1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2014 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
28 #include "gdb_assert.h"
29 #ifdef HAVE_TKILL_SYSCALL
31 #include <sys/syscall.h>
33 #include <sys/ptrace.h>
34 #include "linux-nat.h"
35 #include "nat/linux-ptrace.h"
36 #include "nat/linux-procfs.h"
37 #include "linux-fork.h"
38 #include "gdbthread.h"
42 #include "inf-child.h"
43 #include "inf-ptrace.h"
45 #include <sys/procfs.h> /* for elf_gregset etc. */
46 #include "elf-bfd.h" /* for elfcore_write_* */
47 #include "gregset.h" /* for gregset */
48 #include "gdbcore.h" /* for get_exec_file */
49 #include <ctype.h> /* for isdigit */
50 #include <sys/stat.h> /* for struct stat */
51 #include <fcntl.h> /* for O_RDONLY */
53 #include "event-loop.h"
54 #include "event-top.h"
56 #include <sys/types.h>
58 #include "xml-support.h"
62 #include "nat/linux-osdata.h"
63 #include "linux-tdep.h"
66 #include "tracepoint.h"
67 #include "exceptions.h"
69 #include "target-descriptions.h"
70 #include "filestuff.h"
74 #define SPUFS_MAGIC 0x23c9b64e
77 #ifdef HAVE_PERSONALITY
78 # include <sys/personality.h>
79 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
80 # define ADDR_NO_RANDOMIZE 0x0040000
82 #endif /* HAVE_PERSONALITY */
84 /* This comment documents high-level logic of this file.
86 Waiting for events in sync mode
87 ===============================
89 When waiting for an event in a specific thread, we just use waitpid, passing
90 the specific pid, and not passing WNOHANG.
92 When waiting for an event in all threads, waitpid is not quite good. Prior to
93 version 2.4, Linux can either wait for event in main thread, or in secondary
94 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
95 miss an event. The solution is to use non-blocking waitpid, together with
96 sigsuspend. First, we use non-blocking waitpid to get an event in the main
97 process, if any. Second, we use non-blocking waitpid with the __WCLONED
98 flag to check for events in cloned processes. If nothing is found, we use
99 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
100 happened to a child process -- and SIGCHLD will be delivered both for events
101 in main debugged process and in cloned processes. As soon as we know there's
102 an event, we get back to calling nonblocking waitpid with and without
105 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
106 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
107 blocked, the signal becomes pending and sigsuspend immediately
108 notices it and returns.
110 Waiting for events in async mode
111 ================================
113 In async mode, GDB should always be ready to handle both user input
114 and target events, so neither blocking waitpid nor sigsuspend are
115 viable options. Instead, we should asynchronously notify the GDB main
116 event loop whenever there's an unprocessed event from the target. We
117 detect asynchronous target events by handling SIGCHLD signals. To
118 notify the event loop about target events, the self-pipe trick is used
119 --- a pipe is registered as waitable event source in the event loop,
120 the event loop select/poll's on the read end of this pipe (as well on
121 other event sources, e.g., stdin), and the SIGCHLD handler writes a
122 byte to this pipe. This is more portable than relying on
123 pselect/ppoll, since on kernels that lack those syscalls, libc
124 emulates them with select/poll+sigprocmask, and that is racy
125 (a.k.a. plain broken).
127 Obviously, if we fail to notify the event loop if there's a target
128 event, it's bad. OTOH, if we notify the event loop when there's no
129 event from the target, linux_nat_wait will detect that there's no real
130 event to report, and return event of type TARGET_WAITKIND_IGNORE.
131 This is mostly harmless, but it will waste time and is better avoided.
133 The main design point is that every time GDB is outside linux-nat.c,
134 we have a SIGCHLD handler installed that is called when something
135 happens to the target and notifies the GDB event loop. Whenever GDB
136 core decides to handle the event, and calls into linux-nat.c, we
137 process things as in sync mode, except that the we never block in
140 While processing an event, we may end up momentarily blocked in
141 waitpid calls. Those waitpid calls, while blocking, are guarantied to
142 return quickly. E.g., in all-stop mode, before reporting to the core
143 that an LWP hit a breakpoint, all LWPs are stopped by sending them
144 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
145 Note that this is different from blocking indefinitely waiting for the
146 next event --- here, we're already handling an event.
151 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
152 signal is not entirely significant; we just need for a signal to be delivered,
153 so that we can intercept it. SIGSTOP's advantage is that it can not be
154 blocked. A disadvantage is that it is not a real-time signal, so it can only
155 be queued once; we do not keep track of other sources of SIGSTOP.
157 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
158 use them, because they have special behavior when the signal is generated -
159 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
160 kills the entire thread group.
162 A delivered SIGSTOP would stop the entire thread group, not just the thread we
163 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
164 cancel it (by PTRACE_CONT without passing SIGSTOP).
166 We could use a real-time signal instead. This would solve those problems; we
167 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
168 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
169 generates it, and there are races with trying to find a signal that is not
173 #define O_LARGEFILE 0
176 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
177 the use of the multi-threaded target. */
178 static struct target_ops
*linux_ops
;
179 static struct target_ops linux_ops_saved
;
181 /* The method to call, if any, when a new thread is attached. */
182 static void (*linux_nat_new_thread
) (struct lwp_info
*);
184 /* The method to call, if any, when a new fork is attached. */
185 static linux_nat_new_fork_ftype
*linux_nat_new_fork
;
187 /* The method to call, if any, when a process is no longer
189 static linux_nat_forget_process_ftype
*linux_nat_forget_process_hook
;
191 /* Hook to call prior to resuming a thread. */
192 static void (*linux_nat_prepare_to_resume
) (struct lwp_info
*);
194 /* The method to call, if any, when the siginfo object needs to be
195 converted between the layout returned by ptrace, and the layout in
196 the architecture of the inferior. */
197 static int (*linux_nat_siginfo_fixup
) (siginfo_t
*,
201 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
202 Called by our to_xfer_partial. */
203 static target_xfer_partial_ftype
*super_xfer_partial
;
205 /* The saved to_close method, inherited from inf-ptrace.c.
206 Called by our to_close. */
207 static void (*super_close
) (struct target_ops
*);
209 static unsigned int debug_linux_nat
;
211 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
212 struct cmd_list_element
*c
, const char *value
)
214 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
218 struct simple_pid_list
222 struct simple_pid_list
*next
;
224 struct simple_pid_list
*stopped_pids
;
226 /* Async mode support. */
228 /* The read/write ends of the pipe registered as waitable file in the
230 static int linux_nat_event_pipe
[2] = { -1, -1 };
232 /* Flush the event pipe. */
235 async_file_flush (void)
242 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
244 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
247 /* Put something (anything, doesn't matter what, or how much) in event
248 pipe, so that the select/poll in the event-loop realizes we have
249 something to process. */
252 async_file_mark (void)
256 /* It doesn't really matter what the pipe contains, as long we end
257 up with something in it. Might as well flush the previous
263 ret
= write (linux_nat_event_pipe
[1], "+", 1);
265 while (ret
== -1 && errno
== EINTR
);
267 /* Ignore EAGAIN. If the pipe is full, the event loop will already
268 be awakened anyway. */
271 static int kill_lwp (int lwpid
, int signo
);
273 static int stop_callback (struct lwp_info
*lp
, void *data
);
275 static void block_child_signals (sigset_t
*prev_mask
);
276 static void restore_child_signals_mask (sigset_t
*prev_mask
);
279 static struct lwp_info
*add_lwp (ptid_t ptid
);
280 static void purge_lwp_list (int pid
);
281 static void delete_lwp (ptid_t ptid
);
282 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
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
328 features given PID. */
331 linux_init_ptrace (pid_t pid
)
333 linux_enable_event_reporting (pid
);
334 linux_ptrace_init_warnings ();
338 linux_child_post_attach (struct target_ops
*self
, int pid
)
340 linux_init_ptrace (pid
);
344 linux_child_post_startup_inferior (struct target_ops
*self
, ptid_t ptid
)
346 linux_init_ptrace (ptid_get_pid (ptid
));
349 /* Return the number of known LWPs in the tgid given by PID. */
357 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
358 if (ptid_get_pid (lp
->ptid
) == pid
)
364 /* Call delete_lwp with prototype compatible for make_cleanup. */
367 delete_lwp_cleanup (void *lp_voidp
)
369 struct lwp_info
*lp
= lp_voidp
;
371 delete_lwp (lp
->ptid
);
375 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
,
379 int parent_pid
, child_pid
;
381 has_vforked
= (inferior_thread ()->pending_follow
.kind
382 == TARGET_WAITKIND_VFORKED
);
383 parent_pid
= ptid_get_lwp (inferior_ptid
);
385 parent_pid
= ptid_get_pid (inferior_ptid
);
387 = ptid_get_pid (inferior_thread ()->pending_follow
.value
.related_pid
);
390 && !non_stop
/* Non-stop always resumes both branches. */
391 && (!target_is_async_p () || sync_execution
)
392 && !(follow_child
|| detach_fork
|| sched_multi
))
394 /* The parent stays blocked inside the vfork syscall until the
395 child execs or exits. If we don't let the child run, then
396 the parent stays blocked. If we're telling the parent to run
397 in the foreground, the user will not be able to ctrl-c to get
398 back the terminal, effectively hanging the debug session. */
399 fprintf_filtered (gdb_stderr
, _("\
400 Can not resume the parent process over vfork in the foreground while\n\
401 holding the child stopped. Try \"set detach-on-fork\" or \
402 \"set schedule-multiple\".\n"));
403 /* FIXME output string > 80 columns. */
409 struct lwp_info
*child_lp
= NULL
;
411 /* We're already attached to the parent, by default. */
413 /* Detach new forked process? */
416 struct cleanup
*old_chain
;
417 int status
= W_STOPCODE (0);
419 /* Before detaching from the child, remove all breakpoints
420 from it. If we forked, then this has already been taken
421 care of by infrun.c. If we vforked however, any
422 breakpoint inserted in the parent is visible in the
423 child, even those added while stopped in a vfork
424 catchpoint. This will remove the breakpoints from the
425 parent also, but they'll be reinserted below. */
428 /* keep breakpoints list in sync. */
429 remove_breakpoints_pid (ptid_get_pid (inferior_ptid
));
432 if (info_verbose
|| debug_linux_nat
)
434 target_terminal_ours ();
435 fprintf_filtered (gdb_stdlog
,
436 "Detaching after fork from "
437 "child process %d.\n",
441 old_chain
= save_inferior_ptid ();
442 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
444 child_lp
= add_lwp (inferior_ptid
);
445 child_lp
->stopped
= 1;
446 child_lp
->last_resume_kind
= resume_stop
;
447 make_cleanup (delete_lwp_cleanup
, child_lp
);
449 if (linux_nat_prepare_to_resume
!= NULL
)
450 linux_nat_prepare_to_resume (child_lp
);
452 /* When debugging an inferior in an architecture that supports
453 hardware single stepping on a kernel without commit
454 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
455 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
456 set if the parent process had them set.
457 To work around this, single step the child process
458 once before detaching to clear the flags. */
460 if (!gdbarch_software_single_step_p (target_thread_architecture
463 linux_disable_event_reporting (child_pid
);
464 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
465 perror_with_name (_("Couldn't do single step"));
466 if (my_waitpid (child_pid
, &status
, 0) < 0)
467 perror_with_name (_("Couldn't wait vfork process"));
470 if (WIFSTOPPED (status
))
474 signo
= WSTOPSIG (status
);
476 && !signal_pass_state (gdb_signal_from_host (signo
)))
478 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
481 do_cleanups (old_chain
);
485 struct inferior
*parent_inf
, *child_inf
;
486 struct cleanup
*old_chain
;
488 /* Add process to GDB's tables. */
489 child_inf
= add_inferior (child_pid
);
491 parent_inf
= current_inferior ();
492 child_inf
->attach_flag
= parent_inf
->attach_flag
;
493 copy_terminal_info (child_inf
, parent_inf
);
494 child_inf
->gdbarch
= parent_inf
->gdbarch
;
495 copy_inferior_target_desc_info (child_inf
, parent_inf
);
497 old_chain
= save_inferior_ptid ();
498 save_current_program_space ();
500 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
501 add_thread (inferior_ptid
);
502 child_lp
= add_lwp (inferior_ptid
);
503 child_lp
->stopped
= 1;
504 child_lp
->last_resume_kind
= resume_stop
;
505 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
507 /* If this is a vfork child, then the address-space is
508 shared with the parent. */
511 child_inf
->pspace
= parent_inf
->pspace
;
512 child_inf
->aspace
= parent_inf
->aspace
;
514 /* The parent will be frozen until the child is done
515 with the shared region. Keep track of the
517 child_inf
->vfork_parent
= parent_inf
;
518 child_inf
->pending_detach
= 0;
519 parent_inf
->vfork_child
= child_inf
;
520 parent_inf
->pending_detach
= 0;
524 child_inf
->aspace
= new_address_space ();
525 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
526 child_inf
->removable
= 1;
527 set_current_program_space (child_inf
->pspace
);
528 clone_program_space (child_inf
->pspace
, parent_inf
->pspace
);
530 /* Let the shared library layer (solib-svr4) learn about
531 this new process, relocate the cloned exec, pull in
532 shared libraries, and install the solib event
533 breakpoint. If a "cloned-VM" event was propagated
534 better throughout the core, this wouldn't be
536 solib_create_inferior_hook (0);
539 /* Let the thread_db layer learn about this new process. */
540 check_for_thread_db ();
542 do_cleanups (old_chain
);
547 struct lwp_info
*parent_lp
;
548 struct inferior
*parent_inf
;
550 parent_inf
= current_inferior ();
552 /* If we detached from the child, then we have to be careful
553 to not insert breakpoints in the parent until the child
554 is done with the shared memory region. However, if we're
555 staying attached to the child, then we can and should
556 insert breakpoints, so that we can debug it. A
557 subsequent child exec or exit is enough to know when does
558 the child stops using the parent's address space. */
559 parent_inf
->waiting_for_vfork_done
= detach_fork
;
560 parent_inf
->pspace
->breakpoints_not_allowed
= detach_fork
;
562 parent_lp
= find_lwp_pid (pid_to_ptid (parent_pid
));
563 gdb_assert (linux_supports_tracefork () >= 0);
565 if (linux_supports_tracevforkdone ())
568 fprintf_unfiltered (gdb_stdlog
,
569 "LCFF: waiting for VFORK_DONE on %d\n",
571 parent_lp
->stopped
= 1;
573 /* We'll handle the VFORK_DONE event like any other
574 event, in target_wait. */
578 /* We can't insert breakpoints until the child has
579 finished with the shared memory region. We need to
580 wait until that happens. Ideal would be to just
582 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
583 - waitpid (parent_pid, &status, __WALL);
584 However, most architectures can't handle a syscall
585 being traced on the way out if it wasn't traced on
588 We might also think to loop, continuing the child
589 until it exits or gets a SIGTRAP. One problem is
590 that the child might call ptrace with PTRACE_TRACEME.
592 There's no simple and reliable way to figure out when
593 the vforked child will be done with its copy of the
594 shared memory. We could step it out of the syscall,
595 two instructions, let it go, and then single-step the
596 parent once. When we have hardware single-step, this
597 would work; with software single-step it could still
598 be made to work but we'd have to be able to insert
599 single-step breakpoints in the child, and we'd have
600 to insert -just- the single-step breakpoint in the
601 parent. Very awkward.
603 In the end, the best we can do is to make sure it
604 runs for a little while. Hopefully it will be out of
605 range of any breakpoints we reinsert. Usually this
606 is only the single-step breakpoint at vfork's return
610 fprintf_unfiltered (gdb_stdlog
,
611 "LCFF: no VFORK_DONE "
612 "support, sleeping a bit\n");
616 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
617 and leave it pending. The next linux_nat_resume call
618 will notice a pending event, and bypasses actually
619 resuming the inferior. */
620 parent_lp
->status
= 0;
621 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
622 parent_lp
->stopped
= 1;
624 /* If we're in async mode, need to tell the event loop
625 there's something here to process. */
626 if (target_can_async_p ())
633 struct inferior
*parent_inf
, *child_inf
;
634 struct lwp_info
*child_lp
;
635 struct program_space
*parent_pspace
;
637 if (info_verbose
|| debug_linux_nat
)
639 target_terminal_ours ();
641 fprintf_filtered (gdb_stdlog
,
642 _("Attaching after process %d "
643 "vfork to child process %d.\n"),
644 parent_pid
, child_pid
);
646 fprintf_filtered (gdb_stdlog
,
647 _("Attaching after process %d "
648 "fork to child process %d.\n"),
649 parent_pid
, child_pid
);
652 /* Add the new inferior first, so that the target_detach below
653 doesn't unpush the target. */
655 child_inf
= add_inferior (child_pid
);
657 parent_inf
= current_inferior ();
658 child_inf
->attach_flag
= parent_inf
->attach_flag
;
659 copy_terminal_info (child_inf
, parent_inf
);
660 child_inf
->gdbarch
= parent_inf
->gdbarch
;
661 copy_inferior_target_desc_info (child_inf
, parent_inf
);
663 parent_pspace
= parent_inf
->pspace
;
665 /* If we're vforking, we want to hold on to the parent until the
666 child exits or execs. At child exec or exit time we can
667 remove the old breakpoints from the parent and detach or
668 resume debugging it. Otherwise, detach the parent now; we'll
669 want to reuse it's program/address spaces, but we can't set
670 them to the child before removing breakpoints from the
671 parent, otherwise, the breakpoints module could decide to
672 remove breakpoints from the wrong process (since they'd be
673 assigned to the same address space). */
677 gdb_assert (child_inf
->vfork_parent
== NULL
);
678 gdb_assert (parent_inf
->vfork_child
== NULL
);
679 child_inf
->vfork_parent
= parent_inf
;
680 child_inf
->pending_detach
= 0;
681 parent_inf
->vfork_child
= child_inf
;
682 parent_inf
->pending_detach
= detach_fork
;
683 parent_inf
->waiting_for_vfork_done
= 0;
685 else if (detach_fork
)
686 target_detach (NULL
, 0);
688 /* Note that the detach above makes PARENT_INF dangling. */
690 /* Add the child thread to the appropriate lists, and switch to
691 this new thread, before cloning the program space, and
692 informing the solib layer about this new process. */
694 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
695 add_thread (inferior_ptid
);
696 child_lp
= add_lwp (inferior_ptid
);
697 child_lp
->stopped
= 1;
698 child_lp
->last_resume_kind
= resume_stop
;
700 /* If this is a vfork child, then the address-space is shared
701 with the parent. If we detached from the parent, then we can
702 reuse the parent's program/address spaces. */
703 if (has_vforked
|| detach_fork
)
705 child_inf
->pspace
= parent_pspace
;
706 child_inf
->aspace
= child_inf
->pspace
->aspace
;
710 child_inf
->aspace
= new_address_space ();
711 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
712 child_inf
->removable
= 1;
713 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
714 set_current_program_space (child_inf
->pspace
);
715 clone_program_space (child_inf
->pspace
, parent_pspace
);
717 /* Let the shared library layer (solib-svr4) learn about
718 this new process, relocate the cloned exec, pull in
719 shared libraries, and install the solib event breakpoint.
720 If a "cloned-VM" event was propagated better throughout
721 the core, this wouldn't be required. */
722 solib_create_inferior_hook (0);
725 /* Let the thread_db layer learn about this new process. */
726 check_for_thread_db ();
734 linux_child_insert_fork_catchpoint (struct target_ops
*self
, int pid
)
736 return !linux_supports_tracefork ();
740 linux_child_remove_fork_catchpoint (struct target_ops
*self
, int pid
)
746 linux_child_insert_vfork_catchpoint (struct target_ops
*self
, int pid
)
748 return !linux_supports_tracefork ();
752 linux_child_remove_vfork_catchpoint (struct target_ops
*self
, int pid
)
758 linux_child_insert_exec_catchpoint (struct target_ops
*self
, int pid
)
760 return !linux_supports_tracefork ();
764 linux_child_remove_exec_catchpoint (struct target_ops
*self
, int pid
)
770 linux_child_set_syscall_catchpoint (struct target_ops
*self
,
771 int pid
, int needed
, int any_count
,
772 int table_size
, int *table
)
774 if (!linux_supports_tracesysgood ())
777 /* On GNU/Linux, we ignore the arguments. It means that we only
778 enable the syscall catchpoints, but do not disable them.
780 Also, we do not use the `table' information because we do not
781 filter system calls here. We let GDB do the logic for us. */
785 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
786 are processes sharing the same VM space. A multi-threaded process
787 is basically a group of such processes. However, such a grouping
788 is almost entirely a user-space issue; the kernel doesn't enforce
789 such a grouping at all (this might change in the future). In
790 general, we'll rely on the threads library (i.e. the GNU/Linux
791 Threads library) to provide such a grouping.
793 It is perfectly well possible to write a multi-threaded application
794 without the assistance of a threads library, by using the clone
795 system call directly. This module should be able to give some
796 rudimentary support for debugging such applications if developers
797 specify the CLONE_PTRACE flag in the clone system call, and are
798 using the Linux kernel 2.4 or above.
800 Note that there are some peculiarities in GNU/Linux that affect
803 - In general one should specify the __WCLONE flag to waitpid in
804 order to make it report events for any of the cloned processes
805 (and leave it out for the initial process). However, if a cloned
806 process has exited the exit status is only reported if the
807 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
808 we cannot use it since GDB must work on older systems too.
810 - When a traced, cloned process exits and is waited for by the
811 debugger, the kernel reassigns it to the original parent and
812 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
813 library doesn't notice this, which leads to the "zombie problem":
814 When debugged a multi-threaded process that spawns a lot of
815 threads will run out of processes, even if the threads exit,
816 because the "zombies" stay around. */
818 /* List of known LWPs. */
819 struct lwp_info
*lwp_list
;
822 /* Original signal mask. */
823 static sigset_t normal_mask
;
825 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
826 _initialize_linux_nat. */
827 static sigset_t suspend_mask
;
829 /* Signals to block to make that sigsuspend work. */
830 static sigset_t blocked_mask
;
832 /* SIGCHLD action. */
833 struct sigaction sigchld_action
;
835 /* Block child signals (SIGCHLD and linux threads signals), and store
836 the previous mask in PREV_MASK. */
839 block_child_signals (sigset_t
*prev_mask
)
841 /* Make sure SIGCHLD is blocked. */
842 if (!sigismember (&blocked_mask
, SIGCHLD
))
843 sigaddset (&blocked_mask
, SIGCHLD
);
845 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
848 /* Restore child signals mask, previously returned by
849 block_child_signals. */
852 restore_child_signals_mask (sigset_t
*prev_mask
)
854 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
857 /* Mask of signals to pass directly to the inferior. */
858 static sigset_t pass_mask
;
860 /* Update signals to pass to the inferior. */
862 linux_nat_pass_signals (struct target_ops
*self
,
863 int numsigs
, unsigned char *pass_signals
)
867 sigemptyset (&pass_mask
);
869 for (signo
= 1; signo
< NSIG
; signo
++)
871 int target_signo
= gdb_signal_from_host (signo
);
872 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
873 sigaddset (&pass_mask
, signo
);
879 /* Prototypes for local functions. */
880 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
881 static int linux_thread_alive (ptid_t ptid
);
882 static char *linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
);
886 /* Destroy and free LP. */
889 lwp_free (struct lwp_info
*lp
)
891 xfree (lp
->arch_private
);
895 /* Remove all LWPs belong to PID from the lwp list. */
898 purge_lwp_list (int pid
)
900 struct lwp_info
*lp
, *lpprev
, *lpnext
;
904 for (lp
= lwp_list
; lp
; lp
= lpnext
)
908 if (ptid_get_pid (lp
->ptid
) == pid
)
913 lpprev
->next
= lp
->next
;
922 /* Add the LWP specified by PTID to the list. PTID is the first LWP
923 in the process. Return a pointer to the structure describing the
926 This differs from add_lwp in that we don't let the arch specific
927 bits know about this new thread. Current clients of this callback
928 take the opportunity to install watchpoints in the new thread, and
929 we shouldn't do that for the first thread. If we're spawning a
930 child ("run"), the thread executes the shell wrapper first, and we
931 shouldn't touch it until it execs the program we want to debug.
932 For "attach", it'd be okay to call the callback, but it's not
933 necessary, because watchpoints can't yet have been inserted into
936 static struct lwp_info
*
937 add_initial_lwp (ptid_t ptid
)
941 gdb_assert (ptid_lwp_p (ptid
));
943 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
945 memset (lp
, 0, sizeof (struct lwp_info
));
947 lp
->last_resume_kind
= resume_continue
;
948 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
959 /* Add the LWP specified by PID to the list. Return a pointer to the
960 structure describing the new LWP. The LWP should already be
963 static struct lwp_info
*
964 add_lwp (ptid_t ptid
)
968 lp
= add_initial_lwp (ptid
);
970 /* Let the arch specific bits know about this new thread. Current
971 clients of this callback take the opportunity to install
972 watchpoints in the new thread. We don't do this for the first
973 thread though. See add_initial_lwp. */
974 if (linux_nat_new_thread
!= NULL
)
975 linux_nat_new_thread (lp
);
980 /* Remove the LWP specified by PID from the list. */
983 delete_lwp (ptid_t ptid
)
985 struct lwp_info
*lp
, *lpprev
;
989 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
990 if (ptid_equal (lp
->ptid
, ptid
))
997 lpprev
->next
= lp
->next
;
1004 /* Return a pointer to the structure describing the LWP corresponding
1005 to PID. If no corresponding LWP could be found, return NULL. */
1007 static struct lwp_info
*
1008 find_lwp_pid (ptid_t ptid
)
1010 struct lwp_info
*lp
;
1013 if (ptid_lwp_p (ptid
))
1014 lwp
= ptid_get_lwp (ptid
);
1016 lwp
= ptid_get_pid (ptid
);
1018 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
1019 if (lwp
== ptid_get_lwp (lp
->ptid
))
1025 /* Call CALLBACK with its second argument set to DATA for every LWP in
1026 the list. If CALLBACK returns 1 for a particular LWP, return a
1027 pointer to the structure describing that LWP immediately.
1028 Otherwise return NULL. */
1031 iterate_over_lwps (ptid_t filter
,
1032 int (*callback
) (struct lwp_info
*, void *),
1035 struct lwp_info
*lp
, *lpnext
;
1037 for (lp
= lwp_list
; lp
; lp
= lpnext
)
1041 if (ptid_match (lp
->ptid
, filter
))
1043 if ((*callback
) (lp
, data
))
1051 /* Update our internal state when changing from one checkpoint to
1052 another indicated by NEW_PTID. We can only switch single-threaded
1053 applications, so we only create one new LWP, and the previous list
1057 linux_nat_switch_fork (ptid_t new_ptid
)
1059 struct lwp_info
*lp
;
1061 purge_lwp_list (ptid_get_pid (inferior_ptid
));
1063 lp
= add_lwp (new_ptid
);
1066 /* This changes the thread's ptid while preserving the gdb thread
1067 num. Also changes the inferior pid, while preserving the
1069 thread_change_ptid (inferior_ptid
, new_ptid
);
1071 /* We've just told GDB core that the thread changed target id, but,
1072 in fact, it really is a different thread, with different register
1074 registers_changed ();
1077 /* Handle the exit of a single thread LP. */
1080 exit_lwp (struct lwp_info
*lp
)
1082 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1086 if (print_thread_events
)
1087 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
1089 delete_thread (lp
->ptid
);
1092 delete_lwp (lp
->ptid
);
1095 /* Wait for the LWP specified by LP, which we have just attached to.
1096 Returns a wait status for that LWP, to cache. */
1099 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
1102 pid_t new_pid
, pid
= ptid_get_lwp (ptid
);
1105 if (linux_proc_pid_is_stopped (pid
))
1107 if (debug_linux_nat
)
1108 fprintf_unfiltered (gdb_stdlog
,
1109 "LNPAW: Attaching to a stopped process\n");
1111 /* The process is definitely stopped. It is in a job control
1112 stop, unless the kernel predates the TASK_STOPPED /
1113 TASK_TRACED distinction, in which case it might be in a
1114 ptrace stop. Make sure it is in a ptrace stop; from there we
1115 can kill it, signal it, et cetera.
1117 First make sure there is a pending SIGSTOP. Since we are
1118 already attached, the process can not transition from stopped
1119 to running without a PTRACE_CONT; so we know this signal will
1120 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1121 probably already in the queue (unless this kernel is old
1122 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1123 is not an RT signal, it can only be queued once. */
1124 kill_lwp (pid
, SIGSTOP
);
1126 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1127 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1128 ptrace (PTRACE_CONT
, pid
, 0, 0);
1131 /* Make sure the initial process is stopped. The user-level threads
1132 layer might want to poke around in the inferior, and that won't
1133 work if things haven't stabilized yet. */
1134 new_pid
= my_waitpid (pid
, &status
, 0);
1135 if (new_pid
== -1 && errno
== ECHILD
)
1138 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
1140 /* Try again with __WCLONE to check cloned processes. */
1141 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
1145 gdb_assert (pid
== new_pid
);
1147 if (!WIFSTOPPED (status
))
1149 /* The pid we tried to attach has apparently just exited. */
1150 if (debug_linux_nat
)
1151 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1152 pid
, status_to_str (status
));
1156 if (WSTOPSIG (status
) != SIGSTOP
)
1159 if (debug_linux_nat
)
1160 fprintf_unfiltered (gdb_stdlog
,
1161 "LNPAW: Received %s after attaching\n",
1162 status_to_str (status
));
1168 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1169 the new LWP could not be attached, or 1 if we're already auto
1170 attached to this thread, but haven't processed the
1171 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1172 its existance, without considering it an error. */
1175 lin_lwp_attach_lwp (ptid_t ptid
)
1177 struct lwp_info
*lp
;
1180 gdb_assert (ptid_lwp_p (ptid
));
1182 lp
= find_lwp_pid (ptid
);
1183 lwpid
= ptid_get_lwp (ptid
);
1185 /* We assume that we're already attached to any LWP that has an id
1186 equal to the overall process id, and to any LWP that is already
1187 in our list of LWPs. If we're not seeing exit events from threads
1188 and we've had PID wraparound since we last tried to stop all threads,
1189 this assumption might be wrong; fortunately, this is very unlikely
1191 if (lwpid
!= ptid_get_pid (ptid
) && lp
== NULL
)
1193 int status
, cloned
= 0, signalled
= 0;
1195 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1197 if (linux_supports_tracefork ())
1199 /* If we haven't stopped all threads when we get here,
1200 we may have seen a thread listed in thread_db's list,
1201 but not processed the PTRACE_EVENT_CLONE yet. If
1202 that's the case, ignore this new thread, and let
1203 normal event handling discover it later. */
1204 if (in_pid_list_p (stopped_pids
, lwpid
))
1206 /* We've already seen this thread stop, but we
1207 haven't seen the PTRACE_EVENT_CLONE extended
1216 /* See if we've got a stop for this new child
1217 pending. If so, we're already attached. */
1218 new_pid
= my_waitpid (lwpid
, &status
, WNOHANG
);
1219 if (new_pid
== -1 && errno
== ECHILD
)
1220 new_pid
= my_waitpid (lwpid
, &status
, __WCLONE
| WNOHANG
);
1223 if (WIFSTOPPED (status
))
1224 add_to_pid_list (&stopped_pids
, lwpid
, status
);
1230 /* If we fail to attach to the thread, issue a warning,
1231 but continue. One way this can happen is if thread
1232 creation is interrupted; as of Linux kernel 2.6.19, a
1233 bug may place threads in the thread list and then fail
1235 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1236 safe_strerror (errno
));
1240 if (debug_linux_nat
)
1241 fprintf_unfiltered (gdb_stdlog
,
1242 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1243 target_pid_to_str (ptid
));
1245 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1246 if (!WIFSTOPPED (status
))
1249 lp
= add_lwp (ptid
);
1251 lp
->cloned
= cloned
;
1252 lp
->signalled
= signalled
;
1253 if (WSTOPSIG (status
) != SIGSTOP
)
1256 lp
->status
= status
;
1259 target_post_attach (ptid_get_lwp (lp
->ptid
));
1261 if (debug_linux_nat
)
1263 fprintf_unfiltered (gdb_stdlog
,
1264 "LLAL: waitpid %s received %s\n",
1265 target_pid_to_str (ptid
),
1266 status_to_str (status
));
1271 /* We assume that the LWP representing the original process is
1272 already stopped. Mark it as stopped in the data structure
1273 that the GNU/linux ptrace layer uses to keep track of
1274 threads. Note that this won't have already been done since
1275 the main thread will have, we assume, been stopped by an
1276 attach from a different layer. */
1278 lp
= add_lwp (ptid
);
1282 lp
->last_resume_kind
= resume_stop
;
1287 linux_nat_create_inferior (struct target_ops
*ops
,
1288 char *exec_file
, char *allargs
, char **env
,
1291 #ifdef HAVE_PERSONALITY
1292 int personality_orig
= 0, personality_set
= 0;
1293 #endif /* HAVE_PERSONALITY */
1295 /* The fork_child mechanism is synchronous and calls target_wait, so
1296 we have to mask the async mode. */
1298 #ifdef HAVE_PERSONALITY
1299 if (disable_randomization
)
1302 personality_orig
= personality (0xffffffff);
1303 if (errno
== 0 && !(personality_orig
& ADDR_NO_RANDOMIZE
))
1305 personality_set
= 1;
1306 personality (personality_orig
| ADDR_NO_RANDOMIZE
);
1308 if (errno
!= 0 || (personality_set
1309 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE
)))
1310 warning (_("Error disabling address space randomization: %s"),
1311 safe_strerror (errno
));
1313 #endif /* HAVE_PERSONALITY */
1315 /* Make sure we report all signals during startup. */
1316 linux_nat_pass_signals (ops
, 0, NULL
);
1318 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1320 #ifdef HAVE_PERSONALITY
1321 if (personality_set
)
1324 personality (personality_orig
);
1326 warning (_("Error restoring address space randomization: %s"),
1327 safe_strerror (errno
));
1329 #endif /* HAVE_PERSONALITY */
1333 linux_nat_attach (struct target_ops
*ops
, const char *args
, int from_tty
)
1335 struct lwp_info
*lp
;
1338 volatile struct gdb_exception ex
;
1340 /* Make sure we report all signals during attach. */
1341 linux_nat_pass_signals (ops
, 0, NULL
);
1343 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
1345 linux_ops
->to_attach (ops
, args
, from_tty
);
1349 pid_t pid
= parse_pid_to_attach (args
);
1350 struct buffer buffer
;
1351 char *message
, *buffer_s
;
1353 message
= xstrdup (ex
.message
);
1354 make_cleanup (xfree
, message
);
1356 buffer_init (&buffer
);
1357 linux_ptrace_attach_fail_reason (pid
, &buffer
);
1359 buffer_grow_str0 (&buffer
, "");
1360 buffer_s
= buffer_finish (&buffer
);
1361 make_cleanup (xfree
, buffer_s
);
1363 if (*buffer_s
!= '\0')
1364 throw_error (ex
.error
, "warning: %s\n%s", buffer_s
, message
);
1366 throw_error (ex
.error
, "%s", message
);
1369 /* The ptrace base target adds the main thread with (pid,0,0)
1370 format. Decorate it with lwp info. */
1371 ptid
= ptid_build (ptid_get_pid (inferior_ptid
),
1372 ptid_get_pid (inferior_ptid
),
1374 thread_change_ptid (inferior_ptid
, ptid
);
1376 /* Add the initial process as the first LWP to the list. */
1377 lp
= add_initial_lwp (ptid
);
1379 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1381 if (!WIFSTOPPED (status
))
1383 if (WIFEXITED (status
))
1385 int exit_code
= WEXITSTATUS (status
);
1387 target_terminal_ours ();
1388 target_mourn_inferior ();
1390 error (_("Unable to attach: program exited normally."));
1392 error (_("Unable to attach: program exited with code %d."),
1395 else if (WIFSIGNALED (status
))
1397 enum gdb_signal signo
;
1399 target_terminal_ours ();
1400 target_mourn_inferior ();
1402 signo
= gdb_signal_from_host (WTERMSIG (status
));
1403 error (_("Unable to attach: program terminated with signal "
1405 gdb_signal_to_name (signo
),
1406 gdb_signal_to_string (signo
));
1409 internal_error (__FILE__
, __LINE__
,
1410 _("unexpected status %d for PID %ld"),
1411 status
, (long) ptid_get_lwp (ptid
));
1416 /* Save the wait status to report later. */
1418 if (debug_linux_nat
)
1419 fprintf_unfiltered (gdb_stdlog
,
1420 "LNA: waitpid %ld, saving status %s\n",
1421 (long) ptid_get_pid (lp
->ptid
), status_to_str (status
));
1423 lp
->status
= status
;
1425 if (target_can_async_p ())
1426 target_async (inferior_event_handler
, 0);
1429 /* Get pending status of LP. */
1431 get_pending_status (struct lwp_info
*lp
, int *status
)
1433 enum gdb_signal signo
= GDB_SIGNAL_0
;
1435 /* If we paused threads momentarily, we may have stored pending
1436 events in lp->status or lp->waitstatus (see stop_wait_callback),
1437 and GDB core hasn't seen any signal for those threads.
1438 Otherwise, the last signal reported to the core is found in the
1439 thread object's stop_signal.
1441 There's a corner case that isn't handled here at present. Only
1442 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1443 stop_signal make sense as a real signal to pass to the inferior.
1444 Some catchpoint related events, like
1445 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1446 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1447 those traps are debug API (ptrace in our case) related and
1448 induced; the inferior wouldn't see them if it wasn't being
1449 traced. Hence, we should never pass them to the inferior, even
1450 when set to pass state. Since this corner case isn't handled by
1451 infrun.c when proceeding with a signal, for consistency, neither
1452 do we handle it here (or elsewhere in the file we check for
1453 signal pass state). Normally SIGTRAP isn't set to pass state, so
1454 this is really a corner case. */
1456 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1457 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1458 else if (lp
->status
)
1459 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1460 else if (non_stop
&& !is_executing (lp
->ptid
))
1462 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1464 signo
= tp
->suspend
.stop_signal
;
1468 struct target_waitstatus last
;
1471 get_last_target_status (&last_ptid
, &last
);
1473 if (ptid_get_lwp (lp
->ptid
) == ptid_get_lwp (last_ptid
))
1475 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1477 signo
= tp
->suspend
.stop_signal
;
1483 if (signo
== GDB_SIGNAL_0
)
1485 if (debug_linux_nat
)
1486 fprintf_unfiltered (gdb_stdlog
,
1487 "GPT: lwp %s has no pending signal\n",
1488 target_pid_to_str (lp
->ptid
));
1490 else if (!signal_pass_state (signo
))
1492 if (debug_linux_nat
)
1493 fprintf_unfiltered (gdb_stdlog
,
1494 "GPT: lwp %s had signal %s, "
1495 "but it is in no pass state\n",
1496 target_pid_to_str (lp
->ptid
),
1497 gdb_signal_to_string (signo
));
1501 *status
= W_STOPCODE (gdb_signal_to_host (signo
));
1503 if (debug_linux_nat
)
1504 fprintf_unfiltered (gdb_stdlog
,
1505 "GPT: lwp %s has pending signal %s\n",
1506 target_pid_to_str (lp
->ptid
),
1507 gdb_signal_to_string (signo
));
1514 detach_callback (struct lwp_info
*lp
, void *data
)
1516 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1518 if (debug_linux_nat
&& lp
->status
)
1519 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1520 strsignal (WSTOPSIG (lp
->status
)),
1521 target_pid_to_str (lp
->ptid
));
1523 /* If there is a pending SIGSTOP, get rid of it. */
1526 if (debug_linux_nat
)
1527 fprintf_unfiltered (gdb_stdlog
,
1528 "DC: Sending SIGCONT to %s\n",
1529 target_pid_to_str (lp
->ptid
));
1531 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGCONT
);
1535 /* We don't actually detach from the LWP that has an id equal to the
1536 overall process id just yet. */
1537 if (ptid_get_lwp (lp
->ptid
) != ptid_get_pid (lp
->ptid
))
1541 /* Pass on any pending signal for this LWP. */
1542 get_pending_status (lp
, &status
);
1544 if (linux_nat_prepare_to_resume
!= NULL
)
1545 linux_nat_prepare_to_resume (lp
);
1547 if (ptrace (PTRACE_DETACH
, ptid_get_lwp (lp
->ptid
), 0,
1548 WSTOPSIG (status
)) < 0)
1549 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1550 safe_strerror (errno
));
1552 if (debug_linux_nat
)
1553 fprintf_unfiltered (gdb_stdlog
,
1554 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1555 target_pid_to_str (lp
->ptid
),
1556 strsignal (WSTOPSIG (status
)));
1558 delete_lwp (lp
->ptid
);
1565 linux_nat_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1569 struct lwp_info
*main_lwp
;
1571 pid
= ptid_get_pid (inferior_ptid
);
1573 /* Don't unregister from the event loop, as there may be other
1574 inferiors running. */
1576 /* Stop all threads before detaching. ptrace requires that the
1577 thread is stopped to sucessfully detach. */
1578 iterate_over_lwps (pid_to_ptid (pid
), stop_callback
, NULL
);
1579 /* ... and wait until all of them have reported back that
1580 they're no longer running. */
1581 iterate_over_lwps (pid_to_ptid (pid
), stop_wait_callback
, NULL
);
1583 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1585 /* Only the initial process should be left right now. */
1586 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid
)) == 1);
1588 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
1590 /* Pass on any pending signal for the last LWP. */
1591 if ((args
== NULL
|| *args
== '\0')
1592 && get_pending_status (main_lwp
, &status
) != -1
1593 && WIFSTOPPED (status
))
1597 /* Put the signal number in ARGS so that inf_ptrace_detach will
1598 pass it along with PTRACE_DETACH. */
1600 xsnprintf (tem
, 8, "%d", (int) WSTOPSIG (status
));
1602 if (debug_linux_nat
)
1603 fprintf_unfiltered (gdb_stdlog
,
1604 "LND: Sending signal %s to %s\n",
1606 target_pid_to_str (main_lwp
->ptid
));
1609 if (linux_nat_prepare_to_resume
!= NULL
)
1610 linux_nat_prepare_to_resume (main_lwp
);
1611 delete_lwp (main_lwp
->ptid
);
1613 if (forks_exist_p ())
1615 /* Multi-fork case. The current inferior_ptid is being detached
1616 from, but there are other viable forks to debug. Detach from
1617 the current fork, and context-switch to the first
1619 linux_fork_detach (args
, from_tty
);
1622 linux_ops
->to_detach (ops
, args
, from_tty
);
1628 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1632 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
1634 if (inf
->vfork_child
!= NULL
)
1636 if (debug_linux_nat
)
1637 fprintf_unfiltered (gdb_stdlog
,
1638 "RC: Not resuming %s (vfork parent)\n",
1639 target_pid_to_str (lp
->ptid
));
1641 else if (lp
->status
== 0
1642 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
1644 if (debug_linux_nat
)
1645 fprintf_unfiltered (gdb_stdlog
,
1646 "RC: Resuming sibling %s, %s, %s\n",
1647 target_pid_to_str (lp
->ptid
),
1648 (signo
!= GDB_SIGNAL_0
1649 ? strsignal (gdb_signal_to_host (signo
))
1651 step
? "step" : "resume");
1653 if (linux_nat_prepare_to_resume
!= NULL
)
1654 linux_nat_prepare_to_resume (lp
);
1655 linux_ops
->to_resume (linux_ops
,
1656 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
1660 lp
->stopped_by_watchpoint
= 0;
1664 if (debug_linux_nat
)
1665 fprintf_unfiltered (gdb_stdlog
,
1666 "RC: Not resuming sibling %s (has pending)\n",
1667 target_pid_to_str (lp
->ptid
));
1672 if (debug_linux_nat
)
1673 fprintf_unfiltered (gdb_stdlog
,
1674 "RC: Not resuming sibling %s (not stopped)\n",
1675 target_pid_to_str (lp
->ptid
));
1679 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1680 Resume LWP with the last stop signal, if it is in pass state. */
1683 linux_nat_resume_callback (struct lwp_info
*lp
, void *except
)
1685 enum gdb_signal signo
= GDB_SIGNAL_0
;
1692 struct thread_info
*thread
;
1694 thread
= find_thread_ptid (lp
->ptid
);
1697 signo
= thread
->suspend
.stop_signal
;
1698 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1702 resume_lwp (lp
, 0, signo
);
1707 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1710 lp
->last_resume_kind
= resume_stop
;
1715 resume_set_callback (struct lwp_info
*lp
, void *data
)
1718 lp
->last_resume_kind
= resume_continue
;
1723 linux_nat_resume (struct target_ops
*ops
,
1724 ptid_t ptid
, int step
, enum gdb_signal signo
)
1726 struct lwp_info
*lp
;
1729 if (debug_linux_nat
)
1730 fprintf_unfiltered (gdb_stdlog
,
1731 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1732 step
? "step" : "resume",
1733 target_pid_to_str (ptid
),
1734 (signo
!= GDB_SIGNAL_0
1735 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1736 target_pid_to_str (inferior_ptid
));
1738 /* A specific PTID means `step only this process id'. */
1739 resume_many
= (ptid_equal (minus_one_ptid
, ptid
)
1740 || ptid_is_pid (ptid
));
1742 /* Mark the lwps we're resuming as resumed. */
1743 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1745 /* See if it's the current inferior that should be handled
1748 lp
= find_lwp_pid (inferior_ptid
);
1750 lp
= find_lwp_pid (ptid
);
1751 gdb_assert (lp
!= NULL
);
1753 /* Remember if we're stepping. */
1755 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1757 /* If we have a pending wait status for this thread, there is no
1758 point in resuming the process. But first make sure that
1759 linux_nat_wait won't preemptively handle the event - we
1760 should never take this short-circuit if we are going to
1761 leave LP running, since we have skipped resuming all the
1762 other threads. This bit of code needs to be synchronized
1763 with linux_nat_wait. */
1765 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1768 && WSTOPSIG (lp
->status
)
1769 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1771 if (debug_linux_nat
)
1772 fprintf_unfiltered (gdb_stdlog
,
1773 "LLR: Not short circuiting for ignored "
1774 "status 0x%x\n", lp
->status
);
1776 /* FIXME: What should we do if we are supposed to continue
1777 this thread with a signal? */
1778 gdb_assert (signo
== GDB_SIGNAL_0
);
1779 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1784 if (lp
->status
|| lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1786 /* FIXME: What should we do if we are supposed to continue
1787 this thread with a signal? */
1788 gdb_assert (signo
== GDB_SIGNAL_0
);
1790 if (debug_linux_nat
)
1791 fprintf_unfiltered (gdb_stdlog
,
1792 "LLR: Short circuiting for status 0x%x\n",
1795 if (target_can_async_p ())
1797 target_async (inferior_event_handler
, 0);
1798 /* Tell the event loop we have something to process. */
1805 iterate_over_lwps (ptid
, linux_nat_resume_callback
, lp
);
1807 /* Convert to something the lower layer understands. */
1808 ptid
= pid_to_ptid (ptid_get_lwp (lp
->ptid
));
1810 if (linux_nat_prepare_to_resume
!= NULL
)
1811 linux_nat_prepare_to_resume (lp
);
1812 linux_ops
->to_resume (linux_ops
, ptid
, step
, signo
);
1813 lp
->stopped_by_watchpoint
= 0;
1816 if (debug_linux_nat
)
1817 fprintf_unfiltered (gdb_stdlog
,
1818 "LLR: %s %s, %s (resume event thread)\n",
1819 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1820 target_pid_to_str (ptid
),
1821 (signo
!= GDB_SIGNAL_0
1822 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1824 if (target_can_async_p ())
1825 target_async (inferior_event_handler
, 0);
1828 /* Send a signal to an LWP. */
1831 kill_lwp (int lwpid
, int signo
)
1833 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1834 fails, then we are not using nptl threads and we should be using kill. */
1836 #ifdef HAVE_TKILL_SYSCALL
1838 static int tkill_failed
;
1845 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1846 if (errno
!= ENOSYS
)
1853 return kill (lwpid
, signo
);
1856 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1857 event, check if the core is interested in it: if not, ignore the
1858 event, and keep waiting; otherwise, we need to toggle the LWP's
1859 syscall entry/exit status, since the ptrace event itself doesn't
1860 indicate it, and report the trap to higher layers. */
1863 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1865 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1866 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1867 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, lp
->ptid
);
1871 /* If we're stopping threads, there's a SIGSTOP pending, which
1872 makes it so that the LWP reports an immediate syscall return,
1873 followed by the SIGSTOP. Skip seeing that "return" using
1874 PTRACE_CONT directly, and let stop_wait_callback collect the
1875 SIGSTOP. Later when the thread is resumed, a new syscall
1876 entry event. If we didn't do this (and returned 0), we'd
1877 leave a syscall entry pending, and our caller, by using
1878 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1879 itself. Later, when the user re-resumes this LWP, we'd see
1880 another syscall entry event and we'd mistake it for a return.
1882 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1883 (leaving immediately with LWP->signalled set, without issuing
1884 a PTRACE_CONT), it would still be problematic to leave this
1885 syscall enter pending, as later when the thread is resumed,
1886 it would then see the same syscall exit mentioned above,
1887 followed by the delayed SIGSTOP, while the syscall didn't
1888 actually get to execute. It seems it would be even more
1889 confusing to the user. */
1891 if (debug_linux_nat
)
1892 fprintf_unfiltered (gdb_stdlog
,
1893 "LHST: ignoring syscall %d "
1894 "for LWP %ld (stopping threads), "
1895 "resuming with PTRACE_CONT for SIGSTOP\n",
1897 ptid_get_lwp (lp
->ptid
));
1899 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1900 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
1905 if (catch_syscall_enabled ())
1907 /* Always update the entry/return state, even if this particular
1908 syscall isn't interesting to the core now. In async mode,
1909 the user could install a new catchpoint for this syscall
1910 between syscall enter/return, and we'll need to know to
1911 report a syscall return if that happens. */
1912 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1913 ? TARGET_WAITKIND_SYSCALL_RETURN
1914 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1916 if (catching_syscall_number (syscall_number
))
1918 /* Alright, an event to report. */
1919 ourstatus
->kind
= lp
->syscall_state
;
1920 ourstatus
->value
.syscall_number
= syscall_number
;
1922 if (debug_linux_nat
)
1923 fprintf_unfiltered (gdb_stdlog
,
1924 "LHST: stopping for %s of syscall %d"
1927 == TARGET_WAITKIND_SYSCALL_ENTRY
1928 ? "entry" : "return",
1930 ptid_get_lwp (lp
->ptid
));
1934 if (debug_linux_nat
)
1935 fprintf_unfiltered (gdb_stdlog
,
1936 "LHST: ignoring %s of syscall %d "
1938 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1939 ? "entry" : "return",
1941 ptid_get_lwp (lp
->ptid
));
1945 /* If we had been syscall tracing, and hence used PT_SYSCALL
1946 before on this LWP, it could happen that the user removes all
1947 syscall catchpoints before we get to process this event.
1948 There are two noteworthy issues here:
1950 - When stopped at a syscall entry event, resuming with
1951 PT_STEP still resumes executing the syscall and reports a
1954 - Only PT_SYSCALL catches syscall enters. If we last
1955 single-stepped this thread, then this event can't be a
1956 syscall enter. If we last single-stepped this thread, this
1957 has to be a syscall exit.
1959 The points above mean that the next resume, be it PT_STEP or
1960 PT_CONTINUE, can not trigger a syscall trace event. */
1961 if (debug_linux_nat
)
1962 fprintf_unfiltered (gdb_stdlog
,
1963 "LHST: caught syscall event "
1964 "with no syscall catchpoints."
1965 " %d for LWP %ld, ignoring\n",
1967 ptid_get_lwp (lp
->ptid
));
1968 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1971 /* The core isn't interested in this event. For efficiency, avoid
1972 stopping all threads only to have the core resume them all again.
1973 Since we're not stopping threads, if we're still syscall tracing
1974 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1975 subsequent syscall. Simply resume using the inf-ptrace layer,
1976 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1978 /* Note that gdbarch_get_syscall_number may access registers, hence
1980 registers_changed ();
1981 if (linux_nat_prepare_to_resume
!= NULL
)
1982 linux_nat_prepare_to_resume (lp
);
1983 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
1984 lp
->step
, GDB_SIGNAL_0
);
1989 /* Handle a GNU/Linux extended wait response. If we see a clone
1990 event, we need to add the new LWP to our list (and not report the
1991 trap to higher layers). This function returns non-zero if the
1992 event should be ignored and we should wait again. If STOPPING is
1993 true, the new LWP remains stopped, otherwise it is continued. */
1996 linux_handle_extended_wait (struct lwp_info
*lp
, int status
,
1999 int pid
= ptid_get_lwp (lp
->ptid
);
2000 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
2001 int event
= status
>> 16;
2003 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
2004 || event
== PTRACE_EVENT_CLONE
)
2006 unsigned long new_pid
;
2009 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
2011 /* If we haven't already seen the new PID stop, wait for it now. */
2012 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
2014 /* The new child has a pending SIGSTOP. We can't affect it until it
2015 hits the SIGSTOP, but we're already attached. */
2016 ret
= my_waitpid (new_pid
, &status
,
2017 (event
== PTRACE_EVENT_CLONE
) ? __WCLONE
: 0);
2019 perror_with_name (_("waiting for new child"));
2020 else if (ret
!= new_pid
)
2021 internal_error (__FILE__
, __LINE__
,
2022 _("wait returned unexpected PID %d"), ret
);
2023 else if (!WIFSTOPPED (status
))
2024 internal_error (__FILE__
, __LINE__
,
2025 _("wait returned unexpected status 0x%x"), status
);
2028 ourstatus
->value
.related_pid
= ptid_build (new_pid
, new_pid
, 0);
2030 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
2032 /* The arch-specific native code may need to know about new
2033 forks even if those end up never mapped to an
2035 if (linux_nat_new_fork
!= NULL
)
2036 linux_nat_new_fork (lp
, new_pid
);
2039 if (event
== PTRACE_EVENT_FORK
2040 && linux_fork_checkpointing_p (ptid_get_pid (lp
->ptid
)))
2042 /* Handle checkpointing by linux-fork.c here as a special
2043 case. We don't want the follow-fork-mode or 'catch fork'
2044 to interfere with this. */
2046 /* This won't actually modify the breakpoint list, but will
2047 physically remove the breakpoints from the child. */
2048 detach_breakpoints (ptid_build (new_pid
, new_pid
, 0));
2050 /* Retain child fork in ptrace (stopped) state. */
2051 if (!find_fork_pid (new_pid
))
2054 /* Report as spurious, so that infrun doesn't want to follow
2055 this fork. We're actually doing an infcall in
2057 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
2059 /* Report the stop to the core. */
2063 if (event
== PTRACE_EVENT_FORK
)
2064 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2065 else if (event
== PTRACE_EVENT_VFORK
)
2066 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2069 struct lwp_info
*new_lp
;
2071 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2073 if (debug_linux_nat
)
2074 fprintf_unfiltered (gdb_stdlog
,
2075 "LHEW: Got clone event "
2076 "from LWP %d, new child is LWP %ld\n",
2079 new_lp
= add_lwp (ptid_build (ptid_get_pid (lp
->ptid
), new_pid
, 0));
2081 new_lp
->stopped
= 1;
2083 if (WSTOPSIG (status
) != SIGSTOP
)
2085 /* This can happen if someone starts sending signals to
2086 the new thread before it gets a chance to run, which
2087 have a lower number than SIGSTOP (e.g. SIGUSR1).
2088 This is an unlikely case, and harder to handle for
2089 fork / vfork than for clone, so we do not try - but
2090 we handle it for clone events here. We'll send
2091 the other signal on to the thread below. */
2093 new_lp
->signalled
= 1;
2097 struct thread_info
*tp
;
2099 /* When we stop for an event in some other thread, and
2100 pull the thread list just as this thread has cloned,
2101 we'll have seen the new thread in the thread_db list
2102 before handling the CLONE event (glibc's
2103 pthread_create adds the new thread to the thread list
2104 before clone'ing, and has the kernel fill in the
2105 thread's tid on the clone call with
2106 CLONE_PARENT_SETTID). If that happened, and the core
2107 had requested the new thread to stop, we'll have
2108 killed it with SIGSTOP. But since SIGSTOP is not an
2109 RT signal, it can only be queued once. We need to be
2110 careful to not resume the LWP if we wanted it to
2111 stop. In that case, we'll leave the SIGSTOP pending.
2112 It will later be reported as GDB_SIGNAL_0. */
2113 tp
= find_thread_ptid (new_lp
->ptid
);
2114 if (tp
!= NULL
&& tp
->stop_requested
)
2115 new_lp
->last_resume_kind
= resume_stop
;
2122 /* Add the new thread to GDB's lists as soon as possible
2125 1) the frontend doesn't have to wait for a stop to
2128 2) we tag it with the correct running state. */
2130 /* If the thread_db layer is active, let it know about
2131 this new thread, and add it to GDB's list. */
2132 if (!thread_db_attach_lwp (new_lp
->ptid
))
2134 /* We're not using thread_db. Add it to GDB's
2136 target_post_attach (ptid_get_lwp (new_lp
->ptid
));
2137 add_thread (new_lp
->ptid
);
2142 set_running (new_lp
->ptid
, 1);
2143 set_executing (new_lp
->ptid
, 1);
2144 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2146 new_lp
->last_resume_kind
= resume_continue
;
2152 /* We created NEW_LP so it cannot yet contain STATUS. */
2153 gdb_assert (new_lp
->status
== 0);
2155 /* Save the wait status to report later. */
2156 if (debug_linux_nat
)
2157 fprintf_unfiltered (gdb_stdlog
,
2158 "LHEW: waitpid of new LWP %ld, "
2159 "saving status %s\n",
2160 (long) ptid_get_lwp (new_lp
->ptid
),
2161 status_to_str (status
));
2162 new_lp
->status
= status
;
2165 /* Note the need to use the low target ops to resume, to
2166 handle resuming with PT_SYSCALL if we have syscall
2170 new_lp
->resumed
= 1;
2174 gdb_assert (new_lp
->last_resume_kind
== resume_continue
);
2175 if (debug_linux_nat
)
2176 fprintf_unfiltered (gdb_stdlog
,
2177 "LHEW: resuming new LWP %ld\n",
2178 ptid_get_lwp (new_lp
->ptid
));
2179 if (linux_nat_prepare_to_resume
!= NULL
)
2180 linux_nat_prepare_to_resume (new_lp
);
2181 linux_ops
->to_resume (linux_ops
, pid_to_ptid (new_pid
),
2183 new_lp
->stopped
= 0;
2187 if (debug_linux_nat
)
2188 fprintf_unfiltered (gdb_stdlog
,
2189 "LHEW: resuming parent LWP %d\n", pid
);
2190 if (linux_nat_prepare_to_resume
!= NULL
)
2191 linux_nat_prepare_to_resume (lp
);
2192 linux_ops
->to_resume (linux_ops
,
2193 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
2202 if (event
== PTRACE_EVENT_EXEC
)
2204 if (debug_linux_nat
)
2205 fprintf_unfiltered (gdb_stdlog
,
2206 "LHEW: Got exec event from LWP %ld\n",
2207 ptid_get_lwp (lp
->ptid
));
2209 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2210 ourstatus
->value
.execd_pathname
2211 = xstrdup (linux_child_pid_to_exec_file (NULL
, pid
));
2216 if (event
== PTRACE_EVENT_VFORK_DONE
)
2218 if (current_inferior ()->waiting_for_vfork_done
)
2220 if (debug_linux_nat
)
2221 fprintf_unfiltered (gdb_stdlog
,
2222 "LHEW: Got expected PTRACE_EVENT_"
2223 "VFORK_DONE from LWP %ld: stopping\n",
2224 ptid_get_lwp (lp
->ptid
));
2226 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2230 if (debug_linux_nat
)
2231 fprintf_unfiltered (gdb_stdlog
,
2232 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2233 "from LWP %ld: resuming\n",
2234 ptid_get_lwp (lp
->ptid
));
2235 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2239 internal_error (__FILE__
, __LINE__
,
2240 _("unknown ptrace event %d"), event
);
2243 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2247 wait_lwp (struct lwp_info
*lp
)
2251 int thread_dead
= 0;
2254 gdb_assert (!lp
->stopped
);
2255 gdb_assert (lp
->status
== 0);
2257 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2258 block_child_signals (&prev_mask
);
2262 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2263 was right and we should just call sigsuspend. */
2265 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, WNOHANG
);
2266 if (pid
== -1 && errno
== ECHILD
)
2267 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, __WCLONE
| WNOHANG
);
2268 if (pid
== -1 && errno
== ECHILD
)
2270 /* The thread has previously exited. We need to delete it
2271 now because, for some vendor 2.4 kernels with NPTL
2272 support backported, there won't be an exit event unless
2273 it is the main thread. 2.6 kernels will report an exit
2274 event for each thread that exits, as expected. */
2276 if (debug_linux_nat
)
2277 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2278 target_pid_to_str (lp
->ptid
));
2283 /* Bugs 10970, 12702.
2284 Thread group leader may have exited in which case we'll lock up in
2285 waitpid if there are other threads, even if they are all zombies too.
2286 Basically, we're not supposed to use waitpid this way.
2287 __WCLONE is not applicable for the leader so we can't use that.
2288 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2289 process; it gets ESRCH both for the zombie and for running processes.
2291 As a workaround, check if we're waiting for the thread group leader and
2292 if it's a zombie, and avoid calling waitpid if it is.
2294 This is racy, what if the tgl becomes a zombie right after we check?
2295 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2296 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2298 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
)
2299 && linux_proc_pid_is_zombie (ptid_get_lwp (lp
->ptid
)))
2302 if (debug_linux_nat
)
2303 fprintf_unfiltered (gdb_stdlog
,
2304 "WL: Thread group leader %s vanished.\n",
2305 target_pid_to_str (lp
->ptid
));
2309 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2310 get invoked despite our caller had them intentionally blocked by
2311 block_child_signals. This is sensitive only to the loop of
2312 linux_nat_wait_1 and there if we get called my_waitpid gets called
2313 again before it gets to sigsuspend so we can safely let the handlers
2314 get executed here. */
2316 sigsuspend (&suspend_mask
);
2319 restore_child_signals_mask (&prev_mask
);
2323 gdb_assert (pid
== ptid_get_lwp (lp
->ptid
));
2325 if (debug_linux_nat
)
2327 fprintf_unfiltered (gdb_stdlog
,
2328 "WL: waitpid %s received %s\n",
2329 target_pid_to_str (lp
->ptid
),
2330 status_to_str (status
));
2333 /* Check if the thread has exited. */
2334 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2337 if (debug_linux_nat
)
2338 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2339 target_pid_to_str (lp
->ptid
));
2349 gdb_assert (WIFSTOPPED (status
));
2352 /* Handle GNU/Linux's syscall SIGTRAPs. */
2353 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2355 /* No longer need the sysgood bit. The ptrace event ends up
2356 recorded in lp->waitstatus if we care for it. We can carry
2357 on handling the event like a regular SIGTRAP from here
2359 status
= W_STOPCODE (SIGTRAP
);
2360 if (linux_handle_syscall_trap (lp
, 1))
2361 return wait_lwp (lp
);
2364 /* Handle GNU/Linux's extended waitstatus for trace events. */
2365 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2367 if (debug_linux_nat
)
2368 fprintf_unfiltered (gdb_stdlog
,
2369 "WL: Handling extended status 0x%06x\n",
2371 if (linux_handle_extended_wait (lp
, status
, 1))
2372 return wait_lwp (lp
);
2378 /* Send a SIGSTOP to LP. */
2381 stop_callback (struct lwp_info
*lp
, void *data
)
2383 if (!lp
->stopped
&& !lp
->signalled
)
2387 if (debug_linux_nat
)
2389 fprintf_unfiltered (gdb_stdlog
,
2390 "SC: kill %s **<SIGSTOP>**\n",
2391 target_pid_to_str (lp
->ptid
));
2394 ret
= kill_lwp (ptid_get_lwp (lp
->ptid
), SIGSTOP
);
2395 if (debug_linux_nat
)
2397 fprintf_unfiltered (gdb_stdlog
,
2398 "SC: lwp kill %d %s\n",
2400 errno
? safe_strerror (errno
) : "ERRNO-OK");
2404 gdb_assert (lp
->status
== 0);
2410 /* Request a stop on LWP. */
2413 linux_stop_lwp (struct lwp_info
*lwp
)
2415 stop_callback (lwp
, NULL
);
2418 /* Return non-zero if LWP PID has a pending SIGINT. */
2421 linux_nat_has_pending_sigint (int pid
)
2423 sigset_t pending
, blocked
, ignored
;
2425 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2427 if (sigismember (&pending
, SIGINT
)
2428 && !sigismember (&ignored
, SIGINT
))
2434 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2437 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2439 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2440 flag to consume the next one. */
2441 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2442 && WSTOPSIG (lp
->status
) == SIGINT
)
2445 lp
->ignore_sigint
= 1;
2450 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2451 This function is called after we know the LWP has stopped; if the LWP
2452 stopped before the expected SIGINT was delivered, then it will never have
2453 arrived. Also, if the signal was delivered to a shared queue and consumed
2454 by a different thread, it will never be delivered to this LWP. */
2457 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2459 if (!lp
->ignore_sigint
)
2462 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp
->ptid
)))
2464 if (debug_linux_nat
)
2465 fprintf_unfiltered (gdb_stdlog
,
2466 "MCIS: Clearing bogus flag for %s\n",
2467 target_pid_to_str (lp
->ptid
));
2468 lp
->ignore_sigint
= 0;
2472 /* Fetch the possible triggered data watchpoint info and store it in
2475 On some archs, like x86, that use debug registers to set
2476 watchpoints, it's possible that the way to know which watched
2477 address trapped, is to check the register that is used to select
2478 which address to watch. Problem is, between setting the watchpoint
2479 and reading back which data address trapped, the user may change
2480 the set of watchpoints, and, as a consequence, GDB changes the
2481 debug registers in the inferior. To avoid reading back a stale
2482 stopped-data-address when that happens, we cache in LP the fact
2483 that a watchpoint trapped, and the corresponding data address, as
2484 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2485 registers meanwhile, we have the cached data we can rely on. */
2488 save_sigtrap (struct lwp_info
*lp
)
2490 struct cleanup
*old_chain
;
2492 if (linux_ops
->to_stopped_by_watchpoint
== NULL
)
2494 lp
->stopped_by_watchpoint
= 0;
2498 old_chain
= save_inferior_ptid ();
2499 inferior_ptid
= lp
->ptid
;
2501 lp
->stopped_by_watchpoint
= linux_ops
->to_stopped_by_watchpoint (linux_ops
);
2503 if (lp
->stopped_by_watchpoint
)
2505 if (linux_ops
->to_stopped_data_address
!= NULL
)
2506 lp
->stopped_data_address_p
=
2507 linux_ops
->to_stopped_data_address (¤t_target
,
2508 &lp
->stopped_data_address
);
2510 lp
->stopped_data_address_p
= 0;
2513 do_cleanups (old_chain
);
2516 /* See save_sigtrap. */
2519 linux_nat_stopped_by_watchpoint (struct target_ops
*ops
)
2521 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2523 gdb_assert (lp
!= NULL
);
2525 return lp
->stopped_by_watchpoint
;
2529 linux_nat_stopped_data_address (struct target_ops
*ops
, CORE_ADDR
*addr_p
)
2531 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2533 gdb_assert (lp
!= NULL
);
2535 *addr_p
= lp
->stopped_data_address
;
2537 return lp
->stopped_data_address_p
;
2540 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2543 sigtrap_is_event (int status
)
2545 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2548 /* SIGTRAP-like events recognizer. */
2550 static int (*linux_nat_status_is_event
) (int status
) = sigtrap_is_event
;
2552 /* Check for SIGTRAP-like events in LP. */
2555 linux_nat_lp_status_is_event (struct lwp_info
*lp
)
2557 /* We check for lp->waitstatus in addition to lp->status, because we can
2558 have pending process exits recorded in lp->status
2559 and W_EXITCODE(0,0) == 0. We should probably have an additional
2560 lp->status_p flag. */
2562 return (lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
2563 && linux_nat_status_is_event (lp
->status
));
2566 /* Set alternative SIGTRAP-like events recognizer. If
2567 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2571 linux_nat_set_status_is_event (struct target_ops
*t
,
2572 int (*status_is_event
) (int status
))
2574 linux_nat_status_is_event
= status_is_event
;
2577 /* Wait until LP is stopped. */
2580 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2582 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2584 /* If this is a vfork parent, bail out, it is not going to report
2585 any SIGSTOP until the vfork is done with. */
2586 if (inf
->vfork_child
!= NULL
)
2593 status
= wait_lwp (lp
);
2597 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2598 && WSTOPSIG (status
) == SIGINT
)
2600 lp
->ignore_sigint
= 0;
2603 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2605 if (debug_linux_nat
)
2606 fprintf_unfiltered (gdb_stdlog
,
2607 "PTRACE_CONT %s, 0, 0 (%s) "
2608 "(discarding SIGINT)\n",
2609 target_pid_to_str (lp
->ptid
),
2610 errno
? safe_strerror (errno
) : "OK");
2612 return stop_wait_callback (lp
, NULL
);
2615 maybe_clear_ignore_sigint (lp
);
2617 if (WSTOPSIG (status
) != SIGSTOP
)
2619 /* The thread was stopped with a signal other than SIGSTOP. */
2623 if (debug_linux_nat
)
2624 fprintf_unfiltered (gdb_stdlog
,
2625 "SWC: Pending event %s in %s\n",
2626 status_to_str ((int) status
),
2627 target_pid_to_str (lp
->ptid
));
2629 /* Save the sigtrap event. */
2630 lp
->status
= status
;
2631 gdb_assert (lp
->signalled
);
2635 /* We caught the SIGSTOP that we intended to catch, so
2636 there's no SIGSTOP pending. */
2638 if (debug_linux_nat
)
2639 fprintf_unfiltered (gdb_stdlog
,
2640 "SWC: Delayed SIGSTOP caught for %s.\n",
2641 target_pid_to_str (lp
->ptid
));
2643 /* Reset SIGNALLED only after the stop_wait_callback call
2644 above as it does gdb_assert on SIGNALLED. */
2652 /* Return non-zero if LP has a wait status pending. */
2655 status_callback (struct lwp_info
*lp
, void *data
)
2657 /* Only report a pending wait status if we pretend that this has
2658 indeed been resumed. */
2662 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2664 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2665 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2666 0', so a clean process exit can not be stored pending in
2667 lp->status, it is indistinguishable from
2668 no-pending-status. */
2672 if (lp
->status
!= 0)
2678 /* Return non-zero if LP isn't stopped. */
2681 running_callback (struct lwp_info
*lp
, void *data
)
2683 return (!lp
->stopped
2684 || ((lp
->status
!= 0
2685 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2689 /* Count the LWP's that have had events. */
2692 count_events_callback (struct lwp_info
*lp
, void *data
)
2696 gdb_assert (count
!= NULL
);
2698 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2699 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2705 /* Select the LWP (if any) that is currently being single-stepped. */
2708 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2710 if (lp
->last_resume_kind
== resume_step
2717 /* Select the Nth LWP that has had a SIGTRAP event. */
2720 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2722 int *selector
= data
;
2724 gdb_assert (selector
!= NULL
);
2726 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2727 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2728 if ((*selector
)-- == 0)
2735 cancel_breakpoint (struct lwp_info
*lp
)
2737 /* Arrange for a breakpoint to be hit again later. We don't keep
2738 the SIGTRAP status and don't forward the SIGTRAP signal to the
2739 LWP. We will handle the current event, eventually we will resume
2740 this LWP, and this breakpoint will trap again.
2742 If we do not do this, then we run the risk that the user will
2743 delete or disable the breakpoint, but the LWP will have already
2746 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2747 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2750 pc
= regcache_read_pc (regcache
) - target_decr_pc_after_break (gdbarch
);
2751 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2753 if (debug_linux_nat
)
2754 fprintf_unfiltered (gdb_stdlog
,
2755 "CB: Push back breakpoint for %s\n",
2756 target_pid_to_str (lp
->ptid
));
2758 /* Back up the PC if necessary. */
2759 if (target_decr_pc_after_break (gdbarch
))
2760 regcache_write_pc (regcache
, pc
);
2768 cancel_breakpoints_callback (struct lwp_info
*lp
, void *data
)
2770 struct lwp_info
*event_lp
= data
;
2772 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2776 /* If a LWP other than the LWP that we're reporting an event for has
2777 hit a GDB breakpoint (as opposed to some random trap signal),
2778 then just arrange for it to hit it again later. We don't keep
2779 the SIGTRAP status and don't forward the SIGTRAP signal to the
2780 LWP. We will handle the current event, eventually we will resume
2781 all LWPs, and this one will get its breakpoint trap again.
2783 If we do not do this, then we run the risk that the user will
2784 delete or disable the breakpoint, but the LWP will have already
2787 if (linux_nat_lp_status_is_event (lp
)
2788 && cancel_breakpoint (lp
))
2789 /* Throw away the SIGTRAP. */
2795 /* Select one LWP out of those that have events pending. */
2798 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2801 int random_selector
;
2802 struct lwp_info
*event_lp
;
2804 /* Record the wait status for the original LWP. */
2805 (*orig_lp
)->status
= *status
;
2807 /* Give preference to any LWP that is being single-stepped. */
2808 event_lp
= iterate_over_lwps (filter
,
2809 select_singlestep_lwp_callback
, NULL
);
2810 if (event_lp
!= NULL
)
2812 if (debug_linux_nat
)
2813 fprintf_unfiltered (gdb_stdlog
,
2814 "SEL: Select single-step %s\n",
2815 target_pid_to_str (event_lp
->ptid
));
2819 /* No single-stepping LWP. Select one at random, out of those
2820 which have had SIGTRAP events. */
2822 /* First see how many SIGTRAP events we have. */
2823 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2825 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2826 random_selector
= (int)
2827 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2829 if (debug_linux_nat
&& num_events
> 1)
2830 fprintf_unfiltered (gdb_stdlog
,
2831 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2832 num_events
, random_selector
);
2834 event_lp
= iterate_over_lwps (filter
,
2835 select_event_lwp_callback
,
2839 if (event_lp
!= NULL
)
2841 /* Switch the event LWP. */
2842 *orig_lp
= event_lp
;
2843 *status
= event_lp
->status
;
2846 /* Flush the wait status for the event LWP. */
2847 (*orig_lp
)->status
= 0;
2850 /* Return non-zero if LP has been resumed. */
2853 resumed_callback (struct lwp_info
*lp
, void *data
)
2858 /* Stop an active thread, verify it still exists, then resume it. If
2859 the thread ends up with a pending status, then it is not resumed,
2860 and *DATA (really a pointer to int), is set. */
2863 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2865 int *new_pending_p
= data
;
2869 ptid_t ptid
= lp
->ptid
;
2871 stop_callback (lp
, NULL
);
2872 stop_wait_callback (lp
, NULL
);
2874 /* Resume if the lwp still exists, and the core wanted it
2876 lp
= find_lwp_pid (ptid
);
2879 if (lp
->last_resume_kind
== resume_stop
2882 /* The core wanted the LWP to stop. Even if it stopped
2883 cleanly (with SIGSTOP), leave the event pending. */
2884 if (debug_linux_nat
)
2885 fprintf_unfiltered (gdb_stdlog
,
2886 "SARC: core wanted LWP %ld stopped "
2887 "(leaving SIGSTOP pending)\n",
2888 ptid_get_lwp (lp
->ptid
));
2889 lp
->status
= W_STOPCODE (SIGSTOP
);
2892 if (lp
->status
== 0)
2894 if (debug_linux_nat
)
2895 fprintf_unfiltered (gdb_stdlog
,
2896 "SARC: re-resuming LWP %ld\n",
2897 ptid_get_lwp (lp
->ptid
));
2898 resume_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2902 if (debug_linux_nat
)
2903 fprintf_unfiltered (gdb_stdlog
,
2904 "SARC: not re-resuming LWP %ld "
2906 ptid_get_lwp (lp
->ptid
));
2915 /* Check if we should go on and pass this event to common code.
2916 Return the affected lwp if we are, or NULL otherwise. If we stop
2917 all lwps temporarily, we may end up with new pending events in some
2918 other lwp. In that case set *NEW_PENDING_P to true. */
2920 static struct lwp_info
*
2921 linux_nat_filter_event (int lwpid
, int status
, int *new_pending_p
)
2923 struct lwp_info
*lp
;
2927 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2929 /* Check for stop events reported by a process we didn't already
2930 know about - anything not already in our LWP list.
2932 If we're expecting to receive stopped processes after
2933 fork, vfork, and clone events, then we'll just add the
2934 new one to our list and go back to waiting for the event
2935 to be reported - the stopped process might be returned
2936 from waitpid before or after the event is.
2938 But note the case of a non-leader thread exec'ing after the
2939 leader having exited, and gone from our lists. The non-leader
2940 thread changes its tid to the tgid. */
2942 if (WIFSTOPPED (status
) && lp
== NULL
2943 && (WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 == PTRACE_EVENT_EXEC
))
2945 /* A multi-thread exec after we had seen the leader exiting. */
2946 if (debug_linux_nat
)
2947 fprintf_unfiltered (gdb_stdlog
,
2948 "LLW: Re-adding thread group leader LWP %d.\n",
2951 lp
= add_lwp (ptid_build (lwpid
, lwpid
, 0));
2954 add_thread (lp
->ptid
);
2957 if (WIFSTOPPED (status
) && !lp
)
2959 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2963 /* Make sure we don't report an event for the exit of an LWP not in
2964 our list, i.e. not part of the current process. This can happen
2965 if we detach from a program we originally forked and then it
2967 if (!WIFSTOPPED (status
) && !lp
)
2970 /* This LWP is stopped now. (And if dead, this prevents it from
2971 ever being continued.) */
2974 /* Handle GNU/Linux's syscall SIGTRAPs. */
2975 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2977 /* No longer need the sysgood bit. The ptrace event ends up
2978 recorded in lp->waitstatus if we care for it. We can carry
2979 on handling the event like a regular SIGTRAP from here
2981 status
= W_STOPCODE (SIGTRAP
);
2982 if (linux_handle_syscall_trap (lp
, 0))
2986 /* Handle GNU/Linux's extended waitstatus for trace events. */
2987 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2989 if (debug_linux_nat
)
2990 fprintf_unfiltered (gdb_stdlog
,
2991 "LLW: Handling extended status 0x%06x\n",
2993 if (linux_handle_extended_wait (lp
, status
, 0))
2997 if (linux_nat_status_is_event (status
))
3000 /* Check if the thread has exited. */
3001 if ((WIFEXITED (status
) || WIFSIGNALED (status
))
3002 && num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
3004 /* If this is the main thread, we must stop all threads and verify
3005 if they are still alive. This is because in the nptl thread model
3006 on Linux 2.4, there is no signal issued for exiting LWPs
3007 other than the main thread. We only get the main thread exit
3008 signal once all child threads have already exited. If we
3009 stop all the threads and use the stop_wait_callback to check
3010 if they have exited we can determine whether this signal
3011 should be ignored or whether it means the end of the debugged
3012 application, regardless of which threading model is being
3014 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
))
3016 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
3017 stop_and_resume_callback
, new_pending_p
);
3020 if (debug_linux_nat
)
3021 fprintf_unfiltered (gdb_stdlog
,
3022 "LLW: %s exited.\n",
3023 target_pid_to_str (lp
->ptid
));
3025 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
3027 /* If there is at least one more LWP, then the exit signal
3028 was not the end of the debugged application and should be
3035 /* Check if the current LWP has previously exited. In the nptl
3036 thread model, LWPs other than the main thread do not issue
3037 signals when they exit so we must check whenever the thread has
3038 stopped. A similar check is made in stop_wait_callback(). */
3039 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1 && !linux_thread_alive (lp
->ptid
))
3041 ptid_t ptid
= pid_to_ptid (ptid_get_pid (lp
->ptid
));
3043 if (debug_linux_nat
)
3044 fprintf_unfiltered (gdb_stdlog
,
3045 "LLW: %s exited.\n",
3046 target_pid_to_str (lp
->ptid
));
3050 /* Make sure there is at least one thread running. */
3051 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
3053 /* Discard the event. */
3057 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3058 an attempt to stop an LWP. */
3060 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3062 if (debug_linux_nat
)
3063 fprintf_unfiltered (gdb_stdlog
,
3064 "LLW: Delayed SIGSTOP caught for %s.\n",
3065 target_pid_to_str (lp
->ptid
));
3069 if (lp
->last_resume_kind
!= resume_stop
)
3071 /* This is a delayed SIGSTOP. */
3073 registers_changed ();
3075 if (linux_nat_prepare_to_resume
!= NULL
)
3076 linux_nat_prepare_to_resume (lp
);
3077 linux_ops
->to_resume (linux_ops
,
3078 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3079 lp
->step
, GDB_SIGNAL_0
);
3080 if (debug_linux_nat
)
3081 fprintf_unfiltered (gdb_stdlog
,
3082 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3084 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3085 target_pid_to_str (lp
->ptid
));
3088 gdb_assert (lp
->resumed
);
3090 /* Discard the event. */
3095 /* Make sure we don't report a SIGINT that we have already displayed
3096 for another thread. */
3097 if (lp
->ignore_sigint
3098 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3100 if (debug_linux_nat
)
3101 fprintf_unfiltered (gdb_stdlog
,
3102 "LLW: Delayed SIGINT caught for %s.\n",
3103 target_pid_to_str (lp
->ptid
));
3105 /* This is a delayed SIGINT. */
3106 lp
->ignore_sigint
= 0;
3108 registers_changed ();
3109 if (linux_nat_prepare_to_resume
!= NULL
)
3110 linux_nat_prepare_to_resume (lp
);
3111 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3112 lp
->step
, GDB_SIGNAL_0
);
3113 if (debug_linux_nat
)
3114 fprintf_unfiltered (gdb_stdlog
,
3115 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3117 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3118 target_pid_to_str (lp
->ptid
));
3121 gdb_assert (lp
->resumed
);
3123 /* Discard the event. */
3127 /* An interesting event. */
3129 lp
->status
= status
;
3133 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3134 their exits until all other threads in the group have exited. */
3137 check_zombie_leaders (void)
3139 struct inferior
*inf
;
3143 struct lwp_info
*leader_lp
;
3148 leader_lp
= find_lwp_pid (pid_to_ptid (inf
->pid
));
3149 if (leader_lp
!= NULL
3150 /* Check if there are other threads in the group, as we may
3151 have raced with the inferior simply exiting. */
3152 && num_lwps (inf
->pid
) > 1
3153 && linux_proc_pid_is_zombie (inf
->pid
))
3155 if (debug_linux_nat
)
3156 fprintf_unfiltered (gdb_stdlog
,
3157 "CZL: Thread group leader %d zombie "
3158 "(it exited, or another thread execd).\n",
3161 /* A leader zombie can mean one of two things:
3163 - It exited, and there's an exit status pending
3164 available, or only the leader exited (not the whole
3165 program). In the latter case, we can't waitpid the
3166 leader's exit status until all other threads are gone.
3168 - There are 3 or more threads in the group, and a thread
3169 other than the leader exec'd. On an exec, the Linux
3170 kernel destroys all other threads (except the execing
3171 one) in the thread group, and resets the execing thread's
3172 tid to the tgid. No exit notification is sent for the
3173 execing thread -- from the ptracer's perspective, it
3174 appears as though the execing thread just vanishes.
3175 Until we reap all other threads except the leader and the
3176 execing thread, the leader will be zombie, and the
3177 execing thread will be in `D (disc sleep)'. As soon as
3178 all other threads are reaped, the execing thread changes
3179 it's tid to the tgid, and the previous (zombie) leader
3180 vanishes, giving place to the "new" leader. We could try
3181 distinguishing the exit and exec cases, by waiting once
3182 more, and seeing if something comes out, but it doesn't
3183 sound useful. The previous leader _does_ go away, and
3184 we'll re-add the new one once we see the exec event
3185 (which is just the same as what would happen if the
3186 previous leader did exit voluntarily before some other
3189 if (debug_linux_nat
)
3190 fprintf_unfiltered (gdb_stdlog
,
3191 "CZL: Thread group leader %d vanished.\n",
3193 exit_lwp (leader_lp
);
3199 linux_nat_wait_1 (struct target_ops
*ops
,
3200 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3203 static sigset_t prev_mask
;
3204 enum resume_kind last_resume_kind
;
3205 struct lwp_info
*lp
;
3208 if (debug_linux_nat
)
3209 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3211 /* The first time we get here after starting a new inferior, we may
3212 not have added it to the LWP list yet - this is the earliest
3213 moment at which we know its PID. */
3214 if (ptid_is_pid (inferior_ptid
))
3216 /* Upgrade the main thread's ptid. */
3217 thread_change_ptid (inferior_ptid
,
3218 ptid_build (ptid_get_pid (inferior_ptid
),
3219 ptid_get_pid (inferior_ptid
), 0));
3221 lp
= add_initial_lwp (inferior_ptid
);
3225 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3226 block_child_signals (&prev_mask
);
3232 /* First check if there is a LWP with a wait status pending. */
3233 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3235 /* Any LWP in the PTID group that's been resumed will do. */
3236 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3239 if (debug_linux_nat
&& lp
->status
)
3240 fprintf_unfiltered (gdb_stdlog
,
3241 "LLW: Using pending wait status %s for %s.\n",
3242 status_to_str (lp
->status
),
3243 target_pid_to_str (lp
->ptid
));
3246 else if (ptid_lwp_p (ptid
))
3248 if (debug_linux_nat
)
3249 fprintf_unfiltered (gdb_stdlog
,
3250 "LLW: Waiting for specific LWP %s.\n",
3251 target_pid_to_str (ptid
));
3253 /* We have a specific LWP to check. */
3254 lp
= find_lwp_pid (ptid
);
3257 if (debug_linux_nat
&& lp
->status
)
3258 fprintf_unfiltered (gdb_stdlog
,
3259 "LLW: Using pending wait status %s for %s.\n",
3260 status_to_str (lp
->status
),
3261 target_pid_to_str (lp
->ptid
));
3263 /* We check for lp->waitstatus in addition to lp->status,
3264 because we can have pending process exits recorded in
3265 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3266 an additional lp->status_p flag. */
3267 if (lp
->status
== 0 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3271 if (!target_can_async_p ())
3273 /* Causes SIGINT to be passed on to the attached process. */
3277 /* But if we don't find a pending event, we'll have to wait. */
3283 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3286 - If the thread group leader exits while other threads in the
3287 thread group still exist, waitpid(TGID, ...) hangs. That
3288 waitpid won't return an exit status until the other threads
3289 in the group are reapped.
3291 - When a non-leader thread execs, that thread just vanishes
3292 without reporting an exit (so we'd hang if we waited for it
3293 explicitly in that case). The exec event is reported to
3297 lwpid
= my_waitpid (-1, &status
, __WCLONE
| WNOHANG
);
3298 if (lwpid
== 0 || (lwpid
== -1 && errno
== ECHILD
))
3299 lwpid
= my_waitpid (-1, &status
, WNOHANG
);
3301 if (debug_linux_nat
)
3302 fprintf_unfiltered (gdb_stdlog
,
3303 "LNW: waitpid(-1, ...) returned %d, %s\n",
3304 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3308 /* If this is true, then we paused LWPs momentarily, and may
3309 now have pending events to handle. */
3312 if (debug_linux_nat
)
3314 fprintf_unfiltered (gdb_stdlog
,
3315 "LLW: waitpid %ld received %s\n",
3316 (long) lwpid
, status_to_str (status
));
3319 lp
= linux_nat_filter_event (lwpid
, status
, &new_pending
);
3321 /* STATUS is now no longer valid, use LP->STATUS instead. */
3324 if (lp
&& !ptid_match (lp
->ptid
, ptid
))
3326 gdb_assert (lp
->resumed
);
3328 if (debug_linux_nat
)
3330 "LWP %ld got an event %06x, leaving pending.\n",
3331 ptid_get_lwp (lp
->ptid
), lp
->status
);
3333 if (WIFSTOPPED (lp
->status
))
3335 if (WSTOPSIG (lp
->status
) != SIGSTOP
)
3337 /* Cancel breakpoint hits. The breakpoint may
3338 be removed before we fetch events from this
3339 process to report to the core. It is best
3340 not to assume the moribund breakpoints
3341 heuristic always handles these cases --- it
3342 could be too many events go through to the
3343 core before this one is handled. All-stop
3344 always cancels breakpoint hits in all
3347 && linux_nat_lp_status_is_event (lp
)
3348 && cancel_breakpoint (lp
))
3350 /* Throw away the SIGTRAP. */
3353 if (debug_linux_nat
)
3355 "LLW: LWP %ld hit a breakpoint while"
3356 " waiting for another process;"
3358 ptid_get_lwp (lp
->ptid
));
3364 else if (WIFEXITED (lp
->status
) || WIFSIGNALED (lp
->status
))
3366 if (debug_linux_nat
)
3368 "Process %ld exited while stopping LWPs\n",
3369 ptid_get_lwp (lp
->ptid
));
3371 /* This was the last lwp in the process. Since
3372 events are serialized to GDB core, and we can't
3373 report this one right now, but GDB core and the
3374 other target layers will want to be notified
3375 about the exit code/signal, leave the status
3376 pending for the next time we're able to report
3379 /* Dead LWP's aren't expected to reported a pending
3383 /* Store the pending event in the waitstatus as
3384 well, because W_EXITCODE(0,0) == 0. */
3385 store_waitstatus (&lp
->waitstatus
, lp
->status
);
3394 /* Some LWP now has a pending event. Go all the way
3395 back to check it. */
3401 /* We got an event to report to the core. */
3405 /* Retry until nothing comes out of waitpid. A single
3406 SIGCHLD can indicate more than one child stopped. */
3410 /* Check for zombie thread group leaders. Those can't be reaped
3411 until all other threads in the thread group are. */
3412 check_zombie_leaders ();
3414 /* If there are no resumed children left, bail. We'd be stuck
3415 forever in the sigsuspend call below otherwise. */
3416 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3418 if (debug_linux_nat
)
3419 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3421 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3423 if (!target_can_async_p ())
3424 clear_sigint_trap ();
3426 restore_child_signals_mask (&prev_mask
);
3427 return minus_one_ptid
;
3430 /* No interesting event to report to the core. */
3432 if (target_options
& TARGET_WNOHANG
)
3434 if (debug_linux_nat
)
3435 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3437 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3438 restore_child_signals_mask (&prev_mask
);
3439 return minus_one_ptid
;
3442 /* We shouldn't end up here unless we want to try again. */
3443 gdb_assert (lp
== NULL
);
3445 /* Block until we get an event reported with SIGCHLD. */
3446 sigsuspend (&suspend_mask
);
3449 if (!target_can_async_p ())
3450 clear_sigint_trap ();
3454 status
= lp
->status
;
3457 /* Don't report signals that GDB isn't interested in, such as
3458 signals that are neither printed nor stopped upon. Stopping all
3459 threads can be a bit time-consuming so if we want decent
3460 performance with heavily multi-threaded programs, especially when
3461 they're using a high frequency timer, we'd better avoid it if we
3464 if (WIFSTOPPED (status
))
3466 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3468 /* When using hardware single-step, we need to report every signal.
3469 Otherwise, signals in pass_mask may be short-circuited. */
3471 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
)))
3473 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3474 here? It is not clear we should. GDB may not expect
3475 other threads to run. On the other hand, not resuming
3476 newly attached threads may cause an unwanted delay in
3477 getting them running. */
3478 registers_changed ();
3479 if (linux_nat_prepare_to_resume
!= NULL
)
3480 linux_nat_prepare_to_resume (lp
);
3481 linux_ops
->to_resume (linux_ops
,
3482 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3484 if (debug_linux_nat
)
3485 fprintf_unfiltered (gdb_stdlog
,
3486 "LLW: %s %s, %s (preempt 'handle')\n",
3488 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3489 target_pid_to_str (lp
->ptid
),
3490 (signo
!= GDB_SIGNAL_0
3491 ? strsignal (gdb_signal_to_host (signo
))
3499 /* Only do the below in all-stop, as we currently use SIGINT
3500 to implement target_stop (see linux_nat_stop) in
3502 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3504 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3505 forwarded to the entire process group, that is, all LWPs
3506 will receive it - unless they're using CLONE_THREAD to
3507 share signals. Since we only want to report it once, we
3508 mark it as ignored for all LWPs except this one. */
3509 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid
)),
3510 set_ignore_sigint
, NULL
);
3511 lp
->ignore_sigint
= 0;
3514 maybe_clear_ignore_sigint (lp
);
3518 /* This LWP is stopped now. */
3521 if (debug_linux_nat
)
3522 fprintf_unfiltered (gdb_stdlog
, "LLW: Candidate event %s in %s.\n",
3523 status_to_str (status
), target_pid_to_str (lp
->ptid
));
3527 /* Now stop all other LWP's ... */
3528 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3530 /* ... and wait until all of them have reported back that
3531 they're no longer running. */
3532 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3534 /* If we're not waiting for a specific LWP, choose an event LWP
3535 from among those that have had events. Giving equal priority
3536 to all LWPs that have had events helps prevent
3538 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3539 select_event_lwp (ptid
, &lp
, &status
);
3541 /* Now that we've selected our final event LWP, cancel any
3542 breakpoints in other LWPs that have hit a GDB breakpoint.
3543 See the comment in cancel_breakpoints_callback to find out
3545 iterate_over_lwps (minus_one_ptid
, cancel_breakpoints_callback
, lp
);
3547 /* We'll need this to determine whether to report a SIGSTOP as
3548 TARGET_WAITKIND_0. Need to take a copy because
3549 resume_clear_callback clears it. */
3550 last_resume_kind
= lp
->last_resume_kind
;
3552 /* In all-stop, from the core's perspective, all LWPs are now
3553 stopped until a new resume action is sent over. */
3554 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3559 last_resume_kind
= lp
->last_resume_kind
;
3560 resume_clear_callback (lp
, NULL
);
3563 if (linux_nat_status_is_event (status
))
3565 if (debug_linux_nat
)
3566 fprintf_unfiltered (gdb_stdlog
,
3567 "LLW: trap ptid is %s.\n",
3568 target_pid_to_str (lp
->ptid
));
3571 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3573 *ourstatus
= lp
->waitstatus
;
3574 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3577 store_waitstatus (ourstatus
, status
);
3579 if (debug_linux_nat
)
3580 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3582 restore_child_signals_mask (&prev_mask
);
3584 if (last_resume_kind
== resume_stop
3585 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3586 && WSTOPSIG (status
) == SIGSTOP
)
3588 /* A thread that has been requested to stop by GDB with
3589 target_stop, and it stopped cleanly, so report as SIG0. The
3590 use of SIGSTOP is an implementation detail. */
3591 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3594 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3595 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3598 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3603 /* Resume LWPs that are currently stopped without any pending status
3604 to report, but are resumed from the core's perspective. */
3607 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3609 ptid_t
*wait_ptid_p
= data
;
3614 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3616 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3617 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3618 CORE_ADDR pc
= regcache_read_pc (regcache
);
3620 gdb_assert (is_executing (lp
->ptid
));
3622 /* Don't bother if there's a breakpoint at PC that we'd hit
3623 immediately, and we're not waiting for this LWP. */
3624 if (!ptid_match (lp
->ptid
, *wait_ptid_p
))
3626 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
3630 if (debug_linux_nat
)
3631 fprintf_unfiltered (gdb_stdlog
,
3632 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3633 target_pid_to_str (lp
->ptid
),
3634 paddress (gdbarch
, pc
),
3637 registers_changed ();
3638 if (linux_nat_prepare_to_resume
!= NULL
)
3639 linux_nat_prepare_to_resume (lp
);
3640 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3641 lp
->step
, GDB_SIGNAL_0
);
3643 lp
->stopped_by_watchpoint
= 0;
3650 linux_nat_wait (struct target_ops
*ops
,
3651 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3656 if (debug_linux_nat
)
3658 char *options_string
;
3660 options_string
= target_options_to_string (target_options
);
3661 fprintf_unfiltered (gdb_stdlog
,
3662 "linux_nat_wait: [%s], [%s]\n",
3663 target_pid_to_str (ptid
),
3665 xfree (options_string
);
3668 /* Flush the async file first. */
3669 if (target_can_async_p ())
3670 async_file_flush ();
3672 /* Resume LWPs that are currently stopped without any pending status
3673 to report, but are resumed from the core's perspective. LWPs get
3674 in this state if we find them stopping at a time we're not
3675 interested in reporting the event (target_wait on a
3676 specific_process, for example, see linux_nat_wait_1), and
3677 meanwhile the event became uninteresting. Don't bother resuming
3678 LWPs we're not going to wait for if they'd stop immediately. */
3680 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3682 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
3684 /* If we requested any event, and something came out, assume there
3685 may be more. If we requested a specific lwp or process, also
3686 assume there may be more. */
3687 if (target_can_async_p ()
3688 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3689 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3690 || !ptid_equal (ptid
, minus_one_ptid
)))
3693 /* Get ready for the next event. */
3694 if (target_can_async_p ())
3695 target_async (inferior_event_handler
, 0);
3701 kill_callback (struct lwp_info
*lp
, void *data
)
3703 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3706 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGKILL
);
3707 if (debug_linux_nat
)
3709 int save_errno
= errno
;
3711 fprintf_unfiltered (gdb_stdlog
,
3712 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3713 target_pid_to_str (lp
->ptid
),
3714 save_errno
? safe_strerror (save_errno
) : "OK");
3717 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3720 ptrace (PTRACE_KILL
, ptid_get_lwp (lp
->ptid
), 0, 0);
3721 if (debug_linux_nat
)
3723 int save_errno
= errno
;
3725 fprintf_unfiltered (gdb_stdlog
,
3726 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3727 target_pid_to_str (lp
->ptid
),
3728 save_errno
? safe_strerror (save_errno
) : "OK");
3735 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3739 /* We must make sure that there are no pending events (delayed
3740 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3741 program doesn't interfere with any following debugging session. */
3743 /* For cloned processes we must check both with __WCLONE and
3744 without, since the exit status of a cloned process isn't reported
3750 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, __WCLONE
);
3751 if (pid
!= (pid_t
) -1)
3753 if (debug_linux_nat
)
3754 fprintf_unfiltered (gdb_stdlog
,
3755 "KWC: wait %s received unknown.\n",
3756 target_pid_to_str (lp
->ptid
));
3757 /* The Linux kernel sometimes fails to kill a thread
3758 completely after PTRACE_KILL; that goes from the stop
3759 point in do_fork out to the one in
3760 get_signal_to_deliever and waits again. So kill it
3762 kill_callback (lp
, NULL
);
3765 while (pid
== ptid_get_lwp (lp
->ptid
));
3767 gdb_assert (pid
== -1 && errno
== ECHILD
);
3772 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, 0);
3773 if (pid
!= (pid_t
) -1)
3775 if (debug_linux_nat
)
3776 fprintf_unfiltered (gdb_stdlog
,
3777 "KWC: wait %s received unk.\n",
3778 target_pid_to_str (lp
->ptid
));
3779 /* See the call to kill_callback above. */
3780 kill_callback (lp
, NULL
);
3783 while (pid
== ptid_get_lwp (lp
->ptid
));
3785 gdb_assert (pid
== -1 && errno
== ECHILD
);
3790 linux_nat_kill (struct target_ops
*ops
)
3792 struct target_waitstatus last
;
3796 /* If we're stopped while forking and we haven't followed yet,
3797 kill the other task. We need to do this first because the
3798 parent will be sleeping if this is a vfork. */
3800 get_last_target_status (&last_ptid
, &last
);
3802 if (last
.kind
== TARGET_WAITKIND_FORKED
3803 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3805 ptrace (PT_KILL
, ptid_get_pid (last
.value
.related_pid
), 0, 0);
3808 /* Let the arch-specific native code know this process is
3810 linux_nat_forget_process (ptid_get_pid (last
.value
.related_pid
));
3813 if (forks_exist_p ())
3814 linux_fork_killall ();
3817 ptid_t ptid
= pid_to_ptid (ptid_get_pid (inferior_ptid
));
3819 /* Stop all threads before killing them, since ptrace requires
3820 that the thread is stopped to sucessfully PTRACE_KILL. */
3821 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3822 /* ... and wait until all of them have reported back that
3823 they're no longer running. */
3824 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3826 /* Kill all LWP's ... */
3827 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3829 /* ... and wait until we've flushed all events. */
3830 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3833 target_mourn_inferior ();
3837 linux_nat_mourn_inferior (struct target_ops
*ops
)
3839 int pid
= ptid_get_pid (inferior_ptid
);
3841 purge_lwp_list (pid
);
3843 if (! forks_exist_p ())
3844 /* Normal case, no other forks available. */
3845 linux_ops
->to_mourn_inferior (ops
);
3847 /* Multi-fork case. The current inferior_ptid has exited, but
3848 there are other viable forks to debug. Delete the exiting
3849 one and context-switch to the first available. */
3850 linux_fork_mourn_inferior ();
3852 /* Let the arch-specific native code know this process is gone. */
3853 linux_nat_forget_process (pid
);
3856 /* Convert a native/host siginfo object, into/from the siginfo in the
3857 layout of the inferiors' architecture. */
3860 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3864 if (linux_nat_siginfo_fixup
!= NULL
)
3865 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3867 /* If there was no callback, or the callback didn't do anything,
3868 then just do a straight memcpy. */
3872 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3874 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3878 static enum target_xfer_status
3879 linux_xfer_siginfo (struct target_ops
*ops
, enum target_object object
,
3880 const char *annex
, gdb_byte
*readbuf
,
3881 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3882 ULONGEST
*xfered_len
)
3886 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3888 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3889 gdb_assert (readbuf
|| writebuf
);
3891 pid
= ptid_get_lwp (inferior_ptid
);
3893 pid
= ptid_get_pid (inferior_ptid
);
3895 if (offset
> sizeof (siginfo
))
3896 return TARGET_XFER_E_IO
;
3899 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3901 return TARGET_XFER_E_IO
;
3903 /* When GDB is built as a 64-bit application, ptrace writes into
3904 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3905 inferior with a 64-bit GDB should look the same as debugging it
3906 with a 32-bit GDB, we need to convert it. GDB core always sees
3907 the converted layout, so any read/write will have to be done
3909 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3911 if (offset
+ len
> sizeof (siginfo
))
3912 len
= sizeof (siginfo
) - offset
;
3914 if (readbuf
!= NULL
)
3915 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3918 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3920 /* Convert back to ptrace layout before flushing it out. */
3921 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3924 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3926 return TARGET_XFER_E_IO
;
3930 return TARGET_XFER_OK
;
3933 static enum target_xfer_status
3934 linux_nat_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3935 const char *annex
, gdb_byte
*readbuf
,
3936 const gdb_byte
*writebuf
,
3937 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3939 struct cleanup
*old_chain
;
3940 enum target_xfer_status xfer
;
3942 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3943 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3944 offset
, len
, xfered_len
);
3946 /* The target is connected but no live inferior is selected. Pass
3947 this request down to a lower stratum (e.g., the executable
3949 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3950 return TARGET_XFER_EOF
;
3952 old_chain
= save_inferior_ptid ();
3954 if (ptid_lwp_p (inferior_ptid
))
3955 inferior_ptid
= pid_to_ptid (ptid_get_lwp (inferior_ptid
));
3957 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3958 offset
, len
, xfered_len
);
3960 do_cleanups (old_chain
);
3965 linux_thread_alive (ptid_t ptid
)
3969 gdb_assert (ptid_lwp_p (ptid
));
3971 /* Send signal 0 instead of anything ptrace, because ptracing a
3972 running thread errors out claiming that the thread doesn't
3974 err
= kill_lwp (ptid_get_lwp (ptid
), 0);
3976 if (debug_linux_nat
)
3977 fprintf_unfiltered (gdb_stdlog
,
3978 "LLTA: KILL(SIG0) %s (%s)\n",
3979 target_pid_to_str (ptid
),
3980 err
? safe_strerror (tmp_errno
) : "OK");
3989 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3991 return linux_thread_alive (ptid
);
3995 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3997 static char buf
[64];
3999 if (ptid_lwp_p (ptid
)
4000 && (ptid_get_pid (ptid
) != ptid_get_lwp (ptid
)
4001 || num_lwps (ptid_get_pid (ptid
)) > 1))
4003 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid_get_lwp (ptid
));
4007 return normal_pid_to_str (ptid
);
4011 linux_nat_thread_name (struct target_ops
*self
, struct thread_info
*thr
)
4013 int pid
= ptid_get_pid (thr
->ptid
);
4014 long lwp
= ptid_get_lwp (thr
->ptid
);
4015 #define FORMAT "/proc/%d/task/%ld/comm"
4016 char buf
[sizeof (FORMAT
) + 30];
4018 char *result
= NULL
;
4020 snprintf (buf
, sizeof (buf
), FORMAT
, pid
, lwp
);
4021 comm_file
= gdb_fopen_cloexec (buf
, "r");
4024 /* Not exported by the kernel, so we define it here. */
4026 static char line
[COMM_LEN
+ 1];
4028 if (fgets (line
, sizeof (line
), comm_file
))
4030 char *nl
= strchr (line
, '\n');
4047 /* Accepts an integer PID; Returns a string representing a file that
4048 can be opened to get the symbols for the child process. */
4051 linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
)
4053 static char buf
[PATH_MAX
];
4054 char name
[PATH_MAX
];
4056 xsnprintf (name
, PATH_MAX
, "/proc/%d/exe", pid
);
4057 memset (buf
, 0, PATH_MAX
);
4058 if (readlink (name
, buf
, PATH_MAX
- 1) <= 0)
4064 /* Records the thread's register state for the corefile note
4068 linux_nat_collect_thread_registers (const struct regcache
*regcache
,
4069 ptid_t ptid
, bfd
*obfd
,
4070 char *note_data
, int *note_size
,
4071 enum gdb_signal stop_signal
)
4073 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
4074 const struct regset
*regset
;
4076 gdb_gregset_t gregs
;
4077 gdb_fpregset_t fpregs
;
4079 core_regset_p
= gdbarch_regset_from_core_section_p (gdbarch
);
4082 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg",
4084 != NULL
&& regset
->collect_regset
!= NULL
)
4085 regset
->collect_regset (regset
, regcache
, -1, &gregs
, sizeof (gregs
));
4087 fill_gregset (regcache
, &gregs
, -1);
4089 note_data
= (char *) elfcore_write_prstatus
4090 (obfd
, note_data
, note_size
, ptid_get_lwp (ptid
),
4091 gdb_signal_to_host (stop_signal
), &gregs
);
4094 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg2",
4096 != NULL
&& regset
->collect_regset
!= NULL
)
4097 regset
->collect_regset (regset
, regcache
, -1, &fpregs
, sizeof (fpregs
));
4099 fill_fpregset (regcache
, &fpregs
, -1);
4101 note_data
= (char *) elfcore_write_prfpreg (obfd
, note_data
, note_size
,
4102 &fpregs
, sizeof (fpregs
));
4107 /* Fills the "to_make_corefile_note" target vector. Builds the note
4108 section for a corefile, and returns it in a malloc buffer. */
4111 linux_nat_make_corefile_notes (struct target_ops
*self
,
4112 bfd
*obfd
, int *note_size
)
4114 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4115 converted to gdbarch_core_regset_sections, this function can go away. */
4116 return linux_make_corefile_notes (target_gdbarch (), obfd
, note_size
,
4117 linux_nat_collect_thread_registers
);
4120 /* Implement the to_xfer_partial interface for memory reads using the /proc
4121 filesystem. Because we can use a single read() call for /proc, this
4122 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4123 but it doesn't support writes. */
4125 static enum target_xfer_status
4126 linux_proc_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4127 const char *annex
, gdb_byte
*readbuf
,
4128 const gdb_byte
*writebuf
,
4129 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
4135 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
4138 /* Don't bother for one word. */
4139 if (len
< 3 * sizeof (long))
4140 return TARGET_XFER_EOF
;
4142 /* We could keep this file open and cache it - possibly one per
4143 thread. That requires some juggling, but is even faster. */
4144 xsnprintf (filename
, sizeof filename
, "/proc/%d/mem",
4145 ptid_get_pid (inferior_ptid
));
4146 fd
= gdb_open_cloexec (filename
, O_RDONLY
| O_LARGEFILE
, 0);
4148 return TARGET_XFER_EOF
;
4150 /* If pread64 is available, use it. It's faster if the kernel
4151 supports it (only one syscall), and it's 64-bit safe even on
4152 32-bit platforms (for instance, SPARC debugging a SPARC64
4155 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
4157 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
4166 return TARGET_XFER_EOF
;
4170 return TARGET_XFER_OK
;
4175 /* Enumerate spufs IDs for process PID. */
4177 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
4179 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
4181 LONGEST written
= 0;
4184 struct dirent
*entry
;
4186 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
4187 dir
= opendir (path
);
4192 while ((entry
= readdir (dir
)) != NULL
)
4198 fd
= atoi (entry
->d_name
);
4202 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
4203 if (stat (path
, &st
) != 0)
4205 if (!S_ISDIR (st
.st_mode
))
4208 if (statfs (path
, &stfs
) != 0)
4210 if (stfs
.f_type
!= SPUFS_MAGIC
)
4213 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
4215 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
4225 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4226 object type, using the /proc file system. */
4228 static enum target_xfer_status
4229 linux_proc_xfer_spu (struct target_ops
*ops
, enum target_object object
,
4230 const char *annex
, gdb_byte
*readbuf
,
4231 const gdb_byte
*writebuf
,
4232 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
4237 int pid
= ptid_get_pid (inferior_ptid
);
4242 return TARGET_XFER_E_IO
;
4245 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4248 return TARGET_XFER_E_IO
;
4250 return TARGET_XFER_EOF
;
4253 *xfered_len
= (ULONGEST
) l
;
4254 return TARGET_XFER_OK
;
4259 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4260 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4262 return TARGET_XFER_E_IO
;
4265 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4268 return TARGET_XFER_EOF
;
4272 ret
= write (fd
, writebuf
, (size_t) len
);
4274 ret
= read (fd
, readbuf
, (size_t) len
);
4279 return TARGET_XFER_E_IO
;
4281 return TARGET_XFER_EOF
;
4284 *xfered_len
= (ULONGEST
) ret
;
4285 return TARGET_XFER_OK
;
4290 /* Parse LINE as a signal set and add its set bits to SIGS. */
4293 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4295 int len
= strlen (line
) - 1;
4299 if (line
[len
] != '\n')
4300 error (_("Could not parse signal set: %s"), line
);
4308 if (*p
>= '0' && *p
<= '9')
4310 else if (*p
>= 'a' && *p
<= 'f')
4311 digit
= *p
- 'a' + 10;
4313 error (_("Could not parse signal set: %s"), line
);
4318 sigaddset (sigs
, signum
+ 1);
4320 sigaddset (sigs
, signum
+ 2);
4322 sigaddset (sigs
, signum
+ 3);
4324 sigaddset (sigs
, signum
+ 4);
4330 /* Find process PID's pending signals from /proc/pid/status and set
4334 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4335 sigset_t
*blocked
, sigset_t
*ignored
)
4338 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4339 struct cleanup
*cleanup
;
4341 sigemptyset (pending
);
4342 sigemptyset (blocked
);
4343 sigemptyset (ignored
);
4344 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4345 procfile
= gdb_fopen_cloexec (fname
, "r");
4346 if (procfile
== NULL
)
4347 error (_("Could not open %s"), fname
);
4348 cleanup
= make_cleanup_fclose (procfile
);
4350 while (fgets (buffer
, PATH_MAX
, procfile
) != NULL
)
4352 /* Normal queued signals are on the SigPnd line in the status
4353 file. However, 2.6 kernels also have a "shared" pending
4354 queue for delivering signals to a thread group, so check for
4357 Unfortunately some Red Hat kernels include the shared pending
4358 queue but not the ShdPnd status field. */
4360 if (strncmp (buffer
, "SigPnd:\t", 8) == 0)
4361 add_line_to_sigset (buffer
+ 8, pending
);
4362 else if (strncmp (buffer
, "ShdPnd:\t", 8) == 0)
4363 add_line_to_sigset (buffer
+ 8, pending
);
4364 else if (strncmp (buffer
, "SigBlk:\t", 8) == 0)
4365 add_line_to_sigset (buffer
+ 8, blocked
);
4366 else if (strncmp (buffer
, "SigIgn:\t", 8) == 0)
4367 add_line_to_sigset (buffer
+ 8, ignored
);
4370 do_cleanups (cleanup
);
4373 static enum target_xfer_status
4374 linux_nat_xfer_osdata (struct target_ops
*ops
, enum target_object object
,
4375 const char *annex
, gdb_byte
*readbuf
,
4376 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4377 ULONGEST
*xfered_len
)
4379 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4381 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4382 if (*xfered_len
== 0)
4383 return TARGET_XFER_EOF
;
4385 return TARGET_XFER_OK
;
4388 static enum target_xfer_status
4389 linux_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4390 const char *annex
, gdb_byte
*readbuf
,
4391 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4392 ULONGEST
*xfered_len
)
4394 enum target_xfer_status xfer
;
4396 if (object
== TARGET_OBJECT_AUXV
)
4397 return memory_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4398 offset
, len
, xfered_len
);
4400 if (object
== TARGET_OBJECT_OSDATA
)
4401 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4402 offset
, len
, xfered_len
);
4404 if (object
== TARGET_OBJECT_SPU
)
4405 return linux_proc_xfer_spu (ops
, object
, annex
, readbuf
, writebuf
,
4406 offset
, len
, xfered_len
);
4408 /* GDB calculates all the addresses in possibly larget width of the address.
4409 Address width needs to be masked before its final use - either by
4410 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4412 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4414 if (object
== TARGET_OBJECT_MEMORY
)
4416 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
4418 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
4419 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
4422 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4423 offset
, len
, xfered_len
);
4424 if (xfer
!= TARGET_XFER_EOF
)
4427 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4428 offset
, len
, xfered_len
);
4432 cleanup_target_stop (void *arg
)
4434 ptid_t
*ptid
= (ptid_t
*) arg
;
4436 gdb_assert (arg
!= NULL
);
4439 target_resume (*ptid
, 0, GDB_SIGNAL_0
);
4442 static VEC(static_tracepoint_marker_p
) *
4443 linux_child_static_tracepoint_markers_by_strid (struct target_ops
*self
,
4446 char s
[IPA_CMD_BUF_SIZE
];
4447 struct cleanup
*old_chain
;
4448 int pid
= ptid_get_pid (inferior_ptid
);
4449 VEC(static_tracepoint_marker_p
) *markers
= NULL
;
4450 struct static_tracepoint_marker
*marker
= NULL
;
4452 ptid_t ptid
= ptid_build (pid
, 0, 0);
4457 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4458 s
[sizeof ("qTfSTM")] = 0;
4460 agent_run_command (pid
, s
, strlen (s
) + 1);
4462 old_chain
= make_cleanup (free_current_marker
, &marker
);
4463 make_cleanup (cleanup_target_stop
, &ptid
);
4468 marker
= XCNEW (struct static_tracepoint_marker
);
4472 parse_static_tracepoint_marker_definition (p
, &p
, marker
);
4474 if (strid
== NULL
|| strcmp (strid
, marker
->str_id
) == 0)
4476 VEC_safe_push (static_tracepoint_marker_p
,
4482 release_static_tracepoint_marker (marker
);
4483 memset (marker
, 0, sizeof (*marker
));
4486 while (*p
++ == ','); /* comma-separated list */
4488 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4489 s
[sizeof ("qTsSTM")] = 0;
4490 agent_run_command (pid
, s
, strlen (s
) + 1);
4494 do_cleanups (old_chain
);
4499 /* Create a prototype generic GNU/Linux target. The client can override
4500 it with local methods. */
4503 linux_target_install_ops (struct target_ops
*t
)
4505 t
->to_insert_fork_catchpoint
= linux_child_insert_fork_catchpoint
;
4506 t
->to_remove_fork_catchpoint
= linux_child_remove_fork_catchpoint
;
4507 t
->to_insert_vfork_catchpoint
= linux_child_insert_vfork_catchpoint
;
4508 t
->to_remove_vfork_catchpoint
= linux_child_remove_vfork_catchpoint
;
4509 t
->to_insert_exec_catchpoint
= linux_child_insert_exec_catchpoint
;
4510 t
->to_remove_exec_catchpoint
= linux_child_remove_exec_catchpoint
;
4511 t
->to_set_syscall_catchpoint
= linux_child_set_syscall_catchpoint
;
4512 t
->to_pid_to_exec_file
= linux_child_pid_to_exec_file
;
4513 t
->to_post_startup_inferior
= linux_child_post_startup_inferior
;
4514 t
->to_post_attach
= linux_child_post_attach
;
4515 t
->to_follow_fork
= linux_child_follow_fork
;
4516 t
->to_make_corefile_notes
= linux_nat_make_corefile_notes
;
4518 super_xfer_partial
= t
->to_xfer_partial
;
4519 t
->to_xfer_partial
= linux_xfer_partial
;
4521 t
->to_static_tracepoint_markers_by_strid
4522 = linux_child_static_tracepoint_markers_by_strid
;
4528 struct target_ops
*t
;
4530 t
= inf_ptrace_target ();
4531 linux_target_install_ops (t
);
4537 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4539 struct target_ops
*t
;
4541 t
= inf_ptrace_trad_target (register_u_offset
);
4542 linux_target_install_ops (t
);
4547 /* target_is_async_p implementation. */
4550 linux_nat_is_async_p (struct target_ops
*ops
)
4552 /* NOTE: palves 2008-03-21: We're only async when the user requests
4553 it explicitly with the "set target-async" command.
4554 Someday, linux will always be async. */
4555 return target_async_permitted
;
4558 /* target_can_async_p implementation. */
4561 linux_nat_can_async_p (struct target_ops
*ops
)
4563 /* NOTE: palves 2008-03-21: We're only async when the user requests
4564 it explicitly with the "set target-async" command.
4565 Someday, linux will always be async. */
4566 return target_async_permitted
;
4570 linux_nat_supports_non_stop (struct target_ops
*self
)
4575 /* True if we want to support multi-process. To be removed when GDB
4576 supports multi-exec. */
4578 int linux_multi_process
= 1;
4581 linux_nat_supports_multi_process (struct target_ops
*self
)
4583 return linux_multi_process
;
4587 linux_nat_supports_disable_randomization (struct target_ops
*self
)
4589 #ifdef HAVE_PERSONALITY
4596 static int async_terminal_is_ours
= 1;
4598 /* target_terminal_inferior implementation.
4600 This is a wrapper around child_terminal_inferior to add async support. */
4603 linux_nat_terminal_inferior (struct target_ops
*self
)
4605 if (!target_is_async_p ())
4607 /* Async mode is disabled. */
4608 child_terminal_inferior (self
);
4612 child_terminal_inferior (self
);
4614 /* Calls to target_terminal_*() are meant to be idempotent. */
4615 if (!async_terminal_is_ours
)
4618 delete_file_handler (input_fd
);
4619 async_terminal_is_ours
= 0;
4623 /* target_terminal_ours implementation.
4625 This is a wrapper around child_terminal_ours to add async support (and
4626 implement the target_terminal_ours vs target_terminal_ours_for_output
4627 distinction). child_terminal_ours is currently no different than
4628 child_terminal_ours_for_output.
4629 We leave target_terminal_ours_for_output alone, leaving it to
4630 child_terminal_ours_for_output. */
4633 linux_nat_terminal_ours (struct target_ops
*self
)
4635 if (!target_is_async_p ())
4637 /* Async mode is disabled. */
4638 child_terminal_ours (self
);
4642 /* GDB should never give the terminal to the inferior if the
4643 inferior is running in the background (run&, continue&, etc.),
4644 but claiming it sure should. */
4645 child_terminal_ours (self
);
4647 if (async_terminal_is_ours
)
4650 clear_sigint_trap ();
4651 add_file_handler (input_fd
, stdin_event_handler
, 0);
4652 async_terminal_is_ours
= 1;
4655 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4657 static void *async_client_context
;
4659 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4660 so we notice when any child changes state, and notify the
4661 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4662 above to wait for the arrival of a SIGCHLD. */
4665 sigchld_handler (int signo
)
4667 int old_errno
= errno
;
4669 if (debug_linux_nat
)
4670 ui_file_write_async_safe (gdb_stdlog
,
4671 "sigchld\n", sizeof ("sigchld\n") - 1);
4673 if (signo
== SIGCHLD
4674 && linux_nat_event_pipe
[0] != -1)
4675 async_file_mark (); /* Let the event loop know that there are
4676 events to handle. */
4681 /* Callback registered with the target events file descriptor. */
4684 handle_target_event (int error
, gdb_client_data client_data
)
4686 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4689 /* Create/destroy the target events pipe. Returns previous state. */
4692 linux_async_pipe (int enable
)
4694 int previous
= (linux_nat_event_pipe
[0] != -1);
4696 if (previous
!= enable
)
4700 /* Block child signals while we create/destroy the pipe, as
4701 their handler writes to it. */
4702 block_child_signals (&prev_mask
);
4706 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4707 internal_error (__FILE__
, __LINE__
,
4708 "creating event pipe failed.");
4710 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4711 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4715 close (linux_nat_event_pipe
[0]);
4716 close (linux_nat_event_pipe
[1]);
4717 linux_nat_event_pipe
[0] = -1;
4718 linux_nat_event_pipe
[1] = -1;
4721 restore_child_signals_mask (&prev_mask
);
4727 /* target_async implementation. */
4730 linux_nat_async (struct target_ops
*ops
,
4731 void (*callback
) (enum inferior_event_type event_type
,
4735 if (callback
!= NULL
)
4737 async_client_callback
= callback
;
4738 async_client_context
= context
;
4739 if (!linux_async_pipe (1))
4741 add_file_handler (linux_nat_event_pipe
[0],
4742 handle_target_event
, NULL
);
4743 /* There may be pending events to handle. Tell the event loop
4750 async_client_callback
= callback
;
4751 async_client_context
= context
;
4752 delete_file_handler (linux_nat_event_pipe
[0]);
4753 linux_async_pipe (0);
4758 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4762 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4766 if (debug_linux_nat
)
4767 fprintf_unfiltered (gdb_stdlog
,
4768 "LNSL: running -> suspending %s\n",
4769 target_pid_to_str (lwp
->ptid
));
4772 if (lwp
->last_resume_kind
== resume_stop
)
4774 if (debug_linux_nat
)
4775 fprintf_unfiltered (gdb_stdlog
,
4776 "linux-nat: already stopping LWP %ld at "
4778 ptid_get_lwp (lwp
->ptid
));
4782 stop_callback (lwp
, NULL
);
4783 lwp
->last_resume_kind
= resume_stop
;
4787 /* Already known to be stopped; do nothing. */
4789 if (debug_linux_nat
)
4791 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4792 fprintf_unfiltered (gdb_stdlog
,
4793 "LNSL: already stopped/stop_requested %s\n",
4794 target_pid_to_str (lwp
->ptid
));
4796 fprintf_unfiltered (gdb_stdlog
,
4797 "LNSL: already stopped/no "
4798 "stop_requested yet %s\n",
4799 target_pid_to_str (lwp
->ptid
));
4806 linux_nat_stop (struct target_ops
*self
, ptid_t ptid
)
4809 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4811 linux_ops
->to_stop (linux_ops
, ptid
);
4815 linux_nat_close (struct target_ops
*self
)
4817 /* Unregister from the event loop. */
4818 if (linux_nat_is_async_p (NULL
))
4819 linux_nat_async (NULL
, NULL
, 0);
4821 if (linux_ops
->to_close
)
4822 linux_ops
->to_close (linux_ops
);
4827 /* When requests are passed down from the linux-nat layer to the
4828 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4829 used. The address space pointer is stored in the inferior object,
4830 but the common code that is passed such ptid can't tell whether
4831 lwpid is a "main" process id or not (it assumes so). We reverse
4832 look up the "main" process id from the lwp here. */
4834 static struct address_space
*
4835 linux_nat_thread_address_space (struct target_ops
*t
, ptid_t ptid
)
4837 struct lwp_info
*lwp
;
4838 struct inferior
*inf
;
4841 pid
= ptid_get_lwp (ptid
);
4842 if (ptid_get_lwp (ptid
) == 0)
4844 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4846 lwp
= find_lwp_pid (ptid
);
4847 pid
= ptid_get_pid (lwp
->ptid
);
4851 /* A (pid,lwpid,0) ptid. */
4852 pid
= ptid_get_pid (ptid
);
4855 inf
= find_inferior_pid (pid
);
4856 gdb_assert (inf
!= NULL
);
4860 /* Return the cached value of the processor core for thread PTID. */
4863 linux_nat_core_of_thread (struct target_ops
*ops
, ptid_t ptid
)
4865 struct lwp_info
*info
= find_lwp_pid (ptid
);
4873 linux_nat_add_target (struct target_ops
*t
)
4875 /* Save the provided single-threaded target. We save this in a separate
4876 variable because another target we've inherited from (e.g. inf-ptrace)
4877 may have saved a pointer to T; we want to use it for the final
4878 process stratum target. */
4879 linux_ops_saved
= *t
;
4880 linux_ops
= &linux_ops_saved
;
4882 /* Override some methods for multithreading. */
4883 t
->to_create_inferior
= linux_nat_create_inferior
;
4884 t
->to_attach
= linux_nat_attach
;
4885 t
->to_detach
= linux_nat_detach
;
4886 t
->to_resume
= linux_nat_resume
;
4887 t
->to_wait
= linux_nat_wait
;
4888 t
->to_pass_signals
= linux_nat_pass_signals
;
4889 t
->to_xfer_partial
= linux_nat_xfer_partial
;
4890 t
->to_kill
= linux_nat_kill
;
4891 t
->to_mourn_inferior
= linux_nat_mourn_inferior
;
4892 t
->to_thread_alive
= linux_nat_thread_alive
;
4893 t
->to_pid_to_str
= linux_nat_pid_to_str
;
4894 t
->to_thread_name
= linux_nat_thread_name
;
4895 t
->to_has_thread_control
= tc_schedlock
;
4896 t
->to_thread_address_space
= linux_nat_thread_address_space
;
4897 t
->to_stopped_by_watchpoint
= linux_nat_stopped_by_watchpoint
;
4898 t
->to_stopped_data_address
= linux_nat_stopped_data_address
;
4900 t
->to_can_async_p
= linux_nat_can_async_p
;
4901 t
->to_is_async_p
= linux_nat_is_async_p
;
4902 t
->to_supports_non_stop
= linux_nat_supports_non_stop
;
4903 t
->to_async
= linux_nat_async
;
4904 t
->to_terminal_inferior
= linux_nat_terminal_inferior
;
4905 t
->to_terminal_ours
= linux_nat_terminal_ours
;
4907 super_close
= t
->to_close
;
4908 t
->to_close
= linux_nat_close
;
4910 /* Methods for non-stop support. */
4911 t
->to_stop
= linux_nat_stop
;
4913 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
4915 t
->to_supports_disable_randomization
4916 = linux_nat_supports_disable_randomization
;
4918 t
->to_core_of_thread
= linux_nat_core_of_thread
;
4920 /* We don't change the stratum; this target will sit at
4921 process_stratum and thread_db will set at thread_stratum. This
4922 is a little strange, since this is a multi-threaded-capable
4923 target, but we want to be on the stack below thread_db, and we
4924 also want to be used for single-threaded processes. */
4929 /* Register a method to call whenever a new thread is attached. */
4931 linux_nat_set_new_thread (struct target_ops
*t
,
4932 void (*new_thread
) (struct lwp_info
*))
4934 /* Save the pointer. We only support a single registered instance
4935 of the GNU/Linux native target, so we do not need to map this to
4937 linux_nat_new_thread
= new_thread
;
4940 /* See declaration in linux-nat.h. */
4943 linux_nat_set_new_fork (struct target_ops
*t
,
4944 linux_nat_new_fork_ftype
*new_fork
)
4946 /* Save the pointer. */
4947 linux_nat_new_fork
= new_fork
;
4950 /* See declaration in linux-nat.h. */
4953 linux_nat_set_forget_process (struct target_ops
*t
,
4954 linux_nat_forget_process_ftype
*fn
)
4956 /* Save the pointer. */
4957 linux_nat_forget_process_hook
= fn
;
4960 /* See declaration in linux-nat.h. */
4963 linux_nat_forget_process (pid_t pid
)
4965 if (linux_nat_forget_process_hook
!= NULL
)
4966 linux_nat_forget_process_hook (pid
);
4969 /* Register a method that converts a siginfo object between the layout
4970 that ptrace returns, and the layout in the architecture of the
4973 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4974 int (*siginfo_fixup
) (siginfo_t
*,
4978 /* Save the pointer. */
4979 linux_nat_siginfo_fixup
= siginfo_fixup
;
4982 /* Register a method to call prior to resuming a thread. */
4985 linux_nat_set_prepare_to_resume (struct target_ops
*t
,
4986 void (*prepare_to_resume
) (struct lwp_info
*))
4988 /* Save the pointer. */
4989 linux_nat_prepare_to_resume
= prepare_to_resume
;
4992 /* See linux-nat.h. */
4995 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4999 pid
= ptid_get_lwp (ptid
);
5001 pid
= ptid_get_pid (ptid
);
5004 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
5007 memset (siginfo
, 0, sizeof (*siginfo
));
5013 /* Provide a prototype to silence -Wmissing-prototypes. */
5014 extern initialize_file_ftype _initialize_linux_nat
;
5017 _initialize_linux_nat (void)
5019 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
5020 &debug_linux_nat
, _("\
5021 Set debugging of GNU/Linux lwp module."), _("\
5022 Show debugging of GNU/Linux lwp module."), _("\
5023 Enables printf debugging output."),
5025 show_debug_linux_nat
,
5026 &setdebuglist
, &showdebuglist
);
5028 /* Save this mask as the default. */
5029 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
5031 /* Install a SIGCHLD handler. */
5032 sigchld_action
.sa_handler
= sigchld_handler
;
5033 sigemptyset (&sigchld_action
.sa_mask
);
5034 sigchld_action
.sa_flags
= SA_RESTART
;
5036 /* Make it the default. */
5037 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
5039 /* Make sure we don't block SIGCHLD during a sigsuspend. */
5040 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
5041 sigdelset (&suspend_mask
, SIGCHLD
);
5043 sigemptyset (&blocked_mask
);
5045 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
5046 support read-only process state. */
5047 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
5048 | PTRACE_O_TRACEVFORKDONE
5049 | PTRACE_O_TRACEVFORK
5050 | PTRACE_O_TRACEFORK
5051 | PTRACE_O_TRACEEXEC
);
5055 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5056 the GNU/Linux Threads library and therefore doesn't really belong
5059 /* Read variable NAME in the target and return its value if found.
5060 Otherwise return zero. It is assumed that the type of the variable
5064 get_signo (const char *name
)
5066 struct bound_minimal_symbol ms
;
5069 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
5070 if (ms
.minsym
== NULL
)
5073 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
5074 sizeof (signo
)) != 0)
5080 /* Return the set of signals used by the threads library in *SET. */
5083 lin_thread_get_thread_signals (sigset_t
*set
)
5085 struct sigaction action
;
5086 int restart
, cancel
;
5088 sigemptyset (&blocked_mask
);
5091 restart
= get_signo ("__pthread_sig_restart");
5092 cancel
= get_signo ("__pthread_sig_cancel");
5094 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5095 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5096 not provide any way for the debugger to query the signal numbers -
5097 fortunately they don't change! */
5100 restart
= __SIGRTMIN
;
5103 cancel
= __SIGRTMIN
+ 1;
5105 sigaddset (set
, restart
);
5106 sigaddset (set
, cancel
);
5108 /* The GNU/Linux Threads library makes terminating threads send a
5109 special "cancel" signal instead of SIGCHLD. Make sure we catch
5110 those (to prevent them from terminating GDB itself, which is
5111 likely to be their default action) and treat them the same way as
5114 action
.sa_handler
= sigchld_handler
;
5115 sigemptyset (&action
.sa_mask
);
5116 action
.sa_flags
= SA_RESTART
;
5117 sigaction (cancel
, &action
, NULL
);
5119 /* We block the "cancel" signal throughout this code ... */
5120 sigaddset (&blocked_mask
, cancel
);
5121 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
5123 /* ... except during a sigsuspend. */
5124 sigdelset (&suspend_mask
, cancel
);