1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2015 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
27 #ifdef HAVE_TKILL_SYSCALL
29 #include <sys/syscall.h>
31 #include <sys/ptrace.h>
32 #include "linux-nat.h"
33 #include "nat/linux-ptrace.h"
34 #include "nat/linux-procfs.h"
35 #include "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"
59 #include "nat/linux-osdata.h"
60 #include "linux-tdep.h"
63 #include "tracepoint.h"
65 #include "target-descriptions.h"
66 #include "filestuff.h"
70 #define SPUFS_MAGIC 0x23c9b64e
73 #ifdef HAVE_PERSONALITY
74 # include <sys/personality.h>
75 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
76 # define ADDR_NO_RANDOMIZE 0x0040000
78 #endif /* HAVE_PERSONALITY */
80 /* This comment documents high-level logic of this file.
82 Waiting for events in sync mode
83 ===============================
85 When waiting for an event in a specific thread, we just use waitpid, passing
86 the specific pid, and not passing WNOHANG.
88 When waiting for an event in all threads, waitpid is not quite good. Prior to
89 version 2.4, Linux can either wait for event in main thread, or in secondary
90 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
91 miss an event. The solution is to use non-blocking waitpid, together with
92 sigsuspend. First, we use non-blocking waitpid to get an event in the main
93 process, if any. Second, we use non-blocking waitpid with the __WCLONED
94 flag to check for events in cloned processes. If nothing is found, we use
95 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
96 happened to a child process -- and SIGCHLD will be delivered both for events
97 in main debugged process and in cloned processes. As soon as we know there's
98 an event, we get back to calling nonblocking waitpid with and without
101 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
102 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
103 blocked, the signal becomes pending and sigsuspend immediately
104 notices it and returns.
106 Waiting for events in async mode
107 ================================
109 In async mode, GDB should always be ready to handle both user input
110 and target events, so neither blocking waitpid nor sigsuspend are
111 viable options. Instead, we should asynchronously notify the GDB main
112 event loop whenever there's an unprocessed event from the target. We
113 detect asynchronous target events by handling SIGCHLD signals. To
114 notify the event loop about target events, the self-pipe trick is used
115 --- a pipe is registered as waitable event source in the event loop,
116 the event loop select/poll's on the read end of this pipe (as well on
117 other event sources, e.g., stdin), and the SIGCHLD handler writes a
118 byte to this pipe. This is more portable than relying on
119 pselect/ppoll, since on kernels that lack those syscalls, libc
120 emulates them with select/poll+sigprocmask, and that is racy
121 (a.k.a. plain broken).
123 Obviously, if we fail to notify the event loop if there's a target
124 event, it's bad. OTOH, if we notify the event loop when there's no
125 event from the target, linux_nat_wait will detect that there's no real
126 event to report, and return event of type TARGET_WAITKIND_IGNORE.
127 This is mostly harmless, but it will waste time and is better avoided.
129 The main design point is that every time GDB is outside linux-nat.c,
130 we have a SIGCHLD handler installed that is called when something
131 happens to the target and notifies the GDB event loop. Whenever GDB
132 core decides to handle the event, and calls into linux-nat.c, we
133 process things as in sync mode, except that the we never block in
136 While processing an event, we may end up momentarily blocked in
137 waitpid calls. Those waitpid calls, while blocking, are guarantied to
138 return quickly. E.g., in all-stop mode, before reporting to the core
139 that an LWP hit a breakpoint, all LWPs are stopped by sending them
140 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
141 Note that this is different from blocking indefinitely waiting for the
142 next event --- here, we're already handling an event.
147 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
148 signal is not entirely significant; we just need for a signal to be delivered,
149 so that we can intercept it. SIGSTOP's advantage is that it can not be
150 blocked. A disadvantage is that it is not a real-time signal, so it can only
151 be queued once; we do not keep track of other sources of SIGSTOP.
153 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
154 use them, because they have special behavior when the signal is generated -
155 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
156 kills the entire thread group.
158 A delivered SIGSTOP would stop the entire thread group, not just the thread we
159 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
160 cancel it (by PTRACE_CONT without passing SIGSTOP).
162 We could use a real-time signal instead. This would solve those problems; we
163 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
164 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
165 generates it, and there are races with trying to find a signal that is not
169 #define O_LARGEFILE 0
172 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
173 the use of the multi-threaded target. */
174 static struct target_ops
*linux_ops
;
175 static struct target_ops linux_ops_saved
;
177 /* The method to call, if any, when a new thread is attached. */
178 static void (*linux_nat_new_thread
) (struct lwp_info
*);
180 /* The method to call, if any, when a new fork is attached. */
181 static linux_nat_new_fork_ftype
*linux_nat_new_fork
;
183 /* The method to call, if any, when a process is no longer
185 static linux_nat_forget_process_ftype
*linux_nat_forget_process_hook
;
187 /* Hook to call prior to resuming a thread. */
188 static void (*linux_nat_prepare_to_resume
) (struct lwp_info
*);
190 /* The method to call, if any, when the siginfo object needs to be
191 converted between the layout returned by ptrace, and the layout in
192 the architecture of the inferior. */
193 static int (*linux_nat_siginfo_fixup
) (siginfo_t
*,
197 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
198 Called by our to_xfer_partial. */
199 static target_xfer_partial_ftype
*super_xfer_partial
;
201 /* The saved to_close method, inherited from inf-ptrace.c.
202 Called by our to_close. */
203 static void (*super_close
) (struct target_ops
*);
205 static unsigned int debug_linux_nat
;
207 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
208 struct cmd_list_element
*c
, const char *value
)
210 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
214 struct simple_pid_list
218 struct simple_pid_list
*next
;
220 struct simple_pid_list
*stopped_pids
;
222 /* Async mode support. */
224 /* The read/write ends of the pipe registered as waitable file in the
226 static int linux_nat_event_pipe
[2] = { -1, -1 };
228 /* Flush the event pipe. */
231 async_file_flush (void)
238 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
240 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
243 /* Put something (anything, doesn't matter what, or how much) in event
244 pipe, so that the select/poll in the event-loop realizes we have
245 something to process. */
248 async_file_mark (void)
252 /* It doesn't really matter what the pipe contains, as long we end
253 up with something in it. Might as well flush the previous
259 ret
= write (linux_nat_event_pipe
[1], "+", 1);
261 while (ret
== -1 && errno
== EINTR
);
263 /* Ignore EAGAIN. If the pipe is full, the event loop will already
264 be awakened anyway. */
267 static int kill_lwp (int lwpid
, int signo
);
269 static int stop_callback (struct lwp_info
*lp
, void *data
);
271 static void block_child_signals (sigset_t
*prev_mask
);
272 static void restore_child_signals_mask (sigset_t
*prev_mask
);
275 static struct lwp_info
*add_lwp (ptid_t ptid
);
276 static void purge_lwp_list (int pid
);
277 static void delete_lwp (ptid_t ptid
);
278 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
280 static int lwp_status_pending_p (struct lwp_info
*lp
);
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
328 ATTACHED should be nonzero iff we attached to the inferior. */
331 linux_init_ptrace (pid_t pid
, int attached
)
333 linux_enable_event_reporting (pid
, attached
);
334 linux_ptrace_init_warnings ();
338 linux_child_post_attach (struct target_ops
*self
, int pid
)
340 linux_init_ptrace (pid
, 1);
344 linux_child_post_startup_inferior (struct target_ops
*self
, ptid_t ptid
)
346 linux_init_ptrace (ptid_get_pid (ptid
), 0);
349 /* Return the number of known LWPs in the tgid given by PID. */
357 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
358 if (ptid_get_pid (lp
->ptid
) == pid
)
364 /* Call delete_lwp with prototype compatible for make_cleanup. */
367 delete_lwp_cleanup (void *lp_voidp
)
369 struct lwp_info
*lp
= lp_voidp
;
371 delete_lwp (lp
->ptid
);
374 /* Target hook for follow_fork. On entry inferior_ptid must be the
375 ptid of the followed inferior. At return, inferior_ptid will be
379 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
,
384 struct lwp_info
*child_lp
= NULL
;
385 int status
= W_STOPCODE (0);
386 struct cleanup
*old_chain
;
388 int parent_pid
, child_pid
;
390 has_vforked
= (inferior_thread ()->pending_follow
.kind
391 == TARGET_WAITKIND_VFORKED
);
392 parent_pid
= ptid_get_lwp (inferior_ptid
);
394 parent_pid
= ptid_get_pid (inferior_ptid
);
396 = ptid_get_pid (inferior_thread ()->pending_follow
.value
.related_pid
);
399 /* We're already attached to the parent, by default. */
400 old_chain
= save_inferior_ptid ();
401 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
402 child_lp
= add_lwp (inferior_ptid
);
403 child_lp
->stopped
= 1;
404 child_lp
->last_resume_kind
= resume_stop
;
406 /* Detach new forked process? */
409 make_cleanup (delete_lwp_cleanup
, child_lp
);
411 if (linux_nat_prepare_to_resume
!= NULL
)
412 linux_nat_prepare_to_resume (child_lp
);
414 /* When debugging an inferior in an architecture that supports
415 hardware single stepping on a kernel without commit
416 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
417 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
418 set if the parent process had them set.
419 To work around this, single step the child process
420 once before detaching to clear the flags. */
422 if (!gdbarch_software_single_step_p (target_thread_architecture
425 linux_disable_event_reporting (child_pid
);
426 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
427 perror_with_name (_("Couldn't do single step"));
428 if (my_waitpid (child_pid
, &status
, 0) < 0)
429 perror_with_name (_("Couldn't wait vfork process"));
432 if (WIFSTOPPED (status
))
436 signo
= WSTOPSIG (status
);
438 && !signal_pass_state (gdb_signal_from_host (signo
)))
440 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
443 /* Resets value of inferior_ptid to parent ptid. */
444 do_cleanups (old_chain
);
448 /* Let the thread_db layer learn about this new process. */
449 check_for_thread_db ();
452 do_cleanups (old_chain
);
456 struct lwp_info
*parent_lp
;
458 parent_lp
= find_lwp_pid (pid_to_ptid (parent_pid
));
459 gdb_assert (linux_supports_tracefork () >= 0);
461 if (linux_supports_tracevforkdone ())
464 fprintf_unfiltered (gdb_stdlog
,
465 "LCFF: waiting for VFORK_DONE on %d\n",
467 parent_lp
->stopped
= 1;
469 /* We'll handle the VFORK_DONE event like any other
470 event, in target_wait. */
474 /* We can't insert breakpoints until the child has
475 finished with the shared memory region. We need to
476 wait until that happens. Ideal would be to just
478 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
479 - waitpid (parent_pid, &status, __WALL);
480 However, most architectures can't handle a syscall
481 being traced on the way out if it wasn't traced on
484 We might also think to loop, continuing the child
485 until it exits or gets a SIGTRAP. One problem is
486 that the child might call ptrace with PTRACE_TRACEME.
488 There's no simple and reliable way to figure out when
489 the vforked child will be done with its copy of the
490 shared memory. We could step it out of the syscall,
491 two instructions, let it go, and then single-step the
492 parent once. When we have hardware single-step, this
493 would work; with software single-step it could still
494 be made to work but we'd have to be able to insert
495 single-step breakpoints in the child, and we'd have
496 to insert -just- the single-step breakpoint in the
497 parent. Very awkward.
499 In the end, the best we can do is to make sure it
500 runs for a little while. Hopefully it will be out of
501 range of any breakpoints we reinsert. Usually this
502 is only the single-step breakpoint at vfork's return
506 fprintf_unfiltered (gdb_stdlog
,
507 "LCFF: no VFORK_DONE "
508 "support, sleeping a bit\n");
512 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
513 and leave it pending. The next linux_nat_resume call
514 will notice a pending event, and bypasses actually
515 resuming the inferior. */
516 parent_lp
->status
= 0;
517 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
518 parent_lp
->stopped
= 1;
520 /* If we're in async mode, need to tell the event loop
521 there's something here to process. */
522 if (target_can_async_p ())
529 struct lwp_info
*child_lp
;
531 child_lp
= add_lwp (inferior_ptid
);
532 child_lp
->stopped
= 1;
533 child_lp
->last_resume_kind
= resume_stop
;
535 /* Let the thread_db layer learn about this new process. */
536 check_for_thread_db ();
544 linux_child_insert_fork_catchpoint (struct target_ops
*self
, int pid
)
546 return !linux_supports_tracefork ();
550 linux_child_remove_fork_catchpoint (struct target_ops
*self
, int pid
)
556 linux_child_insert_vfork_catchpoint (struct target_ops
*self
, int pid
)
558 return !linux_supports_tracefork ();
562 linux_child_remove_vfork_catchpoint (struct target_ops
*self
, int pid
)
568 linux_child_insert_exec_catchpoint (struct target_ops
*self
, int pid
)
570 return !linux_supports_tracefork ();
574 linux_child_remove_exec_catchpoint (struct target_ops
*self
, int pid
)
580 linux_child_set_syscall_catchpoint (struct target_ops
*self
,
581 int pid
, int needed
, int any_count
,
582 int table_size
, int *table
)
584 if (!linux_supports_tracesysgood ())
587 /* On GNU/Linux, we ignore the arguments. It means that we only
588 enable the syscall catchpoints, but do not disable them.
590 Also, we do not use the `table' information because we do not
591 filter system calls here. We let GDB do the logic for us. */
595 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
596 are processes sharing the same VM space. A multi-threaded process
597 is basically a group of such processes. However, such a grouping
598 is almost entirely a user-space issue; the kernel doesn't enforce
599 such a grouping at all (this might change in the future). In
600 general, we'll rely on the threads library (i.e. the GNU/Linux
601 Threads library) to provide such a grouping.
603 It is perfectly well possible to write a multi-threaded application
604 without the assistance of a threads library, by using the clone
605 system call directly. This module should be able to give some
606 rudimentary support for debugging such applications if developers
607 specify the CLONE_PTRACE flag in the clone system call, and are
608 using the Linux kernel 2.4 or above.
610 Note that there are some peculiarities in GNU/Linux that affect
613 - In general one should specify the __WCLONE flag to waitpid in
614 order to make it report events for any of the cloned processes
615 (and leave it out for the initial process). However, if a cloned
616 process has exited the exit status is only reported if the
617 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
618 we cannot use it since GDB must work on older systems too.
620 - When a traced, cloned process exits and is waited for by the
621 debugger, the kernel reassigns it to the original parent and
622 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
623 library doesn't notice this, which leads to the "zombie problem":
624 When debugged a multi-threaded process that spawns a lot of
625 threads will run out of processes, even if the threads exit,
626 because the "zombies" stay around. */
628 /* List of known LWPs. */
629 struct lwp_info
*lwp_list
;
632 /* Original signal mask. */
633 static sigset_t normal_mask
;
635 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
636 _initialize_linux_nat. */
637 static sigset_t suspend_mask
;
639 /* Signals to block to make that sigsuspend work. */
640 static sigset_t blocked_mask
;
642 /* SIGCHLD action. */
643 struct sigaction sigchld_action
;
645 /* Block child signals (SIGCHLD and linux threads signals), and store
646 the previous mask in PREV_MASK. */
649 block_child_signals (sigset_t
*prev_mask
)
651 /* Make sure SIGCHLD is blocked. */
652 if (!sigismember (&blocked_mask
, SIGCHLD
))
653 sigaddset (&blocked_mask
, SIGCHLD
);
655 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
658 /* Restore child signals mask, previously returned by
659 block_child_signals. */
662 restore_child_signals_mask (sigset_t
*prev_mask
)
664 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
667 /* Mask of signals to pass directly to the inferior. */
668 static sigset_t pass_mask
;
670 /* Update signals to pass to the inferior. */
672 linux_nat_pass_signals (struct target_ops
*self
,
673 int numsigs
, unsigned char *pass_signals
)
677 sigemptyset (&pass_mask
);
679 for (signo
= 1; signo
< NSIG
; signo
++)
681 int target_signo
= gdb_signal_from_host (signo
);
682 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
683 sigaddset (&pass_mask
, signo
);
689 /* Prototypes for local functions. */
690 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
691 static int linux_thread_alive (ptid_t ptid
);
692 static char *linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
);
696 /* Destroy and free LP. */
699 lwp_free (struct lwp_info
*lp
)
701 xfree (lp
->arch_private
);
705 /* Remove all LWPs belong to PID from the lwp list. */
708 purge_lwp_list (int pid
)
710 struct lwp_info
*lp
, *lpprev
, *lpnext
;
714 for (lp
= lwp_list
; lp
; lp
= lpnext
)
718 if (ptid_get_pid (lp
->ptid
) == pid
)
723 lpprev
->next
= lp
->next
;
732 /* Add the LWP specified by PTID to the list. PTID is the first LWP
733 in the process. Return a pointer to the structure describing the
736 This differs from add_lwp in that we don't let the arch specific
737 bits know about this new thread. Current clients of this callback
738 take the opportunity to install watchpoints in the new thread, and
739 we shouldn't do that for the first thread. If we're spawning a
740 child ("run"), the thread executes the shell wrapper first, and we
741 shouldn't touch it until it execs the program we want to debug.
742 For "attach", it'd be okay to call the callback, but it's not
743 necessary, because watchpoints can't yet have been inserted into
746 static struct lwp_info
*
747 add_initial_lwp (ptid_t ptid
)
751 gdb_assert (ptid_lwp_p (ptid
));
753 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
755 memset (lp
, 0, sizeof (struct lwp_info
));
757 lp
->last_resume_kind
= resume_continue
;
758 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
769 /* Add the LWP specified by PID to the list. Return a pointer to the
770 structure describing the new LWP. The LWP should already be
773 static struct lwp_info
*
774 add_lwp (ptid_t ptid
)
778 lp
= add_initial_lwp (ptid
);
780 /* Let the arch specific bits know about this new thread. Current
781 clients of this callback take the opportunity to install
782 watchpoints in the new thread. We don't do this for the first
783 thread though. See add_initial_lwp. */
784 if (linux_nat_new_thread
!= NULL
)
785 linux_nat_new_thread (lp
);
790 /* Remove the LWP specified by PID from the list. */
793 delete_lwp (ptid_t ptid
)
795 struct lwp_info
*lp
, *lpprev
;
799 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
800 if (ptid_equal (lp
->ptid
, ptid
))
807 lpprev
->next
= lp
->next
;
814 /* Return a pointer to the structure describing the LWP corresponding
815 to PID. If no corresponding LWP could be found, return NULL. */
817 static struct lwp_info
*
818 find_lwp_pid (ptid_t ptid
)
823 if (ptid_lwp_p (ptid
))
824 lwp
= ptid_get_lwp (ptid
);
826 lwp
= ptid_get_pid (ptid
);
828 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
829 if (lwp
== ptid_get_lwp (lp
->ptid
))
835 /* Call CALLBACK with its second argument set to DATA for every LWP in
836 the list. If CALLBACK returns 1 for a particular LWP, return a
837 pointer to the structure describing that LWP immediately.
838 Otherwise return NULL. */
841 iterate_over_lwps (ptid_t filter
,
842 int (*callback
) (struct lwp_info
*, void *),
845 struct lwp_info
*lp
, *lpnext
;
847 for (lp
= lwp_list
; lp
; lp
= lpnext
)
851 if (ptid_match (lp
->ptid
, filter
))
853 if ((*callback
) (lp
, data
))
861 /* Update our internal state when changing from one checkpoint to
862 another indicated by NEW_PTID. We can only switch single-threaded
863 applications, so we only create one new LWP, and the previous list
867 linux_nat_switch_fork (ptid_t new_ptid
)
871 purge_lwp_list (ptid_get_pid (inferior_ptid
));
873 lp
= add_lwp (new_ptid
);
876 /* This changes the thread's ptid while preserving the gdb thread
877 num. Also changes the inferior pid, while preserving the
879 thread_change_ptid (inferior_ptid
, new_ptid
);
881 /* We've just told GDB core that the thread changed target id, but,
882 in fact, it really is a different thread, with different register
884 registers_changed ();
887 /* Handle the exit of a single thread LP. */
890 exit_lwp (struct lwp_info
*lp
)
892 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
896 if (print_thread_events
)
897 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
899 delete_thread (lp
->ptid
);
902 delete_lwp (lp
->ptid
);
905 /* Wait for the LWP specified by LP, which we have just attached to.
906 Returns a wait status for that LWP, to cache. */
909 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
912 pid_t new_pid
, pid
= ptid_get_lwp (ptid
);
915 if (linux_proc_pid_is_stopped (pid
))
918 fprintf_unfiltered (gdb_stdlog
,
919 "LNPAW: Attaching to a stopped process\n");
921 /* The process is definitely stopped. It is in a job control
922 stop, unless the kernel predates the TASK_STOPPED /
923 TASK_TRACED distinction, in which case it might be in a
924 ptrace stop. Make sure it is in a ptrace stop; from there we
925 can kill it, signal it, et cetera.
927 First make sure there is a pending SIGSTOP. Since we are
928 already attached, the process can not transition from stopped
929 to running without a PTRACE_CONT; so we know this signal will
930 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
931 probably already in the queue (unless this kernel is old
932 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
933 is not an RT signal, it can only be queued once. */
934 kill_lwp (pid
, SIGSTOP
);
936 /* Finally, resume the stopped process. This will deliver the SIGSTOP
937 (or a higher priority signal, just like normal PTRACE_ATTACH). */
938 ptrace (PTRACE_CONT
, pid
, 0, 0);
941 /* Make sure the initial process is stopped. The user-level threads
942 layer might want to poke around in the inferior, and that won't
943 work if things haven't stabilized yet. */
944 new_pid
= my_waitpid (pid
, &status
, 0);
945 if (new_pid
== -1 && errno
== ECHILD
)
948 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
950 /* Try again with __WCLONE to check cloned processes. */
951 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
955 gdb_assert (pid
== new_pid
);
957 if (!WIFSTOPPED (status
))
959 /* The pid we tried to attach has apparently just exited. */
961 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
962 pid
, status_to_str (status
));
966 if (WSTOPSIG (status
) != SIGSTOP
)
970 fprintf_unfiltered (gdb_stdlog
,
971 "LNPAW: Received %s after attaching\n",
972 status_to_str (status
));
978 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
979 the new LWP could not be attached, or 1 if we're already auto
980 attached to this thread, but haven't processed the
981 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
982 its existance, without considering it an error. */
985 lin_lwp_attach_lwp (ptid_t ptid
)
990 gdb_assert (ptid_lwp_p (ptid
));
992 lp
= find_lwp_pid (ptid
);
993 lwpid
= ptid_get_lwp (ptid
);
995 /* We assume that we're already attached to any LWP that has an id
996 equal to the overall process id, and to any LWP that is already
997 in our list of LWPs. If we're not seeing exit events from threads
998 and we've had PID wraparound since we last tried to stop all threads,
999 this assumption might be wrong; fortunately, this is very unlikely
1001 if (lwpid
!= ptid_get_pid (ptid
) && lp
== NULL
)
1003 int status
, cloned
= 0, signalled
= 0;
1005 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1007 if (linux_supports_tracefork ())
1009 /* If we haven't stopped all threads when we get here,
1010 we may have seen a thread listed in thread_db's list,
1011 but not processed the PTRACE_EVENT_CLONE yet. If
1012 that's the case, ignore this new thread, and let
1013 normal event handling discover it later. */
1014 if (in_pid_list_p (stopped_pids
, lwpid
))
1016 /* We've already seen this thread stop, but we
1017 haven't seen the PTRACE_EVENT_CLONE extended
1026 /* See if we've got a stop for this new child
1027 pending. If so, we're already attached. */
1028 gdb_assert (lwpid
> 0);
1029 new_pid
= my_waitpid (lwpid
, &status
, WNOHANG
);
1030 if (new_pid
== -1 && errno
== ECHILD
)
1031 new_pid
= my_waitpid (lwpid
, &status
, __WCLONE
| WNOHANG
);
1034 if (WIFSTOPPED (status
))
1035 add_to_pid_list (&stopped_pids
, lwpid
, status
);
1041 /* If we fail to attach to the thread, issue a warning,
1042 but continue. One way this can happen is if thread
1043 creation is interrupted; as of Linux kernel 2.6.19, a
1044 bug may place threads in the thread list and then fail
1046 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1047 safe_strerror (errno
));
1051 if (debug_linux_nat
)
1052 fprintf_unfiltered (gdb_stdlog
,
1053 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1054 target_pid_to_str (ptid
));
1056 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1057 if (!WIFSTOPPED (status
))
1060 lp
= add_lwp (ptid
);
1062 lp
->cloned
= cloned
;
1063 lp
->signalled
= signalled
;
1064 if (WSTOPSIG (status
) != SIGSTOP
)
1067 lp
->status
= status
;
1070 target_post_attach (ptid_get_lwp (lp
->ptid
));
1072 if (debug_linux_nat
)
1074 fprintf_unfiltered (gdb_stdlog
,
1075 "LLAL: waitpid %s received %s\n",
1076 target_pid_to_str (ptid
),
1077 status_to_str (status
));
1082 /* We assume that the LWP representing the original process is
1083 already stopped. Mark it as stopped in the data structure
1084 that the GNU/linux ptrace layer uses to keep track of
1085 threads. Note that this won't have already been done since
1086 the main thread will have, we assume, been stopped by an
1087 attach from a different layer. */
1089 lp
= add_lwp (ptid
);
1093 lp
->last_resume_kind
= resume_stop
;
1098 linux_nat_create_inferior (struct target_ops
*ops
,
1099 char *exec_file
, char *allargs
, char **env
,
1102 #ifdef HAVE_PERSONALITY
1103 int personality_orig
= 0, personality_set
= 0;
1104 #endif /* HAVE_PERSONALITY */
1106 /* The fork_child mechanism is synchronous and calls target_wait, so
1107 we have to mask the async mode. */
1109 #ifdef HAVE_PERSONALITY
1110 if (disable_randomization
)
1113 personality_orig
= personality (0xffffffff);
1114 if (errno
== 0 && !(personality_orig
& ADDR_NO_RANDOMIZE
))
1116 personality_set
= 1;
1117 personality (personality_orig
| ADDR_NO_RANDOMIZE
);
1119 if (errno
!= 0 || (personality_set
1120 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE
)))
1121 warning (_("Error disabling address space randomization: %s"),
1122 safe_strerror (errno
));
1124 #endif /* HAVE_PERSONALITY */
1126 /* Make sure we report all signals during startup. */
1127 linux_nat_pass_signals (ops
, 0, NULL
);
1129 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1131 #ifdef HAVE_PERSONALITY
1132 if (personality_set
)
1135 personality (personality_orig
);
1137 warning (_("Error restoring address space randomization: %s"),
1138 safe_strerror (errno
));
1140 #endif /* HAVE_PERSONALITY */
1143 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1144 already attached. Returns true if a new LWP is found, false
1148 attach_proc_task_lwp_callback (ptid_t ptid
)
1150 struct lwp_info
*lp
;
1152 /* Ignore LWPs we're already attached to. */
1153 lp
= find_lwp_pid (ptid
);
1156 int lwpid
= ptid_get_lwp (ptid
);
1158 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1162 /* Be quiet if we simply raced with the thread exiting.
1163 EPERM is returned if the thread's task still exists, and
1164 is marked as exited or zombie, as well as other
1165 conditions, so in that case, confirm the status in
1166 /proc/PID/status. */
1168 || (err
== EPERM
&& linux_proc_pid_is_gone (lwpid
)))
1170 if (debug_linux_nat
)
1172 fprintf_unfiltered (gdb_stdlog
,
1173 "Cannot attach to lwp %d: "
1174 "thread is gone (%d: %s)\n",
1175 lwpid
, err
, safe_strerror (err
));
1180 warning (_("Cannot attach to lwp %d: %s\n"),
1182 linux_ptrace_attach_fail_reason_string (ptid
,
1188 if (debug_linux_nat
)
1189 fprintf_unfiltered (gdb_stdlog
,
1190 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1191 target_pid_to_str (ptid
));
1193 lp
= add_lwp (ptid
);
1196 /* The next time we wait for this LWP we'll see a SIGSTOP as
1197 PTRACE_ATTACH brings it to a halt. */
1200 /* We need to wait for a stop before being able to make the
1201 next ptrace call on this LWP. */
1202 lp
->must_set_ptrace_flags
= 1;
1211 linux_nat_attach (struct target_ops
*ops
, const char *args
, int from_tty
)
1213 struct lwp_info
*lp
;
1216 volatile struct gdb_exception ex
;
1218 /* Make sure we report all signals during attach. */
1219 linux_nat_pass_signals (ops
, 0, NULL
);
1221 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
1223 linux_ops
->to_attach (ops
, args
, from_tty
);
1227 pid_t pid
= parse_pid_to_attach (args
);
1228 struct buffer buffer
;
1229 char *message
, *buffer_s
;
1231 message
= xstrdup (ex
.message
);
1232 make_cleanup (xfree
, message
);
1234 buffer_init (&buffer
);
1235 linux_ptrace_attach_fail_reason (pid
, &buffer
);
1237 buffer_grow_str0 (&buffer
, "");
1238 buffer_s
= buffer_finish (&buffer
);
1239 make_cleanup (xfree
, buffer_s
);
1241 if (*buffer_s
!= '\0')
1242 throw_error (ex
.error
, "warning: %s\n%s", buffer_s
, message
);
1244 throw_error (ex
.error
, "%s", message
);
1247 /* The ptrace base target adds the main thread with (pid,0,0)
1248 format. Decorate it with lwp info. */
1249 ptid
= ptid_build (ptid_get_pid (inferior_ptid
),
1250 ptid_get_pid (inferior_ptid
),
1252 thread_change_ptid (inferior_ptid
, ptid
);
1254 /* Add the initial process as the first LWP to the list. */
1255 lp
= add_initial_lwp (ptid
);
1257 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1259 if (!WIFSTOPPED (status
))
1261 if (WIFEXITED (status
))
1263 int exit_code
= WEXITSTATUS (status
);
1265 target_terminal_ours ();
1266 target_mourn_inferior ();
1268 error (_("Unable to attach: program exited normally."));
1270 error (_("Unable to attach: program exited with code %d."),
1273 else if (WIFSIGNALED (status
))
1275 enum gdb_signal signo
;
1277 target_terminal_ours ();
1278 target_mourn_inferior ();
1280 signo
= gdb_signal_from_host (WTERMSIG (status
));
1281 error (_("Unable to attach: program terminated with signal "
1283 gdb_signal_to_name (signo
),
1284 gdb_signal_to_string (signo
));
1287 internal_error (__FILE__
, __LINE__
,
1288 _("unexpected status %d for PID %ld"),
1289 status
, (long) ptid_get_lwp (ptid
));
1294 /* Save the wait status to report later. */
1296 if (debug_linux_nat
)
1297 fprintf_unfiltered (gdb_stdlog
,
1298 "LNA: waitpid %ld, saving status %s\n",
1299 (long) ptid_get_pid (lp
->ptid
), status_to_str (status
));
1301 lp
->status
= status
;
1303 /* We must attach to every LWP. If /proc is mounted, use that to
1304 find them now. The inferior may be using raw clone instead of
1305 using pthreads. But even if it is using pthreads, thread_db
1306 walks structures in the inferior's address space to find the list
1307 of threads/LWPs, and those structures may well be corrupted.
1308 Note that once thread_db is loaded, we'll still use it to list
1309 threads and associate pthread info with each LWP. */
1310 linux_proc_attach_tgid_threads (ptid_get_pid (lp
->ptid
),
1311 attach_proc_task_lwp_callback
);
1313 if (target_can_async_p ())
1314 target_async (inferior_event_handler
, 0);
1317 /* Get pending status of LP. */
1319 get_pending_status (struct lwp_info
*lp
, int *status
)
1321 enum gdb_signal signo
= GDB_SIGNAL_0
;
1323 /* If we paused threads momentarily, we may have stored pending
1324 events in lp->status or lp->waitstatus (see stop_wait_callback),
1325 and GDB core hasn't seen any signal for those threads.
1326 Otherwise, the last signal reported to the core is found in the
1327 thread object's stop_signal.
1329 There's a corner case that isn't handled here at present. Only
1330 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1331 stop_signal make sense as a real signal to pass to the inferior.
1332 Some catchpoint related events, like
1333 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1334 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1335 those traps are debug API (ptrace in our case) related and
1336 induced; the inferior wouldn't see them if it wasn't being
1337 traced. Hence, we should never pass them to the inferior, even
1338 when set to pass state. Since this corner case isn't handled by
1339 infrun.c when proceeding with a signal, for consistency, neither
1340 do we handle it here (or elsewhere in the file we check for
1341 signal pass state). Normally SIGTRAP isn't set to pass state, so
1342 this is really a corner case. */
1344 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1345 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1346 else if (lp
->status
)
1347 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1348 else if (non_stop
&& !is_executing (lp
->ptid
))
1350 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1352 signo
= tp
->suspend
.stop_signal
;
1356 struct target_waitstatus last
;
1359 get_last_target_status (&last_ptid
, &last
);
1361 if (ptid_get_lwp (lp
->ptid
) == ptid_get_lwp (last_ptid
))
1363 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1365 signo
= tp
->suspend
.stop_signal
;
1371 if (signo
== GDB_SIGNAL_0
)
1373 if (debug_linux_nat
)
1374 fprintf_unfiltered (gdb_stdlog
,
1375 "GPT: lwp %s has no pending signal\n",
1376 target_pid_to_str (lp
->ptid
));
1378 else if (!signal_pass_state (signo
))
1380 if (debug_linux_nat
)
1381 fprintf_unfiltered (gdb_stdlog
,
1382 "GPT: lwp %s had signal %s, "
1383 "but it is in no pass state\n",
1384 target_pid_to_str (lp
->ptid
),
1385 gdb_signal_to_string (signo
));
1389 *status
= W_STOPCODE (gdb_signal_to_host (signo
));
1391 if (debug_linux_nat
)
1392 fprintf_unfiltered (gdb_stdlog
,
1393 "GPT: lwp %s has pending signal %s\n",
1394 target_pid_to_str (lp
->ptid
),
1395 gdb_signal_to_string (signo
));
1402 detach_callback (struct lwp_info
*lp
, void *data
)
1404 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1406 if (debug_linux_nat
&& lp
->status
)
1407 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1408 strsignal (WSTOPSIG (lp
->status
)),
1409 target_pid_to_str (lp
->ptid
));
1411 /* If there is a pending SIGSTOP, get rid of it. */
1414 if (debug_linux_nat
)
1415 fprintf_unfiltered (gdb_stdlog
,
1416 "DC: Sending SIGCONT to %s\n",
1417 target_pid_to_str (lp
->ptid
));
1419 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGCONT
);
1423 /* We don't actually detach from the LWP that has an id equal to the
1424 overall process id just yet. */
1425 if (ptid_get_lwp (lp
->ptid
) != ptid_get_pid (lp
->ptid
))
1429 /* Pass on any pending signal for this LWP. */
1430 get_pending_status (lp
, &status
);
1432 if (linux_nat_prepare_to_resume
!= NULL
)
1433 linux_nat_prepare_to_resume (lp
);
1435 if (ptrace (PTRACE_DETACH
, ptid_get_lwp (lp
->ptid
), 0,
1436 WSTOPSIG (status
)) < 0)
1437 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1438 safe_strerror (errno
));
1440 if (debug_linux_nat
)
1441 fprintf_unfiltered (gdb_stdlog
,
1442 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1443 target_pid_to_str (lp
->ptid
),
1444 strsignal (WSTOPSIG (status
)));
1446 delete_lwp (lp
->ptid
);
1453 linux_nat_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1457 struct lwp_info
*main_lwp
;
1459 pid
= ptid_get_pid (inferior_ptid
);
1461 /* Don't unregister from the event loop, as there may be other
1462 inferiors running. */
1464 /* Stop all threads before detaching. ptrace requires that the
1465 thread is stopped to sucessfully detach. */
1466 iterate_over_lwps (pid_to_ptid (pid
), stop_callback
, NULL
);
1467 /* ... and wait until all of them have reported back that
1468 they're no longer running. */
1469 iterate_over_lwps (pid_to_ptid (pid
), stop_wait_callback
, NULL
);
1471 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1473 /* Only the initial process should be left right now. */
1474 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid
)) == 1);
1476 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
1478 /* Pass on any pending signal for the last LWP. */
1479 if ((args
== NULL
|| *args
== '\0')
1480 && get_pending_status (main_lwp
, &status
) != -1
1481 && WIFSTOPPED (status
))
1485 /* Put the signal number in ARGS so that inf_ptrace_detach will
1486 pass it along with PTRACE_DETACH. */
1488 xsnprintf (tem
, 8, "%d", (int) WSTOPSIG (status
));
1490 if (debug_linux_nat
)
1491 fprintf_unfiltered (gdb_stdlog
,
1492 "LND: Sending signal %s to %s\n",
1494 target_pid_to_str (main_lwp
->ptid
));
1497 if (linux_nat_prepare_to_resume
!= NULL
)
1498 linux_nat_prepare_to_resume (main_lwp
);
1499 delete_lwp (main_lwp
->ptid
);
1501 if (forks_exist_p ())
1503 /* Multi-fork case. The current inferior_ptid is being detached
1504 from, but there are other viable forks to debug. Detach from
1505 the current fork, and context-switch to the first
1507 linux_fork_detach (args
, from_tty
);
1510 linux_ops
->to_detach (ops
, args
, from_tty
);
1513 /* Resume execution of the inferior process. If STEP is nonzero,
1514 single-step it. If SIGNAL is nonzero, give it that signal. */
1517 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1522 if (linux_nat_prepare_to_resume
!= NULL
)
1523 linux_nat_prepare_to_resume (lp
);
1524 /* Convert to something the lower layer understands. */
1525 ptid
= pid_to_ptid (ptid_get_lwp (lp
->ptid
));
1526 linux_ops
->to_resume (linux_ops
, ptid
, step
, signo
);
1527 lp
->stopped_by_watchpoint
= 0;
1529 registers_changed_ptid (lp
->ptid
);
1535 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1539 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
1541 if (inf
->vfork_child
!= NULL
)
1543 if (debug_linux_nat
)
1544 fprintf_unfiltered (gdb_stdlog
,
1545 "RC: Not resuming %s (vfork parent)\n",
1546 target_pid_to_str (lp
->ptid
));
1548 else if (!lwp_status_pending_p (lp
))
1550 if (debug_linux_nat
)
1551 fprintf_unfiltered (gdb_stdlog
,
1552 "RC: Resuming sibling %s, %s, %s\n",
1553 target_pid_to_str (lp
->ptid
),
1554 (signo
!= GDB_SIGNAL_0
1555 ? strsignal (gdb_signal_to_host (signo
))
1557 step
? "step" : "resume");
1559 linux_resume_one_lwp (lp
, step
, signo
);
1563 if (debug_linux_nat
)
1564 fprintf_unfiltered (gdb_stdlog
,
1565 "RC: Not resuming sibling %s (has pending)\n",
1566 target_pid_to_str (lp
->ptid
));
1571 if (debug_linux_nat
)
1572 fprintf_unfiltered (gdb_stdlog
,
1573 "RC: Not resuming sibling %s (not stopped)\n",
1574 target_pid_to_str (lp
->ptid
));
1578 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1579 Resume LWP with the last stop signal, if it is in pass state. */
1582 linux_nat_resume_callback (struct lwp_info
*lp
, void *except
)
1584 enum gdb_signal signo
= GDB_SIGNAL_0
;
1591 struct thread_info
*thread
;
1593 thread
= find_thread_ptid (lp
->ptid
);
1596 signo
= thread
->suspend
.stop_signal
;
1597 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1601 resume_lwp (lp
, 0, signo
);
1606 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1609 lp
->last_resume_kind
= resume_stop
;
1614 resume_set_callback (struct lwp_info
*lp
, void *data
)
1617 lp
->last_resume_kind
= resume_continue
;
1622 linux_nat_resume (struct target_ops
*ops
,
1623 ptid_t ptid
, int step
, enum gdb_signal signo
)
1625 struct lwp_info
*lp
;
1628 if (debug_linux_nat
)
1629 fprintf_unfiltered (gdb_stdlog
,
1630 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1631 step
? "step" : "resume",
1632 target_pid_to_str (ptid
),
1633 (signo
!= GDB_SIGNAL_0
1634 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1635 target_pid_to_str (inferior_ptid
));
1637 /* A specific PTID means `step only this process id'. */
1638 resume_many
= (ptid_equal (minus_one_ptid
, ptid
)
1639 || ptid_is_pid (ptid
));
1641 /* Mark the lwps we're resuming as resumed. */
1642 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1644 /* See if it's the current inferior that should be handled
1647 lp
= find_lwp_pid (inferior_ptid
);
1649 lp
= find_lwp_pid (ptid
);
1650 gdb_assert (lp
!= NULL
);
1652 /* Remember if we're stepping. */
1653 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1655 /* If we have a pending wait status for this thread, there is no
1656 point in resuming the process. But first make sure that
1657 linux_nat_wait won't preemptively handle the event - we
1658 should never take this short-circuit if we are going to
1659 leave LP running, since we have skipped resuming all the
1660 other threads. This bit of code needs to be synchronized
1661 with linux_nat_wait. */
1663 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1666 && WSTOPSIG (lp
->status
)
1667 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1669 if (debug_linux_nat
)
1670 fprintf_unfiltered (gdb_stdlog
,
1671 "LLR: Not short circuiting for ignored "
1672 "status 0x%x\n", lp
->status
);
1674 /* FIXME: What should we do if we are supposed to continue
1675 this thread with a signal? */
1676 gdb_assert (signo
== GDB_SIGNAL_0
);
1677 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1682 if (lwp_status_pending_p (lp
))
1684 /* FIXME: What should we do if we are supposed to continue
1685 this thread with a signal? */
1686 gdb_assert (signo
== GDB_SIGNAL_0
);
1688 if (debug_linux_nat
)
1689 fprintf_unfiltered (gdb_stdlog
,
1690 "LLR: Short circuiting for status 0x%x\n",
1693 if (target_can_async_p ())
1695 target_async (inferior_event_handler
, 0);
1696 /* Tell the event loop we have something to process. */
1703 iterate_over_lwps (ptid
, linux_nat_resume_callback
, lp
);
1705 linux_resume_one_lwp (lp
, step
, signo
);
1707 if (debug_linux_nat
)
1708 fprintf_unfiltered (gdb_stdlog
,
1709 "LLR: %s %s, %s (resume event thread)\n",
1710 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1711 target_pid_to_str (ptid
),
1712 (signo
!= GDB_SIGNAL_0
1713 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1715 if (target_can_async_p ())
1716 target_async (inferior_event_handler
, 0);
1719 /* Send a signal to an LWP. */
1722 kill_lwp (int lwpid
, int signo
)
1724 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1725 fails, then we are not using nptl threads and we should be using kill. */
1727 #ifdef HAVE_TKILL_SYSCALL
1729 static int tkill_failed
;
1736 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1737 if (errno
!= ENOSYS
)
1744 return kill (lwpid
, signo
);
1747 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1748 event, check if the core is interested in it: if not, ignore the
1749 event, and keep waiting; otherwise, we need to toggle the LWP's
1750 syscall entry/exit status, since the ptrace event itself doesn't
1751 indicate it, and report the trap to higher layers. */
1754 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1756 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1757 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1758 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, lp
->ptid
);
1762 /* If we're stopping threads, there's a SIGSTOP pending, which
1763 makes it so that the LWP reports an immediate syscall return,
1764 followed by the SIGSTOP. Skip seeing that "return" using
1765 PTRACE_CONT directly, and let stop_wait_callback collect the
1766 SIGSTOP. Later when the thread is resumed, a new syscall
1767 entry event. If we didn't do this (and returned 0), we'd
1768 leave a syscall entry pending, and our caller, by using
1769 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1770 itself. Later, when the user re-resumes this LWP, we'd see
1771 another syscall entry event and we'd mistake it for a return.
1773 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1774 (leaving immediately with LWP->signalled set, without issuing
1775 a PTRACE_CONT), it would still be problematic to leave this
1776 syscall enter pending, as later when the thread is resumed,
1777 it would then see the same syscall exit mentioned above,
1778 followed by the delayed SIGSTOP, while the syscall didn't
1779 actually get to execute. It seems it would be even more
1780 confusing to the user. */
1782 if (debug_linux_nat
)
1783 fprintf_unfiltered (gdb_stdlog
,
1784 "LHST: ignoring syscall %d "
1785 "for LWP %ld (stopping threads), "
1786 "resuming with PTRACE_CONT for SIGSTOP\n",
1788 ptid_get_lwp (lp
->ptid
));
1790 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1791 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
1796 if (catch_syscall_enabled ())
1798 /* Always update the entry/return state, even if this particular
1799 syscall isn't interesting to the core now. In async mode,
1800 the user could install a new catchpoint for this syscall
1801 between syscall enter/return, and we'll need to know to
1802 report a syscall return if that happens. */
1803 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1804 ? TARGET_WAITKIND_SYSCALL_RETURN
1805 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1807 if (catching_syscall_number (syscall_number
))
1809 /* Alright, an event to report. */
1810 ourstatus
->kind
= lp
->syscall_state
;
1811 ourstatus
->value
.syscall_number
= syscall_number
;
1813 if (debug_linux_nat
)
1814 fprintf_unfiltered (gdb_stdlog
,
1815 "LHST: stopping for %s of syscall %d"
1818 == TARGET_WAITKIND_SYSCALL_ENTRY
1819 ? "entry" : "return",
1821 ptid_get_lwp (lp
->ptid
));
1825 if (debug_linux_nat
)
1826 fprintf_unfiltered (gdb_stdlog
,
1827 "LHST: ignoring %s of syscall %d "
1829 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1830 ? "entry" : "return",
1832 ptid_get_lwp (lp
->ptid
));
1836 /* If we had been syscall tracing, and hence used PT_SYSCALL
1837 before on this LWP, it could happen that the user removes all
1838 syscall catchpoints before we get to process this event.
1839 There are two noteworthy issues here:
1841 - When stopped at a syscall entry event, resuming with
1842 PT_STEP still resumes executing the syscall and reports a
1845 - Only PT_SYSCALL catches syscall enters. If we last
1846 single-stepped this thread, then this event can't be a
1847 syscall enter. If we last single-stepped this thread, this
1848 has to be a syscall exit.
1850 The points above mean that the next resume, be it PT_STEP or
1851 PT_CONTINUE, can not trigger a syscall trace event. */
1852 if (debug_linux_nat
)
1853 fprintf_unfiltered (gdb_stdlog
,
1854 "LHST: caught syscall event "
1855 "with no syscall catchpoints."
1856 " %d for LWP %ld, ignoring\n",
1858 ptid_get_lwp (lp
->ptid
));
1859 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1862 /* The core isn't interested in this event. For efficiency, avoid
1863 stopping all threads only to have the core resume them all again.
1864 Since we're not stopping threads, if we're still syscall tracing
1865 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1866 subsequent syscall. Simply resume using the inf-ptrace layer,
1867 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1869 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1873 /* Handle a GNU/Linux extended wait response. If we see a clone
1874 event, we need to add the new LWP to our list (and not report the
1875 trap to higher layers). This function returns non-zero if the
1876 event should be ignored and we should wait again. If STOPPING is
1877 true, the new LWP remains stopped, otherwise it is continued. */
1880 linux_handle_extended_wait (struct lwp_info
*lp
, int status
,
1883 int pid
= ptid_get_lwp (lp
->ptid
);
1884 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1885 int event
= linux_ptrace_get_extended_event (status
);
1887 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1888 || event
== PTRACE_EVENT_CLONE
)
1890 unsigned long new_pid
;
1893 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1895 /* If we haven't already seen the new PID stop, wait for it now. */
1896 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1898 /* The new child has a pending SIGSTOP. We can't affect it until it
1899 hits the SIGSTOP, but we're already attached. */
1900 ret
= my_waitpid (new_pid
, &status
,
1901 (event
== PTRACE_EVENT_CLONE
) ? __WCLONE
: 0);
1903 perror_with_name (_("waiting for new child"));
1904 else if (ret
!= new_pid
)
1905 internal_error (__FILE__
, __LINE__
,
1906 _("wait returned unexpected PID %d"), ret
);
1907 else if (!WIFSTOPPED (status
))
1908 internal_error (__FILE__
, __LINE__
,
1909 _("wait returned unexpected status 0x%x"), status
);
1912 ourstatus
->value
.related_pid
= ptid_build (new_pid
, new_pid
, 0);
1914 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1916 /* The arch-specific native code may need to know about new
1917 forks even if those end up never mapped to an
1919 if (linux_nat_new_fork
!= NULL
)
1920 linux_nat_new_fork (lp
, new_pid
);
1923 if (event
== PTRACE_EVENT_FORK
1924 && linux_fork_checkpointing_p (ptid_get_pid (lp
->ptid
)))
1926 /* Handle checkpointing by linux-fork.c here as a special
1927 case. We don't want the follow-fork-mode or 'catch fork'
1928 to interfere with this. */
1930 /* This won't actually modify the breakpoint list, but will
1931 physically remove the breakpoints from the child. */
1932 detach_breakpoints (ptid_build (new_pid
, new_pid
, 0));
1934 /* Retain child fork in ptrace (stopped) state. */
1935 if (!find_fork_pid (new_pid
))
1938 /* Report as spurious, so that infrun doesn't want to follow
1939 this fork. We're actually doing an infcall in
1941 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
1943 /* Report the stop to the core. */
1947 if (event
== PTRACE_EVENT_FORK
)
1948 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
1949 else if (event
== PTRACE_EVENT_VFORK
)
1950 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
1953 struct lwp_info
*new_lp
;
1955 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
1957 if (debug_linux_nat
)
1958 fprintf_unfiltered (gdb_stdlog
,
1959 "LHEW: Got clone event "
1960 "from LWP %d, new child is LWP %ld\n",
1963 new_lp
= add_lwp (ptid_build (ptid_get_pid (lp
->ptid
), new_pid
, 0));
1965 new_lp
->stopped
= 1;
1967 if (WSTOPSIG (status
) != SIGSTOP
)
1969 /* This can happen if someone starts sending signals to
1970 the new thread before it gets a chance to run, which
1971 have a lower number than SIGSTOP (e.g. SIGUSR1).
1972 This is an unlikely case, and harder to handle for
1973 fork / vfork than for clone, so we do not try - but
1974 we handle it for clone events here. We'll send
1975 the other signal on to the thread below. */
1977 new_lp
->signalled
= 1;
1981 struct thread_info
*tp
;
1983 /* When we stop for an event in some other thread, and
1984 pull the thread list just as this thread has cloned,
1985 we'll have seen the new thread in the thread_db list
1986 before handling the CLONE event (glibc's
1987 pthread_create adds the new thread to the thread list
1988 before clone'ing, and has the kernel fill in the
1989 thread's tid on the clone call with
1990 CLONE_PARENT_SETTID). If that happened, and the core
1991 had requested the new thread to stop, we'll have
1992 killed it with SIGSTOP. But since SIGSTOP is not an
1993 RT signal, it can only be queued once. We need to be
1994 careful to not resume the LWP if we wanted it to
1995 stop. In that case, we'll leave the SIGSTOP pending.
1996 It will later be reported as GDB_SIGNAL_0. */
1997 tp
= find_thread_ptid (new_lp
->ptid
);
1998 if (tp
!= NULL
&& tp
->stop_requested
)
1999 new_lp
->last_resume_kind
= resume_stop
;
2006 /* Add the new thread to GDB's lists as soon as possible
2009 1) the frontend doesn't have to wait for a stop to
2012 2) we tag it with the correct running state. */
2014 /* If the thread_db layer is active, let it know about
2015 this new thread, and add it to GDB's list. */
2016 if (!thread_db_attach_lwp (new_lp
->ptid
))
2018 /* We're not using thread_db. Add it to GDB's
2020 target_post_attach (ptid_get_lwp (new_lp
->ptid
));
2021 add_thread (new_lp
->ptid
);
2026 set_running (new_lp
->ptid
, 1);
2027 set_executing (new_lp
->ptid
, 1);
2028 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2030 new_lp
->last_resume_kind
= resume_continue
;
2036 /* We created NEW_LP so it cannot yet contain STATUS. */
2037 gdb_assert (new_lp
->status
== 0);
2039 /* Save the wait status to report later. */
2040 if (debug_linux_nat
)
2041 fprintf_unfiltered (gdb_stdlog
,
2042 "LHEW: waitpid of new LWP %ld, "
2043 "saving status %s\n",
2044 (long) ptid_get_lwp (new_lp
->ptid
),
2045 status_to_str (status
));
2046 new_lp
->status
= status
;
2049 /* Note the need to use the low target ops to resume, to
2050 handle resuming with PT_SYSCALL if we have syscall
2054 new_lp
->resumed
= 1;
2058 gdb_assert (new_lp
->last_resume_kind
== resume_continue
);
2059 if (debug_linux_nat
)
2060 fprintf_unfiltered (gdb_stdlog
,
2061 "LHEW: resuming new LWP %ld\n",
2062 ptid_get_lwp (new_lp
->ptid
));
2063 linux_resume_one_lwp (new_lp
, 0, GDB_SIGNAL_0
);
2067 if (debug_linux_nat
)
2068 fprintf_unfiltered (gdb_stdlog
,
2069 "LHEW: resuming parent LWP %d\n", pid
);
2070 linux_resume_one_lwp (lp
, 0, GDB_SIGNAL_0
);
2077 if (event
== PTRACE_EVENT_EXEC
)
2079 if (debug_linux_nat
)
2080 fprintf_unfiltered (gdb_stdlog
,
2081 "LHEW: Got exec event from LWP %ld\n",
2082 ptid_get_lwp (lp
->ptid
));
2084 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2085 ourstatus
->value
.execd_pathname
2086 = xstrdup (linux_child_pid_to_exec_file (NULL
, pid
));
2091 if (event
== PTRACE_EVENT_VFORK_DONE
)
2093 if (current_inferior ()->waiting_for_vfork_done
)
2095 if (debug_linux_nat
)
2096 fprintf_unfiltered (gdb_stdlog
,
2097 "LHEW: Got expected PTRACE_EVENT_"
2098 "VFORK_DONE from LWP %ld: stopping\n",
2099 ptid_get_lwp (lp
->ptid
));
2101 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2105 if (debug_linux_nat
)
2106 fprintf_unfiltered (gdb_stdlog
,
2107 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2108 "from LWP %ld: resuming\n",
2109 ptid_get_lwp (lp
->ptid
));
2110 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2114 internal_error (__FILE__
, __LINE__
,
2115 _("unknown ptrace event %d"), event
);
2118 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2122 wait_lwp (struct lwp_info
*lp
)
2126 int thread_dead
= 0;
2129 gdb_assert (!lp
->stopped
);
2130 gdb_assert (lp
->status
== 0);
2132 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2133 block_child_signals (&prev_mask
);
2137 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2138 was right and we should just call sigsuspend. */
2140 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, WNOHANG
);
2141 if (pid
== -1 && errno
== ECHILD
)
2142 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, __WCLONE
| WNOHANG
);
2143 if (pid
== -1 && errno
== ECHILD
)
2145 /* The thread has previously exited. We need to delete it
2146 now because, for some vendor 2.4 kernels with NPTL
2147 support backported, there won't be an exit event unless
2148 it is the main thread. 2.6 kernels will report an exit
2149 event for each thread that exits, as expected. */
2151 if (debug_linux_nat
)
2152 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2153 target_pid_to_str (lp
->ptid
));
2158 /* Bugs 10970, 12702.
2159 Thread group leader may have exited in which case we'll lock up in
2160 waitpid if there are other threads, even if they are all zombies too.
2161 Basically, we're not supposed to use waitpid this way.
2162 __WCLONE is not applicable for the leader so we can't use that.
2163 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2164 process; it gets ESRCH both for the zombie and for running processes.
2166 As a workaround, check if we're waiting for the thread group leader and
2167 if it's a zombie, and avoid calling waitpid if it is.
2169 This is racy, what if the tgl becomes a zombie right after we check?
2170 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2171 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2173 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
)
2174 && linux_proc_pid_is_zombie (ptid_get_lwp (lp
->ptid
)))
2177 if (debug_linux_nat
)
2178 fprintf_unfiltered (gdb_stdlog
,
2179 "WL: Thread group leader %s vanished.\n",
2180 target_pid_to_str (lp
->ptid
));
2184 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2185 get invoked despite our caller had them intentionally blocked by
2186 block_child_signals. This is sensitive only to the loop of
2187 linux_nat_wait_1 and there if we get called my_waitpid gets called
2188 again before it gets to sigsuspend so we can safely let the handlers
2189 get executed here. */
2191 if (debug_linux_nat
)
2192 fprintf_unfiltered (gdb_stdlog
, "WL: about to sigsuspend\n");
2193 sigsuspend (&suspend_mask
);
2196 restore_child_signals_mask (&prev_mask
);
2200 gdb_assert (pid
== ptid_get_lwp (lp
->ptid
));
2202 if (debug_linux_nat
)
2204 fprintf_unfiltered (gdb_stdlog
,
2205 "WL: waitpid %s received %s\n",
2206 target_pid_to_str (lp
->ptid
),
2207 status_to_str (status
));
2210 /* Check if the thread has exited. */
2211 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2214 if (debug_linux_nat
)
2215 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2216 target_pid_to_str (lp
->ptid
));
2226 gdb_assert (WIFSTOPPED (status
));
2229 if (lp
->must_set_ptrace_flags
)
2231 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2233 linux_enable_event_reporting (ptid_get_lwp (lp
->ptid
), inf
->attach_flag
);
2234 lp
->must_set_ptrace_flags
= 0;
2237 /* Handle GNU/Linux's syscall SIGTRAPs. */
2238 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2240 /* No longer need the sysgood bit. The ptrace event ends up
2241 recorded in lp->waitstatus if we care for it. We can carry
2242 on handling the event like a regular SIGTRAP from here
2244 status
= W_STOPCODE (SIGTRAP
);
2245 if (linux_handle_syscall_trap (lp
, 1))
2246 return wait_lwp (lp
);
2249 /* Handle GNU/Linux's extended waitstatus for trace events. */
2250 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2251 && linux_is_extended_waitstatus (status
))
2253 if (debug_linux_nat
)
2254 fprintf_unfiltered (gdb_stdlog
,
2255 "WL: Handling extended status 0x%06x\n",
2257 if (linux_handle_extended_wait (lp
, status
, 1))
2258 return wait_lwp (lp
);
2264 /* Send a SIGSTOP to LP. */
2267 stop_callback (struct lwp_info
*lp
, void *data
)
2269 if (!lp
->stopped
&& !lp
->signalled
)
2273 if (debug_linux_nat
)
2275 fprintf_unfiltered (gdb_stdlog
,
2276 "SC: kill %s **<SIGSTOP>**\n",
2277 target_pid_to_str (lp
->ptid
));
2280 ret
= kill_lwp (ptid_get_lwp (lp
->ptid
), SIGSTOP
);
2281 if (debug_linux_nat
)
2283 fprintf_unfiltered (gdb_stdlog
,
2284 "SC: lwp kill %d %s\n",
2286 errno
? safe_strerror (errno
) : "ERRNO-OK");
2290 gdb_assert (lp
->status
== 0);
2296 /* Request a stop on LWP. */
2299 linux_stop_lwp (struct lwp_info
*lwp
)
2301 stop_callback (lwp
, NULL
);
2304 /* Return non-zero if LWP PID has a pending SIGINT. */
2307 linux_nat_has_pending_sigint (int pid
)
2309 sigset_t pending
, blocked
, ignored
;
2311 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2313 if (sigismember (&pending
, SIGINT
)
2314 && !sigismember (&ignored
, SIGINT
))
2320 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2323 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2325 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2326 flag to consume the next one. */
2327 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2328 && WSTOPSIG (lp
->status
) == SIGINT
)
2331 lp
->ignore_sigint
= 1;
2336 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2337 This function is called after we know the LWP has stopped; if the LWP
2338 stopped before the expected SIGINT was delivered, then it will never have
2339 arrived. Also, if the signal was delivered to a shared queue and consumed
2340 by a different thread, it will never be delivered to this LWP. */
2343 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2345 if (!lp
->ignore_sigint
)
2348 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp
->ptid
)))
2350 if (debug_linux_nat
)
2351 fprintf_unfiltered (gdb_stdlog
,
2352 "MCIS: Clearing bogus flag for %s\n",
2353 target_pid_to_str (lp
->ptid
));
2354 lp
->ignore_sigint
= 0;
2358 /* Fetch the possible triggered data watchpoint info and store it in
2361 On some archs, like x86, that use debug registers to set
2362 watchpoints, it's possible that the way to know which watched
2363 address trapped, is to check the register that is used to select
2364 which address to watch. Problem is, between setting the watchpoint
2365 and reading back which data address trapped, the user may change
2366 the set of watchpoints, and, as a consequence, GDB changes the
2367 debug registers in the inferior. To avoid reading back a stale
2368 stopped-data-address when that happens, we cache in LP the fact
2369 that a watchpoint trapped, and the corresponding data address, as
2370 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2371 registers meanwhile, we have the cached data we can rely on. */
2374 save_sigtrap (struct lwp_info
*lp
)
2376 struct cleanup
*old_chain
;
2378 if (linux_ops
->to_stopped_by_watchpoint
== NULL
)
2380 lp
->stopped_by_watchpoint
= 0;
2384 old_chain
= save_inferior_ptid ();
2385 inferior_ptid
= lp
->ptid
;
2387 lp
->stopped_by_watchpoint
= linux_ops
->to_stopped_by_watchpoint (linux_ops
);
2389 if (lp
->stopped_by_watchpoint
)
2391 if (linux_ops
->to_stopped_data_address
!= NULL
)
2392 lp
->stopped_data_address_p
=
2393 linux_ops
->to_stopped_data_address (¤t_target
,
2394 &lp
->stopped_data_address
);
2396 lp
->stopped_data_address_p
= 0;
2399 do_cleanups (old_chain
);
2402 /* See save_sigtrap. */
2405 linux_nat_stopped_by_watchpoint (struct target_ops
*ops
)
2407 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2409 gdb_assert (lp
!= NULL
);
2411 return lp
->stopped_by_watchpoint
;
2415 linux_nat_stopped_data_address (struct target_ops
*ops
, CORE_ADDR
*addr_p
)
2417 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2419 gdb_assert (lp
!= NULL
);
2421 *addr_p
= lp
->stopped_data_address
;
2423 return lp
->stopped_data_address_p
;
2426 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2429 sigtrap_is_event (int status
)
2431 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2434 /* SIGTRAP-like events recognizer. */
2436 static int (*linux_nat_status_is_event
) (int status
) = sigtrap_is_event
;
2438 /* Check for SIGTRAP-like events in LP. */
2441 linux_nat_lp_status_is_event (struct lwp_info
*lp
)
2443 /* We check for lp->waitstatus in addition to lp->status, because we can
2444 have pending process exits recorded in lp->status
2445 and W_EXITCODE(0,0) == 0. We should probably have an additional
2446 lp->status_p flag. */
2448 return (lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
2449 && linux_nat_status_is_event (lp
->status
));
2452 /* Set alternative SIGTRAP-like events recognizer. If
2453 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2457 linux_nat_set_status_is_event (struct target_ops
*t
,
2458 int (*status_is_event
) (int status
))
2460 linux_nat_status_is_event
= status_is_event
;
2463 /* Wait until LP is stopped. */
2466 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2468 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
2470 /* If this is a vfork parent, bail out, it is not going to report
2471 any SIGSTOP until the vfork is done with. */
2472 if (inf
->vfork_child
!= NULL
)
2479 status
= wait_lwp (lp
);
2483 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2484 && WSTOPSIG (status
) == SIGINT
)
2486 lp
->ignore_sigint
= 0;
2489 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2491 if (debug_linux_nat
)
2492 fprintf_unfiltered (gdb_stdlog
,
2493 "PTRACE_CONT %s, 0, 0 (%s) "
2494 "(discarding SIGINT)\n",
2495 target_pid_to_str (lp
->ptid
),
2496 errno
? safe_strerror (errno
) : "OK");
2498 return stop_wait_callback (lp
, NULL
);
2501 maybe_clear_ignore_sigint (lp
);
2503 if (WSTOPSIG (status
) != SIGSTOP
)
2505 /* The thread was stopped with a signal other than SIGSTOP. */
2509 if (debug_linux_nat
)
2510 fprintf_unfiltered (gdb_stdlog
,
2511 "SWC: Pending event %s in %s\n",
2512 status_to_str ((int) status
),
2513 target_pid_to_str (lp
->ptid
));
2515 /* Save the sigtrap event. */
2516 lp
->status
= status
;
2517 gdb_assert (lp
->signalled
);
2521 /* We caught the SIGSTOP that we intended to catch, so
2522 there's no SIGSTOP pending. */
2524 if (debug_linux_nat
)
2525 fprintf_unfiltered (gdb_stdlog
,
2526 "SWC: Delayed SIGSTOP caught for %s.\n",
2527 target_pid_to_str (lp
->ptid
));
2529 /* Reset SIGNALLED only after the stop_wait_callback call
2530 above as it does gdb_assert on SIGNALLED. */
2538 /* Return non-zero if LP has a wait status pending. */
2541 status_callback (struct lwp_info
*lp
, void *data
)
2543 /* Only report a pending wait status if we pretend that this has
2544 indeed been resumed. */
2548 return lwp_status_pending_p (lp
);
2551 /* Return non-zero if LP isn't stopped. */
2554 running_callback (struct lwp_info
*lp
, void *data
)
2556 return (!lp
->stopped
2557 || (lwp_status_pending_p (lp
) && lp
->resumed
));
2560 /* Count the LWP's that have had events. */
2563 count_events_callback (struct lwp_info
*lp
, void *data
)
2567 gdb_assert (count
!= NULL
);
2569 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2570 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2576 /* Select the LWP (if any) that is currently being single-stepped. */
2579 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2581 if (lp
->last_resume_kind
== resume_step
2588 /* Returns true if LP has a status pending. */
2591 lwp_status_pending_p (struct lwp_info
*lp
)
2593 /* We check for lp->waitstatus in addition to lp->status, because we
2594 can have pending process exits recorded in lp->status and
2595 W_EXITCODE(0,0) happens to be 0. */
2596 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2599 /* Select the Nth LWP that has had a SIGTRAP event. */
2602 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2604 int *selector
= data
;
2606 gdb_assert (selector
!= NULL
);
2608 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2609 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2610 if ((*selector
)-- == 0)
2617 cancel_breakpoint (struct lwp_info
*lp
)
2619 /* Arrange for a breakpoint to be hit again later. We don't keep
2620 the SIGTRAP status and don't forward the SIGTRAP signal to the
2621 LWP. We will handle the current event, eventually we will resume
2622 this LWP, and this breakpoint will trap again.
2624 If we do not do this, then we run the risk that the user will
2625 delete or disable the breakpoint, but the LWP will have already
2628 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2629 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2632 pc
= regcache_read_pc (regcache
) - target_decr_pc_after_break (gdbarch
);
2633 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2635 if (debug_linux_nat
)
2636 fprintf_unfiltered (gdb_stdlog
,
2637 "CB: Push back breakpoint for %s\n",
2638 target_pid_to_str (lp
->ptid
));
2640 /* Back up the PC if necessary. */
2641 if (target_decr_pc_after_break (gdbarch
))
2642 regcache_write_pc (regcache
, pc
);
2650 cancel_breakpoints_callback (struct lwp_info
*lp
, void *data
)
2652 struct lwp_info
*event_lp
= data
;
2654 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2658 /* If a LWP other than the LWP that we're reporting an event for has
2659 hit a GDB breakpoint (as opposed to some random trap signal),
2660 then just arrange for it to hit it again later. We don't keep
2661 the SIGTRAP status and don't forward the SIGTRAP signal to the
2662 LWP. We will handle the current event, eventually we will resume
2663 all LWPs, and this one will get its breakpoint trap again.
2665 If we do not do this, then we run the risk that the user will
2666 delete or disable the breakpoint, but the LWP will have already
2669 if (linux_nat_lp_status_is_event (lp
)
2670 && cancel_breakpoint (lp
))
2671 /* Throw away the SIGTRAP. */
2677 /* Select one LWP out of those that have events pending. */
2680 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2683 int random_selector
;
2684 struct lwp_info
*event_lp
;
2686 /* Record the wait status for the original LWP. */
2687 (*orig_lp
)->status
= *status
;
2689 /* Give preference to any LWP that is being single-stepped. */
2690 event_lp
= iterate_over_lwps (filter
,
2691 select_singlestep_lwp_callback
, NULL
);
2692 if (event_lp
!= NULL
)
2694 if (debug_linux_nat
)
2695 fprintf_unfiltered (gdb_stdlog
,
2696 "SEL: Select single-step %s\n",
2697 target_pid_to_str (event_lp
->ptid
));
2701 /* No single-stepping LWP. Select one at random, out of those
2702 which have had SIGTRAP events. */
2704 /* First see how many SIGTRAP events we have. */
2705 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2707 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2708 random_selector
= (int)
2709 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2711 if (debug_linux_nat
&& num_events
> 1)
2712 fprintf_unfiltered (gdb_stdlog
,
2713 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2714 num_events
, random_selector
);
2716 event_lp
= iterate_over_lwps (filter
,
2717 select_event_lwp_callback
,
2721 if (event_lp
!= NULL
)
2723 /* Switch the event LWP. */
2724 *orig_lp
= event_lp
;
2725 *status
= event_lp
->status
;
2728 /* Flush the wait status for the event LWP. */
2729 (*orig_lp
)->status
= 0;
2732 /* Return non-zero if LP has been resumed. */
2735 resumed_callback (struct lwp_info
*lp
, void *data
)
2740 /* Stop an active thread, verify it still exists, then resume it. If
2741 the thread ends up with a pending status, then it is not resumed,
2742 and *DATA (really a pointer to int), is set. */
2745 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2747 int *new_pending_p
= data
;
2751 ptid_t ptid
= lp
->ptid
;
2753 stop_callback (lp
, NULL
);
2754 stop_wait_callback (lp
, NULL
);
2756 /* Resume if the lwp still exists, and the core wanted it
2758 lp
= find_lwp_pid (ptid
);
2761 if (lp
->last_resume_kind
== resume_stop
2762 && !lwp_status_pending_p (lp
))
2764 /* The core wanted the LWP to stop. Even if it stopped
2765 cleanly (with SIGSTOP), leave the event pending. */
2766 if (debug_linux_nat
)
2767 fprintf_unfiltered (gdb_stdlog
,
2768 "SARC: core wanted LWP %ld stopped "
2769 "(leaving SIGSTOP pending)\n",
2770 ptid_get_lwp (lp
->ptid
));
2771 lp
->status
= W_STOPCODE (SIGSTOP
);
2774 if (!lwp_status_pending_p (lp
))
2776 if (debug_linux_nat
)
2777 fprintf_unfiltered (gdb_stdlog
,
2778 "SARC: re-resuming LWP %ld\n",
2779 ptid_get_lwp (lp
->ptid
));
2780 resume_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2784 if (debug_linux_nat
)
2785 fprintf_unfiltered (gdb_stdlog
,
2786 "SARC: not re-resuming LWP %ld "
2788 ptid_get_lwp (lp
->ptid
));
2797 /* Check if we should go on and pass this event to common code.
2798 Return the affected lwp if we are, or NULL otherwise. If we stop
2799 all lwps temporarily, we may end up with new pending events in some
2800 other lwp. In that case set *NEW_PENDING_P to true. */
2802 static struct lwp_info
*
2803 linux_nat_filter_event (int lwpid
, int status
, int *new_pending_p
)
2805 struct lwp_info
*lp
;
2806 int event
= linux_ptrace_get_extended_event (status
);
2810 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2812 /* Check for stop events reported by a process we didn't already
2813 know about - anything not already in our LWP list.
2815 If we're expecting to receive stopped processes after
2816 fork, vfork, and clone events, then we'll just add the
2817 new one to our list and go back to waiting for the event
2818 to be reported - the stopped process might be returned
2819 from waitpid before or after the event is.
2821 But note the case of a non-leader thread exec'ing after the
2822 leader having exited, and gone from our lists. The non-leader
2823 thread changes its tid to the tgid. */
2825 if (WIFSTOPPED (status
) && lp
== NULL
2826 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2828 /* A multi-thread exec after we had seen the leader exiting. */
2829 if (debug_linux_nat
)
2830 fprintf_unfiltered (gdb_stdlog
,
2831 "LLW: Re-adding thread group leader LWP %d.\n",
2834 lp
= add_lwp (ptid_build (lwpid
, lwpid
, 0));
2837 add_thread (lp
->ptid
);
2840 if (WIFSTOPPED (status
) && !lp
)
2842 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2846 /* Make sure we don't report an event for the exit of an LWP not in
2847 our list, i.e. not part of the current process. This can happen
2848 if we detach from a program we originally forked and then it
2850 if (!WIFSTOPPED (status
) && !lp
)
2853 /* This LWP is stopped now. (And if dead, this prevents it from
2854 ever being continued.) */
2857 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2859 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2861 linux_enable_event_reporting (ptid_get_lwp (lp
->ptid
), inf
->attach_flag
);
2862 lp
->must_set_ptrace_flags
= 0;
2865 /* Handle GNU/Linux's syscall SIGTRAPs. */
2866 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2868 /* No longer need the sysgood bit. The ptrace event ends up
2869 recorded in lp->waitstatus if we care for it. We can carry
2870 on handling the event like a regular SIGTRAP from here
2872 status
= W_STOPCODE (SIGTRAP
);
2873 if (linux_handle_syscall_trap (lp
, 0))
2877 /* Handle GNU/Linux's extended waitstatus for trace events. */
2878 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2879 && linux_is_extended_waitstatus (status
))
2881 if (debug_linux_nat
)
2882 fprintf_unfiltered (gdb_stdlog
,
2883 "LLW: Handling extended status 0x%06x\n",
2885 if (linux_handle_extended_wait (lp
, status
, 0))
2889 if (linux_nat_status_is_event (status
))
2892 /* Check if the thread has exited. */
2893 if ((WIFEXITED (status
) || WIFSIGNALED (status
))
2894 && num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2896 /* If this is the main thread, we must stop all threads and verify
2897 if they are still alive. This is because in the nptl thread model
2898 on Linux 2.4, there is no signal issued for exiting LWPs
2899 other than the main thread. We only get the main thread exit
2900 signal once all child threads have already exited. If we
2901 stop all the threads and use the stop_wait_callback to check
2902 if they have exited we can determine whether this signal
2903 should be ignored or whether it means the end of the debugged
2904 application, regardless of which threading model is being
2906 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
))
2908 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
2909 stop_and_resume_callback
, new_pending_p
);
2912 if (debug_linux_nat
)
2913 fprintf_unfiltered (gdb_stdlog
,
2914 "LLW: %s exited.\n",
2915 target_pid_to_str (lp
->ptid
));
2917 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2919 /* If there is at least one more LWP, then the exit signal
2920 was not the end of the debugged application and should be
2927 /* Check if the current LWP has previously exited. In the nptl
2928 thread model, LWPs other than the main thread do not issue
2929 signals when they exit so we must check whenever the thread has
2930 stopped. A similar check is made in stop_wait_callback(). */
2931 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1 && !linux_thread_alive (lp
->ptid
))
2933 ptid_t ptid
= pid_to_ptid (ptid_get_pid (lp
->ptid
));
2935 if (debug_linux_nat
)
2936 fprintf_unfiltered (gdb_stdlog
,
2937 "LLW: %s exited.\n",
2938 target_pid_to_str (lp
->ptid
));
2942 /* Make sure there is at least one thread running. */
2943 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
2945 /* Discard the event. */
2949 /* Make sure we don't report a SIGSTOP that we sent ourselves in
2950 an attempt to stop an LWP. */
2952 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
2954 if (debug_linux_nat
)
2955 fprintf_unfiltered (gdb_stdlog
,
2956 "LLW: Delayed SIGSTOP caught for %s.\n",
2957 target_pid_to_str (lp
->ptid
));
2961 if (lp
->last_resume_kind
!= resume_stop
)
2963 /* This is a delayed SIGSTOP. */
2965 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2966 if (debug_linux_nat
)
2967 fprintf_unfiltered (gdb_stdlog
,
2968 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
2970 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2971 target_pid_to_str (lp
->ptid
));
2973 gdb_assert (lp
->resumed
);
2975 /* Discard the event. */
2980 /* Make sure we don't report a SIGINT that we have already displayed
2981 for another thread. */
2982 if (lp
->ignore_sigint
2983 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
2985 if (debug_linux_nat
)
2986 fprintf_unfiltered (gdb_stdlog
,
2987 "LLW: Delayed SIGINT caught for %s.\n",
2988 target_pid_to_str (lp
->ptid
));
2990 /* This is a delayed SIGINT. */
2991 lp
->ignore_sigint
= 0;
2993 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2994 if (debug_linux_nat
)
2995 fprintf_unfiltered (gdb_stdlog
,
2996 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
2998 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2999 target_pid_to_str (lp
->ptid
));
3000 gdb_assert (lp
->resumed
);
3002 /* Discard the event. */
3006 /* An interesting event. */
3008 lp
->status
= status
;
3012 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3013 their exits until all other threads in the group have exited. */
3016 check_zombie_leaders (void)
3018 struct inferior
*inf
;
3022 struct lwp_info
*leader_lp
;
3027 leader_lp
= find_lwp_pid (pid_to_ptid (inf
->pid
));
3028 if (leader_lp
!= NULL
3029 /* Check if there are other threads in the group, as we may
3030 have raced with the inferior simply exiting. */
3031 && num_lwps (inf
->pid
) > 1
3032 && linux_proc_pid_is_zombie (inf
->pid
))
3034 if (debug_linux_nat
)
3035 fprintf_unfiltered (gdb_stdlog
,
3036 "CZL: Thread group leader %d zombie "
3037 "(it exited, or another thread execd).\n",
3040 /* A leader zombie can mean one of two things:
3042 - It exited, and there's an exit status pending
3043 available, or only the leader exited (not the whole
3044 program). In the latter case, we can't waitpid the
3045 leader's exit status until all other threads are gone.
3047 - There are 3 or more threads in the group, and a thread
3048 other than the leader exec'd. On an exec, the Linux
3049 kernel destroys all other threads (except the execing
3050 one) in the thread group, and resets the execing thread's
3051 tid to the tgid. No exit notification is sent for the
3052 execing thread -- from the ptracer's perspective, it
3053 appears as though the execing thread just vanishes.
3054 Until we reap all other threads except the leader and the
3055 execing thread, the leader will be zombie, and the
3056 execing thread will be in `D (disc sleep)'. As soon as
3057 all other threads are reaped, the execing thread changes
3058 it's tid to the tgid, and the previous (zombie) leader
3059 vanishes, giving place to the "new" leader. We could try
3060 distinguishing the exit and exec cases, by waiting once
3061 more, and seeing if something comes out, but it doesn't
3062 sound useful. The previous leader _does_ go away, and
3063 we'll re-add the new one once we see the exec event
3064 (which is just the same as what would happen if the
3065 previous leader did exit voluntarily before some other
3068 if (debug_linux_nat
)
3069 fprintf_unfiltered (gdb_stdlog
,
3070 "CZL: Thread group leader %d vanished.\n",
3072 exit_lwp (leader_lp
);
3078 linux_nat_wait_1 (struct target_ops
*ops
,
3079 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3083 enum resume_kind last_resume_kind
;
3084 struct lwp_info
*lp
;
3087 if (debug_linux_nat
)
3088 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3090 /* The first time we get here after starting a new inferior, we may
3091 not have added it to the LWP list yet - this is the earliest
3092 moment at which we know its PID. */
3093 if (ptid_is_pid (inferior_ptid
))
3095 /* Upgrade the main thread's ptid. */
3096 thread_change_ptid (inferior_ptid
,
3097 ptid_build (ptid_get_pid (inferior_ptid
),
3098 ptid_get_pid (inferior_ptid
), 0));
3100 lp
= add_initial_lwp (inferior_ptid
);
3104 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3105 block_child_signals (&prev_mask
);
3110 /* First check if there is a LWP with a wait status pending. */
3111 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3114 if (debug_linux_nat
)
3115 fprintf_unfiltered (gdb_stdlog
,
3116 "LLW: Using pending wait status %s for %s.\n",
3117 status_to_str (lp
->status
),
3118 target_pid_to_str (lp
->ptid
));
3121 if (!target_can_async_p ())
3123 /* Causes SIGINT to be passed on to the attached process. */
3127 /* But if we don't find a pending event, we'll have to wait. */
3133 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3136 - If the thread group leader exits while other threads in the
3137 thread group still exist, waitpid(TGID, ...) hangs. That
3138 waitpid won't return an exit status until the other threads
3139 in the group are reapped.
3141 - When a non-leader thread execs, that thread just vanishes
3142 without reporting an exit (so we'd hang if we waited for it
3143 explicitly in that case). The exec event is reported to
3147 lwpid
= my_waitpid (-1, &status
, __WCLONE
| WNOHANG
);
3148 if (lwpid
== 0 || (lwpid
== -1 && errno
== ECHILD
))
3149 lwpid
= my_waitpid (-1, &status
, WNOHANG
);
3151 if (debug_linux_nat
)
3152 fprintf_unfiltered (gdb_stdlog
,
3153 "LNW: waitpid(-1, ...) returned %d, %s\n",
3154 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3158 /* If this is true, then we paused LWPs momentarily, and may
3159 now have pending events to handle. */
3162 if (debug_linux_nat
)
3164 fprintf_unfiltered (gdb_stdlog
,
3165 "LLW: waitpid %ld received %s\n",
3166 (long) lwpid
, status_to_str (status
));
3169 lp
= linux_nat_filter_event (lwpid
, status
, &new_pending
);
3171 /* STATUS is now no longer valid, use LP->STATUS instead. */
3174 if (lp
&& !ptid_match (lp
->ptid
, ptid
))
3176 gdb_assert (lp
->resumed
);
3178 if (debug_linux_nat
)
3179 fprintf_unfiltered (gdb_stdlog
,
3180 "LWP %ld got an event %06x, "
3181 "leaving pending.\n",
3182 ptid_get_lwp (lp
->ptid
), lp
->status
);
3184 if (WIFSTOPPED (lp
->status
))
3186 if (WSTOPSIG (lp
->status
) != SIGSTOP
)
3188 /* Cancel breakpoint hits. The breakpoint may
3189 be removed before we fetch events from this
3190 process to report to the core. It is best
3191 not to assume the moribund breakpoints
3192 heuristic always handles these cases --- it
3193 could be too many events go through to the
3194 core before this one is handled. All-stop
3195 always cancels breakpoint hits in all
3198 && linux_nat_lp_status_is_event (lp
)
3199 && cancel_breakpoint (lp
))
3201 /* Throw away the SIGTRAP. */
3204 if (debug_linux_nat
)
3205 fprintf_unfiltered (gdb_stdlog
,
3206 "LLW: LWP %ld hit a "
3208 "waiting for another "
3211 ptid_get_lwp (lp
->ptid
));
3217 else if (WIFEXITED (lp
->status
) || WIFSIGNALED (lp
->status
))
3219 if (debug_linux_nat
)
3220 fprintf_unfiltered (gdb_stdlog
,
3221 "Process %ld exited while stopping "
3223 ptid_get_lwp (lp
->ptid
));
3225 /* This was the last lwp in the process. Since
3226 events are serialized to GDB core, and we can't
3227 report this one right now, but GDB core and the
3228 other target layers will want to be notified
3229 about the exit code/signal, leave the status
3230 pending for the next time we're able to report
3233 /* Dead LWP's aren't expected to reported a pending
3237 /* Store the pending event in the waitstatus as
3238 well, because W_EXITCODE(0,0) == 0. */
3239 store_waitstatus (&lp
->waitstatus
, lp
->status
);
3248 /* Some LWP now has a pending event. Go all the way
3249 back to check it. */
3255 /* We got an event to report to the core. */
3259 /* Retry until nothing comes out of waitpid. A single
3260 SIGCHLD can indicate more than one child stopped. */
3264 /* Check for zombie thread group leaders. Those can't be reaped
3265 until all other threads in the thread group are. */
3266 check_zombie_leaders ();
3268 /* If there are no resumed children left, bail. We'd be stuck
3269 forever in the sigsuspend call below otherwise. */
3270 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3272 if (debug_linux_nat
)
3273 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3275 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3277 if (!target_can_async_p ())
3278 clear_sigint_trap ();
3280 restore_child_signals_mask (&prev_mask
);
3281 return minus_one_ptid
;
3284 /* No interesting event to report to the core. */
3286 if (target_options
& TARGET_WNOHANG
)
3288 if (debug_linux_nat
)
3289 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3291 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3292 restore_child_signals_mask (&prev_mask
);
3293 return minus_one_ptid
;
3296 /* We shouldn't end up here unless we want to try again. */
3297 gdb_assert (lp
== NULL
);
3299 /* Block until we get an event reported with SIGCHLD. */
3300 if (debug_linux_nat
)
3301 fprintf_unfiltered (gdb_stdlog
, "LNW: about to sigsuspend\n");
3302 sigsuspend (&suspend_mask
);
3305 if (!target_can_async_p ())
3306 clear_sigint_trap ();
3310 status
= lp
->status
;
3313 /* Don't report signals that GDB isn't interested in, such as
3314 signals that are neither printed nor stopped upon. Stopping all
3315 threads can be a bit time-consuming so if we want decent
3316 performance with heavily multi-threaded programs, especially when
3317 they're using a high frequency timer, we'd better avoid it if we
3320 if (WIFSTOPPED (status
))
3322 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3324 /* When using hardware single-step, we need to report every signal.
3325 Otherwise, signals in pass_mask may be short-circuited. */
3327 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
)))
3329 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3330 here? It is not clear we should. GDB may not expect
3331 other threads to run. On the other hand, not resuming
3332 newly attached threads may cause an unwanted delay in
3333 getting them running. */
3334 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3335 if (debug_linux_nat
)
3336 fprintf_unfiltered (gdb_stdlog
,
3337 "LLW: %s %s, %s (preempt 'handle')\n",
3339 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3340 target_pid_to_str (lp
->ptid
),
3341 (signo
!= GDB_SIGNAL_0
3342 ? strsignal (gdb_signal_to_host (signo
))
3349 /* Only do the below in all-stop, as we currently use SIGINT
3350 to implement target_stop (see linux_nat_stop) in
3352 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3354 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3355 forwarded to the entire process group, that is, all LWPs
3356 will receive it - unless they're using CLONE_THREAD to
3357 share signals. Since we only want to report it once, we
3358 mark it as ignored for all LWPs except this one. */
3359 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid
)),
3360 set_ignore_sigint
, NULL
);
3361 lp
->ignore_sigint
= 0;
3364 maybe_clear_ignore_sigint (lp
);
3368 /* This LWP is stopped now. */
3371 if (debug_linux_nat
)
3372 fprintf_unfiltered (gdb_stdlog
, "LLW: Candidate event %s in %s.\n",
3373 status_to_str (status
), target_pid_to_str (lp
->ptid
));
3377 /* Now stop all other LWP's ... */
3378 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3380 /* ... and wait until all of them have reported back that
3381 they're no longer running. */
3382 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3384 /* If we're not waiting for a specific LWP, choose an event LWP
3385 from among those that have had events. Giving equal priority
3386 to all LWPs that have had events helps prevent
3388 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3389 select_event_lwp (ptid
, &lp
, &status
);
3391 /* Now that we've selected our final event LWP, cancel any
3392 breakpoints in other LWPs that have hit a GDB breakpoint.
3393 See the comment in cancel_breakpoints_callback to find out
3395 iterate_over_lwps (minus_one_ptid
, cancel_breakpoints_callback
, lp
);
3397 /* We'll need this to determine whether to report a SIGSTOP as
3398 TARGET_WAITKIND_0. Need to take a copy because
3399 resume_clear_callback clears it. */
3400 last_resume_kind
= lp
->last_resume_kind
;
3402 /* In all-stop, from the core's perspective, all LWPs are now
3403 stopped until a new resume action is sent over. */
3404 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3409 last_resume_kind
= lp
->last_resume_kind
;
3410 resume_clear_callback (lp
, NULL
);
3413 if (linux_nat_status_is_event (status
))
3415 if (debug_linux_nat
)
3416 fprintf_unfiltered (gdb_stdlog
,
3417 "LLW: trap ptid is %s.\n",
3418 target_pid_to_str (lp
->ptid
));
3421 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3423 *ourstatus
= lp
->waitstatus
;
3424 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3427 store_waitstatus (ourstatus
, status
);
3429 if (debug_linux_nat
)
3430 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3432 restore_child_signals_mask (&prev_mask
);
3434 if (last_resume_kind
== resume_stop
3435 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3436 && WSTOPSIG (status
) == SIGSTOP
)
3438 /* A thread that has been requested to stop by GDB with
3439 target_stop, and it stopped cleanly, so report as SIG0. The
3440 use of SIGSTOP is an implementation detail. */
3441 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3444 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3445 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3448 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3453 /* Resume LWPs that are currently stopped without any pending status
3454 to report, but are resumed from the core's perspective. */
3457 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3459 ptid_t
*wait_ptid_p
= data
;
3463 && !lwp_status_pending_p (lp
))
3465 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3466 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3467 CORE_ADDR pc
= regcache_read_pc (regcache
);
3469 gdb_assert (is_executing (lp
->ptid
));
3471 /* Don't bother if there's a breakpoint at PC that we'd hit
3472 immediately, and we're not waiting for this LWP. */
3473 if (!ptid_match (lp
->ptid
, *wait_ptid_p
))
3475 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
3479 if (debug_linux_nat
)
3480 fprintf_unfiltered (gdb_stdlog
,
3481 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3482 target_pid_to_str (lp
->ptid
),
3483 paddress (gdbarch
, pc
),
3486 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3493 linux_nat_wait (struct target_ops
*ops
,
3494 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3499 if (debug_linux_nat
)
3501 char *options_string
;
3503 options_string
= target_options_to_string (target_options
);
3504 fprintf_unfiltered (gdb_stdlog
,
3505 "linux_nat_wait: [%s], [%s]\n",
3506 target_pid_to_str (ptid
),
3508 xfree (options_string
);
3511 /* Flush the async file first. */
3512 if (target_can_async_p ())
3513 async_file_flush ();
3515 /* Resume LWPs that are currently stopped without any pending status
3516 to report, but are resumed from the core's perspective. LWPs get
3517 in this state if we find them stopping at a time we're not
3518 interested in reporting the event (target_wait on a
3519 specific_process, for example, see linux_nat_wait_1), and
3520 meanwhile the event became uninteresting. Don't bother resuming
3521 LWPs we're not going to wait for if they'd stop immediately. */
3523 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3525 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
3527 /* If we requested any event, and something came out, assume there
3528 may be more. If we requested a specific lwp or process, also
3529 assume there may be more. */
3530 if (target_can_async_p ()
3531 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3532 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3533 || !ptid_equal (ptid
, minus_one_ptid
)))
3536 /* Get ready for the next event. */
3537 if (target_can_async_p ())
3538 target_async (inferior_event_handler
, 0);
3544 kill_callback (struct lwp_info
*lp
, void *data
)
3546 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3549 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGKILL
);
3550 if (debug_linux_nat
)
3552 int save_errno
= errno
;
3554 fprintf_unfiltered (gdb_stdlog
,
3555 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3556 target_pid_to_str (lp
->ptid
),
3557 save_errno
? safe_strerror (save_errno
) : "OK");
3560 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3563 ptrace (PTRACE_KILL
, ptid_get_lwp (lp
->ptid
), 0, 0);
3564 if (debug_linux_nat
)
3566 int save_errno
= errno
;
3568 fprintf_unfiltered (gdb_stdlog
,
3569 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3570 target_pid_to_str (lp
->ptid
),
3571 save_errno
? safe_strerror (save_errno
) : "OK");
3578 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3582 /* We must make sure that there are no pending events (delayed
3583 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3584 program doesn't interfere with any following debugging session. */
3586 /* For cloned processes we must check both with __WCLONE and
3587 without, since the exit status of a cloned process isn't reported
3593 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, __WCLONE
);
3594 if (pid
!= (pid_t
) -1)
3596 if (debug_linux_nat
)
3597 fprintf_unfiltered (gdb_stdlog
,
3598 "KWC: wait %s received unknown.\n",
3599 target_pid_to_str (lp
->ptid
));
3600 /* The Linux kernel sometimes fails to kill a thread
3601 completely after PTRACE_KILL; that goes from the stop
3602 point in do_fork out to the one in
3603 get_signal_to_deliever and waits again. So kill it
3605 kill_callback (lp
, NULL
);
3608 while (pid
== ptid_get_lwp (lp
->ptid
));
3610 gdb_assert (pid
== -1 && errno
== ECHILD
);
3615 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, 0);
3616 if (pid
!= (pid_t
) -1)
3618 if (debug_linux_nat
)
3619 fprintf_unfiltered (gdb_stdlog
,
3620 "KWC: wait %s received unk.\n",
3621 target_pid_to_str (lp
->ptid
));
3622 /* See the call to kill_callback above. */
3623 kill_callback (lp
, NULL
);
3626 while (pid
== ptid_get_lwp (lp
->ptid
));
3628 gdb_assert (pid
== -1 && errno
== ECHILD
);
3633 linux_nat_kill (struct target_ops
*ops
)
3635 struct target_waitstatus last
;
3639 /* If we're stopped while forking and we haven't followed yet,
3640 kill the other task. We need to do this first because the
3641 parent will be sleeping if this is a vfork. */
3643 get_last_target_status (&last_ptid
, &last
);
3645 if (last
.kind
== TARGET_WAITKIND_FORKED
3646 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3648 ptrace (PT_KILL
, ptid_get_pid (last
.value
.related_pid
), 0, 0);
3651 /* Let the arch-specific native code know this process is
3653 linux_nat_forget_process (ptid_get_pid (last
.value
.related_pid
));
3656 if (forks_exist_p ())
3657 linux_fork_killall ();
3660 ptid_t ptid
= pid_to_ptid (ptid_get_pid (inferior_ptid
));
3662 /* Stop all threads before killing them, since ptrace requires
3663 that the thread is stopped to sucessfully PTRACE_KILL. */
3664 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3665 /* ... and wait until all of them have reported back that
3666 they're no longer running. */
3667 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3669 /* Kill all LWP's ... */
3670 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3672 /* ... and wait until we've flushed all events. */
3673 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3676 target_mourn_inferior ();
3680 linux_nat_mourn_inferior (struct target_ops
*ops
)
3682 int pid
= ptid_get_pid (inferior_ptid
);
3684 purge_lwp_list (pid
);
3686 if (! forks_exist_p ())
3687 /* Normal case, no other forks available. */
3688 linux_ops
->to_mourn_inferior (ops
);
3690 /* Multi-fork case. The current inferior_ptid has exited, but
3691 there are other viable forks to debug. Delete the exiting
3692 one and context-switch to the first available. */
3693 linux_fork_mourn_inferior ();
3695 /* Let the arch-specific native code know this process is gone. */
3696 linux_nat_forget_process (pid
);
3699 /* Convert a native/host siginfo object, into/from the siginfo in the
3700 layout of the inferiors' architecture. */
3703 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3707 if (linux_nat_siginfo_fixup
!= NULL
)
3708 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3710 /* If there was no callback, or the callback didn't do anything,
3711 then just do a straight memcpy. */
3715 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3717 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3721 static enum target_xfer_status
3722 linux_xfer_siginfo (struct target_ops
*ops
, enum target_object object
,
3723 const char *annex
, gdb_byte
*readbuf
,
3724 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3725 ULONGEST
*xfered_len
)
3729 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3731 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3732 gdb_assert (readbuf
|| writebuf
);
3734 pid
= ptid_get_lwp (inferior_ptid
);
3736 pid
= ptid_get_pid (inferior_ptid
);
3738 if (offset
> sizeof (siginfo
))
3739 return TARGET_XFER_E_IO
;
3742 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3744 return TARGET_XFER_E_IO
;
3746 /* When GDB is built as a 64-bit application, ptrace writes into
3747 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3748 inferior with a 64-bit GDB should look the same as debugging it
3749 with a 32-bit GDB, we need to convert it. GDB core always sees
3750 the converted layout, so any read/write will have to be done
3752 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3754 if (offset
+ len
> sizeof (siginfo
))
3755 len
= sizeof (siginfo
) - offset
;
3757 if (readbuf
!= NULL
)
3758 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3761 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3763 /* Convert back to ptrace layout before flushing it out. */
3764 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3767 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3769 return TARGET_XFER_E_IO
;
3773 return TARGET_XFER_OK
;
3776 static enum target_xfer_status
3777 linux_nat_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3778 const char *annex
, gdb_byte
*readbuf
,
3779 const gdb_byte
*writebuf
,
3780 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3782 struct cleanup
*old_chain
;
3783 enum target_xfer_status xfer
;
3785 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3786 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3787 offset
, len
, xfered_len
);
3789 /* The target is connected but no live inferior is selected. Pass
3790 this request down to a lower stratum (e.g., the executable
3792 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3793 return TARGET_XFER_EOF
;
3795 old_chain
= save_inferior_ptid ();
3797 if (ptid_lwp_p (inferior_ptid
))
3798 inferior_ptid
= pid_to_ptid (ptid_get_lwp (inferior_ptid
));
3800 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3801 offset
, len
, xfered_len
);
3803 do_cleanups (old_chain
);
3808 linux_thread_alive (ptid_t ptid
)
3812 gdb_assert (ptid_lwp_p (ptid
));
3814 /* Send signal 0 instead of anything ptrace, because ptracing a
3815 running thread errors out claiming that the thread doesn't
3817 err
= kill_lwp (ptid_get_lwp (ptid
), 0);
3819 if (debug_linux_nat
)
3820 fprintf_unfiltered (gdb_stdlog
,
3821 "LLTA: KILL(SIG0) %s (%s)\n",
3822 target_pid_to_str (ptid
),
3823 err
? safe_strerror (tmp_errno
) : "OK");
3832 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3834 return linux_thread_alive (ptid
);
3838 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3840 static char buf
[64];
3842 if (ptid_lwp_p (ptid
)
3843 && (ptid_get_pid (ptid
) != ptid_get_lwp (ptid
)
3844 || num_lwps (ptid_get_pid (ptid
)) > 1))
3846 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid_get_lwp (ptid
));
3850 return normal_pid_to_str (ptid
);
3854 linux_nat_thread_name (struct target_ops
*self
, struct thread_info
*thr
)
3856 int pid
= ptid_get_pid (thr
->ptid
);
3857 long lwp
= ptid_get_lwp (thr
->ptid
);
3858 #define FORMAT "/proc/%d/task/%ld/comm"
3859 char buf
[sizeof (FORMAT
) + 30];
3861 char *result
= NULL
;
3863 snprintf (buf
, sizeof (buf
), FORMAT
, pid
, lwp
);
3864 comm_file
= gdb_fopen_cloexec (buf
, "r");
3867 /* Not exported by the kernel, so we define it here. */
3869 static char line
[COMM_LEN
+ 1];
3871 if (fgets (line
, sizeof (line
), comm_file
))
3873 char *nl
= strchr (line
, '\n');
3890 /* Accepts an integer PID; Returns a string representing a file that
3891 can be opened to get the symbols for the child process. */
3894 linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
)
3896 static char buf
[PATH_MAX
];
3897 char name
[PATH_MAX
];
3899 xsnprintf (name
, PATH_MAX
, "/proc/%d/exe", pid
);
3900 memset (buf
, 0, PATH_MAX
);
3901 if (readlink (name
, buf
, PATH_MAX
- 1) <= 0)
3907 /* Implement the to_xfer_partial interface for memory reads using the /proc
3908 filesystem. Because we can use a single read() call for /proc, this
3909 can be much more efficient than banging away at PTRACE_PEEKTEXT,
3910 but it doesn't support writes. */
3912 static enum target_xfer_status
3913 linux_proc_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3914 const char *annex
, gdb_byte
*readbuf
,
3915 const gdb_byte
*writebuf
,
3916 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3922 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
3925 /* Don't bother for one word. */
3926 if (len
< 3 * sizeof (long))
3927 return TARGET_XFER_EOF
;
3929 /* We could keep this file open and cache it - possibly one per
3930 thread. That requires some juggling, but is even faster. */
3931 xsnprintf (filename
, sizeof filename
, "/proc/%d/mem",
3932 ptid_get_pid (inferior_ptid
));
3933 fd
= gdb_open_cloexec (filename
, O_RDONLY
| O_LARGEFILE
, 0);
3935 return TARGET_XFER_EOF
;
3937 /* If pread64 is available, use it. It's faster if the kernel
3938 supports it (only one syscall), and it's 64-bit safe even on
3939 32-bit platforms (for instance, SPARC debugging a SPARC64
3942 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
3944 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
3953 return TARGET_XFER_EOF
;
3957 return TARGET_XFER_OK
;
3962 /* Enumerate spufs IDs for process PID. */
3964 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
3966 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
3968 LONGEST written
= 0;
3971 struct dirent
*entry
;
3973 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
3974 dir
= opendir (path
);
3979 while ((entry
= readdir (dir
)) != NULL
)
3985 fd
= atoi (entry
->d_name
);
3989 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
3990 if (stat (path
, &st
) != 0)
3992 if (!S_ISDIR (st
.st_mode
))
3995 if (statfs (path
, &stfs
) != 0)
3997 if (stfs
.f_type
!= SPUFS_MAGIC
)
4000 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
4002 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
4012 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4013 object type, using the /proc file system. */
4015 static enum target_xfer_status
4016 linux_proc_xfer_spu (struct target_ops
*ops
, enum target_object object
,
4017 const char *annex
, gdb_byte
*readbuf
,
4018 const gdb_byte
*writebuf
,
4019 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
4024 int pid
= ptid_get_pid (inferior_ptid
);
4029 return TARGET_XFER_E_IO
;
4032 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4035 return TARGET_XFER_E_IO
;
4037 return TARGET_XFER_EOF
;
4040 *xfered_len
= (ULONGEST
) l
;
4041 return TARGET_XFER_OK
;
4046 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4047 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4049 return TARGET_XFER_E_IO
;
4052 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4055 return TARGET_XFER_EOF
;
4059 ret
= write (fd
, writebuf
, (size_t) len
);
4061 ret
= read (fd
, readbuf
, (size_t) len
);
4066 return TARGET_XFER_E_IO
;
4068 return TARGET_XFER_EOF
;
4071 *xfered_len
= (ULONGEST
) ret
;
4072 return TARGET_XFER_OK
;
4077 /* Parse LINE as a signal set and add its set bits to SIGS. */
4080 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4082 int len
= strlen (line
) - 1;
4086 if (line
[len
] != '\n')
4087 error (_("Could not parse signal set: %s"), line
);
4095 if (*p
>= '0' && *p
<= '9')
4097 else if (*p
>= 'a' && *p
<= 'f')
4098 digit
= *p
- 'a' + 10;
4100 error (_("Could not parse signal set: %s"), line
);
4105 sigaddset (sigs
, signum
+ 1);
4107 sigaddset (sigs
, signum
+ 2);
4109 sigaddset (sigs
, signum
+ 3);
4111 sigaddset (sigs
, signum
+ 4);
4117 /* Find process PID's pending signals from /proc/pid/status and set
4121 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4122 sigset_t
*blocked
, sigset_t
*ignored
)
4125 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4126 struct cleanup
*cleanup
;
4128 sigemptyset (pending
);
4129 sigemptyset (blocked
);
4130 sigemptyset (ignored
);
4131 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4132 procfile
= gdb_fopen_cloexec (fname
, "r");
4133 if (procfile
== NULL
)
4134 error (_("Could not open %s"), fname
);
4135 cleanup
= make_cleanup_fclose (procfile
);
4137 while (fgets (buffer
, PATH_MAX
, procfile
) != NULL
)
4139 /* Normal queued signals are on the SigPnd line in the status
4140 file. However, 2.6 kernels also have a "shared" pending
4141 queue for delivering signals to a thread group, so check for
4144 Unfortunately some Red Hat kernels include the shared pending
4145 queue but not the ShdPnd status field. */
4147 if (strncmp (buffer
, "SigPnd:\t", 8) == 0)
4148 add_line_to_sigset (buffer
+ 8, pending
);
4149 else if (strncmp (buffer
, "ShdPnd:\t", 8) == 0)
4150 add_line_to_sigset (buffer
+ 8, pending
);
4151 else if (strncmp (buffer
, "SigBlk:\t", 8) == 0)
4152 add_line_to_sigset (buffer
+ 8, blocked
);
4153 else if (strncmp (buffer
, "SigIgn:\t", 8) == 0)
4154 add_line_to_sigset (buffer
+ 8, ignored
);
4157 do_cleanups (cleanup
);
4160 static enum target_xfer_status
4161 linux_nat_xfer_osdata (struct target_ops
*ops
, enum target_object object
,
4162 const char *annex
, gdb_byte
*readbuf
,
4163 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4164 ULONGEST
*xfered_len
)
4166 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4168 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4169 if (*xfered_len
== 0)
4170 return TARGET_XFER_EOF
;
4172 return TARGET_XFER_OK
;
4175 static enum target_xfer_status
4176 linux_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4177 const char *annex
, gdb_byte
*readbuf
,
4178 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4179 ULONGEST
*xfered_len
)
4181 enum target_xfer_status xfer
;
4183 if (object
== TARGET_OBJECT_AUXV
)
4184 return memory_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4185 offset
, len
, xfered_len
);
4187 if (object
== TARGET_OBJECT_OSDATA
)
4188 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4189 offset
, len
, xfered_len
);
4191 if (object
== TARGET_OBJECT_SPU
)
4192 return linux_proc_xfer_spu (ops
, object
, annex
, readbuf
, writebuf
,
4193 offset
, len
, xfered_len
);
4195 /* GDB calculates all the addresses in possibly larget width of the address.
4196 Address width needs to be masked before its final use - either by
4197 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4199 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4201 if (object
== TARGET_OBJECT_MEMORY
)
4203 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
4205 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
4206 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
4209 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4210 offset
, len
, xfered_len
);
4211 if (xfer
!= TARGET_XFER_EOF
)
4214 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4215 offset
, len
, xfered_len
);
4219 cleanup_target_stop (void *arg
)
4221 ptid_t
*ptid
= (ptid_t
*) arg
;
4223 gdb_assert (arg
!= NULL
);
4226 target_resume (*ptid
, 0, GDB_SIGNAL_0
);
4229 static VEC(static_tracepoint_marker_p
) *
4230 linux_child_static_tracepoint_markers_by_strid (struct target_ops
*self
,
4233 char s
[IPA_CMD_BUF_SIZE
];
4234 struct cleanup
*old_chain
;
4235 int pid
= ptid_get_pid (inferior_ptid
);
4236 VEC(static_tracepoint_marker_p
) *markers
= NULL
;
4237 struct static_tracepoint_marker
*marker
= NULL
;
4239 ptid_t ptid
= ptid_build (pid
, 0, 0);
4244 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4245 s
[sizeof ("qTfSTM")] = 0;
4247 agent_run_command (pid
, s
, strlen (s
) + 1);
4249 old_chain
= make_cleanup (free_current_marker
, &marker
);
4250 make_cleanup (cleanup_target_stop
, &ptid
);
4255 marker
= XCNEW (struct static_tracepoint_marker
);
4259 parse_static_tracepoint_marker_definition (p
, &p
, marker
);
4261 if (strid
== NULL
|| strcmp (strid
, marker
->str_id
) == 0)
4263 VEC_safe_push (static_tracepoint_marker_p
,
4269 release_static_tracepoint_marker (marker
);
4270 memset (marker
, 0, sizeof (*marker
));
4273 while (*p
++ == ','); /* comma-separated list */
4275 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4276 s
[sizeof ("qTsSTM")] = 0;
4277 agent_run_command (pid
, s
, strlen (s
) + 1);
4281 do_cleanups (old_chain
);
4286 /* Create a prototype generic GNU/Linux target. The client can override
4287 it with local methods. */
4290 linux_target_install_ops (struct target_ops
*t
)
4292 t
->to_insert_fork_catchpoint
= linux_child_insert_fork_catchpoint
;
4293 t
->to_remove_fork_catchpoint
= linux_child_remove_fork_catchpoint
;
4294 t
->to_insert_vfork_catchpoint
= linux_child_insert_vfork_catchpoint
;
4295 t
->to_remove_vfork_catchpoint
= linux_child_remove_vfork_catchpoint
;
4296 t
->to_insert_exec_catchpoint
= linux_child_insert_exec_catchpoint
;
4297 t
->to_remove_exec_catchpoint
= linux_child_remove_exec_catchpoint
;
4298 t
->to_set_syscall_catchpoint
= linux_child_set_syscall_catchpoint
;
4299 t
->to_pid_to_exec_file
= linux_child_pid_to_exec_file
;
4300 t
->to_post_startup_inferior
= linux_child_post_startup_inferior
;
4301 t
->to_post_attach
= linux_child_post_attach
;
4302 t
->to_follow_fork
= linux_child_follow_fork
;
4304 super_xfer_partial
= t
->to_xfer_partial
;
4305 t
->to_xfer_partial
= linux_xfer_partial
;
4307 t
->to_static_tracepoint_markers_by_strid
4308 = linux_child_static_tracepoint_markers_by_strid
;
4314 struct target_ops
*t
;
4316 t
= inf_ptrace_target ();
4317 linux_target_install_ops (t
);
4323 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4325 struct target_ops
*t
;
4327 t
= inf_ptrace_trad_target (register_u_offset
);
4328 linux_target_install_ops (t
);
4333 /* target_is_async_p implementation. */
4336 linux_nat_is_async_p (struct target_ops
*ops
)
4338 /* NOTE: palves 2008-03-21: We're only async when the user requests
4339 it explicitly with the "set target-async" command.
4340 Someday, linux will always be async. */
4341 return target_async_permitted
;
4344 /* target_can_async_p implementation. */
4347 linux_nat_can_async_p (struct target_ops
*ops
)
4349 /* NOTE: palves 2008-03-21: We're only async when the user requests
4350 it explicitly with the "set target-async" command.
4351 Someday, linux will always be async. */
4352 return target_async_permitted
;
4356 linux_nat_supports_non_stop (struct target_ops
*self
)
4361 /* True if we want to support multi-process. To be removed when GDB
4362 supports multi-exec. */
4364 int linux_multi_process
= 1;
4367 linux_nat_supports_multi_process (struct target_ops
*self
)
4369 return linux_multi_process
;
4373 linux_nat_supports_disable_randomization (struct target_ops
*self
)
4375 #ifdef HAVE_PERSONALITY
4382 static int async_terminal_is_ours
= 1;
4384 /* target_terminal_inferior implementation.
4386 This is a wrapper around child_terminal_inferior to add async support. */
4389 linux_nat_terminal_inferior (struct target_ops
*self
)
4391 if (!target_is_async_p ())
4393 /* Async mode is disabled. */
4394 child_terminal_inferior (self
);
4398 child_terminal_inferior (self
);
4400 /* Calls to target_terminal_*() are meant to be idempotent. */
4401 if (!async_terminal_is_ours
)
4404 delete_file_handler (input_fd
);
4405 async_terminal_is_ours
= 0;
4409 /* target_terminal_ours implementation.
4411 This is a wrapper around child_terminal_ours to add async support (and
4412 implement the target_terminal_ours vs target_terminal_ours_for_output
4413 distinction). child_terminal_ours is currently no different than
4414 child_terminal_ours_for_output.
4415 We leave target_terminal_ours_for_output alone, leaving it to
4416 child_terminal_ours_for_output. */
4419 linux_nat_terminal_ours (struct target_ops
*self
)
4421 if (!target_is_async_p ())
4423 /* Async mode is disabled. */
4424 child_terminal_ours (self
);
4428 /* GDB should never give the terminal to the inferior if the
4429 inferior is running in the background (run&, continue&, etc.),
4430 but claiming it sure should. */
4431 child_terminal_ours (self
);
4433 if (async_terminal_is_ours
)
4436 clear_sigint_trap ();
4437 add_file_handler (input_fd
, stdin_event_handler
, 0);
4438 async_terminal_is_ours
= 1;
4441 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4443 static void *async_client_context
;
4445 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4446 so we notice when any child changes state, and notify the
4447 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4448 above to wait for the arrival of a SIGCHLD. */
4451 sigchld_handler (int signo
)
4453 int old_errno
= errno
;
4455 if (debug_linux_nat
)
4456 ui_file_write_async_safe (gdb_stdlog
,
4457 "sigchld\n", sizeof ("sigchld\n") - 1);
4459 if (signo
== SIGCHLD
4460 && linux_nat_event_pipe
[0] != -1)
4461 async_file_mark (); /* Let the event loop know that there are
4462 events to handle. */
4467 /* Callback registered with the target events file descriptor. */
4470 handle_target_event (int error
, gdb_client_data client_data
)
4472 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4475 /* Create/destroy the target events pipe. Returns previous state. */
4478 linux_async_pipe (int enable
)
4480 int previous
= (linux_nat_event_pipe
[0] != -1);
4482 if (previous
!= enable
)
4486 /* Block child signals while we create/destroy the pipe, as
4487 their handler writes to it. */
4488 block_child_signals (&prev_mask
);
4492 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4493 internal_error (__FILE__
, __LINE__
,
4494 "creating event pipe failed.");
4496 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4497 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4501 close (linux_nat_event_pipe
[0]);
4502 close (linux_nat_event_pipe
[1]);
4503 linux_nat_event_pipe
[0] = -1;
4504 linux_nat_event_pipe
[1] = -1;
4507 restore_child_signals_mask (&prev_mask
);
4513 /* target_async implementation. */
4516 linux_nat_async (struct target_ops
*ops
,
4517 void (*callback
) (enum inferior_event_type event_type
,
4521 if (callback
!= NULL
)
4523 async_client_callback
= callback
;
4524 async_client_context
= context
;
4525 if (!linux_async_pipe (1))
4527 add_file_handler (linux_nat_event_pipe
[0],
4528 handle_target_event
, NULL
);
4529 /* There may be pending events to handle. Tell the event loop
4536 async_client_callback
= callback
;
4537 async_client_context
= context
;
4538 delete_file_handler (linux_nat_event_pipe
[0]);
4539 linux_async_pipe (0);
4544 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4548 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4552 if (debug_linux_nat
)
4553 fprintf_unfiltered (gdb_stdlog
,
4554 "LNSL: running -> suspending %s\n",
4555 target_pid_to_str (lwp
->ptid
));
4558 if (lwp
->last_resume_kind
== resume_stop
)
4560 if (debug_linux_nat
)
4561 fprintf_unfiltered (gdb_stdlog
,
4562 "linux-nat: already stopping LWP %ld at "
4564 ptid_get_lwp (lwp
->ptid
));
4568 stop_callback (lwp
, NULL
);
4569 lwp
->last_resume_kind
= resume_stop
;
4573 /* Already known to be stopped; do nothing. */
4575 if (debug_linux_nat
)
4577 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4578 fprintf_unfiltered (gdb_stdlog
,
4579 "LNSL: already stopped/stop_requested %s\n",
4580 target_pid_to_str (lwp
->ptid
));
4582 fprintf_unfiltered (gdb_stdlog
,
4583 "LNSL: already stopped/no "
4584 "stop_requested yet %s\n",
4585 target_pid_to_str (lwp
->ptid
));
4592 linux_nat_stop (struct target_ops
*self
, ptid_t ptid
)
4595 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4597 linux_ops
->to_stop (linux_ops
, ptid
);
4601 linux_nat_close (struct target_ops
*self
)
4603 /* Unregister from the event loop. */
4604 if (linux_nat_is_async_p (self
))
4605 linux_nat_async (self
, NULL
, NULL
);
4607 if (linux_ops
->to_close
)
4608 linux_ops
->to_close (linux_ops
);
4613 /* When requests are passed down from the linux-nat layer to the
4614 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4615 used. The address space pointer is stored in the inferior object,
4616 but the common code that is passed such ptid can't tell whether
4617 lwpid is a "main" process id or not (it assumes so). We reverse
4618 look up the "main" process id from the lwp here. */
4620 static struct address_space
*
4621 linux_nat_thread_address_space (struct target_ops
*t
, ptid_t ptid
)
4623 struct lwp_info
*lwp
;
4624 struct inferior
*inf
;
4627 if (ptid_get_lwp (ptid
) == 0)
4629 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4631 lwp
= find_lwp_pid (ptid
);
4632 pid
= ptid_get_pid (lwp
->ptid
);
4636 /* A (pid,lwpid,0) ptid. */
4637 pid
= ptid_get_pid (ptid
);
4640 inf
= find_inferior_pid (pid
);
4641 gdb_assert (inf
!= NULL
);
4645 /* Return the cached value of the processor core for thread PTID. */
4648 linux_nat_core_of_thread (struct target_ops
*ops
, ptid_t ptid
)
4650 struct lwp_info
*info
= find_lwp_pid (ptid
);
4658 linux_nat_add_target (struct target_ops
*t
)
4660 /* Save the provided single-threaded target. We save this in a separate
4661 variable because another target we've inherited from (e.g. inf-ptrace)
4662 may have saved a pointer to T; we want to use it for the final
4663 process stratum target. */
4664 linux_ops_saved
= *t
;
4665 linux_ops
= &linux_ops_saved
;
4667 /* Override some methods for multithreading. */
4668 t
->to_create_inferior
= linux_nat_create_inferior
;
4669 t
->to_attach
= linux_nat_attach
;
4670 t
->to_detach
= linux_nat_detach
;
4671 t
->to_resume
= linux_nat_resume
;
4672 t
->to_wait
= linux_nat_wait
;
4673 t
->to_pass_signals
= linux_nat_pass_signals
;
4674 t
->to_xfer_partial
= linux_nat_xfer_partial
;
4675 t
->to_kill
= linux_nat_kill
;
4676 t
->to_mourn_inferior
= linux_nat_mourn_inferior
;
4677 t
->to_thread_alive
= linux_nat_thread_alive
;
4678 t
->to_pid_to_str
= linux_nat_pid_to_str
;
4679 t
->to_thread_name
= linux_nat_thread_name
;
4680 t
->to_has_thread_control
= tc_schedlock
;
4681 t
->to_thread_address_space
= linux_nat_thread_address_space
;
4682 t
->to_stopped_by_watchpoint
= linux_nat_stopped_by_watchpoint
;
4683 t
->to_stopped_data_address
= linux_nat_stopped_data_address
;
4685 t
->to_can_async_p
= linux_nat_can_async_p
;
4686 t
->to_is_async_p
= linux_nat_is_async_p
;
4687 t
->to_supports_non_stop
= linux_nat_supports_non_stop
;
4688 t
->to_async
= linux_nat_async
;
4689 t
->to_terminal_inferior
= linux_nat_terminal_inferior
;
4690 t
->to_terminal_ours
= linux_nat_terminal_ours
;
4692 super_close
= t
->to_close
;
4693 t
->to_close
= linux_nat_close
;
4695 /* Methods for non-stop support. */
4696 t
->to_stop
= linux_nat_stop
;
4698 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
4700 t
->to_supports_disable_randomization
4701 = linux_nat_supports_disable_randomization
;
4703 t
->to_core_of_thread
= linux_nat_core_of_thread
;
4705 /* We don't change the stratum; this target will sit at
4706 process_stratum and thread_db will set at thread_stratum. This
4707 is a little strange, since this is a multi-threaded-capable
4708 target, but we want to be on the stack below thread_db, and we
4709 also want to be used for single-threaded processes. */
4714 /* Register a method to call whenever a new thread is attached. */
4716 linux_nat_set_new_thread (struct target_ops
*t
,
4717 void (*new_thread
) (struct lwp_info
*))
4719 /* Save the pointer. We only support a single registered instance
4720 of the GNU/Linux native target, so we do not need to map this to
4722 linux_nat_new_thread
= new_thread
;
4725 /* See declaration in linux-nat.h. */
4728 linux_nat_set_new_fork (struct target_ops
*t
,
4729 linux_nat_new_fork_ftype
*new_fork
)
4731 /* Save the pointer. */
4732 linux_nat_new_fork
= new_fork
;
4735 /* See declaration in linux-nat.h. */
4738 linux_nat_set_forget_process (struct target_ops
*t
,
4739 linux_nat_forget_process_ftype
*fn
)
4741 /* Save the pointer. */
4742 linux_nat_forget_process_hook
= fn
;
4745 /* See declaration in linux-nat.h. */
4748 linux_nat_forget_process (pid_t pid
)
4750 if (linux_nat_forget_process_hook
!= NULL
)
4751 linux_nat_forget_process_hook (pid
);
4754 /* Register a method that converts a siginfo object between the layout
4755 that ptrace returns, and the layout in the architecture of the
4758 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4759 int (*siginfo_fixup
) (siginfo_t
*,
4763 /* Save the pointer. */
4764 linux_nat_siginfo_fixup
= siginfo_fixup
;
4767 /* Register a method to call prior to resuming a thread. */
4770 linux_nat_set_prepare_to_resume (struct target_ops
*t
,
4771 void (*prepare_to_resume
) (struct lwp_info
*))
4773 /* Save the pointer. */
4774 linux_nat_prepare_to_resume
= prepare_to_resume
;
4777 /* See linux-nat.h. */
4780 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4784 pid
= ptid_get_lwp (ptid
);
4786 pid
= ptid_get_pid (ptid
);
4789 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4792 memset (siginfo
, 0, sizeof (*siginfo
));
4798 /* Provide a prototype to silence -Wmissing-prototypes. */
4799 extern initialize_file_ftype _initialize_linux_nat
;
4802 _initialize_linux_nat (void)
4804 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4805 &debug_linux_nat
, _("\
4806 Set debugging of GNU/Linux lwp module."), _("\
4807 Show debugging of GNU/Linux lwp module."), _("\
4808 Enables printf debugging output."),
4810 show_debug_linux_nat
,
4811 &setdebuglist
, &showdebuglist
);
4813 /* Save this mask as the default. */
4814 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
4816 /* Install a SIGCHLD handler. */
4817 sigchld_action
.sa_handler
= sigchld_handler
;
4818 sigemptyset (&sigchld_action
.sa_mask
);
4819 sigchld_action
.sa_flags
= SA_RESTART
;
4821 /* Make it the default. */
4822 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4824 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4825 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4826 sigdelset (&suspend_mask
, SIGCHLD
);
4828 sigemptyset (&blocked_mask
);
4830 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
4831 support read-only process state. */
4832 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
4833 | PTRACE_O_TRACEVFORKDONE
4834 | PTRACE_O_TRACEVFORK
4835 | PTRACE_O_TRACEFORK
4836 | PTRACE_O_TRACEEXEC
);
4840 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4841 the GNU/Linux Threads library and therefore doesn't really belong
4844 /* Read variable NAME in the target and return its value if found.
4845 Otherwise return zero. It is assumed that the type of the variable
4849 get_signo (const char *name
)
4851 struct bound_minimal_symbol ms
;
4854 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
4855 if (ms
.minsym
== NULL
)
4858 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
4859 sizeof (signo
)) != 0)
4865 /* Return the set of signals used by the threads library in *SET. */
4868 lin_thread_get_thread_signals (sigset_t
*set
)
4870 struct sigaction action
;
4871 int restart
, cancel
;
4873 sigemptyset (&blocked_mask
);
4876 restart
= get_signo ("__pthread_sig_restart");
4877 cancel
= get_signo ("__pthread_sig_cancel");
4879 /* LinuxThreads normally uses the first two RT signals, but in some legacy
4880 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
4881 not provide any way for the debugger to query the signal numbers -
4882 fortunately they don't change! */
4885 restart
= __SIGRTMIN
;
4888 cancel
= __SIGRTMIN
+ 1;
4890 sigaddset (set
, restart
);
4891 sigaddset (set
, cancel
);
4893 /* The GNU/Linux Threads library makes terminating threads send a
4894 special "cancel" signal instead of SIGCHLD. Make sure we catch
4895 those (to prevent them from terminating GDB itself, which is
4896 likely to be their default action) and treat them the same way as
4899 action
.sa_handler
= sigchld_handler
;
4900 sigemptyset (&action
.sa_mask
);
4901 action
.sa_flags
= SA_RESTART
;
4902 sigaction (cancel
, &action
, NULL
);
4904 /* We block the "cancel" signal throughout this code ... */
4905 sigaddset (&blocked_mask
, cancel
);
4906 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
4908 /* ... except during a sigsuspend. */
4909 sigdelset (&suspend_mask
, cancel
);