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"
27 #ifdef HAVE_TKILL_SYSCALL
29 #include <sys/syscall.h>
31 #include <sys/ptrace.h>
32 #include "linux-nat.h"
33 #include "nat/linux-ptrace.h"
34 #include "nat/linux-procfs.h"
35 #include "linux-fork.h"
36 #include "gdbthread.h"
40 #include "inf-child.h"
41 #include "inf-ptrace.h"
43 #include <sys/procfs.h> /* for elf_gregset etc. */
44 #include "elf-bfd.h" /* for elfcore_write_* */
45 #include "gregset.h" /* for gregset */
46 #include "gdbcore.h" /* for get_exec_file */
47 #include <ctype.h> /* for isdigit */
48 #include <sys/stat.h> /* for struct stat */
49 #include <fcntl.h> /* for O_RDONLY */
51 #include "event-loop.h"
52 #include "event-top.h"
54 #include <sys/types.h>
56 #include "xml-support.h"
60 #include "nat/linux-osdata.h"
61 #include "linux-tdep.h"
64 #include "tracepoint.h"
65 #include "exceptions.h"
67 #include "target-descriptions.h"
68 #include "filestuff.h"
72 #define SPUFS_MAGIC 0x23c9b64e
75 #ifdef HAVE_PERSONALITY
76 # include <sys/personality.h>
77 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
78 # define ADDR_NO_RANDOMIZE 0x0040000
80 #endif /* HAVE_PERSONALITY */
82 /* This comment documents high-level logic of this file.
84 Waiting for events in sync mode
85 ===============================
87 When waiting for an event in a specific thread, we just use waitpid, passing
88 the specific pid, and not passing WNOHANG.
90 When waiting for an event in all threads, waitpid is not quite good. Prior to
91 version 2.4, Linux can either wait for event in main thread, or in secondary
92 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
93 miss an event. The solution is to use non-blocking waitpid, together with
94 sigsuspend. First, we use non-blocking waitpid to get an event in the main
95 process, if any. Second, we use non-blocking waitpid with the __WCLONED
96 flag to check for events in cloned processes. If nothing is found, we use
97 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
98 happened to a child process -- and SIGCHLD will be delivered both for events
99 in main debugged process and in cloned processes. As soon as we know there's
100 an event, we get back to calling nonblocking waitpid with and without
103 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
104 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
105 blocked, the signal becomes pending and sigsuspend immediately
106 notices it and returns.
108 Waiting for events in async mode
109 ================================
111 In async mode, GDB should always be ready to handle both user input
112 and target events, so neither blocking waitpid nor sigsuspend are
113 viable options. Instead, we should asynchronously notify the GDB main
114 event loop whenever there's an unprocessed event from the target. We
115 detect asynchronous target events by handling SIGCHLD signals. To
116 notify the event loop about target events, the self-pipe trick is used
117 --- a pipe is registered as waitable event source in the event loop,
118 the event loop select/poll's on the read end of this pipe (as well on
119 other event sources, e.g., stdin), and the SIGCHLD handler writes a
120 byte to this pipe. This is more portable than relying on
121 pselect/ppoll, since on kernels that lack those syscalls, libc
122 emulates them with select/poll+sigprocmask, and that is racy
123 (a.k.a. plain broken).
125 Obviously, if we fail to notify the event loop if there's a target
126 event, it's bad. OTOH, if we notify the event loop when there's no
127 event from the target, linux_nat_wait will detect that there's no real
128 event to report, and return event of type TARGET_WAITKIND_IGNORE.
129 This is mostly harmless, but it will waste time and is better avoided.
131 The main design point is that every time GDB is outside linux-nat.c,
132 we have a SIGCHLD handler installed that is called when something
133 happens to the target and notifies the GDB event loop. Whenever GDB
134 core decides to handle the event, and calls into linux-nat.c, we
135 process things as in sync mode, except that the we never block in
138 While processing an event, we may end up momentarily blocked in
139 waitpid calls. Those waitpid calls, while blocking, are guarantied to
140 return quickly. E.g., in all-stop mode, before reporting to the core
141 that an LWP hit a breakpoint, all LWPs are stopped by sending them
142 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
143 Note that this is different from blocking indefinitely waiting for the
144 next event --- here, we're already handling an event.
149 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
150 signal is not entirely significant; we just need for a signal to be delivered,
151 so that we can intercept it. SIGSTOP's advantage is that it can not be
152 blocked. A disadvantage is that it is not a real-time signal, so it can only
153 be queued once; we do not keep track of other sources of SIGSTOP.
155 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
156 use them, because they have special behavior when the signal is generated -
157 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
158 kills the entire thread group.
160 A delivered SIGSTOP would stop the entire thread group, not just the thread we
161 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
162 cancel it (by PTRACE_CONT without passing SIGSTOP).
164 We could use a real-time signal instead. This would solve those problems; we
165 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
166 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
167 generates it, and there are races with trying to find a signal that is not
171 #define O_LARGEFILE 0
174 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
175 the use of the multi-threaded target. */
176 static struct target_ops
*linux_ops
;
177 static struct target_ops linux_ops_saved
;
179 /* The method to call, if any, when a new thread is attached. */
180 static void (*linux_nat_new_thread
) (struct lwp_info
*);
182 /* The method to call, if any, when a new fork is attached. */
183 static linux_nat_new_fork_ftype
*linux_nat_new_fork
;
185 /* The method to call, if any, when a process is no longer
187 static linux_nat_forget_process_ftype
*linux_nat_forget_process_hook
;
189 /* Hook to call prior to resuming a thread. */
190 static void (*linux_nat_prepare_to_resume
) (struct lwp_info
*);
192 /* The method to call, if any, when the siginfo object needs to be
193 converted between the layout returned by ptrace, and the layout in
194 the architecture of the inferior. */
195 static int (*linux_nat_siginfo_fixup
) (siginfo_t
*,
199 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
200 Called by our to_xfer_partial. */
201 static target_xfer_partial_ftype
*super_xfer_partial
;
203 /* The saved to_close method, inherited from inf-ptrace.c.
204 Called by our to_close. */
205 static void (*super_close
) (struct target_ops
*);
207 static unsigned int debug_linux_nat
;
209 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
210 struct cmd_list_element
*c
, const char *value
)
212 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
216 struct simple_pid_list
220 struct simple_pid_list
*next
;
222 struct simple_pid_list
*stopped_pids
;
224 /* Async mode support. */
226 /* The read/write ends of the pipe registered as waitable file in the
228 static int linux_nat_event_pipe
[2] = { -1, -1 };
230 /* Flush the event pipe. */
233 async_file_flush (void)
240 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
242 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
245 /* Put something (anything, doesn't matter what, or how much) in event
246 pipe, so that the select/poll in the event-loop realizes we have
247 something to process. */
250 async_file_mark (void)
254 /* It doesn't really matter what the pipe contains, as long we end
255 up with something in it. Might as well flush the previous
261 ret
= write (linux_nat_event_pipe
[1], "+", 1);
263 while (ret
== -1 && errno
== EINTR
);
265 /* Ignore EAGAIN. If the pipe is full, the event loop will already
266 be awakened anyway. */
269 static int kill_lwp (int lwpid
, int signo
);
271 static int stop_callback (struct lwp_info
*lp
, void *data
);
273 static void block_child_signals (sigset_t
*prev_mask
);
274 static void restore_child_signals_mask (sigset_t
*prev_mask
);
277 static struct lwp_info
*add_lwp (ptid_t ptid
);
278 static void purge_lwp_list (int pid
);
279 static void delete_lwp (ptid_t ptid
);
280 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
283 /* Trivial list manipulation functions to keep track of a list of
284 new stopped processes. */
286 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
288 struct simple_pid_list
*new_pid
= xmalloc (sizeof (struct simple_pid_list
));
291 new_pid
->status
= status
;
292 new_pid
->next
= *listp
;
297 in_pid_list_p (struct simple_pid_list
*list
, int pid
)
299 struct simple_pid_list
*p
;
301 for (p
= list
; p
!= NULL
; p
= p
->next
)
308 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
310 struct simple_pid_list
**p
;
312 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
313 if ((*p
)->pid
== pid
)
315 struct simple_pid_list
*next
= (*p
)->next
;
317 *statusp
= (*p
)->status
;
325 /* Initialize ptrace warnings and check for supported ptrace
326 features given PID. */
329 linux_init_ptrace (pid_t pid
)
331 linux_enable_event_reporting (pid
);
332 linux_ptrace_init_warnings ();
336 linux_child_post_attach (struct target_ops
*self
, int pid
)
338 linux_init_ptrace (pid
);
342 linux_child_post_startup_inferior (struct target_ops
*self
, ptid_t ptid
)
344 linux_init_ptrace (ptid_get_pid (ptid
));
347 /* Return the number of known LWPs in the tgid given by PID. */
355 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
356 if (ptid_get_pid (lp
->ptid
) == pid
)
362 /* Call delete_lwp with prototype compatible for make_cleanup. */
365 delete_lwp_cleanup (void *lp_voidp
)
367 struct lwp_info
*lp
= lp_voidp
;
369 delete_lwp (lp
->ptid
);
373 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
,
377 int parent_pid
, child_pid
;
379 has_vforked
= (inferior_thread ()->pending_follow
.kind
380 == TARGET_WAITKIND_VFORKED
);
381 parent_pid
= ptid_get_lwp (inferior_ptid
);
383 parent_pid
= ptid_get_pid (inferior_ptid
);
385 = ptid_get_pid (inferior_thread ()->pending_follow
.value
.related_pid
);
388 && !non_stop
/* Non-stop always resumes both branches. */
389 && (!target_is_async_p () || sync_execution
)
390 && !(follow_child
|| detach_fork
|| sched_multi
))
392 /* The parent stays blocked inside the vfork syscall until the
393 child execs or exits. If we don't let the child run, then
394 the parent stays blocked. If we're telling the parent to run
395 in the foreground, the user will not be able to ctrl-c to get
396 back the terminal, effectively hanging the debug session. */
397 fprintf_filtered (gdb_stderr
, _("\
398 Can not resume the parent process over vfork in the foreground while\n\
399 holding the child stopped. Try \"set detach-on-fork\" or \
400 \"set schedule-multiple\".\n"));
401 /* FIXME output string > 80 columns. */
407 struct lwp_info
*child_lp
= NULL
;
409 /* We're already attached to the parent, by default. */
411 /* Detach new forked process? */
414 struct cleanup
*old_chain
;
415 int status
= W_STOPCODE (0);
417 /* Before detaching from the child, remove all breakpoints
418 from it. If we forked, then this has already been taken
419 care of by infrun.c. If we vforked however, any
420 breakpoint inserted in the parent is visible in the
421 child, even those added while stopped in a vfork
422 catchpoint. This will remove the breakpoints from the
423 parent also, but they'll be reinserted below. */
426 /* keep breakpoints list in sync. */
427 remove_breakpoints_pid (ptid_get_pid (inferior_ptid
));
430 if (info_verbose
|| debug_linux_nat
)
432 target_terminal_ours ();
433 fprintf_filtered (gdb_stdlog
,
434 "Detaching after fork from "
435 "child process %d.\n",
439 old_chain
= save_inferior_ptid ();
440 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
442 child_lp
= add_lwp (inferior_ptid
);
443 child_lp
->stopped
= 1;
444 child_lp
->last_resume_kind
= resume_stop
;
445 make_cleanup (delete_lwp_cleanup
, child_lp
);
447 if (linux_nat_prepare_to_resume
!= NULL
)
448 linux_nat_prepare_to_resume (child_lp
);
450 /* When debugging an inferior in an architecture that supports
451 hardware single stepping on a kernel without commit
452 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
453 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
454 set if the parent process had them set.
455 To work around this, single step the child process
456 once before detaching to clear the flags. */
458 if (!gdbarch_software_single_step_p (target_thread_architecture
461 linux_disable_event_reporting (child_pid
);
462 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
463 perror_with_name (_("Couldn't do single step"));
464 if (my_waitpid (child_pid
, &status
, 0) < 0)
465 perror_with_name (_("Couldn't wait vfork process"));
468 if (WIFSTOPPED (status
))
472 signo
= WSTOPSIG (status
);
474 && !signal_pass_state (gdb_signal_from_host (signo
)))
476 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
479 do_cleanups (old_chain
);
483 struct inferior
*parent_inf
, *child_inf
;
484 struct cleanup
*old_chain
;
486 /* Add process to GDB's tables. */
487 child_inf
= add_inferior (child_pid
);
489 parent_inf
= current_inferior ();
490 child_inf
->attach_flag
= parent_inf
->attach_flag
;
491 copy_terminal_info (child_inf
, parent_inf
);
492 child_inf
->gdbarch
= parent_inf
->gdbarch
;
493 copy_inferior_target_desc_info (child_inf
, parent_inf
);
495 old_chain
= save_inferior_ptid ();
496 save_current_program_space ();
498 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
499 add_thread (inferior_ptid
);
500 child_lp
= add_lwp (inferior_ptid
);
501 child_lp
->stopped
= 1;
502 child_lp
->last_resume_kind
= resume_stop
;
503 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
505 /* If this is a vfork child, then the address-space is
506 shared with the parent. */
509 child_inf
->pspace
= parent_inf
->pspace
;
510 child_inf
->aspace
= parent_inf
->aspace
;
512 /* The parent will be frozen until the child is done
513 with the shared region. Keep track of the
515 child_inf
->vfork_parent
= parent_inf
;
516 child_inf
->pending_detach
= 0;
517 parent_inf
->vfork_child
= child_inf
;
518 parent_inf
->pending_detach
= 0;
522 child_inf
->aspace
= new_address_space ();
523 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
524 child_inf
->removable
= 1;
525 set_current_program_space (child_inf
->pspace
);
526 clone_program_space (child_inf
->pspace
, parent_inf
->pspace
);
528 /* Let the shared library layer (solib-svr4) learn about
529 this new process, relocate the cloned exec, pull in
530 shared libraries, and install the solib event
531 breakpoint. If a "cloned-VM" event was propagated
532 better throughout the core, this wouldn't be
534 solib_create_inferior_hook (0);
537 /* Let the thread_db layer learn about this new process. */
538 check_for_thread_db ();
540 do_cleanups (old_chain
);
545 struct lwp_info
*parent_lp
;
546 struct inferior
*parent_inf
;
548 parent_inf
= current_inferior ();
550 /* If we detached from the child, then we have to be careful
551 to not insert breakpoints in the parent until the child
552 is done with the shared memory region. However, if we're
553 staying attached to the child, then we can and should
554 insert breakpoints, so that we can debug it. A
555 subsequent child exec or exit is enough to know when does
556 the child stops using the parent's address space. */
557 parent_inf
->waiting_for_vfork_done
= detach_fork
;
558 parent_inf
->pspace
->breakpoints_not_allowed
= detach_fork
;
560 parent_lp
= find_lwp_pid (pid_to_ptid (parent_pid
));
561 gdb_assert (linux_supports_tracefork () >= 0);
563 if (linux_supports_tracevforkdone ())
566 fprintf_unfiltered (gdb_stdlog
,
567 "LCFF: waiting for VFORK_DONE on %d\n",
569 parent_lp
->stopped
= 1;
571 /* We'll handle the VFORK_DONE event like any other
572 event, in target_wait. */
576 /* We can't insert breakpoints until the child has
577 finished with the shared memory region. We need to
578 wait until that happens. Ideal would be to just
580 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
581 - waitpid (parent_pid, &status, __WALL);
582 However, most architectures can't handle a syscall
583 being traced on the way out if it wasn't traced on
586 We might also think to loop, continuing the child
587 until it exits or gets a SIGTRAP. One problem is
588 that the child might call ptrace with PTRACE_TRACEME.
590 There's no simple and reliable way to figure out when
591 the vforked child will be done with its copy of the
592 shared memory. We could step it out of the syscall,
593 two instructions, let it go, and then single-step the
594 parent once. When we have hardware single-step, this
595 would work; with software single-step it could still
596 be made to work but we'd have to be able to insert
597 single-step breakpoints in the child, and we'd have
598 to insert -just- the single-step breakpoint in the
599 parent. Very awkward.
601 In the end, the best we can do is to make sure it
602 runs for a little while. Hopefully it will be out of
603 range of any breakpoints we reinsert. Usually this
604 is only the single-step breakpoint at vfork's return
608 fprintf_unfiltered (gdb_stdlog
,
609 "LCFF: no VFORK_DONE "
610 "support, sleeping a bit\n");
614 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
615 and leave it pending. The next linux_nat_resume call
616 will notice a pending event, and bypasses actually
617 resuming the inferior. */
618 parent_lp
->status
= 0;
619 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
620 parent_lp
->stopped
= 1;
622 /* If we're in async mode, need to tell the event loop
623 there's something here to process. */
624 if (target_can_async_p ())
631 struct inferior
*parent_inf
, *child_inf
;
632 struct lwp_info
*child_lp
;
633 struct program_space
*parent_pspace
;
635 if (info_verbose
|| debug_linux_nat
)
637 target_terminal_ours ();
639 fprintf_filtered (gdb_stdlog
,
640 _("Attaching after process %d "
641 "vfork to child process %d.\n"),
642 parent_pid
, child_pid
);
644 fprintf_filtered (gdb_stdlog
,
645 _("Attaching after process %d "
646 "fork to child process %d.\n"),
647 parent_pid
, child_pid
);
650 /* Add the new inferior first, so that the target_detach below
651 doesn't unpush the target. */
653 child_inf
= add_inferior (child_pid
);
655 parent_inf
= current_inferior ();
656 child_inf
->attach_flag
= parent_inf
->attach_flag
;
657 copy_terminal_info (child_inf
, parent_inf
);
658 child_inf
->gdbarch
= parent_inf
->gdbarch
;
659 copy_inferior_target_desc_info (child_inf
, parent_inf
);
661 parent_pspace
= parent_inf
->pspace
;
663 /* If we're vforking, we want to hold on to the parent until the
664 child exits or execs. At child exec or exit time we can
665 remove the old breakpoints from the parent and detach or
666 resume debugging it. Otherwise, detach the parent now; we'll
667 want to reuse it's program/address spaces, but we can't set
668 them to the child before removing breakpoints from the
669 parent, otherwise, the breakpoints module could decide to
670 remove breakpoints from the wrong process (since they'd be
671 assigned to the same address space). */
675 gdb_assert (child_inf
->vfork_parent
== NULL
);
676 gdb_assert (parent_inf
->vfork_child
== NULL
);
677 child_inf
->vfork_parent
= parent_inf
;
678 child_inf
->pending_detach
= 0;
679 parent_inf
->vfork_child
= child_inf
;
680 parent_inf
->pending_detach
= detach_fork
;
681 parent_inf
->waiting_for_vfork_done
= 0;
683 else if (detach_fork
)
684 target_detach (NULL
, 0);
686 /* Note that the detach above makes PARENT_INF dangling. */
688 /* Add the child thread to the appropriate lists, and switch to
689 this new thread, before cloning the program space, and
690 informing the solib layer about this new process. */
692 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
693 add_thread (inferior_ptid
);
694 child_lp
= add_lwp (inferior_ptid
);
695 child_lp
->stopped
= 1;
696 child_lp
->last_resume_kind
= resume_stop
;
698 /* If this is a vfork child, then the address-space is shared
699 with the parent. If we detached from the parent, then we can
700 reuse the parent's program/address spaces. */
701 if (has_vforked
|| detach_fork
)
703 child_inf
->pspace
= parent_pspace
;
704 child_inf
->aspace
= child_inf
->pspace
->aspace
;
708 child_inf
->aspace
= new_address_space ();
709 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
710 child_inf
->removable
= 1;
711 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
712 set_current_program_space (child_inf
->pspace
);
713 clone_program_space (child_inf
->pspace
, parent_pspace
);
715 /* Let the shared library layer (solib-svr4) learn about
716 this new process, relocate the cloned exec, pull in
717 shared libraries, and install the solib event breakpoint.
718 If a "cloned-VM" event was propagated better throughout
719 the core, this wouldn't be required. */
720 solib_create_inferior_hook (0);
723 /* Let the thread_db layer learn about this new process. */
724 check_for_thread_db ();
732 linux_child_insert_fork_catchpoint (struct target_ops
*self
, int pid
)
734 return !linux_supports_tracefork ();
738 linux_child_remove_fork_catchpoint (struct target_ops
*self
, int pid
)
744 linux_child_insert_vfork_catchpoint (struct target_ops
*self
, int pid
)
746 return !linux_supports_tracefork ();
750 linux_child_remove_vfork_catchpoint (struct target_ops
*self
, int pid
)
756 linux_child_insert_exec_catchpoint (struct target_ops
*self
, int pid
)
758 return !linux_supports_tracefork ();
762 linux_child_remove_exec_catchpoint (struct target_ops
*self
, int pid
)
768 linux_child_set_syscall_catchpoint (struct target_ops
*self
,
769 int pid
, int needed
, int any_count
,
770 int table_size
, int *table
)
772 if (!linux_supports_tracesysgood ())
775 /* On GNU/Linux, we ignore the arguments. It means that we only
776 enable the syscall catchpoints, but do not disable them.
778 Also, we do not use the `table' information because we do not
779 filter system calls here. We let GDB do the logic for us. */
783 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
784 are processes sharing the same VM space. A multi-threaded process
785 is basically a group of such processes. However, such a grouping
786 is almost entirely a user-space issue; the kernel doesn't enforce
787 such a grouping at all (this might change in the future). In
788 general, we'll rely on the threads library (i.e. the GNU/Linux
789 Threads library) to provide such a grouping.
791 It is perfectly well possible to write a multi-threaded application
792 without the assistance of a threads library, by using the clone
793 system call directly. This module should be able to give some
794 rudimentary support for debugging such applications if developers
795 specify the CLONE_PTRACE flag in the clone system call, and are
796 using the Linux kernel 2.4 or above.
798 Note that there are some peculiarities in GNU/Linux that affect
801 - In general one should specify the __WCLONE flag to waitpid in
802 order to make it report events for any of the cloned processes
803 (and leave it out for the initial process). However, if a cloned
804 process has exited the exit status is only reported if the
805 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
806 we cannot use it since GDB must work on older systems too.
808 - When a traced, cloned process exits and is waited for by the
809 debugger, the kernel reassigns it to the original parent and
810 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
811 library doesn't notice this, which leads to the "zombie problem":
812 When debugged a multi-threaded process that spawns a lot of
813 threads will run out of processes, even if the threads exit,
814 because the "zombies" stay around. */
816 /* List of known LWPs. */
817 struct lwp_info
*lwp_list
;
820 /* Original signal mask. */
821 static sigset_t normal_mask
;
823 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
824 _initialize_linux_nat. */
825 static sigset_t suspend_mask
;
827 /* Signals to block to make that sigsuspend work. */
828 static sigset_t blocked_mask
;
830 /* SIGCHLD action. */
831 struct sigaction sigchld_action
;
833 /* Block child signals (SIGCHLD and linux threads signals), and store
834 the previous mask in PREV_MASK. */
837 block_child_signals (sigset_t
*prev_mask
)
839 /* Make sure SIGCHLD is blocked. */
840 if (!sigismember (&blocked_mask
, SIGCHLD
))
841 sigaddset (&blocked_mask
, SIGCHLD
);
843 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
846 /* Restore child signals mask, previously returned by
847 block_child_signals. */
850 restore_child_signals_mask (sigset_t
*prev_mask
)
852 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
855 /* Mask of signals to pass directly to the inferior. */
856 static sigset_t pass_mask
;
858 /* Update signals to pass to the inferior. */
860 linux_nat_pass_signals (struct target_ops
*self
,
861 int numsigs
, unsigned char *pass_signals
)
865 sigemptyset (&pass_mask
);
867 for (signo
= 1; signo
< NSIG
; signo
++)
869 int target_signo
= gdb_signal_from_host (signo
);
870 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
871 sigaddset (&pass_mask
, signo
);
877 /* Prototypes for local functions. */
878 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
879 static int linux_thread_alive (ptid_t ptid
);
880 static char *linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
);
884 /* Destroy and free LP. */
887 lwp_free (struct lwp_info
*lp
)
889 xfree (lp
->arch_private
);
893 /* Remove all LWPs belong to PID from the lwp list. */
896 purge_lwp_list (int pid
)
898 struct lwp_info
*lp
, *lpprev
, *lpnext
;
902 for (lp
= lwp_list
; lp
; lp
= lpnext
)
906 if (ptid_get_pid (lp
->ptid
) == pid
)
911 lpprev
->next
= lp
->next
;
920 /* Add the LWP specified by PTID to the list. PTID is the first LWP
921 in the process. Return a pointer to the structure describing the
924 This differs from add_lwp in that we don't let the arch specific
925 bits know about this new thread. Current clients of this callback
926 take the opportunity to install watchpoints in the new thread, and
927 we shouldn't do that for the first thread. If we're spawning a
928 child ("run"), the thread executes the shell wrapper first, and we
929 shouldn't touch it until it execs the program we want to debug.
930 For "attach", it'd be okay to call the callback, but it's not
931 necessary, because watchpoints can't yet have been inserted into
934 static struct lwp_info
*
935 add_initial_lwp (ptid_t ptid
)
939 gdb_assert (ptid_lwp_p (ptid
));
941 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
943 memset (lp
, 0, sizeof (struct lwp_info
));
945 lp
->last_resume_kind
= resume_continue
;
946 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
957 /* Add the LWP specified by PID to the list. Return a pointer to the
958 structure describing the new LWP. The LWP should already be
961 static struct lwp_info
*
962 add_lwp (ptid_t ptid
)
966 lp
= add_initial_lwp (ptid
);
968 /* Let the arch specific bits know about this new thread. Current
969 clients of this callback take the opportunity to install
970 watchpoints in the new thread. We don't do this for the first
971 thread though. See add_initial_lwp. */
972 if (linux_nat_new_thread
!= NULL
)
973 linux_nat_new_thread (lp
);
978 /* Remove the LWP specified by PID from the list. */
981 delete_lwp (ptid_t ptid
)
983 struct lwp_info
*lp
, *lpprev
;
987 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
988 if (ptid_equal (lp
->ptid
, ptid
))
995 lpprev
->next
= lp
->next
;
1002 /* Return a pointer to the structure describing the LWP corresponding
1003 to PID. If no corresponding LWP could be found, return NULL. */
1005 static struct lwp_info
*
1006 find_lwp_pid (ptid_t ptid
)
1008 struct lwp_info
*lp
;
1011 if (ptid_lwp_p (ptid
))
1012 lwp
= ptid_get_lwp (ptid
);
1014 lwp
= ptid_get_pid (ptid
);
1016 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
1017 if (lwp
== ptid_get_lwp (lp
->ptid
))
1023 /* Call CALLBACK with its second argument set to DATA for every LWP in
1024 the list. If CALLBACK returns 1 for a particular LWP, return a
1025 pointer to the structure describing that LWP immediately.
1026 Otherwise return NULL. */
1029 iterate_over_lwps (ptid_t filter
,
1030 int (*callback
) (struct lwp_info
*, void *),
1033 struct lwp_info
*lp
, *lpnext
;
1035 for (lp
= lwp_list
; lp
; lp
= lpnext
)
1039 if (ptid_match (lp
->ptid
, filter
))
1041 if ((*callback
) (lp
, data
))
1049 /* Update our internal state when changing from one checkpoint to
1050 another indicated by NEW_PTID. We can only switch single-threaded
1051 applications, so we only create one new LWP, and the previous list
1055 linux_nat_switch_fork (ptid_t new_ptid
)
1057 struct lwp_info
*lp
;
1059 purge_lwp_list (ptid_get_pid (inferior_ptid
));
1061 lp
= add_lwp (new_ptid
);
1064 /* This changes the thread's ptid while preserving the gdb thread
1065 num. Also changes the inferior pid, while preserving the
1067 thread_change_ptid (inferior_ptid
, new_ptid
);
1069 /* We've just told GDB core that the thread changed target id, but,
1070 in fact, it really is a different thread, with different register
1072 registers_changed ();
1075 /* Handle the exit of a single thread LP. */
1078 exit_lwp (struct lwp_info
*lp
)
1080 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1084 if (print_thread_events
)
1085 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
1087 delete_thread (lp
->ptid
);
1090 delete_lwp (lp
->ptid
);
1093 /* Wait for the LWP specified by LP, which we have just attached to.
1094 Returns a wait status for that LWP, to cache. */
1097 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
1100 pid_t new_pid
, pid
= ptid_get_lwp (ptid
);
1103 if (linux_proc_pid_is_stopped (pid
))
1105 if (debug_linux_nat
)
1106 fprintf_unfiltered (gdb_stdlog
,
1107 "LNPAW: Attaching to a stopped process\n");
1109 /* The process is definitely stopped. It is in a job control
1110 stop, unless the kernel predates the TASK_STOPPED /
1111 TASK_TRACED distinction, in which case it might be in a
1112 ptrace stop. Make sure it is in a ptrace stop; from there we
1113 can kill it, signal it, et cetera.
1115 First make sure there is a pending SIGSTOP. Since we are
1116 already attached, the process can not transition from stopped
1117 to running without a PTRACE_CONT; so we know this signal will
1118 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1119 probably already in the queue (unless this kernel is old
1120 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1121 is not an RT signal, it can only be queued once. */
1122 kill_lwp (pid
, SIGSTOP
);
1124 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1125 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1126 ptrace (PTRACE_CONT
, pid
, 0, 0);
1129 /* Make sure the initial process is stopped. The user-level threads
1130 layer might want to poke around in the inferior, and that won't
1131 work if things haven't stabilized yet. */
1132 new_pid
= my_waitpid (pid
, &status
, 0);
1133 if (new_pid
== -1 && errno
== ECHILD
)
1136 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
1138 /* Try again with __WCLONE to check cloned processes. */
1139 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
1143 gdb_assert (pid
== new_pid
);
1145 if (!WIFSTOPPED (status
))
1147 /* The pid we tried to attach has apparently just exited. */
1148 if (debug_linux_nat
)
1149 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1150 pid
, status_to_str (status
));
1154 if (WSTOPSIG (status
) != SIGSTOP
)
1157 if (debug_linux_nat
)
1158 fprintf_unfiltered (gdb_stdlog
,
1159 "LNPAW: Received %s after attaching\n",
1160 status_to_str (status
));
1166 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1167 the new LWP could not be attached, or 1 if we're already auto
1168 attached to this thread, but haven't processed the
1169 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1170 its existance, without considering it an error. */
1173 lin_lwp_attach_lwp (ptid_t ptid
)
1175 struct lwp_info
*lp
;
1178 gdb_assert (ptid_lwp_p (ptid
));
1180 lp
= find_lwp_pid (ptid
);
1181 lwpid
= ptid_get_lwp (ptid
);
1183 /* We assume that we're already attached to any LWP that has an id
1184 equal to the overall process id, and to any LWP that is already
1185 in our list of LWPs. If we're not seeing exit events from threads
1186 and we've had PID wraparound since we last tried to stop all threads,
1187 this assumption might be wrong; fortunately, this is very unlikely
1189 if (lwpid
!= ptid_get_pid (ptid
) && lp
== NULL
)
1191 int status
, cloned
= 0, signalled
= 0;
1193 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1195 if (linux_supports_tracefork ())
1197 /* If we haven't stopped all threads when we get here,
1198 we may have seen a thread listed in thread_db's list,
1199 but not processed the PTRACE_EVENT_CLONE yet. If
1200 that's the case, ignore this new thread, and let
1201 normal event handling discover it later. */
1202 if (in_pid_list_p (stopped_pids
, lwpid
))
1204 /* We've already seen this thread stop, but we
1205 haven't seen the PTRACE_EVENT_CLONE extended
1214 /* See if we've got a stop for this new child
1215 pending. If so, we're already attached. */
1216 new_pid
= my_waitpid (lwpid
, &status
, WNOHANG
);
1217 if (new_pid
== -1 && errno
== ECHILD
)
1218 new_pid
= my_waitpid (lwpid
, &status
, __WCLONE
| WNOHANG
);
1221 if (WIFSTOPPED (status
))
1222 add_to_pid_list (&stopped_pids
, lwpid
, status
);
1228 /* If we fail to attach to the thread, issue a warning,
1229 but continue. One way this can happen is if thread
1230 creation is interrupted; as of Linux kernel 2.6.19, a
1231 bug may place threads in the thread list and then fail
1233 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1234 safe_strerror (errno
));
1238 if (debug_linux_nat
)
1239 fprintf_unfiltered (gdb_stdlog
,
1240 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1241 target_pid_to_str (ptid
));
1243 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1244 if (!WIFSTOPPED (status
))
1247 lp
= add_lwp (ptid
);
1249 lp
->cloned
= cloned
;
1250 lp
->signalled
= signalled
;
1251 if (WSTOPSIG (status
) != SIGSTOP
)
1254 lp
->status
= status
;
1257 target_post_attach (ptid_get_lwp (lp
->ptid
));
1259 if (debug_linux_nat
)
1261 fprintf_unfiltered (gdb_stdlog
,
1262 "LLAL: waitpid %s received %s\n",
1263 target_pid_to_str (ptid
),
1264 status_to_str (status
));
1269 /* We assume that the LWP representing the original process is
1270 already stopped. Mark it as stopped in the data structure
1271 that the GNU/linux ptrace layer uses to keep track of
1272 threads. Note that this won't have already been done since
1273 the main thread will have, we assume, been stopped by an
1274 attach from a different layer. */
1276 lp
= add_lwp (ptid
);
1280 lp
->last_resume_kind
= resume_stop
;
1285 linux_nat_create_inferior (struct target_ops
*ops
,
1286 char *exec_file
, char *allargs
, char **env
,
1289 #ifdef HAVE_PERSONALITY
1290 int personality_orig
= 0, personality_set
= 0;
1291 #endif /* HAVE_PERSONALITY */
1293 /* The fork_child mechanism is synchronous and calls target_wait, so
1294 we have to mask the async mode. */
1296 #ifdef HAVE_PERSONALITY
1297 if (disable_randomization
)
1300 personality_orig
= personality (0xffffffff);
1301 if (errno
== 0 && !(personality_orig
& ADDR_NO_RANDOMIZE
))
1303 personality_set
= 1;
1304 personality (personality_orig
| ADDR_NO_RANDOMIZE
);
1306 if (errno
!= 0 || (personality_set
1307 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE
)))
1308 warning (_("Error disabling address space randomization: %s"),
1309 safe_strerror (errno
));
1311 #endif /* HAVE_PERSONALITY */
1313 /* Make sure we report all signals during startup. */
1314 linux_nat_pass_signals (ops
, 0, NULL
);
1316 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1318 #ifdef HAVE_PERSONALITY
1319 if (personality_set
)
1322 personality (personality_orig
);
1324 warning (_("Error restoring address space randomization: %s"),
1325 safe_strerror (errno
));
1327 #endif /* HAVE_PERSONALITY */
1331 linux_nat_attach (struct target_ops
*ops
, const char *args
, int from_tty
)
1333 struct lwp_info
*lp
;
1336 volatile struct gdb_exception ex
;
1338 /* Make sure we report all signals during attach. */
1339 linux_nat_pass_signals (ops
, 0, NULL
);
1341 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
1343 linux_ops
->to_attach (ops
, args
, from_tty
);
1347 pid_t pid
= parse_pid_to_attach (args
);
1348 struct buffer buffer
;
1349 char *message
, *buffer_s
;
1351 message
= xstrdup (ex
.message
);
1352 make_cleanup (xfree
, message
);
1354 buffer_init (&buffer
);
1355 linux_ptrace_attach_fail_reason (pid
, &buffer
);
1357 buffer_grow_str0 (&buffer
, "");
1358 buffer_s
= buffer_finish (&buffer
);
1359 make_cleanup (xfree
, buffer_s
);
1361 if (*buffer_s
!= '\0')
1362 throw_error (ex
.error
, "warning: %s\n%s", buffer_s
, message
);
1364 throw_error (ex
.error
, "%s", message
);
1367 /* The ptrace base target adds the main thread with (pid,0,0)
1368 format. Decorate it with lwp info. */
1369 ptid
= ptid_build (ptid_get_pid (inferior_ptid
),
1370 ptid_get_pid (inferior_ptid
),
1372 thread_change_ptid (inferior_ptid
, ptid
);
1374 /* Add the initial process as the first LWP to the list. */
1375 lp
= add_initial_lwp (ptid
);
1377 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1379 if (!WIFSTOPPED (status
))
1381 if (WIFEXITED (status
))
1383 int exit_code
= WEXITSTATUS (status
);
1385 target_terminal_ours ();
1386 target_mourn_inferior ();
1388 error (_("Unable to attach: program exited normally."));
1390 error (_("Unable to attach: program exited with code %d."),
1393 else if (WIFSIGNALED (status
))
1395 enum gdb_signal signo
;
1397 target_terminal_ours ();
1398 target_mourn_inferior ();
1400 signo
= gdb_signal_from_host (WTERMSIG (status
));
1401 error (_("Unable to attach: program terminated with signal "
1403 gdb_signal_to_name (signo
),
1404 gdb_signal_to_string (signo
));
1407 internal_error (__FILE__
, __LINE__
,
1408 _("unexpected status %d for PID %ld"),
1409 status
, (long) ptid_get_lwp (ptid
));
1414 /* Save the wait status to report later. */
1416 if (debug_linux_nat
)
1417 fprintf_unfiltered (gdb_stdlog
,
1418 "LNA: waitpid %ld, saving status %s\n",
1419 (long) ptid_get_pid (lp
->ptid
), status_to_str (status
));
1421 lp
->status
= status
;
1423 if (target_can_async_p ())
1424 target_async (inferior_event_handler
, 0);
1427 /* Get pending status of LP. */
1429 get_pending_status (struct lwp_info
*lp
, int *status
)
1431 enum gdb_signal signo
= GDB_SIGNAL_0
;
1433 /* If we paused threads momentarily, we may have stored pending
1434 events in lp->status or lp->waitstatus (see stop_wait_callback),
1435 and GDB core hasn't seen any signal for those threads.
1436 Otherwise, the last signal reported to the core is found in the
1437 thread object's stop_signal.
1439 There's a corner case that isn't handled here at present. Only
1440 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1441 stop_signal make sense as a real signal to pass to the inferior.
1442 Some catchpoint related events, like
1443 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1444 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1445 those traps are debug API (ptrace in our case) related and
1446 induced; the inferior wouldn't see them if it wasn't being
1447 traced. Hence, we should never pass them to the inferior, even
1448 when set to pass state. Since this corner case isn't handled by
1449 infrun.c when proceeding with a signal, for consistency, neither
1450 do we handle it here (or elsewhere in the file we check for
1451 signal pass state). Normally SIGTRAP isn't set to pass state, so
1452 this is really a corner case. */
1454 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1455 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1456 else if (lp
->status
)
1457 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1458 else if (non_stop
&& !is_executing (lp
->ptid
))
1460 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1462 signo
= tp
->suspend
.stop_signal
;
1466 struct target_waitstatus last
;
1469 get_last_target_status (&last_ptid
, &last
);
1471 if (ptid_get_lwp (lp
->ptid
) == ptid_get_lwp (last_ptid
))
1473 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1475 signo
= tp
->suspend
.stop_signal
;
1481 if (signo
== GDB_SIGNAL_0
)
1483 if (debug_linux_nat
)
1484 fprintf_unfiltered (gdb_stdlog
,
1485 "GPT: lwp %s has no pending signal\n",
1486 target_pid_to_str (lp
->ptid
));
1488 else if (!signal_pass_state (signo
))
1490 if (debug_linux_nat
)
1491 fprintf_unfiltered (gdb_stdlog
,
1492 "GPT: lwp %s had signal %s, "
1493 "but it is in no pass state\n",
1494 target_pid_to_str (lp
->ptid
),
1495 gdb_signal_to_string (signo
));
1499 *status
= W_STOPCODE (gdb_signal_to_host (signo
));
1501 if (debug_linux_nat
)
1502 fprintf_unfiltered (gdb_stdlog
,
1503 "GPT: lwp %s has pending signal %s\n",
1504 target_pid_to_str (lp
->ptid
),
1505 gdb_signal_to_string (signo
));
1512 detach_callback (struct lwp_info
*lp
, void *data
)
1514 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1516 if (debug_linux_nat
&& lp
->status
)
1517 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1518 strsignal (WSTOPSIG (lp
->status
)),
1519 target_pid_to_str (lp
->ptid
));
1521 /* If there is a pending SIGSTOP, get rid of it. */
1524 if (debug_linux_nat
)
1525 fprintf_unfiltered (gdb_stdlog
,
1526 "DC: Sending SIGCONT to %s\n",
1527 target_pid_to_str (lp
->ptid
));
1529 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGCONT
);
1533 /* We don't actually detach from the LWP that has an id equal to the
1534 overall process id just yet. */
1535 if (ptid_get_lwp (lp
->ptid
) != ptid_get_pid (lp
->ptid
))
1539 /* Pass on any pending signal for this LWP. */
1540 get_pending_status (lp
, &status
);
1542 if (linux_nat_prepare_to_resume
!= NULL
)
1543 linux_nat_prepare_to_resume (lp
);
1545 if (ptrace (PTRACE_DETACH
, ptid_get_lwp (lp
->ptid
), 0,
1546 WSTOPSIG (status
)) < 0)
1547 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1548 safe_strerror (errno
));
1550 if (debug_linux_nat
)
1551 fprintf_unfiltered (gdb_stdlog
,
1552 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1553 target_pid_to_str (lp
->ptid
),
1554 strsignal (WSTOPSIG (status
)));
1556 delete_lwp (lp
->ptid
);
1563 linux_nat_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1567 struct lwp_info
*main_lwp
;
1569 pid
= ptid_get_pid (inferior_ptid
);
1571 /* Don't unregister from the event loop, as there may be other
1572 inferiors running. */
1574 /* Stop all threads before detaching. ptrace requires that the
1575 thread is stopped to sucessfully detach. */
1576 iterate_over_lwps (pid_to_ptid (pid
), stop_callback
, NULL
);
1577 /* ... and wait until all of them have reported back that
1578 they're no longer running. */
1579 iterate_over_lwps (pid_to_ptid (pid
), stop_wait_callback
, NULL
);
1581 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1583 /* Only the initial process should be left right now. */
1584 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid
)) == 1);
1586 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
1588 /* Pass on any pending signal for the last LWP. */
1589 if ((args
== NULL
|| *args
== '\0')
1590 && get_pending_status (main_lwp
, &status
) != -1
1591 && WIFSTOPPED (status
))
1595 /* Put the signal number in ARGS so that inf_ptrace_detach will
1596 pass it along with PTRACE_DETACH. */
1598 xsnprintf (tem
, 8, "%d", (int) WSTOPSIG (status
));
1600 if (debug_linux_nat
)
1601 fprintf_unfiltered (gdb_stdlog
,
1602 "LND: Sending signal %s to %s\n",
1604 target_pid_to_str (main_lwp
->ptid
));
1607 if (linux_nat_prepare_to_resume
!= NULL
)
1608 linux_nat_prepare_to_resume (main_lwp
);
1609 delete_lwp (main_lwp
->ptid
);
1611 if (forks_exist_p ())
1613 /* Multi-fork case. The current inferior_ptid is being detached
1614 from, but there are other viable forks to debug. Detach from
1615 the current fork, and context-switch to the first
1617 linux_fork_detach (args
, from_tty
);
1620 linux_ops
->to_detach (ops
, args
, from_tty
);
1626 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1630 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
1632 if (inf
->vfork_child
!= NULL
)
1634 if (debug_linux_nat
)
1635 fprintf_unfiltered (gdb_stdlog
,
1636 "RC: Not resuming %s (vfork parent)\n",
1637 target_pid_to_str (lp
->ptid
));
1639 else if (lp
->status
== 0
1640 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
1642 if (debug_linux_nat
)
1643 fprintf_unfiltered (gdb_stdlog
,
1644 "RC: Resuming sibling %s, %s, %s\n",
1645 target_pid_to_str (lp
->ptid
),
1646 (signo
!= GDB_SIGNAL_0
1647 ? strsignal (gdb_signal_to_host (signo
))
1649 step
? "step" : "resume");
1651 if (linux_nat_prepare_to_resume
!= NULL
)
1652 linux_nat_prepare_to_resume (lp
);
1653 linux_ops
->to_resume (linux_ops
,
1654 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
1658 lp
->stopped_by_watchpoint
= 0;
1662 if (debug_linux_nat
)
1663 fprintf_unfiltered (gdb_stdlog
,
1664 "RC: Not resuming sibling %s (has pending)\n",
1665 target_pid_to_str (lp
->ptid
));
1670 if (debug_linux_nat
)
1671 fprintf_unfiltered (gdb_stdlog
,
1672 "RC: Not resuming sibling %s (not stopped)\n",
1673 target_pid_to_str (lp
->ptid
));
1677 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1678 Resume LWP with the last stop signal, if it is in pass state. */
1681 linux_nat_resume_callback (struct lwp_info
*lp
, void *except
)
1683 enum gdb_signal signo
= GDB_SIGNAL_0
;
1690 struct thread_info
*thread
;
1692 thread
= find_thread_ptid (lp
->ptid
);
1695 signo
= thread
->suspend
.stop_signal
;
1696 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1700 resume_lwp (lp
, 0, signo
);
1705 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1708 lp
->last_resume_kind
= resume_stop
;
1713 resume_set_callback (struct lwp_info
*lp
, void *data
)
1716 lp
->last_resume_kind
= resume_continue
;
1721 linux_nat_resume (struct target_ops
*ops
,
1722 ptid_t ptid
, int step
, enum gdb_signal signo
)
1724 struct lwp_info
*lp
;
1727 if (debug_linux_nat
)
1728 fprintf_unfiltered (gdb_stdlog
,
1729 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1730 step
? "step" : "resume",
1731 target_pid_to_str (ptid
),
1732 (signo
!= GDB_SIGNAL_0
1733 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1734 target_pid_to_str (inferior_ptid
));
1736 /* A specific PTID means `step only this process id'. */
1737 resume_many
= (ptid_equal (minus_one_ptid
, ptid
)
1738 || ptid_is_pid (ptid
));
1740 /* Mark the lwps we're resuming as resumed. */
1741 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1743 /* See if it's the current inferior that should be handled
1746 lp
= find_lwp_pid (inferior_ptid
);
1748 lp
= find_lwp_pid (ptid
);
1749 gdb_assert (lp
!= NULL
);
1751 /* Remember if we're stepping. */
1753 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1755 /* If we have a pending wait status for this thread, there is no
1756 point in resuming the process. But first make sure that
1757 linux_nat_wait won't preemptively handle the event - we
1758 should never take this short-circuit if we are going to
1759 leave LP running, since we have skipped resuming all the
1760 other threads. This bit of code needs to be synchronized
1761 with linux_nat_wait. */
1763 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1766 && WSTOPSIG (lp
->status
)
1767 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1769 if (debug_linux_nat
)
1770 fprintf_unfiltered (gdb_stdlog
,
1771 "LLR: Not short circuiting for ignored "
1772 "status 0x%x\n", lp
->status
);
1774 /* FIXME: What should we do if we are supposed to continue
1775 this thread with a signal? */
1776 gdb_assert (signo
== GDB_SIGNAL_0
);
1777 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1782 if (lp
->status
|| lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1784 /* FIXME: What should we do if we are supposed to continue
1785 this thread with a signal? */
1786 gdb_assert (signo
== GDB_SIGNAL_0
);
1788 if (debug_linux_nat
)
1789 fprintf_unfiltered (gdb_stdlog
,
1790 "LLR: Short circuiting for status 0x%x\n",
1793 if (target_can_async_p ())
1795 target_async (inferior_event_handler
, 0);
1796 /* Tell the event loop we have something to process. */
1803 iterate_over_lwps (ptid
, linux_nat_resume_callback
, lp
);
1805 /* Convert to something the lower layer understands. */
1806 ptid
= pid_to_ptid (ptid_get_lwp (lp
->ptid
));
1808 if (linux_nat_prepare_to_resume
!= NULL
)
1809 linux_nat_prepare_to_resume (lp
);
1810 linux_ops
->to_resume (linux_ops
, ptid
, step
, signo
);
1811 lp
->stopped_by_watchpoint
= 0;
1814 if (debug_linux_nat
)
1815 fprintf_unfiltered (gdb_stdlog
,
1816 "LLR: %s %s, %s (resume event thread)\n",
1817 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1818 target_pid_to_str (ptid
),
1819 (signo
!= GDB_SIGNAL_0
1820 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1822 if (target_can_async_p ())
1823 target_async (inferior_event_handler
, 0);
1826 /* Send a signal to an LWP. */
1829 kill_lwp (int lwpid
, int signo
)
1831 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1832 fails, then we are not using nptl threads and we should be using kill. */
1834 #ifdef HAVE_TKILL_SYSCALL
1836 static int tkill_failed
;
1843 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1844 if (errno
!= ENOSYS
)
1851 return kill (lwpid
, signo
);
1854 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1855 event, check if the core is interested in it: if not, ignore the
1856 event, and keep waiting; otherwise, we need to toggle the LWP's
1857 syscall entry/exit status, since the ptrace event itself doesn't
1858 indicate it, and report the trap to higher layers. */
1861 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1863 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1864 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1865 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, lp
->ptid
);
1869 /* If we're stopping threads, there's a SIGSTOP pending, which
1870 makes it so that the LWP reports an immediate syscall return,
1871 followed by the SIGSTOP. Skip seeing that "return" using
1872 PTRACE_CONT directly, and let stop_wait_callback collect the
1873 SIGSTOP. Later when the thread is resumed, a new syscall
1874 entry event. If we didn't do this (and returned 0), we'd
1875 leave a syscall entry pending, and our caller, by using
1876 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1877 itself. Later, when the user re-resumes this LWP, we'd see
1878 another syscall entry event and we'd mistake it for a return.
1880 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1881 (leaving immediately with LWP->signalled set, without issuing
1882 a PTRACE_CONT), it would still be problematic to leave this
1883 syscall enter pending, as later when the thread is resumed,
1884 it would then see the same syscall exit mentioned above,
1885 followed by the delayed SIGSTOP, while the syscall didn't
1886 actually get to execute. It seems it would be even more
1887 confusing to the user. */
1889 if (debug_linux_nat
)
1890 fprintf_unfiltered (gdb_stdlog
,
1891 "LHST: ignoring syscall %d "
1892 "for LWP %ld (stopping threads), "
1893 "resuming with PTRACE_CONT for SIGSTOP\n",
1895 ptid_get_lwp (lp
->ptid
));
1897 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1898 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
1903 if (catch_syscall_enabled ())
1905 /* Always update the entry/return state, even if this particular
1906 syscall isn't interesting to the core now. In async mode,
1907 the user could install a new catchpoint for this syscall
1908 between syscall enter/return, and we'll need to know to
1909 report a syscall return if that happens. */
1910 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1911 ? TARGET_WAITKIND_SYSCALL_RETURN
1912 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1914 if (catching_syscall_number (syscall_number
))
1916 /* Alright, an event to report. */
1917 ourstatus
->kind
= lp
->syscall_state
;
1918 ourstatus
->value
.syscall_number
= syscall_number
;
1920 if (debug_linux_nat
)
1921 fprintf_unfiltered (gdb_stdlog
,
1922 "LHST: stopping for %s of syscall %d"
1925 == TARGET_WAITKIND_SYSCALL_ENTRY
1926 ? "entry" : "return",
1928 ptid_get_lwp (lp
->ptid
));
1932 if (debug_linux_nat
)
1933 fprintf_unfiltered (gdb_stdlog
,
1934 "LHST: ignoring %s of syscall %d "
1936 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1937 ? "entry" : "return",
1939 ptid_get_lwp (lp
->ptid
));
1943 /* If we had been syscall tracing, and hence used PT_SYSCALL
1944 before on this LWP, it could happen that the user removes all
1945 syscall catchpoints before we get to process this event.
1946 There are two noteworthy issues here:
1948 - When stopped at a syscall entry event, resuming with
1949 PT_STEP still resumes executing the syscall and reports a
1952 - Only PT_SYSCALL catches syscall enters. If we last
1953 single-stepped this thread, then this event can't be a
1954 syscall enter. If we last single-stepped this thread, this
1955 has to be a syscall exit.
1957 The points above mean that the next resume, be it PT_STEP or
1958 PT_CONTINUE, can not trigger a syscall trace event. */
1959 if (debug_linux_nat
)
1960 fprintf_unfiltered (gdb_stdlog
,
1961 "LHST: caught syscall event "
1962 "with no syscall catchpoints."
1963 " %d for LWP %ld, ignoring\n",
1965 ptid_get_lwp (lp
->ptid
));
1966 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1969 /* The core isn't interested in this event. For efficiency, avoid
1970 stopping all threads only to have the core resume them all again.
1971 Since we're not stopping threads, if we're still syscall tracing
1972 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1973 subsequent syscall. Simply resume using the inf-ptrace layer,
1974 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1976 /* Note that gdbarch_get_syscall_number may access registers, hence
1978 registers_changed ();
1979 if (linux_nat_prepare_to_resume
!= NULL
)
1980 linux_nat_prepare_to_resume (lp
);
1981 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
1982 lp
->step
, GDB_SIGNAL_0
);
1987 /* Handle a GNU/Linux extended wait response. If we see a clone
1988 event, we need to add the new LWP to our list (and not report the
1989 trap to higher layers). This function returns non-zero if the
1990 event should be ignored and we should wait again. If STOPPING is
1991 true, the new LWP remains stopped, otherwise it is continued. */
1994 linux_handle_extended_wait (struct lwp_info
*lp
, int status
,
1997 int pid
= ptid_get_lwp (lp
->ptid
);
1998 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1999 int event
= status
>> 16;
2001 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
2002 || event
== PTRACE_EVENT_CLONE
)
2004 unsigned long new_pid
;
2007 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
2009 /* If we haven't already seen the new PID stop, wait for it now. */
2010 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
2012 /* The new child has a pending SIGSTOP. We can't affect it until it
2013 hits the SIGSTOP, but we're already attached. */
2014 ret
= my_waitpid (new_pid
, &status
,
2015 (event
== PTRACE_EVENT_CLONE
) ? __WCLONE
: 0);
2017 perror_with_name (_("waiting for new child"));
2018 else if (ret
!= new_pid
)
2019 internal_error (__FILE__
, __LINE__
,
2020 _("wait returned unexpected PID %d"), ret
);
2021 else if (!WIFSTOPPED (status
))
2022 internal_error (__FILE__
, __LINE__
,
2023 _("wait returned unexpected status 0x%x"), status
);
2026 ourstatus
->value
.related_pid
= ptid_build (new_pid
, new_pid
, 0);
2028 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
2030 /* The arch-specific native code may need to know about new
2031 forks even if those end up never mapped to an
2033 if (linux_nat_new_fork
!= NULL
)
2034 linux_nat_new_fork (lp
, new_pid
);
2037 if (event
== PTRACE_EVENT_FORK
2038 && linux_fork_checkpointing_p (ptid_get_pid (lp
->ptid
)))
2040 /* Handle checkpointing by linux-fork.c here as a special
2041 case. We don't want the follow-fork-mode or 'catch fork'
2042 to interfere with this. */
2044 /* This won't actually modify the breakpoint list, but will
2045 physically remove the breakpoints from the child. */
2046 detach_breakpoints (ptid_build (new_pid
, new_pid
, 0));
2048 /* Retain child fork in ptrace (stopped) state. */
2049 if (!find_fork_pid (new_pid
))
2052 /* Report as spurious, so that infrun doesn't want to follow
2053 this fork. We're actually doing an infcall in
2055 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
2057 /* Report the stop to the core. */
2061 if (event
== PTRACE_EVENT_FORK
)
2062 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2063 else if (event
== PTRACE_EVENT_VFORK
)
2064 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2067 struct lwp_info
*new_lp
;
2069 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2071 if (debug_linux_nat
)
2072 fprintf_unfiltered (gdb_stdlog
,
2073 "LHEW: Got clone event "
2074 "from LWP %d, new child is LWP %ld\n",
2077 new_lp
= add_lwp (ptid_build (ptid_get_pid (lp
->ptid
), new_pid
, 0));
2079 new_lp
->stopped
= 1;
2081 if (WSTOPSIG (status
) != SIGSTOP
)
2083 /* This can happen if someone starts sending signals to
2084 the new thread before it gets a chance to run, which
2085 have a lower number than SIGSTOP (e.g. SIGUSR1).
2086 This is an unlikely case, and harder to handle for
2087 fork / vfork than for clone, so we do not try - but
2088 we handle it for clone events here. We'll send
2089 the other signal on to the thread below. */
2091 new_lp
->signalled
= 1;
2095 struct thread_info
*tp
;
2097 /* When we stop for an event in some other thread, and
2098 pull the thread list just as this thread has cloned,
2099 we'll have seen the new thread in the thread_db list
2100 before handling the CLONE event (glibc's
2101 pthread_create adds the new thread to the thread list
2102 before clone'ing, and has the kernel fill in the
2103 thread's tid on the clone call with
2104 CLONE_PARENT_SETTID). If that happened, and the core
2105 had requested the new thread to stop, we'll have
2106 killed it with SIGSTOP. But since SIGSTOP is not an
2107 RT signal, it can only be queued once. We need to be
2108 careful to not resume the LWP if we wanted it to
2109 stop. In that case, we'll leave the SIGSTOP pending.
2110 It will later be reported as GDB_SIGNAL_0. */
2111 tp
= find_thread_ptid (new_lp
->ptid
);
2112 if (tp
!= NULL
&& tp
->stop_requested
)
2113 new_lp
->last_resume_kind
= resume_stop
;
2120 /* Add the new thread to GDB's lists as soon as possible
2123 1) the frontend doesn't have to wait for a stop to
2126 2) we tag it with the correct running state. */
2128 /* If the thread_db layer is active, let it know about
2129 this new thread, and add it to GDB's list. */
2130 if (!thread_db_attach_lwp (new_lp
->ptid
))
2132 /* We're not using thread_db. Add it to GDB's
2134 target_post_attach (ptid_get_lwp (new_lp
->ptid
));
2135 add_thread (new_lp
->ptid
);
2140 set_running (new_lp
->ptid
, 1);
2141 set_executing (new_lp
->ptid
, 1);
2142 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2144 new_lp
->last_resume_kind
= resume_continue
;
2150 /* We created NEW_LP so it cannot yet contain STATUS. */
2151 gdb_assert (new_lp
->status
== 0);
2153 /* Save the wait status to report later. */
2154 if (debug_linux_nat
)
2155 fprintf_unfiltered (gdb_stdlog
,
2156 "LHEW: waitpid of new LWP %ld, "
2157 "saving status %s\n",
2158 (long) ptid_get_lwp (new_lp
->ptid
),
2159 status_to_str (status
));
2160 new_lp
->status
= status
;
2163 /* Note the need to use the low target ops to resume, to
2164 handle resuming with PT_SYSCALL if we have syscall
2168 new_lp
->resumed
= 1;
2172 gdb_assert (new_lp
->last_resume_kind
== resume_continue
);
2173 if (debug_linux_nat
)
2174 fprintf_unfiltered (gdb_stdlog
,
2175 "LHEW: resuming new LWP %ld\n",
2176 ptid_get_lwp (new_lp
->ptid
));
2177 if (linux_nat_prepare_to_resume
!= NULL
)
2178 linux_nat_prepare_to_resume (new_lp
);
2179 linux_ops
->to_resume (linux_ops
, pid_to_ptid (new_pid
),
2181 new_lp
->stopped
= 0;
2185 if (debug_linux_nat
)
2186 fprintf_unfiltered (gdb_stdlog
,
2187 "LHEW: resuming parent LWP %d\n", pid
);
2188 if (linux_nat_prepare_to_resume
!= NULL
)
2189 linux_nat_prepare_to_resume (lp
);
2190 linux_ops
->to_resume (linux_ops
,
2191 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
2200 if (event
== PTRACE_EVENT_EXEC
)
2202 if (debug_linux_nat
)
2203 fprintf_unfiltered (gdb_stdlog
,
2204 "LHEW: Got exec event from LWP %ld\n",
2205 ptid_get_lwp (lp
->ptid
));
2207 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2208 ourstatus
->value
.execd_pathname
2209 = xstrdup (linux_child_pid_to_exec_file (NULL
, pid
));
2214 if (event
== PTRACE_EVENT_VFORK_DONE
)
2216 if (current_inferior ()->waiting_for_vfork_done
)
2218 if (debug_linux_nat
)
2219 fprintf_unfiltered (gdb_stdlog
,
2220 "LHEW: Got expected PTRACE_EVENT_"
2221 "VFORK_DONE from LWP %ld: stopping\n",
2222 ptid_get_lwp (lp
->ptid
));
2224 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2228 if (debug_linux_nat
)
2229 fprintf_unfiltered (gdb_stdlog
,
2230 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2231 "from LWP %ld: resuming\n",
2232 ptid_get_lwp (lp
->ptid
));
2233 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2237 internal_error (__FILE__
, __LINE__
,
2238 _("unknown ptrace event %d"), event
);
2241 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2245 wait_lwp (struct lwp_info
*lp
)
2249 int thread_dead
= 0;
2252 gdb_assert (!lp
->stopped
);
2253 gdb_assert (lp
->status
== 0);
2255 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2256 block_child_signals (&prev_mask
);
2260 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2261 was right and we should just call sigsuspend. */
2263 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, WNOHANG
);
2264 if (pid
== -1 && errno
== ECHILD
)
2265 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, __WCLONE
| WNOHANG
);
2266 if (pid
== -1 && errno
== ECHILD
)
2268 /* The thread has previously exited. We need to delete it
2269 now because, for some vendor 2.4 kernels with NPTL
2270 support backported, there won't be an exit event unless
2271 it is the main thread. 2.6 kernels will report an exit
2272 event for each thread that exits, as expected. */
2274 if (debug_linux_nat
)
2275 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2276 target_pid_to_str (lp
->ptid
));
2281 /* Bugs 10970, 12702.
2282 Thread group leader may have exited in which case we'll lock up in
2283 waitpid if there are other threads, even if they are all zombies too.
2284 Basically, we're not supposed to use waitpid this way.
2285 __WCLONE is not applicable for the leader so we can't use that.
2286 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2287 process; it gets ESRCH both for the zombie and for running processes.
2289 As a workaround, check if we're waiting for the thread group leader and
2290 if it's a zombie, and avoid calling waitpid if it is.
2292 This is racy, what if the tgl becomes a zombie right after we check?
2293 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2294 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2296 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
)
2297 && linux_proc_pid_is_zombie (ptid_get_lwp (lp
->ptid
)))
2300 if (debug_linux_nat
)
2301 fprintf_unfiltered (gdb_stdlog
,
2302 "WL: Thread group leader %s vanished.\n",
2303 target_pid_to_str (lp
->ptid
));
2307 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2308 get invoked despite our caller had them intentionally blocked by
2309 block_child_signals. This is sensitive only to the loop of
2310 linux_nat_wait_1 and there if we get called my_waitpid gets called
2311 again before it gets to sigsuspend so we can safely let the handlers
2312 get executed here. */
2314 sigsuspend (&suspend_mask
);
2317 restore_child_signals_mask (&prev_mask
);
2321 gdb_assert (pid
== ptid_get_lwp (lp
->ptid
));
2323 if (debug_linux_nat
)
2325 fprintf_unfiltered (gdb_stdlog
,
2326 "WL: waitpid %s received %s\n",
2327 target_pid_to_str (lp
->ptid
),
2328 status_to_str (status
));
2331 /* Check if the thread has exited. */
2332 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2335 if (debug_linux_nat
)
2336 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2337 target_pid_to_str (lp
->ptid
));
2347 gdb_assert (WIFSTOPPED (status
));
2350 /* Handle GNU/Linux's syscall SIGTRAPs. */
2351 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2353 /* No longer need the sysgood bit. The ptrace event ends up
2354 recorded in lp->waitstatus if we care for it. We can carry
2355 on handling the event like a regular SIGTRAP from here
2357 status
= W_STOPCODE (SIGTRAP
);
2358 if (linux_handle_syscall_trap (lp
, 1))
2359 return wait_lwp (lp
);
2362 /* Handle GNU/Linux's extended waitstatus for trace events. */
2363 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2365 if (debug_linux_nat
)
2366 fprintf_unfiltered (gdb_stdlog
,
2367 "WL: Handling extended status 0x%06x\n",
2369 if (linux_handle_extended_wait (lp
, status
, 1))
2370 return wait_lwp (lp
);
2376 /* Send a SIGSTOP to LP. */
2379 stop_callback (struct lwp_info
*lp
, void *data
)
2381 if (!lp
->stopped
&& !lp
->signalled
)
2385 if (debug_linux_nat
)
2387 fprintf_unfiltered (gdb_stdlog
,
2388 "SC: kill %s **<SIGSTOP>**\n",
2389 target_pid_to_str (lp
->ptid
));
2392 ret
= kill_lwp (ptid_get_lwp (lp
->ptid
), SIGSTOP
);
2393 if (debug_linux_nat
)
2395 fprintf_unfiltered (gdb_stdlog
,
2396 "SC: lwp kill %d %s\n",
2398 errno
? safe_strerror (errno
) : "ERRNO-OK");
2402 gdb_assert (lp
->status
== 0);
2408 /* Request a stop on LWP. */
2411 linux_stop_lwp (struct lwp_info
*lwp
)
2413 stop_callback (lwp
, NULL
);
2416 /* Return non-zero if LWP PID has a pending SIGINT. */
2419 linux_nat_has_pending_sigint (int pid
)
2421 sigset_t pending
, blocked
, ignored
;
2423 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2425 if (sigismember (&pending
, SIGINT
)
2426 && !sigismember (&ignored
, SIGINT
))
2432 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2435 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2437 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2438 flag to consume the next one. */
2439 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2440 && WSTOPSIG (lp
->status
) == SIGINT
)
2443 lp
->ignore_sigint
= 1;
2448 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2449 This function is called after we know the LWP has stopped; if the LWP
2450 stopped before the expected SIGINT was delivered, then it will never have
2451 arrived. Also, if the signal was delivered to a shared queue and consumed
2452 by a different thread, it will never be delivered to this LWP. */
2455 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2457 if (!lp
->ignore_sigint
)
2460 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp
->ptid
)))
2462 if (debug_linux_nat
)
2463 fprintf_unfiltered (gdb_stdlog
,
2464 "MCIS: Clearing bogus flag for %s\n",
2465 target_pid_to_str (lp
->ptid
));
2466 lp
->ignore_sigint
= 0;
2470 /* Fetch the possible triggered data watchpoint info and store it in
2473 On some archs, like x86, that use debug registers to set
2474 watchpoints, it's possible that the way to know which watched
2475 address trapped, is to check the register that is used to select
2476 which address to watch. Problem is, between setting the watchpoint
2477 and reading back which data address trapped, the user may change
2478 the set of watchpoints, and, as a consequence, GDB changes the
2479 debug registers in the inferior. To avoid reading back a stale
2480 stopped-data-address when that happens, we cache in LP the fact
2481 that a watchpoint trapped, and the corresponding data address, as
2482 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2483 registers meanwhile, we have the cached data we can rely on. */
2486 save_sigtrap (struct lwp_info
*lp
)
2488 struct cleanup
*old_chain
;
2490 if (linux_ops
->to_stopped_by_watchpoint
== NULL
)
2492 lp
->stopped_by_watchpoint
= 0;
2496 old_chain
= save_inferior_ptid ();
2497 inferior_ptid
= lp
->ptid
;
2499 lp
->stopped_by_watchpoint
= linux_ops
->to_stopped_by_watchpoint (linux_ops
);
2501 if (lp
->stopped_by_watchpoint
)
2503 if (linux_ops
->to_stopped_data_address
!= NULL
)
2504 lp
->stopped_data_address_p
=
2505 linux_ops
->to_stopped_data_address (¤t_target
,
2506 &lp
->stopped_data_address
);
2508 lp
->stopped_data_address_p
= 0;
2511 do_cleanups (old_chain
);
2514 /* See save_sigtrap. */
2517 linux_nat_stopped_by_watchpoint (struct target_ops
*ops
)
2519 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2521 gdb_assert (lp
!= NULL
);
2523 return lp
->stopped_by_watchpoint
;
2527 linux_nat_stopped_data_address (struct target_ops
*ops
, CORE_ADDR
*addr_p
)
2529 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2531 gdb_assert (lp
!= NULL
);
2533 *addr_p
= lp
->stopped_data_address
;
2535 return lp
->stopped_data_address_p
;
2538 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2541 sigtrap_is_event (int status
)
2543 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2546 /* SIGTRAP-like events recognizer. */
2548 static int (*linux_nat_status_is_event
) (int status
) = sigtrap_is_event
;
2550 /* Check for SIGTRAP-like events in LP. */
2553 linux_nat_lp_status_is_event (struct lwp_info
*lp
)
2555 /* We check for lp->waitstatus in addition to lp->status, because we can
2556 have pending process exits recorded in lp->status
2557 and W_EXITCODE(0,0) == 0. We should probably have an additional
2558 lp->status_p flag. */
2560 return (lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
2561 && linux_nat_status_is_event (lp
->status
));
2564 /* Set alternative SIGTRAP-like events recognizer. If
2565 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2569 linux_nat_set_status_is_event (struct target_ops
*t
,
2570 int (*status_is_event
) (int status
))
2572 linux_nat_status_is_event
= status_is_event
;
2575 /* Wait until LP is stopped. */
2578 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2580 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2582 /* If this is a vfork parent, bail out, it is not going to report
2583 any SIGSTOP until the vfork is done with. */
2584 if (inf
->vfork_child
!= NULL
)
2591 status
= wait_lwp (lp
);
2595 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2596 && WSTOPSIG (status
) == SIGINT
)
2598 lp
->ignore_sigint
= 0;
2601 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2603 if (debug_linux_nat
)
2604 fprintf_unfiltered (gdb_stdlog
,
2605 "PTRACE_CONT %s, 0, 0 (%s) "
2606 "(discarding SIGINT)\n",
2607 target_pid_to_str (lp
->ptid
),
2608 errno
? safe_strerror (errno
) : "OK");
2610 return stop_wait_callback (lp
, NULL
);
2613 maybe_clear_ignore_sigint (lp
);
2615 if (WSTOPSIG (status
) != SIGSTOP
)
2617 /* The thread was stopped with a signal other than SIGSTOP. */
2621 if (debug_linux_nat
)
2622 fprintf_unfiltered (gdb_stdlog
,
2623 "SWC: Pending event %s in %s\n",
2624 status_to_str ((int) status
),
2625 target_pid_to_str (lp
->ptid
));
2627 /* Save the sigtrap event. */
2628 lp
->status
= status
;
2629 gdb_assert (lp
->signalled
);
2633 /* We caught the SIGSTOP that we intended to catch, so
2634 there's no SIGSTOP pending. */
2636 if (debug_linux_nat
)
2637 fprintf_unfiltered (gdb_stdlog
,
2638 "SWC: Delayed SIGSTOP caught for %s.\n",
2639 target_pid_to_str (lp
->ptid
));
2641 /* Reset SIGNALLED only after the stop_wait_callback call
2642 above as it does gdb_assert on SIGNALLED. */
2650 /* Return non-zero if LP has a wait status pending. */
2653 status_callback (struct lwp_info
*lp
, void *data
)
2655 /* Only report a pending wait status if we pretend that this has
2656 indeed been resumed. */
2660 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2662 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2663 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2664 0', so a clean process exit can not be stored pending in
2665 lp->status, it is indistinguishable from
2666 no-pending-status. */
2670 if (lp
->status
!= 0)
2676 /* Return non-zero if LP isn't stopped. */
2679 running_callback (struct lwp_info
*lp
, void *data
)
2681 return (!lp
->stopped
2682 || ((lp
->status
!= 0
2683 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2687 /* Count the LWP's that have had events. */
2690 count_events_callback (struct lwp_info
*lp
, void *data
)
2694 gdb_assert (count
!= NULL
);
2696 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2697 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2703 /* Select the LWP (if any) that is currently being single-stepped. */
2706 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2708 if (lp
->last_resume_kind
== resume_step
2715 /* Select the Nth LWP that has had a SIGTRAP event. */
2718 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2720 int *selector
= data
;
2722 gdb_assert (selector
!= NULL
);
2724 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2725 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2726 if ((*selector
)-- == 0)
2733 cancel_breakpoint (struct lwp_info
*lp
)
2735 /* Arrange for a breakpoint to be hit again later. We don't keep
2736 the SIGTRAP status and don't forward the SIGTRAP signal to the
2737 LWP. We will handle the current event, eventually we will resume
2738 this LWP, and this breakpoint will trap again.
2740 If we do not do this, then we run the risk that the user will
2741 delete or disable the breakpoint, but the LWP will have already
2744 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2745 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2748 pc
= regcache_read_pc (regcache
) - target_decr_pc_after_break (gdbarch
);
2749 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2751 if (debug_linux_nat
)
2752 fprintf_unfiltered (gdb_stdlog
,
2753 "CB: Push back breakpoint for %s\n",
2754 target_pid_to_str (lp
->ptid
));
2756 /* Back up the PC if necessary. */
2757 if (target_decr_pc_after_break (gdbarch
))
2758 regcache_write_pc (regcache
, pc
);
2766 cancel_breakpoints_callback (struct lwp_info
*lp
, void *data
)
2768 struct lwp_info
*event_lp
= data
;
2770 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2774 /* If a LWP other than the LWP that we're reporting an event for has
2775 hit a GDB breakpoint (as opposed to some random trap signal),
2776 then just arrange for it to hit it again later. We don't keep
2777 the SIGTRAP status and don't forward the SIGTRAP signal to the
2778 LWP. We will handle the current event, eventually we will resume
2779 all LWPs, and this one will get its breakpoint trap again.
2781 If we do not do this, then we run the risk that the user will
2782 delete or disable the breakpoint, but the LWP will have already
2785 if (linux_nat_lp_status_is_event (lp
)
2786 && cancel_breakpoint (lp
))
2787 /* Throw away the SIGTRAP. */
2793 /* Select one LWP out of those that have events pending. */
2796 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2799 int random_selector
;
2800 struct lwp_info
*event_lp
;
2802 /* Record the wait status for the original LWP. */
2803 (*orig_lp
)->status
= *status
;
2805 /* Give preference to any LWP that is being single-stepped. */
2806 event_lp
= iterate_over_lwps (filter
,
2807 select_singlestep_lwp_callback
, NULL
);
2808 if (event_lp
!= NULL
)
2810 if (debug_linux_nat
)
2811 fprintf_unfiltered (gdb_stdlog
,
2812 "SEL: Select single-step %s\n",
2813 target_pid_to_str (event_lp
->ptid
));
2817 /* No single-stepping LWP. Select one at random, out of those
2818 which have had SIGTRAP events. */
2820 /* First see how many SIGTRAP events we have. */
2821 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2823 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2824 random_selector
= (int)
2825 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2827 if (debug_linux_nat
&& num_events
> 1)
2828 fprintf_unfiltered (gdb_stdlog
,
2829 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2830 num_events
, random_selector
);
2832 event_lp
= iterate_over_lwps (filter
,
2833 select_event_lwp_callback
,
2837 if (event_lp
!= NULL
)
2839 /* Switch the event LWP. */
2840 *orig_lp
= event_lp
;
2841 *status
= event_lp
->status
;
2844 /* Flush the wait status for the event LWP. */
2845 (*orig_lp
)->status
= 0;
2848 /* Return non-zero if LP has been resumed. */
2851 resumed_callback (struct lwp_info
*lp
, void *data
)
2856 /* Stop an active thread, verify it still exists, then resume it. If
2857 the thread ends up with a pending status, then it is not resumed,
2858 and *DATA (really a pointer to int), is set. */
2861 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2863 int *new_pending_p
= data
;
2867 ptid_t ptid
= lp
->ptid
;
2869 stop_callback (lp
, NULL
);
2870 stop_wait_callback (lp
, NULL
);
2872 /* Resume if the lwp still exists, and the core wanted it
2874 lp
= find_lwp_pid (ptid
);
2877 if (lp
->last_resume_kind
== resume_stop
2880 /* The core wanted the LWP to stop. Even if it stopped
2881 cleanly (with SIGSTOP), leave the event pending. */
2882 if (debug_linux_nat
)
2883 fprintf_unfiltered (gdb_stdlog
,
2884 "SARC: core wanted LWP %ld stopped "
2885 "(leaving SIGSTOP pending)\n",
2886 ptid_get_lwp (lp
->ptid
));
2887 lp
->status
= W_STOPCODE (SIGSTOP
);
2890 if (lp
->status
== 0)
2892 if (debug_linux_nat
)
2893 fprintf_unfiltered (gdb_stdlog
,
2894 "SARC: re-resuming LWP %ld\n",
2895 ptid_get_lwp (lp
->ptid
));
2896 resume_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2900 if (debug_linux_nat
)
2901 fprintf_unfiltered (gdb_stdlog
,
2902 "SARC: not re-resuming LWP %ld "
2904 ptid_get_lwp (lp
->ptid
));
2913 /* Check if we should go on and pass this event to common code.
2914 Return the affected lwp if we are, or NULL otherwise. If we stop
2915 all lwps temporarily, we may end up with new pending events in some
2916 other lwp. In that case set *NEW_PENDING_P to true. */
2918 static struct lwp_info
*
2919 linux_nat_filter_event (int lwpid
, int status
, int *new_pending_p
)
2921 struct lwp_info
*lp
;
2925 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2927 /* Check for stop events reported by a process we didn't already
2928 know about - anything not already in our LWP list.
2930 If we're expecting to receive stopped processes after
2931 fork, vfork, and clone events, then we'll just add the
2932 new one to our list and go back to waiting for the event
2933 to be reported - the stopped process might be returned
2934 from waitpid before or after the event is.
2936 But note the case of a non-leader thread exec'ing after the
2937 leader having exited, and gone from our lists. The non-leader
2938 thread changes its tid to the tgid. */
2940 if (WIFSTOPPED (status
) && lp
== NULL
2941 && (WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 == PTRACE_EVENT_EXEC
))
2943 /* A multi-thread exec after we had seen the leader exiting. */
2944 if (debug_linux_nat
)
2945 fprintf_unfiltered (gdb_stdlog
,
2946 "LLW: Re-adding thread group leader LWP %d.\n",
2949 lp
= add_lwp (ptid_build (lwpid
, lwpid
, 0));
2952 add_thread (lp
->ptid
);
2955 if (WIFSTOPPED (status
) && !lp
)
2957 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2961 /* Make sure we don't report an event for the exit of an LWP not in
2962 our list, i.e. not part of the current process. This can happen
2963 if we detach from a program we originally forked and then it
2965 if (!WIFSTOPPED (status
) && !lp
)
2968 /* This LWP is stopped now. (And if dead, this prevents it from
2969 ever being continued.) */
2972 /* Handle GNU/Linux's syscall SIGTRAPs. */
2973 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2975 /* No longer need the sysgood bit. The ptrace event ends up
2976 recorded in lp->waitstatus if we care for it. We can carry
2977 on handling the event like a regular SIGTRAP from here
2979 status
= W_STOPCODE (SIGTRAP
);
2980 if (linux_handle_syscall_trap (lp
, 0))
2984 /* Handle GNU/Linux's extended waitstatus for trace events. */
2985 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2987 if (debug_linux_nat
)
2988 fprintf_unfiltered (gdb_stdlog
,
2989 "LLW: Handling extended status 0x%06x\n",
2991 if (linux_handle_extended_wait (lp
, status
, 0))
2995 if (linux_nat_status_is_event (status
))
2998 /* Check if the thread has exited. */
2999 if ((WIFEXITED (status
) || WIFSIGNALED (status
))
3000 && num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
3002 /* If this is the main thread, we must stop all threads and verify
3003 if they are still alive. This is because in the nptl thread model
3004 on Linux 2.4, there is no signal issued for exiting LWPs
3005 other than the main thread. We only get the main thread exit
3006 signal once all child threads have already exited. If we
3007 stop all the threads and use the stop_wait_callback to check
3008 if they have exited we can determine whether this signal
3009 should be ignored or whether it means the end of the debugged
3010 application, regardless of which threading model is being
3012 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
))
3014 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
3015 stop_and_resume_callback
, new_pending_p
);
3018 if (debug_linux_nat
)
3019 fprintf_unfiltered (gdb_stdlog
,
3020 "LLW: %s exited.\n",
3021 target_pid_to_str (lp
->ptid
));
3023 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
3025 /* If there is at least one more LWP, then the exit signal
3026 was not the end of the debugged application and should be
3033 /* Check if the current LWP has previously exited. In the nptl
3034 thread model, LWPs other than the main thread do not issue
3035 signals when they exit so we must check whenever the thread has
3036 stopped. A similar check is made in stop_wait_callback(). */
3037 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1 && !linux_thread_alive (lp
->ptid
))
3039 ptid_t ptid
= pid_to_ptid (ptid_get_pid (lp
->ptid
));
3041 if (debug_linux_nat
)
3042 fprintf_unfiltered (gdb_stdlog
,
3043 "LLW: %s exited.\n",
3044 target_pid_to_str (lp
->ptid
));
3048 /* Make sure there is at least one thread running. */
3049 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
3051 /* Discard the event. */
3055 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3056 an attempt to stop an LWP. */
3058 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3060 if (debug_linux_nat
)
3061 fprintf_unfiltered (gdb_stdlog
,
3062 "LLW: Delayed SIGSTOP caught for %s.\n",
3063 target_pid_to_str (lp
->ptid
));
3067 if (lp
->last_resume_kind
!= resume_stop
)
3069 /* This is a delayed SIGSTOP. */
3071 registers_changed ();
3073 if (linux_nat_prepare_to_resume
!= NULL
)
3074 linux_nat_prepare_to_resume (lp
);
3075 linux_ops
->to_resume (linux_ops
,
3076 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3077 lp
->step
, GDB_SIGNAL_0
);
3078 if (debug_linux_nat
)
3079 fprintf_unfiltered (gdb_stdlog
,
3080 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3082 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3083 target_pid_to_str (lp
->ptid
));
3086 gdb_assert (lp
->resumed
);
3088 /* Discard the event. */
3093 /* Make sure we don't report a SIGINT that we have already displayed
3094 for another thread. */
3095 if (lp
->ignore_sigint
3096 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3098 if (debug_linux_nat
)
3099 fprintf_unfiltered (gdb_stdlog
,
3100 "LLW: Delayed SIGINT caught for %s.\n",
3101 target_pid_to_str (lp
->ptid
));
3103 /* This is a delayed SIGINT. */
3104 lp
->ignore_sigint
= 0;
3106 registers_changed ();
3107 if (linux_nat_prepare_to_resume
!= NULL
)
3108 linux_nat_prepare_to_resume (lp
);
3109 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3110 lp
->step
, GDB_SIGNAL_0
);
3111 if (debug_linux_nat
)
3112 fprintf_unfiltered (gdb_stdlog
,
3113 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3115 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3116 target_pid_to_str (lp
->ptid
));
3119 gdb_assert (lp
->resumed
);
3121 /* Discard the event. */
3125 /* An interesting event. */
3127 lp
->status
= status
;
3131 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3132 their exits until all other threads in the group have exited. */
3135 check_zombie_leaders (void)
3137 struct inferior
*inf
;
3141 struct lwp_info
*leader_lp
;
3146 leader_lp
= find_lwp_pid (pid_to_ptid (inf
->pid
));
3147 if (leader_lp
!= NULL
3148 /* Check if there are other threads in the group, as we may
3149 have raced with the inferior simply exiting. */
3150 && num_lwps (inf
->pid
) > 1
3151 && linux_proc_pid_is_zombie (inf
->pid
))
3153 if (debug_linux_nat
)
3154 fprintf_unfiltered (gdb_stdlog
,
3155 "CZL: Thread group leader %d zombie "
3156 "(it exited, or another thread execd).\n",
3159 /* A leader zombie can mean one of two things:
3161 - It exited, and there's an exit status pending
3162 available, or only the leader exited (not the whole
3163 program). In the latter case, we can't waitpid the
3164 leader's exit status until all other threads are gone.
3166 - There are 3 or more threads in the group, and a thread
3167 other than the leader exec'd. On an exec, the Linux
3168 kernel destroys all other threads (except the execing
3169 one) in the thread group, and resets the execing thread's
3170 tid to the tgid. No exit notification is sent for the
3171 execing thread -- from the ptracer's perspective, it
3172 appears as though the execing thread just vanishes.
3173 Until we reap all other threads except the leader and the
3174 execing thread, the leader will be zombie, and the
3175 execing thread will be in `D (disc sleep)'. As soon as
3176 all other threads are reaped, the execing thread changes
3177 it's tid to the tgid, and the previous (zombie) leader
3178 vanishes, giving place to the "new" leader. We could try
3179 distinguishing the exit and exec cases, by waiting once
3180 more, and seeing if something comes out, but it doesn't
3181 sound useful. The previous leader _does_ go away, and
3182 we'll re-add the new one once we see the exec event
3183 (which is just the same as what would happen if the
3184 previous leader did exit voluntarily before some other
3187 if (debug_linux_nat
)
3188 fprintf_unfiltered (gdb_stdlog
,
3189 "CZL: Thread group leader %d vanished.\n",
3191 exit_lwp (leader_lp
);
3197 linux_nat_wait_1 (struct target_ops
*ops
,
3198 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3201 static sigset_t prev_mask
;
3202 enum resume_kind last_resume_kind
;
3203 struct lwp_info
*lp
;
3206 if (debug_linux_nat
)
3207 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3209 /* The first time we get here after starting a new inferior, we may
3210 not have added it to the LWP list yet - this is the earliest
3211 moment at which we know its PID. */
3212 if (ptid_is_pid (inferior_ptid
))
3214 /* Upgrade the main thread's ptid. */
3215 thread_change_ptid (inferior_ptid
,
3216 ptid_build (ptid_get_pid (inferior_ptid
),
3217 ptid_get_pid (inferior_ptid
), 0));
3219 lp
= add_initial_lwp (inferior_ptid
);
3223 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3224 block_child_signals (&prev_mask
);
3230 /* First check if there is a LWP with a wait status pending. */
3231 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3233 /* Any LWP in the PTID group that's been resumed will do. */
3234 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3237 if (debug_linux_nat
&& lp
->status
)
3238 fprintf_unfiltered (gdb_stdlog
,
3239 "LLW: Using pending wait status %s for %s.\n",
3240 status_to_str (lp
->status
),
3241 target_pid_to_str (lp
->ptid
));
3244 else if (ptid_lwp_p (ptid
))
3246 if (debug_linux_nat
)
3247 fprintf_unfiltered (gdb_stdlog
,
3248 "LLW: Waiting for specific LWP %s.\n",
3249 target_pid_to_str (ptid
));
3251 /* We have a specific LWP to check. */
3252 lp
= find_lwp_pid (ptid
);
3255 if (debug_linux_nat
&& lp
->status
)
3256 fprintf_unfiltered (gdb_stdlog
,
3257 "LLW: Using pending wait status %s for %s.\n",
3258 status_to_str (lp
->status
),
3259 target_pid_to_str (lp
->ptid
));
3261 /* We check for lp->waitstatus in addition to lp->status,
3262 because we can have pending process exits recorded in
3263 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3264 an additional lp->status_p flag. */
3265 if (lp
->status
== 0 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3269 if (!target_can_async_p ())
3271 /* Causes SIGINT to be passed on to the attached process. */
3275 /* But if we don't find a pending event, we'll have to wait. */
3281 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3284 - If the thread group leader exits while other threads in the
3285 thread group still exist, waitpid(TGID, ...) hangs. That
3286 waitpid won't return an exit status until the other threads
3287 in the group are reapped.
3289 - When a non-leader thread execs, that thread just vanishes
3290 without reporting an exit (so we'd hang if we waited for it
3291 explicitly in that case). The exec event is reported to
3295 lwpid
= my_waitpid (-1, &status
, __WCLONE
| WNOHANG
);
3296 if (lwpid
== 0 || (lwpid
== -1 && errno
== ECHILD
))
3297 lwpid
= my_waitpid (-1, &status
, WNOHANG
);
3299 if (debug_linux_nat
)
3300 fprintf_unfiltered (gdb_stdlog
,
3301 "LNW: waitpid(-1, ...) returned %d, %s\n",
3302 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3306 /* If this is true, then we paused LWPs momentarily, and may
3307 now have pending events to handle. */
3310 if (debug_linux_nat
)
3312 fprintf_unfiltered (gdb_stdlog
,
3313 "LLW: waitpid %ld received %s\n",
3314 (long) lwpid
, status_to_str (status
));
3317 lp
= linux_nat_filter_event (lwpid
, status
, &new_pending
);
3319 /* STATUS is now no longer valid, use LP->STATUS instead. */
3322 if (lp
&& !ptid_match (lp
->ptid
, ptid
))
3324 gdb_assert (lp
->resumed
);
3326 if (debug_linux_nat
)
3328 "LWP %ld got an event %06x, leaving pending.\n",
3329 ptid_get_lwp (lp
->ptid
), lp
->status
);
3331 if (WIFSTOPPED (lp
->status
))
3333 if (WSTOPSIG (lp
->status
) != SIGSTOP
)
3335 /* Cancel breakpoint hits. The breakpoint may
3336 be removed before we fetch events from this
3337 process to report to the core. It is best
3338 not to assume the moribund breakpoints
3339 heuristic always handles these cases --- it
3340 could be too many events go through to the
3341 core before this one is handled. All-stop
3342 always cancels breakpoint hits in all
3345 && linux_nat_lp_status_is_event (lp
)
3346 && cancel_breakpoint (lp
))
3348 /* Throw away the SIGTRAP. */
3351 if (debug_linux_nat
)
3353 "LLW: LWP %ld hit a breakpoint while"
3354 " waiting for another process;"
3356 ptid_get_lwp (lp
->ptid
));
3362 else if (WIFEXITED (lp
->status
) || WIFSIGNALED (lp
->status
))
3364 if (debug_linux_nat
)
3366 "Process %ld exited while stopping LWPs\n",
3367 ptid_get_lwp (lp
->ptid
));
3369 /* This was the last lwp in the process. Since
3370 events are serialized to GDB core, and we can't
3371 report this one right now, but GDB core and the
3372 other target layers will want to be notified
3373 about the exit code/signal, leave the status
3374 pending for the next time we're able to report
3377 /* Dead LWP's aren't expected to reported a pending
3381 /* Store the pending event in the waitstatus as
3382 well, because W_EXITCODE(0,0) == 0. */
3383 store_waitstatus (&lp
->waitstatus
, lp
->status
);
3392 /* Some LWP now has a pending event. Go all the way
3393 back to check it. */
3399 /* We got an event to report to the core. */
3403 /* Retry until nothing comes out of waitpid. A single
3404 SIGCHLD can indicate more than one child stopped. */
3408 /* Check for zombie thread group leaders. Those can't be reaped
3409 until all other threads in the thread group are. */
3410 check_zombie_leaders ();
3412 /* If there are no resumed children left, bail. We'd be stuck
3413 forever in the sigsuspend call below otherwise. */
3414 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3416 if (debug_linux_nat
)
3417 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3419 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3421 if (!target_can_async_p ())
3422 clear_sigint_trap ();
3424 restore_child_signals_mask (&prev_mask
);
3425 return minus_one_ptid
;
3428 /* No interesting event to report to the core. */
3430 if (target_options
& TARGET_WNOHANG
)
3432 if (debug_linux_nat
)
3433 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3435 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3436 restore_child_signals_mask (&prev_mask
);
3437 return minus_one_ptid
;
3440 /* We shouldn't end up here unless we want to try again. */
3441 gdb_assert (lp
== NULL
);
3443 /* Block until we get an event reported with SIGCHLD. */
3444 sigsuspend (&suspend_mask
);
3447 if (!target_can_async_p ())
3448 clear_sigint_trap ();
3452 status
= lp
->status
;
3455 /* Don't report signals that GDB isn't interested in, such as
3456 signals that are neither printed nor stopped upon. Stopping all
3457 threads can be a bit time-consuming so if we want decent
3458 performance with heavily multi-threaded programs, especially when
3459 they're using a high frequency timer, we'd better avoid it if we
3462 if (WIFSTOPPED (status
))
3464 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3466 /* When using hardware single-step, we need to report every signal.
3467 Otherwise, signals in pass_mask may be short-circuited. */
3469 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
)))
3471 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3472 here? It is not clear we should. GDB may not expect
3473 other threads to run. On the other hand, not resuming
3474 newly attached threads may cause an unwanted delay in
3475 getting them running. */
3476 registers_changed ();
3477 if (linux_nat_prepare_to_resume
!= NULL
)
3478 linux_nat_prepare_to_resume (lp
);
3479 linux_ops
->to_resume (linux_ops
,
3480 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3482 if (debug_linux_nat
)
3483 fprintf_unfiltered (gdb_stdlog
,
3484 "LLW: %s %s, %s (preempt 'handle')\n",
3486 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3487 target_pid_to_str (lp
->ptid
),
3488 (signo
!= GDB_SIGNAL_0
3489 ? strsignal (gdb_signal_to_host (signo
))
3497 /* Only do the below in all-stop, as we currently use SIGINT
3498 to implement target_stop (see linux_nat_stop) in
3500 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3502 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3503 forwarded to the entire process group, that is, all LWPs
3504 will receive it - unless they're using CLONE_THREAD to
3505 share signals. Since we only want to report it once, we
3506 mark it as ignored for all LWPs except this one. */
3507 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid
)),
3508 set_ignore_sigint
, NULL
);
3509 lp
->ignore_sigint
= 0;
3512 maybe_clear_ignore_sigint (lp
);
3516 /* This LWP is stopped now. */
3519 if (debug_linux_nat
)
3520 fprintf_unfiltered (gdb_stdlog
, "LLW: Candidate event %s in %s.\n",
3521 status_to_str (status
), target_pid_to_str (lp
->ptid
));
3525 /* Now stop all other LWP's ... */
3526 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3528 /* ... and wait until all of them have reported back that
3529 they're no longer running. */
3530 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3532 /* If we're not waiting for a specific LWP, choose an event LWP
3533 from among those that have had events. Giving equal priority
3534 to all LWPs that have had events helps prevent
3536 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3537 select_event_lwp (ptid
, &lp
, &status
);
3539 /* Now that we've selected our final event LWP, cancel any
3540 breakpoints in other LWPs that have hit a GDB breakpoint.
3541 See the comment in cancel_breakpoints_callback to find out
3543 iterate_over_lwps (minus_one_ptid
, cancel_breakpoints_callback
, lp
);
3545 /* We'll need this to determine whether to report a SIGSTOP as
3546 TARGET_WAITKIND_0. Need to take a copy because
3547 resume_clear_callback clears it. */
3548 last_resume_kind
= lp
->last_resume_kind
;
3550 /* In all-stop, from the core's perspective, all LWPs are now
3551 stopped until a new resume action is sent over. */
3552 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3557 last_resume_kind
= lp
->last_resume_kind
;
3558 resume_clear_callback (lp
, NULL
);
3561 if (linux_nat_status_is_event (status
))
3563 if (debug_linux_nat
)
3564 fprintf_unfiltered (gdb_stdlog
,
3565 "LLW: trap ptid is %s.\n",
3566 target_pid_to_str (lp
->ptid
));
3569 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3571 *ourstatus
= lp
->waitstatus
;
3572 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3575 store_waitstatus (ourstatus
, status
);
3577 if (debug_linux_nat
)
3578 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3580 restore_child_signals_mask (&prev_mask
);
3582 if (last_resume_kind
== resume_stop
3583 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3584 && WSTOPSIG (status
) == SIGSTOP
)
3586 /* A thread that has been requested to stop by GDB with
3587 target_stop, and it stopped cleanly, so report as SIG0. The
3588 use of SIGSTOP is an implementation detail. */
3589 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3592 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3593 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3596 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3601 /* Resume LWPs that are currently stopped without any pending status
3602 to report, but are resumed from the core's perspective. */
3605 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3607 ptid_t
*wait_ptid_p
= data
;
3612 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3614 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3615 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3616 CORE_ADDR pc
= regcache_read_pc (regcache
);
3618 gdb_assert (is_executing (lp
->ptid
));
3620 /* Don't bother if there's a breakpoint at PC that we'd hit
3621 immediately, and we're not waiting for this LWP. */
3622 if (!ptid_match (lp
->ptid
, *wait_ptid_p
))
3624 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
3628 if (debug_linux_nat
)
3629 fprintf_unfiltered (gdb_stdlog
,
3630 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3631 target_pid_to_str (lp
->ptid
),
3632 paddress (gdbarch
, pc
),
3635 registers_changed ();
3636 if (linux_nat_prepare_to_resume
!= NULL
)
3637 linux_nat_prepare_to_resume (lp
);
3638 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3639 lp
->step
, GDB_SIGNAL_0
);
3641 lp
->stopped_by_watchpoint
= 0;
3648 linux_nat_wait (struct target_ops
*ops
,
3649 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3654 if (debug_linux_nat
)
3656 char *options_string
;
3658 options_string
= target_options_to_string (target_options
);
3659 fprintf_unfiltered (gdb_stdlog
,
3660 "linux_nat_wait: [%s], [%s]\n",
3661 target_pid_to_str (ptid
),
3663 xfree (options_string
);
3666 /* Flush the async file first. */
3667 if (target_can_async_p ())
3668 async_file_flush ();
3670 /* Resume LWPs that are currently stopped without any pending status
3671 to report, but are resumed from the core's perspective. LWPs get
3672 in this state if we find them stopping at a time we're not
3673 interested in reporting the event (target_wait on a
3674 specific_process, for example, see linux_nat_wait_1), and
3675 meanwhile the event became uninteresting. Don't bother resuming
3676 LWPs we're not going to wait for if they'd stop immediately. */
3678 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3680 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
3682 /* If we requested any event, and something came out, assume there
3683 may be more. If we requested a specific lwp or process, also
3684 assume there may be more. */
3685 if (target_can_async_p ()
3686 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3687 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3688 || !ptid_equal (ptid
, minus_one_ptid
)))
3691 /* Get ready for the next event. */
3692 if (target_can_async_p ())
3693 target_async (inferior_event_handler
, 0);
3699 kill_callback (struct lwp_info
*lp
, void *data
)
3701 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3704 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGKILL
);
3705 if (debug_linux_nat
)
3707 int save_errno
= errno
;
3709 fprintf_unfiltered (gdb_stdlog
,
3710 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3711 target_pid_to_str (lp
->ptid
),
3712 save_errno
? safe_strerror (save_errno
) : "OK");
3715 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3718 ptrace (PTRACE_KILL
, ptid_get_lwp (lp
->ptid
), 0, 0);
3719 if (debug_linux_nat
)
3721 int save_errno
= errno
;
3723 fprintf_unfiltered (gdb_stdlog
,
3724 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3725 target_pid_to_str (lp
->ptid
),
3726 save_errno
? safe_strerror (save_errno
) : "OK");
3733 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3737 /* We must make sure that there are no pending events (delayed
3738 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3739 program doesn't interfere with any following debugging session. */
3741 /* For cloned processes we must check both with __WCLONE and
3742 without, since the exit status of a cloned process isn't reported
3748 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, __WCLONE
);
3749 if (pid
!= (pid_t
) -1)
3751 if (debug_linux_nat
)
3752 fprintf_unfiltered (gdb_stdlog
,
3753 "KWC: wait %s received unknown.\n",
3754 target_pid_to_str (lp
->ptid
));
3755 /* The Linux kernel sometimes fails to kill a thread
3756 completely after PTRACE_KILL; that goes from the stop
3757 point in do_fork out to the one in
3758 get_signal_to_deliever and waits again. So kill it
3760 kill_callback (lp
, NULL
);
3763 while (pid
== ptid_get_lwp (lp
->ptid
));
3765 gdb_assert (pid
== -1 && errno
== ECHILD
);
3770 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, 0);
3771 if (pid
!= (pid_t
) -1)
3773 if (debug_linux_nat
)
3774 fprintf_unfiltered (gdb_stdlog
,
3775 "KWC: wait %s received unk.\n",
3776 target_pid_to_str (lp
->ptid
));
3777 /* See the call to kill_callback above. */
3778 kill_callback (lp
, NULL
);
3781 while (pid
== ptid_get_lwp (lp
->ptid
));
3783 gdb_assert (pid
== -1 && errno
== ECHILD
);
3788 linux_nat_kill (struct target_ops
*ops
)
3790 struct target_waitstatus last
;
3794 /* If we're stopped while forking and we haven't followed yet,
3795 kill the other task. We need to do this first because the
3796 parent will be sleeping if this is a vfork. */
3798 get_last_target_status (&last_ptid
, &last
);
3800 if (last
.kind
== TARGET_WAITKIND_FORKED
3801 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3803 ptrace (PT_KILL
, ptid_get_pid (last
.value
.related_pid
), 0, 0);
3806 /* Let the arch-specific native code know this process is
3808 linux_nat_forget_process (ptid_get_pid (last
.value
.related_pid
));
3811 if (forks_exist_p ())
3812 linux_fork_killall ();
3815 ptid_t ptid
= pid_to_ptid (ptid_get_pid (inferior_ptid
));
3817 /* Stop all threads before killing them, since ptrace requires
3818 that the thread is stopped to sucessfully PTRACE_KILL. */
3819 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3820 /* ... and wait until all of them have reported back that
3821 they're no longer running. */
3822 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3824 /* Kill all LWP's ... */
3825 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3827 /* ... and wait until we've flushed all events. */
3828 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3831 target_mourn_inferior ();
3835 linux_nat_mourn_inferior (struct target_ops
*ops
)
3837 int pid
= ptid_get_pid (inferior_ptid
);
3839 purge_lwp_list (pid
);
3841 if (! forks_exist_p ())
3842 /* Normal case, no other forks available. */
3843 linux_ops
->to_mourn_inferior (ops
);
3845 /* Multi-fork case. The current inferior_ptid has exited, but
3846 there are other viable forks to debug. Delete the exiting
3847 one and context-switch to the first available. */
3848 linux_fork_mourn_inferior ();
3850 /* Let the arch-specific native code know this process is gone. */
3851 linux_nat_forget_process (pid
);
3854 /* Convert a native/host siginfo object, into/from the siginfo in the
3855 layout of the inferiors' architecture. */
3858 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3862 if (linux_nat_siginfo_fixup
!= NULL
)
3863 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3865 /* If there was no callback, or the callback didn't do anything,
3866 then just do a straight memcpy. */
3870 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3872 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3876 static enum target_xfer_status
3877 linux_xfer_siginfo (struct target_ops
*ops
, enum target_object object
,
3878 const char *annex
, gdb_byte
*readbuf
,
3879 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3880 ULONGEST
*xfered_len
)
3884 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3886 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3887 gdb_assert (readbuf
|| writebuf
);
3889 pid
= ptid_get_lwp (inferior_ptid
);
3891 pid
= ptid_get_pid (inferior_ptid
);
3893 if (offset
> sizeof (siginfo
))
3894 return TARGET_XFER_E_IO
;
3897 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3899 return TARGET_XFER_E_IO
;
3901 /* When GDB is built as a 64-bit application, ptrace writes into
3902 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3903 inferior with a 64-bit GDB should look the same as debugging it
3904 with a 32-bit GDB, we need to convert it. GDB core always sees
3905 the converted layout, so any read/write will have to be done
3907 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3909 if (offset
+ len
> sizeof (siginfo
))
3910 len
= sizeof (siginfo
) - offset
;
3912 if (readbuf
!= NULL
)
3913 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3916 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3918 /* Convert back to ptrace layout before flushing it out. */
3919 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3922 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3924 return TARGET_XFER_E_IO
;
3928 return TARGET_XFER_OK
;
3931 static enum target_xfer_status
3932 linux_nat_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3933 const char *annex
, gdb_byte
*readbuf
,
3934 const gdb_byte
*writebuf
,
3935 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3937 struct cleanup
*old_chain
;
3938 enum target_xfer_status xfer
;
3940 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3941 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3942 offset
, len
, xfered_len
);
3944 /* The target is connected but no live inferior is selected. Pass
3945 this request down to a lower stratum (e.g., the executable
3947 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3948 return TARGET_XFER_EOF
;
3950 old_chain
= save_inferior_ptid ();
3952 if (ptid_lwp_p (inferior_ptid
))
3953 inferior_ptid
= pid_to_ptid (ptid_get_lwp (inferior_ptid
));
3955 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3956 offset
, len
, xfered_len
);
3958 do_cleanups (old_chain
);
3963 linux_thread_alive (ptid_t ptid
)
3967 gdb_assert (ptid_lwp_p (ptid
));
3969 /* Send signal 0 instead of anything ptrace, because ptracing a
3970 running thread errors out claiming that the thread doesn't
3972 err
= kill_lwp (ptid_get_lwp (ptid
), 0);
3974 if (debug_linux_nat
)
3975 fprintf_unfiltered (gdb_stdlog
,
3976 "LLTA: KILL(SIG0) %s (%s)\n",
3977 target_pid_to_str (ptid
),
3978 err
? safe_strerror (tmp_errno
) : "OK");
3987 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3989 return linux_thread_alive (ptid
);
3993 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3995 static char buf
[64];
3997 if (ptid_lwp_p (ptid
)
3998 && (ptid_get_pid (ptid
) != ptid_get_lwp (ptid
)
3999 || num_lwps (ptid_get_pid (ptid
)) > 1))
4001 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid_get_lwp (ptid
));
4005 return normal_pid_to_str (ptid
);
4009 linux_nat_thread_name (struct target_ops
*self
, struct thread_info
*thr
)
4011 int pid
= ptid_get_pid (thr
->ptid
);
4012 long lwp
= ptid_get_lwp (thr
->ptid
);
4013 #define FORMAT "/proc/%d/task/%ld/comm"
4014 char buf
[sizeof (FORMAT
) + 30];
4016 char *result
= NULL
;
4018 snprintf (buf
, sizeof (buf
), FORMAT
, pid
, lwp
);
4019 comm_file
= gdb_fopen_cloexec (buf
, "r");
4022 /* Not exported by the kernel, so we define it here. */
4024 static char line
[COMM_LEN
+ 1];
4026 if (fgets (line
, sizeof (line
), comm_file
))
4028 char *nl
= strchr (line
, '\n');
4045 /* Accepts an integer PID; Returns a string representing a file that
4046 can be opened to get the symbols for the child process. */
4049 linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
)
4051 static char buf
[PATH_MAX
];
4052 char name
[PATH_MAX
];
4054 xsnprintf (name
, PATH_MAX
, "/proc/%d/exe", pid
);
4055 memset (buf
, 0, PATH_MAX
);
4056 if (readlink (name
, buf
, PATH_MAX
- 1) <= 0)
4062 /* Records the thread's register state for the corefile note
4066 linux_nat_collect_thread_registers (const struct regcache
*regcache
,
4067 ptid_t ptid
, bfd
*obfd
,
4068 char *note_data
, int *note_size
,
4069 enum gdb_signal stop_signal
)
4071 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
4072 const struct regset
*regset
;
4074 gdb_gregset_t gregs
;
4075 gdb_fpregset_t fpregs
;
4077 core_regset_p
= gdbarch_regset_from_core_section_p (gdbarch
);
4080 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg",
4082 != NULL
&& regset
->collect_regset
!= NULL
)
4083 regset
->collect_regset (regset
, regcache
, -1, &gregs
, sizeof (gregs
));
4085 fill_gregset (regcache
, &gregs
, -1);
4087 note_data
= (char *) elfcore_write_prstatus
4088 (obfd
, note_data
, note_size
, ptid_get_lwp (ptid
),
4089 gdb_signal_to_host (stop_signal
), &gregs
);
4092 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg2",
4094 != NULL
&& regset
->collect_regset
!= NULL
)
4095 regset
->collect_regset (regset
, regcache
, -1, &fpregs
, sizeof (fpregs
));
4097 fill_fpregset (regcache
, &fpregs
, -1);
4099 note_data
= (char *) elfcore_write_prfpreg (obfd
, note_data
, note_size
,
4100 &fpregs
, sizeof (fpregs
));
4105 /* Fills the "to_make_corefile_note" target vector. Builds the note
4106 section for a corefile, and returns it in a malloc buffer. */
4109 linux_nat_make_corefile_notes (struct target_ops
*self
,
4110 bfd
*obfd
, int *note_size
)
4112 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4113 converted to gdbarch_core_regset_sections, this function can go away. */
4114 return linux_make_corefile_notes (target_gdbarch (), obfd
, note_size
,
4115 linux_nat_collect_thread_registers
);
4118 /* Implement the to_xfer_partial interface for memory reads using the /proc
4119 filesystem. Because we can use a single read() call for /proc, this
4120 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4121 but it doesn't support writes. */
4123 static enum target_xfer_status
4124 linux_proc_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4125 const char *annex
, gdb_byte
*readbuf
,
4126 const gdb_byte
*writebuf
,
4127 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
4133 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
4136 /* Don't bother for one word. */
4137 if (len
< 3 * sizeof (long))
4138 return TARGET_XFER_EOF
;
4140 /* We could keep this file open and cache it - possibly one per
4141 thread. That requires some juggling, but is even faster. */
4142 xsnprintf (filename
, sizeof filename
, "/proc/%d/mem",
4143 ptid_get_pid (inferior_ptid
));
4144 fd
= gdb_open_cloexec (filename
, O_RDONLY
| O_LARGEFILE
, 0);
4146 return TARGET_XFER_EOF
;
4148 /* If pread64 is available, use it. It's faster if the kernel
4149 supports it (only one syscall), and it's 64-bit safe even on
4150 32-bit platforms (for instance, SPARC debugging a SPARC64
4153 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
4155 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
4164 return TARGET_XFER_EOF
;
4168 return TARGET_XFER_OK
;
4173 /* Enumerate spufs IDs for process PID. */
4175 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
4177 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
4179 LONGEST written
= 0;
4182 struct dirent
*entry
;
4184 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
4185 dir
= opendir (path
);
4190 while ((entry
= readdir (dir
)) != NULL
)
4196 fd
= atoi (entry
->d_name
);
4200 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
4201 if (stat (path
, &st
) != 0)
4203 if (!S_ISDIR (st
.st_mode
))
4206 if (statfs (path
, &stfs
) != 0)
4208 if (stfs
.f_type
!= SPUFS_MAGIC
)
4211 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
4213 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
4223 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4224 object type, using the /proc file system. */
4226 static enum target_xfer_status
4227 linux_proc_xfer_spu (struct target_ops
*ops
, enum target_object object
,
4228 const char *annex
, gdb_byte
*readbuf
,
4229 const gdb_byte
*writebuf
,
4230 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
4235 int pid
= ptid_get_pid (inferior_ptid
);
4240 return TARGET_XFER_E_IO
;
4243 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4246 return TARGET_XFER_E_IO
;
4248 return TARGET_XFER_EOF
;
4251 *xfered_len
= (ULONGEST
) l
;
4252 return TARGET_XFER_OK
;
4257 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4258 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4260 return TARGET_XFER_E_IO
;
4263 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4266 return TARGET_XFER_EOF
;
4270 ret
= write (fd
, writebuf
, (size_t) len
);
4272 ret
= read (fd
, readbuf
, (size_t) len
);
4277 return TARGET_XFER_E_IO
;
4279 return TARGET_XFER_EOF
;
4282 *xfered_len
= (ULONGEST
) ret
;
4283 return TARGET_XFER_OK
;
4288 /* Parse LINE as a signal set and add its set bits to SIGS. */
4291 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4293 int len
= strlen (line
) - 1;
4297 if (line
[len
] != '\n')
4298 error (_("Could not parse signal set: %s"), line
);
4306 if (*p
>= '0' && *p
<= '9')
4308 else if (*p
>= 'a' && *p
<= 'f')
4309 digit
= *p
- 'a' + 10;
4311 error (_("Could not parse signal set: %s"), line
);
4316 sigaddset (sigs
, signum
+ 1);
4318 sigaddset (sigs
, signum
+ 2);
4320 sigaddset (sigs
, signum
+ 3);
4322 sigaddset (sigs
, signum
+ 4);
4328 /* Find process PID's pending signals from /proc/pid/status and set
4332 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4333 sigset_t
*blocked
, sigset_t
*ignored
)
4336 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4337 struct cleanup
*cleanup
;
4339 sigemptyset (pending
);
4340 sigemptyset (blocked
);
4341 sigemptyset (ignored
);
4342 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4343 procfile
= gdb_fopen_cloexec (fname
, "r");
4344 if (procfile
== NULL
)
4345 error (_("Could not open %s"), fname
);
4346 cleanup
= make_cleanup_fclose (procfile
);
4348 while (fgets (buffer
, PATH_MAX
, procfile
) != NULL
)
4350 /* Normal queued signals are on the SigPnd line in the status
4351 file. However, 2.6 kernels also have a "shared" pending
4352 queue for delivering signals to a thread group, so check for
4355 Unfortunately some Red Hat kernels include the shared pending
4356 queue but not the ShdPnd status field. */
4358 if (strncmp (buffer
, "SigPnd:\t", 8) == 0)
4359 add_line_to_sigset (buffer
+ 8, pending
);
4360 else if (strncmp (buffer
, "ShdPnd:\t", 8) == 0)
4361 add_line_to_sigset (buffer
+ 8, pending
);
4362 else if (strncmp (buffer
, "SigBlk:\t", 8) == 0)
4363 add_line_to_sigset (buffer
+ 8, blocked
);
4364 else if (strncmp (buffer
, "SigIgn:\t", 8) == 0)
4365 add_line_to_sigset (buffer
+ 8, ignored
);
4368 do_cleanups (cleanup
);
4371 static enum target_xfer_status
4372 linux_nat_xfer_osdata (struct target_ops
*ops
, enum target_object object
,
4373 const char *annex
, gdb_byte
*readbuf
,
4374 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4375 ULONGEST
*xfered_len
)
4377 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4379 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4380 if (*xfered_len
== 0)
4381 return TARGET_XFER_EOF
;
4383 return TARGET_XFER_OK
;
4386 static enum target_xfer_status
4387 linux_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4388 const char *annex
, gdb_byte
*readbuf
,
4389 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4390 ULONGEST
*xfered_len
)
4392 enum target_xfer_status xfer
;
4394 if (object
== TARGET_OBJECT_AUXV
)
4395 return memory_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4396 offset
, len
, xfered_len
);
4398 if (object
== TARGET_OBJECT_OSDATA
)
4399 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4400 offset
, len
, xfered_len
);
4402 if (object
== TARGET_OBJECT_SPU
)
4403 return linux_proc_xfer_spu (ops
, object
, annex
, readbuf
, writebuf
,
4404 offset
, len
, xfered_len
);
4406 /* GDB calculates all the addresses in possibly larget width of the address.
4407 Address width needs to be masked before its final use - either by
4408 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4410 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4412 if (object
== TARGET_OBJECT_MEMORY
)
4414 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
4416 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
4417 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
4420 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4421 offset
, len
, xfered_len
);
4422 if (xfer
!= TARGET_XFER_EOF
)
4425 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4426 offset
, len
, xfered_len
);
4430 cleanup_target_stop (void *arg
)
4432 ptid_t
*ptid
= (ptid_t
*) arg
;
4434 gdb_assert (arg
!= NULL
);
4437 target_resume (*ptid
, 0, GDB_SIGNAL_0
);
4440 static VEC(static_tracepoint_marker_p
) *
4441 linux_child_static_tracepoint_markers_by_strid (struct target_ops
*self
,
4444 char s
[IPA_CMD_BUF_SIZE
];
4445 struct cleanup
*old_chain
;
4446 int pid
= ptid_get_pid (inferior_ptid
);
4447 VEC(static_tracepoint_marker_p
) *markers
= NULL
;
4448 struct static_tracepoint_marker
*marker
= NULL
;
4450 ptid_t ptid
= ptid_build (pid
, 0, 0);
4455 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4456 s
[sizeof ("qTfSTM")] = 0;
4458 agent_run_command (pid
, s
, strlen (s
) + 1);
4460 old_chain
= make_cleanup (free_current_marker
, &marker
);
4461 make_cleanup (cleanup_target_stop
, &ptid
);
4466 marker
= XCNEW (struct static_tracepoint_marker
);
4470 parse_static_tracepoint_marker_definition (p
, &p
, marker
);
4472 if (strid
== NULL
|| strcmp (strid
, marker
->str_id
) == 0)
4474 VEC_safe_push (static_tracepoint_marker_p
,
4480 release_static_tracepoint_marker (marker
);
4481 memset (marker
, 0, sizeof (*marker
));
4484 while (*p
++ == ','); /* comma-separated list */
4486 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4487 s
[sizeof ("qTsSTM")] = 0;
4488 agent_run_command (pid
, s
, strlen (s
) + 1);
4492 do_cleanups (old_chain
);
4497 /* Create a prototype generic GNU/Linux target. The client can override
4498 it with local methods. */
4501 linux_target_install_ops (struct target_ops
*t
)
4503 t
->to_insert_fork_catchpoint
= linux_child_insert_fork_catchpoint
;
4504 t
->to_remove_fork_catchpoint
= linux_child_remove_fork_catchpoint
;
4505 t
->to_insert_vfork_catchpoint
= linux_child_insert_vfork_catchpoint
;
4506 t
->to_remove_vfork_catchpoint
= linux_child_remove_vfork_catchpoint
;
4507 t
->to_insert_exec_catchpoint
= linux_child_insert_exec_catchpoint
;
4508 t
->to_remove_exec_catchpoint
= linux_child_remove_exec_catchpoint
;
4509 t
->to_set_syscall_catchpoint
= linux_child_set_syscall_catchpoint
;
4510 t
->to_pid_to_exec_file
= linux_child_pid_to_exec_file
;
4511 t
->to_post_startup_inferior
= linux_child_post_startup_inferior
;
4512 t
->to_post_attach
= linux_child_post_attach
;
4513 t
->to_follow_fork
= linux_child_follow_fork
;
4514 t
->to_make_corefile_notes
= linux_nat_make_corefile_notes
;
4516 super_xfer_partial
= t
->to_xfer_partial
;
4517 t
->to_xfer_partial
= linux_xfer_partial
;
4519 t
->to_static_tracepoint_markers_by_strid
4520 = linux_child_static_tracepoint_markers_by_strid
;
4526 struct target_ops
*t
;
4528 t
= inf_ptrace_target ();
4529 linux_target_install_ops (t
);
4535 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4537 struct target_ops
*t
;
4539 t
= inf_ptrace_trad_target (register_u_offset
);
4540 linux_target_install_ops (t
);
4545 /* target_is_async_p implementation. */
4548 linux_nat_is_async_p (struct target_ops
*ops
)
4550 /* NOTE: palves 2008-03-21: We're only async when the user requests
4551 it explicitly with the "set target-async" command.
4552 Someday, linux will always be async. */
4553 return target_async_permitted
;
4556 /* target_can_async_p implementation. */
4559 linux_nat_can_async_p (struct target_ops
*ops
)
4561 /* NOTE: palves 2008-03-21: We're only async when the user requests
4562 it explicitly with the "set target-async" command.
4563 Someday, linux will always be async. */
4564 return target_async_permitted
;
4568 linux_nat_supports_non_stop (struct target_ops
*self
)
4573 /* True if we want to support multi-process. To be removed when GDB
4574 supports multi-exec. */
4576 int linux_multi_process
= 1;
4579 linux_nat_supports_multi_process (struct target_ops
*self
)
4581 return linux_multi_process
;
4585 linux_nat_supports_disable_randomization (struct target_ops
*self
)
4587 #ifdef HAVE_PERSONALITY
4594 static int async_terminal_is_ours
= 1;
4596 /* target_terminal_inferior implementation.
4598 This is a wrapper around child_terminal_inferior to add async support. */
4601 linux_nat_terminal_inferior (struct target_ops
*self
)
4603 if (!target_is_async_p ())
4605 /* Async mode is disabled. */
4606 child_terminal_inferior (self
);
4610 child_terminal_inferior (self
);
4612 /* Calls to target_terminal_*() are meant to be idempotent. */
4613 if (!async_terminal_is_ours
)
4616 delete_file_handler (input_fd
);
4617 async_terminal_is_ours
= 0;
4621 /* target_terminal_ours implementation.
4623 This is a wrapper around child_terminal_ours to add async support (and
4624 implement the target_terminal_ours vs target_terminal_ours_for_output
4625 distinction). child_terminal_ours is currently no different than
4626 child_terminal_ours_for_output.
4627 We leave target_terminal_ours_for_output alone, leaving it to
4628 child_terminal_ours_for_output. */
4631 linux_nat_terminal_ours (struct target_ops
*self
)
4633 if (!target_is_async_p ())
4635 /* Async mode is disabled. */
4636 child_terminal_ours (self
);
4640 /* GDB should never give the terminal to the inferior if the
4641 inferior is running in the background (run&, continue&, etc.),
4642 but claiming it sure should. */
4643 child_terminal_ours (self
);
4645 if (async_terminal_is_ours
)
4648 clear_sigint_trap ();
4649 add_file_handler (input_fd
, stdin_event_handler
, 0);
4650 async_terminal_is_ours
= 1;
4653 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4655 static void *async_client_context
;
4657 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4658 so we notice when any child changes state, and notify the
4659 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4660 above to wait for the arrival of a SIGCHLD. */
4663 sigchld_handler (int signo
)
4665 int old_errno
= errno
;
4667 if (debug_linux_nat
)
4668 ui_file_write_async_safe (gdb_stdlog
,
4669 "sigchld\n", sizeof ("sigchld\n") - 1);
4671 if (signo
== SIGCHLD
4672 && linux_nat_event_pipe
[0] != -1)
4673 async_file_mark (); /* Let the event loop know that there are
4674 events to handle. */
4679 /* Callback registered with the target events file descriptor. */
4682 handle_target_event (int error
, gdb_client_data client_data
)
4684 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4687 /* Create/destroy the target events pipe. Returns previous state. */
4690 linux_async_pipe (int enable
)
4692 int previous
= (linux_nat_event_pipe
[0] != -1);
4694 if (previous
!= enable
)
4698 /* Block child signals while we create/destroy the pipe, as
4699 their handler writes to it. */
4700 block_child_signals (&prev_mask
);
4704 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4705 internal_error (__FILE__
, __LINE__
,
4706 "creating event pipe failed.");
4708 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4709 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4713 close (linux_nat_event_pipe
[0]);
4714 close (linux_nat_event_pipe
[1]);
4715 linux_nat_event_pipe
[0] = -1;
4716 linux_nat_event_pipe
[1] = -1;
4719 restore_child_signals_mask (&prev_mask
);
4725 /* target_async implementation. */
4728 linux_nat_async (struct target_ops
*ops
,
4729 void (*callback
) (enum inferior_event_type event_type
,
4733 if (callback
!= NULL
)
4735 async_client_callback
= callback
;
4736 async_client_context
= context
;
4737 if (!linux_async_pipe (1))
4739 add_file_handler (linux_nat_event_pipe
[0],
4740 handle_target_event
, NULL
);
4741 /* There may be pending events to handle. Tell the event loop
4748 async_client_callback
= callback
;
4749 async_client_context
= context
;
4750 delete_file_handler (linux_nat_event_pipe
[0]);
4751 linux_async_pipe (0);
4756 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4760 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4764 if (debug_linux_nat
)
4765 fprintf_unfiltered (gdb_stdlog
,
4766 "LNSL: running -> suspending %s\n",
4767 target_pid_to_str (lwp
->ptid
));
4770 if (lwp
->last_resume_kind
== resume_stop
)
4772 if (debug_linux_nat
)
4773 fprintf_unfiltered (gdb_stdlog
,
4774 "linux-nat: already stopping LWP %ld at "
4776 ptid_get_lwp (lwp
->ptid
));
4780 stop_callback (lwp
, NULL
);
4781 lwp
->last_resume_kind
= resume_stop
;
4785 /* Already known to be stopped; do nothing. */
4787 if (debug_linux_nat
)
4789 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4790 fprintf_unfiltered (gdb_stdlog
,
4791 "LNSL: already stopped/stop_requested %s\n",
4792 target_pid_to_str (lwp
->ptid
));
4794 fprintf_unfiltered (gdb_stdlog
,
4795 "LNSL: already stopped/no "
4796 "stop_requested yet %s\n",
4797 target_pid_to_str (lwp
->ptid
));
4804 linux_nat_stop (struct target_ops
*self
, ptid_t ptid
)
4807 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4809 linux_ops
->to_stop (linux_ops
, ptid
);
4813 linux_nat_close (struct target_ops
*self
)
4815 /* Unregister from the event loop. */
4816 if (linux_nat_is_async_p (NULL
))
4817 linux_nat_async (NULL
, NULL
, 0);
4819 if (linux_ops
->to_close
)
4820 linux_ops
->to_close (linux_ops
);
4825 /* When requests are passed down from the linux-nat layer to the
4826 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4827 used. The address space pointer is stored in the inferior object,
4828 but the common code that is passed such ptid can't tell whether
4829 lwpid is a "main" process id or not (it assumes so). We reverse
4830 look up the "main" process id from the lwp here. */
4832 static struct address_space
*
4833 linux_nat_thread_address_space (struct target_ops
*t
, ptid_t ptid
)
4835 struct lwp_info
*lwp
;
4836 struct inferior
*inf
;
4839 pid
= ptid_get_lwp (ptid
);
4840 if (ptid_get_lwp (ptid
) == 0)
4842 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4844 lwp
= find_lwp_pid (ptid
);
4845 pid
= ptid_get_pid (lwp
->ptid
);
4849 /* A (pid,lwpid,0) ptid. */
4850 pid
= ptid_get_pid (ptid
);
4853 inf
= find_inferior_pid (pid
);
4854 gdb_assert (inf
!= NULL
);
4858 /* Return the cached value of the processor core for thread PTID. */
4861 linux_nat_core_of_thread (struct target_ops
*ops
, ptid_t ptid
)
4863 struct lwp_info
*info
= find_lwp_pid (ptid
);
4871 linux_nat_add_target (struct target_ops
*t
)
4873 /* Save the provided single-threaded target. We save this in a separate
4874 variable because another target we've inherited from (e.g. inf-ptrace)
4875 may have saved a pointer to T; we want to use it for the final
4876 process stratum target. */
4877 linux_ops_saved
= *t
;
4878 linux_ops
= &linux_ops_saved
;
4880 /* Override some methods for multithreading. */
4881 t
->to_create_inferior
= linux_nat_create_inferior
;
4882 t
->to_attach
= linux_nat_attach
;
4883 t
->to_detach
= linux_nat_detach
;
4884 t
->to_resume
= linux_nat_resume
;
4885 t
->to_wait
= linux_nat_wait
;
4886 t
->to_pass_signals
= linux_nat_pass_signals
;
4887 t
->to_xfer_partial
= linux_nat_xfer_partial
;
4888 t
->to_kill
= linux_nat_kill
;
4889 t
->to_mourn_inferior
= linux_nat_mourn_inferior
;
4890 t
->to_thread_alive
= linux_nat_thread_alive
;
4891 t
->to_pid_to_str
= linux_nat_pid_to_str
;
4892 t
->to_thread_name
= linux_nat_thread_name
;
4893 t
->to_has_thread_control
= tc_schedlock
;
4894 t
->to_thread_address_space
= linux_nat_thread_address_space
;
4895 t
->to_stopped_by_watchpoint
= linux_nat_stopped_by_watchpoint
;
4896 t
->to_stopped_data_address
= linux_nat_stopped_data_address
;
4898 t
->to_can_async_p
= linux_nat_can_async_p
;
4899 t
->to_is_async_p
= linux_nat_is_async_p
;
4900 t
->to_supports_non_stop
= linux_nat_supports_non_stop
;
4901 t
->to_async
= linux_nat_async
;
4902 t
->to_terminal_inferior
= linux_nat_terminal_inferior
;
4903 t
->to_terminal_ours
= linux_nat_terminal_ours
;
4905 super_close
= t
->to_close
;
4906 t
->to_close
= linux_nat_close
;
4908 /* Methods for non-stop support. */
4909 t
->to_stop
= linux_nat_stop
;
4911 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
4913 t
->to_supports_disable_randomization
4914 = linux_nat_supports_disable_randomization
;
4916 t
->to_core_of_thread
= linux_nat_core_of_thread
;
4918 /* We don't change the stratum; this target will sit at
4919 process_stratum and thread_db will set at thread_stratum. This
4920 is a little strange, since this is a multi-threaded-capable
4921 target, but we want to be on the stack below thread_db, and we
4922 also want to be used for single-threaded processes. */
4927 /* Register a method to call whenever a new thread is attached. */
4929 linux_nat_set_new_thread (struct target_ops
*t
,
4930 void (*new_thread
) (struct lwp_info
*))
4932 /* Save the pointer. We only support a single registered instance
4933 of the GNU/Linux native target, so we do not need to map this to
4935 linux_nat_new_thread
= new_thread
;
4938 /* See declaration in linux-nat.h. */
4941 linux_nat_set_new_fork (struct target_ops
*t
,
4942 linux_nat_new_fork_ftype
*new_fork
)
4944 /* Save the pointer. */
4945 linux_nat_new_fork
= new_fork
;
4948 /* See declaration in linux-nat.h. */
4951 linux_nat_set_forget_process (struct target_ops
*t
,
4952 linux_nat_forget_process_ftype
*fn
)
4954 /* Save the pointer. */
4955 linux_nat_forget_process_hook
= fn
;
4958 /* See declaration in linux-nat.h. */
4961 linux_nat_forget_process (pid_t pid
)
4963 if (linux_nat_forget_process_hook
!= NULL
)
4964 linux_nat_forget_process_hook (pid
);
4967 /* Register a method that converts a siginfo object between the layout
4968 that ptrace returns, and the layout in the architecture of the
4971 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4972 int (*siginfo_fixup
) (siginfo_t
*,
4976 /* Save the pointer. */
4977 linux_nat_siginfo_fixup
= siginfo_fixup
;
4980 /* Register a method to call prior to resuming a thread. */
4983 linux_nat_set_prepare_to_resume (struct target_ops
*t
,
4984 void (*prepare_to_resume
) (struct lwp_info
*))
4986 /* Save the pointer. */
4987 linux_nat_prepare_to_resume
= prepare_to_resume
;
4990 /* See linux-nat.h. */
4993 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4997 pid
= ptid_get_lwp (ptid
);
4999 pid
= ptid_get_pid (ptid
);
5002 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
5005 memset (siginfo
, 0, sizeof (*siginfo
));
5011 /* Provide a prototype to silence -Wmissing-prototypes. */
5012 extern initialize_file_ftype _initialize_linux_nat
;
5015 _initialize_linux_nat (void)
5017 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
5018 &debug_linux_nat
, _("\
5019 Set debugging of GNU/Linux lwp module."), _("\
5020 Show debugging of GNU/Linux lwp module."), _("\
5021 Enables printf debugging output."),
5023 show_debug_linux_nat
,
5024 &setdebuglist
, &showdebuglist
);
5026 /* Save this mask as the default. */
5027 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
5029 /* Install a SIGCHLD handler. */
5030 sigchld_action
.sa_handler
= sigchld_handler
;
5031 sigemptyset (&sigchld_action
.sa_mask
);
5032 sigchld_action
.sa_flags
= SA_RESTART
;
5034 /* Make it the default. */
5035 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
5037 /* Make sure we don't block SIGCHLD during a sigsuspend. */
5038 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
5039 sigdelset (&suspend_mask
, SIGCHLD
);
5041 sigemptyset (&blocked_mask
);
5043 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
5044 support read-only process state. */
5045 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
5046 | PTRACE_O_TRACEVFORKDONE
5047 | PTRACE_O_TRACEVFORK
5048 | PTRACE_O_TRACEFORK
5049 | PTRACE_O_TRACEEXEC
);
5053 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5054 the GNU/Linux Threads library and therefore doesn't really belong
5057 /* Read variable NAME in the target and return its value if found.
5058 Otherwise return zero. It is assumed that the type of the variable
5062 get_signo (const char *name
)
5064 struct bound_minimal_symbol ms
;
5067 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
5068 if (ms
.minsym
== NULL
)
5071 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
5072 sizeof (signo
)) != 0)
5078 /* Return the set of signals used by the threads library in *SET. */
5081 lin_thread_get_thread_signals (sigset_t
*set
)
5083 struct sigaction action
;
5084 int restart
, cancel
;
5086 sigemptyset (&blocked_mask
);
5089 restart
= get_signo ("__pthread_sig_restart");
5090 cancel
= get_signo ("__pthread_sig_cancel");
5092 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5093 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5094 not provide any way for the debugger to query the signal numbers -
5095 fortunately they don't change! */
5098 restart
= __SIGRTMIN
;
5101 cancel
= __SIGRTMIN
+ 1;
5103 sigaddset (set
, restart
);
5104 sigaddset (set
, cancel
);
5106 /* The GNU/Linux Threads library makes terminating threads send a
5107 special "cancel" signal instead of SIGCHLD. Make sure we catch
5108 those (to prevent them from terminating GDB itself, which is
5109 likely to be their default action) and treat them the same way as
5112 action
.sa_handler
= sigchld_handler
;
5113 sigemptyset (&action
.sa_mask
);
5114 action
.sa_flags
= SA_RESTART
;
5115 sigaction (cancel
, &action
, NULL
);
5117 /* We block the "cancel" signal throughout this code ... */
5118 sigaddset (&blocked_mask
, cancel
);
5119 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
5121 /* ... except during a sigsuspend. */
5122 sigdelset (&suspend_mask
, cancel
);