1 /* Low level interface to ptrace, for the remote server for GDB.
2 Copyright (C) 1995, 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
3 2006, 2007 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/>. */
21 #include "linux-low.h"
25 #include <sys/param.h>
27 #include <sys/ptrace.h>
30 #include <sys/ioctl.h>
36 #include <sys/syscall.h>
38 #ifndef PTRACE_GETSIGINFO
39 # define PTRACE_GETSIGINFO 0x4202
40 # define PTRACE_SETSIGINFO 0x4203
44 #if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__))
49 /* ``all_threads'' is keyed by the LWP ID - it should be the thread ID instead,
50 however. This requires changing the ID in place when we go from !using_threads
51 to using_threads, immediately.
53 ``all_processes'' is keyed by the process ID - which on Linux is (presently)
54 the same as the LWP ID. */
56 struct inferior_list all_processes;
58 /* FIXME this is a bit of a hack, and could be removed. */
61 /* FIXME make into a target method? */
64 static void linux_resume_one_process (struct inferior_list_entry *entry,
65 int step, int signal, siginfo_t *info);
66 static void linux_resume (struct thread_resume *resume_info);
67 static void stop_all_processes (void);
68 static int linux_wait_for_event (struct thread_info *child);
69 static int check_removed_breakpoint (struct process_info *event_child);
71 struct pending_signals
75 struct pending_signals *prev;
78 #define PTRACE_ARG3_TYPE long
79 #define PTRACE_XFER_TYPE long
81 #ifdef HAVE_LINUX_REGSETS
82 static int use_regsets_p = 1;
85 #define pid_of(proc) ((proc)->head.id)
87 /* FIXME: Delete eventually. */
88 #define inferior_pid (pid_of (get_thread_process (current_inferior)))
90 /* This function should only be called if the process got a SIGTRAP.
91 The SIGTRAP could mean several things.
93 On i386, where decr_pc_after_break is non-zero:
94 If we were single-stepping this process using PTRACE_SINGLESTEP,
95 we will get only the one SIGTRAP (even if the instruction we
96 stepped over was a breakpoint). The value of $eip will be the
98 If we continue the process using PTRACE_CONT, we will get a
99 SIGTRAP when we hit a breakpoint. The value of $eip will be
100 the instruction after the breakpoint (i.e. needs to be
101 decremented). If we report the SIGTRAP to GDB, we must also
102 report the undecremented PC. If we cancel the SIGTRAP, we
103 must resume at the decremented PC.
105 (Presumably, not yet tested) On a non-decr_pc_after_break machine
106 with hardware or kernel single-step:
107 If we single-step over a breakpoint instruction, our PC will
108 point at the following instruction. If we continue and hit a
109 breakpoint instruction, our PC will point at the breakpoint
115 CORE_ADDR stop_pc = (*the_low_target.get_pc) ();
117 if (get_thread_process (current_inferior)->stepping)
120 return stop_pc - the_low_target.decr_pc_after_break;
124 add_process (unsigned long pid)
126 struct process_info *process;
128 process = (struct process_info *) malloc (sizeof (*process));
129 memset (process, 0, sizeof (*process));
131 process->head.id = pid;
133 /* Default to tid == lwpid == pid. */
135 process->lwpid = pid;
137 add_inferior_to_list (&all_processes, &process->head);
142 /* Start an inferior process and returns its pid.
143 ALLARGS is a vector of program-name and args. */
146 linux_create_inferior (char *program, char **allargs)
151 #if defined(__UCLIBC__) && defined(HAS_NOMMU)
157 perror_with_name ("fork");
161 ptrace (PTRACE_TRACEME, 0, 0, 0);
163 signal (__SIGRTMIN + 1, SIG_DFL);
167 execv (program, allargs);
169 execvp (program, allargs);
171 fprintf (stderr, "Cannot exec %s: %s.\n", program,
177 new_process = add_process (pid);
178 add_thread (pid, new_process, pid);
183 /* Attach to an inferior process. */
186 linux_attach_lwp (unsigned long pid, unsigned long tid)
188 struct process_info *new_process;
190 if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
192 fprintf (stderr, "Cannot attach to process %ld: %s (%d)\n", pid,
193 strerror (errno), errno);
196 /* If we fail to attach to an LWP, just return. */
202 new_process = (struct process_info *) add_process (pid);
203 add_thread (tid, new_process, pid);
205 /* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH
206 brings it to a halt. We should ignore that SIGSTOP and resume the process
207 (unless this is the first process, in which case the flag will be cleared
210 On the other hand, if we are currently trying to stop all threads, we
211 should treat the new thread as if we had sent it a SIGSTOP. This works
212 because we are guaranteed that add_process added us to the end of the
213 list, and so the new thread has not yet reached wait_for_sigstop (but
215 if (! stopping_threads)
216 new_process->stop_expected = 1;
220 linux_attach (unsigned long pid)
222 struct process_info *process;
224 linux_attach_lwp (pid, pid);
226 /* Don't ignore the initial SIGSTOP if we just attached to this process.
227 It will be collected by wait shortly. */
228 process = (struct process_info *) find_inferior_id (&all_processes, pid);
229 process->stop_expected = 0;
234 /* Kill the inferior process. Make us have no inferior. */
237 linux_kill_one_process (struct inferior_list_entry *entry)
239 struct thread_info *thread = (struct thread_info *) entry;
240 struct process_info *process = get_thread_process (thread);
243 /* We avoid killing the first thread here, because of a Linux kernel (at
244 least 2.6.0-test7 through 2.6.8-rc4) bug; if we kill the parent before
245 the children get a chance to be reaped, it will remain a zombie
247 if (entry == all_threads.head)
252 ptrace (PTRACE_KILL, pid_of (process), 0, 0);
254 /* Make sure it died. The loop is most likely unnecessary. */
255 wstat = linux_wait_for_event (thread);
256 } while (WIFSTOPPED (wstat));
262 struct thread_info *thread = (struct thread_info *) all_threads.head;
263 struct process_info *process;
269 for_each_inferior (&all_threads, linux_kill_one_process);
271 /* See the comment in linux_kill_one_process. We did not kill the first
272 thread in the list, so do so now. */
273 process = get_thread_process (thread);
276 ptrace (PTRACE_KILL, pid_of (process), 0, 0);
278 /* Make sure it died. The loop is most likely unnecessary. */
279 wstat = linux_wait_for_event (thread);
280 } while (WIFSTOPPED (wstat));
284 linux_detach_one_process (struct inferior_list_entry *entry)
286 struct thread_info *thread = (struct thread_info *) entry;
287 struct process_info *process = get_thread_process (thread);
289 /* Make sure the process isn't stopped at a breakpoint that's
291 check_removed_breakpoint (process);
293 /* If this process is stopped but is expecting a SIGSTOP, then make
294 sure we take care of that now. This isn't absolutely guaranteed
295 to collect the SIGSTOP, but is fairly likely to. */
296 if (process->stop_expected)
298 /* Clear stop_expected, so that the SIGSTOP will be reported. */
299 process->stop_expected = 0;
300 if (process->stopped)
301 linux_resume_one_process (&process->head, 0, 0, NULL);
302 linux_wait_for_event (thread);
305 /* Flush any pending changes to the process's registers. */
306 regcache_invalidate_one ((struct inferior_list_entry *)
307 get_process_thread (process));
309 /* Finally, let it resume. */
310 ptrace (PTRACE_DETACH, pid_of (process), 0, 0);
316 delete_all_breakpoints ();
317 for_each_inferior (&all_threads, linux_detach_one_process);
325 extern unsigned long signal_pid;
329 ret = waitpid (signal_pid, &status, 0);
330 if (WIFEXITED (status) || WIFSIGNALED (status))
332 } while (ret != -1 || errno != ECHILD);
335 /* Return nonzero if the given thread is still alive. */
337 linux_thread_alive (unsigned long tid)
339 if (find_inferior_id (&all_threads, tid) != NULL)
345 /* Return nonzero if this process stopped at a breakpoint which
346 no longer appears to be inserted. Also adjust the PC
347 appropriately to resume where the breakpoint used to be. */
349 check_removed_breakpoint (struct process_info *event_child)
352 struct thread_info *saved_inferior;
354 if (event_child->pending_is_breakpoint == 0)
358 fprintf (stderr, "Checking for breakpoint in process %ld.\n",
361 saved_inferior = current_inferior;
362 current_inferior = get_process_thread (event_child);
364 stop_pc = get_stop_pc ();
366 /* If the PC has changed since we stopped, then we shouldn't do
367 anything. This happens if, for instance, GDB handled the
368 decr_pc_after_break subtraction itself. */
369 if (stop_pc != event_child->pending_stop_pc)
372 fprintf (stderr, "Ignoring, PC was changed. Old PC was 0x%08llx\n",
373 event_child->pending_stop_pc);
375 event_child->pending_is_breakpoint = 0;
376 current_inferior = saved_inferior;
380 /* If the breakpoint is still there, we will report hitting it. */
381 if ((*the_low_target.breakpoint_at) (stop_pc))
384 fprintf (stderr, "Ignoring, breakpoint is still present.\n");
385 current_inferior = saved_inferior;
390 fprintf (stderr, "Removed breakpoint.\n");
392 /* For decr_pc_after_break targets, here is where we perform the
393 decrement. We go immediately from this function to resuming,
394 and can not safely call get_stop_pc () again. */
395 if (the_low_target.set_pc != NULL)
396 (*the_low_target.set_pc) (stop_pc);
398 /* We consumed the pending SIGTRAP. */
399 event_child->pending_is_breakpoint = 0;
400 event_child->status_pending_p = 0;
401 event_child->status_pending = 0;
403 current_inferior = saved_inferior;
407 /* Return 1 if this process has an interesting status pending. This function
408 may silently resume an inferior process. */
410 status_pending_p (struct inferior_list_entry *entry, void *dummy)
412 struct process_info *process = (struct process_info *) entry;
414 if (process->status_pending_p)
415 if (check_removed_breakpoint (process))
417 /* This thread was stopped at a breakpoint, and the breakpoint
418 is now gone. We were told to continue (or step...) all threads,
419 so GDB isn't trying to single-step past this breakpoint.
420 So instead of reporting the old SIGTRAP, pretend we got to
421 the breakpoint just after it was removed instead of just
422 before; resume the process. */
423 linux_resume_one_process (&process->head, 0, 0, NULL);
427 return process->status_pending_p;
431 linux_wait_for_process (struct process_info **childp, int *wstatp)
434 int to_wait_for = -1;
437 to_wait_for = (*childp)->lwpid;
441 ret = waitpid (to_wait_for, wstatp, WNOHANG);
446 perror_with_name ("waitpid");
451 ret = waitpid (to_wait_for, wstatp, WNOHANG | __WCLONE);
456 perror_with_name ("waitpid (WCLONE)");
465 && (!WIFSTOPPED (*wstatp)
466 || (WSTOPSIG (*wstatp) != 32
467 && WSTOPSIG (*wstatp) != 33)))
468 fprintf (stderr, "Got an event from %d (%x)\n", ret, *wstatp);
470 if (to_wait_for == -1)
471 *childp = (struct process_info *) find_inferior_id (&all_processes, ret);
473 (*childp)->stopped = 1;
474 (*childp)->pending_is_breakpoint = 0;
476 (*childp)->last_status = *wstatp;
479 && WIFSTOPPED (*wstatp))
481 current_inferior = (struct thread_info *)
482 find_inferior_id (&all_threads, (*childp)->tid);
483 /* For testing only; i386_stop_pc prints out a diagnostic. */
484 if (the_low_target.get_pc != NULL)
490 linux_wait_for_event (struct thread_info *child)
493 struct process_info *event_child;
496 /* Check for a process with a pending status. */
497 /* It is possible that the user changed the pending task's registers since
498 it stopped. We correctly handle the change of PC if we hit a breakpoint
499 (in check_removed_breakpoint); signals should be reported anyway. */
502 event_child = (struct process_info *)
503 find_inferior (&all_processes, status_pending_p, NULL);
504 if (debug_threads && event_child)
505 fprintf (stderr, "Got a pending child %ld\n", event_child->lwpid);
509 event_child = get_thread_process (child);
510 if (event_child->status_pending_p
511 && check_removed_breakpoint (event_child))
515 if (event_child != NULL)
517 if (event_child->status_pending_p)
520 fprintf (stderr, "Got an event from pending child %ld (%04x)\n",
521 event_child->lwpid, event_child->status_pending);
522 wstat = event_child->status_pending;
523 event_child->status_pending_p = 0;
524 event_child->status_pending = 0;
525 current_inferior = get_process_thread (event_child);
530 /* We only enter this loop if no process has a pending wait status. Thus
531 any action taken in response to a wait status inside this loop is
532 responding as soon as we detect the status, not after any pending
539 event_child = get_thread_process (child);
541 linux_wait_for_process (&event_child, &wstat);
543 if (event_child == NULL)
544 error ("event from unknown child");
546 current_inferior = (struct thread_info *)
547 find_inferior_id (&all_threads, event_child->tid);
549 /* Check for thread exit. */
550 if (using_threads && ! WIFSTOPPED (wstat))
553 fprintf (stderr, "Thread %ld (LWP %ld) exiting\n",
554 event_child->tid, event_child->head.id);
556 /* If the last thread is exiting, just return. */
557 if (all_threads.head == all_threads.tail)
560 dead_thread_notify (event_child->tid);
562 remove_inferior (&all_processes, &event_child->head);
564 remove_thread (current_inferior);
565 current_inferior = (struct thread_info *) all_threads.head;
567 /* If we were waiting for this particular child to do something...
568 well, it did something. */
572 /* Wait for a more interesting event. */
577 && WIFSTOPPED (wstat)
578 && WSTOPSIG (wstat) == SIGSTOP
579 && event_child->stop_expected)
582 fprintf (stderr, "Expected stop.\n");
583 event_child->stop_expected = 0;
584 linux_resume_one_process (&event_child->head,
585 event_child->stepping, 0, NULL);
589 /* If GDB is not interested in this signal, don't stop other
590 threads, and don't report it to GDB. Just resume the
591 inferior right away. We do this for threading-related
592 signals as well as any that GDB specifically requested
593 we ignore. But never ignore SIGSTOP if we sent it
595 /* FIXME drow/2002-06-09: Get signal numbers from the inferior's
597 if (WIFSTOPPED (wstat)
598 && ((using_threads && (WSTOPSIG (wstat) == __SIGRTMIN
599 || WSTOPSIG (wstat) == __SIGRTMIN + 1))
600 || (pass_signals[target_signal_from_host (WSTOPSIG (wstat))]
601 && (WSTOPSIG (wstat) != SIGSTOP
602 || !event_child->sigstop_sent))))
604 siginfo_t info, *info_p;
607 fprintf (stderr, "Ignored signal %d for %ld (LWP %ld).\n",
608 WSTOPSIG (wstat), event_child->tid,
609 event_child->head.id);
611 if (ptrace (PTRACE_GETSIGINFO, event_child->lwpid, 0, &info) == 0)
615 linux_resume_one_process (&event_child->head,
616 event_child->stepping,
617 WSTOPSIG (wstat), info_p);
621 /* If this event was not handled above, and is not a SIGTRAP, report
623 if (!WIFSTOPPED (wstat) || WSTOPSIG (wstat) != SIGTRAP)
626 /* If this target does not support breakpoints, we simply report the
627 SIGTRAP; it's of no concern to us. */
628 if (the_low_target.get_pc == NULL)
631 stop_pc = get_stop_pc ();
633 /* bp_reinsert will only be set if we were single-stepping.
634 Notice that we will resume the process after hitting
635 a gdbserver breakpoint; single-stepping to/over one
636 is not supported (yet). */
637 if (event_child->bp_reinsert != 0)
640 fprintf (stderr, "Reinserted breakpoint.\n");
641 reinsert_breakpoint (event_child->bp_reinsert);
642 event_child->bp_reinsert = 0;
644 /* Clear the single-stepping flag and SIGTRAP as we resume. */
645 linux_resume_one_process (&event_child->head, 0, 0, NULL);
650 fprintf (stderr, "Hit a (non-reinsert) breakpoint.\n");
652 if (check_breakpoints (stop_pc) != 0)
654 /* We hit one of our own breakpoints. We mark it as a pending
655 breakpoint, so that check_removed_breakpoint () will do the PC
656 adjustment for us at the appropriate time. */
657 event_child->pending_is_breakpoint = 1;
658 event_child->pending_stop_pc = stop_pc;
660 /* Now we need to put the breakpoint back. We continue in the event
661 loop instead of simply replacing the breakpoint right away,
662 in order to not lose signals sent to the thread that hit the
663 breakpoint. Unfortunately this increases the window where another
664 thread could sneak past the removed breakpoint. For the current
665 use of server-side breakpoints (thread creation) this is
666 acceptable; but it needs to be considered before this breakpoint
667 mechanism can be used in more general ways. For some breakpoints
668 it may be necessary to stop all other threads, but that should
669 be avoided where possible.
671 If breakpoint_reinsert_addr is NULL, that means that we can
672 use PTRACE_SINGLESTEP on this platform. Uninsert the breakpoint,
673 mark it for reinsertion, and single-step.
675 Otherwise, call the target function to figure out where we need
676 our temporary breakpoint, create it, and continue executing this
678 if (the_low_target.breakpoint_reinsert_addr == NULL)
680 event_child->bp_reinsert = stop_pc;
681 uninsert_breakpoint (stop_pc);
682 linux_resume_one_process (&event_child->head, 1, 0, NULL);
686 reinsert_breakpoint_by_bp
687 (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ());
688 linux_resume_one_process (&event_child->head, 0, 0, NULL);
694 /* If we were single-stepping, we definitely want to report the
695 SIGTRAP. The single-step operation has completed, so also
696 clear the stepping flag; in general this does not matter,
697 because the SIGTRAP will be reported to the client, which
698 will give us a new action for this thread, but clear it for
699 consistency anyway. It's safe to clear the stepping flag
700 because the only consumer of get_stop_pc () after this point
701 is check_removed_breakpoint, and pending_is_breakpoint is not
702 set. It might be wiser to use a step_completed flag instead. */
703 if (event_child->stepping)
705 event_child->stepping = 0;
709 /* A SIGTRAP that we can't explain. It may have been a breakpoint.
710 Check if it is a breakpoint, and if so mark the process information
711 accordingly. This will handle both the necessary fiddling with the
712 PC on decr_pc_after_break targets and suppressing extra threads
713 hitting a breakpoint if two hit it at once and then GDB removes it
714 after the first is reported. Arguably it would be better to report
715 multiple threads hitting breakpoints simultaneously, but the current
716 remote protocol does not allow this. */
717 if ((*the_low_target.breakpoint_at) (stop_pc))
719 event_child->pending_is_breakpoint = 1;
720 event_child->pending_stop_pc = stop_pc;
730 /* Wait for process, returns status. */
733 linux_wait (char *status)
736 struct thread_info *child = NULL;
739 /* If we were only supposed to resume one thread, only wait for
740 that thread - if it's still alive. If it died, however - which
741 can happen if we're coming from the thread death case below -
742 then we need to make sure we restart the other threads. We could
743 pick a thread at random or restart all; restarting all is less
745 if (cont_thread != 0 && cont_thread != -1)
747 child = (struct thread_info *) find_inferior_id (&all_threads,
750 /* No stepping, no signal - unless one is pending already, of course. */
753 struct thread_resume resume_info;
754 resume_info.thread = -1;
755 resume_info.step = resume_info.sig = resume_info.leave_stopped = 0;
756 linux_resume (&resume_info);
762 w = linux_wait_for_event (child);
763 stop_all_processes ();
766 /* If we are waiting for a particular child, and it exited,
767 linux_wait_for_event will return its exit status. Similarly if
768 the last child exited. If this is not the last child, however,
769 do not report it as exited until there is a 'thread exited' response
770 available in the remote protocol. Instead, just wait for another event.
771 This should be safe, because if the thread crashed we will already
772 have reported the termination signal to GDB; that should stop any
773 in-progress stepping operations, etc.
775 Report the exit status of the last thread to exit. This matches
776 LinuxThreads' behavior. */
778 if (all_threads.head == all_threads.tail)
782 fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
785 free (all_processes.head);
786 all_processes.head = all_processes.tail = NULL;
787 return WEXITSTATUS (w);
789 else if (!WIFSTOPPED (w))
791 fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
794 free (all_processes.head);
795 all_processes.head = all_processes.tail = NULL;
796 return target_signal_from_host (WTERMSIG (w));
806 return target_signal_from_host (WSTOPSIG (w));
809 /* Send a signal to an LWP. For LinuxThreads, kill is enough; however, if
810 thread groups are in use, we need to use tkill. */
813 kill_lwp (unsigned long lwpid, int signo)
815 static int tkill_failed;
822 int ret = syscall (SYS_tkill, lwpid, signo);
830 return kill (lwpid, signo);
834 send_sigstop (struct inferior_list_entry *entry)
836 struct process_info *process = (struct process_info *) entry;
838 if (process->stopped)
841 /* If we already have a pending stop signal for this process, don't
843 if (process->stop_expected)
846 fprintf (stderr, "Have pending sigstop for process %ld\n",
849 /* We clear the stop_expected flag so that wait_for_sigstop
850 will receive the SIGSTOP event (instead of silently resuming and
851 waiting again). It'll be reset below. */
852 process->stop_expected = 0;
857 fprintf (stderr, "Sending sigstop to process %ld\n", process->head.id);
859 kill_lwp (process->head.id, SIGSTOP);
860 process->sigstop_sent = 1;
864 wait_for_sigstop (struct inferior_list_entry *entry)
866 struct process_info *process = (struct process_info *) entry;
867 struct thread_info *saved_inferior, *thread;
869 unsigned long saved_tid;
871 if (process->stopped)
874 saved_inferior = current_inferior;
875 saved_tid = ((struct inferior_list_entry *) saved_inferior)->id;
876 thread = (struct thread_info *) find_inferior_id (&all_threads,
878 wstat = linux_wait_for_event (thread);
880 /* If we stopped with a non-SIGSTOP signal, save it for later
881 and record the pending SIGSTOP. If the process exited, just
883 if (WIFSTOPPED (wstat)
884 && WSTOPSIG (wstat) != SIGSTOP)
887 fprintf (stderr, "Process %ld (thread %ld) "
888 "stopped with non-sigstop status %06x\n",
889 process->lwpid, process->tid, wstat);
890 process->status_pending_p = 1;
891 process->status_pending = wstat;
892 process->stop_expected = 1;
895 if (linux_thread_alive (saved_tid))
896 current_inferior = saved_inferior;
900 fprintf (stderr, "Previously current thread died.\n");
902 /* Set a valid thread as current. */
903 set_desired_inferior (0);
908 stop_all_processes (void)
910 stopping_threads = 1;
911 for_each_inferior (&all_processes, send_sigstop);
912 for_each_inferior (&all_processes, wait_for_sigstop);
913 stopping_threads = 0;
916 /* Resume execution of the inferior process.
917 If STEP is nonzero, single-step it.
918 If SIGNAL is nonzero, give it that signal. */
921 linux_resume_one_process (struct inferior_list_entry *entry,
922 int step, int signal, siginfo_t *info)
924 struct process_info *process = (struct process_info *) entry;
925 struct thread_info *saved_inferior;
927 if (process->stopped == 0)
930 /* If we have pending signals or status, and a new signal, enqueue the
931 signal. Also enqueue the signal if we are waiting to reinsert a
932 breakpoint; it will be picked up again below. */
934 && (process->status_pending_p || process->pending_signals != NULL
935 || process->bp_reinsert != 0))
937 struct pending_signals *p_sig;
938 p_sig = malloc (sizeof (*p_sig));
939 p_sig->prev = process->pending_signals;
940 p_sig->signal = signal;
942 memset (&p_sig->info, 0, sizeof (siginfo_t));
944 memcpy (&p_sig->info, info, sizeof (siginfo_t));
945 process->pending_signals = p_sig;
948 if (process->status_pending_p && !check_removed_breakpoint (process))
951 saved_inferior = current_inferior;
952 current_inferior = get_process_thread (process);
955 fprintf (stderr, "Resuming process %ld (%s, signal %d, stop %s)\n", inferior_pid,
956 step ? "step" : "continue", signal,
957 process->stop_expected ? "expected" : "not expected");
959 /* This bit needs some thinking about. If we get a signal that
960 we must report while a single-step reinsert is still pending,
961 we often end up resuming the thread. It might be better to
962 (ew) allow a stack of pending events; then we could be sure that
963 the reinsert happened right away and not lose any signals.
965 Making this stack would also shrink the window in which breakpoints are
966 uninserted (see comment in linux_wait_for_process) but not enough for
967 complete correctness, so it won't solve that problem. It may be
968 worthwhile just to solve this one, however. */
969 if (process->bp_reinsert != 0)
972 fprintf (stderr, " pending reinsert at %08lx", (long)process->bp_reinsert);
974 fprintf (stderr, "BAD - reinserting but not stepping.\n");
977 /* Postpone any pending signal. It was enqueued above. */
981 check_removed_breakpoint (process);
983 if (debug_threads && the_low_target.get_pc != NULL)
985 fprintf (stderr, " ");
986 (*the_low_target.get_pc) ();
989 /* If we have pending signals, consume one unless we are trying to reinsert
991 if (process->pending_signals != NULL && process->bp_reinsert == 0)
993 struct pending_signals **p_sig;
995 p_sig = &process->pending_signals;
996 while ((*p_sig)->prev != NULL)
997 p_sig = &(*p_sig)->prev;
999 signal = (*p_sig)->signal;
1000 if ((*p_sig)->info.si_signo != 0)
1001 ptrace (PTRACE_SETSIGINFO, process->lwpid, 0, &(*p_sig)->info);
1007 regcache_invalidate_one ((struct inferior_list_entry *)
1008 get_process_thread (process));
1010 process->stopped = 0;
1011 process->stepping = step;
1012 ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, process->lwpid, 0, signal);
1014 current_inferior = saved_inferior;
1016 perror_with_name ("ptrace");
1019 static struct thread_resume *resume_ptr;
1021 /* This function is called once per thread. We look up the thread
1022 in RESUME_PTR, and mark the thread with a pointer to the appropriate
1025 This algorithm is O(threads * resume elements), but resume elements
1026 is small (and will remain small at least until GDB supports thread
1029 linux_set_resume_request (struct inferior_list_entry *entry)
1031 struct process_info *process;
1032 struct thread_info *thread;
1035 thread = (struct thread_info *) entry;
1036 process = get_thread_process (thread);
1039 while (resume_ptr[ndx].thread != -1 && resume_ptr[ndx].thread != entry->id)
1042 process->resume = &resume_ptr[ndx];
1045 /* This function is called once per thread. We check the thread's resume
1046 request, which will tell us whether to resume, step, or leave the thread
1047 stopped; and what signal, if any, it should be sent. For threads which
1048 we aren't explicitly told otherwise, we preserve the stepping flag; this
1049 is used for stepping over gdbserver-placed breakpoints. */
1052 linux_continue_one_thread (struct inferior_list_entry *entry)
1054 struct process_info *process;
1055 struct thread_info *thread;
1058 thread = (struct thread_info *) entry;
1059 process = get_thread_process (thread);
1061 if (process->resume->leave_stopped)
1064 if (process->resume->thread == -1)
1065 step = process->stepping || process->resume->step;
1067 step = process->resume->step;
1069 linux_resume_one_process (&process->head, step, process->resume->sig, NULL);
1071 process->resume = NULL;
1074 /* This function is called once per thread. We check the thread's resume
1075 request, which will tell us whether to resume, step, or leave the thread
1076 stopped; and what signal, if any, it should be sent. We queue any needed
1077 signals, since we won't actually resume. We already have a pending event
1078 to report, so we don't need to preserve any step requests; they should
1079 be re-issued if necessary. */
1082 linux_queue_one_thread (struct inferior_list_entry *entry)
1084 struct process_info *process;
1085 struct thread_info *thread;
1087 thread = (struct thread_info *) entry;
1088 process = get_thread_process (thread);
1090 if (process->resume->leave_stopped)
1093 /* If we have a new signal, enqueue the signal. */
1094 if (process->resume->sig != 0)
1096 struct pending_signals *p_sig;
1097 p_sig = malloc (sizeof (*p_sig));
1098 p_sig->prev = process->pending_signals;
1099 p_sig->signal = process->resume->sig;
1100 memset (&p_sig->info, 0, sizeof (siginfo_t));
1102 /* If this is the same signal we were previously stopped by,
1103 make sure to queue its siginfo. We can ignore the return
1104 value of ptrace; if it fails, we'll skip
1105 PTRACE_SETSIGINFO. */
1106 if (WIFSTOPPED (process->last_status)
1107 && WSTOPSIG (process->last_status) == process->resume->sig)
1108 ptrace (PTRACE_GETSIGINFO, process->lwpid, 0, &p_sig->info);
1110 process->pending_signals = p_sig;
1113 process->resume = NULL;
1116 /* Set DUMMY if this process has an interesting status pending. */
1118 resume_status_pending_p (struct inferior_list_entry *entry, void *flag_p)
1120 struct process_info *process = (struct process_info *) entry;
1122 /* Processes which will not be resumed are not interesting, because
1123 we might not wait for them next time through linux_wait. */
1124 if (process->resume->leave_stopped)
1127 /* If this thread has a removed breakpoint, we won't have any
1128 events to report later, so check now. check_removed_breakpoint
1129 may clear status_pending_p. We avoid calling check_removed_breakpoint
1130 for any thread that we are not otherwise going to resume - this
1131 lets us preserve stopped status when two threads hit a breakpoint.
1132 GDB removes the breakpoint to single-step a particular thread
1133 past it, then re-inserts it and resumes all threads. We want
1134 to report the second thread without resuming it in the interim. */
1135 if (process->status_pending_p)
1136 check_removed_breakpoint (process);
1138 if (process->status_pending_p)
1139 * (int *) flag_p = 1;
1145 linux_resume (struct thread_resume *resume_info)
1149 /* Yes, the use of a global here is rather ugly. */
1150 resume_ptr = resume_info;
1152 for_each_inferior (&all_threads, linux_set_resume_request);
1154 /* If there is a thread which would otherwise be resumed, which
1155 has a pending status, then don't resume any threads - we can just
1156 report the pending status. Make sure to queue any signals
1157 that would otherwise be sent. */
1159 find_inferior (&all_processes, resume_status_pending_p, &pending_flag);
1164 fprintf (stderr, "Not resuming, pending status\n");
1166 fprintf (stderr, "Resuming, no pending status\n");
1170 for_each_inferior (&all_threads, linux_queue_one_thread);
1175 for_each_inferior (&all_threads, linux_continue_one_thread);
1179 #ifdef HAVE_LINUX_USRREGS
1182 register_addr (int regnum)
1186 if (regnum < 0 || regnum >= the_low_target.num_regs)
1187 error ("Invalid register number %d.", regnum);
1189 addr = the_low_target.regmap[regnum];
1194 /* Fetch one register. */
1196 fetch_register (int regno)
1202 if (regno >= the_low_target.num_regs)
1204 if ((*the_low_target.cannot_fetch_register) (regno))
1207 regaddr = register_addr (regno);
1210 size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1)
1211 & - sizeof (PTRACE_XFER_TYPE);
1212 buf = alloca (size);
1213 for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE))
1216 *(PTRACE_XFER_TYPE *) (buf + i) =
1217 ptrace (PTRACE_PEEKUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, 0);
1218 regaddr += sizeof (PTRACE_XFER_TYPE);
1221 /* Warning, not error, in case we are attached; sometimes the
1222 kernel doesn't let us at the registers. */
1223 char *err = strerror (errno);
1224 char *msg = alloca (strlen (err) + 128);
1225 sprintf (msg, "reading register %d: %s", regno, err);
1230 if (the_low_target.left_pad_xfer
1231 && register_size (regno) < sizeof (PTRACE_XFER_TYPE))
1232 supply_register (regno, (buf + sizeof (PTRACE_XFER_TYPE)
1233 - register_size (regno)));
1235 supply_register (regno, buf);
1240 /* Fetch all registers, or just one, from the child process. */
1242 usr_fetch_inferior_registers (int regno)
1244 if (regno == -1 || regno == 0)
1245 for (regno = 0; regno < the_low_target.num_regs; regno++)
1246 fetch_register (regno);
1248 fetch_register (regno);
1251 /* Store our register values back into the inferior.
1252 If REGNO is -1, do this for all registers.
1253 Otherwise, REGNO specifies which register (so we can save time). */
1255 usr_store_inferior_registers (int regno)
1263 if (regno >= the_low_target.num_regs)
1266 if ((*the_low_target.cannot_store_register) (regno) == 1)
1269 regaddr = register_addr (regno);
1273 size = (register_size (regno) + sizeof (PTRACE_XFER_TYPE) - 1)
1274 & - sizeof (PTRACE_XFER_TYPE);
1275 buf = alloca (size);
1276 memset (buf, 0, size);
1277 if (the_low_target.left_pad_xfer
1278 && register_size (regno) < sizeof (PTRACE_XFER_TYPE))
1279 collect_register (regno, (buf + sizeof (PTRACE_XFER_TYPE)
1280 - register_size (regno)));
1282 collect_register (regno, buf);
1283 for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE))
1286 ptrace (PTRACE_POKEUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
1287 *(PTRACE_XFER_TYPE *) (buf + i));
1290 if ((*the_low_target.cannot_store_register) (regno) == 0)
1292 char *err = strerror (errno);
1293 char *msg = alloca (strlen (err) + 128);
1294 sprintf (msg, "writing register %d: %s",
1300 regaddr += sizeof (PTRACE_XFER_TYPE);
1304 for (regno = 0; regno < the_low_target.num_regs; regno++)
1305 usr_store_inferior_registers (regno);
1307 #endif /* HAVE_LINUX_USRREGS */
1311 #ifdef HAVE_LINUX_REGSETS
1314 regsets_fetch_inferior_registers ()
1316 struct regset_info *regset;
1317 int saw_general_regs = 0;
1319 regset = target_regsets;
1321 while (regset->size >= 0)
1326 if (regset->size == 0)
1332 buf = malloc (regset->size);
1333 res = ptrace (regset->get_request, inferior_pid, 0, buf);
1338 /* If we get EIO on the first regset, do not try regsets again.
1339 If we get EIO on a later regset, disable that regset. */
1340 if (regset == target_regsets)
1354 sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%ld",
1359 else if (regset->type == GENERAL_REGS)
1360 saw_general_regs = 1;
1361 regset->store_function (buf);
1364 if (saw_general_regs)
1371 regsets_store_inferior_registers ()
1373 struct regset_info *regset;
1374 int saw_general_regs = 0;
1376 regset = target_regsets;
1378 while (regset->size >= 0)
1383 if (regset->size == 0)
1389 buf = malloc (regset->size);
1391 /* First fill the buffer with the current register set contents,
1392 in case there are any items in the kernel's regset that are
1393 not in gdbserver's regcache. */
1394 res = ptrace (regset->get_request, inferior_pid, 0, buf);
1398 /* Then overlay our cached registers on that. */
1399 regset->fill_function (buf);
1401 /* Only now do we write the register set. */
1402 res = ptrace (regset->set_request, inferior_pid, 0, buf);
1409 /* If we get EIO on the first regset, do not try regsets again.
1410 If we get EIO on a later regset, disable that regset. */
1411 if (regset == target_regsets)
1424 perror ("Warning: ptrace(regsets_store_inferior_registers)");
1427 else if (regset->type == GENERAL_REGS)
1428 saw_general_regs = 1;
1432 if (saw_general_regs)
1439 #endif /* HAVE_LINUX_REGSETS */
1443 linux_fetch_registers (int regno)
1445 #ifdef HAVE_LINUX_REGSETS
1448 if (regsets_fetch_inferior_registers () == 0)
1452 #ifdef HAVE_LINUX_USRREGS
1453 usr_fetch_inferior_registers (regno);
1458 linux_store_registers (int regno)
1460 #ifdef HAVE_LINUX_REGSETS
1463 if (regsets_store_inferior_registers () == 0)
1467 #ifdef HAVE_LINUX_USRREGS
1468 usr_store_inferior_registers (regno);
1473 /* Copy LEN bytes from inferior's memory starting at MEMADDR
1474 to debugger memory starting at MYADDR. */
1477 linux_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len)
1480 /* Round starting address down to longword boundary. */
1481 register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
1482 /* Round ending address up; get number of longwords that makes. */
1484 = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
1485 / sizeof (PTRACE_XFER_TYPE);
1486 /* Allocate buffer of that many longwords. */
1487 register PTRACE_XFER_TYPE *buffer
1488 = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
1490 /* Read all the longwords */
1491 for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
1494 buffer[i] = ptrace (PTRACE_PEEKTEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, 0);
1499 /* Copy appropriate bytes out of the buffer. */
1500 memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), len);
1505 /* Copy LEN bytes of data from debugger memory at MYADDR
1506 to inferior's memory at MEMADDR.
1507 On failure (cannot write the inferior)
1508 returns the value of errno. */
1511 linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len)
1514 /* Round starting address down to longword boundary. */
1515 register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
1516 /* Round ending address up; get number of longwords that makes. */
1518 = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE);
1519 /* Allocate buffer of that many longwords. */
1520 register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
1525 fprintf (stderr, "Writing %02x to %08lx\n", (unsigned)myaddr[0], (long)memaddr);
1528 /* Fill start and end extra bytes of buffer with existing memory data. */
1530 buffer[0] = ptrace (PTRACE_PEEKTEXT, inferior_pid,
1531 (PTRACE_ARG3_TYPE) addr, 0);
1536 = ptrace (PTRACE_PEEKTEXT, inferior_pid,
1537 (PTRACE_ARG3_TYPE) (addr + (count - 1)
1538 * sizeof (PTRACE_XFER_TYPE)),
1542 /* Copy data to be written over corresponding part of buffer */
1544 memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), myaddr, len);
1546 /* Write the entire buffer. */
1548 for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
1551 ptrace (PTRACE_POKETEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, buffer[i]);
1560 linux_look_up_symbols (void)
1562 #ifdef USE_THREAD_DB
1566 using_threads = thread_db_init ();
1571 linux_request_interrupt (void)
1573 extern unsigned long signal_pid;
1575 if (cont_thread != 0 && cont_thread != -1)
1577 struct process_info *process;
1579 process = get_thread_process (current_inferior);
1580 kill_lwp (process->lwpid, SIGINT);
1583 kill_lwp (signal_pid, SIGINT);
1586 /* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET
1587 to debugger memory starting at MYADDR. */
1590 linux_read_auxv (CORE_ADDR offset, unsigned char *myaddr, unsigned int len)
1592 char filename[PATH_MAX];
1595 snprintf (filename, sizeof filename, "/proc/%ld/auxv", inferior_pid);
1597 fd = open (filename, O_RDONLY);
1601 if (offset != (CORE_ADDR) 0
1602 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
1605 n = read (fd, myaddr, len);
1612 /* These watchpoint related wrapper functions simply pass on the function call
1613 if the target has registered a corresponding function. */
1616 linux_insert_watchpoint (char type, CORE_ADDR addr, int len)
1618 if (the_low_target.insert_watchpoint != NULL)
1619 return the_low_target.insert_watchpoint (type, addr, len);
1621 /* Unsupported (see target.h). */
1626 linux_remove_watchpoint (char type, CORE_ADDR addr, int len)
1628 if (the_low_target.remove_watchpoint != NULL)
1629 return the_low_target.remove_watchpoint (type, addr, len);
1631 /* Unsupported (see target.h). */
1636 linux_stopped_by_watchpoint (void)
1638 if (the_low_target.stopped_by_watchpoint != NULL)
1639 return the_low_target.stopped_by_watchpoint ();
1645 linux_stopped_data_address (void)
1647 if (the_low_target.stopped_data_address != NULL)
1648 return the_low_target.stopped_data_address ();
1653 #if defined(__UCLIBC__) && defined(HAS_NOMMU)
1654 #if defined(__mcoldfire__)
1655 /* These should really be defined in the kernel's ptrace.h header. */
1656 #define PT_TEXT_ADDR 49*4
1657 #define PT_DATA_ADDR 50*4
1658 #define PT_TEXT_END_ADDR 51*4
1661 /* Under uClinux, programs are loaded at non-zero offsets, which we need
1662 to tell gdb about. */
1665 linux_read_offsets (CORE_ADDR *text_p, CORE_ADDR *data_p)
1667 #if defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) && defined(PT_TEXT_END_ADDR)
1668 unsigned long text, text_end, data;
1669 int pid = get_thread_process (current_inferior)->head.id;
1673 text = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_ADDR, 0);
1674 text_end = ptrace (PTRACE_PEEKUSER, pid, (long)PT_TEXT_END_ADDR, 0);
1675 data = ptrace (PTRACE_PEEKUSER, pid, (long)PT_DATA_ADDR, 0);
1679 /* Both text and data offsets produced at compile-time (and so
1680 used by gdb) are relative to the beginning of the program,
1681 with the data segment immediately following the text segment.
1682 However, the actual runtime layout in memory may put the data
1683 somewhere else, so when we send gdb a data base-address, we
1684 use the real data base address and subtract the compile-time
1685 data base-address from it (which is just the length of the
1686 text segment). BSS immediately follows data in both
1689 *data_p = data - (text_end - text);
1699 linux_arch_string (void)
1701 return the_low_target.arch_string;
1704 static struct target_ops linux_target_ops = {
1705 linux_create_inferior,
1713 linux_fetch_registers,
1714 linux_store_registers,
1717 linux_look_up_symbols,
1718 linux_request_interrupt,
1720 linux_insert_watchpoint,
1721 linux_remove_watchpoint,
1722 linux_stopped_by_watchpoint,
1723 linux_stopped_data_address,
1724 #if defined(__UCLIBC__) && defined(HAS_NOMMU)
1729 #ifdef USE_THREAD_DB
1730 thread_db_get_tls_address,
1738 linux_init_signals ()
1740 /* FIXME drow/2002-06-09: As above, we should check with LinuxThreads
1741 to find what the cancel signal actually is. */
1742 signal (__SIGRTMIN+1, SIG_IGN);
1746 initialize_low (void)
1749 set_target_ops (&linux_target_ops);
1750 set_breakpoint_data (the_low_target.breakpoint,
1751 the_low_target.breakpoint_len);
1753 linux_init_signals ();