_chain = make_cleanup (delete_lwp_cleanup,
475 linux_target->low_prepare_to_resume (child_lp);
477 /* When debugging an inferior in an architecture that supports
478 hardware single stepping on a kernel without commit
479 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
480 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
481 set if the parent process had them set.
482 To work around this, single step the child process
483 once before detaching to clear the flags. */
485 /* Note that we consult the parent's architecture instead of
486 the child's because there's no inferior for the child at
488 if (!gdbarch_software_single_step_p (target_thread_architecture
491 linux_disable_event_reporting (child_pid);
492 if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
493 perror_with_name (_("Couldn't do single step"));
494 if (my_waitpid (child_pid, &status, 0) < 0)
495 perror_with_name (_("Couldn't wait vfork process"));
498 if (WIFSTOPPED (status))
502 signo = WSTOPSIG (status);
504 && !signal_pass_state (gdb_signal_from_host (signo)))
506 ptrace (PTRACE_DETACH, child_pid, 0, signo);
509 do_cleanups (old_chain);
513 scoped_restore save_inferior_ptid
514 = make_scoped_restore (&inferior_ptid);
515 inferior_ptid = child_ptid;
517 /* Let the thread_db layer learn about this new process. */
518 check_for_thread_db ();
523 struct lwp_info *parent_lp;
525 parent_lp = find_lwp_pid (parent_ptid);
526 gdb_assert (linux_supports_tracefork () >= 0);
528 if (linux_supports_tracevforkdone ())
531 fprintf_unfiltered (gdb_stdlog,
532 "LCFF: waiting for VFORK_DONE on %d\n",
534 parent_lp->stopped = 1;
536 /* We'll handle the VFORK_DONE event like any other
537 event, in target_wait. */
541 /* We can't insert breakpoints until the child has
542 finished with the shared memory region. We need to
543 wait until that happens. Ideal would be to just
545 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
546 - waitpid (parent_pid, &status, __WALL);
547 However, most architectures can't handle a syscall
548 being traced on the way out if it wasn't traced on
551 We might also think to loop, continuing the child
552 until it exits or gets a SIGTRAP. One problem is
553 that the child might call ptrace with PTRACE_TRACEME.
555 There's no simple and reliable way to figure out when
556 the vforked child will be done with its copy of the
557 shared memory. We could step it out of the syscall,
558 two instructions, let it go, and then single-step the
559 parent once. When we have hardware single-step, this
560 would work; with software single-step it could still
561 be made to work but we'd have to be able to insert
562 single-step breakpoints in the child, and we'd have
563 to insert -just- the single-step breakpoint in the
564 parent. Very awkward.
566 In the end, the best we can do is to make sure it
567 runs for a little while. Hopefully it will be out of
568 range of any breakpoints we reinsert. Usually this
569 is only the single-step breakpoint at vfork's return
573 fprintf_unfiltered (gdb_stdlog,
574 "LCFF: no VFORK_DONE "
575 "support, sleeping a bit\n");
579 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
580 and leave it pending. The next linux_nat_resume call
581 will notice a pending event, and bypasses actually
582 resuming the inferior. */
583 parent_lp->status = 0;
584 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
585 parent_lp->stopped = 1;
587 /* If we're in async mode, need to tell the event loop
588 there's something here to process. */
589 if (target_is_async_p ())
596 struct lwp_info *child_lp;
598 child_lp = add_lwp (inferior_ptid);
599 child_lp->stopped = 1;
600 child_lp->last_resume_kind = resume_stop;
602 /* Let the thread_db layer learn about this new process. */
603 check_for_thread_db ();
611 linux_nat_target::insert_fork_catchpoint (int pid)
613 return !linux_supports_tracefork ();
617 linux_nat_target::remove_fork_catchpoint (int pid)
623 linux_nat_target::insert_vfork_catchpoint (int pid)
625 return !linux_supports_tracefork ();
629 linux_nat_target::remove_vfork_catchpoint (int pid)
635 linux_nat_target::insert_exec_catchpoint (int pid)
637 return !linux_supports_tracefork ();
641 linux_nat_target::remove_exec_catchpoint (int pid)
647 linux_nat_target::set_syscall_catchpoint (int pid, bool needed, int any_count,
648 gdb::array_view<const int> syscall_counts)
650 if (!linux_supports_tracesysgood ())
653 /* On GNU/Linux, we ignore the arguments. It means that we only
654 enable the syscall catchpoints, but do not disable them.
656 Also, we do not use the `syscall_counts' information because we do not
657 filter system calls here. We let GDB do the logic for us. */
661 /* List of known LWPs, keyed by LWP PID. This speeds up the common
662 case of mapping a PID returned from the kernel to our corresponding
663 lwp_info data structure. */
664 static htab_t lwp_lwpid_htab;
666 /* Calculate a hash from a lwp_info's LWP PID. */
669 lwp_info_hash (const void *ap)
671 const struct lwp_info *lp = (struct lwp_info *) ap;
672 pid_t pid = lp->ptid.lwp ();
674 return iterative_hash_object (pid, 0);
677 /* Equality function for the lwp_info hash table. Compares the LWP's
681 lwp_lwpid_htab_eq (const void *a, const void *b)
683 const struct lwp_info *entry = (const struct lwp_info *) a;
684 const struct lwp_info *element = (const struct lwp_info *) b;
686 return entry->ptid.lwp () == element->ptid.lwp ();
689 /* Create the lwp_lwpid_htab hash table. */
692 lwp_lwpid_htab_create (void)
694 lwp_lwpid_htab = htab_create (100, lwp_info_hash, lwp_lwpid_htab_eq, NULL);
697 /* Add LP to the hash table. */
700 lwp_lwpid_htab_add_lwp (struct lwp_info *lp)
704 slot = htab_find_slot (lwp_lwpid_htab, lp, INSERT);
705 gdb_assert (slot != NULL && *slot == NULL);
709 /* Head of doubly-linked list of known LWPs. Sorted by reverse
710 creation order. This order is assumed in some cases. E.g.,
711 reaping status after killing alls lwps of a process: the leader LWP
712 must be reaped last. */
713 struct lwp_info *lwp_list;
715 /* Add LP to sorted-by-reverse-creation-order doubly-linked list. */
718 lwp_list_add (struct lwp_info *lp)
721 if (lwp_list != NULL)
726 /* Remove LP from sorted-by-reverse-creation-order doubly-linked
730 lwp_list_remove (struct lwp_info *lp)
732 /* Remove from sorted-by-creation-order list. */
733 if (lp->next != NULL)
734 lp->next->prev = lp->prev;
735 if (lp->prev != NULL)
736 lp->prev->next = lp->next;
743 /* Original signal mask. */
744 static sigset_t normal_mask;
746 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
747 _initialize_linux_nat. */
748 static sigset_t suspend_mask;
750 /* Signals to block to make that sigsuspend work. */
751 static sigset_t blocked_mask;
753 /* SIGCHLD action. */
754 struct sigaction sigchld_action;
756 /* Block child signals (SIGCHLD and linux threads signals), and store
757 the previous mask in PREV_MASK. */
760 block_child_signals (sigset_t *prev_mask)
762 /* Make sure SIGCHLD is blocked. */
763 if (!sigismember (&blocked_mask, SIGCHLD))
764 sigaddset (&blocked_mask, SIGCHLD);
766 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
769 /* Restore child signals mask, previously returned by
770 block_child_signals. */
773 restore_child_signals_mask (sigset_t *prev_mask)
775 sigprocmask (SIG_SETMASK, prev_mask, NULL);
778 /* Mask of signals to pass directly to the inferior. */
779 static sigset_t pass_mask;
781 /* Update signals to pass to the inferior. */
783 linux_nat_target::pass_signals (int numsigs, unsigned char *pass_signals)
787 sigemptyset (&pass_mask);
789 for (signo = 1; signo < NSIG; signo++)
791 int target_signo = gdb_signal_from_host (signo);
792 if (target_signo < numsigs && pass_signals[target_signo])
793 sigaddset (&pass_mask, signo);
799 /* Prototypes for local functions. */
800 static int stop_wait_callback (struct lwp_info *lp, void *data);
801 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
802 static int check_ptrace_stopped_lwp_gone (struct lwp_info *lp);
806 /* Destroy and free LP. */
809 lwp_free (struct lwp_info *lp)
811 /* Let the arch specific bits release arch_lwp_info. */
812 linux_target->low_delete_thread (lp->arch_private);
817 /* Traversal function for purge_lwp_list. */
820 lwp_lwpid_htab_remove_pid (void **slot, void *info)
822 struct lwp_info *lp = (struct lwp_info *) *slot;
823 int pid = *(int *) info;
825 if (lp->ptid.pid () == pid)
827 htab_clear_slot (lwp_lwpid_htab, slot);
828 lwp_list_remove (lp);
835 /* Remove all LWPs belong to PID from the lwp list. */
838 purge_lwp_list (int pid)
840 htab_traverse_noresize (lwp_lwpid_htab, lwp_lwpid_htab_remove_pid, &pid);
843 /* Add the LWP specified by PTID to the list. PTID is the first LWP
844 in the process. Return a pointer to the structure describing the
847 This differs from add_lwp in that we don't let the arch specific
848 bits know about this new thread. Current clients of this callback
849 take the opportunity to install watchpoints in the new thread, and
850 we shouldn't do that for the first thread. If we're spawning a
851 child ("run"), the thread executes the shell wrapper first, and we
852 shouldn't touch it until it execs the program we want to debug.
853 For "attach", it'd be okay to call the callback, but it's not
854 necessary, because watchpoints can't yet have been inserted into
857 static struct lwp_info *
858 add_initial_lwp (ptid_t ptid)
862 gdb_assert (ptid.lwp_p ());
864 lp = XNEW (struct lwp_info);
866 memset (lp, 0, sizeof (struct lwp_info));
868 lp->last_resume_kind = resume_continue;
869 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
874 /* Add to sorted-by-reverse-creation-order list. */
877 /* Add to keyed-by-pid htab. */
878 lwp_lwpid_htab_add_lwp (lp);
883 /* Add the LWP specified by PID to the list. Return a pointer to the
884 structure describing the new LWP. The LWP should already be
887 static struct lwp_info *
888 add_lwp (ptid_t ptid)
892 lp = add_initial_lwp (ptid);
894 /* Let the arch specific bits know about this new thread. Current
895 clients of this callback take the opportunity to install
896 watchpoints in the new thread. We don't do this for the first
897 thread though. See add_initial_lwp. */
898 linux_target->low_new_thread (lp);
903 /* Remove the LWP specified by PID from the list. */
906 delete_lwp (ptid_t ptid)
910 struct lwp_info dummy;
913 slot = htab_find_slot (lwp_lwpid_htab, &dummy, NO_INSERT);
917 lp = *(struct lwp_info **) slot;
918 gdb_assert (lp != NULL);
920 htab_clear_slot (lwp_lwpid_htab, slot);
922 /* Remove from sorted-by-creation-order list. */
923 lwp_list_remove (lp);
929 /* Return a pointer to the structure describing the LWP corresponding
930 to PID. If no corresponding LWP could be found, return NULL. */
932 static struct lwp_info *
933 find_lwp_pid (ptid_t ptid)
937 struct lwp_info dummy;
944 dummy.ptid = ptid_t (0, lwp, 0);
945 lp = (struct lwp_info *) htab_find (lwp_lwpid_htab, &dummy);
949 /* See nat/linux-nat.h. */
952 iterate_over_lwps (ptid_t filter,
953 iterate_over_lwps_ftype callback,
956 struct lwp_info *lp, *lpnext;
958 for (lp = lwp_list; lp; lp = lpnext)
962 if (lp->ptid.matches (filter))
964 if ((*callback) (lp, data) != 0)
972 /* Update our internal state when changing from one checkpoint to
973 another indicated by NEW_PTID. We can only switch single-threaded
974 applications, so we only create one new LWP, and the previous list
978 linux_nat_switch_fork (ptid_t new_ptid)
982 purge_lwp_list (inferior_ptid.pid ());
984 lp = add_lwp (new_ptid);
987 /* This changes the thread's ptid while preserving the gdb thread
988 num. Also changes the inferior pid, while preserving the
990 thread_change_ptid (inferior_ptid, new_ptid);
992 /* We've just told GDB core that the thread changed target id, but,
993 in fact, it really is a different thread, with different register
995 registers_changed ();
998 /* Handle the exit of a single thread LP. */
1001 exit_lwp (struct lwp_info *lp)
1003 struct thread_info *th = find_thread_ptid (lp->ptid);
1007 if (print_thread_events)
1008 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
1013 delete_lwp (lp->ptid);
1016 /* Wait for the LWP specified by LP, which we have just attached to.
1017 Returns a wait status for that LWP, to cache. */
1020 linux_nat_post_attach_wait (ptid_t ptid, int *signalled)
1022 pid_t new_pid, pid = ptid.lwp ();
1025 if (linux_proc_pid_is_stopped (pid))
1027 if (debug_linux_nat)
1028 fprintf_unfiltered (gdb_stdlog,
1029 "LNPAW: Attaching to a stopped process\n");
1031 /* The process is definitely stopped. It is in a job control
1032 stop, unless the kernel predates the TASK_STOPPED /
1033 TASK_TRACED distinction, in which case it might be in a
1034 ptrace stop. Make sure it is in a ptrace stop; from there we
1035 can kill it, signal it, et cetera.
1037 First make sure there is a pending SIGSTOP. Since we are
1038 already attached, the process can not transition from stopped
1039 to running without a PTRACE_CONT; so we know this signal will
1040 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1041 probably already in the queue (unless this kernel is old
1042 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1043 is not an RT signal, it can only be queued once. */
1044 kill_lwp (pid, SIGSTOP);
1046 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1047 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1048 ptrace (PTRACE_CONT, pid, 0, 0);
1051 /* Make sure the initial process is stopped. The user-level threads
1052 layer might want to poke around in the inferior, and that won't
1053 work if things haven't stabilized yet. */
1054 new_pid = my_waitpid (pid, &status, __WALL);
1055 gdb_assert (pid == new_pid);
1057 if (!WIFSTOPPED (status))
1059 /* The pid we tried to attach has apparently just exited. */
1060 if (debug_linux_nat)
1061 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1062 pid, status_to_str (status));
1066 if (WSTOPSIG (status) != SIGSTOP)
1069 if (debug_linux_nat)
1070 fprintf_unfiltered (gdb_stdlog,
1071 "LNPAW: Received %s after attaching\n",
1072 status_to_str (status));
1079 linux_nat_target::create_inferior (const char *exec_file,
1080 const std::string &allargs,
1081 char **env, int from_tty)
1083 maybe_disable_address_space_randomization restore_personality
1084 (disable_randomization);
1086 /* The fork_child mechanism is synchronous and calls target_wait, so
1087 we have to mask the async mode. */
1089 /* Make sure we report all signals during startup. */
1090 pass_signals (0, NULL);
1092 inf_ptrace_target::create_inferior (exec_file, allargs, env, from_tty);
1095 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1096 already attached. Returns true if a new LWP is found, false
1100 attach_proc_task_lwp_callback (ptid_t ptid)
1102 struct lwp_info *lp;
1104 /* Ignore LWPs we're already attached to. */
1105 lp = find_lwp_pid (ptid);
1108 int lwpid = ptid.lwp ();
1110 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1114 /* Be quiet if we simply raced with the thread exiting.
1115 EPERM is returned if the thread's task still exists, and
1116 is marked as exited or zombie, as well as other
1117 conditions, so in that case, confirm the status in
1118 /proc/PID/status. */
1120 || (err == EPERM && linux_proc_pid_is_gone (lwpid)))
1122 if (debug_linux_nat)
1124 fprintf_unfiltered (gdb_stdlog,
1125 "Cannot attach to lwp %d: "
1126 "thread is gone (%d: %s)\n",
1127 lwpid, err, safe_strerror (err));
1133 = linux_ptrace_attach_fail_reason_string (ptid, err);
1135 warning (_("Cannot attach to lwp %d: %s"),
1136 lwpid, reason.c_str ());
1141 if (debug_linux_nat)
1142 fprintf_unfiltered (gdb_stdlog,
1143 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1144 target_pid_to_str (ptid));
1146 lp = add_lwp (ptid);
1148 /* The next time we wait for this LWP we'll see a SIGSTOP as
1149 PTRACE_ATTACH brings it to a halt. */
1152 /* We need to wait for a stop before being able to make the
1153 next ptrace call on this LWP. */
1154 lp->must_set_ptrace_flags = 1;
1156 /* So that wait collects the SIGSTOP. */
1159 /* Also add the LWP to gdb's thread list, in case a
1160 matching libthread_db is not found (or the process uses
1162 add_thread (lp->ptid);
1163 set_running (lp->ptid, 1);
1164 set_executing (lp->ptid, 1);
1173 linux_nat_target::attach (const char *args, int from_tty)
1175 struct lwp_info *lp;
1179 /* Make sure we report all signals during attach. */
1180 pass_signals (0, NULL);
1184 inf_ptrace_target::attach (args, from_tty);
1186 CATCH (ex, RETURN_MASK_ERROR)
1188 pid_t pid = parse_pid_to_attach (args);
1189 std::string reason = linux_ptrace_attach_fail_reason (pid);
1191 if (!reason.empty ())
1192 throw_error (ex.error, "warning: %s\n%s", reason.c_str (), ex.message);
1194 throw_error (ex.error, "%s", ex.message);
1198 /* The ptrace base target adds the main thread with (pid,0,0)
1199 format. Decorate it with lwp info. */
1200 ptid = ptid_t (inferior_ptid.pid (),
1201 inferior_ptid.pid (),
1203 thread_change_ptid (inferior_ptid, ptid);
1205 /* Add the initial process as the first LWP to the list. */
1206 lp = add_initial_lwp (ptid);
1208 status = linux_nat_post_attach_wait (lp->ptid, &lp->signalled);
1209 if (!WIFSTOPPED (status))
1211 if (WIFEXITED (status))
1213 int exit_code = WEXITSTATUS (status);
1215 target_terminal::ours ();
1216 target_mourn_inferior (inferior_ptid);
1218 error (_("Unable to attach: program exited normally."));
1220 error (_("Unable to attach: program exited with code %d."),
1223 else if (WIFSIGNALED (status))
1225 enum gdb_signal signo;
1227 target_terminal::ours ();
1228 target_mourn_inferior (inferior_ptid);
1230 signo = gdb_signal_from_host (WTERMSIG (status));
1231 error (_("Unable to attach: program terminated with signal "
1233 gdb_signal_to_name (signo),
1234 gdb_signal_to_string (signo));
1237 internal_error (__FILE__, __LINE__,
1238 _("unexpected status %d for PID %ld"),
1239 status, (long) ptid.lwp ());
1244 /* Save the wait status to report later. */
1246 if (debug_linux_nat)
1247 fprintf_unfiltered (gdb_stdlog,
1248 "LNA: waitpid %ld, saving status %s\n",
1249 (long) lp->ptid.pid (), status_to_str (status));
1251 lp->status = status;
1253 /* We must attach to every LWP. If /proc is mounted, use that to
1254 find them now. The inferior may be using raw clone instead of
1255 using pthreads. But even if it is using pthreads, thread_db
1256 walks structures in the inferior's address space to find the list
1257 of threads/LWPs, and those structures may well be corrupted.
1258 Note that once thread_db is loaded, we'll still use it to list
1259 threads and associate pthread info with each LWP. */
1260 linux_proc_attach_tgid_threads (lp->ptid.pid (),
1261 attach_proc_task_lwp_callback);
1263 if (target_can_async_p ())
1267 /* Get pending signal of THREAD as a host signal number, for detaching
1268 purposes. This is the signal the thread last stopped for, which we
1269 need to deliver to the thread when detaching, otherwise, it'd be
1273 get_detach_signal (struct lwp_info *lp)
1275 enum gdb_signal signo = GDB_SIGNAL_0;
1277 /* If we paused threads momentarily, we may have stored pending
1278 events in lp->status or lp->waitstatus (see stop_wait_callback),
1279 and GDB core hasn't seen any signal for those threads.
1280 Otherwise, the last signal reported to the core is found in the
1281 thread object's stop_signal.
1283 There's a corner case that isn't handled here at present. Only
1284 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1285 stop_signal make sense as a real signal to pass to the inferior.
1286 Some catchpoint related events, like
1287 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1288 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1289 those traps are debug API (ptrace in our case) related and
1290 induced; the inferior wouldn't see them if it wasn't being
1291 traced. Hence, we should never pass them to the inferior, even
1292 when set to pass state. Since this corner case isn't handled by
1293 infrun.c when proceeding with a signal, for consistency, neither
1294 do we handle it here (or elsewhere in the file we check for
1295 signal pass state). Normally SIGTRAP isn't set to pass state, so
1296 this is really a corner case. */
1298 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1299 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1300 else if (lp->status)
1301 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1304 struct thread_info *tp = find_thread_ptid (lp->ptid);
1306 if (target_is_non_stop_p () && !tp->executing)
1308 if (tp->suspend.waitstatus_pending_p)
1309 signo = tp->suspend.waitstatus.value.sig;
1311 signo = tp->suspend.stop_signal;
1313 else if (!target_is_non_stop_p ())
1315 struct target_waitstatus last;
1318 get_last_target_status (&last_ptid, &last);
1320 if (lp->ptid.lwp () == last_ptid.lwp ())
1321 signo = tp->suspend.stop_signal;
1325 if (signo == GDB_SIGNAL_0)
1327 if (debug_linux_nat)
1328 fprintf_unfiltered (gdb_stdlog,
1329 "GPT: lwp %s has no pending signal\n",
1330 target_pid_to_str (lp->ptid));
1332 else if (!signal_pass_state (signo))
1334 if (debug_linux_nat)
1335 fprintf_unfiltered (gdb_stdlog,
1336 "GPT: lwp %s had signal %s, "
1337 "but it is in no pass state\n",
1338 target_pid_to_str (lp->ptid),
1339 gdb_signal_to_string (signo));
1343 if (debug_linux_nat)
1344 fprintf_unfiltered (gdb_stdlog,
1345 "GPT: lwp %s has pending signal %s\n",
1346 target_pid_to_str (lp->ptid),
1347 gdb_signal_to_string (signo));
1349 return gdb_signal_to_host (signo);
1355 /* Detach from LP. If SIGNO_P is non-NULL, then it points to the
1356 signal number that should be passed to the LWP when detaching.
1357 Otherwise pass any pending signal the LWP may have, if any. */
1360 detach_one_lwp (struct lwp_info *lp, int *signo_p)
1362 int lwpid = lp->ptid.lwp ();
1365 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1367 if (debug_linux_nat && lp->status)
1368 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1369 strsignal (WSTOPSIG (lp->status)),
1370 target_pid_to_str (lp->ptid));
1372 /* If there is a pending SIGSTOP, get rid of it. */
1375 if (debug_linux_nat)
1376 fprintf_unfiltered (gdb_stdlog,
1377 "DC: Sending SIGCONT to %s\n",
1378 target_pid_to_str (lp->ptid));
1380 kill_lwp (lwpid, SIGCONT);
1384 if (signo_p == NULL)
1386 /* Pass on any pending signal for this LWP. */
1387 signo = get_detach_signal (lp);
1392 /* Preparing to resume may try to write registers, and fail if the
1393 lwp is zombie. If that happens, ignore the error. We'll handle
1394 it below, when detach fails with ESRCH. */
1397 linux_target->low_prepare_to_resume (lp);
1399 CATCH (ex, RETURN_MASK_ERROR)
1401 if (!check_ptrace_stopped_lwp_gone (lp))
1402 throw_exception (ex);
1406 if (ptrace (PTRACE_DETACH, lwpid, 0, signo) < 0)
1408 int save_errno = errno;
1410 /* We know the thread exists, so ESRCH must mean the lwp is
1411 zombie. This can happen if one of the already-detached
1412 threads exits the whole thread group. In that case we're
1413 still attached, and must reap the lwp. */
1414 if (save_errno == ESRCH)
1418 ret = my_waitpid (lwpid, &status, __WALL);
1421 warning (_("Couldn't reap LWP %d while detaching: %s"),
1422 lwpid, strerror (errno));
1424 else if (!WIFEXITED (status) && !WIFSIGNALED (status))
1426 warning (_("Reaping LWP %d while detaching "
1427 "returned unexpected status 0x%x"),
1433 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1434 safe_strerror (save_errno));
1437 else if (debug_linux_nat)
1439 fprintf_unfiltered (gdb_stdlog,
1440 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1441 target_pid_to_str (lp->ptid),
1445 delete_lwp (lp->ptid);
1449 detach_callback (struct lwp_info *lp, void *data)
1451 /* We don't actually detach from the thread group leader just yet.
1452 If the thread group exits, we must reap the zombie clone lwps
1453 before we're able to reap the leader. */
1454 if (lp->ptid.lwp () != lp->ptid.pid ())
1455 detach_one_lwp (lp, NULL);
1460 linux_nat_target::detach (inferior *inf, int from_tty)
1462 struct lwp_info *main_lwp;
1465 /* Don't unregister from the event loop, as there may be other
1466 inferiors running. */
1468 /* Stop all threads before detaching. ptrace requires that the
1469 thread is stopped to sucessfully detach. */
1470 iterate_over_lwps (ptid_t (pid), stop_callback, NULL);
1471 /* ... and wait until all of them have reported back that
1472 they're no longer running. */
1473 iterate_over_lwps (ptid_t (pid), stop_wait_callback, NULL);
1475 iterate_over_lwps (ptid_t (pid), detach_callback, NULL);
1477 /* Only the initial process should be left right now. */
1478 gdb_assert (num_lwps (pid) == 1);
1480 main_lwp = find_lwp_pid (ptid_t (pid));
1482 if (forks_exist_p ())
1484 /* Multi-fork case. The current inferior_ptid is being detached
1485 from, but there are other viable forks to debug. Detach from
1486 the current fork, and context-switch to the first
1488 linux_fork_detach (from_tty);
1492 target_announce_detach (from_tty);
1494 /* Pass on any pending signal for the last LWP. */
1495 int signo = get_detach_signal (main_lwp);
1497 detach_one_lwp (main_lwp, &signo);
1499 detach_success (inf);
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_throw (struct lwp_info *lp, int step,
1508 enum gdb_signal signo)
1512 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1513 We only presently need that if the LWP is stepped though (to
1514 handle the case of stepping a breakpoint instruction). */
1517 struct regcache *regcache = get_thread_regcache (lp->ptid);
1519 lp->stop_pc = regcache_read_pc (regcache);
1524 linux_target->low_prepare_to_resume (lp);
1525 linux_target->low_resume (lp->ptid, step, signo);
1527 /* Successfully resumed. Clear state that no longer makes sense,
1528 and mark the LWP as running. Must not do this before resuming
1529 otherwise if that fails other code will be confused. E.g., we'd
1530 later try to stop the LWP and hang forever waiting for a stop
1531 status. Note that we must not throw after this is cleared,
1532 otherwise handle_zombie_lwp_error would get confused. */
1535 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1536 registers_changed_ptid (lp->ptid);
1539 /* Called when we try to resume a stopped LWP and that errors out. If
1540 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1541 or about to become), discard the error, clear any pending status
1542 the LWP may have, and return true (we'll collect the exit status
1543 soon enough). Otherwise, return false. */
1546 check_ptrace_stopped_lwp_gone (struct lwp_info *lp)
1548 /* If we get an error after resuming the LWP successfully, we'd
1549 confuse !T state for the LWP being gone. */
1550 gdb_assert (lp->stopped);
1552 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1553 because even if ptrace failed with ESRCH, the tracee may be "not
1554 yet fully dead", but already refusing ptrace requests. In that
1555 case the tracee has 'R (Running)' state for a little bit
1556 (observed in Linux 3.18). See also the note on ESRCH in the
1557 ptrace(2) man page. Instead, check whether the LWP has any state
1558 other than ptrace-stopped. */
1560 /* Don't assume anything if /proc/PID/status can't be read. */
1561 if (linux_proc_pid_is_trace_stopped_nowarn (lp->ptid.lwp ()) == 0)
1563 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1565 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
1571 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1572 disappears while we try to resume it. */
1575 linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1579 linux_resume_one_lwp_throw (lp, step, signo);
1581 CATCH (ex, RETURN_MASK_ERROR)
1583 if (!check_ptrace_stopped_lwp_gone (lp))
1584 throw_exception (ex);
1592 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1596 struct inferior *inf = find_inferior_ptid (lp->ptid);
1598 if (inf->vfork_child != NULL)
1600 if (debug_linux_nat)
1601 fprintf_unfiltered (gdb_stdlog,
1602 "RC: Not resuming %s (vfork parent)\n",
1603 target_pid_to_str (lp->ptid));
1605 else if (!lwp_status_pending_p (lp))
1607 if (debug_linux_nat)
1608 fprintf_unfiltered (gdb_stdlog,
1609 "RC: Resuming sibling %s, %s, %s\n",
1610 target_pid_to_str (lp->ptid),
1611 (signo != GDB_SIGNAL_0
1612 ? strsignal (gdb_signal_to_host (signo))
1614 step ? "step" : "resume");
1616 linux_resume_one_lwp (lp, step, signo);
1620 if (debug_linux_nat)
1621 fprintf_unfiltered (gdb_stdlog,
1622 "RC: Not resuming sibling %s (has pending)\n",
1623 target_pid_to_str (lp->ptid));
1628 if (debug_linux_nat)
1629 fprintf_unfiltered (gdb_stdlog,
1630 "RC: Not resuming sibling %s (not stopped)\n",
1631 target_pid_to_str (lp->ptid));
1635 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1636 Resume LWP with the last stop signal, if it is in pass state. */
1639 linux_nat_resume_callback (struct lwp_info *lp, void *except)
1641 enum gdb_signal signo = GDB_SIGNAL_0;
1648 struct thread_info *thread;
1650 thread = find_thread_ptid (lp->ptid);
1653 signo = thread->suspend.stop_signal;
1654 thread->suspend.stop_signal = GDB_SIGNAL_0;
1658 resume_lwp (lp, 0, signo);
1663 resume_clear_callback (struct lwp_info *lp, void *data)
1666 lp->last_resume_kind = resume_stop;
1671 resume_set_callback (struct lwp_info *lp, void *data)
1674 lp->last_resume_kind = resume_continue;
1679 linux_nat_target::resume (ptid_t ptid, int step, enum gdb_signal signo)
1681 struct lwp_info *lp;
1684 if (debug_linux_nat)
1685 fprintf_unfiltered (gdb_stdlog,
1686 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1687 step ? "step" : "resume",
1688 target_pid_to_str (ptid),
1689 (signo != GDB_SIGNAL_0
1690 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1691 target_pid_to_str (inferior_ptid));
1693 /* A specific PTID means `step only this process id'. */
1694 resume_many = (minus_one_ptid == ptid
1697 /* Mark the lwps we're resuming as resumed. */
1698 iterate_over_lwps (ptid, resume_set_callback, NULL);
1700 /* See if it's the current inferior that should be handled
1703 lp = find_lwp_pid (inferior_ptid);
1705 lp = find_lwp_pid (ptid);
1706 gdb_assert (lp != NULL);
1708 /* Remember if we're stepping. */
1709 lp->last_resume_kind = step ? resume_step : resume_continue;
1711 /* If we have a pending wait status for this thread, there is no
1712 point in resuming the process. But first make sure that
1713 linux_nat_wait won't preemptively handle the event - we
1714 should never take this short-circuit if we are going to
1715 leave LP running, since we have skipped resuming all the
1716 other threads. This bit of code needs to be synchronized
1717 with linux_nat_wait. */
1719 if (lp->status && WIFSTOPPED (lp->status))
1722 && WSTOPSIG (lp->status)
1723 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1725 if (debug_linux_nat)
1726 fprintf_unfiltered (gdb_stdlog,
1727 "LLR: Not short circuiting for ignored "
1728 "status 0x%x\n", lp->status);
1730 /* FIXME: What should we do if we are supposed to continue
1731 this thread with a signal? */
1732 gdb_assert (signo == GDB_SIGNAL_0);
1733 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1738 if (lwp_status_pending_p (lp))
1740 /* FIXME: What should we do if we are supposed to continue
1741 this thread with a signal? */
1742 gdb_assert (signo == GDB_SIGNAL_0);
1744 if (debug_linux_nat)
1745 fprintf_unfiltered (gdb_stdlog,
1746 "LLR: Short circuiting for status 0x%x\n",
1749 if (target_can_async_p ())
1752 /* Tell the event loop we have something to process. */
1759 iterate_over_lwps (ptid, linux_nat_resume_callback, lp);
1761 if (debug_linux_nat)
1762 fprintf_unfiltered (gdb_stdlog,
1763 "LLR: %s %s, %s (resume event thread)\n",
1764 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1765 target_pid_to_str (lp->ptid),
1766 (signo != GDB_SIGNAL_0
1767 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1769 linux_resume_one_lwp (lp, step, signo);
1771 if (target_can_async_p ())
1775 /* Send a signal to an LWP. */
1778 kill_lwp (int lwpid, int signo)
1783 ret = syscall (__NR_tkill, lwpid, signo);
1784 if (errno == ENOSYS)
1786 /* If tkill fails, then we are not using nptl threads, a
1787 configuration we no longer support. */
1788 perror_with_name (("tkill"));
1793 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1794 event, check if the core is interested in it: if not, ignore the
1795 event, and keep waiting; otherwise, we need to toggle the LWP's
1796 syscall entry/exit status, since the ptrace event itself doesn't
1797 indicate it, and report the trap to higher layers. */
1800 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1802 struct target_waitstatus *ourstatus = &lp->waitstatus;
1803 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1804 thread_info *thread = find_thread_ptid (lp->ptid);
1805 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, thread);
1809 /* If we're stopping threads, there's a SIGSTOP pending, which
1810 makes it so that the LWP reports an immediate syscall return,
1811 followed by the SIGSTOP. Skip seeing that "return" using
1812 PTRACE_CONT directly, and let stop_wait_callback collect the
1813 SIGSTOP. Later when the thread is resumed, a new syscall
1814 entry event. If we didn't do this (and returned 0), we'd
1815 leave a syscall entry pending, and our caller, by using
1816 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1817 itself. Later, when the user re-resumes this LWP, we'd see
1818 another syscall entry event and we'd mistake it for a return.
1820 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1821 (leaving immediately with LWP->signalled set, without issuing
1822 a PTRACE_CONT), it would still be problematic to leave this
1823 syscall enter pending, as later when the thread is resumed,
1824 it would then see the same syscall exit mentioned above,
1825 followed by the delayed SIGSTOP, while the syscall didn't
1826 actually get to execute. It seems it would be even more
1827 confusing to the user. */
1829 if (debug_linux_nat)
1830 fprintf_unfiltered (gdb_stdlog,
1831 "LHST: ignoring syscall %d "
1832 "for LWP %ld (stopping threads), "
1833 "resuming with PTRACE_CONT for SIGSTOP\n",
1837 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1838 ptrace (PTRACE_CONT, lp->ptid.lwp (), 0, 0);
1843 /* Always update the entry/return state, even if this particular
1844 syscall isn't interesting to the core now. In async mode,
1845 the user could install a new catchpoint for this syscall
1846 between syscall enter/return, and we'll need to know to
1847 report a syscall return if that happens. */
1848 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1849 ? TARGET_WAITKIND_SYSCALL_RETURN
1850 : TARGET_WAITKIND_SYSCALL_ENTRY);
1852 if (catch_syscall_enabled ())
1854 if (catching_syscall_number (syscall_number))
1856 /* Alright, an event to report. */
1857 ourstatus->kind = lp->syscall_state;
1858 ourstatus->value.syscall_number = syscall_number;
1860 if (debug_linux_nat)
1861 fprintf_unfiltered (gdb_stdlog,
1862 "LHST: stopping for %s of syscall %d"
1865 == TARGET_WAITKIND_SYSCALL_ENTRY
1866 ? "entry" : "return",
1872 if (debug_linux_nat)
1873 fprintf_unfiltered (gdb_stdlog,
1874 "LHST: ignoring %s of syscall %d "
1876 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1877 ? "entry" : "return",
1883 /* If we had been syscall tracing, and hence used PT_SYSCALL
1884 before on this LWP, it could happen that the user removes all
1885 syscall catchpoints before we get to process this event.
1886 There are two noteworthy issues here:
1888 - When stopped at a syscall entry event, resuming with
1889 PT_STEP still resumes executing the syscall and reports a
1892 - Only PT_SYSCALL catches syscall enters. If we last
1893 single-stepped this thread, then this event can't be a
1894 syscall enter. If we last single-stepped this thread, this
1895 has to be a syscall exit.
1897 The points above mean that the next resume, be it PT_STEP or
1898 PT_CONTINUE, can not trigger a syscall trace event. */
1899 if (debug_linux_nat)
1900 fprintf_unfiltered (gdb_stdlog,
1901 "LHST: caught syscall event "
1902 "with no syscall catchpoints."
1903 " %d for LWP %ld, ignoring\n",
1906 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1909 /* The core isn't interested in this event. For efficiency, avoid
1910 stopping all threads only to have the core resume them all again.
1911 Since we're not stopping threads, if we're still syscall tracing
1912 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1913 subsequent syscall. Simply resume using the inf-ptrace layer,
1914 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1916 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
1920 /* Handle a GNU/Linux extended wait response. If we see a clone
1921 event, we need to add the new LWP to our list (and not report the
1922 trap to higher layers). This function returns non-zero if the
1923 event should be ignored and we should wait again. If STOPPING is
1924 true, the new LWP remains stopped, otherwise it is continued. */
1927 linux_handle_extended_wait (struct lwp_info *lp, int status)
1929 int pid = lp->ptid.lwp ();
1930 struct target_waitstatus *ourstatus = &lp->waitstatus;
1931 int event = linux_ptrace_get_extended_event (status);
1933 /* All extended events we currently use are mid-syscall. Only
1934 PTRACE_EVENT_STOP is delivered more like a signal-stop, but
1935 you have to be using PTRACE_SEIZE to get that. */
1936 lp->syscall_state = TARGET_WAITKIND_SYSCALL_ENTRY;
1938 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1939 || event == PTRACE_EVENT_CLONE)
1941 unsigned long new_pid;
1944 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
1946 /* If we haven't already seen the new PID stop, wait for it now. */
1947 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
1949 /* The new child has a pending SIGSTOP. We can't affect it until it
1950 hits the SIGSTOP, but we're already attached. */
1951 ret = my_waitpid (new_pid, &status, __WALL);
1953 perror_with_name (_("waiting for new child"));
1954 else if (ret != new_pid)
1955 internal_error (__FILE__, __LINE__,
1956 _("wait returned unexpected PID %d"), ret);
1957 else if (!WIFSTOPPED (status))
1958 internal_error (__FILE__, __LINE__,
1959 _("wait returned unexpected status 0x%x"), status);
1962 ourstatus->value.related_pid = ptid_t (new_pid, new_pid, 0);
1964 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
1966 /* The arch-specific native code may need to know about new
1967 forks even if those end up never mapped to an
1969 linux_target->low_new_fork (lp, new_pid);
1972 if (event == PTRACE_EVENT_FORK
1973 && linux_fork_checkpointing_p (lp->ptid.pid ()))
1975 /* Handle checkpointing by linux-fork.c here as a special
1976 case. We don't want the follow-fork-mode or 'catch fork'
1977 to interfere with this. */
1979 /* This won't actually modify the breakpoint list, but will
1980 physically remove the breakpoints from the child. */
1981 detach_breakpoints (ptid_t (new_pid, new_pid, 0));
1983 /* Retain child fork in ptrace (stopped) state. */
1984 if (!find_fork_pid (new_pid))
1987 /* Report as spurious, so that infrun doesn't want to follow
1988 this fork. We're actually doing an infcall in
1990 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
1992 /* Report the stop to the core. */
1996 if (event == PTRACE_EVENT_FORK)
1997 ourstatus->kind = TARGET_WAITKIND_FORKED;
1998 else if (event == PTRACE_EVENT_VFORK)
1999 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2000 else if (event == PTRACE_EVENT_CLONE)
2002 struct lwp_info *new_lp;
2004 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2006 if (debug_linux_nat)
2007 fprintf_unfiltered (gdb_stdlog,
2008 "LHEW: Got clone event "
2009 "from LWP %d, new child is LWP %ld\n",
2012 new_lp = add_lwp (ptid_t (lp->ptid.pid (), new_pid, 0));
2013 new_lp->stopped = 1;
2014 new_lp->resumed = 1;
2016 /* If the thread_db layer is active, let it record the user
2017 level thread id and status, and add the thread to GDB's
2019 if (!thread_db_notice_clone (lp->ptid, new_lp->ptid))
2021 /* The process is not using thread_db. Add the LWP to
2023 target_post_attach (new_lp->ptid.lwp ());
2024 add_thread (new_lp->ptid);
2027 /* Even if we're stopping the thread for some reason
2028 internal to this module, from the perspective of infrun
2029 and the user/frontend, this new thread is running until
2030 it next reports a stop. */
2031 set_running (new_lp->ptid, 1);
2032 set_executing (new_lp->ptid, 1);
2034 if (WSTOPSIG (status) != SIGSTOP)
2036 /* This can happen if someone starts sending signals to
2037 the new thread before it gets a chance to run, which
2038 have a lower number than SIGSTOP (e.g. SIGUSR1).
2039 This is an unlikely case, and harder to handle for
2040 fork / vfork than for clone, so we do not try - but
2041 we handle it for clone events here. */
2043 new_lp->signalled = 1;
2045 /* We created NEW_LP so it cannot yet contain STATUS. */
2046 gdb_assert (new_lp->status == 0);
2048 /* Save the wait status to report later. */
2049 if (debug_linux_nat)
2050 fprintf_unfiltered (gdb_stdlog,
2051 "LHEW: waitpid of new LWP %ld, "
2052 "saving status %s\n",
2053 (long) new_lp->ptid.lwp (),
2054 status_to_str (status));
2055 new_lp->status = status;
2057 else if (report_thread_events)
2059 new_lp->waitstatus.kind = TARGET_WAITKIND_THREAD_CREATED;
2060 new_lp->status = status;
2069 if (event == PTRACE_EVENT_EXEC)
2071 if (debug_linux_nat)
2072 fprintf_unfiltered (gdb_stdlog,
2073 "LHEW: Got exec event from LWP %ld\n",
2076 ourstatus->kind = TARGET_WAITKIND_EXECD;
2077 ourstatus->value.execd_pathname
2078 = xstrdup (linux_proc_pid_to_exec_file (pid));
2080 /* The thread that execed must have been resumed, but, when a
2081 thread execs, it changes its tid to the tgid, and the old
2082 tgid thread might have not been resumed. */
2087 if (event == PTRACE_EVENT_VFORK_DONE)
2089 if (current_inferior ()->waiting_for_vfork_done)
2091 if (debug_linux_nat)
2092 fprintf_unfiltered (gdb_stdlog,
2093 "LHEW: Got expected PTRACE_EVENT_"
2094 "VFORK_DONE from LWP %ld: stopping\n",
2097 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2101 if (debug_linux_nat)
2102 fprintf_unfiltered (gdb_stdlog,
2103 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2104 "from LWP %ld: ignoring\n",
2109 internal_error (__FILE__, __LINE__,
2110 _("unknown ptrace event %d"), event);
2113 /* Suspend waiting for a signal. We're mostly interested in
2119 if (debug_linux_nat)
2120 fprintf_unfiltered (gdb_stdlog, "linux-nat: about to sigsuspend\n");
2121 sigsuspend (&suspend_mask);
2123 /* If the quit flag is set, it means that the user pressed Ctrl-C
2124 and we're debugging a process that is running on a separate
2125 terminal, so we must forward the Ctrl-C to the inferior. (If the
2126 inferior is sharing GDB's terminal, then the Ctrl-C reaches the
2127 inferior directly.) We must do this here because functions that
2128 need to block waiting for a signal loop forever until there's an
2129 event to report before returning back to the event loop. */
2130 if (!target_terminal::is_ours ())
2132 if (check_quit_flag ())
2133 target_pass_ctrlc ();
2137 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2141 wait_lwp (struct lwp_info *lp)
2145 int thread_dead = 0;
2148 gdb_assert (!lp->stopped);
2149 gdb_assert (lp->status == 0);
2151 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2152 block_child_signals (&prev_mask);
2156 pid = my_waitpid (lp->ptid.lwp (), &status, __WALL | WNOHANG);
2157 if (pid == -1 && errno == ECHILD)
2159 /* The thread has previously exited. We need to delete it
2160 now because if this was a non-leader thread execing, we
2161 won't get an exit event. See comments on exec events at
2162 the top of the file. */
2164 if (debug_linux_nat)
2165 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2166 target_pid_to_str (lp->ptid));
2171 /* Bugs 10970, 12702.
2172 Thread group leader may have exited in which case we'll lock up in
2173 waitpid if there are other threads, even if they are all zombies too.
2174 Basically, we're not supposed to use waitpid this way.
2175 tkill(pid,0) cannot be used here as it gets ESRCH for both
2176 for zombie and running processes.
2178 As a workaround, check if we're waiting for the thread group leader and
2179 if it's a zombie, and avoid calling waitpid if it is.
2181 This is racy, what if the tgl becomes a zombie right after we check?
2182 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2183 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2185 if (lp->ptid.pid () == lp->ptid.lwp ()
2186 && linux_proc_pid_is_zombie (lp->ptid.lwp ()))
2189 if (debug_linux_nat)
2190 fprintf_unfiltered (gdb_stdlog,
2191 "WL: Thread group leader %s vanished.\n",
2192 target_pid_to_str (lp->ptid));
2196 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2197 get invoked despite our caller had them intentionally blocked by
2198 block_child_signals. This is sensitive only to the loop of
2199 linux_nat_wait_1 and there if we get called my_waitpid gets called
2200 again before it gets to sigsuspend so we can safely let the handlers
2201 get executed here. */
2205 restore_child_signals_mask (&prev_mask);
2209 gdb_assert (pid == lp->ptid.lwp ());
2211 if (debug_linux_nat)
2213 fprintf_unfiltered (gdb_stdlog,
2214 "WL: waitpid %s received %s\n",
2215 target_pid_to_str (lp->ptid),
2216 status_to_str (status));
2219 /* Check if the thread has exited. */
2220 if (WIFEXITED (status) || WIFSIGNALED (status))
2222 if (report_thread_events
2223 || lp->ptid.pid () == lp->ptid.lwp ())
2225 if (debug_linux_nat)
2226 fprintf_unfiltered (gdb_stdlog, "WL: LWP %d exited.\n",
2229 /* If this is the leader exiting, it means the whole
2230 process is gone. Store the status to report to the
2231 core. Store it in lp->waitstatus, because lp->status
2232 would be ambiguous (W_EXITCODE(0,0) == 0). */
2233 store_waitstatus (&lp->waitstatus, status);
2238 if (debug_linux_nat)
2239 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2240 target_pid_to_str (lp->ptid));
2250 gdb_assert (WIFSTOPPED (status));
2253 if (lp->must_set_ptrace_flags)
2255 struct inferior *inf = find_inferior_pid (lp->ptid.pid ());
2256 int options = linux_nat_ptrace_options (inf->attach_flag);
2258 linux_enable_event_reporting (lp->ptid.lwp (), options);
2259 lp->must_set_ptrace_flags = 0;
2262 /* Handle GNU/Linux's syscall SIGTRAPs. */
2263 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2265 /* No longer need the sysgood bit. The ptrace event ends up
2266 recorded in lp->waitstatus if we care for it. We can carry
2267 on handling the event like a regular SIGTRAP from here
2269 status = W_STOPCODE (SIGTRAP);
2270 if (linux_handle_syscall_trap (lp, 1))
2271 return wait_lwp (lp);
2275 /* Almost all other ptrace-stops are known to be outside of system
2276 calls, with further exceptions in linux_handle_extended_wait. */
2277 lp->syscall_state = TARGET_WAITKIND_IGNORE;
2280 /* Handle GNU/Linux's extended waitstatus for trace events. */
2281 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
2282 && linux_is_extended_waitstatus (status))
2284 if (debug_linux_nat)
2285 fprintf_unfiltered (gdb_stdlog,
2286 "WL: Handling extended status 0x%06x\n",
2288 linux_handle_extended_wait (lp, status);
2295 /* Send a SIGSTOP to LP. */
2298 stop_callback (struct lwp_info *lp, void *data)
2300 if (!lp->stopped && !lp->signalled)
2304 if (debug_linux_nat)
2306 fprintf_unfiltered (gdb_stdlog,
2307 "SC: kill %s **<SIGSTOP>**\n",
2308 target_pid_to_str (lp->ptid));
2311 ret = kill_lwp (lp->ptid.lwp (), SIGSTOP);
2312 if (debug_linux_nat)
2314 fprintf_unfiltered (gdb_stdlog,
2315 "SC: lwp kill %d %s\n",
2317 errno ? safe_strerror (errno) : "ERRNO-OK");
2321 gdb_assert (lp->status == 0);
2327 /* Request a stop on LWP. */
2330 linux_stop_lwp (struct lwp_info *lwp)
2332 stop_callback (lwp, NULL);
2335 /* See linux-nat.h */
2338 linux_stop_and_wait_all_lwps (void)
2340 /* Stop all LWP's ... */
2341 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
2343 /* ... and wait until all of them have reported back that
2344 they're no longer running. */
2345 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
2348 /* See linux-nat.h */
2351 linux_unstop_all_lwps (void)
2353 iterate_over_lwps (minus_one_ptid,
2354 resume_stopped_resumed_lwps, &minus_one_ptid);
2357 /* Return non-zero if LWP PID has a pending SIGINT. */
2360 linux_nat_has_pending_sigint (int pid)
2362 sigset_t pending, blocked, ignored;
2364 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2366 if (sigismember (&pending, SIGINT)
2367 && !sigismember (&ignored, SIGINT))
2373 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2376 set_ignore_sigint (struct lwp_info *lp, void *data)
2378 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2379 flag to consume the next one. */
2380 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2381 && WSTOPSIG (lp->status) == SIGINT)
2384 lp->ignore_sigint = 1;
2389 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2390 This function is called after we know the LWP has stopped; if the LWP
2391 stopped before the expected SIGINT was delivered, then it will never have
2392 arrived. Also, if the signal was delivered to a shared queue and consumed
2393 by a different thread, it will never be delivered to this LWP. */
2396 maybe_clear_ignore_sigint (struct lwp_info *lp)
2398 if (!lp->ignore_sigint)
2401 if (!linux_nat_has_pending_sigint (lp->ptid.lwp ()))
2403 if (debug_linux_nat)
2404 fprintf_unfiltered (gdb_stdlog,
2405 "MCIS: Clearing bogus flag for %s\n",
2406 target_pid_to_str (lp->ptid));
2407 lp->ignore_sigint = 0;
2411 /* Fetch the possible triggered data watchpoint info and store it in
2414 On some archs, like x86, that use debug registers to set
2415 watchpoints, it's possible that the way to know which watched
2416 address trapped, is to check the register that is used to select
2417 which address to watch. Problem is, between setting the watchpoint
2418 and reading back which data address trapped, the user may change
2419 the set of watchpoints, and, as a consequence, GDB changes the
2420 debug registers in the inferior. To avoid reading back a stale
2421 stopped-data-address when that happens, we cache in LP the fact
2422 that a watchpoint trapped, and the corresponding data address, as
2423 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2424 registers meanwhile, we have the cached data we can rely on. */
2427 check_stopped_by_watchpoint (struct lwp_info *lp)
2429 scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
2430 inferior_ptid = lp->ptid;
2432 if (linux_target->low_stopped_by_watchpoint ())
2434 lp->stop_reason = TARGET_STOPPED_BY_WATCHPOINT;
2435 lp->stopped_data_address_p
2436 = linux_target->low_stopped_data_address (&lp->stopped_data_address);
2439 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2442 /* Returns true if the LWP had stopped for a watchpoint. */
2445 linux_nat_target::stopped_by_watchpoint ()
2447 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2449 gdb_assert (lp != NULL);
2451 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2455 linux_nat_target::stopped_data_address (CORE_ADDR *addr_p)
2457 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2459 gdb_assert (lp != NULL);
2461 *addr_p = lp->stopped_data_address;
2463 return lp->stopped_data_address_p;
2466 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2469 linux_nat_target::low_status_is_event (int status)
2471 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2474 /* Wait until LP is stopped. */
2477 stop_wait_callback (struct lwp_info *lp, void *data)
2479 struct inferior *inf = find_inferior_ptid (lp->ptid);
2481 /* If this is a vfork parent, bail out, it is not going to report
2482 any SIGSTOP until the vfork is done with. */
2483 if (inf->vfork_child != NULL)
2490 status = wait_lwp (lp);
2494 if (lp->ignore_sigint && WIFSTOPPED (status)
2495 && WSTOPSIG (status) == SIGINT)
2497 lp->ignore_sigint = 0;
2500 ptrace (PTRACE_CONT, lp->ptid.lwp (), 0, 0);
2502 if (debug_linux_nat)
2503 fprintf_unfiltered (gdb_stdlog,
2504 "PTRACE_CONT %s, 0, 0 (%s) "
2505 "(discarding SIGINT)\n",
2506 target_pid_to_str (lp->ptid),
2507 errno ? safe_strerror (errno) : "OK");
2509 return stop_wait_callback (lp, NULL);
2512 maybe_clear_ignore_sigint (lp);
2514 if (WSTOPSIG (status) != SIGSTOP)
2516 /* The thread was stopped with a signal other than SIGSTOP. */
2518 if (debug_linux_nat)
2519 fprintf_unfiltered (gdb_stdlog,
2520 "SWC: Pending event %s in %s\n",
2521 status_to_str ((int) status),
2522 target_pid_to_str (lp->ptid));
2524 /* Save the sigtrap event. */
2525 lp->status = status;
2526 gdb_assert (lp->signalled);
2527 save_stop_reason (lp);
2531 /* We caught the SIGSTOP that we intended to catch. */
2533 if (debug_linux_nat)
2534 fprintf_unfiltered (gdb_stdlog,
2535 "SWC: Expected SIGSTOP caught for %s.\n",
2536 target_pid_to_str (lp->ptid));
2540 /* If we are waiting for this stop so we can report the thread
2541 stopped then we need to record this status. Otherwise, we can
2542 now discard this stop event. */
2543 if (lp->last_resume_kind == resume_stop)
2545 lp->status = status;
2546 save_stop_reason (lp);
2554 /* Return non-zero if LP has a wait status pending. Discard the
2555 pending event and resume the LWP if the event that originally
2556 caused the stop became uninteresting. */
2559 status_callback (struct lwp_info *lp, void *data)
2561 /* Only report a pending wait status if we pretend that this has
2562 indeed been resumed. */
2566 if (!lwp_status_pending_p (lp))
2569 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
2570 || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2572 struct regcache *regcache = get_thread_regcache (lp->ptid);
2576 pc = regcache_read_pc (regcache);
2578 if (pc != lp->stop_pc)
2580 if (debug_linux_nat)
2581 fprintf_unfiltered (gdb_stdlog,
2582 "SC: PC of %s changed. was=%s, now=%s\n",
2583 target_pid_to_str (lp->ptid),
2584 paddress (target_gdbarch (), lp->stop_pc),
2585 paddress (target_gdbarch (), pc));
2589 #if !USE_SIGTRAP_SIGINFO
2590 else if (!breakpoint_inserted_here_p (regcache->aspace (), pc))
2592 if (debug_linux_nat)
2593 fprintf_unfiltered (gdb_stdlog,
2594 "SC: previous breakpoint of %s, at %s gone\n",
2595 target_pid_to_str (lp->ptid),
2596 paddress (target_gdbarch (), lp->stop_pc));
2604 if (debug_linux_nat)
2605 fprintf_unfiltered (gdb_stdlog,
2606 "SC: pending event of %s cancelled.\n",
2607 target_pid_to_str (lp->ptid));
2610 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
2618 /* Count the LWP's that have had events. */
2621 count_events_callback (struct lwp_info *lp, void *data)
2623 int *count = (int *) data;
2625 gdb_assert (count != NULL);
2627 /* Select only resumed LWPs that have an event pending. */
2628 if (lp->resumed && lwp_status_pending_p (lp))
2634 /* Select the LWP (if any) that is currently being single-stepped. */
2637 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2639 if (lp->last_resume_kind == resume_step
2646 /* Returns true if LP has a status pending. */
2649 lwp_status_pending_p (struct lwp_info *lp)
2651 /* We check for lp->waitstatus in addition to lp->status, because we
2652 can have pending process exits recorded in lp->status and
2653 W_EXITCODE(0,0) happens to be 0. */
2654 return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE;
2657 /* Select the Nth LWP that has had an event. */
2660 select_event_lwp_callback (struct lwp_info *lp, void *data)
2662 int *selector = (int *) data;
2664 gdb_assert (selector != NULL);
2666 /* Select only resumed LWPs that have an event pending. */
2667 if (lp->resumed && lwp_status_pending_p (lp))
2668 if ((*selector)-- == 0)
2674 /* Called when the LWP stopped for a signal/trap. If it stopped for a
2675 trap check what caused it (breakpoint, watchpoint, trace, etc.),
2676 and save the result in the LWP's stop_reason field. If it stopped
2677 for a breakpoint, decrement the PC if necessary on the lwp's
2681 save_stop_reason (struct lwp_info *lp)
2683 struct regcache *regcache;
2684 struct gdbarch *gdbarch;
2687 #if USE_SIGTRAP_SIGINFO
2691 gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
2692 gdb_assert (lp->status != 0);
2694 if (!linux_target->low_status_is_event (lp->status))
2697 regcache = get_thread_regcache (lp->ptid);
2698 gdbarch = regcache->arch ();
2700 pc = regcache_read_pc (regcache);
2701 sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch);
2703 #if USE_SIGTRAP_SIGINFO
2704 if (linux_nat_get_siginfo (lp->ptid, &siginfo))
2706 if (siginfo.si_signo == SIGTRAP)
2708 if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code)
2709 && GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
2711 /* The si_code is ambiguous on this arch -- check debug
2713 if (!check_stopped_by_watchpoint (lp))
2714 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2716 else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code))
2718 /* If we determine the LWP stopped for a SW breakpoint,
2719 trust it. Particularly don't check watchpoint
2720 registers, because at least on s390, we'd find
2721 stopped-by-watchpoint as long as there's a watchpoint
2723 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2725 else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
2727 /* This can indicate either a hardware breakpoint or
2728 hardware watchpoint. Check debug registers. */
2729 if (!check_stopped_by_watchpoint (lp))
2730 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2732 else if (siginfo.si_code == TRAP_TRACE)
2734 if (debug_linux_nat)
2735 fprintf_unfiltered (gdb_stdlog,
2736 "CSBB: %s stopped by trace\n",
2737 target_pid_to_str (lp->ptid));
2739 /* We may have single stepped an instruction that
2740 triggered a watchpoint. In that case, on some
2741 architectures (such as x86), instead of TRAP_HWBKPT,
2742 si_code indicates TRAP_TRACE, and we need to check
2743 the debug registers separately. */
2744 check_stopped_by_watchpoint (lp);
2749 if ((!lp->step || lp->stop_pc == sw_bp_pc)
2750 && software_breakpoint_inserted_here_p (regcache->aspace (),
2753 /* The LWP was either continued, or stepped a software
2754 breakpoint instruction. */
2755 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2758 if (hardware_breakpoint_inserted_here_p (regcache->aspace (), pc))
2759 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2761 if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON)
2762 check_stopped_by_watchpoint (lp);
2765 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT)
2767 if (debug_linux_nat)
2768 fprintf_unfiltered (gdb_stdlog,
2769 "CSBB: %s stopped by software breakpoint\n",
2770 target_pid_to_str (lp->ptid));
2772 /* Back up the PC if necessary. */
2774 regcache_write_pc (regcache, sw_bp_pc);
2776 /* Update this so we record the correct stop PC below. */
2779 else if (lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2781 if (debug_linux_nat)
2782 fprintf_unfiltered (gdb_stdlog,
2783 "CSBB: %s stopped by hardware breakpoint\n",
2784 target_pid_to_str (lp->ptid));
2786 else if (lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT)
2788 if (debug_linux_nat)
2789 fprintf_unfiltered (gdb_stdlog,
2790 "CSBB: %s stopped by hardware watchpoint\n",
2791 target_pid_to_str (lp->ptid));
2798 /* Returns true if the LWP had stopped for a software breakpoint. */
2801 linux_nat_target::stopped_by_sw_breakpoint ()
2803 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2805 gdb_assert (lp != NULL);
2807 return lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT;
2810 /* Implement the supports_stopped_by_sw_breakpoint method. */
2813 linux_nat_target::supports_stopped_by_sw_breakpoint ()
2815 return USE_SIGTRAP_SIGINFO;
2818 /* Returns true if the LWP had stopped for a hardware
2819 breakpoint/watchpoint. */
2822 linux_nat_target::stopped_by_hw_breakpoint ()
2824 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2826 gdb_assert (lp != NULL);
2828 return lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT;
2831 /* Implement the supports_stopped_by_hw_breakpoint method. */
2834 linux_nat_target::supports_stopped_by_hw_breakpoint ()
2836 return USE_SIGTRAP_SIGINFO;
2839 /* Select one LWP out of those that have events pending. */
2842 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2845 int random_selector;
2846 struct lwp_info *event_lp = NULL;
2848 /* Record the wait status for the original LWP. */
2849 (*orig_lp)->status = *status;
2851 /* In all-stop, give preference to the LWP that is being
2852 single-stepped. There will be at most one, and it will be the
2853 LWP that the core is most interested in. If we didn't do this,
2854 then we'd have to handle pending step SIGTRAPs somehow in case
2855 the core later continues the previously-stepped thread, as
2856 otherwise we'd report the pending SIGTRAP then, and the core, not
2857 having stepped the thread, wouldn't understand what the trap was
2858 for, and therefore would report it to the user as a random
2860 if (!target_is_non_stop_p ())
2862 event_lp = iterate_over_lwps (filter,
2863 select_singlestep_lwp_callback, NULL);
2864 if (event_lp != NULL)
2866 if (debug_linux_nat)
2867 fprintf_unfiltered (gdb_stdlog,
2868 "SEL: Select single-step %s\n",
2869 target_pid_to_str (event_lp->ptid));
2873 if (event_lp == NULL)
2875 /* Pick one at random, out of those which have had events. */
2877 /* First see how many events we have. */
2878 iterate_over_lwps (filter, count_events_callback, &num_events);
2879 gdb_assert (num_events > 0);
2881 /* Now randomly pick a LWP out of those that have had
2883 random_selector = (int)
2884 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2886 if (debug_linux_nat && num_events > 1)
2887 fprintf_unfiltered (gdb_stdlog,
2888 "SEL: Found %d events, selecting #%d\n",
2889 num_events, random_selector);
2891 event_lp = iterate_over_lwps (filter,
2892 select_event_lwp_callback,
2896 if (event_lp != NULL)
2898 /* Switch the event LWP. */
2899 *orig_lp = event_lp;
2900 *status = event_lp->status;
2903 /* Flush the wait status for the event LWP. */
2904 (*orig_lp)->status = 0;
2907 /* Return non-zero if LP has been resumed. */
2910 resumed_callback (struct lwp_info *lp, void *data)
2915 /* Check if we should go on and pass this event to common code.
2916 Return the affected lwp if we are, or NULL otherwise. */
2918 static struct lwp_info *
2919 linux_nat_filter_event (int lwpid, int status)
2921 struct lwp_info *lp;
2922 int event = linux_ptrace_get_extended_event (status);
2924 lp = find_lwp_pid (ptid_t (lwpid));
2926 /* Check for stop events reported by a process we didn't already
2927 know about - anything not already in our LWP list.
2929 If we're expecting to receive stopped processes after
2930 fork, vfork, and clone events, then we'll just add the
2931 new one to our list and go back to waiting for the event
2932 to be reported - the stopped process might be returned
2933 from waitpid before or after the event is.
2935 But note the case of a non-leader thread exec'ing after the
2936 leader having exited, and gone from our lists. The non-leader
2937 thread changes its tid to the tgid. */
2939 if (WIFSTOPPED (status) && lp == NULL
2940 && (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
2942 /* A multi-thread exec after we had seen the leader exiting. */
2943 if (debug_linux_nat)
2944 fprintf_unfiltered (gdb_stdlog,
2945 "LLW: Re-adding thread group leader LWP %d.\n",
2948 lp = add_lwp (ptid_t (lwpid, lwpid, 0));
2951 add_thread (lp->ptid);
2954 if (WIFSTOPPED (status) && !lp)
2956 if (debug_linux_nat)
2957 fprintf_unfiltered (gdb_stdlog,
2958 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2959 (long) lwpid, status_to_str (status));
2960 add_to_pid_list (&stopped_pids, lwpid, status);
2964 /* Make sure we don't report an event for the exit of an LWP not in
2965 our list, i.e. not part of the current process. This can happen
2966 if we detach from a program we originally forked and then it
2968 if (!WIFSTOPPED (status) && !lp)
2971 /* This LWP is stopped now. (And if dead, this prevents it from
2972 ever being continued.) */
2975 if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
2977 struct inferior *inf = find_inferior_pid (lp->ptid.pid ());
2978 int options = linux_nat_ptrace_options (inf->attach_flag);
2980 linux_enable_event_reporting (lp->ptid.lwp (), options);
2981 lp->must_set_ptrace_flags = 0;
2984 /* Handle GNU/Linux's syscall SIGTRAPs. */
2985 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2987 /* No longer need the sysgood bit. The ptrace event ends up
2988 recorded in lp->waitstatus if we care for it. We can carry
2989 on handling the event like a regular SIGTRAP from here
2991 status = W_STOPCODE (SIGTRAP);
2992 if (linux_handle_syscall_trap (lp, 0))
2997 /* Almost all other ptrace-stops are known to be outside of system
2998 calls, with further exceptions in linux_handle_extended_wait. */
2999 lp->syscall_state = TARGET_WAITKIND_IGNORE;
3002 /* Handle GNU/Linux's extended waitstatus for trace events. */
3003 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
3004 && linux_is_extended_waitstatus (status))
3006 if (debug_linux_nat)
3007 fprintf_unfiltered (gdb_stdlog,
3008 "LLW: Handling extended status 0x%06x\n",
3010 if (linux_handle_extended_wait (lp, status))
3014 /* Check if the thread has exited. */
3015 if (WIFEXITED (status) || WIFSIGNALED (status))
3017 if (!report_thread_events
3018 && num_lwps (lp->ptid.pid ()) > 1)
3020 if (debug_linux_nat)
3021 fprintf_unfiltered (gdb_stdlog,
3022 "LLW: %s exited.\n",
3023 target_pid_to_str (lp->ptid));
3025 /* If there is at least one more LWP, then the exit signal
3026 was not the end of the debugged application and should be
3032 /* Note that even if the leader was ptrace-stopped, it can still
3033 exit, if e.g., some other thread brings down the whole
3034 process (calls `exit'). So don't assert that the lwp is
3036 if (debug_linux_nat)
3037 fprintf_unfiltered (gdb_stdlog,
3038 "LWP %ld exited (resumed=%d)\n",
3039 lp->ptid.lwp (), lp->resumed);
3041 /* Dead LWP's aren't expected to reported a pending sigstop. */
3044 /* Store the pending event in the waitstatus, because
3045 W_EXITCODE(0,0) == 0. */
3046 store_waitstatus (&lp->waitstatus, status);
3050 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3051 an attempt to stop an LWP. */
3053 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3057 if (lp->last_resume_kind == resume_stop)
3059 if (debug_linux_nat)
3060 fprintf_unfiltered (gdb_stdlog,
3061 "LLW: resume_stop SIGSTOP caught for %s.\n",
3062 target_pid_to_str (lp->ptid));
3066 /* This is a delayed SIGSTOP. Filter out the event. */
3068 if (debug_linux_nat)
3069 fprintf_unfiltered (gdb_stdlog,
3070 "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
3072 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3073 target_pid_to_str (lp->ptid));
3075 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3076 gdb_assert (lp->resumed);
3081 /* Make sure we don't report a SIGINT that we have already displayed
3082 for another thread. */
3083 if (lp->ignore_sigint
3084 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3086 if (debug_linux_nat)
3087 fprintf_unfiltered (gdb_stdlog,
3088 "LLW: Delayed SIGINT caught for %s.\n",
3089 target_pid_to_str (lp->ptid));
3091 /* This is a delayed SIGINT. */
3092 lp->ignore_sigint = 0;
3094 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3095 if (debug_linux_nat)
3096 fprintf_unfiltered (gdb_stdlog,
3097 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3099 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3100 target_pid_to_str (lp->ptid));
3101 gdb_assert (lp->resumed);
3103 /* Discard the event. */
3107 /* Don't report signals that GDB isn't interested in, such as
3108 signals that are neither printed nor stopped upon. Stopping all
3109 threads can be a bit time-consuming so if we want decent
3110 performance with heavily multi-threaded programs, especially when
3111 they're using a high frequency timer, we'd better avoid it if we
3113 if (WIFSTOPPED (status))
3115 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3117 if (!target_is_non_stop_p ())
3119 /* Only do the below in all-stop, as we currently use SIGSTOP
3120 to implement target_stop (see linux_nat_stop) in
3122 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3124 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3125 forwarded to the entire process group, that is, all LWPs
3126 will receive it - unless they're using CLONE_THREAD to
3127 share signals. Since we only want to report it once, we
3128 mark it as ignored for all LWPs except this one. */
3129 iterate_over_lwps (ptid_t (lp->ptid.pid ()),
3130 set_ignore_sigint, NULL);
3131 lp->ignore_sigint = 0;
3134 maybe_clear_ignore_sigint (lp);
3137 /* When using hardware single-step, we need to report every signal.
3138 Otherwise, signals in pass_mask may be short-circuited
3139 except signals that might be caused by a breakpoint. */
3141 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status))
3142 && !linux_wstatus_maybe_breakpoint (status))
3144 linux_resume_one_lwp (lp, lp->step, signo);
3145 if (debug_linux_nat)
3146 fprintf_unfiltered (gdb_stdlog,
3147 "LLW: %s %s, %s (preempt 'handle')\n",
3149 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3150 target_pid_to_str (lp->ptid),
3151 (signo != GDB_SIGNAL_0
3152 ? strsignal (gdb_signal_to_host (signo))
3158 /* An interesting event. */
3160 lp->status = status;
3161 save_stop_reason (lp);
3165 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3166 their exits until all other threads in the group have exited. */
3169 check_zombie_leaders (void)
3171 struct inferior *inf;
3175 struct lwp_info *leader_lp;
3180 leader_lp = find_lwp_pid (ptid_t (inf->pid));
3181 if (leader_lp != NULL
3182 /* Check if there are other threads in the group, as we may
3183 have raced with the inferior simply exiting. */
3184 && num_lwps (inf->pid) > 1
3185 && linux_proc_pid_is_zombie (inf->pid))
3187 if (debug_linux_nat)
3188 fprintf_unfiltered (gdb_stdlog,
3189 "CZL: Thread group leader %d zombie "
3190 "(it exited, or another thread execd).\n",
3193 /* A leader zombie can mean one of two things:
3195 - It exited, and there's an exit status pending
3196 available, or only the leader exited (not the whole
3197 program). In the latter case, we can't waitpid the
3198 leader's exit status until all other threads are gone.
3200 - There are 3 or more threads in the group, and a thread
3201 other than the leader exec'd. See comments on exec
3202 events at the top of the file. We could try
3203 distinguishing the exit and exec cases, by waiting once
3204 more, and seeing if something comes out, but it doesn't
3205 sound useful. The previous leader _does_ go away, and
3206 we'll re-add the new one once we see the exec event
3207 (which is just the same as what would happen if the
3208 previous leader did exit voluntarily before some other
3211 if (debug_linux_nat)
3212 fprintf_unfiltered (gdb_stdlog,
3213 "CZL: Thread group leader %d vanished.\n",
3215 exit_lwp (leader_lp);
3220 /* Convenience function that is called when the kernel reports an exit
3221 event. This decides whether to report the event to GDB as a
3222 process exit event, a thread exit event, or to suppress the
3226 filter_exit_event (struct lwp_info *event_child,
3227 struct target_waitstatus *ourstatus)
3229 ptid_t ptid = event_child->ptid;
3231 if (num_lwps (ptid.pid ()) > 1)
3233 if (report_thread_events)
3234 ourstatus->kind = TARGET_WAITKIND_THREAD_EXITED;
3236 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3238 exit_lwp (event_child);
3245 linux_nat_wait_1 (ptid_t ptid, struct target_waitstatus *ourstatus,
3249 enum resume_kind last_resume_kind;
3250 struct lwp_info *lp;
3253 if (debug_linux_nat)
3254 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3256 /* The first time we get here after starting a new inferior, we may
3257 not have added it to the LWP list yet - this is the earliest
3258 moment at which we know its PID. */
3259 if (inferior_ptid.is_pid ())
3261 /* Upgrade the main thread's ptid. */
3262 thread_change_ptid (inferior_ptid,
3263 ptid_t (inferior_ptid.pid (),
3264 inferior_ptid.pid (), 0));
3266 lp = add_initial_lwp (inferior_ptid);
3270 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3271 block_child_signals (&prev_mask);
3273 /* First check if there is a LWP with a wait status pending. */
3274 lp = iterate_over_lwps (ptid, status_callback, NULL);
3277 if (debug_linux_nat)
3278 fprintf_unfiltered (gdb_stdlog,
3279 "LLW: Using pending wait status %s for %s.\n",
3280 status_to_str (lp->status),
3281 target_pid_to_str (lp->ptid));
3284 /* But if we don't find a pending event, we'll have to wait. Always
3285 pull all events out of the kernel. We'll randomly select an
3286 event LWP out of all that have events, to prevent starvation. */
3292 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3295 - If the thread group leader exits while other threads in the
3296 thread group still exist, waitpid(TGID, ...) hangs. That
3297 waitpid won't return an exit status until the other threads
3298 in the group are reapped.
3300 - When a non-leader thread execs, that thread just vanishes
3301 without reporting an exit (so we'd hang if we waited for it
3302 explicitly in that case). The exec event is reported to
3306 lwpid = my_waitpid (-1, &status, __WALL | WNOHANG);
3308 if (debug_linux_nat)
3309 fprintf_unfiltered (gdb_stdlog,
3310 "LNW: waitpid(-1, ...) returned %d, %s\n",
3311 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3315 if (debug_linux_nat)
3317 fprintf_unfiltered (gdb_stdlog,
3318 "LLW: waitpid %ld received %s\n",
3319 (long) lwpid, status_to_str (status));
3322 linux_nat_filter_event (lwpid, status);
3323 /* Retry until nothing comes out of waitpid. A single
3324 SIGCHLD can indicate more than one child stopped. */
3328 /* Now that we've pulled all events out of the kernel, resume
3329 LWPs that don't have an interesting event to report. */
3330 iterate_over_lwps (minus_one_ptid,
3331 resume_stopped_resumed_lwps, &minus_one_ptid);
3333 /* ... and find an LWP with a status to report to the core, if
3335 lp = iterate_over_lwps (ptid, status_callback, NULL);
3339 /* Check for zombie thread group leaders. Those can't be reaped
3340 until all other threads in the thread group are. */
3341 check_zombie_leaders ();
3343 /* If there are no resumed children left, bail. We'd be stuck
3344 forever in the sigsuspend call below otherwise. */
3345 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3347 if (debug_linux_nat)
3348 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3350 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3352 restore_child_signals_mask (&prev_mask);
3353 return minus_one_ptid;
3356 /* No interesting event to report to the core. */
3358 if (target_options & TARGET_WNOHANG)
3360 if (debug_linux_nat)
3361 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3363 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3364 restore_child_signals_mask (&prev_mask);
3365 return minus_one_ptid;
3368 /* We shouldn't end up here unless we want to try again. */
3369 gdb_assert (lp == NULL);
3371 /* Block until we get an event reported with SIGCHLD. */
3377 status = lp->status;
3380 if (!target_is_non_stop_p ())
3382 /* Now stop all other LWP's ... */
3383 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3385 /* ... and wait until all of them have reported back that
3386 they're no longer running. */
3387 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3390 /* If we're not waiting for a specific LWP, choose an event LWP from
3391 among those that have had events. Giving equal priority to all
3392 LWPs that have had events helps prevent starvation. */
3393 if (ptid == minus_one_ptid || ptid.is_pid ())
3394 select_event_lwp (ptid, &lp, &status);
3396 gdb_assert (lp != NULL);
3398 /* Now that we've selected our final event LWP, un-adjust its PC if
3399 it was a software breakpoint, and we can't reliably support the
3400 "stopped by software breakpoint" stop reason. */
3401 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
3402 && !USE_SIGTRAP_SIGINFO)
3404 struct regcache *regcache = get_thread_regcache (lp->ptid);
3405 struct gdbarch *gdbarch = regcache->arch ();
3406 int decr_pc = gdbarch_decr_pc_after_break (gdbarch);
3412 pc = regcache_read_pc (regcache);
3413 regcache_write_pc (regcache, pc + decr_pc);
3417 /* We'll need this to determine whether to report a SIGSTOP as
3418 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3420 last_resume_kind = lp->last_resume_kind;
3422 if (!target_is_non_stop_p ())
3424 /* In all-stop, from the core's perspective, all LWPs are now
3425 stopped until a new resume action is sent over. */
3426 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3430 resume_clear_callback (lp, NULL);
3433 if (linux_target->low_status_is_event (status))
3435 if (debug_linux_nat)
3436 fprintf_unfiltered (gdb_stdlog,
3437 "LLW: trap ptid is %s.\n",
3438 target_pid_to_str (lp->ptid));
3441 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3443 *ourstatus = lp->waitstatus;
3444 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3447 store_waitstatus (ourstatus, status);
3449 if (debug_linux_nat)
3450 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3452 restore_child_signals_mask (&prev_mask);
3454 if (last_resume_kind == resume_stop
3455 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3456 && WSTOPSIG (status) == SIGSTOP)
3458 /* A thread that has been requested to stop by GDB with
3459 target_stop, and it stopped cleanly, so report as SIG0. The
3460 use of SIGSTOP is an implementation detail. */
3461 ourstatus->value.sig = GDB_SIGNAL_0;
3464 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3465 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3468 lp->core = linux_common_core_of_thread (lp->ptid);
3470 if (ourstatus->kind == TARGET_WAITKIND_EXITED)
3471 return filter_exit_event (lp, ourstatus);
3476 /* Resume LWPs that are currently stopped without any pending status
3477 to report, but are resumed from the core's perspective. */
3480 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3482 ptid_t *wait_ptid_p = (ptid_t *) data;
3486 if (debug_linux_nat)
3487 fprintf_unfiltered (gdb_stdlog,
3488 "RSRL: NOT resuming LWP %s, not stopped\n",
3489 target_pid_to_str (lp->ptid));
3491 else if (!lp->resumed)
3493 if (debug_linux_nat)
3494 fprintf_unfiltered (gdb_stdlog,
3495 "RSRL: NOT resuming LWP %s, not resumed\n",
3496 target_pid_to_str (lp->ptid));
3498 else if (lwp_status_pending_p (lp))
3500 if (debug_linux_nat)
3501 fprintf_unfiltered (gdb_stdlog,
3502 "RSRL: NOT resuming LWP %s, has pending status\n",
3503 target_pid_to_str (lp->ptid));
3507 struct regcache *regcache = get_thread_regcache (lp->ptid);
3508 struct gdbarch *gdbarch = regcache->arch ();
3512 CORE_ADDR pc = regcache_read_pc (regcache);
3513 int leave_stopped = 0;
3515 /* Don't bother if there's a breakpoint at PC that we'd hit
3516 immediately, and we're not waiting for this LWP. */
3517 if (!lp->ptid.matches (*wait_ptid_p))
3519 if (breakpoint_inserted_here_p (regcache->aspace (), pc))
3525 if (debug_linux_nat)
3526 fprintf_unfiltered (gdb_stdlog,
3527 "RSRL: resuming stopped-resumed LWP %s at "
3529 target_pid_to_str (lp->ptid),
3530 paddress (gdbarch, pc),
3533 linux_resume_one_lwp_throw (lp, lp->step, GDB_SIGNAL_0);
3536 CATCH (ex, RETURN_MASK_ERROR)
3538 if (!check_ptrace_stopped_lwp_gone (lp))
3539 throw_exception (ex);
3548 linux_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
3553 if (debug_linux_nat)
3555 char *options_string;
3557 options_string = target_options_to_string (target_options);
3558 fprintf_unfiltered (gdb_stdlog,
3559 "linux_nat_wait: [%s], [%s]\n",
3560 target_pid_to_str (ptid),
3562 xfree (options_string);
3565 /* Flush the async file first. */
3566 if (target_is_async_p ())
3567 async_file_flush ();
3569 /* Resume LWPs that are currently stopped without any pending status
3570 to report, but are resumed from the core's perspective. LWPs get
3571 in this state if we find them stopping at a time we're not
3572 interested in reporting the event (target_wait on a
3573 specific_process, for example, see linux_nat_wait_1), and
3574 meanwhile the event became uninteresting. Don't bother resuming
3575 LWPs we're not going to wait for if they'd stop immediately. */
3576 if (target_is_non_stop_p ())
3577 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3579 event_ptid = linux_nat_wait_1 (ptid, ourstatus, target_options);
3581 /* If we requested any event, and something came out, assume there
3582 may be more. If we requested a specific lwp or process, also
3583 assume there may be more. */
3584 if (target_is_async_p ()
3585 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3586 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3587 || ptid != minus_one_ptid))
3596 kill_one_lwp (pid_t pid)
3598 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3601 kill_lwp (pid, SIGKILL);
3602 if (debug_linux_nat)
3604 int save_errno = errno;
3606 fprintf_unfiltered (gdb_stdlog,
3607 "KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid,
3608 save_errno ? safe_strerror (save_errno) : "OK");
3611 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3614 ptrace (PTRACE_KILL, pid, 0, 0);
3615 if (debug_linux_nat)
3617 int save_errno = errno;
3619 fprintf_unfiltered (gdb_stdlog,
3620 "KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid,
3621 save_errno ? safe_strerror (save_errno) : "OK");
3625 /* Wait for an LWP to die. */
3628 kill_wait_one_lwp (pid_t pid)
3632 /* We must make sure that there are no pending events (delayed
3633 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3634 program doesn't interfere with any following debugging session. */
3638 res = my_waitpid (pid, NULL, __WALL);
3639 if (res != (pid_t) -1)
3641 if (debug_linux_nat)
3642 fprintf_unfiltered (gdb_stdlog,
3643 "KWC: wait %ld received unknown.\n",
3645 /* The Linux kernel sometimes fails to kill a thread
3646 completely after PTRACE_KILL; that goes from the stop
3647 point in do_fork out to the one in get_signal_to_deliver
3648 and waits again. So kill it again. */
3654 gdb_assert (res == -1 && errno == ECHILD);
3657 /* Callback for iterate_over_lwps. */
3660 kill_callback (struct lwp_info *lp, void *data)
3662 kill_one_lwp (lp->ptid.lwp ());
3666 /* Callback for iterate_over_lwps. */
3669 kill_wait_callback (struct lwp_info *lp, void *data)
3671 kill_wait_one_lwp (lp->ptid.lwp ());
3675 /* Kill the fork children of any threads of inferior INF that are
3676 stopped at a fork event. */
3679 kill_unfollowed_fork_children (struct inferior *inf)
3681 struct thread_info *thread;
3683 ALL_NON_EXITED_THREADS (thread)
3684 if (thread->inf == inf)
3686 struct target_waitstatus *ws = &thread->pending_follow;
3688 if (ws->kind == TARGET_WAITKIND_FORKED
3689 || ws->kind == TARGET_WAITKIND_VFORKED)
3691 ptid_t child_ptid = ws->value.related_pid;
3692 int child_pid = child_ptid.pid ();
3693 int child_lwp = child_ptid.lwp ();
3695 kill_one_lwp (child_lwp);
3696 kill_wait_one_lwp (child_lwp);
3698 /* Let the arch-specific native code know this process is
3700 linux_target->low_forget_process (child_pid);
3706 linux_nat_target::kill ()
3708 /* If we're stopped while forking and we haven't followed yet,
3709 kill the other task. We need to do this first because the
3710 parent will be sleeping if this is a vfork. */
3711 kill_unfollowed_fork_children (current_inferior ());
3713 if (forks_exist_p ())
3714 linux_fork_killall ();
3717 ptid_t ptid = ptid_t (inferior_ptid.pid ());
3719 /* Stop all threads before killing them, since ptrace requires
3720 that the thread is stopped to sucessfully PTRACE_KILL. */
3721 iterate_over_lwps (ptid, stop_callback, NULL);
3722 /* ... and wait until all of them have reported back that
3723 they're no longer running. */
3724 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3726 /* Kill all LWP's ... */
3727 iterate_over_lwps (ptid, kill_callback, NULL);
3729 /* ... and wait until we've flushed all events. */
3730 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3733 target_mourn_inferior (inferior_ptid);
3737 linux_nat_target::mourn_inferior ()
3739 int pid = inferior_ptid.pid ();
3741 purge_lwp_list (pid);
3743 if (! forks_exist_p ())
3744 /* Normal case, no other forks available. */
3745 inf_ptrace_target::mourn_inferior ();
3747 /* Multi-fork case. The current inferior_ptid has exited, but
3748 there are other viable forks to debug. Delete the exiting
3749 one and context-switch to the first available. */
3750 linux_fork_mourn_inferior ();
3752 /* Let the arch-specific native code know this process is gone. */
3753 linux_target->low_forget_process (pid);
3756 /* Convert a native/host siginfo object, into/from the siginfo in the
3757 layout of the inferiors' architecture. */
3760 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3762 /* If the low target didn't do anything, then just do a straight
3764 if (!linux_target->low_siginfo_fixup (siginfo, inf_siginfo, direction))
3767 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3769 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3773 static enum target_xfer_status
3774 linux_xfer_siginfo (enum target_object object,
3775 const char *annex, gdb_byte *readbuf,
3776 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3777 ULONGEST *xfered_len)
3781 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3783 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3784 gdb_assert (readbuf || writebuf);
3786 pid = inferior_ptid.lwp ();
3788 pid = inferior_ptid.pid ();
3790 if (offset > sizeof (siginfo))
3791 return TARGET_XFER_E_IO;
3794 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3796 return TARGET_XFER_E_IO;
3798 /* When GDB is built as a 64-bit application, ptrace writes into
3799 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3800 inferior with a 64-bit GDB should look the same as debugging it
3801 with a 32-bit GDB, we need to convert it. GDB core always sees
3802 the converted layout, so any read/write will have to be done
3804 siginfo_fixup (&siginfo, inf_siginfo, 0);
3806 if (offset + len > sizeof (siginfo))
3807 len = sizeof (siginfo) - offset;
3809 if (readbuf != NULL)
3810 memcpy (readbuf, inf_siginfo + offset, len);
3813 memcpy (inf_siginfo + offset, writebuf, len);
3815 /* Convert back to ptrace layout before flushing it out. */
3816 siginfo_fixup (&siginfo, inf_siginfo, 1);
3819 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3821 return TARGET_XFER_E_IO;
3825 return TARGET_XFER_OK;
3828 static enum target_xfer_status
3829 linux_nat_xfer_osdata (enum target_object object,
3830 const char *annex, gdb_byte *readbuf,
3831 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3832 ULONGEST *xfered_len);
3834 static enum target_xfer_status
3835 linux_proc_xfer_spu (enum target_object object,
3836 const char *annex, gdb_byte *readbuf,
3837 const gdb_byte *writebuf,
3838 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len);
3840 static enum target_xfer_status
3841 linux_proc_xfer_partial (enum target_object object,
3842 const char *annex, gdb_byte *readbuf,
3843 const gdb_byte *writebuf,
3844 ULONGEST offset, LONGEST len, ULONGEST *xfered_len);
3846 enum target_xfer_status
3847 linux_nat_target::xfer_partial (enum target_object object,
3848 const char *annex, gdb_byte *readbuf,
3849 const gdb_byte *writebuf,
3850 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3852 enum target_xfer_status xfer;
3854 if (object == TARGET_OBJECT_SIGNAL_INFO)
3855 return linux_xfer_siginfo (object, annex, readbuf, writebuf,
3856 offset, len, xfered_len);
3858 /* The target is connected but no live inferior is selected. Pass
3859 this request down to a lower stratum (e.g., the executable
3861 if (object == TARGET_OBJECT_MEMORY && inferior_ptid == null_ptid)
3862 return TARGET_XFER_EOF;
3864 if (object == TARGET_OBJECT_AUXV)
3865 return memory_xfer_auxv (this, object, annex, readbuf, writebuf,
3866 offset, len, xfered_len);
3868 if (object == TARGET_OBJECT_OSDATA)
3869 return linux_nat_xfer_osdata (object, annex, readbuf, writebuf,
3870 offset, len, xfered_len);
3872 if (object == TARGET_OBJECT_SPU)
3873 return linux_proc_xfer_spu (object, annex, readbuf, writebuf,
3874 offset, len, xfered_len);
3876 /* GDB calculates all addresses in the largest possible address
3878 The address width must be masked before its final use - either by
3879 linux_proc_xfer_partial or inf_ptrace_target::xfer_partial.
3881 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
3883 if (object == TARGET_OBJECT_MEMORY)
3885 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
3887 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
3888 offset &= ((ULONGEST) 1 << addr_bit) - 1;
3891 xfer = linux_proc_xfer_partial (object, annex, readbuf, writebuf,
3892 offset, len, xfered_len);
3893 if (xfer != TARGET_XFER_EOF)
3896 return inf_ptrace_target::xfer_partial (object, annex, readbuf, writebuf,
3897 offset, len, xfered_len);
3901 linux_nat_target::thread_alive (ptid_t ptid)
3903 /* As long as a PTID is in lwp list, consider it alive. */
3904 return find_lwp_pid (ptid) != NULL;
3907 /* Implement the to_update_thread_list target method for this
3911 linux_nat_target::update_thread_list ()
3913 struct lwp_info *lwp;
3915 /* We add/delete threads from the list as clone/exit events are
3916 processed, so just try deleting exited threads still in the
3918 delete_exited_threads ();
3920 /* Update the processor core that each lwp/thread was last seen
3924 /* Avoid accessing /proc if the thread hasn't run since we last
3925 time we fetched the thread's core. Accessing /proc becomes
3926 noticeably expensive when we have thousands of LWPs. */
3927 if (lwp->core == -1)
3928 lwp->core = linux_common_core_of_thread (lwp->ptid);
3933 linux_nat_target::pid_to_str (ptid_t ptid)
3935 static char buf[64];
3938 && (ptid.pid () != ptid.lwp ()
3939 || num_lwps (ptid.pid ()) > 1))
3941 snprintf (buf, sizeof (buf), "LWP %ld", ptid.lwp ());
3945 return normal_pid_to_str (ptid);
3949 linux_nat_target::thread_name (struct thread_info *thr)
3951 return linux_proc_tid_get_name (thr->ptid);
3954 /* Accepts an integer PID; Returns a string representing a file that
3955 can be opened to get the symbols for the child process. */
3958 linux_nat_target::pid_to_exec_file (int pid)
3960 return linux_proc_pid_to_exec_file (pid);
3963 /* Implement the to_xfer_partial target method using /proc/<pid>/mem.
3964 Because we can use a single read/write call, this can be much more
3965 efficient than banging away at PTRACE_PEEKTEXT. */
3967 static enum target_xfer_status
3968 linux_proc_xfer_partial (enum target_object object,
3969 const char *annex, gdb_byte *readbuf,
3970 const gdb_byte *writebuf,
3971 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
3977 if (object != TARGET_OBJECT_MEMORY)
3978 return TARGET_XFER_EOF;
3980 /* Don't bother for one word. */
3981 if (len < 3 * sizeof (long))
3982 return TARGET_XFER_EOF;
3984 /* We could keep this file open and cache it - possibly one per
3985 thread. That requires some juggling, but is even faster. */
3986 xsnprintf (filename, sizeof filename, "/proc/%ld/mem",
3987 inferior_ptid.lwp ());
3988 fd = gdb_open_cloexec (filename, ((readbuf ? O_RDONLY : O_WRONLY)
3991 return TARGET_XFER_EOF;
3993 /* Use pread64/pwrite64 if available, since they save a syscall and can
3994 handle 64-bit offsets even on 32-bit platforms (for instance, SPARC
3995 debugging a SPARC64 application). */
3997 ret = (readbuf ? pread64 (fd, readbuf, len, offset)
3998 : pwrite64 (fd, writebuf, len, offset));
4000 ret = lseek (fd, offset, SEEK_SET);
4002 ret = (readbuf ? read (fd, readbuf, len)
4003 : write (fd, writebuf, len));
4008 if (ret == -1 || ret == 0)
4009 return TARGET_XFER_EOF;
4013 return TARGET_XFER_OK;
4018 /* Enumerate spufs IDs for process PID. */
4020 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
4022 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4024 LONGEST written = 0;
4027 struct dirent *entry;
4029 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4030 dir = opendir (path);
4035 while ((entry = readdir (dir)) != NULL)
4041 fd = atoi (entry->d_name);
4045 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4046 if (stat (path, &st) != 0)
4048 if (!S_ISDIR (st.st_mode))
4051 if (statfs (path, &stfs) != 0)
4053 if (stfs.f_type != SPUFS_MAGIC)
4056 if (pos >= offset && pos + 4 <= offset + len)
4058 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4068 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4069 object type, using the /proc file system. */
4071 static enum target_xfer_status
4072 linux_proc_xfer_spu (enum target_object object,
4073 const char *annex, gdb_byte *readbuf,
4074 const gdb_byte *writebuf,
4075 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4080 int pid = inferior_ptid.lwp ();
4085 return TARGET_XFER_E_IO;
4088 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4091 return TARGET_XFER_E_IO;
4093 return TARGET_XFER_EOF;
4096 *xfered_len = (ULONGEST) l;
4097 return TARGET_XFER_OK;
4102 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4103 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4105 return TARGET_XFER_E_IO;
4108 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4111 return TARGET_XFER_EOF;
4115 ret = write (fd, writebuf, (size_t) len);
4117 ret = read (fd, readbuf, (size_t) len);
4122 return TARGET_XFER_E_IO;
4124 return TARGET_XFER_EOF;
4127 *xfered_len = (ULONGEST) ret;
4128 return TARGET_XFER_OK;
4133 /* Parse LINE as a signal set and add its set bits to SIGS. */
4136 add_line_to_sigset (const char *line, sigset_t *sigs)
4138 int len = strlen (line) - 1;
4142 if (line[len] != '\n')
4143 error (_("Could not parse signal set: %s"), line);
4151 if (*p >= '0' && *p <= '9')
4153 else if (*p >= 'a' && *p <= 'f')
4154 digit = *p - 'a' + 10;
4156 error (_("Could not parse signal set: %s"), line);
4161 sigaddset (sigs, signum + 1);
4163 sigaddset (sigs, signum + 2);
4165 sigaddset (sigs, signum + 3);
4167 sigaddset (sigs, signum + 4);
4173 /* Find process PID's pending signals from /proc/pid/status and set
4177 linux_proc_pending_signals (int pid, sigset_t *pending,
4178 sigset_t *blocked, sigset_t *ignored)
4180 char buffer[PATH_MAX], fname[PATH_MAX];
4182 sigemptyset (pending);
4183 sigemptyset (blocked);
4184 sigemptyset (ignored);
4185 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4186 gdb_file_up procfile = gdb_fopen_cloexec (fname, "r");
4187 if (procfile == NULL)
4188 error (_("Could not open %s"), fname);
4190 while (fgets (buffer, PATH_MAX, procfile.get ()) != NULL)
4192 /* Normal queued signals are on the SigPnd line in the status
4193 file. However, 2.6 kernels also have a "shared" pending
4194 queue for delivering signals to a thread group, so check for
4197 Unfortunately some Red Hat kernels include the shared pending
4198 queue but not the ShdPnd status field. */
4200 if (startswith (buffer, "SigPnd:\t"))
4201 add_line_to_sigset (buffer + 8, pending);
4202 else if (startswith (buffer, "ShdPnd:\t"))
4203 add_line_to_sigset (buffer + 8, pending);
4204 else if (startswith (buffer, "SigBlk:\t"))
4205 add_line_to_sigset (buffer + 8, blocked);
4206 else if (startswith (buffer, "SigIgn:\t"))
4207 add_line_to_sigset (buffer + 8, ignored);
4211 static enum target_xfer_status
4212 linux_nat_xfer_osdata (enum target_object object,
4213 const char *annex, gdb_byte *readbuf,
4214 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4215 ULONGEST *xfered_len)
4217 gdb_assert (object == TARGET_OBJECT_OSDATA);
4219 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4220 if (*xfered_len == 0)
4221 return TARGET_XFER_EOF;
4223 return TARGET_XFER_OK;
4227 cleanup_target_stop (void *arg)
4229 ptid_t *ptid = (ptid_t *) arg;
4231 gdb_assert (arg != NULL);
4234 target_continue_no_signal (*ptid);
4237 std::vector<static_tracepoint_marker>
4238 linux_nat_target::static_tracepoint_markers_by_strid (const char *strid)
4240 char s[IPA_CMD_BUF_SIZE];
4241 struct cleanup *old_chain;
4242 int pid = inferior_ptid.pid ();
4243 std::vector<static_tracepoint_marker> markers;
4245 ptid_t ptid = ptid_t (pid, 0, 0);
4246 static_tracepoint_marker marker;
4251 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4252 s[sizeof ("qTfSTM")] = 0;
4254 agent_run_command (pid, s, strlen (s) + 1);
4256 old_chain = make_cleanup (cleanup_target_stop, &ptid);
4262 parse_static_tracepoint_marker_definition (p, &p, &marker);
4264 if (strid == NULL || marker.str_id == strid)
4265 markers.push_back (std::move (marker));
4267 while (*p++ == ','); /* comma-separated list */
4269 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4270 s[sizeof ("qTsSTM")] = 0;
4271 agent_run_command (pid, s, strlen (s) + 1);
4275 do_cleanups (old_chain);
4280 /* target_is_async_p implementation. */
4283 linux_nat_target::is_async_p ()
4285 return linux_is_async_p ();
4288 /* target_can_async_p implementation. */
4291 linux_nat_target::can_async_p ()
4293 /* We're always async, unless the user explicitly prevented it with the
4294 "maint set target-async" command. */
4295 return target_async_permitted;
4299 linux_nat_target::supports_non_stop ()
4304 /* to_always_non_stop_p implementation. */
4307 linux_nat_target::always_non_stop_p ()
4312 /* True if we want to support multi-process. To be removed when GDB
4313 supports multi-exec. */
4315 int linux_multi_process = 1;
4318 linux_nat_target::supports_multi_process ()
4320 return linux_multi_process;
4324 linux_nat_target::supports_disable_randomization ()
4326 #ifdef HAVE_PERSONALITY
4333 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4334 so we notice when any child changes state, and notify the
4335 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4336 above to wait for the arrival of a SIGCHLD. */
4339 sigchld_handler (int signo)
4341 int old_errno = errno;
4343 if (debug_linux_nat)
4344 ui_file_write_async_safe (gdb_stdlog,
4345 "sigchld\n", sizeof ("sigchld\n") - 1);
4347 if (signo == SIGCHLD
4348 && linux_nat_event_pipe[0] != -1)
4349 async_file_mark (); /* Let the event loop know that there are
4350 events to handle. */
4355 /* Callback registered with the target events file descriptor. */
4358 handle_target_event (int error, gdb_client_data client_data)
4360 inferior_event_handler (INF_REG_EVENT, NULL);
4363 /* Create/destroy the target events pipe. Returns previous state. */
4366 linux_async_pipe (int enable)
4368 int previous = linux_is_async_p ();
4370 if (previous != enable)
4374 /* Block child signals while we create/destroy the pipe, as
4375 their handler writes to it. */
4376 block_child_signals (&prev_mask);
4380 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4381 internal_error (__FILE__, __LINE__,
4382 "creating event pipe failed.");
4384 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4385 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4389 close (linux_nat_event_pipe[0]);
4390 close (linux_nat_event_pipe[1]);
4391 linux_nat_event_pipe[0] = -1;
4392 linux_nat_event_pipe[1] = -1;
4395 restore_child_signals_mask (&prev_mask);
4401 /* target_async implementation. */
4404 linux_nat_target::async (int enable)
4408 if (!linux_async_pipe (1))
4410 add_file_handler (linux_nat_event_pipe[0],
4411 handle_target_event, NULL);
4412 /* There may be pending events to handle. Tell the event loop
4419 delete_file_handler (linux_nat_event_pipe[0]);
4420 linux_async_pipe (0);
4425 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4429 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4433 if (debug_linux_nat)
4434 fprintf_unfiltered (gdb_stdlog,
4435 "LNSL: running -> suspending %s\n",
4436 target_pid_to_str (lwp->ptid));
4439 if (lwp->last_resume_kind == resume_stop)
4441 if (debug_linux_nat)
4442 fprintf_unfiltered (gdb_stdlog,
4443 "linux-nat: already stopping LWP %ld at "
4449 stop_callback (lwp, NULL);
4450 lwp->last_resume_kind = resume_stop;
4454 /* Already known to be stopped; do nothing. */
4456 if (debug_linux_nat)
4458 if (find_thread_ptid (lwp->ptid)->stop_requested)
4459 fprintf_unfiltered (gdb_stdlog,
4460 "LNSL: already stopped/stop_requested %s\n",
4461 target_pid_to_str (lwp->ptid));
4463 fprintf_unfiltered (gdb_stdlog,
4464 "LNSL: already stopped/no "
4465 "stop_requested yet %s\n",
4466 target_pid_to_str (lwp->ptid));
4473 linux_nat_target::stop (ptid_t ptid)
4475 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4479 linux_nat_target::close ()
4481 /* Unregister from the event loop. */
4485 inf_ptrace_target::close ();
4488 /* When requests are passed down from the linux-nat layer to the
4489 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4490 used. The address space pointer is stored in the inferior object,
4491 but the common code that is passed such ptid can't tell whether
4492 lwpid is a "main" process id or not (it assumes so). We reverse
4493 look up the "main" process id from the lwp here. */
4495 struct address_space *
4496 linux_nat_target::thread_address_space (ptid_t ptid)
4498 struct lwp_info *lwp;
4499 struct inferior *inf;
4502 if (ptid.lwp () == 0)
4504 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4506 lwp = find_lwp_pid (ptid);
4507 pid = lwp->ptid.pid ();
4511 /* A (pid,lwpid,0) ptid. */
4515 inf = find_inferior_pid (pid);
4516 gdb_assert (inf != NULL);
4520 /* Return the cached value of the processor core for thread PTID. */
4523 linux_nat_target::core_of_thread (ptid_t ptid)
4525 struct lwp_info *info = find_lwp_pid (ptid);
4532 /* Implementation of to_filesystem_is_local. */
4535 linux_nat_target::filesystem_is_local ()
4537 struct inferior *inf = current_inferior ();
4539 if (inf->fake_pid_p || inf->pid == 0)
4542 return linux_ns_same (inf->pid, LINUX_NS_MNT);
4545 /* Convert the INF argument passed to a to_fileio_* method
4546 to a process ID suitable for passing to its corresponding
4547 linux_mntns_* function. If INF is non-NULL then the
4548 caller is requesting the filesystem seen by INF. If INF
4549 is NULL then the caller is requesting the filesystem seen
4550 by the GDB. We fall back to GDB's filesystem in the case
4551 that INF is non-NULL but its PID is unknown. */
4554 linux_nat_fileio_pid_of (struct inferior *inf)
4556 if (inf == NULL || inf->fake_pid_p || inf->pid == 0)
4562 /* Implementation of to_fileio_open. */
4565 linux_nat_target::fileio_open (struct inferior *inf, const char *filename,
4566 int flags, int mode, int warn_if_slow,
4573 if (fileio_to_host_openflags (flags, &nat_flags) == -1
4574 || fileio_to_host_mode (mode, &nat_mode) == -1)
4576 *target_errno = FILEIO_EINVAL;
4580 fd = linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf),
4581 filename, nat_flags, nat_mode);
4583 *target_errno = host_to_fileio_error (errno);
4588 /* Implementation of to_fileio_readlink. */
4590 gdb::optional<std::string>
4591 linux_nat_target::fileio_readlink (struct inferior *inf, const char *filename,
4597 len = linux_mntns_readlink (linux_nat_fileio_pid_of (inf),
4598 filename, buf, sizeof (buf));
4601 *target_errno = host_to_fileio_error (errno);
4605 return std::string (buf, len);
4608 /* Implementation of to_fileio_unlink. */
4611 linux_nat_target::fileio_unlink (struct inferior *inf, const char *filename,
4616 ret = linux_mntns_unlink (linux_nat_fileio_pid_of (inf),
4619 *target_errno = host_to_fileio_error (errno);
4624 /* Implementation of the to_thread_events method. */
4627 linux_nat_target::thread_events (int enable)
4629 report_thread_events = enable;
4632 linux_nat_target::linux_nat_target ()
4634 /* We don't change the stratum; this target will sit at
4635 process_stratum and thread_db will set at thread_stratum. This
4636 is a little strange, since this is a multi-threaded-capable
4637 target, but we want to be on the stack below thread_db, and we
4638 also want to be used for single-threaded processes. */
4641 /* See linux-nat.h. */
4644 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4653 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4656 memset (siginfo, 0, sizeof (*siginfo));
4662 /* See nat/linux-nat.h. */
4665 current_lwp_ptid (void)
4667 gdb_assert (inferior_ptid.lwp_p ());
4668 return inferior_ptid;
4672 _initialize_linux_nat (void)
4674 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4675 &debug_linux_nat, _("\
4676 Set debugging of GNU/Linux lwp module."), _("\
4677 Show debugging of GNU/Linux lwp module."), _("\
4678 Enables printf debugging output."),
4680 show_debug_linux_nat,
4681 &setdebuglist, &showdebuglist);
4683 add_setshow_boolean_cmd ("linux-namespaces", class_maintenance,
4684 &debug_linux_namespaces, _("\
4685 Set debugging of GNU/Linux namespaces module."), _("\
4686 Show debugging of GNU/Linux namespaces module."), _("\
4687 Enables printf debugging output."),
4690 &setdebuglist, &showdebuglist);
4692 /* Save this mask as the default. */
4693 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4695 /* Install a SIGCHLD handler. */
4696 sigchld_action.sa_handler = sigchld_handler;
4697 sigemptyset (&sigchld_action.sa_mask);
4698 sigchld_action.sa_flags = SA_RESTART;
4700 /* Make it the default. */
4701 sigaction (SIGCHLD, &sigchld_action, NULL);
4703 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4704 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
4705 sigdelset (&suspend_mask, SIGCHLD);
4707 sigemptyset (&blocked_mask);
4709 lwp_lwpid_htab_create ();
4713 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4714 the GNU/Linux Threads library and therefore doesn't really belong
4717 /* Return the set of signals used by the threads library in *SET. */
4720 lin_thread_get_thread_signals (sigset_t *set)
4724 /* NPTL reserves the first two RT signals, but does not provide any
4725 way for the debugger to query the signal numbers - fortunately
4726 they don't change. */
4727 sigaddset (set, __SIGRTMIN);
4728 sigaddset (set, __SIGRTMIN + 1);