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