1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2015 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
27 #ifdef HAVE_TKILL_SYSCALL
29 #include <sys/syscall.h>
31 #include <sys/ptrace.h>
32 #include "linux-nat.h"
33 #include "nat/linux-ptrace.h"
34 #include "nat/linux-procfs.h"
35 #include "nat/linux-personality.h"
36 #include "linux-fork.h"
37 #include "gdbthread.h"
41 #include "inf-child.h"
42 #include "inf-ptrace.h"
44 #include <sys/procfs.h> /* for elf_gregset etc. */
45 #include "elf-bfd.h" /* for elfcore_write_* */
46 #include "gregset.h" /* for gregset */
47 #include "gdbcore.h" /* for get_exec_file */
48 #include <ctype.h> /* for isdigit */
49 #include <sys/stat.h> /* for struct stat */
50 #include <fcntl.h> /* for O_RDONLY */
52 #include "event-loop.h"
53 #include "event-top.h"
55 #include <sys/types.h>
57 #include "xml-support.h"
60 #include "nat/linux-osdata.h"
61 #include "linux-tdep.h"
64 #include "tracepoint.h"
66 #include "target-descriptions.h"
67 #include "filestuff.h"
71 #define SPUFS_MAGIC 0x23c9b64e
74 /* This comment documents high-level logic of this file.
76 Waiting for events in sync mode
77 ===============================
79 When waiting for an event in a specific thread, we just use waitpid, passing
80 the specific pid, and not passing WNOHANG.
82 When waiting for an event in all threads, waitpid is not quite good. Prior to
83 version 2.4, Linux can either wait for event in main thread, or in secondary
84 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
85 miss an event. The solution is to use non-blocking waitpid, together with
86 sigsuspend. First, we use non-blocking waitpid to get an event in the main
87 process, if any. Second, we use non-blocking waitpid with the __WCLONED
88 flag to check for events in cloned processes. If nothing is found, we use
89 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
90 happened to a child process -- and SIGCHLD will be delivered both for events
91 in main debugged process and in cloned processes. As soon as we know there's
92 an event, we get back to calling nonblocking waitpid with and without
95 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
96 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
97 blocked, the signal becomes pending and sigsuspend immediately
98 notices it and returns.
100 Waiting for events in async mode
101 ================================
103 In async mode, GDB should always be ready to handle both user input
104 and target events, so neither blocking waitpid nor sigsuspend are
105 viable options. Instead, we should asynchronously notify the GDB main
106 event loop whenever there's an unprocessed event from the target. We
107 detect asynchronous target events by handling SIGCHLD signals. To
108 notify the event loop about target events, the self-pipe trick is used
109 --- a pipe is registered as waitable event source in the event loop,
110 the event loop select/poll's on the read end of this pipe (as well on
111 other event sources, e.g., stdin), and the SIGCHLD handler writes a
112 byte to this pipe. This is more portable than relying on
113 pselect/ppoll, since on kernels that lack those syscalls, libc
114 emulates them with select/poll+sigprocmask, and that is racy
115 (a.k.a. plain broken).
117 Obviously, if we fail to notify the event loop if there's a target
118 event, it's bad. OTOH, if we notify the event loop when there's no
119 event from the target, linux_nat_wait will detect that there's no real
120 event to report, and return event of type TARGET_WAITKIND_IGNORE.
121 This is mostly harmless, but it will waste time and is better avoided.
123 The main design point is that every time GDB is outside linux-nat.c,
124 we have a SIGCHLD handler installed that is called when something
125 happens to the target and notifies the GDB event loop. Whenever GDB
126 core decides to handle the event, and calls into linux-nat.c, we
127 process things as in sync mode, except that the we never block in
130 While processing an event, we may end up momentarily blocked in
131 waitpid calls. Those waitpid calls, while blocking, are guarantied to
132 return quickly. E.g., in all-stop mode, before reporting to the core
133 that an LWP hit a breakpoint, all LWPs are stopped by sending them
134 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
135 Note that this is different from blocking indefinitely waiting for the
136 next event --- here, we're already handling an event.
141 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
142 signal is not entirely significant; we just need for a signal to be delivered,
143 so that we can intercept it. SIGSTOP's advantage is that it can not be
144 blocked. A disadvantage is that it is not a real-time signal, so it can only
145 be queued once; we do not keep track of other sources of SIGSTOP.
147 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
148 use them, because they have special behavior when the signal is generated -
149 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
150 kills the entire thread group.
152 A delivered SIGSTOP would stop the entire thread group, not just the thread we
153 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
154 cancel it (by PTRACE_CONT without passing SIGSTOP).
156 We could use a real-time signal instead. This would solve those problems; we
157 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
158 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
159 generates it, and there are races with trying to find a signal that is not
163 #define O_LARGEFILE 0
166 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
167 the use of the multi-threaded target. */
168 static struct target_ops
*linux_ops
;
169 static struct target_ops linux_ops_saved
;
171 /* The method to call, if any, when a new thread is attached. */
172 static void (*linux_nat_new_thread
) (struct lwp_info
*);
174 /* The method to call, if any, when a new fork is attached. */
175 static linux_nat_new_fork_ftype
*linux_nat_new_fork
;
177 /* The method to call, if any, when a process is no longer
179 static linux_nat_forget_process_ftype
*linux_nat_forget_process_hook
;
181 /* Hook to call prior to resuming a thread. */
182 static void (*linux_nat_prepare_to_resume
) (struct lwp_info
*);
184 /* The method to call, if any, when the siginfo object needs to be
185 converted between the layout returned by ptrace, and the layout in
186 the architecture of the inferior. */
187 static int (*linux_nat_siginfo_fixup
) (siginfo_t
*,
191 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
192 Called by our to_xfer_partial. */
193 static target_xfer_partial_ftype
*super_xfer_partial
;
195 /* The saved to_close method, inherited from inf-ptrace.c.
196 Called by our to_close. */
197 static void (*super_close
) (struct target_ops
*);
199 static unsigned int debug_linux_nat
;
201 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
202 struct cmd_list_element
*c
, const char *value
)
204 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
208 struct simple_pid_list
212 struct simple_pid_list
*next
;
214 struct simple_pid_list
*stopped_pids
;
216 /* Async mode support. */
218 /* The read/write ends of the pipe registered as waitable file in the
220 static int linux_nat_event_pipe
[2] = { -1, -1 };
222 /* True if we're currently in async mode. */
223 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
225 /* Flush the event pipe. */
228 async_file_flush (void)
235 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
237 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
240 /* Put something (anything, doesn't matter what, or how much) in event
241 pipe, so that the select/poll in the event-loop realizes we have
242 something to process. */
245 async_file_mark (void)
249 /* It doesn't really matter what the pipe contains, as long we end
250 up with something in it. Might as well flush the previous
256 ret
= write (linux_nat_event_pipe
[1], "+", 1);
258 while (ret
== -1 && errno
== EINTR
);
260 /* Ignore EAGAIN. If the pipe is full, the event loop will already
261 be awakened anyway. */
264 static int kill_lwp (int lwpid
, int signo
);
266 static int stop_callback (struct lwp_info
*lp
, void *data
);
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 int check_stopped_by_breakpoint (struct lwp_info
*lp
);
280 static int sigtrap_is_event (int status
);
281 static int (*linux_nat_status_is_event
) (int status
) = sigtrap_is_event
;
284 /* Trivial list manipulation functions to keep track of a list of
285 new stopped processes. */
287 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
289 struct simple_pid_list
*new_pid
= xmalloc (sizeof (struct simple_pid_list
));
292 new_pid
->status
= status
;
293 new_pid
->next
= *listp
;
298 in_pid_list_p (struct simple_pid_list
*list
, int pid
)
300 struct simple_pid_list
*p
;
302 for (p
= list
; p
!= NULL
; p
= p
->next
)
309 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
311 struct simple_pid_list
**p
;
313 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
314 if ((*p
)->pid
== pid
)
316 struct simple_pid_list
*next
= (*p
)->next
;
318 *statusp
= (*p
)->status
;
326 /* Initialize ptrace warnings and check for supported ptrace
329 ATTACHED should be nonzero iff we attached to the inferior. */
332 linux_init_ptrace (pid_t pid
, int attached
)
334 linux_enable_event_reporting (pid
, attached
);
335 linux_ptrace_init_warnings ();
339 linux_child_post_attach (struct target_ops
*self
, int pid
)
341 linux_init_ptrace (pid
, 1);
345 linux_child_post_startup_inferior (struct target_ops
*self
, ptid_t ptid
)
347 linux_init_ptrace (ptid_get_pid (ptid
), 0);
350 /* Return the number of known LWPs in the tgid given by PID. */
358 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
359 if (ptid_get_pid (lp
->ptid
) == pid
)
365 /* Call delete_lwp with prototype compatible for make_cleanup. */
368 delete_lwp_cleanup (void *lp_voidp
)
370 struct lwp_info
*lp
= lp_voidp
;
372 delete_lwp (lp
->ptid
);
375 /* Target hook for follow_fork. On entry inferior_ptid must be the
376 ptid of the followed inferior. At return, inferior_ptid will be
380 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
,
385 struct lwp_info
*child_lp
= NULL
;
386 int status
= W_STOPCODE (0);
387 struct cleanup
*old_chain
;
389 int parent_pid
, child_pid
;
391 has_vforked
= (inferior_thread ()->pending_follow
.kind
392 == TARGET_WAITKIND_VFORKED
);
393 parent_pid
= ptid_get_lwp (inferior_ptid
);
395 parent_pid
= ptid_get_pid (inferior_ptid
);
397 = ptid_get_pid (inferior_thread ()->pending_follow
.value
.related_pid
);
400 /* We're already attached to the parent, by default. */
401 old_chain
= save_inferior_ptid ();
402 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
403 child_lp
= add_lwp (inferior_ptid
);
404 child_lp
->stopped
= 1;
405 child_lp
->last_resume_kind
= resume_stop
;
407 /* Detach new forked process? */
410 make_cleanup (delete_lwp_cleanup
, child_lp
);
412 if (linux_nat_prepare_to_resume
!= NULL
)
413 linux_nat_prepare_to_resume (child_lp
);
415 /* When debugging an inferior in an architecture that supports
416 hardware single stepping on a kernel without commit
417 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
418 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
419 set if the parent process had them set.
420 To work around this, single step the child process
421 once before detaching to clear the flags. */
423 if (!gdbarch_software_single_step_p (target_thread_architecture
426 linux_disable_event_reporting (child_pid
);
427 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
428 perror_with_name (_("Couldn't do single step"));
429 if (my_waitpid (child_pid
, &status
, 0) < 0)
430 perror_with_name (_("Couldn't wait vfork process"));
433 if (WIFSTOPPED (status
))
437 signo
= WSTOPSIG (status
);
439 && !signal_pass_state (gdb_signal_from_host (signo
)))
441 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
444 /* Resets value of inferior_ptid to parent ptid. */
445 do_cleanups (old_chain
);
449 /* Let the thread_db layer learn about this new process. */
450 check_for_thread_db ();
453 do_cleanups (old_chain
);
457 struct lwp_info
*parent_lp
;
459 parent_lp
= find_lwp_pid (pid_to_ptid (parent_pid
));
460 gdb_assert (linux_supports_tracefork () >= 0);
462 if (linux_supports_tracevforkdone ())
465 fprintf_unfiltered (gdb_stdlog
,
466 "LCFF: waiting for VFORK_DONE on %d\n",
468 parent_lp
->stopped
= 1;
470 /* We'll handle the VFORK_DONE event like any other
471 event, in target_wait. */
475 /* We can't insert breakpoints until the child has
476 finished with the shared memory region. We need to
477 wait until that happens. Ideal would be to just
479 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
480 - waitpid (parent_pid, &status, __WALL);
481 However, most architectures can't handle a syscall
482 being traced on the way out if it wasn't traced on
485 We might also think to loop, continuing the child
486 until it exits or gets a SIGTRAP. One problem is
487 that the child might call ptrace with PTRACE_TRACEME.
489 There's no simple and reliable way to figure out when
490 the vforked child will be done with its copy of the
491 shared memory. We could step it out of the syscall,
492 two instructions, let it go, and then single-step the
493 parent once. When we have hardware single-step, this
494 would work; with software single-step it could still
495 be made to work but we'd have to be able to insert
496 single-step breakpoints in the child, and we'd have
497 to insert -just- the single-step breakpoint in the
498 parent. Very awkward.
500 In the end, the best we can do is to make sure it
501 runs for a little while. Hopefully it will be out of
502 range of any breakpoints we reinsert. Usually this
503 is only the single-step breakpoint at vfork's return
507 fprintf_unfiltered (gdb_stdlog
,
508 "LCFF: no VFORK_DONE "
509 "support, sleeping a bit\n");
513 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
514 and leave it pending. The next linux_nat_resume call
515 will notice a pending event, and bypasses actually
516 resuming the inferior. */
517 parent_lp
->status
= 0;
518 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
519 parent_lp
->stopped
= 1;
521 /* If we're in async mode, need to tell the event loop
522 there's something here to process. */
523 if (target_is_async_p ())
530 struct lwp_info
*child_lp
;
532 child_lp
= add_lwp (inferior_ptid
);
533 child_lp
->stopped
= 1;
534 child_lp
->last_resume_kind
= resume_stop
;
536 /* Let the thread_db layer learn about this new process. */
537 check_for_thread_db ();
545 linux_child_insert_fork_catchpoint (struct target_ops
*self
, int pid
)
547 return !linux_supports_tracefork ();
551 linux_child_remove_fork_catchpoint (struct target_ops
*self
, int pid
)
557 linux_child_insert_vfork_catchpoint (struct target_ops
*self
, int pid
)
559 return !linux_supports_tracefork ();
563 linux_child_remove_vfork_catchpoint (struct target_ops
*self
, int pid
)
569 linux_child_insert_exec_catchpoint (struct target_ops
*self
, int pid
)
571 return !linux_supports_tracefork ();
575 linux_child_remove_exec_catchpoint (struct target_ops
*self
, int pid
)
581 linux_child_set_syscall_catchpoint (struct target_ops
*self
,
582 int pid
, int needed
, int any_count
,
583 int table_size
, int *table
)
585 if (!linux_supports_tracesysgood ())
588 /* On GNU/Linux, we ignore the arguments. It means that we only
589 enable the syscall catchpoints, but do not disable them.
591 Also, we do not use the `table' information because we do not
592 filter system calls here. We let GDB do the logic for us. */
596 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
597 are processes sharing the same VM space. A multi-threaded process
598 is basically a group of such processes. However, such a grouping
599 is almost entirely a user-space issue; the kernel doesn't enforce
600 such a grouping at all (this might change in the future). In
601 general, we'll rely on the threads library (i.e. the GNU/Linux
602 Threads library) to provide such a grouping.
604 It is perfectly well possible to write a multi-threaded application
605 without the assistance of a threads library, by using the clone
606 system call directly. This module should be able to give some
607 rudimentary support for debugging such applications if developers
608 specify the CLONE_PTRACE flag in the clone system call, and are
609 using the Linux kernel 2.4 or above.
611 Note that there are some peculiarities in GNU/Linux that affect
614 - In general one should specify the __WCLONE flag to waitpid in
615 order to make it report events for any of the cloned processes
616 (and leave it out for the initial process). However, if a cloned
617 process has exited the exit status is only reported if the
618 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
619 we cannot use it since GDB must work on older systems too.
621 - When a traced, cloned process exits and is waited for by the
622 debugger, the kernel reassigns it to the original parent and
623 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
624 library doesn't notice this, which leads to the "zombie problem":
625 When debugged a multi-threaded process that spawns a lot of
626 threads will run out of processes, even if the threads exit,
627 because the "zombies" stay around. */
629 /* List of known LWPs. */
630 struct lwp_info
*lwp_list
;
633 /* Original signal mask. */
634 static sigset_t normal_mask
;
636 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
637 _initialize_linux_nat. */
638 static sigset_t suspend_mask
;
640 /* Signals to block to make that sigsuspend work. */
641 static sigset_t blocked_mask
;
643 /* SIGCHLD action. */
644 struct sigaction sigchld_action
;
646 /* Block child signals (SIGCHLD and linux threads signals), and store
647 the previous mask in PREV_MASK. */
650 block_child_signals (sigset_t
*prev_mask
)
652 /* Make sure SIGCHLD is blocked. */
653 if (!sigismember (&blocked_mask
, SIGCHLD
))
654 sigaddset (&blocked_mask
, SIGCHLD
);
656 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
659 /* Restore child signals mask, previously returned by
660 block_child_signals. */
663 restore_child_signals_mask (sigset_t
*prev_mask
)
665 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
668 /* Mask of signals to pass directly to the inferior. */
669 static sigset_t pass_mask
;
671 /* Update signals to pass to the inferior. */
673 linux_nat_pass_signals (struct target_ops
*self
,
674 int numsigs
, unsigned char *pass_signals
)
678 sigemptyset (&pass_mask
);
680 for (signo
= 1; signo
< NSIG
; signo
++)
682 int target_signo
= gdb_signal_from_host (signo
);
683 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
684 sigaddset (&pass_mask
, signo
);
690 /* Prototypes for local functions. */
691 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
692 static int linux_thread_alive (ptid_t ptid
);
693 static char *linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
);
694 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
);
698 /* Destroy and free LP. */
701 lwp_free (struct lwp_info
*lp
)
703 xfree (lp
->arch_private
);
707 /* Remove all LWPs belong to PID from the lwp list. */
710 purge_lwp_list (int pid
)
712 struct lwp_info
*lp
, *lpprev
, *lpnext
;
716 for (lp
= lwp_list
; lp
; lp
= lpnext
)
720 if (ptid_get_pid (lp
->ptid
) == pid
)
725 lpprev
->next
= lp
->next
;
734 /* Add the LWP specified by PTID to the list. PTID is the first LWP
735 in the process. Return a pointer to the structure describing the
738 This differs from add_lwp in that we don't let the arch specific
739 bits know about this new thread. Current clients of this callback
740 take the opportunity to install watchpoints in the new thread, and
741 we shouldn't do that for the first thread. If we're spawning a
742 child ("run"), the thread executes the shell wrapper first, and we
743 shouldn't touch it until it execs the program we want to debug.
744 For "attach", it'd be okay to call the callback, but it's not
745 necessary, because watchpoints can't yet have been inserted into
748 static struct lwp_info
*
749 add_initial_lwp (ptid_t ptid
)
753 gdb_assert (ptid_lwp_p (ptid
));
755 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
757 memset (lp
, 0, sizeof (struct lwp_info
));
759 lp
->last_resume_kind
= resume_continue
;
760 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
771 /* Add the LWP specified by PID to the list. Return a pointer to the
772 structure describing the new LWP. The LWP should already be
775 static struct lwp_info
*
776 add_lwp (ptid_t ptid
)
780 lp
= add_initial_lwp (ptid
);
782 /* Let the arch specific bits know about this new thread. Current
783 clients of this callback take the opportunity to install
784 watchpoints in the new thread. We don't do this for the first
785 thread though. See add_initial_lwp. */
786 if (linux_nat_new_thread
!= NULL
)
787 linux_nat_new_thread (lp
);
792 /* Remove the LWP specified by PID from the list. */
795 delete_lwp (ptid_t ptid
)
797 struct lwp_info
*lp
, *lpprev
;
801 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
802 if (ptid_equal (lp
->ptid
, ptid
))
809 lpprev
->next
= lp
->next
;
816 /* Return a pointer to the structure describing the LWP corresponding
817 to PID. If no corresponding LWP could be found, return NULL. */
819 static struct lwp_info
*
820 find_lwp_pid (ptid_t ptid
)
825 if (ptid_lwp_p (ptid
))
826 lwp
= ptid_get_lwp (ptid
);
828 lwp
= ptid_get_pid (ptid
);
830 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
831 if (lwp
== ptid_get_lwp (lp
->ptid
))
837 /* Call CALLBACK with its second argument set to DATA for every LWP in
838 the list. If CALLBACK returns 1 for a particular LWP, return a
839 pointer to the structure describing that LWP immediately.
840 Otherwise return NULL. */
843 iterate_over_lwps (ptid_t filter
,
844 int (*callback
) (struct lwp_info
*, void *),
847 struct lwp_info
*lp
, *lpnext
;
849 for (lp
= lwp_list
; lp
; lp
= lpnext
)
853 if (ptid_match (lp
->ptid
, filter
))
855 if ((*callback
) (lp
, data
))
863 /* Update our internal state when changing from one checkpoint to
864 another indicated by NEW_PTID. We can only switch single-threaded
865 applications, so we only create one new LWP, and the previous list
869 linux_nat_switch_fork (ptid_t new_ptid
)
873 purge_lwp_list (ptid_get_pid (inferior_ptid
));
875 lp
= add_lwp (new_ptid
);
878 /* This changes the thread's ptid while preserving the gdb thread
879 num. Also changes the inferior pid, while preserving the
881 thread_change_ptid (inferior_ptid
, new_ptid
);
883 /* We've just told GDB core that the thread changed target id, but,
884 in fact, it really is a different thread, with different register
886 registers_changed ();
889 /* Handle the exit of a single thread LP. */
892 exit_lwp (struct lwp_info
*lp
)
894 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
898 if (print_thread_events
)
899 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
901 delete_thread (lp
->ptid
);
904 delete_lwp (lp
->ptid
);
907 /* Wait for the LWP specified by LP, which we have just attached to.
908 Returns a wait status for that LWP, to cache. */
911 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
914 pid_t new_pid
, pid
= ptid_get_lwp (ptid
);
917 if (linux_proc_pid_is_stopped (pid
))
920 fprintf_unfiltered (gdb_stdlog
,
921 "LNPAW: Attaching to a stopped process\n");
923 /* The process is definitely stopped. It is in a job control
924 stop, unless the kernel predates the TASK_STOPPED /
925 TASK_TRACED distinction, in which case it might be in a
926 ptrace stop. Make sure it is in a ptrace stop; from there we
927 can kill it, signal it, et cetera.
929 First make sure there is a pending SIGSTOP. Since we are
930 already attached, the process can not transition from stopped
931 to running without a PTRACE_CONT; so we know this signal will
932 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
933 probably already in the queue (unless this kernel is old
934 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
935 is not an RT signal, it can only be queued once. */
936 kill_lwp (pid
, SIGSTOP
);
938 /* Finally, resume the stopped process. This will deliver the SIGSTOP
939 (or a higher priority signal, just like normal PTRACE_ATTACH). */
940 ptrace (PTRACE_CONT
, pid
, 0, 0);
943 /* Make sure the initial process is stopped. The user-level threads
944 layer might want to poke around in the inferior, and that won't
945 work if things haven't stabilized yet. */
946 new_pid
= my_waitpid (pid
, &status
, 0);
947 if (new_pid
== -1 && errno
== ECHILD
)
950 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
952 /* Try again with __WCLONE to check cloned processes. */
953 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
957 gdb_assert (pid
== new_pid
);
959 if (!WIFSTOPPED (status
))
961 /* The pid we tried to attach has apparently just exited. */
963 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
964 pid
, status_to_str (status
));
968 if (WSTOPSIG (status
) != SIGSTOP
)
972 fprintf_unfiltered (gdb_stdlog
,
973 "LNPAW: Received %s after attaching\n",
974 status_to_str (status
));
980 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
981 the new LWP could not be attached, or 1 if we're already auto
982 attached to this thread, but haven't processed the
983 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
984 its existance, without considering it an error. */
987 lin_lwp_attach_lwp (ptid_t ptid
)
992 gdb_assert (ptid_lwp_p (ptid
));
994 lp
= find_lwp_pid (ptid
);
995 lwpid
= ptid_get_lwp (ptid
);
997 /* We assume that we're already attached to any LWP that has an id
998 equal to the overall process id, and to any LWP that is already
999 in our list of LWPs. If we're not seeing exit events from threads
1000 and we've had PID wraparound since we last tried to stop all threads,
1001 this assumption might be wrong; fortunately, this is very unlikely
1003 if (lwpid
!= ptid_get_pid (ptid
) && lp
== NULL
)
1005 int status
, cloned
= 0, signalled
= 0;
1007 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1009 if (linux_supports_tracefork ())
1011 /* If we haven't stopped all threads when we get here,
1012 we may have seen a thread listed in thread_db's list,
1013 but not processed the PTRACE_EVENT_CLONE yet. If
1014 that's the case, ignore this new thread, and let
1015 normal event handling discover it later. */
1016 if (in_pid_list_p (stopped_pids
, lwpid
))
1018 /* We've already seen this thread stop, but we
1019 haven't seen the PTRACE_EVENT_CLONE extended
1028 /* See if we've got a stop for this new child
1029 pending. If so, we're already attached. */
1030 gdb_assert (lwpid
> 0);
1031 new_pid
= my_waitpid (lwpid
, &status
, WNOHANG
);
1032 if (new_pid
== -1 && errno
== ECHILD
)
1033 new_pid
= my_waitpid (lwpid
, &status
, __WCLONE
| WNOHANG
);
1036 if (WIFSTOPPED (status
))
1037 add_to_pid_list (&stopped_pids
, lwpid
, status
);
1043 /* If we fail to attach to the thread, issue a warning,
1044 but continue. One way this can happen is if thread
1045 creation is interrupted; as of Linux kernel 2.6.19, a
1046 bug may place threads in the thread list and then fail
1048 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1049 safe_strerror (errno
));
1053 if (debug_linux_nat
)
1054 fprintf_unfiltered (gdb_stdlog
,
1055 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1056 target_pid_to_str (ptid
));
1058 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1059 if (!WIFSTOPPED (status
))
1062 lp
= add_lwp (ptid
);
1064 lp
->cloned
= cloned
;
1065 lp
->signalled
= signalled
;
1066 if (WSTOPSIG (status
) != SIGSTOP
)
1069 lp
->status
= status
;
1072 target_post_attach (ptid_get_lwp (lp
->ptid
));
1074 if (debug_linux_nat
)
1076 fprintf_unfiltered (gdb_stdlog
,
1077 "LLAL: waitpid %s received %s\n",
1078 target_pid_to_str (ptid
),
1079 status_to_str (status
));
1084 /* We assume that the LWP representing the original process is
1085 already stopped. Mark it as stopped in the data structure
1086 that the GNU/linux ptrace layer uses to keep track of
1087 threads. Note that this won't have already been done since
1088 the main thread will have, we assume, been stopped by an
1089 attach from a different layer. */
1091 lp
= add_lwp (ptid
);
1095 lp
->last_resume_kind
= resume_stop
;
1100 linux_nat_create_inferior (struct target_ops
*ops
,
1101 char *exec_file
, char *allargs
, char **env
,
1104 struct cleanup
*restore_personality
1105 = maybe_disable_address_space_randomization (disable_randomization
);
1107 /* The fork_child mechanism is synchronous and calls target_wait, so
1108 we have to mask the async mode. */
1110 /* Make sure we report all signals during startup. */
1111 linux_nat_pass_signals (ops
, 0, NULL
);
1113 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1115 do_cleanups (restore_personality
);
1118 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1119 already attached. Returns true if a new LWP is found, false
1123 attach_proc_task_lwp_callback (ptid_t ptid
)
1125 struct lwp_info
*lp
;
1127 /* Ignore LWPs we're already attached to. */
1128 lp
= find_lwp_pid (ptid
);
1131 int lwpid
= ptid_get_lwp (ptid
);
1133 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1137 /* Be quiet if we simply raced with the thread exiting.
1138 EPERM is returned if the thread's task still exists, and
1139 is marked as exited or zombie, as well as other
1140 conditions, so in that case, confirm the status in
1141 /proc/PID/status. */
1143 || (err
== EPERM
&& linux_proc_pid_is_gone (lwpid
)))
1145 if (debug_linux_nat
)
1147 fprintf_unfiltered (gdb_stdlog
,
1148 "Cannot attach to lwp %d: "
1149 "thread is gone (%d: %s)\n",
1150 lwpid
, err
, safe_strerror (err
));
1155 warning (_("Cannot attach to lwp %d: %s"),
1157 linux_ptrace_attach_fail_reason_string (ptid
,
1163 if (debug_linux_nat
)
1164 fprintf_unfiltered (gdb_stdlog
,
1165 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1166 target_pid_to_str (ptid
));
1168 lp
= add_lwp (ptid
);
1171 /* The next time we wait for this LWP we'll see a SIGSTOP as
1172 PTRACE_ATTACH brings it to a halt. */
1175 /* We need to wait for a stop before being able to make the
1176 next ptrace call on this LWP. */
1177 lp
->must_set_ptrace_flags
= 1;
1186 linux_nat_attach (struct target_ops
*ops
, const char *args
, int from_tty
)
1188 struct lwp_info
*lp
;
1191 volatile struct gdb_exception ex
;
1193 /* Make sure we report all signals during attach. */
1194 linux_nat_pass_signals (ops
, 0, NULL
);
1196 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
1198 linux_ops
->to_attach (ops
, args
, from_tty
);
1202 pid_t pid
= parse_pid_to_attach (args
);
1203 struct buffer buffer
;
1204 char *message
, *buffer_s
;
1206 message
= xstrdup (ex
.message
);
1207 make_cleanup (xfree
, message
);
1209 buffer_init (&buffer
);
1210 linux_ptrace_attach_fail_reason (pid
, &buffer
);
1212 buffer_grow_str0 (&buffer
, "");
1213 buffer_s
= buffer_finish (&buffer
);
1214 make_cleanup (xfree
, buffer_s
);
1216 if (*buffer_s
!= '\0')
1217 throw_error (ex
.error
, "warning: %s\n%s", buffer_s
, message
);
1219 throw_error (ex
.error
, "%s", message
);
1222 /* The ptrace base target adds the main thread with (pid,0,0)
1223 format. Decorate it with lwp info. */
1224 ptid
= ptid_build (ptid_get_pid (inferior_ptid
),
1225 ptid_get_pid (inferior_ptid
),
1227 thread_change_ptid (inferior_ptid
, ptid
);
1229 /* Add the initial process as the first LWP to the list. */
1230 lp
= add_initial_lwp (ptid
);
1232 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1234 if (!WIFSTOPPED (status
))
1236 if (WIFEXITED (status
))
1238 int exit_code
= WEXITSTATUS (status
);
1240 target_terminal_ours ();
1241 target_mourn_inferior ();
1243 error (_("Unable to attach: program exited normally."));
1245 error (_("Unable to attach: program exited with code %d."),
1248 else if (WIFSIGNALED (status
))
1250 enum gdb_signal signo
;
1252 target_terminal_ours ();
1253 target_mourn_inferior ();
1255 signo
= gdb_signal_from_host (WTERMSIG (status
));
1256 error (_("Unable to attach: program terminated with signal "
1258 gdb_signal_to_name (signo
),
1259 gdb_signal_to_string (signo
));
1262 internal_error (__FILE__
, __LINE__
,
1263 _("unexpected status %d for PID %ld"),
1264 status
, (long) ptid_get_lwp (ptid
));
1269 /* Save the wait status to report later. */
1271 if (debug_linux_nat
)
1272 fprintf_unfiltered (gdb_stdlog
,
1273 "LNA: waitpid %ld, saving status %s\n",
1274 (long) ptid_get_pid (lp
->ptid
), status_to_str (status
));
1276 lp
->status
= status
;
1278 /* We must attach to every LWP. If /proc is mounted, use that to
1279 find them now. The inferior may be using raw clone instead of
1280 using pthreads. But even if it is using pthreads, thread_db
1281 walks structures in the inferior's address space to find the list
1282 of threads/LWPs, and those structures may well be corrupted.
1283 Note that once thread_db is loaded, we'll still use it to list
1284 threads and associate pthread info with each LWP. */
1285 linux_proc_attach_tgid_threads (ptid_get_pid (lp
->ptid
),
1286 attach_proc_task_lwp_callback
);
1288 if (target_can_async_p ())
1289 target_async (inferior_event_handler
, 0);
1292 /* Get pending status of LP. */
1294 get_pending_status (struct lwp_info
*lp
, int *status
)
1296 enum gdb_signal signo
= GDB_SIGNAL_0
;
1298 /* If we paused threads momentarily, we may have stored pending
1299 events in lp->status or lp->waitstatus (see stop_wait_callback),
1300 and GDB core hasn't seen any signal for those threads.
1301 Otherwise, the last signal reported to the core is found in the
1302 thread object's stop_signal.
1304 There's a corner case that isn't handled here at present. Only
1305 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1306 stop_signal make sense as a real signal to pass to the inferior.
1307 Some catchpoint related events, like
1308 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1309 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1310 those traps are debug API (ptrace in our case) related and
1311 induced; the inferior wouldn't see them if it wasn't being
1312 traced. Hence, we should never pass them to the inferior, even
1313 when set to pass state. Since this corner case isn't handled by
1314 infrun.c when proceeding with a signal, for consistency, neither
1315 do we handle it here (or elsewhere in the file we check for
1316 signal pass state). Normally SIGTRAP isn't set to pass state, so
1317 this is really a corner case. */
1319 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1320 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1321 else if (lp
->status
)
1322 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1323 else if (non_stop
&& !is_executing (lp
->ptid
))
1325 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1327 signo
= tp
->suspend
.stop_signal
;
1331 struct target_waitstatus last
;
1334 get_last_target_status (&last_ptid
, &last
);
1336 if (ptid_get_lwp (lp
->ptid
) == ptid_get_lwp (last_ptid
))
1338 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1340 signo
= tp
->suspend
.stop_signal
;
1346 if (signo
== GDB_SIGNAL_0
)
1348 if (debug_linux_nat
)
1349 fprintf_unfiltered (gdb_stdlog
,
1350 "GPT: lwp %s has no pending signal\n",
1351 target_pid_to_str (lp
->ptid
));
1353 else if (!signal_pass_state (signo
))
1355 if (debug_linux_nat
)
1356 fprintf_unfiltered (gdb_stdlog
,
1357 "GPT: lwp %s had signal %s, "
1358 "but it is in no pass state\n",
1359 target_pid_to_str (lp
->ptid
),
1360 gdb_signal_to_string (signo
));
1364 *status
= W_STOPCODE (gdb_signal_to_host (signo
));
1366 if (debug_linux_nat
)
1367 fprintf_unfiltered (gdb_stdlog
,
1368 "GPT: lwp %s has pending signal %s\n",
1369 target_pid_to_str (lp
->ptid
),
1370 gdb_signal_to_string (signo
));
1377 detach_callback (struct lwp_info
*lp
, void *data
)
1379 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1381 if (debug_linux_nat
&& lp
->status
)
1382 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1383 strsignal (WSTOPSIG (lp
->status
)),
1384 target_pid_to_str (lp
->ptid
));
1386 /* If there is a pending SIGSTOP, get rid of it. */
1389 if (debug_linux_nat
)
1390 fprintf_unfiltered (gdb_stdlog
,
1391 "DC: Sending SIGCONT to %s\n",
1392 target_pid_to_str (lp
->ptid
));
1394 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGCONT
);
1398 /* We don't actually detach from the LWP that has an id equal to the
1399 overall process id just yet. */
1400 if (ptid_get_lwp (lp
->ptid
) != ptid_get_pid (lp
->ptid
))
1404 /* Pass on any pending signal for this LWP. */
1405 get_pending_status (lp
, &status
);
1407 if (linux_nat_prepare_to_resume
!= NULL
)
1408 linux_nat_prepare_to_resume (lp
);
1410 if (ptrace (PTRACE_DETACH
, ptid_get_lwp (lp
->ptid
), 0,
1411 WSTOPSIG (status
)) < 0)
1412 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1413 safe_strerror (errno
));
1415 if (debug_linux_nat
)
1416 fprintf_unfiltered (gdb_stdlog
,
1417 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1418 target_pid_to_str (lp
->ptid
),
1419 strsignal (WSTOPSIG (status
)));
1421 delete_lwp (lp
->ptid
);
1428 linux_nat_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1432 struct lwp_info
*main_lwp
;
1434 pid
= ptid_get_pid (inferior_ptid
);
1436 /* Don't unregister from the event loop, as there may be other
1437 inferiors running. */
1439 /* Stop all threads before detaching. ptrace requires that the
1440 thread is stopped to sucessfully detach. */
1441 iterate_over_lwps (pid_to_ptid (pid
), stop_callback
, NULL
);
1442 /* ... and wait until all of them have reported back that
1443 they're no longer running. */
1444 iterate_over_lwps (pid_to_ptid (pid
), stop_wait_callback
, NULL
);
1446 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1448 /* Only the initial process should be left right now. */
1449 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid
)) == 1);
1451 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
1453 /* Pass on any pending signal for the last LWP. */
1454 if ((args
== NULL
|| *args
== '\0')
1455 && get_pending_status (main_lwp
, &status
) != -1
1456 && WIFSTOPPED (status
))
1460 /* Put the signal number in ARGS so that inf_ptrace_detach will
1461 pass it along with PTRACE_DETACH. */
1463 xsnprintf (tem
, 8, "%d", (int) WSTOPSIG (status
));
1465 if (debug_linux_nat
)
1466 fprintf_unfiltered (gdb_stdlog
,
1467 "LND: Sending signal %s to %s\n",
1469 target_pid_to_str (main_lwp
->ptid
));
1472 if (linux_nat_prepare_to_resume
!= NULL
)
1473 linux_nat_prepare_to_resume (main_lwp
);
1474 delete_lwp (main_lwp
->ptid
);
1476 if (forks_exist_p ())
1478 /* Multi-fork case. The current inferior_ptid is being detached
1479 from, but there are other viable forks to debug. Detach from
1480 the current fork, and context-switch to the first
1482 linux_fork_detach (args
, from_tty
);
1485 linux_ops
->to_detach (ops
, args
, from_tty
);
1488 /* Resume execution of the inferior process. If STEP is nonzero,
1489 single-step it. If SIGNAL is nonzero, give it that signal. */
1492 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1498 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1499 We only presently need that if the LWP is stepped though (to
1500 handle the case of stepping a breakpoint instruction). */
1503 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
1505 lp
->stop_pc
= regcache_read_pc (regcache
);
1510 if (linux_nat_prepare_to_resume
!= NULL
)
1511 linux_nat_prepare_to_resume (lp
);
1512 /* Convert to something the lower layer understands. */
1513 ptid
= pid_to_ptid (ptid_get_lwp (lp
->ptid
));
1514 linux_ops
->to_resume (linux_ops
, ptid
, step
, signo
);
1515 lp
->stop_reason
= LWP_STOPPED_BY_NO_REASON
;
1517 registers_changed_ptid (lp
->ptid
);
1523 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1527 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
1529 if (inf
->vfork_child
!= NULL
)
1531 if (debug_linux_nat
)
1532 fprintf_unfiltered (gdb_stdlog
,
1533 "RC: Not resuming %s (vfork parent)\n",
1534 target_pid_to_str (lp
->ptid
));
1536 else if (!lwp_status_pending_p (lp
))
1538 if (debug_linux_nat
)
1539 fprintf_unfiltered (gdb_stdlog
,
1540 "RC: Resuming sibling %s, %s, %s\n",
1541 target_pid_to_str (lp
->ptid
),
1542 (signo
!= GDB_SIGNAL_0
1543 ? strsignal (gdb_signal_to_host (signo
))
1545 step
? "step" : "resume");
1547 linux_resume_one_lwp (lp
, step
, signo
);
1551 if (debug_linux_nat
)
1552 fprintf_unfiltered (gdb_stdlog
,
1553 "RC: Not resuming sibling %s (has pending)\n",
1554 target_pid_to_str (lp
->ptid
));
1559 if (debug_linux_nat
)
1560 fprintf_unfiltered (gdb_stdlog
,
1561 "RC: Not resuming sibling %s (not stopped)\n",
1562 target_pid_to_str (lp
->ptid
));
1566 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1567 Resume LWP with the last stop signal, if it is in pass state. */
1570 linux_nat_resume_callback (struct lwp_info
*lp
, void *except
)
1572 enum gdb_signal signo
= GDB_SIGNAL_0
;
1579 struct thread_info
*thread
;
1581 thread
= find_thread_ptid (lp
->ptid
);
1584 signo
= thread
->suspend
.stop_signal
;
1585 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1589 resume_lwp (lp
, 0, signo
);
1594 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1597 lp
->last_resume_kind
= resume_stop
;
1602 resume_set_callback (struct lwp_info
*lp
, void *data
)
1605 lp
->last_resume_kind
= resume_continue
;
1610 linux_nat_resume (struct target_ops
*ops
,
1611 ptid_t ptid
, int step
, enum gdb_signal signo
)
1613 struct lwp_info
*lp
;
1616 if (debug_linux_nat
)
1617 fprintf_unfiltered (gdb_stdlog
,
1618 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1619 step
? "step" : "resume",
1620 target_pid_to_str (ptid
),
1621 (signo
!= GDB_SIGNAL_0
1622 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1623 target_pid_to_str (inferior_ptid
));
1625 /* A specific PTID means `step only this process id'. */
1626 resume_many
= (ptid_equal (minus_one_ptid
, ptid
)
1627 || ptid_is_pid (ptid
));
1629 /* Mark the lwps we're resuming as resumed. */
1630 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1632 /* See if it's the current inferior that should be handled
1635 lp
= find_lwp_pid (inferior_ptid
);
1637 lp
= find_lwp_pid (ptid
);
1638 gdb_assert (lp
!= NULL
);
1640 /* Remember if we're stepping. */
1641 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1643 /* If we have a pending wait status for this thread, there is no
1644 point in resuming the process. But first make sure that
1645 linux_nat_wait won't preemptively handle the event - we
1646 should never take this short-circuit if we are going to
1647 leave LP running, since we have skipped resuming all the
1648 other threads. This bit of code needs to be synchronized
1649 with linux_nat_wait. */
1651 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1654 && WSTOPSIG (lp
->status
)
1655 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1657 if (debug_linux_nat
)
1658 fprintf_unfiltered (gdb_stdlog
,
1659 "LLR: Not short circuiting for ignored "
1660 "status 0x%x\n", lp
->status
);
1662 /* FIXME: What should we do if we are supposed to continue
1663 this thread with a signal? */
1664 gdb_assert (signo
== GDB_SIGNAL_0
);
1665 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1670 if (lwp_status_pending_p (lp
))
1672 /* FIXME: What should we do if we are supposed to continue
1673 this thread with a signal? */
1674 gdb_assert (signo
== GDB_SIGNAL_0
);
1676 if (debug_linux_nat
)
1677 fprintf_unfiltered (gdb_stdlog
,
1678 "LLR: Short circuiting for status 0x%x\n",
1681 if (target_can_async_p ())
1683 target_async (inferior_event_handler
, 0);
1684 /* Tell the event loop we have something to process. */
1691 iterate_over_lwps (ptid
, linux_nat_resume_callback
, lp
);
1693 linux_resume_one_lwp (lp
, step
, signo
);
1695 if (debug_linux_nat
)
1696 fprintf_unfiltered (gdb_stdlog
,
1697 "LLR: %s %s, %s (resume event thread)\n",
1698 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1699 target_pid_to_str (ptid
),
1700 (signo
!= GDB_SIGNAL_0
1701 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1703 if (target_can_async_p ())
1704 target_async (inferior_event_handler
, 0);
1707 /* Send a signal to an LWP. */
1710 kill_lwp (int lwpid
, int signo
)
1712 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1713 fails, then we are not using nptl threads and we should be using kill. */
1715 #ifdef HAVE_TKILL_SYSCALL
1717 static int tkill_failed
;
1724 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1725 if (errno
!= ENOSYS
)
1732 return kill (lwpid
, signo
);
1735 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1736 event, check if the core is interested in it: if not, ignore the
1737 event, and keep waiting; otherwise, we need to toggle the LWP's
1738 syscall entry/exit status, since the ptrace event itself doesn't
1739 indicate it, and report the trap to higher layers. */
1742 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1744 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1745 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1746 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, lp
->ptid
);
1750 /* If we're stopping threads, there's a SIGSTOP pending, which
1751 makes it so that the LWP reports an immediate syscall return,
1752 followed by the SIGSTOP. Skip seeing that "return" using
1753 PTRACE_CONT directly, and let stop_wait_callback collect the
1754 SIGSTOP. Later when the thread is resumed, a new syscall
1755 entry event. If we didn't do this (and returned 0), we'd
1756 leave a syscall entry pending, and our caller, by using
1757 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1758 itself. Later, when the user re-resumes this LWP, we'd see
1759 another syscall entry event and we'd mistake it for a return.
1761 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1762 (leaving immediately with LWP->signalled set, without issuing
1763 a PTRACE_CONT), it would still be problematic to leave this
1764 syscall enter pending, as later when the thread is resumed,
1765 it would then see the same syscall exit mentioned above,
1766 followed by the delayed SIGSTOP, while the syscall didn't
1767 actually get to execute. It seems it would be even more
1768 confusing to the user. */
1770 if (debug_linux_nat
)
1771 fprintf_unfiltered (gdb_stdlog
,
1772 "LHST: ignoring syscall %d "
1773 "for LWP %ld (stopping threads), "
1774 "resuming with PTRACE_CONT for SIGSTOP\n",
1776 ptid_get_lwp (lp
->ptid
));
1778 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1779 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
1784 if (catch_syscall_enabled ())
1786 /* Always update the entry/return state, even if this particular
1787 syscall isn't interesting to the core now. In async mode,
1788 the user could install a new catchpoint for this syscall
1789 between syscall enter/return, and we'll need to know to
1790 report a syscall return if that happens. */
1791 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1792 ? TARGET_WAITKIND_SYSCALL_RETURN
1793 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1795 if (catching_syscall_number (syscall_number
))
1797 /* Alright, an event to report. */
1798 ourstatus
->kind
= lp
->syscall_state
;
1799 ourstatus
->value
.syscall_number
= syscall_number
;
1801 if (debug_linux_nat
)
1802 fprintf_unfiltered (gdb_stdlog
,
1803 "LHST: stopping for %s of syscall %d"
1806 == TARGET_WAITKIND_SYSCALL_ENTRY
1807 ? "entry" : "return",
1809 ptid_get_lwp (lp
->ptid
));
1813 if (debug_linux_nat
)
1814 fprintf_unfiltered (gdb_stdlog
,
1815 "LHST: ignoring %s of syscall %d "
1817 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1818 ? "entry" : "return",
1820 ptid_get_lwp (lp
->ptid
));
1824 /* If we had been syscall tracing, and hence used PT_SYSCALL
1825 before on this LWP, it could happen that the user removes all
1826 syscall catchpoints before we get to process this event.
1827 There are two noteworthy issues here:
1829 - When stopped at a syscall entry event, resuming with
1830 PT_STEP still resumes executing the syscall and reports a
1833 - Only PT_SYSCALL catches syscall enters. If we last
1834 single-stepped this thread, then this event can't be a
1835 syscall enter. If we last single-stepped this thread, this
1836 has to be a syscall exit.
1838 The points above mean that the next resume, be it PT_STEP or
1839 PT_CONTINUE, can not trigger a syscall trace event. */
1840 if (debug_linux_nat
)
1841 fprintf_unfiltered (gdb_stdlog
,
1842 "LHST: caught syscall event "
1843 "with no syscall catchpoints."
1844 " %d for LWP %ld, ignoring\n",
1846 ptid_get_lwp (lp
->ptid
));
1847 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1850 /* The core isn't interested in this event. For efficiency, avoid
1851 stopping all threads only to have the core resume them all again.
1852 Since we're not stopping threads, if we're still syscall tracing
1853 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1854 subsequent syscall. Simply resume using the inf-ptrace layer,
1855 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1857 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1861 /* Handle a GNU/Linux extended wait response. If we see a clone
1862 event, we need to add the new LWP to our list (and not report the
1863 trap to higher layers). This function returns non-zero if the
1864 event should be ignored and we should wait again. If STOPPING is
1865 true, the new LWP remains stopped, otherwise it is continued. */
1868 linux_handle_extended_wait (struct lwp_info
*lp
, int status
,
1871 int pid
= ptid_get_lwp (lp
->ptid
);
1872 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1873 int event
= linux_ptrace_get_extended_event (status
);
1875 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1876 || event
== PTRACE_EVENT_CLONE
)
1878 unsigned long new_pid
;
1881 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1883 /* If we haven't already seen the new PID stop, wait for it now. */
1884 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1886 /* The new child has a pending SIGSTOP. We can't affect it until it
1887 hits the SIGSTOP, but we're already attached. */
1888 ret
= my_waitpid (new_pid
, &status
,
1889 (event
== PTRACE_EVENT_CLONE
) ? __WCLONE
: 0);
1891 perror_with_name (_("waiting for new child"));
1892 else if (ret
!= new_pid
)
1893 internal_error (__FILE__
, __LINE__
,
1894 _("wait returned unexpected PID %d"), ret
);
1895 else if (!WIFSTOPPED (status
))
1896 internal_error (__FILE__
, __LINE__
,
1897 _("wait returned unexpected status 0x%x"), status
);
1900 ourstatus
->value
.related_pid
= ptid_build (new_pid
, new_pid
, 0);
1902 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1904 /* The arch-specific native code may need to know about new
1905 forks even if those end up never mapped to an
1907 if (linux_nat_new_fork
!= NULL
)
1908 linux_nat_new_fork (lp
, new_pid
);
1911 if (event
== PTRACE_EVENT_FORK
1912 && linux_fork_checkpointing_p (ptid_get_pid (lp
->ptid
)))
1914 /* Handle checkpointing by linux-fork.c here as a special
1915 case. We don't want the follow-fork-mode or 'catch fork'
1916 to interfere with this. */
1918 /* This won't actually modify the breakpoint list, but will
1919 physically remove the breakpoints from the child. */
1920 detach_breakpoints (ptid_build (new_pid
, new_pid
, 0));
1922 /* Retain child fork in ptrace (stopped) state. */
1923 if (!find_fork_pid (new_pid
))
1926 /* Report as spurious, so that infrun doesn't want to follow
1927 this fork. We're actually doing an infcall in
1929 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
1931 /* Report the stop to the core. */
1935 if (event
== PTRACE_EVENT_FORK
)
1936 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
1937 else if (event
== PTRACE_EVENT_VFORK
)
1938 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
1941 struct lwp_info
*new_lp
;
1943 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
1945 if (debug_linux_nat
)
1946 fprintf_unfiltered (gdb_stdlog
,
1947 "LHEW: Got clone event "
1948 "from LWP %d, new child is LWP %ld\n",
1951 new_lp
= add_lwp (ptid_build (ptid_get_pid (lp
->ptid
), new_pid
, 0));
1953 new_lp
->stopped
= 1;
1955 if (WSTOPSIG (status
) != SIGSTOP
)
1957 /* This can happen if someone starts sending signals to
1958 the new thread before it gets a chance to run, which
1959 have a lower number than SIGSTOP (e.g. SIGUSR1).
1960 This is an unlikely case, and harder to handle for
1961 fork / vfork than for clone, so we do not try - but
1962 we handle it for clone events here. We'll send
1963 the other signal on to the thread below. */
1965 new_lp
->signalled
= 1;
1969 struct thread_info
*tp
;
1971 /* When we stop for an event in some other thread, and
1972 pull the thread list just as this thread has cloned,
1973 we'll have seen the new thread in the thread_db list
1974 before handling the CLONE event (glibc's
1975 pthread_create adds the new thread to the thread list
1976 before clone'ing, and has the kernel fill in the
1977 thread's tid on the clone call with
1978 CLONE_PARENT_SETTID). If that happened, and the core
1979 had requested the new thread to stop, we'll have
1980 killed it with SIGSTOP. But since SIGSTOP is not an
1981 RT signal, it can only be queued once. We need to be
1982 careful to not resume the LWP if we wanted it to
1983 stop. In that case, we'll leave the SIGSTOP pending.
1984 It will later be reported as GDB_SIGNAL_0. */
1985 tp
= find_thread_ptid (new_lp
->ptid
);
1986 if (tp
!= NULL
&& tp
->stop_requested
)
1987 new_lp
->last_resume_kind
= resume_stop
;
1994 /* Add the new thread to GDB's lists as soon as possible
1997 1) the frontend doesn't have to wait for a stop to
2000 2) we tag it with the correct running state. */
2002 /* If the thread_db layer is active, let it know about
2003 this new thread, and add it to GDB's list. */
2004 if (!thread_db_attach_lwp (new_lp
->ptid
))
2006 /* We're not using thread_db. Add it to GDB's
2008 target_post_attach (ptid_get_lwp (new_lp
->ptid
));
2009 add_thread (new_lp
->ptid
);
2014 set_running (new_lp
->ptid
, 1);
2015 set_executing (new_lp
->ptid
, 1);
2016 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2018 new_lp
->last_resume_kind
= resume_continue
;
2024 /* We created NEW_LP so it cannot yet contain STATUS. */
2025 gdb_assert (new_lp
->status
== 0);
2027 /* Save the wait status to report later. */
2028 if (debug_linux_nat
)
2029 fprintf_unfiltered (gdb_stdlog
,
2030 "LHEW: waitpid of new LWP %ld, "
2031 "saving status %s\n",
2032 (long) ptid_get_lwp (new_lp
->ptid
),
2033 status_to_str (status
));
2034 new_lp
->status
= status
;
2037 new_lp
->resumed
= !stopping
;
2044 if (event
== PTRACE_EVENT_EXEC
)
2046 if (debug_linux_nat
)
2047 fprintf_unfiltered (gdb_stdlog
,
2048 "LHEW: Got exec event from LWP %ld\n",
2049 ptid_get_lwp (lp
->ptid
));
2051 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2052 ourstatus
->value
.execd_pathname
2053 = xstrdup (linux_child_pid_to_exec_file (NULL
, pid
));
2055 /* The thread that execed must have been resumed, but, when a
2056 thread execs, it changes its tid to the tgid, and the old
2057 tgid thread might have not been resumed. */
2062 if (event
== PTRACE_EVENT_VFORK_DONE
)
2064 if (current_inferior ()->waiting_for_vfork_done
)
2066 if (debug_linux_nat
)
2067 fprintf_unfiltered (gdb_stdlog
,
2068 "LHEW: Got expected PTRACE_EVENT_"
2069 "VFORK_DONE from LWP %ld: stopping\n",
2070 ptid_get_lwp (lp
->ptid
));
2072 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2076 if (debug_linux_nat
)
2077 fprintf_unfiltered (gdb_stdlog
,
2078 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2079 "from LWP %ld: ignoring\n",
2080 ptid_get_lwp (lp
->ptid
));
2084 internal_error (__FILE__
, __LINE__
,
2085 _("unknown ptrace event %d"), event
);
2088 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2092 wait_lwp (struct lwp_info
*lp
)
2096 int thread_dead
= 0;
2099 gdb_assert (!lp
->stopped
);
2100 gdb_assert (lp
->status
== 0);
2102 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2103 block_child_signals (&prev_mask
);
2107 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2108 was right and we should just call sigsuspend. */
2110 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, WNOHANG
);
2111 if (pid
== -1 && errno
== ECHILD
)
2112 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, __WCLONE
| WNOHANG
);
2113 if (pid
== -1 && errno
== ECHILD
)
2115 /* The thread has previously exited. We need to delete it
2116 now because, for some vendor 2.4 kernels with NPTL
2117 support backported, there won't be an exit event unless
2118 it is the main thread. 2.6 kernels will report an exit
2119 event for each thread that exits, as expected. */
2121 if (debug_linux_nat
)
2122 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2123 target_pid_to_str (lp
->ptid
));
2128 /* Bugs 10970, 12702.
2129 Thread group leader may have exited in which case we'll lock up in
2130 waitpid if there are other threads, even if they are all zombies too.
2131 Basically, we're not supposed to use waitpid this way.
2132 __WCLONE is not applicable for the leader so we can't use that.
2133 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2134 process; it gets ESRCH both for the zombie and for running processes.
2136 As a workaround, check if we're waiting for the thread group leader and
2137 if it's a zombie, and avoid calling waitpid if it is.
2139 This is racy, what if the tgl becomes a zombie right after we check?
2140 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2141 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2143 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
)
2144 && linux_proc_pid_is_zombie (ptid_get_lwp (lp
->ptid
)))
2147 if (debug_linux_nat
)
2148 fprintf_unfiltered (gdb_stdlog
,
2149 "WL: Thread group leader %s vanished.\n",
2150 target_pid_to_str (lp
->ptid
));
2154 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2155 get invoked despite our caller had them intentionally blocked by
2156 block_child_signals. This is sensitive only to the loop of
2157 linux_nat_wait_1 and there if we get called my_waitpid gets called
2158 again before it gets to sigsuspend so we can safely let the handlers
2159 get executed here. */
2161 if (debug_linux_nat
)
2162 fprintf_unfiltered (gdb_stdlog
, "WL: about to sigsuspend\n");
2163 sigsuspend (&suspend_mask
);
2166 restore_child_signals_mask (&prev_mask
);
2170 gdb_assert (pid
== ptid_get_lwp (lp
->ptid
));
2172 if (debug_linux_nat
)
2174 fprintf_unfiltered (gdb_stdlog
,
2175 "WL: waitpid %s received %s\n",
2176 target_pid_to_str (lp
->ptid
),
2177 status_to_str (status
));
2180 /* Check if the thread has exited. */
2181 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2184 if (debug_linux_nat
)
2185 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2186 target_pid_to_str (lp
->ptid
));
2196 gdb_assert (WIFSTOPPED (status
));
2199 if (lp
->must_set_ptrace_flags
)
2201 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2203 linux_enable_event_reporting (ptid_get_lwp (lp
->ptid
), inf
->attach_flag
);
2204 lp
->must_set_ptrace_flags
= 0;
2207 /* Handle GNU/Linux's syscall SIGTRAPs. */
2208 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2210 /* No longer need the sysgood bit. The ptrace event ends up
2211 recorded in lp->waitstatus if we care for it. We can carry
2212 on handling the event like a regular SIGTRAP from here
2214 status
= W_STOPCODE (SIGTRAP
);
2215 if (linux_handle_syscall_trap (lp
, 1))
2216 return wait_lwp (lp
);
2219 /* Handle GNU/Linux's extended waitstatus for trace events. */
2220 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2221 && linux_is_extended_waitstatus (status
))
2223 if (debug_linux_nat
)
2224 fprintf_unfiltered (gdb_stdlog
,
2225 "WL: Handling extended status 0x%06x\n",
2227 linux_handle_extended_wait (lp
, status
, 1);
2234 /* Send a SIGSTOP to LP. */
2237 stop_callback (struct lwp_info
*lp
, void *data
)
2239 if (!lp
->stopped
&& !lp
->signalled
)
2243 if (debug_linux_nat
)
2245 fprintf_unfiltered (gdb_stdlog
,
2246 "SC: kill %s **<SIGSTOP>**\n",
2247 target_pid_to_str (lp
->ptid
));
2250 ret
= kill_lwp (ptid_get_lwp (lp
->ptid
), SIGSTOP
);
2251 if (debug_linux_nat
)
2253 fprintf_unfiltered (gdb_stdlog
,
2254 "SC: lwp kill %d %s\n",
2256 errno
? safe_strerror (errno
) : "ERRNO-OK");
2260 gdb_assert (lp
->status
== 0);
2266 /* Request a stop on LWP. */
2269 linux_stop_lwp (struct lwp_info
*lwp
)
2271 stop_callback (lwp
, NULL
);
2274 /* Return non-zero if LWP PID has a pending SIGINT. */
2277 linux_nat_has_pending_sigint (int pid
)
2279 sigset_t pending
, blocked
, ignored
;
2281 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2283 if (sigismember (&pending
, SIGINT
)
2284 && !sigismember (&ignored
, SIGINT
))
2290 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2293 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2295 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2296 flag to consume the next one. */
2297 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2298 && WSTOPSIG (lp
->status
) == SIGINT
)
2301 lp
->ignore_sigint
= 1;
2306 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2307 This function is called after we know the LWP has stopped; if the LWP
2308 stopped before the expected SIGINT was delivered, then it will never have
2309 arrived. Also, if the signal was delivered to a shared queue and consumed
2310 by a different thread, it will never be delivered to this LWP. */
2313 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2315 if (!lp
->ignore_sigint
)
2318 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp
->ptid
)))
2320 if (debug_linux_nat
)
2321 fprintf_unfiltered (gdb_stdlog
,
2322 "MCIS: Clearing bogus flag for %s\n",
2323 target_pid_to_str (lp
->ptid
));
2324 lp
->ignore_sigint
= 0;
2328 /* Fetch the possible triggered data watchpoint info and store it in
2331 On some archs, like x86, that use debug registers to set
2332 watchpoints, it's possible that the way to know which watched
2333 address trapped, is to check the register that is used to select
2334 which address to watch. Problem is, between setting the watchpoint
2335 and reading back which data address trapped, the user may change
2336 the set of watchpoints, and, as a consequence, GDB changes the
2337 debug registers in the inferior. To avoid reading back a stale
2338 stopped-data-address when that happens, we cache in LP the fact
2339 that a watchpoint trapped, and the corresponding data address, as
2340 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2341 registers meanwhile, we have the cached data we can rely on. */
2344 check_stopped_by_watchpoint (struct lwp_info
*lp
)
2346 struct cleanup
*old_chain
;
2348 if (linux_ops
->to_stopped_by_watchpoint
== NULL
)
2351 old_chain
= save_inferior_ptid ();
2352 inferior_ptid
= lp
->ptid
;
2354 if (linux_ops
->to_stopped_by_watchpoint (linux_ops
))
2356 lp
->stop_reason
= LWP_STOPPED_BY_WATCHPOINT
;
2358 if (linux_ops
->to_stopped_data_address
!= NULL
)
2359 lp
->stopped_data_address_p
=
2360 linux_ops
->to_stopped_data_address (¤t_target
,
2361 &lp
->stopped_data_address
);
2363 lp
->stopped_data_address_p
= 0;
2366 do_cleanups (old_chain
);
2368 return lp
->stop_reason
== LWP_STOPPED_BY_WATCHPOINT
;
2371 /* Called when the LWP stopped for a trap that could be explained by a
2372 watchpoint or a breakpoint. */
2375 save_sigtrap (struct lwp_info
*lp
)
2377 gdb_assert (lp
->stop_reason
== LWP_STOPPED_BY_NO_REASON
);
2378 gdb_assert (lp
->status
!= 0);
2380 if (check_stopped_by_watchpoint (lp
))
2383 if (linux_nat_status_is_event (lp
->status
))
2384 check_stopped_by_breakpoint (lp
);
2387 /* Returns true if the LWP had stopped for a watchpoint. */
2390 linux_nat_stopped_by_watchpoint (struct target_ops
*ops
)
2392 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2394 gdb_assert (lp
!= NULL
);
2396 return lp
->stop_reason
== LWP_STOPPED_BY_WATCHPOINT
;
2400 linux_nat_stopped_data_address (struct target_ops
*ops
, CORE_ADDR
*addr_p
)
2402 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2404 gdb_assert (lp
!= NULL
);
2406 *addr_p
= lp
->stopped_data_address
;
2408 return lp
->stopped_data_address_p
;
2411 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2414 sigtrap_is_event (int status
)
2416 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2419 /* Set alternative SIGTRAP-like events recognizer. If
2420 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2424 linux_nat_set_status_is_event (struct target_ops
*t
,
2425 int (*status_is_event
) (int status
))
2427 linux_nat_status_is_event
= status_is_event
;
2430 /* Wait until LP is stopped. */
2433 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2435 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
2437 /* If this is a vfork parent, bail out, it is not going to report
2438 any SIGSTOP until the vfork is done with. */
2439 if (inf
->vfork_child
!= NULL
)
2446 status
= wait_lwp (lp
);
2450 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2451 && WSTOPSIG (status
) == SIGINT
)
2453 lp
->ignore_sigint
= 0;
2456 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2458 if (debug_linux_nat
)
2459 fprintf_unfiltered (gdb_stdlog
,
2460 "PTRACE_CONT %s, 0, 0 (%s) "
2461 "(discarding SIGINT)\n",
2462 target_pid_to_str (lp
->ptid
),
2463 errno
? safe_strerror (errno
) : "OK");
2465 return stop_wait_callback (lp
, NULL
);
2468 maybe_clear_ignore_sigint (lp
);
2470 if (WSTOPSIG (status
) != SIGSTOP
)
2472 /* The thread was stopped with a signal other than SIGSTOP. */
2474 if (debug_linux_nat
)
2475 fprintf_unfiltered (gdb_stdlog
,
2476 "SWC: Pending event %s in %s\n",
2477 status_to_str ((int) status
),
2478 target_pid_to_str (lp
->ptid
));
2480 /* Save the sigtrap event. */
2481 lp
->status
= status
;
2482 gdb_assert (lp
->signalled
);
2487 /* We caught the SIGSTOP that we intended to catch, so
2488 there's no SIGSTOP pending. */
2490 if (debug_linux_nat
)
2491 fprintf_unfiltered (gdb_stdlog
,
2492 "SWC: Delayed SIGSTOP caught for %s.\n",
2493 target_pid_to_str (lp
->ptid
));
2495 /* Reset SIGNALLED only after the stop_wait_callback call
2496 above as it does gdb_assert on SIGNALLED. */
2504 /* Return non-zero if LP has a wait status pending. Discard the
2505 pending event and resume the LWP if the event that originally
2506 caused the stop became uninteresting. */
2509 status_callback (struct lwp_info
*lp
, void *data
)
2511 /* Only report a pending wait status if we pretend that this has
2512 indeed been resumed. */
2516 if (lp
->stop_reason
== LWP_STOPPED_BY_SW_BREAKPOINT
2517 || lp
->stop_reason
== LWP_STOPPED_BY_HW_BREAKPOINT
)
2519 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2520 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2524 gdb_assert (lp
->status
!= 0);
2526 pc
= regcache_read_pc (regcache
);
2528 if (pc
!= lp
->stop_pc
)
2530 if (debug_linux_nat
)
2531 fprintf_unfiltered (gdb_stdlog
,
2532 "SC: PC of %s changed. was=%s, now=%s\n",
2533 target_pid_to_str (lp
->ptid
),
2534 paddress (target_gdbarch (), lp
->stop_pc
),
2535 paddress (target_gdbarch (), pc
));
2538 else if (!breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2540 if (debug_linux_nat
)
2541 fprintf_unfiltered (gdb_stdlog
,
2542 "SC: previous breakpoint of %s, at %s gone\n",
2543 target_pid_to_str (lp
->ptid
),
2544 paddress (target_gdbarch (), lp
->stop_pc
));
2551 if (debug_linux_nat
)
2552 fprintf_unfiltered (gdb_stdlog
,
2553 "SC: pending event of %s cancelled.\n",
2554 target_pid_to_str (lp
->ptid
));
2557 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2563 return lwp_status_pending_p (lp
);
2566 /* Return non-zero if LP isn't stopped. */
2569 running_callback (struct lwp_info
*lp
, void *data
)
2571 return (!lp
->stopped
2572 || (lwp_status_pending_p (lp
) && lp
->resumed
));
2575 /* Count the LWP's that have had events. */
2578 count_events_callback (struct lwp_info
*lp
, void *data
)
2582 gdb_assert (count
!= NULL
);
2584 /* Select only resumed LWPs that have an event pending. */
2585 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2591 /* Select the LWP (if any) that is currently being single-stepped. */
2594 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2596 if (lp
->last_resume_kind
== resume_step
2603 /* Returns true if LP has a status pending. */
2606 lwp_status_pending_p (struct lwp_info
*lp
)
2608 /* We check for lp->waitstatus in addition to lp->status, because we
2609 can have pending process exits recorded in lp->status and
2610 W_EXITCODE(0,0) happens to be 0. */
2611 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2614 /* Select the Nth LWP that has had a SIGTRAP event. */
2617 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2619 int *selector
= data
;
2621 gdb_assert (selector
!= NULL
);
2623 /* Select only resumed LWPs that have an event pending. */
2624 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2625 if ((*selector
)-- == 0)
2631 /* Called when the LWP got a signal/trap that could be explained by a
2632 software or hardware breakpoint. */
2635 check_stopped_by_breakpoint (struct lwp_info
*lp
)
2637 /* Arrange for a breakpoint to be hit again later. We don't keep
2638 the SIGTRAP status and don't forward the SIGTRAP signal to the
2639 LWP. We will handle the current event, eventually we will resume
2640 this LWP, and this breakpoint will trap again.
2642 If we do not do this, then we run the risk that the user will
2643 delete or disable the breakpoint, but the LWP will have already
2646 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2647 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2651 pc
= regcache_read_pc (regcache
);
2652 sw_bp_pc
= pc
- target_decr_pc_after_break (gdbarch
);
2654 if ((!lp
->step
|| lp
->stop_pc
== sw_bp_pc
)
2655 && software_breakpoint_inserted_here_p (get_regcache_aspace (regcache
),
2658 /* The LWP was either continued, or stepped a software
2659 breakpoint instruction. */
2660 if (debug_linux_nat
)
2661 fprintf_unfiltered (gdb_stdlog
,
2662 "CB: Push back software breakpoint for %s\n",
2663 target_pid_to_str (lp
->ptid
));
2665 /* Back up the PC if necessary. */
2667 regcache_write_pc (regcache
, sw_bp_pc
);
2669 lp
->stop_pc
= sw_bp_pc
;
2670 lp
->stop_reason
= LWP_STOPPED_BY_SW_BREAKPOINT
;
2674 if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2676 if (debug_linux_nat
)
2677 fprintf_unfiltered (gdb_stdlog
,
2678 "CB: Push back hardware breakpoint for %s\n",
2679 target_pid_to_str (lp
->ptid
));
2682 lp
->stop_reason
= LWP_STOPPED_BY_HW_BREAKPOINT
;
2689 /* Select one LWP out of those that have events pending. */
2692 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2695 int random_selector
;
2696 struct lwp_info
*event_lp
= NULL
;
2698 /* Record the wait status for the original LWP. */
2699 (*orig_lp
)->status
= *status
;
2701 /* In all-stop, give preference to the LWP that is being
2702 single-stepped. There will be at most one, and it will be the
2703 LWP that the core is most interested in. If we didn't do this,
2704 then we'd have to handle pending step SIGTRAPs somehow in case
2705 the core later continues the previously-stepped thread, as
2706 otherwise we'd report the pending SIGTRAP then, and the core, not
2707 having stepped the thread, wouldn't understand what the trap was
2708 for, and therefore would report it to the user as a random
2712 event_lp
= iterate_over_lwps (filter
,
2713 select_singlestep_lwp_callback
, NULL
);
2714 if (event_lp
!= NULL
)
2716 if (debug_linux_nat
)
2717 fprintf_unfiltered (gdb_stdlog
,
2718 "SEL: Select single-step %s\n",
2719 target_pid_to_str (event_lp
->ptid
));
2723 if (event_lp
== NULL
)
2725 /* Pick one at random, out of those which have had events. */
2727 /* First see how many events we have. */
2728 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2730 /* Now randomly pick a LWP out of those that have had
2732 random_selector
= (int)
2733 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2735 if (debug_linux_nat
&& num_events
> 1)
2736 fprintf_unfiltered (gdb_stdlog
,
2737 "SEL: Found %d events, selecting #%d\n",
2738 num_events
, random_selector
);
2740 event_lp
= iterate_over_lwps (filter
,
2741 select_event_lwp_callback
,
2745 if (event_lp
!= NULL
)
2747 /* Switch the event LWP. */
2748 *orig_lp
= event_lp
;
2749 *status
= event_lp
->status
;
2752 /* Flush the wait status for the event LWP. */
2753 (*orig_lp
)->status
= 0;
2756 /* Return non-zero if LP has been resumed. */
2759 resumed_callback (struct lwp_info
*lp
, void *data
)
2764 /* Stop an active thread, verify it still exists, then resume it. If
2765 the thread ends up with a pending status, then it is not resumed,
2766 and *DATA (really a pointer to int), is set. */
2769 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2773 ptid_t ptid
= lp
->ptid
;
2775 stop_callback (lp
, NULL
);
2776 stop_wait_callback (lp
, NULL
);
2778 /* Resume if the lwp still exists, and the core wanted it
2780 lp
= find_lwp_pid (ptid
);
2783 if (lp
->last_resume_kind
== resume_stop
2784 && !lwp_status_pending_p (lp
))
2786 /* The core wanted the LWP to stop. Even if it stopped
2787 cleanly (with SIGSTOP), leave the event pending. */
2788 if (debug_linux_nat
)
2789 fprintf_unfiltered (gdb_stdlog
,
2790 "SARC: core wanted LWP %ld stopped "
2791 "(leaving SIGSTOP pending)\n",
2792 ptid_get_lwp (lp
->ptid
));
2793 lp
->status
= W_STOPCODE (SIGSTOP
);
2796 if (!lwp_status_pending_p (lp
))
2798 if (debug_linux_nat
)
2799 fprintf_unfiltered (gdb_stdlog
,
2800 "SARC: re-resuming LWP %ld\n",
2801 ptid_get_lwp (lp
->ptid
));
2802 resume_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2806 if (debug_linux_nat
)
2807 fprintf_unfiltered (gdb_stdlog
,
2808 "SARC: not re-resuming LWP %ld "
2810 ptid_get_lwp (lp
->ptid
));
2817 /* Check if we should go on and pass this event to common code.
2818 Return the affected lwp if we are, or NULL otherwise. */
2820 static struct lwp_info
*
2821 linux_nat_filter_event (int lwpid
, int status
)
2823 struct lwp_info
*lp
;
2824 int event
= linux_ptrace_get_extended_event (status
);
2826 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2828 /* Check for stop events reported by a process we didn't already
2829 know about - anything not already in our LWP list.
2831 If we're expecting to receive stopped processes after
2832 fork, vfork, and clone events, then we'll just add the
2833 new one to our list and go back to waiting for the event
2834 to be reported - the stopped process might be returned
2835 from waitpid before or after the event is.
2837 But note the case of a non-leader thread exec'ing after the
2838 leader having exited, and gone from our lists. The non-leader
2839 thread changes its tid to the tgid. */
2841 if (WIFSTOPPED (status
) && lp
== NULL
2842 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2844 /* A multi-thread exec after we had seen the leader exiting. */
2845 if (debug_linux_nat
)
2846 fprintf_unfiltered (gdb_stdlog
,
2847 "LLW: Re-adding thread group leader LWP %d.\n",
2850 lp
= add_lwp (ptid_build (lwpid
, lwpid
, 0));
2853 add_thread (lp
->ptid
);
2856 if (WIFSTOPPED (status
) && !lp
)
2858 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2862 /* Make sure we don't report an event for the exit of an LWP not in
2863 our list, i.e. not part of the current process. This can happen
2864 if we detach from a program we originally forked and then it
2866 if (!WIFSTOPPED (status
) && !lp
)
2869 /* This LWP is stopped now. (And if dead, this prevents it from
2870 ever being continued.) */
2873 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2875 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2877 linux_enable_event_reporting (ptid_get_lwp (lp
->ptid
), inf
->attach_flag
);
2878 lp
->must_set_ptrace_flags
= 0;
2881 /* Handle GNU/Linux's syscall SIGTRAPs. */
2882 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2884 /* No longer need the sysgood bit. The ptrace event ends up
2885 recorded in lp->waitstatus if we care for it. We can carry
2886 on handling the event like a regular SIGTRAP from here
2888 status
= W_STOPCODE (SIGTRAP
);
2889 if (linux_handle_syscall_trap (lp
, 0))
2893 /* Handle GNU/Linux's extended waitstatus for trace events. */
2894 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2895 && linux_is_extended_waitstatus (status
))
2897 if (debug_linux_nat
)
2898 fprintf_unfiltered (gdb_stdlog
,
2899 "LLW: Handling extended status 0x%06x\n",
2901 if (linux_handle_extended_wait (lp
, status
, 0))
2905 /* Check if the thread has exited. */
2906 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2908 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2910 /* If this is the main thread, we must stop all threads and
2911 verify if they are still alive. This is because in the
2912 nptl thread model on Linux 2.4, there is no signal issued
2913 for exiting LWPs other than the main thread. We only get
2914 the main thread exit signal once all child threads have
2915 already exited. If we stop all the threads and use the
2916 stop_wait_callback to check if they have exited we can
2917 determine whether this signal should be ignored or
2918 whether it means the end of the debugged application,
2919 regardless of which threading model is being used. */
2920 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
))
2922 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
2923 stop_and_resume_callback
, NULL
);
2926 if (debug_linux_nat
)
2927 fprintf_unfiltered (gdb_stdlog
,
2928 "LLW: %s exited.\n",
2929 target_pid_to_str (lp
->ptid
));
2931 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2933 /* If there is at least one more LWP, then the exit signal
2934 was not the end of the debugged application and should be
2941 gdb_assert (lp
->resumed
);
2943 if (debug_linux_nat
)
2944 fprintf_unfiltered (gdb_stdlog
,
2945 "Process %ld exited\n",
2946 ptid_get_lwp (lp
->ptid
));
2948 /* This was the last lwp in the process. Since events are
2949 serialized to GDB core, we may not be able report this one
2950 right now, but GDB core and the other target layers will want
2951 to be notified about the exit code/signal, leave the status
2952 pending for the next time we're able to report it. */
2954 /* Dead LWP's aren't expected to reported a pending sigstop. */
2957 /* Store the pending event in the waitstatus, because
2958 W_EXITCODE(0,0) == 0. */
2959 store_waitstatus (&lp
->waitstatus
, status
);
2963 /* Check if the current LWP has previously exited. In the nptl
2964 thread model, LWPs other than the main thread do not issue
2965 signals when they exit so we must check whenever the thread has
2966 stopped. A similar check is made in stop_wait_callback(). */
2967 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1 && !linux_thread_alive (lp
->ptid
))
2969 ptid_t ptid
= pid_to_ptid (ptid_get_pid (lp
->ptid
));
2971 if (debug_linux_nat
)
2972 fprintf_unfiltered (gdb_stdlog
,
2973 "LLW: %s exited.\n",
2974 target_pid_to_str (lp
->ptid
));
2978 /* Make sure there is at least one thread running. */
2979 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
2981 /* Discard the event. */
2985 /* Make sure we don't report a SIGSTOP that we sent ourselves in
2986 an attempt to stop an LWP. */
2988 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
2990 if (debug_linux_nat
)
2991 fprintf_unfiltered (gdb_stdlog
,
2992 "LLW: Delayed SIGSTOP caught for %s.\n",
2993 target_pid_to_str (lp
->ptid
));
2997 if (lp
->last_resume_kind
!= resume_stop
)
2999 /* This is a delayed SIGSTOP. */
3001 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3002 if (debug_linux_nat
)
3003 fprintf_unfiltered (gdb_stdlog
,
3004 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3006 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3007 target_pid_to_str (lp
->ptid
));
3009 gdb_assert (lp
->resumed
);
3011 /* Discard the event. */
3016 /* Make sure we don't report a SIGINT that we have already displayed
3017 for another thread. */
3018 if (lp
->ignore_sigint
3019 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3021 if (debug_linux_nat
)
3022 fprintf_unfiltered (gdb_stdlog
,
3023 "LLW: Delayed SIGINT caught for %s.\n",
3024 target_pid_to_str (lp
->ptid
));
3026 /* This is a delayed SIGINT. */
3027 lp
->ignore_sigint
= 0;
3029 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3030 if (debug_linux_nat
)
3031 fprintf_unfiltered (gdb_stdlog
,
3032 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3034 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3035 target_pid_to_str (lp
->ptid
));
3036 gdb_assert (lp
->resumed
);
3038 /* Discard the event. */
3042 /* Don't report signals that GDB isn't interested in, such as
3043 signals that are neither printed nor stopped upon. Stopping all
3044 threads can be a bit time-consuming so if we want decent
3045 performance with heavily multi-threaded programs, especially when
3046 they're using a high frequency timer, we'd better avoid it if we
3048 if (WIFSTOPPED (status
))
3050 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3054 /* Only do the below in all-stop, as we currently use SIGSTOP
3055 to implement target_stop (see linux_nat_stop) in
3057 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3059 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3060 forwarded to the entire process group, that is, all LWPs
3061 will receive it - unless they're using CLONE_THREAD to
3062 share signals. Since we only want to report it once, we
3063 mark it as ignored for all LWPs except this one. */
3064 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
3065 set_ignore_sigint
, NULL
);
3066 lp
->ignore_sigint
= 0;
3069 maybe_clear_ignore_sigint (lp
);
3072 /* When using hardware single-step, we need to report every signal.
3073 Otherwise, signals in pass_mask may be short-circuited
3074 except signals that might be caused by a breakpoint. */
3076 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
))
3077 && !linux_wstatus_maybe_breakpoint (status
))
3079 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3080 if (debug_linux_nat
)
3081 fprintf_unfiltered (gdb_stdlog
,
3082 "LLW: %s %s, %s (preempt 'handle')\n",
3084 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3085 target_pid_to_str (lp
->ptid
),
3086 (signo
!= GDB_SIGNAL_0
3087 ? strsignal (gdb_signal_to_host (signo
))
3093 /* An interesting event. */
3095 lp
->status
= status
;
3100 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3101 their exits until all other threads in the group have exited. */
3104 check_zombie_leaders (void)
3106 struct inferior
*inf
;
3110 struct lwp_info
*leader_lp
;
3115 leader_lp
= find_lwp_pid (pid_to_ptid (inf
->pid
));
3116 if (leader_lp
!= NULL
3117 /* Check if there are other threads in the group, as we may
3118 have raced with the inferior simply exiting. */
3119 && num_lwps (inf
->pid
) > 1
3120 && linux_proc_pid_is_zombie (inf
->pid
))
3122 if (debug_linux_nat
)
3123 fprintf_unfiltered (gdb_stdlog
,
3124 "CZL: Thread group leader %d zombie "
3125 "(it exited, or another thread execd).\n",
3128 /* A leader zombie can mean one of two things:
3130 - It exited, and there's an exit status pending
3131 available, or only the leader exited (not the whole
3132 program). In the latter case, we can't waitpid the
3133 leader's exit status until all other threads are gone.
3135 - There are 3 or more threads in the group, and a thread
3136 other than the leader exec'd. On an exec, the Linux
3137 kernel destroys all other threads (except the execing
3138 one) in the thread group, and resets the execing thread's
3139 tid to the tgid. No exit notification is sent for the
3140 execing thread -- from the ptracer's perspective, it
3141 appears as though the execing thread just vanishes.
3142 Until we reap all other threads except the leader and the
3143 execing thread, the leader will be zombie, and the
3144 execing thread will be in `D (disc sleep)'. As soon as
3145 all other threads are reaped, the execing thread changes
3146 it's tid to the tgid, and the previous (zombie) leader
3147 vanishes, giving place to the "new" leader. We could try
3148 distinguishing the exit and exec cases, by waiting once
3149 more, and seeing if something comes out, but it doesn't
3150 sound useful. The previous leader _does_ go away, and
3151 we'll re-add the new one once we see the exec event
3152 (which is just the same as what would happen if the
3153 previous leader did exit voluntarily before some other
3156 if (debug_linux_nat
)
3157 fprintf_unfiltered (gdb_stdlog
,
3158 "CZL: Thread group leader %d vanished.\n",
3160 exit_lwp (leader_lp
);
3166 linux_nat_wait_1 (struct target_ops
*ops
,
3167 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3171 enum resume_kind last_resume_kind
;
3172 struct lwp_info
*lp
;
3175 if (debug_linux_nat
)
3176 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3178 /* The first time we get here after starting a new inferior, we may
3179 not have added it to the LWP list yet - this is the earliest
3180 moment at which we know its PID. */
3181 if (ptid_is_pid (inferior_ptid
))
3183 /* Upgrade the main thread's ptid. */
3184 thread_change_ptid (inferior_ptid
,
3185 ptid_build (ptid_get_pid (inferior_ptid
),
3186 ptid_get_pid (inferior_ptid
), 0));
3188 lp
= add_initial_lwp (inferior_ptid
);
3192 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3193 block_child_signals (&prev_mask
);
3195 /* First check if there is a LWP with a wait status pending. */
3196 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3199 if (debug_linux_nat
)
3200 fprintf_unfiltered (gdb_stdlog
,
3201 "LLW: Using pending wait status %s for %s.\n",
3202 status_to_str (lp
->status
),
3203 target_pid_to_str (lp
->ptid
));
3206 if (!target_is_async_p ())
3208 /* Causes SIGINT to be passed on to the attached process. */
3212 /* But if we don't find a pending event, we'll have to wait. Always
3213 pull all events out of the kernel. We'll randomly select an
3214 event LWP out of all that have events, to prevent starvation. */
3220 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3223 - If the thread group leader exits while other threads in the
3224 thread group still exist, waitpid(TGID, ...) hangs. That
3225 waitpid won't return an exit status until the other threads
3226 in the group are reapped.
3228 - When a non-leader thread execs, that thread just vanishes
3229 without reporting an exit (so we'd hang if we waited for it
3230 explicitly in that case). The exec event is reported to
3234 lwpid
= my_waitpid (-1, &status
, __WCLONE
| WNOHANG
);
3235 if (lwpid
== 0 || (lwpid
== -1 && errno
== ECHILD
))
3236 lwpid
= my_waitpid (-1, &status
, WNOHANG
);
3238 if (debug_linux_nat
)
3239 fprintf_unfiltered (gdb_stdlog
,
3240 "LNW: waitpid(-1, ...) returned %d, %s\n",
3241 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3245 if (debug_linux_nat
)
3247 fprintf_unfiltered (gdb_stdlog
,
3248 "LLW: waitpid %ld received %s\n",
3249 (long) lwpid
, status_to_str (status
));
3252 linux_nat_filter_event (lwpid
, status
);
3253 /* Retry until nothing comes out of waitpid. A single
3254 SIGCHLD can indicate more than one child stopped. */
3258 /* Now that we've pulled all events out of the kernel, resume
3259 LWPs that don't have an interesting event to report. */
3260 iterate_over_lwps (minus_one_ptid
,
3261 resume_stopped_resumed_lwps
, &minus_one_ptid
);
3263 /* ... and find an LWP with a status to report to the core, if
3265 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3269 /* Check for zombie thread group leaders. Those can't be reaped
3270 until all other threads in the thread group are. */
3271 check_zombie_leaders ();
3273 /* If there are no resumed children left, bail. We'd be stuck
3274 forever in the sigsuspend call below otherwise. */
3275 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3277 if (debug_linux_nat
)
3278 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3280 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3282 if (!target_is_async_p ())
3283 clear_sigint_trap ();
3285 restore_child_signals_mask (&prev_mask
);
3286 return minus_one_ptid
;
3289 /* No interesting event to report to the core. */
3291 if (target_options
& TARGET_WNOHANG
)
3293 if (debug_linux_nat
)
3294 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3296 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3297 restore_child_signals_mask (&prev_mask
);
3298 return minus_one_ptid
;
3301 /* We shouldn't end up here unless we want to try again. */
3302 gdb_assert (lp
== NULL
);
3304 /* Block until we get an event reported with SIGCHLD. */
3305 if (debug_linux_nat
)
3306 fprintf_unfiltered (gdb_stdlog
, "LNW: about to sigsuspend\n");
3307 sigsuspend (&suspend_mask
);
3310 if (!target_is_async_p ())
3311 clear_sigint_trap ();
3315 status
= lp
->status
;
3320 /* Now stop all other LWP's ... */
3321 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3323 /* ... and wait until all of them have reported back that
3324 they're no longer running. */
3325 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3328 /* If we're not waiting for a specific LWP, choose an event LWP from
3329 among those that have had events. Giving equal priority to all
3330 LWPs that have had events helps prevent starvation. */
3331 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3332 select_event_lwp (ptid
, &lp
, &status
);
3334 gdb_assert (lp
!= NULL
);
3336 /* Now that we've selected our final event LWP, un-adjust its PC if
3337 it was a software breakpoint. */
3338 if (lp
->stop_reason
== LWP_STOPPED_BY_SW_BREAKPOINT
)
3340 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3341 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3342 int decr_pc
= target_decr_pc_after_break (gdbarch
);
3348 pc
= regcache_read_pc (regcache
);
3349 regcache_write_pc (regcache
, pc
+ decr_pc
);
3353 /* We'll need this to determine whether to report a SIGSTOP as
3354 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3356 last_resume_kind
= lp
->last_resume_kind
;
3360 /* In all-stop, from the core's perspective, all LWPs are now
3361 stopped until a new resume action is sent over. */
3362 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3366 resume_clear_callback (lp
, NULL
);
3369 if (linux_nat_status_is_event (status
))
3371 if (debug_linux_nat
)
3372 fprintf_unfiltered (gdb_stdlog
,
3373 "LLW: trap ptid is %s.\n",
3374 target_pid_to_str (lp
->ptid
));
3377 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3379 *ourstatus
= lp
->waitstatus
;
3380 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3383 store_waitstatus (ourstatus
, status
);
3385 if (debug_linux_nat
)
3386 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3388 restore_child_signals_mask (&prev_mask
);
3390 if (last_resume_kind
== resume_stop
3391 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3392 && WSTOPSIG (status
) == SIGSTOP
)
3394 /* A thread that has been requested to stop by GDB with
3395 target_stop, and it stopped cleanly, so report as SIG0. The
3396 use of SIGSTOP is an implementation detail. */
3397 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3400 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3401 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3404 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3409 /* Resume LWPs that are currently stopped without any pending status
3410 to report, but are resumed from the core's perspective. */
3413 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3415 ptid_t
*wait_ptid_p
= data
;
3419 && !lwp_status_pending_p (lp
))
3421 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3422 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3423 CORE_ADDR pc
= regcache_read_pc (regcache
);
3425 /* Don't bother if there's a breakpoint at PC that we'd hit
3426 immediately, and we're not waiting for this LWP. */
3427 if (!ptid_match (lp
->ptid
, *wait_ptid_p
))
3429 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
3433 if (debug_linux_nat
)
3434 fprintf_unfiltered (gdb_stdlog
,
3435 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3436 target_pid_to_str (lp
->ptid
),
3437 paddress (gdbarch
, pc
),
3440 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3447 linux_nat_wait (struct target_ops
*ops
,
3448 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3453 if (debug_linux_nat
)
3455 char *options_string
;
3457 options_string
= target_options_to_string (target_options
);
3458 fprintf_unfiltered (gdb_stdlog
,
3459 "linux_nat_wait: [%s], [%s]\n",
3460 target_pid_to_str (ptid
),
3462 xfree (options_string
);
3465 /* Flush the async file first. */
3466 if (target_is_async_p ())
3467 async_file_flush ();
3469 /* Resume LWPs that are currently stopped without any pending status
3470 to report, but are resumed from the core's perspective. LWPs get
3471 in this state if we find them stopping at a time we're not
3472 interested in reporting the event (target_wait on a
3473 specific_process, for example, see linux_nat_wait_1), and
3474 meanwhile the event became uninteresting. Don't bother resuming
3475 LWPs we're not going to wait for if they'd stop immediately. */
3477 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3479 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
3481 /* If we requested any event, and something came out, assume there
3482 may be more. If we requested a specific lwp or process, also
3483 assume there may be more. */
3484 if (target_is_async_p ()
3485 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3486 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3487 || !ptid_equal (ptid
, minus_one_ptid
)))
3494 kill_callback (struct lwp_info
*lp
, void *data
)
3496 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3499 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGKILL
);
3500 if (debug_linux_nat
)
3502 int save_errno
= errno
;
3504 fprintf_unfiltered (gdb_stdlog
,
3505 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3506 target_pid_to_str (lp
->ptid
),
3507 save_errno
? safe_strerror (save_errno
) : "OK");
3510 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3513 ptrace (PTRACE_KILL
, ptid_get_lwp (lp
->ptid
), 0, 0);
3514 if (debug_linux_nat
)
3516 int save_errno
= errno
;
3518 fprintf_unfiltered (gdb_stdlog
,
3519 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3520 target_pid_to_str (lp
->ptid
),
3521 save_errno
? safe_strerror (save_errno
) : "OK");
3528 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3532 /* We must make sure that there are no pending events (delayed
3533 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3534 program doesn't interfere with any following debugging session. */
3536 /* For cloned processes we must check both with __WCLONE and
3537 without, since the exit status of a cloned process isn't reported
3543 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, __WCLONE
);
3544 if (pid
!= (pid_t
) -1)
3546 if (debug_linux_nat
)
3547 fprintf_unfiltered (gdb_stdlog
,
3548 "KWC: wait %s received unknown.\n",
3549 target_pid_to_str (lp
->ptid
));
3550 /* The Linux kernel sometimes fails to kill a thread
3551 completely after PTRACE_KILL; that goes from the stop
3552 point in do_fork out to the one in
3553 get_signal_to_deliever and waits again. So kill it
3555 kill_callback (lp
, NULL
);
3558 while (pid
== ptid_get_lwp (lp
->ptid
));
3560 gdb_assert (pid
== -1 && errno
== ECHILD
);
3565 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, 0);
3566 if (pid
!= (pid_t
) -1)
3568 if (debug_linux_nat
)
3569 fprintf_unfiltered (gdb_stdlog
,
3570 "KWC: wait %s received unk.\n",
3571 target_pid_to_str (lp
->ptid
));
3572 /* See the call to kill_callback above. */
3573 kill_callback (lp
, NULL
);
3576 while (pid
== ptid_get_lwp (lp
->ptid
));
3578 gdb_assert (pid
== -1 && errno
== ECHILD
);
3583 linux_nat_kill (struct target_ops
*ops
)
3585 struct target_waitstatus last
;
3589 /* If we're stopped while forking and we haven't followed yet,
3590 kill the other task. We need to do this first because the
3591 parent will be sleeping if this is a vfork. */
3593 get_last_target_status (&last_ptid
, &last
);
3595 if (last
.kind
== TARGET_WAITKIND_FORKED
3596 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3598 ptrace (PT_KILL
, ptid_get_pid (last
.value
.related_pid
), 0, 0);
3601 /* Let the arch-specific native code know this process is
3603 linux_nat_forget_process (ptid_get_pid (last
.value
.related_pid
));
3606 if (forks_exist_p ())
3607 linux_fork_killall ();
3610 ptid_t ptid
= pid_to_ptid (ptid_get_pid (inferior_ptid
));
3612 /* Stop all threads before killing them, since ptrace requires
3613 that the thread is stopped to sucessfully PTRACE_KILL. */
3614 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3615 /* ... and wait until all of them have reported back that
3616 they're no longer running. */
3617 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3619 /* Kill all LWP's ... */
3620 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3622 /* ... and wait until we've flushed all events. */
3623 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3626 target_mourn_inferior ();
3630 linux_nat_mourn_inferior (struct target_ops
*ops
)
3632 int pid
= ptid_get_pid (inferior_ptid
);
3634 purge_lwp_list (pid
);
3636 if (! forks_exist_p ())
3637 /* Normal case, no other forks available. */
3638 linux_ops
->to_mourn_inferior (ops
);
3640 /* Multi-fork case. The current inferior_ptid has exited, but
3641 there are other viable forks to debug. Delete the exiting
3642 one and context-switch to the first available. */
3643 linux_fork_mourn_inferior ();
3645 /* Let the arch-specific native code know this process is gone. */
3646 linux_nat_forget_process (pid
);
3649 /* Convert a native/host siginfo object, into/from the siginfo in the
3650 layout of the inferiors' architecture. */
3653 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3657 if (linux_nat_siginfo_fixup
!= NULL
)
3658 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3660 /* If there was no callback, or the callback didn't do anything,
3661 then just do a straight memcpy. */
3665 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3667 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3671 static enum target_xfer_status
3672 linux_xfer_siginfo (struct target_ops
*ops
, enum target_object object
,
3673 const char *annex
, gdb_byte
*readbuf
,
3674 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3675 ULONGEST
*xfered_len
)
3679 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3681 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3682 gdb_assert (readbuf
|| writebuf
);
3684 pid
= ptid_get_lwp (inferior_ptid
);
3686 pid
= ptid_get_pid (inferior_ptid
);
3688 if (offset
> sizeof (siginfo
))
3689 return TARGET_XFER_E_IO
;
3692 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3694 return TARGET_XFER_E_IO
;
3696 /* When GDB is built as a 64-bit application, ptrace writes into
3697 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3698 inferior with a 64-bit GDB should look the same as debugging it
3699 with a 32-bit GDB, we need to convert it. GDB core always sees
3700 the converted layout, so any read/write will have to be done
3702 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3704 if (offset
+ len
> sizeof (siginfo
))
3705 len
= sizeof (siginfo
) - offset
;
3707 if (readbuf
!= NULL
)
3708 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3711 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3713 /* Convert back to ptrace layout before flushing it out. */
3714 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3717 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3719 return TARGET_XFER_E_IO
;
3723 return TARGET_XFER_OK
;
3726 static enum target_xfer_status
3727 linux_nat_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3728 const char *annex
, gdb_byte
*readbuf
,
3729 const gdb_byte
*writebuf
,
3730 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3732 struct cleanup
*old_chain
;
3733 enum target_xfer_status xfer
;
3735 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3736 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3737 offset
, len
, xfered_len
);
3739 /* The target is connected but no live inferior is selected. Pass
3740 this request down to a lower stratum (e.g., the executable
3742 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3743 return TARGET_XFER_EOF
;
3745 old_chain
= save_inferior_ptid ();
3747 if (ptid_lwp_p (inferior_ptid
))
3748 inferior_ptid
= pid_to_ptid (ptid_get_lwp (inferior_ptid
));
3750 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3751 offset
, len
, xfered_len
);
3753 do_cleanups (old_chain
);
3758 linux_thread_alive (ptid_t ptid
)
3762 gdb_assert (ptid_lwp_p (ptid
));
3764 /* Send signal 0 instead of anything ptrace, because ptracing a
3765 running thread errors out claiming that the thread doesn't
3767 err
= kill_lwp (ptid_get_lwp (ptid
), 0);
3769 if (debug_linux_nat
)
3770 fprintf_unfiltered (gdb_stdlog
,
3771 "LLTA: KILL(SIG0) %s (%s)\n",
3772 target_pid_to_str (ptid
),
3773 err
? safe_strerror (tmp_errno
) : "OK");
3782 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3784 return linux_thread_alive (ptid
);
3788 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3790 static char buf
[64];
3792 if (ptid_lwp_p (ptid
)
3793 && (ptid_get_pid (ptid
) != ptid_get_lwp (ptid
)
3794 || num_lwps (ptid_get_pid (ptid
)) > 1))
3796 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid_get_lwp (ptid
));
3800 return normal_pid_to_str (ptid
);
3804 linux_nat_thread_name (struct target_ops
*self
, struct thread_info
*thr
)
3806 int pid
= ptid_get_pid (thr
->ptid
);
3807 long lwp
= ptid_get_lwp (thr
->ptid
);
3808 #define FORMAT "/proc/%d/task/%ld/comm"
3809 char buf
[sizeof (FORMAT
) + 30];
3811 char *result
= NULL
;
3813 snprintf (buf
, sizeof (buf
), FORMAT
, pid
, lwp
);
3814 comm_file
= gdb_fopen_cloexec (buf
, "r");
3817 /* Not exported by the kernel, so we define it here. */
3819 static char line
[COMM_LEN
+ 1];
3821 if (fgets (line
, sizeof (line
), comm_file
))
3823 char *nl
= strchr (line
, '\n');
3840 /* Accepts an integer PID; Returns a string representing a file that
3841 can be opened to get the symbols for the child process. */
3844 linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
)
3846 static char buf
[PATH_MAX
];
3847 char name
[PATH_MAX
];
3849 xsnprintf (name
, PATH_MAX
, "/proc/%d/exe", pid
);
3850 memset (buf
, 0, PATH_MAX
);
3851 if (readlink (name
, buf
, PATH_MAX
- 1) <= 0)
3857 /* Implement the to_xfer_partial interface for memory reads using the /proc
3858 filesystem. Because we can use a single read() call for /proc, this
3859 can be much more efficient than banging away at PTRACE_PEEKTEXT,
3860 but it doesn't support writes. */
3862 static enum target_xfer_status
3863 linux_proc_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3864 const char *annex
, gdb_byte
*readbuf
,
3865 const gdb_byte
*writebuf
,
3866 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3872 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
3875 /* Don't bother for one word. */
3876 if (len
< 3 * sizeof (long))
3877 return TARGET_XFER_EOF
;
3879 /* We could keep this file open and cache it - possibly one per
3880 thread. That requires some juggling, but is even faster. */
3881 xsnprintf (filename
, sizeof filename
, "/proc/%d/mem",
3882 ptid_get_pid (inferior_ptid
));
3883 fd
= gdb_open_cloexec (filename
, O_RDONLY
| O_LARGEFILE
, 0);
3885 return TARGET_XFER_EOF
;
3887 /* If pread64 is available, use it. It's faster if the kernel
3888 supports it (only one syscall), and it's 64-bit safe even on
3889 32-bit platforms (for instance, SPARC debugging a SPARC64
3892 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
3894 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
3903 return TARGET_XFER_EOF
;
3907 return TARGET_XFER_OK
;
3912 /* Enumerate spufs IDs for process PID. */
3914 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
3916 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
3918 LONGEST written
= 0;
3921 struct dirent
*entry
;
3923 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
3924 dir
= opendir (path
);
3929 while ((entry
= readdir (dir
)) != NULL
)
3935 fd
= atoi (entry
->d_name
);
3939 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
3940 if (stat (path
, &st
) != 0)
3942 if (!S_ISDIR (st
.st_mode
))
3945 if (statfs (path
, &stfs
) != 0)
3947 if (stfs
.f_type
!= SPUFS_MAGIC
)
3950 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
3952 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
3962 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
3963 object type, using the /proc file system. */
3965 static enum target_xfer_status
3966 linux_proc_xfer_spu (struct target_ops
*ops
, enum target_object object
,
3967 const char *annex
, gdb_byte
*readbuf
,
3968 const gdb_byte
*writebuf
,
3969 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3974 int pid
= ptid_get_pid (inferior_ptid
);
3979 return TARGET_XFER_E_IO
;
3982 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
3985 return TARGET_XFER_E_IO
;
3987 return TARGET_XFER_EOF
;
3990 *xfered_len
= (ULONGEST
) l
;
3991 return TARGET_XFER_OK
;
3996 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
3997 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
3999 return TARGET_XFER_E_IO
;
4002 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4005 return TARGET_XFER_EOF
;
4009 ret
= write (fd
, writebuf
, (size_t) len
);
4011 ret
= read (fd
, readbuf
, (size_t) len
);
4016 return TARGET_XFER_E_IO
;
4018 return TARGET_XFER_EOF
;
4021 *xfered_len
= (ULONGEST
) ret
;
4022 return TARGET_XFER_OK
;
4027 /* Parse LINE as a signal set and add its set bits to SIGS. */
4030 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4032 int len
= strlen (line
) - 1;
4036 if (line
[len
] != '\n')
4037 error (_("Could not parse signal set: %s"), line
);
4045 if (*p
>= '0' && *p
<= '9')
4047 else if (*p
>= 'a' && *p
<= 'f')
4048 digit
= *p
- 'a' + 10;
4050 error (_("Could not parse signal set: %s"), line
);
4055 sigaddset (sigs
, signum
+ 1);
4057 sigaddset (sigs
, signum
+ 2);
4059 sigaddset (sigs
, signum
+ 3);
4061 sigaddset (sigs
, signum
+ 4);
4067 /* Find process PID's pending signals from /proc/pid/status and set
4071 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4072 sigset_t
*blocked
, sigset_t
*ignored
)
4075 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4076 struct cleanup
*cleanup
;
4078 sigemptyset (pending
);
4079 sigemptyset (blocked
);
4080 sigemptyset (ignored
);
4081 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4082 procfile
= gdb_fopen_cloexec (fname
, "r");
4083 if (procfile
== NULL
)
4084 error (_("Could not open %s"), fname
);
4085 cleanup
= make_cleanup_fclose (procfile
);
4087 while (fgets (buffer
, PATH_MAX
, procfile
) != NULL
)
4089 /* Normal queued signals are on the SigPnd line in the status
4090 file. However, 2.6 kernels also have a "shared" pending
4091 queue for delivering signals to a thread group, so check for
4094 Unfortunately some Red Hat kernels include the shared pending
4095 queue but not the ShdPnd status field. */
4097 if (strncmp (buffer
, "SigPnd:\t", 8) == 0)
4098 add_line_to_sigset (buffer
+ 8, pending
);
4099 else if (strncmp (buffer
, "ShdPnd:\t", 8) == 0)
4100 add_line_to_sigset (buffer
+ 8, pending
);
4101 else if (strncmp (buffer
, "SigBlk:\t", 8) == 0)
4102 add_line_to_sigset (buffer
+ 8, blocked
);
4103 else if (strncmp (buffer
, "SigIgn:\t", 8) == 0)
4104 add_line_to_sigset (buffer
+ 8, ignored
);
4107 do_cleanups (cleanup
);
4110 static enum target_xfer_status
4111 linux_nat_xfer_osdata (struct target_ops
*ops
, enum target_object object
,
4112 const char *annex
, gdb_byte
*readbuf
,
4113 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4114 ULONGEST
*xfered_len
)
4116 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4118 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4119 if (*xfered_len
== 0)
4120 return TARGET_XFER_EOF
;
4122 return TARGET_XFER_OK
;
4125 static enum target_xfer_status
4126 linux_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4127 const char *annex
, gdb_byte
*readbuf
,
4128 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4129 ULONGEST
*xfered_len
)
4131 enum target_xfer_status xfer
;
4133 if (object
== TARGET_OBJECT_AUXV
)
4134 return memory_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4135 offset
, len
, xfered_len
);
4137 if (object
== TARGET_OBJECT_OSDATA
)
4138 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4139 offset
, len
, xfered_len
);
4141 if (object
== TARGET_OBJECT_SPU
)
4142 return linux_proc_xfer_spu (ops
, object
, annex
, readbuf
, writebuf
,
4143 offset
, len
, xfered_len
);
4145 /* GDB calculates all the addresses in possibly larget width of the address.
4146 Address width needs to be masked before its final use - either by
4147 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4149 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4151 if (object
== TARGET_OBJECT_MEMORY
)
4153 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
4155 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
4156 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
4159 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4160 offset
, len
, xfered_len
);
4161 if (xfer
!= TARGET_XFER_EOF
)
4164 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4165 offset
, len
, xfered_len
);
4169 cleanup_target_stop (void *arg
)
4171 ptid_t
*ptid
= (ptid_t
*) arg
;
4173 gdb_assert (arg
!= NULL
);
4176 target_resume (*ptid
, 0, GDB_SIGNAL_0
);
4179 static VEC(static_tracepoint_marker_p
) *
4180 linux_child_static_tracepoint_markers_by_strid (struct target_ops
*self
,
4183 char s
[IPA_CMD_BUF_SIZE
];
4184 struct cleanup
*old_chain
;
4185 int pid
= ptid_get_pid (inferior_ptid
);
4186 VEC(static_tracepoint_marker_p
) *markers
= NULL
;
4187 struct static_tracepoint_marker
*marker
= NULL
;
4189 ptid_t ptid
= ptid_build (pid
, 0, 0);
4194 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4195 s
[sizeof ("qTfSTM")] = 0;
4197 agent_run_command (pid
, s
, strlen (s
) + 1);
4199 old_chain
= make_cleanup (free_current_marker
, &marker
);
4200 make_cleanup (cleanup_target_stop
, &ptid
);
4205 marker
= XCNEW (struct static_tracepoint_marker
);
4209 parse_static_tracepoint_marker_definition (p
, &p
, marker
);
4211 if (strid
== NULL
|| strcmp (strid
, marker
->str_id
) == 0)
4213 VEC_safe_push (static_tracepoint_marker_p
,
4219 release_static_tracepoint_marker (marker
);
4220 memset (marker
, 0, sizeof (*marker
));
4223 while (*p
++ == ','); /* comma-separated list */
4225 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4226 s
[sizeof ("qTsSTM")] = 0;
4227 agent_run_command (pid
, s
, strlen (s
) + 1);
4231 do_cleanups (old_chain
);
4236 /* Create a prototype generic GNU/Linux target. The client can override
4237 it with local methods. */
4240 linux_target_install_ops (struct target_ops
*t
)
4242 t
->to_insert_fork_catchpoint
= linux_child_insert_fork_catchpoint
;
4243 t
->to_remove_fork_catchpoint
= linux_child_remove_fork_catchpoint
;
4244 t
->to_insert_vfork_catchpoint
= linux_child_insert_vfork_catchpoint
;
4245 t
->to_remove_vfork_catchpoint
= linux_child_remove_vfork_catchpoint
;
4246 t
->to_insert_exec_catchpoint
= linux_child_insert_exec_catchpoint
;
4247 t
->to_remove_exec_catchpoint
= linux_child_remove_exec_catchpoint
;
4248 t
->to_set_syscall_catchpoint
= linux_child_set_syscall_catchpoint
;
4249 t
->to_pid_to_exec_file
= linux_child_pid_to_exec_file
;
4250 t
->to_post_startup_inferior
= linux_child_post_startup_inferior
;
4251 t
->to_post_attach
= linux_child_post_attach
;
4252 t
->to_follow_fork
= linux_child_follow_fork
;
4254 super_xfer_partial
= t
->to_xfer_partial
;
4255 t
->to_xfer_partial
= linux_xfer_partial
;
4257 t
->to_static_tracepoint_markers_by_strid
4258 = linux_child_static_tracepoint_markers_by_strid
;
4264 struct target_ops
*t
;
4266 t
= inf_ptrace_target ();
4267 linux_target_install_ops (t
);
4273 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4275 struct target_ops
*t
;
4277 t
= inf_ptrace_trad_target (register_u_offset
);
4278 linux_target_install_ops (t
);
4283 /* target_is_async_p implementation. */
4286 linux_nat_is_async_p (struct target_ops
*ops
)
4288 return linux_is_async_p ();
4291 /* target_can_async_p implementation. */
4294 linux_nat_can_async_p (struct target_ops
*ops
)
4296 /* NOTE: palves 2008-03-21: We're only async when the user requests
4297 it explicitly with the "set target-async" command.
4298 Someday, linux will always be async. */
4299 return target_async_permitted
;
4303 linux_nat_supports_non_stop (struct target_ops
*self
)
4308 /* True if we want to support multi-process. To be removed when GDB
4309 supports multi-exec. */
4311 int linux_multi_process
= 1;
4314 linux_nat_supports_multi_process (struct target_ops
*self
)
4316 return linux_multi_process
;
4320 linux_nat_supports_disable_randomization (struct target_ops
*self
)
4322 #ifdef HAVE_PERSONALITY
4329 static int async_terminal_is_ours
= 1;
4331 /* target_terminal_inferior implementation.
4333 This is a wrapper around child_terminal_inferior to add async support. */
4336 linux_nat_terminal_inferior (struct target_ops
*self
)
4338 /* Like target_terminal_inferior, use target_can_async_p, not
4339 target_is_async_p, since at this point the target is not async
4340 yet. If it can async, then we know it will become async prior to
4342 if (!target_can_async_p ())
4344 /* Async mode is disabled. */
4345 child_terminal_inferior (self
);
4349 child_terminal_inferior (self
);
4351 /* Calls to target_terminal_*() are meant to be idempotent. */
4352 if (!async_terminal_is_ours
)
4355 delete_file_handler (input_fd
);
4356 async_terminal_is_ours
= 0;
4360 /* target_terminal_ours implementation.
4362 This is a wrapper around child_terminal_ours to add async support (and
4363 implement the target_terminal_ours vs target_terminal_ours_for_output
4364 distinction). child_terminal_ours is currently no different than
4365 child_terminal_ours_for_output.
4366 We leave target_terminal_ours_for_output alone, leaving it to
4367 child_terminal_ours_for_output. */
4370 linux_nat_terminal_ours (struct target_ops
*self
)
4372 /* GDB should never give the terminal to the inferior if the
4373 inferior is running in the background (run&, continue&, etc.),
4374 but claiming it sure should. */
4375 child_terminal_ours (self
);
4377 if (async_terminal_is_ours
)
4380 clear_sigint_trap ();
4381 add_file_handler (input_fd
, stdin_event_handler
, 0);
4382 async_terminal_is_ours
= 1;
4385 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4387 static void *async_client_context
;
4389 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4390 so we notice when any child changes state, and notify the
4391 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4392 above to wait for the arrival of a SIGCHLD. */
4395 sigchld_handler (int signo
)
4397 int old_errno
= errno
;
4399 if (debug_linux_nat
)
4400 ui_file_write_async_safe (gdb_stdlog
,
4401 "sigchld\n", sizeof ("sigchld\n") - 1);
4403 if (signo
== SIGCHLD
4404 && linux_nat_event_pipe
[0] != -1)
4405 async_file_mark (); /* Let the event loop know that there are
4406 events to handle. */
4411 /* Callback registered with the target events file descriptor. */
4414 handle_target_event (int error
, gdb_client_data client_data
)
4416 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4419 /* Create/destroy the target events pipe. Returns previous state. */
4422 linux_async_pipe (int enable
)
4424 int previous
= linux_is_async_p ();
4426 if (previous
!= enable
)
4430 /* Block child signals while we create/destroy the pipe, as
4431 their handler writes to it. */
4432 block_child_signals (&prev_mask
);
4436 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4437 internal_error (__FILE__
, __LINE__
,
4438 "creating event pipe failed.");
4440 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4441 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4445 close (linux_nat_event_pipe
[0]);
4446 close (linux_nat_event_pipe
[1]);
4447 linux_nat_event_pipe
[0] = -1;
4448 linux_nat_event_pipe
[1] = -1;
4451 restore_child_signals_mask (&prev_mask
);
4457 /* target_async implementation. */
4460 linux_nat_async (struct target_ops
*ops
,
4461 void (*callback
) (enum inferior_event_type event_type
,
4465 if (callback
!= NULL
)
4467 async_client_callback
= callback
;
4468 async_client_context
= context
;
4469 if (!linux_async_pipe (1))
4471 add_file_handler (linux_nat_event_pipe
[0],
4472 handle_target_event
, NULL
);
4473 /* There may be pending events to handle. Tell the event loop
4480 async_client_callback
= callback
;
4481 async_client_context
= context
;
4482 delete_file_handler (linux_nat_event_pipe
[0]);
4483 linux_async_pipe (0);
4488 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4492 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4496 if (debug_linux_nat
)
4497 fprintf_unfiltered (gdb_stdlog
,
4498 "LNSL: running -> suspending %s\n",
4499 target_pid_to_str (lwp
->ptid
));
4502 if (lwp
->last_resume_kind
== resume_stop
)
4504 if (debug_linux_nat
)
4505 fprintf_unfiltered (gdb_stdlog
,
4506 "linux-nat: already stopping LWP %ld at "
4508 ptid_get_lwp (lwp
->ptid
));
4512 stop_callback (lwp
, NULL
);
4513 lwp
->last_resume_kind
= resume_stop
;
4517 /* Already known to be stopped; do nothing. */
4519 if (debug_linux_nat
)
4521 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4522 fprintf_unfiltered (gdb_stdlog
,
4523 "LNSL: already stopped/stop_requested %s\n",
4524 target_pid_to_str (lwp
->ptid
));
4526 fprintf_unfiltered (gdb_stdlog
,
4527 "LNSL: already stopped/no "
4528 "stop_requested yet %s\n",
4529 target_pid_to_str (lwp
->ptid
));
4536 linux_nat_stop (struct target_ops
*self
, ptid_t ptid
)
4539 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4541 linux_ops
->to_stop (linux_ops
, ptid
);
4545 linux_nat_close (struct target_ops
*self
)
4547 /* Unregister from the event loop. */
4548 if (linux_nat_is_async_p (self
))
4549 linux_nat_async (self
, NULL
, NULL
);
4551 if (linux_ops
->to_close
)
4552 linux_ops
->to_close (linux_ops
);
4557 /* When requests are passed down from the linux-nat layer to the
4558 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4559 used. The address space pointer is stored in the inferior object,
4560 but the common code that is passed such ptid can't tell whether
4561 lwpid is a "main" process id or not (it assumes so). We reverse
4562 look up the "main" process id from the lwp here. */
4564 static struct address_space
*
4565 linux_nat_thread_address_space (struct target_ops
*t
, ptid_t ptid
)
4567 struct lwp_info
*lwp
;
4568 struct inferior
*inf
;
4571 if (ptid_get_lwp (ptid
) == 0)
4573 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4575 lwp
= find_lwp_pid (ptid
);
4576 pid
= ptid_get_pid (lwp
->ptid
);
4580 /* A (pid,lwpid,0) ptid. */
4581 pid
= ptid_get_pid (ptid
);
4584 inf
= find_inferior_pid (pid
);
4585 gdb_assert (inf
!= NULL
);
4589 /* Return the cached value of the processor core for thread PTID. */
4592 linux_nat_core_of_thread (struct target_ops
*ops
, ptid_t ptid
)
4594 struct lwp_info
*info
= find_lwp_pid (ptid
);
4602 linux_nat_add_target (struct target_ops
*t
)
4604 /* Save the provided single-threaded target. We save this in a separate
4605 variable because another target we've inherited from (e.g. inf-ptrace)
4606 may have saved a pointer to T; we want to use it for the final
4607 process stratum target. */
4608 linux_ops_saved
= *t
;
4609 linux_ops
= &linux_ops_saved
;
4611 /* Override some methods for multithreading. */
4612 t
->to_create_inferior
= linux_nat_create_inferior
;
4613 t
->to_attach
= linux_nat_attach
;
4614 t
->to_detach
= linux_nat_detach
;
4615 t
->to_resume
= linux_nat_resume
;
4616 t
->to_wait
= linux_nat_wait
;
4617 t
->to_pass_signals
= linux_nat_pass_signals
;
4618 t
->to_xfer_partial
= linux_nat_xfer_partial
;
4619 t
->to_kill
= linux_nat_kill
;
4620 t
->to_mourn_inferior
= linux_nat_mourn_inferior
;
4621 t
->to_thread_alive
= linux_nat_thread_alive
;
4622 t
->to_pid_to_str
= linux_nat_pid_to_str
;
4623 t
->to_thread_name
= linux_nat_thread_name
;
4624 t
->to_has_thread_control
= tc_schedlock
;
4625 t
->to_thread_address_space
= linux_nat_thread_address_space
;
4626 t
->to_stopped_by_watchpoint
= linux_nat_stopped_by_watchpoint
;
4627 t
->to_stopped_data_address
= linux_nat_stopped_data_address
;
4629 t
->to_can_async_p
= linux_nat_can_async_p
;
4630 t
->to_is_async_p
= linux_nat_is_async_p
;
4631 t
->to_supports_non_stop
= linux_nat_supports_non_stop
;
4632 t
->to_async
= linux_nat_async
;
4633 t
->to_terminal_inferior
= linux_nat_terminal_inferior
;
4634 t
->to_terminal_ours
= linux_nat_terminal_ours
;
4636 super_close
= t
->to_close
;
4637 t
->to_close
= linux_nat_close
;
4639 /* Methods for non-stop support. */
4640 t
->to_stop
= linux_nat_stop
;
4642 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
4644 t
->to_supports_disable_randomization
4645 = linux_nat_supports_disable_randomization
;
4647 t
->to_core_of_thread
= linux_nat_core_of_thread
;
4649 /* We don't change the stratum; this target will sit at
4650 process_stratum and thread_db will set at thread_stratum. This
4651 is a little strange, since this is a multi-threaded-capable
4652 target, but we want to be on the stack below thread_db, and we
4653 also want to be used for single-threaded processes. */
4658 /* Register a method to call whenever a new thread is attached. */
4660 linux_nat_set_new_thread (struct target_ops
*t
,
4661 void (*new_thread
) (struct lwp_info
*))
4663 /* Save the pointer. We only support a single registered instance
4664 of the GNU/Linux native target, so we do not need to map this to
4666 linux_nat_new_thread
= new_thread
;
4669 /* See declaration in linux-nat.h. */
4672 linux_nat_set_new_fork (struct target_ops
*t
,
4673 linux_nat_new_fork_ftype
*new_fork
)
4675 /* Save the pointer. */
4676 linux_nat_new_fork
= new_fork
;
4679 /* See declaration in linux-nat.h. */
4682 linux_nat_set_forget_process (struct target_ops
*t
,
4683 linux_nat_forget_process_ftype
*fn
)
4685 /* Save the pointer. */
4686 linux_nat_forget_process_hook
= fn
;
4689 /* See declaration in linux-nat.h. */
4692 linux_nat_forget_process (pid_t pid
)
4694 if (linux_nat_forget_process_hook
!= NULL
)
4695 linux_nat_forget_process_hook (pid
);
4698 /* Register a method that converts a siginfo object between the layout
4699 that ptrace returns, and the layout in the architecture of the
4702 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4703 int (*siginfo_fixup
) (siginfo_t
*,
4707 /* Save the pointer. */
4708 linux_nat_siginfo_fixup
= siginfo_fixup
;
4711 /* Register a method to call prior to resuming a thread. */
4714 linux_nat_set_prepare_to_resume (struct target_ops
*t
,
4715 void (*prepare_to_resume
) (struct lwp_info
*))
4717 /* Save the pointer. */
4718 linux_nat_prepare_to_resume
= prepare_to_resume
;
4721 /* See linux-nat.h. */
4724 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4728 pid
= ptid_get_lwp (ptid
);
4730 pid
= ptid_get_pid (ptid
);
4733 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4736 memset (siginfo
, 0, sizeof (*siginfo
));
4742 /* Provide a prototype to silence -Wmissing-prototypes. */
4743 extern initialize_file_ftype _initialize_linux_nat
;
4746 _initialize_linux_nat (void)
4748 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4749 &debug_linux_nat
, _("\
4750 Set debugging of GNU/Linux lwp module."), _("\
4751 Show debugging of GNU/Linux lwp module."), _("\
4752 Enables printf debugging output."),
4754 show_debug_linux_nat
,
4755 &setdebuglist
, &showdebuglist
);
4757 /* Save this mask as the default. */
4758 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
4760 /* Install a SIGCHLD handler. */
4761 sigchld_action
.sa_handler
= sigchld_handler
;
4762 sigemptyset (&sigchld_action
.sa_mask
);
4763 sigchld_action
.sa_flags
= SA_RESTART
;
4765 /* Make it the default. */
4766 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4768 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4769 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4770 sigdelset (&suspend_mask
, SIGCHLD
);
4772 sigemptyset (&blocked_mask
);
4774 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
4775 support read-only process state. */
4776 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
4777 | PTRACE_O_TRACEVFORKDONE
4778 | PTRACE_O_TRACEVFORK
4779 | PTRACE_O_TRACEFORK
4780 | PTRACE_O_TRACEEXEC
);
4784 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4785 the GNU/Linux Threads library and therefore doesn't really belong
4788 /* Read variable NAME in the target and return its value if found.
4789 Otherwise return zero. It is assumed that the type of the variable
4793 get_signo (const char *name
)
4795 struct bound_minimal_symbol ms
;
4798 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
4799 if (ms
.minsym
== NULL
)
4802 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
4803 sizeof (signo
)) != 0)
4809 /* Return the set of signals used by the threads library in *SET. */
4812 lin_thread_get_thread_signals (sigset_t
*set
)
4814 struct sigaction action
;
4815 int restart
, cancel
;
4817 sigemptyset (&blocked_mask
);
4820 restart
= get_signo ("__pthread_sig_restart");
4821 cancel
= get_signo ("__pthread_sig_cancel");
4823 /* LinuxThreads normally uses the first two RT signals, but in some legacy
4824 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
4825 not provide any way for the debugger to query the signal numbers -
4826 fortunately they don't change! */
4829 restart
= __SIGRTMIN
;
4832 cancel
= __SIGRTMIN
+ 1;
4834 sigaddset (set
, restart
);
4835 sigaddset (set
, cancel
);
4837 /* The GNU/Linux Threads library makes terminating threads send a
4838 special "cancel" signal instead of SIGCHLD. Make sure we catch
4839 those (to prevent them from terminating GDB itself, which is
4840 likely to be their default action) and treat them the same way as
4843 action
.sa_handler
= sigchld_handler
;
4844 sigemptyset (&action
.sa_mask
);
4845 action
.sa_flags
= SA_RESTART
;
4846 sigaction (cancel
, &action
, NULL
);
4848 /* We block the "cancel" signal throughout this code ... */
4849 sigaddset (&blocked_mask
, cancel
);
4850 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
4852 /* ... except during a sigsuspend. */
4853 sigdelset (&suspend_mask
, cancel
);