xref: /openssl/crypto/async/arch/async_posix.c (revision e077455e) 
1 /*
2  * Copyright 2015-2022 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the Apache License 2.0 (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9 
10 /* This must be the first #include file */
11 #include "../async_local.h"
12 
13 #ifdef ASYNC_POSIX
14 
15 # include <stddef.h>
16 # include <unistd.h>
17 # include <openssl/err.h>
18 # include <openssl/crypto.h>
19 
20 #define STACKSIZE       32768
21 
22 static CRYPTO_RWLOCK *async_mem_lock;
23 
24 static void *async_stack_alloc(size_t *num);
25 static void async_stack_free(void *addr);
26 
async_local_init(void)27 int async_local_init(void)
28 {
29     async_mem_lock = CRYPTO_THREAD_lock_new();
30     return async_mem_lock != NULL;
31 }
32 
async_local_deinit(void)33 void async_local_deinit(void)
34 {
35     CRYPTO_THREAD_lock_free(async_mem_lock);
36 }
37 
38 static int allow_customize = 1;
39 static ASYNC_stack_alloc_fn stack_alloc_impl = async_stack_alloc;
40 static ASYNC_stack_free_fn stack_free_impl = async_stack_free;
41 
ASYNC_is_capable(void)42 int ASYNC_is_capable(void)
43 {
44     ucontext_t ctx;
45 
46     /*
47      * Some platforms provide getcontext() but it does not work (notably
48      * MacOSX PPC64). Check for a working getcontext();
49      */
50     return getcontext(&ctx) == 0;
51 }
52 
ASYNC_set_mem_functions(ASYNC_stack_alloc_fn alloc_fn,ASYNC_stack_free_fn free_fn)53 int ASYNC_set_mem_functions(ASYNC_stack_alloc_fn alloc_fn,
54                             ASYNC_stack_free_fn free_fn)
55 {
56     OPENSSL_init_crypto(OPENSSL_INIT_ASYNC, NULL);
57 
58     if (!CRYPTO_THREAD_write_lock(async_mem_lock))
59         return 0;
60     if (!allow_customize) {
61         CRYPTO_THREAD_unlock(async_mem_lock);
62         return 0;
63     }
64     CRYPTO_THREAD_unlock(async_mem_lock);
65 
66     if (alloc_fn != NULL)
67         stack_alloc_impl = alloc_fn;
68     if (free_fn != NULL)
69         stack_free_impl = free_fn;
70     return 1;
71 }
72 
ASYNC_get_mem_functions(ASYNC_stack_alloc_fn * alloc_fn,ASYNC_stack_free_fn * free_fn)73 void ASYNC_get_mem_functions(ASYNC_stack_alloc_fn *alloc_fn,
74                              ASYNC_stack_free_fn *free_fn)
75 {
76     if (alloc_fn != NULL)
77         *alloc_fn = stack_alloc_impl;
78     if (free_fn != NULL)
79         *free_fn = stack_free_impl;
80 }
81 
async_stack_alloc(size_t * num)82 static void *async_stack_alloc(size_t *num)
83 {
84     return OPENSSL_malloc(*num);
85 }
86 
async_stack_free(void * addr)87 static void async_stack_free(void *addr)
88 {
89     OPENSSL_free(addr);
90 }
91 
async_local_cleanup(void)92 void async_local_cleanup(void)
93 {
94 }
95 
async_fibre_makecontext(async_fibre * fibre)96 int async_fibre_makecontext(async_fibre *fibre)
97 {
98 #ifndef USE_SWAPCONTEXT
99     fibre->env_init = 0;
100 #endif
101     if (getcontext(&fibre->fibre) == 0) {
102         size_t num = STACKSIZE;
103 
104         /*
105          *  Disallow customisation after the first
106          *  stack is allocated.
107          */
108         if (allow_customize) {
109             if (!CRYPTO_THREAD_write_lock(async_mem_lock))
110                 return 0;
111             allow_customize = 0;
112             CRYPTO_THREAD_unlock(async_mem_lock);
113         }
114 
115         fibre->fibre.uc_stack.ss_sp = stack_alloc_impl(&num);
116         if (fibre->fibre.uc_stack.ss_sp != NULL) {
117             fibre->fibre.uc_stack.ss_size = num;
118             fibre->fibre.uc_link = NULL;
119             makecontext(&fibre->fibre, async_start_func, 0);
120             return 1;
121         }
122     } else {
123         fibre->fibre.uc_stack.ss_sp = NULL;
124     }
125     return 0;
126 }
127 
async_fibre_free(async_fibre * fibre)128 void async_fibre_free(async_fibre *fibre)
129 {
130     stack_free_impl(fibre->fibre.uc_stack.ss_sp);
131     fibre->fibre.uc_stack.ss_sp = NULL;
132 }
133 
134 #endif
135