summaryrefslogtreecommitdiff
path: root/main/openssl/crypto/engine/eng_dyn.c
blob: 807da7a5eb841c61f2edc9317a41a2558b5fc12a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
/* crypto/engine/eng_dyn.c */
/* Written by Geoff Thorpe (geoff@geoffthorpe.net) for the OpenSSL
 * project 2001.
 */
/* ====================================================================
 * Copyright (c) 1999-2001 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */


#include "eng_int.h"
#include <openssl/dso.h>

/* Shared libraries implementing ENGINEs for use by the "dynamic" ENGINE loader
 * should implement the hook-up functions with the following prototypes. */

/* Our ENGINE handlers */
static int dynamic_init(ENGINE *e);
static int dynamic_finish(ENGINE *e);
static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)(void));
/* Predeclare our context type */
typedef struct st_dynamic_data_ctx dynamic_data_ctx;
/* The implementation for the important control command */
static int dynamic_load(ENGINE *e, dynamic_data_ctx *ctx);

#define DYNAMIC_CMD_SO_PATH		ENGINE_CMD_BASE
#define DYNAMIC_CMD_NO_VCHECK		(ENGINE_CMD_BASE + 1)
#define DYNAMIC_CMD_ID			(ENGINE_CMD_BASE + 2)
#define DYNAMIC_CMD_LIST_ADD		(ENGINE_CMD_BASE + 3)
#define DYNAMIC_CMD_DIR_LOAD		(ENGINE_CMD_BASE + 4)
#define DYNAMIC_CMD_DIR_ADD		(ENGINE_CMD_BASE + 5)
#define DYNAMIC_CMD_LOAD		(ENGINE_CMD_BASE + 6)

/* The constants used when creating the ENGINE */
static const char *engine_dynamic_id = "dynamic";
static const char *engine_dynamic_name = "Dynamic engine loading support";
static const ENGINE_CMD_DEFN dynamic_cmd_defns[] = {
	{DYNAMIC_CMD_SO_PATH,
		"SO_PATH",
		"Specifies the path to the new ENGINE shared library",
		ENGINE_CMD_FLAG_STRING},
	{DYNAMIC_CMD_NO_VCHECK,
		"NO_VCHECK",
		"Specifies to continue even if version checking fails (boolean)",
		ENGINE_CMD_FLAG_NUMERIC},
	{DYNAMIC_CMD_ID,
		"ID",
		"Specifies an ENGINE id name for loading",
		ENGINE_CMD_FLAG_STRING},
	{DYNAMIC_CMD_LIST_ADD,
		"LIST_ADD",
		"Whether to add a loaded ENGINE to the internal list (0=no,1=yes,2=mandatory)",
		ENGINE_CMD_FLAG_NUMERIC},
	{DYNAMIC_CMD_DIR_LOAD,
		"DIR_LOAD",
		"Specifies whether to load from 'DIR_ADD' directories (0=no,1=yes,2=mandatory)",
		ENGINE_CMD_FLAG_NUMERIC},
	{DYNAMIC_CMD_DIR_ADD,
		"DIR_ADD",
		"Adds a directory from which ENGINEs can be loaded",
		ENGINE_CMD_FLAG_STRING},
	{DYNAMIC_CMD_LOAD,
		"LOAD",
		"Load up the ENGINE specified by other settings",
		ENGINE_CMD_FLAG_NO_INPUT},
	{0, NULL, NULL, 0}
	};
static const ENGINE_CMD_DEFN dynamic_cmd_defns_empty[] = {
	{0, NULL, NULL, 0}
	};

/* Loading code stores state inside the ENGINE structure via the "ex_data"
 * element. We load all our state into a single structure and use that as a
 * single context in the "ex_data" stack. */
struct st_dynamic_data_ctx
	{
	/* The DSO object we load that supplies the ENGINE code */
	DSO *dynamic_dso;
	/* The function pointer to the version checking shared library function */
	dynamic_v_check_fn v_check;
	/* The function pointer to the engine-binding shared library function */
	dynamic_bind_engine bind_engine;
	/* The default name/path for loading the shared library */
	const char *DYNAMIC_LIBNAME;
	/* Whether to continue loading on a version check failure */
	int no_vcheck;
	/* If non-NULL, stipulates the 'id' of the ENGINE to be loaded */
	const char *engine_id;
	/* If non-zero, a successfully loaded ENGINE should be added to the internal
	 * ENGINE list. If 2, the add must succeed or the entire load should fail. */
	int list_add_value;
	/* The symbol name for the version checking function */
	const char *DYNAMIC_F1;
	/* The symbol name for the "initialise ENGINE structure" function */
	const char *DYNAMIC_F2;
	/* Whether to never use 'dirs', use 'dirs' as a fallback, or only use
	 * 'dirs' for loading. Default is to use 'dirs' as a fallback. */
	int dir_load;
	/* A stack of directories from which ENGINEs could be loaded */
	STACK_OF(OPENSSL_STRING) *dirs;
	};

/* This is the "ex_data" index we obtain and reserve for use with our context
 * structure. */
static int dynamic_ex_data_idx = -1;

static void int_free_str(char *s) { OPENSSL_free(s); }
/* Because our ex_data element may or may not get allocated depending on whether
 * a "first-use" occurs before the ENGINE is freed, we have a memory leak
 * problem to solve. We can't declare a "new" handler for the ex_data as we
 * don't want a dynamic_data_ctx in *all* ENGINE structures of all types (this
 * is a bug in the design of CRYPTO_EX_DATA). As such, we just declare a "free"
 * handler and that will get called if an ENGINE is being destroyed and there
 * was an ex_data element corresponding to our context type. */
static void dynamic_data_ctx_free_func(void *parent, void *ptr,
			CRYPTO_EX_DATA *ad, int idx, long argl, void *argp)
	{
	if(ptr)
		{
		dynamic_data_ctx *ctx = (dynamic_data_ctx *)ptr;
		if(ctx->dynamic_dso)
			DSO_free(ctx->dynamic_dso);
		if(ctx->DYNAMIC_LIBNAME)
			OPENSSL_free((void*)ctx->DYNAMIC_LIBNAME);
		if(ctx->engine_id)
			OPENSSL_free((void*)ctx->engine_id);
		if(ctx->dirs)
			sk_OPENSSL_STRING_pop_free(ctx->dirs, int_free_str);
		OPENSSL_free(ctx);
		}
	}

/* Construct the per-ENGINE context. We create it blindly and then use a lock to
 * check for a race - if so, all but one of the threads "racing" will have
 * wasted their time. The alternative involves creating everything inside the
 * lock which is far worse. */
static int dynamic_set_data_ctx(ENGINE *e, dynamic_data_ctx **ctx)
	{
	dynamic_data_ctx *c;
	c = OPENSSL_malloc(sizeof(dynamic_data_ctx));
	if(!c)
		{
		ENGINEerr(ENGINE_F_DYNAMIC_SET_DATA_CTX,ERR_R_MALLOC_FAILURE);
		return 0;
		}
	memset(c, 0, sizeof(dynamic_data_ctx));
	c->dynamic_dso = NULL;
	c->v_check = NULL;
	c->bind_engine = NULL;
	c->DYNAMIC_LIBNAME = NULL;
	c->no_vcheck = 0;
	c->engine_id = NULL;
	c->list_add_value = 0;
	c->DYNAMIC_F1 = "v_check";
	c->DYNAMIC_F2 = "bind_engine";
	c->dir_load = 1;
	c->dirs = sk_OPENSSL_STRING_new_null();
	if(!c->dirs)
		{
		ENGINEerr(ENGINE_F_DYNAMIC_SET_DATA_CTX,ERR_R_MALLOC_FAILURE);
		OPENSSL_free(c);
		return 0;
		}
	CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
	if((*ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e,
				dynamic_ex_data_idx)) == NULL)
		{
		/* Good, we're the first */
		ENGINE_set_ex_data(e, dynamic_ex_data_idx, c);
		*ctx = c;
		c = NULL;
		}
	CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
	/* If we lost the race to set the context, c is non-NULL and *ctx is the
	 * context of the thread that won. */
	if(c)
		OPENSSL_free(c);
	return 1;
	}

/* This function retrieves the context structure from an ENGINE's "ex_data", or
 * if it doesn't exist yet, sets it up. */
static dynamic_data_ctx *dynamic_get_data_ctx(ENGINE *e)
	{
	dynamic_data_ctx *ctx;
	if(dynamic_ex_data_idx < 0)
		{
		/* Create and register the ENGINE ex_data, and associate our
		 * "free" function with it to ensure any allocated contexts get
		 * freed when an ENGINE goes underground. */
		int new_idx = ENGINE_get_ex_new_index(0, NULL, NULL, NULL,
					dynamic_data_ctx_free_func);
		if(new_idx == -1)
			{
			ENGINEerr(ENGINE_F_DYNAMIC_GET_DATA_CTX,ENGINE_R_NO_INDEX);
			return NULL;
			}
		CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
		/* Avoid a race by checking again inside this lock */
		if(dynamic_ex_data_idx < 0)
			{
			/* Good, someone didn't beat us to it */
			dynamic_ex_data_idx = new_idx;
			new_idx = -1;
			}
		CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
		/* In theory we could "give back" the index here if
		 * (new_idx>-1), but it's not possible and wouldn't gain us much
		 * if it were. */
		}
	ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e, dynamic_ex_data_idx);
	/* Check if the context needs to be created */
	if((ctx == NULL) && !dynamic_set_data_ctx(e, &ctx))
		/* "set_data" will set errors if necessary */
		return NULL;
	return ctx;
	}

static ENGINE *engine_dynamic(void)
	{
	ENGINE *ret = ENGINE_new();
	if(!ret)
		return NULL;
	if(!ENGINE_set_id(ret, engine_dynamic_id) ||
			!ENGINE_set_name(ret, engine_dynamic_name) ||
			!ENGINE_set_init_function(ret, dynamic_init) ||
			!ENGINE_set_finish_function(ret, dynamic_finish) ||
			!ENGINE_set_ctrl_function(ret, dynamic_ctrl) ||
			!ENGINE_set_flags(ret, ENGINE_FLAGS_BY_ID_COPY) ||
			!ENGINE_set_cmd_defns(ret, dynamic_cmd_defns))
		{
		ENGINE_free(ret);
		return NULL;
		}
	return ret;
	}

void ENGINE_load_dynamic(void)
	{
	ENGINE *toadd = engine_dynamic();
	if(!toadd) return;
	ENGINE_add(toadd);
	/* If the "add" worked, it gets a structural reference. So either way,
	 * we release our just-created reference. */
	ENGINE_free(toadd);
	/* If the "add" didn't work, it was probably a conflict because it was
	 * already added (eg. someone calling ENGINE_load_blah then calling
	 * ENGINE_load_builtin_engines() perhaps). */
	ERR_clear_error();
	}

static int dynamic_init(ENGINE *e)
	{
	/* We always return failure - the "dyanamic" engine itself can't be used
	 * for anything. */
	return 0;
	}

static int dynamic_finish(ENGINE *e)
	{
	/* This should never be called on account of "dynamic_init" always
	 * failing. */
	return 0;
	}

static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)(void))
	{
	dynamic_data_ctx *ctx = dynamic_get_data_ctx(e);
	int initialised;
	
	if(!ctx)
		{
		ENGINEerr(ENGINE_F_DYNAMIC_CTRL,ENGINE_R_NOT_LOADED);
		return 0;
		}
	initialised = ((ctx->dynamic_dso == NULL) ? 0 : 1);
	/* All our control commands require the ENGINE to be uninitialised */
	if(initialised)
		{
		ENGINEerr(ENGINE_F_DYNAMIC_CTRL,
			ENGINE_R_ALREADY_LOADED);
		return 0;
		}
	switch(cmd)
		{
	case DYNAMIC_CMD_SO_PATH:
		/* a NULL 'p' or a string of zero-length is the same thing */
		if(p && (strlen((const char *)p) < 1))
			p = NULL;
		if(ctx->DYNAMIC_LIBNAME)
			OPENSSL_free((void*)ctx->DYNAMIC_LIBNAME);
		if(p)
			ctx->DYNAMIC_LIBNAME = BUF_strdup(p);
		else
			ctx->DYNAMIC_LIBNAME = NULL;
		return (ctx->DYNAMIC_LIBNAME ? 1 : 0);
	case DYNAMIC_CMD_NO_VCHECK:
		ctx->no_vcheck = ((i == 0) ? 0 : 1);
		return 1;
	case DYNAMIC_CMD_ID:
		/* a NULL 'p' or a string of zero-length is the same thing */
		if(p && (strlen((const char *)p) < 1))
			p = NULL;
		if(ctx->engine_id)
			OPENSSL_free((void*)ctx->engine_id);
		if(p)
			ctx->engine_id = BUF_strdup(p);
		else
			ctx->engine_id = NULL;
		return (ctx->engine_id ? 1 : 0);
	case DYNAMIC_CMD_LIST_ADD:
		if((i < 0) || (i > 2))
			{
			ENGINEerr(ENGINE_F_DYNAMIC_CTRL,
				ENGINE_R_INVALID_ARGUMENT);
			return 0;
			}
		ctx->list_add_value = (int)i;
		return 1;
	case DYNAMIC_CMD_LOAD:
		return dynamic_load(e, ctx);
	case DYNAMIC_CMD_DIR_LOAD:
		if((i < 0) || (i > 2))
			{
			ENGINEerr(ENGINE_F_DYNAMIC_CTRL,
				ENGINE_R_INVALID_ARGUMENT);
			return 0;
			}
		ctx->dir_load = (int)i;
		return 1;
	case DYNAMIC_CMD_DIR_ADD:
		/* a NULL 'p' or a string of zero-length is the same thing */
		if(!p || (strlen((const char *)p) < 1))
			{
			ENGINEerr(ENGINE_F_DYNAMIC_CTRL,
				ENGINE_R_INVALID_ARGUMENT);
			return 0;
			}
		{
		char *tmp_str = BUF_strdup(p);
		if(!tmp_str)
			{
			ENGINEerr(ENGINE_F_DYNAMIC_CTRL,
				ERR_R_MALLOC_FAILURE);
			return 0;
			}
		sk_OPENSSL_STRING_insert(ctx->dirs, tmp_str, -1);
		}
		return 1;
	default:
		break;
		}
	ENGINEerr(ENGINE_F_DYNAMIC_CTRL,ENGINE_R_CTRL_COMMAND_NOT_IMPLEMENTED);
	return 0;
	}

static int int_load(dynamic_data_ctx *ctx)
	{
	int num, loop;
	/* Unless told not to, try a direct load */
	if((ctx->dir_load != 2) && (DSO_load(ctx->dynamic_dso,
				ctx->DYNAMIC_LIBNAME, NULL, 0)) != NULL)
		return 1;
	/* If we're not allowed to use 'dirs' or we have none, fail */
	if(!ctx->dir_load || (num = sk_OPENSSL_STRING_num(ctx->dirs)) < 1)
		return 0;
	for(loop = 0; loop < num; loop++)
		{
		const char *s = sk_OPENSSL_STRING_value(ctx->dirs, loop);
		char *merge = DSO_merge(ctx->dynamic_dso, ctx->DYNAMIC_LIBNAME, s);
		if(!merge)
			return 0;
		if(DSO_load(ctx->dynamic_dso, merge, NULL, 0))
			{
			/* Found what we're looking for */
			OPENSSL_free(merge);
			return 1;
			}
		OPENSSL_free(merge);
		}
	return 0;
	}

static int dynamic_load(ENGINE *e, dynamic_data_ctx *ctx)
	{
	ENGINE cpy;
	dynamic_fns fns;

	if(!ctx->dynamic_dso)
		ctx->dynamic_dso = DSO_new();
	if(!ctx->DYNAMIC_LIBNAME)
		{
		if(!ctx->engine_id)
			return 0;
		ctx->DYNAMIC_LIBNAME =
			DSO_convert_filename(ctx->dynamic_dso, ctx->engine_id);
		}
	if(!int_load(ctx))
		{
		ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
			ENGINE_R_DSO_NOT_FOUND);
		DSO_free(ctx->dynamic_dso);
		ctx->dynamic_dso = NULL;
		return 0;
		}
	/* We have to find a bind function otherwise it'll always end badly */
	if(!(ctx->bind_engine = (dynamic_bind_engine)DSO_bind_func(
					ctx->dynamic_dso, ctx->DYNAMIC_F2)))
		{
		ctx->bind_engine = NULL;
		DSO_free(ctx->dynamic_dso);
		ctx->dynamic_dso = NULL;
		ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
			ENGINE_R_DSO_FAILURE);
		return 0;
		}
	/* Do we perform version checking? */
	if(!ctx->no_vcheck)
		{
		unsigned long vcheck_res = 0;
		/* Now we try to find a version checking function and decide how
		 * to cope with failure if/when it fails. */
		ctx->v_check = (dynamic_v_check_fn)DSO_bind_func(
				ctx->dynamic_dso, ctx->DYNAMIC_F1);
		if(ctx->v_check)
			vcheck_res = ctx->v_check(OSSL_DYNAMIC_VERSION);
		/* We fail if the version checker veto'd the load *or* if it is
		 * deferring to us (by returning its version) and we think it is
		 * too old. */
		if(vcheck_res < OSSL_DYNAMIC_OLDEST)
			{
			/* Fail */
			ctx->bind_engine = NULL;
			ctx->v_check = NULL;
			DSO_free(ctx->dynamic_dso);
			ctx->dynamic_dso = NULL;
			ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
				ENGINE_R_VERSION_INCOMPATIBILITY);
			return 0;
			}
		}
	/* First binary copy the ENGINE structure so that we can roll back if
	 * the hand-over fails */
	memcpy(&cpy, e, sizeof(ENGINE));
	/* Provide the ERR, "ex_data", memory, and locking callbacks so the
	 * loaded library uses our state rather than its own. FIXME: As noted in
	 * engine.h, much of this would be simplified if each area of code
	 * provided its own "summary" structure of all related callbacks. It
	 * would also increase opaqueness. */
	fns.static_state = ENGINE_get_static_state();
	fns.err_fns = ERR_get_implementation();
	fns.ex_data_fns = CRYPTO_get_ex_data_implementation();
	CRYPTO_get_mem_functions(&fns.mem_fns.malloc_cb,
				&fns.mem_fns.realloc_cb,
				&fns.mem_fns.free_cb);
	fns.lock_fns.lock_locking_cb = CRYPTO_get_locking_callback();
	fns.lock_fns.lock_add_lock_cb = CRYPTO_get_add_lock_callback();
	fns.lock_fns.dynlock_create_cb = CRYPTO_get_dynlock_create_callback();
	fns.lock_fns.dynlock_lock_cb = CRYPTO_get_dynlock_lock_callback();
	fns.lock_fns.dynlock_destroy_cb = CRYPTO_get_dynlock_destroy_callback();
	/* Now that we've loaded the dynamic engine, make sure no "dynamic"
	 * ENGINE elements will show through. */
	engine_set_all_null(e);

	/* Try to bind the ENGINE onto our own ENGINE structure */
	if(!ctx->bind_engine(e, ctx->engine_id, &fns))
		{
		ctx->bind_engine = NULL;
		ctx->v_check = NULL;
		DSO_free(ctx->dynamic_dso);
		ctx->dynamic_dso = NULL;
		ENGINEerr(ENGINE_F_DYNAMIC_LOAD,ENGINE_R_INIT_FAILED);
		/* Copy the original ENGINE structure back */
		memcpy(e, &cpy, sizeof(ENGINE));
		return 0;
		}
	/* Do we try to add this ENGINE to the internal list too? */
	if(ctx->list_add_value > 0)
		{
		if(!ENGINE_add(e))
			{
			/* Do we tolerate this or fail? */
			if(ctx->list_add_value > 1)
				{
				/* Fail - NB: By this time, it's too late to
				 * rollback, and trying to do so allows the
				 * bind_engine() code to have created leaks. We
				 * just have to fail where we are, after the
				 * ENGINE has changed. */
				ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
					ENGINE_R_CONFLICTING_ENGINE_ID);
				return 0;
				}
			/* Tolerate */
			ERR_clear_error();
			}
		}
	return 1;
	}