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Diffstat (limited to 'nuttx/sched/pthread_initialize.c')
| -rw-r--r-- | nuttx/sched/pthread_initialize.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/nuttx/sched/pthread_initialize.c b/nuttx/sched/pthread_initialize.c new file mode 100644 index 000000000..09db1d50e --- /dev/null +++ b/nuttx/sched/pthread_initialize.c @@ -0,0 +1,198 @@ +/**************************************************************************** + * sched/pthread_initialize.c + * + * Copyright (C) 2007-2010 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * 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. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 + * COPYRIGHT OWNER 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. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <stdint.h> +#include <semaphore.h> +#include <errno.h> + +#include "pthread_internal.h" + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Type Declarations + ****************************************************************************/ + +/**************************************************************************** + * Global Variables + ****************************************************************************/ + +/* This is the head of a private singly linked list. It + * is used to retain information about the spawned threads. + */ + +FAR join_t *g_pthread_head = NULL; +FAR join_t *g_pthread_tail = NULL; + +/* Mutually exclusive access to this data set is enforced with + * the following (un-named) semaphore. + */ + +sem_t g_join_semaphore; + +/* This keys track of the number of global keys that have been + * allocated. + */ + +uint8_t g_pthread_num_keys; + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: pthread_initialize + * + * Description: + * This is an internal OS function called only at power-up boot time. + * + * Parameters: + * None + * + * Return Value: + * None + * + * Assumptions: + * + ****************************************************************************/ + +void pthread_initialize(void) +{ + /* Initialize some global variables */ + + g_pthread_head = NULL; + g_pthread_tail = NULL; + g_pthread_num_keys = 0; + + /* Initialize the join semaphore to one (to support one-at- + * a-time access to private data sets). + */ + + (void)sem_init(&g_join_semaphore, 0, 1); +} + +/**************************************************************************** + * Name: pthread_takesemaphore and pthread_givesemaphore + * + * Description: + * Support managed access to the private data sets. + * + * Parameters: + * None + * + * Return Value: + * 0 on success or an ERROR on failure with errno value set to EINVAL. + * Note that the errno EINTR is never returned by this function. + * + * Assumptions: + * + ****************************************************************************/ + +int pthread_takesemaphore(sem_t *sem) +{ + /* Verify input parameters */ + + if (sem) + { + /* Take the semaphore */ + + while (sem_wait(sem) != OK) + { + /* Handle the special case where the semaphore wait was + * awakened by the receipt of a signal. + */ + + if (get_errno() != EINTR) + { + set_errno(EINVAL); + return ERROR; + } + } + return OK; + } + else + { + /* NULL semaphore pointer! */ + + set_errno(EINVAL); + return ERROR; + } +} + +int pthread_givesemaphore(sem_t *sem) +{ + /* Verify input parameters */ + + if (sem) + { + /* Give the semaphore */ + + if (sem_post(sem) == OK) + { + return OK; + } + else + { + /* sem_post() reported an error */ + + set_errno(EINVAL); + return ERROR; + } + } + else + { + /* NULL semaphore pointer! */ + + set_errno(EINVAL); + return ERROR; + } +} + |