C function to parse a simple "command: value" line into command and value

configile.c

/*
 * written by kyle isom <[email protected]>
 * license: isc / public domain dual license
 * one of the functions i wrote for the lurker project
 * (https://github.com/kisom/lurker)
 *
 * C function to split a line into command and value
 */

/*
 * Internal function to split a line into command and value
 *     arguments:
 *         - line: a line of text. in lurker, this is already guaranteed
 *           to be an allocated buffer with a line of text in it, and it
 *           is guaranteed not to have any newlines or carriage returns. 
 *           if it is used elsewhere, it may need to be tweaked.
 *         - a pointer to a char pointer, this should be a char * in the 
 *           caller. this will be allocated with the proper amount of memory
 *           and needs to be freed by the caller. this is used to store the
 *           command.
 *         - a pointer to a char pointer, this should be a char * in the 
 *           caller. this will be allocated with the proper amount of memory
 *           and needs to be freed by the caller. this is used to store the
 *           value of the command.
 *         - a const char that contains the character used to demarcate command
 *           and value.
 *     returns:
 *         - EXIT_FAILURE on function failure (i.e. malloc error, or the
 *           line doesn't look like a command)
 *         - EXIT_SUCCESS if it looks like all went well
 *     cleaning up: pass cmd and val to destroy_simple(cmd, val) to properly free
 *     the memory.
 * 
 * an example line looks like "server: irc.example.net", cmd will have "server" 
 * and val will have "irc.example.net".
*/
int
parse_simple(char *line, char *cmd, char *val, const char split_char)
{
        char *cmdval;

        cmdval = strdup(line);
        if (NULL == cmdval)
            return EXIT_FAILURE;

        cmd = cmdval;
        val = strchr(cmdval, (int)split_char);
        if (0 == strlen(val)) {
            destroy_simple(cmd, val);
            return EXIT_FAILURE;
        }

        cmdval = NULL;
        val[0] = '\0';
        val++;

        return EXIT_SUCCESS;
}

void
destroy_simple(char *cmd, char *val)
{
        if ('\0' != val[0])
            (--val)[0] = 'A'; /* Pick a char, any char. */
        
        free(cmd);
        cmd = NULL;
        val = NULL;

        return;
}