1 WARNING WARNING WARNING!!! 2 3 This stuff is experimental, may change radically or be deleted altogether 4 before OpenSSL 0.9.7 release. You have been warned! 5 6 Configuration modules. These are a set of modules which can perform 7 various configuration functions. 8 9 Currently the routines should be called at most once when an application 10 starts up: that is before it starts any threads. 11 12 The routines read a configuration file set up like this: 13 14 ----- 15 #default section 16 openssl_init=init_section 17 18 [init_section] 19 20 module1=value1 21 #Second instance of module1 22 module1.1=valueX 23 module2=value2 24 module3=dso_literal 25 module4=dso_section 26 27 [dso_section] 28 29 path=/some/path/to/some/dso.so 30 other_stuff=other_value 31 ---- 32 33 When this file is loaded a configuration module with the specified 34 string (module* in the above example) is looked up and its init 35 function called as: 36 37 int conf_init_func(CONF_IMODULE *md, CONF *cnf); 38 39 The function can then take whatever action is appropriate, for example 40 further lookups based on the value. Multiple instances of the same 41 config module can be loaded. 42 43 When the application closes down the modules are cleaned up by calling 44 an optional finish function: 45 46 void conf_finish_func(CONF_IMODULE *md); 47 48 The finish functions are called in reverse order: that is the last module 49 loaded is the first one cleaned up. 50 51 If no module exists with a given name then an attempt is made to load 52 a DSO with the supplied name. This might mean that "module3" attempts 53 to load a DSO called libmodule3.so or module3.dll for example. An explicit 54 DSO name can be given by including a separate section as in the module4 example 55 above. 56 57 The DSO is expected to at least contain an initialization function: 58 59 int OPENSSL_init(CONF_IMODULE *md, CONF *cnf); 60 61 and may also include a finish function: 62 63 void OPENSSL_finish(CONF_IMODULE *md); 64 65 Static modules can also be added using, 66 67 int CONF_module_add(char *name, dso_mod_init_func *ifunc, dso_mod_finish_func *ffunc); 68 69 where "name" is the name in the configuration file this function corresponds to. 70 71 A set of builtin modules (currently only an ASN1 non functional test module) can be 72 added by calling OPENSSL_load_builtin_modules(). 73 74 The function OPENSSL_config() is intended as a simple configuration function that 75 any application can call to perform various default configuration tasks. It uses the 76 file openssl.cnf in the usual locations. 77 78 79
