1 /***************************************************************************
2 * Copyright (c) 2024 Microsoft Corporation
3 *
4 * This program and the accompanying materials are made available under the
5 * terms of the MIT License which is available at
6 * https://opensource.org/licenses/MIT.
7 *
8 * SPDX-License-Identifier: MIT
9 **************************************************************************/
10
11
12 /**************************************************************************/
13 /**************************************************************************/
14 /** */
15 /** POSIX wrapper for THREADX */
16 /** */
17 /** */
18 /** */
19 /**************************************************************************/
20 /**************************************************************************/
21
22 /* Include necessary system files. */
23
24 #include "tx_api.h" /* Threadx API */
25 #include "pthread.h" /* Posix API */
26 #include "px_int.h" /* Posix helper functions */
27
28
29 /**************************************************************************/
30 /* */
31 /* FUNCTION RELEASE */
32 /* */
33 /* pthread_cond_timedwait PORTABLE C */
34 /* 6.1.7 */
35 /* AUTHOR */
36 /* */
37 /* William E. Lamie, Microsoft Corporation */
38 /* */
39 /* DESCRIPTION */
40 /* */
41 /* This function shall block on a condition variable. They shall be */
42 /* called with mutex locked by the calling thread or undefined behavior*/
43 /* results.These functions atomically release the mutex and cause the */
44 /* calling thread to block on the condition variable cond; atomically */
45 /* here means ��atomically with respect to access by another */
46 /* thread to the mutex and then the request for semaphore. */
47 /* */
48 /* Upon successful return, the mutex shall have been locked and shall */
49 /* be owned by the calling thread. */
50 /* */
51 /* Upon successful return, the mutex shall have been locked and shall */
52 /* be owned by the calling thread. */
53 /* When using condition variables there is always a Boolean predicate */
54 /* involving shared variables associated with each condition wait that */
55 /* is true if the thread should proceed. Spurious wakeups from the */
56 /* pthread_cond_timedwait or pthread_cond_wait functions may occur. */
57 /* Since the return from pthread_cond_timedwait or pthread_cond_wait */
58 /* does not imply anything about the value of this predicate, the */
59 /* predicate should be re-evaluated upon such return. The effect of */
60 /* using more than one mutex for concurrent pthread_cond_timedwait or */
61 /* pthread_cond_wait operations on the same condition variable is */
62 /* undefined; that is, a condition variable becomes bound to a unique */
63 /* mutex when a thread waits on the condition variable, and this */
64 /* (dynamic) binding shall end when the wait returns. */
65 /* */
66 /* INPUT */
67 /* */
68 /* cond condition variable */
69 /* mutex mutex to be associated with condition */
70 /* variable */
71 /* abstime time interval for wait */
72 /* */
73 /* OUTPUT */
74 /* */
75 /* OK if succesfull */
76 /* ERROR in case of any error */
77 /* */
78 /* CALLS */
79 /* */
80 /* pthread_mutex_unlock unlocks the mutex held by the caller */
81 /* tx_semaphore_get try to get sempaphore internal to cond */
82 /* tx_semaphore_prioritize prioritize all suspended pthreads */
83 /* pthread_mutex_lock lock the mutex */
84 /* */
85 /* CALLED BY */
86 /* */
87 /* Application Code */
88 /* */
89 /* RELEASE HISTORY */
90 /* */
91 /* DATE NAME DESCRIPTION */
92 /* */
93 /* 06-02-2021 William Lamie Initial Version 6.1.7 */
94 /* */
95 /**************************************************************************/
pthread_cond_timedwait(pthread_cond_t * cond,pthread_mutex_t * mutex,struct timespec * abstime)96 INT pthread_cond_timedwait(pthread_cond_t *cond,pthread_mutex_t *mutex,
97 struct timespec *abstime)
98 {
99
100 TX_SEMAPHORE *semaphore_ptr;
101 ULONG wait_option;
102 UINT status;
103 UINT old_threshold,dummy;
104 TX_THREAD *thread;
105
106 /* Find the current thread. */
107 thread = tx_thread_identify();
108
109 /* Raise its preemption threshold so it does not get descheduled. */
110 tx_thread_preemption_change(thread,0,&old_threshold);
111
112 pthread_mutex_unlock(mutex);
113 semaphore_ptr = (&( cond->cond_semaphore ));
114
115 wait_option = posix_abs_time_to_rel_ticks(abstime);
116
117 status = tx_semaphore_get(semaphore_ptr, wait_option);
118
119 /* Restore original preemption threshold */
120 tx_thread_preemption_change(thread, old_threshold, &dummy);
121
122 if( status == TX_NO_INSTANCE)
123 {
124 posix_errno = ETIMEDOUT;
125 posix_set_pthread_errno(ETIMEDOUT);
126 return(ETIMEDOUT);
127 }
128 else if ( status != TX_SUCCESS)
129 {
130 posix_errno = EINVAL;
131 posix_set_pthread_errno(EINVAL);
132 return(EINVAL);
133 }
134 status = tx_semaphore_prioritize(semaphore_ptr);
135 if (status != TX_SUCCESS)
136 {
137 posix_errno = EINVAL;
138 posix_set_pthread_errno(EINVAL);
139 return(EINVAL);
140 }
141 pthread_mutex_lock(mutex);
142
143 return(OK);
144 }
145
