Initial commit: TXW82x FPV v2.7.0.7-42229 SDK + project sources

sdk/lib/posix/pthread_rwlock.c

@@ -0,0 +1,343 @@
+#include "sys_config.h"
+#include "typesdef.h"
+#include "errno.h"
+#include "osal/semaphore.h"
+#include "osal/task.h"
+#include "osal/string.h"
+#include "osal/timer.h"
+#include "osal/mutex.h"
+#include "lib/common/rbuffer.h"
+#include "lib/posix/pthread.h"
+
+#ifdef TXWSDK_POSIX
+
+int pthread_rwlockattr_init(pthread_rwlockattr_t *attr)
+{
+    if (!attr) {
+        return -EINVAL;
+    }
+
+    *attr = PTHREAD_PROCESS_PRIVATE;
+    return 0;
+}
+
+int pthread_rwlockattr_destroy(pthread_rwlockattr_t *attr)
+{
+    if (!attr) {
+        return -EINVAL;
+    }
+    return 0;
+}
+
+int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *attr,
+                                  int                        *pshared)
+{
+    if (!attr || !pshared) {
+        return -EINVAL;
+    }
+    *pshared = PTHREAD_PROCESS_PRIVATE;
+    return 0;
+}
+
+int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *attr, int pshared)
+{
+    if (!attr || pshared != PTHREAD_PROCESS_PRIVATE) {
+        return -EINVAL;
+    }
+    return 0;
+}
+
+int pthread_rwlock_init(pthread_rwlock_t           *rwlock,
+                        const pthread_rwlockattr_t *attr)
+{
+    if (!rwlock) {
+        return -EINVAL;
+    }
+
+    rwlock->attr = PTHREAD_PROCESS_PRIVATE;
+    pthread_mutex_init(&(rwlock->rw_mutex), NULL);
+    pthread_cond_init(&(rwlock->rw_condreaders), NULL);
+    pthread_cond_init(&(rwlock->rw_condwriters), NULL);
+
+    rwlock->rw_nwaitwriters = 0;
+    rwlock->rw_nwaitreaders = 0;
+    rwlock->rw_refcount = 0;
+    return 0;
+}
+
+int pthread_rwlock_destroy(pthread_rwlock_t *rwlock)
+{
+    int result;
+
+    if (!rwlock) {
+        return -EINVAL;
+    }
+
+    if (rwlock->attr == -1) {
+        return 0; /* rwlock is not initialized */
+    }
+
+    if ((result = pthread_mutex_lock(&rwlock->rw_mutex)) != 0) {
+        return (result);
+    }
+
+    if (rwlock->rw_refcount != 0 ||
+        rwlock->rw_nwaitreaders != 0 ||
+        rwlock->rw_nwaitwriters != 0) {
+        return -EBUSY;
+    } else {
+        pthread_cond_destroy(&rwlock->rw_condreaders);
+        pthread_cond_destroy(&rwlock->rw_condwriters);
+    }
+
+    pthread_mutex_unlock(&rwlock->rw_mutex);
+    if (result == 0) {
+        pthread_mutex_destroy(&rwlock->rw_mutex);
+    }
+    return result;
+}
+
+int pthread_rwlock_rdlock(pthread_rwlock_t *rwlock)
+{
+    int result;
+
+    if (!rwlock) {
+        return -EINVAL;
+    }
+
+    if (rwlock->attr == -1) {
+        pthread_rwlock_init(rwlock, NULL);
+    }
+
+    if ((result = pthread_mutex_lock(&rwlock->rw_mutex)) != 0) {
+        return (result);
+    }
+
+    /* give preference to waiting writers */
+    while (rwlock->rw_refcount < 0 || rwlock->rw_nwaitwriters > 0) {
+        rwlock->rw_nwaitreaders++;
+        /* rw_mutex will be released when waiting for rw_condreaders */
+        result = pthread_cond_wait(&rwlock->rw_condreaders, &rwlock->rw_mutex);
+        /* rw_mutex should have been taken again when returned from waiting */
+        rwlock->rw_nwaitreaders--;
+        if (result != 0) { /* wait error */
+            break;
+        }
+    }
+
+    /* another reader has a read lock */
+    if (result == 0) {
+        rwlock->rw_refcount++;
+    }
+
+    pthread_mutex_unlock(&rwlock->rw_mutex);
+
+    return (result);
+}
+
+int pthread_rwlock_tryrdlock(pthread_rwlock_t *rwlock)
+{
+    int result;
+
+    if (!rwlock) {
+        return -EINVAL;
+    }
+
+    if (rwlock->attr == -1) {
+        pthread_rwlock_init(rwlock, NULL);
+    }
+
+    if ((result = pthread_mutex_lock(&rwlock->rw_mutex)) != 0) {
+        return (result);
+    }
+
+    if (rwlock->rw_refcount < 0 || rwlock->rw_nwaitwriters > 0) {
+        result = -EBUSY; /* held by a writer or waiting writers */
+    } else {
+        rwlock->rw_refcount++; /* increment count of reader locks */
+    }
+
+    pthread_mutex_unlock(&rwlock->rw_mutex);
+
+    return (result);
+}
+
+int pthread_rwlock_timedrdlock(pthread_rwlock_t      *rwlock,
+                               const struct timespec *abstime)
+{
+    int result;
+
+    if (!rwlock) {
+        return -EINVAL;
+    }
+
+    if (rwlock->attr == -1) {
+        pthread_rwlock_init(rwlock, NULL);
+    }
+
+    if ((result = pthread_mutex_lock(&rwlock->rw_mutex)) != 0) {
+        return (result);
+    }
+
+    /* give preference to waiting writers */
+    while (rwlock->rw_refcount < 0 || rwlock->rw_nwaitwriters > 0) {
+        rwlock->rw_nwaitreaders++;
+        /* rw_mutex will be released when waiting for rw_condreaders */
+        result = pthread_cond_timedwait(&rwlock->rw_condreaders, &rwlock->rw_mutex, abstime);
+        /* rw_mutex should have been taken again when returned from waiting */
+        rwlock->rw_nwaitreaders--;
+        if (result != 0) {
+            break;
+        }
+    }
+
+    /* another reader has a read lock */
+    if (result == 0) {
+        rwlock->rw_refcount++;
+    }
+
+    pthread_mutex_unlock(&rwlock->rw_mutex);
+
+    return (result);
+}
+
+int pthread_rwlock_timedwrlock(pthread_rwlock_t      *rwlock,
+                               const struct timespec *abstime)
+{
+    int result;
+
+    if (!rwlock) {
+        return -EINVAL;
+    }
+
+    if (rwlock->attr == -1) {
+        pthread_rwlock_init(rwlock, NULL);
+    }
+
+    if ((result = pthread_mutex_lock(&rwlock->rw_mutex)) != 0) {
+        return (result);
+    }
+
+    while (rwlock->rw_refcount != 0) {
+        rwlock->rw_nwaitwriters++;
+        /* rw_mutex will be released when waiting for rw_condwriters */
+        result = pthread_cond_timedwait(&rwlock->rw_condwriters, &rwlock->rw_mutex, abstime);
+        /* rw_mutex should have been taken again when returned from waiting */
+        rwlock->rw_nwaitwriters--;
+
+        if (result != 0) {
+            break;
+        }
+    }
+
+    if (result == 0) {
+        rwlock->rw_refcount = -1;
+    }
+
+    pthread_mutex_unlock(&rwlock->rw_mutex);
+
+    return (result);
+}
+
+int pthread_rwlock_trywrlock(pthread_rwlock_t *rwlock)
+{
+    int result;
+
+    if (!rwlock) {
+        return -EINVAL;
+    }
+
+    if (rwlock->attr == -1) {
+        pthread_rwlock_init(rwlock, NULL);
+    }
+
+    if ((result = pthread_mutex_lock(&rwlock->rw_mutex)) != 0) {
+        return (result);
+    }
+
+    if (rwlock->rw_refcount != 0) {
+        result = -EBUSY; /* held by either writer or reader(s) */
+    } else {
+        rwlock->rw_refcount = -1; /* available, indicate a writer has it */
+
+    }
+    pthread_mutex_unlock(&rwlock->rw_mutex);
+
+    return (result);
+}
+
+int pthread_rwlock_unlock(pthread_rwlock_t *rwlock)
+{
+    int result;
+
+    if (!rwlock) {
+        return -EINVAL;
+    }
+
+    if (rwlock->attr == -1) {
+        pthread_rwlock_init(rwlock, NULL);
+    }
+
+    if ((result = pthread_mutex_lock(&rwlock->rw_mutex)) != 0) {
+        return (result);
+    }
+
+    if (rwlock->rw_refcount > 0) {
+        rwlock->rw_refcount--; /* releasing a reader */
+    } else if (rwlock->rw_refcount == -1) {
+        rwlock->rw_refcount = 0; /* releasing a writer */
+    }
+
+    /* give preference to waiting writers over waiting readers */
+    if (rwlock->rw_nwaitwriters > 0) {
+        if (rwlock->rw_refcount == 0) {
+            result = pthread_cond_signal(&rwlock->rw_condwriters);
+        }
+    } else if (rwlock->rw_nwaitreaders > 0) {
+        result = pthread_cond_broadcast(&rwlock->rw_condreaders);
+    }
+
+    pthread_mutex_unlock(&rwlock->rw_mutex);
+
+    return (result);
+}
+
+int pthread_rwlock_wrlock(pthread_rwlock_t *rwlock)
+{
+    int result;
+
+    if (!rwlock) {
+        return -EINVAL;
+    }
+
+    if (rwlock->attr == -1) {
+        pthread_rwlock_init(rwlock, NULL);
+    }
+
+    if ((result = pthread_mutex_lock(&rwlock->rw_mutex)) != 0) {
+        return (result);
+    }
+
+    while (rwlock->rw_refcount != 0) {
+        rwlock->rw_nwaitwriters++;
+        /* rw_mutex will be released when waiting for rw_condwriters */
+        result = pthread_cond_wait(&rwlock->rw_condwriters, &rwlock->rw_mutex);
+        /* rw_mutex should have been taken again when returned from waiting */
+        rwlock->rw_nwaitwriters--;
+
+        if (result != 0) {
+            break;
+        }
+    }
+
+    if (result == 0) {
+        rwlock->rw_refcount = -1;
+    }
+
+    pthread_mutex_unlock(&rwlock->rw_mutex);
+
+    return (result);
+}
+
+#endif
+