1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2015 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
27 #ifdef HAVE_TKILL_SYSCALL
29 #include <sys/syscall.h>
31 #include <sys/ptrace.h>
32 #include "linux-nat.h"
33 #include "nat/linux-ptrace.h"
34 #include "nat/linux-procfs.h"
35 #include "nat/linux-personality.h"
36 #include "linux-fork.h"
37 #include "gdbthread.h"
41 #include "inf-child.h"
42 #include "inf-ptrace.h"
44 #include <sys/procfs.h> /* for elf_gregset etc. */
45 #include "elf-bfd.h" /* for elfcore_write_* */
46 #include "gregset.h" /* for gregset */
47 #include "gdbcore.h" /* for get_exec_file */
48 #include <ctype.h> /* for isdigit */
49 #include <sys/stat.h> /* for struct stat */
50 #include <fcntl.h> /* for O_RDONLY */
52 #include "event-loop.h"
53 #include "event-top.h"
55 #include <sys/types.h>
57 #include "xml-support.h"
60 #include "nat/linux-osdata.h"
61 #include "linux-tdep.h"
64 #include "tracepoint.h"
66 #include "target-descriptions.h"
67 #include "filestuff.h"
71 #define SPUFS_MAGIC 0x23c9b64e
74 /* This comment documents high-level logic of this file.
76 Waiting for events in sync mode
77 ===============================
79 When waiting for an event in a specific thread, we just use waitpid, passing
80 the specific pid, and not passing WNOHANG.
82 When waiting for an event in all threads, waitpid is not quite good. Prior to
83 version 2.4, Linux can either wait for event in main thread, or in secondary
84 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
85 miss an event. The solution is to use non-blocking waitpid, together with
86 sigsuspend. First, we use non-blocking waitpid to get an event in the main
87 process, if any. Second, we use non-blocking waitpid with the __WCLONED
88 flag to check for events in cloned processes. If nothing is found, we use
89 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
90 happened to a child process -- and SIGCHLD will be delivered both for events
91 in main debugged process and in cloned processes. As soon as we know there's
92 an event, we get back to calling nonblocking waitpid with and without
95 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
96 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
97 blocked, the signal becomes pending and sigsuspend immediately
98 notices it and returns.
100 Waiting for events in async mode
101 ================================
103 In async mode, GDB should always be ready to handle both user input
104 and target events, so neither blocking waitpid nor sigsuspend are
105 viable options. Instead, we should asynchronously notify the GDB main
106 event loop whenever there's an unprocessed event from the target. We
107 detect asynchronous target events by handling SIGCHLD signals. To
108 notify the event loop about target events, the self-pipe trick is used
109 --- a pipe is registered as waitable event source in the event loop,
110 the event loop select/poll's on the read end of this pipe (as well on
111 other event sources, e.g., stdin), and the SIGCHLD handler writes a
112 byte to this pipe. This is more portable than relying on
113 pselect/ppoll, since on kernels that lack those syscalls, libc
114 emulates them with select/poll+sigprocmask, and that is racy
115 (a.k.a. plain broken).
117 Obviously, if we fail to notify the event loop if there's a target
118 event, it's bad. OTOH, if we notify the event loop when there's no
119 event from the target, linux_nat_wait will detect that there's no real
120 event to report, and return event of type TARGET_WAITKIND_IGNORE.
121 This is mostly harmless, but it will waste time and is better avoided.
123 The main design point is that every time GDB is outside linux-nat.c,
124 we have a SIGCHLD handler installed that is called when something
125 happens to the target and notifies the GDB event loop. Whenever GDB
126 core decides to handle the event, and calls into linux-nat.c, we
127 process things as in sync mode, except that the we never block in
130 While processing an event, we may end up momentarily blocked in
131 waitpid calls. Those waitpid calls, while blocking, are guarantied to
132 return quickly. E.g., in all-stop mode, before reporting to the core
133 that an LWP hit a breakpoint, all LWPs are stopped by sending them
134 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
135 Note that this is different from blocking indefinitely waiting for the
136 next event --- here, we're already handling an event.
141 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
142 signal is not entirely significant; we just need for a signal to be delivered,
143 so that we can intercept it. SIGSTOP's advantage is that it can not be
144 blocked. A disadvantage is that it is not a real-time signal, so it can only
145 be queued once; we do not keep track of other sources of SIGSTOP.
147 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
148 use them, because they have special behavior when the signal is generated -
149 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
150 kills the entire thread group.
152 A delivered SIGSTOP would stop the entire thread group, not just the thread we
153 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
154 cancel it (by PTRACE_CONT without passing SIGSTOP).
156 We could use a real-time signal instead. This would solve those problems; we
157 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
158 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
159 generates it, and there are races with trying to find a signal that is not
163 #define O_LARGEFILE 0
166 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
167 the use of the multi-threaded target. */
168 static struct target_ops *linux_ops;
169 static struct target_ops linux_ops_saved;
171 /* The method to call, if any, when a new thread is attached. */
172 static void (*linux_nat_new_thread) (struct lwp_info *);
174 /* The method to call, if any, when a new fork is attached. */
175 static linux_nat_new_fork_ftype *linux_nat_new_fork;
177 /* The method to call, if any, when a process is no longer
179 static linux_nat_forget_process_ftype *linux_nat_forget_process_hook;
181 /* Hook to call prior to resuming a thread. */
182 static void (*linux_nat_prepare_to_resume) (struct lwp_info *);
184 /* The method to call, if any, when the siginfo object needs to be
185 converted between the layout returned by ptrace, and the layout in
186 the architecture of the inferior. */
187 static int (*linux_nat_siginfo_fixup) (siginfo_t *,
191 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
192 Called by our to_xfer_partial. */
193 static target_xfer_partial_ftype *super_xfer_partial;
195 /* The saved to_close method, inherited from inf-ptrace.c.
196 Called by our to_close. */
197 static void (*super_close) (struct target_ops *);
199 static unsigned int debug_linux_nat;
201 show_debug_linux_nat (struct ui_file *file, int from_tty,
202 struct cmd_list_element *c, const char *value)
204 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
208 struct simple_pid_list
212 struct simple_pid_list *next;
214 struct simple_pid_list *stopped_pids;
216 /* Async mode support. */
218 /* The read/write ends of the pipe registered as waitable file in the
220 static int linux_nat_event_pipe[2] = { -1, -1 };
222 /* True if we're currently in async mode. */
223 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
225 /* Flush the event pipe. */
228 async_file_flush (void)
235 ret = read (linux_nat_event_pipe[0], &buf, 1);
237 while (ret >= 0 || (ret == -1 && errno == EINTR));
240 /* Put something (anything, doesn't matter what, or how much) in event
241 pipe, so that the select/poll in the event-loop realizes we have
242 something to process. */
245 async_file_mark (void)
249 /* It doesn't really matter what the pipe contains, as long we end
250 up with something in it. Might as well flush the previous
256 ret = write (linux_nat_event_pipe[1], "+", 1);
258 while (ret == -1 && errno == EINTR);
260 /* Ignore EAGAIN. If the pipe is full, the event loop will already
261 be awakened anyway. */
264 static int kill_lwp (int lwpid, int signo);
266 static int stop_callback (struct lwp_info *lp, void *data);
267 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
269 static void block_child_signals (sigset_t *prev_mask);
270 static void restore_child_signals_mask (sigset_t *prev_mask);
273 static struct lwp_info *add_lwp (ptid_t ptid);
274 static void purge_lwp_list (int pid);
275 static void delete_lwp (ptid_t ptid);
276 static struct lwp_info *find_lwp_pid (ptid_t ptid);
278 static int lwp_status_pending_p (struct lwp_info *lp);
280 static int check_stopped_by_breakpoint (struct lwp_info *lp);
281 static int sigtrap_is_event (int status);
282 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
287 /* See nat/linux-nat.h. */
290 ptid_of_lwp (struct lwp_info *lwp)
295 /* See nat/linux-nat.h. */
298 lwp_set_arch_private_info (struct lwp_info *lwp,
299 struct arch_lwp_info *info)
301 lwp->arch_private = info;
304 /* See nat/linux-nat.h. */
306 struct arch_lwp_info *
307 lwp_arch_private_info (struct lwp_info *lwp)
309 return lwp->arch_private;
312 /* See nat/linux-nat.h. */
315 lwp_is_stopped (struct lwp_info *lwp)
320 /* See nat/linux-nat.h. */
322 enum target_stop_reason
323 lwp_stop_reason (struct lwp_info *lwp)
325 return lwp->stop_reason;
329 /* Trivial list manipulation functions to keep track of a list of
330 new stopped processes. */
332 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
334 struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
337 new_pid->status = status;
338 new_pid->next = *listp;
343 in_pid_list_p (struct simple_pid_list *list, int pid)
345 struct simple_pid_list *p;
347 for (p = list; p != NULL; p = p->next)
354 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
356 struct simple_pid_list **p;
358 for (p = listp; *p != NULL; p = &(*p)->next)
359 if ((*p)->pid == pid)
361 struct simple_pid_list *next = (*p)->next;
363 *statusp = (*p)->status;
371 /* Initialize ptrace warnings and check for supported ptrace
374 ATTACHED should be nonzero iff we attached to the inferior. */
377 linux_init_ptrace (pid_t pid, int attached)
379 linux_enable_event_reporting (pid, attached);
380 linux_ptrace_init_warnings ();
384 linux_child_post_attach (struct target_ops *self, int pid)
386 linux_init_ptrace (pid, 1);
390 linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
392 linux_init_ptrace (ptid_get_pid (ptid), 0);
395 /* Return the number of known LWPs in the tgid given by PID. */
403 for (lp = lwp_list; lp; lp = lp->next)
404 if (ptid_get_pid (lp->ptid) == pid)
410 /* Call delete_lwp with prototype compatible for make_cleanup. */
413 delete_lwp_cleanup (void *lp_voidp)
415 struct lwp_info *lp = lp_voidp;
417 delete_lwp (lp->ptid);
420 /* Target hook for follow_fork. On entry inferior_ptid must be the
421 ptid of the followed inferior. At return, inferior_ptid will be
425 linux_child_follow_fork (struct target_ops *ops, int follow_child,
430 struct lwp_info *child_lp = NULL;
431 int status = W_STOPCODE (0);
432 struct cleanup *old_chain;
434 ptid_t parent_ptid, child_ptid;
435 int parent_pid, child_pid;
437 has_vforked = (inferior_thread ()->pending_follow.kind
438 == TARGET_WAITKIND_VFORKED);
439 parent_ptid = inferior_ptid;
440 child_ptid = inferior_thread ()->pending_follow.value.related_pid;
441 parent_pid = ptid_get_lwp (parent_ptid);
442 child_pid = ptid_get_lwp (child_ptid);
444 /* We're already attached to the parent, by default. */
445 old_chain = save_inferior_ptid ();
446 inferior_ptid = child_ptid;
447 child_lp = add_lwp (inferior_ptid);
448 child_lp->stopped = 1;
449 child_lp->last_resume_kind = resume_stop;
451 /* Detach new forked process? */
454 make_cleanup (delete_lwp_cleanup, child_lp);
456 if (linux_nat_prepare_to_resume != NULL)
457 linux_nat_prepare_to_resume (child_lp);
459 /* When debugging an inferior in an architecture that supports
460 hardware single stepping on a kernel without commit
461 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
462 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
463 set if the parent process had them set.
464 To work around this, single step the child process
465 once before detaching to clear the flags. */
467 if (!gdbarch_software_single_step_p (target_thread_architecture
470 linux_disable_event_reporting (child_pid);
471 if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
472 perror_with_name (_("Couldn't do single step"));
473 if (my_waitpid (child_pid, &status, 0) < 0)
474 perror_with_name (_("Couldn't wait vfork process"));
477 if (WIFSTOPPED (status))
481 signo = WSTOPSIG (status);
483 && !signal_pass_state (gdb_signal_from_host (signo)))
485 ptrace (PTRACE_DETACH, child_pid, 0, signo);
488 /* Resets value of inferior_ptid to parent ptid. */
489 do_cleanups (old_chain);
493 /* Let the thread_db layer learn about this new process. */
494 check_for_thread_db ();
497 do_cleanups (old_chain);
501 struct lwp_info *parent_lp;
503 parent_lp = find_lwp_pid (parent_ptid);
504 gdb_assert (linux_supports_tracefork () >= 0);
506 if (linux_supports_tracevforkdone ())
509 fprintf_unfiltered (gdb_stdlog,
510 "LCFF: waiting for VFORK_DONE on %d\n",
512 parent_lp->stopped = 1;
514 /* We'll handle the VFORK_DONE event like any other
515 event, in target_wait. */
519 /* We can't insert breakpoints until the child has
520 finished with the shared memory region. We need to
521 wait until that happens. Ideal would be to just
523 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
524 - waitpid (parent_pid, &status, __WALL);
525 However, most architectures can't handle a syscall
526 being traced on the way out if it wasn't traced on
529 We might also think to loop, continuing the child
530 until it exits or gets a SIGTRAP. One problem is
531 that the child might call ptrace with PTRACE_TRACEME.
533 There's no simple and reliable way to figure out when
534 the vforked child will be done with its copy of the
535 shared memory. We could step it out of the syscall,
536 two instructions, let it go, and then single-step the
537 parent once. When we have hardware single-step, this
538 would work; with software single-step it could still
539 be made to work but we'd have to be able to insert
540 single-step breakpoints in the child, and we'd have
541 to insert -just- the single-step breakpoint in the
542 parent. Very awkward.
544 In the end, the best we can do is to make sure it
545 runs for a little while. Hopefully it will be out of
546 range of any breakpoints we reinsert. Usually this
547 is only the single-step breakpoint at vfork's return
551 fprintf_unfiltered (gdb_stdlog,
552 "LCFF: no VFORK_DONE "
553 "support, sleeping a bit\n");
557 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
558 and leave it pending. The next linux_nat_resume call
559 will notice a pending event, and bypasses actually
560 resuming the inferior. */
561 parent_lp->status = 0;
562 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
563 parent_lp->stopped = 1;
565 /* If we're in async mode, need to tell the event loop
566 there's something here to process. */
567 if (target_is_async_p ())
574 struct lwp_info *child_lp;
576 child_lp = add_lwp (inferior_ptid);
577 child_lp->stopped = 1;
578 child_lp->last_resume_kind = resume_stop;
580 /* Let the thread_db layer learn about this new process. */
581 check_for_thread_db ();
589 linux_child_insert_fork_catchpoint (struct target_ops *self, int pid)
591 return !linux_supports_tracefork ();
595 linux_child_remove_fork_catchpoint (struct target_ops *self, int pid)
601 linux_child_insert_vfork_catchpoint (struct target_ops *self, int pid)
603 return !linux_supports_tracefork ();
607 linux_child_remove_vfork_catchpoint (struct target_ops *self, int pid)
613 linux_child_insert_exec_catchpoint (struct target_ops *self, int pid)
615 return !linux_supports_tracefork ();
619 linux_child_remove_exec_catchpoint (struct target_ops *self, int pid)
625 linux_child_set_syscall_catchpoint (struct target_ops *self,
626 int pid, int needed, int any_count,
627 int table_size, int *table)
629 if (!linux_supports_tracesysgood ())
632 /* On GNU/Linux, we ignore the arguments. It means that we only
633 enable the syscall catchpoints, but do not disable them.
635 Also, we do not use the `table' information because we do not
636 filter system calls here. We let GDB do the logic for us. */
640 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
641 are processes sharing the same VM space. A multi-threaded process
642 is basically a group of such processes. However, such a grouping
643 is almost entirely a user-space issue; the kernel doesn't enforce
644 such a grouping at all (this might change in the future). In
645 general, we'll rely on the threads library (i.e. the GNU/Linux
646 Threads library) to provide such a grouping.
648 It is perfectly well possible to write a multi-threaded application
649 without the assistance of a threads library, by using the clone
650 system call directly. This module should be able to give some
651 rudimentary support for debugging such applications if developers
652 specify the CLONE_PTRACE flag in the clone system call, and are
653 using the Linux kernel 2.4 or above.
655 Note that there are some peculiarities in GNU/Linux that affect
658 - In general one should specify the __WCLONE flag to waitpid in
659 order to make it report events for any of the cloned processes
660 (and leave it out for the initial process). However, if a cloned
661 process has exited the exit status is only reported if the
662 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
663 we cannot use it since GDB must work on older systems too.
665 - When a traced, cloned process exits and is waited for by the
666 debugger, the kernel reassigns it to the original parent and
667 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
668 library doesn't notice this, which leads to the "zombie problem":
669 When debugged a multi-threaded process that spawns a lot of
670 threads will run out of processes, even if the threads exit,
671 because the "zombies" stay around. */
673 /* List of known LWPs. */
674 struct lwp_info *lwp_list;
677 /* Original signal mask. */
678 static sigset_t normal_mask;
680 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
681 _initialize_linux_nat. */
682 static sigset_t suspend_mask;
684 /* Signals to block to make that sigsuspend work. */
685 static sigset_t blocked_mask;
687 /* SIGCHLD action. */
688 struct sigaction sigchld_action;
690 /* Block child signals (SIGCHLD and linux threads signals), and store
691 the previous mask in PREV_MASK. */
694 block_child_signals (sigset_t *prev_mask)
696 /* Make sure SIGCHLD is blocked. */
697 if (!sigismember (&blocked_mask, SIGCHLD))
698 sigaddset (&blocked_mask, SIGCHLD);
700 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
703 /* Restore child signals mask, previously returned by
704 block_child_signals. */
707 restore_child_signals_mask (sigset_t *prev_mask)
709 sigprocmask (SIG_SETMASK, prev_mask, NULL);
712 /* Mask of signals to pass directly to the inferior. */
713 static sigset_t pass_mask;
715 /* Update signals to pass to the inferior. */
717 linux_nat_pass_signals (struct target_ops *self,
718 int numsigs, unsigned char *pass_signals)
722 sigemptyset (&pass_mask);
724 for (signo = 1; signo < NSIG; signo++)
726 int target_signo = gdb_signal_from_host (signo);
727 if (target_signo < numsigs && pass_signals[target_signo])
728 sigaddset (&pass_mask, signo);
734 /* Prototypes for local functions. */
735 static int stop_wait_callback (struct lwp_info *lp, void *data);
736 static int linux_thread_alive (ptid_t ptid);
737 static char *linux_child_pid_to_exec_file (struct target_ops *self, int pid);
738 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
742 /* Destroy and free LP. */
745 lwp_free (struct lwp_info *lp)
747 xfree (lp->arch_private);
751 /* Remove all LWPs belong to PID from the lwp list. */
754 purge_lwp_list (int pid)
756 struct lwp_info *lp, *lpprev, *lpnext;
760 for (lp = lwp_list; lp; lp = lpnext)
764 if (ptid_get_pid (lp->ptid) == pid)
769 lpprev->next = lp->next;
778 /* Add the LWP specified by PTID to the list. PTID is the first LWP
779 in the process. Return a pointer to the structure describing the
782 This differs from add_lwp in that we don't let the arch specific
783 bits know about this new thread. Current clients of this callback
784 take the opportunity to install watchpoints in the new thread, and
785 we shouldn't do that for the first thread. If we're spawning a
786 child ("run"), the thread executes the shell wrapper first, and we
787 shouldn't touch it until it execs the program we want to debug.
788 For "attach", it'd be okay to call the callback, but it's not
789 necessary, because watchpoints can't yet have been inserted into
792 static struct lwp_info *
793 add_initial_lwp (ptid_t ptid)
797 gdb_assert (ptid_lwp_p (ptid));
799 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
801 memset (lp, 0, sizeof (struct lwp_info));
803 lp->last_resume_kind = resume_continue;
804 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
815 /* Add the LWP specified by PID to the list. Return a pointer to the
816 structure describing the new LWP. The LWP should already be
819 static struct lwp_info *
820 add_lwp (ptid_t ptid)
824 lp = add_initial_lwp (ptid);
826 /* Let the arch specific bits know about this new thread. Current
827 clients of this callback take the opportunity to install
828 watchpoints in the new thread. We don't do this for the first
829 thread though. See add_initial_lwp. */
830 if (linux_nat_new_thread != NULL)
831 linux_nat_new_thread (lp);
836 /* Remove the LWP specified by PID from the list. */
839 delete_lwp (ptid_t ptid)
841 struct lwp_info *lp, *lpprev;
845 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
846 if (ptid_equal (lp->ptid, ptid))
853 lpprev->next = lp->next;
860 /* Return a pointer to the structure describing the LWP corresponding
861 to PID. If no corresponding LWP could be found, return NULL. */
863 static struct lwp_info *
864 find_lwp_pid (ptid_t ptid)
869 if (ptid_lwp_p (ptid))
870 lwp = ptid_get_lwp (ptid);
872 lwp = ptid_get_pid (ptid);
874 for (lp = lwp_list; lp; lp = lp->next)
875 if (lwp == ptid_get_lwp (lp->ptid))
881 /* See nat/linux-nat.h. */
884 iterate_over_lwps (ptid_t filter,
885 iterate_over_lwps_ftype callback,
888 struct lwp_info *lp, *lpnext;
890 for (lp = lwp_list; lp; lp = lpnext)
894 if (ptid_match (lp->ptid, filter))
896 if ((*callback) (lp, data) != 0)
904 /* Update our internal state when changing from one checkpoint to
905 another indicated by NEW_PTID. We can only switch single-threaded
906 applications, so we only create one new LWP, and the previous list
910 linux_nat_switch_fork (ptid_t new_ptid)
914 purge_lwp_list (ptid_get_pid (inferior_ptid));
916 lp = add_lwp (new_ptid);
919 /* This changes the thread's ptid while preserving the gdb thread
920 num. Also changes the inferior pid, while preserving the
922 thread_change_ptid (inferior_ptid, new_ptid);
924 /* We've just told GDB core that the thread changed target id, but,
925 in fact, it really is a different thread, with different register
927 registers_changed ();
930 /* Handle the exit of a single thread LP. */
933 exit_lwp (struct lwp_info *lp)
935 struct thread_info *th = find_thread_ptid (lp->ptid);
939 if (print_thread_events)
940 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
942 delete_thread (lp->ptid);
945 delete_lwp (lp->ptid);
948 /* Wait for the LWP specified by LP, which we have just attached to.
949 Returns a wait status for that LWP, to cache. */
952 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
955 pid_t new_pid, pid = ptid_get_lwp (ptid);
958 if (linux_proc_pid_is_stopped (pid))
961 fprintf_unfiltered (gdb_stdlog,
962 "LNPAW: Attaching to a stopped process\n");
964 /* The process is definitely stopped. It is in a job control
965 stop, unless the kernel predates the TASK_STOPPED /
966 TASK_TRACED distinction, in which case it might be in a
967 ptrace stop. Make sure it is in a ptrace stop; from there we
968 can kill it, signal it, et cetera.
970 First make sure there is a pending SIGSTOP. Since we are
971 already attached, the process can not transition from stopped
972 to running without a PTRACE_CONT; so we know this signal will
973 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
974 probably already in the queue (unless this kernel is old
975 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
976 is not an RT signal, it can only be queued once. */
977 kill_lwp (pid, SIGSTOP);
979 /* Finally, resume the stopped process. This will deliver the SIGSTOP
980 (or a higher priority signal, just like normal PTRACE_ATTACH). */
981 ptrace (PTRACE_CONT, pid, 0, 0);
984 /* Make sure the initial process is stopped. The user-level threads
985 layer might want to poke around in the inferior, and that won't
986 work if things haven't stabilized yet. */
987 new_pid = my_waitpid (pid, &status, 0);
988 if (new_pid == -1 && errno == ECHILD)
991 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
993 /* Try again with __WCLONE to check cloned processes. */
994 new_pid = my_waitpid (pid, &status, __WCLONE);
998 gdb_assert (pid == new_pid);
1000 if (!WIFSTOPPED (status))
1002 /* The pid we tried to attach has apparently just exited. */
1003 if (debug_linux_nat)
1004 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1005 pid, status_to_str (status));
1009 if (WSTOPSIG (status) != SIGSTOP)
1012 if (debug_linux_nat)
1013 fprintf_unfiltered (gdb_stdlog,
1014 "LNPAW: Received %s after attaching\n",
1015 status_to_str (status));
1021 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1022 the new LWP could not be attached, or 1 if we're already auto
1023 attached to this thread, but haven't processed the
1024 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1025 its existance, without considering it an error. */
1028 lin_lwp_attach_lwp (ptid_t ptid)
1030 struct lwp_info *lp;
1033 gdb_assert (ptid_lwp_p (ptid));
1035 lp = find_lwp_pid (ptid);
1036 lwpid = ptid_get_lwp (ptid);
1038 /* We assume that we're already attached to any LWP that is already
1039 in our list of LWPs. If we're not seeing exit events from threads
1040 and we've had PID wraparound since we last tried to stop all threads,
1041 this assumption might be wrong; fortunately, this is very unlikely
1045 int status, cloned = 0, signalled = 0;
1047 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1049 if (linux_supports_tracefork ())
1051 /* If we haven't stopped all threads when we get here,
1052 we may have seen a thread listed in thread_db's list,
1053 but not processed the PTRACE_EVENT_CLONE yet. If
1054 that's the case, ignore this new thread, and let
1055 normal event handling discover it later. */
1056 if (in_pid_list_p (stopped_pids, lwpid))
1058 /* We've already seen this thread stop, but we
1059 haven't seen the PTRACE_EVENT_CLONE extended
1061 if (debug_linux_nat)
1062 fprintf_unfiltered (gdb_stdlog,
1063 "LLAL: attach failed, but already seen "
1064 "this thread %s stop\n",
1065 target_pid_to_str (ptid));
1073 if (debug_linux_nat)
1074 fprintf_unfiltered (gdb_stdlog,
1075 "LLAL: attach failed, and haven't seen "
1076 "this thread %s stop yet\n",
1077 target_pid_to_str (ptid));
1079 /* We may or may not be attached to the LWP already.
1080 Try waitpid on it. If that errors, we're not
1081 attached to the LWP yet. Otherwise, we're
1082 already attached. */
1083 gdb_assert (lwpid > 0);
1084 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1085 if (new_pid == -1 && errno == ECHILD)
1086 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1091 /* The child hasn't stopped for its initial
1092 SIGSTOP stop yet. */
1093 if (debug_linux_nat)
1094 fprintf_unfiltered (gdb_stdlog,
1095 "LLAL: child hasn't "
1098 else if (WIFSTOPPED (status))
1100 if (debug_linux_nat)
1101 fprintf_unfiltered (gdb_stdlog,
1102 "LLAL: adding to stopped_pids\n");
1103 add_to_pid_list (&stopped_pids, lwpid, status);
1110 /* If we fail to attach to the thread, issue a warning,
1111 but continue. One way this can happen is if thread
1112 creation is interrupted; as of Linux kernel 2.6.19, a
1113 bug may place threads in the thread list and then fail
1115 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1116 safe_strerror (errno));
1120 if (debug_linux_nat)
1121 fprintf_unfiltered (gdb_stdlog,
1122 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1123 target_pid_to_str (ptid));
1125 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1126 if (!WIFSTOPPED (status))
1129 lp = add_lwp (ptid);
1131 lp->last_resume_kind = resume_stop;
1132 lp->cloned = cloned;
1133 lp->signalled = signalled;
1134 if (WSTOPSIG (status) != SIGSTOP)
1137 lp->status = status;
1140 target_post_attach (ptid_get_lwp (lp->ptid));
1142 if (debug_linux_nat)
1144 fprintf_unfiltered (gdb_stdlog,
1145 "LLAL: waitpid %s received %s\n",
1146 target_pid_to_str (ptid),
1147 status_to_str (status));
1155 linux_nat_create_inferior (struct target_ops *ops,
1156 char *exec_file, char *allargs, char **env,
1159 struct cleanup *restore_personality
1160 = maybe_disable_address_space_randomization (disable_randomization);
1162 /* The fork_child mechanism is synchronous and calls target_wait, so
1163 we have to mask the async mode. */
1165 /* Make sure we report all signals during startup. */
1166 linux_nat_pass_signals (ops, 0, NULL);
1168 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1170 do_cleanups (restore_personality);
1173 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1174 already attached. Returns true if a new LWP is found, false
1178 attach_proc_task_lwp_callback (ptid_t ptid)
1180 struct lwp_info *lp;
1182 /* Ignore LWPs we're already attached to. */
1183 lp = find_lwp_pid (ptid);
1186 int lwpid = ptid_get_lwp (ptid);
1188 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1192 /* Be quiet if we simply raced with the thread exiting.
1193 EPERM is returned if the thread's task still exists, and
1194 is marked as exited or zombie, as well as other
1195 conditions, so in that case, confirm the status in
1196 /proc/PID/status. */
1198 || (err == EPERM && linux_proc_pid_is_gone (lwpid)))
1200 if (debug_linux_nat)
1202 fprintf_unfiltered (gdb_stdlog,
1203 "Cannot attach to lwp %d: "
1204 "thread is gone (%d: %s)\n",
1205 lwpid, err, safe_strerror (err));
1210 warning (_("Cannot attach to lwp %d: %s"),
1212 linux_ptrace_attach_fail_reason_string (ptid,
1218 if (debug_linux_nat)
1219 fprintf_unfiltered (gdb_stdlog,
1220 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1221 target_pid_to_str (ptid));
1223 lp = add_lwp (ptid);
1226 /* The next time we wait for this LWP we'll see a SIGSTOP as
1227 PTRACE_ATTACH brings it to a halt. */
1230 /* We need to wait for a stop before being able to make the
1231 next ptrace call on this LWP. */
1232 lp->must_set_ptrace_flags = 1;
1241 linux_nat_attach (struct target_ops *ops, const char *args, int from_tty)
1243 struct lwp_info *lp;
1247 /* Make sure we report all signals during attach. */
1248 linux_nat_pass_signals (ops, 0, NULL);
1252 linux_ops->to_attach (ops, args, from_tty);
1254 CATCH (ex, RETURN_MASK_ERROR)
1256 pid_t pid = parse_pid_to_attach (args);
1257 struct buffer buffer;
1258 char *message, *buffer_s;
1260 message = xstrdup (ex.message);
1261 make_cleanup (xfree, message);
1263 buffer_init (&buffer);
1264 linux_ptrace_attach_fail_reason (pid, &buffer);
1266 buffer_grow_str0 (&buffer, "");
1267 buffer_s = buffer_finish (&buffer);
1268 make_cleanup (xfree, buffer_s);
1270 if (*buffer_s != '\0')
1271 throw_error (ex.error, "warning: %s\n%s", buffer_s, message);
1273 throw_error (ex.error, "%s", message);
1277 /* The ptrace base target adds the main thread with (pid,0,0)
1278 format. Decorate it with lwp info. */
1279 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1280 ptid_get_pid (inferior_ptid),
1282 thread_change_ptid (inferior_ptid, ptid);
1284 /* Add the initial process as the first LWP to the list. */
1285 lp = add_initial_lwp (ptid);
1287 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1289 if (!WIFSTOPPED (status))
1291 if (WIFEXITED (status))
1293 int exit_code = WEXITSTATUS (status);
1295 target_terminal_ours ();
1296 target_mourn_inferior ();
1298 error (_("Unable to attach: program exited normally."));
1300 error (_("Unable to attach: program exited with code %d."),
1303 else if (WIFSIGNALED (status))
1305 enum gdb_signal signo;
1307 target_terminal_ours ();
1308 target_mourn_inferior ();
1310 signo = gdb_signal_from_host (WTERMSIG (status));
1311 error (_("Unable to attach: program terminated with signal "
1313 gdb_signal_to_name (signo),
1314 gdb_signal_to_string (signo));
1317 internal_error (__FILE__, __LINE__,
1318 _("unexpected status %d for PID %ld"),
1319 status, (long) ptid_get_lwp (ptid));
1324 /* Save the wait status to report later. */
1326 if (debug_linux_nat)
1327 fprintf_unfiltered (gdb_stdlog,
1328 "LNA: waitpid %ld, saving status %s\n",
1329 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1331 lp->status = status;
1333 /* We must attach to every LWP. If /proc is mounted, use that to
1334 find them now. The inferior may be using raw clone instead of
1335 using pthreads. But even if it is using pthreads, thread_db
1336 walks structures in the inferior's address space to find the list
1337 of threads/LWPs, and those structures may well be corrupted.
1338 Note that once thread_db is loaded, we'll still use it to list
1339 threads and associate pthread info with each LWP. */
1340 linux_proc_attach_tgid_threads (ptid_get_pid (lp->ptid),
1341 attach_proc_task_lwp_callback);
1343 if (target_can_async_p ())
1347 /* Get pending status of LP. */
1349 get_pending_status (struct lwp_info *lp, int *status)
1351 enum gdb_signal signo = GDB_SIGNAL_0;
1353 /* If we paused threads momentarily, we may have stored pending
1354 events in lp->status or lp->waitstatus (see stop_wait_callback),
1355 and GDB core hasn't seen any signal for those threads.
1356 Otherwise, the last signal reported to the core is found in the
1357 thread object's stop_signal.
1359 There's a corner case that isn't handled here at present. Only
1360 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1361 stop_signal make sense as a real signal to pass to the inferior.
1362 Some catchpoint related events, like
1363 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1364 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1365 those traps are debug API (ptrace in our case) related and
1366 induced; the inferior wouldn't see them if it wasn't being
1367 traced. Hence, we should never pass them to the inferior, even
1368 when set to pass state. Since this corner case isn't handled by
1369 infrun.c when proceeding with a signal, for consistency, neither
1370 do we handle it here (or elsewhere in the file we check for
1371 signal pass state). Normally SIGTRAP isn't set to pass state, so
1372 this is really a corner case. */
1374 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1375 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1376 else if (lp->status)
1377 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1378 else if (non_stop && !is_executing (lp->ptid))
1380 struct thread_info *tp = find_thread_ptid (lp->ptid);
1382 signo = tp->suspend.stop_signal;
1386 struct target_waitstatus last;
1389 get_last_target_status (&last_ptid, &last);
1391 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1393 struct thread_info *tp = find_thread_ptid (lp->ptid);
1395 signo = tp->suspend.stop_signal;
1401 if (signo == GDB_SIGNAL_0)
1403 if (debug_linux_nat)
1404 fprintf_unfiltered (gdb_stdlog,
1405 "GPT: lwp %s has no pending signal\n",
1406 target_pid_to_str (lp->ptid));
1408 else if (!signal_pass_state (signo))
1410 if (debug_linux_nat)
1411 fprintf_unfiltered (gdb_stdlog,
1412 "GPT: lwp %s had signal %s, "
1413 "but it is in no pass state\n",
1414 target_pid_to_str (lp->ptid),
1415 gdb_signal_to_string (signo));
1419 *status = W_STOPCODE (gdb_signal_to_host (signo));
1421 if (debug_linux_nat)
1422 fprintf_unfiltered (gdb_stdlog,
1423 "GPT: lwp %s has pending signal %s\n",
1424 target_pid_to_str (lp->ptid),
1425 gdb_signal_to_string (signo));
1432 detach_callback (struct lwp_info *lp, void *data)
1434 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1436 if (debug_linux_nat && lp->status)
1437 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1438 strsignal (WSTOPSIG (lp->status)),
1439 target_pid_to_str (lp->ptid));
1441 /* If there is a pending SIGSTOP, get rid of it. */
1444 if (debug_linux_nat)
1445 fprintf_unfiltered (gdb_stdlog,
1446 "DC: Sending SIGCONT to %s\n",
1447 target_pid_to_str (lp->ptid));
1449 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1453 /* We don't actually detach from the LWP that has an id equal to the
1454 overall process id just yet. */
1455 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1459 /* Pass on any pending signal for this LWP. */
1460 get_pending_status (lp, &status);
1462 if (linux_nat_prepare_to_resume != NULL)
1463 linux_nat_prepare_to_resume (lp);
1465 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1466 WSTOPSIG (status)) < 0)
1467 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1468 safe_strerror (errno));
1470 if (debug_linux_nat)
1471 fprintf_unfiltered (gdb_stdlog,
1472 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1473 target_pid_to_str (lp->ptid),
1474 strsignal (WSTOPSIG (status)));
1476 delete_lwp (lp->ptid);
1483 linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
1487 struct lwp_info *main_lwp;
1489 pid = ptid_get_pid (inferior_ptid);
1491 /* Don't unregister from the event loop, as there may be other
1492 inferiors running. */
1494 /* Stop all threads before detaching. ptrace requires that the
1495 thread is stopped to sucessfully detach. */
1496 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1497 /* ... and wait until all of them have reported back that
1498 they're no longer running. */
1499 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1501 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1503 /* Only the initial process should be left right now. */
1504 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1506 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1508 /* Pass on any pending signal for the last LWP. */
1509 if ((args == NULL || *args == '\0')
1510 && get_pending_status (main_lwp, &status) != -1
1511 && WIFSTOPPED (status))
1515 /* Put the signal number in ARGS so that inf_ptrace_detach will
1516 pass it along with PTRACE_DETACH. */
1518 xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
1520 if (debug_linux_nat)
1521 fprintf_unfiltered (gdb_stdlog,
1522 "LND: Sending signal %s to %s\n",
1524 target_pid_to_str (main_lwp->ptid));
1527 if (linux_nat_prepare_to_resume != NULL)
1528 linux_nat_prepare_to_resume (main_lwp);
1529 delete_lwp (main_lwp->ptid);
1531 if (forks_exist_p ())
1533 /* Multi-fork case. The current inferior_ptid is being detached
1534 from, but there are other viable forks to debug. Detach from
1535 the current fork, and context-switch to the first
1537 linux_fork_detach (args, from_tty);
1540 linux_ops->to_detach (ops, args, from_tty);
1543 /* Resume execution of the inferior process. If STEP is nonzero,
1544 single-step it. If SIGNAL is nonzero, give it that signal. */
1547 linux_resume_one_lwp_throw (struct lwp_info *lp, int step,
1548 enum gdb_signal signo)
1552 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1553 We only presently need that if the LWP is stepped though (to
1554 handle the case of stepping a breakpoint instruction). */
1557 struct regcache *regcache = get_thread_regcache (lp->ptid);
1559 lp->stop_pc = regcache_read_pc (regcache);
1564 if (linux_nat_prepare_to_resume != NULL)
1565 linux_nat_prepare_to_resume (lp);
1566 linux_ops->to_resume (linux_ops, lp->ptid, step, signo);
1568 /* Successfully resumed. Clear state that no longer makes sense,
1569 and mark the LWP as running. Must not do this before resuming
1570 otherwise if that fails other code will be confused. E.g., we'd
1571 later try to stop the LWP and hang forever waiting for a stop
1572 status. Note that we must not throw after this is cleared,
1573 otherwise handle_zombie_lwp_error would get confused. */
1575 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1576 registers_changed_ptid (lp->ptid);
1579 /* Called when we try to resume a stopped LWP and that errors out. If
1580 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1581 or about to become), discard the error, clear any pending status
1582 the LWP may have, and return true (we'll collect the exit status
1583 soon enough). Otherwise, return false. */
1586 check_ptrace_stopped_lwp_gone (struct lwp_info *lp)
1588 /* If we get an error after resuming the LWP successfully, we'd
1589 confuse !T state for the LWP being gone. */
1590 gdb_assert (lp->stopped);
1592 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1593 because even if ptrace failed with ESRCH, the tracee may be "not
1594 yet fully dead", but already refusing ptrace requests. In that
1595 case the tracee has 'R (Running)' state for a little bit
1596 (observed in Linux 3.18). See also the note on ESRCH in the
1597 ptrace(2) man page. Instead, check whether the LWP has any state
1598 other than ptrace-stopped. */
1600 /* Don't assume anything if /proc/PID/status can't be read. */
1601 if (linux_proc_pid_is_trace_stopped_nowarn (ptid_get_lwp (lp->ptid)) == 0)
1603 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1605 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
1611 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1612 disappears while we try to resume it. */
1615 linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1619 linux_resume_one_lwp_throw (lp, step, signo);
1621 CATCH (ex, RETURN_MASK_ERROR)
1623 if (!check_ptrace_stopped_lwp_gone (lp))
1624 throw_exception (ex);
1632 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1636 struct inferior *inf = find_inferior_ptid (lp->ptid);
1638 if (inf->vfork_child != NULL)
1640 if (debug_linux_nat)
1641 fprintf_unfiltered (gdb_stdlog,
1642 "RC: Not resuming %s (vfork parent)\n",
1643 target_pid_to_str (lp->ptid));
1645 else if (!lwp_status_pending_p (lp))
1647 if (debug_linux_nat)
1648 fprintf_unfiltered (gdb_stdlog,
1649 "RC: Resuming sibling %s, %s, %s\n",
1650 target_pid_to_str (lp->ptid),
1651 (signo != GDB_SIGNAL_0
1652 ? strsignal (gdb_signal_to_host (signo))
1654 step ? "step" : "resume");
1656 linux_resume_one_lwp (lp, step, signo);
1660 if (debug_linux_nat)
1661 fprintf_unfiltered (gdb_stdlog,
1662 "RC: Not resuming sibling %s (has pending)\n",
1663 target_pid_to_str (lp->ptid));
1668 if (debug_linux_nat)
1669 fprintf_unfiltered (gdb_stdlog,
1670 "RC: Not resuming sibling %s (not stopped)\n",
1671 target_pid_to_str (lp->ptid));
1675 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1676 Resume LWP with the last stop signal, if it is in pass state. */
1679 linux_nat_resume_callback (struct lwp_info *lp, void *except)
1681 enum gdb_signal signo = GDB_SIGNAL_0;
1688 struct thread_info *thread;
1690 thread = find_thread_ptid (lp->ptid);
1693 signo = thread->suspend.stop_signal;
1694 thread->suspend.stop_signal = GDB_SIGNAL_0;
1698 resume_lwp (lp, 0, signo);
1703 resume_clear_callback (struct lwp_info *lp, void *data)
1706 lp->last_resume_kind = resume_stop;
1711 resume_set_callback (struct lwp_info *lp, void *data)
1714 lp->last_resume_kind = resume_continue;
1719 linux_nat_resume (struct target_ops *ops,
1720 ptid_t ptid, int step, enum gdb_signal signo)
1722 struct lwp_info *lp;
1725 if (debug_linux_nat)
1726 fprintf_unfiltered (gdb_stdlog,
1727 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1728 step ? "step" : "resume",
1729 target_pid_to_str (ptid),
1730 (signo != GDB_SIGNAL_0
1731 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1732 target_pid_to_str (inferior_ptid));
1734 /* A specific PTID means `step only this process id'. */
1735 resume_many = (ptid_equal (minus_one_ptid, ptid)
1736 || ptid_is_pid (ptid));
1738 /* Mark the lwps we're resuming as resumed. */
1739 iterate_over_lwps (ptid, resume_set_callback, NULL);
1741 /* See if it's the current inferior that should be handled
1744 lp = find_lwp_pid (inferior_ptid);
1746 lp = find_lwp_pid (ptid);
1747 gdb_assert (lp != NULL);
1749 /* Remember if we're stepping. */
1750 lp->last_resume_kind = step ? resume_step : resume_continue;
1752 /* If we have a pending wait status for this thread, there is no
1753 point in resuming the process. But first make sure that
1754 linux_nat_wait won't preemptively handle the event - we
1755 should never take this short-circuit if we are going to
1756 leave LP running, since we have skipped resuming all the
1757 other threads. This bit of code needs to be synchronized
1758 with linux_nat_wait. */
1760 if (lp->status && WIFSTOPPED (lp->status))
1763 && WSTOPSIG (lp->status)
1764 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1766 if (debug_linux_nat)
1767 fprintf_unfiltered (gdb_stdlog,
1768 "LLR: Not short circuiting for ignored "
1769 "status 0x%x\n", lp->status);
1771 /* FIXME: What should we do if we are supposed to continue
1772 this thread with a signal? */
1773 gdb_assert (signo == GDB_SIGNAL_0);
1774 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1779 if (lwp_status_pending_p (lp))
1781 /* FIXME: What should we do if we are supposed to continue
1782 this thread with a signal? */
1783 gdb_assert (signo == GDB_SIGNAL_0);
1785 if (debug_linux_nat)
1786 fprintf_unfiltered (gdb_stdlog,
1787 "LLR: Short circuiting for status 0x%x\n",
1790 if (target_can_async_p ())
1793 /* Tell the event loop we have something to process. */
1800 iterate_over_lwps (ptid, linux_nat_resume_callback, lp);
1802 if (debug_linux_nat)
1803 fprintf_unfiltered (gdb_stdlog,
1804 "LLR: %s %s, %s (resume event thread)\n",
1805 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1806 target_pid_to_str (lp->ptid),
1807 (signo != GDB_SIGNAL_0
1808 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1810 linux_resume_one_lwp (lp, step, signo);
1812 if (target_can_async_p ())
1816 /* Send a signal to an LWP. */
1819 kill_lwp (int lwpid, int signo)
1821 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1822 fails, then we are not using nptl threads and we should be using kill. */
1824 #ifdef HAVE_TKILL_SYSCALL
1826 static int tkill_failed;
1833 ret = syscall (__NR_tkill, lwpid, signo);
1834 if (errno != ENOSYS)
1841 return kill (lwpid, signo);
1844 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1845 event, check if the core is interested in it: if not, ignore the
1846 event, and keep waiting; otherwise, we need to toggle the LWP's
1847 syscall entry/exit status, since the ptrace event itself doesn't
1848 indicate it, and report the trap to higher layers. */
1851 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1853 struct target_waitstatus *ourstatus = &lp->waitstatus;
1854 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1855 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1859 /* If we're stopping threads, there's a SIGSTOP pending, which
1860 makes it so that the LWP reports an immediate syscall return,
1861 followed by the SIGSTOP. Skip seeing that "return" using
1862 PTRACE_CONT directly, and let stop_wait_callback collect the
1863 SIGSTOP. Later when the thread is resumed, a new syscall
1864 entry event. If we didn't do this (and returned 0), we'd
1865 leave a syscall entry pending, and our caller, by using
1866 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1867 itself. Later, when the user re-resumes this LWP, we'd see
1868 another syscall entry event and we'd mistake it for a return.
1870 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1871 (leaving immediately with LWP->signalled set, without issuing
1872 a PTRACE_CONT), it would still be problematic to leave this
1873 syscall enter pending, as later when the thread is resumed,
1874 it would then see the same syscall exit mentioned above,
1875 followed by the delayed SIGSTOP, while the syscall didn't
1876 actually get to execute. It seems it would be even more
1877 confusing to the user. */
1879 if (debug_linux_nat)
1880 fprintf_unfiltered (gdb_stdlog,
1881 "LHST: ignoring syscall %d "
1882 "for LWP %ld (stopping threads), "
1883 "resuming with PTRACE_CONT for SIGSTOP\n",
1885 ptid_get_lwp (lp->ptid));
1887 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1888 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1893 if (catch_syscall_enabled ())
1895 /* Always update the entry/return state, even if this particular
1896 syscall isn't interesting to the core now. In async mode,
1897 the user could install a new catchpoint for this syscall
1898 between syscall enter/return, and we'll need to know to
1899 report a syscall return if that happens. */
1900 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1901 ? TARGET_WAITKIND_SYSCALL_RETURN
1902 : TARGET_WAITKIND_SYSCALL_ENTRY);
1904 if (catching_syscall_number (syscall_number))
1906 /* Alright, an event to report. */
1907 ourstatus->kind = lp->syscall_state;
1908 ourstatus->value.syscall_number = syscall_number;
1910 if (debug_linux_nat)
1911 fprintf_unfiltered (gdb_stdlog,
1912 "LHST: stopping for %s of syscall %d"
1915 == TARGET_WAITKIND_SYSCALL_ENTRY
1916 ? "entry" : "return",
1918 ptid_get_lwp (lp->ptid));
1922 if (debug_linux_nat)
1923 fprintf_unfiltered (gdb_stdlog,
1924 "LHST: ignoring %s of syscall %d "
1926 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1927 ? "entry" : "return",
1929 ptid_get_lwp (lp->ptid));
1933 /* If we had been syscall tracing, and hence used PT_SYSCALL
1934 before on this LWP, it could happen that the user removes all
1935 syscall catchpoints before we get to process this event.
1936 There are two noteworthy issues here:
1938 - When stopped at a syscall entry event, resuming with
1939 PT_STEP still resumes executing the syscall and reports a
1942 - Only PT_SYSCALL catches syscall enters. If we last
1943 single-stepped this thread, then this event can't be a
1944 syscall enter. If we last single-stepped this thread, this
1945 has to be a syscall exit.
1947 The points above mean that the next resume, be it PT_STEP or
1948 PT_CONTINUE, can not trigger a syscall trace event. */
1949 if (debug_linux_nat)
1950 fprintf_unfiltered (gdb_stdlog,
1951 "LHST: caught syscall event "
1952 "with no syscall catchpoints."
1953 " %d for LWP %ld, ignoring\n",
1955 ptid_get_lwp (lp->ptid));
1956 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1959 /* The core isn't interested in this event. For efficiency, avoid
1960 stopping all threads only to have the core resume them all again.
1961 Since we're not stopping threads, if we're still syscall tracing
1962 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1963 subsequent syscall. Simply resume using the inf-ptrace layer,
1964 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1966 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
1970 /* Handle a GNU/Linux extended wait response. If we see a clone
1971 event, we need to add the new LWP to our list (and not report the
1972 trap to higher layers). This function returns non-zero if the
1973 event should be ignored and we should wait again. If STOPPING is
1974 true, the new LWP remains stopped, otherwise it is continued. */
1977 linux_handle_extended_wait (struct lwp_info *lp, int status,
1980 int pid = ptid_get_lwp (lp->ptid);
1981 struct target_waitstatus *ourstatus = &lp->waitstatus;
1982 int event = linux_ptrace_get_extended_event (status);
1984 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1985 || event == PTRACE_EVENT_CLONE)
1987 unsigned long new_pid;
1990 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
1992 /* If we haven't already seen the new PID stop, wait for it now. */
1993 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
1995 /* The new child has a pending SIGSTOP. We can't affect it until it
1996 hits the SIGSTOP, but we're already attached. */
1997 ret = my_waitpid (new_pid, &status,
1998 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
2000 perror_with_name (_("waiting for new child"));
2001 else if (ret != new_pid)
2002 internal_error (__FILE__, __LINE__,
2003 _("wait returned unexpected PID %d"), ret);
2004 else if (!WIFSTOPPED (status))
2005 internal_error (__FILE__, __LINE__,
2006 _("wait returned unexpected status 0x%x"), status);
2009 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
2011 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
2013 /* The arch-specific native code may need to know about new
2014 forks even if those end up never mapped to an
2016 if (linux_nat_new_fork != NULL)
2017 linux_nat_new_fork (lp, new_pid);
2020 if (event == PTRACE_EVENT_FORK
2021 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
2023 /* Handle checkpointing by linux-fork.c here as a special
2024 case. We don't want the follow-fork-mode or 'catch fork'
2025 to interfere with this. */
2027 /* This won't actually modify the breakpoint list, but will
2028 physically remove the breakpoints from the child. */
2029 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
2031 /* Retain child fork in ptrace (stopped) state. */
2032 if (!find_fork_pid (new_pid))
2035 /* Report as spurious, so that infrun doesn't want to follow
2036 this fork. We're actually doing an infcall in
2038 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
2040 /* Report the stop to the core. */
2044 if (event == PTRACE_EVENT_FORK)
2045 ourstatus->kind = TARGET_WAITKIND_FORKED;
2046 else if (event == PTRACE_EVENT_VFORK)
2047 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2050 struct lwp_info *new_lp;
2052 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2054 if (debug_linux_nat)
2055 fprintf_unfiltered (gdb_stdlog,
2056 "LHEW: Got clone event "
2057 "from LWP %d, new child is LWP %ld\n",
2060 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
2062 new_lp->stopped = 1;
2064 if (WSTOPSIG (status) != SIGSTOP)
2066 /* This can happen if someone starts sending signals to
2067 the new thread before it gets a chance to run, which
2068 have a lower number than SIGSTOP (e.g. SIGUSR1).
2069 This is an unlikely case, and harder to handle for
2070 fork / vfork than for clone, so we do not try - but
2071 we handle it for clone events here. We'll send
2072 the other signal on to the thread below. */
2074 new_lp->signalled = 1;
2078 struct thread_info *tp;
2080 /* When we stop for an event in some other thread, and
2081 pull the thread list just as this thread has cloned,
2082 we'll have seen the new thread in the thread_db list
2083 before handling the CLONE event (glibc's
2084 pthread_create adds the new thread to the thread list
2085 before clone'ing, and has the kernel fill in the
2086 thread's tid on the clone call with
2087 CLONE_PARENT_SETTID). If that happened, and the core
2088 had requested the new thread to stop, we'll have
2089 killed it with SIGSTOP. But since SIGSTOP is not an
2090 RT signal, it can only be queued once. We need to be
2091 careful to not resume the LWP if we wanted it to
2092 stop. In that case, we'll leave the SIGSTOP pending.
2093 It will later be reported as GDB_SIGNAL_0. */
2094 tp = find_thread_ptid (new_lp->ptid);
2095 if (tp != NULL && tp->stop_requested)
2096 new_lp->last_resume_kind = resume_stop;
2101 /* If the thread_db layer is active, let it record the user
2102 level thread id and status, and add the thread to GDB's
2104 if (!thread_db_notice_clone (lp->ptid, new_lp->ptid))
2106 /* The process is not using thread_db. Add the LWP to
2108 target_post_attach (ptid_get_lwp (new_lp->ptid));
2109 add_thread (new_lp->ptid);
2112 /* Even if we're stopping the thread for some reason
2113 internal to this module, from the user/frontend's
2114 perspective, this new thread is running. */
2115 set_running (new_lp->ptid, 1);
2118 set_executing (new_lp->ptid, 1);
2119 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2121 new_lp->last_resume_kind = resume_continue;
2126 /* We created NEW_LP so it cannot yet contain STATUS. */
2127 gdb_assert (new_lp->status == 0);
2129 /* Save the wait status to report later. */
2130 if (debug_linux_nat)
2131 fprintf_unfiltered (gdb_stdlog,
2132 "LHEW: waitpid of new LWP %ld, "
2133 "saving status %s\n",
2134 (long) ptid_get_lwp (new_lp->ptid),
2135 status_to_str (status));
2136 new_lp->status = status;
2139 new_lp->resumed = !stopping;
2146 if (event == PTRACE_EVENT_EXEC)
2148 if (debug_linux_nat)
2149 fprintf_unfiltered (gdb_stdlog,
2150 "LHEW: Got exec event from LWP %ld\n",
2151 ptid_get_lwp (lp->ptid));
2153 ourstatus->kind = TARGET_WAITKIND_EXECD;
2154 ourstatus->value.execd_pathname
2155 = xstrdup (linux_child_pid_to_exec_file (NULL, pid));
2157 /* The thread that execed must have been resumed, but, when a
2158 thread execs, it changes its tid to the tgid, and the old
2159 tgid thread might have not been resumed. */
2164 if (event == PTRACE_EVENT_VFORK_DONE)
2166 if (current_inferior ()->waiting_for_vfork_done)
2168 if (debug_linux_nat)
2169 fprintf_unfiltered (gdb_stdlog,
2170 "LHEW: Got expected PTRACE_EVENT_"
2171 "VFORK_DONE from LWP %ld: stopping\n",
2172 ptid_get_lwp (lp->ptid));
2174 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2178 if (debug_linux_nat)
2179 fprintf_unfiltered (gdb_stdlog,
2180 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2181 "from LWP %ld: ignoring\n",
2182 ptid_get_lwp (lp->ptid));
2186 internal_error (__FILE__, __LINE__,
2187 _("unknown ptrace event %d"), event);
2190 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2194 wait_lwp (struct lwp_info *lp)
2198 int thread_dead = 0;
2201 gdb_assert (!lp->stopped);
2202 gdb_assert (lp->status == 0);
2204 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2205 block_child_signals (&prev_mask);
2209 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2210 was right and we should just call sigsuspend. */
2212 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2213 if (pid == -1 && errno == ECHILD)
2214 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2215 if (pid == -1 && errno == ECHILD)
2217 /* The thread has previously exited. We need to delete it
2218 now because, for some vendor 2.4 kernels with NPTL
2219 support backported, there won't be an exit event unless
2220 it is the main thread. 2.6 kernels will report an exit
2221 event for each thread that exits, as expected. */
2223 if (debug_linux_nat)
2224 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2225 target_pid_to_str (lp->ptid));
2230 /* Bugs 10970, 12702.
2231 Thread group leader may have exited in which case we'll lock up in
2232 waitpid if there are other threads, even if they are all zombies too.
2233 Basically, we're not supposed to use waitpid this way.
2234 __WCLONE is not applicable for the leader so we can't use that.
2235 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2236 process; it gets ESRCH both for the zombie and for running processes.
2238 As a workaround, check if we're waiting for the thread group leader and
2239 if it's a zombie, and avoid calling waitpid if it is.
2241 This is racy, what if the tgl becomes a zombie right after we check?
2242 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2243 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2245 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2246 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2249 if (debug_linux_nat)
2250 fprintf_unfiltered (gdb_stdlog,
2251 "WL: Thread group leader %s vanished.\n",
2252 target_pid_to_str (lp->ptid));
2256 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2257 get invoked despite our caller had them intentionally blocked by
2258 block_child_signals. This is sensitive only to the loop of
2259 linux_nat_wait_1 and there if we get called my_waitpid gets called
2260 again before it gets to sigsuspend so we can safely let the handlers
2261 get executed here. */
2263 if (debug_linux_nat)
2264 fprintf_unfiltered (gdb_stdlog, "WL: about to sigsuspend\n");
2265 sigsuspend (&suspend_mask);
2268 restore_child_signals_mask (&prev_mask);
2272 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2274 if (debug_linux_nat)
2276 fprintf_unfiltered (gdb_stdlog,
2277 "WL: waitpid %s received %s\n",
2278 target_pid_to_str (lp->ptid),
2279 status_to_str (status));
2282 /* Check if the thread has exited. */
2283 if (WIFEXITED (status) || WIFSIGNALED (status))
2286 if (debug_linux_nat)
2287 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2288 target_pid_to_str (lp->ptid));
2298 gdb_assert (WIFSTOPPED (status));
2301 if (lp->must_set_ptrace_flags)
2303 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2305 linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
2306 lp->must_set_ptrace_flags = 0;
2309 /* Handle GNU/Linux's syscall SIGTRAPs. */
2310 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2312 /* No longer need the sysgood bit. The ptrace event ends up
2313 recorded in lp->waitstatus if we care for it. We can carry
2314 on handling the event like a regular SIGTRAP from here
2316 status = W_STOPCODE (SIGTRAP);
2317 if (linux_handle_syscall_trap (lp, 1))
2318 return wait_lwp (lp);
2321 /* Handle GNU/Linux's extended waitstatus for trace events. */
2322 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
2323 && linux_is_extended_waitstatus (status))
2325 if (debug_linux_nat)
2326 fprintf_unfiltered (gdb_stdlog,
2327 "WL: Handling extended status 0x%06x\n",
2329 linux_handle_extended_wait (lp, status, 1);
2336 /* Send a SIGSTOP to LP. */
2339 stop_callback (struct lwp_info *lp, void *data)
2341 if (!lp->stopped && !lp->signalled)
2345 if (debug_linux_nat)
2347 fprintf_unfiltered (gdb_stdlog,
2348 "SC: kill %s **<SIGSTOP>**\n",
2349 target_pid_to_str (lp->ptid));
2352 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2353 if (debug_linux_nat)
2355 fprintf_unfiltered (gdb_stdlog,
2356 "SC: lwp kill %d %s\n",
2358 errno ? safe_strerror (errno) : "ERRNO-OK");
2362 gdb_assert (lp->status == 0);
2368 /* Request a stop on LWP. */
2371 linux_stop_lwp (struct lwp_info *lwp)
2373 stop_callback (lwp, NULL);
2376 /* See linux-nat.h */
2379 linux_stop_and_wait_all_lwps (void)
2381 /* Stop all LWP's ... */
2382 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
2384 /* ... and wait until all of them have reported back that
2385 they're no longer running. */
2386 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
2389 /* See linux-nat.h */
2392 linux_unstop_all_lwps (void)
2394 iterate_over_lwps (minus_one_ptid,
2395 resume_stopped_resumed_lwps, &minus_one_ptid);
2398 /* Return non-zero if LWP PID has a pending SIGINT. */
2401 linux_nat_has_pending_sigint (int pid)
2403 sigset_t pending, blocked, ignored;
2405 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2407 if (sigismember (&pending, SIGINT)
2408 && !sigismember (&ignored, SIGINT))
2414 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2417 set_ignore_sigint (struct lwp_info *lp, void *data)
2419 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2420 flag to consume the next one. */
2421 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2422 && WSTOPSIG (lp->status) == SIGINT)
2425 lp->ignore_sigint = 1;
2430 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2431 This function is called after we know the LWP has stopped; if the LWP
2432 stopped before the expected SIGINT was delivered, then it will never have
2433 arrived. Also, if the signal was delivered to a shared queue and consumed
2434 by a different thread, it will never be delivered to this LWP. */
2437 maybe_clear_ignore_sigint (struct lwp_info *lp)
2439 if (!lp->ignore_sigint)
2442 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2444 if (debug_linux_nat)
2445 fprintf_unfiltered (gdb_stdlog,
2446 "MCIS: Clearing bogus flag for %s\n",
2447 target_pid_to_str (lp->ptid));
2448 lp->ignore_sigint = 0;
2452 /* Fetch the possible triggered data watchpoint info and store it in
2455 On some archs, like x86, that use debug registers to set
2456 watchpoints, it's possible that the way to know which watched
2457 address trapped, is to check the register that is used to select
2458 which address to watch. Problem is, between setting the watchpoint
2459 and reading back which data address trapped, the user may change
2460 the set of watchpoints, and, as a consequence, GDB changes the
2461 debug registers in the inferior. To avoid reading back a stale
2462 stopped-data-address when that happens, we cache in LP the fact
2463 that a watchpoint trapped, and the corresponding data address, as
2464 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2465 registers meanwhile, we have the cached data we can rely on. */
2468 check_stopped_by_watchpoint (struct lwp_info *lp)
2470 struct cleanup *old_chain;
2472 if (linux_ops->to_stopped_by_watchpoint == NULL)
2475 old_chain = save_inferior_ptid ();
2476 inferior_ptid = lp->ptid;
2478 if (linux_ops->to_stopped_by_watchpoint (linux_ops))
2480 lp->stop_reason = TARGET_STOPPED_BY_WATCHPOINT;
2482 if (linux_ops->to_stopped_data_address != NULL)
2483 lp->stopped_data_address_p =
2484 linux_ops->to_stopped_data_address (¤t_target,
2485 &lp->stopped_data_address);
2487 lp->stopped_data_address_p = 0;
2490 do_cleanups (old_chain);
2492 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2495 /* Called when the LWP stopped for a trap that could be explained by a
2496 watchpoint or a breakpoint. */
2499 save_sigtrap (struct lwp_info *lp)
2501 gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
2502 gdb_assert (lp->status != 0);
2504 /* Check first if this was a SW/HW breakpoint before checking
2505 watchpoints, because at least s390 can't tell the data address of
2506 hardware watchpoint hits, and the kernel returns
2507 stopped-by-watchpoint as long as there's a watchpoint set. */
2508 if (linux_nat_status_is_event (lp->status))
2509 check_stopped_by_breakpoint (lp);
2511 /* Note that TRAP_HWBKPT can indicate either a hardware breakpoint
2512 or hardware watchpoint. Check which is which if we got
2513 TARGET_STOPPED_BY_HW_BREAKPOINT. */
2514 if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON
2515 || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2516 check_stopped_by_watchpoint (lp);
2519 /* Returns true if the LWP had stopped for a watchpoint. */
2522 linux_nat_stopped_by_watchpoint (struct target_ops *ops)
2524 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2526 gdb_assert (lp != NULL);
2528 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2532 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2534 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2536 gdb_assert (lp != NULL);
2538 *addr_p = lp->stopped_data_address;
2540 return lp->stopped_data_address_p;
2543 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2546 sigtrap_is_event (int status)
2548 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2551 /* Set alternative SIGTRAP-like events recognizer. If
2552 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2556 linux_nat_set_status_is_event (struct target_ops *t,
2557 int (*status_is_event) (int status))
2559 linux_nat_status_is_event = status_is_event;
2562 /* Wait until LP is stopped. */
2565 stop_wait_callback (struct lwp_info *lp, void *data)
2567 struct inferior *inf = find_inferior_ptid (lp->ptid);
2569 /* If this is a vfork parent, bail out, it is not going to report
2570 any SIGSTOP until the vfork is done with. */
2571 if (inf->vfork_child != NULL)
2578 status = wait_lwp (lp);
2582 if (lp->ignore_sigint && WIFSTOPPED (status)
2583 && WSTOPSIG (status) == SIGINT)
2585 lp->ignore_sigint = 0;
2588 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2590 if (debug_linux_nat)
2591 fprintf_unfiltered (gdb_stdlog,
2592 "PTRACE_CONT %s, 0, 0 (%s) "
2593 "(discarding SIGINT)\n",
2594 target_pid_to_str (lp->ptid),
2595 errno ? safe_strerror (errno) : "OK");
2597 return stop_wait_callback (lp, NULL);
2600 maybe_clear_ignore_sigint (lp);
2602 if (WSTOPSIG (status) != SIGSTOP)
2604 /* The thread was stopped with a signal other than SIGSTOP. */
2606 if (debug_linux_nat)
2607 fprintf_unfiltered (gdb_stdlog,
2608 "SWC: Pending event %s in %s\n",
2609 status_to_str ((int) status),
2610 target_pid_to_str (lp->ptid));
2612 /* Save the sigtrap event. */
2613 lp->status = status;
2614 gdb_assert (lp->signalled);
2619 /* We caught the SIGSTOP that we intended to catch, so
2620 there's no SIGSTOP pending. */
2622 if (debug_linux_nat)
2623 fprintf_unfiltered (gdb_stdlog,
2624 "SWC: Expected SIGSTOP caught for %s.\n",
2625 target_pid_to_str (lp->ptid));
2627 /* Reset SIGNALLED only after the stop_wait_callback call
2628 above as it does gdb_assert on SIGNALLED. */
2636 /* Return non-zero if LP has a wait status pending. Discard the
2637 pending event and resume the LWP if the event that originally
2638 caused the stop became uninteresting. */
2641 status_callback (struct lwp_info *lp, void *data)
2643 /* Only report a pending wait status if we pretend that this has
2644 indeed been resumed. */
2648 if (!lwp_status_pending_p (lp))
2651 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
2652 || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2654 struct regcache *regcache = get_thread_regcache (lp->ptid);
2655 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2659 pc = regcache_read_pc (regcache);
2661 if (pc != lp->stop_pc)
2663 if (debug_linux_nat)
2664 fprintf_unfiltered (gdb_stdlog,
2665 "SC: PC of %s changed. was=%s, now=%s\n",
2666 target_pid_to_str (lp->ptid),
2667 paddress (target_gdbarch (), lp->stop_pc),
2668 paddress (target_gdbarch (), pc));
2672 #if !USE_SIGTRAP_SIGINFO
2673 else if (!breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2675 if (debug_linux_nat)
2676 fprintf_unfiltered (gdb_stdlog,
2677 "SC: previous breakpoint of %s, at %s gone\n",
2678 target_pid_to_str (lp->ptid),
2679 paddress (target_gdbarch (), lp->stop_pc));
2687 if (debug_linux_nat)
2688 fprintf_unfiltered (gdb_stdlog,
2689 "SC: pending event of %s cancelled.\n",
2690 target_pid_to_str (lp->ptid));
2693 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
2701 /* Return non-zero if LP isn't stopped. */
2704 running_callback (struct lwp_info *lp, void *data)
2706 return (!lp->stopped
2707 || (lwp_status_pending_p (lp) && lp->resumed));
2710 /* Count the LWP's that have had events. */
2713 count_events_callback (struct lwp_info *lp, void *data)
2717 gdb_assert (count != NULL);
2719 /* Select only resumed LWPs that have an event pending. */
2720 if (lp->resumed && lwp_status_pending_p (lp))
2726 /* Select the LWP (if any) that is currently being single-stepped. */
2729 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2731 if (lp->last_resume_kind == resume_step
2738 /* Returns true if LP has a status pending. */
2741 lwp_status_pending_p (struct lwp_info *lp)
2743 /* We check for lp->waitstatus in addition to lp->status, because we
2744 can have pending process exits recorded in lp->status and
2745 W_EXITCODE(0,0) happens to be 0. */
2746 return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE;
2749 /* Select the Nth LWP that has had an event. */
2752 select_event_lwp_callback (struct lwp_info *lp, void *data)
2754 int *selector = data;
2756 gdb_assert (selector != NULL);
2758 /* Select only resumed LWPs that have an event pending. */
2759 if (lp->resumed && lwp_status_pending_p (lp))
2760 if ((*selector)-- == 0)
2766 /* Called when the LWP got a signal/trap that could be explained by a
2767 software or hardware breakpoint. */
2770 check_stopped_by_breakpoint (struct lwp_info *lp)
2772 /* Arrange for a breakpoint to be hit again later. We don't keep
2773 the SIGTRAP status and don't forward the SIGTRAP signal to the
2774 LWP. We will handle the current event, eventually we will resume
2775 this LWP, and this breakpoint will trap again.
2777 If we do not do this, then we run the risk that the user will
2778 delete or disable the breakpoint, but the LWP will have already
2781 struct regcache *regcache = get_thread_regcache (lp->ptid);
2782 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2785 #if USE_SIGTRAP_SIGINFO
2789 pc = regcache_read_pc (regcache);
2790 sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch);
2792 #if USE_SIGTRAP_SIGINFO
2793 if (linux_nat_get_siginfo (lp->ptid, &siginfo))
2795 if (siginfo.si_signo == SIGTRAP)
2797 if (siginfo.si_code == GDB_ARCH_TRAP_BRKPT)
2799 if (debug_linux_nat)
2800 fprintf_unfiltered (gdb_stdlog,
2801 "CSBB: %s stopped by software "
2803 target_pid_to_str (lp->ptid));
2805 /* Back up the PC if necessary. */
2807 regcache_write_pc (regcache, sw_bp_pc);
2809 lp->stop_pc = sw_bp_pc;
2810 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2813 else if (siginfo.si_code == TRAP_HWBKPT)
2815 if (debug_linux_nat)
2816 fprintf_unfiltered (gdb_stdlog,
2817 "CSBB: %s stopped by hardware "
2818 "breakpoint/watchpoint\n",
2819 target_pid_to_str (lp->ptid));
2822 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2825 else if (siginfo.si_code == TRAP_TRACE)
2827 if (debug_linux_nat)
2828 fprintf_unfiltered (gdb_stdlog,
2829 "CSBB: %s stopped by trace\n",
2830 target_pid_to_str (lp->ptid));
2835 if ((!lp->step || lp->stop_pc == sw_bp_pc)
2836 && software_breakpoint_inserted_here_p (get_regcache_aspace (regcache),
2839 /* The LWP was either continued, or stepped a software
2840 breakpoint instruction. */
2841 if (debug_linux_nat)
2842 fprintf_unfiltered (gdb_stdlog,
2843 "CSBB: %s stopped by software breakpoint\n",
2844 target_pid_to_str (lp->ptid));
2846 /* Back up the PC if necessary. */
2848 regcache_write_pc (regcache, sw_bp_pc);
2850 lp->stop_pc = sw_bp_pc;
2851 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2855 if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2857 if (debug_linux_nat)
2858 fprintf_unfiltered (gdb_stdlog,
2859 "CSBB: stopped by hardware breakpoint %s\n",
2860 target_pid_to_str (lp->ptid));
2863 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2872 /* Returns true if the LWP had stopped for a software breakpoint. */
2875 linux_nat_stopped_by_sw_breakpoint (struct target_ops *ops)
2877 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2879 gdb_assert (lp != NULL);
2881 return lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT;
2884 /* Implement the supports_stopped_by_sw_breakpoint method. */
2887 linux_nat_supports_stopped_by_sw_breakpoint (struct target_ops *ops)
2889 return USE_SIGTRAP_SIGINFO;
2892 /* Returns true if the LWP had stopped for a hardware
2893 breakpoint/watchpoint. */
2896 linux_nat_stopped_by_hw_breakpoint (struct target_ops *ops)
2898 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2900 gdb_assert (lp != NULL);
2902 return lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT;
2905 /* Implement the supports_stopped_by_hw_breakpoint method. */
2908 linux_nat_supports_stopped_by_hw_breakpoint (struct target_ops *ops)
2910 return USE_SIGTRAP_SIGINFO;
2913 /* Select one LWP out of those that have events pending. */
2916 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2919 int random_selector;
2920 struct lwp_info *event_lp = NULL;
2922 /* Record the wait status for the original LWP. */
2923 (*orig_lp)->status = *status;
2925 /* In all-stop, give preference to the LWP that is being
2926 single-stepped. There will be at most one, and it will be the
2927 LWP that the core is most interested in. If we didn't do this,
2928 then we'd have to handle pending step SIGTRAPs somehow in case
2929 the core later continues the previously-stepped thread, as
2930 otherwise we'd report the pending SIGTRAP then, and the core, not
2931 having stepped the thread, wouldn't understand what the trap was
2932 for, and therefore would report it to the user as a random
2936 event_lp = iterate_over_lwps (filter,
2937 select_singlestep_lwp_callback, NULL);
2938 if (event_lp != NULL)
2940 if (debug_linux_nat)
2941 fprintf_unfiltered (gdb_stdlog,
2942 "SEL: Select single-step %s\n",
2943 target_pid_to_str (event_lp->ptid));
2947 if (event_lp == NULL)
2949 /* Pick one at random, out of those which have had events. */
2951 /* First see how many events we have. */
2952 iterate_over_lwps (filter, count_events_callback, &num_events);
2953 gdb_assert (num_events > 0);
2955 /* Now randomly pick a LWP out of those that have had
2957 random_selector = (int)
2958 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2960 if (debug_linux_nat && num_events > 1)
2961 fprintf_unfiltered (gdb_stdlog,
2962 "SEL: Found %d events, selecting #%d\n",
2963 num_events, random_selector);
2965 event_lp = iterate_over_lwps (filter,
2966 select_event_lwp_callback,
2970 if (event_lp != NULL)
2972 /* Switch the event LWP. */
2973 *orig_lp = event_lp;
2974 *status = event_lp->status;
2977 /* Flush the wait status for the event LWP. */
2978 (*orig_lp)->status = 0;
2981 /* Return non-zero if LP has been resumed. */
2984 resumed_callback (struct lwp_info *lp, void *data)
2989 /* Stop an active thread, verify it still exists, then resume it. If
2990 the thread ends up with a pending status, then it is not resumed,
2991 and *DATA (really a pointer to int), is set. */
2994 stop_and_resume_callback (struct lwp_info *lp, void *data)
2998 ptid_t ptid = lp->ptid;
3000 stop_callback (lp, NULL);
3001 stop_wait_callback (lp, NULL);
3003 /* Resume if the lwp still exists, and the core wanted it
3005 lp = find_lwp_pid (ptid);
3008 if (lp->last_resume_kind == resume_stop
3009 && !lwp_status_pending_p (lp))
3011 /* The core wanted the LWP to stop. Even if it stopped
3012 cleanly (with SIGSTOP), leave the event pending. */
3013 if (debug_linux_nat)
3014 fprintf_unfiltered (gdb_stdlog,
3015 "SARC: core wanted LWP %ld stopped "
3016 "(leaving SIGSTOP pending)\n",
3017 ptid_get_lwp (lp->ptid));
3018 lp->status = W_STOPCODE (SIGSTOP);
3021 if (!lwp_status_pending_p (lp))
3023 if (debug_linux_nat)
3024 fprintf_unfiltered (gdb_stdlog,
3025 "SARC: re-resuming LWP %ld\n",
3026 ptid_get_lwp (lp->ptid));
3027 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
3031 if (debug_linux_nat)
3032 fprintf_unfiltered (gdb_stdlog,
3033 "SARC: not re-resuming LWP %ld "
3035 ptid_get_lwp (lp->ptid));
3042 /* Check if we should go on and pass this event to common code.
3043 Return the affected lwp if we are, or NULL otherwise. */
3045 static struct lwp_info *
3046 linux_nat_filter_event (int lwpid, int status)
3048 struct lwp_info *lp;
3049 int event = linux_ptrace_get_extended_event (status);
3051 lp = find_lwp_pid (pid_to_ptid (lwpid));
3053 /* Check for stop events reported by a process we didn't already
3054 know about - anything not already in our LWP list.
3056 If we're expecting to receive stopped processes after
3057 fork, vfork, and clone events, then we'll just add the
3058 new one to our list and go back to waiting for the event
3059 to be reported - the stopped process might be returned
3060 from waitpid before or after the event is.
3062 But note the case of a non-leader thread exec'ing after the
3063 leader having exited, and gone from our lists. The non-leader
3064 thread changes its tid to the tgid. */
3066 if (WIFSTOPPED (status) && lp == NULL
3067 && (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
3069 /* A multi-thread exec after we had seen the leader exiting. */
3070 if (debug_linux_nat)
3071 fprintf_unfiltered (gdb_stdlog,
3072 "LLW: Re-adding thread group leader LWP %d.\n",
3075 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
3078 add_thread (lp->ptid);
3081 if (WIFSTOPPED (status) && !lp)
3083 if (debug_linux_nat)
3084 fprintf_unfiltered (gdb_stdlog,
3085 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
3086 (long) lwpid, status_to_str (status));
3087 add_to_pid_list (&stopped_pids, lwpid, status);
3091 /* Make sure we don't report an event for the exit of an LWP not in
3092 our list, i.e. not part of the current process. This can happen
3093 if we detach from a program we originally forked and then it
3095 if (!WIFSTOPPED (status) && !lp)
3098 /* This LWP is stopped now. (And if dead, this prevents it from
3099 ever being continued.) */
3102 if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
3104 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
3106 linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
3107 lp->must_set_ptrace_flags = 0;
3110 /* Handle GNU/Linux's syscall SIGTRAPs. */
3111 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
3113 /* No longer need the sysgood bit. The ptrace event ends up
3114 recorded in lp->waitstatus if we care for it. We can carry
3115 on handling the event like a regular SIGTRAP from here
3117 status = W_STOPCODE (SIGTRAP);
3118 if (linux_handle_syscall_trap (lp, 0))
3122 /* Handle GNU/Linux's extended waitstatus for trace events. */
3123 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
3124 && linux_is_extended_waitstatus (status))
3126 if (debug_linux_nat)
3127 fprintf_unfiltered (gdb_stdlog,
3128 "LLW: Handling extended status 0x%06x\n",
3130 if (linux_handle_extended_wait (lp, status, 0))
3134 /* Check if the thread has exited. */
3135 if (WIFEXITED (status) || WIFSIGNALED (status))
3137 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3139 /* If this is the main thread, we must stop all threads and
3140 verify if they are still alive. This is because in the
3141 nptl thread model on Linux 2.4, there is no signal issued
3142 for exiting LWPs other than the main thread. We only get
3143 the main thread exit signal once all child threads have
3144 already exited. If we stop all the threads and use the
3145 stop_wait_callback to check if they have exited we can
3146 determine whether this signal should be ignored or
3147 whether it means the end of the debugged application,
3148 regardless of which threading model is being used. */
3149 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
3151 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3152 stop_and_resume_callback, NULL);
3155 if (debug_linux_nat)
3156 fprintf_unfiltered (gdb_stdlog,
3157 "LLW: %s exited.\n",
3158 target_pid_to_str (lp->ptid));
3160 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3162 /* If there is at least one more LWP, then the exit signal
3163 was not the end of the debugged application and should be
3170 gdb_assert (lp->resumed);
3172 if (debug_linux_nat)
3173 fprintf_unfiltered (gdb_stdlog,
3174 "Process %ld exited\n",
3175 ptid_get_lwp (lp->ptid));
3177 /* This was the last lwp in the process. Since events are
3178 serialized to GDB core, we may not be able report this one
3179 right now, but GDB core and the other target layers will want
3180 to be notified about the exit code/signal, leave the status
3181 pending for the next time we're able to report it. */
3183 /* Dead LWP's aren't expected to reported a pending sigstop. */
3186 /* Store the pending event in the waitstatus, because
3187 W_EXITCODE(0,0) == 0. */
3188 store_waitstatus (&lp->waitstatus, status);
3192 /* Check if the current LWP has previously exited. In the nptl
3193 thread model, LWPs other than the main thread do not issue
3194 signals when they exit so we must check whenever the thread has
3195 stopped. A similar check is made in stop_wait_callback(). */
3196 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3198 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3200 if (debug_linux_nat)
3201 fprintf_unfiltered (gdb_stdlog,
3202 "LLW: %s exited.\n",
3203 target_pid_to_str (lp->ptid));
3207 /* Make sure there is at least one thread running. */
3208 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3210 /* Discard the event. */
3214 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3215 an attempt to stop an LWP. */
3217 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3221 if (lp->last_resume_kind == resume_stop)
3223 if (debug_linux_nat)
3224 fprintf_unfiltered (gdb_stdlog,
3225 "LLW: resume_stop SIGSTOP caught for %s.\n",
3226 target_pid_to_str (lp->ptid));
3230 /* This is a delayed SIGSTOP. Filter out the event. */
3232 if (debug_linux_nat)
3233 fprintf_unfiltered (gdb_stdlog,
3234 "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
3236 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3237 target_pid_to_str (lp->ptid));
3239 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3240 gdb_assert (lp->resumed);
3245 /* Make sure we don't report a SIGINT that we have already displayed
3246 for another thread. */
3247 if (lp->ignore_sigint
3248 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3250 if (debug_linux_nat)
3251 fprintf_unfiltered (gdb_stdlog,
3252 "LLW: Delayed SIGINT caught for %s.\n",
3253 target_pid_to_str (lp->ptid));
3255 /* This is a delayed SIGINT. */
3256 lp->ignore_sigint = 0;
3258 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3259 if (debug_linux_nat)
3260 fprintf_unfiltered (gdb_stdlog,
3261 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3263 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3264 target_pid_to_str (lp->ptid));
3265 gdb_assert (lp->resumed);
3267 /* Discard the event. */
3271 /* Don't report signals that GDB isn't interested in, such as
3272 signals that are neither printed nor stopped upon. Stopping all
3273 threads can be a bit time-consuming so if we want decent
3274 performance with heavily multi-threaded programs, especially when
3275 they're using a high frequency timer, we'd better avoid it if we
3277 if (WIFSTOPPED (status))
3279 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3283 /* Only do the below in all-stop, as we currently use SIGSTOP
3284 to implement target_stop (see linux_nat_stop) in
3286 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3288 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3289 forwarded to the entire process group, that is, all LWPs
3290 will receive it - unless they're using CLONE_THREAD to
3291 share signals. Since we only want to report it once, we
3292 mark it as ignored for all LWPs except this one. */
3293 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3294 set_ignore_sigint, NULL);
3295 lp->ignore_sigint = 0;
3298 maybe_clear_ignore_sigint (lp);
3301 /* When using hardware single-step, we need to report every signal.
3302 Otherwise, signals in pass_mask may be short-circuited
3303 except signals that might be caused by a breakpoint. */
3305 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status))
3306 && !linux_wstatus_maybe_breakpoint (status))
3308 linux_resume_one_lwp (lp, lp->step, signo);
3309 if (debug_linux_nat)
3310 fprintf_unfiltered (gdb_stdlog,
3311 "LLW: %s %s, %s (preempt 'handle')\n",
3313 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3314 target_pid_to_str (lp->ptid),
3315 (signo != GDB_SIGNAL_0
3316 ? strsignal (gdb_signal_to_host (signo))
3322 /* An interesting event. */
3324 lp->status = status;
3329 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3330 their exits until all other threads in the group have exited. */
3333 check_zombie_leaders (void)
3335 struct inferior *inf;
3339 struct lwp_info *leader_lp;
3344 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3345 if (leader_lp != NULL
3346 /* Check if there are other threads in the group, as we may
3347 have raced with the inferior simply exiting. */
3348 && num_lwps (inf->pid) > 1
3349 && linux_proc_pid_is_zombie (inf->pid))
3351 if (debug_linux_nat)
3352 fprintf_unfiltered (gdb_stdlog,
3353 "CZL: Thread group leader %d zombie "
3354 "(it exited, or another thread execd).\n",
3357 /* A leader zombie can mean one of two things:
3359 - It exited, and there's an exit status pending
3360 available, or only the leader exited (not the whole
3361 program). In the latter case, we can't waitpid the
3362 leader's exit status until all other threads are gone.
3364 - There are 3 or more threads in the group, and a thread
3365 other than the leader exec'd. On an exec, the Linux
3366 kernel destroys all other threads (except the execing
3367 one) in the thread group, and resets the execing thread's
3368 tid to the tgid. No exit notification is sent for the
3369 execing thread -- from the ptracer's perspective, it
3370 appears as though the execing thread just vanishes.
3371 Until we reap all other threads except the leader and the
3372 execing thread, the leader will be zombie, and the
3373 execing thread will be in `D (disc sleep)'. As soon as
3374 all other threads are reaped, the execing thread changes
3375 it's tid to the tgid, and the previous (zombie) leader
3376 vanishes, giving place to the "new" leader. We could try
3377 distinguishing the exit and exec cases, by waiting once
3378 more, and seeing if something comes out, but it doesn't
3379 sound useful. The previous leader _does_ go away, and
3380 we'll re-add the new one once we see the exec event
3381 (which is just the same as what would happen if the
3382 previous leader did exit voluntarily before some other
3385 if (debug_linux_nat)
3386 fprintf_unfiltered (gdb_stdlog,
3387 "CZL: Thread group leader %d vanished.\n",
3389 exit_lwp (leader_lp);
3395 linux_nat_wait_1 (struct target_ops *ops,
3396 ptid_t ptid, struct target_waitstatus *ourstatus,
3400 enum resume_kind last_resume_kind;
3401 struct lwp_info *lp;
3404 if (debug_linux_nat)
3405 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3407 /* The first time we get here after starting a new inferior, we may
3408 not have added it to the LWP list yet - this is the earliest
3409 moment at which we know its PID. */
3410 if (ptid_is_pid (inferior_ptid))
3412 /* Upgrade the main thread's ptid. */
3413 thread_change_ptid (inferior_ptid,
3414 ptid_build (ptid_get_pid (inferior_ptid),
3415 ptid_get_pid (inferior_ptid), 0));
3417 lp = add_initial_lwp (inferior_ptid);
3421 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3422 block_child_signals (&prev_mask);
3424 /* First check if there is a LWP with a wait status pending. */
3425 lp = iterate_over_lwps (ptid, status_callback, NULL);
3428 if (debug_linux_nat)
3429 fprintf_unfiltered (gdb_stdlog,
3430 "LLW: Using pending wait status %s for %s.\n",
3431 status_to_str (lp->status),
3432 target_pid_to_str (lp->ptid));
3435 if (!target_is_async_p ())
3437 /* Causes SIGINT to be passed on to the attached process. */
3441 /* But if we don't find a pending event, we'll have to wait. Always
3442 pull all events out of the kernel. We'll randomly select an
3443 event LWP out of all that have events, to prevent starvation. */
3449 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3452 - If the thread group leader exits while other threads in the
3453 thread group still exist, waitpid(TGID, ...) hangs. That
3454 waitpid won't return an exit status until the other threads
3455 in the group are reapped.
3457 - When a non-leader thread execs, that thread just vanishes
3458 without reporting an exit (so we'd hang if we waited for it
3459 explicitly in that case). The exec event is reported to
3463 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3464 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3465 lwpid = my_waitpid (-1, &status, WNOHANG);
3467 if (debug_linux_nat)
3468 fprintf_unfiltered (gdb_stdlog,
3469 "LNW: waitpid(-1, ...) returned %d, %s\n",
3470 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3474 if (debug_linux_nat)
3476 fprintf_unfiltered (gdb_stdlog,
3477 "LLW: waitpid %ld received %s\n",
3478 (long) lwpid, status_to_str (status));
3481 linux_nat_filter_event (lwpid, status);
3482 /* Retry until nothing comes out of waitpid. A single
3483 SIGCHLD can indicate more than one child stopped. */
3487 /* Now that we've pulled all events out of the kernel, resume
3488 LWPs that don't have an interesting event to report. */
3489 iterate_over_lwps (minus_one_ptid,
3490 resume_stopped_resumed_lwps, &minus_one_ptid);
3492 /* ... and find an LWP with a status to report to the core, if
3494 lp = iterate_over_lwps (ptid, status_callback, NULL);
3498 /* Check for zombie thread group leaders. Those can't be reaped
3499 until all other threads in the thread group are. */
3500 check_zombie_leaders ();
3502 /* If there are no resumed children left, bail. We'd be stuck
3503 forever in the sigsuspend call below otherwise. */
3504 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3506 if (debug_linux_nat)
3507 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3509 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3511 if (!target_is_async_p ())
3512 clear_sigint_trap ();
3514 restore_child_signals_mask (&prev_mask);
3515 return minus_one_ptid;
3518 /* No interesting event to report to the core. */
3520 if (target_options & TARGET_WNOHANG)
3522 if (debug_linux_nat)
3523 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3525 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3526 restore_child_signals_mask (&prev_mask);
3527 return minus_one_ptid;
3530 /* We shouldn't end up here unless we want to try again. */
3531 gdb_assert (lp == NULL);
3533 /* Block until we get an event reported with SIGCHLD. */
3534 if (debug_linux_nat)
3535 fprintf_unfiltered (gdb_stdlog, "LNW: about to sigsuspend\n");
3536 sigsuspend (&suspend_mask);
3539 if (!target_is_async_p ())
3540 clear_sigint_trap ();
3544 status = lp->status;
3549 /* Now stop all other LWP's ... */
3550 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3552 /* ... and wait until all of them have reported back that
3553 they're no longer running. */
3554 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3557 /* If we're not waiting for a specific LWP, choose an event LWP from
3558 among those that have had events. Giving equal priority to all
3559 LWPs that have had events helps prevent starvation. */
3560 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3561 select_event_lwp (ptid, &lp, &status);
3563 gdb_assert (lp != NULL);
3565 /* Now that we've selected our final event LWP, un-adjust its PC if
3566 it was a software breakpoint, and we can't reliably support the
3567 "stopped by software breakpoint" stop reason. */
3568 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
3569 && !USE_SIGTRAP_SIGINFO)
3571 struct regcache *regcache = get_thread_regcache (lp->ptid);
3572 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3573 int decr_pc = gdbarch_decr_pc_after_break (gdbarch);
3579 pc = regcache_read_pc (regcache);
3580 regcache_write_pc (regcache, pc + decr_pc);
3584 /* We'll need this to determine whether to report a SIGSTOP as
3585 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3587 last_resume_kind = lp->last_resume_kind;
3591 /* In all-stop, from the core's perspective, all LWPs are now
3592 stopped until a new resume action is sent over. */
3593 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3597 resume_clear_callback (lp, NULL);
3600 if (linux_nat_status_is_event (status))
3602 if (debug_linux_nat)
3603 fprintf_unfiltered (gdb_stdlog,
3604 "LLW: trap ptid is %s.\n",
3605 target_pid_to_str (lp->ptid));
3608 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3610 *ourstatus = lp->waitstatus;
3611 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3614 store_waitstatus (ourstatus, status);
3616 if (debug_linux_nat)
3617 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3619 restore_child_signals_mask (&prev_mask);
3621 if (last_resume_kind == resume_stop
3622 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3623 && WSTOPSIG (status) == SIGSTOP)
3625 /* A thread that has been requested to stop by GDB with
3626 target_stop, and it stopped cleanly, so report as SIG0. The
3627 use of SIGSTOP is an implementation detail. */
3628 ourstatus->value.sig = GDB_SIGNAL_0;
3631 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3632 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3635 lp->core = linux_common_core_of_thread (lp->ptid);
3640 /* Resume LWPs that are currently stopped without any pending status
3641 to report, but are resumed from the core's perspective. */
3644 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3646 ptid_t *wait_ptid_p = data;
3650 && !lwp_status_pending_p (lp))
3652 struct regcache *regcache = get_thread_regcache (lp->ptid);
3653 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3657 CORE_ADDR pc = regcache_read_pc (regcache);
3658 int leave_stopped = 0;
3660 /* Don't bother if there's a breakpoint at PC that we'd hit
3661 immediately, and we're not waiting for this LWP. */
3662 if (!ptid_match (lp->ptid, *wait_ptid_p))
3664 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3670 if (debug_linux_nat)
3671 fprintf_unfiltered (gdb_stdlog,
3672 "RSRL: resuming stopped-resumed LWP %s at "
3674 target_pid_to_str (lp->ptid),
3675 paddress (gdbarch, pc),
3678 linux_resume_one_lwp_throw (lp, lp->step, GDB_SIGNAL_0);
3681 CATCH (ex, RETURN_MASK_ERROR)
3683 if (!check_ptrace_stopped_lwp_gone (lp))
3684 throw_exception (ex);
3693 linux_nat_wait (struct target_ops *ops,
3694 ptid_t ptid, struct target_waitstatus *ourstatus,
3699 if (debug_linux_nat)
3701 char *options_string;
3703 options_string = target_options_to_string (target_options);
3704 fprintf_unfiltered (gdb_stdlog,
3705 "linux_nat_wait: [%s], [%s]\n",
3706 target_pid_to_str (ptid),
3708 xfree (options_string);
3711 /* Flush the async file first. */
3712 if (target_is_async_p ())
3713 async_file_flush ();
3715 /* Resume LWPs that are currently stopped without any pending status
3716 to report, but are resumed from the core's perspective. LWPs get
3717 in this state if we find them stopping at a time we're not
3718 interested in reporting the event (target_wait on a
3719 specific_process, for example, see linux_nat_wait_1), and
3720 meanwhile the event became uninteresting. Don't bother resuming
3721 LWPs we're not going to wait for if they'd stop immediately. */
3723 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3725 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3727 /* If we requested any event, and something came out, assume there
3728 may be more. If we requested a specific lwp or process, also
3729 assume there may be more. */
3730 if (target_is_async_p ()
3731 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3732 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3733 || !ptid_equal (ptid, minus_one_ptid)))
3740 kill_callback (struct lwp_info *lp, void *data)
3742 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3745 kill_lwp (ptid_get_lwp (lp->ptid), SIGKILL);
3746 if (debug_linux_nat)
3748 int save_errno = errno;
3750 fprintf_unfiltered (gdb_stdlog,
3751 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3752 target_pid_to_str (lp->ptid),
3753 save_errno ? safe_strerror (save_errno) : "OK");
3756 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3759 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3760 if (debug_linux_nat)
3762 int save_errno = errno;
3764 fprintf_unfiltered (gdb_stdlog,
3765 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3766 target_pid_to_str (lp->ptid),
3767 save_errno ? safe_strerror (save_errno) : "OK");
3774 kill_wait_callback (struct lwp_info *lp, void *data)
3778 /* We must make sure that there are no pending events (delayed
3779 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3780 program doesn't interfere with any following debugging session. */
3782 /* For cloned processes we must check both with __WCLONE and
3783 without, since the exit status of a cloned process isn't reported
3789 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3790 if (pid != (pid_t) -1)
3792 if (debug_linux_nat)
3793 fprintf_unfiltered (gdb_stdlog,
3794 "KWC: wait %s received unknown.\n",
3795 target_pid_to_str (lp->ptid));
3796 /* The Linux kernel sometimes fails to kill a thread
3797 completely after PTRACE_KILL; that goes from the stop
3798 point in do_fork out to the one in
3799 get_signal_to_deliever and waits again. So kill it
3801 kill_callback (lp, NULL);
3804 while (pid == ptid_get_lwp (lp->ptid));
3806 gdb_assert (pid == -1 && errno == ECHILD);
3811 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3812 if (pid != (pid_t) -1)
3814 if (debug_linux_nat)
3815 fprintf_unfiltered (gdb_stdlog,
3816 "KWC: wait %s received unk.\n",
3817 target_pid_to_str (lp->ptid));
3818 /* See the call to kill_callback above. */
3819 kill_callback (lp, NULL);
3822 while (pid == ptid_get_lwp (lp->ptid));
3824 gdb_assert (pid == -1 && errno == ECHILD);
3829 linux_nat_kill (struct target_ops *ops)
3831 struct target_waitstatus last;
3835 /* If we're stopped while forking and we haven't followed yet,
3836 kill the other task. We need to do this first because the
3837 parent will be sleeping if this is a vfork. */
3839 get_last_target_status (&last_ptid, &last);
3841 if (last.kind == TARGET_WAITKIND_FORKED
3842 || last.kind == TARGET_WAITKIND_VFORKED)
3844 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3847 /* Let the arch-specific native code know this process is
3849 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3852 if (forks_exist_p ())
3853 linux_fork_killall ();
3856 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3858 /* Stop all threads before killing them, since ptrace requires
3859 that the thread is stopped to sucessfully PTRACE_KILL. */
3860 iterate_over_lwps (ptid, stop_callback, NULL);
3861 /* ... and wait until all of them have reported back that
3862 they're no longer running. */
3863 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3865 /* Kill all LWP's ... */
3866 iterate_over_lwps (ptid, kill_callback, NULL);
3868 /* ... and wait until we've flushed all events. */
3869 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3872 target_mourn_inferior ();
3876 linux_nat_mourn_inferior (struct target_ops *ops)
3878 int pid = ptid_get_pid (inferior_ptid);
3880 purge_lwp_list (pid);
3882 if (! forks_exist_p ())
3883 /* Normal case, no other forks available. */
3884 linux_ops->to_mourn_inferior (ops);
3886 /* Multi-fork case. The current inferior_ptid has exited, but
3887 there are other viable forks to debug. Delete the exiting
3888 one and context-switch to the first available. */
3889 linux_fork_mourn_inferior ();
3891 /* Let the arch-specific native code know this process is gone. */
3892 linux_nat_forget_process (pid);
3895 /* Convert a native/host siginfo object, into/from the siginfo in the
3896 layout of the inferiors' architecture. */
3899 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3903 if (linux_nat_siginfo_fixup != NULL)
3904 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3906 /* If there was no callback, or the callback didn't do anything,
3907 then just do a straight memcpy. */
3911 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3913 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3917 static enum target_xfer_status
3918 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3919 const char *annex, gdb_byte *readbuf,
3920 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3921 ULONGEST *xfered_len)
3925 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3927 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3928 gdb_assert (readbuf || writebuf);
3930 pid = ptid_get_lwp (inferior_ptid);
3932 pid = ptid_get_pid (inferior_ptid);
3934 if (offset > sizeof (siginfo))
3935 return TARGET_XFER_E_IO;
3938 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3940 return TARGET_XFER_E_IO;
3942 /* When GDB is built as a 64-bit application, ptrace writes into
3943 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3944 inferior with a 64-bit GDB should look the same as debugging it
3945 with a 32-bit GDB, we need to convert it. GDB core always sees
3946 the converted layout, so any read/write will have to be done
3948 siginfo_fixup (&siginfo, inf_siginfo, 0);
3950 if (offset + len > sizeof (siginfo))
3951 len = sizeof (siginfo) - offset;
3953 if (readbuf != NULL)
3954 memcpy (readbuf, inf_siginfo + offset, len);
3957 memcpy (inf_siginfo + offset, writebuf, len);
3959 /* Convert back to ptrace layout before flushing it out. */
3960 siginfo_fixup (&siginfo, inf_siginfo, 1);
3963 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3965 return TARGET_XFER_E_IO;
3969 return TARGET_XFER_OK;
3972 static enum target_xfer_status
3973 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3974 const char *annex, gdb_byte *readbuf,
3975 const gdb_byte *writebuf,
3976 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3978 struct cleanup *old_chain;
3979 enum target_xfer_status xfer;
3981 if (object == TARGET_OBJECT_SIGNAL_INFO)
3982 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3983 offset, len, xfered_len);
3985 /* The target is connected but no live inferior is selected. Pass
3986 this request down to a lower stratum (e.g., the executable
3988 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3989 return TARGET_XFER_EOF;
3991 old_chain = save_inferior_ptid ();
3993 if (ptid_lwp_p (inferior_ptid))
3994 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3996 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3997 offset, len, xfered_len);
3999 do_cleanups (old_chain);
4004 linux_thread_alive (ptid_t ptid)
4008 gdb_assert (ptid_lwp_p (ptid));
4010 /* Send signal 0 instead of anything ptrace, because ptracing a
4011 running thread errors out claiming that the thread doesn't
4013 err = kill_lwp (ptid_get_lwp (ptid), 0);
4015 if (debug_linux_nat)
4016 fprintf_unfiltered (gdb_stdlog,
4017 "LLTA: KILL(SIG0) %s (%s)\n",
4018 target_pid_to_str (ptid),
4019 err ? safe_strerror (tmp_errno) : "OK");
4028 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
4030 return linux_thread_alive (ptid);
4034 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
4036 static char buf[64];
4038 if (ptid_lwp_p (ptid)
4039 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
4040 || num_lwps (ptid_get_pid (ptid)) > 1))
4042 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
4046 return normal_pid_to_str (ptid);
4050 linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
4052 int pid = ptid_get_pid (thr->ptid);
4053 long lwp = ptid_get_lwp (thr->ptid);
4054 #define FORMAT "/proc/%d/task/%ld/comm"
4055 char buf[sizeof (FORMAT) + 30];
4057 char *result = NULL;
4059 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
4060 comm_file = gdb_fopen_cloexec (buf, "r");
4063 /* Not exported by the kernel, so we define it here. */
4065 static char line[COMM_LEN + 1];
4067 if (fgets (line, sizeof (line), comm_file))
4069 char *nl = strchr (line, '\n');
4086 /* Accepts an integer PID; Returns a string representing a file that
4087 can be opened to get the symbols for the child process. */
4090 linux_child_pid_to_exec_file (struct target_ops *self, int pid)
4092 static char buf[PATH_MAX];
4093 char name[PATH_MAX];
4095 xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
4096 memset (buf, 0, PATH_MAX);
4097 if (readlink (name, buf, PATH_MAX - 1) <= 0)
4103 /* Implement the to_xfer_partial interface for memory reads using the /proc
4104 filesystem. Because we can use a single read() call for /proc, this
4105 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4106 but it doesn't support writes. */
4108 static enum target_xfer_status
4109 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4110 const char *annex, gdb_byte *readbuf,
4111 const gdb_byte *writebuf,
4112 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
4118 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4121 /* Don't bother for one word. */
4122 if (len < 3 * sizeof (long))
4123 return TARGET_XFER_EOF;
4125 /* We could keep this file open and cache it - possibly one per
4126 thread. That requires some juggling, but is even faster. */
4127 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
4128 ptid_get_pid (inferior_ptid));
4129 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
4131 return TARGET_XFER_EOF;
4133 /* If pread64 is available, use it. It's faster if the kernel
4134 supports it (only one syscall), and it's 64-bit safe even on
4135 32-bit platforms (for instance, SPARC debugging a SPARC64
4138 if (pread64 (fd, readbuf, len, offset) != len)
4140 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4149 return TARGET_XFER_EOF;
4153 return TARGET_XFER_OK;
4158 /* Enumerate spufs IDs for process PID. */
4160 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
4162 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4164 LONGEST written = 0;
4167 struct dirent *entry;
4169 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4170 dir = opendir (path);
4175 while ((entry = readdir (dir)) != NULL)
4181 fd = atoi (entry->d_name);
4185 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4186 if (stat (path, &st) != 0)
4188 if (!S_ISDIR (st.st_mode))
4191 if (statfs (path, &stfs) != 0)
4193 if (stfs.f_type != SPUFS_MAGIC)
4196 if (pos >= offset && pos + 4 <= offset + len)
4198 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4208 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4209 object type, using the /proc file system. */
4211 static enum target_xfer_status
4212 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4213 const char *annex, gdb_byte *readbuf,
4214 const gdb_byte *writebuf,
4215 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4220 int pid = ptid_get_pid (inferior_ptid);
4225 return TARGET_XFER_E_IO;
4228 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4231 return TARGET_XFER_E_IO;
4233 return TARGET_XFER_EOF;
4236 *xfered_len = (ULONGEST) l;
4237 return TARGET_XFER_OK;
4242 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4243 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4245 return TARGET_XFER_E_IO;
4248 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4251 return TARGET_XFER_EOF;
4255 ret = write (fd, writebuf, (size_t) len);
4257 ret = read (fd, readbuf, (size_t) len);
4262 return TARGET_XFER_E_IO;
4264 return TARGET_XFER_EOF;
4267 *xfered_len = (ULONGEST) ret;
4268 return TARGET_XFER_OK;
4273 /* Parse LINE as a signal set and add its set bits to SIGS. */
4276 add_line_to_sigset (const char *line, sigset_t *sigs)
4278 int len = strlen (line) - 1;
4282 if (line[len] != '\n')
4283 error (_("Could not parse signal set: %s"), line);
4291 if (*p >= '0' && *p <= '9')
4293 else if (*p >= 'a' && *p <= 'f')
4294 digit = *p - 'a' + 10;
4296 error (_("Could not parse signal set: %s"), line);
4301 sigaddset (sigs, signum + 1);
4303 sigaddset (sigs, signum + 2);
4305 sigaddset (sigs, signum + 3);
4307 sigaddset (sigs, signum + 4);
4313 /* Find process PID's pending signals from /proc/pid/status and set
4317 linux_proc_pending_signals (int pid, sigset_t *pending,
4318 sigset_t *blocked, sigset_t *ignored)
4321 char buffer[PATH_MAX], fname[PATH_MAX];
4322 struct cleanup *cleanup;
4324 sigemptyset (pending);
4325 sigemptyset (blocked);
4326 sigemptyset (ignored);
4327 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4328 procfile = gdb_fopen_cloexec (fname, "r");
4329 if (procfile == NULL)
4330 error (_("Could not open %s"), fname);
4331 cleanup = make_cleanup_fclose (procfile);
4333 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4335 /* Normal queued signals are on the SigPnd line in the status
4336 file. However, 2.6 kernels also have a "shared" pending
4337 queue for delivering signals to a thread group, so check for
4340 Unfortunately some Red Hat kernels include the shared pending
4341 queue but not the ShdPnd status field. */
4343 if (startswith (buffer, "SigPnd:\t"))
4344 add_line_to_sigset (buffer + 8, pending);
4345 else if (startswith (buffer, "ShdPnd:\t"))
4346 add_line_to_sigset (buffer + 8, pending);
4347 else if (startswith (buffer, "SigBlk:\t"))
4348 add_line_to_sigset (buffer + 8, blocked);
4349 else if (startswith (buffer, "SigIgn:\t"))
4350 add_line_to_sigset (buffer + 8, ignored);
4353 do_cleanups (cleanup);
4356 static enum target_xfer_status
4357 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4358 const char *annex, gdb_byte *readbuf,
4359 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4360 ULONGEST *xfered_len)
4362 gdb_assert (object == TARGET_OBJECT_OSDATA);
4364 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4365 if (*xfered_len == 0)
4366 return TARGET_XFER_EOF;
4368 return TARGET_XFER_OK;
4371 static enum target_xfer_status
4372 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4373 const char *annex, gdb_byte *readbuf,
4374 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4375 ULONGEST *xfered_len)
4377 enum target_xfer_status xfer;
4379 if (object == TARGET_OBJECT_AUXV)
4380 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4381 offset, len, xfered_len);
4383 if (object == TARGET_OBJECT_OSDATA)
4384 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4385 offset, len, xfered_len);
4387 if (object == TARGET_OBJECT_SPU)
4388 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4389 offset, len, xfered_len);
4391 /* GDB calculates all the addresses in possibly larget width of the address.
4392 Address width needs to be masked before its final use - either by
4393 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4395 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4397 if (object == TARGET_OBJECT_MEMORY)
4399 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4401 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4402 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4405 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4406 offset, len, xfered_len);
4407 if (xfer != TARGET_XFER_EOF)
4410 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4411 offset, len, xfered_len);
4415 cleanup_target_stop (void *arg)
4417 ptid_t *ptid = (ptid_t *) arg;
4419 gdb_assert (arg != NULL);
4422 target_resume (*ptid, 0, GDB_SIGNAL_0);
4425 static VEC(static_tracepoint_marker_p) *
4426 linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
4429 char s[IPA_CMD_BUF_SIZE];
4430 struct cleanup *old_chain;
4431 int pid = ptid_get_pid (inferior_ptid);
4432 VEC(static_tracepoint_marker_p) *markers = NULL;
4433 struct static_tracepoint_marker *marker = NULL;
4435 ptid_t ptid = ptid_build (pid, 0, 0);
4440 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4441 s[sizeof ("qTfSTM")] = 0;
4443 agent_run_command (pid, s, strlen (s) + 1);
4445 old_chain = make_cleanup (free_current_marker, &marker);
4446 make_cleanup (cleanup_target_stop, &ptid);
4451 marker = XCNEW (struct static_tracepoint_marker);
4455 parse_static_tracepoint_marker_definition (p, &p, marker);
4457 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4459 VEC_safe_push (static_tracepoint_marker_p,
4465 release_static_tracepoint_marker (marker);
4466 memset (marker, 0, sizeof (*marker));
4469 while (*p++ == ','); /* comma-separated list */
4471 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4472 s[sizeof ("qTsSTM")] = 0;
4473 agent_run_command (pid, s, strlen (s) + 1);
4477 do_cleanups (old_chain);
4482 /* Create a prototype generic GNU/Linux target. The client can override
4483 it with local methods. */
4486 linux_target_install_ops (struct target_ops *t)
4488 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4489 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4490 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4491 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4492 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4493 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4494 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4495 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4496 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4497 t->to_post_attach = linux_child_post_attach;
4498 t->to_follow_fork = linux_child_follow_fork;
4500 super_xfer_partial = t->to_xfer_partial;
4501 t->to_xfer_partial = linux_xfer_partial;
4503 t->to_static_tracepoint_markers_by_strid
4504 = linux_child_static_tracepoint_markers_by_strid;
4510 struct target_ops *t;
4512 t = inf_ptrace_target ();
4513 linux_target_install_ops (t);
4519 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4521 struct target_ops *t;
4523 t = inf_ptrace_trad_target (register_u_offset);
4524 linux_target_install_ops (t);
4529 /* target_is_async_p implementation. */
4532 linux_nat_is_async_p (struct target_ops *ops)
4534 return linux_is_async_p ();
4537 /* target_can_async_p implementation. */
4540 linux_nat_can_async_p (struct target_ops *ops)
4542 /* NOTE: palves 2008-03-21: We're only async when the user requests
4543 it explicitly with the "set target-async" command.
4544 Someday, linux will always be async. */
4545 return target_async_permitted;
4549 linux_nat_supports_non_stop (struct target_ops *self)
4554 /* True if we want to support multi-process. To be removed when GDB
4555 supports multi-exec. */
4557 int linux_multi_process = 1;
4560 linux_nat_supports_multi_process (struct target_ops *self)
4562 return linux_multi_process;
4566 linux_nat_supports_disable_randomization (struct target_ops *self)
4568 #ifdef HAVE_PERSONALITY
4575 static int async_terminal_is_ours = 1;
4577 /* target_terminal_inferior implementation.
4579 This is a wrapper around child_terminal_inferior to add async support. */
4582 linux_nat_terminal_inferior (struct target_ops *self)
4584 /* Like target_terminal_inferior, use target_can_async_p, not
4585 target_is_async_p, since at this point the target is not async
4586 yet. If it can async, then we know it will become async prior to
4588 if (!target_can_async_p ())
4590 /* Async mode is disabled. */
4591 child_terminal_inferior (self);
4595 child_terminal_inferior (self);
4597 /* Calls to target_terminal_*() are meant to be idempotent. */
4598 if (!async_terminal_is_ours)
4601 delete_file_handler (input_fd);
4602 async_terminal_is_ours = 0;
4606 /* target_terminal_ours implementation.
4608 This is a wrapper around child_terminal_ours to add async support (and
4609 implement the target_terminal_ours vs target_terminal_ours_for_output
4610 distinction). child_terminal_ours is currently no different than
4611 child_terminal_ours_for_output.
4612 We leave target_terminal_ours_for_output alone, leaving it to
4613 child_terminal_ours_for_output. */
4616 linux_nat_terminal_ours (struct target_ops *self)
4618 /* GDB should never give the terminal to the inferior if the
4619 inferior is running in the background (run&, continue&, etc.),
4620 but claiming it sure should. */
4621 child_terminal_ours (self);
4623 if (async_terminal_is_ours)
4626 clear_sigint_trap ();
4627 add_file_handler (input_fd, stdin_event_handler, 0);
4628 async_terminal_is_ours = 1;
4631 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4632 so we notice when any child changes state, and notify the
4633 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4634 above to wait for the arrival of a SIGCHLD. */
4637 sigchld_handler (int signo)
4639 int old_errno = errno;
4641 if (debug_linux_nat)
4642 ui_file_write_async_safe (gdb_stdlog,
4643 "sigchld\n", sizeof ("sigchld\n") - 1);
4645 if (signo == SIGCHLD
4646 && linux_nat_event_pipe[0] != -1)
4647 async_file_mark (); /* Let the event loop know that there are
4648 events to handle. */
4653 /* Callback registered with the target events file descriptor. */
4656 handle_target_event (int error, gdb_client_data client_data)
4658 inferior_event_handler (INF_REG_EVENT, NULL);
4661 /* Create/destroy the target events pipe. Returns previous state. */
4664 linux_async_pipe (int enable)
4666 int previous = linux_is_async_p ();
4668 if (previous != enable)
4672 /* Block child signals while we create/destroy the pipe, as
4673 their handler writes to it. */
4674 block_child_signals (&prev_mask);
4678 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4679 internal_error (__FILE__, __LINE__,
4680 "creating event pipe failed.");
4682 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4683 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4687 close (linux_nat_event_pipe[0]);
4688 close (linux_nat_event_pipe[1]);
4689 linux_nat_event_pipe[0] = -1;
4690 linux_nat_event_pipe[1] = -1;
4693 restore_child_signals_mask (&prev_mask);
4699 /* target_async implementation. */
4702 linux_nat_async (struct target_ops *ops, int enable)
4706 if (!linux_async_pipe (1))
4708 add_file_handler (linux_nat_event_pipe[0],
4709 handle_target_event, NULL);
4710 /* There may be pending events to handle. Tell the event loop
4717 delete_file_handler (linux_nat_event_pipe[0]);
4718 linux_async_pipe (0);
4723 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4727 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4731 if (debug_linux_nat)
4732 fprintf_unfiltered (gdb_stdlog,
4733 "LNSL: running -> suspending %s\n",
4734 target_pid_to_str (lwp->ptid));
4737 if (lwp->last_resume_kind == resume_stop)
4739 if (debug_linux_nat)
4740 fprintf_unfiltered (gdb_stdlog,
4741 "linux-nat: already stopping LWP %ld at "
4743 ptid_get_lwp (lwp->ptid));
4747 stop_callback (lwp, NULL);
4748 lwp->last_resume_kind = resume_stop;
4752 /* Already known to be stopped; do nothing. */
4754 if (debug_linux_nat)
4756 if (find_thread_ptid (lwp->ptid)->stop_requested)
4757 fprintf_unfiltered (gdb_stdlog,
4758 "LNSL: already stopped/stop_requested %s\n",
4759 target_pid_to_str (lwp->ptid));
4761 fprintf_unfiltered (gdb_stdlog,
4762 "LNSL: already stopped/no "
4763 "stop_requested yet %s\n",
4764 target_pid_to_str (lwp->ptid));
4771 linux_nat_stop (struct target_ops *self, ptid_t ptid)
4774 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4776 linux_ops->to_stop (linux_ops, ptid);
4780 linux_nat_close (struct target_ops *self)
4782 /* Unregister from the event loop. */
4783 if (linux_nat_is_async_p (self))
4784 linux_nat_async (self, 0);
4786 if (linux_ops->to_close)
4787 linux_ops->to_close (linux_ops);
4792 /* When requests are passed down from the linux-nat layer to the
4793 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4794 used. The address space pointer is stored in the inferior object,
4795 but the common code that is passed such ptid can't tell whether
4796 lwpid is a "main" process id or not (it assumes so). We reverse
4797 look up the "main" process id from the lwp here. */
4799 static struct address_space *
4800 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4802 struct lwp_info *lwp;
4803 struct inferior *inf;
4806 if (ptid_get_lwp (ptid) == 0)
4808 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4810 lwp = find_lwp_pid (ptid);
4811 pid = ptid_get_pid (lwp->ptid);
4815 /* A (pid,lwpid,0) ptid. */
4816 pid = ptid_get_pid (ptid);
4819 inf = find_inferior_pid (pid);
4820 gdb_assert (inf != NULL);
4824 /* Return the cached value of the processor core for thread PTID. */
4827 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4829 struct lwp_info *info = find_lwp_pid (ptid);
4837 linux_nat_add_target (struct target_ops *t)
4839 /* Save the provided single-threaded target. We save this in a separate
4840 variable because another target we've inherited from (e.g. inf-ptrace)
4841 may have saved a pointer to T; we want to use it for the final
4842 process stratum target. */
4843 linux_ops_saved = *t;
4844 linux_ops = &linux_ops_saved;
4846 /* Override some methods for multithreading. */
4847 t->to_create_inferior = linux_nat_create_inferior;
4848 t->to_attach = linux_nat_attach;
4849 t->to_detach = linux_nat_detach;
4850 t->to_resume = linux_nat_resume;
4851 t->to_wait = linux_nat_wait;
4852 t->to_pass_signals = linux_nat_pass_signals;
4853 t->to_xfer_partial = linux_nat_xfer_partial;
4854 t->to_kill = linux_nat_kill;
4855 t->to_mourn_inferior = linux_nat_mourn_inferior;
4856 t->to_thread_alive = linux_nat_thread_alive;
4857 t->to_pid_to_str = linux_nat_pid_to_str;
4858 t->to_thread_name = linux_nat_thread_name;
4859 t->to_has_thread_control = tc_schedlock;
4860 t->to_thread_address_space = linux_nat_thread_address_space;
4861 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4862 t->to_stopped_data_address = linux_nat_stopped_data_address;
4863 t->to_stopped_by_sw_breakpoint = linux_nat_stopped_by_sw_breakpoint;
4864 t->to_supports_stopped_by_sw_breakpoint = linux_nat_supports_stopped_by_sw_breakpoint;
4865 t->to_stopped_by_hw_breakpoint = linux_nat_stopped_by_hw_breakpoint;
4866 t->to_supports_stopped_by_hw_breakpoint = linux_nat_supports_stopped_by_hw_breakpoint;
4868 t->to_can_async_p = linux_nat_can_async_p;
4869 t->to_is_async_p = linux_nat_is_async_p;
4870 t->to_supports_non_stop = linux_nat_supports_non_stop;
4871 t->to_async = linux_nat_async;
4872 t->to_terminal_inferior = linux_nat_terminal_inferior;
4873 t->to_terminal_ours = linux_nat_terminal_ours;
4875 super_close = t->to_close;
4876 t->to_close = linux_nat_close;
4878 /* Methods for non-stop support. */
4879 t->to_stop = linux_nat_stop;
4881 t->to_supports_multi_process = linux_nat_supports_multi_process;
4883 t->to_supports_disable_randomization
4884 = linux_nat_supports_disable_randomization;
4886 t->to_core_of_thread = linux_nat_core_of_thread;
4888 /* We don't change the stratum; this target will sit at
4889 process_stratum and thread_db will set at thread_stratum. This
4890 is a little strange, since this is a multi-threaded-capable
4891 target, but we want to be on the stack below thread_db, and we
4892 also want to be used for single-threaded processes. */
4897 /* Register a method to call whenever a new thread is attached. */
4899 linux_nat_set_new_thread (struct target_ops *t,
4900 void (*new_thread) (struct lwp_info *))
4902 /* Save the pointer. We only support a single registered instance
4903 of the GNU/Linux native target, so we do not need to map this to
4905 linux_nat_new_thread = new_thread;
4908 /* See declaration in linux-nat.h. */
4911 linux_nat_set_new_fork (struct target_ops *t,
4912 linux_nat_new_fork_ftype *new_fork)
4914 /* Save the pointer. */
4915 linux_nat_new_fork = new_fork;
4918 /* See declaration in linux-nat.h. */
4921 linux_nat_set_forget_process (struct target_ops *t,
4922 linux_nat_forget_process_ftype *fn)
4924 /* Save the pointer. */
4925 linux_nat_forget_process_hook = fn;
4928 /* See declaration in linux-nat.h. */
4931 linux_nat_forget_process (pid_t pid)
4933 if (linux_nat_forget_process_hook != NULL)
4934 linux_nat_forget_process_hook (pid);
4937 /* Register a method that converts a siginfo object between the layout
4938 that ptrace returns, and the layout in the architecture of the
4941 linux_nat_set_siginfo_fixup (struct target_ops *t,
4942 int (*siginfo_fixup) (siginfo_t *,
4946 /* Save the pointer. */
4947 linux_nat_siginfo_fixup = siginfo_fixup;
4950 /* Register a method to call prior to resuming a thread. */
4953 linux_nat_set_prepare_to_resume (struct target_ops *t,
4954 void (*prepare_to_resume) (struct lwp_info *))
4956 /* Save the pointer. */
4957 linux_nat_prepare_to_resume = prepare_to_resume;
4960 /* See linux-nat.h. */
4963 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4967 pid = ptid_get_lwp (ptid);
4969 pid = ptid_get_pid (ptid);
4972 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4975 memset (siginfo, 0, sizeof (*siginfo));
4981 /* See nat/linux-nat.h. */
4984 current_lwp_ptid (void)
4986 gdb_assert (ptid_lwp_p (inferior_ptid));
4987 return inferior_ptid;
4990 /* Provide a prototype to silence -Wmissing-prototypes. */
4991 extern initialize_file_ftype _initialize_linux_nat;
4994 _initialize_linux_nat (void)
4996 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4997 &debug_linux_nat, _("\
4998 Set debugging of GNU/Linux lwp module."), _("\
4999 Show debugging of GNU/Linux lwp module."), _("\
5000 Enables printf debugging output."),
5002 show_debug_linux_nat,
5003 &setdebuglist, &showdebuglist);
5005 /* Save this mask as the default. */
5006 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
5008 /* Install a SIGCHLD handler. */
5009 sigchld_action.sa_handler = sigchld_handler;
5010 sigemptyset (&sigchld_action.sa_mask);
5011 sigchld_action.sa_flags = SA_RESTART;
5013 /* Make it the default. */
5014 sigaction (SIGCHLD, &sigchld_action, NULL);
5016 /* Make sure we don't block SIGCHLD during a sigsuspend. */
5017 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
5018 sigdelset (&suspend_mask, SIGCHLD);
5020 sigemptyset (&blocked_mask);
5022 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
5023 support read-only process state. */
5024 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
5025 | PTRACE_O_TRACEVFORKDONE
5026 | PTRACE_O_TRACEVFORK
5027 | PTRACE_O_TRACEFORK
5028 | PTRACE_O_TRACEEXEC);
5032 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5033 the GNU/Linux Threads library and therefore doesn't really belong
5036 /* Read variable NAME in the target and return its value if found.
5037 Otherwise return zero. It is assumed that the type of the variable
5041 get_signo (const char *name)
5043 struct bound_minimal_symbol ms;
5046 ms = lookup_minimal_symbol (name, NULL, NULL);
5047 if (ms.minsym == NULL)
5050 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
5051 sizeof (signo)) != 0)
5057 /* Return the set of signals used by the threads library in *SET. */
5060 lin_thread_get_thread_signals (sigset_t *set)
5062 struct sigaction action;
5063 int restart, cancel;
5065 sigemptyset (&blocked_mask);
5068 restart = get_signo ("__pthread_sig_restart");
5069 cancel = get_signo ("__pthread_sig_cancel");
5071 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5072 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5073 not provide any way for the debugger to query the signal numbers -
5074 fortunately they don't change! */
5077 restart = __SIGRTMIN;
5080 cancel = __SIGRTMIN + 1;
5082 sigaddset (set, restart);
5083 sigaddset (set, cancel);
5085 /* The GNU/Linux Threads library makes terminating threads send a
5086 special "cancel" signal instead of SIGCHLD. Make sure we catch
5087 those (to prevent them from terminating GDB itself, which is
5088 likely to be their default action) and treat them the same way as
5091 action.sa_handler = sigchld_handler;
5092 sigemptyset (&action.sa_mask);
5093 action.sa_flags = SA_RESTART;
5094 sigaction (cancel, &action, NULL);
5096 /* We block the "cancel" signal throughout this code ... */
5097 sigaddset (&blocked_mask, cancel);
5098 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
5100 /* ... except during a sigsuspend. */
5101 sigdelset (&suspend_mask, cancel);