1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2016 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"
28 #include <sys/syscall.h>
29 #include "nat/gdb_ptrace.h"
30 #include "linux-nat.h"
31 #include "nat/linux-ptrace.h"
32 #include "nat/linux-procfs.h"
33 #include "nat/linux-personality.h"
34 #include "linux-fork.h"
35 #include "gdbthread.h"
39 #include "inf-child.h"
40 #include "inf-ptrace.h"
42 #include <sys/procfs.h> /* for elf_gregset etc. */
43 #include "elf-bfd.h" /* for elfcore_write_* */
44 #include "gregset.h" /* for gregset */
45 #include "gdbcore.h" /* for get_exec_file */
46 #include <ctype.h> /* for isdigit */
47 #include <sys/stat.h> /* for struct stat */
48 #include <fcntl.h> /* for O_RDONLY */
50 #include "event-loop.h"
51 #include "event-top.h"
53 #include <sys/types.h>
55 #include "xml-support.h"
58 #include "nat/linux-osdata.h"
59 #include "linux-tdep.h"
62 #include "tracepoint.h"
64 #include "target-descriptions.h"
65 #include "filestuff.h"
67 #include "nat/linux-namespaces.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,
80 passing the specific pid, and not passing WNOHANG.
82 When waiting for an event in all threads, waitpid is not quite good:
84 - If the thread group leader exits while other threads in the thread
85 group still exist, waitpid(TGID, ...) hangs. That waitpid won't
86 return an exit status until the other threads in the group are
89 - When a non-leader thread execs, that thread just vanishes without
90 reporting an exit (so we'd hang if we waited for it explicitly in
91 that case). The exec event is instead reported to the TGID pid.
93 The solution is to always use -1 and WNOHANG, together with
96 First, we use non-blocking waitpid to check for events. If nothing is
97 found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives,
98 it means something happened to a child process. As soon as we know
99 there's an event, we get back to calling nonblocking waitpid.
101 Note that SIGCHLD should be blocked between waitpid and sigsuspend
102 calls, so that we don't miss a signal. If SIGCHLD arrives in between,
103 when it's blocked, the signal becomes pending and sigsuspend
104 immediately notices it and returns.
106 Waiting for events in async mode (TARGET_WNOHANG)
107 =================================================
109 In async mode, GDB should always be ready to handle both user input
110 and target events, so neither blocking waitpid nor sigsuspend are
111 viable options. Instead, we should asynchronously notify the GDB main
112 event loop whenever there's an unprocessed event from the target. We
113 detect asynchronous target events by handling SIGCHLD signals. To
114 notify the event loop about target events, the self-pipe trick is used
115 --- a pipe is registered as waitable event source in the event loop,
116 the event loop select/poll's on the read end of this pipe (as well on
117 other event sources, e.g., stdin), and the SIGCHLD handler writes a
118 byte to this pipe. This is more portable than relying on
119 pselect/ppoll, since on kernels that lack those syscalls, libc
120 emulates them with select/poll+sigprocmask, and that is racy
121 (a.k.a. plain broken).
123 Obviously, if we fail to notify the event loop if there's a target
124 event, it's bad. OTOH, if we notify the event loop when there's no
125 event from the target, linux_nat_wait will detect that there's no real
126 event to report, and return event of type TARGET_WAITKIND_IGNORE.
127 This is mostly harmless, but it will waste time and is better avoided.
129 The main design point is that every time GDB is outside linux-nat.c,
130 we have a SIGCHLD handler installed that is called when something
131 happens to the target and notifies the GDB event loop. Whenever GDB
132 core decides to handle the event, and calls into linux-nat.c, we
133 process things as in sync mode, except that the we never block in
136 While processing an event, we may end up momentarily blocked in
137 waitpid calls. Those waitpid calls, while blocking, are guarantied to
138 return quickly. E.g., in all-stop mode, before reporting to the core
139 that an LWP hit a breakpoint, all LWPs are stopped by sending them
140 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
141 Note that this is different from blocking indefinitely waiting for the
142 next event --- here, we're already handling an event.
147 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
148 signal is not entirely significant; we just need for a signal to be delivered,
149 so that we can intercept it. SIGSTOP's advantage is that it can not be
150 blocked. A disadvantage is that it is not a real-time signal, so it can only
151 be queued once; we do not keep track of other sources of SIGSTOP.
153 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
154 use them, because they have special behavior when the signal is generated -
155 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
156 kills the entire thread group.
158 A delivered SIGSTOP would stop the entire thread group, not just the thread we
159 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
160 cancel it (by PTRACE_CONT without passing SIGSTOP).
162 We could use a real-time signal instead. This would solve those problems; we
163 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
164 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
165 generates it, and there are races with trying to find a signal that is not
171 The case of a thread group (process) with 3 or more threads, and a
172 thread other than the leader execs is worth detailing:
174 On an exec, the Linux kernel destroys all threads except the execing
175 one in the thread group, and resets the execing thread's tid to the
176 tgid. No exit notification is sent for the execing thread -- from the
177 ptracer's perspective, it appears as though the execing thread just
178 vanishes. Until we reap all other threads except the leader and the
179 execing thread, the leader will be zombie, and the execing thread will
180 be in `D (disc sleep)' state. As soon as all other threads are
181 reaped, the execing thread changes its tid to the tgid, and the
182 previous (zombie) leader vanishes, giving place to the "new"
186 #define O_LARGEFILE 0
189 /* Does the current host support PTRACE_GETREGSET? */
190 enum tribool have_ptrace_getregset = TRIBOOL_UNKNOWN;
192 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
193 the use of the multi-threaded target. */
194 static struct target_ops *linux_ops;
195 static struct target_ops linux_ops_saved;
197 /* The method to call, if any, when a new thread is attached. */
198 static void (*linux_nat_new_thread) (struct lwp_info *);
200 /* The method to call, if any, when a new fork is attached. */
201 static linux_nat_new_fork_ftype *linux_nat_new_fork;
203 /* The method to call, if any, when a process is no longer
205 static linux_nat_forget_process_ftype *linux_nat_forget_process_hook;
207 /* Hook to call prior to resuming a thread. */
208 static void (*linux_nat_prepare_to_resume) (struct lwp_info *);
210 /* The method to call, if any, when the siginfo object needs to be
211 converted between the layout returned by ptrace, and the layout in
212 the architecture of the inferior. */
213 static int (*linux_nat_siginfo_fixup) (siginfo_t *,
217 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
218 Called by our to_xfer_partial. */
219 static target_xfer_partial_ftype *super_xfer_partial;
221 /* The saved to_close method, inherited from inf-ptrace.c.
222 Called by our to_close. */
223 static void (*super_close) (struct target_ops *);
225 static unsigned int debug_linux_nat;
227 show_debug_linux_nat (struct ui_file *file, int from_tty,
228 struct cmd_list_element *c, const char *value)
230 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
234 struct simple_pid_list
238 struct simple_pid_list *next;
240 struct simple_pid_list *stopped_pids;
242 /* Whether target_thread_events is in effect. */
243 static int report_thread_events;
245 /* Async mode support. */
247 /* The read/write ends of the pipe registered as waitable file in the
249 static int linux_nat_event_pipe[2] = { -1, -1 };
251 /* True if we're currently in async mode. */
252 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
254 /* Flush the event pipe. */
257 async_file_flush (void)
264 ret = read (linux_nat_event_pipe[0], &buf, 1);
266 while (ret >= 0 || (ret == -1 && errno == EINTR));
269 /* Put something (anything, doesn't matter what, or how much) in event
270 pipe, so that the select/poll in the event-loop realizes we have
271 something to process. */
274 async_file_mark (void)
278 /* It doesn't really matter what the pipe contains, as long we end
279 up with something in it. Might as well flush the previous
285 ret = write (linux_nat_event_pipe[1], "+", 1);
287 while (ret == -1 && errno == EINTR);
289 /* Ignore EAGAIN. If the pipe is full, the event loop will already
290 be awakened anyway. */
293 static int kill_lwp (int lwpid, int signo);
295 static int stop_callback (struct lwp_info *lp, void *data);
296 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
298 static void block_child_signals (sigset_t *prev_mask);
299 static void restore_child_signals_mask (sigset_t *prev_mask);
302 static struct lwp_info *add_lwp (ptid_t ptid);
303 static void purge_lwp_list (int pid);
304 static void delete_lwp (ptid_t ptid);
305 static struct lwp_info *find_lwp_pid (ptid_t ptid);
307 static int lwp_status_pending_p (struct lwp_info *lp);
309 static int sigtrap_is_event (int status);
310 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
312 static void save_stop_reason (struct lwp_info *lp);
317 /* See nat/linux-nat.h. */
320 ptid_of_lwp (struct lwp_info *lwp)
325 /* See nat/linux-nat.h. */
328 lwp_set_arch_private_info (struct lwp_info *lwp,
329 struct arch_lwp_info *info)
331 lwp->arch_private = info;
334 /* See nat/linux-nat.h. */
336 struct arch_lwp_info *
337 lwp_arch_private_info (struct lwp_info *lwp)
339 return lwp->arch_private;
342 /* See nat/linux-nat.h. */
345 lwp_is_stopped (struct lwp_info *lwp)
350 /* See nat/linux-nat.h. */
352 enum target_stop_reason
353 lwp_stop_reason (struct lwp_info *lwp)
355 return lwp->stop_reason;
359 /* Trivial list manipulation functions to keep track of a list of
360 new stopped processes. */
362 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
364 struct simple_pid_list *new_pid = XNEW (struct simple_pid_list);
367 new_pid->status = status;
368 new_pid->next = *listp;
373 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
375 struct simple_pid_list **p;
377 for (p = listp; *p != NULL; p = &(*p)->next)
378 if ((*p)->pid == pid)
380 struct simple_pid_list *next = (*p)->next;
382 *statusp = (*p)->status;
390 /* Return the ptrace options that we want to try to enable. */
393 linux_nat_ptrace_options (int attached)
398 options |= PTRACE_O_EXITKILL;
400 options |= (PTRACE_O_TRACESYSGOOD
401 | PTRACE_O_TRACEVFORKDONE
402 | PTRACE_O_TRACEVFORK
404 | PTRACE_O_TRACEEXEC);
409 /* Initialize ptrace warnings and check for supported ptrace
412 ATTACHED should be nonzero iff we attached to the inferior. */
415 linux_init_ptrace (pid_t pid, int attached)
417 int options = linux_nat_ptrace_options (attached);
419 linux_enable_event_reporting (pid, options);
420 linux_ptrace_init_warnings ();
424 linux_child_post_attach (struct target_ops *self, int pid)
426 linux_init_ptrace (pid, 1);
430 linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
432 linux_init_ptrace (ptid_get_pid (ptid), 0);
435 /* Return the number of known LWPs in the tgid given by PID. */
443 for (lp = lwp_list; lp; lp = lp->next)
444 if (ptid_get_pid (lp->ptid) == pid)
450 /* Call delete_lwp with prototype compatible for make_cleanup. */
453 delete_lwp_cleanup (void *lp_voidp)
455 struct lwp_info *lp = (struct lwp_info *) lp_voidp;
457 delete_lwp (lp->ptid);
460 /* Target hook for follow_fork. On entry inferior_ptid must be the
461 ptid of the followed inferior. At return, inferior_ptid will be
465 linux_child_follow_fork (struct target_ops *ops, int follow_child,
470 struct lwp_info *child_lp = NULL;
471 int status = W_STOPCODE (0);
472 struct cleanup *old_chain;
474 ptid_t parent_ptid, child_ptid;
475 int parent_pid, child_pid;
477 has_vforked = (inferior_thread ()->pending_follow.kind
478 == TARGET_WAITKIND_VFORKED);
479 parent_ptid = inferior_ptid;
480 child_ptid = inferior_thread ()->pending_follow.value.related_pid;
481 parent_pid = ptid_get_lwp (parent_ptid);
482 child_pid = ptid_get_lwp (child_ptid);
484 /* We're already attached to the parent, by default. */
485 old_chain = save_inferior_ptid ();
486 inferior_ptid = child_ptid;
487 child_lp = add_lwp (inferior_ptid);
488 child_lp->stopped = 1;
489 child_lp->last_resume_kind = resume_stop;
491 /* Detach new forked process? */
494 make_cleanup (delete_lwp_cleanup, child_lp);
496 if (linux_nat_prepare_to_resume != NULL)
497 linux_nat_prepare_to_resume (child_lp);
499 /* When debugging an inferior in an architecture that supports
500 hardware single stepping on a kernel without commit
501 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
502 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
503 set if the parent process had them set.
504 To work around this, single step the child process
505 once before detaching to clear the flags. */
507 if (!gdbarch_software_single_step_p (target_thread_architecture
510 linux_disable_event_reporting (child_pid);
511 if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
512 perror_with_name (_("Couldn't do single step"));
513 if (my_waitpid (child_pid, &status, 0) < 0)
514 perror_with_name (_("Couldn't wait vfork process"));
517 if (WIFSTOPPED (status))
521 signo = WSTOPSIG (status);
523 && !signal_pass_state (gdb_signal_from_host (signo)))
525 ptrace (PTRACE_DETACH, child_pid, 0, signo);
528 /* Resets value of inferior_ptid to parent ptid. */
529 do_cleanups (old_chain);
533 /* Let the thread_db layer learn about this new process. */
534 check_for_thread_db ();
537 do_cleanups (old_chain);
541 struct lwp_info *parent_lp;
543 parent_lp = find_lwp_pid (parent_ptid);
544 gdb_assert (linux_supports_tracefork () >= 0);
546 if (linux_supports_tracevforkdone ())
549 fprintf_unfiltered (gdb_stdlog,
550 "LCFF: waiting for VFORK_DONE on %d\n",
552 parent_lp->stopped = 1;
554 /* We'll handle the VFORK_DONE event like any other
555 event, in target_wait. */
559 /* We can't insert breakpoints until the child has
560 finished with the shared memory region. We need to
561 wait until that happens. Ideal would be to just
563 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
564 - waitpid (parent_pid, &status, __WALL);
565 However, most architectures can't handle a syscall
566 being traced on the way out if it wasn't traced on
569 We might also think to loop, continuing the child
570 until it exits or gets a SIGTRAP. One problem is
571 that the child might call ptrace with PTRACE_TRACEME.
573 There's no simple and reliable way to figure out when
574 the vforked child will be done with its copy of the
575 shared memory. We could step it out of the syscall,
576 two instructions, let it go, and then single-step the
577 parent once. When we have hardware single-step, this
578 would work; with software single-step it could still
579 be made to work but we'd have to be able to insert
580 single-step breakpoints in the child, and we'd have
581 to insert -just- the single-step breakpoint in the
582 parent. Very awkward.
584 In the end, the best we can do is to make sure it
585 runs for a little while. Hopefully it will be out of
586 range of any breakpoints we reinsert. Usually this
587 is only the single-step breakpoint at vfork's return
591 fprintf_unfiltered (gdb_stdlog,
592 "LCFF: no VFORK_DONE "
593 "support, sleeping a bit\n");
597 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
598 and leave it pending. The next linux_nat_resume call
599 will notice a pending event, and bypasses actually
600 resuming the inferior. */
601 parent_lp->status = 0;
602 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
603 parent_lp->stopped = 1;
605 /* If we're in async mode, need to tell the event loop
606 there's something here to process. */
607 if (target_is_async_p ())
614 struct lwp_info *child_lp;
616 child_lp = add_lwp (inferior_ptid);
617 child_lp->stopped = 1;
618 child_lp->last_resume_kind = resume_stop;
620 /* Let the thread_db layer learn about this new process. */
621 check_for_thread_db ();
629 linux_child_insert_fork_catchpoint (struct target_ops *self, int pid)
631 return !linux_supports_tracefork ();
635 linux_child_remove_fork_catchpoint (struct target_ops *self, int pid)
641 linux_child_insert_vfork_catchpoint (struct target_ops *self, int pid)
643 return !linux_supports_tracefork ();
647 linux_child_remove_vfork_catchpoint (struct target_ops *self, int pid)
653 linux_child_insert_exec_catchpoint (struct target_ops *self, int pid)
655 return !linux_supports_tracefork ();
659 linux_child_remove_exec_catchpoint (struct target_ops *self, int pid)
665 linux_child_set_syscall_catchpoint (struct target_ops *self,
666 int pid, int needed, int any_count,
667 int table_size, int *table)
669 if (!linux_supports_tracesysgood ())
672 /* On GNU/Linux, we ignore the arguments. It means that we only
673 enable the syscall catchpoints, but do not disable them.
675 Also, we do not use the `table' information because we do not
676 filter system calls here. We let GDB do the logic for us. */
680 /* List of known LWPs. */
681 struct lwp_info *lwp_list;
684 /* Original signal mask. */
685 static sigset_t normal_mask;
687 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
688 _initialize_linux_nat. */
689 static sigset_t suspend_mask;
691 /* Signals to block to make that sigsuspend work. */
692 static sigset_t blocked_mask;
694 /* SIGCHLD action. */
695 struct sigaction sigchld_action;
697 /* Block child signals (SIGCHLD and linux threads signals), and store
698 the previous mask in PREV_MASK. */
701 block_child_signals (sigset_t *prev_mask)
703 /* Make sure SIGCHLD is blocked. */
704 if (!sigismember (&blocked_mask, SIGCHLD))
705 sigaddset (&blocked_mask, SIGCHLD);
707 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
710 /* Restore child signals mask, previously returned by
711 block_child_signals. */
714 restore_child_signals_mask (sigset_t *prev_mask)
716 sigprocmask (SIG_SETMASK, prev_mask, NULL);
719 /* Mask of signals to pass directly to the inferior. */
720 static sigset_t pass_mask;
722 /* Update signals to pass to the inferior. */
724 linux_nat_pass_signals (struct target_ops *self,
725 int numsigs, unsigned char *pass_signals)
729 sigemptyset (&pass_mask);
731 for (signo = 1; signo < NSIG; signo++)
733 int target_signo = gdb_signal_from_host (signo);
734 if (target_signo < numsigs && pass_signals[target_signo])
735 sigaddset (&pass_mask, signo);
741 /* Prototypes for local functions. */
742 static int stop_wait_callback (struct lwp_info *lp, void *data);
743 static char *linux_child_pid_to_exec_file (struct target_ops *self, int pid);
744 static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
748 /* Destroy and free LP. */
751 lwp_free (struct lwp_info *lp)
753 xfree (lp->arch_private);
757 /* Remove all LWPs belong to PID from the lwp list. */
760 purge_lwp_list (int pid)
762 struct lwp_info *lp, *lpprev, *lpnext;
766 for (lp = lwp_list; lp; lp = lpnext)
770 if (ptid_get_pid (lp->ptid) == pid)
775 lpprev->next = lp->next;
784 /* Add the LWP specified by PTID to the list. PTID is the first LWP
785 in the process. Return a pointer to the structure describing the
788 This differs from add_lwp in that we don't let the arch specific
789 bits know about this new thread. Current clients of this callback
790 take the opportunity to install watchpoints in the new thread, and
791 we shouldn't do that for the first thread. If we're spawning a
792 child ("run"), the thread executes the shell wrapper first, and we
793 shouldn't touch it until it execs the program we want to debug.
794 For "attach", it'd be okay to call the callback, but it's not
795 necessary, because watchpoints can't yet have been inserted into
798 static struct lwp_info *
799 add_initial_lwp (ptid_t ptid)
803 gdb_assert (ptid_lwp_p (ptid));
805 lp = XNEW (struct lwp_info);
807 memset (lp, 0, sizeof (struct lwp_info));
809 lp->last_resume_kind = resume_continue;
810 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
821 /* Add the LWP specified by PID to the list. Return a pointer to the
822 structure describing the new LWP. The LWP should already be
825 static struct lwp_info *
826 add_lwp (ptid_t ptid)
830 lp = add_initial_lwp (ptid);
832 /* Let the arch specific bits know about this new thread. Current
833 clients of this callback take the opportunity to install
834 watchpoints in the new thread. We don't do this for the first
835 thread though. See add_initial_lwp. */
836 if (linux_nat_new_thread != NULL)
837 linux_nat_new_thread (lp);
842 /* Remove the LWP specified by PID from the list. */
845 delete_lwp (ptid_t ptid)
847 struct lwp_info *lp, *lpprev;
851 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
852 if (ptid_equal (lp->ptid, ptid))
859 lpprev->next = lp->next;
866 /* Return a pointer to the structure describing the LWP corresponding
867 to PID. If no corresponding LWP could be found, return NULL. */
869 static struct lwp_info *
870 find_lwp_pid (ptid_t ptid)
875 if (ptid_lwp_p (ptid))
876 lwp = ptid_get_lwp (ptid);
878 lwp = ptid_get_pid (ptid);
880 for (lp = lwp_list; lp; lp = lp->next)
881 if (lwp == ptid_get_lwp (lp->ptid))
887 /* See nat/linux-nat.h. */
890 iterate_over_lwps (ptid_t filter,
891 iterate_over_lwps_ftype callback,
894 struct lwp_info *lp, *lpnext;
896 for (lp = lwp_list; lp; lp = lpnext)
900 if (ptid_match (lp->ptid, filter))
902 if ((*callback) (lp, data) != 0)
910 /* Update our internal state when changing from one checkpoint to
911 another indicated by NEW_PTID. We can only switch single-threaded
912 applications, so we only create one new LWP, and the previous list
916 linux_nat_switch_fork (ptid_t new_ptid)
920 purge_lwp_list (ptid_get_pid (inferior_ptid));
922 lp = add_lwp (new_ptid);
925 /* This changes the thread's ptid while preserving the gdb thread
926 num. Also changes the inferior pid, while preserving the
928 thread_change_ptid (inferior_ptid, new_ptid);
930 /* We've just told GDB core that the thread changed target id, but,
931 in fact, it really is a different thread, with different register
933 registers_changed ();
936 /* Handle the exit of a single thread LP. */
939 exit_lwp (struct lwp_info *lp)
941 struct thread_info *th = find_thread_ptid (lp->ptid);
945 if (print_thread_events)
946 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
948 delete_thread (lp->ptid);
951 delete_lwp (lp->ptid);
954 /* Wait for the LWP specified by LP, which we have just attached to.
955 Returns a wait status for that LWP, to cache. */
958 linux_nat_post_attach_wait (ptid_t ptid, int first, int *signalled)
960 pid_t new_pid, pid = ptid_get_lwp (ptid);
963 if (linux_proc_pid_is_stopped (pid))
966 fprintf_unfiltered (gdb_stdlog,
967 "LNPAW: Attaching to a stopped process\n");
969 /* The process is definitely stopped. It is in a job control
970 stop, unless the kernel predates the TASK_STOPPED /
971 TASK_TRACED distinction, in which case it might be in a
972 ptrace stop. Make sure it is in a ptrace stop; from there we
973 can kill it, signal it, et cetera.
975 First make sure there is a pending SIGSTOP. Since we are
976 already attached, the process can not transition from stopped
977 to running without a PTRACE_CONT; so we know this signal will
978 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
979 probably already in the queue (unless this kernel is old
980 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
981 is not an RT signal, it can only be queued once. */
982 kill_lwp (pid, SIGSTOP);
984 /* Finally, resume the stopped process. This will deliver the SIGSTOP
985 (or a higher priority signal, just like normal PTRACE_ATTACH). */
986 ptrace (PTRACE_CONT, pid, 0, 0);
989 /* Make sure the initial process is stopped. The user-level threads
990 layer might want to poke around in the inferior, and that won't
991 work if things haven't stabilized yet. */
992 new_pid = my_waitpid (pid, &status, __WALL);
993 gdb_assert (pid == new_pid);
995 if (!WIFSTOPPED (status))
997 /* The pid we tried to attach has apparently just exited. */
999 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1000 pid, status_to_str (status));
1004 if (WSTOPSIG (status) != SIGSTOP)
1007 if (debug_linux_nat)
1008 fprintf_unfiltered (gdb_stdlog,
1009 "LNPAW: Received %s after attaching\n",
1010 status_to_str (status));
1017 linux_nat_create_inferior (struct target_ops *ops,
1018 char *exec_file, char *allargs, char **env,
1021 struct cleanup *restore_personality
1022 = maybe_disable_address_space_randomization (disable_randomization);
1024 /* The fork_child mechanism is synchronous and calls target_wait, so
1025 we have to mask the async mode. */
1027 /* Make sure we report all signals during startup. */
1028 linux_nat_pass_signals (ops, 0, NULL);
1030 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1032 do_cleanups (restore_personality);
1035 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1036 already attached. Returns true if a new LWP is found, false
1040 attach_proc_task_lwp_callback (ptid_t ptid)
1042 struct lwp_info *lp;
1044 /* Ignore LWPs we're already attached to. */
1045 lp = find_lwp_pid (ptid);
1048 int lwpid = ptid_get_lwp (ptid);
1050 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1054 /* Be quiet if we simply raced with the thread exiting.
1055 EPERM is returned if the thread's task still exists, and
1056 is marked as exited or zombie, as well as other
1057 conditions, so in that case, confirm the status in
1058 /proc/PID/status. */
1060 || (err == EPERM && linux_proc_pid_is_gone (lwpid)))
1062 if (debug_linux_nat)
1064 fprintf_unfiltered (gdb_stdlog,
1065 "Cannot attach to lwp %d: "
1066 "thread is gone (%d: %s)\n",
1067 lwpid, err, safe_strerror (err));
1072 warning (_("Cannot attach to lwp %d: %s"),
1074 linux_ptrace_attach_fail_reason_string (ptid,
1080 if (debug_linux_nat)
1081 fprintf_unfiltered (gdb_stdlog,
1082 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1083 target_pid_to_str (ptid));
1085 lp = add_lwp (ptid);
1087 /* The next time we wait for this LWP we'll see a SIGSTOP as
1088 PTRACE_ATTACH brings it to a halt. */
1091 /* We need to wait for a stop before being able to make the
1092 next ptrace call on this LWP. */
1093 lp->must_set_ptrace_flags = 1;
1102 linux_nat_attach (struct target_ops *ops, const char *args, int from_tty)
1104 struct lwp_info *lp;
1108 /* Make sure we report all signals during attach. */
1109 linux_nat_pass_signals (ops, 0, NULL);
1113 linux_ops->to_attach (ops, args, from_tty);
1115 CATCH (ex, RETURN_MASK_ERROR)
1117 pid_t pid = parse_pid_to_attach (args);
1118 struct buffer buffer;
1119 char *message, *buffer_s;
1121 message = xstrdup (ex.message);
1122 make_cleanup (xfree, message);
1124 buffer_init (&buffer);
1125 linux_ptrace_attach_fail_reason (pid, &buffer);
1127 buffer_grow_str0 (&buffer, "");
1128 buffer_s = buffer_finish (&buffer);
1129 make_cleanup (xfree, buffer_s);
1131 if (*buffer_s != '\0')
1132 throw_error (ex.error, "warning: %s\n%s", buffer_s, message);
1134 throw_error (ex.error, "%s", message);
1138 /* The ptrace base target adds the main thread with (pid,0,0)
1139 format. Decorate it with lwp info. */
1140 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1141 ptid_get_pid (inferior_ptid),
1143 thread_change_ptid (inferior_ptid, ptid);
1145 /* Add the initial process as the first LWP to the list. */
1146 lp = add_initial_lwp (ptid);
1148 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->signalled);
1149 if (!WIFSTOPPED (status))
1151 if (WIFEXITED (status))
1153 int exit_code = WEXITSTATUS (status);
1155 target_terminal_ours ();
1156 target_mourn_inferior ();
1158 error (_("Unable to attach: program exited normally."));
1160 error (_("Unable to attach: program exited with code %d."),
1163 else if (WIFSIGNALED (status))
1165 enum gdb_signal signo;
1167 target_terminal_ours ();
1168 target_mourn_inferior ();
1170 signo = gdb_signal_from_host (WTERMSIG (status));
1171 error (_("Unable to attach: program terminated with signal "
1173 gdb_signal_to_name (signo),
1174 gdb_signal_to_string (signo));
1177 internal_error (__FILE__, __LINE__,
1178 _("unexpected status %d for PID %ld"),
1179 status, (long) ptid_get_lwp (ptid));
1184 /* Save the wait status to report later. */
1186 if (debug_linux_nat)
1187 fprintf_unfiltered (gdb_stdlog,
1188 "LNA: waitpid %ld, saving status %s\n",
1189 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1191 lp->status = status;
1193 /* We must attach to every LWP. If /proc is mounted, use that to
1194 find them now. The inferior may be using raw clone instead of
1195 using pthreads. But even if it is using pthreads, thread_db
1196 walks structures in the inferior's address space to find the list
1197 of threads/LWPs, and those structures may well be corrupted.
1198 Note that once thread_db is loaded, we'll still use it to list
1199 threads and associate pthread info with each LWP. */
1200 linux_proc_attach_tgid_threads (ptid_get_pid (lp->ptid),
1201 attach_proc_task_lwp_callback);
1203 if (target_can_async_p ())
1207 /* Get pending status of LP. */
1209 get_pending_status (struct lwp_info *lp, int *status)
1211 enum gdb_signal signo = GDB_SIGNAL_0;
1213 /* If we paused threads momentarily, we may have stored pending
1214 events in lp->status or lp->waitstatus (see stop_wait_callback),
1215 and GDB core hasn't seen any signal for those threads.
1216 Otherwise, the last signal reported to the core is found in the
1217 thread object's stop_signal.
1219 There's a corner case that isn't handled here at present. Only
1220 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1221 stop_signal make sense as a real signal to pass to the inferior.
1222 Some catchpoint related events, like
1223 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1224 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1225 those traps are debug API (ptrace in our case) related and
1226 induced; the inferior wouldn't see them if it wasn't being
1227 traced. Hence, we should never pass them to the inferior, even
1228 when set to pass state. Since this corner case isn't handled by
1229 infrun.c when proceeding with a signal, for consistency, neither
1230 do we handle it here (or elsewhere in the file we check for
1231 signal pass state). Normally SIGTRAP isn't set to pass state, so
1232 this is really a corner case. */
1234 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1235 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1236 else if (lp->status)
1237 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1238 else if (target_is_non_stop_p () && !is_executing (lp->ptid))
1240 struct thread_info *tp = find_thread_ptid (lp->ptid);
1242 signo = tp->suspend.stop_signal;
1244 else if (!target_is_non_stop_p ())
1246 struct target_waitstatus last;
1249 get_last_target_status (&last_ptid, &last);
1251 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1253 struct thread_info *tp = find_thread_ptid (lp->ptid);
1255 signo = tp->suspend.stop_signal;
1261 if (signo == GDB_SIGNAL_0)
1263 if (debug_linux_nat)
1264 fprintf_unfiltered (gdb_stdlog,
1265 "GPT: lwp %s has no pending signal\n",
1266 target_pid_to_str (lp->ptid));
1268 else if (!signal_pass_state (signo))
1270 if (debug_linux_nat)
1271 fprintf_unfiltered (gdb_stdlog,
1272 "GPT: lwp %s had signal %s, "
1273 "but it is in no pass state\n",
1274 target_pid_to_str (lp->ptid),
1275 gdb_signal_to_string (signo));
1279 *status = W_STOPCODE (gdb_signal_to_host (signo));
1281 if (debug_linux_nat)
1282 fprintf_unfiltered (gdb_stdlog,
1283 "GPT: lwp %s has pending signal %s\n",
1284 target_pid_to_str (lp->ptid),
1285 gdb_signal_to_string (signo));
1292 detach_callback (struct lwp_info *lp, void *data)
1294 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1296 if (debug_linux_nat && lp->status)
1297 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1298 strsignal (WSTOPSIG (lp->status)),
1299 target_pid_to_str (lp->ptid));
1301 /* If there is a pending SIGSTOP, get rid of it. */
1304 if (debug_linux_nat)
1305 fprintf_unfiltered (gdb_stdlog,
1306 "DC: Sending SIGCONT to %s\n",
1307 target_pid_to_str (lp->ptid));
1309 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1313 /* We don't actually detach from the LWP that has an id equal to the
1314 overall process id just yet. */
1315 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1319 /* Pass on any pending signal for this LWP. */
1320 get_pending_status (lp, &status);
1322 if (linux_nat_prepare_to_resume != NULL)
1323 linux_nat_prepare_to_resume (lp);
1325 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1326 WSTOPSIG (status)) < 0)
1327 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1328 safe_strerror (errno));
1330 if (debug_linux_nat)
1331 fprintf_unfiltered (gdb_stdlog,
1332 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1333 target_pid_to_str (lp->ptid),
1334 strsignal (WSTOPSIG (status)));
1336 delete_lwp (lp->ptid);
1343 linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
1347 struct lwp_info *main_lwp;
1349 pid = ptid_get_pid (inferior_ptid);
1351 /* Don't unregister from the event loop, as there may be other
1352 inferiors running. */
1354 /* Stop all threads before detaching. ptrace requires that the
1355 thread is stopped to sucessfully detach. */
1356 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1357 /* ... and wait until all of them have reported back that
1358 they're no longer running. */
1359 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1361 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1363 /* Only the initial process should be left right now. */
1364 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1366 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1368 /* Pass on any pending signal for the last LWP. */
1369 if ((args == NULL || *args == '\0')
1370 && get_pending_status (main_lwp, &status) != -1
1371 && WIFSTOPPED (status))
1375 /* Put the signal number in ARGS so that inf_ptrace_detach will
1376 pass it along with PTRACE_DETACH. */
1377 tem = (char *) alloca (8);
1378 xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
1380 if (debug_linux_nat)
1381 fprintf_unfiltered (gdb_stdlog,
1382 "LND: Sending signal %s to %s\n",
1384 target_pid_to_str (main_lwp->ptid));
1387 if (linux_nat_prepare_to_resume != NULL)
1388 linux_nat_prepare_to_resume (main_lwp);
1389 delete_lwp (main_lwp->ptid);
1391 if (forks_exist_p ())
1393 /* Multi-fork case. The current inferior_ptid is being detached
1394 from, but there are other viable forks to debug. Detach from
1395 the current fork, and context-switch to the first
1397 linux_fork_detach (args, from_tty);
1400 linux_ops->to_detach (ops, args, from_tty);
1403 /* Resume execution of the inferior process. If STEP is nonzero,
1404 single-step it. If SIGNAL is nonzero, give it that signal. */
1407 linux_resume_one_lwp_throw (struct lwp_info *lp, int step,
1408 enum gdb_signal signo)
1412 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1413 We only presently need that if the LWP is stepped though (to
1414 handle the case of stepping a breakpoint instruction). */
1417 struct regcache *regcache = get_thread_regcache (lp->ptid);
1419 lp->stop_pc = regcache_read_pc (regcache);
1424 if (linux_nat_prepare_to_resume != NULL)
1425 linux_nat_prepare_to_resume (lp);
1426 linux_ops->to_resume (linux_ops, lp->ptid, step, signo);
1428 /* Successfully resumed. Clear state that no longer makes sense,
1429 and mark the LWP as running. Must not do this before resuming
1430 otherwise if that fails other code will be confused. E.g., we'd
1431 later try to stop the LWP and hang forever waiting for a stop
1432 status. Note that we must not throw after this is cleared,
1433 otherwise handle_zombie_lwp_error would get confused. */
1436 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1437 registers_changed_ptid (lp->ptid);
1440 /* Called when we try to resume a stopped LWP and that errors out. If
1441 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1442 or about to become), discard the error, clear any pending status
1443 the LWP may have, and return true (we'll collect the exit status
1444 soon enough). Otherwise, return false. */
1447 check_ptrace_stopped_lwp_gone (struct lwp_info *lp)
1449 /* If we get an error after resuming the LWP successfully, we'd
1450 confuse !T state for the LWP being gone. */
1451 gdb_assert (lp->stopped);
1453 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1454 because even if ptrace failed with ESRCH, the tracee may be "not
1455 yet fully dead", but already refusing ptrace requests. In that
1456 case the tracee has 'R (Running)' state for a little bit
1457 (observed in Linux 3.18). See also the note on ESRCH in the
1458 ptrace(2) man page. Instead, check whether the LWP has any state
1459 other than ptrace-stopped. */
1461 /* Don't assume anything if /proc/PID/status can't be read. */
1462 if (linux_proc_pid_is_trace_stopped_nowarn (ptid_get_lwp (lp->ptid)) == 0)
1464 lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
1466 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
1472 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1473 disappears while we try to resume it. */
1476 linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1480 linux_resume_one_lwp_throw (lp, step, signo);
1482 CATCH (ex, RETURN_MASK_ERROR)
1484 if (!check_ptrace_stopped_lwp_gone (lp))
1485 throw_exception (ex);
1493 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1497 struct inferior *inf = find_inferior_ptid (lp->ptid);
1499 if (inf->vfork_child != NULL)
1501 if (debug_linux_nat)
1502 fprintf_unfiltered (gdb_stdlog,
1503 "RC: Not resuming %s (vfork parent)\n",
1504 target_pid_to_str (lp->ptid));
1506 else if (!lwp_status_pending_p (lp))
1508 if (debug_linux_nat)
1509 fprintf_unfiltered (gdb_stdlog,
1510 "RC: Resuming sibling %s, %s, %s\n",
1511 target_pid_to_str (lp->ptid),
1512 (signo != GDB_SIGNAL_0
1513 ? strsignal (gdb_signal_to_host (signo))
1515 step ? "step" : "resume");
1517 linux_resume_one_lwp (lp, step, signo);
1521 if (debug_linux_nat)
1522 fprintf_unfiltered (gdb_stdlog,
1523 "RC: Not resuming sibling %s (has pending)\n",
1524 target_pid_to_str (lp->ptid));
1529 if (debug_linux_nat)
1530 fprintf_unfiltered (gdb_stdlog,
1531 "RC: Not resuming sibling %s (not stopped)\n",
1532 target_pid_to_str (lp->ptid));
1536 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1537 Resume LWP with the last stop signal, if it is in pass state. */
1540 linux_nat_resume_callback (struct lwp_info *lp, void *except)
1542 enum gdb_signal signo = GDB_SIGNAL_0;
1549 struct thread_info *thread;
1551 thread = find_thread_ptid (lp->ptid);
1554 signo = thread->suspend.stop_signal;
1555 thread->suspend.stop_signal = GDB_SIGNAL_0;
1559 resume_lwp (lp, 0, signo);
1564 resume_clear_callback (struct lwp_info *lp, void *data)
1567 lp->last_resume_kind = resume_stop;
1572 resume_set_callback (struct lwp_info *lp, void *data)
1575 lp->last_resume_kind = resume_continue;
1580 linux_nat_resume (struct target_ops *ops,
1581 ptid_t ptid, int step, enum gdb_signal signo)
1583 struct lwp_info *lp;
1586 if (debug_linux_nat)
1587 fprintf_unfiltered (gdb_stdlog,
1588 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1589 step ? "step" : "resume",
1590 target_pid_to_str (ptid),
1591 (signo != GDB_SIGNAL_0
1592 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1593 target_pid_to_str (inferior_ptid));
1595 /* A specific PTID means `step only this process id'. */
1596 resume_many = (ptid_equal (minus_one_ptid, ptid)
1597 || ptid_is_pid (ptid));
1599 /* Mark the lwps we're resuming as resumed. */
1600 iterate_over_lwps (ptid, resume_set_callback, NULL);
1602 /* See if it's the current inferior that should be handled
1605 lp = find_lwp_pid (inferior_ptid);
1607 lp = find_lwp_pid (ptid);
1608 gdb_assert (lp != NULL);
1610 /* Remember if we're stepping. */
1611 lp->last_resume_kind = step ? resume_step : resume_continue;
1613 /* If we have a pending wait status for this thread, there is no
1614 point in resuming the process. But first make sure that
1615 linux_nat_wait won't preemptively handle the event - we
1616 should never take this short-circuit if we are going to
1617 leave LP running, since we have skipped resuming all the
1618 other threads. This bit of code needs to be synchronized
1619 with linux_nat_wait. */
1621 if (lp->status && WIFSTOPPED (lp->status))
1624 && WSTOPSIG (lp->status)
1625 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1627 if (debug_linux_nat)
1628 fprintf_unfiltered (gdb_stdlog,
1629 "LLR: Not short circuiting for ignored "
1630 "status 0x%x\n", lp->status);
1632 /* FIXME: What should we do if we are supposed to continue
1633 this thread with a signal? */
1634 gdb_assert (signo == GDB_SIGNAL_0);
1635 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1640 if (lwp_status_pending_p (lp))
1642 /* FIXME: What should we do if we are supposed to continue
1643 this thread with a signal? */
1644 gdb_assert (signo == GDB_SIGNAL_0);
1646 if (debug_linux_nat)
1647 fprintf_unfiltered (gdb_stdlog,
1648 "LLR: Short circuiting for status 0x%x\n",
1651 if (target_can_async_p ())
1654 /* Tell the event loop we have something to process. */
1661 iterate_over_lwps (ptid, linux_nat_resume_callback, lp);
1663 if (debug_linux_nat)
1664 fprintf_unfiltered (gdb_stdlog,
1665 "LLR: %s %s, %s (resume event thread)\n",
1666 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1667 target_pid_to_str (lp->ptid),
1668 (signo != GDB_SIGNAL_0
1669 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1671 linux_resume_one_lwp (lp, step, signo);
1673 if (target_can_async_p ())
1677 /* Send a signal to an LWP. */
1680 kill_lwp (int lwpid, int signo)
1685 ret = syscall (__NR_tkill, lwpid, signo);
1686 if (errno == ENOSYS)
1688 /* If tkill fails, then we are not using nptl threads, a
1689 configuration we no longer support. */
1690 perror_with_name (("tkill"));
1695 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1696 event, check if the core is interested in it: if not, ignore the
1697 event, and keep waiting; otherwise, we need to toggle the LWP's
1698 syscall entry/exit status, since the ptrace event itself doesn't
1699 indicate it, and report the trap to higher layers. */
1702 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1704 struct target_waitstatus *ourstatus = &lp->waitstatus;
1705 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1706 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1710 /* If we're stopping threads, there's a SIGSTOP pending, which
1711 makes it so that the LWP reports an immediate syscall return,
1712 followed by the SIGSTOP. Skip seeing that "return" using
1713 PTRACE_CONT directly, and let stop_wait_callback collect the
1714 SIGSTOP. Later when the thread is resumed, a new syscall
1715 entry event. If we didn't do this (and returned 0), we'd
1716 leave a syscall entry pending, and our caller, by using
1717 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1718 itself. Later, when the user re-resumes this LWP, we'd see
1719 another syscall entry event and we'd mistake it for a return.
1721 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1722 (leaving immediately with LWP->signalled set, without issuing
1723 a PTRACE_CONT), it would still be problematic to leave this
1724 syscall enter pending, as later when the thread is resumed,
1725 it would then see the same syscall exit mentioned above,
1726 followed by the delayed SIGSTOP, while the syscall didn't
1727 actually get to execute. It seems it would be even more
1728 confusing to the user. */
1730 if (debug_linux_nat)
1731 fprintf_unfiltered (gdb_stdlog,
1732 "LHST: ignoring syscall %d "
1733 "for LWP %ld (stopping threads), "
1734 "resuming with PTRACE_CONT for SIGSTOP\n",
1736 ptid_get_lwp (lp->ptid));
1738 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1739 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1744 /* Always update the entry/return state, even if this particular
1745 syscall isn't interesting to the core now. In async mode,
1746 the user could install a new catchpoint for this syscall
1747 between syscall enter/return, and we'll need to know to
1748 report a syscall return if that happens. */
1749 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1750 ? TARGET_WAITKIND_SYSCALL_RETURN
1751 : TARGET_WAITKIND_SYSCALL_ENTRY);
1753 if (catch_syscall_enabled ())
1755 if (catching_syscall_number (syscall_number))
1757 /* Alright, an event to report. */
1758 ourstatus->kind = lp->syscall_state;
1759 ourstatus->value.syscall_number = syscall_number;
1761 if (debug_linux_nat)
1762 fprintf_unfiltered (gdb_stdlog,
1763 "LHST: stopping for %s of syscall %d"
1766 == TARGET_WAITKIND_SYSCALL_ENTRY
1767 ? "entry" : "return",
1769 ptid_get_lwp (lp->ptid));
1773 if (debug_linux_nat)
1774 fprintf_unfiltered (gdb_stdlog,
1775 "LHST: ignoring %s of syscall %d "
1777 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1778 ? "entry" : "return",
1780 ptid_get_lwp (lp->ptid));
1784 /* If we had been syscall tracing, and hence used PT_SYSCALL
1785 before on this LWP, it could happen that the user removes all
1786 syscall catchpoints before we get to process this event.
1787 There are two noteworthy issues here:
1789 - When stopped at a syscall entry event, resuming with
1790 PT_STEP still resumes executing the syscall and reports a
1793 - Only PT_SYSCALL catches syscall enters. If we last
1794 single-stepped this thread, then this event can't be a
1795 syscall enter. If we last single-stepped this thread, this
1796 has to be a syscall exit.
1798 The points above mean that the next resume, be it PT_STEP or
1799 PT_CONTINUE, can not trigger a syscall trace event. */
1800 if (debug_linux_nat)
1801 fprintf_unfiltered (gdb_stdlog,
1802 "LHST: caught syscall event "
1803 "with no syscall catchpoints."
1804 " %d for LWP %ld, ignoring\n",
1806 ptid_get_lwp (lp->ptid));
1807 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1810 /* The core isn't interested in this event. For efficiency, avoid
1811 stopping all threads only to have the core resume them all again.
1812 Since we're not stopping threads, if we're still syscall tracing
1813 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1814 subsequent syscall. Simply resume using the inf-ptrace layer,
1815 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1817 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
1821 /* Handle a GNU/Linux extended wait response. If we see a clone
1822 event, we need to add the new LWP to our list (and not report the
1823 trap to higher layers). This function returns non-zero if the
1824 event should be ignored and we should wait again. If STOPPING is
1825 true, the new LWP remains stopped, otherwise it is continued. */
1828 linux_handle_extended_wait (struct lwp_info *lp, int status)
1830 int pid = ptid_get_lwp (lp->ptid);
1831 struct target_waitstatus *ourstatus = &lp->waitstatus;
1832 int event = linux_ptrace_get_extended_event (status);
1834 /* All extended events we currently use are mid-syscall. Only
1835 PTRACE_EVENT_STOP is delivered more like a signal-stop, but
1836 you have to be using PTRACE_SEIZE to get that. */
1837 lp->syscall_state = TARGET_WAITKIND_SYSCALL_ENTRY;
1839 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1840 || event == PTRACE_EVENT_CLONE)
1842 unsigned long new_pid;
1845 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
1847 /* If we haven't already seen the new PID stop, wait for it now. */
1848 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
1850 /* The new child has a pending SIGSTOP. We can't affect it until it
1851 hits the SIGSTOP, but we're already attached. */
1852 ret = my_waitpid (new_pid, &status, __WALL);
1854 perror_with_name (_("waiting for new child"));
1855 else if (ret != new_pid)
1856 internal_error (__FILE__, __LINE__,
1857 _("wait returned unexpected PID %d"), ret);
1858 else if (!WIFSTOPPED (status))
1859 internal_error (__FILE__, __LINE__,
1860 _("wait returned unexpected status 0x%x"), status);
1863 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
1865 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
1867 /* The arch-specific native code may need to know about new
1868 forks even if those end up never mapped to an
1870 if (linux_nat_new_fork != NULL)
1871 linux_nat_new_fork (lp, new_pid);
1874 if (event == PTRACE_EVENT_FORK
1875 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
1877 /* Handle checkpointing by linux-fork.c here as a special
1878 case. We don't want the follow-fork-mode or 'catch fork'
1879 to interfere with this. */
1881 /* This won't actually modify the breakpoint list, but will
1882 physically remove the breakpoints from the child. */
1883 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
1885 /* Retain child fork in ptrace (stopped) state. */
1886 if (!find_fork_pid (new_pid))
1889 /* Report as spurious, so that infrun doesn't want to follow
1890 this fork. We're actually doing an infcall in
1892 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
1894 /* Report the stop to the core. */
1898 if (event == PTRACE_EVENT_FORK)
1899 ourstatus->kind = TARGET_WAITKIND_FORKED;
1900 else if (event == PTRACE_EVENT_VFORK)
1901 ourstatus->kind = TARGET_WAITKIND_VFORKED;
1902 else if (event == PTRACE_EVENT_CLONE)
1904 struct lwp_info *new_lp;
1906 ourstatus->kind = TARGET_WAITKIND_IGNORE;
1908 if (debug_linux_nat)
1909 fprintf_unfiltered (gdb_stdlog,
1910 "LHEW: Got clone event "
1911 "from LWP %d, new child is LWP %ld\n",
1914 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
1915 new_lp->stopped = 1;
1916 new_lp->resumed = 1;
1918 /* If the thread_db layer is active, let it record the user
1919 level thread id and status, and add the thread to GDB's
1921 if (!thread_db_notice_clone (lp->ptid, new_lp->ptid))
1923 /* The process is not using thread_db. Add the LWP to
1925 target_post_attach (ptid_get_lwp (new_lp->ptid));
1926 add_thread (new_lp->ptid);
1929 /* Even if we're stopping the thread for some reason
1930 internal to this module, from the perspective of infrun
1931 and the user/frontend, this new thread is running until
1932 it next reports a stop. */
1933 set_running (new_lp->ptid, 1);
1934 set_executing (new_lp->ptid, 1);
1936 if (WSTOPSIG (status) != SIGSTOP)
1938 /* This can happen if someone starts sending signals to
1939 the new thread before it gets a chance to run, which
1940 have a lower number than SIGSTOP (e.g. SIGUSR1).
1941 This is an unlikely case, and harder to handle for
1942 fork / vfork than for clone, so we do not try - but
1943 we handle it for clone events here. */
1945 new_lp->signalled = 1;
1947 /* We created NEW_LP so it cannot yet contain STATUS. */
1948 gdb_assert (new_lp->status == 0);
1950 /* Save the wait status to report later. */
1951 if (debug_linux_nat)
1952 fprintf_unfiltered (gdb_stdlog,
1953 "LHEW: waitpid of new LWP %ld, "
1954 "saving status %s\n",
1955 (long) ptid_get_lwp (new_lp->ptid),
1956 status_to_str (status));
1957 new_lp->status = status;
1959 else if (report_thread_events)
1961 new_lp->waitstatus.kind = TARGET_WAITKIND_THREAD_CREATED;
1962 new_lp->status = status;
1971 if (event == PTRACE_EVENT_EXEC)
1973 if (debug_linux_nat)
1974 fprintf_unfiltered (gdb_stdlog,
1975 "LHEW: Got exec event from LWP %ld\n",
1976 ptid_get_lwp (lp->ptid));
1978 ourstatus->kind = TARGET_WAITKIND_EXECD;
1979 ourstatus->value.execd_pathname
1980 = xstrdup (linux_child_pid_to_exec_file (NULL, pid));
1982 /* The thread that execed must have been resumed, but, when a
1983 thread execs, it changes its tid to the tgid, and the old
1984 tgid thread might have not been resumed. */
1989 if (event == PTRACE_EVENT_VFORK_DONE)
1991 if (current_inferior ()->waiting_for_vfork_done)
1993 if (debug_linux_nat)
1994 fprintf_unfiltered (gdb_stdlog,
1995 "LHEW: Got expected PTRACE_EVENT_"
1996 "VFORK_DONE from LWP %ld: stopping\n",
1997 ptid_get_lwp (lp->ptid));
1999 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2003 if (debug_linux_nat)
2004 fprintf_unfiltered (gdb_stdlog,
2005 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2006 "from LWP %ld: ignoring\n",
2007 ptid_get_lwp (lp->ptid));
2011 internal_error (__FILE__, __LINE__,
2012 _("unknown ptrace event %d"), event);
2015 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2019 wait_lwp (struct lwp_info *lp)
2023 int thread_dead = 0;
2026 gdb_assert (!lp->stopped);
2027 gdb_assert (lp->status == 0);
2029 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2030 block_child_signals (&prev_mask);
2034 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WALL | WNOHANG);
2035 if (pid == -1 && errno == ECHILD)
2037 /* The thread has previously exited. We need to delete it
2038 now because if this was a non-leader thread execing, we
2039 won't get an exit event. See comments on exec events at
2040 the top of the file. */
2042 if (debug_linux_nat)
2043 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2044 target_pid_to_str (lp->ptid));
2049 /* Bugs 10970, 12702.
2050 Thread group leader may have exited in which case we'll lock up in
2051 waitpid if there are other threads, even if they are all zombies too.
2052 Basically, we're not supposed to use waitpid this way.
2053 tkill(pid,0) cannot be used here as it gets ESRCH for both
2054 for zombie and running processes.
2056 As a workaround, check if we're waiting for the thread group leader and
2057 if it's a zombie, and avoid calling waitpid if it is.
2059 This is racy, what if the tgl becomes a zombie right after we check?
2060 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2061 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2063 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2064 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2067 if (debug_linux_nat)
2068 fprintf_unfiltered (gdb_stdlog,
2069 "WL: Thread group leader %s vanished.\n",
2070 target_pid_to_str (lp->ptid));
2074 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2075 get invoked despite our caller had them intentionally blocked by
2076 block_child_signals. This is sensitive only to the loop of
2077 linux_nat_wait_1 and there if we get called my_waitpid gets called
2078 again before it gets to sigsuspend so we can safely let the handlers
2079 get executed here. */
2081 if (debug_linux_nat)
2082 fprintf_unfiltered (gdb_stdlog, "WL: about to sigsuspend\n");
2083 sigsuspend (&suspend_mask);
2086 restore_child_signals_mask (&prev_mask);
2090 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2092 if (debug_linux_nat)
2094 fprintf_unfiltered (gdb_stdlog,
2095 "WL: waitpid %s received %s\n",
2096 target_pid_to_str (lp->ptid),
2097 status_to_str (status));
2100 /* Check if the thread has exited. */
2101 if (WIFEXITED (status) || WIFSIGNALED (status))
2103 if (report_thread_events
2104 || ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
2106 if (debug_linux_nat)
2107 fprintf_unfiltered (gdb_stdlog, "WL: LWP %d exited.\n",
2108 ptid_get_pid (lp->ptid));
2110 /* If this is the leader exiting, it means the whole
2111 process is gone. Store the status to report to the
2112 core. Store it in lp->waitstatus, because lp->status
2113 would be ambiguous (W_EXITCODE(0,0) == 0). */
2114 store_waitstatus (&lp->waitstatus, status);
2119 if (debug_linux_nat)
2120 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2121 target_pid_to_str (lp->ptid));
2131 gdb_assert (WIFSTOPPED (status));
2134 if (lp->must_set_ptrace_flags)
2136 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2137 int options = linux_nat_ptrace_options (inf->attach_flag);
2139 linux_enable_event_reporting (ptid_get_lwp (lp->ptid), options);
2140 lp->must_set_ptrace_flags = 0;
2143 /* Handle GNU/Linux's syscall SIGTRAPs. */
2144 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2146 /* No longer need the sysgood bit. The ptrace event ends up
2147 recorded in lp->waitstatus if we care for it. We can carry
2148 on handling the event like a regular SIGTRAP from here
2150 status = W_STOPCODE (SIGTRAP);
2151 if (linux_handle_syscall_trap (lp, 1))
2152 return wait_lwp (lp);
2156 /* Almost all other ptrace-stops are known to be outside of system
2157 calls, with further exceptions in linux_handle_extended_wait. */
2158 lp->syscall_state = TARGET_WAITKIND_IGNORE;
2161 /* Handle GNU/Linux's extended waitstatus for trace events. */
2162 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
2163 && linux_is_extended_waitstatus (status))
2165 if (debug_linux_nat)
2166 fprintf_unfiltered (gdb_stdlog,
2167 "WL: Handling extended status 0x%06x\n",
2169 linux_handle_extended_wait (lp, status);
2176 /* Send a SIGSTOP to LP. */
2179 stop_callback (struct lwp_info *lp, void *data)
2181 if (!lp->stopped && !lp->signalled)
2185 if (debug_linux_nat)
2187 fprintf_unfiltered (gdb_stdlog,
2188 "SC: kill %s **<SIGSTOP>**\n",
2189 target_pid_to_str (lp->ptid));
2192 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2193 if (debug_linux_nat)
2195 fprintf_unfiltered (gdb_stdlog,
2196 "SC: lwp kill %d %s\n",
2198 errno ? safe_strerror (errno) : "ERRNO-OK");
2202 gdb_assert (lp->status == 0);
2208 /* Request a stop on LWP. */
2211 linux_stop_lwp (struct lwp_info *lwp)
2213 stop_callback (lwp, NULL);
2216 /* See linux-nat.h */
2219 linux_stop_and_wait_all_lwps (void)
2221 /* Stop all LWP's ... */
2222 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
2224 /* ... and wait until all of them have reported back that
2225 they're no longer running. */
2226 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
2229 /* See linux-nat.h */
2232 linux_unstop_all_lwps (void)
2234 iterate_over_lwps (minus_one_ptid,
2235 resume_stopped_resumed_lwps, &minus_one_ptid);
2238 /* Return non-zero if LWP PID has a pending SIGINT. */
2241 linux_nat_has_pending_sigint (int pid)
2243 sigset_t pending, blocked, ignored;
2245 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2247 if (sigismember (&pending, SIGINT)
2248 && !sigismember (&ignored, SIGINT))
2254 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2257 set_ignore_sigint (struct lwp_info *lp, void *data)
2259 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2260 flag to consume the next one. */
2261 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2262 && WSTOPSIG (lp->status) == SIGINT)
2265 lp->ignore_sigint = 1;
2270 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2271 This function is called after we know the LWP has stopped; if the LWP
2272 stopped before the expected SIGINT was delivered, then it will never have
2273 arrived. Also, if the signal was delivered to a shared queue and consumed
2274 by a different thread, it will never be delivered to this LWP. */
2277 maybe_clear_ignore_sigint (struct lwp_info *lp)
2279 if (!lp->ignore_sigint)
2282 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2284 if (debug_linux_nat)
2285 fprintf_unfiltered (gdb_stdlog,
2286 "MCIS: Clearing bogus flag for %s\n",
2287 target_pid_to_str (lp->ptid));
2288 lp->ignore_sigint = 0;
2292 /* Fetch the possible triggered data watchpoint info and store it in
2295 On some archs, like x86, that use debug registers to set
2296 watchpoints, it's possible that the way to know which watched
2297 address trapped, is to check the register that is used to select
2298 which address to watch. Problem is, between setting the watchpoint
2299 and reading back which data address trapped, the user may change
2300 the set of watchpoints, and, as a consequence, GDB changes the
2301 debug registers in the inferior. To avoid reading back a stale
2302 stopped-data-address when that happens, we cache in LP the fact
2303 that a watchpoint trapped, and the corresponding data address, as
2304 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2305 registers meanwhile, we have the cached data we can rely on. */
2308 check_stopped_by_watchpoint (struct lwp_info *lp)
2310 struct cleanup *old_chain;
2312 if (linux_ops->to_stopped_by_watchpoint == NULL)
2315 old_chain = save_inferior_ptid ();
2316 inferior_ptid = lp->ptid;
2318 if (linux_ops->to_stopped_by_watchpoint (linux_ops))
2320 lp->stop_reason = TARGET_STOPPED_BY_WATCHPOINT;
2322 if (linux_ops->to_stopped_data_address != NULL)
2323 lp->stopped_data_address_p =
2324 linux_ops->to_stopped_data_address (¤t_target,
2325 &lp->stopped_data_address);
2327 lp->stopped_data_address_p = 0;
2330 do_cleanups (old_chain);
2332 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2335 /* Returns true if the LWP had stopped for a watchpoint. */
2338 linux_nat_stopped_by_watchpoint (struct target_ops *ops)
2340 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2342 gdb_assert (lp != NULL);
2344 return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
2348 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2350 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2352 gdb_assert (lp != NULL);
2354 *addr_p = lp->stopped_data_address;
2356 return lp->stopped_data_address_p;
2359 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2362 sigtrap_is_event (int status)
2364 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2367 /* Set alternative SIGTRAP-like events recognizer. If
2368 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2372 linux_nat_set_status_is_event (struct target_ops *t,
2373 int (*status_is_event) (int status))
2375 linux_nat_status_is_event = status_is_event;
2378 /* Wait until LP is stopped. */
2381 stop_wait_callback (struct lwp_info *lp, void *data)
2383 struct inferior *inf = find_inferior_ptid (lp->ptid);
2385 /* If this is a vfork parent, bail out, it is not going to report
2386 any SIGSTOP until the vfork is done with. */
2387 if (inf->vfork_child != NULL)
2394 status = wait_lwp (lp);
2398 if (lp->ignore_sigint && WIFSTOPPED (status)
2399 && WSTOPSIG (status) == SIGINT)
2401 lp->ignore_sigint = 0;
2404 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2406 if (debug_linux_nat)
2407 fprintf_unfiltered (gdb_stdlog,
2408 "PTRACE_CONT %s, 0, 0 (%s) "
2409 "(discarding SIGINT)\n",
2410 target_pid_to_str (lp->ptid),
2411 errno ? safe_strerror (errno) : "OK");
2413 return stop_wait_callback (lp, NULL);
2416 maybe_clear_ignore_sigint (lp);
2418 if (WSTOPSIG (status) != SIGSTOP)
2420 /* The thread was stopped with a signal other than SIGSTOP. */
2422 if (debug_linux_nat)
2423 fprintf_unfiltered (gdb_stdlog,
2424 "SWC: Pending event %s in %s\n",
2425 status_to_str ((int) status),
2426 target_pid_to_str (lp->ptid));
2428 /* Save the sigtrap event. */
2429 lp->status = status;
2430 gdb_assert (lp->signalled);
2431 save_stop_reason (lp);
2435 /* We caught the SIGSTOP that we intended to catch, so
2436 there's no SIGSTOP pending. */
2438 if (debug_linux_nat)
2439 fprintf_unfiltered (gdb_stdlog,
2440 "SWC: Expected SIGSTOP caught for %s.\n",
2441 target_pid_to_str (lp->ptid));
2443 /* Reset SIGNALLED only after the stop_wait_callback call
2444 above as it does gdb_assert on SIGNALLED. */
2452 /* Return non-zero if LP has a wait status pending. Discard the
2453 pending event and resume the LWP if the event that originally
2454 caused the stop became uninteresting. */
2457 status_callback (struct lwp_info *lp, void *data)
2459 /* Only report a pending wait status if we pretend that this has
2460 indeed been resumed. */
2464 if (!lwp_status_pending_p (lp))
2467 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
2468 || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2470 struct regcache *regcache = get_thread_regcache (lp->ptid);
2474 pc = regcache_read_pc (regcache);
2476 if (pc != lp->stop_pc)
2478 if (debug_linux_nat)
2479 fprintf_unfiltered (gdb_stdlog,
2480 "SC: PC of %s changed. was=%s, now=%s\n",
2481 target_pid_to_str (lp->ptid),
2482 paddress (target_gdbarch (), lp->stop_pc),
2483 paddress (target_gdbarch (), pc));
2487 #if !USE_SIGTRAP_SIGINFO
2488 else if (!breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2490 if (debug_linux_nat)
2491 fprintf_unfiltered (gdb_stdlog,
2492 "SC: previous breakpoint of %s, at %s gone\n",
2493 target_pid_to_str (lp->ptid),
2494 paddress (target_gdbarch (), lp->stop_pc));
2502 if (debug_linux_nat)
2503 fprintf_unfiltered (gdb_stdlog,
2504 "SC: pending event of %s cancelled.\n",
2505 target_pid_to_str (lp->ptid));
2508 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
2516 /* Count the LWP's that have had events. */
2519 count_events_callback (struct lwp_info *lp, void *data)
2521 int *count = (int *) data;
2523 gdb_assert (count != NULL);
2525 /* Select only resumed LWPs that have an event pending. */
2526 if (lp->resumed && lwp_status_pending_p (lp))
2532 /* Select the LWP (if any) that is currently being single-stepped. */
2535 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2537 if (lp->last_resume_kind == resume_step
2544 /* Returns true if LP has a status pending. */
2547 lwp_status_pending_p (struct lwp_info *lp)
2549 /* We check for lp->waitstatus in addition to lp->status, because we
2550 can have pending process exits recorded in lp->status and
2551 W_EXITCODE(0,0) happens to be 0. */
2552 return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE;
2555 /* Select the Nth LWP that has had an event. */
2558 select_event_lwp_callback (struct lwp_info *lp, void *data)
2560 int *selector = (int *) data;
2562 gdb_assert (selector != NULL);
2564 /* Select only resumed LWPs that have an event pending. */
2565 if (lp->resumed && lwp_status_pending_p (lp))
2566 if ((*selector)-- == 0)
2572 /* Called when the LWP stopped for a signal/trap. If it stopped for a
2573 trap check what caused it (breakpoint, watchpoint, trace, etc.),
2574 and save the result in the LWP's stop_reason field. If it stopped
2575 for a breakpoint, decrement the PC if necessary on the lwp's
2579 save_stop_reason (struct lwp_info *lp)
2581 struct regcache *regcache;
2582 struct gdbarch *gdbarch;
2585 #if USE_SIGTRAP_SIGINFO
2589 gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
2590 gdb_assert (lp->status != 0);
2592 if (!linux_nat_status_is_event (lp->status))
2595 regcache = get_thread_regcache (lp->ptid);
2596 gdbarch = get_regcache_arch (regcache);
2598 pc = regcache_read_pc (regcache);
2599 sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch);
2601 #if USE_SIGTRAP_SIGINFO
2602 if (linux_nat_get_siginfo (lp->ptid, &siginfo))
2604 if (siginfo.si_signo == SIGTRAP)
2606 if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code)
2607 && GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
2609 /* The si_code is ambiguous on this arch -- check debug
2611 if (!check_stopped_by_watchpoint (lp))
2612 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2614 else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code))
2616 /* If we determine the LWP stopped for a SW breakpoint,
2617 trust it. Particularly don't check watchpoint
2618 registers, because at least on s390, we'd find
2619 stopped-by-watchpoint as long as there's a watchpoint
2621 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2623 else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
2625 /* This can indicate either a hardware breakpoint or
2626 hardware watchpoint. Check debug registers. */
2627 if (!check_stopped_by_watchpoint (lp))
2628 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2630 else if (siginfo.si_code == TRAP_TRACE)
2632 if (debug_linux_nat)
2633 fprintf_unfiltered (gdb_stdlog,
2634 "CSBB: %s stopped by trace\n",
2635 target_pid_to_str (lp->ptid));
2637 /* We may have single stepped an instruction that
2638 triggered a watchpoint. In that case, on some
2639 architectures (such as x86), instead of TRAP_HWBKPT,
2640 si_code indicates TRAP_TRACE, and we need to check
2641 the debug registers separately. */
2642 check_stopped_by_watchpoint (lp);
2647 if ((!lp->step || lp->stop_pc == sw_bp_pc)
2648 && software_breakpoint_inserted_here_p (get_regcache_aspace (regcache),
2651 /* The LWP was either continued, or stepped a software
2652 breakpoint instruction. */
2653 lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
2656 if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2657 lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
2659 if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON)
2660 check_stopped_by_watchpoint (lp);
2663 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT)
2665 if (debug_linux_nat)
2666 fprintf_unfiltered (gdb_stdlog,
2667 "CSBB: %s stopped by software breakpoint\n",
2668 target_pid_to_str (lp->ptid));
2670 /* Back up the PC if necessary. */
2672 regcache_write_pc (regcache, sw_bp_pc);
2674 /* Update this so we record the correct stop PC below. */
2677 else if (lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
2679 if (debug_linux_nat)
2680 fprintf_unfiltered (gdb_stdlog,
2681 "CSBB: %s stopped by hardware breakpoint\n",
2682 target_pid_to_str (lp->ptid));
2684 else if (lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT)
2686 if (debug_linux_nat)
2687 fprintf_unfiltered (gdb_stdlog,
2688 "CSBB: %s stopped by hardware watchpoint\n",
2689 target_pid_to_str (lp->ptid));
2696 /* Returns true if the LWP had stopped for a software breakpoint. */
2699 linux_nat_stopped_by_sw_breakpoint (struct target_ops *ops)
2701 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2703 gdb_assert (lp != NULL);
2705 return lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT;
2708 /* Implement the supports_stopped_by_sw_breakpoint method. */
2711 linux_nat_supports_stopped_by_sw_breakpoint (struct target_ops *ops)
2713 return USE_SIGTRAP_SIGINFO;
2716 /* Returns true if the LWP had stopped for a hardware
2717 breakpoint/watchpoint. */
2720 linux_nat_stopped_by_hw_breakpoint (struct target_ops *ops)
2722 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2724 gdb_assert (lp != NULL);
2726 return lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT;
2729 /* Implement the supports_stopped_by_hw_breakpoint method. */
2732 linux_nat_supports_stopped_by_hw_breakpoint (struct target_ops *ops)
2734 return USE_SIGTRAP_SIGINFO;
2737 /* Select one LWP out of those that have events pending. */
2740 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2743 int random_selector;
2744 struct lwp_info *event_lp = NULL;
2746 /* Record the wait status for the original LWP. */
2747 (*orig_lp)->status = *status;
2749 /* In all-stop, give preference to the LWP that is being
2750 single-stepped. There will be at most one, and it will be the
2751 LWP that the core is most interested in. If we didn't do this,
2752 then we'd have to handle pending step SIGTRAPs somehow in case
2753 the core later continues the previously-stepped thread, as
2754 otherwise we'd report the pending SIGTRAP then, and the core, not
2755 having stepped the thread, wouldn't understand what the trap was
2756 for, and therefore would report it to the user as a random
2758 if (!target_is_non_stop_p ())
2760 event_lp = iterate_over_lwps (filter,
2761 select_singlestep_lwp_callback, NULL);
2762 if (event_lp != NULL)
2764 if (debug_linux_nat)
2765 fprintf_unfiltered (gdb_stdlog,
2766 "SEL: Select single-step %s\n",
2767 target_pid_to_str (event_lp->ptid));
2771 if (event_lp == NULL)
2773 /* Pick one at random, out of those which have had events. */
2775 /* First see how many events we have. */
2776 iterate_over_lwps (filter, count_events_callback, &num_events);
2777 gdb_assert (num_events > 0);
2779 /* Now randomly pick a LWP out of those that have had
2781 random_selector = (int)
2782 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2784 if (debug_linux_nat && num_events > 1)
2785 fprintf_unfiltered (gdb_stdlog,
2786 "SEL: Found %d events, selecting #%d\n",
2787 num_events, random_selector);
2789 event_lp = iterate_over_lwps (filter,
2790 select_event_lwp_callback,
2794 if (event_lp != NULL)
2796 /* Switch the event LWP. */
2797 *orig_lp = event_lp;
2798 *status = event_lp->status;
2801 /* Flush the wait status for the event LWP. */
2802 (*orig_lp)->status = 0;
2805 /* Return non-zero if LP has been resumed. */
2808 resumed_callback (struct lwp_info *lp, void *data)
2813 /* Check if we should go on and pass this event to common code.
2814 Return the affected lwp if we are, or NULL otherwise. */
2816 static struct lwp_info *
2817 linux_nat_filter_event (int lwpid, int status)
2819 struct lwp_info *lp;
2820 int event = linux_ptrace_get_extended_event (status);
2822 lp = find_lwp_pid (pid_to_ptid (lwpid));
2824 /* Check for stop events reported by a process we didn't already
2825 know about - anything not already in our LWP list.
2827 If we're expecting to receive stopped processes after
2828 fork, vfork, and clone events, then we'll just add the
2829 new one to our list and go back to waiting for the event
2830 to be reported - the stopped process might be returned
2831 from waitpid before or after the event is.
2833 But note the case of a non-leader thread exec'ing after the
2834 leader having exited, and gone from our lists. The non-leader
2835 thread changes its tid to the tgid. */
2837 if (WIFSTOPPED (status) && lp == NULL
2838 && (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
2840 /* A multi-thread exec after we had seen the leader exiting. */
2841 if (debug_linux_nat)
2842 fprintf_unfiltered (gdb_stdlog,
2843 "LLW: Re-adding thread group leader LWP %d.\n",
2846 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2849 add_thread (lp->ptid);
2852 if (WIFSTOPPED (status) && !lp)
2854 if (debug_linux_nat)
2855 fprintf_unfiltered (gdb_stdlog,
2856 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2857 (long) lwpid, status_to_str (status));
2858 add_to_pid_list (&stopped_pids, lwpid, status);
2862 /* Make sure we don't report an event for the exit of an LWP not in
2863 our list, i.e. not part of the current process. This can happen
2864 if we detach from a program we originally forked and then it
2866 if (!WIFSTOPPED (status) && !lp)
2869 /* This LWP is stopped now. (And if dead, this prevents it from
2870 ever being continued.) */
2873 if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
2875 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2876 int options = linux_nat_ptrace_options (inf->attach_flag);
2878 linux_enable_event_reporting (ptid_get_lwp (lp->ptid), options);
2879 lp->must_set_ptrace_flags = 0;
2882 /* Handle GNU/Linux's syscall SIGTRAPs. */
2883 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2885 /* No longer need the sysgood bit. The ptrace event ends up
2886 recorded in lp->waitstatus if we care for it. We can carry
2887 on handling the event like a regular SIGTRAP from here
2889 status = W_STOPCODE (SIGTRAP);
2890 if (linux_handle_syscall_trap (lp, 0))
2895 /* Almost all other ptrace-stops are known to be outside of system
2896 calls, with further exceptions in linux_handle_extended_wait. */
2897 lp->syscall_state = TARGET_WAITKIND_IGNORE;
2900 /* Handle GNU/Linux's extended waitstatus for trace events. */
2901 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
2902 && linux_is_extended_waitstatus (status))
2904 if (debug_linux_nat)
2905 fprintf_unfiltered (gdb_stdlog,
2906 "LLW: Handling extended status 0x%06x\n",
2908 if (linux_handle_extended_wait (lp, status))
2912 /* Check if the thread has exited. */
2913 if (WIFEXITED (status) || WIFSIGNALED (status))
2915 if (!report_thread_events
2916 && num_lwps (ptid_get_pid (lp->ptid)) > 1)
2918 if (debug_linux_nat)
2919 fprintf_unfiltered (gdb_stdlog,
2920 "LLW: %s exited.\n",
2921 target_pid_to_str (lp->ptid));
2923 /* If there is at least one more LWP, then the exit signal
2924 was not the end of the debugged application and should be
2930 /* Note that even if the leader was ptrace-stopped, it can still
2931 exit, if e.g., some other thread brings down the whole
2932 process (calls `exit'). So don't assert that the lwp is
2934 if (debug_linux_nat)
2935 fprintf_unfiltered (gdb_stdlog,
2936 "LWP %ld exited (resumed=%d)\n",
2937 ptid_get_lwp (lp->ptid), lp->resumed);
2939 /* Dead LWP's aren't expected to reported a pending sigstop. */
2942 /* Store the pending event in the waitstatus, because
2943 W_EXITCODE(0,0) == 0. */
2944 store_waitstatus (&lp->waitstatus, status);
2948 /* Make sure we don't report a SIGSTOP that we sent ourselves in
2949 an attempt to stop an LWP. */
2951 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
2955 if (lp->last_resume_kind == resume_stop)
2957 if (debug_linux_nat)
2958 fprintf_unfiltered (gdb_stdlog,
2959 "LLW: resume_stop SIGSTOP caught for %s.\n",
2960 target_pid_to_str (lp->ptid));
2964 /* This is a delayed SIGSTOP. Filter out the event. */
2966 if (debug_linux_nat)
2967 fprintf_unfiltered (gdb_stdlog,
2968 "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
2970 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2971 target_pid_to_str (lp->ptid));
2973 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
2974 gdb_assert (lp->resumed);
2979 /* Make sure we don't report a SIGINT that we have already displayed
2980 for another thread. */
2981 if (lp->ignore_sigint
2982 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
2984 if (debug_linux_nat)
2985 fprintf_unfiltered (gdb_stdlog,
2986 "LLW: Delayed SIGINT caught for %s.\n",
2987 target_pid_to_str (lp->ptid));
2989 /* This is a delayed SIGINT. */
2990 lp->ignore_sigint = 0;
2992 linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
2993 if (debug_linux_nat)
2994 fprintf_unfiltered (gdb_stdlog,
2995 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
2997 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2998 target_pid_to_str (lp->ptid));
2999 gdb_assert (lp->resumed);
3001 /* Discard the event. */
3005 /* Don't report signals that GDB isn't interested in, such as
3006 signals that are neither printed nor stopped upon. Stopping all
3007 threads can be a bit time-consuming so if we want decent
3008 performance with heavily multi-threaded programs, especially when
3009 they're using a high frequency timer, we'd better avoid it if we
3011 if (WIFSTOPPED (status))
3013 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3015 if (!target_is_non_stop_p ())
3017 /* Only do the below in all-stop, as we currently use SIGSTOP
3018 to implement target_stop (see linux_nat_stop) in
3020 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3022 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3023 forwarded to the entire process group, that is, all LWPs
3024 will receive it - unless they're using CLONE_THREAD to
3025 share signals. Since we only want to report it once, we
3026 mark it as ignored for all LWPs except this one. */
3027 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3028 set_ignore_sigint, NULL);
3029 lp->ignore_sigint = 0;
3032 maybe_clear_ignore_sigint (lp);
3035 /* When using hardware single-step, we need to report every signal.
3036 Otherwise, signals in pass_mask may be short-circuited
3037 except signals that might be caused by a breakpoint. */
3039 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status))
3040 && !linux_wstatus_maybe_breakpoint (status))
3042 linux_resume_one_lwp (lp, lp->step, signo);
3043 if (debug_linux_nat)
3044 fprintf_unfiltered (gdb_stdlog,
3045 "LLW: %s %s, %s (preempt 'handle')\n",
3047 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3048 target_pid_to_str (lp->ptid),
3049 (signo != GDB_SIGNAL_0
3050 ? strsignal (gdb_signal_to_host (signo))
3056 /* An interesting event. */
3058 lp->status = status;
3059 save_stop_reason (lp);
3063 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3064 their exits until all other threads in the group have exited. */
3067 check_zombie_leaders (void)
3069 struct inferior *inf;
3073 struct lwp_info *leader_lp;
3078 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3079 if (leader_lp != NULL
3080 /* Check if there are other threads in the group, as we may
3081 have raced with the inferior simply exiting. */
3082 && num_lwps (inf->pid) > 1
3083 && linux_proc_pid_is_zombie (inf->pid))
3085 if (debug_linux_nat)
3086 fprintf_unfiltered (gdb_stdlog,
3087 "CZL: Thread group leader %d zombie "
3088 "(it exited, or another thread execd).\n",
3091 /* A leader zombie can mean one of two things:
3093 - It exited, and there's an exit status pending
3094 available, or only the leader exited (not the whole
3095 program). In the latter case, we can't waitpid the
3096 leader's exit status until all other threads are gone.
3098 - There are 3 or more threads in the group, and a thread
3099 other than the leader exec'd. See comments on exec
3100 events at the top of the file. We could try
3101 distinguishing the exit and exec cases, by waiting once
3102 more, and seeing if something comes out, but it doesn't
3103 sound useful. The previous leader _does_ go away, and
3104 we'll re-add the new one once we see the exec event
3105 (which is just the same as what would happen if the
3106 previous leader did exit voluntarily before some other
3109 if (debug_linux_nat)
3110 fprintf_unfiltered (gdb_stdlog,
3111 "CZL: Thread group leader %d vanished.\n",
3113 exit_lwp (leader_lp);
3118 /* Convenience function that is called when the kernel reports an exit
3119 event. This decides whether to report the event to GDB as a
3120 process exit event, a thread exit event, or to suppress the
3124 filter_exit_event (struct lwp_info *event_child,
3125 struct target_waitstatus *ourstatus)
3127 ptid_t ptid = event_child->ptid;
3129 if (num_lwps (ptid_get_pid (ptid)) > 1)
3131 if (report_thread_events)
3132 ourstatus->kind = TARGET_WAITKIND_THREAD_EXITED;
3134 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3136 exit_lwp (event_child);
3143 linux_nat_wait_1 (struct target_ops *ops,
3144 ptid_t ptid, struct target_waitstatus *ourstatus,
3148 enum resume_kind last_resume_kind;
3149 struct lwp_info *lp;
3152 if (debug_linux_nat)
3153 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3155 /* The first time we get here after starting a new inferior, we may
3156 not have added it to the LWP list yet - this is the earliest
3157 moment at which we know its PID. */
3158 if (ptid_is_pid (inferior_ptid))
3160 /* Upgrade the main thread's ptid. */
3161 thread_change_ptid (inferior_ptid,
3162 ptid_build (ptid_get_pid (inferior_ptid),
3163 ptid_get_pid (inferior_ptid), 0));
3165 lp = add_initial_lwp (inferior_ptid);
3169 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3170 block_child_signals (&prev_mask);
3172 /* First check if there is a LWP with a wait status pending. */
3173 lp = iterate_over_lwps (ptid, status_callback, NULL);
3176 if (debug_linux_nat)
3177 fprintf_unfiltered (gdb_stdlog,
3178 "LLW: Using pending wait status %s for %s.\n",
3179 status_to_str (lp->status),
3180 target_pid_to_str (lp->ptid));
3183 /* But if we don't find a pending event, we'll have to wait. Always
3184 pull all events out of the kernel. We'll randomly select an
3185 event LWP out of all that have events, to prevent starvation. */
3191 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3194 - If the thread group leader exits while other threads in the
3195 thread group still exist, waitpid(TGID, ...) hangs. That
3196 waitpid won't return an exit status until the other threads
3197 in the group are reapped.
3199 - When a non-leader thread execs, that thread just vanishes
3200 without reporting an exit (so we'd hang if we waited for it
3201 explicitly in that case). The exec event is reported to
3205 lwpid = my_waitpid (-1, &status, __WALL | WNOHANG);
3207 if (debug_linux_nat)
3208 fprintf_unfiltered (gdb_stdlog,
3209 "LNW: waitpid(-1, ...) returned %d, %s\n",
3210 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3214 if (debug_linux_nat)
3216 fprintf_unfiltered (gdb_stdlog,
3217 "LLW: waitpid %ld received %s\n",
3218 (long) lwpid, status_to_str (status));
3221 linux_nat_filter_event (lwpid, status);
3222 /* Retry until nothing comes out of waitpid. A single
3223 SIGCHLD can indicate more than one child stopped. */
3227 /* Now that we've pulled all events out of the kernel, resume
3228 LWPs that don't have an interesting event to report. */
3229 iterate_over_lwps (minus_one_ptid,
3230 resume_stopped_resumed_lwps, &minus_one_ptid);
3232 /* ... and find an LWP with a status to report to the core, if
3234 lp = iterate_over_lwps (ptid, status_callback, NULL);
3238 /* Check for zombie thread group leaders. Those can't be reaped
3239 until all other threads in the thread group are. */
3240 check_zombie_leaders ();
3242 /* If there are no resumed children left, bail. We'd be stuck
3243 forever in the sigsuspend call below otherwise. */
3244 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3246 if (debug_linux_nat)
3247 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3249 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3251 restore_child_signals_mask (&prev_mask);
3252 return minus_one_ptid;
3255 /* No interesting event to report to the core. */
3257 if (target_options & TARGET_WNOHANG)
3259 if (debug_linux_nat)
3260 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3262 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3263 restore_child_signals_mask (&prev_mask);
3264 return minus_one_ptid;
3267 /* We shouldn't end up here unless we want to try again. */
3268 gdb_assert (lp == NULL);
3270 /* Block until we get an event reported with SIGCHLD. */
3271 if (debug_linux_nat)
3272 fprintf_unfiltered (gdb_stdlog, "LNW: about to sigsuspend\n");
3273 sigsuspend (&suspend_mask);
3278 status = lp->status;
3281 if (!target_is_non_stop_p ())
3283 /* Now stop all other LWP's ... */
3284 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3286 /* ... and wait until all of them have reported back that
3287 they're no longer running. */
3288 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3291 /* If we're not waiting for a specific LWP, choose an event LWP from
3292 among those that have had events. Giving equal priority to all
3293 LWPs that have had events helps prevent starvation. */
3294 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3295 select_event_lwp (ptid, &lp, &status);
3297 gdb_assert (lp != NULL);
3299 /* Now that we've selected our final event LWP, un-adjust its PC if
3300 it was a software breakpoint, and we can't reliably support the
3301 "stopped by software breakpoint" stop reason. */
3302 if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
3303 && !USE_SIGTRAP_SIGINFO)
3305 struct regcache *regcache = get_thread_regcache (lp->ptid);
3306 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3307 int decr_pc = gdbarch_decr_pc_after_break (gdbarch);
3313 pc = regcache_read_pc (regcache);
3314 regcache_write_pc (regcache, pc + decr_pc);
3318 /* We'll need this to determine whether to report a SIGSTOP as
3319 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3321 last_resume_kind = lp->last_resume_kind;
3323 if (!target_is_non_stop_p ())
3325 /* In all-stop, from the core's perspective, all LWPs are now
3326 stopped until a new resume action is sent over. */
3327 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3331 resume_clear_callback (lp, NULL);
3334 if (linux_nat_status_is_event (status))
3336 if (debug_linux_nat)
3337 fprintf_unfiltered (gdb_stdlog,
3338 "LLW: trap ptid is %s.\n",
3339 target_pid_to_str (lp->ptid));
3342 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3344 *ourstatus = lp->waitstatus;
3345 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3348 store_waitstatus (ourstatus, status);
3350 if (debug_linux_nat)
3351 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3353 restore_child_signals_mask (&prev_mask);
3355 if (last_resume_kind == resume_stop
3356 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3357 && WSTOPSIG (status) == SIGSTOP)
3359 /* A thread that has been requested to stop by GDB with
3360 target_stop, and it stopped cleanly, so report as SIG0. The
3361 use of SIGSTOP is an implementation detail. */
3362 ourstatus->value.sig = GDB_SIGNAL_0;
3365 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3366 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3369 lp->core = linux_common_core_of_thread (lp->ptid);
3371 if (ourstatus->kind == TARGET_WAITKIND_EXITED)
3372 return filter_exit_event (lp, ourstatus);
3377 /* Resume LWPs that are currently stopped without any pending status
3378 to report, but are resumed from the core's perspective. */
3381 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3383 ptid_t *wait_ptid_p = (ptid_t *) data;
3387 if (debug_linux_nat)
3388 fprintf_unfiltered (gdb_stdlog,
3389 "RSRL: NOT resuming LWP %s, not stopped\n",
3390 target_pid_to_str (lp->ptid));
3392 else if (!lp->resumed)
3394 if (debug_linux_nat)
3395 fprintf_unfiltered (gdb_stdlog,
3396 "RSRL: NOT resuming LWP %s, not resumed\n",
3397 target_pid_to_str (lp->ptid));
3399 else if (lwp_status_pending_p (lp))
3401 if (debug_linux_nat)
3402 fprintf_unfiltered (gdb_stdlog,
3403 "RSRL: NOT resuming LWP %s, has pending status\n",
3404 target_pid_to_str (lp->ptid));
3408 struct regcache *regcache = get_thread_regcache (lp->ptid);
3409 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3413 CORE_ADDR pc = regcache_read_pc (regcache);
3414 int leave_stopped = 0;
3416 /* Don't bother if there's a breakpoint at PC that we'd hit
3417 immediately, and we're not waiting for this LWP. */
3418 if (!ptid_match (lp->ptid, *wait_ptid_p))
3420 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3426 if (debug_linux_nat)
3427 fprintf_unfiltered (gdb_stdlog,
3428 "RSRL: resuming stopped-resumed LWP %s at "
3430 target_pid_to_str (lp->ptid),
3431 paddress (gdbarch, pc),
3434 linux_resume_one_lwp_throw (lp, lp->step, GDB_SIGNAL_0);
3437 CATCH (ex, RETURN_MASK_ERROR)
3439 if (!check_ptrace_stopped_lwp_gone (lp))
3440 throw_exception (ex);
3449 linux_nat_wait (struct target_ops *ops,
3450 ptid_t ptid, struct target_waitstatus *ourstatus,
3455 if (debug_linux_nat)
3457 char *options_string;
3459 options_string = target_options_to_string (target_options);
3460 fprintf_unfiltered (gdb_stdlog,
3461 "linux_nat_wait: [%s], [%s]\n",
3462 target_pid_to_str (ptid),
3464 xfree (options_string);
3467 /* Flush the async file first. */
3468 if (target_is_async_p ())
3469 async_file_flush ();
3471 /* Resume LWPs that are currently stopped without any pending status
3472 to report, but are resumed from the core's perspective. LWPs get
3473 in this state if we find them stopping at a time we're not
3474 interested in reporting the event (target_wait on a
3475 specific_process, for example, see linux_nat_wait_1), and
3476 meanwhile the event became uninteresting. Don't bother resuming
3477 LWPs we're not going to wait for if they'd stop immediately. */
3478 if (target_is_non_stop_p ())
3479 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3481 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3483 /* If we requested any event, and something came out, assume there
3484 may be more. If we requested a specific lwp or process, also
3485 assume there may be more. */
3486 if (target_is_async_p ()
3487 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3488 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3489 || !ptid_equal (ptid, minus_one_ptid)))
3498 kill_one_lwp (pid_t pid)
3500 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3503 kill_lwp (pid, SIGKILL);
3504 if (debug_linux_nat)
3506 int save_errno = errno;
3508 fprintf_unfiltered (gdb_stdlog,
3509 "KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid,
3510 save_errno ? safe_strerror (save_errno) : "OK");
3513 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3516 ptrace (PTRACE_KILL, pid, 0, 0);
3517 if (debug_linux_nat)
3519 int save_errno = errno;
3521 fprintf_unfiltered (gdb_stdlog,
3522 "KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid,
3523 save_errno ? safe_strerror (save_errno) : "OK");
3527 /* Wait for an LWP to die. */
3530 kill_wait_one_lwp (pid_t pid)
3534 /* We must make sure that there are no pending events (delayed
3535 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3536 program doesn't interfere with any following debugging session. */
3540 res = my_waitpid (pid, NULL, __WALL);
3541 if (res != (pid_t) -1)
3543 if (debug_linux_nat)
3544 fprintf_unfiltered (gdb_stdlog,
3545 "KWC: wait %ld received unknown.\n",
3547 /* The Linux kernel sometimes fails to kill a thread
3548 completely after PTRACE_KILL; that goes from the stop
3549 point in do_fork out to the one in get_signal_to_deliver
3550 and waits again. So kill it again. */
3556 gdb_assert (res == -1 && errno == ECHILD);
3559 /* Callback for iterate_over_lwps. */
3562 kill_callback (struct lwp_info *lp, void *data)
3564 kill_one_lwp (ptid_get_lwp (lp->ptid));
3568 /* Callback for iterate_over_lwps. */
3571 kill_wait_callback (struct lwp_info *lp, void *data)
3573 kill_wait_one_lwp (ptid_get_lwp (lp->ptid));
3577 /* Kill the fork children of any threads of inferior INF that are
3578 stopped at a fork event. */
3581 kill_unfollowed_fork_children (struct inferior *inf)
3583 struct thread_info *thread;
3585 ALL_NON_EXITED_THREADS (thread)
3586 if (thread->inf == inf)
3588 struct target_waitstatus *ws = &thread->pending_follow;
3590 if (ws->kind == TARGET_WAITKIND_FORKED
3591 || ws->kind == TARGET_WAITKIND_VFORKED)
3593 ptid_t child_ptid = ws->value.related_pid;
3594 int child_pid = ptid_get_pid (child_ptid);
3595 int child_lwp = ptid_get_lwp (child_ptid);
3597 kill_one_lwp (child_lwp);
3598 kill_wait_one_lwp (child_lwp);
3600 /* Let the arch-specific native code know this process is
3602 linux_nat_forget_process (child_pid);
3608 linux_nat_kill (struct target_ops *ops)
3610 /* If we're stopped while forking and we haven't followed yet,
3611 kill the other task. We need to do this first because the
3612 parent will be sleeping if this is a vfork. */
3613 kill_unfollowed_fork_children (current_inferior ());
3615 if (forks_exist_p ())
3616 linux_fork_killall ();
3619 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3621 /* Stop all threads before killing them, since ptrace requires
3622 that the thread is stopped to sucessfully PTRACE_KILL. */
3623 iterate_over_lwps (ptid, stop_callback, NULL);
3624 /* ... and wait until all of them have reported back that
3625 they're no longer running. */
3626 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3628 /* Kill all LWP's ... */
3629 iterate_over_lwps (ptid, kill_callback, NULL);
3631 /* ... and wait until we've flushed all events. */
3632 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3635 target_mourn_inferior ();
3639 linux_nat_mourn_inferior (struct target_ops *ops)
3641 int pid = ptid_get_pid (inferior_ptid);
3643 purge_lwp_list (pid);
3645 if (! forks_exist_p ())
3646 /* Normal case, no other forks available. */
3647 linux_ops->to_mourn_inferior (ops);
3649 /* Multi-fork case. The current inferior_ptid has exited, but
3650 there are other viable forks to debug. Delete the exiting
3651 one and context-switch to the first available. */
3652 linux_fork_mourn_inferior ();
3654 /* Let the arch-specific native code know this process is gone. */
3655 linux_nat_forget_process (pid);
3658 /* Convert a native/host siginfo object, into/from the siginfo in the
3659 layout of the inferiors' architecture. */
3662 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3666 if (linux_nat_siginfo_fixup != NULL)
3667 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3669 /* If there was no callback, or the callback didn't do anything,
3670 then just do a straight memcpy. */
3674 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3676 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3680 static enum target_xfer_status
3681 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3682 const char *annex, gdb_byte *readbuf,
3683 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3684 ULONGEST *xfered_len)
3688 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3690 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3691 gdb_assert (readbuf || writebuf);
3693 pid = ptid_get_lwp (inferior_ptid);
3695 pid = ptid_get_pid (inferior_ptid);
3697 if (offset > sizeof (siginfo))
3698 return TARGET_XFER_E_IO;
3701 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3703 return TARGET_XFER_E_IO;
3705 /* When GDB is built as a 64-bit application, ptrace writes into
3706 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3707 inferior with a 64-bit GDB should look the same as debugging it
3708 with a 32-bit GDB, we need to convert it. GDB core always sees
3709 the converted layout, so any read/write will have to be done
3711 siginfo_fixup (&siginfo, inf_siginfo, 0);
3713 if (offset + len > sizeof (siginfo))
3714 len = sizeof (siginfo) - offset;
3716 if (readbuf != NULL)
3717 memcpy (readbuf, inf_siginfo + offset, len);
3720 memcpy (inf_siginfo + offset, writebuf, len);
3722 /* Convert back to ptrace layout before flushing it out. */
3723 siginfo_fixup (&siginfo, inf_siginfo, 1);
3726 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3728 return TARGET_XFER_E_IO;
3732 return TARGET_XFER_OK;
3735 static enum target_xfer_status
3736 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3737 const char *annex, gdb_byte *readbuf,
3738 const gdb_byte *writebuf,
3739 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3741 struct cleanup *old_chain;
3742 enum target_xfer_status xfer;
3744 if (object == TARGET_OBJECT_SIGNAL_INFO)
3745 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3746 offset, len, xfered_len);
3748 /* The target is connected but no live inferior is selected. Pass
3749 this request down to a lower stratum (e.g., the executable
3751 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3752 return TARGET_XFER_EOF;
3754 old_chain = save_inferior_ptid ();
3756 if (ptid_lwp_p (inferior_ptid))
3757 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3759 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3760 offset, len, xfered_len);
3762 do_cleanups (old_chain);
3767 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3769 /* As long as a PTID is in lwp list, consider it alive. */
3770 return find_lwp_pid (ptid) != NULL;
3773 /* Implement the to_update_thread_list target method for this
3777 linux_nat_update_thread_list (struct target_ops *ops)
3779 struct lwp_info *lwp;
3781 /* We add/delete threads from the list as clone/exit events are
3782 processed, so just try deleting exited threads still in the
3784 delete_exited_threads ();
3786 /* Update the processor core that each lwp/thread was last seen
3790 /* Avoid accessing /proc if the thread hasn't run since we last
3791 time we fetched the thread's core. Accessing /proc becomes
3792 noticeably expensive when we have thousands of LWPs. */
3793 if (lwp->core == -1)
3794 lwp->core = linux_common_core_of_thread (lwp->ptid);
3799 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3801 static char buf[64];
3803 if (ptid_lwp_p (ptid)
3804 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
3805 || num_lwps (ptid_get_pid (ptid)) > 1))
3807 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
3811 return normal_pid_to_str (ptid);
3815 linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
3817 return linux_proc_tid_get_name (thr->ptid);
3820 /* Accepts an integer PID; Returns a string representing a file that
3821 can be opened to get the symbols for the child process. */
3824 linux_child_pid_to_exec_file (struct target_ops *self, int pid)
3826 return linux_proc_pid_to_exec_file (pid);
3829 /* Implement the to_xfer_partial interface for memory reads using the /proc
3830 filesystem. Because we can use a single read() call for /proc, this
3831 can be much more efficient than banging away at PTRACE_PEEKTEXT,
3832 but it doesn't support writes. */
3834 static enum target_xfer_status
3835 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
3836 const char *annex, gdb_byte *readbuf,
3837 const gdb_byte *writebuf,
3838 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
3844 if (object != TARGET_OBJECT_MEMORY || !readbuf)
3845 return TARGET_XFER_EOF;
3847 /* Don't bother for one word. */
3848 if (len < 3 * sizeof (long))
3849 return TARGET_XFER_EOF;
3851 /* We could keep this file open and cache it - possibly one per
3852 thread. That requires some juggling, but is even faster. */
3853 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
3854 ptid_get_pid (inferior_ptid));
3855 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
3857 return TARGET_XFER_EOF;
3859 /* If pread64 is available, use it. It's faster if the kernel
3860 supports it (only one syscall), and it's 64-bit safe even on
3861 32-bit platforms (for instance, SPARC debugging a SPARC64
3864 if (pread64 (fd, readbuf, len, offset) != len)
3866 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
3875 return TARGET_XFER_EOF;
3879 return TARGET_XFER_OK;
3884 /* Enumerate spufs IDs for process PID. */
3886 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
3888 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
3890 LONGEST written = 0;
3893 struct dirent *entry;
3895 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
3896 dir = opendir (path);
3901 while ((entry = readdir (dir)) != NULL)
3907 fd = atoi (entry->d_name);
3911 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
3912 if (stat (path, &st) != 0)
3914 if (!S_ISDIR (st.st_mode))
3917 if (statfs (path, &stfs) != 0)
3919 if (stfs.f_type != SPUFS_MAGIC)
3922 if (pos >= offset && pos + 4 <= offset + len)
3924 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
3934 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
3935 object type, using the /proc file system. */
3937 static enum target_xfer_status
3938 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
3939 const char *annex, gdb_byte *readbuf,
3940 const gdb_byte *writebuf,
3941 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3946 int pid = ptid_get_pid (inferior_ptid);
3951 return TARGET_XFER_E_IO;
3954 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
3957 return TARGET_XFER_E_IO;
3959 return TARGET_XFER_EOF;
3962 *xfered_len = (ULONGEST) l;
3963 return TARGET_XFER_OK;
3968 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
3969 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
3971 return TARGET_XFER_E_IO;
3974 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
3977 return TARGET_XFER_EOF;
3981 ret = write (fd, writebuf, (size_t) len);
3983 ret = read (fd, readbuf, (size_t) len);
3988 return TARGET_XFER_E_IO;
3990 return TARGET_XFER_EOF;
3993 *xfered_len = (ULONGEST) ret;
3994 return TARGET_XFER_OK;
3999 /* Parse LINE as a signal set and add its set bits to SIGS. */
4002 add_line_to_sigset (const char *line, sigset_t *sigs)
4004 int len = strlen (line) - 1;
4008 if (line[len] != '\n')
4009 error (_("Could not parse signal set: %s"), line);
4017 if (*p >= '0' && *p <= '9')
4019 else if (*p >= 'a' && *p <= 'f')
4020 digit = *p - 'a' + 10;
4022 error (_("Could not parse signal set: %s"), line);
4027 sigaddset (sigs, signum + 1);
4029 sigaddset (sigs, signum + 2);
4031 sigaddset (sigs, signum + 3);
4033 sigaddset (sigs, signum + 4);
4039 /* Find process PID's pending signals from /proc/pid/status and set
4043 linux_proc_pending_signals (int pid, sigset_t *pending,
4044 sigset_t *blocked, sigset_t *ignored)
4047 char buffer[PATH_MAX], fname[PATH_MAX];
4048 struct cleanup *cleanup;
4050 sigemptyset (pending);
4051 sigemptyset (blocked);
4052 sigemptyset (ignored);
4053 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4054 procfile = gdb_fopen_cloexec (fname, "r");
4055 if (procfile == NULL)
4056 error (_("Could not open %s"), fname);
4057 cleanup = make_cleanup_fclose (procfile);
4059 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4061 /* Normal queued signals are on the SigPnd line in the status
4062 file. However, 2.6 kernels also have a "shared" pending
4063 queue for delivering signals to a thread group, so check for
4066 Unfortunately some Red Hat kernels include the shared pending
4067 queue but not the ShdPnd status field. */
4069 if (startswith (buffer, "SigPnd:\t"))
4070 add_line_to_sigset (buffer + 8, pending);
4071 else if (startswith (buffer, "ShdPnd:\t"))
4072 add_line_to_sigset (buffer + 8, pending);
4073 else if (startswith (buffer, "SigBlk:\t"))
4074 add_line_to_sigset (buffer + 8, blocked);
4075 else if (startswith (buffer, "SigIgn:\t"))
4076 add_line_to_sigset (buffer + 8, ignored);
4079 do_cleanups (cleanup);
4082 static enum target_xfer_status
4083 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4084 const char *annex, gdb_byte *readbuf,
4085 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4086 ULONGEST *xfered_len)
4088 gdb_assert (object == TARGET_OBJECT_OSDATA);
4090 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4091 if (*xfered_len == 0)
4092 return TARGET_XFER_EOF;
4094 return TARGET_XFER_OK;
4097 static enum target_xfer_status
4098 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4099 const char *annex, gdb_byte *readbuf,
4100 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4101 ULONGEST *xfered_len)
4103 enum target_xfer_status xfer;
4105 if (object == TARGET_OBJECT_AUXV)
4106 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4107 offset, len, xfered_len);
4109 if (object == TARGET_OBJECT_OSDATA)
4110 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4111 offset, len, xfered_len);
4113 if (object == TARGET_OBJECT_SPU)
4114 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4115 offset, len, xfered_len);
4117 /* GDB calculates all the addresses in possibly larget width of the address.
4118 Address width needs to be masked before its final use - either by
4119 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4121 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4123 if (object == TARGET_OBJECT_MEMORY)
4125 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4127 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4128 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4131 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4132 offset, len, xfered_len);
4133 if (xfer != TARGET_XFER_EOF)
4136 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4137 offset, len, xfered_len);
4141 cleanup_target_stop (void *arg)
4143 ptid_t *ptid = (ptid_t *) arg;
4145 gdb_assert (arg != NULL);
4148 target_resume (*ptid, 0, GDB_SIGNAL_0);
4151 static VEC(static_tracepoint_marker_p) *
4152 linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
4155 char s[IPA_CMD_BUF_SIZE];
4156 struct cleanup *old_chain;
4157 int pid = ptid_get_pid (inferior_ptid);
4158 VEC(static_tracepoint_marker_p) *markers = NULL;
4159 struct static_tracepoint_marker *marker = NULL;
4161 ptid_t ptid = ptid_build (pid, 0, 0);
4166 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4167 s[sizeof ("qTfSTM")] = 0;
4169 agent_run_command (pid, s, strlen (s) + 1);
4171 old_chain = make_cleanup (free_current_marker, &marker);
4172 make_cleanup (cleanup_target_stop, &ptid);
4177 marker = XCNEW (struct static_tracepoint_marker);
4181 parse_static_tracepoint_marker_definition (p, &p, marker);
4183 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4185 VEC_safe_push (static_tracepoint_marker_p,
4191 release_static_tracepoint_marker (marker);
4192 memset (marker, 0, sizeof (*marker));
4195 while (*p++ == ','); /* comma-separated list */
4197 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4198 s[sizeof ("qTsSTM")] = 0;
4199 agent_run_command (pid, s, strlen (s) + 1);
4203 do_cleanups (old_chain);
4208 /* Create a prototype generic GNU/Linux target. The client can override
4209 it with local methods. */
4212 linux_target_install_ops (struct target_ops *t)
4214 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4215 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4216 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4217 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4218 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4219 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4220 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4221 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4222 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4223 t->to_post_attach = linux_child_post_attach;
4224 t->to_follow_fork = linux_child_follow_fork;
4226 super_xfer_partial = t->to_xfer_partial;
4227 t->to_xfer_partial = linux_xfer_partial;
4229 t->to_static_tracepoint_markers_by_strid
4230 = linux_child_static_tracepoint_markers_by_strid;
4236 struct target_ops *t;
4238 t = inf_ptrace_target ();
4239 linux_target_install_ops (t);
4245 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4247 struct target_ops *t;
4249 t = inf_ptrace_trad_target (register_u_offset);
4250 linux_target_install_ops (t);
4255 /* target_is_async_p implementation. */
4258 linux_nat_is_async_p (struct target_ops *ops)
4260 return linux_is_async_p ();
4263 /* target_can_async_p implementation. */
4266 linux_nat_can_async_p (struct target_ops *ops)
4268 /* NOTE: palves 2008-03-21: We're only async when the user requests
4269 it explicitly with the "set target-async" command.
4270 Someday, linux will always be async. */
4271 return target_async_permitted;
4275 linux_nat_supports_non_stop (struct target_ops *self)
4280 /* to_always_non_stop_p implementation. */
4283 linux_nat_always_non_stop_p (struct target_ops *self)
4288 /* True if we want to support multi-process. To be removed when GDB
4289 supports multi-exec. */
4291 int linux_multi_process = 1;
4294 linux_nat_supports_multi_process (struct target_ops *self)
4296 return linux_multi_process;
4300 linux_nat_supports_disable_randomization (struct target_ops *self)
4302 #ifdef HAVE_PERSONALITY
4309 static int async_terminal_is_ours = 1;
4311 /* target_terminal_inferior implementation.
4313 This is a wrapper around child_terminal_inferior to add async support. */
4316 linux_nat_terminal_inferior (struct target_ops *self)
4318 child_terminal_inferior (self);
4320 /* Calls to target_terminal_*() are meant to be idempotent. */
4321 if (!async_terminal_is_ours)
4324 delete_file_handler (input_fd);
4325 async_terminal_is_ours = 0;
4329 /* target_terminal_ours implementation.
4331 This is a wrapper around child_terminal_ours to add async support (and
4332 implement the target_terminal_ours vs target_terminal_ours_for_output
4333 distinction). child_terminal_ours is currently no different than
4334 child_terminal_ours_for_output.
4335 We leave target_terminal_ours_for_output alone, leaving it to
4336 child_terminal_ours_for_output. */
4339 linux_nat_terminal_ours (struct target_ops *self)
4341 /* GDB should never give the terminal to the inferior if the
4342 inferior is running in the background (run&, continue&, etc.),
4343 but claiming it sure should. */
4344 child_terminal_ours (self);
4346 if (async_terminal_is_ours)
4349 clear_sigint_trap ();
4350 add_file_handler (input_fd, stdin_event_handler, 0);
4351 async_terminal_is_ours = 1;
4354 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4355 so we notice when any child changes state, and notify the
4356 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4357 above to wait for the arrival of a SIGCHLD. */
4360 sigchld_handler (int signo)
4362 int old_errno = errno;
4364 if (debug_linux_nat)
4365 ui_file_write_async_safe (gdb_stdlog,
4366 "sigchld\n", sizeof ("sigchld\n") - 1);
4368 if (signo == SIGCHLD
4369 && linux_nat_event_pipe[0] != -1)
4370 async_file_mark (); /* Let the event loop know that there are
4371 events to handle. */
4376 /* Callback registered with the target events file descriptor. */
4379 handle_target_event (int error, gdb_client_data client_data)
4381 inferior_event_handler (INF_REG_EVENT, NULL);
4384 /* Create/destroy the target events pipe. Returns previous state. */
4387 linux_async_pipe (int enable)
4389 int previous = linux_is_async_p ();
4391 if (previous != enable)
4395 /* Block child signals while we create/destroy the pipe, as
4396 their handler writes to it. */
4397 block_child_signals (&prev_mask);
4401 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4402 internal_error (__FILE__, __LINE__,
4403 "creating event pipe failed.");
4405 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4406 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4410 close (linux_nat_event_pipe[0]);
4411 close (linux_nat_event_pipe[1]);
4412 linux_nat_event_pipe[0] = -1;
4413 linux_nat_event_pipe[1] = -1;
4416 restore_child_signals_mask (&prev_mask);
4422 /* target_async implementation. */
4425 linux_nat_async (struct target_ops *ops, int enable)
4429 if (!linux_async_pipe (1))
4431 add_file_handler (linux_nat_event_pipe[0],
4432 handle_target_event, NULL);
4433 /* There may be pending events to handle. Tell the event loop
4440 delete_file_handler (linux_nat_event_pipe[0]);
4441 linux_async_pipe (0);
4446 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4450 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4454 if (debug_linux_nat)
4455 fprintf_unfiltered (gdb_stdlog,
4456 "LNSL: running -> suspending %s\n",
4457 target_pid_to_str (lwp->ptid));
4460 if (lwp->last_resume_kind == resume_stop)
4462 if (debug_linux_nat)
4463 fprintf_unfiltered (gdb_stdlog,
4464 "linux-nat: already stopping LWP %ld at "
4466 ptid_get_lwp (lwp->ptid));
4470 stop_callback (lwp, NULL);
4471 lwp->last_resume_kind = resume_stop;
4475 /* Already known to be stopped; do nothing. */
4477 if (debug_linux_nat)
4479 if (find_thread_ptid (lwp->ptid)->stop_requested)
4480 fprintf_unfiltered (gdb_stdlog,
4481 "LNSL: already stopped/stop_requested %s\n",
4482 target_pid_to_str (lwp->ptid));
4484 fprintf_unfiltered (gdb_stdlog,
4485 "LNSL: already stopped/no "
4486 "stop_requested yet %s\n",
4487 target_pid_to_str (lwp->ptid));
4494 linux_nat_stop (struct target_ops *self, ptid_t ptid)
4496 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4500 linux_nat_close (struct target_ops *self)
4502 /* Unregister from the event loop. */
4503 if (linux_nat_is_async_p (self))
4504 linux_nat_async (self, 0);
4506 if (linux_ops->to_close)
4507 linux_ops->to_close (linux_ops);
4512 /* When requests are passed down from the linux-nat layer to the
4513 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4514 used. The address space pointer is stored in the inferior object,
4515 but the common code that is passed such ptid can't tell whether
4516 lwpid is a "main" process id or not (it assumes so). We reverse
4517 look up the "main" process id from the lwp here. */
4519 static struct address_space *
4520 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4522 struct lwp_info *lwp;
4523 struct inferior *inf;
4526 if (ptid_get_lwp (ptid) == 0)
4528 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4530 lwp = find_lwp_pid (ptid);
4531 pid = ptid_get_pid (lwp->ptid);
4535 /* A (pid,lwpid,0) ptid. */
4536 pid = ptid_get_pid (ptid);
4539 inf = find_inferior_pid (pid);
4540 gdb_assert (inf != NULL);
4544 /* Return the cached value of the processor core for thread PTID. */
4547 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4549 struct lwp_info *info = find_lwp_pid (ptid);
4556 /* Implementation of to_filesystem_is_local. */
4559 linux_nat_filesystem_is_local (struct target_ops *ops)
4561 struct inferior *inf = current_inferior ();
4563 if (inf->fake_pid_p || inf->pid == 0)
4566 return linux_ns_same (inf->pid, LINUX_NS_MNT);
4569 /* Convert the INF argument passed to a to_fileio_* method
4570 to a process ID suitable for passing to its corresponding
4571 linux_mntns_* function. If INF is non-NULL then the
4572 caller is requesting the filesystem seen by INF. If INF
4573 is NULL then the caller is requesting the filesystem seen
4574 by the GDB. We fall back to GDB's filesystem in the case
4575 that INF is non-NULL but its PID is unknown. */
4578 linux_nat_fileio_pid_of (struct inferior *inf)
4580 if (inf == NULL || inf->fake_pid_p || inf->pid == 0)
4586 /* Implementation of to_fileio_open. */
4589 linux_nat_fileio_open (struct target_ops *self,
4590 struct inferior *inf, const char *filename,
4591 int flags, int mode, int warn_if_slow,
4598 if (fileio_to_host_openflags (flags, &nat_flags) == -1
4599 || fileio_to_host_mode (mode, &nat_mode) == -1)
4601 *target_errno = FILEIO_EINVAL;
4605 fd = linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf),
4606 filename, nat_flags, nat_mode);
4608 *target_errno = host_to_fileio_error (errno);
4613 /* Implementation of to_fileio_readlink. */
4616 linux_nat_fileio_readlink (struct target_ops *self,
4617 struct inferior *inf, const char *filename,
4624 len = linux_mntns_readlink (linux_nat_fileio_pid_of (inf),
4625 filename, buf, sizeof (buf));
4628 *target_errno = host_to_fileio_error (errno);
4632 ret = (char *) xmalloc (len + 1);
4633 memcpy (ret, buf, len);
4638 /* Implementation of to_fileio_unlink. */
4641 linux_nat_fileio_unlink (struct target_ops *self,
4642 struct inferior *inf, const char *filename,
4647 ret = linux_mntns_unlink (linux_nat_fileio_pid_of (inf),
4650 *target_errno = host_to_fileio_error (errno);
4655 /* Implementation of the to_thread_events method. */
4658 linux_nat_thread_events (struct target_ops *ops, int enable)
4660 report_thread_events = enable;
4664 linux_nat_add_target (struct target_ops *t)
4666 /* Save the provided single-threaded target. We save this in a separate
4667 variable because another target we've inherited from (e.g. inf-ptrace)
4668 may have saved a pointer to T; we want to use it for the final
4669 process stratum target. */
4670 linux_ops_saved = *t;
4671 linux_ops = &linux_ops_saved;
4673 /* Override some methods for multithreading. */
4674 t->to_create_inferior = linux_nat_create_inferior;
4675 t->to_attach = linux_nat_attach;
4676 t->to_detach = linux_nat_detach;
4677 t->to_resume = linux_nat_resume;
4678 t->to_wait = linux_nat_wait;
4679 t->to_pass_signals = linux_nat_pass_signals;
4680 t->to_xfer_partial = linux_nat_xfer_partial;
4681 t->to_kill = linux_nat_kill;
4682 t->to_mourn_inferior = linux_nat_mourn_inferior;
4683 t->to_thread_alive = linux_nat_thread_alive;
4684 t->to_update_thread_list = linux_nat_update_thread_list;
4685 t->to_pid_to_str = linux_nat_pid_to_str;
4686 t->to_thread_name = linux_nat_thread_name;
4687 t->to_has_thread_control = tc_schedlock;
4688 t->to_thread_address_space = linux_nat_thread_address_space;
4689 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4690 t->to_stopped_data_address = linux_nat_stopped_data_address;
4691 t->to_stopped_by_sw_breakpoint = linux_nat_stopped_by_sw_breakpoint;
4692 t->to_supports_stopped_by_sw_breakpoint = linux_nat_supports_stopped_by_sw_breakpoint;
4693 t->to_stopped_by_hw_breakpoint = linux_nat_stopped_by_hw_breakpoint;
4694 t->to_supports_stopped_by_hw_breakpoint = linux_nat_supports_stopped_by_hw_breakpoint;
4695 t->to_thread_events = linux_nat_thread_events;
4697 t->to_can_async_p = linux_nat_can_async_p;
4698 t->to_is_async_p = linux_nat_is_async_p;
4699 t->to_supports_non_stop = linux_nat_supports_non_stop;
4700 t->to_always_non_stop_p = linux_nat_always_non_stop_p;
4701 t->to_async = linux_nat_async;
4702 t->to_terminal_inferior = linux_nat_terminal_inferior;
4703 t->to_terminal_ours = linux_nat_terminal_ours;
4705 super_close = t->to_close;
4706 t->to_close = linux_nat_close;
4708 t->to_stop = linux_nat_stop;
4710 t->to_supports_multi_process = linux_nat_supports_multi_process;
4712 t->to_supports_disable_randomization
4713 = linux_nat_supports_disable_randomization;
4715 t->to_core_of_thread = linux_nat_core_of_thread;
4717 t->to_filesystem_is_local = linux_nat_filesystem_is_local;
4718 t->to_fileio_open = linux_nat_fileio_open;
4719 t->to_fileio_readlink = linux_nat_fileio_readlink;
4720 t->to_fileio_unlink = linux_nat_fileio_unlink;
4722 /* We don't change the stratum; this target will sit at
4723 process_stratum and thread_db will set at thread_stratum. This
4724 is a little strange, since this is a multi-threaded-capable
4725 target, but we want to be on the stack below thread_db, and we
4726 also want to be used for single-threaded processes. */
4731 /* Register a method to call whenever a new thread is attached. */
4733 linux_nat_set_new_thread (struct target_ops *t,
4734 void (*new_thread) (struct lwp_info *))
4736 /* Save the pointer. We only support a single registered instance
4737 of the GNU/Linux native target, so we do not need to map this to
4739 linux_nat_new_thread = new_thread;
4742 /* See declaration in linux-nat.h. */
4745 linux_nat_set_new_fork (struct target_ops *t,
4746 linux_nat_new_fork_ftype *new_fork)
4748 /* Save the pointer. */
4749 linux_nat_new_fork = new_fork;
4752 /* See declaration in linux-nat.h. */
4755 linux_nat_set_forget_process (struct target_ops *t,
4756 linux_nat_forget_process_ftype *fn)
4758 /* Save the pointer. */
4759 linux_nat_forget_process_hook = fn;
4762 /* See declaration in linux-nat.h. */
4765 linux_nat_forget_process (pid_t pid)
4767 if (linux_nat_forget_process_hook != NULL)
4768 linux_nat_forget_process_hook (pid);
4771 /* Register a method that converts a siginfo object between the layout
4772 that ptrace returns, and the layout in the architecture of the
4775 linux_nat_set_siginfo_fixup (struct target_ops *t,
4776 int (*siginfo_fixup) (siginfo_t *,
4780 /* Save the pointer. */
4781 linux_nat_siginfo_fixup = siginfo_fixup;
4784 /* Register a method to call prior to resuming a thread. */
4787 linux_nat_set_prepare_to_resume (struct target_ops *t,
4788 void (*prepare_to_resume) (struct lwp_info *))
4790 /* Save the pointer. */
4791 linux_nat_prepare_to_resume = prepare_to_resume;
4794 /* See linux-nat.h. */
4797 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4801 pid = ptid_get_lwp (ptid);
4803 pid = ptid_get_pid (ptid);
4806 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4809 memset (siginfo, 0, sizeof (*siginfo));
4815 /* See nat/linux-nat.h. */
4818 current_lwp_ptid (void)
4820 gdb_assert (ptid_lwp_p (inferior_ptid));
4821 return inferior_ptid;
4824 /* Provide a prototype to silence -Wmissing-prototypes. */
4825 extern initialize_file_ftype _initialize_linux_nat;
4828 _initialize_linux_nat (void)
4830 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4831 &debug_linux_nat, _("\
4832 Set debugging of GNU/Linux lwp module."), _("\
4833 Show debugging of GNU/Linux lwp module."), _("\
4834 Enables printf debugging output."),
4836 show_debug_linux_nat,
4837 &setdebuglist, &showdebuglist);
4839 add_setshow_boolean_cmd ("linux-namespaces", class_maintenance,
4840 &debug_linux_namespaces, _("\
4841 Set debugging of GNU/Linux namespaces module."), _("\
4842 Show debugging of GNU/Linux namespaces module."), _("\
4843 Enables printf debugging output."),
4846 &setdebuglist, &showdebuglist);
4848 /* Save this mask as the default. */
4849 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4851 /* Install a SIGCHLD handler. */
4852 sigchld_action.sa_handler = sigchld_handler;
4853 sigemptyset (&sigchld_action.sa_mask);
4854 sigchld_action.sa_flags = SA_RESTART;
4856 /* Make it the default. */
4857 sigaction (SIGCHLD, &sigchld_action, NULL);
4859 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4860 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
4861 sigdelset (&suspend_mask, SIGCHLD);
4863 sigemptyset (&blocked_mask);
4867 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4868 the GNU/Linux Threads library and therefore doesn't really belong
4871 /* Return the set of signals used by the threads library in *SET. */
4874 lin_thread_get_thread_signals (sigset_t *set)
4878 /* NPTL reserves the first two RT signals, but does not provide any
4879 way for the debugger to query the signal numbers - fortunately
4880 they don't change. */
4881 sigaddset (set, __SIGRTMIN);
4882 sigaddset (set, __SIGRTMIN + 1);