1 files changed, 450 insertions, 0 deletions
diff --git a/lib/libc/gen/sem_new.c b/lib/libc/gen/sem_new.c
new file mode 100644
index 0000000..c5dc7e7
--- /dev/null
+++ b/lib/libc/gen/sem_new.c
@@ -0,0 +1,450 @@
+/*
+ * 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"
+#include "libc_private.h"
+
+__weak_reference(_sem_close, sem_close);
+__weak_reference(_sem_destroy, sem_destroy);
+__weak_reference(_sem_getvalue, sem_getvalue);
+__weak_reference(_sem_init, sem_init);
+__weak_reference(_sem_open, sem_open);
+__weak_reference(_sem_post, sem_post);
+__weak_reference(_sem_timedwait, sem_timedwait);
+__weak_reference(_sem_trywait, sem_trywait);
+__weak_reference(_sem_unlink, sem_unlink);
+__weak_reference(_sem_wait, sem_wait);
+
+#define SEM_PREFIX	"/tmp/SEMD"
+#define SEM_MAGIC	((u_int32_t)0x73656d32)
+
+_Static_assert(SEM_VALUE_MAX <= USEM_MAX_COUNT, "SEM_VALUE_MAX too large");
+
+struct sem_nameinfo {
+	int open_count;
+	char *name;
+	dev_t dev;
+	ino_t ino;
+	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
+_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._flags = pshared ? USYNC_PROCESS_SHARED : 0;
+	return (0);
+}
+
+sem_t *
+_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, errsave;
+	int value = 0;
+
+	if (name[0] != '/') {
+		errno = EINVAL;
+		return (SEM_FAILED);
+	}
+	name++;
+	strcpy(path, SEM_PREFIX);
+	if (strlcat(path, name, sizeof(path)) >= sizeof(path)) {
+		errno = ENAMETOOLONG;
+		return (SEM_FAILED);
+	}
+	if (flags & ~(O_CREAT|O_EXCL)) {
+		errno = EINVAL;
+		return (SEM_FAILED);
+	}
+	if ((flags & O_CREAT) != 0) {
+		va_start(ap, flags);
+		mode = va_arg(ap, int);
+		value = va_arg(ap, int);
+		va_end(ap);
+	}
+	fd = -1;
+	_pthread_once(&once, sem_module_init);
+
+	_pthread_mutex_lock(&sem_llock);
+	LIST_FOREACH(ni, &sem_list, next) {
+		if (ni->name != NULL && strcmp(name, ni->name) == 0) {
+			fd = _open(path, flags | O_RDWR | O_CLOEXEC |
+			    O_EXLOCK, mode);
+			if (fd == -1 || _fstat(fd, &sb) == -1)
+				goto error;
+			if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT |
+			    O_EXCL) || ni->dev != sb.st_dev ||
+			    ni->ino != sb.st_ino) {
+				ni->name = NULL;
+				ni = NULL;
+				break;
+			}
+			ni->open_count++;
+			sem = ni->sem;
+			_pthread_mutex_unlock(&sem_llock);
+			_close(fd);
+			return (sem);
+		}
+	}
+
+	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);
+
+	if (fd == -1) {
+		fd = _open(path, flags | O_RDWR | O_CLOEXEC | O_EXLOCK, mode);
+		if (fd == -1 || _fstat(fd, &sb) == -1)
+			goto error;
+	}
+	if (sb.st_size < sizeof(sem_t)) {
+		sem_t tmp;
+
+		tmp._magic = SEM_MAGIC;
+		tmp._kern._count = value;
+		tmp._kern._flags = USYNC_PROCESS_SHARED | SEM_NAMED;
+		if (_write(fd, &tmp, sizeof(tmp)) != sizeof(tmp))
+			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;
+	ni->dev = sb.st_dev;
+	ni->ino = sb.st_ino;
+	LIST_INSERT_HEAD(&sem_list, ni, next);
+	_close(fd);
+	_pthread_mutex_unlock(&sem_llock);
+	return (sem);
+
+error:
+	errsave = errno;
+	if (fd != -1)
+		_close(fd);
+	if (sem != NULL)
+		munmap(sem, sizeof(sem_t));
+	free(ni);
+	_pthread_mutex_unlock(&sem_llock);
+	errno = errsave;
+	return (SEM_FAILED);
+}
+
+int
+_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_once(&once, sem_module_init);
+
+	_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);
+	errno = EINVAL;
+	return (-1);
+}
+
+int
+_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
+_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
+_sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
+{
+
+	if (sem_check_validity(sem) != 0)
+		return (-1);
+
+	*sval = (int)USEM_COUNT(sem->_kern._count);
+	return (0);
+}
+
+static __inline int
+usem_wake(struct _usem2 *sem)
+{
+	return _umtx_op(sem, UMTX_OP_SEM2_WAKE, 0, NULL, NULL);
+}
+
+static __inline int
+usem_wait(struct _usem2 *sem, const struct timespec *abstime)
+{
+	struct _umtx_time *tm_p, timeout;
+	size_t tm_size;
+
+	if (abstime == NULL) {
+		tm_p = NULL;
+		tm_size = 0;
+	} else {
+		timeout._clockid = CLOCK_REALTIME;
+		timeout._flags = UMTX_ABSTIME;
+		timeout._timeout = *abstime;
+		tm_p = &timeout;
+		tm_size = sizeof(timeout);
+	}
+	return _umtx_op(sem, UMTX_OP_SEM2_WAIT, 0, 
+		    (void *)tm_size, __DECONST(void*, tm_p));
+}
+
+int
+_sem_trywait(sem_t *sem)
+{
+	int val;
+
+	if (sem_check_validity(sem) != 0)
+		return (-1);
+
+	while (USEM_COUNT(val = sem->_kern._count) > 0) {
+		if (atomic_cmpset_acq_int(&sem->_kern._count, val, val - 1))
+			return (0);
+	}
+	errno = EAGAIN;
+	return (-1);
+}
+
+int
+_sem_timedwait(sem_t * __restrict sem,
+	const struct timespec * __restrict abstime)
+{
+	int val, retval;
+
+	if (sem_check_validity(sem) != 0)
+		return (-1);
+
+	retval = 0;
+	_pthread_testcancel();
+	for (;;) {
+		while (USEM_COUNT(val = sem->_kern._count) > 0) {
+			if (atomic_cmpset_acq_int(&sem->_kern._count, val, val - 1))
+				return (0);
+		}
+
+		if (retval) {
+			_pthread_testcancel();
+			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);
+			}
+		}
+		_pthread_cancel_enter(1);
+		retval = usem_wait(&sem->_kern, abstime);
+		_pthread_cancel_leave(0);
+	}
+	return (retval);
+}
+
+int
+_sem_wait(sem_t *sem)
+{
+	return _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
+_sem_post(sem_t *sem)
+{
+	unsigned int count;
+
+	if (sem_check_validity(sem) != 0)
+		return (-1);
+
+	do {
+		count = sem->_kern._count;
+		if (USEM_COUNT(count) + 1 > SEM_VALUE_MAX) {
+			errno = EOVERFLOW;
+			return (-1);
+		}
+	} while (!atomic_cmpset_rel_int(&sem->_kern._count, count, count + 1));
+	if (count & USEM_HAS_WAITERS)
+		usem_wake(&sem->_kern);
+	return (0);
+}