1 /**************************************************************************/
2 /* */
3 /* Copyright (c) Microsoft Corporation. All rights reserved. */
4 /* */
5 /* This software is licensed under the Microsoft Software License */
6 /* Terms for Microsoft Azure RTOS. Full text of the license can be */
7 /* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
8 /* and in the root directory of this software. */
9 /* */
10 /**************************************************************************/
11
12
13 /**************************************************************************/
14 /**************************************************************************/
15 /** */
16 /** POSIX wrapper for THREADX */
17 /** */
18 /** */
19 /** */
20 /**************************************************************************/
21 /**************************************************************************/
22
23 /* Include necessary system files. */
24
25 #include "tx_api.h" /* Threadx API */
26 #include "pthread.h" /* Posix API */
27 #include "px_int.h" /* Posix helper functions */
28
29
30 /**************************************************************************/
31 /* */
32 /* FUNCTION RELEASE */
33 /* */
34 /* pthread_cond_broadcast PORTABLE C */
35 /* 6.1.7 */
36 /* AUTHOR */
37 /* */
38 /* William E. Lamie, Microsoft Corporation */
39 /* */
40 /* DESCRIPTION */
41 /* */
42 /* These functions shall unblock all threads currently blocked on a */
43 /* specified condition variable cond. */
44 /* If more than one thread is blocked on a condition variable, */
45 /* the scheduling policy shall determine the order in which threads are*/
46 /* unblocked. When each thread unblocked as a result of this function */
47 /* call returns from its call to pthread_cond_wait or */
48 /* pthread_cond_timedwait, the thread shall own the mutex with which it*/
49 /* called pthread_cond_wait or pthread_cond_timedwait. The thread(s) */
50 /* that are unblocked shall contend for the mutex according to the */
51 /* scheduling policy (if applicable), and as if each had called */
52 /* pthread_mutex_lock.The pthread_cond_broadcast function may be called*/
53 /* by a thread whether or not it currently owns the mutex that threads */
54 /* calling pthread_cond_wait or pthread_cond_timedwait have associated */
55 /* with the condition variable during their waits; however, */
56 /* if predictable scheduling behavior is required, then that mutex */
57 /* shall be locked by the thread calling pthread_cond_broadcast. */
58 /* The pthread_cond_broadcast function shall have no effect if there */
59 /* are no threads currently blocked on cond. */
60 /* */
61 /* INPUT */
62 /* */
63 /* cond condition variable */
64 /* */
65 /* OUTPUT */
66 /* */
67 /* Ok if successful */
68 /* Error in case of any errors */
69 /* */
70 /* CALLS */
71 /* */
72 /* tx_semaphore_prioritize line up pthreads waiting at semaphore*/
73 /* tx_thread_identify to check which pthread? */
74 /* tx_thread_preemption_change to disable thread preemption */
75 /* tx_semaphore_put ThreadX semaphore put service */
76 /* tx_thread_preemption_change to enable thread preemption */
77 /* */
78 /* CALLED BY */
79 /* */
80 /* Application Code */
81 /* */
82 /* RELEASE HISTORY */
83 /* */
84 /* DATE NAME DESCRIPTION */
85 /* */
86 /* 06-02-2021 William E. Lamie Initial Version 6.1.7 */
87 /* */
88 /**************************************************************************/
pthread_cond_broadcast(pthread_cond_t * cond)89 INT pthread_cond_broadcast(pthread_cond_t *cond)
90 {
91
92 TX_SEMAPHORE *semaphore_ptr;
93 TX_THREAD *thread;
94 UINT status;
95 ULONG sem_count;
96 UINT old_threshold,dummy;
97
98
99 /* Get the condition variable's internal semaphore. */
100 /* Simply convert the condition variable control block into a semaphore a cast */
101 semaphore_ptr = (&( cond->cond_semaphore ));
102 sem_count = semaphore_ptr->tx_semaphore_suspended_count;
103
104 if (!sem_count)
105 return(OK);
106
107 status = tx_semaphore_prioritize(semaphore_ptr);
108
109 if ( status != TX_SUCCESS)
110 {
111 posix_errno = EINVAL;
112 posix_set_pthread_errno(EINVAL);
113 return(EINVAL);
114 }
115
116 /* get to know about current thread */
117 thread = tx_thread_identify();
118
119 /* Got the current thread , now raise its preemption threshold */
120 /* that way the current thread does not get descheduled when */
121 /* threads with higher priority are activated */
122 tx_thread_preemption_change(thread,0,&old_threshold);
123
124 while( sem_count)
125 {
126
127 status = tx_semaphore_put(semaphore_ptr);
128 if ( status != TX_SUCCESS)
129 {
130
131 /* restore changed preemption threshold */
132 tx_thread_preemption_change(thread,old_threshold,&dummy);
133
134 posix_errno = EINVAL;
135
136 posix_set_pthread_errno(EINVAL);
137
138 return(EINVAL);
139 }
140
141 sem_count--;
142 }
143
144 /* restore changed preemption threshold */
145 tx_thread_preemption_change(thread,old_threshold,&dummy);
146 return(OK);
147 }
148
