Reviewed by: julian

Submitted by:	 john birrel

One version of the pthreads library
another will follow with differnt actions under some cases..
not QUITE complete

1 files changed, 360 insertions, 0 deletions

diff --git a/lib/libpthread/thread/thr_mutex.c b/lib/libpthread/thread/thr_mutex.c
new file mode 100644
index 0000000..0fc9fbb
--- /dev/null
+++ b/lib/libpthread/thread/thr_mutex.c
@@ -0,0 +1,360 @@
+/*
+ * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
+ * 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, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by John Birrell.
+ * 4. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL 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 REGENTS 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 <stdlib.h>
+#include <errno.h>
+#ifdef _THREAD_SAFE
+#include <pthread.h>
+#include "pthread_private.h"
+
+int
+pthread_mutex_init(pthread_mutex_t * mutex,
+		   const pthread_mutexattr_t * mutex_attr)
+{
+	enum pthread_mutextype type;
+	int             ret = 0;
+	int             status;
+
+	/* Check if the mutex attributes specify some mutex other than fast: */
+	if (mutex_attr != NULL && mutex_attr->m_type != MUTEX_TYPE_FAST) {
+		/* Check if the mutex type is out of range: */
+		if (mutex_attr->m_type >= MUTEX_TYPE_MAX) {
+			/* Return an invalid argument error: */
+			_thread_seterrno(_thread_run, EINVAL);
+			ret = -1;
+		} else {
+			/* Use the requested mutex type: */
+			type = mutex_attr->m_type;
+		}
+	} else {
+		/* Default to a fast mutex: */
+		type = MUTEX_TYPE_FAST;
+	}
+
+	/* Check no errors so far: */
+	if (ret == 0) {
+		/* Reset the mutex flags: */
+		mutex->m_flags = 0;
+
+		/* Block signals: */
+		_thread_kern_sig_block(&status);
+
+		/* Process according to mutex type: */
+		switch (type) {
+			/* Fast mutex: */
+		case MUTEX_TYPE_FAST:
+			/* Nothing to do here. */
+			break;
+
+			/* Counting mutex: */
+		case MUTEX_TYPE_COUNTING_FAST:
+			/* Reset the mutex count: */
+			mutex->m_data.m_count = 0;
+			break;
+
+			/* Trap invalid mutex types: */
+		default:
+			/* Return an invalid argument error: */
+			_thread_seterrno(_thread_run, EINVAL);
+			ret = -1;
+			break;
+		}
+
+		/* Initialise the rest of the mutex: */
+		_thread_queue_init(&mutex->m_queue);
+		mutex->m_flags |= MUTEX_FLAGS_INITED;
+		mutex->m_owner = NULL;
+		mutex->m_type = type;
+
+		/* Unblock signals: */
+		_thread_kern_sig_unblock(status);
+	}
+	/* Return the completion status: */
+	return (ret);
+}
+
+int
+pthread_mutex_destroy(pthread_mutex_t * mutex)
+{
+	int             ret = 0;
+	int             status;
+
+	/* Block signals: */
+	_thread_kern_sig_block(&status);
+
+	/* Process according to mutex type: */
+	switch (mutex->m_type) {
+		/* Fast mutex: */
+	case MUTEX_TYPE_FAST:
+		/* Nothing to do here. */
+		break;
+
+		/* Counting mutex: */
+	case MUTEX_TYPE_COUNTING_FAST:
+		/* Reset the mutex count: */
+		mutex->m_data.m_count = 0;
+		break;
+
+		/* Trap undefined mutex types: */
+	default:
+		/* Return an invalid argument error: */
+		_thread_seterrno(_thread_run, EINVAL);
+		ret = -1;
+		break;
+	}
+
+	/* Clean up the mutex in case that others want to use it: */
+	_thread_queue_init(&mutex->m_queue);
+	mutex->m_owner = NULL;
+	mutex->m_flags = 0;
+
+	/* Unblock signals: */
+	_thread_kern_sig_unblock(status);
+
+	/* Return the completion status: */
+	return (ret);
+}
+
+int
+pthread_mutex_trylock(pthread_mutex_t * mutex)
+{
+	int             ret = 0;
+	int             status;
+
+	/* Block signals: */
+	_thread_kern_sig_block(&status);
+
+	/* Process according to mutex type: */
+	switch (mutex->m_type) {
+		/* Fast mutex: */
+	case MUTEX_TYPE_FAST:
+		/* Check if this mutex is not locked: */
+		if (mutex->m_owner == NULL) {
+			/* Lock the mutex for the running thread: */
+			mutex->m_owner = _thread_run;
+		} else {
+			/* Return a busy error: */
+			_thread_seterrno(_thread_run, EBUSY);
+			ret = -1;
+		}
+		break;
+
+		/* Counting mutex: */
+	case MUTEX_TYPE_COUNTING_FAST:
+		/* Check if this mutex is locked: */
+		if (mutex->m_owner != NULL) {
+			/*
+			 * Check if the mutex is locked by the running
+			 * thread: 
+			 */
+			if (mutex->m_owner == _thread_run) {
+				/* Increment the lock count: */
+				mutex->m_data.m_count++;
+			} else {
+				/* Return a busy error: */
+				_thread_seterrno(_thread_run, EBUSY);
+				ret = -1;
+			}
+		} else {
+			/* Lock the mutex for the running thread: */
+			mutex->m_owner = _thread_run;
+		}
+		break;
+
+		/* Trap invalid mutex types: */
+	default:
+		/* Return an invalid argument error: */
+		_thread_seterrno(_thread_run, EINVAL);
+		ret = -1;
+		break;
+	}
+
+	/* Unblock signals: */
+	_thread_kern_sig_unblock(status);
+
+	/* Return the completion status: */
+	return (ret);
+}
+
+int
+pthread_mutex_lock(pthread_mutex_t * mutex)
+{
+	int             ret = 0;
+	int             status;
+
+	/* Block signals: */
+	_thread_kern_sig_block(&status);
+
+	/* Process according to mutex type: */
+	switch (mutex->m_type) {
+		/* Fast mutexes do not check for any error conditions: */
+	case MUTEX_TYPE_FAST:
+		/*
+		 * Enter a loop to wait for the mutex to be locked by the
+		 * current thread: 
+		 */
+		while (mutex->m_owner != _thread_run) {
+			/* Check if the mutex is not locked: */
+			if (mutex->m_owner == NULL) {
+				/* Lock the mutex for this thread: */
+				mutex->m_owner = _thread_run;
+			} else {
+				/*
+				 * Join the queue of threads waiting to lock
+				 * the mutex: 
+				 */
+				_thread_queue_enq(&mutex->m_queue, _thread_run);
+
+				/* Block signals: */
+				_thread_kern_sched_state(PS_MUTEX_WAIT, __FILE__, __LINE__);
+
+				/* Block signals: */
+				_thread_kern_sig_block(NULL);
+			}
+		}
+		break;
+
+		/* Counting mutex: */
+	case MUTEX_TYPE_COUNTING_FAST:
+		/*
+		 * Enter a loop to wait for the mutex to be locked by the
+		 * current thread: 
+		 */
+		while (mutex->m_owner != _thread_run) {
+			/* Check if the mutex is not locked: */
+			if (mutex->m_owner == NULL) {
+				/* Lock the mutex for this thread: */
+				mutex->m_owner = _thread_run;
+
+				/* Reset the lock count for this mutex: */
+				mutex->m_data.m_count = 0;
+			} else {
+				/*
+				 * Join the queue of threads waiting to lock
+				 * the mutex: 
+				 */
+				_thread_queue_enq(&mutex->m_queue, _thread_run);
+
+				/* Block signals: */
+				_thread_kern_sched_state(PS_MUTEX_WAIT, __FILE__, __LINE__);
+
+				/* Block signals: */
+				_thread_kern_sig_block(NULL);
+			}
+		}
+
+		/* Increment the lock count for this mutex: */
+		mutex->m_data.m_count++;
+		break;
+
+		/* Trap invalid mutex types: */
+	default:
+		/* Return an invalid argument error: */
+		_thread_seterrno(_thread_run, EINVAL);
+		ret = -1;
+		break;
+	}
+
+	/* Unblock signals: */
+	_thread_kern_sig_unblock(status);
+
+	/* Return the completion status: */
+	return (ret);
+}
+
+int
+pthread_mutex_unlock(pthread_mutex_t * mutex)
+{
+	int             ret = 0;
+	int             status;
+
+	/* Block signals: */
+	_thread_kern_sig_block(&status);
+
+	/* Process according to mutex type: */
+	switch (mutex->m_type) {
+		/* Fast mutexes do not check for any error conditions: */
+	case MUTEX_TYPE_FAST:
+		/* Check if the running thread is not the owner of the mutex: */
+		if (mutex->m_owner != _thread_run) {
+			/* Return an invalid argument error: */
+			_thread_seterrno(_thread_run, EINVAL);
+			ret = -1;
+		}
+		/*
+		 * Get the next thread from the queue of threads waiting on
+		 * the mutex: 
+		 */
+		else if ((mutex->m_owner = _thread_queue_deq(&mutex->m_queue)) != NULL) {
+			/* Allow the new owner of the mutex to run: */
+			mutex->m_owner->state = PS_RUNNING;
+		}
+		break;
+
+		/* Counting mutex: */
+	case MUTEX_TYPE_COUNTING_FAST:
+		/* Check if the running thread is not the owner of the mutex: */
+		if (mutex->m_owner != _thread_run) {
+			/* Return an invalid argument error: */
+			_thread_seterrno(_thread_run, EINVAL);
+			ret = -1;
+		}
+		/* Check if there are still counts: */
+		else if (mutex->m_data.m_count) {
+			/* Decrement the count: */
+			mutex->m_data.m_count--;
+		}
+		/*
+		 * Get the next thread from the queue of threads waiting on
+		 * the mutex: 
+		 */
+		else if ((mutex->m_owner = _thread_queue_deq(&mutex->m_queue)) != NULL) {
+			/* Allow the new owner of the mutex to run: */
+			mutex->m_owner->state = PS_RUNNING;
+		}
+		break;
+
+		/* Trap invalid mutex types: */
+	default:
+		/* Return an invalid argument error: */
+		_thread_seterrno(_thread_run, EINVAL);
+		ret = -1;
+		break;
+	}
+
+	/* Unblock signals: */
+	_thread_kern_sig_unblock(status);
+
+	/* Return the completion status: */
+	return (ret);
+}
+#endif