1/*
2 * Copyright 2016 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#include <stdio.h>
11#include "internal/cryptlib.h"
12#include "internal/dso.h"
13#include "crypto/dso_conf.h"
14#include "internal/refcount.h"
15
16/**********************************************************************/
17/* The low-level handle type used to refer to a loaded shared library */
18
19struct dso_st {
20 DSO_METHOD *meth;
21 /*
22 * Standard dlopen uses a (void *). Win32 uses a HANDLE. VMS doesn't use
23 * anything but will need to cache the filename for use in the dso_bind
24 * handler. All in all, let each method control its own destiny.
25 * "Handles" and such go in a STACK.
26 */
27 STACK_OF(void) *meth_data;
28 CRYPTO_REF_COUNT references;
29 int flags;
30 /*
31 * For use by applications etc ... use this for your bits'n'pieces, don't
32 * touch meth_data!
33 */
34 CRYPTO_EX_DATA ex_data;
35 /*
36 * If this callback function pointer is set to non-NULL, then it will be
37 * used in DSO_load() in place of meth->dso_name_converter. NB: This
38 * should normally set using DSO_set_name_converter().
39 */
40 DSO_NAME_CONVERTER_FUNC name_converter;
41 /*
42 * If this callback function pointer is set to non-NULL, then it will be
43 * used in DSO_load() in place of meth->dso_merger. NB: This should
44 * normally set using DSO_set_merger().
45 */
46 DSO_MERGER_FUNC merger;
47 /*
48 * This is populated with (a copy of) the platform-independent filename
49 * used for this DSO.
50 */
51 char *filename;
52 /*
53 * This is populated with (a copy of) the translated filename by which
54 * the DSO was actually loaded. It is NULL iff the DSO is not currently
55 * loaded. NB: This is here because the filename translation process may
56 * involve a callback being invoked more than once not only to convert to
57 * a platform-specific form, but also to try different filenames in the
58 * process of trying to perform a load. As such, this variable can be
59 * used to indicate (a) whether this DSO structure corresponds to a
60 * loaded library or not, and (b) the filename with which it was actually
61 * loaded.
62 */
63 char *loaded_filename;
64 CRYPTO_RWLOCK *lock;
65};
66
67struct dso_meth_st {
68 const char *name;
69 /*
70 * Loads a shared library, NB: new DSO_METHODs must ensure that a
71 * successful load populates the loaded_filename field, and likewise a
72 * successful unload OPENSSL_frees and NULLs it out.
73 */
74 int (*dso_load) (DSO *dso);
75 /* Unloads a shared library */
76 int (*dso_unload) (DSO *dso);
77 /*
78 * Binds a function - assumes a return type of DSO_FUNC_TYPE. This should
79 * be cast to the real function prototype by the caller. Platforms that
80 * don't have compatible representations for different prototypes (this
81 * is possible within ANSI C) are highly unlikely to have shared
82 * libraries at all, let alone a DSO_METHOD implemented for them.
83 */
84 DSO_FUNC_TYPE (*dso_bind_func) (DSO *dso, const char *symname);
85 /*
86 * The generic (yuck) "ctrl()" function. NB: Negative return values
87 * (rather than zero) indicate errors.
88 */
89 long (*dso_ctrl) (DSO *dso, int cmd, long larg, void *parg);
90 /*
91 * The default DSO_METHOD-specific function for converting filenames to a
92 * canonical native form.
93 */
94 DSO_NAME_CONVERTER_FUNC dso_name_converter;
95 /*
96 * The default DSO_METHOD-specific function for converting filenames to a
97 * canonical native form.
98 */
99 DSO_MERGER_FUNC dso_merger;
100 /* [De]Initialisation handlers. */
101 int (*init) (DSO *dso);
102 int (*finish) (DSO *dso);
103 /* Return pathname of the module containing location */
104 int (*pathbyaddr) (void *addr, char *path, int sz);
105 /* Perform global symbol lookup, i.e. among *all* modules */
106 void *(*globallookup) (const char *symname);
107};
108