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dso.h
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1 /* dso.h -*- mode:C; c-file-style: "eay" -*- */
2 /* Written by Geoff Thorpe ([email protected]) for the OpenSSL
3  * project 2000.
4  */
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58 
59 #ifndef HEADER_DSO_H
60 #define HEADER_DSO_H
61 
62 #include <openssl/crypto.h>
63 
64 #ifdef __cplusplus
65 extern "C" {
66 #endif
67 
68 /* These values are used as commands to DSO_ctrl() */
69 #define DSO_CTRL_GET_FLAGS 1
70 #define DSO_CTRL_SET_FLAGS 2
71 #define DSO_CTRL_OR_FLAGS 3
72 
73 /* By default, DSO_load() will translate the provided filename into a form
74  * typical for the platform (more specifically the DSO_METHOD) using the
75  * dso_name_converter function of the method. Eg. win32 will transform "blah"
76  * into "blah.dll", and dlfcn will transform it into "libblah.so". The
77  * behaviour can be overriden by setting the name_converter callback in the DSO
78  * object (using DSO_set_name_converter()). This callback could even utilise
79  * the DSO_METHOD's converter too if it only wants to override behaviour for
80  * one or two possible DSO methods. However, the following flag can be set in a
81  * DSO to prevent *any* native name-translation at all - eg. if the caller has
82  * prompted the user for a path to a driver library so the filename should be
83  * interpreted as-is. */
84 #define DSO_FLAG_NO_NAME_TRANSLATION 0x01
85 /* An extra flag to give if only the extension should be added as
86  * translation. This is obviously only of importance on Unix and
87  * other operating systems where the translation also may prefix
88  * the name with something, like 'lib', and ignored everywhere else.
89  * This flag is also ignored if DSO_FLAG_NO_NAME_TRANSLATION is used
90  * at the same time. */
91 #define DSO_FLAG_NAME_TRANSLATION_EXT_ONLY 0x02
92 
93 /* The following flag controls the translation of symbol names to upper
94  * case. This is currently only being implemented for OpenVMS.
95  */
96 #define DSO_FLAG_UPCASE_SYMBOL 0x10
97 
98 /* This flag loads the library with public symbols.
99  * Meaning: The exported symbols of this library are public
100  * to all libraries loaded after this library.
101  * At the moment only implemented in unix.
102  */
103 #define DSO_FLAG_GLOBAL_SYMBOLS 0x20
104 
105 
106 typedef void (*DSO_FUNC_TYPE)(void);
107 
108 typedef struct dso_st DSO;
109 
110 /* The function prototype used for method functions (or caller-provided
111  * callbacks) that transform filenames. They are passed a DSO structure pointer
112  * (or NULL if they are to be used independantly of a DSO object) and a
113  * filename to transform. They should either return NULL (if there is an error
114  * condition) or a newly allocated string containing the transformed form that
115  * the caller will need to free with OPENSSL_free() when done. */
116 typedef char* (*DSO_NAME_CONVERTER_FUNC)(DSO *, const char *);
117 /* The function prototype used for method functions (or caller-provided
118  * callbacks) that merge two file specifications. They are passed a
119  * DSO structure pointer (or NULL if they are to be used independantly of
120  * a DSO object) and two file specifications to merge. They should
121  * either return NULL (if there is an error condition) or a newly allocated
122  * string containing the result of merging that the caller will need
123  * to free with OPENSSL_free() when done.
124  * Here, merging means that bits and pieces are taken from each of the
125  * file specifications and added together in whatever fashion that is
126  * sensible for the DSO method in question. The only rule that really
127  * applies is that if the two specification contain pieces of the same
128  * type, the copy from the first string takes priority. One could see
129  * it as the first specification is the one given by the user and the
130  * second being a bunch of defaults to add on if they're missing in the
131  * first. */
132 typedef char* (*DSO_MERGER_FUNC)(DSO *, const char *, const char *);
133 
134 typedef struct dso_meth_st
135  {
136  const char *name;
137  /* Loads a shared library, NB: new DSO_METHODs must ensure that a
138  * successful load populates the loaded_filename field, and likewise a
139  * successful unload OPENSSL_frees and NULLs it out. */
140  int (*dso_load)(DSO *dso);
141  /* Unloads a shared library */
142  int (*dso_unload)(DSO *dso);
143  /* Binds a variable */
144  void *(*dso_bind_var)(DSO *dso, const char *symname);
145  /* Binds a function - assumes a return type of DSO_FUNC_TYPE.
146  * This should be cast to the real function prototype by the
147  * caller. Platforms that don't have compatible representations
148  * for different prototypes (this is possible within ANSI C)
149  * are highly unlikely to have shared libraries at all, let
150  * alone a DSO_METHOD implemented for them. */
151  DSO_FUNC_TYPE (*dso_bind_func)(DSO *dso, const char *symname);
152 
153 /* I don't think this would actually be used in any circumstances. */
154 #if 0
155  /* Unbinds a variable */
156  int (*dso_unbind_var)(DSO *dso, char *symname, void *symptr);
157  /* Unbinds a function */
158  int (*dso_unbind_func)(DSO *dso, char *symname, DSO_FUNC_TYPE symptr);
159 #endif
160  /* The generic (yuck) "ctrl()" function. NB: Negative return
161  * values (rather than zero) indicate errors. */
162  long (*dso_ctrl)(DSO *dso, int cmd, long larg, void *parg);
163  /* The default DSO_METHOD-specific function for converting filenames to
164  * a canonical native form. */
166  /* The default DSO_METHOD-specific function for converting filenames to
167  * a canonical native form. */
169 
170  /* [De]Initialisation handlers. */
171  int (*init)(DSO *dso);
172  int (*finish)(DSO *dso);
173 
174  /* Return pathname of the module containing location */
175  int (*pathbyaddr)(void *addr,char *path,int sz);
176  /* Perform global symbol lookup, i.e. among *all* modules */
177  void *(*globallookup)(const char *symname);
178  } DSO_METHOD;
179 
180 /**********************************************************************/
181 /* The low-level handle type used to refer to a loaded shared library */
182 
183 struct dso_st
184  {
186  /* Standard dlopen uses a (void *). Win32 uses a HANDLE. VMS
187  * doesn't use anything but will need to cache the filename
188  * for use in the dso_bind handler. All in all, let each
189  * method control its own destiny. "Handles" and such go in
190  * a STACK. */
191  STACK_OF(void) *meth_data;
193  int flags;
194  /* For use by applications etc ... use this for your bits'n'pieces,
195  * don't touch meth_data! */
197  /* If this callback function pointer is set to non-NULL, then it will
198  * be used in DSO_load() in place of meth->dso_name_converter. NB: This
199  * should normally set using DSO_set_name_converter(). */
201  /* If this callback function pointer is set to non-NULL, then it will
202  * be used in DSO_load() in place of meth->dso_merger. NB: This
203  * should normally set using DSO_set_merger(). */
205  /* This is populated with (a copy of) the platform-independant
206  * filename used for this DSO. */
207  char *filename;
208  /* This is populated with (a copy of) the translated filename by which
209  * the DSO was actually loaded. It is NULL iff the DSO is not currently
210  * loaded. NB: This is here because the filename translation process
211  * may involve a callback being invoked more than once not only to
212  * convert to a platform-specific form, but also to try different
213  * filenames in the process of trying to perform a load. As such, this
214  * variable can be used to indicate (a) whether this DSO structure
215  * corresponds to a loaded library or not, and (b) the filename with
216  * which it was actually loaded. */
218  };
219 
220 
221 DSO * DSO_new(void);
222 DSO * DSO_new_method(DSO_METHOD *method);
223 int DSO_free(DSO *dso);
224 int DSO_flags(DSO *dso);
225 int DSO_up_ref(DSO *dso);
226 long DSO_ctrl(DSO *dso, int cmd, long larg, void *parg);
227 
228 /* This function sets the DSO's name_converter callback. If it is non-NULL,
229  * then it will be used instead of the associated DSO_METHOD's function. If
230  * oldcb is non-NULL then it is set to the function pointer value being
231  * replaced. Return value is non-zero for success. */
233  DSO_NAME_CONVERTER_FUNC *oldcb);
234 /* These functions can be used to get/set the platform-independant filename
235  * used for a DSO. NB: set will fail if the DSO is already loaded. */
236 const char *DSO_get_filename(DSO *dso);
237 int DSO_set_filename(DSO *dso, const char *filename);
238 /* This function will invoke the DSO's name_converter callback to translate a
239  * filename, or if the callback isn't set it will instead use the DSO_METHOD's
240  * converter. If "filename" is NULL, the "filename" in the DSO itself will be
241  * used. If the DSO_FLAG_NO_NAME_TRANSLATION flag is set, then the filename is
242  * simply duplicated. NB: This function is usually called from within a
243  * DSO_METHOD during the processing of a DSO_load() call, and is exposed so that
244  * caller-created DSO_METHODs can do the same thing. A non-NULL return value
245  * will need to be OPENSSL_free()'d. */
246 char *DSO_convert_filename(DSO *dso, const char *filename);
247 /* This function will invoke the DSO's merger callback to merge two file
248  * specifications, or if the callback isn't set it will instead use the
249  * DSO_METHOD's merger. A non-NULL return value will need to be
250  * OPENSSL_free()'d. */
251 char *DSO_merge(DSO *dso, const char *filespec1, const char *filespec2);
252 /* If the DSO is currently loaded, this returns the filename that it was loaded
253  * under, otherwise it returns NULL. So it is also useful as a test as to
254  * whether the DSO is currently loaded. NB: This will not necessarily return
255  * the same value as DSO_convert_filename(dso, dso->filename), because the
256  * DSO_METHOD's load function may have tried a variety of filenames (with
257  * and/or without the aid of the converters) before settling on the one it
258  * actually loaded. */
259 const char *DSO_get_loaded_filename(DSO *dso);
260 
263 DSO_METHOD *DSO_get_method(DSO *dso);
264 DSO_METHOD *DSO_set_method(DSO *dso, DSO_METHOD *meth);
265 
266 /* The all-singing all-dancing load function, you normally pass NULL
267  * for the first and third parameters. Use DSO_up and DSO_free for
268  * subsequent reference count handling. Any flags passed in will be set
269  * in the constructed DSO after its init() function but before the
270  * load operation. If 'dso' is non-NULL, 'flags' is ignored. */
271 DSO *DSO_load(DSO *dso, const char *filename, DSO_METHOD *meth, int flags);
272 
273 /* This function binds to a variable inside a shared library. */
274 void *DSO_bind_var(DSO *dso, const char *symname);
275 
276 /* This function binds to a function inside a shared library. */
277 DSO_FUNC_TYPE DSO_bind_func(DSO *dso, const char *symname);
278 
279 /* This method is the default, but will beg, borrow, or steal whatever
280  * method should be the default on any particular platform (including
281  * DSO_METH_null() if necessary). */
283 
284 /* This method is defined for all platforms - if a platform has no
285  * DSO support then this will be the only method! */
287 
288 /* If DSO_DLFCN is defined, the standard dlfcn.h-style functions
289  * (dlopen, dlclose, dlsym, etc) will be used and incorporated into
290  * this method. If not, this method will return NULL. */
292 
293 /* If DSO_DL is defined, the standard dl.h-style functions (shl_load,
294  * shl_unload, shl_findsym, etc) will be used and incorporated into
295  * this method. If not, this method will return NULL. */
297 
298 /* If WIN32 is defined, use DLLs. If not, return NULL. */
300 
301 /* If VMS is defined, use shared images. If not, return NULL. */
303 
304 /* This function writes null-terminated pathname of DSO module
305  * containing 'addr' into 'sz' large caller-provided 'path' and
306  * returns the number of characters [including trailing zero]
307  * written to it. If 'sz' is 0 or negative, 'path' is ignored and
308  * required amount of charachers [including trailing zero] to
309  * accomodate pathname is returned. If 'addr' is NULL, then
310  * pathname of cryptolib itself is returned. Negative or zero
311  * return value denotes error.
312  */
313 int DSO_pathbyaddr(void *addr,char *path,int sz);
314 
315 /* This function should be used with caution! It looks up symbols in
316  * *all* loaded modules and if module gets unloaded by somebody else
317  * attempt to dereference the pointer is doomed to have fatal
318  * consequences. Primary usage for this function is to probe *core*
319  * system functionality, e.g. check if getnameinfo(3) is available
320  * at run-time without bothering about OS-specific details such as
321  * libc.so.versioning or where does it actually reside: in libc
322  * itself or libsocket. */
323 void *DSO_global_lookup(const char *name);
324 
325 /* If BeOS is defined, use shared images. If not, return NULL. */
327 
328 /* BEGIN ERROR CODES */
329 /* The following lines are auto generated by the script mkerr.pl. Any changes
330  * made after this point may be overwritten when the script is next run.
331  */
332 void ERR_load_DSO_strings(void);
333 
334 /* Error codes for the DSO functions. */
335 
336 /* Function codes. */
337 #define DSO_F_BEOS_BIND_FUNC 144
338 #define DSO_F_BEOS_BIND_VAR 145
339 #define DSO_F_BEOS_LOAD 146
340 #define DSO_F_BEOS_NAME_CONVERTER 147
341 #define DSO_F_BEOS_UNLOAD 148
342 #define DSO_F_DLFCN_BIND_FUNC 100
343 #define DSO_F_DLFCN_BIND_VAR 101
344 #define DSO_F_DLFCN_LOAD 102
345 #define DSO_F_DLFCN_MERGER 130
346 #define DSO_F_DLFCN_NAME_CONVERTER 123
347 #define DSO_F_DLFCN_UNLOAD 103
348 #define DSO_F_DL_BIND_FUNC 104
349 #define DSO_F_DL_BIND_VAR 105
350 #define DSO_F_DL_LOAD 106
351 #define DSO_F_DL_MERGER 131
352 #define DSO_F_DL_NAME_CONVERTER 124
353 #define DSO_F_DL_UNLOAD 107
354 #define DSO_F_DSO_BIND_FUNC 108
355 #define DSO_F_DSO_BIND_VAR 109
356 #define DSO_F_DSO_CONVERT_FILENAME 126
357 #define DSO_F_DSO_CTRL 110
358 #define DSO_F_DSO_FREE 111
359 #define DSO_F_DSO_GET_FILENAME 127
360 #define DSO_F_DSO_GET_LOADED_FILENAME 128
361 #define DSO_F_DSO_GLOBAL_LOOKUP 139
362 #define DSO_F_DSO_LOAD 112
363 #define DSO_F_DSO_MERGE 132
364 #define DSO_F_DSO_NEW_METHOD 113
365 #define DSO_F_DSO_PATHBYADDR 140
366 #define DSO_F_DSO_SET_FILENAME 129
367 #define DSO_F_DSO_SET_NAME_CONVERTER 122
368 #define DSO_F_DSO_UP_REF 114
369 #define DSO_F_GLOBAL_LOOKUP_FUNC 138
370 #define DSO_F_PATHBYADDR 137
371 #define DSO_F_VMS_BIND_SYM 115
372 #define DSO_F_VMS_LOAD 116
373 #define DSO_F_VMS_MERGER 133
374 #define DSO_F_VMS_UNLOAD 117
375 #define DSO_F_WIN32_BIND_FUNC 118
376 #define DSO_F_WIN32_BIND_VAR 119
377 #define DSO_F_WIN32_GLOBALLOOKUP 142
378 #define DSO_F_WIN32_GLOBALLOOKUP_FUNC 143
379 #define DSO_F_WIN32_JOINER 135
380 #define DSO_F_WIN32_LOAD 120
381 #define DSO_F_WIN32_MERGER 134
382 #define DSO_F_WIN32_NAME_CONVERTER 125
383 #define DSO_F_WIN32_PATHBYADDR 141
384 #define DSO_F_WIN32_SPLITTER 136
385 #define DSO_F_WIN32_UNLOAD 121
386 
387 /* Reason codes. */
388 #define DSO_R_CTRL_FAILED 100
389 #define DSO_R_DSO_ALREADY_LOADED 110
390 #define DSO_R_EMPTY_FILE_STRUCTURE 113
391 #define DSO_R_FAILURE 114
392 #define DSO_R_FILENAME_TOO_BIG 101
393 #define DSO_R_FINISH_FAILED 102
394 #define DSO_R_INCORRECT_FILE_SYNTAX 115
395 #define DSO_R_LOAD_FAILED 103
396 #define DSO_R_NAME_TRANSLATION_FAILED 109
397 #define DSO_R_NO_FILENAME 111
398 #define DSO_R_NO_FILE_SPECIFICATION 116
399 #define DSO_R_NULL_HANDLE 104
400 #define DSO_R_SET_FILENAME_FAILED 112
401 #define DSO_R_STACK_ERROR 105
402 #define DSO_R_SYM_FAILURE 106
403 #define DSO_R_UNLOAD_FAILED 107
404 #define DSO_R_UNSUPPORTED 108
405 
406 #ifdef __cplusplus
407 }
408 #endif
409 #endif