9d433c89a2
In the Zephyr implementation, `sem_timedwait()` uses a potentially wildly different timebase for comparison via `k_uptime_get()` (uptime in ms). The standard specifies `CLOCK_REALTIME`. However, the real-time clock can be modified to an arbitrary value via clock_settime() and there is no guarantee that it will always reflect uptime. This change ensures that `sem_timedwait()` uses a more consistent timebase for comparison. Fixes #46807 Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>
151 lines
2.3 KiB
C
151 lines
2.3 KiB
C
/*
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* Copyright (c) 2018 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <errno.h>
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#include <zephyr/posix/pthread.h>
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/**
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* @brief Destroy semaphore.
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*
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* see IEEE 1003.1
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*/
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int sem_destroy(sem_t *semaphore)
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{
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if (semaphore == NULL) {
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errno = EINVAL;
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return -1;
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}
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if (k_sem_count_get(semaphore)) {
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errno = EBUSY;
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return -1;
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}
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k_sem_reset(semaphore);
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return 0;
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}
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/**
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* @brief Get value of semaphore.
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*
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* See IEEE 1003.1
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*/
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int sem_getvalue(sem_t *semaphore, int *value)
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{
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if (semaphore == NULL) {
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errno = EINVAL;
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return -1;
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}
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*value = (int) k_sem_count_get(semaphore);
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return 0;
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}
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/**
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* @brief Initialize semaphore.
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*
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* See IEEE 1003.1
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*/
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int sem_init(sem_t *semaphore, int pshared, unsigned int value)
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{
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if (value > CONFIG_SEM_VALUE_MAX) {
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errno = EINVAL;
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return -1;
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}
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/*
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* Zephyr has no concept of process, so only thread shared
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* semaphore makes sense in here.
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*/
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__ASSERT(pshared == 0, "pshared should be 0");
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k_sem_init(semaphore, value, CONFIG_SEM_VALUE_MAX);
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return 0;
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}
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/**
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* @brief Unlock a semaphore.
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*
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* See IEEE 1003.1
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*/
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int sem_post(sem_t *semaphore)
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{
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if (semaphore == NULL) {
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errno = EINVAL;
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return -1;
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}
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k_sem_give(semaphore);
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return 0;
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}
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/**
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* @brief Try time limited locking a semaphore.
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*
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* See IEEE 1003.1
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*/
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int sem_timedwait(sem_t *semaphore, struct timespec *abstime)
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{
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int32_t timeout;
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struct timespec current;
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int64_t current_ms, abstime_ms;
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__ASSERT(abstime, "abstime pointer NULL");
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if ((abstime->tv_sec < 0) || (abstime->tv_nsec >= NSEC_PER_SEC)) {
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errno = EINVAL;
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return -1;
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}
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if (clock_gettime(CLOCK_REALTIME, ¤t) < 0) {
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return -1;
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}
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abstime_ms = (int64_t)_ts_to_ms(abstime);
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current_ms = (int64_t)_ts_to_ms(¤t);
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if (abstime_ms <= current_ms) {
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timeout = 0;
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} else {
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timeout = (int32_t)(abstime_ms - current_ms);
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}
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if (k_sem_take(semaphore, K_MSEC(timeout))) {
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errno = ETIMEDOUT;
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return -1;
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}
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return 0;
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}
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/**
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* @brief Lock a semaphore if not taken.
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*
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* See IEEE 1003.1
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*/
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int sem_trywait(sem_t *semaphore)
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{
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if (k_sem_take(semaphore, K_NO_WAIT) == -EBUSY) {
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errno = EAGAIN;
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return -1;
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} else {
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return 0;
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}
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}
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/**
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* @brief Lock a semaphore.
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*
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* See IEEE 1003.1
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*/
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int sem_wait(sem_t *semaphore)
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{
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/* With K_FOREVER, may return only success. */
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(void)k_sem_take(semaphore, K_FOREVER);
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return 0;
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}
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