1/*
2 * Copyright 2000-2018 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#ifndef OSSL_INTERNAL_DSO_H
11# define OSSL_INTERNAL_DSO_H
12
13# include <openssl/crypto.h>
14# include "internal/dsoerr.h"
15
16/* These values are used as commands to DSO_ctrl() */
17# define DSO_CTRL_GET_FLAGS 1
18# define DSO_CTRL_SET_FLAGS 2
19# define DSO_CTRL_OR_FLAGS 3
20
21/*
22 * By default, DSO_load() will translate the provided filename into a form
23 * typical for the platform using the dso_name_converter function of the
24 * method. Eg. win32 will transform "blah" into "blah.dll", and dlfcn will
25 * transform it into "libblah.so". This callback could even utilise the
26 * DSO_METHOD's converter too if it only wants to override behaviour for
27 * one or two possible DSO methods. However, the following flag can be
28 * set in a DSO to prevent *any* native name-translation at all - eg. if
29 * the caller has prompted the user for a path to a driver library so the
30 * filename should be interpreted as-is.
31 */
32# define DSO_FLAG_NO_NAME_TRANSLATION 0x01
33/*
34 * An extra flag to give if only the extension should be added as
35 * translation. This is obviously only of importance on Unix and other
36 * operating systems where the translation also may prefix the name with
37 * something, like 'lib', and ignored everywhere else. This flag is also
38 * ignored if DSO_FLAG_NO_NAME_TRANSLATION is used at the same time.
39 */
40# define DSO_FLAG_NAME_TRANSLATION_EXT_ONLY 0x02
41
42/*
43 * Don't unload the DSO when we call DSO_free()
44 */
45# define DSO_FLAG_NO_UNLOAD_ON_FREE 0x04
46
47/*
48 * This flag loads the library with public symbols. Meaning: The exported
49 * symbols of this library are public to all libraries loaded after this
50 * library. At the moment only implemented in unix.
51 */
52# define DSO_FLAG_GLOBAL_SYMBOLS 0x20
53
54typedef void (*DSO_FUNC_TYPE) (void);
55
56typedef struct dso_st DSO;
57typedef struct dso_meth_st DSO_METHOD;
58
59/*
60 * The function prototype used for method functions (or caller-provided
61 * callbacks) that transform filenames. They are passed a DSO structure
62 * pointer (or NULL if they are to be used independently of a DSO object) and
63 * a filename to transform. They should either return NULL (if there is an
64 * error condition) or a newly allocated string containing the transformed
65 * form that the caller will need to free with OPENSSL_free() when done.
66 */
67typedef char *(*DSO_NAME_CONVERTER_FUNC)(DSO *, const char *);
68/*
69 * The function prototype used for method functions (or caller-provided
70 * callbacks) that merge two file specifications. They are passed a DSO
71 * structure pointer (or NULL if they are to be used independently of a DSO
72 * object) and two file specifications to merge. They should either return
73 * NULL (if there is an error condition) or a newly allocated string
74 * containing the result of merging that the caller will need to free with
75 * OPENSSL_free() when done. Here, merging means that bits and pieces are
76 * taken from each of the file specifications and added together in whatever
77 * fashion that is sensible for the DSO method in question. The only rule
78 * that really applies is that if the two specification contain pieces of the
79 * same type, the copy from the first string takes priority. One could see
80 * it as the first specification is the one given by the user and the second
81 * being a bunch of defaults to add on if they're missing in the first.
82 */
83typedef char *(*DSO_MERGER_FUNC)(DSO *, const char *, const char *);
84
85DSO *DSO_new(void);
86int DSO_free(DSO *dso);
87int DSO_flags(DSO *dso);
88int DSO_up_ref(DSO *dso);
89long DSO_ctrl(DSO *dso, int cmd, long larg, void *parg);
90
91/*
92 * These functions can be used to get/set the platform-independent filename
93 * used for a DSO. NB: set will fail if the DSO is already loaded.
94 */
95const char *DSO_get_filename(DSO *dso);
96int DSO_set_filename(DSO *dso, const char *filename);
97/*
98 * This function will invoke the DSO's name_converter callback to translate a
99 * filename, or if the callback isn't set it will instead use the DSO_METHOD's
100 * converter. If "filename" is NULL, the "filename" in the DSO itself will be
101 * used. If the DSO_FLAG_NO_NAME_TRANSLATION flag is set, then the filename is
102 * simply duplicated. NB: This function is usually called from within a
103 * DSO_METHOD during the processing of a DSO_load() call, and is exposed so
104 * that caller-created DSO_METHODs can do the same thing. A non-NULL return
105 * value will need to be OPENSSL_free()'d.
106 */
107char *DSO_convert_filename(DSO *dso, const char *filename);
108/*
109 * This function will invoke the DSO's merger callback to merge two file
110 * specifications, or if the callback isn't set it will instead use the
111 * DSO_METHOD's merger. A non-NULL return value will need to be
112 * OPENSSL_free()'d.
113 */
114char *DSO_merge(DSO *dso, const char *filespec1, const char *filespec2);
115
116/*
117 * The all-singing all-dancing load function, you normally pass NULL for the
118 * first and third parameters. Use DSO_up_ref and DSO_free for subsequent
119 * reference count handling. Any flags passed in will be set in the
120 * constructed DSO after its init() function but before the load operation.
121 * If 'dso' is non-NULL, 'flags' is ignored.
122 */
123DSO *DSO_load(DSO *dso, const char *filename, DSO_METHOD *meth, int flags);
124
125/* This function binds to a function inside a shared library. */
126DSO_FUNC_TYPE DSO_bind_func(DSO *dso, const char *symname);
127
128/*
129 * This method is the default, but will beg, borrow, or steal whatever method
130 * should be the default on any particular platform (including
131 * DSO_METH_null() if necessary).
132 */
133DSO_METHOD *DSO_METHOD_openssl(void);
134
135/*
136 * This function writes null-terminated pathname of DSO module containing
137 * 'addr' into 'sz' large caller-provided 'path' and returns the number of
138 * characters [including trailing zero] written to it. If 'sz' is 0 or
139 * negative, 'path' is ignored and required amount of characters [including
140 * trailing zero] to accommodate pathname is returned. If 'addr' is NULL, then
141 * pathname of cryptolib itself is returned. Negative or zero return value
142 * denotes error.
143 */
144int DSO_pathbyaddr(void *addr, char *path, int sz);
145
146/*
147 * Like DSO_pathbyaddr() but instead returns a handle to the DSO for the symbol
148 * or NULL on error.
149 */
150DSO *DSO_dsobyaddr(void *addr, int flags);
151
152/*
153 * This function should be used with caution! It looks up symbols in *all*
154 * loaded modules and if module gets unloaded by somebody else attempt to
155 * dereference the pointer is doomed to have fatal consequences. Primary
156 * usage for this function is to probe *core* system functionality, e.g.
157 * check if getnameinfo(3) is available at run-time without bothering about
158 * OS-specific details such as libc.so.versioning or where does it actually
159 * reside: in libc itself or libsocket.
160 */
161void *DSO_global_lookup(const char *name);
162
163int ERR_load_DSO_strings(void);
164
165#endif
166