mod_rewrite.c

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

                    ctx->r = r;
                    ap_destroy_sub_req(rr);

                    rewritelog((r, 5, ctx->perdir, "lookahead: path=%s var=%s "
                                "-> val=%s", path, var+5, result));

                    return (char *)result;
                }
            }
        }
    }

    /* well, do it the hard way */
    else {
        char *p;
        apr_time_exp_t tm;

        /* can't do this above, because of the getenv call */
        for (p = var; *p; ++p) {
            *p = apr_toupper(*p);
        }

        switch (varlen) {
        case  4:
            if (!strcmp(var, "TIME")) {
                apr_time_exp_lt(&tm, apr_time_now());
                result = apr_psprintf(r->pool, "%04d%02d%02d%02d%02d%02d",
                                      tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
                                      tm.tm_hour, tm.tm_min, tm.tm_sec);
                rewritelog((r, 1, ctx->perdir, "RESULT='%s'", result));
                return (char *)result;
            }
            break;

        case  5:
            if (!strcmp(var, "HTTPS")) {
                int flag = rewrite_is_https && rewrite_is_https(r->connection);
                return apr_pstrdup(r->pool, flag ? "on" : "off");
            }
            break;

        case  8:
            switch (var[6]) {
            case 'A':
                if (!strcmp(var, "TIME_DAY")) {
                    apr_time_exp_lt(&tm, apr_time_now());
                    return apr_psprintf(r->pool, "%02d", tm.tm_mday);
                }
                break;

            case 'E':
                if (!strcmp(var, "TIME_SEC")) {
                    apr_time_exp_lt(&tm, apr_time_now());
                    return apr_psprintf(r->pool, "%02d", tm.tm_sec);
                }
                break;

            case 'I':
                if (!strcmp(var, "TIME_MIN")) {
                    apr_time_exp_lt(&tm, apr_time_now());
                    return apr_psprintf(r->pool, "%02d", tm.tm_min);
                }
                break;

            case 'O':
                if (!strcmp(var, "TIME_MON")) {
                    apr_time_exp_lt(&tm, apr_time_now());
                    return apr_psprintf(r->pool, "%02d", tm.tm_mon+1);
                }
                break;
            }
            break;

        case  9:
            switch (var[7]) {
            case 'A':
                if (var[8] == 'Y' && !strcmp(var, "TIME_WDAY")) {
                    apr_time_exp_lt(&tm, apr_time_now());
                    return apr_psprintf(r->pool, "%d", tm.tm_wday);
                }
                else if (!strcmp(var, "TIME_YEAR")) {
                    apr_time_exp_lt(&tm, apr_time_now());
                    return apr_psprintf(r->pool, "%04d", tm.tm_year+1900);
                }
                break;

            case 'E':
                if (!strcmp(var, "IS_SUBREQ")) {
                    result = (r->main ? "true" : "false");
                }
                break;

            case 'F':
                if (!strcmp(var, "PATH_INFO")) {
                    result = r->path_info;
                }
                break;

            case 'P':
                if (!strcmp(var, "AUTH_TYPE")) {
                    result = r->ap_auth_type;
                }
                break;

            case 'S':
                if (!strcmp(var, "HTTP_HOST")) {
                    result = lookup_header("Host", ctx);
                }
                break;

            case 'U':
                if (!strcmp(var, "TIME_HOUR")) {
                    apr_time_exp_lt(&tm, apr_time_now());
                    return apr_psprintf(r->pool, "%02d", tm.tm_hour);
                }
                break;
            }
            break;

        case 11:
            switch (var[8]) {
            case 'A':
                if (!strcmp(var, "SERVER_NAME")) {
                    result = ap_get_server_name(r);
                }
                break;

            case 'D':
                if (*var == 'R' && !strcmp(var, "REMOTE_ADDR")) {
                    result = r->connection->remote_ip;
                }
                else if (!strcmp(var, "SERVER_ADDR")) {
                    result = r->connection->local_ip;
                }
                break;

            case 'E':
                if (*var == 'H' && !strcmp(var, "HTTP_ACCEPT")) {
                    result = lookup_header("Accept", ctx);
                }
                else if (!strcmp(var, "THE_REQUEST")) {
                    result = r->the_request;
                }
                break;

            case 'I':
                if (!strcmp(var, "API_VERSION")) {
                    return apr_psprintf(r->pool, "%d:%d",
                                        MODULE_MAGIC_NUMBER_MAJOR,
                                        MODULE_MAGIC_NUMBER_MINOR);
                }
                break;

            case 'K':
                if (!strcmp(var, "HTTP_COOKIE")) {
                    result = lookup_header("Cookie", ctx);
                }
                break;

            case 'O':
                if (*var == 'S' && !strcmp(var, "SERVER_PORT")) {
                    return apr_psprintf(r->pool, "%u", ap_get_server_port(r));
                }
                else if (var[7] == 'H' && !strcmp(var, "REMOTE_HOST")) {
                    result = ap_get_remote_host(r->connection,r->per_dir_config,
                                                REMOTE_NAME, NULL);
                }
                else if (!strcmp(var, "REMOTE_PORT")) {
                    return apr_itoa(r->pool, r->connection->remote_addr->port);
                }
                break;

            case 'S':
                if (*var == 'R' && !strcmp(var, "REMOTE_USER")) {
                    result = r->user;
                }
                else if (!strcmp(var, "SCRIPT_USER")) {
                    result = "<unknown>";
                    if (r->finfo.valid & APR_FINFO_USER) {
                        apr_uid_name_get((char **)&result, r->finfo.user,
                                         r->pool);
                    }
                }
                break;

            case 'U':
                if (!strcmp(var, "REQUEST_URI")) {
                    result = r->uri;
                }
                break;
            }
            break;

        case 12:
            switch (var[3]) {
            case 'I':
                if (!strcmp(var, "SCRIPT_GROUP")) {
                    result = "<unknown>";
                    if (r->finfo.valid & APR_FINFO_GROUP) {
                        apr_gid_name_get((char **)&result, r->finfo.group,
                                         r->pool);
                    }
                }
                break;

            case 'O':
                if (!strcmp(var, "REMOTE_IDENT")) {
                    result = ap_get_remote_logname(r);
                }
                break;

            case 'P':
                if (!strcmp(var, "HTTP_REFERER")) {
                    result = lookup_header("Referer", ctx);
                }
                break;

            case 'R':
                if (!strcmp(var, "QUERY_STRING")) {
                    result = r->args;
                }
                break;

            case 'V':
                if (!strcmp(var, "SERVER_ADMIN")) {
                    result = r->server->server_admin;
                }
                break;
            }
            break;

        case 13:
            if (!strcmp(var, "DOCUMENT_ROOT")) {
                result = ap_document_root(r);
            }
            break;

        case 14:
            if (*var == 'H' && !strcmp(var, "HTTP_FORWARDED")) {
                result = lookup_header("Forwarded", ctx);
            }
            else if (!strcmp(var, "REQUEST_METHOD")) {
                result = r->method;
            }
            break;

        case 15:
            switch (var[7]) {
            case 'E':
                if (!strcmp(var, "HTTP_USER_AGENT")) {
                    result = lookup_header("User-Agent", ctx);
                }
                break;

            case 'F':
                if (!strcmp(var, "SCRIPT_FILENAME")) {
                    result = r->filename; /* same as request_filename (16) */
                }
                break;

            case 'P':
                if (!strcmp(var, "SERVER_PROTOCOL")) {
                    result = r->protocol;
                }
                break;

            case 'S':
                if (!strcmp(var, "SERVER_SOFTWARE")) {
                    result = ap_get_server_banner();
                }
                break;
            }
            break;

        case 16:
            if (!strcmp(var, "REQUEST_FILENAME")) {
                result = r->filename; /* same as script_filename (15) */
            }
            break;

        case 21:
            if (!strcmp(var, "HTTP_PROXY_CONNECTION")) {
                result = lookup_header("Proxy-Connection", ctx);
            }
            break;
        }
    }

    return apr_pstrdup(r->pool, result ? result : "");
}


/*
 * +-------------------------------------------------------+
 * |                                                       |
 * |                 Expansion functions
 * |                                                       |
 * +-------------------------------------------------------+
 */

/*
 * Bracketed expression handling
 * s points after the opening bracket
 */
static APR_INLINE char *find_closing_curly(char *s)
{
    unsigned depth;

    for (depth = 1; *s; ++s) {
        if (*s == RIGHT_CURLY && --depth == 0) {
            return s;
        }
        else if (*s == LEFT_CURLY) {
            ++depth;
        }
    }

    return NULL;
}

static APR_INLINE char *find_char_in_curlies(char *s, int c)
{
    unsigned depth;

    for (depth = 1; *s; ++s) {
        if (*s == c && depth == 1) {
            return s;
        }
        else if (*s == RIGHT_CURLY && --depth == 0) {
            return NULL;
        }
        else if (*s == LEFT_CURLY) {
            ++depth;
        }
    }

    return NULL;
}

/* perform all the expansions on the input string
 * putting the result into a new string
 *
 * for security reasons this expansion must be performed in a
 * single pass, otherwise an attacker can arrange for the result
 * of an earlier expansion to include expansion specifiers that
 * are interpreted by a later expansion, producing results that
 * were not intended by the administrator.
 */
static char *do_expand(char *input, rewrite_ctx *ctx, rewriterule_entry *entry)
{
    result_list *result, *current;
    result_list sresult[SMALL_EXPANSION];
    unsigned spc = 0;
    apr_size_t span, inputlen, outlen;
    char *p, *c;
    apr_pool_t *pool = ctx->r->pool;

    span = strcspn(input, "\\$%");
    inputlen = strlen(input);

    /* fast exit */
    if (inputlen == span) {
        return apr_pstrdup(pool, input);
    }

    /* well, actually something to do */
    result = current = &(sresult[spc++]);

    p = input + span;
    current->next = NULL;
    current->string = input;
    current->len = span;
    outlen = span;

    /* loop for specials */
    do {
        /* prepare next entry */
        if (current->len) {
            current->next = (spc < SMALL_EXPANSION)
                            ? &(sresult[spc++])
                            : (result_list *)apr_palloc(pool,
                                                        sizeof(result_list));
            current = current->next;
            current->next = NULL;
            current->len = 0;
        }

        /* escaped character */
        if (*p == '\\') {
            current->len = 1;
            ++outlen;
            if (!p[1]) {
                current->string = p;
                break;
            }
            else {
                current->string = ++p;
                ++p;
            }
        }

        /* variable or map lookup */
        else if (p[1] == '{') {
            char *endp;

            endp = find_closing_curly(p+2);
            if (!endp) {
                current->len = 2;
                current->string = p;
                outlen += 2;
                p += 2;
            }

            /* variable lookup */
            else if (*p == '%') {
                p = lookup_variable(apr_pstrmemdup(pool, p+2, endp-p-2), ctx);

                span = strlen(p);
                current->len = span;
                current->string = p;
                outlen += span;
                p = endp + 1;
            }

            /* map lookup */
            else {     /* *p == '$' */
                char *key;

                /*
                 * To make rewrite maps useful, the lookup key and
                 * default values must be expanded, so we make
                 * recursive calls to do the work. For security
                 * reasons we must never expand a string that includes
                 * verbatim da