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 OR GPL-2.0-or-later
9  */
10 #ifndef MBEDTLS_THREADING_H
11 #define MBEDTLS_THREADING_H
12 #include "mbedtls/private_access.h"
13 
14 #include "mbedtls/build_info.h"
15 
16 #include <stdlib.h>
17 
18 #ifdef __cplusplus
19 extern "C" {
20 #endif
21 
22 /** Bad input parameters to function. */
23 #define MBEDTLS_ERR_THREADING_BAD_INPUT_DATA              -0x001C
24 /** Locking / unlocking / free failed with error code. */
25 #define MBEDTLS_ERR_THREADING_MUTEX_ERROR                 -0x001E
26 
27 #if defined(MBEDTLS_THREADING_PTHREAD)
28 #include <pthread.h>
29 typedef struct mbedtls_threading_mutex_t {
30     pthread_mutex_t MBEDTLS_PRIVATE(mutex);
31 
32     /* WARNING - state should only be accessed when holding the mutex lock in
33      * tests/src/threading_helpers.c, otherwise corruption can occur.
34      * state will be 0 after a failed init or a free, and nonzero after a
35      * successful init. This field is for testing only and thus not considered
36      * part of the public API of Mbed TLS and may change without notice.*/
37     char MBEDTLS_PRIVATE(state);
38 
39 } mbedtls_threading_mutex_t;
40 #endif
41 
42 #if defined(MBEDTLS_THREADING_ALT)
43 /* You should define the mbedtls_threading_mutex_t type in your header */
44 #include "threading_alt.h"
45 
46 /**
47  * \brief           Set your alternate threading implementation function
48  *                  pointers and initialize global mutexes. If used, this
49  *                  function must be called once in the main thread before any
50  *                  other Mbed TLS function is called, and
51  *                  mbedtls_threading_free_alt() must be called once in the main
52  *                  thread after all other Mbed TLS functions.
53  *
54  * \note            mutex_init() and mutex_free() don't return a status code.
55  *                  If mutex_init() fails, it should leave its argument (the
56  *                  mutex) in a state such that mutex_lock() will fail when
57  *                  called with this argument.
58  *
59  * \param mutex_init    the init function implementation
60  * \param mutex_free    the free function implementation
61  * \param mutex_lock    the lock function implementation
62  * \param mutex_unlock  the unlock function implementation
63  */
64 void mbedtls_threading_set_alt(void (*mutex_init)(mbedtls_threading_mutex_t *),
65                                void (*mutex_free)(mbedtls_threading_mutex_t *),
66                                int (*mutex_lock)(mbedtls_threading_mutex_t *),
67                                int (*mutex_unlock)(mbedtls_threading_mutex_t *));
68 
69 /**
70  * \brief               Free global mutexes.
71  */
72 void mbedtls_threading_free_alt(void);
73 #endif /* MBEDTLS_THREADING_ALT */
74 
75 #if defined(MBEDTLS_THREADING_C)
76 /*
77  * The function pointers for mutex_init, mutex_free, mutex_ and mutex_unlock
78  *
79  * All these functions are expected to work or the result will be undefined.
80  */
81 extern void (*mbedtls_mutex_init)(mbedtls_threading_mutex_t *mutex);
82 extern void (*mbedtls_mutex_free)(mbedtls_threading_mutex_t *mutex);
83 extern int (*mbedtls_mutex_lock)(mbedtls_threading_mutex_t *mutex);
84 extern int (*mbedtls_mutex_unlock)(mbedtls_threading_mutex_t *mutex);
85 
86 /*
87  * Global mutexes
88  */
89 #if defined(MBEDTLS_FS_IO)
90 extern mbedtls_threading_mutex_t mbedtls_threading_readdir_mutex;
91 #endif
92 
93 #if defined(MBEDTLS_HAVE_TIME_DATE) && !defined(MBEDTLS_PLATFORM_GMTIME_R_ALT)
94 /* This mutex may or may not be used in the default definition of
95  * mbedtls_platform_gmtime_r(), but in order to determine that,
96  * we need to check POSIX features, hence modify _POSIX_C_SOURCE.
97  * With the current approach, this declaration is orphaned, lacking
98  * an accompanying definition, in case mbedtls_platform_gmtime_r()
99  * doesn't need it, but that's not a problem. */
100 extern mbedtls_threading_mutex_t mbedtls_threading_gmtime_mutex;
101 #endif /* MBEDTLS_HAVE_TIME_DATE && !MBEDTLS_PLATFORM_GMTIME_R_ALT */
102 
103 #if defined(MBEDTLS_PSA_CRYPTO_C)
104 /*
105  * A mutex used to make the PSA subsystem thread safe.
106  *
107  * key_slot_mutex protects the registered_readers and
108  * state variable for all key slots in &global_data.key_slots.
109  *
110  * This mutex must be held when any read from or write to a state or
111  * registered_readers field is performed, i.e. when calling functions:
112  * psa_key_slot_state_transition(), psa_register_read(), psa_unregister_read(),
113  * psa_key_slot_has_readers() and psa_wipe_key_slot(). */
114 extern mbedtls_threading_mutex_t mbedtls_threading_key_slot_mutex;
115 
116 /*
117  * A mutex used to make the non-rng PSA global_data struct members thread safe.
118  *
119  * This mutex must be held when reading or writing to any of the PSA global_data
120  * structure members, other than the rng_state or rng struct. */
121 extern mbedtls_threading_mutex_t mbedtls_threading_psa_globaldata_mutex;
122 
123 /*
124  * A mutex used to make the PSA global_data rng data thread safe.
125  *
126  * This mutex must be held when reading or writing to the PSA
127  * global_data rng_state or rng struct members. */
128 extern mbedtls_threading_mutex_t mbedtls_threading_psa_rngdata_mutex;
129 #endif
130 
131 #endif /* MBEDTLS_THREADING_C */
132 
133 #ifdef __cplusplus
134 }
135 #endif
136 
137 #endif /* threading.h */
138