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-rw-r--r--lib/libc/gen/sem_new.c470
1 files changed, 470 insertions, 0 deletions
diff --git a/lib/libc/gen/sem_new.c b/lib/libc/gen/sem_new.c
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index 0000000..dac5381
--- /dev/null
+++ b/lib/libc/gen/sem_new.c
@@ -0,0 +1,470 @@
+/*
+ * Copyright (C) 2010 David Xu <davidxu@freebsd.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice(s), this list of conditions and the following disclaimer as
+ * the first lines of this file unmodified other than the possible
+ * addition of one or more copyright notices.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice(s), 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 HOLDER(S) ``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 HOLDER(S) 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.
+ *
+ * $FreeBSD$
+ */
+
+#include "namespace.h"
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <machine/atomic.h>
+#include <sys/umtx.h>
+#include <limits.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <semaphore.h>
+#include <unistd.h>
+#include "un-namespace.h"
+
+__weak_reference(_libc_sem_close, sem_close);
+__weak_reference(_libc_sem_close, _sem_close);
+__weak_reference(_libc_sem_destroy, sem_destroy);
+__weak_reference(_libc_sem_destroy, _sem_destroy);
+__weak_reference(_libc_sem_getvalue, sem_getvalue);
+__weak_reference(_libc_sem_getvalue, _sem_getvalue);
+__weak_reference(_libc_sem_init, sem_init);
+__weak_reference(_libc_sem_init, _sem_init);
+__weak_reference(_libc_sem_open, sem_open);
+__weak_reference(_libc_sem_open, _sem_open);
+__weak_reference(_libc_sem_post, sem_post);
+__weak_reference(_libc_sem_post, _sem_post);
+__weak_reference(_libc_sem_timedwait, sem_timedwait);
+__weak_reference(_libc_sem_timedwait, _sem_timedwait);
+__weak_reference(_libc_sem_trywait, sem_trywait);
+__weak_reference(_libc_sem_trywait, _sem_trywait);
+__weak_reference(_libc_sem_unlink, sem_unlink);
+__weak_reference(_libc_sem_unlink, _sem_unlink);
+__weak_reference(_libc_sem_wait, sem_wait);
+__weak_reference(_libc_sem_wait, _sem_wait);
+
+#define SEM_PREFIX "/tmp/SEMD"
+#define SEM_MAGIC ((u_int32_t)0x73656d31)
+
+struct sem_nameinfo {
+ int open_count;
+ char *name;
+ sem_t *sem;
+ LIST_ENTRY(sem_nameinfo) next;
+};
+
+static pthread_once_t once = PTHREAD_ONCE_INIT;
+static pthread_mutex_t sem_llock;
+static LIST_HEAD(,sem_nameinfo) sem_list = LIST_HEAD_INITIALIZER(sem_list);
+
+static void
+sem_prefork()
+{
+
+ _pthread_mutex_lock(&sem_llock);
+}
+
+static void
+sem_postfork()
+{
+ _pthread_mutex_unlock(&sem_llock);
+}
+
+static void
+sem_child_postfork()
+{
+ _pthread_mutex_unlock(&sem_llock);
+}
+
+static void
+sem_module_init(void)
+{
+ pthread_mutexattr_t ma;
+
+ _pthread_mutexattr_init(&ma);
+ _pthread_mutexattr_settype(&ma, PTHREAD_MUTEX_RECURSIVE);
+ _pthread_mutex_init(&sem_llock, &ma);
+ _pthread_mutexattr_destroy(&ma);
+ _pthread_atfork(sem_prefork, sem_postfork, sem_child_postfork);
+}
+
+static inline int
+sem_check_validity(sem_t *sem)
+{
+
+ if (sem->_magic == SEM_MAGIC)
+ return (0);
+ else {
+ errno = EINVAL;
+ return (-1);
+ }
+}
+
+int
+_libc_sem_init(sem_t *sem, int pshared, unsigned int value)
+{
+
+ if (value > SEM_VALUE_MAX) {
+ errno = EINVAL;
+ return (-1);
+ }
+
+ bzero(sem, sizeof(sem_t));
+ sem->_magic = SEM_MAGIC;
+ sem->_kern._count = (u_int32_t)value;
+ sem->_kern._has_waiters = 0;
+ sem->_kern._flags = pshared ? USYNC_PROCESS_SHARED : 0;
+ return (0);
+}
+
+sem_t *
+_libc_sem_open(const char *name, int flags, ...)
+{
+ char path[PATH_MAX];
+
+ struct stat sb;
+ va_list ap;
+ struct sem_nameinfo *ni = NULL;
+ sem_t *sem = NULL;
+ int fd = -1, mode, len;
+
+ if (name[0] != '/') {
+ errno = EINVAL;
+ return (NULL);
+ }
+ name++;
+
+ if (flags & ~(O_CREAT|O_EXCL)) {
+ errno = EINVAL;
+ return (NULL);
+ }
+
+ _pthread_once(&once, sem_module_init);
+
+ _pthread_mutex_lock(&sem_llock);
+ LIST_FOREACH(ni, &sem_list, next) {
+ if (strcmp(name, ni->name) == 0) {
+ ni->open_count++;
+ sem = ni->sem;
+ _pthread_mutex_unlock(&sem_llock);
+ return (sem);
+ }
+ }
+
+ if (flags & O_CREAT) {
+ va_start(ap, flags);
+ mode = va_arg(ap, int);
+ va_end(ap);
+ }
+
+ len = sizeof(*ni) + strlen(name) + 1;
+ ni = (struct sem_nameinfo *)malloc(len);
+ if (ni == NULL) {
+ errno = ENOSPC;
+ goto error;
+ }
+
+ ni->name = (char *)(ni+1);
+ strcpy(ni->name, name);
+
+ strcpy(path, SEM_PREFIX);
+ if (strlcat(path, name, sizeof(path)) >= sizeof(path)) {
+ errno = ENAMETOOLONG;
+ goto error;
+ }
+
+ fd = _open(path, flags|O_RDWR, mode);
+ if (fd == -1)
+ goto error;
+ if (flock(fd, LOCK_EX) == -1)
+ goto error;
+ if (_fstat(fd, &sb)) {
+ flock(fd, LOCK_UN);
+ goto error;
+ }
+ if (sb.st_size < sizeof(sem_t)) {
+ sem_t tmp;
+
+ tmp._magic = SEM_MAGIC;
+ tmp._kern._has_waiters = 0;
+ tmp._kern._count = 0;
+ tmp._kern._flags = USYNC_PROCESS_SHARED | SEM_NAMED;
+ if (_write(fd, &tmp, sizeof(tmp)) != sizeof(tmp)) {
+ flock(fd, LOCK_UN);
+ goto error;
+ }
+ }
+ flock(fd, LOCK_UN);
+ sem = (sem_t *)mmap(NULL, sizeof(sem_t), PROT_READ|PROT_WRITE,
+ MAP_SHARED|MAP_NOSYNC, fd, 0);
+ if (sem == MAP_FAILED) {
+ sem = NULL;
+ if (errno == ENOMEM)
+ errno = ENOSPC;
+ goto error;
+ }
+ if (sem->_magic != SEM_MAGIC) {
+ errno = EINVAL;
+ goto error;
+ }
+ ni->open_count = 1;
+ ni->sem = sem;
+ LIST_INSERT_HEAD(&sem_list, ni, next);
+ _pthread_mutex_unlock(&sem_llock);
+ _close(fd);
+ return (sem);
+
+error:
+ _pthread_mutex_unlock(&sem_llock);
+ if (fd != -1)
+ _close(fd);
+ if (sem != NULL)
+ munmap(sem, sizeof(sem_t));
+ free(ni);
+ return (SEM_FAILED);
+}
+
+int
+_libc_sem_close(sem_t *sem)
+{
+ struct sem_nameinfo *ni;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ if (!(sem->_kern._flags & SEM_NAMED)) {
+ errno = EINVAL;
+ return (-1);
+ }
+
+ _pthread_mutex_lock(&sem_llock);
+ LIST_FOREACH(ni, &sem_list, next) {
+ if (sem == ni->sem) {
+ if (--ni->open_count > 0) {
+ _pthread_mutex_unlock(&sem_llock);
+ return (0);
+ }
+ else
+ break;
+ }
+ }
+
+ if (ni) {
+ LIST_REMOVE(ni, next);
+ _pthread_mutex_unlock(&sem_llock);
+ munmap(sem, sizeof(*sem));
+ free(ni);
+ return (0);
+ }
+ _pthread_mutex_unlock(&sem_llock);
+ return (-1);
+}
+
+int
+_libc_sem_unlink(const char *name)
+{
+ char path[PATH_MAX];
+
+ if (name[0] != '/') {
+ errno = ENOENT;
+ return -1;
+ }
+ name++;
+
+ strcpy(path, SEM_PREFIX);
+ if (strlcat(path, name, sizeof(path)) >= sizeof(path)) {
+ errno = ENAMETOOLONG;
+ return (-1);
+ }
+ return unlink(path);
+}
+
+int
+_libc_sem_destroy(sem_t *sem)
+{
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ if (sem->_kern._flags & SEM_NAMED) {
+ errno = EINVAL;
+ return (-1);
+ }
+ sem->_magic = 0;
+ return (0);
+}
+
+int
+_libc_sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
+{
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ *sval = (int)sem->_kern._count;
+ return (0);
+}
+
+static int
+usem_wake(struct _usem *sem)
+{
+ if (!sem->_has_waiters)
+ return (0);
+ return _umtx_op(sem, UMTX_OP_SEM_WAKE, 0, NULL, NULL);
+}
+
+static int
+usem_wait(struct _usem *sem, const struct timespec *timeout)
+{
+ if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
+ timeout->tv_nsec <= 0))) {
+ errno = ETIMEDOUT;
+ return (-1);
+ }
+ return _umtx_op(sem, UMTX_OP_SEM_WAIT, 0, NULL,
+ __DECONST(void*, timeout));
+}
+
+int
+_libc_sem_trywait(sem_t *sem)
+{
+ int val;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ while ((val = sem->_kern._count) > 0) {
+ if (atomic_cmpset_acq_int(&sem->_kern._count, val, val - 1))
+ return (0);
+ }
+ errno = EAGAIN;
+ return (-1);
+}
+
+static void
+sem_cancel_handler(void *arg)
+{
+ sem_t *sem = arg;
+
+ if (sem->_kern._has_waiters && sem->_kern._count)
+ usem_wake(&sem->_kern);
+}
+
+#define TIMESPEC_SUB(dst, src, val) \
+ do { \
+ (dst)->tv_sec = (src)->tv_sec - (val)->tv_sec; \
+ (dst)->tv_nsec = (src)->tv_nsec - (val)->tv_nsec; \
+ if ((dst)->tv_nsec < 0) { \
+ (dst)->tv_sec--; \
+ (dst)->tv_nsec += 1000000000; \
+ } \
+ } while (0)
+
+
+static int
+enable_async_cancel(void)
+{
+ int old;
+
+ _pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &old);
+ return (old);
+}
+
+static void
+restore_async_cancel(int val)
+{
+ _pthread_setcanceltype(val, NULL);
+}
+
+int
+_libc_sem_timedwait(sem_t * __restrict sem,
+ const struct timespec * __restrict abstime)
+{
+ struct timespec ts, ts2;
+ int val, retval, saved_cancel;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ retval = 0;
+ _pthread_testcancel();
+ for (;;) {
+ while ((val = sem->_kern._count) > 0) {
+ if (atomic_cmpset_acq_int(&sem->_kern._count, val, val - 1))
+ return (0);
+ }
+
+ if (retval)
+ break;
+
+ /*
+ * The timeout argument is only supposed to
+ * be checked if the thread would have blocked.
+ */
+ if (abstime != NULL) {
+ if (abstime->tv_nsec >= 1000000000 || abstime->tv_nsec < 0) {
+ errno = EINVAL;
+ return (-1);
+ }
+ clock_gettime(CLOCK_REALTIME, &ts);
+ TIMESPEC_SUB(&ts2, abstime, &ts);
+ }
+ pthread_cleanup_push(sem_cancel_handler, sem);
+ saved_cancel = enable_async_cancel();
+ retval = usem_wait(&sem->_kern, abstime ? &ts2 : NULL);
+ restore_async_cancel(saved_cancel);
+ pthread_cleanup_pop(0);
+ }
+ return (retval);
+}
+
+int
+_libc_sem_wait(sem_t *sem)
+{
+ return _libc_sem_timedwait(sem, NULL);
+}
+
+/*
+ * POSIX:
+ * The sem_post() interface is reentrant with respect to signals and may be
+ * invoked from a signal-catching function.
+ * The implementation does not use lock, so it should be safe.
+ */
+int
+_libc_sem_post(sem_t *sem)
+{
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ atomic_add_rel_int(&sem->_kern._count, 1);
+ if (sem->_kern._has_waiters)
+ return usem_wake(&sem->_kern);
+ return (0);
+}
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