Function start_ifversion

modules/metadata/mod_version.c:172–296

* Implements the container */

 * Implements the <IfVersion> container
 */
static const char *start_ifversion(cmd_parms *cmd, void *mconfig,
                                   const char *arg1, const char *arg2,
                                   const char *arg3)
{
    const char *endp;
    int reverse = 0, done = 0, match = 0, compare;
    const char *p, *error;
    char c;

    /* supplying one argument is possible, we assume an equality check then */
    if (!arg2) {
        arg2 = arg1;
        arg1 = "=";
    }

    /* surrounding quotes without operator */
    if (!arg3 && *arg2 == '>' && !arg2[1]) {
        arg3 = ">";
        arg2 = arg1;
        arg1 = "=";
    }

    /* the third argument makes version surrounding quotes plus operator
     * possible.
     */
    endp = arg2 + strlen(arg2);
    if (   endp == arg2
        || (!(arg3 && *arg3 == '>' && !arg3[1]) && *--endp != '>')) {
        return apr_pstrcat(cmd->pool, cmd->cmd->name,
                           "> directive missing closing '>'", NULL);
    }

    p = arg1;
    if (*p == '!') {
        reverse = 1;
        if (p[1]) {
            ++p;
        }
    }

    c = *p++;
    if (!*p || (*p == '=' && !p[1] && c != '~')) {
        if (!httpd_version.major) {
            ap_get_server_revision(&httpd_version);
        }

        done = 1;
        switch (c) {
        case '=':
            /* normal comparison */
            if (*arg2 != '/') {
                compare = compare_version(apr_pstrmemdup(cmd->temp_pool, arg2,
                                                         endp-arg2),
                                          &error);
                if (error) {
                    return error;
                }