/* Number of queued events in the pipe. */
static volatile int linux_nat_num_queued_events;
-/* If async mode is on, true if we're listening for events; false if
- target events are blocked. */
-static int linux_nat_async_events_enabled;
+/* The possible SIGCHLD handling states. */
-static int linux_nat_async_events (int enable);
+enum sigchld_state
+{
+ /* SIGCHLD disabled, with action set to sigchld_handler, for the
+ sigsuspend in linux_nat_wait. */
+ sigchld_sync,
+ /* SIGCHLD enabled, with action set to async_sigchld_handler. */
+ sigchld_async,
+ /* Set SIGCHLD to default action. Used while creating an
+ inferior. */
+ sigchld_default
+};
+
+/* The current SIGCHLD handling state. */
+static enum sigchld_state linux_nat_async_events_state;
+
+static enum sigchld_state linux_nat_async_events (enum sigchld_state enable);
static void pipe_to_local_event_queue (void);
static void local_event_queue_to_pipe (void);
static void linux_nat_event_pipe_push (int pid, int status, int options);
if (debug_linux_nat_async)
fprintf_unfiltered (gdb_stdlog,
"\
-QWPID: linux_nat_async_events_enabled(%d), linux_nat_num_queued_events(%d)\n",
- linux_nat_async_events_enabled,
+QWPID: linux_nat_async_events_state(%d), linux_nat_num_queued_events(%d)\n",
+ linux_nat_async_events_state,
linux_nat_num_queued_events);
if (flags & __WALL)
int ret;
/* There should be no concurrent calls to waitpid. */
- gdb_assert (!linux_nat_async_events_enabled);
+ gdb_assert (linux_nat_async_events_state == sigchld_sync);
ret = queued_waitpid (pid, status, flags);
if (ret != -1)
/* SIGCHLD action for asynchronous mode. */
static struct sigaction async_sigchld_action;
+
+/* SIGCHLD default action, to pass to new inferiors. */
+static struct sigaction sigchld_default_action;
\f
/* Prototypes for local functions. */
lin_lwp_attach_lwp (ptid_t ptid)
{
struct lwp_info *lp;
- int async_events_were_enabled = 0;
+ enum sigchld_state async_events_original_state;
gdb_assert (is_lwp (ptid));
- if (target_can_async_p ())
- async_events_were_enabled = linux_nat_async_events (0);
+ async_events_original_state = linux_nat_async_events (sigchld_sync);
lp = find_lwp_pid (ptid);
lp->stopped = 1;
}
- if (async_events_were_enabled)
- linux_nat_async_events (1);
-
+ linux_nat_async_events (async_events_original_state);
return 0;
}
we have to mask the async mode. */
if (target_can_async_p ())
+ /* Mask async mode. Creating a child requires a loop calling
+ wait_for_inferior currently. */
saved_async = linux_nat_async_mask (0);
else
{
sigdelset (&suspend_mask, SIGCHLD);
}
+ /* Set SIGCHLD to the default action, until after execing the child,
+ since the inferior inherits the superior's signal mask. It will
+ be blocked again in linux_nat_wait, which is only reached after
+ the inferior execing. */
+ linux_nat_async_events (sigchld_default);
+
linux_ops->to_create_inferior (exec_file, allargs, env, from_tty);
if (saved_async)
if (target_can_async_p ())
/* Block events while we're here. */
- linux_nat_async_events (0);
+ linux_nat_async_events (sigchld_sync);
/* A specific PTID means `step only this process id'. */
resume_all = (PIDGET (ptid) == -1);
sigemptyset (&flush_mask);
- if (target_can_async_p ())
- /* Block events while we're here. */
- target_async (NULL, 0);
+ /* Block events while we're here. */
+ linux_nat_async_events (sigchld_sync);
retry:
sigchld_handler (int signo)
{
if (linux_nat_async_enabled
- && linux_nat_async_events_enabled
+ && linux_nat_async_events_state != sigchld_sync
&& signo == SIGCHLD)
/* It is *always* a bug to hit this. */
internal_error (__FILE__, __LINE__,
{
linux_nat_async (NULL, 0);
linux_nat_async_mask_value = mask;
- /* We're in sync mode. Make sure SIGCHLD isn't handled by
- async_sigchld_handler when we come out of sigsuspend in
- linux_nat_wait. */
- sigaction (SIGCHLD, &sync_sigchld_action, NULL);
}
else
{
- /* Restore the async handler. */
- sigaction (SIGCHLD, &async_sigchld_action, NULL);
linux_nat_async_mask_value = mask;
linux_nat_async (inferior_event_handler, 0);
}
{
int status, options, pid;
- if (!linux_nat_async_enabled || !linux_nat_async_events_enabled)
+ if (!linux_nat_async_enabled
+ || linux_nat_async_events_state != sigchld_async)
internal_error (__FILE__, __LINE__,
"get_pending_events called with async masked");
get_pending_events ();
}
-/* Enable or disable async SIGCHLD handling. */
+/* Set SIGCHLD handling state to STATE. Returns previous state. */
-static int
-linux_nat_async_events (int enable)
+static enum sigchld_state
+linux_nat_async_events (enum sigchld_state state)
{
- int current_state = linux_nat_async_events_enabled;
+ enum sigchld_state current_state = linux_nat_async_events_state;
if (debug_linux_nat_async)
fprintf_unfiltered (gdb_stdlog,
- "LNAE: enable(%d): linux_nat_async_events_enabled(%d), "
+ "LNAE: state(%d): linux_nat_async_events_state(%d), "
"linux_nat_num_queued_events(%d)\n",
- enable, linux_nat_async_events_enabled,
+ state, linux_nat_async_events_state,
linux_nat_num_queued_events);
- if (current_state != enable)
+ if (current_state != state)
{
sigset_t mask;
sigemptyset (&mask);
sigaddset (&mask, SIGCHLD);
- if (enable)
- {
- /* Unblock target events. */
- linux_nat_async_events_enabled = 1;
-
- local_event_queue_to_pipe ();
- /* While in masked async, we may have not collected all the
- pending events. Get them out now. */
- get_pending_events ();
- sigprocmask (SIG_UNBLOCK, &mask, NULL);
- }
- else
+
+ /* Always block before changing state. */
+ sigprocmask (SIG_BLOCK, &mask, NULL);
+
+ /* Set new state. */
+ linux_nat_async_events_state = state;
+
+ switch (state)
{
- /* Block target events. */
- sigprocmask (SIG_BLOCK, &mask, NULL);
- linux_nat_async_events_enabled = 0;
- /* Get events out of queue, and make them available to
- queued_waitpid / my_waitpid. */
- pipe_to_local_event_queue ();
+ case sigchld_sync:
+ {
+ /* Block target events. */
+ sigprocmask (SIG_BLOCK, &mask, NULL);
+ sigaction (SIGCHLD, &sync_sigchld_action, NULL);
+ /* Get events out of queue, and make them available to
+ queued_waitpid / my_waitpid. */
+ pipe_to_local_event_queue ();
+ }
+ break;
+ case sigchld_async:
+ {
+ /* Unblock target events for async mode. */
+
+ sigprocmask (SIG_BLOCK, &mask, NULL);
+
+ /* Put events we already waited on, in the pipe first, so
+ events are FIFO. */
+ local_event_queue_to_pipe ();
+ /* While in masked async, we may have not collected all
+ the pending events. Get them out now. */
+ get_pending_events ();
+
+ /* Let'em come. */
+ sigaction (SIGCHLD, &async_sigchld_action, NULL);
+ sigprocmask (SIG_UNBLOCK, &mask, NULL);
+ }
+ break;
+ case sigchld_default:
+ {
+ /* SIGCHLD default mode. */
+ sigaction (SIGCHLD, &sigchld_default_action, NULL);
+
+ /* Get events out of queue, and make them available to
+ queued_waitpid / my_waitpid. */
+ pipe_to_local_event_queue ();
+
+ /* Unblock SIGCHLD. */
+ sigprocmask (SIG_UNBLOCK, &mask, NULL);
+ }
+ break;
}
}
add_file_handler (linux_nat_event_pipe[0],
linux_nat_async_file_handler, NULL);
- linux_nat_async_events (1);
+ linux_nat_async_events (sigchld_async);
}
else
{
async_client_callback = callback;
async_client_context = context;
- linux_nat_async_events (0);
+ linux_nat_async_events (sigchld_sync);
delete_file_handler (linux_nat_event_pipe[0]);
}
return;
if (on)
{
gdb_assert (waitpid_queue == NULL);
- sigaction (SIGCHLD, &async_sigchld_action, NULL);
-
if (pipe (linux_nat_event_pipe) == -1)
internal_error (__FILE__, __LINE__,
"creating event pipe failed.");
-
fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
}
else
{
- sigaction (SIGCHLD, &sync_sigchld_action, NULL);
-
drain_queued_events (-1);
-
linux_nat_num_queued_events = 0;
close (linux_nat_event_pipe[0]);
close (linux_nat_event_pipe[1]);
&maintenance_set_cmdlist,
&maintenance_show_cmdlist);
+ /* Get the default SIGCHLD action. Used while forking an inferior
+ (see linux_nat_create_inferior/linux_nat_async_events). */
+ sigaction (SIGCHLD, NULL, &sigchld_default_action);
+
/* Block SIGCHLD by default. Doing this early prevents it getting
unblocked if an exception is thrown due to an error while the
inferior is starting (sigsetjmp/siglongjmp). */
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