/* Multi-threaded debugging support for Linux (LWP layer).
- Copyright 2000 Free Software Foundation, Inc.
+ Copyright 2000, 2001 Free Software Foundation, Inc.
This file is part of GDB.
#include "gdbthread.h"
#include "inferior.h"
#include "target.h"
+#include "regcache.h"
+#include "gdbcmd.h"
-#define DEBUG 1
-
-#if DEBUG
+static int debug_lin_lwp;
extern const char *strsignal (int sig);
-#endif
/* On Linux there are no real LWP's. The closest thing to LWP's are
processes sharing the same VM space. A multi-threaded process is
cannot use it since GDB must work on older systems too.
- When a traced, cloned process exits and is waited for by the
- debugger, the kernel reassigns it to the origional parent and
+ debugger, the kernel reassigns it to the original parent and
keeps it around as a "zombie". Somehow, the LinuxThreads library
doesn't notice this, which leads to the "zombie problem": When
debugged a multi-threaded process that spawns a lot of threads
{
/* The process id of the LWP. This is a combination of the LWP id
and overall process id. */
- int pid;
+ ptid_t ptid;
/* Non-zero if we sent this LWP a SIGSTOP (but the LWP didn't report
it back yet). */
/* 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;
static int threaded;
\f
-#ifndef TIDGET
-#define TIDGET(PID) (((PID) & 0x7fffffff) >> 16)
-#define PIDGET(PID) (((PID) & 0xffff))
-#define MERGEPID(PID, TID) (((PID) & 0xffff) | ((TID) << 16))
-#endif
-
-#define THREAD_FLAG 0x80000000
-#define is_lwp(pid) (((pid) & THREAD_FLAG) == 0 && TIDGET (pid))
-#define GET_LWP(pid) TIDGET (pid)
-#define GET_PID(pid) PIDGET (pid)
-#define BUILD_LWP(tid, pid) MERGEPID (pid, tid)
+#define GET_LWP(ptid) ptid_get_lwp (ptid)
+#define GET_PID(ptid) ptid_get_pid (ptid)
+#define is_lwp(ptid) (GET_LWP (ptid) != 0)
+#define BUILD_LWP(lwp, pid) ptid_build (pid, lwp, 0)
#define is_cloned(pid) (GET_LWP (pid) != GET_PID (pid))
/* If the last reported event was a SIGTRAP, this variable is set to
the process id of the LWP/thread that got it. */
-int trap_pid;
+ptid_t trap_ptid;
\f
/* This module's target-specific operations. */
/* Since we cannot wait (in lin_lwp_wait) for the initial process and
any cloned processes with a single call to waitpid, we have to use
- use the WNOHANG flag and call waitpid in a loop. To optimize
+ the WNOHANG flag and call waitpid in a loop. To optimize
things a bit we use `sigsuspend' to wake us up when a process has
something to report (it will send us a SIGCHLD if it has). To make
this work we have to juggle with the signal mask. We save the
- origional signal mask such that we can restore it before creating a
+ original signal mask such that we can restore it before creating a
new process in order to avoid blocking certain signals in the
inferior. We then block SIGCHLD during the waitpid/sigsuspend
loop. */
-/* Origional signal mask. */
+/* Original signal mask. */
static sigset_t normal_mask;
/* Signal mask for use with sigsuspend in lin_lwp_wait, initialized in
\f
/* Prototypes for local functions. */
-static void lin_lwp_mourn_inferior (void);
+static int stop_wait_callback (struct lwp_info *lp, void *data);
\f
+/* Convert wait status STATUS to a string. Used for printing debug
+ messages only. */
-/* Initialize the list of LWPs. */
+static char *
+status_to_str (int status)
+{
+ static char buf[64];
+
+ if (WIFSTOPPED (status))
+ snprintf (buf, sizeof (buf), "%s (stopped)",
+ strsignal (WSTOPSIG (status)));
+ else if (WIFSIGNALED (status))
+ snprintf (buf, sizeof (buf), "%s (terminated)",
+ strsignal (WSTOPSIG (status)));
+ else
+ snprintf (buf, sizeof (buf), "%d (exited)",
+ WEXITSTATUS (status));
+
+ return buf;
+}
+\f
+/* Initialize the list of LWPs. Note that this module, contrary to
+ what GDB's generic threads layer does for its thread list,
+ re-initializes the LWP lists whenever we mourn or detach (which
+ doesn't involve mourning) the inferior. */
static void
init_lwp_list (void)
for (lp = lwp_list; lp; lp = lpnext)
{
lpnext = lp->next;
- free (lp);
+ xfree (lp);
}
lwp_list = NULL;
Return a pointer to the structure describing the new LWP. */
static struct lwp_info *
-add_lwp (int pid)
+add_lwp (ptid_t ptid)
{
struct lwp_info *lp;
- gdb_assert (is_lwp (pid));
+ gdb_assert (is_lwp (ptid));
lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
memset (lp, 0, sizeof (struct lwp_info));
- lp->pid = pid;
+ lp->ptid = ptid;
lp->next = lwp_list;
lwp_list = lp;
/* Remove the LWP specified by PID from the list. */
static void
-delete_lwp (int pid)
+delete_lwp (ptid_t ptid)
{
struct lwp_info *lp, *lpprev;
lpprev = NULL;
for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
- if (lp->pid == pid)
+ if (ptid_equal (lp->ptid, ptid))
break;
if (!lp)
else
lwp_list = lp->next;
- free (lp);
+ xfree (lp);
}
/* Return a pointer to the structure describing the LWP corresponding
to PID. If no corresponding LWP could be found, return NULL. */
static struct lwp_info *
-find_lwp_pid (int pid)
+find_lwp_pid (ptid_t ptid)
{
struct lwp_info *lp;
+ int lwp;
- if (is_lwp (pid))
- pid = GET_LWP (pid);
+ if (is_lwp (ptid))
+ lwp = GET_LWP (ptid);
+ else
+ lwp = GET_PID (ptid);
for (lp = lwp_list; lp; lp = lp->next)
- if (pid == GET_LWP (lp->pid))
+ if (lwp == GET_LWP (lp->ptid))
return lp;
return NULL;
struct lwp_info *
iterate_over_lwps (int (*callback) (struct lwp_info *, void *), void *data)
{
- struct lwp_info *lp;
+ struct lwp_info *lp, *lpnext;
- for (lp = lwp_list; lp; lp = lp->next)
- if ((*callback) (lp, data))
- return lp;
+ for (lp = lwp_list; lp; lp = lpnext)
+ {
+ lpnext = lp->next;
+ if ((*callback) (lp, data))
+ return lp;
+ }
return NULL;
}
\f
-/* Helper functions. */
+/* Implementation of the PREPARE_TO_PROCEED hook for the Linux LWP
+ layer.
-static void
-restore_inferior_pid (void *arg)
-{
- int *saved_pid_ptr = arg;
- inferior_pid = *saved_pid_ptr;
- free (arg);
-}
+ Note that this implementation is potentially redundant now that
+ default_prepare_to_proceed() has been added.
-static struct cleanup *
-save_inferior_pid (void)
-{
- int *saved_pid_ptr;
-
- saved_pid_ptr = xmalloc (sizeof (int));
- *saved_pid_ptr = inferior_pid;
- return make_cleanup (restore_inferior_pid, saved_pid_ptr);
-}
-\f
-
-/* Implementation of the PREPARE_TO_PROCEED hook for the Linux LWP layer. */
+ 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 (trap_pid && inferior_pid != trap_pid)
+ if (! ptid_equal (trap_ptid, null_ptid)
+ && ! ptid_equal (inferior_ptid, trap_ptid))
{
/* Switched over from TRAP_PID. */
CORE_ADDR stop_pc = read_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_pid);
+ 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_pid = trap_pid;
+ inferior_ptid = trap_ptid;
/* FIXME: Is this stuff really necessary? */
flush_cached_frames ();
process. */
void
-lin_lwp_attach_lwp (int pid, int verbose)
+lin_lwp_attach_lwp (ptid_t ptid, int verbose)
{
struct lwp_info *lp;
- gdb_assert (is_lwp (pid));
+ gdb_assert (is_lwp (ptid));
if (verbose)
- printf_filtered ("[New %s]\n", target_pid_to_str (pid));
+ printf_filtered ("[New %s]\n", target_pid_to_str (ptid));
- if (ptrace (PTRACE_ATTACH, GET_LWP (pid), 0, 0) < 0)
- error ("Can't attach %s: %s", target_pid_to_str (pid), strerror (errno));
+ /* We assume that we're already tracing the initial process. */
+ if (is_cloned (ptid) && ptrace (PTRACE_ATTACH, GET_LWP (ptid), 0, 0) < 0)
+ error ("Can't attach %s: %s", target_pid_to_str (ptid), strerror (errno));
- lp = add_lwp (pid);
- lp->signalled = 1;
+ lp = find_lwp_pid (ptid);
+ if (lp == NULL)
+ lp = add_lwp (ptid);
+
+ if (is_cloned (ptid))
+ {
+ lp->signalled = 1;
+ stop_wait_callback (lp, NULL);
+ }
}
static void
lin_lwp_attach (char *args, int from_tty)
{
+ struct lwp_info *lp;
+
/* FIXME: We should probably accept a list of process id's, and
attach all of them. */
- error("Not implemented yet");
+ child_ops.to_attach (args, from_tty);
+
+ /* Add the initial process as the first LWP to the list. */
+ lp = add_lwp (BUILD_LWP (PIDGET (inferior_ptid), PIDGET (inferior_ptid)));
+
+ /* Make sure the initial process is stopped. The user-level threads
+ layer might want to poke around in the inferior, and that won't
+ work if things haven't stabilized yet. */
+ lp->signalled = 1;
+ stop_wait_callback (lp, NULL);
+ gdb_assert (lp->status == 0);
+
+ /* Fake the SIGSTOP that core GDB expects. */
+ lp->status = W_STOPCODE (SIGSTOP);
+ lp->resumed = 1;
+}
+
+static int
+detach_callback (struct lwp_info *lp, void *data)
+{
+ 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));
+
+ while (lp->signalled && lp->stopped)
+ {
+ 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),
+ strerror (errno));
+
+ lp->stopped = 0;
+ lp->signalled = 0;
+ lp->status = 0;
+ stop_wait_callback (lp, NULL);
+
+ gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
+ }
+
+ if (is_cloned (lp->ptid))
+ {
+ 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),
+ strerror (errno));
+
+ delete_lwp (lp->ptid);
+ }
+
+ return 0;
}
static void
lin_lwp_detach (char *args, int from_tty)
{
- /* FIXME: Provide implementation when we implement lin_lwp_attach. */
- error ("Not implemented yet");
+ iterate_over_lwps (detach_callback, NULL);
+
+ /* Only the initial (uncloned) process should be left right now. */
+ gdb_assert (num_lwps == 1);
+
+ trap_ptid = null_ptid;
+
+ /* Destroy LWP info; it's no longer valid. */
+ init_lwp_list ();
+
+ /* Restore the original signal mask. */
+ sigprocmask (SIG_SETMASK, &normal_mask, NULL);
+ sigemptyset (&blocked_mask);
+
+ inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid));
+ child_ops.to_detach (args, from_tty);
}
\f
{
struct lwp_info *lp = data;
- if (tp->private->lwpid == GET_LWP (lp->pid))
+ if (tp->private->lwpid == GET_LWP (lp->ptid))
return 1;
return 0;
{
struct thread_info *tp;
-#if 1
+#if 0
/* FIXME: kettenis/2000-08-26: This should really be handled
properly by core GDB. */
- tp = find_thread_pid (lp->pid);
+ tp = find_thread_pid (lp->ptid);
if (tp == NULL)
tp = iterate_over_threads (find_lwp_callback, lp);
gdb_assert (tp);
}
#endif
- child_resume (GET_LWP (lp->pid), 0, TARGET_SIGNAL_0);
+ child_resume (pid_to_ptid (GET_LWP (lp->ptid)), 0, TARGET_SIGNAL_0);
lp->stopped = 0;
lp->step = 0;
}
return 0;
}
+static int
+resume_clear_callback (struct lwp_info *lp, void *data)
+{
+ lp->resumed = 0;
+ return 0;
+}
+
+static int
+resume_set_callback (struct lwp_info *lp, void *data)
+{
+ lp->resumed = 1;
+ return 0;
+}
+
static void
-lin_lwp_resume (int pid, int step, enum target_signal signo)
+lin_lwp_resume (ptid_t ptid, int step, enum target_signal signo)
{
struct lwp_info *lp;
int resume_all;
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 = (pid == -1) || !step;
+ resume_all = (PIDGET (ptid) == -1) || !step;
+
+ if (resume_all)
+ iterate_over_lwps (resume_set_callback, NULL);
+ else
+ iterate_over_lwps (resume_clear_callback, NULL);
/* If PID is -1, it's the current inferior that should be
- handled special. */
- if (pid == -1)
- pid = inferior_pid;
+ handled specially. */
+ if (PIDGET (ptid) == -1)
+ ptid = inferior_ptid;
- lp = find_lwp_pid (pid);
+ lp = find_lwp_pid (ptid);
if (lp)
{
- pid = GET_LWP (lp->pid);
-
- /* Mark LWP as not stopped to prevent it from being continued by
- resume_callback. */
- lp->stopped = 0;
+ ptid = pid_to_ptid (GET_LWP (lp->ptid));
/* Remember if we're stepping. */
lp->step = step;
+ /* Mark this LWP as resumed. */
+ lp->resumed = 1;
+
/* If we have a pending wait status for this thread, there is no
point in resuming the process. */
if (lp->status)
gdb_assert (signo == TARGET_SIGNAL_0);
return;
}
+
+ /* Mark LWP as not stopped to prevent it from being continued by
+ resume_callback. */
+ lp->stopped = 0;
}
if (resume_all)
iterate_over_lwps (resume_callback, NULL);
- child_resume (pid, step, signo);
+ child_resume (ptid, step, signo);
}
\f
{
int ret;
- ret = kill (GET_LWP (lp->pid), SIGSTOP);
+ ret = kill (GET_LWP (lp->ptid), SIGSTOP);
gdb_assert (ret == 0);
lp->signalled = 1;
return 0;
}
-/* Wait until LP is stopped. */
+/* Wait until LP is stopped. If DATA is non-null it is interpreted as
+ a pointer to a set of signals to be flushed immediately. */
static int
stop_wait_callback (struct lwp_info *lp, void *data)
{
+ sigset_t *flush_mask = data;
+
if (! lp->stopped && lp->signalled)
{
pid_t pid;
gdb_assert (lp->status == 0);
- pid = waitpid (GET_LWP (lp->pid), &status,
- is_cloned (lp->pid) ? __WCLONE : 0);
+ pid = waitpid (GET_LWP (lp->ptid), &status,
+ is_cloned (lp->ptid) ? __WCLONE : 0);
if (pid == -1 && errno == ECHILD)
/* OK, the proccess has disappeared. We'll catch the actual
exit event in lin_lwp_wait. */
return 0;
- gdb_assert (pid == GET_LWP (lp->pid));
+ gdb_assert (pid == GET_LWP (lp->ptid));
if (WIFEXITED (status) || WIFSIGNALED (status))
{
gdb_assert (num_lwps > 1);
- if (in_thread_list (lp->pid))
+ if (in_thread_list (lp->ptid))
{
/* Core GDB cannot deal with us deleting the current
thread. */
- if (lp->pid != inferior_pid)
- delete_thread (lp->pid);
+ if (!ptid_equal (lp->ptid, inferior_ptid))
+ delete_thread (lp->ptid);
printf_unfiltered ("[%s exited]\n",
- target_pid_to_str (lp->pid));
+ target_pid_to_str (lp->ptid));
}
-#if DEBUG
- printf ("%s exited.\n", target_pid_to_str (lp->pid));
-#endif
- delete_lwp (lp->pid);
+ 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));
- lp->stopped = 1;
+
+ /* Ignore any signals in FLUSH_MASK. */
+ if (flush_mask && sigismember (flush_mask, WSTOPSIG (status)))
+ {
+ ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
+ return stop_wait_callback (lp, flush_mask);
+ }
if (WSTOPSIG (status) != SIGSTOP)
{
- if (WSTOPSIG (status) == SIGTRAP
- && breakpoint_inserted_here_p (read_pc_pid (pid)
- - DECR_PC_AFTER_BREAK))
+ 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
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. */
-#if DEBUG
- printf ("Tripped breakpoint at %lx in LWP %d"
- " while waiting for SIGSTOP.\n",
- (long) read_pc_pid (lp->pid), pid);
-#endif
- /* Set the PC to before the trap. */
- if (DECR_PC_AFTER_BREAK)
- write_pc_pid (read_pc_pid (pid) - DECR_PC_AFTER_BREAK, pid);
+
+ /* Now resume this LWP and get the SIGSTOP event. */
+ 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));
+ }
+ /* 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));
+ /* Save the sigtrap event. */
+ lp->status = status;
+ return 0;
}
else
{
-#if DEBUG
- printf ("Received %s in LWP %d while waiting for SIGSTOP.\n",
- strsignal (WSTOPSIG (status)), pid);
-#endif
/* The thread was stopped with a signal other than
- SIGSTOP, and didn't accidentiliy trip a breakpoint.
- Record the wait status. */
- lp->status = status;
+ 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));
+ }
+ /* Now resume this LWP and get the SIGSTOP event. */
+ ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
+
+ /* Hold this event/waitstatus while we check to see if
+ 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. */
+ if (lp->status == 0)
+ lp->status = status;
+ else
+ kill (GET_LWP (lp->ptid), WSTOPSIG (status));
+ return 0;
}
}
else
{
/* We caught the SIGSTOP that we intended to catch, so
there's no SIGSTOP pending. */
+ lp->stopped = 1;
lp->signalled = 0;
}
}
static int
status_callback (struct lwp_info *lp, void *data)
{
- return (lp->status != 0);
+ /* Only report a pending wait status if we pretend that this has
+ indeed been resumed. */
+ return (lp->status != 0 && lp->resumed);
}
/* Return non-zero if LP isn't stopped. */
return (lp->stopped == 0);
}
+/* Count the LWP's that have had events. */
+
+static int
+count_events_callback (struct lwp_info *lp, void *data)
+{
+ int *count = data;
+
+ gdb_assert (count != NULL);
+
+ /* Count only LWPs that have a SIGTRAP event pending. */
+ if (lp->status != 0
+ && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP)
+ (*count)++;
+
+ return 0;
+}
+
+/* Select the LWP (if any) that is currently being single-stepped. */
+
+static int
+select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
+{
+ if (lp->step && lp->status != 0)
+ return 1;
+ else
+ return 0;
+}
+
+/* Select the Nth LWP that has had a SIGTRAP event. */
+
+static int
+select_event_lwp_callback (struct lwp_info *lp, void *data)
+{
+ int *selector = data;
+
+ gdb_assert (selector != NULL);
+
+ /* Select only LWPs that have a SIGTRAP event pending. */
+ if (lp->status != 0
+ && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP)
+ if ((*selector)-- == 0)
+ return 1;
+
+ return 0;
+}
+
+static int
+cancel_breakpoints_callback (struct lwp_info *lp, void *data)
+{
+ struct lwp_info *event_lp = data;
+
+ /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
+ if (lp == event_lp)
+ return 0;
+
+ /* 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 LWP will have already
+ tripped on it. */
+
+ if (lp->status != 0
+ && 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));
+
+ /* Back up the PC if necessary. */
+ if (DECR_PC_AFTER_BREAK)
+ write_pc_pid (read_pc_pid (lp->ptid) - DECR_PC_AFTER_BREAK, lp->ptid);
+
+ /* Throw away the SIGTRAP. */
+ lp->status = 0;
+ }
+
+ return 0;
+}
+
+/* Select one LWP out of those that have events pending. */
+
+static void
+select_event_lwp (struct lwp_info **orig_lp, int *status)
+{
+ int num_events = 0;
+ int random_selector;
+ struct lwp_info *event_lp;
+
+ /* Record the wait status for the origional LWP. */
+ (*orig_lp)->status = *status;
+
+ /* Give preference to any LWP that is being single-stepped. */
+ event_lp = iterate_over_lwps (select_singlestep_lwp_callback, NULL);
+ if (event_lp != NULL)
+ {
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "Select single-step LWP %ld\n",
+ GET_LWP (event_lp->ptid));
+ }
+ else
+ {
+ /* No single-stepping LWP. Select one at random, out of those
+ which have had SIGTRAP events. */
+
+ /* First see how many SIGTRAP events we have. */
+ iterate_over_lwps (count_events_callback, &num_events);
+
+ /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
+ random_selector = (int)
+ ((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",
+ num_events, random_selector);
+
+ event_lp = iterate_over_lwps (select_event_lwp_callback,
+ &random_selector);
+ }
+
+ if (event_lp != NULL)
+ {
+ /* Switch the event LWP. */
+ *orig_lp = event_lp;
+ *status = event_lp->status;
+ }
+
+ /* Flush the wait status for the event LWP. */
+ (*orig_lp)->status = 0;
+}
+
+/* Return non-zero if LP has been resumed. */
+
static int
-lin_lwp_wait (int pid, struct target_waitstatus *ourstatus)
+resumed_callback (struct lwp_info *lp, void *data)
+{
+ return lp->resumed;
+}
+
+static ptid_t
+lin_lwp_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
{
struct lwp_info *lp = NULL;
int options = 0;
int status = 0;
+ pid_t pid = PIDGET (ptid);
+ sigset_t flush_mask;
+
+ sigemptyset (&flush_mask);
/* Make sure SIGCHLD is blocked. */
if (! sigismember (&blocked_mask, SIGCHLD))
retry:
+ /* Make sure there is at least one LWP that has been resumed, at
+ least if there are any LWPs at all. */
+ gdb_assert (num_lwps == 0 || iterate_over_lwps (resumed_callback, NULL));
+
/* First check if there is a LWP with a wait status pending. */
if (pid == -1)
{
- /* Any LWP will do. */
+ /* Any LWP that's been resumed will do. */
lp = iterate_over_lwps (status_callback, NULL);
if (lp)
{
-#if DEBUG
- printf ("Using pending wait status for LWP %d.\n",
- GET_LWP (lp->pid));
-#endif
status = lp->status;
lp->status = 0;
+
+ 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));
}
/* But if we don't fine one, we'll have to wait, and check both
processes. */
options = __WCLONE | WNOHANG;
}
- else if (is_lwp (pid))
+ else if (is_lwp (ptid))
{
-#if DEBUG
- printf ("Waiting for specific LWP %d.\n", GET_LWP (pid));
-#endif
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "Waiting for specific LWP %ld.\n",
+ GET_LWP (ptid));
+
/* We have a specific LWP to check. */
- lp = find_lwp_pid (GET_LWP (pid));
+ lp = find_lwp_pid (ptid);
gdb_assert (lp);
status = lp->status;
lp->status = 0;
-#if DEBUG
- if (status)
- printf ("Using pending wait status for LWP %d.\n",
- GET_LWP (lp->pid));
-#endif
+
+ 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));
/* 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
the layer beneath us can understand. */
- options = is_cloned (lp->pid) ? __WCLONE : 0;
- pid = GET_LWP (pid);
+ options = is_cloned (lp->ptid) ? __WCLONE : 0;
+ pid = GET_LWP (ptid);
}
if (status && lp->signalled)
/* Resume the thread. It should halt immediately returning the
pending SIGSTOP. */
- child_resume (GET_LWP (lp->pid), lp->step, TARGET_SIGNAL_0);
+ child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step,
+ TARGET_SIGNAL_0);
lp->stopped = 0;
+ gdb_assert (lp->resumed);
/* This should catch the pending SIGSTOP. */
stop_wait_callback (lp, NULL);
{
gdb_assert (pid == -1 || lwpid == pid);
- lp = find_lwp_pid (lwpid);
+ lp = find_lwp_pid (pid_to_ptid (lwpid));
if (! lp)
{
- lp = add_lwp (BUILD_LWP (lwpid, inferior_pid));
+ lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid)));
if (threaded)
{
gdb_assert (WIFSTOPPED (status)
&& WSTOPSIG (status) == SIGSTOP);
lp->signalled = 1;
- if (! in_thread_list (inferior_pid))
+ if (! in_thread_list (inferior_ptid))
{
- inferior_pid = BUILD_LWP (inferior_pid, inferior_pid);
- add_thread (inferior_pid);
+ inferior_ptid = BUILD_LWP (GET_PID (inferior_ptid),
+ GET_PID (inferior_ptid));
+ add_thread (inferior_ptid);
}
- add_thread (lp->pid);
+ add_thread (lp->ptid);
printf_unfiltered ("[New %s]\n",
- target_pid_to_str (lp->pid));
+ target_pid_to_str (lp->ptid));
}
}
left in the process. */
if ((WIFEXITED (status) || WIFSIGNALED (status)) && num_lwps > 1)
{
- if (in_thread_list (lp->pid))
+ if (in_thread_list (lp->ptid))
{
/* Core GDB cannot deal with us deleting the current
thread. */
- if (lp->pid != inferior_pid)
- delete_thread (lp->pid);
+ if (! ptid_equal (lp->ptid, inferior_ptid))
+ delete_thread (lp->ptid);
printf_unfiltered ("[%s exited]\n",
- target_pid_to_str (lp->pid));
+ target_pid_to_str (lp->ptid));
}
-#if DEBUG
- printf ("%s exited.\n", target_pid_to_str (lp->pid));
-#endif
- delete_lwp (lp->pid);
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "%s exited.\n",
+ target_pid_to_str (lp->ptid));
+
+ delete_lwp (lp->ptid);
/* Make sure there is at least one thread running. */
gdb_assert (iterate_over_lwps (running_callback, NULL));
if (lp->signalled && WIFSTOPPED (status)
&& WSTOPSIG (status) == SIGSTOP)
{
-#if DEBUG
- printf ("Delayed SIGSTOP caught for %s.\n",
- target_pid_to_str (lp->pid));
-#endif
+ if (debug_lin_lwp)
+ fprintf_unfiltered (gdb_stdlog,
+ "Delayed SIGSTOP caught for %s.\n",
+ target_pid_to_str (lp->ptid));
+
/* This is a delayed SIGSTOP. */
lp->signalled = 0;
- child_resume (GET_LWP (lp->pid), lp->step, TARGET_SIGNAL_0);
+ child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step,
+ TARGET_SIGNAL_0);
lp->stopped = 0;
+ gdb_assert (lp->resumed);
/* Discard the event. */
status = 0;
&& signal_print_state (signo) == 0
&& signal_pass_state (signo) == 1)
{
- child_resume (GET_LWP (lp->pid), lp->step, signo);
+ /* 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. */
+ child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, signo);
lp->stopped = 0;
status = 0;
goto retry;
}
+
+ 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. */
+ sigaddset (&flush_mask, SIGINT);
+ }
}
/* This LWP is stopped now. */
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));
+
/* 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, NULL);
+ iterate_over_lwps (stop_wait_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
+ LWPs that have had events helps prevent starvation. */
+ if (pid == -1)
+ select_event_lwp (&lp, &status);
+
+ /* Now that we've selected our final event LWP, cancel any
+ breakpoints in other LWPs that have hit a GDB breakpoint. See
+ the comment in cancel_breakpoints_callback to find out why. */
+ iterate_over_lwps (cancel_breakpoints_callback, lp);
/* If we're not running in "threaded" mode, we'll report the bare
process id. */
if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP)
- trap_pid = (threaded ? lp->pid : GET_LWP (lp->pid));
+ {
+ 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));
+ }
else
- trap_pid = 0;
+ trap_ptid = null_ptid;
store_waitstatus (ourstatus, status);
- return (threaded ? lp->pid : GET_LWP (lp->pid));
+ return (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid)));
}
static int
kill_callback (struct lwp_info *lp, void *data)
{
- ptrace (PTRACE_KILL, GET_LWP (lp->pid), 0, 0);
+ ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0);
return 0;
}
/* For cloned processes we must check both with __WCLONE and
without, since the exit status of a cloned process isn't reported
with __WCLONE. */
- if (is_cloned (lp->pid))
+ if (is_cloned (lp->ptid))
{
do
{
- pid = waitpid (GET_LWP (lp->pid), NULL, __WCLONE);
+ pid = waitpid (GET_LWP (lp->ptid), NULL, __WCLONE);
}
- while (pid == GET_LWP (lp->pid));
+ while (pid == GET_LWP (lp->ptid));
gdb_assert (pid == -1 && errno == ECHILD);
}
do
{
- pid = waitpid (GET_LWP (lp->pid), NULL, 0);
+ pid = waitpid (GET_LWP (lp->ptid), NULL, 0);
}
- while (pid == GET_LWP (lp->pid));
+ while (pid == GET_LWP (lp->ptid));
gdb_assert (pid == -1 && errno == ECHILD);
return 0;
static void
lin_lwp_create_inferior (char *exec_file, char *allargs, char **env)
{
- struct target_ops *target_beneath;
-
- init_lwp_list ();
-
-#if 0
- target_beneath = find_target_beneath (&lin_lwp_ops);
-#else
- target_beneath = &child_ops;
-#endif
- target_beneath->to_create_inferior (exec_file, allargs, env);
+ child_ops.to_create_inferior (exec_file, allargs, env);
}
static void
lin_lwp_mourn_inferior (void)
{
- struct target_ops *target_beneath;
+ trap_ptid = null_ptid;
+ /* Destroy LWP info; it's no longer valid. */
init_lwp_list ();
- trap_pid = 0;
-
- /* Restore the origional signal mask. */
+ /* Restore the original signal mask. */
sigprocmask (SIG_SETMASK, &normal_mask, NULL);
sigemptyset (&blocked_mask);
-#if 0
- target_beneath = find_target_beneath (&lin_lwp_ops);
-#else
- target_beneath = &child_ops;
-#endif
- target_beneath->to_mourn_inferior ();
+ child_ops.to_mourn_inferior ();
}
static void
lin_lwp_fetch_registers (int regno)
{
- struct cleanup *old_chain = save_inferior_pid ();
+ struct cleanup *old_chain = save_inferior_ptid ();
- if (is_lwp (inferior_pid))
- inferior_pid = GET_LWP (inferior_pid);
+ if (is_lwp (inferior_ptid))
+ inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid));
fetch_inferior_registers (regno);
static void
lin_lwp_store_registers (int regno)
{
- struct cleanup *old_chain = save_inferior_pid ();
+ struct cleanup *old_chain = save_inferior_ptid ();
- if (is_lwp (inferior_pid))
- inferior_pid = GET_LWP (inferior_pid);
+ if (is_lwp (inferior_ptid))
+ inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid));
store_inferior_registers (regno);
static int
lin_lwp_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
+ struct mem_attrib *attrib,
struct target_ops *target)
{
- struct cleanup *old_chain = save_inferior_pid ();
+ struct cleanup *old_chain = save_inferior_ptid ();
int xfer;
- if (is_lwp (inferior_pid))
- inferior_pid = GET_LWP (inferior_pid);
+ if (is_lwp (inferior_ptid))
+ inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid));
- xfer = child_xfer_memory (memaddr, myaddr, len, write, target);
+ xfer = child_xfer_memory (memaddr, myaddr, len, write, attrib, target);
do_cleanups (old_chain);
return xfer;
}
static int
-lin_lwp_thread_alive (int pid)
+lin_lwp_thread_alive (ptid_t ptid)
{
- gdb_assert (is_lwp (pid));
+ gdb_assert (is_lwp (ptid));
errno = 0;
- ptrace (PTRACE_PEEKUSER, GET_LWP (pid), 0, 0);
+ ptrace (PTRACE_PEEKUSER, GET_LWP (ptid), 0, 0);
if (errno)
return 0;
}
static char *
-lin_lwp_pid_to_str (int pid)
+lin_lwp_pid_to_str (ptid_t ptid)
{
static char buf[64];
- if (is_lwp (pid))
+ if (is_lwp (ptid))
{
- snprintf (buf, sizeof (buf), "LWP %d", GET_LWP (pid));
+ snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid));
return buf;
}
- return normal_pid_to_str (pid);
+ return normal_pid_to_str (ptid);
}
static void
add_target (&lin_lwp_ops);
thread_db_init (&lin_lwp_ops);
- /* Save the origional signal mask. */
+ /* Save the original signal mask. */
sigprocmask (SIG_SETMASK, NULL, &normal_mask);
action.sa_handler = sigchld_handler;
sigdelset (&suspend_mask, SIGCHLD);
sigemptyset (&blocked_mask);
+
+ add_show_from_set (add_set_cmd ("lin-lwp", no_class, var_zinteger,
+ (char *) &debug_lin_lwp,
+ "Set debugging of linux lwp module.\n\
+Enables printf debugging output.\n",
+ &setdebuglist),
+ &showdebuglist);
}
\f
projects / deliverable / binutils-gdb.git / blobdiff