crypto/async/arch/async_posix.c

   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
  27 int async_local_init(void)
  28 {
  29     async_mem_lock = CRYPTO_THREAD_lock_new();
  30     return async_mem_lock != NULL;
  31 }
  32
  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
  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
  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
  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
  82 static void *async_stack_alloc(size_t *num)
  83 {
  84     return OPENSSL_malloc(*num);
  85 }
  86
  87 static void async_stack_free(void *addr)
  88 {
  89     OPENSSL_free(addr);
  90 }
  91
  92 void async_local_cleanup(void)
  93 {
  94 }
  95
  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
 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