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 warnings and check for supported ptrace
390 ATTACHED should be nonzero iff we attached to the inferior. */
393 linux_init_ptrace (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 ();
401 linux_nat_target::~linux_nat_target ()
405 linux_nat_target::post_attach (int pid)
407 linux_init_ptrace (pid, 1);
411 linux_nat_target::post_startup_inferior (ptid_t ptid)
413 linux_init_ptrace (ptid.pid (), 0);
416 /* Return the number of known LWPs in the tgid given by PID. */
424 for (lp = lwp_list; lp; lp = lp->next)
425 if (lp->ptid.pid () == pid)
431 /* Call delete_lwp with prototype compatible for make_cleanup. */
434 delete_lwp_cleanup (void *lp_voidp)
436 struct lwp_info *lp = (struct lwp_info *) lp_voidp;
438 delete_lwp (lp->ptid);
441 /* Target hook for follow_fork. On entry inferior_ptid must be the
442 ptid of the followed inferior. At return, inferior_ptid will be
446 linux_nat_target::follow_fork (int follow_child, int detach_fork)
450 struct lwp_info *child_lp = NULL;
451 int status = W_STOPCODE (0);
453 ptid_t parent_ptid, child_ptid;
454 int parent_pid, child_pid;
456 has_vforked = (inferior_thread ()->pending_follow.kind
457 == TARGET_WAITKIND_VFORKED);
458 parent_ptid = inferior_ptid;
459 child_ptid = inferior_thread ()->pending_follow.value.related_pid;
460 parent_pid = parent_ptid.lwp ();
461 child_pid = child_ptid.lwp ();
463 /* We're already attached to the parent, by default. */
464 child_lp = add_lwp (child_ptid);
465 child_lp->stopped = 1;
466 child_lp->last_resume_kind = resume_stop;
468 /* Detach new forked process? */
471 struct cleanup *old_chain = make_cleanup (delete_lwp_cleanup,
474 linux_target->low_prepare_to_resume (child_lp);
476 /* When debugging an inferior in an architecture that supports
477 hardware single stepping on a kernel without commit
478 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
479 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
480 set if the parent process had them set.
481 To work around this, single step the child process
482 once before detaching to clear the flags. */
484 /* Note that we consult the parent's architecture instead of
485 the child's because there's no inferior for the child at
487 if (!gdbarch_software_single_step_p (target_thread_architecture
490 linux_disable_event_reporting (child_pid);
491 if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
492 perror_with_name (_("Couldn't do single step"));
493 if (my_waitpid (child_pid, &status, 0) < 0)
494 perror_with_name (_("Couldn't wait vfork process"));
497 if (WIFSTOPPED (status))
501 signo = WSTOPSIG (status);
503 && !signal_pass_state (gdb_signal_from_host (signo)))
505 ptrace (PTRACE_DETACH, child_pid, 0, signo);
508 do_cleanups (old_chain);
512 scoped_restore save_inferior_ptid
513 = make_scoped_restore (&inferior_ptid);
514 inferior_ptid = child_ptid;
516 /* Let the thread_db layer learn about this new process. */
517 check_for_thread_db ();
522 struct lwp_info *parent_lp;
524 parent_lp = find_lwp_pid (parent_ptid);
525 gdb_assert (linux_supports_tracefork () >= 0);
527 if (linux_supports_tracevforkdone ())
530 fprintf_unfiltered (gdb_stdlog,
531 "LCFF: waiting for VFORK_DONE on %d\n",
533 parent_lp->stopped = 1;
535 /* We'll handle the VFORK_DONE event like any other
536 event, in target_wait. */
540 /* We can't insert breakpoints until the child has
541 finished with the shared memory region. We need to
542 wait until that happens. Ideal would be to just
544 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
545 - waitpid (parent_pid, &status, __WALL);
546 However, most architectures can't handle a syscall
547 being traced on the way out if it wasn't traced on
550 We might also think to loop, continuing the child
551 until it exits or gets a SIGTRAP. One problem is
552 that the child might call ptrace with PTRACE_TRACEME.
554 There's no simple and reliable way to figure out when
555 the vforked child will be done with its copy of the
556 shared memory. We could step it out of the syscall,
557 two instructions, let it go, and then single-step the
558 parent once. When we have hardware single-step, this
559 would work; with software single-step it could still
560 be made to work but we'd have to be able to insert
561 single-step breakpoints in the child, and we'd have
562 to insert -just- the single-step breakpoint in the
563 parent. Very awkward.
565 In the end, the best we can do is to make sure it
566 runs for a little while. Hopefully it will be out of
567 range of any breakpoints we reinsert. Usually this
568 is only the single-step breakpoint at vfork's return
572 fprintf_unfiltered (gdb_stdlog,
573 "LCFF: no VFORK_DONE "
574 "support, sleeping a bit\n");
578 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
579 and leave it pending. The next linux_nat_resume call
580 will notice a pending event, and bypasses actually
581 resuming the inferior. */
582 parent_lp->status = 0;
583 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
584 parent_lp->stopped = 1;
586 /* If we're in async mode, need to tell the event loop
587 there's something here to process. */
588 if (target_is_async_p ())
595 struct lwp_info *child_lp;
597 child_lp = add_lwp (inferior_ptid);
598 child_lp->stopped = 1;
599 child_lp->last_resume_kind = resume_stop;
601 /* Let the thread_db layer learn about this new process. */
602 check_for_thread_db ();
610 linux_nat_target::insert_fork_catchpoint (int pid)
612 return !linux_supports_tracefork ();
616 linux_nat_target::remove_fork_catchpoint (int pid)
622 linux_nat_target::insert_vfork_catchpoint (int pid)
624 return !linux_supports_tracefork ();
628 linux_nat_target::remove_vfork_catchpoint (int pid)
634 linux_nat_target::insert_exec_catchpoint (int pid)
636 return !linux_supports_tracefork ();
640 linux_nat_target::remove_exec_catchpoint (int pid)
646 linux_nat_target::set_syscall_catchpoint (int pid, bool needed, int any_count,
647 gdb::array_view<const int> syscall_counts)
649 if (!linux_supports_tracesysgood ())
652 /* On GNU/Linux, we ignore the arguments. It means that we only
653 enable the syscall catchpoints, but do not disable them.
655 Also, we do not use the `syscall_counts' information because we do not
656 filter system calls here. We let GDB do the logic for us. */
660 /* List of known LWPs, keyed by LWP PID. This speeds up the common
661 case of mapping a PID returned from the kernel to our corresponding
662 lwp_info data structure. */
663 static htab_t lwp_lwpid_htab;
665 /* Calculate a hash from a lwp_info's LWP PID. */
668 lwp_info_hash (const void *ap)
670 const struct lwp_info *lp = (struct lwp_info *) ap;
671 pid_t pid = lp->ptid.lwp ();
673 return iterative_hash_object (pid, 0);
676 /* Equality function for the lwp_info hash table. Compares the LWP's
680 lwp_lwpid_htab_eq (const void *a, const void *b)
682 const struct lwp_info *entry = (const struct lwp_info *) a;
683 const struct lwp_info *element = (const struct lwp_info *) b;
685 return entry->ptid.lwp () == element->ptid.lwp ();
688 /* Create the lwp_lwpid_htab hash table. */
691 lwp_lwpid_htab_create (void)
693 lwp_lwpid_htab = htab_create (100, lwp_info_hash, lwp_lwpid_htab_eq, NULL);
696 /* Add LP to the hash table. */
699 lwp_lwpid_htab_add_lwp (struct lwp_info *lp)
703 slot = htab_find_slot (lwp_lwpid_htab, lp, INSERT);
704 gdb_assert (slot != NULL && *slot == NULL);
708 /* Head of doubly-linked list of known LWPs. Sorted by reverse
709 creation order. This order is assumed in some cases. E.g.,
710 reaping status after killing alls lwps of a process: the leader LWP
711 must be reaped last. */
712 struct lwp_info *lwp_list;
714 /* Add LP to sorted-by-reverse-creation-order doubly-linked list. */
717 lwp_list_add (struct lwp_info *lp)
720 if (lwp_list != NULL)
725 /* Remove LP from sorted-by-reverse-creation-order doubly-linked
729 lwp_list_remove (struct lwp_info *lp)
731 /* Remove from sorted-by-creation-order list. */
732 if (lp->next != NULL)
733 lp->next->prev = lp->prev;
734 if (lp->prev != NULL)
735 lp->prev->next = lp->next;
742 /* Original signal mask. */
743 static sigset_t normal_mask;
745 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
746 _initialize_linux_nat. */
747 static sigset_t suspend_mask;
749 /* Signals to block to make that sigsuspend work. */
750 static sigset_t blocked_mask;
752 /* SIGCHLD action. */
753 struct sigaction sigchld_action;
755 /* Block child signals (SIGCHLD and linux threads signals), and store
756 the previous mask in PREV_MASK. */
759 block_child_signals (sigset_t *prev_mask)
761 /* Make sure SIGCHLD is blocked. */
762 if (!sigismember (&blocked_mask, SIGCHLD))
763 sigaddset (&blocked_mask, SIGCHLD);
765 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
768 /* Restore child signals mask, previously returned by
769 block_child_signals. */
772 restore_child_signals_mask (sigset_t *prev_mask)
774 sigprocmask (SIG_SETMASK, prev_mask, NULL);
777 /* Mask of signals to pass directly to the inferior. */
778 static sigset_t pass_mask;
780 /* Update signals to pass to the inferior. */
782 linux_nat_target::pass_signals (int numsigs, unsigned char *pass_signals)
786 sigemptyset (&pass_mask);
788 for (signo = 1; signo < NSIG; signo++)
790 int target_signo = gdb_signal_from_host (signo);
791 if (target_signo < numsigs && pass_signals[target_signo])
792 sigaddset (&pass_mask, signo);
798 /* Prototypes for local functions. */
799 static int stop_wait_callback (struct lwp_info *lp, void *data);
800 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
801 static int check_ptrace_stopped_lwp_gone (struct lwp_info *lp);
805 /* Destroy and free LP. */
808 lwp_free (struct lwp_info *lp)
810 /* Let the arch specific bits release arch_lwp_info. */
811 linux_target->low_delete_thread (lp->arch_private);
816 /* Traversal function for purge_lwp_list. */
819 lwp_lwpid_htab_remove_pid (void **slot, void *info)
821 struct lwp_info *lp = (struct lwp_info *) *slot;
822 int pid = *(int *) info;
824 if (lp->ptid.pid () == pid)
826 htab_clear_slot (lwp_lwpid_htab, slot);
827 lwp_list_remove (lp);
834 /* Remove all LWPs belong to PID from the lwp list. */
837 purge_lwp_list (int pid)
839 htab_traverse_noresize (lwp_lwpid_htab, lwp_lwpid_htab_remove_pid, &pid);
842 /* Add the LWP specified by PTID to the list. PTID is the first LWP
843 in the process. Return a pointer to the structure describing the
846 This differs from add_lwp in that we don't let the arch specific
847 bits know about this new thread. Current clients of this callback
848 take the opportunity to install watchpoints in the new thread, and
849 we shouldn't do that for the first thread. If we're spawning a
850 child ("run"), the thread executes the shell wrapper first, and we
851 shouldn't touch it until it execs the program we want to debug.
852 For "attach", it'd be okay to call the callback, but it's not
853 necessary, because watchpoints can't yet have been inserted into
856 static struct lwp_info *
857 add_initial_lwp (ptid_t ptid)
861 gdb_assert (ptid_lwp_p (ptid));
863 lp = XNEW (struct lwp_info);
865 memset (lp, 0, sizeof (struct lwp_info));
867 lp->last_resume_kind = resume_continue;
868 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
873 /* Add to sorted-by-reverse-creation-order list. */
876 /* Add to keyed-by-pid htab. */
877 lwp_lwpid_htab_add_lwp (lp);
882 /* Add the LWP specified by PID to the list. Return a pointer to the
883 structure describing the new LWP. The LWP should already be
886 static struct lwp_info *
887 add_lwp (ptid_t ptid)
891 lp = add_initial_lwp (ptid);
893 /* Let the arch specific bits know about this new thread. Current
894 clients of this callback take the opportunity to install
895 watchpoints in the new thread. We don't do this for the first
896 thread though. See add_initial_lwp. */
897 linux_target->low_new_thread (lp);
902 /* Remove the LWP specified by PID from the list. */
905 delete_lwp (ptid_t ptid)
909 struct lwp_info dummy;
912 slot = htab_find_slot (lwp_lwpid_htab, &dummy, NO_INSERT);
916 lp = *(struct lwp_info **) slot;
917 gdb_assert (lp != NULL);
919 htab_clear_slot (lwp_lwpid_htab, slot);
921 /* Remove from sorted-by-creation-order list. */
922 lwp_list_remove (lp);
928 /* Return a pointer to the structure describing the LWP corresponding
929 to PID. If no corresponding LWP could be found, return NULL. */
931 static struct lwp_info *
932 find_lwp_pid (ptid_t ptid)
936 struct lwp_info dummy;
938 if (ptid_lwp_p (ptid))
943 dummy.ptid = ptid_t (0, lwp, 0);
944 lp = (struct lwp_info *) htab_find (lwp_lwpid_htab, &dummy);
948 /* See nat/linux-nat.h. */
951 iterate_over_lwps (ptid_t filter,
952 iterate_over_lwps_ftype callback,
955 struct lwp_info *lp, *lpnext;
957 for (lp = lwp_list; lp; lp = lpnext)
961 if (ptid_match (lp->ptid, filter))
963 if ((*callback) (lp, data) != 0)
971 /* Update our internal state when changing from one checkpoint to
972 another indicated by NEW_PTID. We can only switch single-threaded
973 applications, so we only create one new LWP, and the previous list
977 linux_nat_switch_fork (ptid_t new_ptid)
981 purge_lwp_list (inferior_ptid.pid ());
983 lp = add_lwp (new_ptid);
986 /* This changes the thread's ptid while preserving the gdb thread
987 num. Also changes the inferior pid, while preserving the
989 thread_change_ptid (inferior_ptid, new_ptid);
991 /* We've just told GDB core that the thread changed target id, but,
992 in fact, it really is a different thread, with different register
994 registers_changed ();
997 /* Handle the exit of a single thread LP. */
1000 exit_lwp (struct lwp_info *lp)
1002 struct thread_info *th = find_thread_ptid (lp->ptid);
1006 if (print_thread_events)
1007 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
1012 delete_lwp (lp->ptid);
1015 /* Wait for the LWP specified by LP, which we have just attached to.
1016 Returns a wait status for that LWP, to cache. */
1019 linux_nat_post_attach_wait (ptid_t ptid, int *signalled)
1021 pid_t new_pid, pid = ptid.lwp ();
1024 if (linux_proc_pid_is_stopped (pid))
1026 if (debug_linux_nat)
1027 fprintf_unfiltered (gdb_stdlog,
1028 "LNPAW: Attaching to a stopped process\n");
1030 /* The process is definitely stopped. It is in a job control
1031 stop, unless the kernel predates the TASK_STOPPED /
1032 TASK_TRACED distinction, in which case it might be in a
1033 ptrace stop. Make sure it is in a ptrace stop; from there we
1034 can kill it, signal it, et cetera.
1036 First make sure there is a pending SIGSTOP. Since we are
1037 already attached, the process can not transition from stopped
1038 to running without a PTRACE_CONT; so we know this signal will
1039 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1040 probably already in the queue (unless this kernel is old
1041 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1042 is not an RT signal, it can only be queued once. */
1043 kill_lwp (pid, SIGSTOP);
1045 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1046 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1047 ptrace (PTRACE_CONT, pid, 0, 0);
1050 /* Make sure the initial process is stopped. The user-level threads
1051 layer might want to poke around in the inferior, and that won't
1052 work if things haven't stabilized yet. */
1053 new_pid = my_waitpid (pid, &status, __WALL);
1054 gdb_assert (pid == new_pid);
1056 if (!WIFSTOPPED (status))
1058 /* The pid we tried to attach has apparently just exited. */
1059 if (debug_linux_nat)
1060 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1061 pid, status_to_str (status));
1065 if (WSTOPSIG (status) != SIGSTOP)
1068 if (debug_linux_nat)
1069 fprintf_unfiltered (gdb_stdlog,
1070 "LNPAW: Received %s after attaching\n",
1071 status_to_str (status));
1078 linux_nat_target::create_inferior (const char *exec_file,
1079 const std::string &allargs,
1080 char **env, int from_tty)
1082 maybe_disable_address_space_randomization restore_personality
1083 (disable_randomization);
1085 /* The fork_child mechanism is synchronous and calls target_wait, so
1086 we have to mask the async mode. */
1088 /* Make sure we report all signals during startup. */
1089 pass_signals (0, NULL);
1091 inf_ptrace_target::create_inferior (exec_file, allargs, env, from_tty);
1094 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1095 already attached. Returns true if a new LWP is found, false
1099 attach_proc_task_lwp_callback (ptid_t ptid)
1101 struct lwp_info *lp;
1103 /* Ignore LWPs we're already attached to. */
1104 lp = find_lwp_pid (ptid);
1107 int lwpid = ptid.lwp ();
1109 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1113 /* Be quiet if we simply raced with the thread exiting.
1114 EPERM is returned if the thread's task still exists, and
1115 is marked as exited or zombie, as well as other
1116 conditions, so in that case, confirm the status in
1117 /proc/PID/status. */
1119 || (err == EPERM && linux_proc_pid_is_gone (lwpid)))
1121 if (debug_linux_nat)
1123 fprintf_unfiltered (gdb_stdlog,
1124 "Cannot attach to lwp %d: "
1125 "thread is gone (%d: %s)\n",
1126 lwpid, err, safe_strerror (err));
1132 = linux_ptrace_attach_fail_reason_string (ptid, err);
1134 warning (_("Cannot attach to lwp %d: %s"),
1135 lwpid, reason.c_str ());
1140 if (debug_linux_nat)
1141 fprintf_unfiltered (gdb_stdlog,
1142 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1143 target_pid_to_str (ptid));
1145 lp = add_lwp (ptid);
1147 /* The next time we wait for this LWP we'll see a SIGSTOP as
1148 PTRACE_ATTACH brings it to a halt. */
1151 /* We need to wait for a stop before being able to make the
1152 next ptrace call on this LWP. */
1153 lp->must_set_ptrace_flags = 1;
1155 /* So that wait collects the SIGSTOP. */
1158 /* Also add the LWP to gdb's thread list, in case a
1159 matching libthread_db is not found (or the process uses
1161 add_thread (lp->ptid);
1162 set_running (lp->ptid, 1);
1163 set_executing (lp->ptid, 1);
1172 linux_nat_target::attach (const char *args, int from_tty)
1174 struct lwp_info *lp;
1178 /* Make sure we report all signals during attach. */
1179 pass_signals (0, NULL);
1183 inf_ptrace_target::attach (args, from_tty);
1185 CATCH (ex, RETURN_MASK_ERROR)
1187 pid_t pid = parse_pid_to_attach (args);
1188 std::string reason = linux_ptrace_attach_fail_reason (pid);
1190 if (!reason.empty ())
1191 throw_error (ex.error, "warning: %s\n%s", reason.c_str (), ex.message);
1193 throw_error (ex.error, "%s", ex.message);
1197 /* The ptrace base target adds the main thread with (pid,0,0)
1198 format. Decorate it with lwp info. */
1199 ptid = ptid_t (inferior_ptid.pid (),
1200 inferior_ptid.pid (),
1202 thread_change_ptid (inferior_ptid, ptid);
1204 /* Add the initial process as the first LWP to the list. */
1205 lp = add_initial_lwp (ptid);
1207 status = linux_nat_post_attach_wait (lp->ptid, &lp->signalled);
1208 if (!WIFSTOPPED (status))
1210 if (WIFEXITED (status))
1212 int exit_code = WEXITSTATUS (status);
1214 target_terminal::ours ();
1215 target_mourn_inferior (inferior_ptid);
1217 error (_("Unable to attach: program exited normally."));
1219 error (_("Unable to attach: program exited with code %d."),
1222 else if (WIFSIGNALED (status))
1224 enum gdb_signal signo;
1226 target_terminal::ours ();
1227 target_mourn_inferior (inferior_ptid);
1229 signo = gdb_signal_from_host (WTERMSIG (status));
1230 error (_("Unable to attach: program terminated with signal "
1232 gdb_signal_to_name (signo),
1233 gdb_signal_to_string (signo));
1236 internal_error (__FILE__, __LINE__,
1237 _("unexpected status %d for PID %ld"),
1238 status, (long) ptid.lwp ());
1243 /* Save the wait status to report later. */
1245 if (debug_linux_nat)
1246 fprintf_unfiltered (gdb_stdlog,
1247 "LNA: waitpid %ld, saving status %s\n",
1248 (long) lp->ptid.pid (), status_to_str (status));
1250 lp->status = status;
1252 /* We must attach to every LWP. If /proc is mounted, use that to
1253 find them now. The inferior may be using raw clone instead of
1254 using pthreads. But even if it is using pthreads, thread_db
1255 walks structures in the inferior's address space to find the list
1256 of threads/LWPs, and those structures may well be corrupted.
1257 Note that once thread_db is loaded, we'll still use it to list
1258 threads and associate pthread info with each LWP. */
1259 linux_proc_attach_tgid_threads (lp->ptid.pid (),
1260 attach_proc_task_lwp_callback);
1262 if (target_can_async_p ())
1266 /* Get pending signal of THREAD as a host signal number, for detaching
1267 purposes. This is the signal the thread last stopped for, which we
1268 need to deliver to the thread when detaching, otherwise, it'd be
1272 get_detach_signal (struct lwp_info *lp)
1274 enum gdb_signal signo = GDB_SIGNAL_0;
1276 /* If we paused threads momentarily, we may have stored pending
1277 events in lp->status or lp->waitstatus (see stop_wait_callback),
1278 and GDB core hasn't seen any signal for those threads.
1279 Otherwise, the last signal reported to the core is found in the
1280 thread object's stop_signal.
1282 There's a corner case that isn't handled here at present. Only
1283 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1284 stop_signal make sense as a real signal to pass to the inferior.
1285 Some catchpoint related events, like
1286 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1287 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1288 those traps are debug API (ptrace in our case) related and
1289 induced; the inferior wouldn't see them if it wasn't being
1290 traced. Hence, we should never pass them to the inferior, even
1291 when set to pass state. Since this corner case isn't handled by
1292 infrun.c when proceeding with a signal, for consistency, neither
1293 do we handle it here (or elsewhere in the file we check for
1294 signal pass state). Normally SIGTRAP isn't set to pass state, so
1295 this is really a corner case. */
1297 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1298 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1299 else if (lp->status)
1300 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1303 struct thread_info *tp = find_thread_ptid (lp->ptid);
1305 if (target_is_non_stop_p () && !tp->executing)
1307 if (tp->suspend.waitstatus_pending_p)
1308 signo = tp->suspend.waitstatus.value.sig;
1310 signo = tp->suspend.stop_signal;
1312 else if (!target_is_non_stop_p ())
1314 struct target_waitstatus last;
1317 get_last_target_status (&last_ptid, &last);
1319 if (lp->ptid.lwp () == last_ptid.lwp ())
1320 signo = tp->suspend.stop_signal;
1324 if (signo == GDB_SIGNAL_0)
1326 if (debug_linux_nat)
1327 fprintf_unfiltered (gdb_stdlog,
1328 "GPT: lwp %s has no pending signal\n",
1329 target_pid_to_str (lp->ptid));
1331 else if (!signal_pass_state (signo))
1333 if (debug_linux_nat)
1334 fprintf_unfiltered (gdb_stdlog,
1335 "GPT: lwp %s had signal %s, "
1336 "but it is in no pass state\n",
1337 target_pid_to_str (lp->ptid),
1338 gdb_signal_to_string (signo));
1342 if (debug_linux_nat)
1343 fprintf_unfiltered (gdb_stdlog,
1344 "GPT: lwp %s has pending signal %s\n",
1345 target_pid_to_str (lp->ptid),
1346 gdb_signal_to_string (signo));
1348 return gdb_signal_to_host (signo);
1354 /* Detach from LP. If SIGNO_P is non-NULL, then it points to the
1355 signal number that should be passed to the LWP when detaching.
1356 Otherwise pass any pending signal the LWP may have, if any. */
1359 detach_one_lwp (struct lwp_info *lp, int *signo_p)
1361 int lwpid = lp->ptid.lwp ();
1364 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1366 if (debug_linux_nat && lp->status)
1367 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1368 strsignal (WSTOPSIG (lp->status)),
1369 target_pid_to_str (lp->ptid));
1371 /* If there is a pending SIGSTOP, get rid of it. */
1374 if (debug_linux_nat)
1375 fprintf_unfiltered (gdb_stdlog,
1376 "DC: Sending SIGCONT to %s\n",
1377 target_pid_to_str (lp->ptid));
1379 kill_lwp (lwpid, SIGCONT);
1383 if (signo_p == NULL)
1385 /* Pass on any pending signal for this LWP. */
1386 signo = get_detach_signal (lp);
1391 /* Preparing to resume may try to write registers, and fail if the
1392 lwp is zombie. If that happens, ignore the error. We'll handle
1393 it below, when detach fails with ESRCH. */
1396 linux_target->low_prepare_to_resume (lp);
1398 CATCH (ex, RETURN_MASK_ERROR)
1400 if (!check_ptrace_stopped_lwp_gone (lp))
1401 throw_exception (ex);
1405 if (ptrace (PTRACE_DETACH, lwpid, 0, signo) < 0)
1407 int save_errno = errno;
1409 /* We know the thread exists, so ESRCH must mean the lwp is
1410 zombie. This can happen if one of the already-detached
1411 threads exits the whole thread group. In that case we're
1412 still attached, and must reap the lwp. */
1413 if (save_errno == ESRCH)
1417 ret = my_waitpid (lwpid, &status, __WALL);
1420 warning (_("Couldn't reap LWP %d while detaching: %s"),
1421 lwpid, strerror (errno));
1423 else if (!WIFEXITED (status) && !WIFSIGNALED (status))
1425 warning (_("Reaping LWP %d while detaching "
1426 "returned unexpected status 0x%x"),
1432 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1433 safe_strerror (save_errno));
1436 else if (debug_linux_nat)
1438 fprintf_unfiltered (gdb_stdlog,
1439 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1440 target_pid_to_str (lp->ptid),
1444 delete_lwp (lp->ptid);
1448 detach_callback (struct lwp_info *lp, void *data)
1450 /* We don't actually detach from the thread group leader just yet.
1451 If the thread group exits, we must reap the zombie clone lwps
1452 before we're able to reap the leader. */
1453 if (lp->ptid.lwp () != lp->ptid.pid ())
1454 detach_one_lwp (lp, NULL);
1459 linux_nat_target::detach (inferior *inf, int from_tty)
1461 struct lwp_info *main_lwp;
1464 /* Don't unregister from the event loop, as there may be other
1465 inferiors running. */
1467 /* Stop all threads before detaching. ptrace requires that the
1468 thread is stopped to sucessfully detach. */
1469 iterate_over_lwps (ptid_t (pid), stop_callback, NULL);
1470 /* ... and wait until all of them have reported back that
1471 they're no longer running. */
1472 iterate_over_lwps (ptid_t (pid), stop_wait_callback, NULL);
1474 iterate_over_lwps (ptid_t (pid), detach_callback, NULL);
1476 /* Only the initial process should be left right now. */
1477 gdb_assert (num_lwps (pid) == 1);
1479 main_lwp = find_lwp_pid (ptid_t (pid));
1481 if (forks_exist_p ())
1483 /* Multi-fork case. The current inferior_ptid is being detached
1484 from, but there are other viable forks to debug. Detach from
1485 the current fork, and context-switch to the first
1487 linux_fork_detach (from_tty);
1491 target_announce_detach (from_tty);
1493 /* Pass on any pending signal for the last LWP. */
1494 int signo = get_detach_signal (main_lwp);
1496 detach_one_lwp (main_lwp, &signo);
1498 detach_success (inf);
1502 /* Resume execution of the inferior process. If STEP is nonzero,
1503 single-step it. If SIGNAL is nonzero, give it that signal. */
1506 linux_resume_one_lwp_throw (struct lwp_info *lp, int step,
1507 enum gdb_signal signo)
1511 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1512 We only presently need that if the LWP is stepped though (to
1513 handle the case of stepping a breakpoint instruction). */
1516 struct regcache *regcache = get_thread_regcache (lp->ptid);
1518 lp->stop_pc = regcache_read_pc (regcache);
1523 linux_target->low_prepare_to_resume (lp);
1524 linux_target->low_resume (lp->ptid, step, signo);
1526 /* Successfully resumed. Clear state that no longer makes sense,
1527 and mark the LWP as running. Must not do this before resuming
1528 otherwise if that fails other code will be confused. E.g., we'd
1529 later try to stop the LWP and hang forever waiting for a stop
1530 status. Note that we must not throw after this is cleared,
1531 otherwise handle_zombie_lwp_error would get confused. */
1534 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1535 registers_changed_ptid (lp->ptid);
1538 /* Called when we try to resume a stopped LWP and that errors out. If
1539 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1540 or about to become), discard the error, clear any pending status
1541 the LWP may have, and return true (we'll collect the exit status
1542 soon enough). Otherwise, return false. */
1545 check_ptrace_stopped_lwp_gone (struct lwp_info *lp)
1547 /* If we get an error after resuming the LWP successfully, we'd
1548 confuse !T state for the LWP being gone. */
1549 gdb_assert (lp->stopped);
1551 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1552 because even if ptrace failed with ESRCH, the tracee may be "not
1553 yet fully dead", but already refusing ptrace requests. In that
1554 case the tracee has 'R (Running)' state for a little bit
1555 (observed in Linux 3.18). See also the note on ESRCH in the
1556 ptrace(2) man page. Instead, check whether the LWP has any state
1557 other than ptrace-stopped. */
1559 /* Don't assume anything if /proc/PID/status can't be read. */
1560 if (linux_proc_pid_is_trace_stopped_nowarn (lp->ptid.lwp ()) == 0)
1562 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1564 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
1570 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1571 disappears while we try to resume it. */
1574 linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1578 linux_resume_one_lwp_throw (lp, step, signo);
1580 CATCH (ex, RETURN_MASK_ERROR)
1582 if (!check_ptrace_stopped_lwp_gone (lp))
1583 throw_exception (ex);
1591 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1595 struct inferior *inf = find_inferior_ptid (lp->ptid);
1597 if (inf->vfork_child != NULL)
1599 if (debug_linux_nat)
1600 fprintf_unfiltered (gdb_stdlog,
1601 "RC: Not resuming %s (vfork parent)\n",
1602 target_pid_to_str (lp->ptid));
1604 else if (!lwp_status_pending_p (lp))
1606 if (debug_linux_nat)
1607 fprintf_unfiltered (gdb_stdlog,
1608 "RC: Resuming sibling %s, %s, %s\n",
1609 target_pid_to_str (lp->ptid),
1610 (signo != GDB_SIGNAL_0
1611 ? strsignal (gdb_signal_to_host (signo))
1613 step ? "step" : "resume");
1615 linux_resume_one_lwp (lp, step, signo);
1619 if (debug_linux_nat)
1620 fprintf_unfiltered (gdb_stdlog,
1621 "RC: Not resuming sibling %s (has pending)\n",
1622 target_pid_to_str (lp->ptid));
1627 if (debug_linux_nat)
1628 fprintf_unfiltered (gdb_stdlog,
1629 "RC: Not resuming sibling %s (not stopped)\n",
1630 target_pid_to_str (lp->ptid));
1634 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1635 Resume LWP with the last stop signal, if it is in pass state. */
1638 linux_nat_resume_callback (struct lwp_info *lp, void *except)
1640 enum gdb_signal signo = GDB_SIGNAL_0;
1647 struct thread_info *thread;
1649 thread = find_thread_ptid (lp->ptid);
1652 signo = thread->suspend.stop_signal;
1653 thread->suspend.stop_signal = GDB_SIGNAL_0;
1657 resume_lwp (lp, 0, signo);
1662 resume_clear_callback (struct lwp_info *lp, void *data)
1665 lp->last_resume_kind = resume_stop;
1670 resume_set_callback (struct lwp_info *lp, void *data)
1673 lp->last_resume_kind = resume_continue;
1678 linux_nat_target::resume (ptid_t ptid, int step, enum gdb_signal signo)
1680 struct lwp_info *lp;
1683 if (debug_linux_nat)
1684 fprintf_unfiltered (gdb_stdlog,
1685 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1686 step ? "step" : "resume",
1687 target_pid_to_str (ptid),
1688 (signo != GDB_SIGNAL_0
1689 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1690 target_pid_to_str (inferior_ptid));
1692 /* A specific PTID means `step only this process id'. */
1693 resume_many = (ptid_equal (minus_one_ptid, ptid)
1696 /* Mark the lwps we're resuming as resumed. */
1697 iterate_over_lwps (ptid, resume_set_callback, NULL);
1699 /* See if it's the current inferior that should be handled
1702 lp = find_lwp_pid (inferior_ptid);
1704 lp = find_lwp_pid (ptid);
1705 gdb_assert (lp != NULL);
1707 /* Remember if we're stepping. */
1708 lp->last_resume_kind = step ? resume_step : resume_continue;
1710 /* If we have a pending wait status for this thread, there is no
1711 point in resuming the process. But first make sure that
1712 linux_nat_wait won't preemptively handle the event - we
1713 should never take this short-circuit if we are going to
1714 leave LP running, since we have skipped resuming all the
1715 other threads. This bit of code needs to be synchronized
1716 with linux_nat_wait. */
1718 if (lp->status && WIFSTOPPED (lp->status))
1721 && WSTOPSIG (lp->status)
1722 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1724 if (debug_linux_nat)
1725 fprintf_unfiltered (gdb_stdlog,
1726 "LLR: Not short circuiting for ignored "
1727 "status 0x%x\n", lp->status);
1729 /* FIXME: What should we do if we are supposed to continue
1730 this thread with a signal? */
1731 gdb_assert (signo == GDB_SIGNAL_0);
1732 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1737 if (lwp_status_pending_p (lp))
1739 /* FIXME: What should we do if we are supposed to continue
1740 this thread with a signal? */
1741 gdb_assert (signo == GDB_SIGNAL_0);
1743 if (debug_linux_nat)
1744 fprintf_unfiltered (gdb_stdlog,
1745 "LLR: Short circuiting for status 0x%x\n",
1748 if (target_can_async_p ())
1751 /* Tell the event loop we have something to process. */
1758 iterate_over_lwps (ptid, linux_nat_resume_callback, lp);
1760 if (debug_linux_nat)
1761 fprintf_unfiltered (gdb_stdlog,
1762 "LLR: %s %s, %s (resume event thread)\n",
1763 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1764 target_pid_to_str (lp->ptid),
1765 (signo != GDB_SIGNAL_0
1766 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1768 linux_resume_one_lwp (lp, step, signo);
1770 if (target_can_async_p ())
1774 /* Send a signal to an LWP. */
1777 kill_lwp (int lwpid, int signo)
1782 ret = syscall (__NR_tkill, lwpid, signo);
1783 if (errno == ENOSYS)
1785 /* If tkill fails, then we are not using nptl threads, a
1786 configuration we no longer support. */
1787 perror_with_name (("tkill"));
1792 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1793 event, check if the core is interested in it: if not, ignore the
1794 event, and keep waiting; otherwise, we need to toggle the LWP's
1795 syscall entry/exit status, since the ptrace event itself doesn't
1796 indicate it, and report the trap to higher layers. */
1799 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1801 struct target_waitstatus *ourstatus = &lp->waitstatus;
1802 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1803 thread_info *thread = find_thread_ptid (lp->ptid);
1804 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, thread);
1808 /* If we're stopping threads, there's a SIGSTOP pending, which
1809 makes it so that the LWP reports an immediate syscall return,
1810 followed by the SIGSTOP. Skip seeing that "return" using
1811 PTRACE_CONT directly, and let stop_wait_callback collect the
1812 SIGSTOP. Later when the thread is resumed, a new syscall
1813 entry event. If we didn't do this (and returned 0), we'd
1814 leave a syscall entry pending, and our caller, by using
1815 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1816 itself. Later, when the user re-resumes this LWP, we'd see
1817 another syscall entry event and we'd mistake it for a return.
1819 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1820 (leaving immediately with LWP->signalled set, without issuing
1821 a PTRACE_CONT), it would still be problematic to leave this
1822 syscall enter pending, as later when the thread is resumed,
1823 it would then see the same syscall exit mentioned above,
1824 followed by the delayed SIGSTOP, while the syscall didn't
1825 actually get to execute. It seems it would be even more
1826 confusing to the user. */
1828 if (debug_linux_nat)
1829 fprintf_unfiltered (gdb_stdlog,
1830 "LHST: ignoring syscall %d "
1831 "for LWP %ld (stopping threads), "
1832 "resuming with PTRACE_CONT for SIGSTOP\n",
1836 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1837 ptrace (PTRACE_CONT, lp->ptid.lwp (), 0, 0);
1842 /* Always update the entry/return state, even if this particular
1843 syscall isn't interesting to the core now. In async mode,
1844 the user could install a new catchpoint for this syscall
1845 between syscall enter/return, and we'll need to know to
1846 report a syscall return if that happens. */
1847 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1848 ? TARGET_WAITKIND_SYSCALL_RETURN
1849 : TARGET_WAITKIND_SYSCALL_ENTRY);
1851 if (catch_syscall_enabled ())
1853 if (catching_syscall_number (syscall_number))
1855 /* Alright, an event to report. */
1856 ourstatus->kind = lp->syscall_state;
1857 ourstatus->value.syscall_number = syscall_number;
1859 if (debug_linux_nat)
1860 fprintf_unfiltered (gdb_stdlog,
1861 "LHST: stopping for %s of syscall %d"
1864 == TARGET_WAITKIND_SYSCALL_ENTRY
1865 ? "entry" : "return",
1871 if (debug_linux_nat)
1872 fprintf_unfiltered (gdb_stdlog,
1873 "LHST: ignoring %s of syscall %d "
1875 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1876 ? "entry" : "return",
1882 /* If we had been syscall tracing, and hence used PT_SYSCALL
1883 before on this LWP, it could happen that the user removes all
1884 syscall catchpoints before we get to process this event.
1885 There are two noteworthy issues here:
1887 - When stopped at a syscall entry event, resuming with
1888 PT_STEP still resumes executing the syscall and reports a
1891 - Only PT_SYSCALL catches syscall enters. If we last
1892 single-stepped this thread, then this event can't be a
1893 syscall enter. If we last single-stepped this thread, this
1894 has to be a syscall exit.
1896 The points above mean that the next resume, be it PT_STEP or
1897 PT_CONTINUE, can not trigger a syscall trace event. */
1898 if (debug_linux_nat)
1899 fprintf_unfiltered (gdb_stdlog,
1900 "LHST: caught syscall event "
1901 "with no syscall catchpoints."
1902 " %d for LWP %ld, ignoring\n",
1905 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1908 /* The core isn't interested in this event. For efficiency, avoid
1909 stopping all threads only to have the core resume them all again.
1910 Since we're not stopping threads, if we're still syscall tracing
1911 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1912 subsequent syscall. Simply resume using the inf-ptrace layer,
1913 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1915 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
1919 /* Handle a GNU/Linux extended wait response. If we see a clone
1920 event, we need to add the new LWP to our list (and not report the
1921 trap to higher layers). This function returns non-zero if the
1922 event should be ignored and we should wait again. If STOPPING is
1923 true, the new LWP remains stopped, otherwise it is continued. */
1926 linux_handle_extended_wait (struct lwp_info *lp, int status)
1928 int pid = lp->ptid.lwp ();
1929 struct target_waitstatus *ourstatus = &lp->waitstatus;
1930 int event = linux_ptrace_get_extended_event (status);
1932 /* All extended events we currently use are mid-syscall. Only
1933 PTRACE_EVENT_STOP is delivered more like a signal-stop, but
1934 you have to be using PTRACE_SEIZE to get that. */
1935 lp->syscall_state = TARGET_WAITKIND_SYSCALL_ENTRY;
1937 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1938 || event == PTRACE_EVENT_CLONE)
1940 unsigned long new_pid;
1943 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
1945 /* If we haven't already seen the new PID stop, wait for it now. */
1946 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
1948 /* The new child has a pending SIGSTOP. We can't affect it until it
1949 hits the SIGSTOP, but we're already attached. */
1950 ret = my_waitpid (new_pid, &status, __WALL);
1952 perror_with_name (_("waiting for new child"));
1953 else if (ret != new_pid)
1954 internal_error (__FILE__, __LINE__,
1955 _("wait returned unexpected PID %d"), ret);
1956 else if (!WIFSTOPPED (status))
1957 internal_error (__FILE__, __LINE__,
1958 _("wait returned unexpected status 0x%x"), status);
1961 ourstatus->value.related_pid = ptid_t (new_pid, new_pid, 0);
1963 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
1965 /* The arch-specific native code may need to know about new
1966 forks even if those end up never mapped to an
1968 linux_target->low_new_fork (lp, new_pid);
1971 if (event == PTRACE_EVENT_FORK
1972 && linux_fork_checkpointing_p (lp->ptid.pid ()))
1974 /* Handle checkpointing by linux-fork.c here as a special
1975 case. We don't want the follow-fork-mode or 'catch fork'
1976 to interfere with this. */
1978 /* This won't actually modify the breakpoint list, but will
1979 physically remove the breakpoints from the child. */
1980 detach_breakpoints (ptid_t (new_pid, new_pid, 0));
1982 /* Retain child fork in ptrace (stopped) state. */
1983 if (!find_fork_pid (new_pid))
1986 /* Report as spurious, so that infrun doesn't want to follow
1987 this fork. We're actually doing an infcall in
1989 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
1991 /* Report the stop to the core. */
1995 if (event == PTRACE_EVENT_FORK)
1996 ourstatus->kind = TARGET_WAITKIND_FORKED;
1997 else if (event == PTRACE_EVENT_VFORK)
1998 ourstatus->kind = TARGET_WAITKIND_VFORKED;
1999 else if (event == PTRACE_EVENT_CLONE)
2001 struct lwp_info *new_lp;
2003 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2005 if (debug_linux_nat)
2006 fprintf_unfiltered (gdb_stdlog,
2007 "LHEW: Got clone event "
2008 "from LWP %d, new child is LWP %ld\n",
2011 new_lp = add_lwp (ptid_t (lp->ptid.pid (), new_pid, 0));
2012 new_lp->stopped = 1;
2013 new_lp->resumed = 1;
2015 /* If the thread_db layer is active, let it record the user
2016 level thread id and status, and add the thread to GDB's
2018 if (!thread_db_notice_clone (lp->ptid, new_lp->ptid))
2020 /* The process is not using thread_db. Add the LWP to
2022 target_post_attach (new_lp->ptid.lwp ());
2023 add_thread (new_lp->ptid);
2026 /* Even if we're stopping the thread for some reason
2027 internal to this module, from the perspective of infrun
2028 and the user/frontend, this new thread is running until
2029 it next reports a stop. */
2030 set_running (new_lp->ptid, 1);
2031 set_executing (new_lp->ptid, 1);
2033 if (WSTOPSIG (status) != SIGSTOP)
2035 /* This can happen if someone starts sending signals to
2036 the new thread before it gets a chance to run, which
2037 have a lower number than SIGSTOP (e.g. SIGUSR1).
2038 This is an unlikely case, and harder to handle for
2039 fork / vfork than for clone, so we do not try - but
2040 we handle it for clone events here. */
2042 new_lp->signalled = 1;
2044 /* We created NEW_LP so it cannot yet contain STATUS. */
2045 gdb_assert (new_lp->status == 0);
2047 /* Save the wait status to report later. */
2048 if (debug_linux_nat)
2049 fprintf_unfiltered (gdb_stdlog,
2050 "LHEW: waitpid of new LWP %ld, "
2051 "saving status %s\n",
2052 (long) new_lp->ptid.lwp (),
2053 status_to_str (status));
2054 new_lp->status = status;
2056 else if (report_thread_events)
2058 new_lp->waitstatus.kind = TARGET_WAITKIND_THREAD_CREATED;
2059 new_lp->status = status;
2068 if (event == PTRACE_EVENT_EXEC)
2070 if (debug_linux_nat)
2071 fprintf_unfiltered (gdb_stdlog,
2072 "LHEW: Got exec event from LWP %ld\n",
2075 ourstatus->kind = TARGET_WAITKIND_EXECD;
2076 ourstatus->value.execd_pathname
2077 = xstrdup (linux_proc_pid_to_exec_file (pid));
2079 /* The thread that execed must have been resumed, but, when a
2080 thread execs, it changes its tid to the tgid, and the old
2081 tgid thread might have not been resumed. */
2086 if (event == PTRACE_EVENT_VFORK_DONE)
2088 if (current_inferior ()->waiting_for_vfork_done)
2090 if (debug_linux_nat)
2091 fprintf_unfiltered (gdb_stdlog,
2092 "LHEW: Got expected PTRACE_EVENT_"
2093 "VFORK_DONE from LWP %ld: stopping\n",
2096 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2100 if (debug_linux_nat)
2101 fprintf_unfiltered (gdb_stdlog,
2102 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2103 "from LWP %ld: ignoring\n",
2108 internal_error (__FILE__, __LINE__,
2109 _("unknown ptrace event %d"), event);
2112 /* Suspend waiting for a signal. We're mostly interested in
2118 if (debug_linux_nat)
2119 fprintf_unfiltered (gdb_stdlog, "linux-nat: about to sigsuspend\n");
2120 sigsuspend (&suspend_mask);
2122 /* If the quit flag is set, it means that the user pressed Ctrl-C
2123 and we're debugging a process that is running on a separate
2124 terminal, so we must forward the Ctrl-C to the inferior. (If the
2125 inferior is sharing GDB's terminal, then the Ctrl-C reaches the
2126 inferior directly.) We must do this here because functions that
2127 need to block waiting for a signal loop forever until there's an
2128 event to report before returning back to the event loop. */
2129 if (!target_terminal::is_ours ())
2131 if (check_quit_flag ())
2132 target_pass_ctrlc ();
2136 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2140 wait_lwp (struct lwp_info *lp)
2144 int thread_dead = 0;
2147 gdb_assert (!lp->stopped);
2148 gdb_assert (lp->status == 0);
2150 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2151 block_child_signals (&prev_mask);
2155 pid = my_waitpid (lp->ptid.lwp (), &status, __WALL | WNOHANG);
2156 if (pid == -1 && errno == ECHILD)
2158 /* The thread has previously exited. We need to delete it
2159 now because if this was a non-leader thread execing, we
2160 won't get an exit event. See comments on exec events at
2161 the top of the file. */
2163 if (debug_linux_nat)
2164 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2165 target_pid_to_str (lp->ptid));
2170 /* Bugs 10970, 12702.
2171 Thread group leader may have exited in which case we'll lock up in
2172 waitpid if there are other threads, even if they are all zombies too.
2173 Basically, we're not supposed to use waitpid this way.
2174 tkill(pid,0) cannot be used here as it gets ESRCH for both
2175 for zombie and running processes.
2177 As a workaround, check if we're waiting for the thread group leader and
2178 if it's a zombie, and avoid calling waitpid if it is.
2180 This is racy, what if the tgl becomes a zombie right after we check?
2181 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2182 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2184 if (lp->ptid.pid () == lp->ptid.lwp ()
2185 && linux_proc_pid_is_zombie (lp->ptid.lwp ()))
2188 if (debug_linux_nat)
2189 fprintf_unfiltered (gdb_stdlog,
2190 "WL: Thread group leader %s vanished.\n",
2191 target_pid_to_str (lp->ptid));
2195 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2196 get invoked despite our caller had them intentionally blocked by
2197 block_child_signals. This is sensitive only to the loop of
2198 linux_nat_wait_1 and there if we get called my_waitpid gets called
2199 again before it gets to sigsuspend so we can safely let the handlers
2200 get executed here. */
2204 restore_child_signals_mask (&prev_mask);
2208 gdb_assert (pid == lp->ptid.lwp ());
2210 if (debug_linux_nat)
2212 fprintf_unfiltered (gdb_stdlog,
2213 "WL: waitpid %s received %s\n",
2214 target_pid_to_str (lp->ptid),
2215 status_to_str (status));
2218 /* Check if the thread has exited. */
2219 if (WIFEXITED (status) || WIFSIGNALED (status))
2221 if (report_thread_events
2222 || lp->ptid.pid () == lp->ptid.lwp ())
2224 if (debug_linux_nat)
2225 fprintf_unfiltered (gdb_stdlog, "WL: LWP %d exited.\n",
2228 /* If this is the leader exiting, it means the whole
2229 process is gone. Store the status to report to the
2230 core. Store it in lp->waitstatus, because lp->status
2231 would be ambiguous (W_EXITCODE(0,0) == 0). */
2232 store_waitstatus (&lp->waitstatus, status);
2237 if (debug_linux_nat)
2238 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2239 target_pid_to_str (lp->ptid));
2249 gdb_assert (WIFSTOPPED (status));
2252 if (lp->must_set_ptrace_flags)
2254 struct inferior *inf = find_inferior_pid (lp->ptid.pid ());
2255 int options = linux_nat_ptrace_options (inf->attach_flag);
2257 linux_enable_event_reporting (lp->ptid.lwp (), options);
2258 lp->must_set_ptrace_flags = 0;
2261 /* Handle GNU/Linux's syscall SIGTRAPs. */
2262 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2264 /* No longer need the sysgood bit. The ptrace event ends up
2265 recorded in lp->waitstatus if we care for it. We can carry
2266 on handling the event like a regular SIGTRAP from here
2268 status = W_STOPCODE (SIGTRAP);
2269 if (linux_handle_syscall_trap (lp, 1))
2270 return wait_lwp (lp);
2274 /* Almost all other ptrace-stops are known to be outside of system
2275 calls, with further exceptions in linux_handle_extended_wait. */
2276 lp->syscall_state = TARGET_WAITKIND_IGNORE;
2279 /* Handle GNU/Linux's extended waitstatus for trace events. */
2280 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
2281 && linux_is_extended_waitstatus (status))
2283 if (debug_linux_nat)
2284 fprintf_unfiltered (gdb_stdlog,
2285 "WL: Handling extended status 0x%06x\n",
2287 linux_handle_extended_wait (lp, status);
2294 /* Send a SIGSTOP to LP. */
2297 stop_callback (struct lwp_info *lp, void *data)
2299 if (!lp->stopped && !lp->signalled)
2303 if (debug_linux_nat)
2305 fprintf_unfiltered (gdb_stdlog,
2306 "SC: kill %s **<SIGSTOP>**\n",
2307 target_pid_to_str (lp->ptid));
2310 ret = kill_lwp (lp->ptid.lwp (), SIGSTOP);
2311 if (debug_linux_nat)
2313 fprintf_unfiltered (gdb_stdlog,
2314 "SC: lwp kill %d %s\n",
2316 errno ? safe_strerror (errno) : "ERRNO-OK");
2320 gdb_assert (lp->status == 0);
2326 /* Request a stop on LWP. */
2329 linux_stop_lwp (struct lwp_info *lwp)
2331 stop_callback (lwp, NULL);
2334 /* See linux-nat.h */
2337 linux_stop_and_wait_all_lwps (void)
2339 /* Stop all LWP's ... */
2340 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
2342 /* ... and wait until all of them have reported back that
2343 they're no longer running. */
2344 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
2347 /* See linux-nat.h */
2350 linux_unstop_all_lwps (void)
2352 iterate_over_lwps (minus_one_ptid,
2353 resume_stopped_resumed_lwps, &minus_one_ptid);
2356 /* Return non-zero if LWP PID has a pending SIGINT. */
2359 linux_nat_has_pending_sigint (int pid)
2361 sigset_t pending, blocked, ignored;
2363 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2365 if (sigismember (&pending, SIGINT)
2366 && !sigismember (&ignored, SIGINT))
2372 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2375 set_ignore_sigint (struct lwp_info *lp, void *data)
2377 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2378 flag to consume the next one. */
2379 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2380 && WSTOPSIG (lp->status) == SIGINT)
2383 lp->ignore_sigint = 1;
2388 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2389 This function is called after we know the LWP has stopped; if the LWP
2390 stopped before the expected SIGINT was delivered, then it will never have
2391 arrived. Also, if the signal was delivered to a shared queue and consumed
2392 by a different thread, it will never be delivered to this LWP. */
2395 maybe_clear_ignore_sigint (struct lwp_info *lp)
2397 if (!lp->ignore_sigint)
2400 if (!linux_nat_has_pending_sigint (lp->ptid.lwp ()))
2402 if (debug_linux_nat)
2403 fprintf_unfiltered (gdb_stdlog,
2404 "MCIS: Clearing bogus flag for %s\n",
2405 target_pid_to_str (lp->ptid));
2406 lp->ignore_sigint = 0;
2410 /* Fetch the possible triggered data watchpoint info and store it in
2413 On some archs, like x86, that use debug registers to set
2414 watchpoints, it's possible that the way to know which watched
2415 address trapped, is to check the register that is used to select
2416 which address to watch. Problem is, between setting the watchpoint
2417 and reading back which data address trapped, the user may change
2418 the set of watchpoints, and, as a consequence, GDB changes the
2419 debug registers in the inferior. To avoid reading back a stale
2420 stopped-data-address when that happens, we cache in LP the fact
2421 that a watchpoint trapped, and the corresponding data address, as
2422 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2423 registers meanwhile, we have the cached data we can rely on. */
2426 check_stopped_by_watchpoint (struct lwp_info *lp)
2428 scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
2429 inferior_ptid = lp->ptid;
2431 if (linux_target->low_stopped_by_watchpoint ())
2433 lp->stop_reason = TARGET_STOPPED_BY_WATCHPOINT;
2434 lp->stopped_data_address_p
2435 = linux_target->low_stopped_data_address (&lp->stopped_data_address);
2438 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2441 /* Returns true if the LWP had stopped for a watchpoint. */
2444 linux_nat_target::stopped_by_watchpoint ()
2446 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2448 gdb_assert (lp != NULL);
2450 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2454 linux_nat_target::stopped_data_address (CORE_ADDR *addr_p)
2456 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2458 gdb_assert (lp != NULL);
2460 *addr_p = lp->stopped_data_address;
2462 return lp->stopped_data_address_p;
2465 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2468 linux_nat_target::low_status_is_event (int status)
2470 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2473 /* Wait until LP is stopped. */
2476 stop_wait_callback (struct lwp_info *lp, void *data)
2478 struct inferior *inf = find_inferior_ptid (lp->ptid);
2480 /* If this is a vfork parent, bail out, it is not going to report
2481 any SIGSTOP until the vfork is done with. */
2482 if (inf->vfork_child != NULL)
2489 status = wait_lwp (lp);
2493 if (lp->ignore_sigint && WIFSTOPPED (status)
2494 && WSTOPSIG (status) == SIGINT)
2496 lp->ignore_sigint = 0;
2499 ptrace (PTRACE_CONT, lp->ptid.lwp (), 0, 0);
2501 if (debug_linux_nat)
2502 fprintf_unfiltered (gdb_stdlog,
2503 "PTRACE_CONT %s, 0, 0 (%s) "
2504 "(discarding SIGINT)\n",
2505 target_pid_to_str (lp->ptid),
2506 errno ? safe_strerror (errno) : "OK");
2508 return stop_wait_callback (lp, NULL);
2511 maybe_clear_ignore_sigint (lp);
2513 if (WSTOPSIG (status) != SIGSTOP)
2515 /* The thread was stopped with a signal other than SIGSTOP. */
2517 if (debug_linux_nat)
2518 fprintf_unfiltered (gdb_stdlog,
2519 "SWC: Pending event %s in %s\n",
2520 status_to_str ((int) status),
2521 target_pid_to_str (lp->ptid));
2523 /* Save the sigtrap event. */
2524 lp->status = status;
2525 gdb_assert (lp->signalled);
2526 save_stop_reason (lp);
2530 /* We caught the SIGSTOP that we intended to catch. */
2532 if (debug_linux_nat)
2533 fprintf_unfiltered (gdb_stdlog,
2534 "SWC: Expected SIGSTOP caught for %s.\n",
2535 target_pid_to_str (lp->ptid));
2539 /* If we are waiting for this stop so we can report the thread
2540 stopped then we need to record this status. Otherwise, we can
2541 now discard this stop event. */
2542 if (lp->last_resume_kind == resume_stop)
2544 lp->status = status;
2545 save_stop_reason (lp);
2553 /* Return non-zero if LP has a wait status pending. Discard the
2554 pending event and resume the LWP if the event that originally
2555 caused the stop became uninteresting. */
2558 status_callback (struct lwp_info *lp, void *data)
2560 /* Only report a pending wait status if we pretend that this has
2561 indeed been resumed. */
2565 if (!lwp_status_pending_p (lp))
2568 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
2569 || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2571 struct regcache *regcache = get_thread_regcache (lp->ptid);
2575 pc = regcache_read_pc (regcache);
2577 if (pc != lp->stop_pc)
2579 if (debug_linux_nat)
2580 fprintf_unfiltered (gdb_stdlog,
2581 "SC: PC of %s changed. was=%s, now=%s\n",
2582 target_pid_to_str (lp->ptid),
2583 paddress (target_gdbarch (), lp->stop_pc),
2584 paddress (target_gdbarch (), pc));
2588 #if !USE_SIGTRAP_SIGINFO
2589 else if (!breakpoint_inserted_here_p (regcache->aspace (), pc))
2591 if (debug_linux_nat)
2592 fprintf_unfiltered (gdb_stdlog,
2593 "SC: previous breakpoint of %s, at %s gone\n",
2594 target_pid_to_str (lp->ptid),
2595 paddress (target_gdbarch (), lp->stop_pc));
2603 if (debug_linux_nat)
2604 fprintf_unfiltered (gdb_stdlog,
2605 "SC: pending event of %s cancelled.\n",
2606 target_pid_to_str (lp->ptid));
2609 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
2617 /* Count the LWP's that have had events. */
2620 count_events_callback (struct lwp_info *lp, void *data)
2622 int *count = (int *) data;
2624 gdb_assert (count != NULL);
2626 /* Select only resumed LWPs that have an event pending. */
2627 if (lp->resumed && lwp_status_pending_p (lp))
2633 /* Select the LWP (if any) that is currently being single-stepped. */
2636 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2638 if (lp->last_resume_kind == resume_step
2645 /* Returns true if LP has a status pending. */
2648 lwp_status_pending_p (struct lwp_info *lp)
2650 /* We check for lp->waitstatus in addition to lp->status, because we
2651 can have pending process exits recorded in lp->status and
2652 W_EXITCODE(0,0) happens to be 0. */
2653 return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE;
2656 /* Select the Nth LWP that has had an event. */
2659 select_event_lwp_callback (struct lwp_info *lp, void *data)
2661 int *selector = (int *) data;
2663 gdb_assert (selector != NULL);
2665 /* Select only resumed LWPs that have an event pending. */
2666 if (lp->resumed && lwp_status_pending_p (lp))
2667 if ((*selector)-- == 0)
2673 /* Called when the LWP stopped for a signal/trap. If it stopped for a
2674 trap check what caused it (breakpoint, watchpoint, trace, etc.),
2675 and save the result in the LWP's stop_reason field. If it stopped
2676 for a breakpoint, decrement the PC if necessary on the lwp's
2680 save_stop_reason (struct lwp_info *lp)
2682 struct regcache *regcache;
2683 struct gdbarch *gdbarch;
2686 #if USE_SIGTRAP_SIGINFO
2690 gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
2691 gdb_assert (lp->status != 0);
2693 if (!linux_target->low_status_is_event (lp->status))
2696 regcache = get_thread_regcache (lp->ptid);
2697 gdbarch = regcache->arch ();
2699 pc = regcache_read_pc (regcache);
2700 sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch);
2702 #if USE_SIGTRAP_SIGINFO
2703 if (linux_nat_get_siginfo (lp->ptid, &siginfo))
2705 if (siginfo.si_signo == SIGTRAP)
2707 if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code)
2708 && GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
2710 /* The si_code is ambiguous on this arch -- check debug
2712 if (!check_stopped_by_watchpoint (lp))
2713 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2715 else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code))
2717 /* If we determine the LWP stopped for a SW breakpoint,
2718 trust it. Particularly don't check watchpoint
2719 registers, because at least on s390, we'd find
2720 stopped-by-watchpoint as long as there's a watchpoint
2722 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2724 else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
2726 /* This can indicate either a hardware breakpoint or
2727 hardware watchpoint. Check debug registers. */
2728 if (!check_stopped_by_watchpoint (lp))
2729 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2731 else if (siginfo.si_code == TRAP_TRACE)
2733 if (debug_linux_nat)
2734 fprintf_unfiltered (gdb_stdlog,
2735 "CSBB: %s stopped by trace\n",
2736 target_pid_to_str (lp->ptid));
2738 /* We may have single stepped an instruction that
2739 triggered a watchpoint. In that case, on some
2740 architectures (such as x86), instead of TRAP_HWBKPT,
2741 si_code indicates TRAP_TRACE, and we need to check
2742 the debug registers separately. */
2743 check_stopped_by_watchpoint (lp);
2748 if ((!lp->step || lp->stop_pc == sw_bp_pc)
2749 && software_breakpoint_inserted_here_p (regcache->aspace (),
2752 /* The LWP was either continued, or stepped a software
2753 breakpoint instruction. */
2754 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2757 if (hardware_breakpoint_inserted_here_p (regcache->aspace (), pc))
2758 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2760 if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON)
2761 check_stopped_by_watchpoint (lp);
2764 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT)
2766 if (debug_linux_nat)
2767 fprintf_unfiltered (gdb_stdlog,
2768 "CSBB: %s stopped by software breakpoint\n",
2769 target_pid_to_str (lp->ptid));
2771 /* Back up the PC if necessary. */
2773 regcache_write_pc (regcache, sw_bp_pc);
2775 /* Update this so we record the correct stop PC below. */
2778 else if (lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2780 if (debug_linux_nat)
2781 fprintf_unfiltered (gdb_stdlog,
2782 "CSBB: %s stopped by hardware breakpoint\n",
2783 target_pid_to_str (lp->ptid));
2785 else if (lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT)
2787 if (debug_linux_nat)
2788 fprintf_unfiltered (gdb_stdlog,
2789 "CSBB: %s stopped by hardware watchpoint\n",
2790 target_pid_to_str (lp->ptid));
2797 /* Returns true if the LWP had stopped for a software breakpoint. */
2800 linux_nat_target::stopped_by_sw_breakpoint ()
2802 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2804 gdb_assert (lp != NULL);
2806 return lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT;
2809 /* Implement the supports_stopped_by_sw_breakpoint method. */
2812 linux_nat_target::supports_stopped_by_sw_breakpoint ()
2814 return USE_SIGTRAP_SIGINFO;
2817 /* Returns true if the LWP had stopped for a hardware
2818 breakpoint/watchpoint. */
2821 linux_nat_target::stopped_by_hw_breakpoint ()
2823 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2825 gdb_assert (lp != NULL);
2827 return lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT;
2830 /* Implement the supports_stopped_by_hw_breakpoint method. */
2833 linux_nat_target::supports_stopped_by_hw_breakpoint ()
2835 return USE_SIGTRAP_SIGINFO;
2838 /* Select one LWP out of those that have events pending. */
2841 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2844 int random_selector;
2845 struct lwp_info *event_lp = NULL;
2847 /* Record the wait status for the original LWP. */
2848 (*orig_lp)->status = *status;
2850 /* In all-stop, give preference to the LWP that is being
2851 single-stepped. There will be at most one, and it will be the
2852 LWP that the core is most interested in. If we didn't do this,
2853 then we'd have to handle pending step SIGTRAPs somehow in case
2854 the core later continues the previously-stepped thread, as
2855 otherwise we'd report the pending SIGTRAP then, and the core, not
2856 having stepped the thread, wouldn't understand what the trap was
2857 for, and therefore would report it to the user as a random
2859 if (!target_is_non_stop_p ())
2861 event_lp = iterate_over_lwps (filter,
2862 select_singlestep_lwp_callback, NULL);
2863 if (event_lp != NULL)
2865 if (debug_linux_nat)
2866 fprintf_unfiltered (gdb_stdlog,
2867 "SEL: Select single-step %s\n",
2868 target_pid_to_str (event_lp->ptid));
2872 if (event_lp == NULL)
2874 /* Pick one at random, out of those which have had events. */
2876 /* First see how many events we have. */
2877 iterate_over_lwps (filter, count_events_callback, &num_events);
2878 gdb_assert (num_events > 0);
2880 /* Now randomly pick a LWP out of those that have had
2882 random_selector = (int)
2883 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2885 if (debug_linux_nat && num_events > 1)
2886 fprintf_unfiltered (gdb_stdlog,
2887 "SEL: Found %d events, selecting #%d\n",
2888 num_events, random_selector);
2890 event_lp = iterate_over_lwps (filter,
2891 select_event_lwp_callback,
2895 if (event_lp != NULL)
2897 /* Switch the event LWP. */
2898 *orig_lp = event_lp;
2899 *status = event_lp->status;
2902 /* Flush the wait status for the event LWP. */
2903 (*orig_lp)->status = 0;
2906 /* Return non-zero if LP has been resumed. */
2909 resumed_callback (struct lwp_info *lp, void *data)
2914 /* Check if we should go on and pass this event to common code.
2915 Return the affected lwp if we are, or NULL otherwise. */
2917 static struct lwp_info *
2918 linux_nat_filter_event (int lwpid, int status)
2920 struct lwp_info *lp;
2921 int event = linux_ptrace_get_extended_event (status);
2923 lp = find_lwp_pid (ptid_t (lwpid));
2925 /* Check for stop events reported by a process we didn't already
2926 know about - anything not already in our LWP list.
2928 If we're expecting to receive stopped processes after
2929 fork, vfork, and clone events, then we'll just add the
2930 new one to our list and go back to waiting for the event
2931 to be reported - the stopped process might be returned
2932 from waitpid before or after the event is.
2934 But note the case of a non-leader thread exec'ing after the
2935 leader having exited, and gone from our lists. The non-leader
2936 thread changes its tid to the tgid. */
2938 if (WIFSTOPPED (status) && lp == NULL
2939 && (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
2941 /* A multi-thread exec after we had seen the leader exiting. */
2942 if (debug_linux_nat)
2943 fprintf_unfiltered (gdb_stdlog,
2944 "LLW: Re-adding thread group leader LWP %d.\n",
2947 lp = add_lwp (ptid_t (lwpid, lwpid, 0));
2950 add_thread (lp->ptid);
2953 if (WIFSTOPPED (status) && !lp)
2955 if (debug_linux_nat)
2956 fprintf_unfiltered (gdb_stdlog,
2957 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2958 (long) lwpid, status_to_str (status));
2959 add_to_pid_list (&stopped_pids, lwpid, status);
2963 /* Make sure we don't report an event for the exit of an LWP not in
2964 our list, i.e. not part of the current process. This can happen
2965 if we detach from a program we originally forked and then it
2967 if (!WIFSTOPPED (status) && !lp)
2970 /* This LWP is stopped now. (And if dead, this prevents it from
2971 ever being continued.) */
2974 if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
2976 struct inferior *inf = find_inferior_pid (lp->ptid.pid ());
2977 int options = linux_nat_ptrace_options (inf->attach_flag);
2979 linux_enable_event_reporting (lp->ptid.lwp (), options);
2980 lp->must_set_ptrace_flags = 0;
2983 /* Handle GNU/Linux's syscall SIGTRAPs. */
2984 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2986 /* No longer need the sysgood bit. The ptrace event ends up
2987 recorded in lp->waitstatus if we care for it. We can carry
2988 on handling the event like a regular SIGTRAP from here
2990 status = W_STOPCODE (SIGTRAP);
2991 if (linux_handle_syscall_trap (lp, 0))
2996 /* Almost all other ptrace-stops are known to be outside of system
2997 calls, with further exceptions in linux_handle_extended_wait. */
2998 lp->syscall_state = TARGET_WAITKIND_IGNORE;
3001 /* Handle GNU/Linux's extended waitstatus for trace events. */
3002 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
3003 && linux_is_extended_waitstatus (status))
3005 if (debug_linux_nat)
3006 fprintf_unfiltered (gdb_stdlog,
3007 "LLW: Handling extended status 0x%06x\n",
3009 if (linux_handle_extended_wait (lp, status))
3013 /* Check if the thread has exited. */
3014 if (WIFEXITED (status) || WIFSIGNALED (status))
3016 if (!report_thread_events
3017 && num_lwps (lp->ptid.pid ()) > 1)
3019 if (debug_linux_nat)
3020 fprintf_unfiltered (gdb_stdlog,
3021 "LLW: %s exited.\n",
3022 target_pid_to_str (lp->ptid));
3024 /* If there is at least one more LWP, then the exit signal
3025 was not the end of the debugged application and should be
3031 /* Note that even if the leader was ptrace-stopped, it can still
3032 exit, if e.g., some other thread brings down the whole
3033 process (calls `exit'). So don't assert that the lwp is
3035 if (debug_linux_nat)
3036 fprintf_unfiltered (gdb_stdlog,
3037 "LWP %ld exited (resumed=%d)\n",
3038 lp->ptid.lwp (), lp->resumed);
3040 /* Dead LWP's aren't expected to reported a pending sigstop. */
3043 /* Store the pending event in the waitstatus, because
3044 W_EXITCODE(0,0) == 0. */
3045 store_waitstatus (&lp->waitstatus, status);
3049 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3050 an attempt to stop an LWP. */
3052 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3056 if (lp->last_resume_kind == resume_stop)
3058 if (debug_linux_nat)
3059 fprintf_unfiltered (gdb_stdlog,
3060 "LLW: resume_stop SIGSTOP caught for %s.\n",
3061 target_pid_to_str (lp->ptid));
3065 /* This is a delayed SIGSTOP. Filter out the event. */
3067 if (debug_linux_nat)
3068 fprintf_unfiltered (gdb_stdlog,
3069 "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
3071 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3072 target_pid_to_str (lp->ptid));
3074 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3075 gdb_assert (lp->resumed);
3080 /* Make sure we don't report a SIGINT that we have already displayed
3081 for another thread. */
3082 if (lp->ignore_sigint
3083 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3085 if (debug_linux_nat)
3086 fprintf_unfiltered (gdb_stdlog,
3087 "LLW: Delayed SIGINT caught for %s.\n",
3088 target_pid_to_str (lp->ptid));
3090 /* This is a delayed SIGINT. */
3091 lp->ignore_sigint = 0;
3093 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3094 if (debug_linux_nat)
3095 fprintf_unfiltered (gdb_stdlog,
3096 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3098 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3099 target_pid_to_str (lp->ptid));
3100 gdb_assert (lp->resumed);
3102 /* Discard the event. */
3106 /* Don't report signals that GDB isn't interested in, such as
3107 signals that are neither printed nor stopped upon. Stopping all
3108 threads can be a bit time-consuming so if we want decent
3109 performance with heavily multi-threaded programs, especially when
3110 they're using a high frequency timer, we'd better avoid it if we
3112 if (WIFSTOPPED (status))
3114 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3116 if (!target_is_non_stop_p ())
3118 /* Only do the below in all-stop, as we currently use SIGSTOP
3119 to implement target_stop (see linux_nat_stop) in
3121 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3123 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3124 forwarded to the entire process group, that is, all LWPs
3125 will receive it - unless they're using CLONE_THREAD to
3126 share signals. Since we only want to report it once, we
3127 mark it as ignored for all LWPs except this one. */
3128 iterate_over_lwps (ptid_t (lp->ptid.pid ()),
3129 set_ignore_sigint, NULL);
3130 lp->ignore_sigint = 0;
3133 maybe_clear_ignore_sigint (lp);
3136 /* When using hardware single-step, we need to report every signal.
3137 Otherwise, signals in pass_mask may be short-circuited
3138 except signals that might be caused by a breakpoint. */
3140 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status))
3141 && !linux_wstatus_maybe_breakpoint (status))
3143 linux_resume_one_lwp (lp, lp->step, signo);
3144 if (debug_linux_nat)
3145 fprintf_unfiltered (gdb_stdlog,
3146 "LLW: %s %s, %s (preempt 'handle')\n",
3148 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3149 target_pid_to_str (lp->ptid),
3150 (signo != GDB_SIGNAL_0
3151 ? strsignal (gdb_signal_to_host (signo))
3157 /* An interesting event. */
3159 lp->status = status;
3160 save_stop_reason (lp);
3164 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3165 their exits until all other threads in the group have exited. */
3168 check_zombie_leaders (void)
3170 struct inferior *inf;
3174 struct lwp_info *leader_lp;
3179 leader_lp = find_lwp_pid (ptid_t (inf->pid));
3180 if (leader_lp != NULL
3181 /* Check if there are other threads in the group, as we may
3182 have raced with the inferior simply exiting. */
3183 && num_lwps (inf->pid) > 1
3184 && linux_proc_pid_is_zombie (inf->pid))
3186 if (debug_linux_nat)
3187 fprintf_unfiltered (gdb_stdlog,
3188 "CZL: Thread group leader %d zombie "
3189 "(it exited, or another thread execd).\n",
3192 /* A leader zombie can mean one of two things:
3194 - It exited, and there's an exit status pending
3195 available, or only the leader exited (not the whole
3196 program). In the latter case, we can't waitpid the
3197 leader's exit status until all other threads are gone.
3199 - There are 3 or more threads in the group, and a thread
3200 other than the leader exec'd. See comments on exec
3201 events at the top of the file. We could try
3202 distinguishing the exit and exec cases, by waiting once
3203 more, and seeing if something comes out, but it doesn't
3204 sound useful. The previous leader _does_ go away, and
3205 we'll re-add the new one once we see the exec event
3206 (which is just the same as what would happen if the
3207 previous leader did exit voluntarily before some other
3210 if (debug_linux_nat)
3211 fprintf_unfiltered (gdb_stdlog,
3212 "CZL: Thread group leader %d vanished.\n",
3214 exit_lwp (leader_lp);
3219 /* Convenience function that is called when the kernel reports an exit
3220 event. This decides whether to report the event to GDB as a
3221 process exit event, a thread exit event, or to suppress the
3225 filter_exit_event (struct lwp_info *event_child,
3226 struct target_waitstatus *ourstatus)
3228 ptid_t ptid = event_child->ptid;
3230 if (num_lwps (ptid.pid ()) > 1)
3232 if (report_thread_events)
3233 ourstatus->kind = TARGET_WAITKIND_THREAD_EXITED;
3235 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3237 exit_lwp (event_child);
3244 linux_nat_wait_1 (ptid_t ptid, struct target_waitstatus *ourstatus,
3248 enum resume_kind last_resume_kind;
3249 struct lwp_info *lp;
3252 if (debug_linux_nat)
3253 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3255 /* The first time we get here after starting a new inferior, we may
3256 not have added it to the LWP list yet - this is the earliest
3257 moment at which we know its PID. */
3258 if (inferior_ptid.is_pid ())
3260 /* Upgrade the main thread's ptid. */
3261 thread_change_ptid (inferior_ptid,
3262 ptid_t (inferior_ptid.pid (),
3263 inferior_ptid.pid (), 0));
3265 lp = add_initial_lwp (inferior_ptid);
3269 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3270 block_child_signals (&prev_mask);
3272 /* First check if there is a LWP with a wait status pending. */
3273 lp = iterate_over_lwps (ptid, status_callback, NULL);
3276 if (debug_linux_nat)
3277 fprintf_unfiltered (gdb_stdlog,
3278 "LLW: Using pending wait status %s for %s.\n",
3279 status_to_str (lp->status),
3280 target_pid_to_str (lp->ptid));
3283 /* But if we don't find a pending event, we'll have to wait. Always
3284 pull all events out of the kernel. We'll randomly select an
3285 event LWP out of all that have events, to prevent starvation. */
3291 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3294 - If the thread group leader exits while other threads in the
3295 thread group still exist, waitpid(TGID, ...) hangs. That
3296 waitpid won't return an exit status until the other threads
3297 in the group are reapped.
3299 - When a non-leader thread execs, that thread just vanishes
3300 without reporting an exit (so we'd hang if we waited for it
3301 explicitly in that case). The exec event is reported to
3305 lwpid = my_waitpid (-1, &status, __WALL | WNOHANG);
3307 if (debug_linux_nat)
3308 fprintf_unfiltered (gdb_stdlog,
3309 "LNW: waitpid(-1, ...) returned %d, %s\n",
3310 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3314 if (debug_linux_nat)
3316 fprintf_unfiltered (gdb_stdlog,
3317 "LLW: waitpid %ld received %s\n",
3318 (long) lwpid, status_to_str (status));
3321 linux_nat_filter_event (lwpid, status);
3322 /* Retry until nothing comes out of waitpid. A single
3323 SIGCHLD can indicate more than one child stopped. */
3327 /* Now that we've pulled all events out of the kernel, resume
3328 LWPs that don't have an interesting event to report. */
3329 iterate_over_lwps (minus_one_ptid,
3330 resume_stopped_resumed_lwps, &minus_one_ptid);
3332 /* ... and find an LWP with a status to report to the core, if
3334 lp = iterate_over_lwps (ptid, status_callback, NULL);
3338 /* Check for zombie thread group leaders. Those can't be reaped
3339 until all other threads in the thread group are. */
3340 check_zombie_leaders ();
3342 /* If there are no resumed children left, bail. We'd be stuck
3343 forever in the sigsuspend call below otherwise. */
3344 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3346 if (debug_linux_nat)
3347 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3349 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3351 restore_child_signals_mask (&prev_mask);
3352 return minus_one_ptid;
3355 /* No interesting event to report to the core. */
3357 if (target_options & TARGET_WNOHANG)
3359 if (debug_linux_nat)
3360 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3362 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3363 restore_child_signals_mask (&prev_mask);
3364 return minus_one_ptid;
3367 /* We shouldn't end up here unless we want to try again. */
3368 gdb_assert (lp == NULL);
3370 /* Block until we get an event reported with SIGCHLD. */
3376 status = lp->status;
3379 if (!target_is_non_stop_p ())
3381 /* Now stop all other LWP's ... */
3382 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3384 /* ... and wait until all of them have reported back that
3385 they're no longer running. */
3386 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3389 /* If we're not waiting for a specific LWP, choose an event LWP from
3390 among those that have had events. Giving equal priority to all
3391 LWPs that have had events helps prevent starvation. */
3392 if (ptid_equal (ptid, minus_one_ptid) || ptid.is_pid ())
3393 select_event_lwp (ptid, &lp, &status);
3395 gdb_assert (lp != NULL);
3397 /* Now that we've selected our final event LWP, un-adjust its PC if
3398 it was a software breakpoint, and we can't reliably support the
3399 "stopped by software breakpoint" stop reason. */
3400 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
3401 && !USE_SIGTRAP_SIGINFO)
3403 struct regcache *regcache = get_thread_regcache (lp->ptid);
3404 struct gdbarch *gdbarch = regcache->arch ();
3405 int decr_pc = gdbarch_decr_pc_after_break (gdbarch);
3411 pc = regcache_read_pc (regcache);
3412 regcache_write_pc (regcache, pc + decr_pc);
3416 /* We'll need this to determine whether to report a SIGSTOP as
3417 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3419 last_resume_kind = lp->last_resume_kind;
3421 if (!target_is_non_stop_p ())
3423 /* In all-stop, from the core's perspective, all LWPs are now
3424 stopped until a new resume action is sent over. */
3425 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3429 resume_clear_callback (lp, NULL);
3432 if (linux_target->low_status_is_event (status))
3434 if (debug_linux_nat)
3435 fprintf_unfiltered (gdb_stdlog,
3436 "LLW: trap ptid is %s.\n",
3437 target_pid_to_str (lp->ptid));
3440 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3442 *ourstatus = lp->waitstatus;
3443 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3446 store_waitstatus (ourstatus, status);
3448 if (debug_linux_nat)
3449 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3451 restore_child_signals_mask (&prev_mask);
3453 if (last_resume_kind == resume_stop
3454 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3455 && WSTOPSIG (status) == SIGSTOP)
3457 /* A thread that has been requested to stop by GDB with
3458 target_stop, and it stopped cleanly, so report as SIG0. The
3459 use of SIGSTOP is an implementation detail. */
3460 ourstatus->value.sig = GDB_SIGNAL_0;
3463 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3464 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3467 lp->core = linux_common_core_of_thread (lp->ptid);
3469 if (ourstatus->kind == TARGET_WAITKIND_EXITED)
3470 return filter_exit_event (lp, ourstatus);
3475 /* Resume LWPs that are currently stopped without any pending status
3476 to report, but are resumed from the core's perspective. */
3479 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3481 ptid_t *wait_ptid_p = (ptid_t *) data;
3485 if (debug_linux_nat)
3486 fprintf_unfiltered (gdb_stdlog,
3487 "RSRL: NOT resuming LWP %s, not stopped\n",
3488 target_pid_to_str (lp->ptid));
3490 else if (!lp->resumed)
3492 if (debug_linux_nat)
3493 fprintf_unfiltered (gdb_stdlog,
3494 "RSRL: NOT resuming LWP %s, not resumed\n",
3495 target_pid_to_str (lp->ptid));
3497 else if (lwp_status_pending_p (lp))
3499 if (debug_linux_nat)
3500 fprintf_unfiltered (gdb_stdlog,
3501 "RSRL: NOT resuming LWP %s, has pending status\n",
3502 target_pid_to_str (lp->ptid));
3506 struct regcache *regcache = get_thread_regcache (lp->ptid);
3507 struct gdbarch *gdbarch = regcache->arch ();
3511 CORE_ADDR pc = regcache_read_pc (regcache);
3512 int leave_stopped = 0;
3514 /* Don't bother if there's a breakpoint at PC that we'd hit
3515 immediately, and we're not waiting for this LWP. */
3516 if (!ptid_match (lp->ptid, *wait_ptid_p))
3518 if (breakpoint_inserted_here_p (regcache->aspace (), pc))
3524 if (debug_linux_nat)
3525 fprintf_unfiltered (gdb_stdlog,
3526 "RSRL: resuming stopped-resumed LWP %s at "
3528 target_pid_to_str (lp->ptid),
3529 paddress (gdbarch, pc),
3532 linux_resume_one_lwp_throw (lp, lp->step, GDB_SIGNAL_0);
3535 CATCH (ex, RETURN_MASK_ERROR)
3537 if (!check_ptrace_stopped_lwp_gone (lp))
3538 throw_exception (ex);
3547 linux_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
3552 if (debug_linux_nat)
3554 char *options_string;
3556 options_string = target_options_to_string (target_options);
3557 fprintf_unfiltered (gdb_stdlog,
3558 "linux_nat_wait: [%s], [%s]\n",
3559 target_pid_to_str (ptid),
3561 xfree (options_string);
3564 /* Flush the async file first. */
3565 if (target_is_async_p ())
3566 async_file_flush ();
3568 /* Resume LWPs that are currently stopped without any pending status
3569 to report, but are resumed from the core's perspective. LWPs get
3570 in this state if we find them stopping at a time we're not
3571 interested in reporting the event (target_wait on a
3572 specific_process, for example, see linux_nat_wait_1), and
3573 meanwhile the event became uninteresting. Don't bother resuming
3574 LWPs we're not going to wait for if they'd stop immediately. */
3575 if (target_is_non_stop_p ())
3576 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3578 event_ptid = linux_nat_wait_1 (ptid, ourstatus, target_options);
3580 /* If we requested any event, and something came out, assume there
3581 may be more. If we requested a specific lwp or process, also
3582 assume there may be more. */
3583 if (target_is_async_p ()
3584 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3585 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3586 || !ptid_equal (ptid, minus_one_ptid)))
3595 kill_one_lwp (pid_t pid)
3597 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3600 kill_lwp (pid, SIGKILL);
3601 if (debug_linux_nat)
3603 int save_errno = errno;
3605 fprintf_unfiltered (gdb_stdlog,
3606 "KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid,
3607 save_errno ? safe_strerror (save_errno) : "OK");
3610 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3613 ptrace (PTRACE_KILL, pid, 0, 0);
3614 if (debug_linux_nat)
3616 int save_errno = errno;
3618 fprintf_unfiltered (gdb_stdlog,
3619 "KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid,
3620 save_errno ? safe_strerror (save_errno) : "OK");
3624 /* Wait for an LWP to die. */
3627 kill_wait_one_lwp (pid_t pid)
3631 /* We must make sure that there are no pending events (delayed
3632 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3633 program doesn't interfere with any following debugging session. */
3637 res = my_waitpid (pid, NULL, __WALL);
3638 if (res != (pid_t) -1)
3640 if (debug_linux_nat)
3641 fprintf_unfiltered (gdb_stdlog,
3642 "KWC: wait %ld received unknown.\n",
3644 /* The Linux kernel sometimes fails to kill a thread
3645 completely after PTRACE_KILL; that goes from the stop
3646 point in do_fork out to the one in get_signal_to_deliver
3647 and waits again. So kill it again. */
3653 gdb_assert (res == -1 && errno == ECHILD);
3656 /* Callback for iterate_over_lwps. */
3659 kill_callback (struct lwp_info *lp, void *data)
3661 kill_one_lwp (lp->ptid.lwp ());
3665 /* Callback for iterate_over_lwps. */
3668 kill_wait_callback (struct lwp_info *lp, void *data)
3670 kill_wait_one_lwp (lp->ptid.lwp ());
3674 /* Kill the fork children of any threads of inferior INF that are
3675 stopped at a fork event. */
3678 kill_unfollowed_fork_children (struct inferior *inf)
3680 struct thread_info *thread;
3682 ALL_NON_EXITED_THREADS (thread)
3683 if (thread->inf == inf)
3685 struct target_waitstatus *ws = &thread->pending_follow;
3687 if (ws->kind == TARGET_WAITKIND_FORKED
3688 || ws->kind == TARGET_WAITKIND_VFORKED)
3690 ptid_t child_ptid = ws->value.related_pid;
3691 int child_pid = child_ptid.pid ();
3692 int child_lwp = child_ptid.lwp ();
3694 kill_one_lwp (child_lwp);
3695 kill_wait_one_lwp (child_lwp);
3697 /* Let the arch-specific native code know this process is
3699 linux_target->low_forget_process (child_pid);
3705 linux_nat_target::kill ()
3707 /* If we're stopped while forking and we haven't followed yet,
3708 kill the other task. We need to do this first because the
3709 parent will be sleeping if this is a vfork. */
3710 kill_unfollowed_fork_children (current_inferior ());
3712 if (forks_exist_p ())
3713 linux_fork_killall ();
3716 ptid_t ptid = ptid_t (inferior_ptid.pid ());
3718 /* Stop all threads before killing them, since ptrace requires
3719 that the thread is stopped to sucessfully PTRACE_KILL. */
3720 iterate_over_lwps (ptid, stop_callback, NULL);
3721 /* ... and wait until all of them have reported back that
3722 they're no longer running. */
3723 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3725 /* Kill all LWP's ... */
3726 iterate_over_lwps (ptid, kill_callback, NULL);
3728 /* ... and wait until we've flushed all events. */
3729 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3732 target_mourn_inferior (inferior_ptid);
3736 linux_nat_target::mourn_inferior ()
3738 int pid = inferior_ptid.pid ();
3740 purge_lwp_list (pid);
3742 if (! forks_exist_p ())
3743 /* Normal case, no other forks available. */
3744 inf_ptrace_target::mourn_inferior ();
3746 /* Multi-fork case. The current inferior_ptid has exited, but
3747 there are other viable forks to debug. Delete the exiting
3748 one and context-switch to the first available. */
3749 linux_fork_mourn_inferior ();
3751 /* Let the arch-specific native code know this process is gone. */
3752 linux_target->low_forget_process (pid);
3755 /* Convert a native/host siginfo object, into/from the siginfo in the
3756 layout of the inferiors' architecture. */
3759 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3761 /* If the low target didn't do anything, then just do a straight
3763 if (!linux_target->low_siginfo_fixup (siginfo, inf_siginfo, direction))
3766 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3768 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3772 static enum target_xfer_status
3773 linux_xfer_siginfo (enum target_object object,
3774 const char *annex, gdb_byte *readbuf,
3775 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3776 ULONGEST *xfered_len)
3780 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3782 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3783 gdb_assert (readbuf || writebuf);
3785 pid = inferior_ptid.lwp ();
3787 pid = inferior_ptid.pid ();
3789 if (offset > sizeof (siginfo))
3790 return TARGET_XFER_E_IO;
3793 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3795 return TARGET_XFER_E_IO;
3797 /* When GDB is built as a 64-bit application, ptrace writes into
3798 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3799 inferior with a 64-bit GDB should look the same as debugging it
3800 with a 32-bit GDB, we need to convert it. GDB core always sees
3801 the converted layout, so any read/write will have to be done
3803 siginfo_fixup (&siginfo, inf_siginfo, 0);
3805 if (offset + len > sizeof (siginfo))
3806 len = sizeof (siginfo) - offset;
3808 if (readbuf != NULL)
3809 memcpy (readbuf, inf_siginfo + offset, len);
3812 memcpy (inf_siginfo + offset, writebuf, len);
3814 /* Convert back to ptrace layout before flushing it out. */
3815 siginfo_fixup (&siginfo, inf_siginfo, 1);
3818 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3820 return TARGET_XFER_E_IO;
3824 return TARGET_XFER_OK;
3827 static enum target_xfer_status
3828 linux_nat_xfer_osdata (enum target_object object,
3829 const char *annex, gdb_byte *readbuf,
3830 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3831 ULONGEST *xfered_len);
3833 static enum target_xfer_status
3834 linux_proc_xfer_spu (enum target_object object,
3835 const char *annex, gdb_byte *readbuf,
3836 const gdb_byte *writebuf,
3837 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len);
3839 static enum target_xfer_status
3840 linux_proc_xfer_partial (enum target_object object,
3841 const char *annex, gdb_byte *readbuf,
3842 const gdb_byte *writebuf,
3843 ULONGEST offset, LONGEST len, ULONGEST *xfered_len);
3845 enum target_xfer_status
3846 linux_nat_target::xfer_partial (enum target_object object,
3847 const char *annex, gdb_byte *readbuf,
3848 const gdb_byte *writebuf,
3849 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3851 enum target_xfer_status xfer;
3853 if (object == TARGET_OBJECT_SIGNAL_INFO)
3854 return linux_xfer_siginfo (object, annex, readbuf, writebuf,
3855 offset, len, xfered_len);
3857 /* The target is connected but no live inferior is selected. Pass
3858 this request down to a lower stratum (e.g., the executable
3860 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3861 return TARGET_XFER_EOF;
3863 if (object == TARGET_OBJECT_AUXV)
3864 return memory_xfer_auxv (this, object, annex, readbuf, writebuf,
3865 offset, len, xfered_len);
3867 if (object == TARGET_OBJECT_OSDATA)
3868 return linux_nat_xfer_osdata (object, annex, readbuf, writebuf,
3869 offset, len, xfered_len);
3871 if (object == TARGET_OBJECT_SPU)
3872 return linux_proc_xfer_spu (object, annex, readbuf, writebuf,
3873 offset, len, xfered_len);
3875 /* GDB calculates all addresses in the largest possible address
3877 The address width must be masked before its final use - either by
3878 linux_proc_xfer_partial or inf_ptrace_target::xfer_partial.
3880 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
3882 if (object == TARGET_OBJECT_MEMORY)
3884 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
3886 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
3887 offset &= ((ULONGEST) 1 << addr_bit) - 1;
3890 xfer = linux_proc_xfer_partial (object, annex, readbuf, writebuf,
3891 offset, len, xfered_len);
3892 if (xfer != TARGET_XFER_EOF)
3895 return inf_ptrace_target::xfer_partial (object, annex, readbuf, writebuf,
3896 offset, len, xfered_len);
3900 linux_nat_target::thread_alive (ptid_t ptid)
3902 /* As long as a PTID is in lwp list, consider it alive. */
3903 return find_lwp_pid (ptid) != NULL;
3906 /* Implement the to_update_thread_list target method for this
3910 linux_nat_target::update_thread_list ()
3912 struct lwp_info *lwp;
3914 /* We add/delete threads from the list as clone/exit events are
3915 processed, so just try deleting exited threads still in the
3917 delete_exited_threads ();
3919 /* Update the processor core that each lwp/thread was last seen
3923 /* Avoid accessing /proc if the thread hasn't run since we last
3924 time we fetched the thread's core. Accessing /proc becomes
3925 noticeably expensive when we have thousands of LWPs. */
3926 if (lwp->core == -1)
3927 lwp->core = linux_common_core_of_thread (lwp->ptid);
3932 linux_nat_target::pid_to_str (ptid_t ptid)
3934 static char buf[64];
3936 if (ptid_lwp_p (ptid)
3937 && (ptid.pid () != ptid.lwp ()
3938 || num_lwps (ptid.pid ()) > 1))
3940 snprintf (buf, sizeof (buf), "LWP %ld", ptid.lwp ());
3944 return normal_pid_to_str (ptid);
3948 linux_nat_target::thread_name (struct thread_info *thr)
3950 return linux_proc_tid_get_name (thr->ptid);
3953 /* Accepts an integer PID; Returns a string representing a file that
3954 can be opened to get the symbols for the child process. */
3957 linux_nat_target::pid_to_exec_file (int pid)
3959 return linux_proc_pid_to_exec_file (pid);
3962 /* Implement the to_xfer_partial target method using /proc/<pid>/mem.
3963 Because we can use a single read/write call, this can be much more
3964 efficient than banging away at PTRACE_PEEKTEXT. */
3966 static enum target_xfer_status
3967 linux_proc_xfer_partial (enum target_object object,
3968 const char *annex, gdb_byte *readbuf,
3969 const gdb_byte *writebuf,
3970 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
3976 if (object != TARGET_OBJECT_MEMORY)
3977 return TARGET_XFER_EOF;
3979 /* Don't bother for one word. */
3980 if (len < 3 * sizeof (long))
3981 return TARGET_XFER_EOF;
3983 /* We could keep this file open and cache it - possibly one per
3984 thread. That requires some juggling, but is even faster. */
3985 xsnprintf (filename, sizeof filename, "/proc/%ld/mem",
3986 inferior_ptid.lwp ());
3987 fd = gdb_open_cloexec (filename, ((readbuf ? O_RDONLY : O_WRONLY)
3990 return TARGET_XFER_EOF;
3992 /* Use pread64/pwrite64 if available, since they save a syscall and can
3993 handle 64-bit offsets even on 32-bit platforms (for instance, SPARC
3994 debugging a SPARC64 application). */
3996 ret = (readbuf ? pread64 (fd, readbuf, len, offset)
3997 : pwrite64 (fd, writebuf, len, offset));
3999 ret = lseek (fd, offset, SEEK_SET);
4001 ret = (readbuf ? read (fd, readbuf, len)
4002 : write (fd, writebuf, len));
4007 if (ret == -1 || ret == 0)
4008 return TARGET_XFER_EOF;
4012 return TARGET_XFER_OK;
4017 /* Enumerate spufs IDs for process PID. */
4019 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
4021 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4023 LONGEST written = 0;
4026 struct dirent *entry;
4028 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4029 dir = opendir (path);
4034 while ((entry = readdir (dir)) != NULL)
4040 fd = atoi (entry->d_name);
4044 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4045 if (stat (path, &st) != 0)
4047 if (!S_ISDIR (st.st_mode))
4050 if (statfs (path, &stfs) != 0)
4052 if (stfs.f_type != SPUFS_MAGIC)
4055 if (pos >= offset && pos + 4 <= offset + len)
4057 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4067 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4068 object type, using the /proc file system. */
4070 static enum target_xfer_status
4071 linux_proc_xfer_spu (enum target_object object,
4072 const char *annex, gdb_byte *readbuf,
4073 const gdb_byte *writebuf,
4074 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4079 int pid = inferior_ptid.lwp ();
4084 return TARGET_XFER_E_IO;
4087 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4090 return TARGET_XFER_E_IO;
4092 return TARGET_XFER_EOF;
4095 *xfered_len = (ULONGEST) l;
4096 return TARGET_XFER_OK;
4101 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4102 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4104 return TARGET_XFER_E_IO;
4107 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4110 return TARGET_XFER_EOF;
4114 ret = write (fd, writebuf, (size_t) len);
4116 ret = read (fd, readbuf, (size_t) len);
4121 return TARGET_XFER_E_IO;
4123 return TARGET_XFER_EOF;
4126 *xfered_len = (ULONGEST) ret;
4127 return TARGET_XFER_OK;
4132 /* Parse LINE as a signal set and add its set bits to SIGS. */
4135 add_line_to_sigset (const char *line, sigset_t *sigs)
4137 int len = strlen (line) - 1;
4141 if (line[len] != '\n')
4142 error (_("Could not parse signal set: %s"), line);
4150 if (*p >= '0' && *p <= '9')
4152 else if (*p >= 'a' && *p <= 'f')
4153 digit = *p - 'a' + 10;
4155 error (_("Could not parse signal set: %s"), line);
4160 sigaddset (sigs, signum + 1);
4162 sigaddset (sigs, signum + 2);
4164 sigaddset (sigs, signum + 3);
4166 sigaddset (sigs, signum + 4);
4172 /* Find process PID's pending signals from /proc/pid/status and set
4176 linux_proc_pending_signals (int pid, sigset_t *pending,
4177 sigset_t *blocked, sigset_t *ignored)
4179 char buffer[PATH_MAX], fname[PATH_MAX];
4181 sigemptyset (pending);
4182 sigemptyset (blocked);
4183 sigemptyset (ignored);
4184 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4185 gdb_file_up procfile = gdb_fopen_cloexec (fname, "r");
4186 if (procfile == NULL)
4187 error (_("Could not open %s"), fname);
4189 while (fgets (buffer, PATH_MAX, procfile.get ()) != NULL)
4191 /* Normal queued signals are on the SigPnd line in the status
4192 file. However, 2.6 kernels also have a "shared" pending
4193 queue for delivering signals to a thread group, so check for
4196 Unfortunately some Red Hat kernels include the shared pending
4197 queue but not the ShdPnd status field. */
4199 if (startswith (buffer, "SigPnd:\t"))
4200 add_line_to_sigset (buffer + 8, pending);
4201 else if (startswith (buffer, "ShdPnd:\t"))
4202 add_line_to_sigset (buffer + 8, pending);
4203 else if (startswith (buffer, "SigBlk:\t"))
4204 add_line_to_sigset (buffer + 8, blocked);
4205 else if (startswith (buffer, "SigIgn:\t"))
4206 add_line_to_sigset (buffer + 8, ignored);
4210 static enum target_xfer_status
4211 linux_nat_xfer_osdata (enum target_object object,
4212 const char *annex, gdb_byte *readbuf,
4213 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4214 ULONGEST *xfered_len)
4216 gdb_assert (object == TARGET_OBJECT_OSDATA);
4218 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4219 if (*xfered_len == 0)
4220 return TARGET_XFER_EOF;
4222 return TARGET_XFER_OK;
4226 cleanup_target_stop (void *arg)
4228 ptid_t *ptid = (ptid_t *) arg;
4230 gdb_assert (arg != NULL);
4233 target_continue_no_signal (*ptid);
4236 std::vector<static_tracepoint_marker>
4237 linux_nat_target::static_tracepoint_markers_by_strid (const char *strid)
4239 char s[IPA_CMD_BUF_SIZE];
4240 struct cleanup *old_chain;
4241 int pid = inferior_ptid.pid ();
4242 std::vector<static_tracepoint_marker> markers;
4244 ptid_t ptid = ptid_t (pid, 0, 0);
4245 static_tracepoint_marker marker;
4250 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4251 s[sizeof ("qTfSTM")] = 0;
4253 agent_run_command (pid, s, strlen (s) + 1);
4255 old_chain = make_cleanup (cleanup_target_stop, &ptid);
4261 parse_static_tracepoint_marker_definition (p, &p, &marker);
4263 if (strid == NULL || marker.str_id == strid)
4264 markers.push_back (std::move (marker));
4266 while (*p++ == ','); /* comma-separated list */
4268 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4269 s[sizeof ("qTsSTM")] = 0;
4270 agent_run_command (pid, s, strlen (s) + 1);
4274 do_cleanups (old_chain);
4279 /* target_is_async_p implementation. */
4282 linux_nat_target::is_async_p ()
4284 return linux_is_async_p ();
4287 /* target_can_async_p implementation. */
4290 linux_nat_target::can_async_p ()
4292 /* We're always async, unless the user explicitly prevented it with the
4293 "maint set target-async" command. */
4294 return target_async_permitted;
4298 linux_nat_target::supports_non_stop ()
4303 /* to_always_non_stop_p implementation. */
4306 linux_nat_target::always_non_stop_p ()
4311 /* True if we want to support multi-process. To be removed when GDB
4312 supports multi-exec. */
4314 int linux_multi_process = 1;
4317 linux_nat_target::supports_multi_process ()
4319 return linux_multi_process;
4323 linux_nat_target::supports_disable_randomization ()
4325 #ifdef HAVE_PERSONALITY
4332 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4333 so we notice when any child changes state, and notify the
4334 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4335 above to wait for the arrival of a SIGCHLD. */
4338 sigchld_handler (int signo)
4340 int old_errno = errno;
4342 if (debug_linux_nat)
4343 ui_file_write_async_safe (gdb_stdlog,
4344 "sigchld\n", sizeof ("sigchld\n") - 1);
4346 if (signo == SIGCHLD
4347 && linux_nat_event_pipe[0] != -1)
4348 async_file_mark (); /* Let the event loop know that there are
4349 events to handle. */
4354 /* Callback registered with the target events file descriptor. */
4357 handle_target_event (int error, gdb_client_data client_data)
4359 inferior_event_handler (INF_REG_EVENT, NULL);
4362 /* Create/destroy the target events pipe. Returns previous state. */
4365 linux_async_pipe (int enable)
4367 int previous = linux_is_async_p ();
4369 if (previous != enable)
4373 /* Block child signals while we create/destroy the pipe, as
4374 their handler writes to it. */
4375 block_child_signals (&prev_mask);
4379 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4380 internal_error (__FILE__, __LINE__,
4381 "creating event pipe failed.");
4383 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4384 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4388 close (linux_nat_event_pipe[0]);
4389 close (linux_nat_event_pipe[1]);
4390 linux_nat_event_pipe[0] = -1;
4391 linux_nat_event_pipe[1] = -1;
4394 restore_child_signals_mask (&prev_mask);
4400 /* target_async implementation. */
4403 linux_nat_target::async (int enable)
4407 if (!linux_async_pipe (1))
4409 add_file_handler (linux_nat_event_pipe[0],
4410 handle_target_event, NULL);
4411 /* There may be pending events to handle. Tell the event loop
4418 delete_file_handler (linux_nat_event_pipe[0]);
4419 linux_async_pipe (0);
4424 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4428 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4432 if (debug_linux_nat)
4433 fprintf_unfiltered (gdb_stdlog,
4434 "LNSL: running -> suspending %s\n",
4435 target_pid_to_str (lwp->ptid));
4438 if (lwp->last_resume_kind == resume_stop)
4440 if (debug_linux_nat)
4441 fprintf_unfiltered (gdb_stdlog,
4442 "linux-nat: already stopping LWP %ld at "
4448 stop_callback (lwp, NULL);
4449 lwp->last_resume_kind = resume_stop;
4453 /* Already known to be stopped; do nothing. */
4455 if (debug_linux_nat)
4457 if (find_thread_ptid (lwp->ptid)->stop_requested)
4458 fprintf_unfiltered (gdb_stdlog,
4459 "LNSL: already stopped/stop_requested %s\n",
4460 target_pid_to_str (lwp->ptid));
4462 fprintf_unfiltered (gdb_stdlog,
4463 "LNSL: already stopped/no "
4464 "stop_requested yet %s\n",
4465 target_pid_to_str (lwp->ptid));
4472 linux_nat_target::stop (ptid_t ptid)
4474 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4478 linux_nat_target::close ()
4480 /* Unregister from the event loop. */
4484 inf_ptrace_target::close ();
4487 /* When requests are passed down from the linux-nat layer to the
4488 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4489 used. The address space pointer is stored in the inferior object,
4490 but the common code that is passed such ptid can't tell whether
4491 lwpid is a "main" process id or not (it assumes so). We reverse
4492 look up the "main" process id from the lwp here. */
4494 struct address_space *
4495 linux_nat_target::thread_address_space (ptid_t ptid)
4497 struct lwp_info *lwp;
4498 struct inferior *inf;
4501 if (ptid.lwp () == 0)
4503 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4505 lwp = find_lwp_pid (ptid);
4506 pid = lwp->ptid.pid ();
4510 /* A (pid,lwpid,0) ptid. */
4514 inf = find_inferior_pid (pid);
4515 gdb_assert (inf != NULL);
4519 /* Return the cached value of the processor core for thread PTID. */
4522 linux_nat_target::core_of_thread (ptid_t ptid)
4524 struct lwp_info *info = find_lwp_pid (ptid);
4531 /* Implementation of to_filesystem_is_local. */
4534 linux_nat_target::filesystem_is_local ()
4536 struct inferior *inf = current_inferior ();
4538 if (inf->fake_pid_p || inf->pid == 0)
4541 return linux_ns_same (inf->pid, LINUX_NS_MNT);
4544 /* Convert the INF argument passed to a to_fileio_* method
4545 to a process ID suitable for passing to its corresponding
4546 linux_mntns_* function. If INF is non-NULL then the
4547 caller is requesting the filesystem seen by INF. If INF
4548 is NULL then the caller is requesting the filesystem seen
4549 by the GDB. We fall back to GDB's filesystem in the case
4550 that INF is non-NULL but its PID is unknown. */
4553 linux_nat_fileio_pid_of (struct inferior *inf)
4555 if (inf == NULL || inf->fake_pid_p || inf->pid == 0)
4561 /* Implementation of to_fileio_open. */
4564 linux_nat_target::fileio_open (struct inferior *inf, const char *filename,
4565 int flags, int mode, int warn_if_slow,
4572 if (fileio_to_host_openflags (flags, &nat_flags) == -1
4573 || fileio_to_host_mode (mode, &nat_mode) == -1)
4575 *target_errno = FILEIO_EINVAL;
4579 fd = linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf),
4580 filename, nat_flags, nat_mode);
4582 *target_errno = host_to_fileio_error (errno);
4587 /* Implementation of to_fileio_readlink. */
4589 gdb::optional<std::string>
4590 linux_nat_target::fileio_readlink (struct inferior *inf, const char *filename,
4596 len = linux_mntns_readlink (linux_nat_fileio_pid_of (inf),
4597 filename, buf, sizeof (buf));
4600 *target_errno = host_to_fileio_error (errno);
4604 return std::string (buf, len);
4607 /* Implementation of to_fileio_unlink. */
4610 linux_nat_target::fileio_unlink (struct inferior *inf, const char *filename,
4615 ret = linux_mntns_unlink (linux_nat_fileio_pid_of (inf),
4618 *target_errno = host_to_fileio_error (errno);
4623 /* Implementation of the to_thread_events method. */
4626 linux_nat_target::thread_events (int enable)
4628 report_thread_events = enable;
4631 linux_nat_target::linux_nat_target ()
4633 /* We don't change the stratum; this target will sit at
4634 process_stratum and thread_db will set at thread_stratum. This
4635 is a little strange, since this is a multi-threaded-capable
4636 target, but we want to be on the stack below thread_db, and we
4637 also want to be used for single-threaded processes. */
4640 /* See linux-nat.h. */
4643 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4652 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4655 memset (siginfo, 0, sizeof (*siginfo));
4661 /* See nat/linux-nat.h. */
4664 current_lwp_ptid (void)
4666 gdb_assert (ptid_lwp_p (inferior_ptid));
4667 return inferior_ptid;
4671 _initialize_linux_nat (void)
4673 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4674 &debug_linux_nat, _("\
4675 Set debugging of GNU/Linux lwp module."), _("\
4676 Show debugging of GNU/Linux lwp module."), _("\
4677 Enables printf debugging output."),
4679 show_debug_linux_nat,
4680 &setdebuglist, &showdebuglist);
4682 add_setshow_boolean_cmd ("linux-namespaces", class_maintenance,
4683 &debug_linux_namespaces, _("\
4684 Set debugging of GNU/Linux namespaces module."), _("\
4685 Show debugging of GNU/Linux namespaces module."), _("\
4686 Enables printf debugging output."),
4689 &setdebuglist, &showdebuglist);
4691 /* Save this mask as the default. */
4692 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4694 /* Install a SIGCHLD handler. */
4695 sigchld_action.sa_handler = sigchld_handler;
4696 sigemptyset (&sigchld_action.sa_mask);
4697 sigchld_action.sa_flags = SA_RESTART;
4699 /* Make it the default. */
4700 sigaction (SIGCHLD, &sigchld_action, NULL);
4702 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4703 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
4704 sigdelset (&suspend_mask, SIGCHLD);
4706 sigemptyset (&blocked_mask);
4708 lwp_lwpid_htab_create ();
4712 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4713 the GNU/Linux Threads library and therefore doesn't really belong
4716 /* Return the set of signals used by the threads library in *SET. */
4719 lin_thread_get_thread_signals (sigset_t *set)
4723 /* NPTL reserves the first two RT signals, but does not provide any
4724 way for the debugger to query the signal numbers - fortunately
4725 they don't change. */
4726 sigaddset (set, __SIGRTMIN);
4727 sigaddset (set, __SIGRTMIN + 1);