diff --git a/Makefile.dep b/Makefile.dep
index 39bd45a516031f45a7045271b60e32e7041996bc..60614da7582ce1003c7bbe2bd09dd0dc1231ae0e 100644
--- a/Makefile.dep
+++ b/Makefile.dep
@@ -301,6 +301,11 @@ ifneq (,$(filter posix,$(USEMODULE)))
USEMODULE += vtimer
endif
+ifneq (,$(filter posix_semaphore,$(USEMODULE)))
+ USEMODULE += sem
+ USEMODULE += vtimer
+endif
+
ifneq (,$(filter sem,$(USEMODULE)))
USEMODULE += vtimer
endif
diff --git a/sys/Makefile b/sys/Makefile
index 78f375543289937500880f0dc7e2cb4d09747eae..8baba47737237ea1ede70f76fd767b467d10b92b 100644
--- a/sys/Makefile
+++ b/sys/Makefile
@@ -1,3 +1,6 @@
+ifneq (,$(filter posix_semaphore,$(USEMODULE)))
+ DIRS += posix/semaphore
+endif
ifneq (,$(filter posix_sockets,$(USEMODULE)))
DIRS += posix/sockets
endif
diff --git a/sys/Makefile.include b/sys/Makefile.include
index 1c4d405dee44b8b031c431af1b8dc73be549b5b7..eb3523ce0e3a36dea6d5032334467094749651c0 100644
--- a/sys/Makefile.include
+++ b/sys/Makefile.include
@@ -18,6 +18,9 @@ ifneq (,$(filter posix,$(USEMODULE)))
USEMODULE_INCLUDES += $(RIOTBASE)/sys/posix/include
USEMODULE_INCLUDES += $(RIOTBASE)/sys/net/include
endif
+ifneq (,$(filter posix_semaphore,$(USEMODULE)))
+ USEMODULE_INCLUDES += $(RIOTBASE)/sys/posix/include
+endif
ifneq (,$(filter posix_sockets,$(USEMODULE)))
USEMODULE_INCLUDES += $(RIOTBASE)/sys/posix/include
endif
diff --git a/sys/posix/include/semaphore.h b/sys/posix/include/semaphore.h
index 0c21e0fb42b20ee4d6b81150c4e3bfeb8b59850d..cbf3fd64f9e4979293a8ff44eec95104d9a6f6fb 100644
--- a/sys/posix/include/semaphore.h
+++ b/sys/posix/include/semaphore.h
@@ -6,117 +6,170 @@
* directory for more details.
*/
-#ifndef _SEMAPHORE_H
-#define _SEMAPHORE_H 1
+/**
+ * @defgroup posix_semaphore POSIX semaphores
+ * @ingroup posix
+ * @{
+ * @file
+ * @brief Semaphores
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/semaphore.h.html">
+ * The Open Group Base Specifications Issue 7, <semaphore.h>
+ * </a>
+ * @author Christian Mehlis <mehlis@inf.fu-berlin.de>
+ * @author Martine Lenders <mlenders@inf.fu-berlin.de>
+ * @author René Kijewski <kijewski@inf.fu-berlin.de>
+ */
+#ifndef POSIX_SEMAPHORE_H_
+#define POSIX_SEMAPHORE_H_
+
+#include <errno.h>
#include <time.h>
-#include "priority_queue.h"
+#include "sem.h"
#ifdef __cplusplus
extern "C" {
#endif
-/** Value returned if `sem_open' failed. */
-#define SEM_FAILED ((sem_t *) 0)
-
/**
- * @brief Semaphore struct
+ * @brief Value returned if `sem_open' failed.
*/
-typedef struct sem {
- /** the value of the semaphore */
- volatile unsigned int value;
- /** list of threads waiting for the semaphore */
- priority_queue_t queue;
-} sem_t;
+#define SEM_FAILED ((sem_t *) 0)
/**
- * @brief Initialize semaphore object SEM to VALUE.
+ * @brief Initialize semaphore.
*
- * @param sem Semaphore to initialize
- * @param pshared unused
- * @param value Value to set
- */
-int sem_init(sem_t *sem, int pshared, unsigned int value);
-
-/**
- * @brief Free resources associated with semaphore object SEM.
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_init.html">
+ * The Open Group Base Specifications Issue 7, sem_init()
+ * </a>
*
- * @param sem Semaphore to destroy
- */
-int sem_destroy(sem_t *sem);
-
-/*
- * @brief Open a named semaphore NAME with open flags OFLAG.
+ * The sem_init() function shall initialize the unnamed semaphore referred to by @p sem. The value
+ * of the initialized semaphore shall be @p value. Following a successful call to sem_init(),
+ * the semaphore may be used in subsequent calls to sem_wait(), sem_timedwait(),
+ * sem_trywait(), sem_post(), and sem_destroy(). This semaphore shall remain usable until the
+ * semaphore is destroyed.
*
- * @brief WARNING: named semaphore are currently not supported
+ * @param[out] sem Semaphore to initialize.
+ * @param[in] pshared **(unused, since RIOT only has threads)**
+ * Semaphore is shared between processes not threads.
+ * @param[in] value Value to set.
*
- * @param name Name to set
- * @param oflag Flags to set
+ * @return 0 on success.
+ * @return -EINVAL, if semaphore is invalid.
*/
-sem_t *sem_open(const char *name, int oflag, ...);
+#define sem_init(sem, pshared, value) sem_create(sem, value)
/**
- * @brief Close descriptor for named semaphore SEM.
+ * @brief Open a named semaphore @p name with open flags @p oflag.
*
- * @brief WARNING: named semaphore are currently not supported
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_open.html">
+ * The Open Group Base Specifications Issue 7, sem_open()
+ * </a>
*
- * @param sem Semaphore to close
- */
-int sem_close(sem_t *sem);
-
-/**
- * @brief Remove named semaphore NAME.
+ * @todo named semaphore are currently not supported
*
- * @brief WARNING: named semaphore are currently not supported
+ * @param[in] name Name to set.
+ * @param[in] oflag Flags to set.
*
- * @param name Name to unlink
+ * @return Always @ref SEM_FAILED, since it is not implemented currently.
*/
-int sem_unlink(const char *name);
+#define sem_open(name, oflag, ...) (SEM_FAILED)
/**
- * @brief Wait for SEM being posted.
+ * @brief Close descriptor for named semaphore @p sem.
*
- * @param sem Semaphore to wait
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_close.html">
+ * The Open Group Base Specifications Issue 7, sem_close()
+ * </a>
+ *
+ * @todo named semaphore are currently not supported
+ *
+ * @param[in] sem Semaphore to close.
+ *
+ * @return Always -1, since it is not implemented currently.
*/
-int sem_wait(sem_t *sem);
+#define sem_close(sem) (-1)
/**
- * @brief Similar to `sem_wait' but wait only until ABSTIME.
+ * @brief Remove named semaphore @p name.
+ *
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_unlink.html">
+ * The Open Group Base Specifications Issue 7, sem_unlink()
+ * </a>
*
- * @brief WARNING: currently not supported
+ * @todo named semaphore are currently not supported
*
- * @param sem Semaphore to wait on
- * @param abstime Max time to wait for a post
+ * @param[in] name Name to unlink.
*
+ * @return Always -1, since it is not implemented currently.
+ */
+#define sem_unlink(name) (-1)
+
+/**
+ * @brief Similar to `sem_wait' but wait only until @p abstime.
+ *
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_timedwait.html">
+ * The Open Group Base Specifications Issue 7, sem_timedwait()
+ * </a>
+ *
+ * The sem_timedwait() function shall lock the semaphore referenced by @p sem as in the sem_wait()
+ * function. However, if the semaphore cannot be locked without waiting for another process or
+ * thread to unlock the semaphore by performing a sem_post() function, this wait shall be
+ * terminated when the specified timeout expires.
+ *
+ * @param[in] sem Semaphore to wait on.
+ * @param[in] abstime Absolute time (that is when the clock on which temouts are based equals
+ * this value) the timeout for the wait shall expire. If the value specified
+ * has already passed the timeout expires immediately.
+ *
+ * @return 0 on success
+ * @return -EINVAL, if semaphore is invalid.
+ * @return -ETIMEDOUT, if the semaphore times out.
+ * @return -ECANCELED, if the semaphore was destroyed.
*/
int sem_timedwait(sem_t *sem, const struct timespec *abstime);
/**
* @brief Test whether SEM is posted.
*
- * @param sem Semaphore to trywait on
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_trywait.html">
+ * The Open Group Base Specifications Issue 7, sem_trywait()
+ * </a>
*
- */
-int sem_trywait(sem_t *sem);
-
-/**
- * @brief Post SEM.
+ * @param[in] sem Semaphore to try to wait on
*
- * @param sem Semaphore to post on
+ * @return 0 on success
+ * @return -EINVAL, if semaphore is invalid.
+ * @return -EAGAIN, if the semaphore was already locked.
*/
-int sem_post(sem_t *sem);
+int sem_trywait(sem_t *sem);
/**
* @brief Get current value of SEM and store it in *SVAL.
*
- * @param sem Semaphore to get value from
- * @param sval place whre value goes to
+ * @see <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_getvalue.html">
+ * The Open Group Base Specifications Issue 7, sem_getvalue()
+ * </a>
+ *
+ * @param[in] sem Semaphore to get the value from.
+ * @param[out] sval Place where value goes to.
+ *
+ * @return 0 on success
+ * @return -EINVAL, if semaphore is invalid.
*/
-int sem_getvalue(sem_t *sem, int *sval);
+static inline int sem_getvalue(sem_t *sem, int *sval)
+{
+ if (sem != NULL) {
+ *sval = (int)sem->value;
+ return 0;
+ }
+ return -EINVAL;
+}
#ifdef __cplusplus
}
#endif
-#endif /* semaphore.h */
+#endif /* POSIX_SEMAPHORE_H_ */
+/** @} */
diff --git a/sys/posix/semaphore.c b/sys/posix/semaphore.c
deleted file mode 100644
index 09a4c40c346586ea16a6218bed0b691d0d631e9c..0000000000000000000000000000000000000000
--- a/sys/posix/semaphore.c
+++ /dev/null
@@ -1,159 +0,0 @@
-/**
- * Semaphore implemenation
- *
- * Copyright (C) 2013 Freie Universität Berlin
- *
- * This file is subject to the terms and conditions of the GNU Lesser
- * General Public License v2.1. See the file LICENSE in the top level
- * directory for more details.
- *
- * @ingroup posix
- *
- * @{
- *
- * @file
- * @brief Implementation of semaphores with priority queues
- *
- * @author Christian Mehlis <mehlis@inf.fu-berlin.de>
- * @author René Kijewski <kijewski@inf.fu-berlin.de>
- *
- * @}
- */
-
-#include <inttypes.h>
-
-#include "irq.h"
-#include "sched.h"
-#include "tcb.h"
-#include "thread.h"
-
-#define ENABLE_DEBUG (0)
-#include "debug.h"
-
-#include "semaphore.h"
-
-int sem_init(sem_t *sem, int pshared, unsigned int value)
-{
- (void) pshared; /* nothing to do */
-
- sem->value = value;
-
- /* waiters for the mutex */
- sem->queue.first = NULL;
-
- return 0;
-}
-
-int sem_destroy(sem_t *sem)
-{
- if (sem->queue.first) {
- DEBUG("sem_destroy: %" PRIkernel_pid ": tried to destroy active semaphore.\n",
- sched_active_thread->pid);
- return -1;
- }
- return 0;
-}
-
-sem_t *sem_open(const char *name, int oflag, ...)
-{
- (void) name; /* named semaphore currently not supported */
- (void) oflag;
- return SEM_FAILED;
-}
-
-int sem_close(sem_t *sem)
-{
- (void) sem; /* named semaphore currently not supported */
- return -1;
-}
-
-int sem_unlink(const char *name)
-{
- (void) name; /* named semaphore currently not supported */
- return -1;
-}
-
-int sem_wait(sem_t *sem)
-{
- while (1) {
- unsigned old_state = disableIRQ();
-
- unsigned value = sem->value;
- if (value != 0) {
- sem->value = value - 1;
- restoreIRQ(old_state);
- return 1;
- }
-
- /* I'm going blocked */
- priority_queue_node_t n;
- n.priority = (uint32_t) sched_active_thread->priority;
- n.data = (uintptr_t) sched_active_thread;
- n.next = NULL;
- priority_queue_add(&sem->queue, &n);
-
- DEBUG("sem_wait: %" PRIkernel_pid ": Adding node to mutex queue: prio: %" PRIu32 "\n",
- sched_active_thread->pid, sched_active_thread->priority);
-
- /* scheduler should schedule an other thread, that unlocks the
- * mutex in the future, when this happens I get scheduled again
- */
- sched_set_status((tcb_t*) sched_active_thread, STATUS_MUTEX_BLOCKED);
- restoreIRQ(old_state);
- thread_yield_higher();
- }
-}
-
-int sem_timedwait(sem_t *sem, const struct timespec *abstime)
-{
- (void) sem; /* timedwait currently not supported */
- (void) abstime;
- return -1; /* signal problem */
-}
-
-int sem_trywait(sem_t *sem)
-{
- unsigned old_state = disableIRQ();
- int result;
-
- unsigned value = sem->value;
- if (value == 0) {
- result = -1;
- }
- else {
- result = 0;
- sem->value = value - 1;
- }
-
- restoreIRQ(old_state);
- return result;
-}
-
-int sem_post(sem_t *sem)
-{
- unsigned old_state = disableIRQ();
- ++sem->value;
-
- priority_queue_node_t *next = priority_queue_remove_head(&sem->queue);
- if (next) {
- tcb_t *next_process = (tcb_t*) next->data;
- DEBUG("sem_post: %" PRIkernel_pid ": waking up %" PRIkernel_pid "\n",
- sched_active_thread->pid, next_process->pid);
- sched_set_status(next_process, STATUS_PENDING);
-
- uint16_t prio = next_process->priority;
- restoreIRQ(old_state);
- sched_switch(prio);
- }
- else {
- restoreIRQ(old_state);
- }
-
- return 1;
-}
-
-int sem_getvalue(sem_t *sem, int *sval)
-{
- *sval = sem->value;
- return 0;
-}
diff --git a/sys/posix/semaphore/Makefile b/sys/posix/semaphore/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..68d9a081b01f2d1923cfb9a18ebbfc41c8df6a28
--- /dev/null
+++ b/sys/posix/semaphore/Makefile
@@ -0,0 +1,3 @@
+MODULE = posix_semaphore
+
+include $(RIOTBASE)/Makefile.base
diff --git a/sys/posix/semaphore/posix_semaphore.c b/sys/posix/semaphore/posix_semaphore.c
new file mode 100644
index 0000000000000000000000000000000000000000..4f9756296fdc5494ceed9990937e42e9ee5e8726
--- /dev/null
+++ b/sys/posix/semaphore/posix_semaphore.c
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2013 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @{
+ *
+ * @file
+ *
+ * @author Christian Mehlis <mehlis@inf.fu-berlin.de>
+ * @author Martine Lenders <mlenders@inf.fu-berlin.de>
+ * @author René Kijewski <kijewski@inf.fu-berlin.de>
+ */
+
+#include <errno.h>
+#include <inttypes.h>
+
+#include "irq.h"
+#include "sched.h"
+#include "sem.h"
+#include "tcb.h"
+#include "timex.h"
+#include "thread.h"
+#include "vtimer.h"
+
+#define ENABLE_DEBUG (0)
+#include "debug.h"
+
+#include "semaphore.h"
+
+#define USEC_IN_NS (1000)
+
+int sem_timedwait(sem_t *sem, const struct timespec *abstime)
+{
+ timex_t now, timeout = { abstime->tv_sec, abstime->tv_nsec / USEC_IN_NS };
+ int res;
+ vtimer_now(&now);
+ if (timex_cmp(now, timeout) > 0) {
+ errno = ETIMEDOUT;
+ return -ETIMEDOUT;
+ }
+ timeout = timex_sub(timeout, now);
+ res = sem_wait_timed(sem, &timeout);
+ if (res < 0) {
+ errno = -res;
+ }
+ return res;
+}
+
+int sem_trywait(sem_t *sem)
+{
+ unsigned int old_state, value;
+ int result;
+ if (sem == NULL) {
+ errno = EINVAL;
+ return -EINVAL;
+ }
+ old_state = disableIRQ();
+ value = sem->value;
+ if (value == 0) {
+ errno = EAGAIN;
+ result = -EAGAIN;
+ }
+ else {
+ result = 0;
+ sem->value = value - 1;
+ }
+
+ restoreIRQ(old_state);
+ return result;
+}
+
+/** @} */
diff --git a/tests/posix_semaphore/Makefile b/tests/posix_semaphore/Makefile
index edb55ba23da3947e13f8155b4f94ad3ea9afd86d..619d444f8ec78fc3f462a83401ee5c9eebfde232 100644
--- a/tests/posix_semaphore/Makefile
+++ b/tests/posix_semaphore/Makefile
@@ -4,7 +4,7 @@ include ../Makefile.tests_common
BOARD_INSUFFICIENT_MEMORY := msb-430 msb-430h mbed_lpc1768 chronos stm32f0discovery \
pca10000 pca10005 weio yunjia-nrf51822 nrf6310 spark-core
-USEMODULE += posix
+USEMODULE += posix_semaphore
DISABLE_MODULE += auto_init
diff --git a/tests/posix_semaphore/main.c b/tests/posix_semaphore/main.c
index c6258511a38585e987063515d8efa9bc93e6324f..55dc06f81b8b15465ba811964bbfde1d34d156e6 100644
--- a/tests/posix_semaphore/main.c
+++ b/tests/posix_semaphore/main.c
@@ -1,6 +1,7 @@
/*
* Copyright (C) 2013 Christian Mehlis <mehlis@inf.fu-berlin.de>
* Copyright (C) 2013 René Kijewski <rene.kijewski@fu-berlin.de>
+ * Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level