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 /* posix_get_new_sem PORTABLE C */
34 /* 6.1.7 */
35 /* AUTHOR */
36 /* */
37 /* William E. Lamie, Microsoft Corporation */
38 /* */
39 /* DESCRIPTION */
40 /* */
41 /* This function attempts to acquire a ThreadX semaphore from */
42 /* the POSIX semaphore pool. */
43 /* */
44 /* INPUT */
45 /* */
46 /* None */
47 /* */
48 /* OUTPUT */
49 /* */
50 /* tx_sem ThreadX semaphore pointer */
51 /* */
52 /* CALLS */
53 /* */
54 /* None */
55 /* */
56 /* CALLED BY */
57 /* */
58 /* POSIX internal Code */
59 /* */
60 /* RELEASE HISTORY */
61 /* */
62 /* DATE NAME DESCRIPTION */
63 /* */
64 /* 06-02-2021 William E. Lamie Initial Version 6.1.7 */
65 /* */
66 /**************************************************************************/
posix_get_new_sem(VOID)67 TX_SEMAPHORE * posix_get_new_sem(VOID)
68 {
69
70 ULONG i;
71 TX_SEMAPHORE *tx_sem;
72 sem_t *sem_ptr;
73
74 /* Loop through the list of semaphores - */
75 /* try to find one that is not "in use" */
76 /* Start out pessimistic - assume we won't find a match. */
77 tx_sem = (TX_SEMAPHORE *)0;
78
79 /* Search the semaphore pool for an available semaphore. */
80 for (i = 0, sem_ptr = &(posix_sem_pool[0]);
81 i < SEM_NSEMS_MAX;
82 i++, sem_ptr++)
83 {
84 /* Make sure the semaphore is not already "in use". */
85 if (sem_ptr->in_use == TX_FALSE)
86 {
87
88 /* Found one! */
89 tx_sem = MAKE_TX_SEM(sem_ptr);
90
91 /* This semaphore is now in use. */
92 sem_ptr->in_use = TX_TRUE;
93
94 break;
95 }
96 }
97 return(tx_sem);
98 }
99
