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;
285 /* Trivial list manipulation functions to keep track of a list of
286 new stopped processes. */
288 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
290 struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
293 new_pid->status = status;
294 new_pid->next = *listp;
299 in_pid_list_p (struct simple_pid_list *list, int pid)
301 struct simple_pid_list *p;
303 for (p = list; p != NULL; p = p->next)
310 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
312 struct simple_pid_list **p;
314 for (p = listp; *p != NULL; p = &(*p)->next)
315 if ((*p)->pid == pid)
317 struct simple_pid_list *next = (*p)->next;
319 *statusp = (*p)->status;
327 /* Initialize ptrace warnings and check for supported ptrace
330 ATTACHED should be nonzero iff we attached to the inferior. */
333 linux_init_ptrace (pid_t pid, int attached)
335 linux_enable_event_reporting (pid, attached);
336 linux_ptrace_init_warnings ();
340 linux_child_post_attach (struct target_ops *self, int pid)
342 linux_init_ptrace (pid, 1);
346 linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
348 linux_init_ptrace (ptid_get_pid (ptid), 0);
351 /* Return the number of known LWPs in the tgid given by PID. */
359 for (lp = lwp_list; lp; lp = lp->next)
360 if (ptid_get_pid (lp->ptid) == pid)
366 /* Call delete_lwp with prototype compatible for make_cleanup. */
369 delete_lwp_cleanup (void *lp_voidp)
371 struct lwp_info *lp = lp_voidp;
373 delete_lwp (lp->ptid);
376 /* Target hook for follow_fork. On entry inferior_ptid must be the
377 ptid of the followed inferior. At return, inferior_ptid will be
381 linux_child_follow_fork (struct target_ops *ops, int follow_child,
386 struct lwp_info *child_lp = NULL;
387 int status = W_STOPCODE (0);
388 struct cleanup *old_chain;
390 ptid_t parent_ptid, child_ptid;
391 int parent_pid, child_pid;
393 has_vforked = (inferior_thread ()->pending_follow.kind
394 == TARGET_WAITKIND_VFORKED);
395 parent_ptid = inferior_ptid;
396 child_ptid = inferior_thread ()->pending_follow.value.related_pid;
397 parent_pid = ptid_get_lwp (parent_ptid);
398 child_pid = ptid_get_lwp (child_ptid);
400 /* We're already attached to the parent, by default. */
401 old_chain = save_inferior_ptid ();
402 inferior_ptid = child_ptid;
403 child_lp = add_lwp (inferior_ptid);
404 child_lp->stopped = 1;
405 child_lp->last_resume_kind = resume_stop;
407 /* Detach new forked process? */
410 make_cleanup (delete_lwp_cleanup, child_lp);
412 if (linux_nat_prepare_to_resume != NULL)
413 linux_nat_prepare_to_resume (child_lp);
415 /* When debugging an inferior in an architecture that supports
416 hardware single stepping on a kernel without commit
417 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
418 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
419 set if the parent process had them set.
420 To work around this, single step the child process
421 once before detaching to clear the flags. */
423 if (!gdbarch_software_single_step_p (target_thread_architecture
426 linux_disable_event_reporting (child_pid);
427 if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
428 perror_with_name (_("Couldn't do single step"));
429 if (my_waitpid (child_pid, &status, 0) < 0)
430 perror_with_name (_("Couldn't wait vfork process"));
433 if (WIFSTOPPED (status))
437 signo = WSTOPSIG (status);
439 && !signal_pass_state (gdb_signal_from_host (signo)))
441 ptrace (PTRACE_DETACH, child_pid, 0, signo);
444 /* Resets value of inferior_ptid to parent ptid. */
445 do_cleanups (old_chain);
449 /* Let the thread_db layer learn about this new process. */
450 check_for_thread_db ();
453 do_cleanups (old_chain);
457 struct lwp_info *parent_lp;
459 parent_lp = find_lwp_pid (parent_ptid);
460 gdb_assert (linux_supports_tracefork () >= 0);
462 if (linux_supports_tracevforkdone ())
465 fprintf_unfiltered (gdb_stdlog,
466 "LCFF: waiting for VFORK_DONE on %d\n",
468 parent_lp->stopped = 1;
470 /* We'll handle the VFORK_DONE event like any other
471 event, in target_wait. */
475 /* We can't insert breakpoints until the child has
476 finished with the shared memory region. We need to
477 wait until that happens. Ideal would be to just
479 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
480 - waitpid (parent_pid, &status, __WALL);
481 However, most architectures can't handle a syscall
482 being traced on the way out if it wasn't traced on
485 We might also think to loop, continuing the child
486 until it exits or gets a SIGTRAP. One problem is
487 that the child might call ptrace with PTRACE_TRACEME.
489 There's no simple and reliable way to figure out when
490 the vforked child will be done with its copy of the
491 shared memory. We could step it out of the syscall,
492 two instructions, let it go, and then single-step the
493 parent once. When we have hardware single-step, this
494 would work; with software single-step it could still
495 be made to work but we'd have to be able to insert
496 single-step breakpoints in the child, and we'd have
497 to insert -just- the single-step breakpoint in the
498 parent. Very awkward.
500 In the end, the best we can do is to make sure it
501 runs for a little while. Hopefully it will be out of
502 range of any breakpoints we reinsert. Usually this
503 is only the single-step breakpoint at vfork's return
507 fprintf_unfiltered (gdb_stdlog,
508 "LCFF: no VFORK_DONE "
509 "support, sleeping a bit\n");
513 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
514 and leave it pending. The next linux_nat_resume call
515 will notice a pending event, and bypasses actually
516 resuming the inferior. */
517 parent_lp->status = 0;
518 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
519 parent_lp->stopped = 1;
521 /* If we're in async mode, need to tell the event loop
522 there's something here to process. */
523 if (target_is_async_p ())
530 struct lwp_info *child_lp;
532 child_lp = add_lwp (inferior_ptid);
533 child_lp->stopped = 1;
534 child_lp->last_resume_kind = resume_stop;
536 /* Let the thread_db layer learn about this new process. */
537 check_for_thread_db ();
545 linux_child_insert_fork_catchpoint (struct target_ops *self, int pid)
547 return !linux_supports_tracefork ();
551 linux_child_remove_fork_catchpoint (struct target_ops *self, int pid)
557 linux_child_insert_vfork_catchpoint (struct target_ops *self, int pid)
559 return !linux_supports_tracefork ();
563 linux_child_remove_vfork_catchpoint (struct target_ops *self, int pid)
569 linux_child_insert_exec_catchpoint (struct target_ops *self, int pid)
571 return !linux_supports_tracefork ();
575 linux_child_remove_exec_catchpoint (struct target_ops *self, int pid)
581 linux_child_set_syscall_catchpoint (struct target_ops *self,
582 int pid, int needed, int any_count,
583 int table_size, int *table)
585 if (!linux_supports_tracesysgood ())
588 /* On GNU/Linux, we ignore the arguments. It means that we only
589 enable the syscall catchpoints, but do not disable them.
591 Also, we do not use the `table' information because we do not
592 filter system calls here. We let GDB do the logic for us. */
596 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
597 are processes sharing the same VM space. A multi-threaded process
598 is basically a group of such processes. However, such a grouping
599 is almost entirely a user-space issue; the kernel doesn't enforce
600 such a grouping at all (this might change in the future). In
601 general, we'll rely on the threads library (i.e. the GNU/Linux
602 Threads library) to provide such a grouping.
604 It is perfectly well possible to write a multi-threaded application
605 without the assistance of a threads library, by using the clone
606 system call directly. This module should be able to give some
607 rudimentary support for debugging such applications if developers
608 specify the CLONE_PTRACE flag in the clone system call, and are
609 using the Linux kernel 2.4 or above.
611 Note that there are some peculiarities in GNU/Linux that affect
614 - In general one should specify the __WCLONE flag to waitpid in
615 order to make it report events for any of the cloned processes
616 (and leave it out for the initial process). However, if a cloned
617 process has exited the exit status is only reported if the
618 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
619 we cannot use it since GDB must work on older systems too.
621 - When a traced, cloned process exits and is waited for by the
622 debugger, the kernel reassigns it to the original parent and
623 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
624 library doesn't notice this, which leads to the "zombie problem":
625 When debugged a multi-threaded process that spawns a lot of
626 threads will run out of processes, even if the threads exit,
627 because the "zombies" stay around. */
629 /* List of known LWPs. */
630 struct lwp_info *lwp_list;
633 /* Original signal mask. */
634 static sigset_t normal_mask;
636 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
637 _initialize_linux_nat. */
638 static sigset_t suspend_mask;
640 /* Signals to block to make that sigsuspend work. */
641 static sigset_t blocked_mask;
643 /* SIGCHLD action. */
644 struct sigaction sigchld_action;
646 /* Block child signals (SIGCHLD and linux threads signals), and store
647 the previous mask in PREV_MASK. */
650 block_child_signals (sigset_t *prev_mask)
652 /* Make sure SIGCHLD is blocked. */
653 if (!sigismember (&blocked_mask, SIGCHLD))
654 sigaddset (&blocked_mask, SIGCHLD);
656 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
659 /* Restore child signals mask, previously returned by
660 block_child_signals. */
663 restore_child_signals_mask (sigset_t *prev_mask)
665 sigprocmask (SIG_SETMASK, prev_mask, NULL);
668 /* Mask of signals to pass directly to the inferior. */
669 static sigset_t pass_mask;
671 /* Update signals to pass to the inferior. */
673 linux_nat_pass_signals (struct target_ops *self,
674 int numsigs, unsigned char *pass_signals)
678 sigemptyset (&pass_mask);
680 for (signo = 1; signo < NSIG; signo++)
682 int target_signo = gdb_signal_from_host (signo);
683 if (target_signo < numsigs && pass_signals[target_signo])
684 sigaddset (&pass_mask, signo);
690 /* Prototypes for local functions. */
691 static int stop_wait_callback (struct lwp_info *lp, void *data);
692 static int linux_thread_alive (ptid_t ptid);
693 static char *linux_child_pid_to_exec_file (struct target_ops *self, int pid);
694 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
698 /* Destroy and free LP. */
701 lwp_free (struct lwp_info *lp)
703 xfree (lp->arch_private);
707 /* Remove all LWPs belong to PID from the lwp list. */
710 purge_lwp_list (int pid)
712 struct lwp_info *lp, *lpprev, *lpnext;
716 for (lp = lwp_list; lp; lp = lpnext)
720 if (ptid_get_pid (lp->ptid) == pid)
725 lpprev->next = lp->next;
734 /* Add the LWP specified by PTID to the list. PTID is the first LWP
735 in the process. Return a pointer to the structure describing the
738 This differs from add_lwp in that we don't let the arch specific
739 bits know about this new thread. Current clients of this callback
740 take the opportunity to install watchpoints in the new thread, and
741 we shouldn't do that for the first thread. If we're spawning a
742 child ("run"), the thread executes the shell wrapper first, and we
743 shouldn't touch it until it execs the program we want to debug.
744 For "attach", it'd be okay to call the callback, but it's not
745 necessary, because watchpoints can't yet have been inserted into
748 static struct lwp_info *
749 add_initial_lwp (ptid_t ptid)
753 gdb_assert (ptid_lwp_p (ptid));
755 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
757 memset (lp, 0, sizeof (struct lwp_info));
759 lp->last_resume_kind = resume_continue;
760 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
771 /* Add the LWP specified by PID to the list. Return a pointer to the
772 structure describing the new LWP. The LWP should already be
775 static struct lwp_info *
776 add_lwp (ptid_t ptid)
780 lp = add_initial_lwp (ptid);
782 /* Let the arch specific bits know about this new thread. Current
783 clients of this callback take the opportunity to install
784 watchpoints in the new thread. We don't do this for the first
785 thread though. See add_initial_lwp. */
786 if (linux_nat_new_thread != NULL)
787 linux_nat_new_thread (lp);
792 /* Remove the LWP specified by PID from the list. */
795 delete_lwp (ptid_t ptid)
797 struct lwp_info *lp, *lpprev;
801 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
802 if (ptid_equal (lp->ptid, ptid))
809 lpprev->next = lp->next;
816 /* Return a pointer to the structure describing the LWP corresponding
817 to PID. If no corresponding LWP could be found, return NULL. */
819 static struct lwp_info *
820 find_lwp_pid (ptid_t ptid)
825 if (ptid_lwp_p (ptid))
826 lwp = ptid_get_lwp (ptid);
828 lwp = ptid_get_pid (ptid);
830 for (lp = lwp_list; lp; lp = lp->next)
831 if (lwp == ptid_get_lwp (lp->ptid))
837 /* Call CALLBACK with its second argument set to DATA for every LWP in
838 the list. If CALLBACK returns 1 for a particular LWP, return a
839 pointer to the structure describing that LWP immediately.
840 Otherwise return NULL. */
843 iterate_over_lwps (ptid_t filter,
844 int (*callback) (struct lwp_info *, void *),
847 struct lwp_info *lp, *lpnext;
849 for (lp = lwp_list; lp; lp = lpnext)
853 if (ptid_match (lp->ptid, filter))
855 if ((*callback) (lp, data))
863 /* Update our internal state when changing from one checkpoint to
864 another indicated by NEW_PTID. We can only switch single-threaded
865 applications, so we only create one new LWP, and the previous list
869 linux_nat_switch_fork (ptid_t new_ptid)
873 purge_lwp_list (ptid_get_pid (inferior_ptid));
875 lp = add_lwp (new_ptid);
878 /* This changes the thread's ptid while preserving the gdb thread
879 num. Also changes the inferior pid, while preserving the
881 thread_change_ptid (inferior_ptid, new_ptid);
883 /* We've just told GDB core that the thread changed target id, but,
884 in fact, it really is a different thread, with different register
886 registers_changed ();
889 /* Handle the exit of a single thread LP. */
892 exit_lwp (struct lwp_info *lp)
894 struct thread_info *th = find_thread_ptid (lp->ptid);
898 if (print_thread_events)
899 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
901 delete_thread (lp->ptid);
904 delete_lwp (lp->ptid);
907 /* Wait for the LWP specified by LP, which we have just attached to.
908 Returns a wait status for that LWP, to cache. */
911 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
914 pid_t new_pid, pid = ptid_get_lwp (ptid);
917 if (linux_proc_pid_is_stopped (pid))
920 fprintf_unfiltered (gdb_stdlog,
921 "LNPAW: Attaching to a stopped process\n");
923 /* The process is definitely stopped. It is in a job control
924 stop, unless the kernel predates the TASK_STOPPED /
925 TASK_TRACED distinction, in which case it might be in a
926 ptrace stop. Make sure it is in a ptrace stop; from there we
927 can kill it, signal it, et cetera.
929 First make sure there is a pending SIGSTOP. Since we are
930 already attached, the process can not transition from stopped
931 to running without a PTRACE_CONT; so we know this signal will
932 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
933 probably already in the queue (unless this kernel is old
934 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
935 is not an RT signal, it can only be queued once. */
936 kill_lwp (pid, SIGSTOP);
938 /* Finally, resume the stopped process. This will deliver the SIGSTOP
939 (or a higher priority signal, just like normal PTRACE_ATTACH). */
940 ptrace (PTRACE_CONT, pid, 0, 0);
943 /* Make sure the initial process is stopped. The user-level threads
944 layer might want to poke around in the inferior, and that won't
945 work if things haven't stabilized yet. */
946 new_pid = my_waitpid (pid, &status, 0);
947 if (new_pid == -1 && errno == ECHILD)
950 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
952 /* Try again with __WCLONE to check cloned processes. */
953 new_pid = my_waitpid (pid, &status, __WCLONE);
957 gdb_assert (pid == new_pid);
959 if (!WIFSTOPPED (status))
961 /* The pid we tried to attach has apparently just exited. */
963 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
964 pid, status_to_str (status));
968 if (WSTOPSIG (status) != SIGSTOP)
972 fprintf_unfiltered (gdb_stdlog,
973 "LNPAW: Received %s after attaching\n",
974 status_to_str (status));
980 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
981 the new LWP could not be attached, or 1 if we're already auto
982 attached to this thread, but haven't processed the
983 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
984 its existance, without considering it an error. */
987 lin_lwp_attach_lwp (ptid_t ptid)
992 gdb_assert (ptid_lwp_p (ptid));
994 lp = find_lwp_pid (ptid);
995 lwpid = ptid_get_lwp (ptid);
997 /* We assume that we're already attached to any LWP that is already
998 in our list of LWPs. If we're not seeing exit events from threads
999 and we've had PID wraparound since we last tried to stop all threads,
1000 this assumption might be wrong; fortunately, this is very unlikely
1004 int status, cloned = 0, signalled = 0;
1006 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1008 if (linux_supports_tracefork ())
1010 /* If we haven't stopped all threads when we get here,
1011 we may have seen a thread listed in thread_db's list,
1012 but not processed the PTRACE_EVENT_CLONE yet. If
1013 that's the case, ignore this new thread, and let
1014 normal event handling discover it later. */
1015 if (in_pid_list_p (stopped_pids, lwpid))
1017 /* We've already seen this thread stop, but we
1018 haven't seen the PTRACE_EVENT_CLONE extended
1020 if (debug_linux_nat)
1021 fprintf_unfiltered (gdb_stdlog,
1022 "LLAL: attach failed, but already seen "
1023 "this thread %s stop\n",
1024 target_pid_to_str (ptid));
1032 if (debug_linux_nat)
1033 fprintf_unfiltered (gdb_stdlog,
1034 "LLAL: attach failed, and haven't seen "
1035 "this thread %s stop yet\n",
1036 target_pid_to_str (ptid));
1038 /* We may or may not be attached to the LWP already.
1039 Try waitpid on it. If that errors, we're not
1040 attached to the LWP yet. Otherwise, we're
1041 already attached. */
1042 gdb_assert (lwpid > 0);
1043 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1044 if (new_pid == -1 && errno == ECHILD)
1045 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1050 /* The child hasn't stopped for its initial
1051 SIGSTOP stop yet. */
1052 if (debug_linux_nat)
1053 fprintf_unfiltered (gdb_stdlog,
1054 "LLAL: child hasn't "
1057 else if (WIFSTOPPED (status))
1059 if (debug_linux_nat)
1060 fprintf_unfiltered (gdb_stdlog,
1061 "LLAL: adding to stopped_pids\n");
1062 add_to_pid_list (&stopped_pids, lwpid, status);
1069 /* If we fail to attach to the thread, issue a warning,
1070 but continue. One way this can happen is if thread
1071 creation is interrupted; as of Linux kernel 2.6.19, a
1072 bug may place threads in the thread list and then fail
1074 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1075 safe_strerror (errno));
1079 if (debug_linux_nat)
1080 fprintf_unfiltered (gdb_stdlog,
1081 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1082 target_pid_to_str (ptid));
1084 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1085 if (!WIFSTOPPED (status))
1088 lp = add_lwp (ptid);
1090 lp->last_resume_kind = resume_stop;
1091 lp->cloned = cloned;
1092 lp->signalled = signalled;
1093 if (WSTOPSIG (status) != SIGSTOP)
1096 lp->status = status;
1099 target_post_attach (ptid_get_lwp (lp->ptid));
1101 if (debug_linux_nat)
1103 fprintf_unfiltered (gdb_stdlog,
1104 "LLAL: waitpid %s received %s\n",
1105 target_pid_to_str (ptid),
1106 status_to_str (status));
1114 linux_nat_create_inferior (struct target_ops *ops,
1115 char *exec_file, char *allargs, char **env,
1118 struct cleanup *restore_personality
1119 = maybe_disable_address_space_randomization (disable_randomization);
1121 /* The fork_child mechanism is synchronous and calls target_wait, so
1122 we have to mask the async mode. */
1124 /* Make sure we report all signals during startup. */
1125 linux_nat_pass_signals (ops, 0, NULL);
1127 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1129 do_cleanups (restore_personality);
1132 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1133 already attached. Returns true if a new LWP is found, false
1137 attach_proc_task_lwp_callback (ptid_t ptid)
1139 struct lwp_info *lp;
1141 /* Ignore LWPs we're already attached to. */
1142 lp = find_lwp_pid (ptid);
1145 int lwpid = ptid_get_lwp (ptid);
1147 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1151 /* Be quiet if we simply raced with the thread exiting.
1152 EPERM is returned if the thread's task still exists, and
1153 is marked as exited or zombie, as well as other
1154 conditions, so in that case, confirm the status in
1155 /proc/PID/status. */
1157 || (err == EPERM && linux_proc_pid_is_gone (lwpid)))
1159 if (debug_linux_nat)
1161 fprintf_unfiltered (gdb_stdlog,
1162 "Cannot attach to lwp %d: "
1163 "thread is gone (%d: %s)\n",
1164 lwpid, err, safe_strerror (err));
1169 warning (_("Cannot attach to lwp %d: %s"),
1171 linux_ptrace_attach_fail_reason_string (ptid,
1177 if (debug_linux_nat)
1178 fprintf_unfiltered (gdb_stdlog,
1179 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1180 target_pid_to_str (ptid));
1182 lp = add_lwp (ptid);
1185 /* The next time we wait for this LWP we'll see a SIGSTOP as
1186 PTRACE_ATTACH brings it to a halt. */
1189 /* We need to wait for a stop before being able to make the
1190 next ptrace call on this LWP. */
1191 lp->must_set_ptrace_flags = 1;
1200 linux_nat_attach (struct target_ops *ops, const char *args, int from_tty)
1202 struct lwp_info *lp;
1206 /* Make sure we report all signals during attach. */
1207 linux_nat_pass_signals (ops, 0, NULL);
1211 linux_ops->to_attach (ops, args, from_tty);
1213 CATCH (ex, RETURN_MASK_ERROR)
1215 pid_t pid = parse_pid_to_attach (args);
1216 struct buffer buffer;
1217 char *message, *buffer_s;
1219 message = xstrdup (ex.message);
1220 make_cleanup (xfree, message);
1222 buffer_init (&buffer);
1223 linux_ptrace_attach_fail_reason (pid, &buffer);
1225 buffer_grow_str0 (&buffer, "");
1226 buffer_s = buffer_finish (&buffer);
1227 make_cleanup (xfree, buffer_s);
1229 if (*buffer_s != '\0')
1230 throw_error (ex.error, "warning: %s\n%s", buffer_s, message);
1232 throw_error (ex.error, "%s", message);
1236 /* The ptrace base target adds the main thread with (pid,0,0)
1237 format. Decorate it with lwp info. */
1238 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1239 ptid_get_pid (inferior_ptid),
1241 thread_change_ptid (inferior_ptid, ptid);
1243 /* Add the initial process as the first LWP to the list. */
1244 lp = add_initial_lwp (ptid);
1246 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1248 if (!WIFSTOPPED (status))
1250 if (WIFEXITED (status))
1252 int exit_code = WEXITSTATUS (status);
1254 target_terminal_ours ();
1255 target_mourn_inferior ();
1257 error (_("Unable to attach: program exited normally."));
1259 error (_("Unable to attach: program exited with code %d."),
1262 else if (WIFSIGNALED (status))
1264 enum gdb_signal signo;
1266 target_terminal_ours ();
1267 target_mourn_inferior ();
1269 signo = gdb_signal_from_host (WTERMSIG (status));
1270 error (_("Unable to attach: program terminated with signal "
1272 gdb_signal_to_name (signo),
1273 gdb_signal_to_string (signo));
1276 internal_error (__FILE__, __LINE__,
1277 _("unexpected status %d for PID %ld"),
1278 status, (long) ptid_get_lwp (ptid));
1283 /* Save the wait status to report later. */
1285 if (debug_linux_nat)
1286 fprintf_unfiltered (gdb_stdlog,
1287 "LNA: waitpid %ld, saving status %s\n",
1288 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1290 lp->status = status;
1292 /* We must attach to every LWP. If /proc is mounted, use that to
1293 find them now. The inferior may be using raw clone instead of
1294 using pthreads. But even if it is using pthreads, thread_db
1295 walks structures in the inferior's address space to find the list
1296 of threads/LWPs, and those structures may well be corrupted.
1297 Note that once thread_db is loaded, we'll still use it to list
1298 threads and associate pthread info with each LWP. */
1299 linux_proc_attach_tgid_threads (ptid_get_pid (lp->ptid),
1300 attach_proc_task_lwp_callback);
1302 if (target_can_async_p ())
1303 target_async (inferior_event_handler, 0);
1306 /* Get pending status of LP. */
1308 get_pending_status (struct lwp_info *lp, int *status)
1310 enum gdb_signal signo = GDB_SIGNAL_0;
1312 /* If we paused threads momentarily, we may have stored pending
1313 events in lp->status or lp->waitstatus (see stop_wait_callback),
1314 and GDB core hasn't seen any signal for those threads.
1315 Otherwise, the last signal reported to the core is found in the
1316 thread object's stop_signal.
1318 There's a corner case that isn't handled here at present. Only
1319 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1320 stop_signal make sense as a real signal to pass to the inferior.
1321 Some catchpoint related events, like
1322 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1323 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1324 those traps are debug API (ptrace in our case) related and
1325 induced; the inferior wouldn't see them if it wasn't being
1326 traced. Hence, we should never pass them to the inferior, even
1327 when set to pass state. Since this corner case isn't handled by
1328 infrun.c when proceeding with a signal, for consistency, neither
1329 do we handle it here (or elsewhere in the file we check for
1330 signal pass state). Normally SIGTRAP isn't set to pass state, so
1331 this is really a corner case. */
1333 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1334 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1335 else if (lp->status)
1336 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1337 else if (non_stop && !is_executing (lp->ptid))
1339 struct thread_info *tp = find_thread_ptid (lp->ptid);
1341 signo = tp->suspend.stop_signal;
1345 struct target_waitstatus last;
1348 get_last_target_status (&last_ptid, &last);
1350 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1352 struct thread_info *tp = find_thread_ptid (lp->ptid);
1354 signo = tp->suspend.stop_signal;
1360 if (signo == GDB_SIGNAL_0)
1362 if (debug_linux_nat)
1363 fprintf_unfiltered (gdb_stdlog,
1364 "GPT: lwp %s has no pending signal\n",
1365 target_pid_to_str (lp->ptid));
1367 else if (!signal_pass_state (signo))
1369 if (debug_linux_nat)
1370 fprintf_unfiltered (gdb_stdlog,
1371 "GPT: lwp %s had signal %s, "
1372 "but it is in no pass state\n",
1373 target_pid_to_str (lp->ptid),
1374 gdb_signal_to_string (signo));
1378 *status = W_STOPCODE (gdb_signal_to_host (signo));
1380 if (debug_linux_nat)
1381 fprintf_unfiltered (gdb_stdlog,
1382 "GPT: lwp %s has pending signal %s\n",
1383 target_pid_to_str (lp->ptid),
1384 gdb_signal_to_string (signo));
1391 detach_callback (struct lwp_info *lp, void *data)
1393 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1395 if (debug_linux_nat && lp->status)
1396 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1397 strsignal (WSTOPSIG (lp->status)),
1398 target_pid_to_str (lp->ptid));
1400 /* If there is a pending SIGSTOP, get rid of it. */
1403 if (debug_linux_nat)
1404 fprintf_unfiltered (gdb_stdlog,
1405 "DC: Sending SIGCONT to %s\n",
1406 target_pid_to_str (lp->ptid));
1408 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1412 /* We don't actually detach from the LWP that has an id equal to the
1413 overall process id just yet. */
1414 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1418 /* Pass on any pending signal for this LWP. */
1419 get_pending_status (lp, &status);
1421 if (linux_nat_prepare_to_resume != NULL)
1422 linux_nat_prepare_to_resume (lp);
1424 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1425 WSTOPSIG (status)) < 0)
1426 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1427 safe_strerror (errno));
1429 if (debug_linux_nat)
1430 fprintf_unfiltered (gdb_stdlog,
1431 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1432 target_pid_to_str (lp->ptid),
1433 strsignal (WSTOPSIG (status)));
1435 delete_lwp (lp->ptid);
1442 linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
1446 struct lwp_info *main_lwp;
1448 pid = ptid_get_pid (inferior_ptid);
1450 /* Don't unregister from the event loop, as there may be other
1451 inferiors running. */
1453 /* Stop all threads before detaching. ptrace requires that the
1454 thread is stopped to sucessfully detach. */
1455 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1456 /* ... and wait until all of them have reported back that
1457 they're no longer running. */
1458 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1460 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1462 /* Only the initial process should be left right now. */
1463 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1465 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1467 /* Pass on any pending signal for the last LWP. */
1468 if ((args == NULL || *args == '\0')
1469 && get_pending_status (main_lwp, &status) != -1
1470 && WIFSTOPPED (status))
1474 /* Put the signal number in ARGS so that inf_ptrace_detach will
1475 pass it along with PTRACE_DETACH. */
1477 xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
1479 if (debug_linux_nat)
1480 fprintf_unfiltered (gdb_stdlog,
1481 "LND: Sending signal %s to %s\n",
1483 target_pid_to_str (main_lwp->ptid));
1486 if (linux_nat_prepare_to_resume != NULL)
1487 linux_nat_prepare_to_resume (main_lwp);
1488 delete_lwp (main_lwp->ptid);
1490 if (forks_exist_p ())
1492 /* Multi-fork case. The current inferior_ptid is being detached
1493 from, but there are other viable forks to debug. Detach from
1494 the current fork, and context-switch to the first
1496 linux_fork_detach (args, from_tty);
1499 linux_ops->to_detach (ops, args, from_tty);
1502 /* Resume execution of the inferior process. If STEP is nonzero,
1503 single-step it. If SIGNAL is nonzero, give it that signal. */
1506 linux_resume_one_lwp_throw (struct lwp_info *lp, int step,
1507 enum gdb_signal signo)
1511 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1512 We only presently need that if the LWP is stepped though (to
1513 handle the case of stepping a breakpoint instruction). */
1516 struct regcache *regcache = get_thread_regcache (lp->ptid);
1518 lp->stop_pc = regcache_read_pc (regcache);
1523 if (linux_nat_prepare_to_resume != NULL)
1524 linux_nat_prepare_to_resume (lp);
1525 linux_ops->to_resume (linux_ops, lp->ptid, step, signo);
1527 /* Successfully resumed. Clear state that no longer makes sense,
1528 and mark the LWP as running. Must not do this before resuming
1529 otherwise if that fails other code will be confused. E.g., we'd
1530 later try to stop the LWP and hang forever waiting for a stop
1531 status. Note that we must not throw after this is cleared,
1532 otherwise handle_zombie_lwp_error would get confused. */
1534 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1535 registers_changed_ptid (lp->ptid);
1538 /* Called when we try to resume a stopped LWP and that errors out. If
1539 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1540 or about to become), discard the error, clear any pending status
1541 the LWP may have, and return true (we'll collect the exit status
1542 soon enough). Otherwise, return false. */
1545 check_ptrace_stopped_lwp_gone (struct lwp_info *lp)
1547 /* If we get an error after resuming the LWP successfully, we'd
1548 confuse !T state for the LWP being gone. */
1549 gdb_assert (lp->stopped);
1551 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1552 because even if ptrace failed with ESRCH, the tracee may be "not
1553 yet fully dead", but already refusing ptrace requests. In that
1554 case the tracee has 'R (Running)' state for a little bit
1555 (observed in Linux 3.18). See also the note on ESRCH in the
1556 ptrace(2) man page. Instead, check whether the LWP has any state
1557 other than ptrace-stopped. */
1559 /* Don't assume anything if /proc/PID/status can't be read. */
1560 if (linux_proc_pid_is_trace_stopped_nowarn (ptid_get_lwp (lp->ptid)) == 0)
1562 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1564 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
1570 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1571 disappears while we try to resume it. */
1574 linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1578 linux_resume_one_lwp_throw (lp, step, signo);
1580 CATCH (ex, RETURN_MASK_ERROR)
1582 if (!check_ptrace_stopped_lwp_gone (lp))
1583 throw_exception (ex);
1591 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1595 struct inferior *inf = find_inferior_ptid (lp->ptid);
1597 if (inf->vfork_child != NULL)
1599 if (debug_linux_nat)
1600 fprintf_unfiltered (gdb_stdlog,
1601 "RC: Not resuming %s (vfork parent)\n",
1602 target_pid_to_str (lp->ptid));
1604 else if (!lwp_status_pending_p (lp))
1606 if (debug_linux_nat)
1607 fprintf_unfiltered (gdb_stdlog,
1608 "RC: Resuming sibling %s, %s, %s\n",
1609 target_pid_to_str (lp->ptid),
1610 (signo != GDB_SIGNAL_0
1611 ? strsignal (gdb_signal_to_host (signo))
1613 step ? "step" : "resume");
1615 linux_resume_one_lwp (lp, step, signo);
1619 if (debug_linux_nat)
1620 fprintf_unfiltered (gdb_stdlog,
1621 "RC: Not resuming sibling %s (has pending)\n",
1622 target_pid_to_str (lp->ptid));
1627 if (debug_linux_nat)
1628 fprintf_unfiltered (gdb_stdlog,
1629 "RC: Not resuming sibling %s (not stopped)\n",
1630 target_pid_to_str (lp->ptid));
1634 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1635 Resume LWP with the last stop signal, if it is in pass state. */
1638 linux_nat_resume_callback (struct lwp_info *lp, void *except)
1640 enum gdb_signal signo = GDB_SIGNAL_0;
1647 struct thread_info *thread;
1649 thread = find_thread_ptid (lp->ptid);
1652 signo = thread->suspend.stop_signal;
1653 thread->suspend.stop_signal = GDB_SIGNAL_0;
1657 resume_lwp (lp, 0, signo);
1662 resume_clear_callback (struct lwp_info *lp, void *data)
1665 lp->last_resume_kind = resume_stop;
1670 resume_set_callback (struct lwp_info *lp, void *data)
1673 lp->last_resume_kind = resume_continue;
1678 linux_nat_resume (struct target_ops *ops,
1679 ptid_t ptid, int step, enum gdb_signal signo)
1681 struct lwp_info *lp;
1684 if (debug_linux_nat)
1685 fprintf_unfiltered (gdb_stdlog,
1686 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1687 step ? "step" : "resume",
1688 target_pid_to_str (ptid),
1689 (signo != GDB_SIGNAL_0
1690 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1691 target_pid_to_str (inferior_ptid));
1693 /* A specific PTID means `step only this process id'. */
1694 resume_many = (ptid_equal (minus_one_ptid, ptid)
1695 || ptid_is_pid (ptid));
1697 /* Mark the lwps we're resuming as resumed. */
1698 iterate_over_lwps (ptid, resume_set_callback, NULL);
1700 /* See if it's the current inferior that should be handled
1703 lp = find_lwp_pid (inferior_ptid);
1705 lp = find_lwp_pid (ptid);
1706 gdb_assert (lp != NULL);
1708 /* Remember if we're stepping. */
1709 lp->last_resume_kind = step ? resume_step : resume_continue;
1711 /* If we have a pending wait status for this thread, there is no
1712 point in resuming the process. But first make sure that
1713 linux_nat_wait won't preemptively handle the event - we
1714 should never take this short-circuit if we are going to
1715 leave LP running, since we have skipped resuming all the
1716 other threads. This bit of code needs to be synchronized
1717 with linux_nat_wait. */
1719 if (lp->status && WIFSTOPPED (lp->status))
1722 && WSTOPSIG (lp->status)
1723 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1725 if (debug_linux_nat)
1726 fprintf_unfiltered (gdb_stdlog,
1727 "LLR: Not short circuiting for ignored "
1728 "status 0x%x\n", lp->status);
1730 /* FIXME: What should we do if we are supposed to continue
1731 this thread with a signal? */
1732 gdb_assert (signo == GDB_SIGNAL_0);
1733 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1738 if (lwp_status_pending_p (lp))
1740 /* FIXME: What should we do if we are supposed to continue
1741 this thread with a signal? */
1742 gdb_assert (signo == GDB_SIGNAL_0);
1744 if (debug_linux_nat)
1745 fprintf_unfiltered (gdb_stdlog,
1746 "LLR: Short circuiting for status 0x%x\n",
1749 if (target_can_async_p ())
1751 target_async (inferior_event_handler, 0);
1752 /* Tell the event loop we have something to process. */
1759 iterate_over_lwps (ptid, linux_nat_resume_callback, lp);
1761 linux_resume_one_lwp (lp, step, signo);
1763 if (debug_linux_nat)
1764 fprintf_unfiltered (gdb_stdlog,
1765 "LLR: %s %s, %s (resume event thread)\n",
1766 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1767 target_pid_to_str (ptid),
1768 (signo != GDB_SIGNAL_0
1769 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1771 if (target_can_async_p ())
1772 target_async (inferior_event_handler, 0);
1775 /* Send a signal to an LWP. */
1778 kill_lwp (int lwpid, int signo)
1780 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1781 fails, then we are not using nptl threads and we should be using kill. */
1783 #ifdef HAVE_TKILL_SYSCALL
1785 static int tkill_failed;
1792 ret = syscall (__NR_tkill, lwpid, signo);
1793 if (errno != ENOSYS)
1800 return kill (lwpid, signo);
1803 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1804 event, check if the core is interested in it: if not, ignore the
1805 event, and keep waiting; otherwise, we need to toggle the LWP's
1806 syscall entry/exit status, since the ptrace event itself doesn't
1807 indicate it, and report the trap to higher layers. */
1810 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1812 struct target_waitstatus *ourstatus = &lp->waitstatus;
1813 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1814 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1818 /* If we're stopping threads, there's a SIGSTOP pending, which
1819 makes it so that the LWP reports an immediate syscall return,
1820 followed by the SIGSTOP. Skip seeing that "return" using
1821 PTRACE_CONT directly, and let stop_wait_callback collect the
1822 SIGSTOP. Later when the thread is resumed, a new syscall
1823 entry event. If we didn't do this (and returned 0), we'd
1824 leave a syscall entry pending, and our caller, by using
1825 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1826 itself. Later, when the user re-resumes this LWP, we'd see
1827 another syscall entry event and we'd mistake it for a return.
1829 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1830 (leaving immediately with LWP->signalled set, without issuing
1831 a PTRACE_CONT), it would still be problematic to leave this
1832 syscall enter pending, as later when the thread is resumed,
1833 it would then see the same syscall exit mentioned above,
1834 followed by the delayed SIGSTOP, while the syscall didn't
1835 actually get to execute. It seems it would be even more
1836 confusing to the user. */
1838 if (debug_linux_nat)
1839 fprintf_unfiltered (gdb_stdlog,
1840 "LHST: ignoring syscall %d "
1841 "for LWP %ld (stopping threads), "
1842 "resuming with PTRACE_CONT for SIGSTOP\n",
1844 ptid_get_lwp (lp->ptid));
1846 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1847 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1852 if (catch_syscall_enabled ())
1854 /* Always update the entry/return state, even if this particular
1855 syscall isn't interesting to the core now. In async mode,
1856 the user could install a new catchpoint for this syscall
1857 between syscall enter/return, and we'll need to know to
1858 report a syscall return if that happens. */
1859 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1860 ? TARGET_WAITKIND_SYSCALL_RETURN
1861 : TARGET_WAITKIND_SYSCALL_ENTRY);
1863 if (catching_syscall_number (syscall_number))
1865 /* Alright, an event to report. */
1866 ourstatus->kind = lp->syscall_state;
1867 ourstatus->value.syscall_number = syscall_number;
1869 if (debug_linux_nat)
1870 fprintf_unfiltered (gdb_stdlog,
1871 "LHST: stopping for %s of syscall %d"
1874 == TARGET_WAITKIND_SYSCALL_ENTRY
1875 ? "entry" : "return",
1877 ptid_get_lwp (lp->ptid));
1881 if (debug_linux_nat)
1882 fprintf_unfiltered (gdb_stdlog,
1883 "LHST: ignoring %s of syscall %d "
1885 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1886 ? "entry" : "return",
1888 ptid_get_lwp (lp->ptid));
1892 /* If we had been syscall tracing, and hence used PT_SYSCALL
1893 before on this LWP, it could happen that the user removes all
1894 syscall catchpoints before we get to process this event.
1895 There are two noteworthy issues here:
1897 - When stopped at a syscall entry event, resuming with
1898 PT_STEP still resumes executing the syscall and reports a
1901 - Only PT_SYSCALL catches syscall enters. If we last
1902 single-stepped this thread, then this event can't be a
1903 syscall enter. If we last single-stepped this thread, this
1904 has to be a syscall exit.
1906 The points above mean that the next resume, be it PT_STEP or
1907 PT_CONTINUE, can not trigger a syscall trace event. */
1908 if (debug_linux_nat)
1909 fprintf_unfiltered (gdb_stdlog,
1910 "LHST: caught syscall event "
1911 "with no syscall catchpoints."
1912 " %d for LWP %ld, ignoring\n",
1914 ptid_get_lwp (lp->ptid));
1915 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1918 /* The core isn't interested in this event. For efficiency, avoid
1919 stopping all threads only to have the core resume them all again.
1920 Since we're not stopping threads, if we're still syscall tracing
1921 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1922 subsequent syscall. Simply resume using the inf-ptrace layer,
1923 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1925 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
1929 /* Handle a GNU/Linux extended wait response. If we see a clone
1930 event, we need to add the new LWP to our list (and not report the
1931 trap to higher layers). This function returns non-zero if the
1932 event should be ignored and we should wait again. If STOPPING is
1933 true, the new LWP remains stopped, otherwise it is continued. */
1936 linux_handle_extended_wait (struct lwp_info *lp, int status,
1939 int pid = ptid_get_lwp (lp->ptid);
1940 struct target_waitstatus *ourstatus = &lp->waitstatus;
1941 int event = linux_ptrace_get_extended_event (status);
1943 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1944 || event == PTRACE_EVENT_CLONE)
1946 unsigned long new_pid;
1949 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
1951 /* If we haven't already seen the new PID stop, wait for it now. */
1952 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
1954 /* The new child has a pending SIGSTOP. We can't affect it until it
1955 hits the SIGSTOP, but we're already attached. */
1956 ret = my_waitpid (new_pid, &status,
1957 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
1959 perror_with_name (_("waiting for new child"));
1960 else if (ret != new_pid)
1961 internal_error (__FILE__, __LINE__,
1962 _("wait returned unexpected PID %d"), ret);
1963 else if (!WIFSTOPPED (status))
1964 internal_error (__FILE__, __LINE__,
1965 _("wait returned unexpected status 0x%x"), status);
1968 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
1970 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
1972 /* The arch-specific native code may need to know about new
1973 forks even if those end up never mapped to an
1975 if (linux_nat_new_fork != NULL)
1976 linux_nat_new_fork (lp, new_pid);
1979 if (event == PTRACE_EVENT_FORK
1980 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
1982 /* Handle checkpointing by linux-fork.c here as a special
1983 case. We don't want the follow-fork-mode or 'catch fork'
1984 to interfere with this. */
1986 /* This won't actually modify the breakpoint list, but will
1987 physically remove the breakpoints from the child. */
1988 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
1990 /* Retain child fork in ptrace (stopped) state. */
1991 if (!find_fork_pid (new_pid))
1994 /* Report as spurious, so that infrun doesn't want to follow
1995 this fork. We're actually doing an infcall in
1997 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
1999 /* Report the stop to the core. */
2003 if (event == PTRACE_EVENT_FORK)
2004 ourstatus->kind = TARGET_WAITKIND_FORKED;
2005 else if (event == PTRACE_EVENT_VFORK)
2006 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2009 struct lwp_info *new_lp;
2011 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2013 if (debug_linux_nat)
2014 fprintf_unfiltered (gdb_stdlog,
2015 "LHEW: Got clone event "
2016 "from LWP %d, new child is LWP %ld\n",
2019 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
2021 new_lp->stopped = 1;
2023 if (WSTOPSIG (status) != SIGSTOP)
2025 /* This can happen if someone starts sending signals to
2026 the new thread before it gets a chance to run, which
2027 have a lower number than SIGSTOP (e.g. SIGUSR1).
2028 This is an unlikely case, and harder to handle for
2029 fork / vfork than for clone, so we do not try - but
2030 we handle it for clone events here. We'll send
2031 the other signal on to the thread below. */
2033 new_lp->signalled = 1;
2037 struct thread_info *tp;
2039 /* When we stop for an event in some other thread, and
2040 pull the thread list just as this thread has cloned,
2041 we'll have seen the new thread in the thread_db list
2042 before handling the CLONE event (glibc's
2043 pthread_create adds the new thread to the thread list
2044 before clone'ing, and has the kernel fill in the
2045 thread's tid on the clone call with
2046 CLONE_PARENT_SETTID). If that happened, and the core
2047 had requested the new thread to stop, we'll have
2048 killed it with SIGSTOP. But since SIGSTOP is not an
2049 RT signal, it can only be queued once. We need to be
2050 careful to not resume the LWP if we wanted it to
2051 stop. In that case, we'll leave the SIGSTOP pending.
2052 It will later be reported as GDB_SIGNAL_0. */
2053 tp = find_thread_ptid (new_lp->ptid);
2054 if (tp != NULL && tp->stop_requested)
2055 new_lp->last_resume_kind = resume_stop;
2060 /* If the thread_db layer is active, let it record the user
2061 level thread id and status, and add the thread to GDB's
2063 if (!thread_db_notice_clone (lp->ptid, new_lp->ptid))
2065 /* The process is not using thread_db. Add the LWP to
2067 target_post_attach (ptid_get_lwp (new_lp->ptid));
2068 add_thread (new_lp->ptid);
2073 set_running (new_lp->ptid, 1);
2074 set_executing (new_lp->ptid, 1);
2075 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2077 new_lp->last_resume_kind = resume_continue;
2082 /* We created NEW_LP so it cannot yet contain STATUS. */
2083 gdb_assert (new_lp->status == 0);
2085 /* Save the wait status to report later. */
2086 if (debug_linux_nat)
2087 fprintf_unfiltered (gdb_stdlog,
2088 "LHEW: waitpid of new LWP %ld, "
2089 "saving status %s\n",
2090 (long) ptid_get_lwp (new_lp->ptid),
2091 status_to_str (status));
2092 new_lp->status = status;
2095 new_lp->resumed = !stopping;
2102 if (event == PTRACE_EVENT_EXEC)
2104 if (debug_linux_nat)
2105 fprintf_unfiltered (gdb_stdlog,
2106 "LHEW: Got exec event from LWP %ld\n",
2107 ptid_get_lwp (lp->ptid));
2109 ourstatus->kind = TARGET_WAITKIND_EXECD;
2110 ourstatus->value.execd_pathname
2111 = xstrdup (linux_child_pid_to_exec_file (NULL, pid));
2113 /* The thread that execed must have been resumed, but, when a
2114 thread execs, it changes its tid to the tgid, and the old
2115 tgid thread might have not been resumed. */
2120 if (event == PTRACE_EVENT_VFORK_DONE)
2122 if (current_inferior ()->waiting_for_vfork_done)
2124 if (debug_linux_nat)
2125 fprintf_unfiltered (gdb_stdlog,
2126 "LHEW: Got expected PTRACE_EVENT_"
2127 "VFORK_DONE from LWP %ld: stopping\n",
2128 ptid_get_lwp (lp->ptid));
2130 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2134 if (debug_linux_nat)
2135 fprintf_unfiltered (gdb_stdlog,
2136 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2137 "from LWP %ld: ignoring\n",
2138 ptid_get_lwp (lp->ptid));
2142 internal_error (__FILE__, __LINE__,
2143 _("unknown ptrace event %d"), event);
2146 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2150 wait_lwp (struct lwp_info *lp)
2154 int thread_dead = 0;
2157 gdb_assert (!lp->stopped);
2158 gdb_assert (lp->status == 0);
2160 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2161 block_child_signals (&prev_mask);
2165 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2166 was right and we should just call sigsuspend. */
2168 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2169 if (pid == -1 && errno == ECHILD)
2170 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2171 if (pid == -1 && errno == ECHILD)
2173 /* The thread has previously exited. We need to delete it
2174 now because, for some vendor 2.4 kernels with NPTL
2175 support backported, there won't be an exit event unless
2176 it is the main thread. 2.6 kernels will report an exit
2177 event for each thread that exits, as expected. */
2179 if (debug_linux_nat)
2180 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2181 target_pid_to_str (lp->ptid));
2186 /* Bugs 10970, 12702.
2187 Thread group leader may have exited in which case we'll lock up in
2188 waitpid if there are other threads, even if they are all zombies too.
2189 Basically, we're not supposed to use waitpid this way.
2190 __WCLONE is not applicable for the leader so we can't use that.
2191 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2192 process; it gets ESRCH both for the zombie and for running processes.
2194 As a workaround, check if we're waiting for the thread group leader and
2195 if it's a zombie, and avoid calling waitpid if it is.
2197 This is racy, what if the tgl becomes a zombie right after we check?
2198 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2199 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2201 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2202 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2205 if (debug_linux_nat)
2206 fprintf_unfiltered (gdb_stdlog,
2207 "WL: Thread group leader %s vanished.\n",
2208 target_pid_to_str (lp->ptid));
2212 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2213 get invoked despite our caller had them intentionally blocked by
2214 block_child_signals. This is sensitive only to the loop of
2215 linux_nat_wait_1 and there if we get called my_waitpid gets called
2216 again before it gets to sigsuspend so we can safely let the handlers
2217 get executed here. */
2219 if (debug_linux_nat)
2220 fprintf_unfiltered (gdb_stdlog, "WL: about to sigsuspend\n");
2221 sigsuspend (&suspend_mask);
2224 restore_child_signals_mask (&prev_mask);
2228 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2230 if (debug_linux_nat)
2232 fprintf_unfiltered (gdb_stdlog,
2233 "WL: waitpid %s received %s\n",
2234 target_pid_to_str (lp->ptid),
2235 status_to_str (status));
2238 /* Check if the thread has exited. */
2239 if (WIFEXITED (status) || WIFSIGNALED (status))
2242 if (debug_linux_nat)
2243 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2244 target_pid_to_str (lp->ptid));
2254 gdb_assert (WIFSTOPPED (status));
2257 if (lp->must_set_ptrace_flags)
2259 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2261 linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
2262 lp->must_set_ptrace_flags = 0;
2265 /* Handle GNU/Linux's syscall SIGTRAPs. */
2266 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2268 /* No longer need the sysgood bit. The ptrace event ends up
2269 recorded in lp->waitstatus if we care for it. We can carry
2270 on handling the event like a regular SIGTRAP from here
2272 status = W_STOPCODE (SIGTRAP);
2273 if (linux_handle_syscall_trap (lp, 1))
2274 return wait_lwp (lp);
2277 /* Handle GNU/Linux's extended waitstatus for trace events. */
2278 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
2279 && linux_is_extended_waitstatus (status))
2281 if (debug_linux_nat)
2282 fprintf_unfiltered (gdb_stdlog,
2283 "WL: Handling extended status 0x%06x\n",
2285 linux_handle_extended_wait (lp, status, 1);
2292 /* Send a SIGSTOP to LP. */
2295 stop_callback (struct lwp_info *lp, void *data)
2297 if (!lp->stopped && !lp->signalled)
2301 if (debug_linux_nat)
2303 fprintf_unfiltered (gdb_stdlog,
2304 "SC: kill %s **<SIGSTOP>**\n",
2305 target_pid_to_str (lp->ptid));
2308 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2309 if (debug_linux_nat)
2311 fprintf_unfiltered (gdb_stdlog,
2312 "SC: lwp kill %d %s\n",
2314 errno ? safe_strerror (errno) : "ERRNO-OK");
2318 gdb_assert (lp->status == 0);
2324 /* Request a stop on LWP. */
2327 linux_stop_lwp (struct lwp_info *lwp)
2329 stop_callback (lwp, NULL);
2332 /* See linux-nat.h */
2335 linux_stop_and_wait_all_lwps (void)
2337 /* Stop all LWP's ... */
2338 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
2340 /* ... and wait until all of them have reported back that
2341 they're no longer running. */
2342 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
2345 /* See linux-nat.h */
2348 linux_unstop_all_lwps (void)
2350 iterate_over_lwps (minus_one_ptid,
2351 resume_stopped_resumed_lwps, &minus_one_ptid);
2354 /* Return non-zero if LWP PID has a pending SIGINT. */
2357 linux_nat_has_pending_sigint (int pid)
2359 sigset_t pending, blocked, ignored;
2361 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2363 if (sigismember (&pending, SIGINT)
2364 && !sigismember (&ignored, SIGINT))
2370 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2373 set_ignore_sigint (struct lwp_info *lp, void *data)
2375 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2376 flag to consume the next one. */
2377 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2378 && WSTOPSIG (lp->status) == SIGINT)
2381 lp->ignore_sigint = 1;
2386 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2387 This function is called after we know the LWP has stopped; if the LWP
2388 stopped before the expected SIGINT was delivered, then it will never have
2389 arrived. Also, if the signal was delivered to a shared queue and consumed
2390 by a different thread, it will never be delivered to this LWP. */
2393 maybe_clear_ignore_sigint (struct lwp_info *lp)
2395 if (!lp->ignore_sigint)
2398 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2400 if (debug_linux_nat)
2401 fprintf_unfiltered (gdb_stdlog,
2402 "MCIS: Clearing bogus flag for %s\n",
2403 target_pid_to_str (lp->ptid));
2404 lp->ignore_sigint = 0;
2408 /* Fetch the possible triggered data watchpoint info and store it in
2411 On some archs, like x86, that use debug registers to set
2412 watchpoints, it's possible that the way to know which watched
2413 address trapped, is to check the register that is used to select
2414 which address to watch. Problem is, between setting the watchpoint
2415 and reading back which data address trapped, the user may change
2416 the set of watchpoints, and, as a consequence, GDB changes the
2417 debug registers in the inferior. To avoid reading back a stale
2418 stopped-data-address when that happens, we cache in LP the fact
2419 that a watchpoint trapped, and the corresponding data address, as
2420 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2421 registers meanwhile, we have the cached data we can rely on. */
2424 check_stopped_by_watchpoint (struct lwp_info *lp)
2426 struct cleanup *old_chain;
2428 if (linux_ops->to_stopped_by_watchpoint == NULL)
2431 old_chain = save_inferior_ptid ();
2432 inferior_ptid = lp->ptid;
2434 if (linux_ops->to_stopped_by_watchpoint (linux_ops))
2436 lp->stop_reason = TARGET_STOPPED_BY_WATCHPOINT;
2438 if (linux_ops->to_stopped_data_address != NULL)
2439 lp->stopped_data_address_p =
2440 linux_ops->to_stopped_data_address (¤t_target,
2441 &lp->stopped_data_address);
2443 lp->stopped_data_address_p = 0;
2446 do_cleanups (old_chain);
2448 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2451 /* Called when the LWP stopped for a trap that could be explained by a
2452 watchpoint or a breakpoint. */
2455 save_sigtrap (struct lwp_info *lp)
2457 gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
2458 gdb_assert (lp->status != 0);
2460 /* Check first if this was a SW/HW breakpoint before checking
2461 watchpoints, because at least s390 can't tell the data address of
2462 hardware watchpoint hits, and the kernel returns
2463 stopped-by-watchpoint as long as there's a watchpoint set. */
2464 if (linux_nat_status_is_event (lp->status))
2465 check_stopped_by_breakpoint (lp);
2467 /* Note that TRAP_HWBKPT can indicate either a hardware breakpoint
2468 or hardware watchpoint. Check which is which if we got
2469 TARGET_STOPPED_BY_HW_BREAKPOINT. */
2470 if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON
2471 || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2472 check_stopped_by_watchpoint (lp);
2475 /* Returns true if the LWP had stopped for a watchpoint. */
2478 linux_nat_stopped_by_watchpoint (struct target_ops *ops)
2480 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2482 gdb_assert (lp != NULL);
2484 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2488 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2490 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2492 gdb_assert (lp != NULL);
2494 *addr_p = lp->stopped_data_address;
2496 return lp->stopped_data_address_p;
2499 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2502 sigtrap_is_event (int status)
2504 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2507 /* Set alternative SIGTRAP-like events recognizer. If
2508 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2512 linux_nat_set_status_is_event (struct target_ops *t,
2513 int (*status_is_event) (int status))
2515 linux_nat_status_is_event = status_is_event;
2518 /* Wait until LP is stopped. */
2521 stop_wait_callback (struct lwp_info *lp, void *data)
2523 struct inferior *inf = find_inferior_ptid (lp->ptid);
2525 /* If this is a vfork parent, bail out, it is not going to report
2526 any SIGSTOP until the vfork is done with. */
2527 if (inf->vfork_child != NULL)
2534 status = wait_lwp (lp);
2538 if (lp->ignore_sigint && WIFSTOPPED (status)
2539 && WSTOPSIG (status) == SIGINT)
2541 lp->ignore_sigint = 0;
2544 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2546 if (debug_linux_nat)
2547 fprintf_unfiltered (gdb_stdlog,
2548 "PTRACE_CONT %s, 0, 0 (%s) "
2549 "(discarding SIGINT)\n",
2550 target_pid_to_str (lp->ptid),
2551 errno ? safe_strerror (errno) : "OK");
2553 return stop_wait_callback (lp, NULL);
2556 maybe_clear_ignore_sigint (lp);
2558 if (WSTOPSIG (status) != SIGSTOP)
2560 /* The thread was stopped with a signal other than SIGSTOP. */
2562 if (debug_linux_nat)
2563 fprintf_unfiltered (gdb_stdlog,
2564 "SWC: Pending event %s in %s\n",
2565 status_to_str ((int) status),
2566 target_pid_to_str (lp->ptid));
2568 /* Save the sigtrap event. */
2569 lp->status = status;
2570 gdb_assert (lp->signalled);
2575 /* We caught the SIGSTOP that we intended to catch, so
2576 there's no SIGSTOP pending. */
2578 if (debug_linux_nat)
2579 fprintf_unfiltered (gdb_stdlog,
2580 "SWC: Delayed SIGSTOP caught for %s.\n",
2581 target_pid_to_str (lp->ptid));
2583 /* Reset SIGNALLED only after the stop_wait_callback call
2584 above as it does gdb_assert on SIGNALLED. */
2592 /* Return non-zero if LP has a wait status pending. Discard the
2593 pending event and resume the LWP if the event that originally
2594 caused the stop became uninteresting. */
2597 status_callback (struct lwp_info *lp, void *data)
2599 /* Only report a pending wait status if we pretend that this has
2600 indeed been resumed. */
2604 if (!lwp_status_pending_p (lp))
2607 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
2608 || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2610 struct regcache *regcache = get_thread_regcache (lp->ptid);
2611 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2615 pc = regcache_read_pc (regcache);
2617 if (pc != lp->stop_pc)
2619 if (debug_linux_nat)
2620 fprintf_unfiltered (gdb_stdlog,
2621 "SC: PC of %s changed. was=%s, now=%s\n",
2622 target_pid_to_str (lp->ptid),
2623 paddress (target_gdbarch (), lp->stop_pc),
2624 paddress (target_gdbarch (), pc));
2628 #if !USE_SIGTRAP_SIGINFO
2629 else if (!breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2631 if (debug_linux_nat)
2632 fprintf_unfiltered (gdb_stdlog,
2633 "SC: previous breakpoint of %s, at %s gone\n",
2634 target_pid_to_str (lp->ptid),
2635 paddress (target_gdbarch (), lp->stop_pc));
2643 if (debug_linux_nat)
2644 fprintf_unfiltered (gdb_stdlog,
2645 "SC: pending event of %s cancelled.\n",
2646 target_pid_to_str (lp->ptid));
2649 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
2657 /* Return non-zero if LP isn't stopped. */
2660 running_callback (struct lwp_info *lp, void *data)
2662 return (!lp->stopped
2663 || (lwp_status_pending_p (lp) && lp->resumed));
2666 /* Count the LWP's that have had events. */
2669 count_events_callback (struct lwp_info *lp, void *data)
2673 gdb_assert (count != NULL);
2675 /* Select only resumed LWPs that have an event pending. */
2676 if (lp->resumed && lwp_status_pending_p (lp))
2682 /* Select the LWP (if any) that is currently being single-stepped. */
2685 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2687 if (lp->last_resume_kind == resume_step
2694 /* Returns true if LP has a status pending. */
2697 lwp_status_pending_p (struct lwp_info *lp)
2699 /* We check for lp->waitstatus in addition to lp->status, because we
2700 can have pending process exits recorded in lp->status and
2701 W_EXITCODE(0,0) happens to be 0. */
2702 return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE;
2705 /* Select the Nth LWP that has had an event. */
2708 select_event_lwp_callback (struct lwp_info *lp, void *data)
2710 int *selector = data;
2712 gdb_assert (selector != NULL);
2714 /* Select only resumed LWPs that have an event pending. */
2715 if (lp->resumed && lwp_status_pending_p (lp))
2716 if ((*selector)-- == 0)
2722 /* Called when the LWP got a signal/trap that could be explained by a
2723 software or hardware breakpoint. */
2726 check_stopped_by_breakpoint (struct lwp_info *lp)
2728 /* Arrange for a breakpoint to be hit again later. We don't keep
2729 the SIGTRAP status and don't forward the SIGTRAP signal to the
2730 LWP. We will handle the current event, eventually we will resume
2731 this LWP, and this breakpoint will trap again.
2733 If we do not do this, then we run the risk that the user will
2734 delete or disable the breakpoint, but the LWP will have already
2737 struct regcache *regcache = get_thread_regcache (lp->ptid);
2738 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2741 #if USE_SIGTRAP_SIGINFO
2745 pc = regcache_read_pc (regcache);
2746 sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch);
2748 #if USE_SIGTRAP_SIGINFO
2749 if (linux_nat_get_siginfo (lp->ptid, &siginfo))
2751 if (siginfo.si_signo == SIGTRAP)
2753 if (siginfo.si_code == GDB_ARCH_TRAP_BRKPT)
2755 if (debug_linux_nat)
2756 fprintf_unfiltered (gdb_stdlog,
2757 "CSBB: Push back software "
2758 "breakpoint for %s\n",
2759 target_pid_to_str (lp->ptid));
2761 /* Back up the PC if necessary. */
2763 regcache_write_pc (regcache, sw_bp_pc);
2765 lp->stop_pc = sw_bp_pc;
2766 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2769 else if (siginfo.si_code == TRAP_HWBKPT)
2771 if (debug_linux_nat)
2772 fprintf_unfiltered (gdb_stdlog,
2773 "CSBB: Push back hardware "
2774 "breakpoint/watchpoint for %s\n",
2775 target_pid_to_str (lp->ptid));
2778 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2784 if ((!lp->step || lp->stop_pc == sw_bp_pc)
2785 && software_breakpoint_inserted_here_p (get_regcache_aspace (regcache),
2788 /* The LWP was either continued, or stepped a software
2789 breakpoint instruction. */
2790 if (debug_linux_nat)
2791 fprintf_unfiltered (gdb_stdlog,
2792 "CB: Push back software breakpoint for %s\n",
2793 target_pid_to_str (lp->ptid));
2795 /* Back up the PC if necessary. */
2797 regcache_write_pc (regcache, sw_bp_pc);
2799 lp->stop_pc = sw_bp_pc;
2800 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2804 if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2806 if (debug_linux_nat)
2807 fprintf_unfiltered (gdb_stdlog,
2808 "CB: Push back hardware breakpoint for %s\n",
2809 target_pid_to_str (lp->ptid));
2812 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2821 /* Returns true if the LWP had stopped for a software breakpoint. */
2824 linux_nat_stopped_by_sw_breakpoint (struct target_ops *ops)
2826 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2828 gdb_assert (lp != NULL);
2830 return lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT;
2833 /* Implement the supports_stopped_by_sw_breakpoint method. */
2836 linux_nat_supports_stopped_by_sw_breakpoint (struct target_ops *ops)
2838 return USE_SIGTRAP_SIGINFO;
2841 /* Returns true if the LWP had stopped for a hardware
2842 breakpoint/watchpoint. */
2845 linux_nat_stopped_by_hw_breakpoint (struct target_ops *ops)
2847 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2849 gdb_assert (lp != NULL);
2851 return lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT;
2854 /* Implement the supports_stopped_by_hw_breakpoint method. */
2857 linux_nat_supports_stopped_by_hw_breakpoint (struct target_ops *ops)
2859 return USE_SIGTRAP_SIGINFO;
2862 /* Select one LWP out of those that have events pending. */
2865 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2868 int random_selector;
2869 struct lwp_info *event_lp = NULL;
2871 /* Record the wait status for the original LWP. */
2872 (*orig_lp)->status = *status;
2874 /* In all-stop, give preference to the LWP that is being
2875 single-stepped. There will be at most one, and it will be the
2876 LWP that the core is most interested in. If we didn't do this,
2877 then we'd have to handle pending step SIGTRAPs somehow in case
2878 the core later continues the previously-stepped thread, as
2879 otherwise we'd report the pending SIGTRAP then, and the core, not
2880 having stepped the thread, wouldn't understand what the trap was
2881 for, and therefore would report it to the user as a random
2885 event_lp = iterate_over_lwps (filter,
2886 select_singlestep_lwp_callback, NULL);
2887 if (event_lp != NULL)
2889 if (debug_linux_nat)
2890 fprintf_unfiltered (gdb_stdlog,
2891 "SEL: Select single-step %s\n",
2892 target_pid_to_str (event_lp->ptid));
2896 if (event_lp == NULL)
2898 /* Pick one at random, out of those which have had events. */
2900 /* First see how many events we have. */
2901 iterate_over_lwps (filter, count_events_callback, &num_events);
2902 gdb_assert (num_events > 0);
2904 /* Now randomly pick a LWP out of those that have had
2906 random_selector = (int)
2907 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2909 if (debug_linux_nat && num_events > 1)
2910 fprintf_unfiltered (gdb_stdlog,
2911 "SEL: Found %d events, selecting #%d\n",
2912 num_events, random_selector);
2914 event_lp = iterate_over_lwps (filter,
2915 select_event_lwp_callback,
2919 if (event_lp != NULL)
2921 /* Switch the event LWP. */
2922 *orig_lp = event_lp;
2923 *status = event_lp->status;
2926 /* Flush the wait status for the event LWP. */
2927 (*orig_lp)->status = 0;
2930 /* Return non-zero if LP has been resumed. */
2933 resumed_callback (struct lwp_info *lp, void *data)
2938 /* Stop an active thread, verify it still exists, then resume it. If
2939 the thread ends up with a pending status, then it is not resumed,
2940 and *DATA (really a pointer to int), is set. */
2943 stop_and_resume_callback (struct lwp_info *lp, void *data)
2947 ptid_t ptid = lp->ptid;
2949 stop_callback (lp, NULL);
2950 stop_wait_callback (lp, NULL);
2952 /* Resume if the lwp still exists, and the core wanted it
2954 lp = find_lwp_pid (ptid);
2957 if (lp->last_resume_kind == resume_stop
2958 && !lwp_status_pending_p (lp))
2960 /* The core wanted the LWP to stop. Even if it stopped
2961 cleanly (with SIGSTOP), leave the event pending. */
2962 if (debug_linux_nat)
2963 fprintf_unfiltered (gdb_stdlog,
2964 "SARC: core wanted LWP %ld stopped "
2965 "(leaving SIGSTOP pending)\n",
2966 ptid_get_lwp (lp->ptid));
2967 lp->status = W_STOPCODE (SIGSTOP);
2970 if (!lwp_status_pending_p (lp))
2972 if (debug_linux_nat)
2973 fprintf_unfiltered (gdb_stdlog,
2974 "SARC: re-resuming LWP %ld\n",
2975 ptid_get_lwp (lp->ptid));
2976 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2980 if (debug_linux_nat)
2981 fprintf_unfiltered (gdb_stdlog,
2982 "SARC: not re-resuming LWP %ld "
2984 ptid_get_lwp (lp->ptid));
2991 /* Check if we should go on and pass this event to common code.
2992 Return the affected lwp if we are, or NULL otherwise. */
2994 static struct lwp_info *
2995 linux_nat_filter_event (int lwpid, int status)
2997 struct lwp_info *lp;
2998 int event = linux_ptrace_get_extended_event (status);
3000 lp = find_lwp_pid (pid_to_ptid (lwpid));
3002 /* Check for stop events reported by a process we didn't already
3003 know about - anything not already in our LWP list.
3005 If we're expecting to receive stopped processes after
3006 fork, vfork, and clone events, then we'll just add the
3007 new one to our list and go back to waiting for the event
3008 to be reported - the stopped process might be returned
3009 from waitpid before or after the event is.
3011 But note the case of a non-leader thread exec'ing after the
3012 leader having exited, and gone from our lists. The non-leader
3013 thread changes its tid to the tgid. */
3015 if (WIFSTOPPED (status) && lp == NULL
3016 && (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
3018 /* A multi-thread exec after we had seen the leader exiting. */
3019 if (debug_linux_nat)
3020 fprintf_unfiltered (gdb_stdlog,
3021 "LLW: Re-adding thread group leader LWP %d.\n",
3024 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
3027 add_thread (lp->ptid);
3030 if (WIFSTOPPED (status) && !lp)
3032 if (debug_linux_nat)
3033 fprintf_unfiltered (gdb_stdlog,
3034 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
3035 (long) lwpid, status_to_str (status));
3036 add_to_pid_list (&stopped_pids, lwpid, status);
3040 /* Make sure we don't report an event for the exit of an LWP not in
3041 our list, i.e. not part of the current process. This can happen
3042 if we detach from a program we originally forked and then it
3044 if (!WIFSTOPPED (status) && !lp)
3047 /* This LWP is stopped now. (And if dead, this prevents it from
3048 ever being continued.) */
3051 if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
3053 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
3055 linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
3056 lp->must_set_ptrace_flags = 0;
3059 /* Handle GNU/Linux's syscall SIGTRAPs. */
3060 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
3062 /* No longer need the sysgood bit. The ptrace event ends up
3063 recorded in lp->waitstatus if we care for it. We can carry
3064 on handling the event like a regular SIGTRAP from here
3066 status = W_STOPCODE (SIGTRAP);
3067 if (linux_handle_syscall_trap (lp, 0))
3071 /* Handle GNU/Linux's extended waitstatus for trace events. */
3072 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
3073 && linux_is_extended_waitstatus (status))
3075 if (debug_linux_nat)
3076 fprintf_unfiltered (gdb_stdlog,
3077 "LLW: Handling extended status 0x%06x\n",
3079 if (linux_handle_extended_wait (lp, status, 0))
3083 /* Check if the thread has exited. */
3084 if (WIFEXITED (status) || WIFSIGNALED (status))
3086 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3088 /* If this is the main thread, we must stop all threads and
3089 verify if they are still alive. This is because in the
3090 nptl thread model on Linux 2.4, there is no signal issued
3091 for exiting LWPs other than the main thread. We only get
3092 the main thread exit signal once all child threads have
3093 already exited. If we stop all the threads and use the
3094 stop_wait_callback to check if they have exited we can
3095 determine whether this signal should be ignored or
3096 whether it means the end of the debugged application,
3097 regardless of which threading model is being used. */
3098 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
3100 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3101 stop_and_resume_callback, NULL);
3104 if (debug_linux_nat)
3105 fprintf_unfiltered (gdb_stdlog,
3106 "LLW: %s exited.\n",
3107 target_pid_to_str (lp->ptid));
3109 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3111 /* If there is at least one more LWP, then the exit signal
3112 was not the end of the debugged application and should be
3119 gdb_assert (lp->resumed);
3121 if (debug_linux_nat)
3122 fprintf_unfiltered (gdb_stdlog,
3123 "Process %ld exited\n",
3124 ptid_get_lwp (lp->ptid));
3126 /* This was the last lwp in the process. Since events are
3127 serialized to GDB core, we may not be able report this one
3128 right now, but GDB core and the other target layers will want
3129 to be notified about the exit code/signal, leave the status
3130 pending for the next time we're able to report it. */
3132 /* Dead LWP's aren't expected to reported a pending sigstop. */
3135 /* Store the pending event in the waitstatus, because
3136 W_EXITCODE(0,0) == 0. */
3137 store_waitstatus (&lp->waitstatus, status);
3141 /* Check if the current LWP has previously exited. In the nptl
3142 thread model, LWPs other than the main thread do not issue
3143 signals when they exit so we must check whenever the thread has
3144 stopped. A similar check is made in stop_wait_callback(). */
3145 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3147 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3149 if (debug_linux_nat)
3150 fprintf_unfiltered (gdb_stdlog,
3151 "LLW: %s exited.\n",
3152 target_pid_to_str (lp->ptid));
3156 /* Make sure there is at least one thread running. */
3157 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3159 /* Discard the event. */
3163 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3164 an attempt to stop an LWP. */
3166 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3168 if (debug_linux_nat)
3169 fprintf_unfiltered (gdb_stdlog,
3170 "LLW: Delayed SIGSTOP caught for %s.\n",
3171 target_pid_to_str (lp->ptid));
3175 if (lp->last_resume_kind != resume_stop)
3177 /* This is a delayed SIGSTOP. */
3179 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3180 if (debug_linux_nat)
3181 fprintf_unfiltered (gdb_stdlog,
3182 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3184 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3185 target_pid_to_str (lp->ptid));
3187 gdb_assert (lp->resumed);
3189 /* Discard the event. */
3194 /* Make sure we don't report a SIGINT that we have already displayed
3195 for another thread. */
3196 if (lp->ignore_sigint
3197 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3199 if (debug_linux_nat)
3200 fprintf_unfiltered (gdb_stdlog,
3201 "LLW: Delayed SIGINT caught for %s.\n",
3202 target_pid_to_str (lp->ptid));
3204 /* This is a delayed SIGINT. */
3205 lp->ignore_sigint = 0;
3207 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
3208 if (debug_linux_nat)
3209 fprintf_unfiltered (gdb_stdlog,
3210 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3212 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3213 target_pid_to_str (lp->ptid));
3214 gdb_assert (lp->resumed);
3216 /* Discard the event. */
3220 /* Don't report signals that GDB isn't interested in, such as
3221 signals that are neither printed nor stopped upon. Stopping all
3222 threads can be a bit time-consuming so if we want decent
3223 performance with heavily multi-threaded programs, especially when
3224 they're using a high frequency timer, we'd better avoid it if we
3226 if (WIFSTOPPED (status))
3228 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3232 /* Only do the below in all-stop, as we currently use SIGSTOP
3233 to implement target_stop (see linux_nat_stop) in
3235 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3237 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3238 forwarded to the entire process group, that is, all LWPs
3239 will receive it - unless they're using CLONE_THREAD to
3240 share signals. Since we only want to report it once, we
3241 mark it as ignored for all LWPs except this one. */
3242 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3243 set_ignore_sigint, NULL);
3244 lp->ignore_sigint = 0;
3247 maybe_clear_ignore_sigint (lp);
3250 /* When using hardware single-step, we need to report every signal.
3251 Otherwise, signals in pass_mask may be short-circuited
3252 except signals that might be caused by a breakpoint. */
3254 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status))
3255 && !linux_wstatus_maybe_breakpoint (status))
3257 linux_resume_one_lwp (lp, lp->step, signo);
3258 if (debug_linux_nat)
3259 fprintf_unfiltered (gdb_stdlog,
3260 "LLW: %s %s, %s (preempt 'handle')\n",
3262 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3263 target_pid_to_str (lp->ptid),
3264 (signo != GDB_SIGNAL_0
3265 ? strsignal (gdb_signal_to_host (signo))
3271 /* An interesting event. */
3273 lp->status = status;
3278 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3279 their exits until all other threads in the group have exited. */
3282 check_zombie_leaders (void)
3284 struct inferior *inf;
3288 struct lwp_info *leader_lp;
3293 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3294 if (leader_lp != NULL
3295 /* Check if there are other threads in the group, as we may
3296 have raced with the inferior simply exiting. */
3297 && num_lwps (inf->pid) > 1
3298 && linux_proc_pid_is_zombie (inf->pid))
3300 if (debug_linux_nat)
3301 fprintf_unfiltered (gdb_stdlog,
3302 "CZL: Thread group leader %d zombie "
3303 "(it exited, or another thread execd).\n",
3306 /* A leader zombie can mean one of two things:
3308 - It exited, and there's an exit status pending
3309 available, or only the leader exited (not the whole
3310 program). In the latter case, we can't waitpid the
3311 leader's exit status until all other threads are gone.
3313 - There are 3 or more threads in the group, and a thread
3314 other than the leader exec'd. On an exec, the Linux
3315 kernel destroys all other threads (except the execing
3316 one) in the thread group, and resets the execing thread's
3317 tid to the tgid. No exit notification is sent for the
3318 execing thread -- from the ptracer's perspective, it
3319 appears as though the execing thread just vanishes.
3320 Until we reap all other threads except the leader and the
3321 execing thread, the leader will be zombie, and the
3322 execing thread will be in `D (disc sleep)'. As soon as
3323 all other threads are reaped, the execing thread changes
3324 it's tid to the tgid, and the previous (zombie) leader
3325 vanishes, giving place to the "new" leader. We could try
3326 distinguishing the exit and exec cases, by waiting once
3327 more, and seeing if something comes out, but it doesn't
3328 sound useful. The previous leader _does_ go away, and
3329 we'll re-add the new one once we see the exec event
3330 (which is just the same as what would happen if the
3331 previous leader did exit voluntarily before some other
3334 if (debug_linux_nat)
3335 fprintf_unfiltered (gdb_stdlog,
3336 "CZL: Thread group leader %d vanished.\n",
3338 exit_lwp (leader_lp);
3344 linux_nat_wait_1 (struct target_ops *ops,
3345 ptid_t ptid, struct target_waitstatus *ourstatus,
3349 enum resume_kind last_resume_kind;
3350 struct lwp_info *lp;
3353 if (debug_linux_nat)
3354 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3356 /* The first time we get here after starting a new inferior, we may
3357 not have added it to the LWP list yet - this is the earliest
3358 moment at which we know its PID. */
3359 if (ptid_is_pid (inferior_ptid))
3361 /* Upgrade the main thread's ptid. */
3362 thread_change_ptid (inferior_ptid,
3363 ptid_build (ptid_get_pid (inferior_ptid),
3364 ptid_get_pid (inferior_ptid), 0));
3366 lp = add_initial_lwp (inferior_ptid);
3370 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3371 block_child_signals (&prev_mask);
3373 /* First check if there is a LWP with a wait status pending. */
3374 lp = iterate_over_lwps (ptid, status_callback, NULL);
3377 if (debug_linux_nat)
3378 fprintf_unfiltered (gdb_stdlog,
3379 "LLW: Using pending wait status %s for %s.\n",
3380 status_to_str (lp->status),
3381 target_pid_to_str (lp->ptid));
3384 if (!target_is_async_p ())
3386 /* Causes SIGINT to be passed on to the attached process. */
3390 /* But if we don't find a pending event, we'll have to wait. Always
3391 pull all events out of the kernel. We'll randomly select an
3392 event LWP out of all that have events, to prevent starvation. */
3398 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3401 - If the thread group leader exits while other threads in the
3402 thread group still exist, waitpid(TGID, ...) hangs. That
3403 waitpid won't return an exit status until the other threads
3404 in the group are reapped.
3406 - When a non-leader thread execs, that thread just vanishes
3407 without reporting an exit (so we'd hang if we waited for it
3408 explicitly in that case). The exec event is reported to
3412 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3413 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3414 lwpid = my_waitpid (-1, &status, WNOHANG);
3416 if (debug_linux_nat)
3417 fprintf_unfiltered (gdb_stdlog,
3418 "LNW: waitpid(-1, ...) returned %d, %s\n",
3419 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3423 if (debug_linux_nat)
3425 fprintf_unfiltered (gdb_stdlog,
3426 "LLW: waitpid %ld received %s\n",
3427 (long) lwpid, status_to_str (status));
3430 linux_nat_filter_event (lwpid, status);
3431 /* Retry until nothing comes out of waitpid. A single
3432 SIGCHLD can indicate more than one child stopped. */
3436 /* Now that we've pulled all events out of the kernel, resume
3437 LWPs that don't have an interesting event to report. */
3438 iterate_over_lwps (minus_one_ptid,
3439 resume_stopped_resumed_lwps, &minus_one_ptid);
3441 /* ... and find an LWP with a status to report to the core, if
3443 lp = iterate_over_lwps (ptid, status_callback, NULL);
3447 /* Check for zombie thread group leaders. Those can't be reaped
3448 until all other threads in the thread group are. */
3449 check_zombie_leaders ();
3451 /* If there are no resumed children left, bail. We'd be stuck
3452 forever in the sigsuspend call below otherwise. */
3453 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3455 if (debug_linux_nat)
3456 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3458 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3460 if (!target_is_async_p ())
3461 clear_sigint_trap ();
3463 restore_child_signals_mask (&prev_mask);
3464 return minus_one_ptid;
3467 /* No interesting event to report to the core. */
3469 if (target_options & TARGET_WNOHANG)
3471 if (debug_linux_nat)
3472 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3474 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3475 restore_child_signals_mask (&prev_mask);
3476 return minus_one_ptid;
3479 /* We shouldn't end up here unless we want to try again. */
3480 gdb_assert (lp == NULL);
3482 /* Block until we get an event reported with SIGCHLD. */
3483 if (debug_linux_nat)
3484 fprintf_unfiltered (gdb_stdlog, "LNW: about to sigsuspend\n");
3485 sigsuspend (&suspend_mask);
3488 if (!target_is_async_p ())
3489 clear_sigint_trap ();
3493 status = lp->status;
3498 /* Now stop all other LWP's ... */
3499 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3501 /* ... and wait until all of them have reported back that
3502 they're no longer running. */
3503 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3506 /* If we're not waiting for a specific LWP, choose an event LWP from
3507 among those that have had events. Giving equal priority to all
3508 LWPs that have had events helps prevent starvation. */
3509 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3510 select_event_lwp (ptid, &lp, &status);
3512 gdb_assert (lp != NULL);
3514 /* Now that we've selected our final event LWP, un-adjust its PC if
3515 it was a software breakpoint, and we can't reliably support the
3516 "stopped by software breakpoint" stop reason. */
3517 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
3518 && !USE_SIGTRAP_SIGINFO)
3520 struct regcache *regcache = get_thread_regcache (lp->ptid);
3521 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3522 int decr_pc = gdbarch_decr_pc_after_break (gdbarch);
3528 pc = regcache_read_pc (regcache);
3529 regcache_write_pc (regcache, pc + decr_pc);
3533 /* We'll need this to determine whether to report a SIGSTOP as
3534 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3536 last_resume_kind = lp->last_resume_kind;
3540 /* In all-stop, from the core's perspective, all LWPs are now
3541 stopped until a new resume action is sent over. */
3542 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3546 resume_clear_callback (lp, NULL);
3549 if (linux_nat_status_is_event (status))
3551 if (debug_linux_nat)
3552 fprintf_unfiltered (gdb_stdlog,
3553 "LLW: trap ptid is %s.\n",
3554 target_pid_to_str (lp->ptid));
3557 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3559 *ourstatus = lp->waitstatus;
3560 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3563 store_waitstatus (ourstatus, status);
3565 if (debug_linux_nat)
3566 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3568 restore_child_signals_mask (&prev_mask);
3570 if (last_resume_kind == resume_stop
3571 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3572 && WSTOPSIG (status) == SIGSTOP)
3574 /* A thread that has been requested to stop by GDB with
3575 target_stop, and it stopped cleanly, so report as SIG0. The
3576 use of SIGSTOP is an implementation detail. */
3577 ourstatus->value.sig = GDB_SIGNAL_0;
3580 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3581 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3584 lp->core = linux_common_core_of_thread (lp->ptid);
3589 /* Resume LWPs that are currently stopped without any pending status
3590 to report, but are resumed from the core's perspective. */
3593 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3595 ptid_t *wait_ptid_p = data;
3599 && !lwp_status_pending_p (lp))
3601 struct regcache *regcache = get_thread_regcache (lp->ptid);
3602 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3606 CORE_ADDR pc = regcache_read_pc (regcache);
3607 int leave_stopped = 0;
3609 /* Don't bother if there's a breakpoint at PC that we'd hit
3610 immediately, and we're not waiting for this LWP. */
3611 if (!ptid_match (lp->ptid, *wait_ptid_p))
3613 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3619 if (debug_linux_nat)
3620 fprintf_unfiltered (gdb_stdlog,
3621 "RSRL: resuming stopped-resumed LWP %s at "
3623 target_pid_to_str (lp->ptid),
3624 paddress (gdbarch, pc),
3627 linux_resume_one_lwp_throw (lp, lp->step, GDB_SIGNAL_0);
3630 CATCH (ex, RETURN_MASK_ERROR)
3632 if (!check_ptrace_stopped_lwp_gone (lp))
3633 throw_exception (ex);
3642 linux_nat_wait (struct target_ops *ops,
3643 ptid_t ptid, struct target_waitstatus *ourstatus,
3648 if (debug_linux_nat)
3650 char *options_string;
3652 options_string = target_options_to_string (target_options);
3653 fprintf_unfiltered (gdb_stdlog,
3654 "linux_nat_wait: [%s], [%s]\n",
3655 target_pid_to_str (ptid),
3657 xfree (options_string);
3660 /* Flush the async file first. */
3661 if (target_is_async_p ())
3662 async_file_flush ();
3664 /* Resume LWPs that are currently stopped without any pending status
3665 to report, but are resumed from the core's perspective. LWPs get
3666 in this state if we find them stopping at a time we're not
3667 interested in reporting the event (target_wait on a
3668 specific_process, for example, see linux_nat_wait_1), and
3669 meanwhile the event became uninteresting. Don't bother resuming
3670 LWPs we're not going to wait for if they'd stop immediately. */
3672 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3674 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3676 /* If we requested any event, and something came out, assume there
3677 may be more. If we requested a specific lwp or process, also
3678 assume there may be more. */
3679 if (target_is_async_p ()
3680 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3681 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3682 || !ptid_equal (ptid, minus_one_ptid)))
3689 kill_callback (struct lwp_info *lp, void *data)
3691 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3694 kill_lwp (ptid_get_lwp (lp->ptid), SIGKILL);
3695 if (debug_linux_nat)
3697 int save_errno = errno;
3699 fprintf_unfiltered (gdb_stdlog,
3700 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3701 target_pid_to_str (lp->ptid),
3702 save_errno ? safe_strerror (save_errno) : "OK");
3705 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3708 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3709 if (debug_linux_nat)
3711 int save_errno = errno;
3713 fprintf_unfiltered (gdb_stdlog,
3714 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3715 target_pid_to_str (lp->ptid),
3716 save_errno ? safe_strerror (save_errno) : "OK");
3723 kill_wait_callback (struct lwp_info *lp, void *data)
3727 /* We must make sure that there are no pending events (delayed
3728 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3729 program doesn't interfere with any following debugging session. */
3731 /* For cloned processes we must check both with __WCLONE and
3732 without, since the exit status of a cloned process isn't reported
3738 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3739 if (pid != (pid_t) -1)
3741 if (debug_linux_nat)
3742 fprintf_unfiltered (gdb_stdlog,
3743 "KWC: wait %s received unknown.\n",
3744 target_pid_to_str (lp->ptid));
3745 /* The Linux kernel sometimes fails to kill a thread
3746 completely after PTRACE_KILL; that goes from the stop
3747 point in do_fork out to the one in
3748 get_signal_to_deliever and waits again. So kill it
3750 kill_callback (lp, NULL);
3753 while (pid == ptid_get_lwp (lp->ptid));
3755 gdb_assert (pid == -1 && errno == ECHILD);
3760 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3761 if (pid != (pid_t) -1)
3763 if (debug_linux_nat)
3764 fprintf_unfiltered (gdb_stdlog,
3765 "KWC: wait %s received unk.\n",
3766 target_pid_to_str (lp->ptid));
3767 /* See the call to kill_callback above. */
3768 kill_callback (lp, NULL);
3771 while (pid == ptid_get_lwp (lp->ptid));
3773 gdb_assert (pid == -1 && errno == ECHILD);
3778 linux_nat_kill (struct target_ops *ops)
3780 struct target_waitstatus last;
3784 /* If we're stopped while forking and we haven't followed yet,
3785 kill the other task. We need to do this first because the
3786 parent will be sleeping if this is a vfork. */
3788 get_last_target_status (&last_ptid, &last);
3790 if (last.kind == TARGET_WAITKIND_FORKED
3791 || last.kind == TARGET_WAITKIND_VFORKED)
3793 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3796 /* Let the arch-specific native code know this process is
3798 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3801 if (forks_exist_p ())
3802 linux_fork_killall ();
3805 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3807 /* Stop all threads before killing them, since ptrace requires
3808 that the thread is stopped to sucessfully PTRACE_KILL. */
3809 iterate_over_lwps (ptid, stop_callback, NULL);
3810 /* ... and wait until all of them have reported back that
3811 they're no longer running. */
3812 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3814 /* Kill all LWP's ... */
3815 iterate_over_lwps (ptid, kill_callback, NULL);
3817 /* ... and wait until we've flushed all events. */
3818 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3821 target_mourn_inferior ();
3825 linux_nat_mourn_inferior (struct target_ops *ops)
3827 int pid = ptid_get_pid (inferior_ptid);
3829 purge_lwp_list (pid);
3831 if (! forks_exist_p ())
3832 /* Normal case, no other forks available. */
3833 linux_ops->to_mourn_inferior (ops);
3835 /* Multi-fork case. The current inferior_ptid has exited, but
3836 there are other viable forks to debug. Delete the exiting
3837 one and context-switch to the first available. */
3838 linux_fork_mourn_inferior ();
3840 /* Let the arch-specific native code know this process is gone. */
3841 linux_nat_forget_process (pid);
3844 /* Convert a native/host siginfo object, into/from the siginfo in the
3845 layout of the inferiors' architecture. */
3848 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3852 if (linux_nat_siginfo_fixup != NULL)
3853 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3855 /* If there was no callback, or the callback didn't do anything,
3856 then just do a straight memcpy. */
3860 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3862 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3866 static enum target_xfer_status
3867 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3868 const char *annex, gdb_byte *readbuf,
3869 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3870 ULONGEST *xfered_len)
3874 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3876 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3877 gdb_assert (readbuf || writebuf);
3879 pid = ptid_get_lwp (inferior_ptid);
3881 pid = ptid_get_pid (inferior_ptid);
3883 if (offset > sizeof (siginfo))
3884 return TARGET_XFER_E_IO;
3887 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3889 return TARGET_XFER_E_IO;
3891 /* When GDB is built as a 64-bit application, ptrace writes into
3892 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3893 inferior with a 64-bit GDB should look the same as debugging it
3894 with a 32-bit GDB, we need to convert it. GDB core always sees
3895 the converted layout, so any read/write will have to be done
3897 siginfo_fixup (&siginfo, inf_siginfo, 0);
3899 if (offset + len > sizeof (siginfo))
3900 len = sizeof (siginfo) - offset;
3902 if (readbuf != NULL)
3903 memcpy (readbuf, inf_siginfo + offset, len);
3906 memcpy (inf_siginfo + offset, writebuf, len);
3908 /* Convert back to ptrace layout before flushing it out. */
3909 siginfo_fixup (&siginfo, inf_siginfo, 1);
3912 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3914 return TARGET_XFER_E_IO;
3918 return TARGET_XFER_OK;
3921 static enum target_xfer_status
3922 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3923 const char *annex, gdb_byte *readbuf,
3924 const gdb_byte *writebuf,
3925 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3927 struct cleanup *old_chain;
3928 enum target_xfer_status xfer;
3930 if (object == TARGET_OBJECT_SIGNAL_INFO)
3931 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3932 offset, len, xfered_len);
3934 /* The target is connected but no live inferior is selected. Pass
3935 this request down to a lower stratum (e.g., the executable
3937 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3938 return TARGET_XFER_EOF;
3940 old_chain = save_inferior_ptid ();
3942 if (ptid_lwp_p (inferior_ptid))
3943 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3945 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3946 offset, len, xfered_len);
3948 do_cleanups (old_chain);
3953 linux_thread_alive (ptid_t ptid)
3957 gdb_assert (ptid_lwp_p (ptid));
3959 /* Send signal 0 instead of anything ptrace, because ptracing a
3960 running thread errors out claiming that the thread doesn't
3962 err = kill_lwp (ptid_get_lwp (ptid), 0);
3964 if (debug_linux_nat)
3965 fprintf_unfiltered (gdb_stdlog,
3966 "LLTA: KILL(SIG0) %s (%s)\n",
3967 target_pid_to_str (ptid),
3968 err ? safe_strerror (tmp_errno) : "OK");
3977 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3979 return linux_thread_alive (ptid);
3983 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3985 static char buf[64];
3987 if (ptid_lwp_p (ptid)
3988 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
3989 || num_lwps (ptid_get_pid (ptid)) > 1))
3991 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
3995 return normal_pid_to_str (ptid);
3999 linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
4001 int pid = ptid_get_pid (thr->ptid);
4002 long lwp = ptid_get_lwp (thr->ptid);
4003 #define FORMAT "/proc/%d/task/%ld/comm"
4004 char buf[sizeof (FORMAT) + 30];
4006 char *result = NULL;
4008 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
4009 comm_file = gdb_fopen_cloexec (buf, "r");
4012 /* Not exported by the kernel, so we define it here. */
4014 static char line[COMM_LEN + 1];
4016 if (fgets (line, sizeof (line), comm_file))
4018 char *nl = strchr (line, '\n');
4035 /* Accepts an integer PID; Returns a string representing a file that
4036 can be opened to get the symbols for the child process. */
4039 linux_child_pid_to_exec_file (struct target_ops *self, int pid)
4041 static char buf[PATH_MAX];
4042 char name[PATH_MAX];
4044 xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
4045 memset (buf, 0, PATH_MAX);
4046 if (readlink (name, buf, PATH_MAX - 1) <= 0)
4052 /* Implement the to_xfer_partial interface for memory reads using the /proc
4053 filesystem. Because we can use a single read() call for /proc, this
4054 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4055 but it doesn't support writes. */
4057 static enum target_xfer_status
4058 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4059 const char *annex, gdb_byte *readbuf,
4060 const gdb_byte *writebuf,
4061 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
4067 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4070 /* Don't bother for one word. */
4071 if (len < 3 * sizeof (long))
4072 return TARGET_XFER_EOF;
4074 /* We could keep this file open and cache it - possibly one per
4075 thread. That requires some juggling, but is even faster. */
4076 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
4077 ptid_get_pid (inferior_ptid));
4078 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
4080 return TARGET_XFER_EOF;
4082 /* If pread64 is available, use it. It's faster if the kernel
4083 supports it (only one syscall), and it's 64-bit safe even on
4084 32-bit platforms (for instance, SPARC debugging a SPARC64
4087 if (pread64 (fd, readbuf, len, offset) != len)
4089 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4098 return TARGET_XFER_EOF;
4102 return TARGET_XFER_OK;
4107 /* Enumerate spufs IDs for process PID. */
4109 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
4111 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4113 LONGEST written = 0;
4116 struct dirent *entry;
4118 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4119 dir = opendir (path);
4124 while ((entry = readdir (dir)) != NULL)
4130 fd = atoi (entry->d_name);
4134 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4135 if (stat (path, &st) != 0)
4137 if (!S_ISDIR (st.st_mode))
4140 if (statfs (path, &stfs) != 0)
4142 if (stfs.f_type != SPUFS_MAGIC)
4145 if (pos >= offset && pos + 4 <= offset + len)
4147 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4157 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4158 object type, using the /proc file system. */
4160 static enum target_xfer_status
4161 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4162 const char *annex, gdb_byte *readbuf,
4163 const gdb_byte *writebuf,
4164 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4169 int pid = ptid_get_pid (inferior_ptid);
4174 return TARGET_XFER_E_IO;
4177 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4180 return TARGET_XFER_E_IO;
4182 return TARGET_XFER_EOF;
4185 *xfered_len = (ULONGEST) l;
4186 return TARGET_XFER_OK;
4191 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4192 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4194 return TARGET_XFER_E_IO;
4197 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4200 return TARGET_XFER_EOF;
4204 ret = write (fd, writebuf, (size_t) len);
4206 ret = read (fd, readbuf, (size_t) len);
4211 return TARGET_XFER_E_IO;
4213 return TARGET_XFER_EOF;
4216 *xfered_len = (ULONGEST) ret;
4217 return TARGET_XFER_OK;
4222 /* Parse LINE as a signal set and add its set bits to SIGS. */
4225 add_line_to_sigset (const char *line, sigset_t *sigs)
4227 int len = strlen (line) - 1;
4231 if (line[len] != '\n')
4232 error (_("Could not parse signal set: %s"), line);
4240 if (*p >= '0' && *p <= '9')
4242 else if (*p >= 'a' && *p <= 'f')
4243 digit = *p - 'a' + 10;
4245 error (_("Could not parse signal set: %s"), line);
4250 sigaddset (sigs, signum + 1);
4252 sigaddset (sigs, signum + 2);
4254 sigaddset (sigs, signum + 3);
4256 sigaddset (sigs, signum + 4);
4262 /* Find process PID's pending signals from /proc/pid/status and set
4266 linux_proc_pending_signals (int pid, sigset_t *pending,
4267 sigset_t *blocked, sigset_t *ignored)
4270 char buffer[PATH_MAX], fname[PATH_MAX];
4271 struct cleanup *cleanup;
4273 sigemptyset (pending);
4274 sigemptyset (blocked);
4275 sigemptyset (ignored);
4276 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4277 procfile = gdb_fopen_cloexec (fname, "r");
4278 if (procfile == NULL)
4279 error (_("Could not open %s"), fname);
4280 cleanup = make_cleanup_fclose (procfile);
4282 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4284 /* Normal queued signals are on the SigPnd line in the status
4285 file. However, 2.6 kernels also have a "shared" pending
4286 queue for delivering signals to a thread group, so check for
4289 Unfortunately some Red Hat kernels include the shared pending
4290 queue but not the ShdPnd status field. */
4292 if (startswith (buffer, "SigPnd:\t"))
4293 add_line_to_sigset (buffer + 8, pending);
4294 else if (startswith (buffer, "ShdPnd:\t"))
4295 add_line_to_sigset (buffer + 8, pending);
4296 else if (startswith (buffer, "SigBlk:\t"))
4297 add_line_to_sigset (buffer + 8, blocked);
4298 else if (startswith (buffer, "SigIgn:\t"))
4299 add_line_to_sigset (buffer + 8, ignored);
4302 do_cleanups (cleanup);
4305 static enum target_xfer_status
4306 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4307 const char *annex, gdb_byte *readbuf,
4308 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4309 ULONGEST *xfered_len)
4311 gdb_assert (object == TARGET_OBJECT_OSDATA);
4313 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4314 if (*xfered_len == 0)
4315 return TARGET_XFER_EOF;
4317 return TARGET_XFER_OK;
4320 static enum target_xfer_status
4321 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4322 const char *annex, gdb_byte *readbuf,
4323 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4324 ULONGEST *xfered_len)
4326 enum target_xfer_status xfer;
4328 if (object == TARGET_OBJECT_AUXV)
4329 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4330 offset, len, xfered_len);
4332 if (object == TARGET_OBJECT_OSDATA)
4333 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4334 offset, len, xfered_len);
4336 if (object == TARGET_OBJECT_SPU)
4337 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4338 offset, len, xfered_len);
4340 /* GDB calculates all the addresses in possibly larget width of the address.
4341 Address width needs to be masked before its final use - either by
4342 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4344 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4346 if (object == TARGET_OBJECT_MEMORY)
4348 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4350 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4351 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4354 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4355 offset, len, xfered_len);
4356 if (xfer != TARGET_XFER_EOF)
4359 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4360 offset, len, xfered_len);
4364 cleanup_target_stop (void *arg)
4366 ptid_t *ptid = (ptid_t *) arg;
4368 gdb_assert (arg != NULL);
4371 target_resume (*ptid, 0, GDB_SIGNAL_0);
4374 static VEC(static_tracepoint_marker_p) *
4375 linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
4378 char s[IPA_CMD_BUF_SIZE];
4379 struct cleanup *old_chain;
4380 int pid = ptid_get_pid (inferior_ptid);
4381 VEC(static_tracepoint_marker_p) *markers = NULL;
4382 struct static_tracepoint_marker *marker = NULL;
4384 ptid_t ptid = ptid_build (pid, 0, 0);
4389 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4390 s[sizeof ("qTfSTM")] = 0;
4392 agent_run_command (pid, s, strlen (s) + 1);
4394 old_chain = make_cleanup (free_current_marker, &marker);
4395 make_cleanup (cleanup_target_stop, &ptid);
4400 marker = XCNEW (struct static_tracepoint_marker);
4404 parse_static_tracepoint_marker_definition (p, &p, marker);
4406 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4408 VEC_safe_push (static_tracepoint_marker_p,
4414 release_static_tracepoint_marker (marker);
4415 memset (marker, 0, sizeof (*marker));
4418 while (*p++ == ','); /* comma-separated list */
4420 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4421 s[sizeof ("qTsSTM")] = 0;
4422 agent_run_command (pid, s, strlen (s) + 1);
4426 do_cleanups (old_chain);
4431 /* Create a prototype generic GNU/Linux target. The client can override
4432 it with local methods. */
4435 linux_target_install_ops (struct target_ops *t)
4437 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4438 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4439 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4440 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4441 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4442 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4443 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4444 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4445 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4446 t->to_post_attach = linux_child_post_attach;
4447 t->to_follow_fork = linux_child_follow_fork;
4449 super_xfer_partial = t->to_xfer_partial;
4450 t->to_xfer_partial = linux_xfer_partial;
4452 t->to_static_tracepoint_markers_by_strid
4453 = linux_child_static_tracepoint_markers_by_strid;
4459 struct target_ops *t;
4461 t = inf_ptrace_target ();
4462 linux_target_install_ops (t);
4468 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4470 struct target_ops *t;
4472 t = inf_ptrace_trad_target (register_u_offset);
4473 linux_target_install_ops (t);
4478 /* target_is_async_p implementation. */
4481 linux_nat_is_async_p (struct target_ops *ops)
4483 return linux_is_async_p ();
4486 /* target_can_async_p implementation. */
4489 linux_nat_can_async_p (struct target_ops *ops)
4491 /* NOTE: palves 2008-03-21: We're only async when the user requests
4492 it explicitly with the "set target-async" command.
4493 Someday, linux will always be async. */
4494 return target_async_permitted;
4498 linux_nat_supports_non_stop (struct target_ops *self)
4503 /* True if we want to support multi-process. To be removed when GDB
4504 supports multi-exec. */
4506 int linux_multi_process = 1;
4509 linux_nat_supports_multi_process (struct target_ops *self)
4511 return linux_multi_process;
4515 linux_nat_supports_disable_randomization (struct target_ops *self)
4517 #ifdef HAVE_PERSONALITY
4524 static int async_terminal_is_ours = 1;
4526 /* target_terminal_inferior implementation.
4528 This is a wrapper around child_terminal_inferior to add async support. */
4531 linux_nat_terminal_inferior (struct target_ops *self)
4533 /* Like target_terminal_inferior, use target_can_async_p, not
4534 target_is_async_p, since at this point the target is not async
4535 yet. If it can async, then we know it will become async prior to
4537 if (!target_can_async_p ())
4539 /* Async mode is disabled. */
4540 child_terminal_inferior (self);
4544 child_terminal_inferior (self);
4546 /* Calls to target_terminal_*() are meant to be idempotent. */
4547 if (!async_terminal_is_ours)
4550 delete_file_handler (input_fd);
4551 async_terminal_is_ours = 0;
4555 /* target_terminal_ours implementation.
4557 This is a wrapper around child_terminal_ours to add async support (and
4558 implement the target_terminal_ours vs target_terminal_ours_for_output
4559 distinction). child_terminal_ours is currently no different than
4560 child_terminal_ours_for_output.
4561 We leave target_terminal_ours_for_output alone, leaving it to
4562 child_terminal_ours_for_output. */
4565 linux_nat_terminal_ours (struct target_ops *self)
4567 /* GDB should never give the terminal to the inferior if the
4568 inferior is running in the background (run&, continue&, etc.),
4569 but claiming it sure should. */
4570 child_terminal_ours (self);
4572 if (async_terminal_is_ours)
4575 clear_sigint_trap ();
4576 add_file_handler (input_fd, stdin_event_handler, 0);
4577 async_terminal_is_ours = 1;
4580 static void (*async_client_callback) (enum inferior_event_type event_type,
4582 static void *async_client_context;
4584 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4585 so we notice when any child changes state, and notify the
4586 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4587 above to wait for the arrival of a SIGCHLD. */
4590 sigchld_handler (int signo)
4592 int old_errno = errno;
4594 if (debug_linux_nat)
4595 ui_file_write_async_safe (gdb_stdlog,
4596 "sigchld\n", sizeof ("sigchld\n") - 1);
4598 if (signo == SIGCHLD
4599 && linux_nat_event_pipe[0] != -1)
4600 async_file_mark (); /* Let the event loop know that there are
4601 events to handle. */
4606 /* Callback registered with the target events file descriptor. */
4609 handle_target_event (int error, gdb_client_data client_data)
4611 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4614 /* Create/destroy the target events pipe. Returns previous state. */
4617 linux_async_pipe (int enable)
4619 int previous = linux_is_async_p ();
4621 if (previous != enable)
4625 /* Block child signals while we create/destroy the pipe, as
4626 their handler writes to it. */
4627 block_child_signals (&prev_mask);
4631 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4632 internal_error (__FILE__, __LINE__,
4633 "creating event pipe failed.");
4635 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4636 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4640 close (linux_nat_event_pipe[0]);
4641 close (linux_nat_event_pipe[1]);
4642 linux_nat_event_pipe[0] = -1;
4643 linux_nat_event_pipe[1] = -1;
4646 restore_child_signals_mask (&prev_mask);
4652 /* target_async implementation. */
4655 linux_nat_async (struct target_ops *ops,
4656 void (*callback) (enum inferior_event_type event_type,
4660 if (callback != NULL)
4662 async_client_callback = callback;
4663 async_client_context = context;
4664 if (!linux_async_pipe (1))
4666 add_file_handler (linux_nat_event_pipe[0],
4667 handle_target_event, NULL);
4668 /* There may be pending events to handle. Tell the event loop
4675 async_client_callback = callback;
4676 async_client_context = context;
4677 delete_file_handler (linux_nat_event_pipe[0]);
4678 linux_async_pipe (0);
4683 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4687 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4691 if (debug_linux_nat)
4692 fprintf_unfiltered (gdb_stdlog,
4693 "LNSL: running -> suspending %s\n",
4694 target_pid_to_str (lwp->ptid));
4697 if (lwp->last_resume_kind == resume_stop)
4699 if (debug_linux_nat)
4700 fprintf_unfiltered (gdb_stdlog,
4701 "linux-nat: already stopping LWP %ld at "
4703 ptid_get_lwp (lwp->ptid));
4707 stop_callback (lwp, NULL);
4708 lwp->last_resume_kind = resume_stop;
4712 /* Already known to be stopped; do nothing. */
4714 if (debug_linux_nat)
4716 if (find_thread_ptid (lwp->ptid)->stop_requested)
4717 fprintf_unfiltered (gdb_stdlog,
4718 "LNSL: already stopped/stop_requested %s\n",
4719 target_pid_to_str (lwp->ptid));
4721 fprintf_unfiltered (gdb_stdlog,
4722 "LNSL: already stopped/no "
4723 "stop_requested yet %s\n",
4724 target_pid_to_str (lwp->ptid));
4731 linux_nat_stop (struct target_ops *self, ptid_t ptid)
4734 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4736 linux_ops->to_stop (linux_ops, ptid);
4740 linux_nat_close (struct target_ops *self)
4742 /* Unregister from the event loop. */
4743 if (linux_nat_is_async_p (self))
4744 linux_nat_async (self, NULL, NULL);
4746 if (linux_ops->to_close)
4747 linux_ops->to_close (linux_ops);
4752 /* When requests are passed down from the linux-nat layer to the
4753 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4754 used. The address space pointer is stored in the inferior object,
4755 but the common code that is passed such ptid can't tell whether
4756 lwpid is a "main" process id or not (it assumes so). We reverse
4757 look up the "main" process id from the lwp here. */
4759 static struct address_space *
4760 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4762 struct lwp_info *lwp;
4763 struct inferior *inf;
4766 if (ptid_get_lwp (ptid) == 0)
4768 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4770 lwp = find_lwp_pid (ptid);
4771 pid = ptid_get_pid (lwp->ptid);
4775 /* A (pid,lwpid,0) ptid. */
4776 pid = ptid_get_pid (ptid);
4779 inf = find_inferior_pid (pid);
4780 gdb_assert (inf != NULL);
4784 /* Return the cached value of the processor core for thread PTID. */
4787 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4789 struct lwp_info *info = find_lwp_pid (ptid);
4797 linux_nat_add_target (struct target_ops *t)
4799 /* Save the provided single-threaded target. We save this in a separate
4800 variable because another target we've inherited from (e.g. inf-ptrace)
4801 may have saved a pointer to T; we want to use it for the final
4802 process stratum target. */
4803 linux_ops_saved = *t;
4804 linux_ops = &linux_ops_saved;
4806 /* Override some methods for multithreading. */
4807 t->to_create_inferior = linux_nat_create_inferior;
4808 t->to_attach = linux_nat_attach;
4809 t->to_detach = linux_nat_detach;
4810 t->to_resume = linux_nat_resume;
4811 t->to_wait = linux_nat_wait;
4812 t->to_pass_signals = linux_nat_pass_signals;
4813 t->to_xfer_partial = linux_nat_xfer_partial;
4814 t->to_kill = linux_nat_kill;
4815 t->to_mourn_inferior = linux_nat_mourn_inferior;
4816 t->to_thread_alive = linux_nat_thread_alive;
4817 t->to_pid_to_str = linux_nat_pid_to_str;
4818 t->to_thread_name = linux_nat_thread_name;
4819 t->to_has_thread_control = tc_schedlock;
4820 t->to_thread_address_space = linux_nat_thread_address_space;
4821 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4822 t->to_stopped_data_address = linux_nat_stopped_data_address;
4823 t->to_stopped_by_sw_breakpoint = linux_nat_stopped_by_sw_breakpoint;
4824 t->to_supports_stopped_by_sw_breakpoint = linux_nat_supports_stopped_by_sw_breakpoint;
4825 t->to_stopped_by_hw_breakpoint = linux_nat_stopped_by_hw_breakpoint;
4826 t->to_supports_stopped_by_hw_breakpoint = linux_nat_supports_stopped_by_hw_breakpoint;
4828 t->to_can_async_p = linux_nat_can_async_p;
4829 t->to_is_async_p = linux_nat_is_async_p;
4830 t->to_supports_non_stop = linux_nat_supports_non_stop;
4831 t->to_async = linux_nat_async;
4832 t->to_terminal_inferior = linux_nat_terminal_inferior;
4833 t->to_terminal_ours = linux_nat_terminal_ours;
4835 super_close = t->to_close;
4836 t->to_close = linux_nat_close;
4838 /* Methods for non-stop support. */
4839 t->to_stop = linux_nat_stop;
4841 t->to_supports_multi_process = linux_nat_supports_multi_process;
4843 t->to_supports_disable_randomization
4844 = linux_nat_supports_disable_randomization;
4846 t->to_core_of_thread = linux_nat_core_of_thread;
4848 /* We don't change the stratum; this target will sit at
4849 process_stratum and thread_db will set at thread_stratum. This
4850 is a little strange, since this is a multi-threaded-capable
4851 target, but we want to be on the stack below thread_db, and we
4852 also want to be used for single-threaded processes. */
4857 /* Register a method to call whenever a new thread is attached. */
4859 linux_nat_set_new_thread (struct target_ops *t,
4860 void (*new_thread) (struct lwp_info *))
4862 /* Save the pointer. We only support a single registered instance
4863 of the GNU/Linux native target, so we do not need to map this to
4865 linux_nat_new_thread = new_thread;
4868 /* See declaration in linux-nat.h. */
4871 linux_nat_set_new_fork (struct target_ops *t,
4872 linux_nat_new_fork_ftype *new_fork)
4874 /* Save the pointer. */
4875 linux_nat_new_fork = new_fork;
4878 /* See declaration in linux-nat.h. */
4881 linux_nat_set_forget_process (struct target_ops *t,
4882 linux_nat_forget_process_ftype *fn)
4884 /* Save the pointer. */
4885 linux_nat_forget_process_hook = fn;
4888 /* See declaration in linux-nat.h. */
4891 linux_nat_forget_process (pid_t pid)
4893 if (linux_nat_forget_process_hook != NULL)
4894 linux_nat_forget_process_hook (pid);
4897 /* Register a method that converts a siginfo object between the layout
4898 that ptrace returns, and the layout in the architecture of the
4901 linux_nat_set_siginfo_fixup (struct target_ops *t,
4902 int (*siginfo_fixup) (siginfo_t *,
4906 /* Save the pointer. */
4907 linux_nat_siginfo_fixup = siginfo_fixup;
4910 /* Register a method to call prior to resuming a thread. */
4913 linux_nat_set_prepare_to_resume (struct target_ops *t,
4914 void (*prepare_to_resume) (struct lwp_info *))
4916 /* Save the pointer. */
4917 linux_nat_prepare_to_resume = prepare_to_resume;
4920 /* See linux-nat.h. */
4923 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4927 pid = ptid_get_lwp (ptid);
4929 pid = ptid_get_pid (ptid);
4932 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4935 memset (siginfo, 0, sizeof (*siginfo));
4941 /* See nat/linux-nat.h. */
4944 current_lwp_ptid (void)
4946 gdb_assert (ptid_lwp_p (inferior_ptid));
4947 return inferior_ptid;
4950 /* Provide a prototype to silence -Wmissing-prototypes. */
4951 extern initialize_file_ftype _initialize_linux_nat;
4954 _initialize_linux_nat (void)
4956 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4957 &debug_linux_nat, _("\
4958 Set debugging of GNU/Linux lwp module."), _("\
4959 Show debugging of GNU/Linux lwp module."), _("\
4960 Enables printf debugging output."),
4962 show_debug_linux_nat,
4963 &setdebuglist, &showdebuglist);
4965 /* Save this mask as the default. */
4966 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4968 /* Install a SIGCHLD handler. */
4969 sigchld_action.sa_handler = sigchld_handler;
4970 sigemptyset (&sigchld_action.sa_mask);
4971 sigchld_action.sa_flags = SA_RESTART;
4973 /* Make it the default. */
4974 sigaction (SIGCHLD, &sigchld_action, NULL);
4976 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4977 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
4978 sigdelset (&suspend_mask, SIGCHLD);
4980 sigemptyset (&blocked_mask);
4982 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
4983 support read-only process state. */
4984 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
4985 | PTRACE_O_TRACEVFORKDONE
4986 | PTRACE_O_TRACEVFORK
4987 | PTRACE_O_TRACEFORK
4988 | PTRACE_O_TRACEEXEC);
4992 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4993 the GNU/Linux Threads library and therefore doesn't really belong
4996 /* Read variable NAME in the target and return its value if found.
4997 Otherwise return zero. It is assumed that the type of the variable
5001 get_signo (const char *name)
5003 struct bound_minimal_symbol ms;
5006 ms = lookup_minimal_symbol (name, NULL, NULL);
5007 if (ms.minsym == NULL)
5010 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
5011 sizeof (signo)) != 0)
5017 /* Return the set of signals used by the threads library in *SET. */
5020 lin_thread_get_thread_signals (sigset_t *set)
5022 struct sigaction action;
5023 int restart, cancel;
5025 sigemptyset (&blocked_mask);
5028 restart = get_signo ("__pthread_sig_restart");
5029 cancel = get_signo ("__pthread_sig_cancel");
5031 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5032 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5033 not provide any way for the debugger to query the signal numbers -
5034 fortunately they don't change! */
5037 restart = __SIGRTMIN;
5040 cancel = __SIGRTMIN + 1;
5042 sigaddset (set, restart);
5043 sigaddset (set, cancel);
5045 /* The GNU/Linux Threads library makes terminating threads send a
5046 special "cancel" signal instead of SIGCHLD. Make sure we catch
5047 those (to prevent them from terminating GDB itself, which is
5048 likely to be their default action) and treat them the same way as
5051 action.sa_handler = sigchld_handler;
5052 sigemptyset (&action.sa_mask);
5053 action.sa_flags = SA_RESTART;
5054 sigaction (cancel, &action, NULL);
5056 /* We block the "cancel" signal throughout this code ... */
5057 sigaddset (&blocked_mask, cancel);
5058 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
5060 /* ... except during a sigsuspend. */
5061 sigdelset (&suspend_mask, cancel);