dso.h 7.0 KB

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  1. /*
  2. * Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
  3. *
  4. * Licensed under the OpenSSL license (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. #ifndef HEADER_DSO_H
  10. # define HEADER_DSO_H
  11. # include <openssl/crypto.h>
  12. # include "internal/dsoerr.h"
  13. #ifdef __cplusplus
  14. extern "C" {
  15. #endif
  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. * By default, DSO_load() will translate the provided filename into a form
  22. * typical for the platform using the dso_name_converter function of the
  23. * method. Eg. win32 will transform "blah" into "blah.dll", and dlfcn will
  24. * transform it into "libblah.so". This callback could even utilise the
  25. * DSO_METHOD's converter too if it only wants to override behaviour for
  26. * one or two possible DSO methods. However, the following flag can be
  27. * set in a DSO to prevent *any* native name-translation at all - eg. if
  28. * the caller has prompted the user for a path to a driver library so the
  29. * filename should be interpreted as-is.
  30. */
  31. # define DSO_FLAG_NO_NAME_TRANSLATION 0x01
  32. /*
  33. * An extra flag to give if only the extension should be added as
  34. * translation. This is obviously only of importance on Unix and other
  35. * operating systems where the translation also may prefix the name with
  36. * something, like 'lib', and ignored everywhere else. This flag is also
  37. * ignored if DSO_FLAG_NO_NAME_TRANSLATION is used at the same time.
  38. */
  39. # define DSO_FLAG_NAME_TRANSLATION_EXT_ONLY 0x02
  40. /*
  41. * Don't unload the DSO when we call DSO_free()
  42. */
  43. # define DSO_FLAG_NO_UNLOAD_ON_FREE 0x04
  44. /*
  45. * This flag loads the library with public symbols. Meaning: The exported
  46. * symbols of this library are public to all libraries loaded after this
  47. * library. At the moment only implemented in unix.
  48. */
  49. # define DSO_FLAG_GLOBAL_SYMBOLS 0x20
  50. typedef void (*DSO_FUNC_TYPE) (void);
  51. typedef struct dso_st DSO;
  52. typedef struct dso_meth_st DSO_METHOD;
  53. /*
  54. * The function prototype used for method functions (or caller-provided
  55. * callbacks) that transform filenames. They are passed a DSO structure
  56. * pointer (or NULL if they are to be used independently of a DSO object) and
  57. * a filename to transform. They should either return NULL (if there is an
  58. * error condition) or a newly allocated string containing the transformed
  59. * form that the caller will need to free with OPENSSL_free() when done.
  60. */
  61. typedef char *(*DSO_NAME_CONVERTER_FUNC)(DSO *, const char *);
  62. /*
  63. * The function prototype used for method functions (or caller-provided
  64. * callbacks) that merge two file specifications. They are passed a DSO
  65. * structure pointer (or NULL if they are to be used independently of a DSO
  66. * object) and two file specifications to merge. They should either return
  67. * NULL (if there is an error condition) or a newly allocated string
  68. * containing the result of merging that the caller will need to free with
  69. * OPENSSL_free() when done. Here, merging means that bits and pieces are
  70. * taken from each of the file specifications and added together in whatever
  71. * fashion that is sensible for the DSO method in question. The only rule
  72. * that really applies is that if the two specification contain pieces of the
  73. * same type, the copy from the first string takes priority. One could see
  74. * it as the first specification is the one given by the user and the second
  75. * being a bunch of defaults to add on if they're missing in the first.
  76. */
  77. typedef char *(*DSO_MERGER_FUNC)(DSO *, const char *, const char *);
  78. DSO *DSO_new(void);
  79. int DSO_free(DSO *dso);
  80. int DSO_flags(DSO *dso);
  81. int DSO_up_ref(DSO *dso);
  82. long DSO_ctrl(DSO *dso, int cmd, long larg, void *parg);
  83. /*
  84. * These functions can be used to get/set the platform-independent filename
  85. * used for a DSO. NB: set will fail if the DSO is already loaded.
  86. */
  87. const char *DSO_get_filename(DSO *dso);
  88. int DSO_set_filename(DSO *dso, const char *filename);
  89. /*
  90. * This function will invoke the DSO's name_converter callback to translate a
  91. * filename, or if the callback isn't set it will instead use the DSO_METHOD's
  92. * converter. If "filename" is NULL, the "filename" in the DSO itself will be
  93. * used. If the DSO_FLAG_NO_NAME_TRANSLATION flag is set, then the filename is
  94. * simply duplicated. NB: This function is usually called from within a
  95. * DSO_METHOD during the processing of a DSO_load() call, and is exposed so
  96. * that caller-created DSO_METHODs can do the same thing. A non-NULL return
  97. * value will need to be OPENSSL_free()'d.
  98. */
  99. char *DSO_convert_filename(DSO *dso, const char *filename);
  100. /*
  101. * This function will invoke the DSO's merger callback to merge two file
  102. * specifications, or if the callback isn't set it will instead use the
  103. * DSO_METHOD's merger. A non-NULL return value will need to be
  104. * OPENSSL_free()'d.
  105. */
  106. char *DSO_merge(DSO *dso, const char *filespec1, const char *filespec2);
  107. /*
  108. * The all-singing all-dancing load function, you normally pass NULL for the
  109. * first and third parameters. Use DSO_up_ref and DSO_free for subsequent
  110. * reference count handling. Any flags passed in will be set in the
  111. * constructed DSO after its init() function but before the load operation.
  112. * If 'dso' is non-NULL, 'flags' is ignored.
  113. */
  114. DSO *DSO_load(DSO *dso, const char *filename, DSO_METHOD *meth, int flags);
  115. /* This function binds to a function inside a shared library. */
  116. DSO_FUNC_TYPE DSO_bind_func(DSO *dso, const char *symname);
  117. /*
  118. * This method is the default, but will beg, borrow, or steal whatever method
  119. * should be the default on any particular platform (including
  120. * DSO_METH_null() if necessary).
  121. */
  122. DSO_METHOD *DSO_METHOD_openssl(void);
  123. /*
  124. * This function writes null-terminated pathname of DSO module containing
  125. * 'addr' into 'sz' large caller-provided 'path' and returns the number of
  126. * characters [including trailing zero] written to it. If 'sz' is 0 or
  127. * negative, 'path' is ignored and required amount of characters [including
  128. * trailing zero] to accommodate pathname is returned. If 'addr' is NULL, then
  129. * pathname of cryptolib itself is returned. Negative or zero return value
  130. * denotes error.
  131. */
  132. int DSO_pathbyaddr(void *addr, char *path, int sz);
  133. /*
  134. * Like DSO_pathbyaddr() but instead returns a handle to the DSO for the symbol
  135. * or NULL on error.
  136. */
  137. DSO *DSO_dsobyaddr(void *addr, int flags);
  138. /*
  139. * This function should be used with caution! It looks up symbols in *all*
  140. * loaded modules and if module gets unloaded by somebody else attempt to
  141. * dereference the pointer is doomed to have fatal consequences. Primary
  142. * usage for this function is to probe *core* system functionality, e.g.
  143. * check if getnameinfo(3) is available at run-time without bothering about
  144. * OS-specific details such as libc.so.versioning or where does it actually
  145. * reside: in libc itself or libsocket.
  146. */
  147. void *DSO_global_lookup(const char *name);
  148. int ERR_load_DSO_strings(void);
  149. # ifdef __cplusplus
  150. }
  151. # endif
  152. #endif