crypto/openssl/include/internal/dso.h

   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