1=pod 2 3=head1 NAME 4 5OPENSSL_INIT_new, OPENSSL_INIT_set_config_appname, OPENSSL_INIT_free, 6OPENSSL_init_crypto, OPENSSL_cleanup, 7OPENSSL_atexit, OPENSSL_thread_stop - OpenSSL 8initialisation and deinitialisation functions 9 10=head1 SYNOPSIS 11 12 #include <openssl/crypto.h> 13 14 void OPENSSL_cleanup(void); 15 int OPENSSL_init_crypto(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings); 16 int OPENSSL_atexit(void (*handler)(void)); 17 void OPENSSL_thread_stop(void); 18 19 OPENSSL_INIT_SETTINGS *OPENSSL_INIT_new(void); 20 int OPENSSL_INIT_set_config_appname(OPENSSL_INIT_SETTINGS *init, 21 const char* name); 22 void OPENSSL_INIT_free(OPENSSL_INIT_SETTINGS *init); 23 24=head1 DESCRIPTION 25 26During normal operation OpenSSL (libcrypto) will allocate various resources at 27start up that must, subsequently, be freed on close down of the library. 28Additionally some resources are allocated on a per thread basis (if the 29application is multi-threaded), and these resources must be freed prior to the 30thread closing. 31 32As of version 1.1.0 OpenSSL will automatically allocate all resources that it 33needs so no explicit initialisation is required. Similarly it will also 34automatically deinitialise as required. 35 36However, there way be situations when explicit initialisation is desirable or 37needed, for example when some non-default initialisation is required. The 38function OPENSSL_init_crypto() can be used for this purpose for 39libcrypto (see also L<OPENSSL_init_ssl(3)> for the libssl 40equivalent). 41 42Numerous internal OpenSSL functions call OPENSSL_init_crypto(). 43Therefore, in order to perform non-default initialisation, 44OPENSSL_init_crypto() MUST be called by application code prior to 45any other OpenSSL function calls. 46 47The B<opts> parameter specifies which aspects of libcrypto should be 48initialised. Valid options are: 49 50=over 4 51 52=item OPENSSL_INIT_NO_LOAD_CRYPTO_STRINGS 53 54Suppress automatic loading of the libcrypto error strings. This option is 55not a default option. Once selected subsequent calls to 56OPENSSL_init_crypto() with the option 57B<OPENSSL_INIT_LOAD_CRYPTO_STRINGS> will be ignored. 58 59=item OPENSSL_INIT_LOAD_CRYPTO_STRINGS 60 61Automatic loading of the libcrypto error strings. With this option the 62library will automatically load the libcrypto error strings. 63This option is a default option. Once selected subsequent calls to 64OPENSSL_init_crypto() with the option 65B<OPENSSL_INIT_NO_LOAD_CRYPTO_STRINGS> will be ignored. 66 67=item OPENSSL_INIT_ADD_ALL_CIPHERS 68 69With this option the library will automatically load and make available all 70libcrypto ciphers. This option is a default option. Once selected subsequent 71calls to OPENSSL_init_crypto() with the option 72B<OPENSSL_INIT_NO_ADD_ALL_CIPHERS> will be ignored. 73 74=item OPENSSL_INIT_ADD_ALL_DIGESTS 75 76With this option the library will automatically load and make available all 77libcrypto digests. This option is a default option. Once selected subsequent 78calls to OPENSSL_init_crypto() with the option 79B<OPENSSL_INIT_NO_ADD_ALL_CIPHERS> will be ignored. 80 81=item OPENSSL_INIT_NO_ADD_ALL_CIPHERS 82 83With this option the library will suppress automatic loading of libcrypto 84ciphers. This option is not a default option. Once selected subsequent 85calls to OPENSSL_init_crypto() with the option 86B<OPENSSL_INIT_ADD_ALL_CIPHERS> will be ignored. 87 88=item OPENSSL_INIT_NO_ADD_ALL_DIGESTS 89 90With this option the library will suppress automatic loading of libcrypto 91digests. This option is not a default option. Once selected subsequent 92calls to OPENSSL_init_crypto() with the option 93B<OPENSSL_INIT_ADD_ALL_DIGESTS> will be ignored. 94 95=item OPENSSL_INIT_LOAD_CONFIG 96 97With this option an OpenSSL configuration file will be automatically loaded and 98used by calling OPENSSL_config(). This is not a default option for libcrypto. 99From OpenSSL 1.1.1 this is a default option for libssl (see 100L<OPENSSL_init_ssl(3)> for further details about libssl initialisation). See the 101description of OPENSSL_INIT_new(), below. 102 103=item OPENSSL_INIT_NO_LOAD_CONFIG 104 105With this option the loading of OpenSSL configuration files will be suppressed. 106It is the equivalent of calling OPENSSL_no_config(). This is not a default 107option. 108 109=item OPENSSL_INIT_ASYNC 110 111With this option the library with automatically initialise the libcrypto async 112sub-library (see L<ASYNC_start_job(3)>). This is a default option. 113 114=item OPENSSL_INIT_ENGINE_RDRAND 115 116With this option the library will automatically load and initialise the 117RDRAND engine (if available). This not a default option. 118 119=item OPENSSL_INIT_ENGINE_DYNAMIC 120 121With this option the library will automatically load and initialise the 122dynamic engine. This not a default option. 123 124=item OPENSSL_INIT_ENGINE_OPENSSL 125 126With this option the library will automatically load and initialise the 127openssl engine. This not a default option. 128 129=item OPENSSL_INIT_ENGINE_CRYPTODEV 130 131With this option the library will automatically load and initialise the 132cryptodev engine (if available). This not a default option. 133 134=item OPENSSL_INIT_ENGINE_CAPI 135 136With this option the library will automatically load and initialise the 137CAPI engine (if available). This not a default option. 138 139=item OPENSSL_INIT_ENGINE_PADLOCK 140 141With this option the library will automatically load and initialise the 142padlock engine (if available). This not a default option. 143 144=item OPENSSL_INIT_ENGINE_AFALG 145 146With this option the library will automatically load and initialise the 147AFALG engine. This not a default option. 148 149=item OPENSSL_INIT_ENGINE_ALL_BUILTIN 150 151With this option the library will automatically load and initialise all the 152built in engines listed above with the exception of the openssl and afalg 153engines. This not a default option. 154 155=item OPENSSL_INIT_ATFORK 156 157With this option the library will register its fork handlers. 158See OPENSSL_fork_prepare(3) for details. 159 160=back 161 162Multiple options may be combined together in a single call to 163OPENSSL_init_crypto(). For example: 164 165 OPENSSL_init_crypto(OPENSSL_INIT_NO_ADD_ALL_CIPHERS 166 | OPENSSL_INIT_NO_ADD_ALL_DIGESTS, NULL); 167 168The OPENSSL_cleanup() function deinitialises OpenSSL (both libcrypto 169and libssl). All resources allocated by OpenSSL are freed. Typically there 170should be no need to call this function directly as it is initiated 171automatically on application exit. This is done via the standard C library 172atexit() function. In the event that the application will close in a manner 173that will not call the registered atexit() handlers then the application should 174call OPENSSL_cleanup() directly. Developers of libraries using OpenSSL 175are discouraged from calling this function and should instead, typically, rely 176on auto-deinitialisation. This is to avoid error conditions where both an 177application and a library it depends on both use OpenSSL, and the library 178deinitialises it before the application has finished using it. 179 180Once OPENSSL_cleanup() has been called the library cannot be reinitialised. 181Attempts to call OPENSSL_init_crypto() will fail and an ERR_R_INIT_FAIL error 182will be added to the error stack. Note that because initialisation has failed 183OpenSSL error strings will not be available, only an error code. This code can 184be put through the openssl errstr command line application to produce a human 185readable error (see L<errstr(1)>). 186 187The OPENSSL_atexit() function enables the registration of a 188function to be called during OPENSSL_cleanup(). Stop handlers are 189called after deinitialisation of resources local to a thread, but before other 190process wide resources are freed. In the event that multiple stop handlers are 191registered, no guarantees are made about the order of execution. 192 193The OPENSSL_thread_stop() function deallocates resources associated 194with the current thread. Typically this function will be called automatically by 195the library when the thread exits. This should only be called directly if 196resources should be freed at an earlier time, or under the circumstances 197described in the NOTES section below. 198 199The B<OPENSSL_INIT_LOAD_CONFIG> flag will load a default configuration 200file. For optional configuration file settings, an B<OPENSSL_INIT_SETTINGS> 201must be created and used. 202The routines OPENSSL_init_new() and OPENSSL_INIT_set_config_appname() can 203be used to allocate the object and set the application name, and then the 204object can be released with OPENSSL_INIT_free() when done. 205 206=head1 NOTES 207 208Resources local to a thread are deallocated automatically when the thread exits 209(e.g. in a pthreads environment, when pthread_exit() is called). On Windows 210platforms this is done in response to a DLL_THREAD_DETACH message being sent to 211the libcrypto32.dll entry point. Some windows functions may cause threads to exit 212without sending this message (for example ExitProcess()). If the application 213uses such functions, then the application must free up OpenSSL resources 214directly via a call to OPENSSL_thread_stop() on each thread. Similarly this 215message will also not be sent if OpenSSL is linked statically, and therefore 216applications using static linking should also call OPENSSL_thread_stop() on each 217thread. Additionally if OpenSSL is loaded dynamically via LoadLibrary() and the 218threads are not destroyed until after FreeLibrary() is called then each thread 219should call OPENSSL_thread_stop() prior to the FreeLibrary() call. 220 221On Linux/Unix where OpenSSL has been loaded via dlopen() and the application is 222multi-threaded and if dlclose() is subsequently called prior to the threads 223being destroyed then OpenSSL will not be able to deallocate resources associated 224with those threads. The application should either call OPENSSL_thread_stop() on 225each thread prior to the dlclose() call, or alternatively the original dlopen() 226call should use the RTLD_NODELETE flag (where available on the platform). 227 228=head1 RETURN VALUES 229 230The functions OPENSSL_init_crypto, OPENSSL_atexit() and 231OPENSSL_INIT_set_config_appname() return 1 on success or 0 on error. 232 233=head1 SEE ALSO 234 235L<OPENSSL_init_ssl(3)> 236 237=head1 HISTORY 238 239The OPENSSL_init_crypto(), OPENSSL_cleanup(), OPENSSL_atexit(), 240OPENSSL_thread_stop(), OPENSSL_INIT_new(), OPENSSL_INIT_set_config_appname() 241and OPENSSL_INIT_free() functions were added in OpenSSL 1.1.0. 242 243=head1 COPYRIGHT 244 245Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved. 246 247Licensed under the OpenSSL license (the "License"). You may not use 248this file except in compliance with the License. You can obtain a copy 249in the file LICENSE in the source distribution or at 250L<https://www.openssl.org/source/license.html>. 251 252=cut 253