/* Multi-threaded debugging support for GNU/Linux (LWP layer).
- Copyright 2000, 2001 Free Software Foundation, Inc.
+ Copyright 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
This file is part of GDB.
#include "defs.h"
#include "gdb_assert.h"
+#include "gdb_string.h"
#include <errno.h>
#include <signal.h>
+#ifdef HAVE_TKILL_SYSCALL
+#include <unistd.h>
+#include <sys/syscall.h>
+#endif
#include <sys/ptrace.h>
#include "gdb_wait.h"
#include "gdbcmd.h"
static int debug_lin_lwp;
-extern const char *strsignal (int sig);
+extern char *strsignal (int sig);
+
+#include "linux-nat.h"
/* On GNU/Linux there are no real LWP's. The closest thing to LWP's
are processes sharing the same VM space. A multi-threaded process
threads will run out of processes, even if the threads exit,
because the "zombies" stay around. */
-/* Structure describing a LWP. */
-struct lwp_info
-{
- /* The process id of the LWP. This is a combination of the LWP id
- and overall process id. */
- ptid_t ptid;
-
- /* Non-zero if this LWP is cloned. In this context "cloned" means
- that the LWP is reporting to its parent using a signal other than
- SIGCHLD. */
- int cloned;
-
- /* Non-zero if we sent this LWP a SIGSTOP (but the LWP didn't report
- it back yet). */
- int signalled;
-
- /* Non-zero if this LWP is stopped. */
- int stopped;
-
- /* Non-zero if this LWP will be/has been resumed. Note that an LWP
- can be marked both as stopped and resumed at the same time. This
- happens if we try to resume an LWP that has a wait status
- pending. We shouldn't let the LWP run until that wait status has
- been processed, but we should not report that wait status if GDB
- didn't try to let the LWP run. */
- int resumed;
-
- /* If non-zero, a pending wait status. */
- int status;
-
- /* Non-zero if we were stepping this LWP. */
- int step;
-
- /* Next LWP in list. */
- struct lwp_info *next;
-};
-
/* List of known LWPs. */
static struct lwp_info *lwp_list;
/* Prototypes for local functions. */
static int stop_wait_callback (struct lwp_info *lp, void *data);
+static int lin_lwp_thread_alive (ptid_t ptid);
\f
/* Convert wait status STATUS to a string. Used for printing debug
messages only. */
snprintf (buf, sizeof (buf), "%s (terminated)",
strsignal (WSTOPSIG (status)));
else
- snprintf (buf, sizeof (buf), "%d (exited)",
- WEXITSTATUS (status));
+ snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status));
return buf;
}
}
\f
-/* Implementation of the PREPARE_TO_PROCEED hook for the GNU/Linux LWP
- layer.
-
- Note that this implementation is potentially redundant now that
- default_prepare_to_proceed() has been added.
-
- FIXME This may not support switching threads after Ctrl-C
- correctly. The default implementation does support this. */
-
-int
-lin_lwp_prepare_to_proceed (void)
-{
- if (! ptid_equal (trap_ptid, null_ptid)
- && ! ptid_equal (inferior_ptid, trap_ptid))
- {
- /* Switched over from TRAP_PID. */
- CORE_ADDR stop_pc = read_pc ();
- CORE_ADDR trap_pc;
-
- /* Avoid switching where it wouldn't do any good, i.e. if both
- threads are at the same breakpoint. */
- trap_pc = read_pc_pid (trap_ptid);
- if (trap_pc != stop_pc && breakpoint_here_p (trap_pc))
- {
- /* User hasn't deleted the breakpoint. Return non-zero, and
- switch back to TRAP_PID. */
- inferior_ptid = trap_ptid;
-
- /* FIXME: Is this stuff really necessary? */
- flush_cached_frames ();
- registers_changed ();
-
- return 1;
- }
- }
-
- return 0;
-}
-\f
-
#if 0
static void
lin_lwp_open (char *args, int from_tty)
/* Make sure SIGCHLD is blocked. We don't want SIGCHLD events
to interrupt either the ptrace() or waitpid() calls below. */
- if (! sigismember (&blocked_mask, SIGCHLD))
+ if (!sigismember (&blocked_mask, SIGCHLD))
{
sigaddset (&blocked_mask, SIGCHLD);
sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
error ("Can't attach %s: %s", target_pid_to_str (ptid),
safe_strerror (errno));
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
+ target_pid_to_str (ptid));
+
pid = waitpid (GET_LWP (ptid), &status, 0);
if (pid == -1 && errno == ECHILD)
{
gdb_assert (pid == GET_LWP (ptid)
&& WIFSTOPPED (status) && WSTOPSIG (status));
+ child_post_attach (pid);
+
lp->stopped = 1;
+
+ if (debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "LLAL: waitpid %s received %s\n",
+ target_pid_to_str (ptid),
+ status_to_str (status));
+ }
}
else
{
/* We assume that the LWP representing the original process
- is already stopped. Mark it as stopped in the data structure
- that the lin-lwp layer uses to keep track of threads. Note
- that this won't have already been done since the main thread
- will have, we assume, been stopped by an attach from a
- different layer. */
+ is already stopped. Mark it as stopped in the data structure
+ that the lin-lwp layer uses to keep track of threads. Note
+ that this won't have already been done since the main thread
+ will have, we assume, been stopped by an attach from a
+ different layer. */
lp->stopped = 1;
}
}
/* Fake the SIGSTOP that core GDB expects. */
lp->status = W_STOPCODE (SIGSTOP);
lp->resumed = 1;
+ if (debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "LLA: waitpid %ld, faking SIGSTOP\n", (long) pid);
+ }
}
static int
gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
if (debug_lin_lwp && lp->status)
- fprintf_unfiltered (gdb_stdlog, "Pending %s for LWP %ld on detach.\n",
- strsignal (WSTOPSIG (lp->status)), GET_LWP (lp->ptid));
+ fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
+ strsignal (WSTOPSIG (lp->status)),
+ target_pid_to_str (lp->ptid));
while (lp->signalled && lp->stopped)
{
+ errno = 0;
if (ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0,
WSTOPSIG (lp->status)) < 0)
error ("Can't continue %s: %s", target_pid_to_str (lp->ptid),
safe_strerror (errno));
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "DC: PTRACE_CONTINUE (%s, 0, %s) (OK)\n",
+ target_pid_to_str (lp->ptid),
+ status_to_str (lp->status));
+
lp->stopped = 0;
lp->signalled = 0;
lp->status = 0;
- stop_wait_callback (lp, NULL);
+ /* FIXME drow/2003-08-26: There was a call to stop_wait_callback
+ here. But since lp->signalled was cleared above,
+ stop_wait_callback didn't do anything; the process was left
+ running. Shouldn't we be waiting for it to stop?
+ I've removed the call, since stop_wait_callback now does do
+ something when called with lp->signalled == 0. */
gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
}
overall process id just yet. */
if (GET_LWP (lp->ptid) != GET_PID (lp->ptid))
{
+ errno = 0;
if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0,
WSTOPSIG (lp->status)) < 0)
error ("Can't detach %s: %s", target_pid_to_str (lp->ptid),
safe_strerror (errno));
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "PTRACE_DETACH (%s, %s, 0) (OK)\n",
+ target_pid_to_str (lp->ptid),
+ strsignal (WSTOPSIG (lp->status)));
+
delete_lwp (lp->ptid);
}
}
\f
-struct private_thread_info
-{
- int lwpid;
-};
-
-/* Return non-zero if TP corresponds to the LWP specified by DATA
- (which is assumed to be a pointer to a `struct lwp_info'. */
-
-static int
-find_lwp_callback (struct thread_info *tp, void *data)
-{
- struct lwp_info *lp = data;
-
- if (tp->private->lwpid == GET_LWP (lp->ptid))
- return 1;
-
- return 0;
-}
-
/* Resume LP. */
static int
{
struct thread_info *tp;
-#if 0
- /* FIXME: kettenis/2000-08-26: This should really be handled
- properly by core GDB. */
-
- tp = find_thread_pid (lp->ptid);
- if (tp == NULL)
- tp = iterate_over_threads (find_lwp_callback, lp);
- gdb_assert (tp);
-
- /* If we were previously stepping the thread, and now continue
- the thread we must invalidate the stepping range. However,
- if there is a step_resume breakpoint for this thread, we must
- preserve the stepping range to make it possible to continue
- stepping once we hit it. */
- if (tp->step_range_end && tp->step_resume_breakpoint == NULL)
- {
- gdb_assert (lp->step);
- tp->step_range_start = tp->step_range_end = 0;
- }
-#endif
-
child_resume (pid_to_ptid (GET_LWP (lp->ptid)), 0, TARGET_SIGNAL_0);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "RC: PTRACE_CONT %s, 0, 0 (resume sibling)\n",
+ target_pid_to_str (lp->ptid));
lp->stopped = 0;
lp->step = 0;
}
struct lwp_info *lp;
int resume_all;
- /* Apparently the interpretation of PID is dependent on STEP: If
- STEP is non-zero, a specific PID means `step only this process
- id'. But if STEP is zero, then PID means `continue *all*
- processes, but give the signal only to this one'. */
- resume_all = (PIDGET (ptid) == -1) || !step;
+ /* A specific PTID means `step only this process id'. */
+ resume_all = (PIDGET (ptid) == -1);
if (resume_all)
iterate_over_lwps (resume_set_callback, NULL);
if (lp->status)
{
/* FIXME: What should we do if we are supposed to continue
- this thread with a signal? */
+ this thread with a signal? */
gdb_assert (signo == TARGET_SIGNAL_0);
return;
}
/* Mark LWP as not stopped to prevent it from being continued by
- resume_callback. */
+ resume_callback. */
lp->stopped = 0;
}
iterate_over_lwps (resume_callback, NULL);
child_resume (ptid, step, signo);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLR: %s %s, %s (resume event thread)\n",
+ step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
+ target_pid_to_str (ptid),
+ signo ? strsignal (signo) : "0");
}
\f
+/* Issue kill to specified lwp. */
+
+static int tkill_failed;
+
+static int
+kill_lwp (int lwpid, int signo)
+{
+ errno = 0;
+
+/* Use tkill, if possible, in case we are using nptl threads. If tkill
+ fails, then we are not using nptl threads and we should be using kill. */
+
+#ifdef HAVE_TKILL_SYSCALL
+ if (!tkill_failed)
+ {
+ int ret = syscall (__NR_tkill, lwpid, signo);
+ if (errno != ENOSYS)
+ return ret;
+ errno = 0;
+ tkill_failed = 1;
+ }
+#endif
+
+ return kill (lwpid, signo);
+}
+
+/* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
+ exited. */
+
+static int
+wait_lwp (struct lwp_info *lp)
+{
+ pid_t pid;
+ int status;
+ int thread_dead = 0;
+
+ gdb_assert (!lp->stopped);
+ gdb_assert (lp->status == 0);
+
+ pid = waitpid (GET_LWP (lp->ptid), &status, 0);
+ if (pid == -1 && errno == ECHILD)
+ {
+ pid = waitpid (GET_LWP (lp->ptid), &status, __WCLONE);
+ if (pid == -1 && errno == ECHILD)
+ {
+ /* The thread has previously exited. We need to delete it now
+ because in the case of NPTL threads, there won't be an
+ exit event unless it is the main thread. */
+ thread_dead = 1;
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
+ target_pid_to_str (lp->ptid));
+ }
+ }
+
+ if (!thread_dead)
+ {
+ gdb_assert (pid == GET_LWP (lp->ptid));
+
+ if (debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "WL: waitpid %s received %s\n",
+ target_pid_to_str (lp->ptid),
+ status_to_str (status));
+ }
+ }
+
+ /* Check if the thread has exited. */
+ if (WIFEXITED (status) || WIFSIGNALED (status))
+ {
+ thread_dead = 1;
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
+ target_pid_to_str (lp->ptid));
+ }
+
+ if (thread_dead)
+ {
+ if (in_thread_list (lp->ptid))
+ {
+ /* Core GDB cannot deal with us deleting the current thread. */
+ if (!ptid_equal (lp->ptid, inferior_ptid))
+ delete_thread (lp->ptid);
+ printf_unfiltered ("[%s exited]\n",
+ target_pid_to_str (lp->ptid));
+ }
+
+ delete_lwp (lp->ptid);
+ return 0;
+ }
+
+ gdb_assert (WIFSTOPPED (status));
+
+ return status;
+}
+
/* Send a SIGSTOP to LP. */
static int
stop_callback (struct lwp_info *lp, void *data)
{
- if (! lp->stopped && ! lp->signalled)
+ if (!lp->stopped && !lp->signalled)
{
int ret;
- ret = kill (GET_LWP (lp->ptid), SIGSTOP);
- gdb_assert (ret == 0);
+ if (debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "SC: kill %s **<SIGSTOP>**\n",
+ target_pid_to_str (lp->ptid));
+ }
+ errno = 0;
+ ret = kill_lwp (GET_LWP (lp->ptid), SIGSTOP);
+ if (debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "SC: lwp kill %d %s\n",
+ ret,
+ errno ? safe_strerror (errno) : "ERRNO-OK");
+ }
lp->signalled = 1;
gdb_assert (lp->status == 0);
{
sigset_t *flush_mask = data;
- if (! lp->stopped && lp->signalled)
+ if (!lp->stopped)
{
- pid_t pid;
int status;
- gdb_assert (lp->status == 0);
-
- pid = waitpid (GET_LWP (lp->ptid), &status, lp->cloned ? __WCLONE : 0);
- if (pid == -1 && errno == ECHILD)
- /* OK, the proccess has disappeared. We'll catch the actual
- exit event in lin_lwp_wait. */
+ status = wait_lwp (lp);
+ if (status == 0)
return 0;
- gdb_assert (pid == GET_LWP (lp->ptid));
-
- if (WIFEXITED (status) || WIFSIGNALED (status))
+ /* Ignore any signals in FLUSH_MASK. */
+ if (flush_mask && sigismember (flush_mask, WSTOPSIG (status)))
{
- gdb_assert (num_lwps > 1);
-
- if (in_thread_list (lp->ptid))
+ if (!lp->signalled)
{
- /* Core GDB cannot deal with us deleting the current
- thread. */
- if (!ptid_equal (lp->ptid, inferior_ptid))
- delete_thread (lp->ptid);
- printf_unfiltered ("[%s exited]\n",
- target_pid_to_str (lp->ptid));
+ lp->stopped = 1;
+ return 0;
}
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "%s exited.\n", target_pid_to_str (lp->ptid));
-
- delete_lwp (lp->ptid);
- return 0;
- }
-
- gdb_assert (WIFSTOPPED (status));
- /* Ignore any signals in FLUSH_MASK. */
- if (flush_mask && sigismember (flush_mask, WSTOPSIG (status)))
- {
+ errno = 0;
ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "PTRACE_CONT %s, 0, 0 (%s)\n",
+ target_pid_to_str (lp->ptid),
+ errno ? safe_strerror (errno) : "OK");
+
return stop_wait_callback (lp, flush_mask);
}
if (WSTOPSIG (status) == SIGTRAP)
{
/* If a LWP other than the LWP that we're reporting an
- event for has hit a GDB breakpoint (as opposed to
- some random trap signal), then just arrange for it to
- hit it again later. We don't keep the SIGTRAP status
- and don't forward the SIGTRAP signal to the LWP. We
- will handle the current event, eventually we will
- resume all LWPs, and this one will get its breakpoint
- trap again.
-
- If we do not do this, then we run the risk that the
- user will delete or disable the breakpoint, but the
- thread will have already tripped on it. */
+ event for has hit a GDB breakpoint (as opposed to
+ some random trap signal), then just arrange for it to
+ hit it again later. We don't keep the SIGTRAP status
+ and don't forward the SIGTRAP signal to the LWP. We
+ will handle the current event, eventually we will
+ resume all LWPs, and this one will get its breakpoint
+ trap again.
+
+ If we do not do this, then we run the risk that the
+ user will delete or disable the breakpoint, but the
+ thread will have already tripped on it. */
/* Now resume this LWP and get the SIGSTOP event. */
+ errno = 0;
ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
if (debug_lin_lwp)
{
- fprintf_unfiltered (gdb_stderr,
- "SWC: Candidate SIGTRAP event in %ld\n",
- GET_LWP (lp->ptid));
+ fprintf_unfiltered (gdb_stdlog,
+ "PTRACE_CONT %s, 0, 0 (%s)\n",
+ target_pid_to_str (lp->ptid),
+ errno ? safe_strerror (errno) : "OK");
+
+ fprintf_unfiltered (gdb_stdlog,
+ "SWC: Candidate SIGTRAP event in %s\n",
+ target_pid_to_str (lp->ptid));
}
/* Hold the SIGTRAP for handling by lin_lwp_wait. */
stop_wait_callback (lp, data);
/* If there's another event, throw it back into the queue. */
if (lp->status)
- kill (GET_LWP (lp->ptid), WSTOPSIG (lp->status));
+ {
+ if (debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "SWC: kill %s, %s\n",
+ target_pid_to_str (lp->ptid),
+ status_to_str ((int) status));
+ }
+ kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (lp->status));
+ }
/* Save the sigtrap event. */
lp->status = status;
return 0;
else
{
/* The thread was stopped with a signal other than
- SIGSTOP, and didn't accidentally trip a breakpoint. */
+ SIGSTOP, and didn't accidentally trip a breakpoint. */
if (debug_lin_lwp)
{
- fprintf_unfiltered (gdb_stderr,
- "SWC: Pending event %d in %ld\n",
- WSTOPSIG (status), GET_LWP (lp->ptid));
+ fprintf_unfiltered (gdb_stdlog,
+ "SWC: Pending event %s in %s\n",
+ status_to_str ((int) status),
+ target_pid_to_str (lp->ptid));
}
/* Now resume this LWP and get the SIGSTOP event. */
+ errno = 0;
ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "SWC: PTRACE_CONT %s, 0, 0 (%s)\n",
+ target_pid_to_str (lp->ptid),
+ errno ? safe_strerror (errno) : "OK");
/* Hold this event/waitstatus while we check to see if
- there are any more (we still want to get that SIGSTOP). */
+ there are any more (we still want to get that SIGSTOP). */
stop_wait_callback (lp, data);
/* If the lp->status field is still empty, use it to hold
- this event. If not, then this event must be returned
- to the event queue of the LWP. */
+ this event. If not, then this event must be returned
+ to the event queue of the LWP. */
if (lp->status == 0)
lp->status = status;
else
- kill (GET_LWP (lp->ptid), WSTOPSIG (status));
+ {
+ if (debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "SWC: kill %s, %s\n",
+ target_pid_to_str (lp->ptid),
+ status_to_str ((int) status));
+ }
+ kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (status));
+ }
return 0;
}
}
else
{
/* We caught the SIGSTOP that we intended to catch, so
- there's no SIGSTOP pending. */
+ there's no SIGSTOP pending. */
lp->stopped = 1;
lp->signalled = 0;
}
return 0;
}
+/* Check whether PID has any pending signals in FLUSH_MASK. If so set
+ the appropriate bits in PENDING, and return 1 - otherwise return 0. */
+
+static int
+lin_lwp_has_pending (int pid, sigset_t *pending, sigset_t *flush_mask)
+{
+ sigset_t blocked, ignored;
+ int i;
+
+ linux_proc_pending_signals (pid, pending, &blocked, &ignored);
+
+ if (!flush_mask)
+ return 0;
+
+ for (i = 1; i < NSIG; i++)
+ if (sigismember (pending, i))
+ if (!sigismember (flush_mask, i)
+ || sigismember (&blocked, i)
+ || sigismember (&ignored, i))
+ sigdelset (pending, i);
+
+ if (sigisemptyset (pending))
+ return 0;
+
+ return 1;
+}
+
+/* DATA is interpreted as a mask of signals to flush. If LP has
+ signals pending, and they are all in the flush mask, then arrange
+ to flush them. LP should be stopped, as should all other threads
+ it might share a signal queue with. */
+
+static int
+flush_callback (struct lwp_info *lp, void *data)
+{
+ sigset_t *flush_mask = data;
+ sigset_t pending, intersection, blocked, ignored;
+ int pid, status;
+
+ /* Normally, when an LWP exits, it is removed from the LWP list. The
+ last LWP isn't removed till later, however. So if there is only
+ one LWP on the list, make sure it's alive. */
+ if (lwp_list == lp && lp->next == NULL)
+ if (!lin_lwp_thread_alive (lp->ptid))
+ return 0;
+
+ /* Just because the LWP is stopped doesn't mean that new signals
+ can't arrive from outside, so this function must be careful of
+ race conditions. However, because all threads are stopped, we
+ can assume that the pending mask will not shrink unless we resume
+ the LWP, and that it will then get another signal. We can't
+ control which one, however. */
+
+ if (lp->status)
+ {
+ if (debug_lin_lwp)
+ printf_unfiltered ("FC: LP has pending status %06x\n", lp->status);
+ if (WIFSTOPPED (lp->status) && sigismember (flush_mask, WSTOPSIG (lp->status)))
+ lp->status = 0;
+ }
+
+ while (lin_lwp_has_pending (GET_LWP (lp->ptid), &pending, flush_mask))
+ {
+ int ret;
+
+ errno = 0;
+ ret = ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stderr,
+ "FC: Sent PTRACE_CONT, ret %d %d\n", ret, errno);
+
+ lp->stopped = 0;
+ stop_wait_callback (lp, flush_mask);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stderr,
+ "FC: Wait finished; saved status is %d\n",
+ lp->status);
+ }
+
+ return 0;
+}
+
/* Return non-zero if LP has a wait status pending. */
static int
static int
running_callback (struct lwp_info *lp, void *data)
{
- return (lp->stopped == 0);
+ return (lp->stopped == 0 || (lp->status != 0 && lp->resumed));
}
/* Count the LWP's that have had events. */
tripped on it. */
if (lp->status != 0
- && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP
- && breakpoint_inserted_here_p (read_pc_pid (lp->ptid) -
+ && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP
+ && breakpoint_inserted_here_p (read_pc_pid (lp->ptid) -
DECR_PC_AFTER_BREAK))
{
if (debug_lin_lwp)
fprintf_unfiltered (gdb_stdlog,
- "Push back breakpoint for LWP %ld\n",
- GET_LWP (lp->ptid));
+ "CBC: Push back breakpoint for %s\n",
+ target_pid_to_str (lp->ptid));
/* Back up the PC if necessary. */
if (DECR_PC_AFTER_BREAK)
{
if (debug_lin_lwp)
fprintf_unfiltered (gdb_stdlog,
- "Select single-step LWP %ld\n",
- GET_LWP (event_lp->ptid));
+ "SEL: Select single-step %s\n",
+ target_pid_to_str (event_lp->ptid));
}
else
{
/* No single-stepping LWP. Select one at random, out of those
- which have had SIGTRAP events. */
+ which have had SIGTRAP events. */
/* First see how many SIGTRAP events we have. */
iterate_over_lwps (count_events_callback, &num_events);
((num_events * (double) rand ()) / (RAND_MAX + 1.0));
if (debug_lin_lwp && num_events > 1)
- fprintf_unfiltered (gdb_stdlog,
- "Found %d SIGTRAP events, selecting #%d\n",
+ fprintf_unfiltered (gdb_stdlog,
+ "SEL: Found %d SIGTRAP events, selecting #%d\n",
num_events, random_selector);
event_lp = iterate_over_lwps (select_event_lwp_callback,
{
/* Switch the event LWP. */
*orig_lp = event_lp;
- *status = event_lp->status;
+ *status = event_lp->status;
}
/* Flush the wait status for the event LWP. */
if (pid == -1 && errno == ECHILD)
/* Try again with __WCLONE to check cloned processes. */
pid = waitpid (GET_PID (ptid), &status, __WCLONE);
+
+ if (debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "CW: waitpid %ld received %s\n",
+ (long) pid, status_to_str (status));
+ }
+
save_errno = errno;
+ /* Make sure we don't report an event for the exit of the
+ original program, if we've detached from it. */
+ if (pid != -1 && !WIFSTOPPED (status) && pid != GET_PID (inferior_ptid))
+ {
+ pid = -1;
+ save_errno = EINTR;
+ }
+
+ /* Check for stop events reported by a process we didn't already
+ know about - in this case, anything other than inferior_ptid.
+
+ If we're expecting to receive stopped processes after fork,
+ vfork, and clone events, then we'll just add the new one to
+ our list and go back to waiting for the event to be reported
+ - the stopped process might be returned from waitpid before
+ or after the event is. If we want to handle debugging of
+ CLONE_PTRACE processes we need to do more here, i.e. switch
+ to multi-threaded mode. */
+ if (pid != -1 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP
+ && pid != GET_PID (inferior_ptid))
+ {
+ linux_record_stopped_pid (pid);
+ pid = -1;
+ save_errno = EINTR;
+ }
+
clear_sigio_trap ();
clear_sigint_trap ();
}
if (pid == -1)
{
- warning ("Child process unexpectedly missing: %s", safe_strerror (errno));
+ warning ("Child process unexpectedly missing: %s",
+ safe_strerror (errno));
/* Claim it exited with unknown signal. */
ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
return minus_one_ptid;
}
+ /* Handle GNU/Linux's extended waitstatus for trace events. */
+ if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
+ return linux_handle_extended_wait (pid, status, ourstatus);
+
store_waitstatus (ourstatus, status);
return pid_to_ptid (pid);
}
#endif
+/* Stop an active thread, verify it still exists, then resume it. */
+
+static int
+stop_and_resume_callback (struct lwp_info *lp, void *data)
+{
+ struct lwp_info *ptr;
+
+ if (!lp->stopped && !lp->signalled)
+ {
+ stop_callback (lp, NULL);
+ stop_wait_callback (lp, NULL);
+ /* Resume if the lwp still exists. */
+ for (ptr = lwp_list; ptr; ptr = ptr->next)
+ if (lp == ptr)
+ {
+ resume_callback (lp, NULL);
+ resume_set_callback (lp, NULL);
+ }
+ }
+ return 0;
+}
+
static ptid_t
lin_lwp_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
{
sigemptyset (&flush_mask);
/* Make sure SIGCHLD is blocked. */
- if (! sigismember (&blocked_mask, SIGCHLD))
+ if (!sigismember (&blocked_mask, SIGCHLD))
{
sigaddset (&blocked_mask, SIGCHLD);
sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
}
- retry:
+retry:
/* Make sure there is at least one LWP that has been resumed, at
least if there are any LWPs at all. */
if (debug_lin_lwp && status)
fprintf_unfiltered (gdb_stdlog,
- "Using pending wait status %s for LWP %ld.\n",
- status_to_str (status), GET_LWP (lp->ptid));
+ "LLW: Using pending wait status %s for %s.\n",
+ status_to_str (status),
+ target_pid_to_str (lp->ptid));
}
/* But if we don't fine one, we'll have to wait, and check both
else if (is_lwp (ptid))
{
if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "Waiting for specific LWP %ld.\n",
- GET_LWP (ptid));
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: Waiting for specific LWP %s.\n",
+ target_pid_to_str (ptid));
/* We have a specific LWP to check. */
lp = find_lwp_pid (ptid);
if (debug_lin_lwp && status)
fprintf_unfiltered (gdb_stdlog,
- "Using pending wait status %s for LWP %ld.\n",
- status_to_str (status), GET_LWP (lp->ptid));
+ "LLW: Using pending wait status %s for %s.\n",
+ status_to_str (status),
+ target_pid_to_str (lp->ptid));
/* If we have to wait, take into account whether PID is a cloned
process or not. And we have to convert it to something that
if (status && lp->signalled)
{
/* A pending SIGSTOP may interfere with the normal stream of
- events. In a typical case where interference is a problem,
- we have a SIGSTOP signal pending for LWP A while
- single-stepping it, encounter an event in LWP B, and take the
- pending SIGSTOP while trying to stop LWP A. After processing
- the event in LWP B, LWP A is continued, and we'll never see
- the SIGTRAP associated with the last time we were
- single-stepping LWP A. */
+ events. In a typical case where interference is a problem,
+ we have a SIGSTOP signal pending for LWP A while
+ single-stepping it, encounter an event in LWP B, and take the
+ pending SIGSTOP while trying to stop LWP A. After processing
+ the event in LWP B, LWP A is continued, and we'll never see
+ the SIGTRAP associated with the last time we were
+ single-stepping LWP A. */
/* Resume the thread. It should halt immediately returning the
- pending SIGSTOP. */
+ pending SIGSTOP. */
+ registers_changed ();
child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step,
- TARGET_SIGNAL_0);
+ TARGET_SIGNAL_0);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: %s %s, 0, 0 (expect SIGSTOP)\n",
+ lp->step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
+ target_pid_to_str (lp->ptid));
lp->stopped = 0;
gdb_assert (lp->resumed);
stop_wait_callback (lp, NULL);
}
- set_sigint_trap (); /* Causes SIGINT to be passed on to the
- attached process. */
+ set_sigint_trap (); /* Causes SIGINT to be passed on to the
+ attached process. */
set_sigio_trap ();
while (status == 0)
{
gdb_assert (pid == -1 || lwpid == pid);
+ if (debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: waitpid %ld received %s\n",
+ (long) lwpid, status_to_str (status));
+ }
+
lp = find_lwp_pid (pid_to_ptid (lwpid));
- if (! lp)
+
+ /* Check for stop events reported by a process we didn't
+ already know about - anything not already in our LWP
+ list.
+
+ If we're expecting to receive stopped processes after
+ fork, vfork, and clone events, then we'll just add the
+ new one to our list and go back to waiting for the event
+ to be reported - the stopped process might be returned
+ from waitpid before or after the event is. */
+ if (WIFSTOPPED (status) && !lp)
+ {
+ linux_record_stopped_pid (lwpid);
+ status = 0;
+ continue;
+ }
+
+ /* Make sure we don't report an event for the exit of an LWP not in
+ our list, i.e. not part of the current process. This can happen
+ if we detach from a program we original forked and then it
+ exits. */
+ if (!WIFSTOPPED (status) && !lp)
+ {
+ status = 0;
+ continue;
+ }
+
+ /* NOTE drow/2003-06-17: This code seems to be meant for debugging
+ CLONE_PTRACE processes which do not use the thread library -
+ otherwise we wouldn't find the new LWP this way. That doesn't
+ currently work, and the following code is currently unreachable
+ due to the two blocks above. If it's fixed some day, this code
+ should be broken out into a function so that we can also pick up
+ LWPs from the new interface. */
+ if (!lp)
{
lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid)));
if (options & __WCLONE)
&& WSTOPSIG (status) == SIGSTOP);
lp->signalled = 1;
- if (! in_thread_list (inferior_ptid))
+ if (!in_thread_list (inferior_ptid))
{
inferior_ptid = BUILD_LWP (GET_PID (inferior_ptid),
- GET_PID (inferior_ptid));
+ GET_PID (inferior_ptid));
add_thread (inferior_ptid);
}
}
}
- /* Make sure we don't report a TARGET_WAITKIND_EXITED or
- TARGET_WAITKIND_SIGNALLED event if there are still LWP's
- left in the process. */
+ /* Check if the thread has exited. */
if ((WIFEXITED (status) || WIFSIGNALED (status)) && num_lwps > 1)
{
if (in_thread_list (lp->ptid))
{
/* Core GDB cannot deal with us deleting the current
- thread. */
- if (! ptid_equal (lp->ptid, inferior_ptid))
+ thread. */
+ if (!ptid_equal (lp->ptid, inferior_ptid))
+ delete_thread (lp->ptid);
+ printf_unfiltered ("[%s exited]\n",
+ target_pid_to_str (lp->ptid));
+ }
+
+ /* If this is the main thread, we must stop all threads and
+ verify if they are still alive. This is because in the nptl
+ thread model, there is no signal issued for exiting LWPs
+ other than the main thread. We only get the main thread
+ exit signal once all child threads have already exited.
+ If we stop all the threads and use the stop_wait_callback
+ to check if they have exited we can determine whether this
+ signal should be ignored or whether it means the end of the
+ debugged application, regardless of which threading model
+ is being used. */
+ if (GET_PID (lp->ptid) == GET_LWP (lp->ptid))
+ {
+ lp->stopped = 1;
+ iterate_over_lwps (stop_and_resume_callback, NULL);
+ }
+
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: %s exited.\n",
+ target_pid_to_str (lp->ptid));
+
+ delete_lwp (lp->ptid);
+
+ /* If there is at least one more LWP, then the exit signal
+ was not the end of the debugged application and should be
+ ignored. */
+ if (num_lwps > 0)
+ {
+ /* Make sure there is at least one thread running. */
+ gdb_assert (iterate_over_lwps (running_callback, NULL));
+
+ /* Discard the event. */
+ status = 0;
+ continue;
+ }
+ }
+
+ /* Check if the current LWP has previously exited. In the nptl
+ thread model, LWPs other than the main thread do not issue
+ signals when they exit so we must check whenever the thread
+ has stopped. A similar check is made in stop_wait_callback(). */
+ if (num_lwps > 1 && !lin_lwp_thread_alive (lp->ptid))
+ {
+ if (in_thread_list (lp->ptid))
+ {
+ /* Core GDB cannot deal with us deleting the current
+ thread. */
+ if (!ptid_equal (lp->ptid, inferior_ptid))
delete_thread (lp->ptid);
printf_unfiltered ("[%s exited]\n",
target_pid_to_str (lp->ptid));
}
if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "%s exited.\n",
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: %s exited.\n",
target_pid_to_str (lp->ptid));
delete_lwp (lp->ptid);
}
/* Make sure we don't report a SIGSTOP that we sent
- ourselves in an attempt to stop an LWP. */
- if (lp->signalled && WIFSTOPPED (status)
- && WSTOPSIG (status) == SIGSTOP)
+ ourselves in an attempt to stop an LWP. */
+ if (lp->signalled
+ && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
{
if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "Delayed SIGSTOP caught for %s.\n",
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: Delayed SIGSTOP caught for %s.\n",
target_pid_to_str (lp->ptid));
/* This is a delayed SIGSTOP. */
lp->signalled = 0;
+ registers_changed ();
child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step,
- TARGET_SIGNAL_0);
+ TARGET_SIGNAL_0);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
+ lp->step ?
+ "PTRACE_SINGLESTEP" : "PTRACE_CONT",
+ target_pid_to_str (lp->ptid));
+
lp->stopped = 0;
gdb_assert (lp->resumed);
&& signal_pass_state (signo) == 1)
{
/* FIMXE: kettenis/2001-06-06: Should we resume all threads
- here? It is not clear we should. GDB may not expect
- other threads to run. On the other hand, not resuming
- newly attached threads may cause an unwanted delay in
- getting them running. */
+ here? It is not clear we should. GDB may not expect
+ other threads to run. On the other hand, not resuming
+ newly attached threads may cause an unwanted delay in
+ getting them running. */
+ registers_changed ();
child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, signo);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: %s %s, %s (preempt 'handle')\n",
+ lp->step ?
+ "PTRACE_SINGLESTEP" : "PTRACE_CONT",
+ target_pid_to_str (lp->ptid),
+ signo ? strsignal (signo) : "0");
lp->stopped = 0;
status = 0;
goto retry;
}
- if (signo == TARGET_SIGNAL_INT
- && signal_pass_state (signo) == 0)
+ if (signo == TARGET_SIGNAL_INT && signal_pass_state (signo) == 0)
{
/* If ^C/BREAK is typed at the tty/console, SIGINT gets
- forwarded to the entire process group, that is, all LWP's
- will receive it. Since we only want to report it once,
- we try to flush it from all LWPs except this one. */
+ forwarded to the entire process group, that is, all LWP's
+ will receive it. Since we only want to report it once,
+ we try to flush it from all LWPs except this one. */
sigaddset (&flush_mask, SIGINT);
}
}
lp->stopped = 1;
if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog, "Candidate event %s in LWP %ld.\n",
- status_to_str (status), GET_LWP (lp->ptid));
+ fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
+ status_to_str (status), target_pid_to_str (lp->ptid));
/* Now stop all other LWP's ... */
iterate_over_lwps (stop_callback, NULL);
/* ... and wait until all of them have reported back that they're no
longer running. */
iterate_over_lwps (stop_wait_callback, &flush_mask);
+ iterate_over_lwps (flush_callback, &flush_mask);
/* If we're not waiting for a specific LWP, choose an event LWP from
among those that have had events. Giving equal priority to all
{
trap_ptid = (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid)));
if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: trap_ptid is %ld\n",
- GET_LWP (trap_ptid));
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: trap_ptid is %s.\n",
+ target_pid_to_str (trap_ptid));
}
else
trap_ptid = null_ptid;
+ /* Handle GNU/Linux's extended waitstatus for trace events. */
+ if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
+ {
+ linux_handle_extended_wait (ptid_get_pid (trap_ptid),
+ status, ourstatus);
+ return trap_ptid;
+ }
+
store_waitstatus (ourstatus, status);
return (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid)));
}
static int
kill_callback (struct lwp_info *lp, void *data)
{
+ errno = 0;
ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
+ target_pid_to_str (lp->ptid),
+ errno ? safe_strerror (errno) : "OK");
+
return 0;
}
do
{
pid = waitpid (GET_LWP (lp->ptid), NULL, __WCLONE);
+ if (pid != (pid_t) -1 && debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "KWC: wait %s received unknown.\n",
+ target_pid_to_str (lp->ptid));
+ }
}
while (pid == GET_LWP (lp->ptid));
do
{
pid = waitpid (GET_LWP (lp->ptid), NULL, 0);
+ if (pid != (pid_t) -1 && debug_lin_lwp)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "KWC: wait %s received unk.\n",
+ target_pid_to_str (lp->ptid));
+ }
}
while (pid == GET_LWP (lp->ptid));
child_ops.to_create_inferior (exec_file, allargs, env);
}
-static void
+static void
lin_lwp_mourn_inferior (void)
{
trap_ptid = null_ptid;
child_ops.to_mourn_inferior ();
}
-static void
-lin_lwp_fetch_registers (int regno)
-{
- struct cleanup *old_chain = save_inferior_ptid ();
-
- if (is_lwp (inferior_ptid))
- inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid));
-
- fetch_inferior_registers (regno);
-
- do_cleanups (old_chain);
-}
-
-static void
-lin_lwp_store_registers (int regno)
-{
- struct cleanup *old_chain = save_inferior_ptid ();
-
- if (is_lwp (inferior_ptid))
- inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid));
-
- store_inferior_registers (regno);
-
- do_cleanups (old_chain);
-}
-
static int
lin_lwp_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
- struct mem_attrib *attrib,
- struct target_ops *target)
+ struct mem_attrib *attrib, struct target_ops *target)
{
struct cleanup *old_chain = save_inferior_ptid ();
int xfer;
if (is_lwp (inferior_ptid))
inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid));
- xfer = child_xfer_memory (memaddr, myaddr, len, write, attrib, target);
+ xfer = linux_proc_xfer_memory (memaddr, myaddr, len, write, attrib, target);
+ if (xfer == 0)
+ xfer = child_xfer_memory (memaddr, myaddr, len, write, attrib, target);
do_cleanups (old_chain);
return xfer;
errno = 0;
ptrace (PTRACE_PEEKUSER, GET_LWP (ptid), 0, 0);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLTA: PTRACE_PEEKUSER %s, 0, 0 (%s)\n",
+ target_pid_to_str (ptid),
+ errno ? safe_strerror (errno) : "OK");
if (errno)
return 0;
lin_lwp_ops.to_detach = lin_lwp_detach;
lin_lwp_ops.to_resume = lin_lwp_resume;
lin_lwp_ops.to_wait = lin_lwp_wait;
- lin_lwp_ops.to_fetch_registers = lin_lwp_fetch_registers;
- lin_lwp_ops.to_store_registers = lin_lwp_store_registers;
+ /* fetch_inferior_registers and store_inferior_registers will
+ honor the LWP id, so we can use them directly. */
+ lin_lwp_ops.to_fetch_registers = fetch_inferior_registers;
+ lin_lwp_ops.to_store_registers = store_inferior_registers;
lin_lwp_ops.to_xfer_memory = lin_lwp_xfer_memory;
lin_lwp_ops.to_kill = lin_lwp_kill;
lin_lwp_ops.to_create_inferior = lin_lwp_create_inferior;
lin_lwp_ops.to_mourn_inferior = lin_lwp_mourn_inferior;
lin_lwp_ops.to_thread_alive = lin_lwp_thread_alive;
lin_lwp_ops.to_pid_to_str = lin_lwp_pid_to_str;
+ lin_lwp_ops.to_post_startup_inferior = child_post_startup_inferior;
+ lin_lwp_ops.to_post_attach = child_post_attach;
+ lin_lwp_ops.to_insert_fork_catchpoint = child_insert_fork_catchpoint;
+ lin_lwp_ops.to_insert_vfork_catchpoint = child_insert_vfork_catchpoint;
+ lin_lwp_ops.to_insert_exec_catchpoint = child_insert_exec_catchpoint;
+
lin_lwp_ops.to_stratum = thread_stratum;
lin_lwp_ops.to_has_thread_control = tc_schedlock;
lin_lwp_ops.to_magic = OPS_MAGIC;
sigemptyset (&blocked_mask);
add_show_from_set (add_set_cmd ("lin-lwp", no_class, var_zinteger,
- (char *) &debug_lin_lwp,
+ (char *) &debug_lin_lwp,
"Set debugging of GNU/Linux lwp module.\n\
-Enables printf debugging output.\n",
- &setdebuglist),
- &showdebuglist);
+Enables printf debugging output.\n", &setdebuglist), &showdebuglist);
}
\f
projects / deliverable / binutils-gdb.git / blobdiff