1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2015 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
27 #ifdef HAVE_TKILL_SYSCALL
29 #include <sys/syscall.h>
31 #include <sys/ptrace.h>
32 #include "linux-nat.h"
33 #include "nat/linux-ptrace.h"
34 #include "nat/linux-procfs.h"
35 #include "nat/linux-personality.h"
36 #include "linux-fork.h"
37 #include "gdbthread.h"
41 #include "inf-child.h"
42 #include "inf-ptrace.h"
44 #include <sys/procfs.h> /* for elf_gregset etc. */
45 #include "elf-bfd.h" /* for elfcore_write_* */
46 #include "gregset.h" /* for gregset */
47 #include "gdbcore.h" /* for get_exec_file */
48 #include <ctype.h> /* for isdigit */
49 #include <sys/stat.h> /* for struct stat */
50 #include <fcntl.h> /* for O_RDONLY */
52 #include "event-loop.h"
53 #include "event-top.h"
55 #include <sys/types.h>
57 #include "xml-support.h"
60 #include "nat/linux-osdata.h"
61 #include "linux-tdep.h"
64 #include "tracepoint.h"
66 #include "target-descriptions.h"
67 #include "filestuff.h"
71 #define SPUFS_MAGIC 0x23c9b64e
74 /* This comment documents high-level logic of this file.
76 Waiting for events in sync mode
77 ===============================
79 When waiting for an event in a specific thread, we just use waitpid, passing
80 the specific pid, and not passing WNOHANG.
82 When waiting for an event in all threads, waitpid is not quite good. Prior to
83 version 2.4, Linux can either wait for event in main thread, or in secondary
84 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
85 miss an event. The solution is to use non-blocking waitpid, together with
86 sigsuspend. First, we use non-blocking waitpid to get an event in the main
87 process, if any. Second, we use non-blocking waitpid with the __WCLONED
88 flag to check for events in cloned processes. If nothing is found, we use
89 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
90 happened to a child process -- and SIGCHLD will be delivered both for events
91 in main debugged process and in cloned processes. As soon as we know there's
92 an event, we get back to calling nonblocking waitpid with and without
95 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
96 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
97 blocked, the signal becomes pending and sigsuspend immediately
98 notices it and returns.
100 Waiting for events in async mode
101 ================================
103 In async mode, GDB should always be ready to handle both user input
104 and target events, so neither blocking waitpid nor sigsuspend are
105 viable options. Instead, we should asynchronously notify the GDB main
106 event loop whenever there's an unprocessed event from the target. We
107 detect asynchronous target events by handling SIGCHLD signals. To
108 notify the event loop about target events, the self-pipe trick is used
109 --- a pipe is registered as waitable event source in the event loop,
110 the event loop select/poll's on the read end of this pipe (as well on
111 other event sources, e.g., stdin), and the SIGCHLD handler writes a
112 byte to this pipe. This is more portable than relying on
113 pselect/ppoll, since on kernels that lack those syscalls, libc
114 emulates them with select/poll+sigprocmask, and that is racy
115 (a.k.a. plain broken).
117 Obviously, if we fail to notify the event loop if there's a target
118 event, it's bad. OTOH, if we notify the event loop when there's no
119 event from the target, linux_nat_wait will detect that there's no real
120 event to report, and return event of type TARGET_WAITKIND_IGNORE.
121 This is mostly harmless, but it will waste time and is better avoided.
123 The main design point is that every time GDB is outside linux-nat.c,
124 we have a SIGCHLD handler installed that is called when something
125 happens to the target and notifies the GDB event loop. Whenever GDB
126 core decides to handle the event, and calls into linux-nat.c, we
127 process things as in sync mode, except that the we never block in
130 While processing an event, we may end up momentarily blocked in
131 waitpid calls. Those waitpid calls, while blocking, are guarantied to
132 return quickly. E.g., in all-stop mode, before reporting to the core
133 that an LWP hit a breakpoint, all LWPs are stopped by sending them
134 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
135 Note that this is different from blocking indefinitely waiting for the
136 next event --- here, we're already handling an event.
141 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
142 signal is not entirely significant; we just need for a signal to be delivered,
143 so that we can intercept it. SIGSTOP's advantage is that it can not be
144 blocked. A disadvantage is that it is not a real-time signal, so it can only
145 be queued once; we do not keep track of other sources of SIGSTOP.
147 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
148 use them, because they have special behavior when the signal is generated -
149 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
150 kills the entire thread group.
152 A delivered SIGSTOP would stop the entire thread group, not just the thread we
153 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
154 cancel it (by PTRACE_CONT without passing SIGSTOP).
156 We could use a real-time signal instead. This would solve those problems; we
157 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
158 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
159 generates it, and there are races with trying to find a signal that is not
163 #define O_LARGEFILE 0
166 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
167 the use of the multi-threaded target. */
168 static struct target_ops
*linux_ops
;
169 static struct target_ops linux_ops_saved
;
171 /* The method to call, if any, when a new thread is attached. */
172 static void (*linux_nat_new_thread
) (struct lwp_info
*);
174 /* The method to call, if any, when a new fork is attached. */
175 static linux_nat_new_fork_ftype
*linux_nat_new_fork
;
177 /* The method to call, if any, when a process is no longer
179 static linux_nat_forget_process_ftype
*linux_nat_forget_process_hook
;
181 /* Hook to call prior to resuming a thread. */
182 static void (*linux_nat_prepare_to_resume
) (struct lwp_info
*);
184 /* The method to call, if any, when the siginfo object needs to be
185 converted between the layout returned by ptrace, and the layout in
186 the architecture of the inferior. */
187 static int (*linux_nat_siginfo_fixup
) (siginfo_t
*,
191 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
192 Called by our to_xfer_partial. */
193 static target_xfer_partial_ftype
*super_xfer_partial
;
195 /* The saved to_close method, inherited from inf-ptrace.c.
196 Called by our to_close. */
197 static void (*super_close
) (struct target_ops
*);
199 static unsigned int debug_linux_nat
;
201 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
202 struct cmd_list_element
*c
, const char *value
)
204 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
208 struct simple_pid_list
212 struct simple_pid_list
*next
;
214 struct simple_pid_list
*stopped_pids
;
216 /* Async mode support. */
218 /* The read/write ends of the pipe registered as waitable file in the
220 static int linux_nat_event_pipe
[2] = { -1, -1 };
222 /* True if we're currently in async mode. */
223 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
225 /* Flush the event pipe. */
228 async_file_flush (void)
235 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
237 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
240 /* Put something (anything, doesn't matter what, or how much) in event
241 pipe, so that the select/poll in the event-loop realizes we have
242 something to process. */
245 async_file_mark (void)
249 /* It doesn't really matter what the pipe contains, as long we end
250 up with something in it. Might as well flush the previous
256 ret
= write (linux_nat_event_pipe
[1], "+", 1);
258 while (ret
== -1 && errno
== EINTR
);
260 /* Ignore EAGAIN. If the pipe is full, the event loop will already
261 be awakened anyway. */
264 static int kill_lwp (int lwpid
, int signo
);
266 static int stop_callback (struct lwp_info
*lp
, void *data
);
268 static void block_child_signals (sigset_t
*prev_mask
);
269 static void restore_child_signals_mask (sigset_t
*prev_mask
);
272 static struct lwp_info
*add_lwp (ptid_t ptid
);
273 static void purge_lwp_list (int pid
);
274 static void delete_lwp (ptid_t ptid
);
275 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
277 static int lwp_status_pending_p (struct lwp_info
*lp
);
279 static int check_stopped_by_breakpoint (struct lwp_info
*lp
);
280 static int sigtrap_is_event (int status
);
281 static int (*linux_nat_status_is_event
) (int status
) = sigtrap_is_event
;
284 /* Trivial list manipulation functions to keep track of a list of
285 new stopped processes. */
287 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
289 struct simple_pid_list
*new_pid
= xmalloc (sizeof (struct simple_pid_list
));
292 new_pid
->status
= status
;
293 new_pid
->next
= *listp
;
298 in_pid_list_p (struct simple_pid_list
*list
, int pid
)
300 struct simple_pid_list
*p
;
302 for (p
= list
; p
!= NULL
; p
= p
->next
)
309 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
311 struct simple_pid_list
**p
;
313 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
314 if ((*p
)->pid
== pid
)
316 struct simple_pid_list
*next
= (*p
)->next
;
318 *statusp
= (*p
)->status
;
326 /* Initialize ptrace warnings and check for supported ptrace
329 ATTACHED should be nonzero iff we attached to the inferior. */
332 linux_init_ptrace (pid_t pid
, int attached
)
334 linux_enable_event_reporting (pid
, attached
);
335 linux_ptrace_init_warnings ();
339 linux_child_post_attach (struct target_ops
*self
, int pid
)
341 linux_init_ptrace (pid
, 1);
345 linux_child_post_startup_inferior (struct target_ops
*self
, ptid_t ptid
)
347 linux_init_ptrace (ptid_get_pid (ptid
), 0);
350 /* Return the number of known LWPs in the tgid given by PID. */
358 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
359 if (ptid_get_pid (lp
->ptid
) == pid
)
365 /* Call delete_lwp with prototype compatible for make_cleanup. */
368 delete_lwp_cleanup (void *lp_voidp
)
370 struct lwp_info
*lp
= lp_voidp
;
372 delete_lwp (lp
->ptid
);
375 /* Target hook for follow_fork. On entry inferior_ptid must be the
376 ptid of the followed inferior. At return, inferior_ptid will be
380 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
,
385 struct lwp_info
*child_lp
= NULL
;
386 int status
= W_STOPCODE (0);
387 struct cleanup
*old_chain
;
389 int parent_pid
, child_pid
;
391 has_vforked
= (inferior_thread ()->pending_follow
.kind
392 == TARGET_WAITKIND_VFORKED
);
393 parent_pid
= ptid_get_lwp (inferior_ptid
);
395 parent_pid
= ptid_get_pid (inferior_ptid
);
397 = ptid_get_pid (inferior_thread ()->pending_follow
.value
.related_pid
);
400 /* We're already attached to the parent, by default. */
401 old_chain
= save_inferior_ptid ();
402 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
403 child_lp
= add_lwp (inferior_ptid
);
404 child_lp
->stopped
= 1;
405 child_lp
->last_resume_kind
= resume_stop
;
407 /* Detach new forked process? */
410 make_cleanup (delete_lwp_cleanup
, child_lp
);
412 if (linux_nat_prepare_to_resume
!= NULL
)
413 linux_nat_prepare_to_resume (child_lp
);
415 /* When debugging an inferior in an architecture that supports
416 hardware single stepping on a kernel without commit
417 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
418 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
419 set if the parent process had them set.
420 To work around this, single step the child process
421 once before detaching to clear the flags. */
423 if (!gdbarch_software_single_step_p (target_thread_architecture
426 linux_disable_event_reporting (child_pid
);
427 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
428 perror_with_name (_("Couldn't do single step"));
429 if (my_waitpid (child_pid
, &status
, 0) < 0)
430 perror_with_name (_("Couldn't wait vfork process"));
433 if (WIFSTOPPED (status
))
437 signo
= WSTOPSIG (status
);
439 && !signal_pass_state (gdb_signal_from_host (signo
)))
441 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
444 /* Resets value of inferior_ptid to parent ptid. */
445 do_cleanups (old_chain
);
449 /* Let the thread_db layer learn about this new process. */
450 check_for_thread_db ();
453 do_cleanups (old_chain
);
457 struct lwp_info
*parent_lp
;
459 parent_lp
= find_lwp_pid (pid_to_ptid (parent_pid
));
460 gdb_assert (linux_supports_tracefork () >= 0);
462 if (linux_supports_tracevforkdone ())
465 fprintf_unfiltered (gdb_stdlog
,
466 "LCFF: waiting for VFORK_DONE on %d\n",
468 parent_lp
->stopped
= 1;
470 /* We'll handle the VFORK_DONE event like any other
471 event, in target_wait. */
475 /* We can't insert breakpoints until the child has
476 finished with the shared memory region. We need to
477 wait until that happens. Ideal would be to just
479 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
480 - waitpid (parent_pid, &status, __WALL);
481 However, most architectures can't handle a syscall
482 being traced on the way out if it wasn't traced on
485 We might also think to loop, continuing the child
486 until it exits or gets a SIGTRAP. One problem is
487 that the child might call ptrace with PTRACE_TRACEME.
489 There's no simple and reliable way to figure out when
490 the vforked child will be done with its copy of the
491 shared memory. We could step it out of the syscall,
492 two instructions, let it go, and then single-step the
493 parent once. When we have hardware single-step, this
494 would work; with software single-step it could still
495 be made to work but we'd have to be able to insert
496 single-step breakpoints in the child, and we'd have
497 to insert -just- the single-step breakpoint in the
498 parent. Very awkward.
500 In the end, the best we can do is to make sure it
501 runs for a little while. Hopefully it will be out of
502 range of any breakpoints we reinsert. Usually this
503 is only the single-step breakpoint at vfork's return
507 fprintf_unfiltered (gdb_stdlog
,
508 "LCFF: no VFORK_DONE "
509 "support, sleeping a bit\n");
513 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
514 and leave it pending. The next linux_nat_resume call
515 will notice a pending event, and bypasses actually
516 resuming the inferior. */
517 parent_lp
->status
= 0;
518 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
519 parent_lp
->stopped
= 1;
521 /* If we're in async mode, need to tell the event loop
522 there's something here to process. */
523 if (target_can_async_p ())
530 struct lwp_info
*child_lp
;
532 child_lp
= add_lwp (inferior_ptid
);
533 child_lp
->stopped
= 1;
534 child_lp
->last_resume_kind
= resume_stop
;
536 /* Let the thread_db layer learn about this new process. */
537 check_for_thread_db ();
545 linux_child_insert_fork_catchpoint (struct target_ops
*self
, int pid
)
547 return !linux_supports_tracefork ();
551 linux_child_remove_fork_catchpoint (struct target_ops
*self
, int pid
)
557 linux_child_insert_vfork_catchpoint (struct target_ops
*self
, int pid
)
559 return !linux_supports_tracefork ();
563 linux_child_remove_vfork_catchpoint (struct target_ops
*self
, int pid
)
569 linux_child_insert_exec_catchpoint (struct target_ops
*self
, int pid
)
571 return !linux_supports_tracefork ();
575 linux_child_remove_exec_catchpoint (struct target_ops
*self
, int pid
)
581 linux_child_set_syscall_catchpoint (struct target_ops
*self
,
582 int pid
, int needed
, int any_count
,
583 int table_size
, int *table
)
585 if (!linux_supports_tracesysgood ())
588 /* On GNU/Linux, we ignore the arguments. It means that we only
589 enable the syscall catchpoints, but do not disable them.
591 Also, we do not use the `table' information because we do not
592 filter system calls here. We let GDB do the logic for us. */
596 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
597 are processes sharing the same VM space. A multi-threaded process
598 is basically a group of such processes. However, such a grouping
599 is almost entirely a user-space issue; the kernel doesn't enforce
600 such a grouping at all (this might change in the future). In
601 general, we'll rely on the threads library (i.e. the GNU/Linux
602 Threads library) to provide such a grouping.
604 It is perfectly well possible to write a multi-threaded application
605 without the assistance of a threads library, by using the clone
606 system call directly. This module should be able to give some
607 rudimentary support for debugging such applications if developers
608 specify the CLONE_PTRACE flag in the clone system call, and are
609 using the Linux kernel 2.4 or above.
611 Note that there are some peculiarities in GNU/Linux that affect
614 - In general one should specify the __WCLONE flag to waitpid in
615 order to make it report events for any of the cloned processes
616 (and leave it out for the initial process). However, if a cloned
617 process has exited the exit status is only reported if the
618 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
619 we cannot use it since GDB must work on older systems too.
621 - When a traced, cloned process exits and is waited for by the
622 debugger, the kernel reassigns it to the original parent and
623 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
624 library doesn't notice this, which leads to the "zombie problem":
625 When debugged a multi-threaded process that spawns a lot of
626 threads will run out of processes, even if the threads exit,
627 because the "zombies" stay around. */
629 /* List of known LWPs. */
630 struct lwp_info
*lwp_list
;
633 /* Original signal mask. */
634 static sigset_t normal_mask
;
636 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
637 _initialize_linux_nat. */
638 static sigset_t suspend_mask
;
640 /* Signals to block to make that sigsuspend work. */
641 static sigset_t blocked_mask
;
643 /* SIGCHLD action. */
644 struct sigaction sigchld_action
;
646 /* Block child signals (SIGCHLD and linux threads signals), and store
647 the previous mask in PREV_MASK. */
650 block_child_signals (sigset_t
*prev_mask
)
652 /* Make sure SIGCHLD is blocked. */
653 if (!sigismember (&blocked_mask
, SIGCHLD
))
654 sigaddset (&blocked_mask
, SIGCHLD
);
656 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
659 /* Restore child signals mask, previously returned by
660 block_child_signals. */
663 restore_child_signals_mask (sigset_t
*prev_mask
)
665 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
668 /* Mask of signals to pass directly to the inferior. */
669 static sigset_t pass_mask
;
671 /* Update signals to pass to the inferior. */
673 linux_nat_pass_signals (struct target_ops
*self
,
674 int numsigs
, unsigned char *pass_signals
)
678 sigemptyset (&pass_mask
);
680 for (signo
= 1; signo
< NSIG
; signo
++)
682 int target_signo
= gdb_signal_from_host (signo
);
683 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
684 sigaddset (&pass_mask
, signo
);
690 /* Prototypes for local functions. */
691 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
692 static int linux_thread_alive (ptid_t ptid
);
693 static char *linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
);
697 /* Destroy and free LP. */
700 lwp_free (struct lwp_info
*lp
)
702 xfree (lp
->arch_private
);
706 /* Remove all LWPs belong to PID from the lwp list. */
709 purge_lwp_list (int pid
)
711 struct lwp_info
*lp
, *lpprev
, *lpnext
;
715 for (lp
= lwp_list
; lp
; lp
= lpnext
)
719 if (ptid_get_pid (lp
->ptid
) == pid
)
724 lpprev
->next
= lp
->next
;
733 /* Add the LWP specified by PTID to the list. PTID is the first LWP
734 in the process. Return a pointer to the structure describing the
737 This differs from add_lwp in that we don't let the arch specific
738 bits know about this new thread. Current clients of this callback
739 take the opportunity to install watchpoints in the new thread, and
740 we shouldn't do that for the first thread. If we're spawning a
741 child ("run"), the thread executes the shell wrapper first, and we
742 shouldn't touch it until it execs the program we want to debug.
743 For "attach", it'd be okay to call the callback, but it's not
744 necessary, because watchpoints can't yet have been inserted into
747 static struct lwp_info
*
748 add_initial_lwp (ptid_t ptid
)
752 gdb_assert (ptid_lwp_p (ptid
));
754 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
756 memset (lp
, 0, sizeof (struct lwp_info
));
758 lp
->last_resume_kind
= resume_continue
;
759 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
770 /* Add the LWP specified by PID to the list. Return a pointer to the
771 structure describing the new LWP. The LWP should already be
774 static struct lwp_info
*
775 add_lwp (ptid_t ptid
)
779 lp
= add_initial_lwp (ptid
);
781 /* Let the arch specific bits know about this new thread. Current
782 clients of this callback take the opportunity to install
783 watchpoints in the new thread. We don't do this for the first
784 thread though. See add_initial_lwp. */
785 if (linux_nat_new_thread
!= NULL
)
786 linux_nat_new_thread (lp
);
791 /* Remove the LWP specified by PID from the list. */
794 delete_lwp (ptid_t ptid
)
796 struct lwp_info
*lp
, *lpprev
;
800 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
801 if (ptid_equal (lp
->ptid
, ptid
))
808 lpprev
->next
= lp
->next
;
815 /* Return a pointer to the structure describing the LWP corresponding
816 to PID. If no corresponding LWP could be found, return NULL. */
818 static struct lwp_info
*
819 find_lwp_pid (ptid_t ptid
)
824 if (ptid_lwp_p (ptid
))
825 lwp
= ptid_get_lwp (ptid
);
827 lwp
= ptid_get_pid (ptid
);
829 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
830 if (lwp
== ptid_get_lwp (lp
->ptid
))
836 /* Call CALLBACK with its second argument set to DATA for every LWP in
837 the list. If CALLBACK returns 1 for a particular LWP, return a
838 pointer to the structure describing that LWP immediately.
839 Otherwise return NULL. */
842 iterate_over_lwps (ptid_t filter
,
843 int (*callback
) (struct lwp_info
*, void *),
846 struct lwp_info
*lp
, *lpnext
;
848 for (lp
= lwp_list
; lp
; lp
= lpnext
)
852 if (ptid_match (lp
->ptid
, filter
))
854 if ((*callback
) (lp
, data
))
862 /* Update our internal state when changing from one checkpoint to
863 another indicated by NEW_PTID. We can only switch single-threaded
864 applications, so we only create one new LWP, and the previous list
868 linux_nat_switch_fork (ptid_t new_ptid
)
872 purge_lwp_list (ptid_get_pid (inferior_ptid
));
874 lp
= add_lwp (new_ptid
);
877 /* This changes the thread's ptid while preserving the gdb thread
878 num. Also changes the inferior pid, while preserving the
880 thread_change_ptid (inferior_ptid
, new_ptid
);
882 /* We've just told GDB core that the thread changed target id, but,
883 in fact, it really is a different thread, with different register
885 registers_changed ();
888 /* Handle the exit of a single thread LP. */
891 exit_lwp (struct lwp_info
*lp
)
893 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
897 if (print_thread_events
)
898 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
900 delete_thread (lp
->ptid
);
903 delete_lwp (lp
->ptid
);
906 /* Wait for the LWP specified by LP, which we have just attached to.
907 Returns a wait status for that LWP, to cache. */
910 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
913 pid_t new_pid
, pid
= ptid_get_lwp (ptid
);
916 if (linux_proc_pid_is_stopped (pid
))
919 fprintf_unfiltered (gdb_stdlog
,
920 "LNPAW: Attaching to a stopped process\n");
922 /* The process is definitely stopped. It is in a job control
923 stop, unless the kernel predates the TASK_STOPPED /
924 TASK_TRACED distinction, in which case it might be in a
925 ptrace stop. Make sure it is in a ptrace stop; from there we
926 can kill it, signal it, et cetera.
928 First make sure there is a pending SIGSTOP. Since we are
929 already attached, the process can not transition from stopped
930 to running without a PTRACE_CONT; so we know this signal will
931 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
932 probably already in the queue (unless this kernel is old
933 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
934 is not an RT signal, it can only be queued once. */
935 kill_lwp (pid
, SIGSTOP
);
937 /* Finally, resume the stopped process. This will deliver the SIGSTOP
938 (or a higher priority signal, just like normal PTRACE_ATTACH). */
939 ptrace (PTRACE_CONT
, pid
, 0, 0);
942 /* Make sure the initial process is stopped. The user-level threads
943 layer might want to poke around in the inferior, and that won't
944 work if things haven't stabilized yet. */
945 new_pid
= my_waitpid (pid
, &status
, 0);
946 if (new_pid
== -1 && errno
== ECHILD
)
949 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
951 /* Try again with __WCLONE to check cloned processes. */
952 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
956 gdb_assert (pid
== new_pid
);
958 if (!WIFSTOPPED (status
))
960 /* The pid we tried to attach has apparently just exited. */
962 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
963 pid
, status_to_str (status
));
967 if (WSTOPSIG (status
) != SIGSTOP
)
971 fprintf_unfiltered (gdb_stdlog
,
972 "LNPAW: Received %s after attaching\n",
973 status_to_str (status
));
979 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
980 the new LWP could not be attached, or 1 if we're already auto
981 attached to this thread, but haven't processed the
982 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
983 its existance, without considering it an error. */
986 lin_lwp_attach_lwp (ptid_t ptid
)
991 gdb_assert (ptid_lwp_p (ptid
));
993 lp
= find_lwp_pid (ptid
);
994 lwpid
= ptid_get_lwp (ptid
);
996 /* We assume that we're already attached to any LWP that has an id
997 equal to the overall process id, and to any LWP that is already
998 in our list of LWPs. If we're not seeing exit events from threads
999 and we've had PID wraparound since we last tried to stop all threads,
1000 this assumption might be wrong; fortunately, this is very unlikely
1002 if (lwpid
!= ptid_get_pid (ptid
) && lp
== NULL
)
1004 int status
, cloned
= 0, signalled
= 0;
1006 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1008 if (linux_supports_tracefork ())
1010 /* If we haven't stopped all threads when we get here,
1011 we may have seen a thread listed in thread_db's list,
1012 but not processed the PTRACE_EVENT_CLONE yet. If
1013 that's the case, ignore this new thread, and let
1014 normal event handling discover it later. */
1015 if (in_pid_list_p (stopped_pids
, lwpid
))
1017 /* We've already seen this thread stop, but we
1018 haven't seen the PTRACE_EVENT_CLONE extended
1027 /* See if we've got a stop for this new child
1028 pending. If so, we're already attached. */
1029 gdb_assert (lwpid
> 0);
1030 new_pid
= my_waitpid (lwpid
, &status
, WNOHANG
);
1031 if (new_pid
== -1 && errno
== ECHILD
)
1032 new_pid
= my_waitpid (lwpid
, &status
, __WCLONE
| WNOHANG
);
1035 if (WIFSTOPPED (status
))
1036 add_to_pid_list (&stopped_pids
, lwpid
, status
);
1042 /* If we fail to attach to the thread, issue a warning,
1043 but continue. One way this can happen is if thread
1044 creation is interrupted; as of Linux kernel 2.6.19, a
1045 bug may place threads in the thread list and then fail
1047 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1048 safe_strerror (errno
));
1052 if (debug_linux_nat
)
1053 fprintf_unfiltered (gdb_stdlog
,
1054 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1055 target_pid_to_str (ptid
));
1057 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1058 if (!WIFSTOPPED (status
))
1061 lp
= add_lwp (ptid
);
1063 lp
->cloned
= cloned
;
1064 lp
->signalled
= signalled
;
1065 if (WSTOPSIG (status
) != SIGSTOP
)
1068 lp
->status
= status
;
1071 target_post_attach (ptid_get_lwp (lp
->ptid
));
1073 if (debug_linux_nat
)
1075 fprintf_unfiltered (gdb_stdlog
,
1076 "LLAL: waitpid %s received %s\n",
1077 target_pid_to_str (ptid
),
1078 status_to_str (status
));
1083 /* We assume that the LWP representing the original process is
1084 already stopped. Mark it as stopped in the data structure
1085 that the GNU/linux ptrace layer uses to keep track of
1086 threads. Note that this won't have already been done since
1087 the main thread will have, we assume, been stopped by an
1088 attach from a different layer. */
1090 lp
= add_lwp (ptid
);
1094 lp
->last_resume_kind
= resume_stop
;
1099 linux_nat_create_inferior (struct target_ops
*ops
,
1100 char *exec_file
, char *allargs
, char **env
,
1103 struct cleanup
*restore_personality
1104 = maybe_disable_address_space_randomization (disable_randomization
);
1106 /* The fork_child mechanism is synchronous and calls target_wait, so
1107 we have to mask the async mode. */
1109 /* Make sure we report all signals during startup. */
1110 linux_nat_pass_signals (ops
, 0, NULL
);
1112 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1114 do_cleanups (restore_personality
);
1117 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1118 already attached. Returns true if a new LWP is found, false
1122 attach_proc_task_lwp_callback (ptid_t ptid
)
1124 struct lwp_info
*lp
;
1126 /* Ignore LWPs we're already attached to. */
1127 lp
= find_lwp_pid (ptid
);
1130 int lwpid
= ptid_get_lwp (ptid
);
1132 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1136 /* Be quiet if we simply raced with the thread exiting.
1137 EPERM is returned if the thread's task still exists, and
1138 is marked as exited or zombie, as well as other
1139 conditions, so in that case, confirm the status in
1140 /proc/PID/status. */
1142 || (err
== EPERM
&& linux_proc_pid_is_gone (lwpid
)))
1144 if (debug_linux_nat
)
1146 fprintf_unfiltered (gdb_stdlog
,
1147 "Cannot attach to lwp %d: "
1148 "thread is gone (%d: %s)\n",
1149 lwpid
, err
, safe_strerror (err
));
1154 warning (_("Cannot attach to lwp %d: %s"),
1156 linux_ptrace_attach_fail_reason_string (ptid
,
1162 if (debug_linux_nat
)
1163 fprintf_unfiltered (gdb_stdlog
,
1164 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1165 target_pid_to_str (ptid
));
1167 lp
= add_lwp (ptid
);
1170 /* The next time we wait for this LWP we'll see a SIGSTOP as
1171 PTRACE_ATTACH brings it to a halt. */
1174 /* We need to wait for a stop before being able to make the
1175 next ptrace call on this LWP. */
1176 lp
->must_set_ptrace_flags
= 1;
1185 linux_nat_attach (struct target_ops
*ops
, const char *args
, int from_tty
)
1187 struct lwp_info
*lp
;
1190 volatile struct gdb_exception ex
;
1192 /* Make sure we report all signals during attach. */
1193 linux_nat_pass_signals (ops
, 0, NULL
);
1195 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
1197 linux_ops
->to_attach (ops
, args
, from_tty
);
1201 pid_t pid
= parse_pid_to_attach (args
);
1202 struct buffer buffer
;
1203 char *message
, *buffer_s
;
1205 message
= xstrdup (ex
.message
);
1206 make_cleanup (xfree
, message
);
1208 buffer_init (&buffer
);
1209 linux_ptrace_attach_fail_reason (pid
, &buffer
);
1211 buffer_grow_str0 (&buffer
, "");
1212 buffer_s
= buffer_finish (&buffer
);
1213 make_cleanup (xfree
, buffer_s
);
1215 if (*buffer_s
!= '\0')
1216 throw_error (ex
.error
, "warning: %s\n%s", buffer_s
, message
);
1218 throw_error (ex
.error
, "%s", message
);
1221 /* The ptrace base target adds the main thread with (pid,0,0)
1222 format. Decorate it with lwp info. */
1223 ptid
= ptid_build (ptid_get_pid (inferior_ptid
),
1224 ptid_get_pid (inferior_ptid
),
1226 thread_change_ptid (inferior_ptid
, ptid
);
1228 /* Add the initial process as the first LWP to the list. */
1229 lp
= add_initial_lwp (ptid
);
1231 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1233 if (!WIFSTOPPED (status
))
1235 if (WIFEXITED (status
))
1237 int exit_code
= WEXITSTATUS (status
);
1239 target_terminal_ours ();
1240 target_mourn_inferior ();
1242 error (_("Unable to attach: program exited normally."));
1244 error (_("Unable to attach: program exited with code %d."),
1247 else if (WIFSIGNALED (status
))
1249 enum gdb_signal signo
;
1251 target_terminal_ours ();
1252 target_mourn_inferior ();
1254 signo
= gdb_signal_from_host (WTERMSIG (status
));
1255 error (_("Unable to attach: program terminated with signal "
1257 gdb_signal_to_name (signo
),
1258 gdb_signal_to_string (signo
));
1261 internal_error (__FILE__
, __LINE__
,
1262 _("unexpected status %d for PID %ld"),
1263 status
, (long) ptid_get_lwp (ptid
));
1268 /* Save the wait status to report later. */
1270 if (debug_linux_nat
)
1271 fprintf_unfiltered (gdb_stdlog
,
1272 "LNA: waitpid %ld, saving status %s\n",
1273 (long) ptid_get_pid (lp
->ptid
), status_to_str (status
));
1275 lp
->status
= status
;
1277 /* We must attach to every LWP. If /proc is mounted, use that to
1278 find them now. The inferior may be using raw clone instead of
1279 using pthreads. But even if it is using pthreads, thread_db
1280 walks structures in the inferior's address space to find the list
1281 of threads/LWPs, and those structures may well be corrupted.
1282 Note that once thread_db is loaded, we'll still use it to list
1283 threads and associate pthread info with each LWP. */
1284 linux_proc_attach_tgid_threads (ptid_get_pid (lp
->ptid
),
1285 attach_proc_task_lwp_callback
);
1287 if (target_can_async_p ())
1288 target_async (inferior_event_handler
, 0);
1291 /* Get pending status of LP. */
1293 get_pending_status (struct lwp_info
*lp
, int *status
)
1295 enum gdb_signal signo
= GDB_SIGNAL_0
;
1297 /* If we paused threads momentarily, we may have stored pending
1298 events in lp->status or lp->waitstatus (see stop_wait_callback),
1299 and GDB core hasn't seen any signal for those threads.
1300 Otherwise, the last signal reported to the core is found in the
1301 thread object's stop_signal.
1303 There's a corner case that isn't handled here at present. Only
1304 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1305 stop_signal make sense as a real signal to pass to the inferior.
1306 Some catchpoint related events, like
1307 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1308 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1309 those traps are debug API (ptrace in our case) related and
1310 induced; the inferior wouldn't see them if it wasn't being
1311 traced. Hence, we should never pass them to the inferior, even
1312 when set to pass state. Since this corner case isn't handled by
1313 infrun.c when proceeding with a signal, for consistency, neither
1314 do we handle it here (or elsewhere in the file we check for
1315 signal pass state). Normally SIGTRAP isn't set to pass state, so
1316 this is really a corner case. */
1318 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1319 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1320 else if (lp
->status
)
1321 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1322 else if (non_stop
&& !is_executing (lp
->ptid
))
1324 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1326 signo
= tp
->suspend
.stop_signal
;
1330 struct target_waitstatus last
;
1333 get_last_target_status (&last_ptid
, &last
);
1335 if (ptid_get_lwp (lp
->ptid
) == ptid_get_lwp (last_ptid
))
1337 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1339 signo
= tp
->suspend
.stop_signal
;
1345 if (signo
== GDB_SIGNAL_0
)
1347 if (debug_linux_nat
)
1348 fprintf_unfiltered (gdb_stdlog
,
1349 "GPT: lwp %s has no pending signal\n",
1350 target_pid_to_str (lp
->ptid
));
1352 else if (!signal_pass_state (signo
))
1354 if (debug_linux_nat
)
1355 fprintf_unfiltered (gdb_stdlog
,
1356 "GPT: lwp %s had signal %s, "
1357 "but it is in no pass state\n",
1358 target_pid_to_str (lp
->ptid
),
1359 gdb_signal_to_string (signo
));
1363 *status
= W_STOPCODE (gdb_signal_to_host (signo
));
1365 if (debug_linux_nat
)
1366 fprintf_unfiltered (gdb_stdlog
,
1367 "GPT: lwp %s has pending signal %s\n",
1368 target_pid_to_str (lp
->ptid
),
1369 gdb_signal_to_string (signo
));
1376 detach_callback (struct lwp_info
*lp
, void *data
)
1378 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1380 if (debug_linux_nat
&& lp
->status
)
1381 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1382 strsignal (WSTOPSIG (lp
->status
)),
1383 target_pid_to_str (lp
->ptid
));
1385 /* If there is a pending SIGSTOP, get rid of it. */
1388 if (debug_linux_nat
)
1389 fprintf_unfiltered (gdb_stdlog
,
1390 "DC: Sending SIGCONT to %s\n",
1391 target_pid_to_str (lp
->ptid
));
1393 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGCONT
);
1397 /* We don't actually detach from the LWP that has an id equal to the
1398 overall process id just yet. */
1399 if (ptid_get_lwp (lp
->ptid
) != ptid_get_pid (lp
->ptid
))
1403 /* Pass on any pending signal for this LWP. */
1404 get_pending_status (lp
, &status
);
1406 if (linux_nat_prepare_to_resume
!= NULL
)
1407 linux_nat_prepare_to_resume (lp
);
1409 if (ptrace (PTRACE_DETACH
, ptid_get_lwp (lp
->ptid
), 0,
1410 WSTOPSIG (status
)) < 0)
1411 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1412 safe_strerror (errno
));
1414 if (debug_linux_nat
)
1415 fprintf_unfiltered (gdb_stdlog
,
1416 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1417 target_pid_to_str (lp
->ptid
),
1418 strsignal (WSTOPSIG (status
)));
1420 delete_lwp (lp
->ptid
);
1427 linux_nat_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1431 struct lwp_info
*main_lwp
;
1433 pid
= ptid_get_pid (inferior_ptid
);
1435 /* Don't unregister from the event loop, as there may be other
1436 inferiors running. */
1438 /* Stop all threads before detaching. ptrace requires that the
1439 thread is stopped to sucessfully detach. */
1440 iterate_over_lwps (pid_to_ptid (pid
), stop_callback
, NULL
);
1441 /* ... and wait until all of them have reported back that
1442 they're no longer running. */
1443 iterate_over_lwps (pid_to_ptid (pid
), stop_wait_callback
, NULL
);
1445 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1447 /* Only the initial process should be left right now. */
1448 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid
)) == 1);
1450 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
1452 /* Pass on any pending signal for the last LWP. */
1453 if ((args
== NULL
|| *args
== '\0')
1454 && get_pending_status (main_lwp
, &status
) != -1
1455 && WIFSTOPPED (status
))
1459 /* Put the signal number in ARGS so that inf_ptrace_detach will
1460 pass it along with PTRACE_DETACH. */
1462 xsnprintf (tem
, 8, "%d", (int) WSTOPSIG (status
));
1464 if (debug_linux_nat
)
1465 fprintf_unfiltered (gdb_stdlog
,
1466 "LND: Sending signal %s to %s\n",
1468 target_pid_to_str (main_lwp
->ptid
));
1471 if (linux_nat_prepare_to_resume
!= NULL
)
1472 linux_nat_prepare_to_resume (main_lwp
);
1473 delete_lwp (main_lwp
->ptid
);
1475 if (forks_exist_p ())
1477 /* Multi-fork case. The current inferior_ptid is being detached
1478 from, but there are other viable forks to debug. Detach from
1479 the current fork, and context-switch to the first
1481 linux_fork_detach (args
, from_tty
);
1484 linux_ops
->to_detach (ops
, args
, from_tty
);
1487 /* Resume execution of the inferior process. If STEP is nonzero,
1488 single-step it. If SIGNAL is nonzero, give it that signal. */
1491 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1497 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1498 We only presently need that if the LWP is stepped though (to
1499 handle the case of stepping a breakpoint instruction). */
1502 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
1504 lp
->stop_pc
= regcache_read_pc (regcache
);
1509 if (linux_nat_prepare_to_resume
!= NULL
)
1510 linux_nat_prepare_to_resume (lp
);
1511 /* Convert to something the lower layer understands. */
1512 ptid
= pid_to_ptid (ptid_get_lwp (lp
->ptid
));
1513 linux_ops
->to_resume (linux_ops
, ptid
, step
, signo
);
1514 lp
->stop_reason
= LWP_STOPPED_BY_NO_REASON
;
1516 registers_changed_ptid (lp
->ptid
);
1522 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1526 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
1528 if (inf
->vfork_child
!= NULL
)
1530 if (debug_linux_nat
)
1531 fprintf_unfiltered (gdb_stdlog
,
1532 "RC: Not resuming %s (vfork parent)\n",
1533 target_pid_to_str (lp
->ptid
));
1535 else if (!lwp_status_pending_p (lp
))
1537 if (debug_linux_nat
)
1538 fprintf_unfiltered (gdb_stdlog
,
1539 "RC: Resuming sibling %s, %s, %s\n",
1540 target_pid_to_str (lp
->ptid
),
1541 (signo
!= GDB_SIGNAL_0
1542 ? strsignal (gdb_signal_to_host (signo
))
1544 step
? "step" : "resume");
1546 linux_resume_one_lwp (lp
, step
, signo
);
1550 if (debug_linux_nat
)
1551 fprintf_unfiltered (gdb_stdlog
,
1552 "RC: Not resuming sibling %s (has pending)\n",
1553 target_pid_to_str (lp
->ptid
));
1558 if (debug_linux_nat
)
1559 fprintf_unfiltered (gdb_stdlog
,
1560 "RC: Not resuming sibling %s (not stopped)\n",
1561 target_pid_to_str (lp
->ptid
));
1565 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1566 Resume LWP with the last stop signal, if it is in pass state. */
1569 linux_nat_resume_callback (struct lwp_info
*lp
, void *except
)
1571 enum gdb_signal signo
= GDB_SIGNAL_0
;
1578 struct thread_info
*thread
;
1580 thread
= find_thread_ptid (lp
->ptid
);
1583 signo
= thread
->suspend
.stop_signal
;
1584 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1588 resume_lwp (lp
, 0, signo
);
1593 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1596 lp
->last_resume_kind
= resume_stop
;
1601 resume_set_callback (struct lwp_info
*lp
, void *data
)
1604 lp
->last_resume_kind
= resume_continue
;
1609 linux_nat_resume (struct target_ops
*ops
,
1610 ptid_t ptid
, int step
, enum gdb_signal signo
)
1612 struct lwp_info
*lp
;
1615 if (debug_linux_nat
)
1616 fprintf_unfiltered (gdb_stdlog
,
1617 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1618 step
? "step" : "resume",
1619 target_pid_to_str (ptid
),
1620 (signo
!= GDB_SIGNAL_0
1621 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1622 target_pid_to_str (inferior_ptid
));
1624 /* A specific PTID means `step only this process id'. */
1625 resume_many
= (ptid_equal (minus_one_ptid
, ptid
)
1626 || ptid_is_pid (ptid
));
1628 /* Mark the lwps we're resuming as resumed. */
1629 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1631 /* See if it's the current inferior that should be handled
1634 lp
= find_lwp_pid (inferior_ptid
);
1636 lp
= find_lwp_pid (ptid
);
1637 gdb_assert (lp
!= NULL
);
1639 /* Remember if we're stepping. */
1640 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1642 /* If we have a pending wait status for this thread, there is no
1643 point in resuming the process. But first make sure that
1644 linux_nat_wait won't preemptively handle the event - we
1645 should never take this short-circuit if we are going to
1646 leave LP running, since we have skipped resuming all the
1647 other threads. This bit of code needs to be synchronized
1648 with linux_nat_wait. */
1650 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1653 && WSTOPSIG (lp
->status
)
1654 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1656 if (debug_linux_nat
)
1657 fprintf_unfiltered (gdb_stdlog
,
1658 "LLR: Not short circuiting for ignored "
1659 "status 0x%x\n", lp
->status
);
1661 /* FIXME: What should we do if we are supposed to continue
1662 this thread with a signal? */
1663 gdb_assert (signo
== GDB_SIGNAL_0
);
1664 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1669 if (lwp_status_pending_p (lp
))
1671 /* FIXME: What should we do if we are supposed to continue
1672 this thread with a signal? */
1673 gdb_assert (signo
== GDB_SIGNAL_0
);
1675 if (debug_linux_nat
)
1676 fprintf_unfiltered (gdb_stdlog
,
1677 "LLR: Short circuiting for status 0x%x\n",
1680 if (target_can_async_p ())
1682 target_async (inferior_event_handler
, 0);
1683 /* Tell the event loop we have something to process. */
1690 iterate_over_lwps (ptid
, linux_nat_resume_callback
, lp
);
1692 linux_resume_one_lwp (lp
, step
, signo
);
1694 if (debug_linux_nat
)
1695 fprintf_unfiltered (gdb_stdlog
,
1696 "LLR: %s %s, %s (resume event thread)\n",
1697 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1698 target_pid_to_str (ptid
),
1699 (signo
!= GDB_SIGNAL_0
1700 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1702 if (target_can_async_p ())
1703 target_async (inferior_event_handler
, 0);
1706 /* Send a signal to an LWP. */
1709 kill_lwp (int lwpid
, int signo
)
1711 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1712 fails, then we are not using nptl threads and we should be using kill. */
1714 #ifdef HAVE_TKILL_SYSCALL
1716 static int tkill_failed
;
1723 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1724 if (errno
!= ENOSYS
)
1731 return kill (lwpid
, signo
);
1734 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1735 event, check if the core is interested in it: if not, ignore the
1736 event, and keep waiting; otherwise, we need to toggle the LWP's
1737 syscall entry/exit status, since the ptrace event itself doesn't
1738 indicate it, and report the trap to higher layers. */
1741 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1743 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1744 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1745 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, lp
->ptid
);
1749 /* If we're stopping threads, there's a SIGSTOP pending, which
1750 makes it so that the LWP reports an immediate syscall return,
1751 followed by the SIGSTOP. Skip seeing that "return" using
1752 PTRACE_CONT directly, and let stop_wait_callback collect the
1753 SIGSTOP. Later when the thread is resumed, a new syscall
1754 entry event. If we didn't do this (and returned 0), we'd
1755 leave a syscall entry pending, and our caller, by using
1756 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1757 itself. Later, when the user re-resumes this LWP, we'd see
1758 another syscall entry event and we'd mistake it for a return.
1760 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1761 (leaving immediately with LWP->signalled set, without issuing
1762 a PTRACE_CONT), it would still be problematic to leave this
1763 syscall enter pending, as later when the thread is resumed,
1764 it would then see the same syscall exit mentioned above,
1765 followed by the delayed SIGSTOP, while the syscall didn't
1766 actually get to execute. It seems it would be even more
1767 confusing to the user. */
1769 if (debug_linux_nat
)
1770 fprintf_unfiltered (gdb_stdlog
,
1771 "LHST: ignoring syscall %d "
1772 "for LWP %ld (stopping threads), "
1773 "resuming with PTRACE_CONT for SIGSTOP\n",
1775 ptid_get_lwp (lp
->ptid
));
1777 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1778 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
1783 if (catch_syscall_enabled ())
1785 /* Always update the entry/return state, even if this particular
1786 syscall isn't interesting to the core now. In async mode,
1787 the user could install a new catchpoint for this syscall
1788 between syscall enter/return, and we'll need to know to
1789 report a syscall return if that happens. */
1790 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1791 ? TARGET_WAITKIND_SYSCALL_RETURN
1792 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1794 if (catching_syscall_number (syscall_number
))
1796 /* Alright, an event to report. */
1797 ourstatus
->kind
= lp
->syscall_state
;
1798 ourstatus
->value
.syscall_number
= syscall_number
;
1800 if (debug_linux_nat
)
1801 fprintf_unfiltered (gdb_stdlog
,
1802 "LHST: stopping for %s of syscall %d"
1805 == TARGET_WAITKIND_SYSCALL_ENTRY
1806 ? "entry" : "return",
1808 ptid_get_lwp (lp
->ptid
));
1812 if (debug_linux_nat
)
1813 fprintf_unfiltered (gdb_stdlog
,
1814 "LHST: ignoring %s of syscall %d "
1816 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1817 ? "entry" : "return",
1819 ptid_get_lwp (lp
->ptid
));
1823 /* If we had been syscall tracing, and hence used PT_SYSCALL
1824 before on this LWP, it could happen that the user removes all
1825 syscall catchpoints before we get to process this event.
1826 There are two noteworthy issues here:
1828 - When stopped at a syscall entry event, resuming with
1829 PT_STEP still resumes executing the syscall and reports a
1832 - Only PT_SYSCALL catches syscall enters. If we last
1833 single-stepped this thread, then this event can't be a
1834 syscall enter. If we last single-stepped this thread, this
1835 has to be a syscall exit.
1837 The points above mean that the next resume, be it PT_STEP or
1838 PT_CONTINUE, can not trigger a syscall trace event. */
1839 if (debug_linux_nat
)
1840 fprintf_unfiltered (gdb_stdlog
,
1841 "LHST: caught syscall event "
1842 "with no syscall catchpoints."
1843 " %d for LWP %ld, ignoring\n",
1845 ptid_get_lwp (lp
->ptid
));
1846 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1849 /* The core isn't interested in this event. For efficiency, avoid
1850 stopping all threads only to have the core resume them all again.
1851 Since we're not stopping threads, if we're still syscall tracing
1852 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1853 subsequent syscall. Simply resume using the inf-ptrace layer,
1854 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1856 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1860 /* Handle a GNU/Linux extended wait response. If we see a clone
1861 event, we need to add the new LWP to our list (and not report the
1862 trap to higher layers). This function returns non-zero if the
1863 event should be ignored and we should wait again. If STOPPING is
1864 true, the new LWP remains stopped, otherwise it is continued. */
1867 linux_handle_extended_wait (struct lwp_info
*lp
, int status
,
1870 int pid
= ptid_get_lwp (lp
->ptid
);
1871 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1872 int event
= linux_ptrace_get_extended_event (status
);
1874 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1875 || event
== PTRACE_EVENT_CLONE
)
1877 unsigned long new_pid
;
1880 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1882 /* If we haven't already seen the new PID stop, wait for it now. */
1883 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1885 /* The new child has a pending SIGSTOP. We can't affect it until it
1886 hits the SIGSTOP, but we're already attached. */
1887 ret
= my_waitpid (new_pid
, &status
,
1888 (event
== PTRACE_EVENT_CLONE
) ? __WCLONE
: 0);
1890 perror_with_name (_("waiting for new child"));
1891 else if (ret
!= new_pid
)
1892 internal_error (__FILE__
, __LINE__
,
1893 _("wait returned unexpected PID %d"), ret
);
1894 else if (!WIFSTOPPED (status
))
1895 internal_error (__FILE__
, __LINE__
,
1896 _("wait returned unexpected status 0x%x"), status
);
1899 ourstatus
->value
.related_pid
= ptid_build (new_pid
, new_pid
, 0);
1901 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1903 /* The arch-specific native code may need to know about new
1904 forks even if those end up never mapped to an
1906 if (linux_nat_new_fork
!= NULL
)
1907 linux_nat_new_fork (lp
, new_pid
);
1910 if (event
== PTRACE_EVENT_FORK
1911 && linux_fork_checkpointing_p (ptid_get_pid (lp
->ptid
)))
1913 /* Handle checkpointing by linux-fork.c here as a special
1914 case. We don't want the follow-fork-mode or 'catch fork'
1915 to interfere with this. */
1917 /* This won't actually modify the breakpoint list, but will
1918 physically remove the breakpoints from the child. */
1919 detach_breakpoints (ptid_build (new_pid
, new_pid
, 0));
1921 /* Retain child fork in ptrace (stopped) state. */
1922 if (!find_fork_pid (new_pid
))
1925 /* Report as spurious, so that infrun doesn't want to follow
1926 this fork. We're actually doing an infcall in
1928 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
1930 /* Report the stop to the core. */
1934 if (event
== PTRACE_EVENT_FORK
)
1935 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
1936 else if (event
== PTRACE_EVENT_VFORK
)
1937 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
1940 struct lwp_info
*new_lp
;
1942 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
1944 if (debug_linux_nat
)
1945 fprintf_unfiltered (gdb_stdlog
,
1946 "LHEW: Got clone event "
1947 "from LWP %d, new child is LWP %ld\n",
1950 new_lp
= add_lwp (ptid_build (ptid_get_pid (lp
->ptid
), new_pid
, 0));
1952 new_lp
->stopped
= 1;
1954 if (WSTOPSIG (status
) != SIGSTOP
)
1956 /* This can happen if someone starts sending signals to
1957 the new thread before it gets a chance to run, which
1958 have a lower number than SIGSTOP (e.g. SIGUSR1).
1959 This is an unlikely case, and harder to handle for
1960 fork / vfork than for clone, so we do not try - but
1961 we handle it for clone events here. We'll send
1962 the other signal on to the thread below. */
1964 new_lp
->signalled
= 1;
1968 struct thread_info
*tp
;
1970 /* When we stop for an event in some other thread, and
1971 pull the thread list just as this thread has cloned,
1972 we'll have seen the new thread in the thread_db list
1973 before handling the CLONE event (glibc's
1974 pthread_create adds the new thread to the thread list
1975 before clone'ing, and has the kernel fill in the
1976 thread's tid on the clone call with
1977 CLONE_PARENT_SETTID). If that happened, and the core
1978 had requested the new thread to stop, we'll have
1979 killed it with SIGSTOP. But since SIGSTOP is not an
1980 RT signal, it can only be queued once. We need to be
1981 careful to not resume the LWP if we wanted it to
1982 stop. In that case, we'll leave the SIGSTOP pending.
1983 It will later be reported as GDB_SIGNAL_0. */
1984 tp
= find_thread_ptid (new_lp
->ptid
);
1985 if (tp
!= NULL
&& tp
->stop_requested
)
1986 new_lp
->last_resume_kind
= resume_stop
;
1993 /* Add the new thread to GDB's lists as soon as possible
1996 1) the frontend doesn't have to wait for a stop to
1999 2) we tag it with the correct running state. */
2001 /* If the thread_db layer is active, let it know about
2002 this new thread, and add it to GDB's list. */
2003 if (!thread_db_attach_lwp (new_lp
->ptid
))
2005 /* We're not using thread_db. Add it to GDB's
2007 target_post_attach (ptid_get_lwp (new_lp
->ptid
));
2008 add_thread (new_lp
->ptid
);
2013 set_running (new_lp
->ptid
, 1);
2014 set_executing (new_lp
->ptid
, 1);
2015 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2017 new_lp
->last_resume_kind
= resume_continue
;
2023 /* We created NEW_LP so it cannot yet contain STATUS. */
2024 gdb_assert (new_lp
->status
== 0);
2026 /* Save the wait status to report later. */
2027 if (debug_linux_nat
)
2028 fprintf_unfiltered (gdb_stdlog
,
2029 "LHEW: waitpid of new LWP %ld, "
2030 "saving status %s\n",
2031 (long) ptid_get_lwp (new_lp
->ptid
),
2032 status_to_str (status
));
2033 new_lp
->status
= status
;
2036 /* Note the need to use the low target ops to resume, to
2037 handle resuming with PT_SYSCALL if we have syscall
2041 new_lp
->resumed
= 1;
2045 gdb_assert (new_lp
->last_resume_kind
== resume_continue
);
2046 if (debug_linux_nat
)
2047 fprintf_unfiltered (gdb_stdlog
,
2048 "LHEW: resuming new LWP %ld\n",
2049 ptid_get_lwp (new_lp
->ptid
));
2050 linux_resume_one_lwp (new_lp
, 0, GDB_SIGNAL_0
);
2054 if (debug_linux_nat
)
2055 fprintf_unfiltered (gdb_stdlog
,
2056 "LHEW: resuming parent LWP %d\n", pid
);
2057 linux_resume_one_lwp (lp
, 0, GDB_SIGNAL_0
);
2064 if (event
== PTRACE_EVENT_EXEC
)
2066 if (debug_linux_nat
)
2067 fprintf_unfiltered (gdb_stdlog
,
2068 "LHEW: Got exec event from LWP %ld\n",
2069 ptid_get_lwp (lp
->ptid
));
2071 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2072 ourstatus
->value
.execd_pathname
2073 = xstrdup (linux_child_pid_to_exec_file (NULL
, pid
));
2075 /* The thread that execed must have been resumed, but, when a
2076 thread execs, it changes its tid to the tgid, and the old
2077 tgid thread might have not been resumed. */
2082 if (event
== PTRACE_EVENT_VFORK_DONE
)
2084 if (current_inferior ()->waiting_for_vfork_done
)
2086 if (debug_linux_nat
)
2087 fprintf_unfiltered (gdb_stdlog
,
2088 "LHEW: Got expected PTRACE_EVENT_"
2089 "VFORK_DONE from LWP %ld: stopping\n",
2090 ptid_get_lwp (lp
->ptid
));
2092 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2096 if (debug_linux_nat
)
2097 fprintf_unfiltered (gdb_stdlog
,
2098 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2099 "from LWP %ld: resuming\n",
2100 ptid_get_lwp (lp
->ptid
));
2101 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2105 internal_error (__FILE__
, __LINE__
,
2106 _("unknown ptrace event %d"), event
);
2109 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2113 wait_lwp (struct lwp_info
*lp
)
2117 int thread_dead
= 0;
2120 gdb_assert (!lp
->stopped
);
2121 gdb_assert (lp
->status
== 0);
2123 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2124 block_child_signals (&prev_mask
);
2128 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2129 was right and we should just call sigsuspend. */
2131 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, WNOHANG
);
2132 if (pid
== -1 && errno
== ECHILD
)
2133 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, __WCLONE
| WNOHANG
);
2134 if (pid
== -1 && errno
== ECHILD
)
2136 /* The thread has previously exited. We need to delete it
2137 now because, for some vendor 2.4 kernels with NPTL
2138 support backported, there won't be an exit event unless
2139 it is the main thread. 2.6 kernels will report an exit
2140 event for each thread that exits, as expected. */
2142 if (debug_linux_nat
)
2143 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2144 target_pid_to_str (lp
->ptid
));
2149 /* Bugs 10970, 12702.
2150 Thread group leader may have exited in which case we'll lock up in
2151 waitpid if there are other threads, even if they are all zombies too.
2152 Basically, we're not supposed to use waitpid this way.
2153 __WCLONE is not applicable for the leader so we can't use that.
2154 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2155 process; it gets ESRCH both for the zombie and for running processes.
2157 As a workaround, check if we're waiting for the thread group leader and
2158 if it's a zombie, and avoid calling waitpid if it is.
2160 This is racy, what if the tgl becomes a zombie right after we check?
2161 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2162 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2164 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
)
2165 && linux_proc_pid_is_zombie (ptid_get_lwp (lp
->ptid
)))
2168 if (debug_linux_nat
)
2169 fprintf_unfiltered (gdb_stdlog
,
2170 "WL: Thread group leader %s vanished.\n",
2171 target_pid_to_str (lp
->ptid
));
2175 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2176 get invoked despite our caller had them intentionally blocked by
2177 block_child_signals. This is sensitive only to the loop of
2178 linux_nat_wait_1 and there if we get called my_waitpid gets called
2179 again before it gets to sigsuspend so we can safely let the handlers
2180 get executed here. */
2182 if (debug_linux_nat
)
2183 fprintf_unfiltered (gdb_stdlog
, "WL: about to sigsuspend\n");
2184 sigsuspend (&suspend_mask
);
2187 restore_child_signals_mask (&prev_mask
);
2191 gdb_assert (pid
== ptid_get_lwp (lp
->ptid
));
2193 if (debug_linux_nat
)
2195 fprintf_unfiltered (gdb_stdlog
,
2196 "WL: waitpid %s received %s\n",
2197 target_pid_to_str (lp
->ptid
),
2198 status_to_str (status
));
2201 /* Check if the thread has exited. */
2202 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2205 if (debug_linux_nat
)
2206 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2207 target_pid_to_str (lp
->ptid
));
2217 gdb_assert (WIFSTOPPED (status
));
2220 if (lp
->must_set_ptrace_flags
)
2222 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2224 linux_enable_event_reporting (ptid_get_lwp (lp
->ptid
), inf
->attach_flag
);
2225 lp
->must_set_ptrace_flags
= 0;
2228 /* Handle GNU/Linux's syscall SIGTRAPs. */
2229 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2231 /* No longer need the sysgood bit. The ptrace event ends up
2232 recorded in lp->waitstatus if we care for it. We can carry
2233 on handling the event like a regular SIGTRAP from here
2235 status
= W_STOPCODE (SIGTRAP
);
2236 if (linux_handle_syscall_trap (lp
, 1))
2237 return wait_lwp (lp
);
2240 /* Handle GNU/Linux's extended waitstatus for trace events. */
2241 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2242 && linux_is_extended_waitstatus (status
))
2244 if (debug_linux_nat
)
2245 fprintf_unfiltered (gdb_stdlog
,
2246 "WL: Handling extended status 0x%06x\n",
2248 if (linux_handle_extended_wait (lp
, status
, 1))
2249 return wait_lwp (lp
);
2255 /* Send a SIGSTOP to LP. */
2258 stop_callback (struct lwp_info
*lp
, void *data
)
2260 if (!lp
->stopped
&& !lp
->signalled
)
2264 if (debug_linux_nat
)
2266 fprintf_unfiltered (gdb_stdlog
,
2267 "SC: kill %s **<SIGSTOP>**\n",
2268 target_pid_to_str (lp
->ptid
));
2271 ret
= kill_lwp (ptid_get_lwp (lp
->ptid
), SIGSTOP
);
2272 if (debug_linux_nat
)
2274 fprintf_unfiltered (gdb_stdlog
,
2275 "SC: lwp kill %d %s\n",
2277 errno
? safe_strerror (errno
) : "ERRNO-OK");
2281 gdb_assert (lp
->status
== 0);
2287 /* Request a stop on LWP. */
2290 linux_stop_lwp (struct lwp_info
*lwp
)
2292 stop_callback (lwp
, NULL
);
2295 /* Return non-zero if LWP PID has a pending SIGINT. */
2298 linux_nat_has_pending_sigint (int pid
)
2300 sigset_t pending
, blocked
, ignored
;
2302 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2304 if (sigismember (&pending
, SIGINT
)
2305 && !sigismember (&ignored
, SIGINT
))
2311 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2314 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2316 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2317 flag to consume the next one. */
2318 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2319 && WSTOPSIG (lp
->status
) == SIGINT
)
2322 lp
->ignore_sigint
= 1;
2327 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2328 This function is called after we know the LWP has stopped; if the LWP
2329 stopped before the expected SIGINT was delivered, then it will never have
2330 arrived. Also, if the signal was delivered to a shared queue and consumed
2331 by a different thread, it will never be delivered to this LWP. */
2334 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2336 if (!lp
->ignore_sigint
)
2339 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp
->ptid
)))
2341 if (debug_linux_nat
)
2342 fprintf_unfiltered (gdb_stdlog
,
2343 "MCIS: Clearing bogus flag for %s\n",
2344 target_pid_to_str (lp
->ptid
));
2345 lp
->ignore_sigint
= 0;
2349 /* Fetch the possible triggered data watchpoint info and store it in
2352 On some archs, like x86, that use debug registers to set
2353 watchpoints, it's possible that the way to know which watched
2354 address trapped, is to check the register that is used to select
2355 which address to watch. Problem is, between setting the watchpoint
2356 and reading back which data address trapped, the user may change
2357 the set of watchpoints, and, as a consequence, GDB changes the
2358 debug registers in the inferior. To avoid reading back a stale
2359 stopped-data-address when that happens, we cache in LP the fact
2360 that a watchpoint trapped, and the corresponding data address, as
2361 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2362 registers meanwhile, we have the cached data we can rely on. */
2365 check_stopped_by_watchpoint (struct lwp_info
*lp
)
2367 struct cleanup
*old_chain
;
2369 if (linux_ops
->to_stopped_by_watchpoint
== NULL
)
2372 old_chain
= save_inferior_ptid ();
2373 inferior_ptid
= lp
->ptid
;
2375 if (linux_ops
->to_stopped_by_watchpoint (linux_ops
))
2377 lp
->stop_reason
= LWP_STOPPED_BY_WATCHPOINT
;
2379 if (linux_ops
->to_stopped_data_address
!= NULL
)
2380 lp
->stopped_data_address_p
=
2381 linux_ops
->to_stopped_data_address (¤t_target
,
2382 &lp
->stopped_data_address
);
2384 lp
->stopped_data_address_p
= 0;
2387 do_cleanups (old_chain
);
2389 return lp
->stop_reason
== LWP_STOPPED_BY_WATCHPOINT
;
2392 /* Called when the LWP stopped for a trap that could be explained by a
2393 watchpoint or a breakpoint. */
2396 save_sigtrap (struct lwp_info
*lp
)
2398 gdb_assert (lp
->stop_reason
== LWP_STOPPED_BY_NO_REASON
);
2399 gdb_assert (lp
->status
!= 0);
2401 if (check_stopped_by_watchpoint (lp
))
2404 if (linux_nat_status_is_event (lp
->status
))
2405 check_stopped_by_breakpoint (lp
);
2408 /* Returns true if the LWP had stopped for a watchpoint. */
2411 linux_nat_stopped_by_watchpoint (struct target_ops
*ops
)
2413 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2415 gdb_assert (lp
!= NULL
);
2417 return lp
->stop_reason
== LWP_STOPPED_BY_WATCHPOINT
;
2421 linux_nat_stopped_data_address (struct target_ops
*ops
, CORE_ADDR
*addr_p
)
2423 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2425 gdb_assert (lp
!= NULL
);
2427 *addr_p
= lp
->stopped_data_address
;
2429 return lp
->stopped_data_address_p
;
2432 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2435 sigtrap_is_event (int status
)
2437 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2440 /* Set alternative SIGTRAP-like events recognizer. If
2441 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2445 linux_nat_set_status_is_event (struct target_ops
*t
,
2446 int (*status_is_event
) (int status
))
2448 linux_nat_status_is_event
= status_is_event
;
2451 /* Wait until LP is stopped. */
2454 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2456 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
2458 /* If this is a vfork parent, bail out, it is not going to report
2459 any SIGSTOP until the vfork is done with. */
2460 if (inf
->vfork_child
!= NULL
)
2467 status
= wait_lwp (lp
);
2471 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2472 && WSTOPSIG (status
) == SIGINT
)
2474 lp
->ignore_sigint
= 0;
2477 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2479 if (debug_linux_nat
)
2480 fprintf_unfiltered (gdb_stdlog
,
2481 "PTRACE_CONT %s, 0, 0 (%s) "
2482 "(discarding SIGINT)\n",
2483 target_pid_to_str (lp
->ptid
),
2484 errno
? safe_strerror (errno
) : "OK");
2486 return stop_wait_callback (lp
, NULL
);
2489 maybe_clear_ignore_sigint (lp
);
2491 if (WSTOPSIG (status
) != SIGSTOP
)
2493 /* The thread was stopped with a signal other than SIGSTOP. */
2495 if (debug_linux_nat
)
2496 fprintf_unfiltered (gdb_stdlog
,
2497 "SWC: Pending event %s in %s\n",
2498 status_to_str ((int) status
),
2499 target_pid_to_str (lp
->ptid
));
2501 /* Save the sigtrap event. */
2502 lp
->status
= status
;
2503 gdb_assert (lp
->signalled
);
2508 /* We caught the SIGSTOP that we intended to catch, so
2509 there's no SIGSTOP pending. */
2511 if (debug_linux_nat
)
2512 fprintf_unfiltered (gdb_stdlog
,
2513 "SWC: Delayed SIGSTOP caught for %s.\n",
2514 target_pid_to_str (lp
->ptid
));
2516 /* Reset SIGNALLED only after the stop_wait_callback call
2517 above as it does gdb_assert on SIGNALLED. */
2525 /* Return non-zero if LP has a wait status pending. Discard the
2526 pending event and resume the LWP if the event that originally
2527 caused the stop became uninteresting. */
2530 status_callback (struct lwp_info
*lp
, void *data
)
2532 /* Only report a pending wait status if we pretend that this has
2533 indeed been resumed. */
2537 if (lp
->stop_reason
== LWP_STOPPED_BY_SW_BREAKPOINT
2538 || lp
->stop_reason
== LWP_STOPPED_BY_HW_BREAKPOINT
)
2540 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2541 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2545 gdb_assert (lp
->status
!= 0);
2547 pc
= regcache_read_pc (regcache
);
2549 if (pc
!= lp
->stop_pc
)
2551 if (debug_linux_nat
)
2552 fprintf_unfiltered (gdb_stdlog
,
2553 "SC: PC of %s changed. was=%s, now=%s\n",
2554 target_pid_to_str (lp
->ptid
),
2555 paddress (target_gdbarch (), lp
->stop_pc
),
2556 paddress (target_gdbarch (), pc
));
2559 else if (!breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2561 if (debug_linux_nat
)
2562 fprintf_unfiltered (gdb_stdlog
,
2563 "SC: previous breakpoint of %s, at %s gone\n",
2564 target_pid_to_str (lp
->ptid
),
2565 paddress (target_gdbarch (), lp
->stop_pc
));
2572 if (debug_linux_nat
)
2573 fprintf_unfiltered (gdb_stdlog
,
2574 "SC: pending event of %s cancelled.\n",
2575 target_pid_to_str (lp
->ptid
));
2578 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2584 return lwp_status_pending_p (lp
);
2587 /* Return non-zero if LP isn't stopped. */
2590 running_callback (struct lwp_info
*lp
, void *data
)
2592 return (!lp
->stopped
2593 || (lwp_status_pending_p (lp
) && lp
->resumed
));
2596 /* Count the LWP's that have had events. */
2599 count_events_callback (struct lwp_info
*lp
, void *data
)
2603 gdb_assert (count
!= NULL
);
2605 /* Select only resumed LWPs that have an event pending. */
2606 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2612 /* Select the LWP (if any) that is currently being single-stepped. */
2615 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2617 if (lp
->last_resume_kind
== resume_step
2624 /* Returns true if LP has a status pending. */
2627 lwp_status_pending_p (struct lwp_info
*lp
)
2629 /* We check for lp->waitstatus in addition to lp->status, because we
2630 can have pending process exits recorded in lp->status and
2631 W_EXITCODE(0,0) happens to be 0. */
2632 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2635 /* Select the Nth LWP that has had a SIGTRAP event. */
2638 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2640 int *selector
= data
;
2642 gdb_assert (selector
!= NULL
);
2644 /* Select only resumed LWPs that have an event pending. */
2645 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2646 if ((*selector
)-- == 0)
2652 /* Called when the LWP got a signal/trap that could be explained by a
2653 software or hardware breakpoint. */
2656 check_stopped_by_breakpoint (struct lwp_info
*lp
)
2658 /* Arrange for a breakpoint to be hit again later. We don't keep
2659 the SIGTRAP status and don't forward the SIGTRAP signal to the
2660 LWP. We will handle the current event, eventually we will resume
2661 this LWP, and this breakpoint will trap again.
2663 If we do not do this, then we run the risk that the user will
2664 delete or disable the breakpoint, but the LWP will have already
2667 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2668 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2672 pc
= regcache_read_pc (regcache
);
2673 sw_bp_pc
= pc
- target_decr_pc_after_break (gdbarch
);
2675 if ((!lp
->step
|| lp
->stop_pc
== sw_bp_pc
)
2676 && software_breakpoint_inserted_here_p (get_regcache_aspace (regcache
),
2679 /* The LWP was either continued, or stepped a software
2680 breakpoint instruction. */
2681 if (debug_linux_nat
)
2682 fprintf_unfiltered (gdb_stdlog
,
2683 "CB: Push back software breakpoint for %s\n",
2684 target_pid_to_str (lp
->ptid
));
2686 /* Back up the PC if necessary. */
2688 regcache_write_pc (regcache
, sw_bp_pc
);
2690 lp
->stop_pc
= sw_bp_pc
;
2691 lp
->stop_reason
= LWP_STOPPED_BY_SW_BREAKPOINT
;
2695 if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2697 if (debug_linux_nat
)
2698 fprintf_unfiltered (gdb_stdlog
,
2699 "CB: Push back hardware breakpoint for %s\n",
2700 target_pid_to_str (lp
->ptid
));
2703 lp
->stop_reason
= LWP_STOPPED_BY_HW_BREAKPOINT
;
2710 /* Select one LWP out of those that have events pending. */
2713 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2716 int random_selector
;
2717 struct lwp_info
*event_lp
= NULL
;
2719 /* Record the wait status for the original LWP. */
2720 (*orig_lp
)->status
= *status
;
2722 /* In all-stop, give preference to the LWP that is being
2723 single-stepped. There will be at most one, and it will be the
2724 LWP that the core is most interested in. If we didn't do this,
2725 then we'd have to handle pending step SIGTRAPs somehow in case
2726 the core later continues the previously-stepped thread, as
2727 otherwise we'd report the pending SIGTRAP then, and the core, not
2728 having stepped the thread, wouldn't understand what the trap was
2729 for, and therefore would report it to the user as a random
2733 event_lp
= iterate_over_lwps (filter
,
2734 select_singlestep_lwp_callback
, NULL
);
2735 if (event_lp
!= NULL
)
2737 if (debug_linux_nat
)
2738 fprintf_unfiltered (gdb_stdlog
,
2739 "SEL: Select single-step %s\n",
2740 target_pid_to_str (event_lp
->ptid
));
2744 if (event_lp
== NULL
)
2746 /* Pick one at random, out of those which have had events. */
2748 /* First see how many events we have. */
2749 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2751 /* Now randomly pick a LWP out of those that have had
2753 random_selector
= (int)
2754 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2756 if (debug_linux_nat
&& num_events
> 1)
2757 fprintf_unfiltered (gdb_stdlog
,
2758 "SEL: Found %d events, selecting #%d\n",
2759 num_events
, random_selector
);
2761 event_lp
= iterate_over_lwps (filter
,
2762 select_event_lwp_callback
,
2766 if (event_lp
!= NULL
)
2768 /* Switch the event LWP. */
2769 *orig_lp
= event_lp
;
2770 *status
= event_lp
->status
;
2773 /* Flush the wait status for the event LWP. */
2774 (*orig_lp
)->status
= 0;
2777 /* Return non-zero if LP has been resumed. */
2780 resumed_callback (struct lwp_info
*lp
, void *data
)
2785 /* Stop an active thread, verify it still exists, then resume it. If
2786 the thread ends up with a pending status, then it is not resumed,
2787 and *DATA (really a pointer to int), is set. */
2790 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2794 ptid_t ptid
= lp
->ptid
;
2796 stop_callback (lp
, NULL
);
2797 stop_wait_callback (lp
, NULL
);
2799 /* Resume if the lwp still exists, and the core wanted it
2801 lp
= find_lwp_pid (ptid
);
2804 if (lp
->last_resume_kind
== resume_stop
2805 && !lwp_status_pending_p (lp
))
2807 /* The core wanted the LWP to stop. Even if it stopped
2808 cleanly (with SIGSTOP), leave the event pending. */
2809 if (debug_linux_nat
)
2810 fprintf_unfiltered (gdb_stdlog
,
2811 "SARC: core wanted LWP %ld stopped "
2812 "(leaving SIGSTOP pending)\n",
2813 ptid_get_lwp (lp
->ptid
));
2814 lp
->status
= W_STOPCODE (SIGSTOP
);
2817 if (!lwp_status_pending_p (lp
))
2819 if (debug_linux_nat
)
2820 fprintf_unfiltered (gdb_stdlog
,
2821 "SARC: re-resuming LWP %ld\n",
2822 ptid_get_lwp (lp
->ptid
));
2823 resume_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2827 if (debug_linux_nat
)
2828 fprintf_unfiltered (gdb_stdlog
,
2829 "SARC: not re-resuming LWP %ld "
2831 ptid_get_lwp (lp
->ptid
));
2838 /* Check if we should go on and pass this event to common code.
2839 Return the affected lwp if we are, or NULL otherwise. */
2841 static struct lwp_info
*
2842 linux_nat_filter_event (int lwpid
, int status
)
2844 struct lwp_info
*lp
;
2845 int event
= linux_ptrace_get_extended_event (status
);
2847 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2849 /* Check for stop events reported by a process we didn't already
2850 know about - anything not already in our LWP list.
2852 If we're expecting to receive stopped processes after
2853 fork, vfork, and clone events, then we'll just add the
2854 new one to our list and go back to waiting for the event
2855 to be reported - the stopped process might be returned
2856 from waitpid before or after the event is.
2858 But note the case of a non-leader thread exec'ing after the
2859 leader having exited, and gone from our lists. The non-leader
2860 thread changes its tid to the tgid. */
2862 if (WIFSTOPPED (status
) && lp
== NULL
2863 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2865 /* A multi-thread exec after we had seen the leader exiting. */
2866 if (debug_linux_nat
)
2867 fprintf_unfiltered (gdb_stdlog
,
2868 "LLW: Re-adding thread group leader LWP %d.\n",
2871 lp
= add_lwp (ptid_build (lwpid
, lwpid
, 0));
2874 add_thread (lp
->ptid
);
2877 if (WIFSTOPPED (status
) && !lp
)
2879 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2883 /* Make sure we don't report an event for the exit of an LWP not in
2884 our list, i.e. not part of the current process. This can happen
2885 if we detach from a program we originally forked and then it
2887 if (!WIFSTOPPED (status
) && !lp
)
2890 /* This LWP is stopped now. (And if dead, this prevents it from
2891 ever being continued.) */
2894 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2896 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2898 linux_enable_event_reporting (ptid_get_lwp (lp
->ptid
), inf
->attach_flag
);
2899 lp
->must_set_ptrace_flags
= 0;
2902 /* Handle GNU/Linux's syscall SIGTRAPs. */
2903 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2905 /* No longer need the sysgood bit. The ptrace event ends up
2906 recorded in lp->waitstatus if we care for it. We can carry
2907 on handling the event like a regular SIGTRAP from here
2909 status
= W_STOPCODE (SIGTRAP
);
2910 if (linux_handle_syscall_trap (lp
, 0))
2914 /* Handle GNU/Linux's extended waitstatus for trace events. */
2915 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2916 && linux_is_extended_waitstatus (status
))
2918 if (debug_linux_nat
)
2919 fprintf_unfiltered (gdb_stdlog
,
2920 "LLW: Handling extended status 0x%06x\n",
2922 if (linux_handle_extended_wait (lp
, status
, 0))
2926 /* Check if the thread has exited. */
2927 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2929 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2931 /* If this is the main thread, we must stop all threads and
2932 verify if they are still alive. This is because in the
2933 nptl thread model on Linux 2.4, there is no signal issued
2934 for exiting LWPs other than the main thread. We only get
2935 the main thread exit signal once all child threads have
2936 already exited. If we stop all the threads and use the
2937 stop_wait_callback to check if they have exited we can
2938 determine whether this signal should be ignored or
2939 whether it means the end of the debugged application,
2940 regardless of which threading model is being used. */
2941 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
))
2943 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
2944 stop_and_resume_callback
, NULL
);
2947 if (debug_linux_nat
)
2948 fprintf_unfiltered (gdb_stdlog
,
2949 "LLW: %s exited.\n",
2950 target_pid_to_str (lp
->ptid
));
2952 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2954 /* If there is at least one more LWP, then the exit signal
2955 was not the end of the debugged application and should be
2962 gdb_assert (lp
->resumed
);
2964 if (debug_linux_nat
)
2965 fprintf_unfiltered (gdb_stdlog
,
2966 "Process %ld exited\n",
2967 ptid_get_lwp (lp
->ptid
));
2969 /* This was the last lwp in the process. Since events are
2970 serialized to GDB core, we may not be able report this one
2971 right now, but GDB core and the other target layers will want
2972 to be notified about the exit code/signal, leave the status
2973 pending for the next time we're able to report it. */
2975 /* Dead LWP's aren't expected to reported a pending sigstop. */
2978 /* Store the pending event in the waitstatus, because
2979 W_EXITCODE(0,0) == 0. */
2980 store_waitstatus (&lp
->waitstatus
, status
);
2984 /* Check if the current LWP has previously exited. In the nptl
2985 thread model, LWPs other than the main thread do not issue
2986 signals when they exit so we must check whenever the thread has
2987 stopped. A similar check is made in stop_wait_callback(). */
2988 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1 && !linux_thread_alive (lp
->ptid
))
2990 ptid_t ptid
= pid_to_ptid (ptid_get_pid (lp
->ptid
));
2992 if (debug_linux_nat
)
2993 fprintf_unfiltered (gdb_stdlog
,
2994 "LLW: %s exited.\n",
2995 target_pid_to_str (lp
->ptid
));
2999 /* Make sure there is at least one thread running. */
3000 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
3002 /* Discard the event. */
3006 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3007 an attempt to stop an LWP. */
3009 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3011 if (debug_linux_nat
)
3012 fprintf_unfiltered (gdb_stdlog
,
3013 "LLW: Delayed SIGSTOP caught for %s.\n",
3014 target_pid_to_str (lp
->ptid
));
3018 if (lp
->last_resume_kind
!= resume_stop
)
3020 /* This is a delayed SIGSTOP. */
3022 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3023 if (debug_linux_nat
)
3024 fprintf_unfiltered (gdb_stdlog
,
3025 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3027 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3028 target_pid_to_str (lp
->ptid
));
3030 gdb_assert (lp
->resumed
);
3032 /* Discard the event. */
3037 /* Make sure we don't report a SIGINT that we have already displayed
3038 for another thread. */
3039 if (lp
->ignore_sigint
3040 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3042 if (debug_linux_nat
)
3043 fprintf_unfiltered (gdb_stdlog
,
3044 "LLW: Delayed SIGINT caught for %s.\n",
3045 target_pid_to_str (lp
->ptid
));
3047 /* This is a delayed SIGINT. */
3048 lp
->ignore_sigint
= 0;
3050 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3051 if (debug_linux_nat
)
3052 fprintf_unfiltered (gdb_stdlog
,
3053 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3055 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3056 target_pid_to_str (lp
->ptid
));
3057 gdb_assert (lp
->resumed
);
3059 /* Discard the event. */
3063 /* Don't report signals that GDB isn't interested in, such as
3064 signals that are neither printed nor stopped upon. Stopping all
3065 threads can be a bit time-consuming so if we want decent
3066 performance with heavily multi-threaded programs, especially when
3067 they're using a high frequency timer, we'd better avoid it if we
3069 if (WIFSTOPPED (status
))
3071 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3075 /* Only do the below in all-stop, as we currently use SIGSTOP
3076 to implement target_stop (see linux_nat_stop) in
3078 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3080 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3081 forwarded to the entire process group, that is, all LWPs
3082 will receive it - unless they're using CLONE_THREAD to
3083 share signals. Since we only want to report it once, we
3084 mark it as ignored for all LWPs except this one. */
3085 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
3086 set_ignore_sigint
, NULL
);
3087 lp
->ignore_sigint
= 0;
3090 maybe_clear_ignore_sigint (lp
);
3093 /* When using hardware single-step, we need to report every signal.
3094 Otherwise, signals in pass_mask may be short-circuited. */
3096 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
)))
3098 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3099 if (debug_linux_nat
)
3100 fprintf_unfiltered (gdb_stdlog
,
3101 "LLW: %s %s, %s (preempt 'handle')\n",
3103 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3104 target_pid_to_str (lp
->ptid
),
3105 (signo
!= GDB_SIGNAL_0
3106 ? strsignal (gdb_signal_to_host (signo
))
3112 /* An interesting event. */
3114 lp
->status
= status
;
3119 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3120 their exits until all other threads in the group have exited. */
3123 check_zombie_leaders (void)
3125 struct inferior
*inf
;
3129 struct lwp_info
*leader_lp
;
3134 leader_lp
= find_lwp_pid (pid_to_ptid (inf
->pid
));
3135 if (leader_lp
!= NULL
3136 /* Check if there are other threads in the group, as we may
3137 have raced with the inferior simply exiting. */
3138 && num_lwps (inf
->pid
) > 1
3139 && linux_proc_pid_is_zombie (inf
->pid
))
3141 if (debug_linux_nat
)
3142 fprintf_unfiltered (gdb_stdlog
,
3143 "CZL: Thread group leader %d zombie "
3144 "(it exited, or another thread execd).\n",
3147 /* A leader zombie can mean one of two things:
3149 - It exited, and there's an exit status pending
3150 available, or only the leader exited (not the whole
3151 program). In the latter case, we can't waitpid the
3152 leader's exit status until all other threads are gone.
3154 - There are 3 or more threads in the group, and a thread
3155 other than the leader exec'd. On an exec, the Linux
3156 kernel destroys all other threads (except the execing
3157 one) in the thread group, and resets the execing thread's
3158 tid to the tgid. No exit notification is sent for the
3159 execing thread -- from the ptracer's perspective, it
3160 appears as though the execing thread just vanishes.
3161 Until we reap all other threads except the leader and the
3162 execing thread, the leader will be zombie, and the
3163 execing thread will be in `D (disc sleep)'. As soon as
3164 all other threads are reaped, the execing thread changes
3165 it's tid to the tgid, and the previous (zombie) leader
3166 vanishes, giving place to the "new" leader. We could try
3167 distinguishing the exit and exec cases, by waiting once
3168 more, and seeing if something comes out, but it doesn't
3169 sound useful. The previous leader _does_ go away, and
3170 we'll re-add the new one once we see the exec event
3171 (which is just the same as what would happen if the
3172 previous leader did exit voluntarily before some other
3175 if (debug_linux_nat
)
3176 fprintf_unfiltered (gdb_stdlog
,
3177 "CZL: Thread group leader %d vanished.\n",
3179 exit_lwp (leader_lp
);
3185 linux_nat_wait_1 (struct target_ops
*ops
,
3186 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3190 enum resume_kind last_resume_kind
;
3191 struct lwp_info
*lp
;
3194 if (debug_linux_nat
)
3195 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3197 /* The first time we get here after starting a new inferior, we may
3198 not have added it to the LWP list yet - this is the earliest
3199 moment at which we know its PID. */
3200 if (ptid_is_pid (inferior_ptid
))
3202 /* Upgrade the main thread's ptid. */
3203 thread_change_ptid (inferior_ptid
,
3204 ptid_build (ptid_get_pid (inferior_ptid
),
3205 ptid_get_pid (inferior_ptid
), 0));
3207 lp
= add_initial_lwp (inferior_ptid
);
3211 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3212 block_child_signals (&prev_mask
);
3214 /* First check if there is a LWP with a wait status pending. */
3215 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3218 if (debug_linux_nat
)
3219 fprintf_unfiltered (gdb_stdlog
,
3220 "LLW: Using pending wait status %s for %s.\n",
3221 status_to_str (lp
->status
),
3222 target_pid_to_str (lp
->ptid
));
3225 if (!target_can_async_p ())
3227 /* Causes SIGINT to be passed on to the attached process. */
3231 /* But if we don't find a pending event, we'll have to wait. Always
3232 pull all events out of the kernel. We'll randomly select an
3233 event LWP out of all that have events, to prevent starvation. */
3239 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3242 - If the thread group leader exits while other threads in the
3243 thread group still exist, waitpid(TGID, ...) hangs. That
3244 waitpid won't return an exit status until the other threads
3245 in the group are reapped.
3247 - When a non-leader thread execs, that thread just vanishes
3248 without reporting an exit (so we'd hang if we waited for it
3249 explicitly in that case). The exec event is reported to
3253 lwpid
= my_waitpid (-1, &status
, __WCLONE
| WNOHANG
);
3254 if (lwpid
== 0 || (lwpid
== -1 && errno
== ECHILD
))
3255 lwpid
= my_waitpid (-1, &status
, WNOHANG
);
3257 if (debug_linux_nat
)
3258 fprintf_unfiltered (gdb_stdlog
,
3259 "LNW: waitpid(-1, ...) returned %d, %s\n",
3260 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3264 if (debug_linux_nat
)
3266 fprintf_unfiltered (gdb_stdlog
,
3267 "LLW: waitpid %ld received %s\n",
3268 (long) lwpid
, status_to_str (status
));
3271 linux_nat_filter_event (lwpid
, status
);
3272 /* Retry until nothing comes out of waitpid. A single
3273 SIGCHLD can indicate more than one child stopped. */
3277 /* Now that we've pulled all events out of the kernel, check if
3278 there's any LWP with a status to report to the core. */
3279 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3283 /* Check for zombie thread group leaders. Those can't be reaped
3284 until all other threads in the thread group are. */
3285 check_zombie_leaders ();
3287 /* If there are no resumed children left, bail. We'd be stuck
3288 forever in the sigsuspend call below otherwise. */
3289 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3291 if (debug_linux_nat
)
3292 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3294 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3296 if (!target_can_async_p ())
3297 clear_sigint_trap ();
3299 restore_child_signals_mask (&prev_mask
);
3300 return minus_one_ptid
;
3303 /* No interesting event to report to the core. */
3305 if (target_options
& TARGET_WNOHANG
)
3307 if (debug_linux_nat
)
3308 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3310 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3311 restore_child_signals_mask (&prev_mask
);
3312 return minus_one_ptid
;
3315 /* We shouldn't end up here unless we want to try again. */
3316 gdb_assert (lp
== NULL
);
3318 /* Block until we get an event reported with SIGCHLD. */
3319 if (debug_linux_nat
)
3320 fprintf_unfiltered (gdb_stdlog
, "LNW: about to sigsuspend\n");
3321 sigsuspend (&suspend_mask
);
3324 if (!target_can_async_p ())
3325 clear_sigint_trap ();
3329 status
= lp
->status
;
3334 /* Now stop all other LWP's ... */
3335 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3337 /* ... and wait until all of them have reported back that
3338 they're no longer running. */
3339 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3342 /* If we're not waiting for a specific LWP, choose an event LWP from
3343 among those that have had events. Giving equal priority to all
3344 LWPs that have had events helps prevent starvation. */
3345 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3346 select_event_lwp (ptid
, &lp
, &status
);
3348 gdb_assert (lp
!= NULL
);
3350 /* Now that we've selected our final event LWP, un-adjust its PC if
3351 it was a software breakpoint. */
3352 if (lp
->stop_reason
== LWP_STOPPED_BY_SW_BREAKPOINT
)
3354 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3355 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3356 int decr_pc
= target_decr_pc_after_break (gdbarch
);
3362 pc
= regcache_read_pc (regcache
);
3363 regcache_write_pc (regcache
, pc
+ decr_pc
);
3367 /* We'll need this to determine whether to report a SIGSTOP as
3368 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3370 last_resume_kind
= lp
->last_resume_kind
;
3374 /* In all-stop, from the core's perspective, all LWPs are now
3375 stopped until a new resume action is sent over. */
3376 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3380 resume_clear_callback (lp
, NULL
);
3383 if (linux_nat_status_is_event (status
))
3385 if (debug_linux_nat
)
3386 fprintf_unfiltered (gdb_stdlog
,
3387 "LLW: trap ptid is %s.\n",
3388 target_pid_to_str (lp
->ptid
));
3391 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3393 *ourstatus
= lp
->waitstatus
;
3394 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3397 store_waitstatus (ourstatus
, status
);
3399 if (debug_linux_nat
)
3400 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3402 restore_child_signals_mask (&prev_mask
);
3404 if (last_resume_kind
== resume_stop
3405 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3406 && WSTOPSIG (status
) == SIGSTOP
)
3408 /* A thread that has been requested to stop by GDB with
3409 target_stop, and it stopped cleanly, so report as SIG0. The
3410 use of SIGSTOP is an implementation detail. */
3411 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3414 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3415 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3418 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3423 /* Resume LWPs that are currently stopped without any pending status
3424 to report, but are resumed from the core's perspective. */
3427 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3429 ptid_t
*wait_ptid_p
= data
;
3433 && !lwp_status_pending_p (lp
))
3435 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3436 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3437 CORE_ADDR pc
= regcache_read_pc (regcache
);
3439 gdb_assert (is_executing (lp
->ptid
));
3441 /* Don't bother if there's a breakpoint at PC that we'd hit
3442 immediately, and we're not waiting for this LWP. */
3443 if (!ptid_match (lp
->ptid
, *wait_ptid_p
))
3445 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
3449 if (debug_linux_nat
)
3450 fprintf_unfiltered (gdb_stdlog
,
3451 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3452 target_pid_to_str (lp
->ptid
),
3453 paddress (gdbarch
, pc
),
3456 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3463 linux_nat_wait (struct target_ops
*ops
,
3464 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3469 if (debug_linux_nat
)
3471 char *options_string
;
3473 options_string
= target_options_to_string (target_options
);
3474 fprintf_unfiltered (gdb_stdlog
,
3475 "linux_nat_wait: [%s], [%s]\n",
3476 target_pid_to_str (ptid
),
3478 xfree (options_string
);
3481 /* Flush the async file first. */
3482 if (target_can_async_p ())
3483 async_file_flush ();
3485 /* Resume LWPs that are currently stopped without any pending status
3486 to report, but are resumed from the core's perspective. LWPs get
3487 in this state if we find them stopping at a time we're not
3488 interested in reporting the event (target_wait on a
3489 specific_process, for example, see linux_nat_wait_1), and
3490 meanwhile the event became uninteresting. Don't bother resuming
3491 LWPs we're not going to wait for if they'd stop immediately. */
3493 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3495 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
3497 /* If we requested any event, and something came out, assume there
3498 may be more. If we requested a specific lwp or process, also
3499 assume there may be more. */
3500 if (target_can_async_p ()
3501 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3502 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3503 || !ptid_equal (ptid
, minus_one_ptid
)))
3506 /* Get ready for the next event. */
3507 if (target_can_async_p ())
3508 target_async (inferior_event_handler
, 0);
3514 kill_callback (struct lwp_info
*lp
, void *data
)
3516 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3519 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGKILL
);
3520 if (debug_linux_nat
)
3522 int save_errno
= errno
;
3524 fprintf_unfiltered (gdb_stdlog
,
3525 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3526 target_pid_to_str (lp
->ptid
),
3527 save_errno
? safe_strerror (save_errno
) : "OK");
3530 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3533 ptrace (PTRACE_KILL
, ptid_get_lwp (lp
->ptid
), 0, 0);
3534 if (debug_linux_nat
)
3536 int save_errno
= errno
;
3538 fprintf_unfiltered (gdb_stdlog
,
3539 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3540 target_pid_to_str (lp
->ptid
),
3541 save_errno
? safe_strerror (save_errno
) : "OK");
3548 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3552 /* We must make sure that there are no pending events (delayed
3553 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3554 program doesn't interfere with any following debugging session. */
3556 /* For cloned processes we must check both with __WCLONE and
3557 without, since the exit status of a cloned process isn't reported
3563 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, __WCLONE
);
3564 if (pid
!= (pid_t
) -1)
3566 if (debug_linux_nat
)
3567 fprintf_unfiltered (gdb_stdlog
,
3568 "KWC: wait %s received unknown.\n",
3569 target_pid_to_str (lp
->ptid
));
3570 /* The Linux kernel sometimes fails to kill a thread
3571 completely after PTRACE_KILL; that goes from the stop
3572 point in do_fork out to the one in
3573 get_signal_to_deliever and waits again. So kill it
3575 kill_callback (lp
, NULL
);
3578 while (pid
== ptid_get_lwp (lp
->ptid
));
3580 gdb_assert (pid
== -1 && errno
== ECHILD
);
3585 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, 0);
3586 if (pid
!= (pid_t
) -1)
3588 if (debug_linux_nat
)
3589 fprintf_unfiltered (gdb_stdlog
,
3590 "KWC: wait %s received unk.\n",
3591 target_pid_to_str (lp
->ptid
));
3592 /* See the call to kill_callback above. */
3593 kill_callback (lp
, NULL
);
3596 while (pid
== ptid_get_lwp (lp
->ptid
));
3598 gdb_assert (pid
== -1 && errno
== ECHILD
);
3603 linux_nat_kill (struct target_ops
*ops
)
3605 struct target_waitstatus last
;
3609 /* If we're stopped while forking and we haven't followed yet,
3610 kill the other task. We need to do this first because the
3611 parent will be sleeping if this is a vfork. */
3613 get_last_target_status (&last_ptid
, &last
);
3615 if (last
.kind
== TARGET_WAITKIND_FORKED
3616 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3618 ptrace (PT_KILL
, ptid_get_pid (last
.value
.related_pid
), 0, 0);
3621 /* Let the arch-specific native code know this process is
3623 linux_nat_forget_process (ptid_get_pid (last
.value
.related_pid
));
3626 if (forks_exist_p ())
3627 linux_fork_killall ();
3630 ptid_t ptid
= pid_to_ptid (ptid_get_pid (inferior_ptid
));
3632 /* Stop all threads before killing them, since ptrace requires
3633 that the thread is stopped to sucessfully PTRACE_KILL. */
3634 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3635 /* ... and wait until all of them have reported back that
3636 they're no longer running. */
3637 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3639 /* Kill all LWP's ... */
3640 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3642 /* ... and wait until we've flushed all events. */
3643 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3646 target_mourn_inferior ();
3650 linux_nat_mourn_inferior (struct target_ops
*ops
)
3652 int pid
= ptid_get_pid (inferior_ptid
);
3654 purge_lwp_list (pid
);
3656 if (! forks_exist_p ())
3657 /* Normal case, no other forks available. */
3658 linux_ops
->to_mourn_inferior (ops
);
3660 /* Multi-fork case. The current inferior_ptid has exited, but
3661 there are other viable forks to debug. Delete the exiting
3662 one and context-switch to the first available. */
3663 linux_fork_mourn_inferior ();
3665 /* Let the arch-specific native code know this process is gone. */
3666 linux_nat_forget_process (pid
);
3669 /* Convert a native/host siginfo object, into/from the siginfo in the
3670 layout of the inferiors' architecture. */
3673 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3677 if (linux_nat_siginfo_fixup
!= NULL
)
3678 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3680 /* If there was no callback, or the callback didn't do anything,
3681 then just do a straight memcpy. */
3685 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3687 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3691 static enum target_xfer_status
3692 linux_xfer_siginfo (struct target_ops
*ops
, enum target_object object
,
3693 const char *annex
, gdb_byte
*readbuf
,
3694 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3695 ULONGEST
*xfered_len
)
3699 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3701 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3702 gdb_assert (readbuf
|| writebuf
);
3704 pid
= ptid_get_lwp (inferior_ptid
);
3706 pid
= ptid_get_pid (inferior_ptid
);
3708 if (offset
> sizeof (siginfo
))
3709 return TARGET_XFER_E_IO
;
3712 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3714 return TARGET_XFER_E_IO
;
3716 /* When GDB is built as a 64-bit application, ptrace writes into
3717 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3718 inferior with a 64-bit GDB should look the same as debugging it
3719 with a 32-bit GDB, we need to convert it. GDB core always sees
3720 the converted layout, so any read/write will have to be done
3722 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3724 if (offset
+ len
> sizeof (siginfo
))
3725 len
= sizeof (siginfo
) - offset
;
3727 if (readbuf
!= NULL
)
3728 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3731 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3733 /* Convert back to ptrace layout before flushing it out. */
3734 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3737 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3739 return TARGET_XFER_E_IO
;
3743 return TARGET_XFER_OK
;
3746 static enum target_xfer_status
3747 linux_nat_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3748 const char *annex
, gdb_byte
*readbuf
,
3749 const gdb_byte
*writebuf
,
3750 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3752 struct cleanup
*old_chain
;
3753 enum target_xfer_status xfer
;
3755 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3756 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3757 offset
, len
, xfered_len
);
3759 /* The target is connected but no live inferior is selected. Pass
3760 this request down to a lower stratum (e.g., the executable
3762 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3763 return TARGET_XFER_EOF
;
3765 old_chain
= save_inferior_ptid ();
3767 if (ptid_lwp_p (inferior_ptid
))
3768 inferior_ptid
= pid_to_ptid (ptid_get_lwp (inferior_ptid
));
3770 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3771 offset
, len
, xfered_len
);
3773 do_cleanups (old_chain
);
3778 linux_thread_alive (ptid_t ptid
)
3782 gdb_assert (ptid_lwp_p (ptid
));
3784 /* Send signal 0 instead of anything ptrace, because ptracing a
3785 running thread errors out claiming that the thread doesn't
3787 err
= kill_lwp (ptid_get_lwp (ptid
), 0);
3789 if (debug_linux_nat
)
3790 fprintf_unfiltered (gdb_stdlog
,
3791 "LLTA: KILL(SIG0) %s (%s)\n",
3792 target_pid_to_str (ptid
),
3793 err
? safe_strerror (tmp_errno
) : "OK");
3802 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3804 return linux_thread_alive (ptid
);
3808 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3810 static char buf
[64];
3812 if (ptid_lwp_p (ptid
)
3813 && (ptid_get_pid (ptid
) != ptid_get_lwp (ptid
)
3814 || num_lwps (ptid_get_pid (ptid
)) > 1))
3816 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid_get_lwp (ptid
));
3820 return normal_pid_to_str (ptid
);
3824 linux_nat_thread_name (struct target_ops
*self
, struct thread_info
*thr
)
3826 int pid
= ptid_get_pid (thr
->ptid
);
3827 long lwp
= ptid_get_lwp (thr
->ptid
);
3828 #define FORMAT "/proc/%d/task/%ld/comm"
3829 char buf
[sizeof (FORMAT
) + 30];
3831 char *result
= NULL
;
3833 snprintf (buf
, sizeof (buf
), FORMAT
, pid
, lwp
);
3834 comm_file
= gdb_fopen_cloexec (buf
, "r");
3837 /* Not exported by the kernel, so we define it here. */
3839 static char line
[COMM_LEN
+ 1];
3841 if (fgets (line
, sizeof (line
), comm_file
))
3843 char *nl
= strchr (line
, '\n');
3860 /* Accepts an integer PID; Returns a string representing a file that
3861 can be opened to get the symbols for the child process. */
3864 linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
)
3866 static char buf
[PATH_MAX
];
3867 char name
[PATH_MAX
];
3869 xsnprintf (name
, PATH_MAX
, "/proc/%d/exe", pid
);
3870 memset (buf
, 0, PATH_MAX
);
3871 if (readlink (name
, buf
, PATH_MAX
- 1) <= 0)
3877 /* Implement the to_xfer_partial interface for memory reads using the /proc
3878 filesystem. Because we can use a single read() call for /proc, this
3879 can be much more efficient than banging away at PTRACE_PEEKTEXT,
3880 but it doesn't support writes. */
3882 static enum target_xfer_status
3883 linux_proc_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3884 const char *annex
, gdb_byte
*readbuf
,
3885 const gdb_byte
*writebuf
,
3886 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3892 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
3895 /* Don't bother for one word. */
3896 if (len
< 3 * sizeof (long))
3897 return TARGET_XFER_EOF
;
3899 /* We could keep this file open and cache it - possibly one per
3900 thread. That requires some juggling, but is even faster. */
3901 xsnprintf (filename
, sizeof filename
, "/proc/%d/mem",
3902 ptid_get_pid (inferior_ptid
));
3903 fd
= gdb_open_cloexec (filename
, O_RDONLY
| O_LARGEFILE
, 0);
3905 return TARGET_XFER_EOF
;
3907 /* If pread64 is available, use it. It's faster if the kernel
3908 supports it (only one syscall), and it's 64-bit safe even on
3909 32-bit platforms (for instance, SPARC debugging a SPARC64
3912 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
3914 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
3923 return TARGET_XFER_EOF
;
3927 return TARGET_XFER_OK
;
3932 /* Enumerate spufs IDs for process PID. */
3934 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
3936 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
3938 LONGEST written
= 0;
3941 struct dirent
*entry
;
3943 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
3944 dir
= opendir (path
);
3949 while ((entry
= readdir (dir
)) != NULL
)
3955 fd
= atoi (entry
->d_name
);
3959 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
3960 if (stat (path
, &st
) != 0)
3962 if (!S_ISDIR (st
.st_mode
))
3965 if (statfs (path
, &stfs
) != 0)
3967 if (stfs
.f_type
!= SPUFS_MAGIC
)
3970 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
3972 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
3982 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
3983 object type, using the /proc file system. */
3985 static enum target_xfer_status
3986 linux_proc_xfer_spu (struct target_ops
*ops
, enum target_object object
,
3987 const char *annex
, gdb_byte
*readbuf
,
3988 const gdb_byte
*writebuf
,
3989 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3994 int pid
= ptid_get_pid (inferior_ptid
);
3999 return TARGET_XFER_E_IO
;
4002 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4005 return TARGET_XFER_E_IO
;
4007 return TARGET_XFER_EOF
;
4010 *xfered_len
= (ULONGEST
) l
;
4011 return TARGET_XFER_OK
;
4016 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4017 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4019 return TARGET_XFER_E_IO
;
4022 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4025 return TARGET_XFER_EOF
;
4029 ret
= write (fd
, writebuf
, (size_t) len
);
4031 ret
= read (fd
, readbuf
, (size_t) len
);
4036 return TARGET_XFER_E_IO
;
4038 return TARGET_XFER_EOF
;
4041 *xfered_len
= (ULONGEST
) ret
;
4042 return TARGET_XFER_OK
;
4047 /* Parse LINE as a signal set and add its set bits to SIGS. */
4050 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4052 int len
= strlen (line
) - 1;
4056 if (line
[len
] != '\n')
4057 error (_("Could not parse signal set: %s"), line
);
4065 if (*p
>= '0' && *p
<= '9')
4067 else if (*p
>= 'a' && *p
<= 'f')
4068 digit
= *p
- 'a' + 10;
4070 error (_("Could not parse signal set: %s"), line
);
4075 sigaddset (sigs
, signum
+ 1);
4077 sigaddset (sigs
, signum
+ 2);
4079 sigaddset (sigs
, signum
+ 3);
4081 sigaddset (sigs
, signum
+ 4);
4087 /* Find process PID's pending signals from /proc/pid/status and set
4091 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4092 sigset_t
*blocked
, sigset_t
*ignored
)
4095 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4096 struct cleanup
*cleanup
;
4098 sigemptyset (pending
);
4099 sigemptyset (blocked
);
4100 sigemptyset (ignored
);
4101 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4102 procfile
= gdb_fopen_cloexec (fname
, "r");
4103 if (procfile
== NULL
)
4104 error (_("Could not open %s"), fname
);
4105 cleanup
= make_cleanup_fclose (procfile
);
4107 while (fgets (buffer
, PATH_MAX
, procfile
) != NULL
)
4109 /* Normal queued signals are on the SigPnd line in the status
4110 file. However, 2.6 kernels also have a "shared" pending
4111 queue for delivering signals to a thread group, so check for
4114 Unfortunately some Red Hat kernels include the shared pending
4115 queue but not the ShdPnd status field. */
4117 if (strncmp (buffer
, "SigPnd:\t", 8) == 0)
4118 add_line_to_sigset (buffer
+ 8, pending
);
4119 else if (strncmp (buffer
, "ShdPnd:\t", 8) == 0)
4120 add_line_to_sigset (buffer
+ 8, pending
);
4121 else if (strncmp (buffer
, "SigBlk:\t", 8) == 0)
4122 add_line_to_sigset (buffer
+ 8, blocked
);
4123 else if (strncmp (buffer
, "SigIgn:\t", 8) == 0)
4124 add_line_to_sigset (buffer
+ 8, ignored
);
4127 do_cleanups (cleanup
);
4130 static enum target_xfer_status
4131 linux_nat_xfer_osdata (struct target_ops
*ops
, enum target_object object
,
4132 const char *annex
, gdb_byte
*readbuf
,
4133 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4134 ULONGEST
*xfered_len
)
4136 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4138 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4139 if (*xfered_len
== 0)
4140 return TARGET_XFER_EOF
;
4142 return TARGET_XFER_OK
;
4145 static enum target_xfer_status
4146 linux_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4147 const char *annex
, gdb_byte
*readbuf
,
4148 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4149 ULONGEST
*xfered_len
)
4151 enum target_xfer_status xfer
;
4153 if (object
== TARGET_OBJECT_AUXV
)
4154 return memory_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4155 offset
, len
, xfered_len
);
4157 if (object
== TARGET_OBJECT_OSDATA
)
4158 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4159 offset
, len
, xfered_len
);
4161 if (object
== TARGET_OBJECT_SPU
)
4162 return linux_proc_xfer_spu (ops
, object
, annex
, readbuf
, writebuf
,
4163 offset
, len
, xfered_len
);
4165 /* GDB calculates all the addresses in possibly larget width of the address.
4166 Address width needs to be masked before its final use - either by
4167 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4169 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4171 if (object
== TARGET_OBJECT_MEMORY
)
4173 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
4175 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
4176 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
4179 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4180 offset
, len
, xfered_len
);
4181 if (xfer
!= TARGET_XFER_EOF
)
4184 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4185 offset
, len
, xfered_len
);
4189 cleanup_target_stop (void *arg
)
4191 ptid_t
*ptid
= (ptid_t
*) arg
;
4193 gdb_assert (arg
!= NULL
);
4196 target_resume (*ptid
, 0, GDB_SIGNAL_0
);
4199 static VEC(static_tracepoint_marker_p
) *
4200 linux_child_static_tracepoint_markers_by_strid (struct target_ops
*self
,
4203 char s
[IPA_CMD_BUF_SIZE
];
4204 struct cleanup
*old_chain
;
4205 int pid
= ptid_get_pid (inferior_ptid
);
4206 VEC(static_tracepoint_marker_p
) *markers
= NULL
;
4207 struct static_tracepoint_marker
*marker
= NULL
;
4209 ptid_t ptid
= ptid_build (pid
, 0, 0);
4214 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4215 s
[sizeof ("qTfSTM")] = 0;
4217 agent_run_command (pid
, s
, strlen (s
) + 1);
4219 old_chain
= make_cleanup (free_current_marker
, &marker
);
4220 make_cleanup (cleanup_target_stop
, &ptid
);
4225 marker
= XCNEW (struct static_tracepoint_marker
);
4229 parse_static_tracepoint_marker_definition (p
, &p
, marker
);
4231 if (strid
== NULL
|| strcmp (strid
, marker
->str_id
) == 0)
4233 VEC_safe_push (static_tracepoint_marker_p
,
4239 release_static_tracepoint_marker (marker
);
4240 memset (marker
, 0, sizeof (*marker
));
4243 while (*p
++ == ','); /* comma-separated list */
4245 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4246 s
[sizeof ("qTsSTM")] = 0;
4247 agent_run_command (pid
, s
, strlen (s
) + 1);
4251 do_cleanups (old_chain
);
4256 /* Create a prototype generic GNU/Linux target. The client can override
4257 it with local methods. */
4260 linux_target_install_ops (struct target_ops
*t
)
4262 t
->to_insert_fork_catchpoint
= linux_child_insert_fork_catchpoint
;
4263 t
->to_remove_fork_catchpoint
= linux_child_remove_fork_catchpoint
;
4264 t
->to_insert_vfork_catchpoint
= linux_child_insert_vfork_catchpoint
;
4265 t
->to_remove_vfork_catchpoint
= linux_child_remove_vfork_catchpoint
;
4266 t
->to_insert_exec_catchpoint
= linux_child_insert_exec_catchpoint
;
4267 t
->to_remove_exec_catchpoint
= linux_child_remove_exec_catchpoint
;
4268 t
->to_set_syscall_catchpoint
= linux_child_set_syscall_catchpoint
;
4269 t
->to_pid_to_exec_file
= linux_child_pid_to_exec_file
;
4270 t
->to_post_startup_inferior
= linux_child_post_startup_inferior
;
4271 t
->to_post_attach
= linux_child_post_attach
;
4272 t
->to_follow_fork
= linux_child_follow_fork
;
4274 super_xfer_partial
= t
->to_xfer_partial
;
4275 t
->to_xfer_partial
= linux_xfer_partial
;
4277 t
->to_static_tracepoint_markers_by_strid
4278 = linux_child_static_tracepoint_markers_by_strid
;
4284 struct target_ops
*t
;
4286 t
= inf_ptrace_target ();
4287 linux_target_install_ops (t
);
4293 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4295 struct target_ops
*t
;
4297 t
= inf_ptrace_trad_target (register_u_offset
);
4298 linux_target_install_ops (t
);
4303 /* target_is_async_p implementation. */
4306 linux_nat_is_async_p (struct target_ops
*ops
)
4308 return linux_is_async_p ();
4311 /* target_can_async_p implementation. */
4314 linux_nat_can_async_p (struct target_ops
*ops
)
4316 /* NOTE: palves 2008-03-21: We're only async when the user requests
4317 it explicitly with the "set target-async" command.
4318 Someday, linux will always be async. */
4319 return target_async_permitted
;
4323 linux_nat_supports_non_stop (struct target_ops
*self
)
4328 /* True if we want to support multi-process. To be removed when GDB
4329 supports multi-exec. */
4331 int linux_multi_process
= 1;
4334 linux_nat_supports_multi_process (struct target_ops
*self
)
4336 return linux_multi_process
;
4340 linux_nat_supports_disable_randomization (struct target_ops
*self
)
4342 #ifdef HAVE_PERSONALITY
4349 static int async_terminal_is_ours
= 1;
4351 /* target_terminal_inferior implementation.
4353 This is a wrapper around child_terminal_inferior to add async support. */
4356 linux_nat_terminal_inferior (struct target_ops
*self
)
4358 /* Like target_terminal_inferior, use target_can_async_p, not
4359 target_is_async_p, since at this point the target is not async
4360 yet. If it can async, then we know it will become async prior to
4362 if (!target_can_async_p ())
4364 /* Async mode is disabled. */
4365 child_terminal_inferior (self
);
4369 child_terminal_inferior (self
);
4371 /* Calls to target_terminal_*() are meant to be idempotent. */
4372 if (!async_terminal_is_ours
)
4375 delete_file_handler (input_fd
);
4376 async_terminal_is_ours
= 0;
4380 /* target_terminal_ours implementation.
4382 This is a wrapper around child_terminal_ours to add async support (and
4383 implement the target_terminal_ours vs target_terminal_ours_for_output
4384 distinction). child_terminal_ours is currently no different than
4385 child_terminal_ours_for_output.
4386 We leave target_terminal_ours_for_output alone, leaving it to
4387 child_terminal_ours_for_output. */
4390 linux_nat_terminal_ours (struct target_ops
*self
)
4392 /* GDB should never give the terminal to the inferior if the
4393 inferior is running in the background (run&, continue&, etc.),
4394 but claiming it sure should. */
4395 child_terminal_ours (self
);
4397 if (async_terminal_is_ours
)
4400 clear_sigint_trap ();
4401 add_file_handler (input_fd
, stdin_event_handler
, 0);
4402 async_terminal_is_ours
= 1;
4405 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4407 static void *async_client_context
;
4409 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4410 so we notice when any child changes state, and notify the
4411 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4412 above to wait for the arrival of a SIGCHLD. */
4415 sigchld_handler (int signo
)
4417 int old_errno
= errno
;
4419 if (debug_linux_nat
)
4420 ui_file_write_async_safe (gdb_stdlog
,
4421 "sigchld\n", sizeof ("sigchld\n") - 1);
4423 if (signo
== SIGCHLD
4424 && linux_nat_event_pipe
[0] != -1)
4425 async_file_mark (); /* Let the event loop know that there are
4426 events to handle. */
4431 /* Callback registered with the target events file descriptor. */
4434 handle_target_event (int error
, gdb_client_data client_data
)
4436 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4439 /* Create/destroy the target events pipe. Returns previous state. */
4442 linux_async_pipe (int enable
)
4444 int previous
= linux_is_async_p ();
4446 if (previous
!= enable
)
4450 /* Block child signals while we create/destroy the pipe, as
4451 their handler writes to it. */
4452 block_child_signals (&prev_mask
);
4456 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4457 internal_error (__FILE__
, __LINE__
,
4458 "creating event pipe failed.");
4460 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4461 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4465 close (linux_nat_event_pipe
[0]);
4466 close (linux_nat_event_pipe
[1]);
4467 linux_nat_event_pipe
[0] = -1;
4468 linux_nat_event_pipe
[1] = -1;
4471 restore_child_signals_mask (&prev_mask
);
4477 /* target_async implementation. */
4480 linux_nat_async (struct target_ops
*ops
,
4481 void (*callback
) (enum inferior_event_type event_type
,
4485 if (callback
!= NULL
)
4487 async_client_callback
= callback
;
4488 async_client_context
= context
;
4489 if (!linux_async_pipe (1))
4491 add_file_handler (linux_nat_event_pipe
[0],
4492 handle_target_event
, NULL
);
4493 /* There may be pending events to handle. Tell the event loop
4500 async_client_callback
= callback
;
4501 async_client_context
= context
;
4502 delete_file_handler (linux_nat_event_pipe
[0]);
4503 linux_async_pipe (0);
4508 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4512 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4516 if (debug_linux_nat
)
4517 fprintf_unfiltered (gdb_stdlog
,
4518 "LNSL: running -> suspending %s\n",
4519 target_pid_to_str (lwp
->ptid
));
4522 if (lwp
->last_resume_kind
== resume_stop
)
4524 if (debug_linux_nat
)
4525 fprintf_unfiltered (gdb_stdlog
,
4526 "linux-nat: already stopping LWP %ld at "
4528 ptid_get_lwp (lwp
->ptid
));
4532 stop_callback (lwp
, NULL
);
4533 lwp
->last_resume_kind
= resume_stop
;
4537 /* Already known to be stopped; do nothing. */
4539 if (debug_linux_nat
)
4541 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4542 fprintf_unfiltered (gdb_stdlog
,
4543 "LNSL: already stopped/stop_requested %s\n",
4544 target_pid_to_str (lwp
->ptid
));
4546 fprintf_unfiltered (gdb_stdlog
,
4547 "LNSL: already stopped/no "
4548 "stop_requested yet %s\n",
4549 target_pid_to_str (lwp
->ptid
));
4556 linux_nat_stop (struct target_ops
*self
, ptid_t ptid
)
4559 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4561 linux_ops
->to_stop (linux_ops
, ptid
);
4565 linux_nat_close (struct target_ops
*self
)
4567 /* Unregister from the event loop. */
4568 if (linux_nat_is_async_p (self
))
4569 linux_nat_async (self
, NULL
, NULL
);
4571 if (linux_ops
->to_close
)
4572 linux_ops
->to_close (linux_ops
);
4577 /* When requests are passed down from the linux-nat layer to the
4578 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4579 used. The address space pointer is stored in the inferior object,
4580 but the common code that is passed such ptid can't tell whether
4581 lwpid is a "main" process id or not (it assumes so). We reverse
4582 look up the "main" process id from the lwp here. */
4584 static struct address_space
*
4585 linux_nat_thread_address_space (struct target_ops
*t
, ptid_t ptid
)
4587 struct lwp_info
*lwp
;
4588 struct inferior
*inf
;
4591 if (ptid_get_lwp (ptid
) == 0)
4593 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4595 lwp
= find_lwp_pid (ptid
);
4596 pid
= ptid_get_pid (lwp
->ptid
);
4600 /* A (pid,lwpid,0) ptid. */
4601 pid
= ptid_get_pid (ptid
);
4604 inf
= find_inferior_pid (pid
);
4605 gdb_assert (inf
!= NULL
);
4609 /* Return the cached value of the processor core for thread PTID. */
4612 linux_nat_core_of_thread (struct target_ops
*ops
, ptid_t ptid
)
4614 struct lwp_info
*info
= find_lwp_pid (ptid
);
4622 linux_nat_add_target (struct target_ops
*t
)
4624 /* Save the provided single-threaded target. We save this in a separate
4625 variable because another target we've inherited from (e.g. inf-ptrace)
4626 may have saved a pointer to T; we want to use it for the final
4627 process stratum target. */
4628 linux_ops_saved
= *t
;
4629 linux_ops
= &linux_ops_saved
;
4631 /* Override some methods for multithreading. */
4632 t
->to_create_inferior
= linux_nat_create_inferior
;
4633 t
->to_attach
= linux_nat_attach
;
4634 t
->to_detach
= linux_nat_detach
;
4635 t
->to_resume
= linux_nat_resume
;
4636 t
->to_wait
= linux_nat_wait
;
4637 t
->to_pass_signals
= linux_nat_pass_signals
;
4638 t
->to_xfer_partial
= linux_nat_xfer_partial
;
4639 t
->to_kill
= linux_nat_kill
;
4640 t
->to_mourn_inferior
= linux_nat_mourn_inferior
;
4641 t
->to_thread_alive
= linux_nat_thread_alive
;
4642 t
->to_pid_to_str
= linux_nat_pid_to_str
;
4643 t
->to_thread_name
= linux_nat_thread_name
;
4644 t
->to_has_thread_control
= tc_schedlock
;
4645 t
->to_thread_address_space
= linux_nat_thread_address_space
;
4646 t
->to_stopped_by_watchpoint
= linux_nat_stopped_by_watchpoint
;
4647 t
->to_stopped_data_address
= linux_nat_stopped_data_address
;
4649 t
->to_can_async_p
= linux_nat_can_async_p
;
4650 t
->to_is_async_p
= linux_nat_is_async_p
;
4651 t
->to_supports_non_stop
= linux_nat_supports_non_stop
;
4652 t
->to_async
= linux_nat_async
;
4653 t
->to_terminal_inferior
= linux_nat_terminal_inferior
;
4654 t
->to_terminal_ours
= linux_nat_terminal_ours
;
4656 super_close
= t
->to_close
;
4657 t
->to_close
= linux_nat_close
;
4659 /* Methods for non-stop support. */
4660 t
->to_stop
= linux_nat_stop
;
4662 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
4664 t
->to_supports_disable_randomization
4665 = linux_nat_supports_disable_randomization
;
4667 t
->to_core_of_thread
= linux_nat_core_of_thread
;
4669 /* We don't change the stratum; this target will sit at
4670 process_stratum and thread_db will set at thread_stratum. This
4671 is a little strange, since this is a multi-threaded-capable
4672 target, but we want to be on the stack below thread_db, and we
4673 also want to be used for single-threaded processes. */
4678 /* Register a method to call whenever a new thread is attached. */
4680 linux_nat_set_new_thread (struct target_ops
*t
,
4681 void (*new_thread
) (struct lwp_info
*))
4683 /* Save the pointer. We only support a single registered instance
4684 of the GNU/Linux native target, so we do not need to map this to
4686 linux_nat_new_thread
= new_thread
;
4689 /* See declaration in linux-nat.h. */
4692 linux_nat_set_new_fork (struct target_ops
*t
,
4693 linux_nat_new_fork_ftype
*new_fork
)
4695 /* Save the pointer. */
4696 linux_nat_new_fork
= new_fork
;
4699 /* See declaration in linux-nat.h. */
4702 linux_nat_set_forget_process (struct target_ops
*t
,
4703 linux_nat_forget_process_ftype
*fn
)
4705 /* Save the pointer. */
4706 linux_nat_forget_process_hook
= fn
;
4709 /* See declaration in linux-nat.h. */
4712 linux_nat_forget_process (pid_t pid
)
4714 if (linux_nat_forget_process_hook
!= NULL
)
4715 linux_nat_forget_process_hook (pid
);
4718 /* Register a method that converts a siginfo object between the layout
4719 that ptrace returns, and the layout in the architecture of the
4722 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4723 int (*siginfo_fixup
) (siginfo_t
*,
4727 /* Save the pointer. */
4728 linux_nat_siginfo_fixup
= siginfo_fixup
;
4731 /* Register a method to call prior to resuming a thread. */
4734 linux_nat_set_prepare_to_resume (struct target_ops
*t
,
4735 void (*prepare_to_resume
) (struct lwp_info
*))
4737 /* Save the pointer. */
4738 linux_nat_prepare_to_resume
= prepare_to_resume
;
4741 /* See linux-nat.h. */
4744 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4748 pid
= ptid_get_lwp (ptid
);
4750 pid
= ptid_get_pid (ptid
);
4753 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4756 memset (siginfo
, 0, sizeof (*siginfo
));
4762 /* Provide a prototype to silence -Wmissing-prototypes. */
4763 extern initialize_file_ftype _initialize_linux_nat
;
4766 _initialize_linux_nat (void)
4768 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4769 &debug_linux_nat
, _("\
4770 Set debugging of GNU/Linux lwp module."), _("\
4771 Show debugging of GNU/Linux lwp module."), _("\
4772 Enables printf debugging output."),
4774 show_debug_linux_nat
,
4775 &setdebuglist
, &showdebuglist
);
4777 /* Save this mask as the default. */
4778 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
4780 /* Install a SIGCHLD handler. */
4781 sigchld_action
.sa_handler
= sigchld_handler
;
4782 sigemptyset (&sigchld_action
.sa_mask
);
4783 sigchld_action
.sa_flags
= SA_RESTART
;
4785 /* Make it the default. */
4786 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4788 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4789 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4790 sigdelset (&suspend_mask
, SIGCHLD
);
4792 sigemptyset (&blocked_mask
);
4794 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
4795 support read-only process state. */
4796 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
4797 | PTRACE_O_TRACEVFORKDONE
4798 | PTRACE_O_TRACEVFORK
4799 | PTRACE_O_TRACEFORK
4800 | PTRACE_O_TRACEEXEC
);
4804 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4805 the GNU/Linux Threads library and therefore doesn't really belong
4808 /* Read variable NAME in the target and return its value if found.
4809 Otherwise return zero. It is assumed that the type of the variable
4813 get_signo (const char *name
)
4815 struct bound_minimal_symbol ms
;
4818 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
4819 if (ms
.minsym
== NULL
)
4822 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
4823 sizeof (signo
)) != 0)
4829 /* Return the set of signals used by the threads library in *SET. */
4832 lin_thread_get_thread_signals (sigset_t
*set
)
4834 struct sigaction action
;
4835 int restart
, cancel
;
4837 sigemptyset (&blocked_mask
);
4840 restart
= get_signo ("__pthread_sig_restart");
4841 cancel
= get_signo ("__pthread_sig_cancel");
4843 /* LinuxThreads normally uses the first two RT signals, but in some legacy
4844 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
4845 not provide any way for the debugger to query the signal numbers -
4846 fortunately they don't change! */
4849 restart
= __SIGRTMIN
;
4852 cancel
= __SIGRTMIN
+ 1;
4854 sigaddset (set
, restart
);
4855 sigaddset (set
, cancel
);
4857 /* The GNU/Linux Threads library makes terminating threads send a
4858 special "cancel" signal instead of SIGCHLD. Make sure we catch
4859 those (to prevent them from terminating GDB itself, which is
4860 likely to be their default action) and treat them the same way as
4863 action
.sa_handler
= sigchld_handler
;
4864 sigemptyset (&action
.sa_mask
);
4865 action
.sa_flags
= SA_RESTART
;
4866 sigaction (cancel
, &action
, NULL
);
4868 /* We block the "cancel" signal throughout this code ... */
4869 sigaddset (&blocked_mask
, cancel
);
4870 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
4872 /* ... except during a sigsuspend. */
4873 sigdelset (&suspend_mask
, cancel
);