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