/* Asynchronous timers.
- Copyright (C) 2000-2012 Free Software Foundation, Inc.
+ Copyright (C) 2000-2014 Free Software Foundation, Inc.
This file is part of GNU Emacs.
along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
-#include <signal.h>
#include <stdio.h>
-#include <setjmp.h>
+
#include "lisp.h"
#include "syssignal.h"
#include "systime.h"
#include "blockinput.h"
#include "atimer.h"
#include <unistd.h>
-#include <sys/time.h>
+
+#ifdef HAVE_TIMERFD
+#include <sys/timerfd.h>
+#ifdef HAVE_TIMERFD_CLOEXEC
+#define TIMERFD_CREATE_FLAGS TFD_CLOEXEC
+#else
+#define TIMERFD_CREATE_FLAGS 0
+#endif /* HAVE_TIMERFD_CLOEXEC */
+#endif /* HAVE_TIMERFD */
/* Free-list of atimer structures. */
static struct atimer *atimers;
-/* Non-zero means alarm_signal_handler has found ripe timers but
- interrupt_input_blocked was non-zero. In this case, timer
- functions are not called until the next UNBLOCK_INPUT because timer
- functions are expected to call X, and X cannot be assumed to be
- reentrant. */
+#if defined (HAVE_TIMERFD)
+/* File descriptor returned by timerfd_create. GNU/Linux-specific. */
+static int timerfd;
+#elif defined (HAVE_ITIMERSPEC)
+/* The alarm timer used if POSIX timers are available. */
+static timer_t alarm_timer;
+#endif
+
+#if defined (HAVE_TIMERFD) || defined (HAVE_ITIMERSPEC)
+/* Non-zero if one of the above was successfully initialized. Do not
+ use bool due to special treatment if HAVE_TIMERFD, see below. */
+static int special_timer_available;
+#endif
-int pending_atimers;
+#ifdef HAVE_CLOCK_GETRES
+/* Resolution of CLOCK_REALTIME clock. */
+static struct timespec resolution;
+#endif
/* Block/unblock SIGALRM. */
-#define BLOCK_ATIMERS sigblock (sigmask (SIGALRM))
-#define UNBLOCK_ATIMERS sigunblock (sigmask (SIGALRM))
+static void
+block_atimers (sigset_t *oldset)
+{
+ sigset_t blocked;
+ sigemptyset (&blocked);
+ sigaddset (&blocked, SIGALRM);
+ sigaddset (&blocked, SIGINT);
+ pthread_sigmask (SIG_BLOCK, &blocked, oldset);
+}
+static void
+unblock_atimers (sigset_t const *oldset)
+{
+ pthread_sigmask (SIG_SETMASK, oldset, 0);
+}
/* Function prototypes. */
static void schedule_atimer (struct atimer *);
static struct atimer *append_atimer_lists (struct atimer *,
struct atimer *);
-static void alarm_signal_handler (int signo);
-
/* Start a new atimer of type TYPE. TIME specifies when the timer is
ripe. FN is the function to call when the timer fires.
to cancel_atimer; don't free it yourself. */
struct atimer *
-start_atimer (enum atimer_type type, EMACS_TIME timestamp, atimer_callback fn,
- void *client_data)
+start_atimer (enum atimer_type type, struct timespec timestamp,
+ atimer_callback fn, void *client_data)
{
struct atimer *t;
-
- /* Round TIME up to the next full second if we don't have
- itimers. */
-#ifndef HAVE_SETITIMER
- if (EMACS_NSECS (timestamp) != 0
- && EMACS_SECS (timestamp) < TYPE_MAXIMUM (time_t))
- {
- EMACS_SET_USECS (timestamp, 0);
- EMACS_SET_SECS (timestamp, EMACS_SECS (timestamp) + 1);
- }
+ sigset_t oldset;
+
+#if !defined (HAVE_SETITIMER)
+ /* Round TIME up to the next full second if we don't have itimers. */
+ if (timestamp.tv_nsec != 0 && timestamp.tv_sec < TYPE_MAXIMUM (time_t))
+ timestamp = make_timespec (timestamp.tv_sec + 1, 0);
+#elif defined (HAVE_CLOCK_GETRES)
+ /* Check that the system clock is precise enough. If
+ not, round TIME up to the system clock resolution. */
+ if (timespec_valid_p (resolution)
+ && timespec_cmp (timestamp, resolution) < 0)
+ timestamp = resolution;
#endif /* not HAVE_SETITIMER */
/* Get an atimer structure from the free-list, or allocate
free_atimers = t->next;
}
else
- t = (struct atimer *) xmalloc (sizeof *t);
+ t = xmalloc (sizeof *t);
/* Fill the atimer structure. */
memset (t, 0, sizeof *t);
t->fn = fn;
t->client_data = client_data;
- BLOCK_ATIMERS;
+ block_atimers (&oldset);
/* Compute the timer's expiration time. */
switch (type)
break;
case ATIMER_RELATIVE:
- EMACS_GET_TIME (t->expiration);
- EMACS_ADD_TIME (t->expiration, t->expiration, timestamp);
+ t->expiration = timespec_add (current_timespec (), timestamp);
break;
case ATIMER_CONTINUOUS:
- EMACS_GET_TIME (t->expiration);
- EMACS_ADD_TIME (t->expiration, t->expiration, timestamp);
+ t->expiration = timespec_add (current_timespec (), timestamp);
t->interval = timestamp;
break;
}
/* Insert the timer in the list of active atimers. */
schedule_atimer (t);
- UNBLOCK_ATIMERS;
+ unblock_atimers (&oldset);
/* Arrange for a SIGALRM at the time the next atimer is ripe. */
set_alarm ();
cancel_atimer (struct atimer *timer)
{
int i;
+ sigset_t oldset;
- BLOCK_ATIMERS;
+ block_atimers (&oldset);
for (i = 0; i < 2; ++i)
{
}
}
- UNBLOCK_ATIMERS;
+ unblock_atimers (&oldset);
}
void
stop_other_atimers (struct atimer *t)
{
- BLOCK_ATIMERS;
+ sigset_t oldset;
+ block_atimers (&oldset);
if (t)
{
stopped_atimers = append_atimer_lists (atimers, stopped_atimers);
atimers = t;
- UNBLOCK_ATIMERS;
+ unblock_atimers (&oldset);
}
/* Run all timers again, if some have been stopped with a call to
stop_other_atimers. */
-static void
+void
run_all_atimers (void)
{
if (stopped_atimers)
{
struct atimer *t = atimers;
struct atimer *next;
+ sigset_t oldset;
- BLOCK_ATIMERS;
+ block_atimers (&oldset);
atimers = stopped_atimers;
stopped_atimers = NULL;
t = next;
}
- UNBLOCK_ATIMERS;
+ unblock_atimers (&oldset);
}
}
-/* A version of run_all_atimers suitable for a record_unwind_protect. */
-
-Lisp_Object
-unwind_stop_other_atimers (Lisp_Object dummy)
-{
- run_all_atimers ();
- return Qnil;
-}
-
-
/* Arrange for a SIGALRM to arrive when the next timer is ripe. */
static void
{
if (atimers)
{
- EMACS_TIME now, timestamp;
#ifdef HAVE_SETITIMER
struct itimerval it;
#endif
+ struct timespec now, interval;
- /* Determine s/us till the next timer is ripe. */
- EMACS_GET_TIME (now);
-
- /* Don't set the interval to 0; this disables the timer. */
- if (EMACS_TIME_LE (atimers->expiration, now))
+#if defined (HAVE_TIMERFD) || defined (HAVE_ITIMERSPEC)
+ if (special_timer_available)
{
- EMACS_SET_SECS (timestamp, 0);
- EMACS_SET_USECS (timestamp, 1000);
+ struct itimerspec ispec;
+ ispec.it_value = atimers->expiration;
+ ispec.it_interval.tv_sec = ispec.it_interval.tv_nsec = 0;
+#if defined (HAVE_TIMERFD)
+ if (special_timer_available == 1)
+ {
+ add_timer_wait_descriptor (timerfd);
+ special_timer_available++;
+ }
+ if (timerfd_settime (timerfd, TFD_TIMER_ABSTIME, &ispec, 0) == 0)
+#elif defined (HAVE_ITIMERSPEC)
+ if (timer_settime (alarm_timer, TIMER_ABSTIME, &ispec, 0) == 0)
+#endif
+ return;
}
- else
- EMACS_SUB_TIME (timestamp, atimers->expiration, now);
+#endif /* HAVE_TIMERFD || HAVE_ITIMERSPEC */
+ /* Determine interval till the next timer is ripe.
+ Don't set the interval to 0; this disables the timer. */
+ now = current_timespec ();
+ interval = (timespec_cmp (atimers->expiration, now) <= 0
+ ? make_timespec (0, 1000 * 1000)
+ : timespec_sub (atimers->expiration, now));
#ifdef HAVE_SETITIMER
memset (&it, 0, sizeof it);
- it.it_value = make_timeval (timestamp);
+ it.it_value = make_timeval (interval);
setitimer (ITIMER_REAL, &it, 0);
#else /* not HAVE_SETITIMER */
- alarm (max (EMACS_SECS (timestamp), 1));
+ alarm (max (interval.tv_sec, 1));
#endif /* not HAVE_SETITIMER */
}
}
struct atimer *a = atimers, *prev = NULL;
/* Look for the first atimer that is ripe after T. */
- while (a && EMACS_TIME_GT (t->expiration, a->expiration))
+ while (a && timespec_cmp (a->expiration, t->expiration) < 0)
prev = a, a = a->next;
/* Insert T in front of the atimer found, if any. */
static void
run_timers (void)
{
- EMACS_TIME now;
+ struct timespec now = current_timespec ();
- while (atimers
- && (pending_atimers = interrupt_input_blocked) == 0
- && (EMACS_GET_TIME (now),
- EMACS_TIME_LE (atimers->expiration, now)))
+ while (atimers && timespec_cmp (atimers->expiration, now) <= 0)
{
- struct atimer *t;
-
- t = atimers;
+ struct atimer *t = atimers;
atimers = atimers->next;
t->fn (t);
if (t->type == ATIMER_CONTINUOUS)
{
- EMACS_ADD_TIME (t->expiration, now, t->interval);
+ t->expiration = timespec_add (now, t->interval);
schedule_atimer (t);
}
else
}
}
- if (! atimers)
- pending_atimers = 0;
-
-#ifdef SYNC_INPUT
- if (pending_atimers)
- pending_signals = 1;
- else
- {
- pending_signals = interrupt_input_pending;
- set_alarm ();
- }
-#else
- if (! pending_atimers)
- set_alarm ();
-#endif
+ set_alarm ();
}
/* Signal handler for SIGALRM. SIGNO is the signal number, i.e.
SIGALRM. */
-void
-alarm_signal_handler (int signo)
+static void
+handle_alarm_signal (int sig)
{
-#ifndef SYNC_INPUT
- SIGNAL_THREAD_CHECK (signo);
-#endif
-
- pending_atimers = 1;
-#ifdef SYNC_INPUT
pending_signals = 1;
-#else
- run_timers ();
-#endif
}
+#ifdef HAVE_TIMERFD
+
+/* Called from wait_reading_process_output when FD, which
+ should be equal to TIMERFD, is available for reading. */
+
+void
+timerfd_callback (int fd, void *arg)
+{
+ char buf[8];
+ ptrdiff_t nbytes;
+
+ eassert (fd == timerfd);
+ nbytes = emacs_read (fd, buf, sizeof (buf));
+ /* Just discard an expiration count for now. */
+ eassert (nbytes == sizeof (buf));
+ do_pending_atimers ();
+}
+
+#endif /* HAVE_TIMERFD */
-/* Call alarm_signal_handler for pending timers. */
+/* Do pending timers. */
void
do_pending_atimers (void)
{
- if (pending_atimers)
+ if (atimers)
{
- BLOCK_ATIMERS;
+ sigset_t oldset;
+ block_atimers (&oldset);
run_timers ();
- UNBLOCK_ATIMERS;
+ unblock_atimers (&oldset);
}
}
some systems like HPUX (see process.c). */
void
-turn_on_atimers (int on)
+turn_on_atimers (bool on)
{
if (on)
+ set_alarm ();
+ else
{
- signal (SIGALRM, alarm_signal_handler);
- set_alarm ();
+#ifdef HAVE_TIMERFD
+ if (special_timer_available > 1)
+ {
+ struct itimerspec ispec;
+ memset (&ispec, 0, sizeof (ispec));
+ /* Writing zero expiration time should disarm it. */
+ timerfd_settime (timerfd, TFD_TIMER_ABSTIME, &ispec, 0);
+ }
+#endif /* HAVE_TIMERFD */
+ alarm (0);
}
- else
- alarm (0);
}
+/* This is intended to use from automated tests. */
+
+#ifdef ENABLE_CHECKING
+
+#define MAXTIMERS 10
+
+struct atimer_result
+{
+ /* Time when we expect this timer to trigger. */
+ struct timespec expected;
+
+ /* Timer status: -1 if not triggered, 0 if triggered
+ too early or too late, 1 if triggered timely. */
+ int intime;
+};
+
+static void
+debug_timer_callback (struct atimer *t)
+{
+ struct timespec now = current_timespec ();
+ struct atimer_result *r = (struct atimer_result *) t->client_data;
+ int result = timespec_cmp (now, r->expected);
+
+ if (result < 0)
+ /* Too early. */
+ r->intime = 0;
+ else if (result >= 0)
+ {
+#ifdef HAVE_SETITIMER
+ struct timespec delta = timespec_sub (now, r->expected);
+ /* Too late if later than expected + 0.01s. FIXME:
+ this should depend from system clock resolution. */
+ if (timespec_cmp (delta, make_timespec (0, 10000000)) > 0)
+ r->intime = 0;
+ else
+#endif /* HAVE_SETITIMER */
+ r->intime = 1;
+ }
+}
+
+DEFUN ("debug-timer-check", Fdebug_timer_check, Sdebug_timer_check, 0, 0, 0,
+ doc: /* Run internal self-tests to check timers subsystem.
+Return t if all self-tests are passed, nil otherwise. */)
+ (void)
+{
+ int i, ok;
+ struct atimer *timer;
+ struct atimer_result *results[MAXTIMERS];
+ struct timespec t = make_timespec (0, 0);
+
+ /* Arm MAXTIMERS relative timers to trigger with 0.1s intervals. */
+ for (i = 0; i < MAXTIMERS; i++)
+ {
+ results[i] = xmalloc (sizeof (struct atimer_result));
+ t = timespec_add (t, make_timespec (0, 100000000));
+ results[i]->expected = timespec_add (current_timespec (), t);
+ results[i]->intime = -1;
+ timer = start_atimer (ATIMER_RELATIVE, t,
+ debug_timer_callback, results[i]);
+ }
+
+ /* Wait for 1s but process timers. */
+ wait_reading_process_output (1, 0, 0, false, Qnil, NULL, 0);
+ /* Shut up the compiler by "using" this variable. */
+ (void) timer;
+
+ for (i = 0, ok = 0; i < MAXTIMERS; i++)
+ ok += results[i]->intime, xfree (results[i]);
+
+ return ok == MAXTIMERS ? Qt : Qnil;
+}
+
+#endif /* ENABLE_CHECKING */
void
init_atimer (void)
{
+#if defined (HAVE_TIMERFD)
+ timerfd = timerfd_create (CLOCK_REALTIME, TIMERFD_CREATE_FLAGS);
+ special_timer_available = !!(timerfd != -1);
+#elif defined (HAVE_ITIMERSPEC)
+ struct sigevent sigev;
+ sigev.sigev_notify = SIGEV_SIGNAL;
+ sigev.sigev_signo = SIGALRM;
+ sigev.sigev_value.sival_ptr = &alarm_timer;
+ special_timer_available
+ = timer_create (CLOCK_REALTIME, &sigev, &alarm_timer) == 0;
+#endif /* HAVE_TIMERFD */
+#ifdef HAVE_CLOCK_GETRES
+ if (clock_getres (CLOCK_REALTIME, &resolution))
+ resolution = invalid_timespec ();
+#endif
free_atimers = stopped_atimers = atimers = NULL;
- pending_atimers = 0;
- /* pending_signals is initialized in init_keyboard.*/
- signal (SIGALRM, alarm_signal_handler);
+
+ /* pending_signals is initialized in init_keyboard. */
+ struct sigaction action;
+ emacs_sigaction_init (&action, handle_alarm_signal);
+ sigaction (SIGALRM, &action, 0);
+
+#ifdef ENABLE_CHECKING
+ defsubr (&Sdebug_timer_check);
+#endif
}