1 /*
2  *  Threading abstraction layer
3  *
4  *  Copyright The Mbed TLS Contributors
5  *  SPDX-License-Identifier: Apache-2.0
6  *
7  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
8  *  not use this file except in compliance with the License.
9  *  You may obtain a copy of the License at
10  *
11  *  http://www.apache.org/licenses/LICENSE-2.0
12  *
13  *  Unless required by applicable law or agreed to in writing, software
14  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16  *  See the License for the specific language governing permissions and
17  *  limitations under the License.
18  */
19 
20 /*
21  * Ensure gmtime_r is available even with -std=c99; must be defined before
22  * config.h, which pulls in glibc's features.h. Harmless on other platforms.
23  */
24 #if !defined(_POSIX_C_SOURCE)
25 #define _POSIX_C_SOURCE 200112L
26 #endif
27 
28 #include "common.h"
29 
30 #if defined(MBEDTLS_THREADING_C)
31 
32 #include "mbedtls/threading.h"
33 
34 #if defined(MBEDTLS_HAVE_TIME_DATE) && !defined(MBEDTLS_PLATFORM_GMTIME_R_ALT)
35 
36 #if !defined(_WIN32) && (defined(unix) || \
37     defined(__unix) || defined(__unix__) || (defined(__APPLE__) && \
38     defined(__MACH__)))
39 #include <unistd.h>
40 #endif /* !_WIN32 && (unix || __unix || __unix__ ||
41         * (__APPLE__ && __MACH__)) */
42 
43 #if !( ( defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L ) ||     \
44        ( defined(_POSIX_THREAD_SAFE_FUNCTIONS ) &&                     \
45          _POSIX_THREAD_SAFE_FUNCTIONS >= 200112L ) )
46 /*
47  * This is a convenience shorthand macro to avoid checking the long
48  * preprocessor conditions above. Ideally, we could expose this macro in
49  * platform_util.h and simply use it in platform_util.c, threading.c and
50  * threading.h. However, this macro is not part of the Mbed TLS public API, so
51  * we keep it private by only defining it in this file
52  */
53 
54 #if ! ( defined(_WIN32) && !defined(EFIX64) && !defined(EFI32) )
55 #define THREADING_USE_GMTIME
56 #endif /* ! ( defined(_WIN32) && !defined(EFIX64) && !defined(EFI32) ) */
57 
58 #endif /* !( ( defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L ) ||     \
59              ( defined(_POSIX_THREAD_SAFE_FUNCTIONS ) &&                     \
60                 _POSIX_THREAD_SAFE_FUNCTIONS >= 200112L ) ) */
61 
62 #endif /* MBEDTLS_HAVE_TIME_DATE && !MBEDTLS_PLATFORM_GMTIME_R_ALT */
63 
64 #if defined(MBEDTLS_THREADING_PTHREAD)
threading_mutex_init_pthread(mbedtls_threading_mutex_t * mutex)65 static void threading_mutex_init_pthread( mbedtls_threading_mutex_t *mutex )
66 {
67     if( mutex == NULL )
68         return;
69 
70     /* A nonzero value of is_valid indicates a successfully initialized
71      * mutex. This is a workaround for not being able to return an error
72      * code for this function. The lock/unlock functions return an error
73      * if is_valid is nonzero. The Mbed TLS unit test code uses this field
74      * to distinguish more states of the mutex; see
75      * tests/src/threading_helpers for details. */
76     mutex->is_valid = pthread_mutex_init( &mutex->mutex, NULL ) == 0;
77 }
78 
threading_mutex_free_pthread(mbedtls_threading_mutex_t * mutex)79 static void threading_mutex_free_pthread( mbedtls_threading_mutex_t *mutex )
80 {
81     if( mutex == NULL || !mutex->is_valid )
82         return;
83 
84     (void) pthread_mutex_destroy( &mutex->mutex );
85     mutex->is_valid = 0;
86 }
87 
threading_mutex_lock_pthread(mbedtls_threading_mutex_t * mutex)88 static int threading_mutex_lock_pthread( mbedtls_threading_mutex_t *mutex )
89 {
90     if( mutex == NULL || ! mutex->is_valid )
91         return( MBEDTLS_ERR_THREADING_BAD_INPUT_DATA );
92 
93     if( pthread_mutex_lock( &mutex->mutex ) != 0 )
94         return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
95 
96     return( 0 );
97 }
98 
threading_mutex_unlock_pthread(mbedtls_threading_mutex_t * mutex)99 static int threading_mutex_unlock_pthread( mbedtls_threading_mutex_t *mutex )
100 {
101     if( mutex == NULL || ! mutex->is_valid )
102         return( MBEDTLS_ERR_THREADING_BAD_INPUT_DATA );
103 
104     if( pthread_mutex_unlock( &mutex->mutex ) != 0 )
105         return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
106 
107     return( 0 );
108 }
109 
110 void (*mbedtls_mutex_init)( mbedtls_threading_mutex_t * ) = threading_mutex_init_pthread;
111 void (*mbedtls_mutex_free)( mbedtls_threading_mutex_t * ) = threading_mutex_free_pthread;
112 int (*mbedtls_mutex_lock)( mbedtls_threading_mutex_t * ) = threading_mutex_lock_pthread;
113 int (*mbedtls_mutex_unlock)( mbedtls_threading_mutex_t * ) = threading_mutex_unlock_pthread;
114 
115 /*
116  * With phtreads we can statically initialize mutexes
117  */
118 #define MUTEX_INIT  = { PTHREAD_MUTEX_INITIALIZER, 1 }
119 
120 #endif /* MBEDTLS_THREADING_PTHREAD */
121 
122 #if defined(MBEDTLS_THREADING_ALT)
threading_mutex_fail(mbedtls_threading_mutex_t * mutex)123 static int threading_mutex_fail( mbedtls_threading_mutex_t *mutex )
124 {
125     ((void) mutex );
126     return( MBEDTLS_ERR_THREADING_BAD_INPUT_DATA );
127 }
threading_mutex_dummy(mbedtls_threading_mutex_t * mutex)128 static void threading_mutex_dummy( mbedtls_threading_mutex_t *mutex )
129 {
130     ((void) mutex );
131     return;
132 }
133 
134 void (*mbedtls_mutex_init)( mbedtls_threading_mutex_t * ) = threading_mutex_dummy;
135 void (*mbedtls_mutex_free)( mbedtls_threading_mutex_t * ) = threading_mutex_dummy;
136 int (*mbedtls_mutex_lock)( mbedtls_threading_mutex_t * ) = threading_mutex_fail;
137 int (*mbedtls_mutex_unlock)( mbedtls_threading_mutex_t * ) = threading_mutex_fail;
138 
139 /*
140  * Set functions pointers and initialize global mutexes
141  */
mbedtls_threading_set_alt(void (* mutex_init)(mbedtls_threading_mutex_t *),void (* mutex_free)(mbedtls_threading_mutex_t *),int (* mutex_lock)(mbedtls_threading_mutex_t *),int (* mutex_unlock)(mbedtls_threading_mutex_t *))142 void mbedtls_threading_set_alt( void (*mutex_init)( mbedtls_threading_mutex_t * ),
143                        void (*mutex_free)( mbedtls_threading_mutex_t * ),
144                        int (*mutex_lock)( mbedtls_threading_mutex_t * ),
145                        int (*mutex_unlock)( mbedtls_threading_mutex_t * ) )
146 {
147     mbedtls_mutex_init = mutex_init;
148     mbedtls_mutex_free = mutex_free;
149     mbedtls_mutex_lock = mutex_lock;
150     mbedtls_mutex_unlock = mutex_unlock;
151 
152 #if defined(MBEDTLS_FS_IO)
153     mbedtls_mutex_init( &mbedtls_threading_readdir_mutex );
154 #endif
155 #if defined(THREADING_USE_GMTIME)
156     mbedtls_mutex_init( &mbedtls_threading_gmtime_mutex );
157 #endif
158 }
159 
160 /*
161  * Free global mutexes
162  */
mbedtls_threading_free_alt(void)163 void mbedtls_threading_free_alt( void )
164 {
165 #if defined(MBEDTLS_FS_IO)
166     mbedtls_mutex_free( &mbedtls_threading_readdir_mutex );
167 #endif
168 #if defined(THREADING_USE_GMTIME)
169     mbedtls_mutex_free( &mbedtls_threading_gmtime_mutex );
170 #endif
171 }
172 #endif /* MBEDTLS_THREADING_ALT */
173 
174 /*
175  * Define global mutexes
176  */
177 #ifndef MUTEX_INIT
178 #define MUTEX_INIT
179 #endif
180 #if defined(MBEDTLS_FS_IO)
181 mbedtls_threading_mutex_t mbedtls_threading_readdir_mutex MUTEX_INIT;
182 #endif
183 #if defined(THREADING_USE_GMTIME)
184 mbedtls_threading_mutex_t mbedtls_threading_gmtime_mutex MUTEX_INIT;
185 #endif
186 
187 #endif /* MBEDTLS_THREADING_C */
188