Structural references should never be decremented directly - so leave that
[openssl.git] / crypto / engine / engine_list.c
1 /* crypto/engine/engine_list.c */
2 /* Written by Geoff Thorpe (geoff@geoffthorpe.net) for the OpenSSL
3  * project 2000.
4  */
5 /* ====================================================================
6  * Copyright (c) 1999 The OpenSSL Project.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer. 
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in
17  *    the documentation and/or other materials provided with the
18  *    distribution.
19  *
20  * 3. All advertising materials mentioning features or use of this
21  *    software must display the following acknowledgment:
22  *    "This product includes software developed by the OpenSSL Project
23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
24  *
25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26  *    endorse or promote products derived from this software without
27  *    prior written permission. For written permission, please contact
28  *    licensing@OpenSSL.org.
29  *
30  * 5. Products derived from this software may not be called "OpenSSL"
31  *    nor may "OpenSSL" appear in their names without prior written
32  *    permission of the OpenSSL Project.
33  *
34  * 6. Redistributions of any form whatsoever must retain the following
35  *    acknowledgment:
36  *    "This product includes software developed by the OpenSSL Project
37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
38  *
39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50  * OF THE POSSIBILITY OF SUCH DAMAGE.
51  * ====================================================================
52  *
53  * This product includes cryptographic software written by Eric Young
54  * (eay@cryptsoft.com).  This product includes software written by Tim
55  * Hudson (tjh@cryptsoft.com).
56  *
57  */
58
59 #include <openssl/crypto.h>
60 #include "cryptlib.h"
61 #include "engine_int.h"
62 #include <openssl/engine.h>
63
64 /* The linked-list of pointers to engine types. engine_list_head
65  * incorporates an implicit structural reference but engine_list_tail
66  * does not - the latter is a computational niceity and only points
67  * to something that is already pointed to by its predecessor in the
68  * list (or engine_list_head itself). In the same way, the use of the
69  * "prev" pointer in each ENGINE is to save excessive list iteration,
70  * it doesn't correspond to an extra structural reference. Hence,
71  * engine_list_head, and each non-null "next" pointer account for
72  * the list itself assuming exactly 1 structural reference on each
73  * list member. */
74 static ENGINE *engine_list_head = NULL;
75 static ENGINE *engine_list_tail = NULL;
76 /* A boolean switch, used to ensure we only initialise once. This
77  * is needed because the engine list may genuinely become empty during
78  * use (so we can't use engine_list_head as an indicator for example. */
79 static int engine_list_flag = 0;
80
81 /* These static functions starting with a lower case "engine_" always
82  * take place when CRYPTO_LOCK_ENGINE has been locked up. */
83 static int engine_list_add(ENGINE *e)
84         {
85         int conflict = 0;
86         ENGINE *iterator = NULL;
87
88         if(e == NULL)
89                 {
90                 ENGINEerr(ENGINE_F_ENGINE_LIST_ADD,
91                         ERR_R_PASSED_NULL_PARAMETER);
92                 return 0;
93                 }
94         iterator = engine_list_head;
95         while(iterator && !conflict)
96                 {
97                 conflict = (strcmp(iterator->id, e->id) == 0);
98                 iterator = iterator->next;
99                 }
100         if(conflict)
101                 {
102                 ENGINEerr(ENGINE_F_ENGINE_LIST_ADD,
103                         ENGINE_R_CONFLICTING_ENGINE_ID);
104                 return 0;
105                 }
106         if(engine_list_head == NULL)
107                 {
108                 /* We are adding to an empty list. */
109                 if(engine_list_tail)
110                         {
111                         ENGINEerr(ENGINE_F_ENGINE_LIST_ADD,
112                                 ENGINE_R_INTERNAL_LIST_ERROR);
113                         return 0;
114                         }
115                 engine_list_head = e;
116                 e->prev = NULL;
117                 }
118         else
119                 {
120                 /* We are adding to the tail of an existing list. */
121                 if((engine_list_tail == NULL) ||
122                                 (engine_list_tail->next != NULL))
123                         {
124                         ENGINEerr(ENGINE_F_ENGINE_LIST_ADD,
125                                 ENGINE_R_INTERNAL_LIST_ERROR);
126                         return 0;
127                         }
128                 engine_list_tail->next = e;
129                 e->prev = engine_list_tail;
130                 }
131         /* Having the engine in the list assumes a structural
132          * reference. */
133         e->struct_ref++;
134         /* However it came to be, e is the last item in the list. */
135         engine_list_tail = e;
136         e->next = NULL;
137         return 1;
138         }
139
140 static int engine_list_remove(ENGINE *e)
141         {
142         ENGINE *iterator;
143
144         if(e == NULL)
145                 {
146                 ENGINEerr(ENGINE_F_ENGINE_LIST_REMOVE,
147                         ERR_R_PASSED_NULL_PARAMETER);
148                 return 0;
149                 }
150         /* We need to check that e is in our linked list! */
151         iterator = engine_list_head;
152         while(iterator && (iterator != e))
153                 iterator = iterator->next;
154         if(iterator == NULL)
155                 {
156                 ENGINEerr(ENGINE_F_ENGINE_LIST_REMOVE,
157                         ENGINE_R_ENGINE_IS_NOT_IN_LIST);
158                 return 0;
159                 }
160         /* un-link e from the chain. */
161         if(e->next)
162                 e->next->prev = e->prev;
163         if(e->prev)
164                 e->prev->next = e->next;
165         /* Correct our head/tail if necessary. */
166         if(engine_list_head == e)
167                 engine_list_head = e->next;
168         if(engine_list_tail == e)
169                 engine_list_tail = e->prev;
170         /* remove our structural reference. */
171         e->struct_ref--;
172         return 1;
173         }
174
175 /* This check always takes place with CRYPTO_LOCK_ENGINE locked up
176  * so we're synchronised, but we can't call anything that tries to
177  * lock it again! :-) NB: For convenience (and code-clarity) we
178  * don't output errors for failures of the engine_list_add function
179  * as it will generate errors itself. */
180 static int engine_internal_check(void)
181         {
182         if(engine_list_flag)
183                 return 1;
184         /* This is our first time up, we need to populate the list
185          * with our statically compiled-in engines. */
186         if(!engine_list_add(ENGINE_openssl()))
187                 return 0;
188         engine_list_flag = 1;
189         return 1;
190         }
191
192 /* Get the first/last "ENGINE" type available. */
193 ENGINE *ENGINE_get_first(void)
194         {
195         ENGINE *ret = NULL;
196
197         CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
198         if(engine_internal_check())
199                 {
200                 ret = engine_list_head;
201                 if(ret)
202                         ret->struct_ref++;
203                 }
204         CRYPTO_r_unlock(CRYPTO_LOCK_ENGINE);
205         return ret;
206         }
207 ENGINE *ENGINE_get_last(void)
208         {
209         ENGINE *ret = NULL;
210
211         CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
212         if(engine_internal_check())
213                 {
214                 ret = engine_list_tail;
215                 if(ret)
216                         ret->struct_ref++;
217                 }
218         CRYPTO_r_unlock(CRYPTO_LOCK_ENGINE);
219         return ret;
220         }
221
222 /* Iterate to the next/previous "ENGINE" type (NULL = end of the list). */
223 ENGINE *ENGINE_get_next(ENGINE *e)
224         {
225         ENGINE *ret = NULL;
226         if(e == NULL)
227                 {
228                 ENGINEerr(ENGINE_F_ENGINE_GET_NEXT,
229                         ERR_R_PASSED_NULL_PARAMETER);
230                 return 0;
231                 }
232         CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
233         ret = e->next;
234         if(ret)
235                 /* Return a valid structural refernce to the next ENGINE */
236                 ret->struct_ref++;
237         CRYPTO_r_unlock(CRYPTO_LOCK_ENGINE);
238         /* Release the structural reference to the previous ENGINE */
239         ENGINE_free(e);
240         return ret;
241         }
242 ENGINE *ENGINE_get_prev(ENGINE *e)
243         {
244         ENGINE *ret = NULL;
245         if(e == NULL)
246                 {
247                 ENGINEerr(ENGINE_F_ENGINE_GET_PREV,
248                         ERR_R_PASSED_NULL_PARAMETER);
249                 return 0;
250                 }
251         CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
252         ret = e->prev;
253         if(ret)
254                 /* Return a valid structural reference to the next ENGINE */
255                 ret->struct_ref++;
256         CRYPTO_r_unlock(CRYPTO_LOCK_ENGINE);
257         /* Release the structural reference to the previous ENGINE */
258         ENGINE_free(e);
259         return ret;
260         }
261
262 /* Add another "ENGINE" type into the list. */
263 int ENGINE_add(ENGINE *e)
264         {
265         int to_return = 1;
266         if(e == NULL)
267                 {
268                 ENGINEerr(ENGINE_F_ENGINE_ADD,
269                         ERR_R_PASSED_NULL_PARAMETER);
270                 return 0;
271                 }
272         if((e->id == NULL) || (e->name == NULL))
273                 {
274                 ENGINEerr(ENGINE_F_ENGINE_ADD,
275                         ENGINE_R_ID_OR_NAME_MISSING);
276                 }
277         CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
278         if(!engine_internal_check() || !engine_list_add(e))
279                 {
280                 ENGINEerr(ENGINE_F_ENGINE_ADD,
281                         ENGINE_R_INTERNAL_LIST_ERROR);
282                 to_return = 0;
283                 }
284         CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
285         return to_return;
286         }
287
288 /* Remove an existing "ENGINE" type from the array. */
289 int ENGINE_remove(ENGINE *e)
290         {
291         int to_return = 1;
292         if(e == NULL)
293                 {
294                 ENGINEerr(ENGINE_F_ENGINE_REMOVE,
295                         ERR_R_PASSED_NULL_PARAMETER);
296                 return 0;
297                 }
298         CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
299         if(!engine_internal_check() || !engine_list_remove(e))
300                 {
301                 ENGINEerr(ENGINE_F_ENGINE_REMOVE,
302                         ENGINE_R_INTERNAL_LIST_ERROR);
303                 to_return = 0;
304                 }
305         CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
306         return to_return;
307         }
308
309 ENGINE *ENGINE_by_id(const char *id)
310         {
311         ENGINE *iterator = NULL;
312         if(id == NULL)
313                 {
314                 ENGINEerr(ENGINE_F_ENGINE_BY_ID,
315                         ERR_R_PASSED_NULL_PARAMETER);
316                 return NULL;
317                 }
318         CRYPTO_r_lock(CRYPTO_LOCK_ENGINE);
319         if(!engine_internal_check())
320                 ENGINEerr(ENGINE_F_ENGINE_BY_ID,
321                         ENGINE_R_INTERNAL_LIST_ERROR);
322         else
323                 {
324                 iterator = engine_list_head;
325                 while(iterator && (strcmp(id, iterator->id) != 0))
326                         iterator = iterator->next;
327                 if(iterator)
328                         /* We need to return a structural reference */
329                         iterator->struct_ref++;
330                 }
331         CRYPTO_r_unlock(CRYPTO_LOCK_ENGINE);
332         if(iterator == NULL)
333                 ENGINEerr(ENGINE_F_ENGINE_BY_ID,
334                         ENGINE_R_NO_SUCH_ENGINE);
335         return iterator;
336         }
337
338 ENGINE *ENGINE_new(void)
339         {
340         ENGINE *ret;
341
342         ret = (ENGINE *)OPENSSL_malloc(sizeof(ENGINE));
343         if(ret == NULL)
344                 {
345                 ENGINEerr(ENGINE_F_ENGINE_NEW, ERR_R_MALLOC_FAILURE);
346                 return NULL;
347                 }
348         memset(ret, 0, sizeof(ENGINE));
349         ret->flags = ENGINE_FLAGS_MALLOCED;
350         ret->struct_ref = 1;
351         return ret;
352         }
353
354 int ENGINE_free(ENGINE *e)
355         {
356         int i;
357
358         if(e == NULL)
359                 {
360                 ENGINEerr(ENGINE_F_ENGINE_FREE,
361                         ERR_R_PASSED_NULL_PARAMETER);
362                 return 0;
363                 }
364         i = CRYPTO_add(&e->struct_ref,-1,CRYPTO_LOCK_ENGINE);
365 #ifdef REF_PRINT
366         REF_PRINT("ENGINE",e);
367 #endif
368         if (i > 0) return 1;
369 #ifdef REF_CHECK
370         if (i < 0)
371                 {
372                 fprintf(stderr,"ENGINE_free, bad reference count\n");
373                 abort();
374                 }
375 #endif
376         if(e->flags & ENGINE_FLAGS_MALLOCED)
377                 OPENSSL_free(e);
378         return 1;
379         }
380
381 int ENGINE_set_id(ENGINE *e, const char *id)
382         {
383         if((e == NULL) || (id == NULL))
384                 {
385                 ENGINEerr(ENGINE_F_ENGINE_SET_ID,
386                         ERR_R_PASSED_NULL_PARAMETER);
387                 return 0;
388                 }
389         e->id = id;
390         return 1;
391         }
392
393 int ENGINE_set_name(ENGINE *e, const char *name)
394         {
395         if((e == NULL) || (name == NULL))
396                 {
397                 ENGINEerr(ENGINE_F_ENGINE_SET_NAME,
398                         ERR_R_PASSED_NULL_PARAMETER);
399                 return 0;
400                 }
401         e->name = name;
402         return 1;
403         }
404
405 int ENGINE_set_RSA(ENGINE *e, const RSA_METHOD *rsa_meth)
406         {
407         if((e == NULL) || (rsa_meth == NULL))
408                 {
409                 ENGINEerr(ENGINE_F_ENGINE_SET_RSA,
410                         ERR_R_PASSED_NULL_PARAMETER);
411                 return 0;
412                 }
413         e->rsa_meth = rsa_meth;
414         return 1;
415         }
416
417 int ENGINE_set_DSA(ENGINE *e, const DSA_METHOD *dsa_meth)
418         {
419         if((e == NULL) || (dsa_meth == NULL))
420                 {
421                 ENGINEerr(ENGINE_F_ENGINE_SET_DSA,
422                         ERR_R_PASSED_NULL_PARAMETER);
423                 return 0;
424                 }
425         e->dsa_meth = dsa_meth;
426         return 1;
427         }
428
429 int ENGINE_set_DH(ENGINE *e, const DH_METHOD *dh_meth)
430         {
431         if((e == NULL) || (dh_meth == NULL))
432                 {
433                 ENGINEerr(ENGINE_F_ENGINE_SET_DH,
434                         ERR_R_PASSED_NULL_PARAMETER);
435                 return 0;
436                 }
437         e->dh_meth = dh_meth;
438         return 1;
439         }
440
441 int ENGINE_set_RAND(ENGINE *e, RAND_METHOD *rand_meth)
442         {
443         if((e == NULL) || (rand_meth == NULL))
444                 {
445                 ENGINEerr(ENGINE_F_ENGINE_SET_RAND,
446                         ERR_R_PASSED_NULL_PARAMETER);
447                 return 0;
448                 }
449         e->rand_meth = rand_meth;
450         return 1;
451         }
452
453 int ENGINE_set_BN_mod_exp(ENGINE *e, BN_MOD_EXP bn_mod_exp)
454         {
455         if((e == NULL) || (bn_mod_exp == NULL))
456                 {
457                 ENGINEerr(ENGINE_F_ENGINE_SET_BN_MOD_EXP,
458                         ERR_R_PASSED_NULL_PARAMETER);
459                 return 0;
460                 }
461         e->bn_mod_exp = bn_mod_exp;
462         return 1;
463         }
464
465 int ENGINE_set_BN_mod_exp_crt(ENGINE *e, BN_MOD_EXP_CRT bn_mod_exp_crt)
466         {
467         if((e == NULL) || (bn_mod_exp_crt == NULL))
468                 {
469                 ENGINEerr(ENGINE_F_ENGINE_SET_BN_MOD_EXP_CRT,
470                         ERR_R_PASSED_NULL_PARAMETER);
471                 return 0;
472                 }
473         e->bn_mod_exp_crt = bn_mod_exp_crt;
474         return 1;
475         }
476
477 int ENGINE_set_init_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR init_f)
478         {
479         if((e == NULL) || (init_f == NULL))
480                 {
481                 ENGINEerr(ENGINE_F_ENGINE_SET_INIT_FUNCTION,
482                         ERR_R_PASSED_NULL_PARAMETER);
483                 return 0;
484                 }
485         e->init = init_f;
486         return 1;
487         }
488
489 int ENGINE_set_finish_function(ENGINE *e, ENGINE_GEN_INT_FUNC_PTR finish_f)
490         {
491         if((e == NULL) || (finish_f == NULL))
492                 {
493                 ENGINEerr(ENGINE_F_ENGINE_SET_FINISH_FUNCTION,
494                         ERR_R_PASSED_NULL_PARAMETER);
495                 return 0;
496                 }
497         e->finish = finish_f;
498         return 1;
499         }
500
501 int ENGINE_set_ctrl_function(ENGINE *e, ENGINE_CTRL_FUNC_PTR ctrl_f)
502         {
503         if((e == NULL) || (ctrl_f == NULL))
504                 {
505                 ENGINEerr(ENGINE_F_ENGINE_SET_CTRL_FUNCTION,
506                         ERR_R_PASSED_NULL_PARAMETER);
507                 return 0;
508                 }
509         e->ctrl = ctrl_f;
510         return 1;
511         }
512
513 const char *ENGINE_get_id(ENGINE *e)
514         {
515         if(e == NULL)
516                 {
517                 ENGINEerr(ENGINE_F_ENGINE_GET_ID,
518                         ERR_R_PASSED_NULL_PARAMETER);
519                 return 0;
520                 }
521         return e->id;
522         }
523
524 const char *ENGINE_get_name(ENGINE *e)
525         {
526         if(e == NULL)
527                 {
528                 ENGINEerr(ENGINE_F_ENGINE_GET_NAME,
529                         ERR_R_PASSED_NULL_PARAMETER);
530                 return 0;
531                 }
532         return e->name;
533         }
534
535 const RSA_METHOD *ENGINE_get_RSA(ENGINE *e)
536         {
537         if(e == NULL)
538                 {
539                 ENGINEerr(ENGINE_F_ENGINE_GET_RSA,
540                         ERR_R_PASSED_NULL_PARAMETER);
541                 return NULL;
542                 }
543         return e->rsa_meth;
544         }
545
546 const DSA_METHOD *ENGINE_get_DSA(ENGINE *e)
547         {
548         if(e == NULL)
549                 {
550                 ENGINEerr(ENGINE_F_ENGINE_GET_DSA,
551                         ERR_R_PASSED_NULL_PARAMETER);
552                 return NULL;
553                 }
554         return e->dsa_meth;
555         }
556
557 const DH_METHOD *ENGINE_get_DH(ENGINE *e)
558         {
559         if(e == NULL)
560                 {
561                 ENGINEerr(ENGINE_F_ENGINE_GET_DH,
562                         ERR_R_PASSED_NULL_PARAMETER);
563                 return NULL;
564                 }
565         return e->dh_meth;
566         }
567
568 RAND_METHOD *ENGINE_get_RAND(ENGINE *e)
569         {
570         if(e == NULL)
571                 {
572                 ENGINEerr(ENGINE_F_ENGINE_GET_RAND,
573                         ERR_R_PASSED_NULL_PARAMETER);
574                 return NULL;
575                 }
576         return e->rand_meth;
577         }
578
579 BN_MOD_EXP ENGINE_get_BN_mod_exp(ENGINE *e)
580         {
581         if(e == NULL)
582                 {
583                 ENGINEerr(ENGINE_F_ENGINE_GET_BN_MOD_EXP,
584                         ERR_R_PASSED_NULL_PARAMETER);
585                 return NULL;
586                 }
587         return e->bn_mod_exp;
588         }
589
590 BN_MOD_EXP_CRT ENGINE_get_BN_mod_exp_crt(ENGINE *e)
591         {
592         if(e == NULL)
593                 {
594                 ENGINEerr(ENGINE_F_ENGINE_GET_BN_MOD_EXP_CRT,
595                         ERR_R_PASSED_NULL_PARAMETER);
596                 return NULL;
597                 }
598         return e->bn_mod_exp_crt;
599         }
600
601 ENGINE_GEN_INT_FUNC_PTR ENGINE_get_init_function(ENGINE *e)
602         {
603         if(e == NULL)
604                 {
605                 ENGINEerr(ENGINE_F_ENGINE_GET_INIT_FUNCTION,
606                         ERR_R_PASSED_NULL_PARAMETER);
607                 return NULL;
608                 }
609         return e->init;
610         }
611
612 ENGINE_GEN_INT_FUNC_PTR ENGINE_get_finish_function(ENGINE *e)
613         {
614         if(e == NULL)
615                 {
616                 ENGINEerr(ENGINE_F_ENGINE_GET_FINISH_FUNCTION,
617                         ERR_R_PASSED_NULL_PARAMETER);
618                 return NULL;
619                 }
620         return e->finish;
621         }
622
623 ENGINE_CTRL_FUNC_PTR ENGINE_get_ctrl_function(ENGINE *e)
624         {
625         if(e == NULL)
626                 {
627                 ENGINEerr(ENGINE_F_ENGINE_GET_CTRL_FUNCTION,
628                         ERR_R_PASSED_NULL_PARAMETER);
629                 return NULL;
630                 }
631         return e->ctrl;
632         }
633