1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2019 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"
69 #include "common/scope-exit.h"
72 #define SPUFS_MAGIC 0x23c9b64e
75 /* This comment documents high-level logic of this file.
77 Waiting for events in sync mode
78 ===============================
80 When waiting for an event in a specific thread, we just use waitpid,
81 passing the specific pid, and not passing WNOHANG.
83 When waiting for an event in all threads, waitpid is not quite good:
85 - If the thread group leader exits while other threads in the thread
86 group still exist, waitpid(TGID, ...) hangs. That waitpid won't
87 return an exit status until the other threads in the group are
90 - When a non-leader thread execs, that thread just vanishes without
91 reporting an exit (so we'd hang if we waited for it explicitly in
92 that case). The exec event is instead reported to the TGID pid.
94 The solution is to always use -1 and WNOHANG, together with
97 First, we use non-blocking waitpid to check for events. If nothing is
98 found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives,
99 it means something happened to a child process. As soon as we know
100 there's an event, we get back to calling nonblocking waitpid.
102 Note that SIGCHLD should be blocked between waitpid and sigsuspend
103 calls, so that we don't miss a signal. If SIGCHLD arrives in between,
104 when it's blocked, the signal becomes pending and sigsuspend
105 immediately notices it and returns.
107 Waiting for events in async mode (TARGET_WNOHANG)
108 =================================================
110 In async mode, GDB should always be ready to handle both user input
111 and target events, so neither blocking waitpid nor sigsuspend are
112 viable options. Instead, we should asynchronously notify the GDB main
113 event loop whenever there's an unprocessed event from the target. We
114 detect asynchronous target events by handling SIGCHLD signals. To
115 notify the event loop about target events, the self-pipe trick is used
116 --- a pipe is registered as waitable event source in the event loop,
117 the event loop select/poll's on the read end of this pipe (as well on
118 other event sources, e.g., stdin), and the SIGCHLD handler writes a
119 byte to this pipe. This is more portable than relying on
120 pselect/ppoll, since on kernels that lack those syscalls, libc
121 emulates them with select/poll+sigprocmask, and that is racy
122 (a.k.a. plain broken).
124 Obviously, if we fail to notify the event loop if there's a target
125 event, it's bad. OTOH, if we notify the event loop when there's no
126 event from the target, linux_nat_wait will detect that there's no real
127 event to report, and return event of type TARGET_WAITKIND_IGNORE.
128 This is mostly harmless, but it will waste time and is better avoided.
130 The main design point is that every time GDB is outside linux-nat.c,
131 we have a SIGCHLD handler installed that is called when something
132 happens to the target and notifies the GDB event loop. Whenever GDB
133 core decides to handle the event, and calls into linux-nat.c, we
134 process things as in sync mode, except that the we never block in
137 While processing an event, we may end up momentarily blocked in
138 waitpid calls. Those waitpid calls, while blocking, are guarantied to
139 return quickly. E.g., in all-stop mode, before reporting to the core
140 that an LWP hit a breakpoint, all LWPs are stopped by sending them
141 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
142 Note that this is different from blocking indefinitely waiting for the
143 next event --- here, we're already handling an event.
148 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
149 signal is not entirely significant; we just need for a signal to be delivered,
150 so that we can intercept it. SIGSTOP's advantage is that it can not be
151 blocked. A disadvantage is that it is not a real-time signal, so it can only
152 be queued once; we do not keep track of other sources of SIGSTOP.
154 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
155 use them, because they have special behavior when the signal is generated -
156 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
157 kills the entire thread group.
159 A delivered SIGSTOP would stop the entire thread group, not just the thread we
160 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
161 cancel it (by PTRACE_CONT without passing SIGSTOP).
163 We could use a real-time signal instead. This would solve those problems; we
164 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
165 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
166 generates it, and there are races with trying to find a signal that is not
172 The case of a thread group (process) with 3 or more threads, and a
173 thread other than the leader execs is worth detailing:
175 On an exec, the Linux kernel destroys all threads except the execing
176 one in the thread group, and resets the execing thread's tid to the
177 tgid. No exit notification is sent for the execing thread -- from the
178 ptracer's perspective, it appears as though the execing thread just
179 vanishes. Until we reap all other threads except the leader and the
180 execing thread, the leader will be zombie, and the execing thread will
181 be in `D (disc sleep)' state. As soon as all other threads are
182 reaped, the execing thread changes its tid to the tgid, and the
183 previous (zombie) leader vanishes, giving place to the "new"
187 #define O_LARGEFILE 0
190 struct linux_nat_target
*linux_target
;
192 /* Does the current host support PTRACE_GETREGSET? */
193 enum tribool have_ptrace_getregset
= TRIBOOL_UNKNOWN
;
195 static unsigned int debug_linux_nat
;
197 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
198 struct cmd_list_element
*c
, const char *value
)
200 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
204 struct simple_pid_list
208 struct simple_pid_list
*next
;
210 struct simple_pid_list
*stopped_pids
;
212 /* Whether target_thread_events is in effect. */
213 static int report_thread_events
;
215 /* Async mode support. */
217 /* The read/write ends of the pipe registered as waitable file in the
219 static int linux_nat_event_pipe
[2] = { -1, -1 };
221 /* True if we're currently in async mode. */
222 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
224 /* Flush the event pipe. */
227 async_file_flush (void)
234 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
236 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
239 /* Put something (anything, doesn't matter what, or how much) in event
240 pipe, so that the select/poll in the event-loop realizes we have
241 something to process. */
244 async_file_mark (void)
248 /* It doesn't really matter what the pipe contains, as long we end
249 up with something in it. Might as well flush the previous
255 ret
= write (linux_nat_event_pipe
[1], "+", 1);
257 while (ret
== -1 && errno
== EINTR
);
259 /* Ignore EAGAIN. If the pipe is full, the event loop will already
260 be awakened anyway. */
263 static int kill_lwp (int lwpid
, int signo
);
265 static int stop_callback (struct lwp_info
*lp
, void *data
);
266 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
);
268 static void block_child_signals (sigset_t
*prev_mask
);
269 static void restore_child_signals_mask (sigset_t
*prev_mask
);
272 static struct lwp_info
*add_lwp (ptid_t ptid
);
273 static void purge_lwp_list (int pid
);
274 static void delete_lwp (ptid_t ptid
);
275 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
277 static int lwp_status_pending_p (struct lwp_info
*lp
);
279 static void save_stop_reason (struct lwp_info
*lp
);
284 /* See nat/linux-nat.h. */
287 ptid_of_lwp (struct lwp_info
*lwp
)
292 /* See nat/linux-nat.h. */
295 lwp_set_arch_private_info (struct lwp_info
*lwp
,
296 struct arch_lwp_info
*info
)
298 lwp
->arch_private
= info
;
301 /* See nat/linux-nat.h. */
303 struct arch_lwp_info
*
304 lwp_arch_private_info (struct lwp_info
*lwp
)
306 return lwp
->arch_private
;
309 /* See nat/linux-nat.h. */
312 lwp_is_stopped (struct lwp_info
*lwp
)
317 /* See nat/linux-nat.h. */
319 enum target_stop_reason
320 lwp_stop_reason (struct lwp_info
*lwp
)
322 return lwp
->stop_reason
;
325 /* See nat/linux-nat.h. */
328 lwp_is_stepping (struct lwp_info
*lwp
)
334 /* Trivial list manipulation functions to keep track of a list of
335 new stopped processes. */
337 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
339 struct simple_pid_list
*new_pid
= XNEW (struct simple_pid_list
);
342 new_pid
->status
= status
;
343 new_pid
->next
= *listp
;
348 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
350 struct simple_pid_list
**p
;
352 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
353 if ((*p
)->pid
== pid
)
355 struct simple_pid_list
*next
= (*p
)->next
;
357 *statusp
= (*p
)->status
;
365 /* Return the ptrace options that we want to try to enable. */
368 linux_nat_ptrace_options (int attached
)
373 options
|= PTRACE_O_EXITKILL
;
375 options
|= (PTRACE_O_TRACESYSGOOD
376 | PTRACE_O_TRACEVFORKDONE
377 | PTRACE_O_TRACEVFORK
379 | PTRACE_O_TRACEEXEC
);
384 /* Initialize ptrace and procfs warnings and check for supported
385 ptrace features given PID.
387 ATTACHED should be nonzero iff we attached to the inferior. */
390 linux_init_ptrace_procfs (pid_t pid
, int attached
)
392 int options
= linux_nat_ptrace_options (attached
);
394 linux_enable_event_reporting (pid
, options
);
395 linux_ptrace_init_warnings ();
396 linux_proc_init_warnings ();
399 linux_nat_target::~linux_nat_target ()
403 linux_nat_target::post_attach (int pid
)
405 linux_init_ptrace_procfs (pid
, 1);
409 linux_nat_target::post_startup_inferior (ptid_t ptid
)
411 linux_init_ptrace_procfs (ptid
.pid (), 0);
414 /* Return the number of known LWPs in the tgid given by PID. */
422 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
423 if (lp
->ptid
.pid () == pid
)
429 /* Deleter for lwp_info unique_ptr specialisation. */
433 void operator() (struct lwp_info
*lwp
) const
435 delete_lwp (lwp
->ptid
);
439 /* A unique_ptr specialisation for lwp_info. */
441 typedef std::unique_ptr
<struct lwp_info
, lwp_deleter
> lwp_info_up
;
443 /* Target hook for follow_fork. On entry inferior_ptid must be the
444 ptid of the followed inferior. At return, inferior_ptid will be
448 linux_nat_target::follow_fork (int follow_child
, int detach_fork
)
452 struct lwp_info
*child_lp
= NULL
;
454 ptid_t parent_ptid
, child_ptid
;
455 int parent_pid
, child_pid
;
457 has_vforked
= (inferior_thread ()->pending_follow
.kind
458 == TARGET_WAITKIND_VFORKED
);
459 parent_ptid
= inferior_ptid
;
460 child_ptid
= inferior_thread ()->pending_follow
.value
.related_pid
;
461 parent_pid
= parent_ptid
.lwp ();
462 child_pid
= child_ptid
.lwp ();
464 /* We're already attached to the parent, by default. */
465 child_lp
= add_lwp (child_ptid
);
466 child_lp
->stopped
= 1;
467 child_lp
->last_resume_kind
= resume_stop
;
469 /* Detach new forked process? */
472 int child_stop_signal
= 0;
473 bool detach_child
= true;
475 /* Move CHILD_LP into a unique_ptr and clear the source pointer
476 to prevent us doing anything stupid with it. */
477 lwp_info_up
child_lp_ptr (child_lp
);
480 linux_target
->low_prepare_to_resume (child_lp_ptr
.get ());
482 /* When debugging an inferior in an architecture that supports
483 hardware single stepping on a kernel without commit
484 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
485 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
486 set if the parent process had them set.
487 To work around this, single step the child process
488 once before detaching to clear the flags. */
490 /* Note that we consult the parent's architecture instead of
491 the child's because there's no inferior for the child at
493 if (!gdbarch_software_single_step_p (target_thread_architecture
498 linux_disable_event_reporting (child_pid
);
499 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
500 perror_with_name (_("Couldn't do single step"));
501 if (my_waitpid (child_pid
, &status
, 0) < 0)
502 perror_with_name (_("Couldn't wait vfork process"));
505 detach_child
= WIFSTOPPED (status
);
506 child_stop_signal
= WSTOPSIG (status
);
512 int signo
= child_stop_signal
;
515 && !signal_pass_state (gdb_signal_from_host (signo
)))
517 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
522 scoped_restore save_inferior_ptid
523 = make_scoped_restore (&inferior_ptid
);
524 inferior_ptid
= child_ptid
;
526 /* Let the thread_db layer learn about this new process. */
527 check_for_thread_db ();
532 struct lwp_info
*parent_lp
;
534 parent_lp
= find_lwp_pid (parent_ptid
);
535 gdb_assert (linux_supports_tracefork () >= 0);
537 if (linux_supports_tracevforkdone ())
540 fprintf_unfiltered (gdb_stdlog
,
541 "LCFF: waiting for VFORK_DONE on %d\n",
543 parent_lp
->stopped
= 1;
545 /* We'll handle the VFORK_DONE event like any other
546 event, in target_wait. */
550 /* We can't insert breakpoints until the child has
551 finished with the shared memory region. We need to
552 wait until that happens. Ideal would be to just
554 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
555 - waitpid (parent_pid, &status, __WALL);
556 However, most architectures can't handle a syscall
557 being traced on the way out if it wasn't traced on
560 We might also think to loop, continuing the child
561 until it exits or gets a SIGTRAP. One problem is
562 that the child might call ptrace with PTRACE_TRACEME.
564 There's no simple and reliable way to figure out when
565 the vforked child will be done with its copy of the
566 shared memory. We could step it out of the syscall,
567 two instructions, let it go, and then single-step the
568 parent once. When we have hardware single-step, this
569 would work; with software single-step it could still
570 be made to work but we'd have to be able to insert
571 single-step breakpoints in the child, and we'd have
572 to insert -just- the single-step breakpoint in the
573 parent. Very awkward.
575 In the end, the best we can do is to make sure it
576 runs for a little while. Hopefully it will be out of
577 range of any breakpoints we reinsert. Usually this
578 is only the single-step breakpoint at vfork's return
582 fprintf_unfiltered (gdb_stdlog
,
583 "LCFF: no VFORK_DONE "
584 "support, sleeping a bit\n");
588 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
589 and leave it pending. The next linux_nat_resume call
590 will notice a pending event, and bypasses actually
591 resuming the inferior. */
592 parent_lp
->status
= 0;
593 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
594 parent_lp
->stopped
= 1;
596 /* If we're in async mode, need to tell the event loop
597 there's something here to process. */
598 if (target_is_async_p ())
605 struct lwp_info
*child_lp
;
607 child_lp
= add_lwp (inferior_ptid
);
608 child_lp
->stopped
= 1;
609 child_lp
->last_resume_kind
= resume_stop
;
611 /* Let the thread_db layer learn about this new process. */
612 check_for_thread_db ();
620 linux_nat_target::insert_fork_catchpoint (int pid
)
622 return !linux_supports_tracefork ();
626 linux_nat_target::remove_fork_catchpoint (int pid
)
632 linux_nat_target::insert_vfork_catchpoint (int pid
)
634 return !linux_supports_tracefork ();
638 linux_nat_target::remove_vfork_catchpoint (int pid
)
644 linux_nat_target::insert_exec_catchpoint (int pid
)
646 return !linux_supports_tracefork ();
650 linux_nat_target::remove_exec_catchpoint (int pid
)
656 linux_nat_target::set_syscall_catchpoint (int pid
, bool needed
, int any_count
,
657 gdb::array_view
<const int> syscall_counts
)
659 if (!linux_supports_tracesysgood ())
662 /* On GNU/Linux, we ignore the arguments. It means that we only
663 enable the syscall catchpoints, but do not disable them.
665 Also, we do not use the `syscall_counts' information because we do not
666 filter system calls here. We let GDB do the logic for us. */
670 /* List of known LWPs, keyed by LWP PID. This speeds up the common
671 case of mapping a PID returned from the kernel to our corresponding
672 lwp_info data structure. */
673 static htab_t lwp_lwpid_htab
;
675 /* Calculate a hash from a lwp_info's LWP PID. */
678 lwp_info_hash (const void *ap
)
680 const struct lwp_info
*lp
= (struct lwp_info
*) ap
;
681 pid_t pid
= lp
->ptid
.lwp ();
683 return iterative_hash_object (pid
, 0);
686 /* Equality function for the lwp_info hash table. Compares the LWP's
690 lwp_lwpid_htab_eq (const void *a
, const void *b
)
692 const struct lwp_info
*entry
= (const struct lwp_info
*) a
;
693 const struct lwp_info
*element
= (const struct lwp_info
*) b
;
695 return entry
->ptid
.lwp () == element
->ptid
.lwp ();
698 /* Create the lwp_lwpid_htab hash table. */
701 lwp_lwpid_htab_create (void)
703 lwp_lwpid_htab
= htab_create (100, lwp_info_hash
, lwp_lwpid_htab_eq
, NULL
);
706 /* Add LP to the hash table. */
709 lwp_lwpid_htab_add_lwp (struct lwp_info
*lp
)
713 slot
= htab_find_slot (lwp_lwpid_htab
, lp
, INSERT
);
714 gdb_assert (slot
!= NULL
&& *slot
== NULL
);
718 /* Head of doubly-linked list of known LWPs. Sorted by reverse
719 creation order. This order is assumed in some cases. E.g.,
720 reaping status after killing alls lwps of a process: the leader LWP
721 must be reaped last. */
722 struct lwp_info
*lwp_list
;
724 /* Add LP to sorted-by-reverse-creation-order doubly-linked list. */
727 lwp_list_add (struct lwp_info
*lp
)
730 if (lwp_list
!= NULL
)
735 /* Remove LP from sorted-by-reverse-creation-order doubly-linked
739 lwp_list_remove (struct lwp_info
*lp
)
741 /* Remove from sorted-by-creation-order list. */
742 if (lp
->next
!= NULL
)
743 lp
->next
->prev
= lp
->prev
;
744 if (lp
->prev
!= NULL
)
745 lp
->prev
->next
= lp
->next
;
752 /* Original signal mask. */
753 static sigset_t normal_mask
;
755 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
756 _initialize_linux_nat. */
757 static sigset_t suspend_mask
;
759 /* Signals to block to make that sigsuspend work. */
760 static sigset_t blocked_mask
;
762 /* SIGCHLD action. */
763 struct sigaction sigchld_action
;
765 /* Block child signals (SIGCHLD and linux threads signals), and store
766 the previous mask in PREV_MASK. */
769 block_child_signals (sigset_t
*prev_mask
)
771 /* Make sure SIGCHLD is blocked. */
772 if (!sigismember (&blocked_mask
, SIGCHLD
))
773 sigaddset (&blocked_mask
, SIGCHLD
);
775 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
778 /* Restore child signals mask, previously returned by
779 block_child_signals. */
782 restore_child_signals_mask (sigset_t
*prev_mask
)
784 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
787 /* Mask of signals to pass directly to the inferior. */
788 static sigset_t pass_mask
;
790 /* Update signals to pass to the inferior. */
792 linux_nat_target::pass_signals (int numsigs
, const unsigned char *pass_signals
)
796 sigemptyset (&pass_mask
);
798 for (signo
= 1; signo
< NSIG
; signo
++)
800 int target_signo
= gdb_signal_from_host (signo
);
801 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
802 sigaddset (&pass_mask
, signo
);
808 /* Prototypes for local functions. */
809 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
810 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
);
811 static int check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
);
815 /* Destroy and free LP. */
818 lwp_free (struct lwp_info
*lp
)
820 /* Let the arch specific bits release arch_lwp_info. */
821 linux_target
->low_delete_thread (lp
->arch_private
);
826 /* Traversal function for purge_lwp_list. */
829 lwp_lwpid_htab_remove_pid (void **slot
, void *info
)
831 struct lwp_info
*lp
= (struct lwp_info
*) *slot
;
832 int pid
= *(int *) info
;
834 if (lp
->ptid
.pid () == pid
)
836 htab_clear_slot (lwp_lwpid_htab
, slot
);
837 lwp_list_remove (lp
);
844 /* Remove all LWPs belong to PID from the lwp list. */
847 purge_lwp_list (int pid
)
849 htab_traverse_noresize (lwp_lwpid_htab
, lwp_lwpid_htab_remove_pid
, &pid
);
852 /* Add the LWP specified by PTID to the list. PTID is the first LWP
853 in the process. Return a pointer to the structure describing the
856 This differs from add_lwp in that we don't let the arch specific
857 bits know about this new thread. Current clients of this callback
858 take the opportunity to install watchpoints in the new thread, and
859 we shouldn't do that for the first thread. If we're spawning a
860 child ("run"), the thread executes the shell wrapper first, and we
861 shouldn't touch it until it execs the program we want to debug.
862 For "attach", it'd be okay to call the callback, but it's not
863 necessary, because watchpoints can't yet have been inserted into
866 static struct lwp_info
*
867 add_initial_lwp (ptid_t ptid
)
871 gdb_assert (ptid
.lwp_p ());
873 lp
= XNEW (struct lwp_info
);
875 memset (lp
, 0, sizeof (struct lwp_info
));
877 lp
->last_resume_kind
= resume_continue
;
878 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
883 /* Add to sorted-by-reverse-creation-order list. */
886 /* Add to keyed-by-pid htab. */
887 lwp_lwpid_htab_add_lwp (lp
);
892 /* Add the LWP specified by PID to the list. Return a pointer to the
893 structure describing the new LWP. The LWP should already be
896 static struct lwp_info
*
897 add_lwp (ptid_t ptid
)
901 lp
= add_initial_lwp (ptid
);
903 /* Let the arch specific bits know about this new thread. Current
904 clients of this callback take the opportunity to install
905 watchpoints in the new thread. We don't do this for the first
906 thread though. See add_initial_lwp. */
907 linux_target
->low_new_thread (lp
);
912 /* Remove the LWP specified by PID from the list. */
915 delete_lwp (ptid_t ptid
)
919 struct lwp_info dummy
;
922 slot
= htab_find_slot (lwp_lwpid_htab
, &dummy
, NO_INSERT
);
926 lp
= *(struct lwp_info
**) slot
;
927 gdb_assert (lp
!= NULL
);
929 htab_clear_slot (lwp_lwpid_htab
, slot
);
931 /* Remove from sorted-by-creation-order list. */
932 lwp_list_remove (lp
);
938 /* Return a pointer to the structure describing the LWP corresponding
939 to PID. If no corresponding LWP could be found, return NULL. */
941 static struct lwp_info
*
942 find_lwp_pid (ptid_t ptid
)
946 struct lwp_info dummy
;
953 dummy
.ptid
= ptid_t (0, lwp
, 0);
954 lp
= (struct lwp_info
*) htab_find (lwp_lwpid_htab
, &dummy
);
958 /* See nat/linux-nat.h. */
961 iterate_over_lwps (ptid_t filter
,
962 iterate_over_lwps_ftype callback
,
965 struct lwp_info
*lp
, *lpnext
;
967 for (lp
= lwp_list
; lp
; lp
= lpnext
)
971 if (lp
->ptid
.matches (filter
))
973 if ((*callback
) (lp
, data
) != 0)
981 /* Update our internal state when changing from one checkpoint to
982 another indicated by NEW_PTID. We can only switch single-threaded
983 applications, so we only create one new LWP, and the previous list
987 linux_nat_switch_fork (ptid_t new_ptid
)
991 purge_lwp_list (inferior_ptid
.pid ());
993 lp
= add_lwp (new_ptid
);
996 /* This changes the thread's ptid while preserving the gdb thread
997 num. Also changes the inferior pid, while preserving the
999 thread_change_ptid (inferior_ptid
, new_ptid
);
1001 /* We've just told GDB core that the thread changed target id, but,
1002 in fact, it really is a different thread, with different register
1004 registers_changed ();
1007 /* Handle the exit of a single thread LP. */
1010 exit_lwp (struct lwp_info
*lp
)
1012 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1016 if (print_thread_events
)
1017 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
1022 delete_lwp (lp
->ptid
);
1025 /* Wait for the LWP specified by LP, which we have just attached to.
1026 Returns a wait status for that LWP, to cache. */
1029 linux_nat_post_attach_wait (ptid_t ptid
, int *signalled
)
1031 pid_t new_pid
, pid
= ptid
.lwp ();
1034 if (linux_proc_pid_is_stopped (pid
))
1036 if (debug_linux_nat
)
1037 fprintf_unfiltered (gdb_stdlog
,
1038 "LNPAW: Attaching to a stopped process\n");
1040 /* The process is definitely stopped. It is in a job control
1041 stop, unless the kernel predates the TASK_STOPPED /
1042 TASK_TRACED distinction, in which case it might be in a
1043 ptrace stop. Make sure it is in a ptrace stop; from there we
1044 can kill it, signal it, et cetera.
1046 First make sure there is a pending SIGSTOP. Since we are
1047 already attached, the process can not transition from stopped
1048 to running without a PTRACE_CONT; so we know this signal will
1049 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1050 probably already in the queue (unless this kernel is old
1051 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1052 is not an RT signal, it can only be queued once. */
1053 kill_lwp (pid
, SIGSTOP
);
1055 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1056 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1057 ptrace (PTRACE_CONT
, pid
, 0, 0);
1060 /* Make sure the initial process is stopped. The user-level threads
1061 layer might want to poke around in the inferior, and that won't
1062 work if things haven't stabilized yet. */
1063 new_pid
= my_waitpid (pid
, &status
, __WALL
);
1064 gdb_assert (pid
== new_pid
);
1066 if (!WIFSTOPPED (status
))
1068 /* The pid we tried to attach has apparently just exited. */
1069 if (debug_linux_nat
)
1070 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1071 pid
, status_to_str (status
));
1075 if (WSTOPSIG (status
) != SIGSTOP
)
1078 if (debug_linux_nat
)
1079 fprintf_unfiltered (gdb_stdlog
,
1080 "LNPAW: Received %s after attaching\n",
1081 status_to_str (status
));
1088 linux_nat_target::create_inferior (const char *exec_file
,
1089 const std::string
&allargs
,
1090 char **env
, int from_tty
)
1092 maybe_disable_address_space_randomization restore_personality
1093 (disable_randomization
);
1095 /* The fork_child mechanism is synchronous and calls target_wait, so
1096 we have to mask the async mode. */
1098 /* Make sure we report all signals during startup. */
1099 pass_signals (0, NULL
);
1101 inf_ptrace_target::create_inferior (exec_file
, allargs
, env
, from_tty
);
1104 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1105 already attached. Returns true if a new LWP is found, false
1109 attach_proc_task_lwp_callback (ptid_t ptid
)
1111 struct lwp_info
*lp
;
1113 /* Ignore LWPs we're already attached to. */
1114 lp
= find_lwp_pid (ptid
);
1117 int lwpid
= ptid
.lwp ();
1119 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1123 /* Be quiet if we simply raced with the thread exiting.
1124 EPERM is returned if the thread's task still exists, and
1125 is marked as exited or zombie, as well as other
1126 conditions, so in that case, confirm the status in
1127 /proc/PID/status. */
1129 || (err
== EPERM
&& linux_proc_pid_is_gone (lwpid
)))
1131 if (debug_linux_nat
)
1133 fprintf_unfiltered (gdb_stdlog
,
1134 "Cannot attach to lwp %d: "
1135 "thread is gone (%d: %s)\n",
1136 lwpid
, err
, safe_strerror (err
));
1142 = linux_ptrace_attach_fail_reason_string (ptid
, err
);
1144 warning (_("Cannot attach to lwp %d: %s"),
1145 lwpid
, reason
.c_str ());
1150 if (debug_linux_nat
)
1151 fprintf_unfiltered (gdb_stdlog
,
1152 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1153 target_pid_to_str (ptid
));
1155 lp
= add_lwp (ptid
);
1157 /* The next time we wait for this LWP we'll see a SIGSTOP as
1158 PTRACE_ATTACH brings it to a halt. */
1161 /* We need to wait for a stop before being able to make the
1162 next ptrace call on this LWP. */
1163 lp
->must_set_ptrace_flags
= 1;
1165 /* So that wait collects the SIGSTOP. */
1168 /* Also add the LWP to gdb's thread list, in case a
1169 matching libthread_db is not found (or the process uses
1171 add_thread (lp
->ptid
);
1172 set_running (lp
->ptid
, 1);
1173 set_executing (lp
->ptid
, 1);
1182 linux_nat_target::attach (const char *args
, int from_tty
)
1184 struct lwp_info
*lp
;
1188 /* Make sure we report all signals during attach. */
1189 pass_signals (0, NULL
);
1193 inf_ptrace_target::attach (args
, from_tty
);
1195 CATCH (ex
, RETURN_MASK_ERROR
)
1197 pid_t pid
= parse_pid_to_attach (args
);
1198 std::string reason
= linux_ptrace_attach_fail_reason (pid
);
1200 if (!reason
.empty ())
1201 throw_error (ex
.error
, "warning: %s\n%s", reason
.c_str (), ex
.message
);
1203 throw_error (ex
.error
, "%s", ex
.message
);
1207 /* The ptrace base target adds the main thread with (pid,0,0)
1208 format. Decorate it with lwp info. */
1209 ptid
= ptid_t (inferior_ptid
.pid (),
1210 inferior_ptid
.pid (),
1212 thread_change_ptid (inferior_ptid
, ptid
);
1214 /* Add the initial process as the first LWP to the list. */
1215 lp
= add_initial_lwp (ptid
);
1217 status
= linux_nat_post_attach_wait (lp
->ptid
, &lp
->signalled
);
1218 if (!WIFSTOPPED (status
))
1220 if (WIFEXITED (status
))
1222 int exit_code
= WEXITSTATUS (status
);
1224 target_terminal::ours ();
1225 target_mourn_inferior (inferior_ptid
);
1227 error (_("Unable to attach: program exited normally."));
1229 error (_("Unable to attach: program exited with code %d."),
1232 else if (WIFSIGNALED (status
))
1234 enum gdb_signal signo
;
1236 target_terminal::ours ();
1237 target_mourn_inferior (inferior_ptid
);
1239 signo
= gdb_signal_from_host (WTERMSIG (status
));
1240 error (_("Unable to attach: program terminated with signal "
1242 gdb_signal_to_name (signo
),
1243 gdb_signal_to_string (signo
));
1246 internal_error (__FILE__
, __LINE__
,
1247 _("unexpected status %d for PID %ld"),
1248 status
, (long) ptid
.lwp ());
1253 /* Save the wait status to report later. */
1255 if (debug_linux_nat
)
1256 fprintf_unfiltered (gdb_stdlog
,
1257 "LNA: waitpid %ld, saving status %s\n",
1258 (long) lp
->ptid
.pid (), status_to_str (status
));
1260 lp
->status
= status
;
1262 /* We must attach to every LWP. If /proc is mounted, use that to
1263 find them now. The inferior may be using raw clone instead of
1264 using pthreads. But even if it is using pthreads, thread_db
1265 walks structures in the inferior's address space to find the list
1266 of threads/LWPs, and those structures may well be corrupted.
1267 Note that once thread_db is loaded, we'll still use it to list
1268 threads and associate pthread info with each LWP. */
1269 linux_proc_attach_tgid_threads (lp
->ptid
.pid (),
1270 attach_proc_task_lwp_callback
);
1272 if (target_can_async_p ())
1276 /* Get pending signal of THREAD as a host signal number, for detaching
1277 purposes. This is the signal the thread last stopped for, which we
1278 need to deliver to the thread when detaching, otherwise, it'd be
1282 get_detach_signal (struct lwp_info
*lp
)
1284 enum gdb_signal signo
= GDB_SIGNAL_0
;
1286 /* If we paused threads momentarily, we may have stored pending
1287 events in lp->status or lp->waitstatus (see stop_wait_callback),
1288 and GDB core hasn't seen any signal for those threads.
1289 Otherwise, the last signal reported to the core is found in the
1290 thread object's stop_signal.
1292 There's a corner case that isn't handled here at present. Only
1293 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1294 stop_signal make sense as a real signal to pass to the inferior.
1295 Some catchpoint related events, like
1296 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1297 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1298 those traps are debug API (ptrace in our case) related and
1299 induced; the inferior wouldn't see them if it wasn't being
1300 traced. Hence, we should never pass them to the inferior, even
1301 when set to pass state. Since this corner case isn't handled by
1302 infrun.c when proceeding with a signal, for consistency, neither
1303 do we handle it here (or elsewhere in the file we check for
1304 signal pass state). Normally SIGTRAP isn't set to pass state, so
1305 this is really a corner case. */
1307 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1308 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1309 else if (lp
->status
)
1310 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1313 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1315 if (target_is_non_stop_p () && !tp
->executing
)
1317 if (tp
->suspend
.waitstatus_pending_p
)
1318 signo
= tp
->suspend
.waitstatus
.value
.sig
;
1320 signo
= tp
->suspend
.stop_signal
;
1322 else if (!target_is_non_stop_p ())
1324 struct target_waitstatus last
;
1327 get_last_target_status (&last_ptid
, &last
);
1329 if (lp
->ptid
.lwp () == last_ptid
.lwp ())
1330 signo
= tp
->suspend
.stop_signal
;
1334 if (signo
== GDB_SIGNAL_0
)
1336 if (debug_linux_nat
)
1337 fprintf_unfiltered (gdb_stdlog
,
1338 "GPT: lwp %s has no pending signal\n",
1339 target_pid_to_str (lp
->ptid
));
1341 else if (!signal_pass_state (signo
))
1343 if (debug_linux_nat
)
1344 fprintf_unfiltered (gdb_stdlog
,
1345 "GPT: lwp %s had signal %s, "
1346 "but it is in no pass state\n",
1347 target_pid_to_str (lp
->ptid
),
1348 gdb_signal_to_string (signo
));
1352 if (debug_linux_nat
)
1353 fprintf_unfiltered (gdb_stdlog
,
1354 "GPT: lwp %s has pending signal %s\n",
1355 target_pid_to_str (lp
->ptid
),
1356 gdb_signal_to_string (signo
));
1358 return gdb_signal_to_host (signo
);
1364 /* Detach from LP. If SIGNO_P is non-NULL, then it points to the
1365 signal number that should be passed to the LWP when detaching.
1366 Otherwise pass any pending signal the LWP may have, if any. */
1369 detach_one_lwp (struct lwp_info
*lp
, int *signo_p
)
1371 int lwpid
= lp
->ptid
.lwp ();
1374 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1376 if (debug_linux_nat
&& lp
->status
)
1377 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1378 strsignal (WSTOPSIG (lp
->status
)),
1379 target_pid_to_str (lp
->ptid
));
1381 /* If there is a pending SIGSTOP, get rid of it. */
1384 if (debug_linux_nat
)
1385 fprintf_unfiltered (gdb_stdlog
,
1386 "DC: Sending SIGCONT to %s\n",
1387 target_pid_to_str (lp
->ptid
));
1389 kill_lwp (lwpid
, SIGCONT
);
1393 if (signo_p
== NULL
)
1395 /* Pass on any pending signal for this LWP. */
1396 signo
= get_detach_signal (lp
);
1401 /* Preparing to resume may try to write registers, and fail if the
1402 lwp is zombie. If that happens, ignore the error. We'll handle
1403 it below, when detach fails with ESRCH. */
1406 linux_target
->low_prepare_to_resume (lp
);
1408 CATCH (ex
, RETURN_MASK_ERROR
)
1410 if (!check_ptrace_stopped_lwp_gone (lp
))
1411 throw_exception (ex
);
1415 if (ptrace (PTRACE_DETACH
, lwpid
, 0, signo
) < 0)
1417 int save_errno
= errno
;
1419 /* We know the thread exists, so ESRCH must mean the lwp is
1420 zombie. This can happen if one of the already-detached
1421 threads exits the whole thread group. In that case we're
1422 still attached, and must reap the lwp. */
1423 if (save_errno
== ESRCH
)
1427 ret
= my_waitpid (lwpid
, &status
, __WALL
);
1430 warning (_("Couldn't reap LWP %d while detaching: %s"),
1431 lwpid
, strerror (errno
));
1433 else if (!WIFEXITED (status
) && !WIFSIGNALED (status
))
1435 warning (_("Reaping LWP %d while detaching "
1436 "returned unexpected status 0x%x"),
1442 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1443 safe_strerror (save_errno
));
1446 else if (debug_linux_nat
)
1448 fprintf_unfiltered (gdb_stdlog
,
1449 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1450 target_pid_to_str (lp
->ptid
),
1454 delete_lwp (lp
->ptid
);
1458 detach_callback (struct lwp_info
*lp
, void *data
)
1460 /* We don't actually detach from the thread group leader just yet.
1461 If the thread group exits, we must reap the zombie clone lwps
1462 before we're able to reap the leader. */
1463 if (lp
->ptid
.lwp () != lp
->ptid
.pid ())
1464 detach_one_lwp (lp
, NULL
);
1469 linux_nat_target::detach (inferior
*inf
, int from_tty
)
1471 struct lwp_info
*main_lwp
;
1474 /* Don't unregister from the event loop, as there may be other
1475 inferiors running. */
1477 /* Stop all threads before detaching. ptrace requires that the
1478 thread is stopped to sucessfully detach. */
1479 iterate_over_lwps (ptid_t (pid
), stop_callback
, NULL
);
1480 /* ... and wait until all of them have reported back that
1481 they're no longer running. */
1482 iterate_over_lwps (ptid_t (pid
), stop_wait_callback
, NULL
);
1484 iterate_over_lwps (ptid_t (pid
), detach_callback
, NULL
);
1486 /* Only the initial process should be left right now. */
1487 gdb_assert (num_lwps (pid
) == 1);
1489 main_lwp
= find_lwp_pid (ptid_t (pid
));
1491 if (forks_exist_p ())
1493 /* Multi-fork case. The current inferior_ptid is being detached
1494 from, but there are other viable forks to debug. Detach from
1495 the current fork, and context-switch to the first
1497 linux_fork_detach (from_tty
);
1501 target_announce_detach (from_tty
);
1503 /* Pass on any pending signal for the last LWP. */
1504 int signo
= get_detach_signal (main_lwp
);
1506 detach_one_lwp (main_lwp
, &signo
);
1508 detach_success (inf
);
1512 /* Resume execution of the inferior process. If STEP is nonzero,
1513 single-step it. If SIGNAL is nonzero, give it that signal. */
1516 linux_resume_one_lwp_throw (struct lwp_info
*lp
, int step
,
1517 enum gdb_signal signo
)
1521 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1522 We only presently need that if the LWP is stepped though (to
1523 handle the case of stepping a breakpoint instruction). */
1526 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
1528 lp
->stop_pc
= regcache_read_pc (regcache
);
1533 linux_target
->low_prepare_to_resume (lp
);
1534 linux_target
->low_resume (lp
->ptid
, step
, signo
);
1536 /* Successfully resumed. Clear state that no longer makes sense,
1537 and mark the LWP as running. Must not do this before resuming
1538 otherwise if that fails other code will be confused. E.g., we'd
1539 later try to stop the LWP and hang forever waiting for a stop
1540 status. Note that we must not throw after this is cleared,
1541 otherwise handle_zombie_lwp_error would get confused. */
1544 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1545 registers_changed_ptid (lp
->ptid
);
1548 /* Called when we try to resume a stopped LWP and that errors out. If
1549 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1550 or about to become), discard the error, clear any pending status
1551 the LWP may have, and return true (we'll collect the exit status
1552 soon enough). Otherwise, return false. */
1555 check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
)
1557 /* If we get an error after resuming the LWP successfully, we'd
1558 confuse !T state for the LWP being gone. */
1559 gdb_assert (lp
->stopped
);
1561 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1562 because even if ptrace failed with ESRCH, the tracee may be "not
1563 yet fully dead", but already refusing ptrace requests. In that
1564 case the tracee has 'R (Running)' state for a little bit
1565 (observed in Linux 3.18). See also the note on ESRCH in the
1566 ptrace(2) man page. Instead, check whether the LWP has any state
1567 other than ptrace-stopped. */
1569 /* Don't assume anything if /proc/PID/status can't be read. */
1570 if (linux_proc_pid_is_trace_stopped_nowarn (lp
->ptid
.lwp ()) == 0)
1572 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1574 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
1580 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1581 disappears while we try to resume it. */
1584 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1588 linux_resume_one_lwp_throw (lp
, step
, signo
);
1590 CATCH (ex
, RETURN_MASK_ERROR
)
1592 if (!check_ptrace_stopped_lwp_gone (lp
))
1593 throw_exception (ex
);
1601 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1605 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
1607 if (inf
->vfork_child
!= NULL
)
1609 if (debug_linux_nat
)
1610 fprintf_unfiltered (gdb_stdlog
,
1611 "RC: Not resuming %s (vfork parent)\n",
1612 target_pid_to_str (lp
->ptid
));
1614 else if (!lwp_status_pending_p (lp
))
1616 if (debug_linux_nat
)
1617 fprintf_unfiltered (gdb_stdlog
,
1618 "RC: Resuming sibling %s, %s, %s\n",
1619 target_pid_to_str (lp
->ptid
),
1620 (signo
!= GDB_SIGNAL_0
1621 ? strsignal (gdb_signal_to_host (signo
))
1623 step
? "step" : "resume");
1625 linux_resume_one_lwp (lp
, step
, signo
);
1629 if (debug_linux_nat
)
1630 fprintf_unfiltered (gdb_stdlog
,
1631 "RC: Not resuming sibling %s (has pending)\n",
1632 target_pid_to_str (lp
->ptid
));
1637 if (debug_linux_nat
)
1638 fprintf_unfiltered (gdb_stdlog
,
1639 "RC: Not resuming sibling %s (not stopped)\n",
1640 target_pid_to_str (lp
->ptid
));
1644 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1645 Resume LWP with the last stop signal, if it is in pass state. */
1648 linux_nat_resume_callback (struct lwp_info
*lp
, void *except
)
1650 enum gdb_signal signo
= GDB_SIGNAL_0
;
1657 struct thread_info
*thread
;
1659 thread
= find_thread_ptid (lp
->ptid
);
1662 signo
= thread
->suspend
.stop_signal
;
1663 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1667 resume_lwp (lp
, 0, signo
);
1672 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1675 lp
->last_resume_kind
= resume_stop
;
1680 resume_set_callback (struct lwp_info
*lp
, void *data
)
1683 lp
->last_resume_kind
= resume_continue
;
1688 linux_nat_target::resume (ptid_t ptid
, int step
, enum gdb_signal signo
)
1690 struct lwp_info
*lp
;
1693 if (debug_linux_nat
)
1694 fprintf_unfiltered (gdb_stdlog
,
1695 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1696 step
? "step" : "resume",
1697 target_pid_to_str (ptid
),
1698 (signo
!= GDB_SIGNAL_0
1699 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1700 target_pid_to_str (inferior_ptid
));
1702 /* A specific PTID means `step only this process id'. */
1703 resume_many
= (minus_one_ptid
== ptid
1706 /* Mark the lwps we're resuming as resumed. */
1707 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1709 /* See if it's the current inferior that should be handled
1712 lp
= find_lwp_pid (inferior_ptid
);
1714 lp
= find_lwp_pid (ptid
);
1715 gdb_assert (lp
!= NULL
);
1717 /* Remember if we're stepping. */
1718 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1720 /* If we have a pending wait status for this thread, there is no
1721 point in resuming the process. But first make sure that
1722 linux_nat_wait won't preemptively handle the event - we
1723 should never take this short-circuit if we are going to
1724 leave LP running, since we have skipped resuming all the
1725 other threads. This bit of code needs to be synchronized
1726 with linux_nat_wait. */
1728 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1731 && WSTOPSIG (lp
->status
)
1732 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1734 if (debug_linux_nat
)
1735 fprintf_unfiltered (gdb_stdlog
,
1736 "LLR: Not short circuiting for ignored "
1737 "status 0x%x\n", lp
->status
);
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
);
1742 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1747 if (lwp_status_pending_p (lp
))
1749 /* FIXME: What should we do if we are supposed to continue
1750 this thread with a signal? */
1751 gdb_assert (signo
== GDB_SIGNAL_0
);
1753 if (debug_linux_nat
)
1754 fprintf_unfiltered (gdb_stdlog
,
1755 "LLR: Short circuiting for status 0x%x\n",
1758 if (target_can_async_p ())
1761 /* Tell the event loop we have something to process. */
1768 iterate_over_lwps (ptid
, linux_nat_resume_callback
, lp
);
1770 if (debug_linux_nat
)
1771 fprintf_unfiltered (gdb_stdlog
,
1772 "LLR: %s %s, %s (resume event thread)\n",
1773 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1774 target_pid_to_str (lp
->ptid
),
1775 (signo
!= GDB_SIGNAL_0
1776 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1778 linux_resume_one_lwp (lp
, step
, signo
);
1780 if (target_can_async_p ())
1784 /* Send a signal to an LWP. */
1787 kill_lwp (int lwpid
, int signo
)
1792 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1793 if (errno
== ENOSYS
)
1795 /* If tkill fails, then we are not using nptl threads, a
1796 configuration we no longer support. */
1797 perror_with_name (("tkill"));
1802 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1803 event, check if the core is interested in it: if not, ignore the
1804 event, and keep waiting; otherwise, we need to toggle the LWP's
1805 syscall entry/exit status, since the ptrace event itself doesn't
1806 indicate it, and report the trap to higher layers. */
1809 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1811 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1812 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1813 thread_info
*thread
= find_thread_ptid (lp
->ptid
);
1814 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, thread
);
1818 /* If we're stopping threads, there's a SIGSTOP pending, which
1819 makes it so that the LWP reports an immediate syscall return,
1820 followed by the SIGSTOP. Skip seeing that "return" using
1821 PTRACE_CONT directly, and let stop_wait_callback collect the
1822 SIGSTOP. Later when the thread is resumed, a new syscall
1823 entry event. If we didn't do this (and returned 0), we'd
1824 leave a syscall entry pending, and our caller, by using
1825 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1826 itself. Later, when the user re-resumes this LWP, we'd see
1827 another syscall entry event and we'd mistake it for a return.
1829 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1830 (leaving immediately with LWP->signalled set, without issuing
1831 a PTRACE_CONT), it would still be problematic to leave this
1832 syscall enter pending, as later when the thread is resumed,
1833 it would then see the same syscall exit mentioned above,
1834 followed by the delayed SIGSTOP, while the syscall didn't
1835 actually get to execute. It seems it would be even more
1836 confusing to the user. */
1838 if (debug_linux_nat
)
1839 fprintf_unfiltered (gdb_stdlog
,
1840 "LHST: ignoring syscall %d "
1841 "for LWP %ld (stopping threads), "
1842 "resuming with PTRACE_CONT for SIGSTOP\n",
1846 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1847 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
1852 /* Always update the entry/return state, even if this particular
1853 syscall isn't interesting to the core now. In async mode,
1854 the user could install a new catchpoint for this syscall
1855 between syscall enter/return, and we'll need to know to
1856 report a syscall return if that happens. */
1857 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1858 ? TARGET_WAITKIND_SYSCALL_RETURN
1859 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1861 if (catch_syscall_enabled ())
1863 if (catching_syscall_number (syscall_number
))
1865 /* Alright, an event to report. */
1866 ourstatus
->kind
= lp
->syscall_state
;
1867 ourstatus
->value
.syscall_number
= syscall_number
;
1869 if (debug_linux_nat
)
1870 fprintf_unfiltered (gdb_stdlog
,
1871 "LHST: stopping for %s of syscall %d"
1874 == TARGET_WAITKIND_SYSCALL_ENTRY
1875 ? "entry" : "return",
1881 if (debug_linux_nat
)
1882 fprintf_unfiltered (gdb_stdlog
,
1883 "LHST: ignoring %s of syscall %d "
1885 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1886 ? "entry" : "return",
1892 /* If we had been syscall tracing, and hence used PT_SYSCALL
1893 before on this LWP, it could happen that the user removes all
1894 syscall catchpoints before we get to process this event.
1895 There are two noteworthy issues here:
1897 - When stopped at a syscall entry event, resuming with
1898 PT_STEP still resumes executing the syscall and reports a
1901 - Only PT_SYSCALL catches syscall enters. If we last
1902 single-stepped this thread, then this event can't be a
1903 syscall enter. If we last single-stepped this thread, this
1904 has to be a syscall exit.
1906 The points above mean that the next resume, be it PT_STEP or
1907 PT_CONTINUE, can not trigger a syscall trace event. */
1908 if (debug_linux_nat
)
1909 fprintf_unfiltered (gdb_stdlog
,
1910 "LHST: caught syscall event "
1911 "with no syscall catchpoints."
1912 " %d for LWP %ld, ignoring\n",
1915 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1918 /* The core isn't interested in this event. For efficiency, avoid
1919 stopping all threads only to have the core resume them all again.
1920 Since we're not stopping threads, if we're still syscall tracing
1921 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1922 subsequent syscall. Simply resume using the inf-ptrace layer,
1923 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1925 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1929 /* Handle a GNU/Linux extended wait response. If we see a clone
1930 event, we need to add the new LWP to our list (and not report the
1931 trap to higher layers). This function returns non-zero if the
1932 event should be ignored and we should wait again. If STOPPING is
1933 true, the new LWP remains stopped, otherwise it is continued. */
1936 linux_handle_extended_wait (struct lwp_info
*lp
, int status
)
1938 int pid
= lp
->ptid
.lwp ();
1939 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1940 int event
= linux_ptrace_get_extended_event (status
);
1942 /* All extended events we currently use are mid-syscall. Only
1943 PTRACE_EVENT_STOP is delivered more like a signal-stop, but
1944 you have to be using PTRACE_SEIZE to get that. */
1945 lp
->syscall_state
= TARGET_WAITKIND_SYSCALL_ENTRY
;
1947 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1948 || event
== PTRACE_EVENT_CLONE
)
1950 unsigned long new_pid
;
1953 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1955 /* If we haven't already seen the new PID stop, wait for it now. */
1956 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1958 /* The new child has a pending SIGSTOP. We can't affect it until it
1959 hits the SIGSTOP, but we're already attached. */
1960 ret
= my_waitpid (new_pid
, &status
, __WALL
);
1962 perror_with_name (_("waiting for new child"));
1963 else if (ret
!= new_pid
)
1964 internal_error (__FILE__
, __LINE__
,
1965 _("wait returned unexpected PID %d"), ret
);
1966 else if (!WIFSTOPPED (status
))
1967 internal_error (__FILE__
, __LINE__
,
1968 _("wait returned unexpected status 0x%x"), status
);
1971 ourstatus
->value
.related_pid
= ptid_t (new_pid
, new_pid
, 0);
1973 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1975 /* The arch-specific native code may need to know about new
1976 forks even if those end up never mapped to an
1978 linux_target
->low_new_fork (lp
, new_pid
);
1981 if (event
== PTRACE_EVENT_FORK
1982 && linux_fork_checkpointing_p (lp
->ptid
.pid ()))
1984 /* Handle checkpointing by linux-fork.c here as a special
1985 case. We don't want the follow-fork-mode or 'catch fork'
1986 to interfere with this. */
1988 /* This won't actually modify the breakpoint list, but will
1989 physically remove the breakpoints from the child. */
1990 detach_breakpoints (ptid_t (new_pid
, new_pid
, 0));
1992 /* Retain child fork in ptrace (stopped) state. */
1993 if (!find_fork_pid (new_pid
))
1996 /* Report as spurious, so that infrun doesn't want to follow
1997 this fork. We're actually doing an infcall in
1999 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
2001 /* Report the stop to the core. */
2005 if (event
== PTRACE_EVENT_FORK
)
2006 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2007 else if (event
== PTRACE_EVENT_VFORK
)
2008 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2009 else if (event
== PTRACE_EVENT_CLONE
)
2011 struct lwp_info
*new_lp
;
2013 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2015 if (debug_linux_nat
)
2016 fprintf_unfiltered (gdb_stdlog
,
2017 "LHEW: Got clone event "
2018 "from LWP %d, new child is LWP %ld\n",
2021 new_lp
= add_lwp (ptid_t (lp
->ptid
.pid (), new_pid
, 0));
2022 new_lp
->stopped
= 1;
2023 new_lp
->resumed
= 1;
2025 /* If the thread_db layer is active, let it record the user
2026 level thread id and status, and add the thread to GDB's
2028 if (!thread_db_notice_clone (lp
->ptid
, new_lp
->ptid
))
2030 /* The process is not using thread_db. Add the LWP to
2032 target_post_attach (new_lp
->ptid
.lwp ());
2033 add_thread (new_lp
->ptid
);
2036 /* Even if we're stopping the thread for some reason
2037 internal to this module, from the perspective of infrun
2038 and the user/frontend, this new thread is running until
2039 it next reports a stop. */
2040 set_running (new_lp
->ptid
, 1);
2041 set_executing (new_lp
->ptid
, 1);
2043 if (WSTOPSIG (status
) != SIGSTOP
)
2045 /* This can happen if someone starts sending signals to
2046 the new thread before it gets a chance to run, which
2047 have a lower number than SIGSTOP (e.g. SIGUSR1).
2048 This is an unlikely case, and harder to handle for
2049 fork / vfork than for clone, so we do not try - but
2050 we handle it for clone events here. */
2052 new_lp
->signalled
= 1;
2054 /* We created NEW_LP so it cannot yet contain STATUS. */
2055 gdb_assert (new_lp
->status
== 0);
2057 /* Save the wait status to report later. */
2058 if (debug_linux_nat
)
2059 fprintf_unfiltered (gdb_stdlog
,
2060 "LHEW: waitpid of new LWP %ld, "
2061 "saving status %s\n",
2062 (long) new_lp
->ptid
.lwp (),
2063 status_to_str (status
));
2064 new_lp
->status
= status
;
2066 else if (report_thread_events
)
2068 new_lp
->waitstatus
.kind
= TARGET_WAITKIND_THREAD_CREATED
;
2069 new_lp
->status
= status
;
2078 if (event
== PTRACE_EVENT_EXEC
)
2080 if (debug_linux_nat
)
2081 fprintf_unfiltered (gdb_stdlog
,
2082 "LHEW: Got exec event from LWP %ld\n",
2085 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2086 ourstatus
->value
.execd_pathname
2087 = xstrdup (linux_proc_pid_to_exec_file (pid
));
2089 /* The thread that execed must have been resumed, but, when a
2090 thread execs, it changes its tid to the tgid, and the old
2091 tgid thread might have not been resumed. */
2096 if (event
== PTRACE_EVENT_VFORK_DONE
)
2098 if (current_inferior ()->waiting_for_vfork_done
)
2100 if (debug_linux_nat
)
2101 fprintf_unfiltered (gdb_stdlog
,
2102 "LHEW: Got expected PTRACE_EVENT_"
2103 "VFORK_DONE from LWP %ld: stopping\n",
2106 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2110 if (debug_linux_nat
)
2111 fprintf_unfiltered (gdb_stdlog
,
2112 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2113 "from LWP %ld: ignoring\n",
2118 internal_error (__FILE__
, __LINE__
,
2119 _("unknown ptrace event %d"), event
);
2122 /* Suspend waiting for a signal. We're mostly interested in
2128 if (debug_linux_nat
)
2129 fprintf_unfiltered (gdb_stdlog
, "linux-nat: about to sigsuspend\n");
2130 sigsuspend (&suspend_mask
);
2132 /* If the quit flag is set, it means that the user pressed Ctrl-C
2133 and we're debugging a process that is running on a separate
2134 terminal, so we must forward the Ctrl-C to the inferior. (If the
2135 inferior is sharing GDB's terminal, then the Ctrl-C reaches the
2136 inferior directly.) We must do this here because functions that
2137 need to block waiting for a signal loop forever until there's an
2138 event to report before returning back to the event loop. */
2139 if (!target_terminal::is_ours ())
2141 if (check_quit_flag ())
2142 target_pass_ctrlc ();
2146 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2150 wait_lwp (struct lwp_info
*lp
)
2154 int thread_dead
= 0;
2157 gdb_assert (!lp
->stopped
);
2158 gdb_assert (lp
->status
== 0);
2160 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2161 block_child_signals (&prev_mask
);
2165 pid
= my_waitpid (lp
->ptid
.lwp (), &status
, __WALL
| WNOHANG
);
2166 if (pid
== -1 && errno
== ECHILD
)
2168 /* The thread has previously exited. We need to delete it
2169 now because if this was a non-leader thread execing, we
2170 won't get an exit event. See comments on exec events at
2171 the top of the file. */
2173 if (debug_linux_nat
)
2174 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2175 target_pid_to_str (lp
->ptid
));
2180 /* Bugs 10970, 12702.
2181 Thread group leader may have exited in which case we'll lock up in
2182 waitpid if there are other threads, even if they are all zombies too.
2183 Basically, we're not supposed to use waitpid this way.
2184 tkill(pid,0) cannot be used here as it gets ESRCH for both
2185 for zombie and running processes.
2187 As a workaround, check if we're waiting for the thread group leader and
2188 if it's a zombie, and avoid calling waitpid if it is.
2190 This is racy, what if the tgl becomes a zombie right after we check?
2191 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2192 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2194 if (lp
->ptid
.pid () == lp
->ptid
.lwp ()
2195 && linux_proc_pid_is_zombie (lp
->ptid
.lwp ()))
2198 if (debug_linux_nat
)
2199 fprintf_unfiltered (gdb_stdlog
,
2200 "WL: Thread group leader %s vanished.\n",
2201 target_pid_to_str (lp
->ptid
));
2205 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2206 get invoked despite our caller had them intentionally blocked by
2207 block_child_signals. This is sensitive only to the loop of
2208 linux_nat_wait_1 and there if we get called my_waitpid gets called
2209 again before it gets to sigsuspend so we can safely let the handlers
2210 get executed here. */
2214 restore_child_signals_mask (&prev_mask
);
2218 gdb_assert (pid
== lp
->ptid
.lwp ());
2220 if (debug_linux_nat
)
2222 fprintf_unfiltered (gdb_stdlog
,
2223 "WL: waitpid %s received %s\n",
2224 target_pid_to_str (lp
->ptid
),
2225 status_to_str (status
));
2228 /* Check if the thread has exited. */
2229 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2231 if (report_thread_events
2232 || lp
->ptid
.pid () == lp
->ptid
.lwp ())
2234 if (debug_linux_nat
)
2235 fprintf_unfiltered (gdb_stdlog
, "WL: LWP %d exited.\n",
2238 /* If this is the leader exiting, it means the whole
2239 process is gone. Store the status to report to the
2240 core. Store it in lp->waitstatus, because lp->status
2241 would be ambiguous (W_EXITCODE(0,0) == 0). */
2242 store_waitstatus (&lp
->waitstatus
, status
);
2247 if (debug_linux_nat
)
2248 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2249 target_pid_to_str (lp
->ptid
));
2259 gdb_assert (WIFSTOPPED (status
));
2262 if (lp
->must_set_ptrace_flags
)
2264 struct inferior
*inf
= find_inferior_pid (lp
->ptid
.pid ());
2265 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2267 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2268 lp
->must_set_ptrace_flags
= 0;
2271 /* Handle GNU/Linux's syscall SIGTRAPs. */
2272 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2274 /* No longer need the sysgood bit. The ptrace event ends up
2275 recorded in lp->waitstatus if we care for it. We can carry
2276 on handling the event like a regular SIGTRAP from here
2278 status
= W_STOPCODE (SIGTRAP
);
2279 if (linux_handle_syscall_trap (lp
, 1))
2280 return wait_lwp (lp
);
2284 /* Almost all other ptrace-stops are known to be outside of system
2285 calls, with further exceptions in linux_handle_extended_wait. */
2286 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
2289 /* Handle GNU/Linux's extended waitstatus for trace events. */
2290 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2291 && linux_is_extended_waitstatus (status
))
2293 if (debug_linux_nat
)
2294 fprintf_unfiltered (gdb_stdlog
,
2295 "WL: Handling extended status 0x%06x\n",
2297 linux_handle_extended_wait (lp
, status
);
2304 /* Send a SIGSTOP to LP. */
2307 stop_callback (struct lwp_info
*lp
, void *data
)
2309 if (!lp
->stopped
&& !lp
->signalled
)
2313 if (debug_linux_nat
)
2315 fprintf_unfiltered (gdb_stdlog
,
2316 "SC: kill %s **<SIGSTOP>**\n",
2317 target_pid_to_str (lp
->ptid
));
2320 ret
= kill_lwp (lp
->ptid
.lwp (), SIGSTOP
);
2321 if (debug_linux_nat
)
2323 fprintf_unfiltered (gdb_stdlog
,
2324 "SC: lwp kill %d %s\n",
2326 errno
? safe_strerror (errno
) : "ERRNO-OK");
2330 gdb_assert (lp
->status
== 0);
2336 /* Request a stop on LWP. */
2339 linux_stop_lwp (struct lwp_info
*lwp
)
2341 stop_callback (lwp
, NULL
);
2344 /* See linux-nat.h */
2347 linux_stop_and_wait_all_lwps (void)
2349 /* Stop all LWP's ... */
2350 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
2352 /* ... and wait until all of them have reported back that
2353 they're no longer running. */
2354 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
2357 /* See linux-nat.h */
2360 linux_unstop_all_lwps (void)
2362 iterate_over_lwps (minus_one_ptid
,
2363 resume_stopped_resumed_lwps
, &minus_one_ptid
);
2366 /* Return non-zero if LWP PID has a pending SIGINT. */
2369 linux_nat_has_pending_sigint (int pid
)
2371 sigset_t pending
, blocked
, ignored
;
2373 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2375 if (sigismember (&pending
, SIGINT
)
2376 && !sigismember (&ignored
, SIGINT
))
2382 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2385 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2387 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2388 flag to consume the next one. */
2389 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2390 && WSTOPSIG (lp
->status
) == SIGINT
)
2393 lp
->ignore_sigint
= 1;
2398 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2399 This function is called after we know the LWP has stopped; if the LWP
2400 stopped before the expected SIGINT was delivered, then it will never have
2401 arrived. Also, if the signal was delivered to a shared queue and consumed
2402 by a different thread, it will never be delivered to this LWP. */
2405 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2407 if (!lp
->ignore_sigint
)
2410 if (!linux_nat_has_pending_sigint (lp
->ptid
.lwp ()))
2412 if (debug_linux_nat
)
2413 fprintf_unfiltered (gdb_stdlog
,
2414 "MCIS: Clearing bogus flag for %s\n",
2415 target_pid_to_str (lp
->ptid
));
2416 lp
->ignore_sigint
= 0;
2420 /* Fetch the possible triggered data watchpoint info and store it in
2423 On some archs, like x86, that use debug registers to set
2424 watchpoints, it's possible that the way to know which watched
2425 address trapped, is to check the register that is used to select
2426 which address to watch. Problem is, between setting the watchpoint
2427 and reading back which data address trapped, the user may change
2428 the set of watchpoints, and, as a consequence, GDB changes the
2429 debug registers in the inferior. To avoid reading back a stale
2430 stopped-data-address when that happens, we cache in LP the fact
2431 that a watchpoint trapped, and the corresponding data address, as
2432 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2433 registers meanwhile, we have the cached data we can rely on. */
2436 check_stopped_by_watchpoint (struct lwp_info
*lp
)
2438 scoped_restore save_inferior_ptid
= make_scoped_restore (&inferior_ptid
);
2439 inferior_ptid
= lp
->ptid
;
2441 if (linux_target
->low_stopped_by_watchpoint ())
2443 lp
->stop_reason
= TARGET_STOPPED_BY_WATCHPOINT
;
2444 lp
->stopped_data_address_p
2445 = linux_target
->low_stopped_data_address (&lp
->stopped_data_address
);
2448 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2451 /* Returns true if the LWP had stopped for a watchpoint. */
2454 linux_nat_target::stopped_by_watchpoint ()
2456 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2458 gdb_assert (lp
!= NULL
);
2460 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2464 linux_nat_target::stopped_data_address (CORE_ADDR
*addr_p
)
2466 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2468 gdb_assert (lp
!= NULL
);
2470 *addr_p
= lp
->stopped_data_address
;
2472 return lp
->stopped_data_address_p
;
2475 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2478 linux_nat_target::low_status_is_event (int status
)
2480 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2483 /* Wait until LP is stopped. */
2486 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2488 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
2490 /* If this is a vfork parent, bail out, it is not going to report
2491 any SIGSTOP until the vfork is done with. */
2492 if (inf
->vfork_child
!= NULL
)
2499 status
= wait_lwp (lp
);
2503 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2504 && WSTOPSIG (status
) == SIGINT
)
2506 lp
->ignore_sigint
= 0;
2509 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
2511 if (debug_linux_nat
)
2512 fprintf_unfiltered (gdb_stdlog
,
2513 "PTRACE_CONT %s, 0, 0 (%s) "
2514 "(discarding SIGINT)\n",
2515 target_pid_to_str (lp
->ptid
),
2516 errno
? safe_strerror (errno
) : "OK");
2518 return stop_wait_callback (lp
, NULL
);
2521 maybe_clear_ignore_sigint (lp
);
2523 if (WSTOPSIG (status
) != SIGSTOP
)
2525 /* The thread was stopped with a signal other than SIGSTOP. */
2527 if (debug_linux_nat
)
2528 fprintf_unfiltered (gdb_stdlog
,
2529 "SWC: Pending event %s in %s\n",
2530 status_to_str ((int) status
),
2531 target_pid_to_str (lp
->ptid
));
2533 /* Save the sigtrap event. */
2534 lp
->status
= status
;
2535 gdb_assert (lp
->signalled
);
2536 save_stop_reason (lp
);
2540 /* We caught the SIGSTOP that we intended to catch. */
2542 if (debug_linux_nat
)
2543 fprintf_unfiltered (gdb_stdlog
,
2544 "SWC: Expected SIGSTOP caught for %s.\n",
2545 target_pid_to_str (lp
->ptid
));
2549 /* If we are waiting for this stop so we can report the thread
2550 stopped then we need to record this status. Otherwise, we can
2551 now discard this stop event. */
2552 if (lp
->last_resume_kind
== resume_stop
)
2554 lp
->status
= status
;
2555 save_stop_reason (lp
);
2563 /* Return non-zero if LP has a wait status pending. Discard the
2564 pending event and resume the LWP if the event that originally
2565 caused the stop became uninteresting. */
2568 status_callback (struct lwp_info
*lp
, void *data
)
2570 /* Only report a pending wait status if we pretend that this has
2571 indeed been resumed. */
2575 if (!lwp_status_pending_p (lp
))
2578 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
2579 || lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2581 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2585 pc
= regcache_read_pc (regcache
);
2587 if (pc
!= lp
->stop_pc
)
2589 if (debug_linux_nat
)
2590 fprintf_unfiltered (gdb_stdlog
,
2591 "SC: PC of %s changed. was=%s, now=%s\n",
2592 target_pid_to_str (lp
->ptid
),
2593 paddress (target_gdbarch (), lp
->stop_pc
),
2594 paddress (target_gdbarch (), pc
));
2598 #if !USE_SIGTRAP_SIGINFO
2599 else if (!breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2601 if (debug_linux_nat
)
2602 fprintf_unfiltered (gdb_stdlog
,
2603 "SC: previous breakpoint of %s, at %s gone\n",
2604 target_pid_to_str (lp
->ptid
),
2605 paddress (target_gdbarch (), lp
->stop_pc
));
2613 if (debug_linux_nat
)
2614 fprintf_unfiltered (gdb_stdlog
,
2615 "SC: pending event of %s cancelled.\n",
2616 target_pid_to_str (lp
->ptid
));
2619 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2627 /* Count the LWP's that have had events. */
2630 count_events_callback (struct lwp_info
*lp
, void *data
)
2632 int *count
= (int *) data
;
2634 gdb_assert (count
!= NULL
);
2636 /* Select only resumed LWPs that have an event pending. */
2637 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2643 /* Select the LWP (if any) that is currently being single-stepped. */
2646 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2648 if (lp
->last_resume_kind
== resume_step
2655 /* Returns true if LP has a status pending. */
2658 lwp_status_pending_p (struct lwp_info
*lp
)
2660 /* We check for lp->waitstatus in addition to lp->status, because we
2661 can have pending process exits recorded in lp->status and
2662 W_EXITCODE(0,0) happens to be 0. */
2663 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2666 /* Select the Nth LWP that has had an event. */
2669 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2671 int *selector
= (int *) data
;
2673 gdb_assert (selector
!= NULL
);
2675 /* Select only resumed LWPs that have an event pending. */
2676 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2677 if ((*selector
)-- == 0)
2683 /* Called when the LWP stopped for a signal/trap. If it stopped for a
2684 trap check what caused it (breakpoint, watchpoint, trace, etc.),
2685 and save the result in the LWP's stop_reason field. If it stopped
2686 for a breakpoint, decrement the PC if necessary on the lwp's
2690 save_stop_reason (struct lwp_info
*lp
)
2692 struct regcache
*regcache
;
2693 struct gdbarch
*gdbarch
;
2696 #if USE_SIGTRAP_SIGINFO
2700 gdb_assert (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
);
2701 gdb_assert (lp
->status
!= 0);
2703 if (!linux_target
->low_status_is_event (lp
->status
))
2706 regcache
= get_thread_regcache (lp
->ptid
);
2707 gdbarch
= regcache
->arch ();
2709 pc
= regcache_read_pc (regcache
);
2710 sw_bp_pc
= pc
- gdbarch_decr_pc_after_break (gdbarch
);
2712 #if USE_SIGTRAP_SIGINFO
2713 if (linux_nat_get_siginfo (lp
->ptid
, &siginfo
))
2715 if (siginfo
.si_signo
== SIGTRAP
)
2717 if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
)
2718 && GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2720 /* The si_code is ambiguous on this arch -- check debug
2722 if (!check_stopped_by_watchpoint (lp
))
2723 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2725 else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
))
2727 /* If we determine the LWP stopped for a SW breakpoint,
2728 trust it. Particularly don't check watchpoint
2729 registers, because at least on s390, we'd find
2730 stopped-by-watchpoint as long as there's a watchpoint
2732 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2734 else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2736 /* This can indicate either a hardware breakpoint or
2737 hardware watchpoint. Check debug registers. */
2738 if (!check_stopped_by_watchpoint (lp
))
2739 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2741 else if (siginfo
.si_code
== TRAP_TRACE
)
2743 if (debug_linux_nat
)
2744 fprintf_unfiltered (gdb_stdlog
,
2745 "CSBB: %s stopped by trace\n",
2746 target_pid_to_str (lp
->ptid
));
2748 /* We may have single stepped an instruction that
2749 triggered a watchpoint. In that case, on some
2750 architectures (such as x86), instead of TRAP_HWBKPT,
2751 si_code indicates TRAP_TRACE, and we need to check
2752 the debug registers separately. */
2753 check_stopped_by_watchpoint (lp
);
2758 if ((!lp
->step
|| lp
->stop_pc
== sw_bp_pc
)
2759 && software_breakpoint_inserted_here_p (regcache
->aspace (),
2762 /* The LWP was either continued, or stepped a software
2763 breakpoint instruction. */
2764 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2767 if (hardware_breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2768 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2770 if (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
)
2771 check_stopped_by_watchpoint (lp
);
2774 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
)
2776 if (debug_linux_nat
)
2777 fprintf_unfiltered (gdb_stdlog
,
2778 "CSBB: %s stopped by software breakpoint\n",
2779 target_pid_to_str (lp
->ptid
));
2781 /* Back up the PC if necessary. */
2783 regcache_write_pc (regcache
, sw_bp_pc
);
2785 /* Update this so we record the correct stop PC below. */
2788 else if (lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2790 if (debug_linux_nat
)
2791 fprintf_unfiltered (gdb_stdlog
,
2792 "CSBB: %s stopped by hardware breakpoint\n",
2793 target_pid_to_str (lp
->ptid
));
2795 else if (lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
)
2797 if (debug_linux_nat
)
2798 fprintf_unfiltered (gdb_stdlog
,
2799 "CSBB: %s stopped by hardware watchpoint\n",
2800 target_pid_to_str (lp
->ptid
));
2807 /* Returns true if the LWP had stopped for a software breakpoint. */
2810 linux_nat_target::stopped_by_sw_breakpoint ()
2812 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2814 gdb_assert (lp
!= NULL
);
2816 return lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
;
2819 /* Implement the supports_stopped_by_sw_breakpoint method. */
2822 linux_nat_target::supports_stopped_by_sw_breakpoint ()
2824 return USE_SIGTRAP_SIGINFO
;
2827 /* Returns true if the LWP had stopped for a hardware
2828 breakpoint/watchpoint. */
2831 linux_nat_target::stopped_by_hw_breakpoint ()
2833 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2835 gdb_assert (lp
!= NULL
);
2837 return lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
;
2840 /* Implement the supports_stopped_by_hw_breakpoint method. */
2843 linux_nat_target::supports_stopped_by_hw_breakpoint ()
2845 return USE_SIGTRAP_SIGINFO
;
2848 /* Select one LWP out of those that have events pending. */
2851 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2854 int random_selector
;
2855 struct lwp_info
*event_lp
= NULL
;
2857 /* Record the wait status for the original LWP. */
2858 (*orig_lp
)->status
= *status
;
2860 /* In all-stop, give preference to the LWP that is being
2861 single-stepped. There will be at most one, and it will be the
2862 LWP that the core is most interested in. If we didn't do this,
2863 then we'd have to handle pending step SIGTRAPs somehow in case
2864 the core later continues the previously-stepped thread, as
2865 otherwise we'd report the pending SIGTRAP then, and the core, not
2866 having stepped the thread, wouldn't understand what the trap was
2867 for, and therefore would report it to the user as a random
2869 if (!target_is_non_stop_p ())
2871 event_lp
= iterate_over_lwps (filter
,
2872 select_singlestep_lwp_callback
, NULL
);
2873 if (event_lp
!= NULL
)
2875 if (debug_linux_nat
)
2876 fprintf_unfiltered (gdb_stdlog
,
2877 "SEL: Select single-step %s\n",
2878 target_pid_to_str (event_lp
->ptid
));
2882 if (event_lp
== NULL
)
2884 /* Pick one at random, out of those which have had events. */
2886 /* First see how many events we have. */
2887 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2888 gdb_assert (num_events
> 0);
2890 /* Now randomly pick a LWP out of those that have had
2892 random_selector
= (int)
2893 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2895 if (debug_linux_nat
&& num_events
> 1)
2896 fprintf_unfiltered (gdb_stdlog
,
2897 "SEL: Found %d events, selecting #%d\n",
2898 num_events
, random_selector
);
2900 event_lp
= iterate_over_lwps (filter
,
2901 select_event_lwp_callback
,
2905 if (event_lp
!= NULL
)
2907 /* Switch the event LWP. */
2908 *orig_lp
= event_lp
;
2909 *status
= event_lp
->status
;
2912 /* Flush the wait status for the event LWP. */
2913 (*orig_lp
)->status
= 0;
2916 /* Return non-zero if LP has been resumed. */
2919 resumed_callback (struct lwp_info
*lp
, void *data
)
2924 /* Check if we should go on and pass this event to common code.
2925 Return the affected lwp if we are, or NULL otherwise. */
2927 static struct lwp_info
*
2928 linux_nat_filter_event (int lwpid
, int status
)
2930 struct lwp_info
*lp
;
2931 int event
= linux_ptrace_get_extended_event (status
);
2933 lp
= find_lwp_pid (ptid_t (lwpid
));
2935 /* Check for stop events reported by a process we didn't already
2936 know about - anything not already in our LWP list.
2938 If we're expecting to receive stopped processes after
2939 fork, vfork, and clone events, then we'll just add the
2940 new one to our list and go back to waiting for the event
2941 to be reported - the stopped process might be returned
2942 from waitpid before or after the event is.
2944 But note the case of a non-leader thread exec'ing after the
2945 leader having exited, and gone from our lists. The non-leader
2946 thread changes its tid to the tgid. */
2948 if (WIFSTOPPED (status
) && lp
== NULL
2949 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2951 /* A multi-thread exec after we had seen the leader exiting. */
2952 if (debug_linux_nat
)
2953 fprintf_unfiltered (gdb_stdlog
,
2954 "LLW: Re-adding thread group leader LWP %d.\n",
2957 lp
= add_lwp (ptid_t (lwpid
, lwpid
, 0));
2960 add_thread (lp
->ptid
);
2963 if (WIFSTOPPED (status
) && !lp
)
2965 if (debug_linux_nat
)
2966 fprintf_unfiltered (gdb_stdlog
,
2967 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2968 (long) lwpid
, status_to_str (status
));
2969 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2973 /* Make sure we don't report an event for the exit of an LWP not in
2974 our list, i.e. not part of the current process. This can happen
2975 if we detach from a program we originally forked and then it
2977 if (!WIFSTOPPED (status
) && !lp
)
2980 /* This LWP is stopped now. (And if dead, this prevents it from
2981 ever being continued.) */
2984 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2986 struct inferior
*inf
= find_inferior_pid (lp
->ptid
.pid ());
2987 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2989 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2990 lp
->must_set_ptrace_flags
= 0;
2993 /* Handle GNU/Linux's syscall SIGTRAPs. */
2994 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2996 /* No longer need the sysgood bit. The ptrace event ends up
2997 recorded in lp->waitstatus if we care for it. We can carry
2998 on handling the event like a regular SIGTRAP from here
3000 status
= W_STOPCODE (SIGTRAP
);
3001 if (linux_handle_syscall_trap (lp
, 0))
3006 /* Almost all other ptrace-stops are known to be outside of system
3007 calls, with further exceptions in linux_handle_extended_wait. */
3008 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
3011 /* Handle GNU/Linux's extended waitstatus for trace events. */
3012 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
3013 && linux_is_extended_waitstatus (status
))
3015 if (debug_linux_nat
)
3016 fprintf_unfiltered (gdb_stdlog
,
3017 "LLW: Handling extended status 0x%06x\n",
3019 if (linux_handle_extended_wait (lp
, status
))
3023 /* Check if the thread has exited. */
3024 if (WIFEXITED (status
) || WIFSIGNALED (status
))
3026 if (!report_thread_events
3027 && num_lwps (lp
->ptid
.pid ()) > 1)
3029 if (debug_linux_nat
)
3030 fprintf_unfiltered (gdb_stdlog
,
3031 "LLW: %s exited.\n",
3032 target_pid_to_str (lp
->ptid
));
3034 /* If there is at least one more LWP, then the exit signal
3035 was not the end of the debugged application and should be
3041 /* Note that even if the leader was ptrace-stopped, it can still
3042 exit, if e.g., some other thread brings down the whole
3043 process (calls `exit'). So don't assert that the lwp is
3045 if (debug_linux_nat
)
3046 fprintf_unfiltered (gdb_stdlog
,
3047 "LWP %ld exited (resumed=%d)\n",
3048 lp
->ptid
.lwp (), lp
->resumed
);
3050 /* Dead LWP's aren't expected to reported a pending sigstop. */
3053 /* Store the pending event in the waitstatus, because
3054 W_EXITCODE(0,0) == 0. */
3055 store_waitstatus (&lp
->waitstatus
, status
);
3059 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3060 an attempt to stop an LWP. */
3062 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3066 if (lp
->last_resume_kind
== resume_stop
)
3068 if (debug_linux_nat
)
3069 fprintf_unfiltered (gdb_stdlog
,
3070 "LLW: resume_stop SIGSTOP caught for %s.\n",
3071 target_pid_to_str (lp
->ptid
));
3075 /* This is a delayed SIGSTOP. Filter out the event. */
3077 if (debug_linux_nat
)
3078 fprintf_unfiltered (gdb_stdlog
,
3079 "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
3081 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3082 target_pid_to_str (lp
->ptid
));
3084 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3085 gdb_assert (lp
->resumed
);
3090 /* Make sure we don't report a SIGINT that we have already displayed
3091 for another thread. */
3092 if (lp
->ignore_sigint
3093 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3095 if (debug_linux_nat
)
3096 fprintf_unfiltered (gdb_stdlog
,
3097 "LLW: Delayed SIGINT caught for %s.\n",
3098 target_pid_to_str (lp
->ptid
));
3100 /* This is a delayed SIGINT. */
3101 lp
->ignore_sigint
= 0;
3103 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3104 if (debug_linux_nat
)
3105 fprintf_unfiltered (gdb_stdlog
,
3106 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3108 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3109 target_pid_to_str (lp
->ptid
));
3110 gdb_assert (lp
->resumed
);
3112 /* Discard the event. */
3116 /* Don't report signals that GDB isn't interested in, such as
3117 signals that are neither printed nor stopped upon. Stopping all
3118 threads can be a bit time-consuming so if we want decent
3119 performance with heavily multi-threaded programs, especially when
3120 they're using a high frequency timer, we'd better avoid it if we
3122 if (WIFSTOPPED (status
))
3124 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3126 if (!target_is_non_stop_p ())
3128 /* Only do the below in all-stop, as we currently use SIGSTOP
3129 to implement target_stop (see linux_nat_stop) in
3131 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3133 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3134 forwarded to the entire process group, that is, all LWPs
3135 will receive it - unless they're using CLONE_THREAD to
3136 share signals. Since we only want to report it once, we
3137 mark it as ignored for all LWPs except this one. */
3138 iterate_over_lwps (ptid_t (lp
->ptid
.pid ()),
3139 set_ignore_sigint
, NULL
);
3140 lp
->ignore_sigint
= 0;
3143 maybe_clear_ignore_sigint (lp
);
3146 /* When using hardware single-step, we need to report every signal.
3147 Otherwise, signals in pass_mask may be short-circuited
3148 except signals that might be caused by a breakpoint. */
3150 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
))
3151 && !linux_wstatus_maybe_breakpoint (status
))
3153 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3154 if (debug_linux_nat
)
3155 fprintf_unfiltered (gdb_stdlog
,
3156 "LLW: %s %s, %s (preempt 'handle')\n",
3158 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3159 target_pid_to_str (lp
->ptid
),
3160 (signo
!= GDB_SIGNAL_0
3161 ? strsignal (gdb_signal_to_host (signo
))
3167 /* An interesting event. */
3169 lp
->status
= status
;
3170 save_stop_reason (lp
);
3174 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3175 their exits until all other threads in the group have exited. */
3178 check_zombie_leaders (void)
3180 for (inferior
*inf
: all_inferiors ())
3182 struct lwp_info
*leader_lp
;
3187 leader_lp
= find_lwp_pid (ptid_t (inf
->pid
));
3188 if (leader_lp
!= NULL
3189 /* Check if there are other threads in the group, as we may
3190 have raced with the inferior simply exiting. */
3191 && num_lwps (inf
->pid
) > 1
3192 && linux_proc_pid_is_zombie (inf
->pid
))
3194 if (debug_linux_nat
)
3195 fprintf_unfiltered (gdb_stdlog
,
3196 "CZL: Thread group leader %d zombie "
3197 "(it exited, or another thread execd).\n",
3200 /* A leader zombie can mean one of two things:
3202 - It exited, and there's an exit status pending
3203 available, or only the leader exited (not the whole
3204 program). In the latter case, we can't waitpid the
3205 leader's exit status until all other threads are gone.
3207 - There are 3 or more threads in the group, and a thread
3208 other than the leader exec'd. See comments on exec
3209 events at the top of the file. We could try
3210 distinguishing the exit and exec cases, by waiting once
3211 more, and seeing if something comes out, but it doesn't
3212 sound useful. The previous leader _does_ go away, and
3213 we'll re-add the new one once we see the exec event
3214 (which is just the same as what would happen if the
3215 previous leader did exit voluntarily before some other
3218 if (debug_linux_nat
)
3219 fprintf_unfiltered (gdb_stdlog
,
3220 "CZL: Thread group leader %d vanished.\n",
3222 exit_lwp (leader_lp
);
3227 /* Convenience function that is called when the kernel reports an exit
3228 event. This decides whether to report the event to GDB as a
3229 process exit event, a thread exit event, or to suppress the
3233 filter_exit_event (struct lwp_info
*event_child
,
3234 struct target_waitstatus
*ourstatus
)
3236 ptid_t ptid
= event_child
->ptid
;
3238 if (num_lwps (ptid
.pid ()) > 1)
3240 if (report_thread_events
)
3241 ourstatus
->kind
= TARGET_WAITKIND_THREAD_EXITED
;
3243 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3245 exit_lwp (event_child
);
3252 linux_nat_wait_1 (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3256 enum resume_kind last_resume_kind
;
3257 struct lwp_info
*lp
;
3260 if (debug_linux_nat
)
3261 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3263 /* The first time we get here after starting a new inferior, we may
3264 not have added it to the LWP list yet - this is the earliest
3265 moment at which we know its PID. */
3266 if (inferior_ptid
.is_pid ())
3268 /* Upgrade the main thread's ptid. */
3269 thread_change_ptid (inferior_ptid
,
3270 ptid_t (inferior_ptid
.pid (),
3271 inferior_ptid
.pid (), 0));
3273 lp
= add_initial_lwp (inferior_ptid
);
3277 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3278 block_child_signals (&prev_mask
);
3280 /* First check if there is a LWP with a wait status pending. */
3281 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3284 if (debug_linux_nat
)
3285 fprintf_unfiltered (gdb_stdlog
,
3286 "LLW: Using pending wait status %s for %s.\n",
3287 status_to_str (lp
->status
),
3288 target_pid_to_str (lp
->ptid
));
3291 /* But if we don't find a pending event, we'll have to wait. Always
3292 pull all events out of the kernel. We'll randomly select an
3293 event LWP out of all that have events, to prevent starvation. */
3299 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3302 - If the thread group leader exits while other threads in the
3303 thread group still exist, waitpid(TGID, ...) hangs. That
3304 waitpid won't return an exit status until the other threads
3305 in the group are reapped.
3307 - When a non-leader thread execs, that thread just vanishes
3308 without reporting an exit (so we'd hang if we waited for it
3309 explicitly in that case). The exec event is reported to
3313 lwpid
= my_waitpid (-1, &status
, __WALL
| WNOHANG
);
3315 if (debug_linux_nat
)
3316 fprintf_unfiltered (gdb_stdlog
,
3317 "LNW: waitpid(-1, ...) returned %d, %s\n",
3318 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3322 if (debug_linux_nat
)
3324 fprintf_unfiltered (gdb_stdlog
,
3325 "LLW: waitpid %ld received %s\n",
3326 (long) lwpid
, status_to_str (status
));
3329 linux_nat_filter_event (lwpid
, status
);
3330 /* Retry until nothing comes out of waitpid. A single
3331 SIGCHLD can indicate more than one child stopped. */
3335 /* Now that we've pulled all events out of the kernel, resume
3336 LWPs that don't have an interesting event to report. */
3337 iterate_over_lwps (minus_one_ptid
,
3338 resume_stopped_resumed_lwps
, &minus_one_ptid
);
3340 /* ... and find an LWP with a status to report to the core, if
3342 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3346 /* Check for zombie thread group leaders. Those can't be reaped
3347 until all other threads in the thread group are. */
3348 check_zombie_leaders ();
3350 /* If there are no resumed children left, bail. We'd be stuck
3351 forever in the sigsuspend call below otherwise. */
3352 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3354 if (debug_linux_nat
)
3355 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3357 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3359 restore_child_signals_mask (&prev_mask
);
3360 return minus_one_ptid
;
3363 /* No interesting event to report to the core. */
3365 if (target_options
& TARGET_WNOHANG
)
3367 if (debug_linux_nat
)
3368 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3370 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3371 restore_child_signals_mask (&prev_mask
);
3372 return minus_one_ptid
;
3375 /* We shouldn't end up here unless we want to try again. */
3376 gdb_assert (lp
== NULL
);
3378 /* Block until we get an event reported with SIGCHLD. */
3384 status
= lp
->status
;
3387 if (!target_is_non_stop_p ())
3389 /* Now stop all other LWP's ... */
3390 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3392 /* ... and wait until all of them have reported back that
3393 they're no longer running. */
3394 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3397 /* If we're not waiting for a specific LWP, choose an event LWP from
3398 among those that have had events. Giving equal priority to all
3399 LWPs that have had events helps prevent starvation. */
3400 if (ptid
== minus_one_ptid
|| ptid
.is_pid ())
3401 select_event_lwp (ptid
, &lp
, &status
);
3403 gdb_assert (lp
!= NULL
);
3405 /* Now that we've selected our final event LWP, un-adjust its PC if
3406 it was a software breakpoint, and we can't reliably support the
3407 "stopped by software breakpoint" stop reason. */
3408 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
3409 && !USE_SIGTRAP_SIGINFO
)
3411 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3412 struct gdbarch
*gdbarch
= regcache
->arch ();
3413 int decr_pc
= gdbarch_decr_pc_after_break (gdbarch
);
3419 pc
= regcache_read_pc (regcache
);
3420 regcache_write_pc (regcache
, pc
+ decr_pc
);
3424 /* We'll need this to determine whether to report a SIGSTOP as
3425 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3427 last_resume_kind
= lp
->last_resume_kind
;
3429 if (!target_is_non_stop_p ())
3431 /* In all-stop, from the core's perspective, all LWPs are now
3432 stopped until a new resume action is sent over. */
3433 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3437 resume_clear_callback (lp
, NULL
);
3440 if (linux_target
->low_status_is_event (status
))
3442 if (debug_linux_nat
)
3443 fprintf_unfiltered (gdb_stdlog
,
3444 "LLW: trap ptid is %s.\n",
3445 target_pid_to_str (lp
->ptid
));
3448 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3450 *ourstatus
= lp
->waitstatus
;
3451 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3454 store_waitstatus (ourstatus
, status
);
3456 if (debug_linux_nat
)
3457 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3459 restore_child_signals_mask (&prev_mask
);
3461 if (last_resume_kind
== resume_stop
3462 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3463 && WSTOPSIG (status
) == SIGSTOP
)
3465 /* A thread that has been requested to stop by GDB with
3466 target_stop, and it stopped cleanly, so report as SIG0. The
3467 use of SIGSTOP is an implementation detail. */
3468 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3471 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3472 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3475 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3477 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
)
3478 return filter_exit_event (lp
, ourstatus
);
3483 /* Resume LWPs that are currently stopped without any pending status
3484 to report, but are resumed from the core's perspective. */
3487 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3489 ptid_t
*wait_ptid_p
= (ptid_t
*) data
;
3493 if (debug_linux_nat
)
3494 fprintf_unfiltered (gdb_stdlog
,
3495 "RSRL: NOT resuming LWP %s, not stopped\n",
3496 target_pid_to_str (lp
->ptid
));
3498 else if (!lp
->resumed
)
3500 if (debug_linux_nat
)
3501 fprintf_unfiltered (gdb_stdlog
,
3502 "RSRL: NOT resuming LWP %s, not resumed\n",
3503 target_pid_to_str (lp
->ptid
));
3505 else if (lwp_status_pending_p (lp
))
3507 if (debug_linux_nat
)
3508 fprintf_unfiltered (gdb_stdlog
,
3509 "RSRL: NOT resuming LWP %s, has pending status\n",
3510 target_pid_to_str (lp
->ptid
));
3514 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3515 struct gdbarch
*gdbarch
= regcache
->arch ();
3519 CORE_ADDR pc
= regcache_read_pc (regcache
);
3520 int leave_stopped
= 0;
3522 /* Don't bother if there's a breakpoint at PC that we'd hit
3523 immediately, and we're not waiting for this LWP. */
3524 if (!lp
->ptid
.matches (*wait_ptid_p
))
3526 if (breakpoint_inserted_here_p (regcache
->aspace (), pc
))
3532 if (debug_linux_nat
)
3533 fprintf_unfiltered (gdb_stdlog
,
3534 "RSRL: resuming stopped-resumed LWP %s at "
3536 target_pid_to_str (lp
->ptid
),
3537 paddress (gdbarch
, pc
),
3540 linux_resume_one_lwp_throw (lp
, lp
->step
, GDB_SIGNAL_0
);
3543 CATCH (ex
, RETURN_MASK_ERROR
)
3545 if (!check_ptrace_stopped_lwp_gone (lp
))
3546 throw_exception (ex
);
3555 linux_nat_target::wait (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3560 if (debug_linux_nat
)
3562 std::string options_string
= target_options_to_string (target_options
);
3563 fprintf_unfiltered (gdb_stdlog
,
3564 "linux_nat_wait: [%s], [%s]\n",
3565 target_pid_to_str (ptid
),
3566 options_string
.c_str ());
3569 /* Flush the async file first. */
3570 if (target_is_async_p ())
3571 async_file_flush ();
3573 /* Resume LWPs that are currently stopped without any pending status
3574 to report, but are resumed from the core's perspective. LWPs get
3575 in this state if we find them stopping at a time we're not
3576 interested in reporting the event (target_wait on a
3577 specific_process, for example, see linux_nat_wait_1), and
3578 meanwhile the event became uninteresting. Don't bother resuming
3579 LWPs we're not going to wait for if they'd stop immediately. */
3580 if (target_is_non_stop_p ())
3581 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3583 event_ptid
= linux_nat_wait_1 (ptid
, ourstatus
, target_options
);
3585 /* If we requested any event, and something came out, assume there
3586 may be more. If we requested a specific lwp or process, also
3587 assume there may be more. */
3588 if (target_is_async_p ()
3589 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3590 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3591 || ptid
!= minus_one_ptid
))
3600 kill_one_lwp (pid_t pid
)
3602 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3605 kill_lwp (pid
, SIGKILL
);
3606 if (debug_linux_nat
)
3608 int save_errno
= errno
;
3610 fprintf_unfiltered (gdb_stdlog
,
3611 "KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid
,
3612 save_errno
? safe_strerror (save_errno
) : "OK");
3615 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3618 ptrace (PTRACE_KILL
, pid
, 0, 0);
3619 if (debug_linux_nat
)
3621 int save_errno
= errno
;
3623 fprintf_unfiltered (gdb_stdlog
,
3624 "KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid
,
3625 save_errno
? safe_strerror (save_errno
) : "OK");
3629 /* Wait for an LWP to die. */
3632 kill_wait_one_lwp (pid_t pid
)
3636 /* We must make sure that there are no pending events (delayed
3637 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3638 program doesn't interfere with any following debugging session. */
3642 res
= my_waitpid (pid
, NULL
, __WALL
);
3643 if (res
!= (pid_t
) -1)
3645 if (debug_linux_nat
)
3646 fprintf_unfiltered (gdb_stdlog
,
3647 "KWC: wait %ld received unknown.\n",
3649 /* The Linux kernel sometimes fails to kill a thread
3650 completely after PTRACE_KILL; that goes from the stop
3651 point in do_fork out to the one in get_signal_to_deliver
3652 and waits again. So kill it again. */
3658 gdb_assert (res
== -1 && errno
== ECHILD
);
3661 /* Callback for iterate_over_lwps. */
3664 kill_callback (struct lwp_info
*lp
, void *data
)
3666 kill_one_lwp (lp
->ptid
.lwp ());
3670 /* Callback for iterate_over_lwps. */
3673 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3675 kill_wait_one_lwp (lp
->ptid
.lwp ());
3679 /* Kill the fork children of any threads of inferior INF that are
3680 stopped at a fork event. */
3683 kill_unfollowed_fork_children (struct inferior
*inf
)
3685 for (thread_info
*thread
: inf
->non_exited_threads ())
3687 struct target_waitstatus
*ws
= &thread
->pending_follow
;
3689 if (ws
->kind
== TARGET_WAITKIND_FORKED
3690 || ws
->kind
== TARGET_WAITKIND_VFORKED
)
3692 ptid_t child_ptid
= ws
->value
.related_pid
;
3693 int child_pid
= child_ptid
.pid ();
3694 int child_lwp
= child_ptid
.lwp ();
3696 kill_one_lwp (child_lwp
);
3697 kill_wait_one_lwp (child_lwp
);
3699 /* Let the arch-specific native code know this process is
3701 linux_target
->low_forget_process (child_pid
);
3707 linux_nat_target::kill ()
3709 /* If we're stopped while forking and we haven't followed yet,
3710 kill the other task. We need to do this first because the
3711 parent will be sleeping if this is a vfork. */
3712 kill_unfollowed_fork_children (current_inferior ());
3714 if (forks_exist_p ())
3715 linux_fork_killall ();
3718 ptid_t ptid
= ptid_t (inferior_ptid
.pid ());
3720 /* Stop all threads before killing them, since ptrace requires
3721 that the thread is stopped to sucessfully PTRACE_KILL. */
3722 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3723 /* ... and wait until all of them have reported back that
3724 they're no longer running. */
3725 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3727 /* Kill all LWP's ... */
3728 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3730 /* ... and wait until we've flushed all events. */
3731 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3734 target_mourn_inferior (inferior_ptid
);
3738 linux_nat_target::mourn_inferior ()
3740 int pid
= inferior_ptid
.pid ();
3742 purge_lwp_list (pid
);
3744 if (! forks_exist_p ())
3745 /* Normal case, no other forks available. */
3746 inf_ptrace_target::mourn_inferior ();
3748 /* Multi-fork case. The current inferior_ptid has exited, but
3749 there are other viable forks to debug. Delete the exiting
3750 one and context-switch to the first available. */
3751 linux_fork_mourn_inferior ();
3753 /* Let the arch-specific native code know this process is gone. */
3754 linux_target
->low_forget_process (pid
);
3757 /* Convert a native/host siginfo object, into/from the siginfo in the
3758 layout of the inferiors' architecture. */
3761 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3763 /* If the low target didn't do anything, then just do a straight
3765 if (!linux_target
->low_siginfo_fixup (siginfo
, inf_siginfo
, direction
))
3768 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3770 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3774 static enum target_xfer_status
3775 linux_xfer_siginfo (enum target_object object
,
3776 const char *annex
, gdb_byte
*readbuf
,
3777 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3778 ULONGEST
*xfered_len
)
3782 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3784 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3785 gdb_assert (readbuf
|| writebuf
);
3787 pid
= inferior_ptid
.lwp ();
3789 pid
= inferior_ptid
.pid ();
3791 if (offset
> sizeof (siginfo
))
3792 return TARGET_XFER_E_IO
;
3795 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3797 return TARGET_XFER_E_IO
;
3799 /* When GDB is built as a 64-bit application, ptrace writes into
3800 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3801 inferior with a 64-bit GDB should look the same as debugging it
3802 with a 32-bit GDB, we need to convert it. GDB core always sees
3803 the converted layout, so any read/write will have to be done
3805 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3807 if (offset
+ len
> sizeof (siginfo
))
3808 len
= sizeof (siginfo
) - offset
;
3810 if (readbuf
!= NULL
)
3811 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3814 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3816 /* Convert back to ptrace layout before flushing it out. */
3817 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3820 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3822 return TARGET_XFER_E_IO
;
3826 return TARGET_XFER_OK
;
3829 static enum target_xfer_status
3830 linux_nat_xfer_osdata (enum target_object object
,
3831 const char *annex
, gdb_byte
*readbuf
,
3832 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3833 ULONGEST
*xfered_len
);
3835 static enum target_xfer_status
3836 linux_proc_xfer_spu (enum target_object object
,
3837 const char *annex
, gdb_byte
*readbuf
,
3838 const gdb_byte
*writebuf
,
3839 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
);
3841 static enum target_xfer_status
3842 linux_proc_xfer_partial (enum target_object object
,
3843 const char *annex
, gdb_byte
*readbuf
,
3844 const gdb_byte
*writebuf
,
3845 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
);
3847 enum target_xfer_status
3848 linux_nat_target::xfer_partial (enum target_object object
,
3849 const char *annex
, gdb_byte
*readbuf
,
3850 const gdb_byte
*writebuf
,
3851 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3853 enum target_xfer_status xfer
;
3855 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3856 return linux_xfer_siginfo (object
, annex
, readbuf
, writebuf
,
3857 offset
, len
, xfered_len
);
3859 /* The target is connected but no live inferior is selected. Pass
3860 this request down to a lower stratum (e.g., the executable
3862 if (object
== TARGET_OBJECT_MEMORY
&& inferior_ptid
== null_ptid
)
3863 return TARGET_XFER_EOF
;
3865 if (object
== TARGET_OBJECT_AUXV
)
3866 return memory_xfer_auxv (this, object
, annex
, readbuf
, writebuf
,
3867 offset
, len
, xfered_len
);
3869 if (object
== TARGET_OBJECT_OSDATA
)
3870 return linux_nat_xfer_osdata (object
, annex
, readbuf
, writebuf
,
3871 offset
, len
, xfered_len
);
3873 if (object
== TARGET_OBJECT_SPU
)
3874 return linux_proc_xfer_spu (object
, annex
, readbuf
, writebuf
,
3875 offset
, len
, xfered_len
);
3877 /* GDB calculates all addresses in the largest possible address
3879 The address width must be masked before its final use - either by
3880 linux_proc_xfer_partial or inf_ptrace_target::xfer_partial.
3882 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
3884 if (object
== TARGET_OBJECT_MEMORY
)
3886 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
3888 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
3889 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
3892 xfer
= linux_proc_xfer_partial (object
, annex
, readbuf
, writebuf
,
3893 offset
, len
, xfered_len
);
3894 if (xfer
!= TARGET_XFER_EOF
)
3897 return inf_ptrace_target::xfer_partial (object
, annex
, readbuf
, writebuf
,
3898 offset
, len
, xfered_len
);
3902 linux_nat_target::thread_alive (ptid_t ptid
)
3904 /* As long as a PTID is in lwp list, consider it alive. */
3905 return find_lwp_pid (ptid
) != NULL
;
3908 /* Implement the to_update_thread_list target method for this
3912 linux_nat_target::update_thread_list ()
3914 struct lwp_info
*lwp
;
3916 /* We add/delete threads from the list as clone/exit events are
3917 processed, so just try deleting exited threads still in the
3919 delete_exited_threads ();
3921 /* Update the processor core that each lwp/thread was last seen
3925 /* Avoid accessing /proc if the thread hasn't run since we last
3926 time we fetched the thread's core. Accessing /proc becomes
3927 noticeably expensive when we have thousands of LWPs. */
3928 if (lwp
->core
== -1)
3929 lwp
->core
= linux_common_core_of_thread (lwp
->ptid
);
3934 linux_nat_target::pid_to_str (ptid_t ptid
)
3936 static char buf
[64];
3939 && (ptid
.pid () != ptid
.lwp ()
3940 || num_lwps (ptid
.pid ()) > 1))
3942 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid
.lwp ());
3946 return normal_pid_to_str (ptid
);
3950 linux_nat_target::thread_name (struct thread_info
*thr
)
3952 return linux_proc_tid_get_name (thr
->ptid
);
3955 /* Accepts an integer PID; Returns a string representing a file that
3956 can be opened to get the symbols for the child process. */
3959 linux_nat_target::pid_to_exec_file (int pid
)
3961 return linux_proc_pid_to_exec_file (pid
);
3964 /* Implement the to_xfer_partial target method using /proc/<pid>/mem.
3965 Because we can use a single read/write call, this can be much more
3966 efficient than banging away at PTRACE_PEEKTEXT. */
3968 static enum target_xfer_status
3969 linux_proc_xfer_partial (enum target_object object
,
3970 const char *annex
, gdb_byte
*readbuf
,
3971 const gdb_byte
*writebuf
,
3972 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3978 if (object
!= TARGET_OBJECT_MEMORY
)
3979 return TARGET_XFER_EOF
;
3981 /* Don't bother for one word. */
3982 if (len
< 3 * sizeof (long))
3983 return TARGET_XFER_EOF
;
3985 /* We could keep this file open and cache it - possibly one per
3986 thread. That requires some juggling, but is even faster. */
3987 xsnprintf (filename
, sizeof filename
, "/proc/%ld/mem",
3988 inferior_ptid
.lwp ());
3989 fd
= gdb_open_cloexec (filename
, ((readbuf
? O_RDONLY
: O_WRONLY
)
3992 return TARGET_XFER_EOF
;
3994 /* Use pread64/pwrite64 if available, since they save a syscall and can
3995 handle 64-bit offsets even on 32-bit platforms (for instance, SPARC
3996 debugging a SPARC64 application). */
3998 ret
= (readbuf
? pread64 (fd
, readbuf
, len
, offset
)
3999 : pwrite64 (fd
, writebuf
, len
, offset
));
4001 ret
= lseek (fd
, offset
, SEEK_SET
);
4003 ret
= (readbuf
? read (fd
, readbuf
, len
)
4004 : write (fd
, writebuf
, len
));
4009 if (ret
== -1 || ret
== 0)
4010 return TARGET_XFER_EOF
;
4014 return TARGET_XFER_OK
;
4019 /* Enumerate spufs IDs for process PID. */
4021 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
4023 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
4025 LONGEST written
= 0;
4028 struct dirent
*entry
;
4030 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
4031 dir
= opendir (path
);
4036 while ((entry
= readdir (dir
)) != NULL
)
4042 fd
= atoi (entry
->d_name
);
4046 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
4047 if (stat (path
, &st
) != 0)
4049 if (!S_ISDIR (st
.st_mode
))
4052 if (statfs (path
, &stfs
) != 0)
4054 if (stfs
.f_type
!= SPUFS_MAGIC
)
4057 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
4059 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
4069 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4070 object type, using the /proc file system. */
4072 static enum target_xfer_status
4073 linux_proc_xfer_spu (enum target_object object
,
4074 const char *annex
, gdb_byte
*readbuf
,
4075 const gdb_byte
*writebuf
,
4076 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
4081 int pid
= inferior_ptid
.lwp ();
4086 return TARGET_XFER_E_IO
;
4089 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4092 return TARGET_XFER_E_IO
;
4094 return TARGET_XFER_EOF
;
4097 *xfered_len
= (ULONGEST
) l
;
4098 return TARGET_XFER_OK
;
4103 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4104 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4106 return TARGET_XFER_E_IO
;
4109 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4112 return TARGET_XFER_EOF
;
4116 ret
= write (fd
, writebuf
, (size_t) len
);
4118 ret
= read (fd
, readbuf
, (size_t) len
);
4123 return TARGET_XFER_E_IO
;
4125 return TARGET_XFER_EOF
;
4128 *xfered_len
= (ULONGEST
) ret
;
4129 return TARGET_XFER_OK
;
4134 /* Parse LINE as a signal set and add its set bits to SIGS. */
4137 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4139 int len
= strlen (line
) - 1;
4143 if (line
[len
] != '\n')
4144 error (_("Could not parse signal set: %s"), line
);
4152 if (*p
>= '0' && *p
<= '9')
4154 else if (*p
>= 'a' && *p
<= 'f')
4155 digit
= *p
- 'a' + 10;
4157 error (_("Could not parse signal set: %s"), line
);
4162 sigaddset (sigs
, signum
+ 1);
4164 sigaddset (sigs
, signum
+ 2);
4166 sigaddset (sigs
, signum
+ 3);
4168 sigaddset (sigs
, signum
+ 4);
4174 /* Find process PID's pending signals from /proc/pid/status and set
4178 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4179 sigset_t
*blocked
, sigset_t
*ignored
)
4181 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4183 sigemptyset (pending
);
4184 sigemptyset (blocked
);
4185 sigemptyset (ignored
);
4186 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4187 gdb_file_up procfile
= gdb_fopen_cloexec (fname
, "r");
4188 if (procfile
== NULL
)
4189 error (_("Could not open %s"), fname
);
4191 while (fgets (buffer
, PATH_MAX
, procfile
.get ()) != NULL
)
4193 /* Normal queued signals are on the SigPnd line in the status
4194 file. However, 2.6 kernels also have a "shared" pending
4195 queue for delivering signals to a thread group, so check for
4198 Unfortunately some Red Hat kernels include the shared pending
4199 queue but not the ShdPnd status field. */
4201 if (startswith (buffer
, "SigPnd:\t"))
4202 add_line_to_sigset (buffer
+ 8, pending
);
4203 else if (startswith (buffer
, "ShdPnd:\t"))
4204 add_line_to_sigset (buffer
+ 8, pending
);
4205 else if (startswith (buffer
, "SigBlk:\t"))
4206 add_line_to_sigset (buffer
+ 8, blocked
);
4207 else if (startswith (buffer
, "SigIgn:\t"))
4208 add_line_to_sigset (buffer
+ 8, ignored
);
4212 static enum target_xfer_status
4213 linux_nat_xfer_osdata (enum target_object object
,
4214 const char *annex
, gdb_byte
*readbuf
,
4215 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4216 ULONGEST
*xfered_len
)
4218 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4220 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4221 if (*xfered_len
== 0)
4222 return TARGET_XFER_EOF
;
4224 return TARGET_XFER_OK
;
4227 std::vector
<static_tracepoint_marker
>
4228 linux_nat_target::static_tracepoint_markers_by_strid (const char *strid
)
4230 char s
[IPA_CMD_BUF_SIZE
];
4231 int pid
= inferior_ptid
.pid ();
4232 std::vector
<static_tracepoint_marker
> markers
;
4234 ptid_t ptid
= ptid_t (pid
, 0, 0);
4235 static_tracepoint_marker marker
;
4240 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4241 s
[sizeof ("qTfSTM")] = 0;
4243 agent_run_command (pid
, s
, strlen (s
) + 1);
4246 SCOPE_EXIT
{ target_continue_no_signal (ptid
); };
4252 parse_static_tracepoint_marker_definition (p
, &p
, &marker
);
4254 if (strid
== NULL
|| marker
.str_id
== strid
)
4255 markers
.push_back (std::move (marker
));
4257 while (*p
++ == ','); /* comma-separated list */
4259 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4260 s
[sizeof ("qTsSTM")] = 0;
4261 agent_run_command (pid
, s
, strlen (s
) + 1);
4268 /* target_is_async_p implementation. */
4271 linux_nat_target::is_async_p ()
4273 return linux_is_async_p ();
4276 /* target_can_async_p implementation. */
4279 linux_nat_target::can_async_p ()
4281 /* We're always async, unless the user explicitly prevented it with the
4282 "maint set target-async" command. */
4283 return target_async_permitted
;
4287 linux_nat_target::supports_non_stop ()
4292 /* to_always_non_stop_p implementation. */
4295 linux_nat_target::always_non_stop_p ()
4300 /* True if we want to support multi-process. To be removed when GDB
4301 supports multi-exec. */
4303 int linux_multi_process
= 1;
4306 linux_nat_target::supports_multi_process ()
4308 return linux_multi_process
;
4312 linux_nat_target::supports_disable_randomization ()
4314 #ifdef HAVE_PERSONALITY
4321 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4322 so we notice when any child changes state, and notify the
4323 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4324 above to wait for the arrival of a SIGCHLD. */
4327 sigchld_handler (int signo
)
4329 int old_errno
= errno
;
4331 if (debug_linux_nat
)
4332 ui_file_write_async_safe (gdb_stdlog
,
4333 "sigchld\n", sizeof ("sigchld\n") - 1);
4335 if (signo
== SIGCHLD
4336 && linux_nat_event_pipe
[0] != -1)
4337 async_file_mark (); /* Let the event loop know that there are
4338 events to handle. */
4343 /* Callback registered with the target events file descriptor. */
4346 handle_target_event (int error
, gdb_client_data client_data
)
4348 inferior_event_handler (INF_REG_EVENT
, NULL
);
4351 /* Create/destroy the target events pipe. Returns previous state. */
4354 linux_async_pipe (int enable
)
4356 int previous
= linux_is_async_p ();
4358 if (previous
!= enable
)
4362 /* Block child signals while we create/destroy the pipe, as
4363 their handler writes to it. */
4364 block_child_signals (&prev_mask
);
4368 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4369 internal_error (__FILE__
, __LINE__
,
4370 "creating event pipe failed.");
4372 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4373 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4377 close (linux_nat_event_pipe
[0]);
4378 close (linux_nat_event_pipe
[1]);
4379 linux_nat_event_pipe
[0] = -1;
4380 linux_nat_event_pipe
[1] = -1;
4383 restore_child_signals_mask (&prev_mask
);
4389 /* target_async implementation. */
4392 linux_nat_target::async (int enable
)
4396 if (!linux_async_pipe (1))
4398 add_file_handler (linux_nat_event_pipe
[0],
4399 handle_target_event
, NULL
);
4400 /* There may be pending events to handle. Tell the event loop
4407 delete_file_handler (linux_nat_event_pipe
[0]);
4408 linux_async_pipe (0);
4413 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4417 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4421 if (debug_linux_nat
)
4422 fprintf_unfiltered (gdb_stdlog
,
4423 "LNSL: running -> suspending %s\n",
4424 target_pid_to_str (lwp
->ptid
));
4427 if (lwp
->last_resume_kind
== resume_stop
)
4429 if (debug_linux_nat
)
4430 fprintf_unfiltered (gdb_stdlog
,
4431 "linux-nat: already stopping LWP %ld at "
4437 stop_callback (lwp
, NULL
);
4438 lwp
->last_resume_kind
= resume_stop
;
4442 /* Already known to be stopped; do nothing. */
4444 if (debug_linux_nat
)
4446 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4447 fprintf_unfiltered (gdb_stdlog
,
4448 "LNSL: already stopped/stop_requested %s\n",
4449 target_pid_to_str (lwp
->ptid
));
4451 fprintf_unfiltered (gdb_stdlog
,
4452 "LNSL: already stopped/no "
4453 "stop_requested yet %s\n",
4454 target_pid_to_str (lwp
->ptid
));
4461 linux_nat_target::stop (ptid_t ptid
)
4463 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4467 linux_nat_target::close ()
4469 /* Unregister from the event loop. */
4473 inf_ptrace_target::close ();
4476 /* When requests are passed down from the linux-nat layer to the
4477 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4478 used. The address space pointer is stored in the inferior object,
4479 but the common code that is passed such ptid can't tell whether
4480 lwpid is a "main" process id or not (it assumes so). We reverse
4481 look up the "main" process id from the lwp here. */
4483 struct address_space
*
4484 linux_nat_target::thread_address_space (ptid_t ptid
)
4486 struct lwp_info
*lwp
;
4487 struct inferior
*inf
;
4490 if (ptid
.lwp () == 0)
4492 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4494 lwp
= find_lwp_pid (ptid
);
4495 pid
= lwp
->ptid
.pid ();
4499 /* A (pid,lwpid,0) ptid. */
4503 inf
= find_inferior_pid (pid
);
4504 gdb_assert (inf
!= NULL
);
4508 /* Return the cached value of the processor core for thread PTID. */
4511 linux_nat_target::core_of_thread (ptid_t ptid
)
4513 struct lwp_info
*info
= find_lwp_pid (ptid
);
4520 /* Implementation of to_filesystem_is_local. */
4523 linux_nat_target::filesystem_is_local ()
4525 struct inferior
*inf
= current_inferior ();
4527 if (inf
->fake_pid_p
|| inf
->pid
== 0)
4530 return linux_ns_same (inf
->pid
, LINUX_NS_MNT
);
4533 /* Convert the INF argument passed to a to_fileio_* method
4534 to a process ID suitable for passing to its corresponding
4535 linux_mntns_* function. If INF is non-NULL then the
4536 caller is requesting the filesystem seen by INF. If INF
4537 is NULL then the caller is requesting the filesystem seen
4538 by the GDB. We fall back to GDB's filesystem in the case
4539 that INF is non-NULL but its PID is unknown. */
4542 linux_nat_fileio_pid_of (struct inferior
*inf
)
4544 if (inf
== NULL
|| inf
->fake_pid_p
|| inf
->pid
== 0)
4550 /* Implementation of to_fileio_open. */
4553 linux_nat_target::fileio_open (struct inferior
*inf
, const char *filename
,
4554 int flags
, int mode
, int warn_if_slow
,
4561 if (fileio_to_host_openflags (flags
, &nat_flags
) == -1
4562 || fileio_to_host_mode (mode
, &nat_mode
) == -1)
4564 *target_errno
= FILEIO_EINVAL
;
4568 fd
= linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf
),
4569 filename
, nat_flags
, nat_mode
);
4571 *target_errno
= host_to_fileio_error (errno
);
4576 /* Implementation of to_fileio_readlink. */
4578 gdb::optional
<std::string
>
4579 linux_nat_target::fileio_readlink (struct inferior
*inf
, const char *filename
,
4585 len
= linux_mntns_readlink (linux_nat_fileio_pid_of (inf
),
4586 filename
, buf
, sizeof (buf
));
4589 *target_errno
= host_to_fileio_error (errno
);
4593 return std::string (buf
, len
);
4596 /* Implementation of to_fileio_unlink. */
4599 linux_nat_target::fileio_unlink (struct inferior
*inf
, const char *filename
,
4604 ret
= linux_mntns_unlink (linux_nat_fileio_pid_of (inf
),
4607 *target_errno
= host_to_fileio_error (errno
);
4612 /* Implementation of the to_thread_events method. */
4615 linux_nat_target::thread_events (int enable
)
4617 report_thread_events
= enable
;
4620 linux_nat_target::linux_nat_target ()
4622 /* We don't change the stratum; this target will sit at
4623 process_stratum and thread_db will set at thread_stratum. This
4624 is a little strange, since this is a multi-threaded-capable
4625 target, but we want to be on the stack below thread_db, and we
4626 also want to be used for single-threaded processes. */
4629 /* See linux-nat.h. */
4632 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4641 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4644 memset (siginfo
, 0, sizeof (*siginfo
));
4650 /* See nat/linux-nat.h. */
4653 current_lwp_ptid (void)
4655 gdb_assert (inferior_ptid
.lwp_p ());
4656 return inferior_ptid
;
4660 _initialize_linux_nat (void)
4662 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4663 &debug_linux_nat
, _("\
4664 Set debugging of GNU/Linux lwp module."), _("\
4665 Show debugging of GNU/Linux lwp module."), _("\
4666 Enables printf debugging output."),
4668 show_debug_linux_nat
,
4669 &setdebuglist
, &showdebuglist
);
4671 add_setshow_boolean_cmd ("linux-namespaces", class_maintenance
,
4672 &debug_linux_namespaces
, _("\
4673 Set debugging of GNU/Linux namespaces module."), _("\
4674 Show debugging of GNU/Linux namespaces module."), _("\
4675 Enables printf debugging output."),
4678 &setdebuglist
, &showdebuglist
);
4680 /* Save this mask as the default. */
4681 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
4683 /* Install a SIGCHLD handler. */
4684 sigchld_action
.sa_handler
= sigchld_handler
;
4685 sigemptyset (&sigchld_action
.sa_mask
);
4686 sigchld_action
.sa_flags
= SA_RESTART
;
4688 /* Make it the default. */
4689 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4691 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4692 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4693 sigdelset (&suspend_mask
, SIGCHLD
);
4695 sigemptyset (&blocked_mask
);
4697 lwp_lwpid_htab_create ();
4701 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4702 the GNU/Linux Threads library and therefore doesn't really belong
4705 /* Return the set of signals used by the threads library in *SET. */
4708 lin_thread_get_thread_signals (sigset_t
*set
)
4712 /* NPTL reserves the first two RT signals, but does not provide any
4713 way for the debugger to query the signal numbers - fortunately
4714 they don't change. */
4715 sigaddset (set
, __SIGRTMIN
);
4716 sigaddset (set
, __SIGRTMIN
+ 1);