1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2015 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
27 #ifdef HAVE_TKILL_SYSCALL
29 #include <sys/syscall.h>
31 #include <sys/ptrace.h>
32 #include "linux-nat.h"
33 #include "nat/linux-ptrace.h"
34 #include "nat/linux-procfs.h"
35 #include "nat/linux-personality.h"
36 #include "linux-fork.h"
37 #include "gdbthread.h"
41 #include "inf-child.h"
42 #include "inf-ptrace.h"
44 #include <sys/procfs.h> /* for elf_gregset etc. */
45 #include "elf-bfd.h" /* for elfcore_write_* */
46 #include "gregset.h" /* for gregset */
47 #include "gdbcore.h" /* for get_exec_file */
48 #include <ctype.h> /* for isdigit */
49 #include <sys/stat.h> /* for struct stat */
50 #include <fcntl.h> /* for O_RDONLY */
52 #include "event-loop.h"
53 #include "event-top.h"
55 #include <sys/types.h>
57 #include "xml-support.h"
60 #include "nat/linux-osdata.h"
61 #include "linux-tdep.h"
64 #include "tracepoint.h"
66 #include "target-descriptions.h"
67 #include "filestuff.h"
71 #define SPUFS_MAGIC 0x23c9b64e
74 /* This comment documents high-level logic of this file.
76 Waiting for events in sync mode
77 ===============================
79 When waiting for an event in a specific thread, we just use waitpid, passing
80 the specific pid, and not passing WNOHANG.
82 When waiting for an event in all threads, waitpid is not quite good. Prior to
83 version 2.4, Linux can either wait for event in main thread, or in secondary
84 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
85 miss an event. The solution is to use non-blocking waitpid, together with
86 sigsuspend. First, we use non-blocking waitpid to get an event in the main
87 process, if any. Second, we use non-blocking waitpid with the __WCLONED
88 flag to check for events in cloned processes. If nothing is found, we use
89 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
90 happened to a child process -- and SIGCHLD will be delivered both for events
91 in main debugged process and in cloned processes. As soon as we know there's
92 an event, we get back to calling nonblocking waitpid with and without
95 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
96 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
97 blocked, the signal becomes pending and sigsuspend immediately
98 notices it and returns.
100 Waiting for events in async mode
101 ================================
103 In async mode, GDB should always be ready to handle both user input
104 and target events, so neither blocking waitpid nor sigsuspend are
105 viable options. Instead, we should asynchronously notify the GDB main
106 event loop whenever there's an unprocessed event from the target. We
107 detect asynchronous target events by handling SIGCHLD signals. To
108 notify the event loop about target events, the self-pipe trick is used
109 --- a pipe is registered as waitable event source in the event loop,
110 the event loop select/poll's on the read end of this pipe (as well on
111 other event sources, e.g., stdin), and the SIGCHLD handler writes a
112 byte to this pipe. This is more portable than relying on
113 pselect/ppoll, since on kernels that lack those syscalls, libc
114 emulates them with select/poll+sigprocmask, and that is racy
115 (a.k.a. plain broken).
117 Obviously, if we fail to notify the event loop if there's a target
118 event, it's bad. OTOH, if we notify the event loop when there's no
119 event from the target, linux_nat_wait will detect that there's no real
120 event to report, and return event of type TARGET_WAITKIND_IGNORE.
121 This is mostly harmless, but it will waste time and is better avoided.
123 The main design point is that every time GDB is outside linux-nat.c,
124 we have a SIGCHLD handler installed that is called when something
125 happens to the target and notifies the GDB event loop. Whenever GDB
126 core decides to handle the event, and calls into linux-nat.c, we
127 process things as in sync mode, except that the we never block in
130 While processing an event, we may end up momentarily blocked in
131 waitpid calls. Those waitpid calls, while blocking, are guarantied to
132 return quickly. E.g., in all-stop mode, before reporting to the core
133 that an LWP hit a breakpoint, all LWPs are stopped by sending them
134 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
135 Note that this is different from blocking indefinitely waiting for the
136 next event --- here, we're already handling an event.
141 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
142 signal is not entirely significant; we just need for a signal to be delivered,
143 so that we can intercept it. SIGSTOP's advantage is that it can not be
144 blocked. A disadvantage is that it is not a real-time signal, so it can only
145 be queued once; we do not keep track of other sources of SIGSTOP.
147 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
148 use them, because they have special behavior when the signal is generated -
149 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
150 kills the entire thread group.
152 A delivered SIGSTOP would stop the entire thread group, not just the thread we
153 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
154 cancel it (by PTRACE_CONT without passing SIGSTOP).
156 We could use a real-time signal instead. This would solve those problems; we
157 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
158 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
159 generates it, and there are races with trying to find a signal that is not
163 #define O_LARGEFILE 0
166 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
167 the use of the multi-threaded target. */
168 static struct target_ops
*linux_ops
;
169 static struct target_ops linux_ops_saved
;
171 /* The method to call, if any, when a new thread is attached. */
172 static void (*linux_nat_new_thread
) (struct lwp_info
*);
174 /* The method to call, if any, when a new fork is attached. */
175 static linux_nat_new_fork_ftype
*linux_nat_new_fork
;
177 /* The method to call, if any, when a process is no longer
179 static linux_nat_forget_process_ftype
*linux_nat_forget_process_hook
;
181 /* Hook to call prior to resuming a thread. */
182 static void (*linux_nat_prepare_to_resume
) (struct lwp_info
*);
184 /* The method to call, if any, when the siginfo object needs to be
185 converted between the layout returned by ptrace, and the layout in
186 the architecture of the inferior. */
187 static int (*linux_nat_siginfo_fixup
) (siginfo_t
*,
191 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
192 Called by our to_xfer_partial. */
193 static target_xfer_partial_ftype
*super_xfer_partial
;
195 /* The saved to_close method, inherited from inf-ptrace.c.
196 Called by our to_close. */
197 static void (*super_close
) (struct target_ops
*);
199 static unsigned int debug_linux_nat
;
201 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
202 struct cmd_list_element
*c
, const char *value
)
204 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
208 struct simple_pid_list
212 struct simple_pid_list
*next
;
214 struct simple_pid_list
*stopped_pids
;
216 /* Async mode support. */
218 /* The read/write ends of the pipe registered as waitable file in the
220 static int linux_nat_event_pipe
[2] = { -1, -1 };
222 /* True if we're currently in async mode. */
223 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
225 /* Flush the event pipe. */
228 async_file_flush (void)
235 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
237 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
240 /* Put something (anything, doesn't matter what, or how much) in event
241 pipe, so that the select/poll in the event-loop realizes we have
242 something to process. */
245 async_file_mark (void)
249 /* It doesn't really matter what the pipe contains, as long we end
250 up with something in it. Might as well flush the previous
256 ret
= write (linux_nat_event_pipe
[1], "+", 1);
258 while (ret
== -1 && errno
== EINTR
);
260 /* Ignore EAGAIN. If the pipe is full, the event loop will already
261 be awakened anyway. */
264 static int kill_lwp (int lwpid
, int signo
);
266 static int stop_callback (struct lwp_info
*lp
, void *data
);
267 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
);
269 static void block_child_signals (sigset_t
*prev_mask
);
270 static void restore_child_signals_mask (sigset_t
*prev_mask
);
273 static struct lwp_info
*add_lwp (ptid_t ptid
);
274 static void purge_lwp_list (int pid
);
275 static void delete_lwp (ptid_t ptid
);
276 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
278 static int lwp_status_pending_p (struct lwp_info
*lp
);
280 static int check_stopped_by_breakpoint (struct lwp_info
*lp
);
281 static int sigtrap_is_event (int status
);
282 static int (*linux_nat_status_is_event
) (int status
) = sigtrap_is_event
;
285 /* Trivial list manipulation functions to keep track of a list of
286 new stopped processes. */
288 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
290 struct simple_pid_list
*new_pid
= xmalloc (sizeof (struct simple_pid_list
));
293 new_pid
->status
= status
;
294 new_pid
->next
= *listp
;
299 in_pid_list_p (struct simple_pid_list
*list
, int pid
)
301 struct simple_pid_list
*p
;
303 for (p
= list
; p
!= NULL
; p
= p
->next
)
310 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
312 struct simple_pid_list
**p
;
314 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
315 if ((*p
)->pid
== pid
)
317 struct simple_pid_list
*next
= (*p
)->next
;
319 *statusp
= (*p
)->status
;
327 /* Initialize ptrace warnings and check for supported ptrace
330 ATTACHED should be nonzero iff we attached to the inferior. */
333 linux_init_ptrace (pid_t pid
, int attached
)
335 linux_enable_event_reporting (pid
, attached
);
336 linux_ptrace_init_warnings ();
340 linux_child_post_attach (struct target_ops
*self
, int pid
)
342 linux_init_ptrace (pid
, 1);
346 linux_child_post_startup_inferior (struct target_ops
*self
, ptid_t ptid
)
348 linux_init_ptrace (ptid_get_pid (ptid
), 0);
351 /* Return the number of known LWPs in the tgid given by PID. */
359 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
360 if (ptid_get_pid (lp
->ptid
) == pid
)
366 /* Call delete_lwp with prototype compatible for make_cleanup. */
369 delete_lwp_cleanup (void *lp_voidp
)
371 struct lwp_info
*lp
= lp_voidp
;
373 delete_lwp (lp
->ptid
);
376 /* Target hook for follow_fork. On entry inferior_ptid must be the
377 ptid of the followed inferior. At return, inferior_ptid will be
381 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
,
386 struct lwp_info
*child_lp
= NULL
;
387 int status
= W_STOPCODE (0);
388 struct cleanup
*old_chain
;
390 int parent_pid
, child_pid
;
392 has_vforked
= (inferior_thread ()->pending_follow
.kind
393 == TARGET_WAITKIND_VFORKED
);
394 parent_pid
= ptid_get_lwp (inferior_ptid
);
396 parent_pid
= ptid_get_pid (inferior_ptid
);
398 = ptid_get_pid (inferior_thread ()->pending_follow
.value
.related_pid
);
401 /* We're already attached to the parent, by default. */
402 old_chain
= save_inferior_ptid ();
403 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
404 child_lp
= add_lwp (inferior_ptid
);
405 child_lp
->stopped
= 1;
406 child_lp
->last_resume_kind
= resume_stop
;
408 /* Detach new forked process? */
411 make_cleanup (delete_lwp_cleanup
, child_lp
);
413 if (linux_nat_prepare_to_resume
!= NULL
)
414 linux_nat_prepare_to_resume (child_lp
);
416 /* When debugging an inferior in an architecture that supports
417 hardware single stepping on a kernel without commit
418 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
419 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
420 set if the parent process had them set.
421 To work around this, single step the child process
422 once before detaching to clear the flags. */
424 if (!gdbarch_software_single_step_p (target_thread_architecture
427 linux_disable_event_reporting (child_pid
);
428 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
429 perror_with_name (_("Couldn't do single step"));
430 if (my_waitpid (child_pid
, &status
, 0) < 0)
431 perror_with_name (_("Couldn't wait vfork process"));
434 if (WIFSTOPPED (status
))
438 signo
= WSTOPSIG (status
);
440 && !signal_pass_state (gdb_signal_from_host (signo
)))
442 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
445 /* Resets value of inferior_ptid to parent ptid. */
446 do_cleanups (old_chain
);
450 /* Let the thread_db layer learn about this new process. */
451 check_for_thread_db ();
454 do_cleanups (old_chain
);
458 struct lwp_info
*parent_lp
;
460 parent_lp
= find_lwp_pid (pid_to_ptid (parent_pid
));
461 gdb_assert (linux_supports_tracefork () >= 0);
463 if (linux_supports_tracevforkdone ())
466 fprintf_unfiltered (gdb_stdlog
,
467 "LCFF: waiting for VFORK_DONE on %d\n",
469 parent_lp
->stopped
= 1;
471 /* We'll handle the VFORK_DONE event like any other
472 event, in target_wait. */
476 /* We can't insert breakpoints until the child has
477 finished with the shared memory region. We need to
478 wait until that happens. Ideal would be to just
480 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
481 - waitpid (parent_pid, &status, __WALL);
482 However, most architectures can't handle a syscall
483 being traced on the way out if it wasn't traced on
486 We might also think to loop, continuing the child
487 until it exits or gets a SIGTRAP. One problem is
488 that the child might call ptrace with PTRACE_TRACEME.
490 There's no simple and reliable way to figure out when
491 the vforked child will be done with its copy of the
492 shared memory. We could step it out of the syscall,
493 two instructions, let it go, and then single-step the
494 parent once. When we have hardware single-step, this
495 would work; with software single-step it could still
496 be made to work but we'd have to be able to insert
497 single-step breakpoints in the child, and we'd have
498 to insert -just- the single-step breakpoint in the
499 parent. Very awkward.
501 In the end, the best we can do is to make sure it
502 runs for a little while. Hopefully it will be out of
503 range of any breakpoints we reinsert. Usually this
504 is only the single-step breakpoint at vfork's return
508 fprintf_unfiltered (gdb_stdlog
,
509 "LCFF: no VFORK_DONE "
510 "support, sleeping a bit\n");
514 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
515 and leave it pending. The next linux_nat_resume call
516 will notice a pending event, and bypasses actually
517 resuming the inferior. */
518 parent_lp
->status
= 0;
519 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
520 parent_lp
->stopped
= 1;
522 /* If we're in async mode, need to tell the event loop
523 there's something here to process. */
524 if (target_is_async_p ())
531 struct lwp_info
*child_lp
;
533 child_lp
= add_lwp (inferior_ptid
);
534 child_lp
->stopped
= 1;
535 child_lp
->last_resume_kind
= resume_stop
;
537 /* Let the thread_db layer learn about this new process. */
538 check_for_thread_db ();
546 linux_child_insert_fork_catchpoint (struct target_ops
*self
, int pid
)
548 return !linux_supports_tracefork ();
552 linux_child_remove_fork_catchpoint (struct target_ops
*self
, int pid
)
558 linux_child_insert_vfork_catchpoint (struct target_ops
*self
, int pid
)
560 return !linux_supports_tracefork ();
564 linux_child_remove_vfork_catchpoint (struct target_ops
*self
, int pid
)
570 linux_child_insert_exec_catchpoint (struct target_ops
*self
, int pid
)
572 return !linux_supports_tracefork ();
576 linux_child_remove_exec_catchpoint (struct target_ops
*self
, int pid
)
582 linux_child_set_syscall_catchpoint (struct target_ops
*self
,
583 int pid
, int needed
, int any_count
,
584 int table_size
, int *table
)
586 if (!linux_supports_tracesysgood ())
589 /* On GNU/Linux, we ignore the arguments. It means that we only
590 enable the syscall catchpoints, but do not disable them.
592 Also, we do not use the `table' information because we do not
593 filter system calls here. We let GDB do the logic for us. */
597 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
598 are processes sharing the same VM space. A multi-threaded process
599 is basically a group of such processes. However, such a grouping
600 is almost entirely a user-space issue; the kernel doesn't enforce
601 such a grouping at all (this might change in the future). In
602 general, we'll rely on the threads library (i.e. the GNU/Linux
603 Threads library) to provide such a grouping.
605 It is perfectly well possible to write a multi-threaded application
606 without the assistance of a threads library, by using the clone
607 system call directly. This module should be able to give some
608 rudimentary support for debugging such applications if developers
609 specify the CLONE_PTRACE flag in the clone system call, and are
610 using the Linux kernel 2.4 or above.
612 Note that there are some peculiarities in GNU/Linux that affect
615 - In general one should specify the __WCLONE flag to waitpid in
616 order to make it report events for any of the cloned processes
617 (and leave it out for the initial process). However, if a cloned
618 process has exited the exit status is only reported if the
619 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
620 we cannot use it since GDB must work on older systems too.
622 - When a traced, cloned process exits and is waited for by the
623 debugger, the kernel reassigns it to the original parent and
624 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
625 library doesn't notice this, which leads to the "zombie problem":
626 When debugged a multi-threaded process that spawns a lot of
627 threads will run out of processes, even if the threads exit,
628 because the "zombies" stay around. */
630 /* List of known LWPs. */
631 struct lwp_info
*lwp_list
;
634 /* Original signal mask. */
635 static sigset_t normal_mask
;
637 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
638 _initialize_linux_nat. */
639 static sigset_t suspend_mask
;
641 /* Signals to block to make that sigsuspend work. */
642 static sigset_t blocked_mask
;
644 /* SIGCHLD action. */
645 struct sigaction sigchld_action
;
647 /* Block child signals (SIGCHLD and linux threads signals), and store
648 the previous mask in PREV_MASK. */
651 block_child_signals (sigset_t
*prev_mask
)
653 /* Make sure SIGCHLD is blocked. */
654 if (!sigismember (&blocked_mask
, SIGCHLD
))
655 sigaddset (&blocked_mask
, SIGCHLD
);
657 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
660 /* Restore child signals mask, previously returned by
661 block_child_signals. */
664 restore_child_signals_mask (sigset_t
*prev_mask
)
666 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
669 /* Mask of signals to pass directly to the inferior. */
670 static sigset_t pass_mask
;
672 /* Update signals to pass to the inferior. */
674 linux_nat_pass_signals (struct target_ops
*self
,
675 int numsigs
, unsigned char *pass_signals
)
679 sigemptyset (&pass_mask
);
681 for (signo
= 1; signo
< NSIG
; signo
++)
683 int target_signo
= gdb_signal_from_host (signo
);
684 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
685 sigaddset (&pass_mask
, signo
);
691 /* Prototypes for local functions. */
692 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
693 static int linux_thread_alive (ptid_t ptid
);
694 static char *linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
);
695 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
);
699 /* Destroy and free LP. */
702 lwp_free (struct lwp_info
*lp
)
704 xfree (lp
->arch_private
);
708 /* Remove all LWPs belong to PID from the lwp list. */
711 purge_lwp_list (int pid
)
713 struct lwp_info
*lp
, *lpprev
, *lpnext
;
717 for (lp
= lwp_list
; lp
; lp
= lpnext
)
721 if (ptid_get_pid (lp
->ptid
) == pid
)
726 lpprev
->next
= lp
->next
;
735 /* Add the LWP specified by PTID to the list. PTID is the first LWP
736 in the process. Return a pointer to the structure describing the
739 This differs from add_lwp in that we don't let the arch specific
740 bits know about this new thread. Current clients of this callback
741 take the opportunity to install watchpoints in the new thread, and
742 we shouldn't do that for the first thread. If we're spawning a
743 child ("run"), the thread executes the shell wrapper first, and we
744 shouldn't touch it until it execs the program we want to debug.
745 For "attach", it'd be okay to call the callback, but it's not
746 necessary, because watchpoints can't yet have been inserted into
749 static struct lwp_info
*
750 add_initial_lwp (ptid_t ptid
)
754 gdb_assert (ptid_lwp_p (ptid
));
756 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
758 memset (lp
, 0, sizeof (struct lwp_info
));
760 lp
->last_resume_kind
= resume_continue
;
761 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
772 /* Add the LWP specified by PID to the list. Return a pointer to the
773 structure describing the new LWP. The LWP should already be
776 static struct lwp_info
*
777 add_lwp (ptid_t ptid
)
781 lp
= add_initial_lwp (ptid
);
783 /* Let the arch specific bits know about this new thread. Current
784 clients of this callback take the opportunity to install
785 watchpoints in the new thread. We don't do this for the first
786 thread though. See add_initial_lwp. */
787 if (linux_nat_new_thread
!= NULL
)
788 linux_nat_new_thread (lp
);
793 /* Remove the LWP specified by PID from the list. */
796 delete_lwp (ptid_t ptid
)
798 struct lwp_info
*lp
, *lpprev
;
802 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
803 if (ptid_equal (lp
->ptid
, ptid
))
810 lpprev
->next
= lp
->next
;
817 /* Return a pointer to the structure describing the LWP corresponding
818 to PID. If no corresponding LWP could be found, return NULL. */
820 static struct lwp_info
*
821 find_lwp_pid (ptid_t ptid
)
826 if (ptid_lwp_p (ptid
))
827 lwp
= ptid_get_lwp (ptid
);
829 lwp
= ptid_get_pid (ptid
);
831 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
832 if (lwp
== ptid_get_lwp (lp
->ptid
))
838 /* Call CALLBACK with its second argument set to DATA for every LWP in
839 the list. If CALLBACK returns 1 for a particular LWP, return a
840 pointer to the structure describing that LWP immediately.
841 Otherwise return NULL. */
844 iterate_over_lwps (ptid_t filter
,
845 int (*callback
) (struct lwp_info
*, void *),
848 struct lwp_info
*lp
, *lpnext
;
850 for (lp
= lwp_list
; lp
; lp
= lpnext
)
854 if (ptid_match (lp
->ptid
, filter
))
856 if ((*callback
) (lp
, data
))
864 /* Update our internal state when changing from one checkpoint to
865 another indicated by NEW_PTID. We can only switch single-threaded
866 applications, so we only create one new LWP, and the previous list
870 linux_nat_switch_fork (ptid_t new_ptid
)
874 purge_lwp_list (ptid_get_pid (inferior_ptid
));
876 lp
= add_lwp (new_ptid
);
879 /* This changes the thread's ptid while preserving the gdb thread
880 num. Also changes the inferior pid, while preserving the
882 thread_change_ptid (inferior_ptid
, new_ptid
);
884 /* We've just told GDB core that the thread changed target id, but,
885 in fact, it really is a different thread, with different register
887 registers_changed ();
890 /* Handle the exit of a single thread LP. */
893 exit_lwp (struct lwp_info
*lp
)
895 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
899 if (print_thread_events
)
900 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
902 delete_thread (lp
->ptid
);
905 delete_lwp (lp
->ptid
);
908 /* Wait for the LWP specified by LP, which we have just attached to.
909 Returns a wait status for that LWP, to cache. */
912 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
915 pid_t new_pid
, pid
= ptid_get_lwp (ptid
);
918 if (linux_proc_pid_is_stopped (pid
))
921 fprintf_unfiltered (gdb_stdlog
,
922 "LNPAW: Attaching to a stopped process\n");
924 /* The process is definitely stopped. It is in a job control
925 stop, unless the kernel predates the TASK_STOPPED /
926 TASK_TRACED distinction, in which case it might be in a
927 ptrace stop. Make sure it is in a ptrace stop; from there we
928 can kill it, signal it, et cetera.
930 First make sure there is a pending SIGSTOP. Since we are
931 already attached, the process can not transition from stopped
932 to running without a PTRACE_CONT; so we know this signal will
933 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
934 probably already in the queue (unless this kernel is old
935 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
936 is not an RT signal, it can only be queued once. */
937 kill_lwp (pid
, SIGSTOP
);
939 /* Finally, resume the stopped process. This will deliver the SIGSTOP
940 (or a higher priority signal, just like normal PTRACE_ATTACH). */
941 ptrace (PTRACE_CONT
, pid
, 0, 0);
944 /* Make sure the initial process is stopped. The user-level threads
945 layer might want to poke around in the inferior, and that won't
946 work if things haven't stabilized yet. */
947 new_pid
= my_waitpid (pid
, &status
, 0);
948 if (new_pid
== -1 && errno
== ECHILD
)
951 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
953 /* Try again with __WCLONE to check cloned processes. */
954 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
958 gdb_assert (pid
== new_pid
);
960 if (!WIFSTOPPED (status
))
962 /* The pid we tried to attach has apparently just exited. */
964 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
965 pid
, status_to_str (status
));
969 if (WSTOPSIG (status
) != SIGSTOP
)
973 fprintf_unfiltered (gdb_stdlog
,
974 "LNPAW: Received %s after attaching\n",
975 status_to_str (status
));
981 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
982 the new LWP could not be attached, or 1 if we're already auto
983 attached to this thread, but haven't processed the
984 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
985 its existance, without considering it an error. */
988 lin_lwp_attach_lwp (ptid_t ptid
)
993 gdb_assert (ptid_lwp_p (ptid
));
995 lp
= find_lwp_pid (ptid
);
996 lwpid
= ptid_get_lwp (ptid
);
998 /* We assume that we're already attached to any LWP that is already
999 in our list of LWPs. If we're not seeing exit events from threads
1000 and we've had PID wraparound since we last tried to stop all threads,
1001 this assumption might be wrong; fortunately, this is very unlikely
1005 int status
, cloned
= 0, signalled
= 0;
1007 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1009 if (linux_supports_tracefork ())
1011 /* If we haven't stopped all threads when we get here,
1012 we may have seen a thread listed in thread_db's list,
1013 but not processed the PTRACE_EVENT_CLONE yet. If
1014 that's the case, ignore this new thread, and let
1015 normal event handling discover it later. */
1016 if (in_pid_list_p (stopped_pids
, lwpid
))
1018 /* We've already seen this thread stop, but we
1019 haven't seen the PTRACE_EVENT_CLONE extended
1021 if (debug_linux_nat
)
1022 fprintf_unfiltered (gdb_stdlog
,
1023 "LLAL: attach failed, but already seen "
1024 "this thread %s stop\n",
1025 target_pid_to_str (ptid
));
1033 if (debug_linux_nat
)
1034 fprintf_unfiltered (gdb_stdlog
,
1035 "LLAL: attach failed, and haven't seen "
1036 "this thread %s stop yet\n",
1037 target_pid_to_str (ptid
));
1039 /* We may or may not be attached to the LWP already.
1040 Try waitpid on it. If that errors, we're not
1041 attached to the LWP yet. Otherwise, we're
1042 already attached. */
1043 gdb_assert (lwpid
> 0);
1044 new_pid
= my_waitpid (lwpid
, &status
, WNOHANG
);
1045 if (new_pid
== -1 && errno
== ECHILD
)
1046 new_pid
= my_waitpid (lwpid
, &status
, __WCLONE
| WNOHANG
);
1051 /* The child hasn't stopped for its initial
1052 SIGSTOP stop yet. */
1053 if (debug_linux_nat
)
1054 fprintf_unfiltered (gdb_stdlog
,
1055 "LLAL: child hasn't "
1058 else if (WIFSTOPPED (status
))
1060 if (debug_linux_nat
)
1061 fprintf_unfiltered (gdb_stdlog
,
1062 "LLAL: adding to stopped_pids\n");
1063 add_to_pid_list (&stopped_pids
, lwpid
, status
);
1070 /* If we fail to attach to the thread, issue a warning,
1071 but continue. One way this can happen is if thread
1072 creation is interrupted; as of Linux kernel 2.6.19, a
1073 bug may place threads in the thread list and then fail
1075 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1076 safe_strerror (errno
));
1080 if (debug_linux_nat
)
1081 fprintf_unfiltered (gdb_stdlog
,
1082 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1083 target_pid_to_str (ptid
));
1085 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1086 if (!WIFSTOPPED (status
))
1089 lp
= add_lwp (ptid
);
1091 lp
->last_resume_kind
= resume_stop
;
1092 lp
->cloned
= cloned
;
1093 lp
->signalled
= signalled
;
1094 if (WSTOPSIG (status
) != SIGSTOP
)
1097 lp
->status
= status
;
1100 target_post_attach (ptid_get_lwp (lp
->ptid
));
1102 if (debug_linux_nat
)
1104 fprintf_unfiltered (gdb_stdlog
,
1105 "LLAL: waitpid %s received %s\n",
1106 target_pid_to_str (ptid
),
1107 status_to_str (status
));
1115 linux_nat_create_inferior (struct target_ops
*ops
,
1116 char *exec_file
, char *allargs
, char **env
,
1119 struct cleanup
*restore_personality
1120 = maybe_disable_address_space_randomization (disable_randomization
);
1122 /* The fork_child mechanism is synchronous and calls target_wait, so
1123 we have to mask the async mode. */
1125 /* Make sure we report all signals during startup. */
1126 linux_nat_pass_signals (ops
, 0, NULL
);
1128 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1130 do_cleanups (restore_personality
);
1133 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1134 already attached. Returns true if a new LWP is found, false
1138 attach_proc_task_lwp_callback (ptid_t ptid
)
1140 struct lwp_info
*lp
;
1142 /* Ignore LWPs we're already attached to. */
1143 lp
= find_lwp_pid (ptid
);
1146 int lwpid
= ptid_get_lwp (ptid
);
1148 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1152 /* Be quiet if we simply raced with the thread exiting.
1153 EPERM is returned if the thread's task still exists, and
1154 is marked as exited or zombie, as well as other
1155 conditions, so in that case, confirm the status in
1156 /proc/PID/status. */
1158 || (err
== EPERM
&& linux_proc_pid_is_gone (lwpid
)))
1160 if (debug_linux_nat
)
1162 fprintf_unfiltered (gdb_stdlog
,
1163 "Cannot attach to lwp %d: "
1164 "thread is gone (%d: %s)\n",
1165 lwpid
, err
, safe_strerror (err
));
1170 warning (_("Cannot attach to lwp %d: %s"),
1172 linux_ptrace_attach_fail_reason_string (ptid
,
1178 if (debug_linux_nat
)
1179 fprintf_unfiltered (gdb_stdlog
,
1180 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1181 target_pid_to_str (ptid
));
1183 lp
= add_lwp (ptid
);
1186 /* The next time we wait for this LWP we'll see a SIGSTOP as
1187 PTRACE_ATTACH brings it to a halt. */
1190 /* We need to wait for a stop before being able to make the
1191 next ptrace call on this LWP. */
1192 lp
->must_set_ptrace_flags
= 1;
1201 linux_nat_attach (struct target_ops
*ops
, const char *args
, int from_tty
)
1203 struct lwp_info
*lp
;
1206 volatile struct gdb_exception ex
;
1208 /* Make sure we report all signals during attach. */
1209 linux_nat_pass_signals (ops
, 0, NULL
);
1211 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
1213 linux_ops
->to_attach (ops
, args
, from_tty
);
1217 pid_t pid
= parse_pid_to_attach (args
);
1218 struct buffer buffer
;
1219 char *message
, *buffer_s
;
1221 message
= xstrdup (ex
.message
);
1222 make_cleanup (xfree
, message
);
1224 buffer_init (&buffer
);
1225 linux_ptrace_attach_fail_reason (pid
, &buffer
);
1227 buffer_grow_str0 (&buffer
, "");
1228 buffer_s
= buffer_finish (&buffer
);
1229 make_cleanup (xfree
, buffer_s
);
1231 if (*buffer_s
!= '\0')
1232 throw_error (ex
.error
, "warning: %s\n%s", buffer_s
, message
);
1234 throw_error (ex
.error
, "%s", message
);
1237 /* The ptrace base target adds the main thread with (pid,0,0)
1238 format. Decorate it with lwp info. */
1239 ptid
= ptid_build (ptid_get_pid (inferior_ptid
),
1240 ptid_get_pid (inferior_ptid
),
1242 thread_change_ptid (inferior_ptid
, ptid
);
1244 /* Add the initial process as the first LWP to the list. */
1245 lp
= add_initial_lwp (ptid
);
1247 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1249 if (!WIFSTOPPED (status
))
1251 if (WIFEXITED (status
))
1253 int exit_code
= WEXITSTATUS (status
);
1255 target_terminal_ours ();
1256 target_mourn_inferior ();
1258 error (_("Unable to attach: program exited normally."));
1260 error (_("Unable to attach: program exited with code %d."),
1263 else if (WIFSIGNALED (status
))
1265 enum gdb_signal signo
;
1267 target_terminal_ours ();
1268 target_mourn_inferior ();
1270 signo
= gdb_signal_from_host (WTERMSIG (status
));
1271 error (_("Unable to attach: program terminated with signal "
1273 gdb_signal_to_name (signo
),
1274 gdb_signal_to_string (signo
));
1277 internal_error (__FILE__
, __LINE__
,
1278 _("unexpected status %d for PID %ld"),
1279 status
, (long) ptid_get_lwp (ptid
));
1284 /* Save the wait status to report later. */
1286 if (debug_linux_nat
)
1287 fprintf_unfiltered (gdb_stdlog
,
1288 "LNA: waitpid %ld, saving status %s\n",
1289 (long) ptid_get_pid (lp
->ptid
), status_to_str (status
));
1291 lp
->status
= status
;
1293 /* We must attach to every LWP. If /proc is mounted, use that to
1294 find them now. The inferior may be using raw clone instead of
1295 using pthreads. But even if it is using pthreads, thread_db
1296 walks structures in the inferior's address space to find the list
1297 of threads/LWPs, and those structures may well be corrupted.
1298 Note that once thread_db is loaded, we'll still use it to list
1299 threads and associate pthread info with each LWP. */
1300 linux_proc_attach_tgid_threads (ptid_get_pid (lp
->ptid
),
1301 attach_proc_task_lwp_callback
);
1303 if (target_can_async_p ())
1304 target_async (inferior_event_handler
, 0);
1307 /* Get pending status of LP. */
1309 get_pending_status (struct lwp_info
*lp
, int *status
)
1311 enum gdb_signal signo
= GDB_SIGNAL_0
;
1313 /* If we paused threads momentarily, we may have stored pending
1314 events in lp->status or lp->waitstatus (see stop_wait_callback),
1315 and GDB core hasn't seen any signal for those threads.
1316 Otherwise, the last signal reported to the core is found in the
1317 thread object's stop_signal.
1319 There's a corner case that isn't handled here at present. Only
1320 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1321 stop_signal make sense as a real signal to pass to the inferior.
1322 Some catchpoint related events, like
1323 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1324 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1325 those traps are debug API (ptrace in our case) related and
1326 induced; the inferior wouldn't see them if it wasn't being
1327 traced. Hence, we should never pass them to the inferior, even
1328 when set to pass state. Since this corner case isn't handled by
1329 infrun.c when proceeding with a signal, for consistency, neither
1330 do we handle it here (or elsewhere in the file we check for
1331 signal pass state). Normally SIGTRAP isn't set to pass state, so
1332 this is really a corner case. */
1334 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1335 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1336 else if (lp
->status
)
1337 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1338 else if (non_stop
&& !is_executing (lp
->ptid
))
1340 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1342 signo
= tp
->suspend
.stop_signal
;
1346 struct target_waitstatus last
;
1349 get_last_target_status (&last_ptid
, &last
);
1351 if (ptid_get_lwp (lp
->ptid
) == ptid_get_lwp (last_ptid
))
1353 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1355 signo
= tp
->suspend
.stop_signal
;
1361 if (signo
== GDB_SIGNAL_0
)
1363 if (debug_linux_nat
)
1364 fprintf_unfiltered (gdb_stdlog
,
1365 "GPT: lwp %s has no pending signal\n",
1366 target_pid_to_str (lp
->ptid
));
1368 else if (!signal_pass_state (signo
))
1370 if (debug_linux_nat
)
1371 fprintf_unfiltered (gdb_stdlog
,
1372 "GPT: lwp %s had signal %s, "
1373 "but it is in no pass state\n",
1374 target_pid_to_str (lp
->ptid
),
1375 gdb_signal_to_string (signo
));
1379 *status
= W_STOPCODE (gdb_signal_to_host (signo
));
1381 if (debug_linux_nat
)
1382 fprintf_unfiltered (gdb_stdlog
,
1383 "GPT: lwp %s has pending signal %s\n",
1384 target_pid_to_str (lp
->ptid
),
1385 gdb_signal_to_string (signo
));
1392 detach_callback (struct lwp_info
*lp
, void *data
)
1394 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1396 if (debug_linux_nat
&& lp
->status
)
1397 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1398 strsignal (WSTOPSIG (lp
->status
)),
1399 target_pid_to_str (lp
->ptid
));
1401 /* If there is a pending SIGSTOP, get rid of it. */
1404 if (debug_linux_nat
)
1405 fprintf_unfiltered (gdb_stdlog
,
1406 "DC: Sending SIGCONT to %s\n",
1407 target_pid_to_str (lp
->ptid
));
1409 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGCONT
);
1413 /* We don't actually detach from the LWP that has an id equal to the
1414 overall process id just yet. */
1415 if (ptid_get_lwp (lp
->ptid
) != ptid_get_pid (lp
->ptid
))
1419 /* Pass on any pending signal for this LWP. */
1420 get_pending_status (lp
, &status
);
1422 if (linux_nat_prepare_to_resume
!= NULL
)
1423 linux_nat_prepare_to_resume (lp
);
1425 if (ptrace (PTRACE_DETACH
, ptid_get_lwp (lp
->ptid
), 0,
1426 WSTOPSIG (status
)) < 0)
1427 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1428 safe_strerror (errno
));
1430 if (debug_linux_nat
)
1431 fprintf_unfiltered (gdb_stdlog
,
1432 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1433 target_pid_to_str (lp
->ptid
),
1434 strsignal (WSTOPSIG (status
)));
1436 delete_lwp (lp
->ptid
);
1443 linux_nat_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1447 struct lwp_info
*main_lwp
;
1449 pid
= ptid_get_pid (inferior_ptid
);
1451 /* Don't unregister from the event loop, as there may be other
1452 inferiors running. */
1454 /* Stop all threads before detaching. ptrace requires that the
1455 thread is stopped to sucessfully detach. */
1456 iterate_over_lwps (pid_to_ptid (pid
), stop_callback
, NULL
);
1457 /* ... and wait until all of them have reported back that
1458 they're no longer running. */
1459 iterate_over_lwps (pid_to_ptid (pid
), stop_wait_callback
, NULL
);
1461 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1463 /* Only the initial process should be left right now. */
1464 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid
)) == 1);
1466 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
1468 /* Pass on any pending signal for the last LWP. */
1469 if ((args
== NULL
|| *args
== '\0')
1470 && get_pending_status (main_lwp
, &status
) != -1
1471 && WIFSTOPPED (status
))
1475 /* Put the signal number in ARGS so that inf_ptrace_detach will
1476 pass it along with PTRACE_DETACH. */
1478 xsnprintf (tem
, 8, "%d", (int) WSTOPSIG (status
));
1480 if (debug_linux_nat
)
1481 fprintf_unfiltered (gdb_stdlog
,
1482 "LND: Sending signal %s to %s\n",
1484 target_pid_to_str (main_lwp
->ptid
));
1487 if (linux_nat_prepare_to_resume
!= NULL
)
1488 linux_nat_prepare_to_resume (main_lwp
);
1489 delete_lwp (main_lwp
->ptid
);
1491 if (forks_exist_p ())
1493 /* Multi-fork case. The current inferior_ptid is being detached
1494 from, but there are other viable forks to debug. Detach from
1495 the current fork, and context-switch to the first
1497 linux_fork_detach (args
, from_tty
);
1500 linux_ops
->to_detach (ops
, args
, from_tty
);
1503 /* Resume execution of the inferior process. If STEP is nonzero,
1504 single-step it. If SIGNAL is nonzero, give it that signal. */
1507 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1513 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1514 We only presently need that if the LWP is stepped though (to
1515 handle the case of stepping a breakpoint instruction). */
1518 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
1520 lp
->stop_pc
= regcache_read_pc (regcache
);
1525 if (linux_nat_prepare_to_resume
!= NULL
)
1526 linux_nat_prepare_to_resume (lp
);
1527 /* Convert to something the lower layer understands. */
1528 ptid
= pid_to_ptid (ptid_get_lwp (lp
->ptid
));
1529 linux_ops
->to_resume (linux_ops
, ptid
, step
, signo
);
1530 lp
->stop_reason
= LWP_STOPPED_BY_NO_REASON
;
1532 registers_changed_ptid (lp
->ptid
);
1538 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1542 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
1544 if (inf
->vfork_child
!= NULL
)
1546 if (debug_linux_nat
)
1547 fprintf_unfiltered (gdb_stdlog
,
1548 "RC: Not resuming %s (vfork parent)\n",
1549 target_pid_to_str (lp
->ptid
));
1551 else if (!lwp_status_pending_p (lp
))
1553 if (debug_linux_nat
)
1554 fprintf_unfiltered (gdb_stdlog
,
1555 "RC: Resuming sibling %s, %s, %s\n",
1556 target_pid_to_str (lp
->ptid
),
1557 (signo
!= GDB_SIGNAL_0
1558 ? strsignal (gdb_signal_to_host (signo
))
1560 step
? "step" : "resume");
1562 linux_resume_one_lwp (lp
, step
, signo
);
1566 if (debug_linux_nat
)
1567 fprintf_unfiltered (gdb_stdlog
,
1568 "RC: Not resuming sibling %s (has pending)\n",
1569 target_pid_to_str (lp
->ptid
));
1574 if (debug_linux_nat
)
1575 fprintf_unfiltered (gdb_stdlog
,
1576 "RC: Not resuming sibling %s (not stopped)\n",
1577 target_pid_to_str (lp
->ptid
));
1581 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1582 Resume LWP with the last stop signal, if it is in pass state. */
1585 linux_nat_resume_callback (struct lwp_info
*lp
, void *except
)
1587 enum gdb_signal signo
= GDB_SIGNAL_0
;
1594 struct thread_info
*thread
;
1596 thread
= find_thread_ptid (lp
->ptid
);
1599 signo
= thread
->suspend
.stop_signal
;
1600 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1604 resume_lwp (lp
, 0, signo
);
1609 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1612 lp
->last_resume_kind
= resume_stop
;
1617 resume_set_callback (struct lwp_info
*lp
, void *data
)
1620 lp
->last_resume_kind
= resume_continue
;
1625 linux_nat_resume (struct target_ops
*ops
,
1626 ptid_t ptid
, int step
, enum gdb_signal signo
)
1628 struct lwp_info
*lp
;
1631 if (debug_linux_nat
)
1632 fprintf_unfiltered (gdb_stdlog
,
1633 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1634 step
? "step" : "resume",
1635 target_pid_to_str (ptid
),
1636 (signo
!= GDB_SIGNAL_0
1637 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1638 target_pid_to_str (inferior_ptid
));
1640 /* A specific PTID means `step only this process id'. */
1641 resume_many
= (ptid_equal (minus_one_ptid
, ptid
)
1642 || ptid_is_pid (ptid
));
1644 /* Mark the lwps we're resuming as resumed. */
1645 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1647 /* See if it's the current inferior that should be handled
1650 lp
= find_lwp_pid (inferior_ptid
);
1652 lp
= find_lwp_pid (ptid
);
1653 gdb_assert (lp
!= NULL
);
1655 /* Remember if we're stepping. */
1656 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1658 /* If we have a pending wait status for this thread, there is no
1659 point in resuming the process. But first make sure that
1660 linux_nat_wait won't preemptively handle the event - we
1661 should never take this short-circuit if we are going to
1662 leave LP running, since we have skipped resuming all the
1663 other threads. This bit of code needs to be synchronized
1664 with linux_nat_wait. */
1666 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1669 && WSTOPSIG (lp
->status
)
1670 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1672 if (debug_linux_nat
)
1673 fprintf_unfiltered (gdb_stdlog
,
1674 "LLR: Not short circuiting for ignored "
1675 "status 0x%x\n", lp
->status
);
1677 /* FIXME: What should we do if we are supposed to continue
1678 this thread with a signal? */
1679 gdb_assert (signo
== GDB_SIGNAL_0
);
1680 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1685 if (lwp_status_pending_p (lp
))
1687 /* FIXME: What should we do if we are supposed to continue
1688 this thread with a signal? */
1689 gdb_assert (signo
== GDB_SIGNAL_0
);
1691 if (debug_linux_nat
)
1692 fprintf_unfiltered (gdb_stdlog
,
1693 "LLR: Short circuiting for status 0x%x\n",
1696 if (target_can_async_p ())
1698 target_async (inferior_event_handler
, 0);
1699 /* Tell the event loop we have something to process. */
1706 iterate_over_lwps (ptid
, linux_nat_resume_callback
, lp
);
1708 linux_resume_one_lwp (lp
, step
, signo
);
1710 if (debug_linux_nat
)
1711 fprintf_unfiltered (gdb_stdlog
,
1712 "LLR: %s %s, %s (resume event thread)\n",
1713 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1714 target_pid_to_str (ptid
),
1715 (signo
!= GDB_SIGNAL_0
1716 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1718 if (target_can_async_p ())
1719 target_async (inferior_event_handler
, 0);
1722 /* Send a signal to an LWP. */
1725 kill_lwp (int lwpid
, int signo
)
1727 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1728 fails, then we are not using nptl threads and we should be using kill. */
1730 #ifdef HAVE_TKILL_SYSCALL
1732 static int tkill_failed
;
1739 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1740 if (errno
!= ENOSYS
)
1747 return kill (lwpid
, signo
);
1750 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1751 event, check if the core is interested in it: if not, ignore the
1752 event, and keep waiting; otherwise, we need to toggle the LWP's
1753 syscall entry/exit status, since the ptrace event itself doesn't
1754 indicate it, and report the trap to higher layers. */
1757 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1759 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1760 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1761 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, lp
->ptid
);
1765 /* If we're stopping threads, there's a SIGSTOP pending, which
1766 makes it so that the LWP reports an immediate syscall return,
1767 followed by the SIGSTOP. Skip seeing that "return" using
1768 PTRACE_CONT directly, and let stop_wait_callback collect the
1769 SIGSTOP. Later when the thread is resumed, a new syscall
1770 entry event. If we didn't do this (and returned 0), we'd
1771 leave a syscall entry pending, and our caller, by using
1772 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1773 itself. Later, when the user re-resumes this LWP, we'd see
1774 another syscall entry event and we'd mistake it for a return.
1776 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1777 (leaving immediately with LWP->signalled set, without issuing
1778 a PTRACE_CONT), it would still be problematic to leave this
1779 syscall enter pending, as later when the thread is resumed,
1780 it would then see the same syscall exit mentioned above,
1781 followed by the delayed SIGSTOP, while the syscall didn't
1782 actually get to execute. It seems it would be even more
1783 confusing to the user. */
1785 if (debug_linux_nat
)
1786 fprintf_unfiltered (gdb_stdlog
,
1787 "LHST: ignoring syscall %d "
1788 "for LWP %ld (stopping threads), "
1789 "resuming with PTRACE_CONT for SIGSTOP\n",
1791 ptid_get_lwp (lp
->ptid
));
1793 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1794 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
1799 if (catch_syscall_enabled ())
1801 /* Always update the entry/return state, even if this particular
1802 syscall isn't interesting to the core now. In async mode,
1803 the user could install a new catchpoint for this syscall
1804 between syscall enter/return, and we'll need to know to
1805 report a syscall return if that happens. */
1806 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1807 ? TARGET_WAITKIND_SYSCALL_RETURN
1808 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1810 if (catching_syscall_number (syscall_number
))
1812 /* Alright, an event to report. */
1813 ourstatus
->kind
= lp
->syscall_state
;
1814 ourstatus
->value
.syscall_number
= syscall_number
;
1816 if (debug_linux_nat
)
1817 fprintf_unfiltered (gdb_stdlog
,
1818 "LHST: stopping for %s of syscall %d"
1821 == TARGET_WAITKIND_SYSCALL_ENTRY
1822 ? "entry" : "return",
1824 ptid_get_lwp (lp
->ptid
));
1828 if (debug_linux_nat
)
1829 fprintf_unfiltered (gdb_stdlog
,
1830 "LHST: ignoring %s of syscall %d "
1832 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1833 ? "entry" : "return",
1835 ptid_get_lwp (lp
->ptid
));
1839 /* If we had been syscall tracing, and hence used PT_SYSCALL
1840 before on this LWP, it could happen that the user removes all
1841 syscall catchpoints before we get to process this event.
1842 There are two noteworthy issues here:
1844 - When stopped at a syscall entry event, resuming with
1845 PT_STEP still resumes executing the syscall and reports a
1848 - Only PT_SYSCALL catches syscall enters. If we last
1849 single-stepped this thread, then this event can't be a
1850 syscall enter. If we last single-stepped this thread, this
1851 has to be a syscall exit.
1853 The points above mean that the next resume, be it PT_STEP or
1854 PT_CONTINUE, can not trigger a syscall trace event. */
1855 if (debug_linux_nat
)
1856 fprintf_unfiltered (gdb_stdlog
,
1857 "LHST: caught syscall event "
1858 "with no syscall catchpoints."
1859 " %d for LWP %ld, ignoring\n",
1861 ptid_get_lwp (lp
->ptid
));
1862 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1865 /* The core isn't interested in this event. For efficiency, avoid
1866 stopping all threads only to have the core resume them all again.
1867 Since we're not stopping threads, if we're still syscall tracing
1868 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1869 subsequent syscall. Simply resume using the inf-ptrace layer,
1870 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1872 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1876 /* Handle a GNU/Linux extended wait response. If we see a clone
1877 event, we need to add the new LWP to our list (and not report the
1878 trap to higher layers). This function returns non-zero if the
1879 event should be ignored and we should wait again. If STOPPING is
1880 true, the new LWP remains stopped, otherwise it is continued. */
1883 linux_handle_extended_wait (struct lwp_info
*lp
, int status
,
1886 int pid
= ptid_get_lwp (lp
->ptid
);
1887 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1888 int event
= linux_ptrace_get_extended_event (status
);
1890 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1891 || event
== PTRACE_EVENT_CLONE
)
1893 unsigned long new_pid
;
1896 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1898 /* If we haven't already seen the new PID stop, wait for it now. */
1899 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1901 /* The new child has a pending SIGSTOP. We can't affect it until it
1902 hits the SIGSTOP, but we're already attached. */
1903 ret
= my_waitpid (new_pid
, &status
,
1904 (event
== PTRACE_EVENT_CLONE
) ? __WCLONE
: 0);
1906 perror_with_name (_("waiting for new child"));
1907 else if (ret
!= new_pid
)
1908 internal_error (__FILE__
, __LINE__
,
1909 _("wait returned unexpected PID %d"), ret
);
1910 else if (!WIFSTOPPED (status
))
1911 internal_error (__FILE__
, __LINE__
,
1912 _("wait returned unexpected status 0x%x"), status
);
1915 ourstatus
->value
.related_pid
= ptid_build (new_pid
, new_pid
, 0);
1917 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1919 /* The arch-specific native code may need to know about new
1920 forks even if those end up never mapped to an
1922 if (linux_nat_new_fork
!= NULL
)
1923 linux_nat_new_fork (lp
, new_pid
);
1926 if (event
== PTRACE_EVENT_FORK
1927 && linux_fork_checkpointing_p (ptid_get_pid (lp
->ptid
)))
1929 /* Handle checkpointing by linux-fork.c here as a special
1930 case. We don't want the follow-fork-mode or 'catch fork'
1931 to interfere with this. */
1933 /* This won't actually modify the breakpoint list, but will
1934 physically remove the breakpoints from the child. */
1935 detach_breakpoints (ptid_build (new_pid
, new_pid
, 0));
1937 /* Retain child fork in ptrace (stopped) state. */
1938 if (!find_fork_pid (new_pid
))
1941 /* Report as spurious, so that infrun doesn't want to follow
1942 this fork. We're actually doing an infcall in
1944 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
1946 /* Report the stop to the core. */
1950 if (event
== PTRACE_EVENT_FORK
)
1951 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
1952 else if (event
== PTRACE_EVENT_VFORK
)
1953 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
1956 struct lwp_info
*new_lp
;
1958 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
1960 if (debug_linux_nat
)
1961 fprintf_unfiltered (gdb_stdlog
,
1962 "LHEW: Got clone event "
1963 "from LWP %d, new child is LWP %ld\n",
1966 new_lp
= add_lwp (ptid_build (ptid_get_pid (lp
->ptid
), new_pid
, 0));
1968 new_lp
->stopped
= 1;
1970 if (WSTOPSIG (status
) != SIGSTOP
)
1972 /* This can happen if someone starts sending signals to
1973 the new thread before it gets a chance to run, which
1974 have a lower number than SIGSTOP (e.g. SIGUSR1).
1975 This is an unlikely case, and harder to handle for
1976 fork / vfork than for clone, so we do not try - but
1977 we handle it for clone events here. We'll send
1978 the other signal on to the thread below. */
1980 new_lp
->signalled
= 1;
1984 struct thread_info
*tp
;
1986 /* When we stop for an event in some other thread, and
1987 pull the thread list just as this thread has cloned,
1988 we'll have seen the new thread in the thread_db list
1989 before handling the CLONE event (glibc's
1990 pthread_create adds the new thread to the thread list
1991 before clone'ing, and has the kernel fill in the
1992 thread's tid on the clone call with
1993 CLONE_PARENT_SETTID). If that happened, and the core
1994 had requested the new thread to stop, we'll have
1995 killed it with SIGSTOP. But since SIGSTOP is not an
1996 RT signal, it can only be queued once. We need to be
1997 careful to not resume the LWP if we wanted it to
1998 stop. In that case, we'll leave the SIGSTOP pending.
1999 It will later be reported as GDB_SIGNAL_0. */
2000 tp
= find_thread_ptid (new_lp
->ptid
);
2001 if (tp
!= NULL
&& tp
->stop_requested
)
2002 new_lp
->last_resume_kind
= resume_stop
;
2007 /* If the thread_db layer is active, let it record the user
2008 level thread id and status, and add the thread to GDB's
2010 if (!thread_db_notice_clone (lp
->ptid
, new_lp
->ptid
))
2012 /* The process is not using thread_db. Add the LWP to
2014 target_post_attach (ptid_get_lwp (new_lp
->ptid
));
2015 add_thread (new_lp
->ptid
);
2020 set_running (new_lp
->ptid
, 1);
2021 set_executing (new_lp
->ptid
, 1);
2022 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2024 new_lp
->last_resume_kind
= resume_continue
;
2029 /* We created NEW_LP so it cannot yet contain STATUS. */
2030 gdb_assert (new_lp
->status
== 0);
2032 /* Save the wait status to report later. */
2033 if (debug_linux_nat
)
2034 fprintf_unfiltered (gdb_stdlog
,
2035 "LHEW: waitpid of new LWP %ld, "
2036 "saving status %s\n",
2037 (long) ptid_get_lwp (new_lp
->ptid
),
2038 status_to_str (status
));
2039 new_lp
->status
= status
;
2042 new_lp
->resumed
= !stopping
;
2049 if (event
== PTRACE_EVENT_EXEC
)
2051 if (debug_linux_nat
)
2052 fprintf_unfiltered (gdb_stdlog
,
2053 "LHEW: Got exec event from LWP %ld\n",
2054 ptid_get_lwp (lp
->ptid
));
2056 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2057 ourstatus
->value
.execd_pathname
2058 = xstrdup (linux_child_pid_to_exec_file (NULL
, pid
));
2060 /* The thread that execed must have been resumed, but, when a
2061 thread execs, it changes its tid to the tgid, and the old
2062 tgid thread might have not been resumed. */
2067 if (event
== PTRACE_EVENT_VFORK_DONE
)
2069 if (current_inferior ()->waiting_for_vfork_done
)
2071 if (debug_linux_nat
)
2072 fprintf_unfiltered (gdb_stdlog
,
2073 "LHEW: Got expected PTRACE_EVENT_"
2074 "VFORK_DONE from LWP %ld: stopping\n",
2075 ptid_get_lwp (lp
->ptid
));
2077 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2081 if (debug_linux_nat
)
2082 fprintf_unfiltered (gdb_stdlog
,
2083 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2084 "from LWP %ld: ignoring\n",
2085 ptid_get_lwp (lp
->ptid
));
2089 internal_error (__FILE__
, __LINE__
,
2090 _("unknown ptrace event %d"), event
);
2093 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2097 wait_lwp (struct lwp_info
*lp
)
2101 int thread_dead
= 0;
2104 gdb_assert (!lp
->stopped
);
2105 gdb_assert (lp
->status
== 0);
2107 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2108 block_child_signals (&prev_mask
);
2112 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2113 was right and we should just call sigsuspend. */
2115 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, WNOHANG
);
2116 if (pid
== -1 && errno
== ECHILD
)
2117 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, __WCLONE
| WNOHANG
);
2118 if (pid
== -1 && errno
== ECHILD
)
2120 /* The thread has previously exited. We need to delete it
2121 now because, for some vendor 2.4 kernels with NPTL
2122 support backported, there won't be an exit event unless
2123 it is the main thread. 2.6 kernels will report an exit
2124 event for each thread that exits, as expected. */
2126 if (debug_linux_nat
)
2127 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2128 target_pid_to_str (lp
->ptid
));
2133 /* Bugs 10970, 12702.
2134 Thread group leader may have exited in which case we'll lock up in
2135 waitpid if there are other threads, even if they are all zombies too.
2136 Basically, we're not supposed to use waitpid this way.
2137 __WCLONE is not applicable for the leader so we can't use that.
2138 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2139 process; it gets ESRCH both for the zombie and for running processes.
2141 As a workaround, check if we're waiting for the thread group leader and
2142 if it's a zombie, and avoid calling waitpid if it is.
2144 This is racy, what if the tgl becomes a zombie right after we check?
2145 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2146 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2148 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
)
2149 && linux_proc_pid_is_zombie (ptid_get_lwp (lp
->ptid
)))
2152 if (debug_linux_nat
)
2153 fprintf_unfiltered (gdb_stdlog
,
2154 "WL: Thread group leader %s vanished.\n",
2155 target_pid_to_str (lp
->ptid
));
2159 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2160 get invoked despite our caller had them intentionally blocked by
2161 block_child_signals. This is sensitive only to the loop of
2162 linux_nat_wait_1 and there if we get called my_waitpid gets called
2163 again before it gets to sigsuspend so we can safely let the handlers
2164 get executed here. */
2166 if (debug_linux_nat
)
2167 fprintf_unfiltered (gdb_stdlog
, "WL: about to sigsuspend\n");
2168 sigsuspend (&suspend_mask
);
2171 restore_child_signals_mask (&prev_mask
);
2175 gdb_assert (pid
== ptid_get_lwp (lp
->ptid
));
2177 if (debug_linux_nat
)
2179 fprintf_unfiltered (gdb_stdlog
,
2180 "WL: waitpid %s received %s\n",
2181 target_pid_to_str (lp
->ptid
),
2182 status_to_str (status
));
2185 /* Check if the thread has exited. */
2186 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2189 if (debug_linux_nat
)
2190 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2191 target_pid_to_str (lp
->ptid
));
2201 gdb_assert (WIFSTOPPED (status
));
2204 if (lp
->must_set_ptrace_flags
)
2206 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2208 linux_enable_event_reporting (ptid_get_lwp (lp
->ptid
), inf
->attach_flag
);
2209 lp
->must_set_ptrace_flags
= 0;
2212 /* Handle GNU/Linux's syscall SIGTRAPs. */
2213 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2215 /* No longer need the sysgood bit. The ptrace event ends up
2216 recorded in lp->waitstatus if we care for it. We can carry
2217 on handling the event like a regular SIGTRAP from here
2219 status
= W_STOPCODE (SIGTRAP
);
2220 if (linux_handle_syscall_trap (lp
, 1))
2221 return wait_lwp (lp
);
2224 /* Handle GNU/Linux's extended waitstatus for trace events. */
2225 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2226 && linux_is_extended_waitstatus (status
))
2228 if (debug_linux_nat
)
2229 fprintf_unfiltered (gdb_stdlog
,
2230 "WL: Handling extended status 0x%06x\n",
2232 linux_handle_extended_wait (lp
, status
, 1);
2239 /* Send a SIGSTOP to LP. */
2242 stop_callback (struct lwp_info
*lp
, void *data
)
2244 if (!lp
->stopped
&& !lp
->signalled
)
2248 if (debug_linux_nat
)
2250 fprintf_unfiltered (gdb_stdlog
,
2251 "SC: kill %s **<SIGSTOP>**\n",
2252 target_pid_to_str (lp
->ptid
));
2255 ret
= kill_lwp (ptid_get_lwp (lp
->ptid
), SIGSTOP
);
2256 if (debug_linux_nat
)
2258 fprintf_unfiltered (gdb_stdlog
,
2259 "SC: lwp kill %d %s\n",
2261 errno
? safe_strerror (errno
) : "ERRNO-OK");
2265 gdb_assert (lp
->status
== 0);
2271 /* Request a stop on LWP. */
2274 linux_stop_lwp (struct lwp_info
*lwp
)
2276 stop_callback (lwp
, NULL
);
2279 /* See linux-nat.h */
2282 linux_stop_and_wait_all_lwps (void)
2284 /* Stop all LWP's ... */
2285 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
2287 /* ... and wait until all of them have reported back that
2288 they're no longer running. */
2289 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
2292 /* See linux-nat.h */
2295 linux_unstop_all_lwps (void)
2297 iterate_over_lwps (minus_one_ptid
,
2298 resume_stopped_resumed_lwps
, &minus_one_ptid
);
2301 /* Return non-zero if LWP PID has a pending SIGINT. */
2304 linux_nat_has_pending_sigint (int pid
)
2306 sigset_t pending
, blocked
, ignored
;
2308 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2310 if (sigismember (&pending
, SIGINT
)
2311 && !sigismember (&ignored
, SIGINT
))
2317 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2320 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2322 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2323 flag to consume the next one. */
2324 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2325 && WSTOPSIG (lp
->status
) == SIGINT
)
2328 lp
->ignore_sigint
= 1;
2333 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2334 This function is called after we know the LWP has stopped; if the LWP
2335 stopped before the expected SIGINT was delivered, then it will never have
2336 arrived. Also, if the signal was delivered to a shared queue and consumed
2337 by a different thread, it will never be delivered to this LWP. */
2340 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2342 if (!lp
->ignore_sigint
)
2345 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp
->ptid
)))
2347 if (debug_linux_nat
)
2348 fprintf_unfiltered (gdb_stdlog
,
2349 "MCIS: Clearing bogus flag for %s\n",
2350 target_pid_to_str (lp
->ptid
));
2351 lp
->ignore_sigint
= 0;
2355 /* Fetch the possible triggered data watchpoint info and store it in
2358 On some archs, like x86, that use debug registers to set
2359 watchpoints, it's possible that the way to know which watched
2360 address trapped, is to check the register that is used to select
2361 which address to watch. Problem is, between setting the watchpoint
2362 and reading back which data address trapped, the user may change
2363 the set of watchpoints, and, as a consequence, GDB changes the
2364 debug registers in the inferior. To avoid reading back a stale
2365 stopped-data-address when that happens, we cache in LP the fact
2366 that a watchpoint trapped, and the corresponding data address, as
2367 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2368 registers meanwhile, we have the cached data we can rely on. */
2371 check_stopped_by_watchpoint (struct lwp_info
*lp
)
2373 struct cleanup
*old_chain
;
2375 if (linux_ops
->to_stopped_by_watchpoint
== NULL
)
2378 old_chain
= save_inferior_ptid ();
2379 inferior_ptid
= lp
->ptid
;
2381 if (linux_ops
->to_stopped_by_watchpoint (linux_ops
))
2383 lp
->stop_reason
= LWP_STOPPED_BY_WATCHPOINT
;
2385 if (linux_ops
->to_stopped_data_address
!= NULL
)
2386 lp
->stopped_data_address_p
=
2387 linux_ops
->to_stopped_data_address (¤t_target
,
2388 &lp
->stopped_data_address
);
2390 lp
->stopped_data_address_p
= 0;
2393 do_cleanups (old_chain
);
2395 return lp
->stop_reason
== LWP_STOPPED_BY_WATCHPOINT
;
2398 /* Called when the LWP stopped for a trap that could be explained by a
2399 watchpoint or a breakpoint. */
2402 save_sigtrap (struct lwp_info
*lp
)
2404 gdb_assert (lp
->stop_reason
== LWP_STOPPED_BY_NO_REASON
);
2405 gdb_assert (lp
->status
!= 0);
2407 if (check_stopped_by_watchpoint (lp
))
2410 if (linux_nat_status_is_event (lp
->status
))
2411 check_stopped_by_breakpoint (lp
);
2414 /* Returns true if the LWP had stopped for a watchpoint. */
2417 linux_nat_stopped_by_watchpoint (struct target_ops
*ops
)
2419 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2421 gdb_assert (lp
!= NULL
);
2423 return lp
->stop_reason
== LWP_STOPPED_BY_WATCHPOINT
;
2427 linux_nat_stopped_data_address (struct target_ops
*ops
, CORE_ADDR
*addr_p
)
2429 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2431 gdb_assert (lp
!= NULL
);
2433 *addr_p
= lp
->stopped_data_address
;
2435 return lp
->stopped_data_address_p
;
2438 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2441 sigtrap_is_event (int status
)
2443 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2446 /* Set alternative SIGTRAP-like events recognizer. If
2447 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2451 linux_nat_set_status_is_event (struct target_ops
*t
,
2452 int (*status_is_event
) (int status
))
2454 linux_nat_status_is_event
= status_is_event
;
2457 /* Wait until LP is stopped. */
2460 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2462 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
2464 /* If this is a vfork parent, bail out, it is not going to report
2465 any SIGSTOP until the vfork is done with. */
2466 if (inf
->vfork_child
!= NULL
)
2473 status
= wait_lwp (lp
);
2477 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2478 && WSTOPSIG (status
) == SIGINT
)
2480 lp
->ignore_sigint
= 0;
2483 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2485 if (debug_linux_nat
)
2486 fprintf_unfiltered (gdb_stdlog
,
2487 "PTRACE_CONT %s, 0, 0 (%s) "
2488 "(discarding SIGINT)\n",
2489 target_pid_to_str (lp
->ptid
),
2490 errno
? safe_strerror (errno
) : "OK");
2492 return stop_wait_callback (lp
, NULL
);
2495 maybe_clear_ignore_sigint (lp
);
2497 if (WSTOPSIG (status
) != SIGSTOP
)
2499 /* The thread was stopped with a signal other than SIGSTOP. */
2501 if (debug_linux_nat
)
2502 fprintf_unfiltered (gdb_stdlog
,
2503 "SWC: Pending event %s in %s\n",
2504 status_to_str ((int) status
),
2505 target_pid_to_str (lp
->ptid
));
2507 /* Save the sigtrap event. */
2508 lp
->status
= status
;
2509 gdb_assert (lp
->signalled
);
2514 /* We caught the SIGSTOP that we intended to catch, so
2515 there's no SIGSTOP pending. */
2517 if (debug_linux_nat
)
2518 fprintf_unfiltered (gdb_stdlog
,
2519 "SWC: Delayed SIGSTOP caught for %s.\n",
2520 target_pid_to_str (lp
->ptid
));
2522 /* Reset SIGNALLED only after the stop_wait_callback call
2523 above as it does gdb_assert on SIGNALLED. */
2531 /* Return non-zero if LP has a wait status pending. Discard the
2532 pending event and resume the LWP if the event that originally
2533 caused the stop became uninteresting. */
2536 status_callback (struct lwp_info
*lp
, void *data
)
2538 /* Only report a pending wait status if we pretend that this has
2539 indeed been resumed. */
2543 if (lp
->stop_reason
== LWP_STOPPED_BY_SW_BREAKPOINT
2544 || lp
->stop_reason
== LWP_STOPPED_BY_HW_BREAKPOINT
)
2546 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2547 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2551 gdb_assert (lp
->status
!= 0);
2553 pc
= regcache_read_pc (regcache
);
2555 if (pc
!= lp
->stop_pc
)
2557 if (debug_linux_nat
)
2558 fprintf_unfiltered (gdb_stdlog
,
2559 "SC: PC of %s changed. was=%s, now=%s\n",
2560 target_pid_to_str (lp
->ptid
),
2561 paddress (target_gdbarch (), lp
->stop_pc
),
2562 paddress (target_gdbarch (), pc
));
2565 else if (!breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2567 if (debug_linux_nat
)
2568 fprintf_unfiltered (gdb_stdlog
,
2569 "SC: previous breakpoint of %s, at %s gone\n",
2570 target_pid_to_str (lp
->ptid
),
2571 paddress (target_gdbarch (), lp
->stop_pc
));
2578 if (debug_linux_nat
)
2579 fprintf_unfiltered (gdb_stdlog
,
2580 "SC: pending event of %s cancelled.\n",
2581 target_pid_to_str (lp
->ptid
));
2584 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2590 return lwp_status_pending_p (lp
);
2593 /* Return non-zero if LP isn't stopped. */
2596 running_callback (struct lwp_info
*lp
, void *data
)
2598 return (!lp
->stopped
2599 || (lwp_status_pending_p (lp
) && lp
->resumed
));
2602 /* Count the LWP's that have had events. */
2605 count_events_callback (struct lwp_info
*lp
, void *data
)
2609 gdb_assert (count
!= NULL
);
2611 /* Select only resumed LWPs that have an event pending. */
2612 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2618 /* Select the LWP (if any) that is currently being single-stepped. */
2621 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2623 if (lp
->last_resume_kind
== resume_step
2630 /* Returns true if LP has a status pending. */
2633 lwp_status_pending_p (struct lwp_info
*lp
)
2635 /* We check for lp->waitstatus in addition to lp->status, because we
2636 can have pending process exits recorded in lp->status and
2637 W_EXITCODE(0,0) happens to be 0. */
2638 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2641 /* Select the Nth LWP that has had a SIGTRAP event. */
2644 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2646 int *selector
= data
;
2648 gdb_assert (selector
!= NULL
);
2650 /* Select only resumed LWPs that have an event pending. */
2651 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2652 if ((*selector
)-- == 0)
2658 /* Called when the LWP got a signal/trap that could be explained by a
2659 software or hardware breakpoint. */
2662 check_stopped_by_breakpoint (struct lwp_info
*lp
)
2664 /* Arrange for a breakpoint to be hit again later. We don't keep
2665 the SIGTRAP status and don't forward the SIGTRAP signal to the
2666 LWP. We will handle the current event, eventually we will resume
2667 this LWP, and this breakpoint will trap again.
2669 If we do not do this, then we run the risk that the user will
2670 delete or disable the breakpoint, but the LWP will have already
2673 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2674 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2678 pc
= regcache_read_pc (regcache
);
2679 sw_bp_pc
= pc
- target_decr_pc_after_break (gdbarch
);
2681 if ((!lp
->step
|| lp
->stop_pc
== sw_bp_pc
)
2682 && software_breakpoint_inserted_here_p (get_regcache_aspace (regcache
),
2685 /* The LWP was either continued, or stepped a software
2686 breakpoint instruction. */
2687 if (debug_linux_nat
)
2688 fprintf_unfiltered (gdb_stdlog
,
2689 "CB: Push back software breakpoint for %s\n",
2690 target_pid_to_str (lp
->ptid
));
2692 /* Back up the PC if necessary. */
2694 regcache_write_pc (regcache
, sw_bp_pc
);
2696 lp
->stop_pc
= sw_bp_pc
;
2697 lp
->stop_reason
= LWP_STOPPED_BY_SW_BREAKPOINT
;
2701 if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2703 if (debug_linux_nat
)
2704 fprintf_unfiltered (gdb_stdlog
,
2705 "CB: Push back hardware breakpoint for %s\n",
2706 target_pid_to_str (lp
->ptid
));
2709 lp
->stop_reason
= LWP_STOPPED_BY_HW_BREAKPOINT
;
2716 /* Select one LWP out of those that have events pending. */
2719 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2722 int random_selector
;
2723 struct lwp_info
*event_lp
= NULL
;
2725 /* Record the wait status for the original LWP. */
2726 (*orig_lp
)->status
= *status
;
2728 /* In all-stop, give preference to the LWP that is being
2729 single-stepped. There will be at most one, and it will be the
2730 LWP that the core is most interested in. If we didn't do this,
2731 then we'd have to handle pending step SIGTRAPs somehow in case
2732 the core later continues the previously-stepped thread, as
2733 otherwise we'd report the pending SIGTRAP then, and the core, not
2734 having stepped the thread, wouldn't understand what the trap was
2735 for, and therefore would report it to the user as a random
2739 event_lp
= iterate_over_lwps (filter
,
2740 select_singlestep_lwp_callback
, NULL
);
2741 if (event_lp
!= NULL
)
2743 if (debug_linux_nat
)
2744 fprintf_unfiltered (gdb_stdlog
,
2745 "SEL: Select single-step %s\n",
2746 target_pid_to_str (event_lp
->ptid
));
2750 if (event_lp
== NULL
)
2752 /* Pick one at random, out of those which have had events. */
2754 /* First see how many events we have. */
2755 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2757 /* Now randomly pick a LWP out of those that have had
2759 random_selector
= (int)
2760 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2762 if (debug_linux_nat
&& num_events
> 1)
2763 fprintf_unfiltered (gdb_stdlog
,
2764 "SEL: Found %d events, selecting #%d\n",
2765 num_events
, random_selector
);
2767 event_lp
= iterate_over_lwps (filter
,
2768 select_event_lwp_callback
,
2772 if (event_lp
!= NULL
)
2774 /* Switch the event LWP. */
2775 *orig_lp
= event_lp
;
2776 *status
= event_lp
->status
;
2779 /* Flush the wait status for the event LWP. */
2780 (*orig_lp
)->status
= 0;
2783 /* Return non-zero if LP has been resumed. */
2786 resumed_callback (struct lwp_info
*lp
, void *data
)
2791 /* Stop an active thread, verify it still exists, then resume it. If
2792 the thread ends up with a pending status, then it is not resumed,
2793 and *DATA (really a pointer to int), is set. */
2796 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2800 ptid_t ptid
= lp
->ptid
;
2802 stop_callback (lp
, NULL
);
2803 stop_wait_callback (lp
, NULL
);
2805 /* Resume if the lwp still exists, and the core wanted it
2807 lp
= find_lwp_pid (ptid
);
2810 if (lp
->last_resume_kind
== resume_stop
2811 && !lwp_status_pending_p (lp
))
2813 /* The core wanted the LWP to stop. Even if it stopped
2814 cleanly (with SIGSTOP), leave the event pending. */
2815 if (debug_linux_nat
)
2816 fprintf_unfiltered (gdb_stdlog
,
2817 "SARC: core wanted LWP %ld stopped "
2818 "(leaving SIGSTOP pending)\n",
2819 ptid_get_lwp (lp
->ptid
));
2820 lp
->status
= W_STOPCODE (SIGSTOP
);
2823 if (!lwp_status_pending_p (lp
))
2825 if (debug_linux_nat
)
2826 fprintf_unfiltered (gdb_stdlog
,
2827 "SARC: re-resuming LWP %ld\n",
2828 ptid_get_lwp (lp
->ptid
));
2829 resume_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2833 if (debug_linux_nat
)
2834 fprintf_unfiltered (gdb_stdlog
,
2835 "SARC: not re-resuming LWP %ld "
2837 ptid_get_lwp (lp
->ptid
));
2844 /* Check if we should go on and pass this event to common code.
2845 Return the affected lwp if we are, or NULL otherwise. */
2847 static struct lwp_info
*
2848 linux_nat_filter_event (int lwpid
, int status
)
2850 struct lwp_info
*lp
;
2851 int event
= linux_ptrace_get_extended_event (status
);
2853 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2855 /* Check for stop events reported by a process we didn't already
2856 know about - anything not already in our LWP list.
2858 If we're expecting to receive stopped processes after
2859 fork, vfork, and clone events, then we'll just add the
2860 new one to our list and go back to waiting for the event
2861 to be reported - the stopped process might be returned
2862 from waitpid before or after the event is.
2864 But note the case of a non-leader thread exec'ing after the
2865 leader having exited, and gone from our lists. The non-leader
2866 thread changes its tid to the tgid. */
2868 if (WIFSTOPPED (status
) && lp
== NULL
2869 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2871 /* A multi-thread exec after we had seen the leader exiting. */
2872 if (debug_linux_nat
)
2873 fprintf_unfiltered (gdb_stdlog
,
2874 "LLW: Re-adding thread group leader LWP %d.\n",
2877 lp
= add_lwp (ptid_build (lwpid
, lwpid
, 0));
2880 add_thread (lp
->ptid
);
2883 if (WIFSTOPPED (status
) && !lp
)
2885 if (debug_linux_nat
)
2886 fprintf_unfiltered (gdb_stdlog
,
2887 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2888 (long) lwpid
, status_to_str (status
));
2889 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2893 /* Make sure we don't report an event for the exit of an LWP not in
2894 our list, i.e. not part of the current process. This can happen
2895 if we detach from a program we originally forked and then it
2897 if (!WIFSTOPPED (status
) && !lp
)
2900 /* This LWP is stopped now. (And if dead, this prevents it from
2901 ever being continued.) */
2904 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2906 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2908 linux_enable_event_reporting (ptid_get_lwp (lp
->ptid
), inf
->attach_flag
);
2909 lp
->must_set_ptrace_flags
= 0;
2912 /* Handle GNU/Linux's syscall SIGTRAPs. */
2913 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2915 /* No longer need the sysgood bit. The ptrace event ends up
2916 recorded in lp->waitstatus if we care for it. We can carry
2917 on handling the event like a regular SIGTRAP from here
2919 status
= W_STOPCODE (SIGTRAP
);
2920 if (linux_handle_syscall_trap (lp
, 0))
2924 /* Handle GNU/Linux's extended waitstatus for trace events. */
2925 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2926 && linux_is_extended_waitstatus (status
))
2928 if (debug_linux_nat
)
2929 fprintf_unfiltered (gdb_stdlog
,
2930 "LLW: Handling extended status 0x%06x\n",
2932 if (linux_handle_extended_wait (lp
, status
, 0))
2936 /* Check if the thread has exited. */
2937 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2939 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2941 /* If this is the main thread, we must stop all threads and
2942 verify if they are still alive. This is because in the
2943 nptl thread model on Linux 2.4, there is no signal issued
2944 for exiting LWPs other than the main thread. We only get
2945 the main thread exit signal once all child threads have
2946 already exited. If we stop all the threads and use the
2947 stop_wait_callback to check if they have exited we can
2948 determine whether this signal should be ignored or
2949 whether it means the end of the debugged application,
2950 regardless of which threading model is being used. */
2951 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
))
2953 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
2954 stop_and_resume_callback
, NULL
);
2957 if (debug_linux_nat
)
2958 fprintf_unfiltered (gdb_stdlog
,
2959 "LLW: %s exited.\n",
2960 target_pid_to_str (lp
->ptid
));
2962 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2964 /* If there is at least one more LWP, then the exit signal
2965 was not the end of the debugged application and should be
2972 gdb_assert (lp
->resumed
);
2974 if (debug_linux_nat
)
2975 fprintf_unfiltered (gdb_stdlog
,
2976 "Process %ld exited\n",
2977 ptid_get_lwp (lp
->ptid
));
2979 /* This was the last lwp in the process. Since events are
2980 serialized to GDB core, we may not be able report this one
2981 right now, but GDB core and the other target layers will want
2982 to be notified about the exit code/signal, leave the status
2983 pending for the next time we're able to report it. */
2985 /* Dead LWP's aren't expected to reported a pending sigstop. */
2988 /* Store the pending event in the waitstatus, because
2989 W_EXITCODE(0,0) == 0. */
2990 store_waitstatus (&lp
->waitstatus
, status
);
2994 /* Check if the current LWP has previously exited. In the nptl
2995 thread model, LWPs other than the main thread do not issue
2996 signals when they exit so we must check whenever the thread has
2997 stopped. A similar check is made in stop_wait_callback(). */
2998 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1 && !linux_thread_alive (lp
->ptid
))
3000 ptid_t ptid
= pid_to_ptid (ptid_get_pid (lp
->ptid
));
3002 if (debug_linux_nat
)
3003 fprintf_unfiltered (gdb_stdlog
,
3004 "LLW: %s exited.\n",
3005 target_pid_to_str (lp
->ptid
));
3009 /* Make sure there is at least one thread running. */
3010 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
3012 /* Discard the event. */
3016 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3017 an attempt to stop an LWP. */
3019 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3021 if (debug_linux_nat
)
3022 fprintf_unfiltered (gdb_stdlog
,
3023 "LLW: Delayed SIGSTOP caught for %s.\n",
3024 target_pid_to_str (lp
->ptid
));
3028 if (lp
->last_resume_kind
!= resume_stop
)
3030 /* This is a delayed SIGSTOP. */
3032 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3033 if (debug_linux_nat
)
3034 fprintf_unfiltered (gdb_stdlog
,
3035 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3037 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3038 target_pid_to_str (lp
->ptid
));
3040 gdb_assert (lp
->resumed
);
3042 /* Discard the event. */
3047 /* Make sure we don't report a SIGINT that we have already displayed
3048 for another thread. */
3049 if (lp
->ignore_sigint
3050 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3052 if (debug_linux_nat
)
3053 fprintf_unfiltered (gdb_stdlog
,
3054 "LLW: Delayed SIGINT caught for %s.\n",
3055 target_pid_to_str (lp
->ptid
));
3057 /* This is a delayed SIGINT. */
3058 lp
->ignore_sigint
= 0;
3060 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3061 if (debug_linux_nat
)
3062 fprintf_unfiltered (gdb_stdlog
,
3063 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3065 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3066 target_pid_to_str (lp
->ptid
));
3067 gdb_assert (lp
->resumed
);
3069 /* Discard the event. */
3073 /* Don't report signals that GDB isn't interested in, such as
3074 signals that are neither printed nor stopped upon. Stopping all
3075 threads can be a bit time-consuming so if we want decent
3076 performance with heavily multi-threaded programs, especially when
3077 they're using a high frequency timer, we'd better avoid it if we
3079 if (WIFSTOPPED (status
))
3081 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3085 /* Only do the below in all-stop, as we currently use SIGSTOP
3086 to implement target_stop (see linux_nat_stop) in
3088 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3090 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3091 forwarded to the entire process group, that is, all LWPs
3092 will receive it - unless they're using CLONE_THREAD to
3093 share signals. Since we only want to report it once, we
3094 mark it as ignored for all LWPs except this one. */
3095 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
3096 set_ignore_sigint
, NULL
);
3097 lp
->ignore_sigint
= 0;
3100 maybe_clear_ignore_sigint (lp
);
3103 /* When using hardware single-step, we need to report every signal.
3104 Otherwise, signals in pass_mask may be short-circuited
3105 except signals that might be caused by a breakpoint. */
3107 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
))
3108 && !linux_wstatus_maybe_breakpoint (status
))
3110 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3111 if (debug_linux_nat
)
3112 fprintf_unfiltered (gdb_stdlog
,
3113 "LLW: %s %s, %s (preempt 'handle')\n",
3115 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3116 target_pid_to_str (lp
->ptid
),
3117 (signo
!= GDB_SIGNAL_0
3118 ? strsignal (gdb_signal_to_host (signo
))
3124 /* An interesting event. */
3126 lp
->status
= status
;
3131 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3132 their exits until all other threads in the group have exited. */
3135 check_zombie_leaders (void)
3137 struct inferior
*inf
;
3141 struct lwp_info
*leader_lp
;
3146 leader_lp
= find_lwp_pid (pid_to_ptid (inf
->pid
));
3147 if (leader_lp
!= NULL
3148 /* Check if there are other threads in the group, as we may
3149 have raced with the inferior simply exiting. */
3150 && num_lwps (inf
->pid
) > 1
3151 && linux_proc_pid_is_zombie (inf
->pid
))
3153 if (debug_linux_nat
)
3154 fprintf_unfiltered (gdb_stdlog
,
3155 "CZL: Thread group leader %d zombie "
3156 "(it exited, or another thread execd).\n",
3159 /* A leader zombie can mean one of two things:
3161 - It exited, and there's an exit status pending
3162 available, or only the leader exited (not the whole
3163 program). In the latter case, we can't waitpid the
3164 leader's exit status until all other threads are gone.
3166 - There are 3 or more threads in the group, and a thread
3167 other than the leader exec'd. On an exec, the Linux
3168 kernel destroys all other threads (except the execing
3169 one) in the thread group, and resets the execing thread's
3170 tid to the tgid. No exit notification is sent for the
3171 execing thread -- from the ptracer's perspective, it
3172 appears as though the execing thread just vanishes.
3173 Until we reap all other threads except the leader and the
3174 execing thread, the leader will be zombie, and the
3175 execing thread will be in `D (disc sleep)'. As soon as
3176 all other threads are reaped, the execing thread changes
3177 it's tid to the tgid, and the previous (zombie) leader
3178 vanishes, giving place to the "new" leader. We could try
3179 distinguishing the exit and exec cases, by waiting once
3180 more, and seeing if something comes out, but it doesn't
3181 sound useful. The previous leader _does_ go away, and
3182 we'll re-add the new one once we see the exec event
3183 (which is just the same as what would happen if the
3184 previous leader did exit voluntarily before some other
3187 if (debug_linux_nat
)
3188 fprintf_unfiltered (gdb_stdlog
,
3189 "CZL: Thread group leader %d vanished.\n",
3191 exit_lwp (leader_lp
);
3197 linux_nat_wait_1 (struct target_ops
*ops
,
3198 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3202 enum resume_kind last_resume_kind
;
3203 struct lwp_info
*lp
;
3206 if (debug_linux_nat
)
3207 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3209 /* The first time we get here after starting a new inferior, we may
3210 not have added it to the LWP list yet - this is the earliest
3211 moment at which we know its PID. */
3212 if (ptid_is_pid (inferior_ptid
))
3214 /* Upgrade the main thread's ptid. */
3215 thread_change_ptid (inferior_ptid
,
3216 ptid_build (ptid_get_pid (inferior_ptid
),
3217 ptid_get_pid (inferior_ptid
), 0));
3219 lp
= add_initial_lwp (inferior_ptid
);
3223 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3224 block_child_signals (&prev_mask
);
3226 /* First check if there is a LWP with a wait status pending. */
3227 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3230 if (debug_linux_nat
)
3231 fprintf_unfiltered (gdb_stdlog
,
3232 "LLW: Using pending wait status %s for %s.\n",
3233 status_to_str (lp
->status
),
3234 target_pid_to_str (lp
->ptid
));
3237 if (!target_is_async_p ())
3239 /* Causes SIGINT to be passed on to the attached process. */
3243 /* But if we don't find a pending event, we'll have to wait. Always
3244 pull all events out of the kernel. We'll randomly select an
3245 event LWP out of all that have events, to prevent starvation. */
3251 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3254 - If the thread group leader exits while other threads in the
3255 thread group still exist, waitpid(TGID, ...) hangs. That
3256 waitpid won't return an exit status until the other threads
3257 in the group are reapped.
3259 - When a non-leader thread execs, that thread just vanishes
3260 without reporting an exit (so we'd hang if we waited for it
3261 explicitly in that case). The exec event is reported to
3265 lwpid
= my_waitpid (-1, &status
, __WCLONE
| WNOHANG
);
3266 if (lwpid
== 0 || (lwpid
== -1 && errno
== ECHILD
))
3267 lwpid
= my_waitpid (-1, &status
, WNOHANG
);
3269 if (debug_linux_nat
)
3270 fprintf_unfiltered (gdb_stdlog
,
3271 "LNW: waitpid(-1, ...) returned %d, %s\n",
3272 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3276 if (debug_linux_nat
)
3278 fprintf_unfiltered (gdb_stdlog
,
3279 "LLW: waitpid %ld received %s\n",
3280 (long) lwpid
, status_to_str (status
));
3283 linux_nat_filter_event (lwpid
, status
);
3284 /* Retry until nothing comes out of waitpid. A single
3285 SIGCHLD can indicate more than one child stopped. */
3289 /* Now that we've pulled all events out of the kernel, resume
3290 LWPs that don't have an interesting event to report. */
3291 iterate_over_lwps (minus_one_ptid
,
3292 resume_stopped_resumed_lwps
, &minus_one_ptid
);
3294 /* ... and find an LWP with a status to report to the core, if
3296 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3300 /* Check for zombie thread group leaders. Those can't be reaped
3301 until all other threads in the thread group are. */
3302 check_zombie_leaders ();
3304 /* If there are no resumed children left, bail. We'd be stuck
3305 forever in the sigsuspend call below otherwise. */
3306 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3308 if (debug_linux_nat
)
3309 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3311 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3313 if (!target_is_async_p ())
3314 clear_sigint_trap ();
3316 restore_child_signals_mask (&prev_mask
);
3317 return minus_one_ptid
;
3320 /* No interesting event to report to the core. */
3322 if (target_options
& TARGET_WNOHANG
)
3324 if (debug_linux_nat
)
3325 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3327 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3328 restore_child_signals_mask (&prev_mask
);
3329 return minus_one_ptid
;
3332 /* We shouldn't end up here unless we want to try again. */
3333 gdb_assert (lp
== NULL
);
3335 /* Block until we get an event reported with SIGCHLD. */
3336 if (debug_linux_nat
)
3337 fprintf_unfiltered (gdb_stdlog
, "LNW: about to sigsuspend\n");
3338 sigsuspend (&suspend_mask
);
3341 if (!target_is_async_p ())
3342 clear_sigint_trap ();
3346 status
= lp
->status
;
3351 /* Now stop all other LWP's ... */
3352 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3354 /* ... and wait until all of them have reported back that
3355 they're no longer running. */
3356 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3359 /* If we're not waiting for a specific LWP, choose an event LWP from
3360 among those that have had events. Giving equal priority to all
3361 LWPs that have had events helps prevent starvation. */
3362 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3363 select_event_lwp (ptid
, &lp
, &status
);
3365 gdb_assert (lp
!= NULL
);
3367 /* Now that we've selected our final event LWP, un-adjust its PC if
3368 it was a software breakpoint. */
3369 if (lp
->stop_reason
== LWP_STOPPED_BY_SW_BREAKPOINT
)
3371 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3372 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3373 int decr_pc
= target_decr_pc_after_break (gdbarch
);
3379 pc
= regcache_read_pc (regcache
);
3380 regcache_write_pc (regcache
, pc
+ decr_pc
);
3384 /* We'll need this to determine whether to report a SIGSTOP as
3385 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3387 last_resume_kind
= lp
->last_resume_kind
;
3391 /* In all-stop, from the core's perspective, all LWPs are now
3392 stopped until a new resume action is sent over. */
3393 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3397 resume_clear_callback (lp
, NULL
);
3400 if (linux_nat_status_is_event (status
))
3402 if (debug_linux_nat
)
3403 fprintf_unfiltered (gdb_stdlog
,
3404 "LLW: trap ptid is %s.\n",
3405 target_pid_to_str (lp
->ptid
));
3408 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3410 *ourstatus
= lp
->waitstatus
;
3411 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3414 store_waitstatus (ourstatus
, status
);
3416 if (debug_linux_nat
)
3417 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3419 restore_child_signals_mask (&prev_mask
);
3421 if (last_resume_kind
== resume_stop
3422 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3423 && WSTOPSIG (status
) == SIGSTOP
)
3425 /* A thread that has been requested to stop by GDB with
3426 target_stop, and it stopped cleanly, so report as SIG0. The
3427 use of SIGSTOP is an implementation detail. */
3428 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3431 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3432 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3435 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3440 /* Resume LWPs that are currently stopped without any pending status
3441 to report, but are resumed from the core's perspective. */
3444 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3446 ptid_t
*wait_ptid_p
= data
;
3450 && !lwp_status_pending_p (lp
))
3452 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3453 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3454 CORE_ADDR pc
= regcache_read_pc (regcache
);
3456 /* Don't bother if there's a breakpoint at PC that we'd hit
3457 immediately, and we're not waiting for this LWP. */
3458 if (!ptid_match (lp
->ptid
, *wait_ptid_p
))
3460 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
3464 if (debug_linux_nat
)
3465 fprintf_unfiltered (gdb_stdlog
,
3466 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3467 target_pid_to_str (lp
->ptid
),
3468 paddress (gdbarch
, pc
),
3471 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3478 linux_nat_wait (struct target_ops
*ops
,
3479 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3484 if (debug_linux_nat
)
3486 char *options_string
;
3488 options_string
= target_options_to_string (target_options
);
3489 fprintf_unfiltered (gdb_stdlog
,
3490 "linux_nat_wait: [%s], [%s]\n",
3491 target_pid_to_str (ptid
),
3493 xfree (options_string
);
3496 /* Flush the async file first. */
3497 if (target_is_async_p ())
3498 async_file_flush ();
3500 /* Resume LWPs that are currently stopped without any pending status
3501 to report, but are resumed from the core's perspective. LWPs get
3502 in this state if we find them stopping at a time we're not
3503 interested in reporting the event (target_wait on a
3504 specific_process, for example, see linux_nat_wait_1), and
3505 meanwhile the event became uninteresting. Don't bother resuming
3506 LWPs we're not going to wait for if they'd stop immediately. */
3508 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3510 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
3512 /* If we requested any event, and something came out, assume there
3513 may be more. If we requested a specific lwp or process, also
3514 assume there may be more. */
3515 if (target_is_async_p ()
3516 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3517 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3518 || !ptid_equal (ptid
, minus_one_ptid
)))
3525 kill_callback (struct lwp_info
*lp
, void *data
)
3527 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3530 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGKILL
);
3531 if (debug_linux_nat
)
3533 int save_errno
= errno
;
3535 fprintf_unfiltered (gdb_stdlog
,
3536 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3537 target_pid_to_str (lp
->ptid
),
3538 save_errno
? safe_strerror (save_errno
) : "OK");
3541 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3544 ptrace (PTRACE_KILL
, ptid_get_lwp (lp
->ptid
), 0, 0);
3545 if (debug_linux_nat
)
3547 int save_errno
= errno
;
3549 fprintf_unfiltered (gdb_stdlog
,
3550 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3551 target_pid_to_str (lp
->ptid
),
3552 save_errno
? safe_strerror (save_errno
) : "OK");
3559 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3563 /* We must make sure that there are no pending events (delayed
3564 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3565 program doesn't interfere with any following debugging session. */
3567 /* For cloned processes we must check both with __WCLONE and
3568 without, since the exit status of a cloned process isn't reported
3574 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, __WCLONE
);
3575 if (pid
!= (pid_t
) -1)
3577 if (debug_linux_nat
)
3578 fprintf_unfiltered (gdb_stdlog
,
3579 "KWC: wait %s received unknown.\n",
3580 target_pid_to_str (lp
->ptid
));
3581 /* The Linux kernel sometimes fails to kill a thread
3582 completely after PTRACE_KILL; that goes from the stop
3583 point in do_fork out to the one in
3584 get_signal_to_deliever and waits again. So kill it
3586 kill_callback (lp
, NULL
);
3589 while (pid
== ptid_get_lwp (lp
->ptid
));
3591 gdb_assert (pid
== -1 && errno
== ECHILD
);
3596 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, 0);
3597 if (pid
!= (pid_t
) -1)
3599 if (debug_linux_nat
)
3600 fprintf_unfiltered (gdb_stdlog
,
3601 "KWC: wait %s received unk.\n",
3602 target_pid_to_str (lp
->ptid
));
3603 /* See the call to kill_callback above. */
3604 kill_callback (lp
, NULL
);
3607 while (pid
== ptid_get_lwp (lp
->ptid
));
3609 gdb_assert (pid
== -1 && errno
== ECHILD
);
3614 linux_nat_kill (struct target_ops
*ops
)
3616 struct target_waitstatus last
;
3620 /* If we're stopped while forking and we haven't followed yet,
3621 kill the other task. We need to do this first because the
3622 parent will be sleeping if this is a vfork. */
3624 get_last_target_status (&last_ptid
, &last
);
3626 if (last
.kind
== TARGET_WAITKIND_FORKED
3627 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3629 ptrace (PT_KILL
, ptid_get_pid (last
.value
.related_pid
), 0, 0);
3632 /* Let the arch-specific native code know this process is
3634 linux_nat_forget_process (ptid_get_pid (last
.value
.related_pid
));
3637 if (forks_exist_p ())
3638 linux_fork_killall ();
3641 ptid_t ptid
= pid_to_ptid (ptid_get_pid (inferior_ptid
));
3643 /* Stop all threads before killing them, since ptrace requires
3644 that the thread is stopped to sucessfully PTRACE_KILL. */
3645 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3646 /* ... and wait until all of them have reported back that
3647 they're no longer running. */
3648 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3650 /* Kill all LWP's ... */
3651 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3653 /* ... and wait until we've flushed all events. */
3654 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3657 target_mourn_inferior ();
3661 linux_nat_mourn_inferior (struct target_ops
*ops
)
3663 int pid
= ptid_get_pid (inferior_ptid
);
3665 purge_lwp_list (pid
);
3667 if (! forks_exist_p ())
3668 /* Normal case, no other forks available. */
3669 linux_ops
->to_mourn_inferior (ops
);
3671 /* Multi-fork case. The current inferior_ptid has exited, but
3672 there are other viable forks to debug. Delete the exiting
3673 one and context-switch to the first available. */
3674 linux_fork_mourn_inferior ();
3676 /* Let the arch-specific native code know this process is gone. */
3677 linux_nat_forget_process (pid
);
3680 /* Convert a native/host siginfo object, into/from the siginfo in the
3681 layout of the inferiors' architecture. */
3684 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3688 if (linux_nat_siginfo_fixup
!= NULL
)
3689 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3691 /* If there was no callback, or the callback didn't do anything,
3692 then just do a straight memcpy. */
3696 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3698 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3702 static enum target_xfer_status
3703 linux_xfer_siginfo (struct target_ops
*ops
, enum target_object object
,
3704 const char *annex
, gdb_byte
*readbuf
,
3705 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3706 ULONGEST
*xfered_len
)
3710 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3712 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3713 gdb_assert (readbuf
|| writebuf
);
3715 pid
= ptid_get_lwp (inferior_ptid
);
3717 pid
= ptid_get_pid (inferior_ptid
);
3719 if (offset
> sizeof (siginfo
))
3720 return TARGET_XFER_E_IO
;
3723 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3725 return TARGET_XFER_E_IO
;
3727 /* When GDB is built as a 64-bit application, ptrace writes into
3728 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3729 inferior with a 64-bit GDB should look the same as debugging it
3730 with a 32-bit GDB, we need to convert it. GDB core always sees
3731 the converted layout, so any read/write will have to be done
3733 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3735 if (offset
+ len
> sizeof (siginfo
))
3736 len
= sizeof (siginfo
) - offset
;
3738 if (readbuf
!= NULL
)
3739 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3742 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3744 /* Convert back to ptrace layout before flushing it out. */
3745 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3748 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3750 return TARGET_XFER_E_IO
;
3754 return TARGET_XFER_OK
;
3757 static enum target_xfer_status
3758 linux_nat_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3759 const char *annex
, gdb_byte
*readbuf
,
3760 const gdb_byte
*writebuf
,
3761 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3763 struct cleanup
*old_chain
;
3764 enum target_xfer_status xfer
;
3766 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3767 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3768 offset
, len
, xfered_len
);
3770 /* The target is connected but no live inferior is selected. Pass
3771 this request down to a lower stratum (e.g., the executable
3773 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3774 return TARGET_XFER_EOF
;
3776 old_chain
= save_inferior_ptid ();
3778 if (ptid_lwp_p (inferior_ptid
))
3779 inferior_ptid
= pid_to_ptid (ptid_get_lwp (inferior_ptid
));
3781 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3782 offset
, len
, xfered_len
);
3784 do_cleanups (old_chain
);
3789 linux_thread_alive (ptid_t ptid
)
3793 gdb_assert (ptid_lwp_p (ptid
));
3795 /* Send signal 0 instead of anything ptrace, because ptracing a
3796 running thread errors out claiming that the thread doesn't
3798 err
= kill_lwp (ptid_get_lwp (ptid
), 0);
3800 if (debug_linux_nat
)
3801 fprintf_unfiltered (gdb_stdlog
,
3802 "LLTA: KILL(SIG0) %s (%s)\n",
3803 target_pid_to_str (ptid
),
3804 err
? safe_strerror (tmp_errno
) : "OK");
3813 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3815 return linux_thread_alive (ptid
);
3819 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3821 static char buf
[64];
3823 if (ptid_lwp_p (ptid
)
3824 && (ptid_get_pid (ptid
) != ptid_get_lwp (ptid
)
3825 || num_lwps (ptid_get_pid (ptid
)) > 1))
3827 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid_get_lwp (ptid
));
3831 return normal_pid_to_str (ptid
);
3835 linux_nat_thread_name (struct target_ops
*self
, struct thread_info
*thr
)
3837 int pid
= ptid_get_pid (thr
->ptid
);
3838 long lwp
= ptid_get_lwp (thr
->ptid
);
3839 #define FORMAT "/proc/%d/task/%ld/comm"
3840 char buf
[sizeof (FORMAT
) + 30];
3842 char *result
= NULL
;
3844 snprintf (buf
, sizeof (buf
), FORMAT
, pid
, lwp
);
3845 comm_file
= gdb_fopen_cloexec (buf
, "r");
3848 /* Not exported by the kernel, so we define it here. */
3850 static char line
[COMM_LEN
+ 1];
3852 if (fgets (line
, sizeof (line
), comm_file
))
3854 char *nl
= strchr (line
, '\n');
3871 /* Accepts an integer PID; Returns a string representing a file that
3872 can be opened to get the symbols for the child process. */
3875 linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
)
3877 static char buf
[PATH_MAX
];
3878 char name
[PATH_MAX
];
3880 xsnprintf (name
, PATH_MAX
, "/proc/%d/exe", pid
);
3881 memset (buf
, 0, PATH_MAX
);
3882 if (readlink (name
, buf
, PATH_MAX
- 1) <= 0)
3888 /* Implement the to_xfer_partial interface for memory reads using the /proc
3889 filesystem. Because we can use a single read() call for /proc, this
3890 can be much more efficient than banging away at PTRACE_PEEKTEXT,
3891 but it doesn't support writes. */
3893 static enum target_xfer_status
3894 linux_proc_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3895 const char *annex
, gdb_byte
*readbuf
,
3896 const gdb_byte
*writebuf
,
3897 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3903 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
3906 /* Don't bother for one word. */
3907 if (len
< 3 * sizeof (long))
3908 return TARGET_XFER_EOF
;
3910 /* We could keep this file open and cache it - possibly one per
3911 thread. That requires some juggling, but is even faster. */
3912 xsnprintf (filename
, sizeof filename
, "/proc/%d/mem",
3913 ptid_get_pid (inferior_ptid
));
3914 fd
= gdb_open_cloexec (filename
, O_RDONLY
| O_LARGEFILE
, 0);
3916 return TARGET_XFER_EOF
;
3918 /* If pread64 is available, use it. It's faster if the kernel
3919 supports it (only one syscall), and it's 64-bit safe even on
3920 32-bit platforms (for instance, SPARC debugging a SPARC64
3923 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
3925 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
3934 return TARGET_XFER_EOF
;
3938 return TARGET_XFER_OK
;
3943 /* Enumerate spufs IDs for process PID. */
3945 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
3947 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
3949 LONGEST written
= 0;
3952 struct dirent
*entry
;
3954 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
3955 dir
= opendir (path
);
3960 while ((entry
= readdir (dir
)) != NULL
)
3966 fd
= atoi (entry
->d_name
);
3970 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
3971 if (stat (path
, &st
) != 0)
3973 if (!S_ISDIR (st
.st_mode
))
3976 if (statfs (path
, &stfs
) != 0)
3978 if (stfs
.f_type
!= SPUFS_MAGIC
)
3981 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
3983 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
3993 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
3994 object type, using the /proc file system. */
3996 static enum target_xfer_status
3997 linux_proc_xfer_spu (struct target_ops
*ops
, enum target_object object
,
3998 const char *annex
, gdb_byte
*readbuf
,
3999 const gdb_byte
*writebuf
,
4000 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
4005 int pid
= ptid_get_pid (inferior_ptid
);
4010 return TARGET_XFER_E_IO
;
4013 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4016 return TARGET_XFER_E_IO
;
4018 return TARGET_XFER_EOF
;
4021 *xfered_len
= (ULONGEST
) l
;
4022 return TARGET_XFER_OK
;
4027 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4028 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4030 return TARGET_XFER_E_IO
;
4033 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4036 return TARGET_XFER_EOF
;
4040 ret
= write (fd
, writebuf
, (size_t) len
);
4042 ret
= read (fd
, readbuf
, (size_t) len
);
4047 return TARGET_XFER_E_IO
;
4049 return TARGET_XFER_EOF
;
4052 *xfered_len
= (ULONGEST
) ret
;
4053 return TARGET_XFER_OK
;
4058 /* Parse LINE as a signal set and add its set bits to SIGS. */
4061 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4063 int len
= strlen (line
) - 1;
4067 if (line
[len
] != '\n')
4068 error (_("Could not parse signal set: %s"), line
);
4076 if (*p
>= '0' && *p
<= '9')
4078 else if (*p
>= 'a' && *p
<= 'f')
4079 digit
= *p
- 'a' + 10;
4081 error (_("Could not parse signal set: %s"), line
);
4086 sigaddset (sigs
, signum
+ 1);
4088 sigaddset (sigs
, signum
+ 2);
4090 sigaddset (sigs
, signum
+ 3);
4092 sigaddset (sigs
, signum
+ 4);
4098 /* Find process PID's pending signals from /proc/pid/status and set
4102 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4103 sigset_t
*blocked
, sigset_t
*ignored
)
4106 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4107 struct cleanup
*cleanup
;
4109 sigemptyset (pending
);
4110 sigemptyset (blocked
);
4111 sigemptyset (ignored
);
4112 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4113 procfile
= gdb_fopen_cloexec (fname
, "r");
4114 if (procfile
== NULL
)
4115 error (_("Could not open %s"), fname
);
4116 cleanup
= make_cleanup_fclose (procfile
);
4118 while (fgets (buffer
, PATH_MAX
, procfile
) != NULL
)
4120 /* Normal queued signals are on the SigPnd line in the status
4121 file. However, 2.6 kernels also have a "shared" pending
4122 queue for delivering signals to a thread group, so check for
4125 Unfortunately some Red Hat kernels include the shared pending
4126 queue but not the ShdPnd status field. */
4128 if (strncmp (buffer
, "SigPnd:\t", 8) == 0)
4129 add_line_to_sigset (buffer
+ 8, pending
);
4130 else if (strncmp (buffer
, "ShdPnd:\t", 8) == 0)
4131 add_line_to_sigset (buffer
+ 8, pending
);
4132 else if (strncmp (buffer
, "SigBlk:\t", 8) == 0)
4133 add_line_to_sigset (buffer
+ 8, blocked
);
4134 else if (strncmp (buffer
, "SigIgn:\t", 8) == 0)
4135 add_line_to_sigset (buffer
+ 8, ignored
);
4138 do_cleanups (cleanup
);
4141 static enum target_xfer_status
4142 linux_nat_xfer_osdata (struct target_ops
*ops
, enum target_object object
,
4143 const char *annex
, gdb_byte
*readbuf
,
4144 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4145 ULONGEST
*xfered_len
)
4147 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4149 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4150 if (*xfered_len
== 0)
4151 return TARGET_XFER_EOF
;
4153 return TARGET_XFER_OK
;
4156 static enum target_xfer_status
4157 linux_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4158 const char *annex
, gdb_byte
*readbuf
,
4159 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4160 ULONGEST
*xfered_len
)
4162 enum target_xfer_status xfer
;
4164 if (object
== TARGET_OBJECT_AUXV
)
4165 return memory_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4166 offset
, len
, xfered_len
);
4168 if (object
== TARGET_OBJECT_OSDATA
)
4169 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4170 offset
, len
, xfered_len
);
4172 if (object
== TARGET_OBJECT_SPU
)
4173 return linux_proc_xfer_spu (ops
, object
, annex
, readbuf
, writebuf
,
4174 offset
, len
, xfered_len
);
4176 /* GDB calculates all the addresses in possibly larget width of the address.
4177 Address width needs to be masked before its final use - either by
4178 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4180 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4182 if (object
== TARGET_OBJECT_MEMORY
)
4184 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
4186 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
4187 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
4190 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4191 offset
, len
, xfered_len
);
4192 if (xfer
!= TARGET_XFER_EOF
)
4195 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4196 offset
, len
, xfered_len
);
4200 cleanup_target_stop (void *arg
)
4202 ptid_t
*ptid
= (ptid_t
*) arg
;
4204 gdb_assert (arg
!= NULL
);
4207 target_resume (*ptid
, 0, GDB_SIGNAL_0
);
4210 static VEC(static_tracepoint_marker_p
) *
4211 linux_child_static_tracepoint_markers_by_strid (struct target_ops
*self
,
4214 char s
[IPA_CMD_BUF_SIZE
];
4215 struct cleanup
*old_chain
;
4216 int pid
= ptid_get_pid (inferior_ptid
);
4217 VEC(static_tracepoint_marker_p
) *markers
= NULL
;
4218 struct static_tracepoint_marker
*marker
= NULL
;
4220 ptid_t ptid
= ptid_build (pid
, 0, 0);
4225 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4226 s
[sizeof ("qTfSTM")] = 0;
4228 agent_run_command (pid
, s
, strlen (s
) + 1);
4230 old_chain
= make_cleanup (free_current_marker
, &marker
);
4231 make_cleanup (cleanup_target_stop
, &ptid
);
4236 marker
= XCNEW (struct static_tracepoint_marker
);
4240 parse_static_tracepoint_marker_definition (p
, &p
, marker
);
4242 if (strid
== NULL
|| strcmp (strid
, marker
->str_id
) == 0)
4244 VEC_safe_push (static_tracepoint_marker_p
,
4250 release_static_tracepoint_marker (marker
);
4251 memset (marker
, 0, sizeof (*marker
));
4254 while (*p
++ == ','); /* comma-separated list */
4256 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4257 s
[sizeof ("qTsSTM")] = 0;
4258 agent_run_command (pid
, s
, strlen (s
) + 1);
4262 do_cleanups (old_chain
);
4267 /* Create a prototype generic GNU/Linux target. The client can override
4268 it with local methods. */
4271 linux_target_install_ops (struct target_ops
*t
)
4273 t
->to_insert_fork_catchpoint
= linux_child_insert_fork_catchpoint
;
4274 t
->to_remove_fork_catchpoint
= linux_child_remove_fork_catchpoint
;
4275 t
->to_insert_vfork_catchpoint
= linux_child_insert_vfork_catchpoint
;
4276 t
->to_remove_vfork_catchpoint
= linux_child_remove_vfork_catchpoint
;
4277 t
->to_insert_exec_catchpoint
= linux_child_insert_exec_catchpoint
;
4278 t
->to_remove_exec_catchpoint
= linux_child_remove_exec_catchpoint
;
4279 t
->to_set_syscall_catchpoint
= linux_child_set_syscall_catchpoint
;
4280 t
->to_pid_to_exec_file
= linux_child_pid_to_exec_file
;
4281 t
->to_post_startup_inferior
= linux_child_post_startup_inferior
;
4282 t
->to_post_attach
= linux_child_post_attach
;
4283 t
->to_follow_fork
= linux_child_follow_fork
;
4285 super_xfer_partial
= t
->to_xfer_partial
;
4286 t
->to_xfer_partial
= linux_xfer_partial
;
4288 t
->to_static_tracepoint_markers_by_strid
4289 = linux_child_static_tracepoint_markers_by_strid
;
4295 struct target_ops
*t
;
4297 t
= inf_ptrace_target ();
4298 linux_target_install_ops (t
);
4304 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4306 struct target_ops
*t
;
4308 t
= inf_ptrace_trad_target (register_u_offset
);
4309 linux_target_install_ops (t
);
4314 /* target_is_async_p implementation. */
4317 linux_nat_is_async_p (struct target_ops
*ops
)
4319 return linux_is_async_p ();
4322 /* target_can_async_p implementation. */
4325 linux_nat_can_async_p (struct target_ops
*ops
)
4327 /* NOTE: palves 2008-03-21: We're only async when the user requests
4328 it explicitly with the "set target-async" command.
4329 Someday, linux will always be async. */
4330 return target_async_permitted
;
4334 linux_nat_supports_non_stop (struct target_ops
*self
)
4339 /* True if we want to support multi-process. To be removed when GDB
4340 supports multi-exec. */
4342 int linux_multi_process
= 1;
4345 linux_nat_supports_multi_process (struct target_ops
*self
)
4347 return linux_multi_process
;
4351 linux_nat_supports_disable_randomization (struct target_ops
*self
)
4353 #ifdef HAVE_PERSONALITY
4360 static int async_terminal_is_ours
= 1;
4362 /* target_terminal_inferior implementation.
4364 This is a wrapper around child_terminal_inferior to add async support. */
4367 linux_nat_terminal_inferior (struct target_ops
*self
)
4369 /* Like target_terminal_inferior, use target_can_async_p, not
4370 target_is_async_p, since at this point the target is not async
4371 yet. If it can async, then we know it will become async prior to
4373 if (!target_can_async_p ())
4375 /* Async mode is disabled. */
4376 child_terminal_inferior (self
);
4380 child_terminal_inferior (self
);
4382 /* Calls to target_terminal_*() are meant to be idempotent. */
4383 if (!async_terminal_is_ours
)
4386 delete_file_handler (input_fd
);
4387 async_terminal_is_ours
= 0;
4391 /* target_terminal_ours implementation.
4393 This is a wrapper around child_terminal_ours to add async support (and
4394 implement the target_terminal_ours vs target_terminal_ours_for_output
4395 distinction). child_terminal_ours is currently no different than
4396 child_terminal_ours_for_output.
4397 We leave target_terminal_ours_for_output alone, leaving it to
4398 child_terminal_ours_for_output. */
4401 linux_nat_terminal_ours (struct target_ops
*self
)
4403 /* GDB should never give the terminal to the inferior if the
4404 inferior is running in the background (run&, continue&, etc.),
4405 but claiming it sure should. */
4406 child_terminal_ours (self
);
4408 if (async_terminal_is_ours
)
4411 clear_sigint_trap ();
4412 add_file_handler (input_fd
, stdin_event_handler
, 0);
4413 async_terminal_is_ours
= 1;
4416 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4418 static void *async_client_context
;
4420 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4421 so we notice when any child changes state, and notify the
4422 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4423 above to wait for the arrival of a SIGCHLD. */
4426 sigchld_handler (int signo
)
4428 int old_errno
= errno
;
4430 if (debug_linux_nat
)
4431 ui_file_write_async_safe (gdb_stdlog
,
4432 "sigchld\n", sizeof ("sigchld\n") - 1);
4434 if (signo
== SIGCHLD
4435 && linux_nat_event_pipe
[0] != -1)
4436 async_file_mark (); /* Let the event loop know that there are
4437 events to handle. */
4442 /* Callback registered with the target events file descriptor. */
4445 handle_target_event (int error
, gdb_client_data client_data
)
4447 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4450 /* Create/destroy the target events pipe. Returns previous state. */
4453 linux_async_pipe (int enable
)
4455 int previous
= linux_is_async_p ();
4457 if (previous
!= enable
)
4461 /* Block child signals while we create/destroy the pipe, as
4462 their handler writes to it. */
4463 block_child_signals (&prev_mask
);
4467 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4468 internal_error (__FILE__
, __LINE__
,
4469 "creating event pipe failed.");
4471 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4472 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4476 close (linux_nat_event_pipe
[0]);
4477 close (linux_nat_event_pipe
[1]);
4478 linux_nat_event_pipe
[0] = -1;
4479 linux_nat_event_pipe
[1] = -1;
4482 restore_child_signals_mask (&prev_mask
);
4488 /* target_async implementation. */
4491 linux_nat_async (struct target_ops
*ops
,
4492 void (*callback
) (enum inferior_event_type event_type
,
4496 if (callback
!= NULL
)
4498 async_client_callback
= callback
;
4499 async_client_context
= context
;
4500 if (!linux_async_pipe (1))
4502 add_file_handler (linux_nat_event_pipe
[0],
4503 handle_target_event
, NULL
);
4504 /* There may be pending events to handle. Tell the event loop
4511 async_client_callback
= callback
;
4512 async_client_context
= context
;
4513 delete_file_handler (linux_nat_event_pipe
[0]);
4514 linux_async_pipe (0);
4519 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4523 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4527 if (debug_linux_nat
)
4528 fprintf_unfiltered (gdb_stdlog
,
4529 "LNSL: running -> suspending %s\n",
4530 target_pid_to_str (lwp
->ptid
));
4533 if (lwp
->last_resume_kind
== resume_stop
)
4535 if (debug_linux_nat
)
4536 fprintf_unfiltered (gdb_stdlog
,
4537 "linux-nat: already stopping LWP %ld at "
4539 ptid_get_lwp (lwp
->ptid
));
4543 stop_callback (lwp
, NULL
);
4544 lwp
->last_resume_kind
= resume_stop
;
4548 /* Already known to be stopped; do nothing. */
4550 if (debug_linux_nat
)
4552 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4553 fprintf_unfiltered (gdb_stdlog
,
4554 "LNSL: already stopped/stop_requested %s\n",
4555 target_pid_to_str (lwp
->ptid
));
4557 fprintf_unfiltered (gdb_stdlog
,
4558 "LNSL: already stopped/no "
4559 "stop_requested yet %s\n",
4560 target_pid_to_str (lwp
->ptid
));
4567 linux_nat_stop (struct target_ops
*self
, ptid_t ptid
)
4570 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4572 linux_ops
->to_stop (linux_ops
, ptid
);
4576 linux_nat_close (struct target_ops
*self
)
4578 /* Unregister from the event loop. */
4579 if (linux_nat_is_async_p (self
))
4580 linux_nat_async (self
, NULL
, NULL
);
4582 if (linux_ops
->to_close
)
4583 linux_ops
->to_close (linux_ops
);
4588 /* When requests are passed down from the linux-nat layer to the
4589 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4590 used. The address space pointer is stored in the inferior object,
4591 but the common code that is passed such ptid can't tell whether
4592 lwpid is a "main" process id or not (it assumes so). We reverse
4593 look up the "main" process id from the lwp here. */
4595 static struct address_space
*
4596 linux_nat_thread_address_space (struct target_ops
*t
, ptid_t ptid
)
4598 struct lwp_info
*lwp
;
4599 struct inferior
*inf
;
4602 if (ptid_get_lwp (ptid
) == 0)
4604 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4606 lwp
= find_lwp_pid (ptid
);
4607 pid
= ptid_get_pid (lwp
->ptid
);
4611 /* A (pid,lwpid,0) ptid. */
4612 pid
= ptid_get_pid (ptid
);
4615 inf
= find_inferior_pid (pid
);
4616 gdb_assert (inf
!= NULL
);
4620 /* Return the cached value of the processor core for thread PTID. */
4623 linux_nat_core_of_thread (struct target_ops
*ops
, ptid_t ptid
)
4625 struct lwp_info
*info
= find_lwp_pid (ptid
);
4633 linux_nat_add_target (struct target_ops
*t
)
4635 /* Save the provided single-threaded target. We save this in a separate
4636 variable because another target we've inherited from (e.g. inf-ptrace)
4637 may have saved a pointer to T; we want to use it for the final
4638 process stratum target. */
4639 linux_ops_saved
= *t
;
4640 linux_ops
= &linux_ops_saved
;
4642 /* Override some methods for multithreading. */
4643 t
->to_create_inferior
= linux_nat_create_inferior
;
4644 t
->to_attach
= linux_nat_attach
;
4645 t
->to_detach
= linux_nat_detach
;
4646 t
->to_resume
= linux_nat_resume
;
4647 t
->to_wait
= linux_nat_wait
;
4648 t
->to_pass_signals
= linux_nat_pass_signals
;
4649 t
->to_xfer_partial
= linux_nat_xfer_partial
;
4650 t
->to_kill
= linux_nat_kill
;
4651 t
->to_mourn_inferior
= linux_nat_mourn_inferior
;
4652 t
->to_thread_alive
= linux_nat_thread_alive
;
4653 t
->to_pid_to_str
= linux_nat_pid_to_str
;
4654 t
->to_thread_name
= linux_nat_thread_name
;
4655 t
->to_has_thread_control
= tc_schedlock
;
4656 t
->to_thread_address_space
= linux_nat_thread_address_space
;
4657 t
->to_stopped_by_watchpoint
= linux_nat_stopped_by_watchpoint
;
4658 t
->to_stopped_data_address
= linux_nat_stopped_data_address
;
4660 t
->to_can_async_p
= linux_nat_can_async_p
;
4661 t
->to_is_async_p
= linux_nat_is_async_p
;
4662 t
->to_supports_non_stop
= linux_nat_supports_non_stop
;
4663 t
->to_async
= linux_nat_async
;
4664 t
->to_terminal_inferior
= linux_nat_terminal_inferior
;
4665 t
->to_terminal_ours
= linux_nat_terminal_ours
;
4667 super_close
= t
->to_close
;
4668 t
->to_close
= linux_nat_close
;
4670 /* Methods for non-stop support. */
4671 t
->to_stop
= linux_nat_stop
;
4673 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
4675 t
->to_supports_disable_randomization
4676 = linux_nat_supports_disable_randomization
;
4678 t
->to_core_of_thread
= linux_nat_core_of_thread
;
4680 /* We don't change the stratum; this target will sit at
4681 process_stratum and thread_db will set at thread_stratum. This
4682 is a little strange, since this is a multi-threaded-capable
4683 target, but we want to be on the stack below thread_db, and we
4684 also want to be used for single-threaded processes. */
4689 /* Register a method to call whenever a new thread is attached. */
4691 linux_nat_set_new_thread (struct target_ops
*t
,
4692 void (*new_thread
) (struct lwp_info
*))
4694 /* Save the pointer. We only support a single registered instance
4695 of the GNU/Linux native target, so we do not need to map this to
4697 linux_nat_new_thread
= new_thread
;
4700 /* See declaration in linux-nat.h. */
4703 linux_nat_set_new_fork (struct target_ops
*t
,
4704 linux_nat_new_fork_ftype
*new_fork
)
4706 /* Save the pointer. */
4707 linux_nat_new_fork
= new_fork
;
4710 /* See declaration in linux-nat.h. */
4713 linux_nat_set_forget_process (struct target_ops
*t
,
4714 linux_nat_forget_process_ftype
*fn
)
4716 /* Save the pointer. */
4717 linux_nat_forget_process_hook
= fn
;
4720 /* See declaration in linux-nat.h. */
4723 linux_nat_forget_process (pid_t pid
)
4725 if (linux_nat_forget_process_hook
!= NULL
)
4726 linux_nat_forget_process_hook (pid
);
4729 /* Register a method that converts a siginfo object between the layout
4730 that ptrace returns, and the layout in the architecture of the
4733 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4734 int (*siginfo_fixup
) (siginfo_t
*,
4738 /* Save the pointer. */
4739 linux_nat_siginfo_fixup
= siginfo_fixup
;
4742 /* Register a method to call prior to resuming a thread. */
4745 linux_nat_set_prepare_to_resume (struct target_ops
*t
,
4746 void (*prepare_to_resume
) (struct lwp_info
*))
4748 /* Save the pointer. */
4749 linux_nat_prepare_to_resume
= prepare_to_resume
;
4752 /* See linux-nat.h. */
4755 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4759 pid
= ptid_get_lwp (ptid
);
4761 pid
= ptid_get_pid (ptid
);
4764 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4767 memset (siginfo
, 0, sizeof (*siginfo
));
4773 /* Provide a prototype to silence -Wmissing-prototypes. */
4774 extern initialize_file_ftype _initialize_linux_nat
;
4777 _initialize_linux_nat (void)
4779 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4780 &debug_linux_nat
, _("\
4781 Set debugging of GNU/Linux lwp module."), _("\
4782 Show debugging of GNU/Linux lwp module."), _("\
4783 Enables printf debugging output."),
4785 show_debug_linux_nat
,
4786 &setdebuglist
, &showdebuglist
);
4788 /* Save this mask as the default. */
4789 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
4791 /* Install a SIGCHLD handler. */
4792 sigchld_action
.sa_handler
= sigchld_handler
;
4793 sigemptyset (&sigchld_action
.sa_mask
);
4794 sigchld_action
.sa_flags
= SA_RESTART
;
4796 /* Make it the default. */
4797 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4799 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4800 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4801 sigdelset (&suspend_mask
, SIGCHLD
);
4803 sigemptyset (&blocked_mask
);
4805 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
4806 support read-only process state. */
4807 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
4808 | PTRACE_O_TRACEVFORKDONE
4809 | PTRACE_O_TRACEVFORK
4810 | PTRACE_O_TRACEFORK
4811 | PTRACE_O_TRACEEXEC
);
4815 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4816 the GNU/Linux Threads library and therefore doesn't really belong
4819 /* Read variable NAME in the target and return its value if found.
4820 Otherwise return zero. It is assumed that the type of the variable
4824 get_signo (const char *name
)
4826 struct bound_minimal_symbol ms
;
4829 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
4830 if (ms
.minsym
== NULL
)
4833 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
4834 sizeof (signo
)) != 0)
4840 /* Return the set of signals used by the threads library in *SET. */
4843 lin_thread_get_thread_signals (sigset_t
*set
)
4845 struct sigaction action
;
4846 int restart
, cancel
;
4848 sigemptyset (&blocked_mask
);
4851 restart
= get_signo ("__pthread_sig_restart");
4852 cancel
= get_signo ("__pthread_sig_cancel");
4854 /* LinuxThreads normally uses the first two RT signals, but in some legacy
4855 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
4856 not provide any way for the debugger to query the signal numbers -
4857 fortunately they don't change! */
4860 restart
= __SIGRTMIN
;
4863 cancel
= __SIGRTMIN
+ 1;
4865 sigaddset (set
, restart
);
4866 sigaddset (set
, cancel
);
4868 /* The GNU/Linux Threads library makes terminating threads send a
4869 special "cancel" signal instead of SIGCHLD. Make sure we catch
4870 those (to prevent them from terminating GDB itself, which is
4871 likely to be their default action) and treat them the same way as
4874 action
.sa_handler
= sigchld_handler
;
4875 sigemptyset (&action
.sa_mask
);
4876 action
.sa_flags
= SA_RESTART
;
4877 sigaction (cancel
, &action
, NULL
);
4879 /* We block the "cancel" signal throughout this code ... */
4880 sigaddset (&blocked_mask
, cancel
);
4881 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
4883 /* ... except during a sigsuspend. */
4884 sigdelset (&suspend_mask
, cancel
);