1 /* 2 * Copyright 2000-2021 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 # pragma once 13 14 # include <openssl/crypto.h> 15 # include "internal/dsoerr.h" 16 17 /* These values are used as commands to DSO_ctrl() */ 18 # define DSO_CTRL_GET_FLAGS 1 19 # define DSO_CTRL_SET_FLAGS 2 20 # define DSO_CTRL_OR_FLAGS 3 21 22 /* 23 * By default, DSO_load() will translate the provided filename into a form 24 * typical for the platform using the dso_name_converter function of the 25 * method. Eg. win32 will transform "blah" into "blah.dll", and dlfcn will 26 * transform it into "libblah.so". This callback could even utilise the 27 * DSO_METHOD's converter too if it only wants to override behaviour for 28 * one or two possible DSO methods. However, the following flag can be 29 * set in a DSO to prevent *any* native name-translation at all - eg. if 30 * the caller has prompted the user for a path to a driver library so the 31 * filename should be interpreted as-is. 32 */ 33 # define DSO_FLAG_NO_NAME_TRANSLATION 0x01 34 /* 35 * An extra flag to give if only the extension should be added as 36 * translation. This is obviously only of importance on Unix and other 37 * operating systems where the translation also may prefix the name with 38 * something, like 'lib', and ignored everywhere else. This flag is also 39 * ignored if DSO_FLAG_NO_NAME_TRANSLATION is used at the same time. 40 */ 41 # define DSO_FLAG_NAME_TRANSLATION_EXT_ONLY 0x02 42 43 /* 44 * Don't unload the DSO when we call DSO_free() 45 */ 46 # define DSO_FLAG_NO_UNLOAD_ON_FREE 0x04 47 48 /* 49 * This flag loads the library with public symbols. Meaning: The exported 50 * symbols of this library are public to all libraries loaded after this 51 * library. At the moment only implemented in unix. 52 */ 53 # define DSO_FLAG_GLOBAL_SYMBOLS 0x20 54 55 typedef void (*DSO_FUNC_TYPE) (void); 56 57 typedef struct dso_st DSO; 58 typedef struct dso_meth_st DSO_METHOD; 59 60 /* 61 * The function prototype used for method functions (or caller-provided 62 * callbacks) that transform filenames. They are passed a DSO structure 63 * pointer (or NULL if they are to be used independently of a DSO object) and 64 * a filename to transform. They should either return NULL (if there is an 65 * error condition) or a newly allocated string containing the transformed 66 * form that the caller will need to free with OPENSSL_free() when done. 67 */ 68 typedef char *(*DSO_NAME_CONVERTER_FUNC)(DSO *, const char *); 69 /* 70 * The function prototype used for method functions (or caller-provided 71 * callbacks) that merge two file specifications. They are passed a DSO 72 * structure pointer (or NULL if they are to be used independently of a DSO 73 * object) and two file specifications to merge. They should either return 74 * NULL (if there is an error condition) or a newly allocated string 75 * containing the result of merging that the caller will need to free with 76 * OPENSSL_free() when done. Here, merging means that bits and pieces are 77 * taken from each of the file specifications and added together in whatever 78 * fashion that is sensible for the DSO method in question. The only rule 79 * that really applies is that if the two specification contain pieces of the 80 * same type, the copy from the first string takes priority. One could see 81 * it as the first specification is the one given by the user and the second 82 * being a bunch of defaults to add on if they're missing in the first. 83 */ 84 typedef char *(*DSO_MERGER_FUNC)(DSO *, const char *, const char *); 85 86 DSO *DSO_new(void); 87 int DSO_free(DSO *dso); 88 int DSO_flags(DSO *dso); 89 int DSO_up_ref(DSO *dso); 90 long DSO_ctrl(DSO *dso, int cmd, long larg, void *parg); 91 92 /* 93 * These functions can be used to get/set the platform-independent filename 94 * used for a DSO. NB: set will fail if the DSO is already loaded. 95 */ 96 const char *DSO_get_filename(DSO *dso); 97 int DSO_set_filename(DSO *dso, const char *filename); 98 /* 99 * This function will invoke the DSO's name_converter callback to translate a 100 * filename, or if the callback isn't set it will instead use the DSO_METHOD's 101 * converter. If "filename" is NULL, the "filename" in the DSO itself will be 102 * used. If the DSO_FLAG_NO_NAME_TRANSLATION flag is set, then the filename is 103 * simply duplicated. NB: This function is usually called from within a 104 * DSO_METHOD during the processing of a DSO_load() call, and is exposed so 105 * that caller-created DSO_METHODs can do the same thing. A non-NULL return 106 * value will need to be OPENSSL_free()'d. 107 */ 108 char *DSO_convert_filename(DSO *dso, const char *filename); 109 /* 110 * This function will invoke the DSO's merger callback to merge two file 111 * specifications, or if the callback isn't set it will instead use the 112 * DSO_METHOD's merger. A non-NULL return value will need to be 113 * OPENSSL_free()'d. 114 */ 115 char *DSO_merge(DSO *dso, const char *filespec1, const char *filespec2); 116 117 /* 118 * The all-singing all-dancing load function, you normally pass NULL for the 119 * first and third parameters. Use DSO_up_ref and DSO_free for subsequent 120 * reference count handling. Any flags passed in will be set in the 121 * constructed DSO after its init() function but before the load operation. 122 * If 'dso' is non-NULL, 'flags' is ignored. 123 */ 124 DSO *DSO_load(DSO *dso, const char *filename, DSO_METHOD *meth, int flags); 125 126 /* This function binds to a function inside a shared library. */ 127 DSO_FUNC_TYPE DSO_bind_func(DSO *dso, const char *symname); 128 129 /* 130 * This method is the default, but will beg, borrow, or steal whatever method 131 * should be the default on any particular platform (including 132 * DSO_METH_null() if necessary). 133 */ 134 DSO_METHOD *DSO_METHOD_openssl(void); 135 136 /* 137 * This function writes null-terminated pathname of DSO module containing 138 * 'addr' into 'sz' large caller-provided 'path' and returns the number of 139 * characters [including trailing zero] written to it. If 'sz' is 0 or 140 * negative, 'path' is ignored and required amount of characters [including 141 * trailing zero] to accommodate pathname is returned. If 'addr' is NULL, then 142 * pathname of cryptolib itself is returned. Negative or zero return value 143 * denotes error. 144 */ 145 int DSO_pathbyaddr(void *addr, char *path, int sz); 146 147 /* 148 * Like DSO_pathbyaddr() but instead returns a handle to the DSO for the symbol 149 * or NULL on error. 150 */ 151 DSO *DSO_dsobyaddr(void *addr, int flags); 152 153 /* 154 * This function should be used with caution! It looks up symbols in *all* 155 * loaded modules and if module gets unloaded by somebody else attempt to 156 * dereference the pointer is doomed to have fatal consequences. Primary 157 * usage for this function is to probe *core* system functionality, e.g. 158 * check if getnameinfo(3) is available at run-time without bothering about 159 * OS-specific details such as libc.so.versioning or where does it actually 160 * reside: in libc itself or libsocket. 161 */ 162 void *DSO_global_lookup(const char *name); 163 164 #endif 165