/src/openssl30/crypto/engine/eng_ctrl.c

Source (jump to first uncovered line)
/*
 * Copyright 2001-2021 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/* We need to use some engine deprecated APIs */
#define OPENSSL_SUPPRESS_DEPRECATED

#include "eng_local.h"

/*
 * When querying a ENGINE-specific control command's 'description', this
 * string is used if the ENGINE_CMD_DEFN has cmd_desc set to NULL.
 */
static const char *int_no_description = "";

/*
 * These internal functions handle 'CMD'-related control commands when the
 * ENGINE in question has asked us to take care of it (ie. the ENGINE did not
 * set the ENGINE_FLAGS_MANUAL_CMD_CTRL flag.
 */

static int int_ctrl_cmd_is_null(const ENGINE_CMD_DEFN *defn)
{
    if ((defn->cmd_num == 0) || (defn->cmd_name == NULL))
        return 1;
    return 0;
}

static int int_ctrl_cmd_by_name(const ENGINE_CMD_DEFN *defn, const char *s)
{
    int idx = 0;
    while (!int_ctrl_cmd_is_null(defn) && (strcmp(defn->cmd_name, s) != 0)) {
        idx++;
        defn++;
    }
    if (int_ctrl_cmd_is_null(defn))
        /* The given name wasn't found */
        return -1;
    return idx;
}

static int int_ctrl_cmd_by_num(const ENGINE_CMD_DEFN *defn, unsigned int num)
{
    int idx = 0;
    /*
     * NB: It is stipulated that 'cmd_defn' lists are ordered by cmd_num. So
     * our searches don't need to take any longer than necessary.
     */
    while (!int_ctrl_cmd_is_null(defn) && (defn->cmd_num < num)) {
        idx++;
        defn++;
    }
    if (defn->cmd_num == num)
        return idx;
    /* The given cmd_num wasn't found */
    return -1;
}

static int int_ctrl_helper(ENGINE *e, int cmd, long i, void *p,
                           void (*f) (void))
{
    int idx;
    char *s = (char *)p;
    const ENGINE_CMD_DEFN *cdp;

    /* Take care of the easy one first (eg. it requires no searches) */
    if (cmd == ENGINE_CTRL_GET_FIRST_CMD_TYPE) {
        if ((e->cmd_defns == NULL) || int_ctrl_cmd_is_null(e->cmd_defns))
            return 0;
        return e->cmd_defns->cmd_num;
    }
    /* One or two commands require that "p" be a valid string buffer */
    if ((cmd == ENGINE_CTRL_GET_CMD_FROM_NAME) ||
        (cmd == ENGINE_CTRL_GET_NAME_FROM_CMD) ||
        (cmd == ENGINE_CTRL_GET_DESC_FROM_CMD)) {
        if (s == NULL) {
            ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
            return -1;
        }
    }
    /* Now handle cmd_name -> cmd_num conversion */
    if (cmd == ENGINE_CTRL_GET_CMD_FROM_NAME) {
        if ((e->cmd_defns == NULL)
            || ((idx = int_ctrl_cmd_by_name(e->cmd_defns, s)) < 0)) {
            ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INVALID_CMD_NAME);
            return -1;
        }
        return e->cmd_defns[idx].cmd_num;
    }
    /*
     * For the rest of the commands, the 'long' argument must specify a valid
     * command number - so we need to conduct a search.
     */
    if ((e->cmd_defns == NULL)
        || ((idx = int_ctrl_cmd_by_num(e->cmd_defns, (unsigned int)i)) < 0)) {
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INVALID_CMD_NUMBER);
        return -1;
    }
    /* Now the logic splits depending on command type */
    cdp = &e->cmd_defns[idx];
    switch (cmd) {
    case ENGINE_CTRL_GET_NEXT_CMD_TYPE:
        cdp++;
        return int_ctrl_cmd_is_null(cdp) ? 0 : cdp->cmd_num;
    case ENGINE_CTRL_GET_NAME_LEN_FROM_CMD:
        return strlen(cdp->cmd_name);
    case ENGINE_CTRL_GET_NAME_FROM_CMD:
        return strlen(strcpy(s, cdp->cmd_name));
    case ENGINE_CTRL_GET_DESC_LEN_FROM_CMD:
        return strlen(cdp->cmd_desc == NULL ? int_no_description
                                            : cdp->cmd_desc);
    case ENGINE_CTRL_GET_DESC_FROM_CMD:
        return strlen(strcpy(s, cdp->cmd_desc == NULL ? int_no_description
                                                      : cdp->cmd_desc));
    case ENGINE_CTRL_GET_CMD_FLAGS:
        return cdp->cmd_flags;
    }
    /* Shouldn't really be here ... */
    ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
    return -1;
}

int ENGINE_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
{
    int ctrl_exists, ref_exists;
    if (e == NULL) {
        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
        return 0;
    }
    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
        return 0;
    ref_exists = ((e->struct_ref > 0) ? 1 : 0);
    CRYPTO_THREAD_unlock(global_engine_lock);
    ctrl_exists = ((e->ctrl == NULL) ? 0 : 1);
    if (!ref_exists) {
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NO_REFERENCE);
        return 0;
    }
    /*
     * Intercept any "root-level" commands before trying to hand them on to
     * ctrl() handlers.
     */
    switch (cmd) {
    case ENGINE_CTRL_HAS_CTRL_FUNCTION:
        return ctrl_exists;
    case ENGINE_CTRL_GET_FIRST_CMD_TYPE:
    case ENGINE_CTRL_GET_NEXT_CMD_TYPE:
    case ENGINE_CTRL_GET_CMD_FROM_NAME:
    case ENGINE_CTRL_GET_NAME_LEN_FROM_CMD:
    case ENGINE_CTRL_GET_NAME_FROM_CMD:
    case ENGINE_CTRL_GET_DESC_LEN_FROM_CMD:
    case ENGINE_CTRL_GET_DESC_FROM_CMD:
    case ENGINE_CTRL_GET_CMD_FLAGS:
        if (ctrl_exists && !(e->flags & ENGINE_FLAGS_MANUAL_CMD_CTRL))
            return int_ctrl_helper(e, cmd, i, p, f);
        if (!ctrl_exists) {
            ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NO_CONTROL_FUNCTION);
            /*
             * For these cmd-related functions, failure is indicated by a -1
             * return value (because 0 is used as a valid return in some
             * places).
             */
            return -1;
        }
    default:
        break;
    }
    /* Anything else requires a ctrl() handler to exist. */
    if (!ctrl_exists) {
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NO_CONTROL_FUNCTION);
        return 0;
    }
    return e->ctrl(e, cmd, i, p, f);
}

int ENGINE_cmd_is_executable(ENGINE *e, int cmd)
{
    int flags;
    if ((flags =
         ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, cmd, NULL, NULL)) < 0) {
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INVALID_CMD_NUMBER);
        return 0;
    }
    if (!(flags & ENGINE_CMD_FLAG_NO_INPUT) &&
        !(flags & ENGINE_CMD_FLAG_NUMERIC) &&
        !(flags & ENGINE_CMD_FLAG_STRING))
        return 0;
    return 1;
}

int ENGINE_ctrl_cmd(ENGINE *e, const char *cmd_name,
                    long i, void *p, void (*f) (void), int cmd_optional)
{
    int num;

    if (e == NULL || cmd_name == NULL) {
        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
        return 0;
    }
    if (e->ctrl == NULL
        || (num = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FROM_NAME,
                              0, (void *)cmd_name, NULL)) <= 0) {
        /*
         * If the command didn't *have* to be supported, we fake success.
         * This allows certain settings to be specified for multiple ENGINEs
         * and only require a change of ENGINE id (without having to
         * selectively apply settings). Eg. changing from a hardware device
         * back to the regular software ENGINE without editing the config
         * file, etc.
         */
        if (cmd_optional) {
            ERR_clear_error();
            return 1;
        }
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INVALID_CMD_NAME);
        return 0;
    }
    /*
     * Force the result of the control command to 0 or 1, for the reasons
     * mentioned before.
     */
    if (ENGINE_ctrl(e, num, i, p, f) > 0)
        return 1;
    return 0;
}

int ENGINE_ctrl_cmd_string(ENGINE *e, const char *cmd_name, const char *arg,
                           int cmd_optional)
{
    int num, flags;
    long l;
    char *ptr;

    if (e == NULL || cmd_name == NULL) {
        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
        return 0;
    }
    if (e->ctrl == NULL
        || (num = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FROM_NAME,
                              0, (void *)cmd_name, NULL)) <= 0) {
        /*
         * If the command didn't *have* to be supported, we fake success.
         * This allows certain settings to be specified for multiple ENGINEs
         * and only require a change of ENGINE id (without having to
         * selectively apply settings). Eg. changing from a hardware device
         * back to the regular software ENGINE without editing the config
         * file, etc.
         */
        if (cmd_optional) {
            ERR_clear_error();
            return 1;
        }
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INVALID_CMD_NAME);
        return 0;
    }
    if (!ENGINE_cmd_is_executable(e, num)) {
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_CMD_NOT_EXECUTABLE);
        return 0;
    }

    flags = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, num, NULL, NULL);
    if (flags < 0) {
        /*
         * Shouldn't happen, given that ENGINE_cmd_is_executable() returned
         * success.
         */
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
        return 0;
    }
    /*
     * If the command takes no input, there must be no input. And vice versa.
     */
    if (flags & ENGINE_CMD_FLAG_NO_INPUT) {
        if (arg != NULL) {
            ERR_raise(ERR_LIB_ENGINE, ENGINE_R_COMMAND_TAKES_NO_INPUT);
            return 0;
        }
        /*
         * We deliberately force the result of ENGINE_ctrl() to 0 or 1 rather
         * than returning it as "return data". This is to ensure usage of
         * these commands is consistent across applications and that certain
         * applications don't understand it one way, and others another.
         */
        if (ENGINE_ctrl(e, num, 0, (void *)arg, NULL) > 0)
            return 1;
        return 0;
    }
    /* So, we require input */
    if (arg == NULL) {
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_COMMAND_TAKES_INPUT);
        return 0;
    }
    /* If it takes string input, that's easy */
    if (flags & ENGINE_CMD_FLAG_STRING) {
        /* Same explanation as above */
        if (ENGINE_ctrl(e, num, 0, (void *)arg, NULL) > 0)
            return 1;
        return 0;
    }
    /*
     * If it doesn't take numeric either, then it is unsupported for use in a
     * config-setting situation, which is what this function is for. This
     * should never happen though, because ENGINE_cmd_is_executable() was
     * used.
     */
    if (!(flags & ENGINE_CMD_FLAG_NUMERIC)) {
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
        return 0;
    }
    l = strtol(arg, &ptr, 10);
    if ((arg == ptr) || (*ptr != '\0')) {
        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_ARGUMENT_IS_NOT_A_NUMBER);
        return 0;
    }
    /*
     * Force the result of the control command to 0 or 1, for the reasons
     * mentioned before.
     */
    if (ENGINE_ctrl(e, num, l, NULL, NULL) > 0)
        return 1;
    return 0;
}

Coverage Report

Created: 2025-06-13 06:58

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 2001-2021 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		/* We need to use some engine deprecated APIs */
11		#define OPENSSL_SUPPRESS_DEPRECATED
12
13		#include "eng_local.h"
14
15		/*
16		* When querying a ENGINE-specific control command's 'description', this
17		* string is used if the ENGINE_CMD_DEFN has cmd_desc set to NULL.
18		*/
19		static const char *int_no_description = "";
20
21		/*
22		* These internal functions handle 'CMD'-related control commands when the
23		* ENGINE in question has asked us to take care of it (ie. the ENGINE did not
24		* set the ENGINE_FLAGS_MANUAL_CMD_CTRL flag.
25		*/
26
27		static int int_ctrl_cmd_is_null(const ENGINE_CMD_DEFN *defn)
28	0	{
29	0	if ((defn->cmd_num == 0) \|\| (defn->cmd_name == NULL))
30	0	return 1;
31	0	return 0;
32	0	}
33
34		static int int_ctrl_cmd_by_name(const ENGINE_CMD_DEFN defn, const char s)
35	0	{
36	0	int idx = 0;
37	0	while (!int_ctrl_cmd_is_null(defn) && (strcmp(defn->cmd_name, s) != 0)) {
38	0	idx++;
39	0	defn++;
40	0	}
41	0	if (int_ctrl_cmd_is_null(defn))
42		/* The given name wasn't found */
43	0	return -1;
44	0	return idx;
45	0	}
46
47		static int int_ctrl_cmd_by_num(const ENGINE_CMD_DEFN *defn, unsigned int num)
48	0	{
49	0	int idx = 0;
50		/*
51		* NB: It is stipulated that 'cmd_defn' lists are ordered by cmd_num. So
52		* our searches don't need to take any longer than necessary.
53		*/
54	0	while (!int_ctrl_cmd_is_null(defn) && (defn->cmd_num < num)) {
55	0	idx++;
56	0	defn++;
57	0	}
58	0	if (defn->cmd_num == num)
59	0	return idx;
60		/* The given cmd_num wasn't found */
61	0	return -1;
62	0	}
63
64		static int int_ctrl_helper(ENGINE e, int cmd, long i, void p,
65		void (*f) (void))
66	0	{
67	0	int idx;
68	0	char s = (char )p;
69	0	const ENGINE_CMD_DEFN *cdp;
70
71		/* Take care of the easy one first (eg. it requires no searches) */
72	0	if (cmd == ENGINE_CTRL_GET_FIRST_CMD_TYPE) {
73	0	if ((e->cmd_defns == NULL) \|\| int_ctrl_cmd_is_null(e->cmd_defns))
74	0	return 0;
75	0	return e->cmd_defns->cmd_num;
76	0	}
77		/* One or two commands require that "p" be a valid string buffer */
78	0	if ((cmd == ENGINE_CTRL_GET_CMD_FROM_NAME) \|\|
79	0	(cmd == ENGINE_CTRL_GET_NAME_FROM_CMD) \|\|
80	0	(cmd == ENGINE_CTRL_GET_DESC_FROM_CMD)) {
81	0	if (s == NULL) {
82	0	ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
83	0	return -1;
84	0	}
85	0	}
86		/* Now handle cmd_name -> cmd_num conversion */
87	0	if (cmd == ENGINE_CTRL_GET_CMD_FROM_NAME) {
88	0	if ((e->cmd_defns == NULL)
89	0	\|\| ((idx = int_ctrl_cmd_by_name(e->cmd_defns, s)) < 0)) {
90	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INVALID_CMD_NAME);
91	0	return -1;
92	0	}
93	0	return e->cmd_defns[idx].cmd_num;
94	0	}
95		/*
96		* For the rest of the commands, the 'long' argument must specify a valid
97		* command number - so we need to conduct a search.
98		*/
99	0	if ((e->cmd_defns == NULL)
100	0	\|\| ((idx = int_ctrl_cmd_by_num(e->cmd_defns, (unsigned int)i)) < 0)) {
101	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INVALID_CMD_NUMBER);
102	0	return -1;
103	0	}
104		/* Now the logic splits depending on command type */
105	0	cdp = &e->cmd_defns[idx];
106	0	switch (cmd) {
107	0	case ENGINE_CTRL_GET_NEXT_CMD_TYPE:
108	0	cdp++;
109	0	return int_ctrl_cmd_is_null(cdp) ? 0 : cdp->cmd_num;
110	0	case ENGINE_CTRL_GET_NAME_LEN_FROM_CMD:
111	0	return strlen(cdp->cmd_name);
112	0	case ENGINE_CTRL_GET_NAME_FROM_CMD:
113	0	return strlen(strcpy(s, cdp->cmd_name));
114	0	case ENGINE_CTRL_GET_DESC_LEN_FROM_CMD:
115	0	return strlen(cdp->cmd_desc == NULL ? int_no_description
116	0	: cdp->cmd_desc);
117	0	case ENGINE_CTRL_GET_DESC_FROM_CMD:
118	0	return strlen(strcpy(s, cdp->cmd_desc == NULL ? int_no_description
119	0	: cdp->cmd_desc));
120	0	case ENGINE_CTRL_GET_CMD_FLAGS:
121	0	return cdp->cmd_flags;
122	0	}
123		/* Shouldn't really be here ... */
124	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
125	0	return -1;
126	0	}
127
128		int ENGINE_ctrl(ENGINE e, int cmd, long i, void p, void (*f) (void))
129	0	{
130	0	int ctrl_exists, ref_exists;
131	0	if (e == NULL) {
132	0	ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
133	0	return 0;
134	0	}
135	0	if (!CRYPTO_THREAD_write_lock(global_engine_lock))
136	0	return 0;
137	0	ref_exists = ((e->struct_ref > 0) ? 1 : 0);
138	0	CRYPTO_THREAD_unlock(global_engine_lock);
139	0	ctrl_exists = ((e->ctrl == NULL) ? 0 : 1);
140	0	if (!ref_exists) {
141	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NO_REFERENCE);
142	0	return 0;
143	0	}
144		/*
145		* Intercept any "root-level" commands before trying to hand them on to
146		* ctrl() handlers.
147		*/
148	0	switch (cmd) {
149	0	case ENGINE_CTRL_HAS_CTRL_FUNCTION:
150	0	return ctrl_exists;
151	0	case ENGINE_CTRL_GET_FIRST_CMD_TYPE:
152	0	case ENGINE_CTRL_GET_NEXT_CMD_TYPE:
153	0	case ENGINE_CTRL_GET_CMD_FROM_NAME:
154	0	case ENGINE_CTRL_GET_NAME_LEN_FROM_CMD:
155	0	case ENGINE_CTRL_GET_NAME_FROM_CMD:
156	0	case ENGINE_CTRL_GET_DESC_LEN_FROM_CMD:
157	0	case ENGINE_CTRL_GET_DESC_FROM_CMD:
158	0	case ENGINE_CTRL_GET_CMD_FLAGS:
159	0	if (ctrl_exists && !(e->flags & ENGINE_FLAGS_MANUAL_CMD_CTRL))
160	0	return int_ctrl_helper(e, cmd, i, p, f);
161	0	if (!ctrl_exists) {
162	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NO_CONTROL_FUNCTION);
163		/*
164		* For these cmd-related functions, failure is indicated by a -1
165		* return value (because 0 is used as a valid return in some
166		* places).
167		*/
168	0	return -1;
169	0	}
170	0	default:
171	0	break;
172	0	}
173		/* Anything else requires a ctrl() handler to exist. */
174	0	if (!ctrl_exists) {
175	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NO_CONTROL_FUNCTION);
176	0	return 0;
177	0	}
178	0	return e->ctrl(e, cmd, i, p, f);
179	0	}
180
181		int ENGINE_cmd_is_executable(ENGINE *e, int cmd)
182	0	{
183	0	int flags;
184	0	if ((flags =
185	0	ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, cmd, NULL, NULL)) < 0) {
186	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INVALID_CMD_NUMBER);
187	0	return 0;
188	0	}
189	0	if (!(flags & ENGINE_CMD_FLAG_NO_INPUT) &&
190	0	!(flags & ENGINE_CMD_FLAG_NUMERIC) &&
191	0	!(flags & ENGINE_CMD_FLAG_STRING))
192	0	return 0;
193	0	return 1;
194	0	}
195
196		int ENGINE_ctrl_cmd(ENGINE e, const char cmd_name,
197		long i, void p, void (f) (void), int cmd_optional)
198	0	{
199	0	int num;
200
201	0	if (e == NULL \|\| cmd_name == NULL) {
202	0	ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
203	0	return 0;
204	0	}
205	0	if (e->ctrl == NULL
206	0	\|\| (num = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FROM_NAME,
207	0	0, (void *)cmd_name, NULL)) <= 0) {
208		/*
209		* If the command didn't have to be supported, we fake success.
210		* This allows certain settings to be specified for multiple ENGINEs
211		* and only require a change of ENGINE id (without having to
212		* selectively apply settings). Eg. changing from a hardware device
213		* back to the regular software ENGINE without editing the config
214		* file, etc.
215		*/
216	0	if (cmd_optional) {
217	0	ERR_clear_error();
218	0	return 1;
219	0	}
220	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INVALID_CMD_NAME);
221	0	return 0;
222	0	}
223		/*
224		* Force the result of the control command to 0 or 1, for the reasons
225		* mentioned before.
226		*/
227	0	if (ENGINE_ctrl(e, num, i, p, f) > 0)
228	0	return 1;
229	0	return 0;
230	0	}
231
232		int ENGINE_ctrl_cmd_string(ENGINE e, const char cmd_name, const char *arg,
233		int cmd_optional)
234	0	{
235	0	int num, flags;
236	0	long l;
237	0	char *ptr;
238
239	0	if (e == NULL \|\| cmd_name == NULL) {
240	0	ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
241	0	return 0;
242	0	}
243	0	if (e->ctrl == NULL
244	0	\|\| (num = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FROM_NAME,
245	0	0, (void *)cmd_name, NULL)) <= 0) {
246		/*
247		* If the command didn't have to be supported, we fake success.
248		* This allows certain settings to be specified for multiple ENGINEs
249		* and only require a change of ENGINE id (without having to
250		* selectively apply settings). Eg. changing from a hardware device
251		* back to the regular software ENGINE without editing the config
252		* file, etc.
253		*/
254	0	if (cmd_optional) {
255	0	ERR_clear_error();
256	0	return 1;
257	0	}
258	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INVALID_CMD_NAME);
259	0	return 0;
260	0	}
261	0	if (!ENGINE_cmd_is_executable(e, num)) {
262	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_CMD_NOT_EXECUTABLE);
263	0	return 0;
264	0	}
265
266	0	flags = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, num, NULL, NULL);
267	0	if (flags < 0) {
268		/*
269		* Shouldn't happen, given that ENGINE_cmd_is_executable() returned
270		* success.
271		*/
272	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
273	0	return 0;
274	0	}
275		/*
276		* If the command takes no input, there must be no input. And vice versa.
277		*/
278	0	if (flags & ENGINE_CMD_FLAG_NO_INPUT) {
279	0	if (arg != NULL) {
280	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_COMMAND_TAKES_NO_INPUT);
281	0	return 0;
282	0	}
283		/*
284		* We deliberately force the result of ENGINE_ctrl() to 0 or 1 rather
285		* than returning it as "return data". This is to ensure usage of
286		* these commands is consistent across applications and that certain
287		* applications don't understand it one way, and others another.
288		*/
289	0	if (ENGINE_ctrl(e, num, 0, (void *)arg, NULL) > 0)
290	0	return 1;
291	0	return 0;
292	0	}
293		/* So, we require input */
294	0	if (arg == NULL) {
295	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_COMMAND_TAKES_INPUT);
296	0	return 0;
297	0	}
298		/* If it takes string input, that's easy */
299	0	if (flags & ENGINE_CMD_FLAG_STRING) {
300		/* Same explanation as above */
301	0	if (ENGINE_ctrl(e, num, 0, (void *)arg, NULL) > 0)
302	0	return 1;
303	0	return 0;
304	0	}
305		/*
306		* If it doesn't take numeric either, then it is unsupported for use in a
307		* config-setting situation, which is what this function is for. This
308		* should never happen though, because ENGINE_cmd_is_executable() was
309		* used.
310		*/
311	0	if (!(flags & ENGINE_CMD_FLAG_NUMERIC)) {
312	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
313	0	return 0;
314	0	}
315	0	l = strtol(arg, &ptr, 10);
316	0	if ((arg == ptr) \|\| (*ptr != '\0')) {
317	0	ERR_raise(ERR_LIB_ENGINE, ENGINE_R_ARGUMENT_IS_NOT_A_NUMBER);
318	0	return 0;
319	0	}
320		/*
321		* Force the result of the control command to 0 or 1, for the reasons
322		* mentioned before.
323		*/
324	0	if (ENGINE_ctrl(e, num, l, NULL, NULL) > 0)
325	0	return 1;
326	0	return 0;
327	0	}