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process-mutex.c
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1/*
2 * Copyright (c) 2024, Siemens AG.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the copyright holder nor the names of its
14 * contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
20 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
21 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
24 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
26 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
28 * OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31/**
32 * \addtogroup process
33 * @{
34 *
35 * \file
36 * Implementation of Process mutexes.
37 * \author
38 * Konrad Krentz <konrad.krentz@gmail.com>
39 */
40
41#include "sys/process-mutex.h"
42#include <string.h>
43
44/*---------------------------------------------------------------------------*/
45void
46process_mutex_init(process_mutex_t *mutex)
47{
48 memset(mutex, 0, sizeof(*mutex));
49}
50/*---------------------------------------------------------------------------*/
51bool
52process_mutex_try_lock(process_mutex_t *mutex)
53{
54 if(mutex->is_locked) {
55 if(!mutex->waiting_process && !mutex->has_more_waiting_processes) {
56 mutex->waiting_process = PROCESS_CURRENT();
57 } else if(mutex->waiting_process != PROCESS_CURRENT()) {
58 mutex->has_more_waiting_processes = true;
59 mutex->waiting_process = PROCESS_BROADCAST;
60 }
61 return false;
62 } else {
63 mutex->is_locked = true;
64 return true;
65 }
66}
67/*---------------------------------------------------------------------------*/
68void
69process_mutex_unlock(process_mutex_t *mutex)
70{
71 if(mutex->waiting_process || mutex->has_more_waiting_processes) {
72 process_post(mutex->waiting_process, PROCESS_EVENT_UNLOCKED, NULL);
73 mutex->has_more_waiting_processes = false;
74 mutex->waiting_process = NULL;
75 }
76 mutex->is_locked = false;
77}
78/*---------------------------------------------------------------------------*/
79/** @} */
process_post
int process_post(struct process *p, process_event_t ev, process_data_t data)
Post an asynchronous event.
Definition process.c:325
PROCESS_CURRENT
#define PROCESS_CURRENT()
Get a pointer to the currently running process.
Definition process.h:405
process_mutex_init
void process_mutex_init(process_mutex_t *mutex)
Initializes a process mutex.
Definition process-mutex.c:46
process_mutex_try_lock
bool process_mutex_try_lock(process_mutex_t *mutex)
Tries to acquire a process mutex.
Definition process-mutex.c:52
process_mutex_unlock
void process_mutex_unlock(process_mutex_t *mutex)
Unlocks a process mutex.
Definition process-mutex.c:69
process-mutex.h
Header file for Process mutexes.
process_mutex_t
Structure of a process mutex.
Definition process-mutex.h:50