auto import from //depot/cupcake/@135843
diff --git a/libc/bionic/pthread-timers.c b/libc/bionic/pthread-timers.c
new file mode 100644
index 0000000..7b9c99e
--- /dev/null
+++ b/libc/bionic/pthread-timers.c
@@ -0,0 +1,639 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include "pthread_internal.h"
+#include <linux/time.h>
+#include <string.h>
+#include <errno.h>
+
+/* This file implements the support required to implement SIGEV_THREAD posix
+ * timers. See the following pages for additionnal details:
+ *
+ * www.opengroup.org/onlinepubs/000095399/functions/timer_create.html
+ * www.opengroup.org/onlinepubs/000095399/functions/timer_settime.html
+ * www.opengroup.org/onlinepubs/000095399/functions/xsh_chap02_04.html#tag_02_04_01
+ *
+ * The Linux kernel doesn't support these, so we need to implement them in the
+ * C library. We use a very basic scheme where each timer is associated to a
+ * thread that will loop, waiting for timeouts or messages from the program
+ * corresponding to calls to timer_settime() and timer_delete().
+ *
+ * Note also an important thing: Posix mandates that in the case of fork(),
+ * the timers of the child process should be disarmed, but not deleted.
+ * this is implemented by providing a fork() wrapper (see bionic/fork.c) which
+ * stops all timers before the fork, and only re-start them in case of error
+ * or in the parent process.
+ *
+ * the stop/start is implemented by the __timer_table_start_stop() function
+ * below.
+ */
+
+/* normal (i.e. non-SIGEV_THREAD) timer ids are created directly by the kernel
+ * and are passed as is to/from the caller.
+ *
+ * on the other hand, a SIGEV_THREAD timer ID will have its TIMER_ID_WRAP_BIT
+ * always set to 1. In this implementation, this is always bit 31, which is
+ * guaranteed to never be used by kernel-provided timer ids
+ *
+ * (see code in <kernel>/lib/idr.c, used to manage IDs, to see why)
+ */
+
+#define TIMER_ID_WRAP_BIT 0x80000000
+#define TIMER_ID_WRAP(id) ((timer_t)((id) | TIMER_ID_WRAP_BIT))
+#define TIMER_ID_UNWRAP(id) ((timer_t)((id) & ~TIMER_ID_WRAP_BIT))
+#define TIMER_ID_IS_WRAPPED(id) (((id) & TIMER_ID_WRAP_BIT) != 0)
+
+/* this value is used internally to indicate a 'free' or 'zombie'
+ * thr_timer structure. Here, 'zombie' means that timer_delete()
+ * has been called, but that the corresponding thread hasn't
+ * exited yet.
+ */
+#define TIMER_ID_NONE ((timer_t)0xffffffff)
+
+/* True iff a timer id is valid */
+#define TIMER_ID_IS_VALID(id) ((id) != TIMER_ID_NONE)
+
+/* the maximum value of overrun counters */
+#define DELAYTIMER_MAX 0x7fffffff
+
+#define __likely(x) __builtin_expect(!!(x),1)
+#define __unlikely(x) __builtin_expect(!!(x),0)
+
+typedef struct thr_timer thr_timer_t;
+typedef struct thr_timer_table thr_timer_table_t;
+
+/* The Posix spec says the function receives an unsigned parameter, but
+ * it's really a 'union sigval' a.k.a. sigval_t */
+typedef void (*thr_timer_func_t)( sigval_t );
+
+struct thr_timer {
+ thr_timer_t* next; /* next in free list */
+ timer_t id; /* TIMER_ID_NONE iff free or dying */
+ clockid_t clock;
+ pthread_t thread;
+ pthread_attr_t attributes;
+ thr_timer_func_t callback;
+ sigval_t value;
+
+ /* the following are used to communicate between
+ * the timer thread and the timer_XXX() functions
+ */
+ pthread_mutex_t mutex; /* lock */
+ pthread_cond_t cond; /* signal a state change to thread */
+ int volatile done; /* set by timer_delete */
+ int volatile stopped; /* set by _start_stop() */
+ struct timespec volatile expires; /* next expiration time, or 0 */
+ struct timespec volatile period; /* reload value, or 0 */
+ int volatile overruns; /* current number of overruns */
+};
+
+#define MAX_THREAD_TIMERS 32
+
+struct thr_timer_table {
+ pthread_mutex_t lock;
+ thr_timer_t* free_timer;
+ thr_timer_t timers[ MAX_THREAD_TIMERS ];
+};
+
+/** GLOBAL TABLE OF THREAD TIMERS
+ **/
+
+static void
+thr_timer_table_init( thr_timer_table_t* t )
+{
+ int nn;
+
+ memset(t, 0, sizeof *t);
+ pthread_mutex_init( &t->lock, NULL );
+
+ for (nn = 0; nn < MAX_THREAD_TIMERS; nn++)
+ t->timers[nn].id = TIMER_ID_NONE;
+
+ t->free_timer = &t->timers[0];
+ for (nn = 1; nn < MAX_THREAD_TIMERS; nn++)
+ t->timers[nn-1].next = &t->timers[nn];
+}
+
+
+static thr_timer_t*
+thr_timer_table_alloc( thr_timer_table_t* t )
+{
+ thr_timer_t* timer;
+
+ if (t == NULL)
+ return NULL;
+
+ pthread_mutex_lock(&t->lock);
+ timer = t->free_timer;
+ if (timer != NULL) {
+ t->free_timer = timer->next;
+ timer->next = NULL;
+ timer->id = TIMER_ID_WRAP((timer - t->timers));
+ }
+ pthread_mutex_unlock(&t->lock);
+ return timer;
+}
+
+
+static void
+thr_timer_table_free( thr_timer_table_t* t, thr_timer_t* timer )
+{
+ pthread_mutex_lock( &t->lock );
+ timer->id = TIMER_ID_NONE;
+ timer->thread = 0;
+ timer->next = t->free_timer;
+ t->free_timer = timer;
+ pthread_mutex_unlock( &t->lock );
+}
+
+
+static void
+thr_timer_table_start_stop( thr_timer_table_t* t, int stop )
+{
+ int nn;
+
+ pthread_mutex_lock(&t->lock);
+
+ for (nn = 0; nn < MAX_THREAD_TIMERS; nn++) {
+ thr_timer_t* timer = &t->timers[nn];
+
+ if (TIMER_ID_IS_VALID(timer->id)) {
+ /* tell the thread to start/stop */
+ pthread_mutex_lock(&timer->mutex);
+ timer->stopped = stop;
+ pthread_cond_signal( &timer->cond );
+ pthread_mutex_unlock(&timer->mutex);
+ }
+ }
+ pthread_mutex_unlock(&t->lock);
+}
+
+
+/* convert a timer_id into the corresponding thr_timer_t* pointer
+ * returns NULL if the id is not wrapped or is invalid/free
+ */
+static thr_timer_t*
+thr_timer_table_from_id( thr_timer_table_t* t,
+ timer_t id,
+ int remove )
+{
+ unsigned index;
+ thr_timer_t* timer;
+
+ if (t == NULL || !TIMER_ID_IS_WRAPPED(id))
+ return NULL;
+
+ index = (unsigned) TIMER_ID_UNWRAP(id);
+ if (index >= MAX_THREAD_TIMERS)
+ return NULL;
+
+ pthread_mutex_lock(&t->lock);
+
+ timer = &t->timers[index];
+
+ if (!TIMER_ID_IS_VALID(timer->id)) {
+ timer = NULL;
+ } else {
+ /* if we're removing this timer, clear the id
+ * right now to prevent another thread to
+ * use the same id after the unlock */
+ if (remove)
+ timer->id = TIMER_ID_NONE;
+ }
+ pthread_mutex_unlock(&t->lock);
+
+ return timer;
+}
+
+/* the static timer table - we only create it if the process
+ * really wants to use SIGEV_THREAD timers, which should be
+ * pretty infrequent
+ */
+
+static pthread_once_t __timer_table_once = PTHREAD_ONCE_INIT;
+static thr_timer_table_t* __timer_table;
+
+static void
+__timer_table_init( void )
+{
+ __timer_table = calloc(1,sizeof(*__timer_table));
+
+ if (__timer_table != NULL)
+ thr_timer_table_init( __timer_table );
+}
+
+static thr_timer_table_t*
+__timer_table_get(void)
+{
+ pthread_once( &__timer_table_once, __timer_table_init );
+ return __timer_table;
+}
+
+/** POSIX THREAD TIMERS CLEANUP ON FORK
+ **
+ ** this should be called from the 'fork()' wrapper to stop/start
+ ** all active thread timers. this is used to implement a Posix
+ ** requirements: the timers of fork child processes must be
+ ** disarmed but not deleted.
+ **/
+void
+__timer_table_start_stop( int stop )
+{
+ if (__timer_table != NULL) {
+ thr_timer_table_t* table = __timer_table_get();
+ thr_timer_table_start_stop(table, stop);
+ }
+}
+
+static thr_timer_t*
+thr_timer_from_id( timer_t id )
+{
+ thr_timer_table_t* table = __timer_table_get();
+ thr_timer_t* timer = thr_timer_table_from_id( table, id, 0 );
+
+ return timer;
+}
+
+
+static __inline__ void
+thr_timer_lock( thr_timer_t* t )
+{
+ pthread_mutex_lock(&t->mutex);
+}
+
+static __inline__ void
+thr_timer_unlock( thr_timer_t* t )
+{
+ pthread_mutex_unlock(&t->mutex);
+}
+
+/** POSIX TIMERS APIs */
+
+/* first, declare the syscall stubs */
+extern int __timer_create( clockid_t, struct sigevent*, timer_t* );
+extern int __timer_delete( timer_t );
+extern int __timer_gettime( timer_t, struct itimerspec* );
+extern int __timer_settime( timer_t, int, const struct itimerspec*, struct itimerspec* );
+extern int __timer_getoverrun(timer_t);
+
+static void* timer_thread_start( void* );
+
+/* then the wrappers themselves */
+int
+timer_create( clockid_t clockid, struct sigevent* evp, timer_t *ptimerid)
+{
+ /* if not a SIGEV_THREAD timer, direct creation by the kernel */
+ if (__likely(evp == NULL || evp->sigev_notify != SIGEV_THREAD))
+ return __timer_create( clockid, evp, ptimerid );
+
+ // check arguments
+ if (evp->sigev_notify_function == NULL) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ {
+ struct timespec dummy;
+
+ /* check that the clock id is supported by the kernel */
+ if (clock_gettime( clockid, &dummy ) < 0 && errno == EINVAL )
+ return -1;
+ }
+
+ /* create a new timer and its thread */
+ {
+ thr_timer_table_t* table = __timer_table_get();
+ thr_timer_t* timer = thr_timer_table_alloc( table );
+ struct sigevent evp0;
+
+ if (timer == NULL) {
+ errno = ENOMEM;
+ return -1;
+ }
+
+ /* copy the thread attributes */
+ if (evp->sigev_notify_attributes == NULL) {
+ pthread_attr_init(&timer->attributes);
+ }
+ else {
+ timer->attributes = ((pthread_attr_t*)evp->sigev_notify_attributes)[0];
+ }
+
+ /* Posix says that the default is PTHREAD_CREATE_DETACHED and
+ * that PTHREAD_CREATE_JOINABLE has undefined behaviour.
+ * So simply always use DETACHED :-)
+ */
+ pthread_attr_setdetachstate(&timer->attributes, PTHREAD_CREATE_DETACHED);
+
+ timer->callback = evp->sigev_notify_function;
+ timer->value = evp->sigev_value;
+ timer->clock = clockid;
+
+ pthread_mutex_init( &timer->mutex, NULL );
+ pthread_cond_init( &timer->cond, NULL );
+
+ timer->done = 0;
+ timer->stopped = 0;
+ timer->expires.tv_sec = timer->expires.tv_nsec = 0;
+ timer->period.tv_sec = timer->period.tv_nsec = 0;
+ timer->overruns = 0;
+
+ /* create the thread */
+ if (pthread_create( &timer->thread, &timer->attributes, timer_thread_start, timer ) < 0) {
+ thr_timer_table_free( __timer_table, timer );
+ errno = ENOMEM;
+ return -1;
+ }
+
+ *ptimerid = timer->id;
+ return 0;
+ }
+}
+
+
+int
+timer_delete( timer_t id )
+{
+ if ( __likely(!TIMER_ID_IS_WRAPPED(id)) )
+ return __timer_delete( id );
+ else
+ {
+ thr_timer_table_t* table = __timer_table_get();
+ thr_timer_t* timer = thr_timer_table_from_id(table, id, 1);
+
+ if (timer == NULL) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* tell the timer's thread to stop */
+ thr_timer_lock(timer);
+ timer->done = 1;
+ pthread_cond_signal( &timer->cond );
+ thr_timer_unlock(timer);
+
+ /* NOTE: the thread will call __timer_table_free() to free the
+ * timer object. the '1' parameter to thr_timer_table_from_id
+ * above ensured that the object and its timer_id cannot be
+ * reused before that.
+ */
+ return 0;
+ }
+}
+
+/* return the relative time until the next expiration, or 0 if
+ * the timer is disarmed */
+static void
+timer_gettime_internal( thr_timer_t* timer,
+ struct itimerspec* spec)
+{
+ struct timespec diff;
+
+ diff = timer->expires;
+ if (!timespec_is_zero(&diff))
+ {
+ struct timespec now;
+
+ clock_gettime( timer->clock, &now );
+ timespec_sub(&diff, &now);
+
+ /* in case of overrun, return 0 */
+ if (timespec_cmp0(&diff) < 0) {
+ timespec_zero(&diff);
+ }
+ }
+
+ spec->it_value = diff;
+ spec->it_interval = timer->period;
+}
+
+
+int
+timer_gettime( timer_t id, struct itimerspec* ospec )
+{
+ if (ospec == NULL) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ if ( __likely(!TIMER_ID_IS_WRAPPED(id)) ) {
+ return __timer_gettime( id, ospec );
+ } else {
+ thr_timer_t* timer = thr_timer_from_id(id);
+
+ if (timer == NULL) {
+ errno = EINVAL;
+ return -1;
+ }
+ thr_timer_lock(timer);
+ timer_gettime_internal( timer, ospec );
+ thr_timer_unlock(timer);
+ }
+ return 0;
+}
+
+
+int
+timer_settime( timer_t id,
+ int flags,
+ const struct itimerspec* spec,
+ struct itimerspec* ospec )
+{
+ if (spec == NULL) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ if ( __likely(!TIMER_ID_IS_WRAPPED(id)) ) {
+ return __timer_settime( id, flags, spec, ospec );
+ } else {
+ thr_timer_t* timer = thr_timer_from_id(id);
+ struct timespec expires, now;
+
+ if (timer == NULL) {
+ errno = EINVAL;
+ return -1;
+ }
+ thr_timer_lock(timer);
+
+ /* return current timer value if ospec isn't NULL */
+ if (ospec != NULL) {
+ timer_gettime_internal(timer, ospec );
+ }
+
+ /* compute next expiration time. note that if the
+ * new it_interval is 0, we should disarm the timer
+ */
+ expires = spec->it_value;
+ if (!timespec_is_zero(&expires)) {
+ clock_gettime( timer->clock, &now );
+ if (!(flags & TIMER_ABSTIME)) {
+ timespec_add(&expires, &now);
+ } else {
+ if (timespec_cmp(&expires, &now) < 0)
+ expires = now;
+ }
+ }
+ timer->expires = expires;
+ timer->period = spec->it_interval;
+ thr_timer_unlock( timer );
+
+ /* signal the change to the thread */
+ pthread_cond_signal( &timer->cond );
+ }
+ return 0;
+}
+
+
+int
+timer_getoverrun(timer_t id)
+{
+ if ( __likely(!TIMER_ID_IS_WRAPPED(id)) ) {
+ return __timer_getoverrun( id );
+ } else {
+ thr_timer_t* timer = thr_timer_from_id(id);
+ int result;
+
+ if (timer == NULL) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ thr_timer_lock(timer);
+ result = timer->overruns;
+ thr_timer_unlock(timer);
+
+ return result;
+ }
+}
+
+
+static void*
+timer_thread_start( void* _arg )
+{
+ thr_timer_t* timer = _arg;
+
+ thr_timer_lock( timer );
+
+ /* we loop until timer->done is set in timer_delete() */
+ while (!timer->done)
+ {
+ struct timespec expires = timer->expires;
+ struct timespec period = timer->period;
+ struct timespec now;
+
+ /* if the timer is stopped or disarmed, wait indefinitely
+ * for a state change from timer_settime/_delete/_start_stop
+ */
+ if ( timer->stopped || timespec_is_zero(&expires) )
+ {
+ pthread_cond_wait( &timer->cond, &timer->mutex );
+ continue;
+ }
+
+ /* otherwise, we need to do a timed wait until either a
+ * state change of the timer expiration time.
+ */
+ clock_gettime(timer->clock, &now);
+
+ if (timespec_cmp( &expires, &now ) > 0)
+ {
+ /* cool, there was no overrun, so compute the
+ * relative timeout as 'expires - now', then wait
+ */
+ int ret;
+ struct timespec diff = expires;
+ timespec_sub( &diff, &now );
+
+ ret = __pthread_cond_timedwait_relative(
+ &timer->cond, &timer->mutex, &diff);
+
+ /* if we didn't timeout, it means that a state change
+ * occured, so reloop to take care of it.
+ */
+ if (ret != ETIMEDOUT)
+ continue;
+ }
+ else
+ {
+ /* overrun was detected before we could wait ! */
+ if (!timespec_is_zero( &period ) )
+ {
+ /* for periodic timers, compute total overrun count */
+ do {
+ timespec_add( &expires, &period );
+ if (timer->overruns < DELAYTIMER_MAX)
+ timer->overruns += 1;
+ } while ( timespec_cmp( &expires, &now ) < 0 );
+
+ /* backtrack the last one, because we're going to
+ * add the same value just a bit later */
+ timespec_sub( &expires, &period );
+ }
+ else
+ {
+ /* for non-periodic timer, things are simple */
+ timer->overruns = 1;
+ }
+ }
+
+ /* if we get there, a timeout was detected.
+ * first reload/disarm the timer has needed
+ */
+ if ( !timespec_is_zero(&period) ) {
+ timespec_add( &expires, &period );
+ } else {
+ timespec_zero( &expires );
+ }
+ timer->expires = expires;
+
+ /* now call the timer callback function. release the
+ * lock to allow the function to modify the timer setting
+ * or call timer_getoverrun().
+ *
+ * NOTE: at this point we trust the callback not to be a
+ * total moron and pthread_kill() the timer thread
+ */
+ thr_timer_unlock(timer);
+ timer->callback( timer->value );
+ thr_timer_lock(timer);
+
+ /* now clear the overruns counter. it only makes sense
+ * within the callback */
+ timer->overruns = 0;
+ }
+
+ thr_timer_unlock( timer );
+
+ /* free the timer object now. there is no need to call
+ * __timer_table_get() since we're guaranteed that __timer_table
+ * is initialized in this thread
+ */
+ thr_timer_table_free(__timer_table, timer);
+
+ return NULL;
+}