diff options
Diffstat (limited to 'lib/libc_r/uthread/uthread_cond.c')
-rw-r--r-- | lib/libc_r/uthread/uthread_cond.c | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/lib/libc_r/uthread/uthread_cond.c b/lib/libc_r/uthread/uthread_cond.c new file mode 100644 index 0000000..930f31a --- /dev/null +++ b/lib/libc_r/uthread/uthread_cond.c @@ -0,0 +1,293 @@ +/* + * 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_cond_init(pthread_cond_t * cond, const pthread_condattr_t * cond_attr) +{ + enum pthread_cond_type type; + int rval = 0; + + /* + * Check if a pointer to a condition variable attribute structure was + * passed by the caller: + */ + if (cond_attr != NULL) { + /* Default to a fast condition variable: */ + type = cond_attr->c_type; + } else { + /* Default to a fast condition variable: */ + type = COND_TYPE_FAST; + } + + /* Process according to condition variable type: */ + switch (type) { + /* Fast condition variable: */ + case COND_TYPE_FAST: + /* Nothing to do here. */ + break; + + /* Trap invalid condition variable types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + rval = -1; + break; + } + + /* Check for no errors: */ + if (rval == 0) { + /* Initialise the condition variable structure: */ + _thread_queue_init(&cond->c_queue); + cond->c_flags |= COND_FLAGS_INITED; + cond->c_type = type; + } + /* Return the completion status: */ + return (rval); +} + +int +pthread_cond_destroy(pthread_cond_t * cond) +{ + int rval = 0; + + /* Process according to condition variable type: */ + switch (cond->c_type) { + /* Fast condition variable: */ + case COND_TYPE_FAST: + /* Nothing to do here. */ + break; + + /* Trap invalid condition variable types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + rval = -1; + break; + } + + /* Check for errors: */ + if (rval == 0) { + /* Destroy the contents of the condition structure: */ + _thread_queue_init(&cond->c_queue); + cond->c_flags = 0; + } + /* Return the completion status: */ + return (rval); +} + +int +pthread_cond_wait(pthread_cond_t * cond, pthread_mutex_t * mutex) +{ + int rval = 0; + int status; + + /* Block signals: */ + _thread_kern_sig_block(&status); + + /* Process according to condition variable type: */ + switch (cond->c_type) { + /* Fast condition variable: */ + case COND_TYPE_FAST: + /* Queue the running thread for the condition variable: */ + _thread_queue_enq(&cond->c_queue, _thread_run); + + /* Unlock the mutex: */ + pthread_mutex_unlock(mutex); + + /* Schedule the next thread: */ + _thread_kern_sched_state(PS_COND_WAIT, __FILE__, __LINE__); + + /* Block signals: */ + _thread_kern_sig_block(NULL); + + /* Lock the mutex: */ + rval = pthread_mutex_lock(mutex); + break; + + /* Trap invalid condition variable types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + rval = -1; + break; + } + + /* Unblock signals: */ + _thread_kern_sig_unblock(status); + + /* Return the completion status: */ + return (rval); +} + +int +pthread_cond_timedwait(pthread_cond_t * cond, pthread_mutex_t * mutex, + const struct timespec * abstime) +{ + int rval = 0; + int status; + + /* Block signals: */ + _thread_kern_sig_block(&status); + + /* Process according to condition variable type: */ + switch (cond->c_type) { + /* Fast condition variable: */ + case COND_TYPE_FAST: + /* Set the wakeup time: */ + _thread_run->wakeup_time.ts_sec = abstime->ts_sec; + _thread_run->wakeup_time.ts_nsec = abstime->ts_nsec; + + /* Reset the timeout flag: */ + _thread_run->timeout = 0; + + /* Queue the running thread for the condition variable: */ + _thread_queue_enq(&cond->c_queue, _thread_run); + + /* Unlock the mutex: */ + if ((rval = pthread_mutex_unlock(mutex)) != 0) { + /* + * Cannot unlock the mutex, so remove the running + * thread from the condition variable queue: + */ + _thread_queue_deq(&cond->c_queue); + } else { + /* Schedule the next thread: */ + _thread_kern_sched_state(PS_COND_WAIT, __FILE__, __LINE__); + + /* Block signals: */ + _thread_kern_sig_block(NULL); + + /* Lock the mutex: */ + if ((rval = pthread_mutex_lock(mutex)) != 0) { + } + /* Check if the wait timed out: */ + else if (_thread_run->timeout) { + /* Return a timeout error: */ + _thread_seterrno(_thread_run, EAGAIN); + rval = -1; + } + } + break; + + /* Trap invalid condition variable types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + rval = -1; + break; + } + + /* Unblock signals: */ + _thread_kern_sig_unblock(status); + + /* Return the completion status: */ + return (rval); +} + +int +pthread_cond_signal(pthread_cond_t * cond) +{ + int rval = 0; + int status; + pthread_t pthread; + + /* Block signals: */ + _thread_kern_sig_block(&status); + + /* Process according to condition variable type: */ + switch (cond->c_type) { + /* Fast condition variable: */ + case COND_TYPE_FAST: + /* Bring the next thread off the condition queue: */ + if ((pthread = _thread_queue_deq(&cond->c_queue)) != NULL) { + /* Allow the thread to run: */ + pthread->state = PS_RUNNING; + } + break; + + /* Trap invalid condition variable types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + rval = -1; + break; + } + + /* Unblock signals: */ + _thread_kern_sig_unblock(status); + + /* Return the completion status: */ + return (rval); +} + +int +pthread_cond_broadcast(pthread_cond_t * cond) +{ + int rval = 0; + int status; + pthread_t pthread; + + /* Block signals: */ + _thread_kern_sig_block(&status); + + /* Process according to condition variable type: */ + switch (cond->c_type) { + /* Fast condition variable: */ + case COND_TYPE_FAST: + /* Enter a loop to bring all threads off the condition queue: */ + while ((pthread = _thread_queue_deq(&cond->c_queue)) != NULL) { + /* Allow the thread to run: */ + pthread->state = PS_RUNNING; + } + break; + + /* Trap invalid condition variable types: */ + default: + /* Return an invalid argument error: */ + _thread_seterrno(_thread_run, EINVAL); + rval = -1; + break; + } + + /* Unblock signals: */ + _thread_kern_sig_unblock(status); + + /* Return the completion status: */ + return (rval); +} +#endif |