Added a wrapper class around POSIX semaphores.
authorTobias Brunner <tobias@strongswan.org>
Wed, 21 Dec 2011 17:22:23 +0000 (18:22 +0100)
committerTobias Brunner <tobias@strongswan.org>
Wed, 2 May 2012 12:45:37 +0000 (14:45 +0200)
src/libstrongswan/Android.mk
src/libstrongswan/Makefile.am
src/libstrongswan/threading/semaphore.c [new file with mode: 0644]
src/libstrongswan/threading/semaphore.h [new file with mode: 0644]

index d33bee6..24d9978 100644 (file)
@@ -62,6 +62,7 @@ selectors/traffic_selector.c selectors/traffic_selector.h \
 threading/thread.h threading/thread.c \
 threading/thread_value.h threading/thread_value.c \
 threading/mutex.h threading/mutex.c threading/condvar.h  \
+threading/semaphore.h threading/semaphore.c \
 threading/rwlock.h threading/rwlock.c \
 threading/lock_profiler.h \
 utils.h utils.c \
index 7bb0812..8f3b092 100644 (file)
@@ -60,6 +60,7 @@ selectors/traffic_selector.c selectors/traffic_selector.h \
 threading/thread.h threading/thread.c \
 threading/thread_value.h threading/thread_value.c \
 threading/mutex.h threading/mutex.c threading/condvar.h  \
+threading/semaphore.h threading/semaphore.c \
 threading/rwlock.h threading/rwlock.c \
 threading/lock_profiler.h \
 utils.h utils.c \
diff --git a/src/libstrongswan/threading/semaphore.c b/src/libstrongswan/threading/semaphore.c
new file mode 100644 (file)
index 0000000..b7ab9ce
--- /dev/null
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2011 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include <semaphore.h>
+
+#include <library.h>
+
+#include "semaphore.h"
+
+typedef struct private_semaphore_t private_semaphore_t;
+
+/**
+ * private data of a semaphore
+ */
+struct private_semaphore_t {
+       /**
+        * public interface
+        */
+       semaphore_t public;
+
+       /**
+        * wrapped POSIX semaphore object
+        */
+       sem_t sem;
+};
+
+METHOD(semaphore_t, wait_, void,
+       private_semaphore_t *this)
+{
+       sem_wait(&this->sem);
+}
+
+METHOD(semaphore_t, timed_wait_abs, bool,
+       private_semaphore_t *this, timeval_t tv)
+{
+       timespec_t ts;
+
+       ts.tv_sec = tv.tv_sec;
+       ts.tv_nsec = tv.tv_usec * 1000;
+
+       /* there are errors other than ETIMEDOUT possible, but we consider them
+        * all as timeout */
+       return sem_timedwait(&this->sem, &ts) == -1;
+}
+
+METHOD(semaphore_t, timed_wait, bool,
+       private_semaphore_t *this, u_int timeout)
+{
+       timeval_t tv, add;
+
+       add.tv_sec = timeout / 1000;
+       add.tv_usec = (timeout % 1000) * 1000;
+
+       time_monotonic(&tv);
+       timeradd(&tv, &add, &tv);
+
+       return timed_wait_abs(this, tv);
+}
+
+METHOD(semaphore_t, post, void,
+       private_semaphore_t *this)
+{
+       sem_post(&this->sem);
+}
+
+METHOD(semaphore_t, destroy, void,
+       private_semaphore_t *this)
+{
+       sem_destroy(&this->sem);
+       free(this);
+}
+
+/*
+ * Described in header
+ */
+semaphore_t *semaphore_create(u_int value)
+{
+       private_semaphore_t *this;
+
+       INIT(this,
+               .public = {
+                       .wait = _wait_,
+                       .timed_wait = _timed_wait,
+                       .timed_wait_abs = _timed_wait_abs,
+                       .post = _post,
+                       .destroy = _destroy,
+               },
+       );
+
+       sem_init(&this->sem, 0, value);
+
+       return &this->public;
+}
+
diff --git a/src/libstrongswan/threading/semaphore.h b/src/libstrongswan/threading/semaphore.h
new file mode 100644 (file)
index 0000000..cdb0a6f
--- /dev/null
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2011 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup semaphore semaphore
+ * @{ @ingroup threading
+ */
+
+#ifndef THREADING_SEMAPHORE_H_
+#define THREADING_SEMAPHORE_H_
+
+typedef struct semaphore_t semaphore_t;
+
+/**
+ * A semaphore is basically an integer whose value is never allowed to be
+ * lower than 0.  Two operations can be performed on it: increment the
+ * value by one, and decrement the value by one.  If the value is currently
+ * zero, then the decrement operation will blcok until the value becomes
+ * greater than zero.
+ */
+struct semaphore_t {
+
+       /**
+        * Decrease the value by one, if it is greater than zero. Otherwise the
+        * current thread is blocked and it waits until the value increases.
+        */
+       void (*wait)(semaphore_t *this);
+
+       /**
+        * Decrease the value by one, if it is greater than zero. Otherwise the
+        * current thread is blocked and it waits until the value increases, or the
+        * call times out.
+        *
+        * @param timeout               timeout im ms
+        * @return                              TRUE if timed out, FALSE otherwise
+        */
+       bool (*timed_wait)(semaphore_t *this, u_int timeout);
+
+       /**
+        * Decrease the value by one, if it is greater than zero. Otherwise the
+        * current thread is blocked and it waits until the value increases, or the
+        * call times out.
+        *
+        * The passed timeval should be calculated based on the time_monotonic()
+        * function.
+        *
+        * @param tv                    absolute time until timeout
+        * @return                              TRUE if timed out, FALSE otherwise
+        */
+       bool (*timed_wait_abs)(semaphore_t *this, timeval_t tv);
+
+       /**
+        * Increase the value by one. If the value becomes greater than zero, then
+        * another thread waiting will be woken up.
+        */
+       void (*post)(semaphore_t *this);
+
+       /**
+        * Destroy a semaphore and free its resources.
+        */
+       void (*destroy)(semaphore_t *this);
+};
+
+/**
+ * Create a semaphore instance.
+ *
+ * @param value                initial value (typically 0)
+ * @return                     semaphore instance
+ */
+semaphore_t *semaphore_create(u_int value);
+
+#endif /** THREADING_SEMAPHORE_H_ @} */
+