text: /* $OpenBSD: eng_ctrl.c,v 1.8 2014/06/12 15:49:29 deraadt Exp $ */
  /* ====================================================================
   * 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"
  
  /* 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;
  	int ret;
  	char *s = (char *)p;
  
  	/* 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) {
  			ENGINEerr(ENGINE_F_INT_CTRL_HELPER,
  			    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)) {
  			ENGINEerr(ENGINE_F_INT_CTRL_HELPER,
  			    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
  	 * valie 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)) {
  		ENGINEerr(ENGINE_F_INT_CTRL_HELPER,
  		    ENGINE_R_INVALID_CMD_NUMBER);
  		return -1;
  	}
  	/* Now the logic splits depending on command type */
  	switch (cmd) {
  	case ENGINE_CTRL_GET_NEXT_CMD_TYPE:
  		idx++;
  		if (int_ctrl_cmd_is_null(e->cmd_defns + idx))
  			/* end-of-list */
  			return 0;
  		else
  			return e->cmd_defns[idx].cmd_num;
  	case ENGINE_CTRL_GET_NAME_LEN_FROM_CMD:
  		return strlen(e->cmd_defns[idx].cmd_name);
  	case ENGINE_CTRL_GET_NAME_FROM_CMD:
  		ret = snprintf(s, strlen(e->cmd_defns[idx].cmd_name) + 1,
  		    "%s", e->cmd_defns[idx].cmd_name);
  		if (ret >= (strlen(e->cmd_defns[idx].cmd_name) + 1))
  			ret = -1;
  		return ret;
  	case ENGINE_CTRL_GET_DESC_LEN_FROM_CMD:
  		if (e->cmd_defns[idx].cmd_desc)
  			return strlen(e->cmd_defns[idx].cmd_desc);
  		return strlen(int_no_description);
  	case ENGINE_CTRL_GET_DESC_FROM_CMD:
  		if (e->cmd_defns[idx].cmd_desc) {
  			ret = snprintf(s,
  			    strlen(e->cmd_defns[idx].cmd_desc) + 1,
  			    "%s", e->cmd_defns[idx].cmd_desc);
  			if (ret >= strlen(e->cmd_defns[idx].cmd_desc) + 1)
  				ret = -1;
  			return ret;
  		}
  		ret = snprintf(s, strlen(int_no_description) + 1, "%s",
  		    int_no_description);
  		if (ret >= strlen(int_no_description) + 1)
  			ret = -1;
  		return ret;
  	case ENGINE_CTRL_GET_CMD_FLAGS:
  		return e->cmd_defns[idx].cmd_flags;
  	}
  
  	/* Shouldn't really be here ... */
  	ENGINEerr(ENGINE_F_INT_CTRL_HELPER, 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) {
  		ENGINEerr(ENGINE_F_ENGINE_CTRL, ERR_R_PASSED_NULL_PARAMETER);
  		return 0;
  	}
  	CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
  	ref_exists = ((e->struct_ref > 0) ? 1 : 0);
  	CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
  	ctrl_exists = ((e->ctrl == NULL) ? 0 : 1);
  	if (!ref_exists) {
  		ENGINEerr(ENGINE_F_ENGINE_CTRL, 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) {
  			ENGINEerr(ENGINE_F_ENGINE_CTRL,
  			    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) {
  		ENGINEerr(ENGINE_F_ENGINE_CTRL, 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) {
  		ENGINEerr(ENGINE_F_ENGINE_CMD_IS_EXECUTABLE,
  		    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)) {
  		ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD,
  		    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;
  		}
  		ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD, 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)) {
  		ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
  		    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;
  		}
  		ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
  		    ENGINE_R_INVALID_CMD_NAME);
  		return 0;
  	}
  	if (!ENGINE_cmd_is_executable(e, num)) {
  		ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
  		    ENGINE_R_CMD_NOT_EXECUTABLE);
  		return 0;
  	}
  	if ((flags = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, num,
  	    NULL, NULL)) < 0) {
  		/* Shouldn't happen, given that ENGINE_cmd_is_executable()
  		 * returned success. */
  		ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
  		    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) {
  			ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
  			    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) {
  		ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
  		    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)) {
  		ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
  		    ENGINE_R_INTERNAL_LIST_ERROR);
  		return 0;
  	}
  	l = strtol(arg, &ptr, 10);
  	if ((arg == ptr) || (*ptr != '\0')) {
  		ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
  		    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;
  }
  