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308 lines
10 KiB
308 lines
10 KiB
/**************************************************************************** |
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* sched/pthread_condtimedwait.c |
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* |
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* Copyright (C) 2007-2009 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <gnutt@nuttx.org> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name NuttX nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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* |
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****************************************************************************/ |
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/**************************************************************************** |
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* Included Files |
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****************************************************************************/ |
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#include <nuttx/config.h> |
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#include <nuttx/compiler.h> |
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#include <stdint.h> |
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#include <unistd.h> |
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#include <pthread.h> |
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#include <signal.h> |
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#include <time.h> |
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#include <errno.h> |
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#include <wdog.h> |
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#include <debug.h> |
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#include "os_internal.h" |
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#include "pthread_internal.h" |
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#include "clock_internal.h" |
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/**************************************************************************** |
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* Definitions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Type Declarations |
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****************************************************************************/ |
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/**************************************************************************** |
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* Global Variables |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Variables |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Functions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Name: pthread_condtimedout |
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* |
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* Description: |
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* This function is called if the timeout elapses before |
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* the condition is signaled. |
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* |
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* Parameters: |
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* argc - the number of arguments (should be 2) |
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* pid - the task ID of the task to wakeup |
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* signo - The signal to use to wake up the task |
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* |
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* Return Value: |
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* None |
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* |
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* Assumptions: |
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* |
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****************************************************************************/ |
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static void pthread_condtimedout(int argc, uint32_t pid, uint32_t signo) |
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{ |
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#ifdef CONFIG_CAN_PASS_STRUCTS |
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union sigval value; |
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/* Send the specified signal to the specified task. */ |
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value.sival_ptr = NULL; |
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(void)sigqueue((int)pid, (int)signo, value); |
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#else |
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(void)sigqueue((int)pid, (int)signo, NULL); |
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#endif |
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} |
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/**************************************************************************** |
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* Public Functions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Name: pthread_cond_timedwait |
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* |
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* Description: |
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* A thread can perform a timed wait on a condition variable. |
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* |
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* Parameters: |
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* cond - the condition variable to wait on |
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* mutex - the mutex that protects the condition variable |
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* abstime - wait until this absolute time |
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* |
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* Return Value: |
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* OK (0) on success; ERROR (-1) on failure with errno |
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* set appropriately. |
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* |
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* Assumptions: |
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* Timing is of resolution 1 msec, with +/-1 millisecond |
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* accuracy. |
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* |
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****************************************************************************/ |
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int pthread_cond_timedwait(FAR pthread_cond_t *cond, FAR pthread_mutex_t *mutex, |
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FAR const struct timespec *abstime) |
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{ |
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WDOG_ID wdog; |
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int ticks; |
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int mypid = (int)getpid(); |
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irqstate_t int_state; |
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int ret = OK; |
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int status; |
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sdbg("cond=0x%p mutex=0x%p abstime=0x%p\n", cond, mutex, abstime); |
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/* Make sure that non-NULL references were provided. */ |
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if (!cond || !mutex) |
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{ |
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ret = EINVAL; |
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} |
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/* Make sure that the caller holds the mutex */ |
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else if (mutex->pid != mypid) |
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{ |
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ret = EPERM; |
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} |
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/* If no wait time is provided, this function degenerates to |
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* the same behavior as pthread_cond_wait(). |
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*/ |
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else if (!abstime) |
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{ |
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ret = pthread_cond_wait(cond, mutex); |
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} |
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else |
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{ |
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/* Create a watchdog */ |
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wdog = wd_create(); |
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if (!wdog) |
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{ |
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ret = EINVAL; |
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} |
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else |
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{ |
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sdbg("Give up mutex...\n"); |
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/* We must disable pre-emption and interrupts here so that |
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* the time stays valid until the wait begins. This adds |
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* complexity because we assure that interrupts and |
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* pre-emption are re-enabled correctly. |
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*/ |
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sched_lock(); |
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int_state = irqsave(); |
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/* Convert the timespec to clock ticks. We must disable pre-emption |
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* here so that this time stays valid until the wait begins. |
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*/ |
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ret = clock_abstime2ticks(CLOCK_REALTIME, abstime, &ticks); |
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if (ret) |
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{ |
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/* Restore interrupts (pre-emption will be enabled when |
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* we fall through the if/then/else |
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*/ |
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irqrestore(int_state); |
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} |
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else |
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{ |
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/* Check the absolute time to wait. If it is now or in the past, then |
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* just return with the timedout condition. |
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*/ |
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if (ticks <= 0) |
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{ |
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/* Restore interrupts and indicate that we have already timed out. |
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* (pre-emption will be enabled when we fall through the |
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* if/then/else |
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*/ |
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irqrestore(int_state); |
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ret = ETIMEDOUT; |
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} |
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else |
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{ |
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/* Give up the mutex */ |
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mutex->pid = 0; |
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ret = pthread_givesemaphore((sem_t*)&mutex->sem); |
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if (ret) |
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{ |
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/* Restore interrupts (pre-emption will be enabled when |
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* we fall through the if/then/else) |
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*/ |
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irqrestore(int_state); |
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} |
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else |
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{ |
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/* Start the watchdog */ |
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wd_start(wdog, ticks, (wdentry_t)pthread_condtimedout, |
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2, (uint32_t)mypid, (uint32_t)SIGCONDTIMEDOUT); |
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/* Take the condition semaphore. Do not restore interrupts |
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* until we return from the wait. This is necessary to |
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* make sure that the watchdog timer and the condition wait |
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* are started atomically. |
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*/ |
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status = sem_wait((sem_t*)&cond->sem); |
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/* Did we get the condition semaphore. */ |
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if (status != OK) |
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{ |
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/* NO.. Handle the special case where the semaphore wait was |
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* awakened by the receipt of a signal -- presumably the |
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* signal posted by pthread_condtimedout(). |
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*/ |
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if (get_errno() == EINTR) |
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{ |
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sdbg("Timedout!\n"); |
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ret = ETIMEDOUT; |
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} |
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else |
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{ |
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ret = EINVAL; |
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} |
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} |
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/* The interrupts stay disabled until after we sample the errno. |
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* This is because when debug is enabled and the console is used |
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* for debug output, then the errno can be altered by interrupt |
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* handling! (bad) |
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*/ |
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irqrestore(int_state); |
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} |
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/* Reacquire the mutex (retaining the ret). */ |
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sdbg("Re-locking...\n"); |
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status = pthread_takesemaphore((sem_t*)&mutex->sem); |
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if (!status) |
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{ |
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mutex->pid = mypid; |
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} |
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else if (!ret) |
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{ |
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ret = status; |
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} |
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} |
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/* Re-enable pre-emption (It is expected that interrupts |
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* have already been re-enabled in the above logic) |
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*/ |
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sched_unlock(); |
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} |
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/* We no longer need the watchdog */ |
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wd_delete(wdog); |
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} |
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} |
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sdbg("Returning %d\n", ret); |
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return ret; |
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} |
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