1 /**
2  * \file threading.h
3  *
4  * \brief Threading abstraction layer
5  */
6 /*
7  *  Copyright The Mbed TLS Contributors
8  *  SPDX-License-Identifier: Apache-2.0
9  *
10  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
11  *  not use this file except in compliance with the License.
12  *  You may obtain a copy of the License at
13  *
14  *  http://www.apache.org/licenses/LICENSE-2.0
15  *
16  *  Unless required by applicable law or agreed to in writing, software
17  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
18  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19  *  See the License for the specific language governing permissions and
20  *  limitations under the License.
21  */
22 #ifndef MBEDTLS_THREADING_H
23 #define MBEDTLS_THREADING_H
24 #include "mbedtls/private_access.h"
25 
26 #include "mbedtls/build_info.h"
27 
28 #include <stdlib.h>
29 
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33 
34 /** Bad input parameters to function. */
35 #define MBEDTLS_ERR_THREADING_BAD_INPUT_DATA              -0x001C
36 /** Locking / unlocking / free failed with error code. */
37 #define MBEDTLS_ERR_THREADING_MUTEX_ERROR                 -0x001E
38 
39 #if defined(MBEDTLS_THREADING_PTHREAD)
40 #include <pthread.h>
41 typedef struct mbedtls_threading_mutex_t
42 {
43     pthread_mutex_t MBEDTLS_PRIVATE(mutex);
44     /* is_valid is 0 after a failed init or a free, and nonzero after a
45      * successful init. This field is not considered part of the public
46      * API of Mbed TLS and may change without notice. */
47     char MBEDTLS_PRIVATE(is_valid);
48 } mbedtls_threading_mutex_t;
49 #endif
50 
51 #if defined(MBEDTLS_THREADING_ALT)
52 /* You should define the mbedtls_threading_mutex_t type in your header */
53 #include "threading_alt.h"
54 
55 /**
56  * \brief           Set your alternate threading implementation function
57  *                  pointers and initialize global mutexes. If used, this
58  *                  function must be called once in the main thread before any
59  *                  other mbed TLS function is called, and
60  *                  mbedtls_threading_free_alt() must be called once in the main
61  *                  thread after all other mbed TLS functions.
62  *
63  * \note            mutex_init() and mutex_free() don't return a status code.
64  *                  If mutex_init() fails, it should leave its argument (the
65  *                  mutex) in a state such that mutex_lock() will fail when
66  *                  called with this argument.
67  *
68  * \param mutex_init    the init function implementation
69  * \param mutex_free    the free function implementation
70  * \param mutex_lock    the lock function implementation
71  * \param mutex_unlock  the unlock function implementation
72  */
73 void mbedtls_threading_set_alt( void (*mutex_init)( mbedtls_threading_mutex_t * ),
74                        void (*mutex_free)( mbedtls_threading_mutex_t * ),
75                        int (*mutex_lock)( mbedtls_threading_mutex_t * ),
76                        int (*mutex_unlock)( mbedtls_threading_mutex_t * ) );
77 
78 /**
79  * \brief               Free global mutexes.
80  */
81 void mbedtls_threading_free_alt( void );
82 #endif /* MBEDTLS_THREADING_ALT */
83 
84 #if defined(MBEDTLS_THREADING_C)
85 /*
86  * The function pointers for mutex_init, mutex_free, mutex_ and mutex_unlock
87  *
88  * All these functions are expected to work or the result will be undefined.
89  */
90 extern void (*mbedtls_mutex_init)( mbedtls_threading_mutex_t *mutex );
91 extern void (*mbedtls_mutex_free)( mbedtls_threading_mutex_t *mutex );
92 extern int (*mbedtls_mutex_lock)( mbedtls_threading_mutex_t *mutex );
93 extern int (*mbedtls_mutex_unlock)( mbedtls_threading_mutex_t *mutex );
94 
95 /*
96  * Global mutexes
97  */
98 #if defined(MBEDTLS_FS_IO)
99 extern mbedtls_threading_mutex_t mbedtls_threading_readdir_mutex;
100 #endif
101 
102 #if defined(MBEDTLS_HAVE_TIME_DATE) && !defined(MBEDTLS_PLATFORM_GMTIME_R_ALT)
103 /* This mutex may or may not be used in the default definition of
104  * mbedtls_platform_gmtime_r(), but in order to determine that,
105  * we need to check POSIX features, hence modify _POSIX_C_SOURCE.
106  * With the current approach, this declaration is orphaned, lacking
107  * an accompanying definition, in case mbedtls_platform_gmtime_r()
108  * doesn't need it, but that's not a problem. */
109 extern mbedtls_threading_mutex_t mbedtls_threading_gmtime_mutex;
110 #endif /* MBEDTLS_HAVE_TIME_DATE && !MBEDTLS_PLATFORM_GMTIME_R_ALT */
111 
112 #endif /* MBEDTLS_THREADING_C */
113 
114 #ifdef __cplusplus
115 }
116 #endif
117 
118 #endif /* threading.h */
119