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Diffstat (limited to 'nuttx/sched/sem_wait.c')
| -rw-r--r-- | nuttx/sched/sem_wait.c | 216 |
1 files changed, 0 insertions, 216 deletions
diff --git a/nuttx/sched/sem_wait.c b/nuttx/sched/sem_wait.c deleted file mode 100644 index 9dfbaa6c3..000000000 --- a/nuttx/sched/sem_wait.c +++ /dev/null @@ -1,216 +0,0 @@ -/**************************************************************************** - * sched/sem_wait.c - * - * Copyright (C) 2007-2012 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 <stdbool.h> -#include <semaphore.h> -#include <errno.h> -#include <assert.h> -#include <nuttx/arch.h> - -#include "os_internal.h" -#include "sem_internal.h" - -/**************************************************************************** - * Pre-processor Definitions - ****************************************************************************/ - -/**************************************************************************** - * Private Type Declarations - ****************************************************************************/ - -/**************************************************************************** - * Global Variables - ****************************************************************************/ - -/**************************************************************************** - * Private Variables - ****************************************************************************/ - -/**************************************************************************** - * Private Functions - ****************************************************************************/ - -/**************************************************************************** - * Public Functions - ****************************************************************************/ - -/**************************************************************************** - * Name: sem_wait - * - * Description: - * This function attempts to lock the semaphore referenced by 'sem'. If - * the semaphore value is (<=) zero, then the calling task will not return - * until it successfully acquires the lock. - * - * Parameters: - * sem - Semaphore descriptor. - * - * Return Value: - * 0 (OK), or -1 (ERROR) is unsuccessful - * If this function returns -1 (ERROR), then the cause of the failure will - * be reported in 'errno' as: - * - EINVAL: Invalid attempt to get the semaphore - * - EINTR: The wait was interrupted by the receipt of a signal. - * - * Assumptions: - * - ****************************************************************************/ - -int sem_wait(FAR sem_t *sem) -{ - FAR _TCB *rtcb = (FAR _TCB*)g_readytorun.head; - int ret = ERROR; - irqstate_t saved_state; - - /* This API should not be called from interrupt handlers */ - - DEBUGASSERT(up_interrupt_context() == false) - - /* Assume any errors reported are due to invalid arguments. */ - - errno = EINVAL; - - if (sem) - { - /* The following operations must be performed with interrupts - * disabled because sem_post() may be called from an interrupt - * handler. - */ - - saved_state = irqsave(); - - /* Check if the lock is available */ - - if (sem->semcount > 0) - { - /* It is, let the task take the semaphore. */ - - sem->semcount--; - sem_addholder(sem); - rtcb->waitsem = NULL; - ret = OK; - } - - /* The semaphore is NOT available, We will have to block the - * current thread of execution. - */ - - else - { - /* First, verify that the task is not already waiting on a - * semaphore - */ - - if (rtcb->waitsem != NULL) - { - PANIC(OSERR_BADWAITSEM); - } - - /* Handle the POSIX semaphore (but don't set the owner yet) */ - - sem->semcount--; - - /* Save the waited on semaphore in the TCB */ - - rtcb->waitsem = sem; - - /* If priority inheritance is enabled, then check the priority of - * the holder of the semaphore. - */ - -#ifdef CONFIG_PRIORITY_INHERITANCE - /* Disable context switching. The following operations must be - * atomic with regard to the scheduler. - */ - - sched_lock(); - - /* Boost the priority of any threads holding a count on the - * semaphore. - */ - - sem_boostpriority(sem); -#endif - /* Add the TCB to the prioritized semaphore wait queue */ - - errno = 0; - up_block_task(rtcb, TSTATE_WAIT_SEM); - - /* When we resume at this point, either (1) the semaphore has been - * assigned to this thread of execution, or (2) the semaphore wait - * has been interrupted by a signal or a timeout. We can detect these - * latter cases be examining the errno value. - * - * In the event that the semaphore wait was interrupted by a signal or - * a timeout, certain semaphore clean-up operations have already been - * performed (see sem_waitirq.c). Specifically: - * - * - sem_canceled() was called to restore the priority of all threads - * that hold a reference to the semaphore, - * - The semaphore count was decremented, and - * - tcb->waitsem was nullifed. - * - * It is necesaary to do these things in sem_waitirq.c because a long - * time may elapse between the time that the signal was issued and - * this thread is awakened and this leaves a door open to several - * race conditions. - */ - - if (errno != EINTR && errno != ETIMEDOUT) - { - /* Not awakened by a signal or a timeout... We hold the semaphore */ - - sem_addholder(sem); - ret = OK; - } - -#ifdef CONFIG_PRIORITY_INHERITANCE - sched_unlock(); -#endif - } - - /* Interrupts may now be enabled. */ - - irqrestore(saved_state); - } - - return ret; -} |