request.c

Apache HTTP Server 是一个功能强大的灵活的与HTTP/1.1相兼容的web服务器.这里给出的是Apache HTTP服务器的源码。

                                                      now_merged,
                                                      sec_ent[sec_idx]);
            }
            else {
                now_merged = sec_ent[sec_idx];
            }

            last_walk = (walk_walked_t*)apr_array_push(cache->walked);
            last_walk->matched = sec_ent[sec_idx];
            last_walk->merged = now_merged;
        }

        /* Whoops - everything matched in sequence, but the original walk
         * found some additional matches.  Truncate them.
         */
        if (matches) {
            cache->walked->nelts -= matches;
        }
    }

/* It seems this shouldn't be needed anymore.  We translated the
 x symlink above into a real resource, and should have died up there.
 x Even if we keep this, it needs more thought (maybe an r->file_is_symlink)
 x perhaps it should actually happen in file_walk, so we catch more
 x obscure cases in autoindex subrequests, etc.
 x
 x    * Symlink permissions are determined by the parent.  If the request is
 x    * for a directory then applying the symlink test here would use the
 x    * permissions of the directory as opposed to its parent.  Consider a
 x    * symlink pointing to a dir with a .htaccess disallowing symlinks.  If
 x    * you access /symlink (or /symlink/) you would get a 403 without this
 x    * APR_DIR test.  But if you accessed /symlink/index.html, for example,
 x    * you would *not* get the 403.
 x
 x   if (r->finfo.filetype != APR_DIR
 x       && (res = resolve_symlink(r->filename, r->info, ap_allow_options(r),
 x                                 r->pool))) {
 x       ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 x                     "Symbolic link not allowed: %s", r->filename);
 x       return res;
 x   }
 */

    /* Save future sub-requestors much angst in processing
     * this subrequest.  If dir_walk couldn't canonicalize
     * the file path, nothing can.
     */
    r->canonical_filename = r->filename;

    if (r->finfo.filetype == APR_DIR) {
        cache->cached = r->filename;
    }
    else {
        cache->cached = ap_make_dirstr_parent(r->pool, r->filename);
    }

    cache->dir_conf_tested = sec_ent;
    cache->dir_conf_merged = r->per_dir_config;

    /* Merge our cache->dir_conf_merged construct with the r->per_dir_configs,
     * and note the end result to (potentially) skip this step next time.
     */
    if (now_merged) {
        r->per_dir_config = ap_merge_per_dir_configs(r->pool,
                                                     r->per_dir_config,
                                                     now_merged);
    }
    cache->per_dir_result = r->per_dir_config;

    return OK;
}


AP_DECLARE(int) ap_location_walk(request_rec *r)
{
    ap_conf_vector_t *now_merged = NULL;
    core_server_config *sconf = ap_get_module_config(r->server->module_config,
                                                     &core_module);
    ap_conf_vector_t **sec_ent = (ap_conf_vector_t **)sconf->sec_url->elts;
    int num_sec = sconf->sec_url->nelts;
    walk_cache_t *cache;
    const char *entry_uri;

    /* No tricks here, there are no <Locations > to parse in this vhost.
     * We won't destroy the cache, just in case _this_ redirect is later
     * redirected again to a vhost with <Location > blocks to optimize.
     */
    if (!num_sec) {
        return OK;
    }

    cache = prep_walk_cache(AP_NOTE_LOCATION_WALK, r);

    /* Location and LocationMatch differ on their behaviour w.r.t. multiple
     * slashes.  Location matches multiple slashes with a single slash,
     * LocationMatch doesn't.  An exception, for backwards brokenness is
     * absoluteURIs... in which case neither match multiple slashes.
     */
    if (r->uri[0] != '/') {
        entry_uri = r->uri;
    }
    else {
        char *uri = apr_pstrdup(r->pool, r->uri);
        ap_no2slash(uri);
        entry_uri = uri;
    }

    /* If we have an cache->cached location that matches r->uri,
     * and the vhost's list of locations hasn't changed, we can skip
     * rewalking the location_walk entries.
     */
    if (cache->cached
        && (cache->dir_conf_tested == sec_ent)
        && (strcmp(entry_uri, cache->cached) == 0)) {
        /* Well this looks really familiar!  If our end-result (per_dir_result)
         * didn't change, we have absolutely nothing to do :)
         * Otherwise (as is the case with most dir_merged/file_merged requests)
         * we must merge our dir_conf_merged onto this new r->per_dir_config.
         */
        if (r->per_dir_config == cache->per_dir_result) {
            return OK;
        }

        if (r->per_dir_config == cache->dir_conf_merged) {
            r->per_dir_config = cache->per_dir_result;
            return OK;
        }

        if (cache->walked->nelts) {
            now_merged = ((walk_walked_t*)cache->walked->elts)
                                            [cache->walked->nelts - 1].merged;
        }
    }
    else {
        /* We start now_merged from NULL since we want to build
         * a locations list that can be merged to any vhost.
         */
        int len, sec_idx;
        int matches = cache->walked->nelts;
        walk_walked_t *last_walk = (walk_walked_t*)cache->walked->elts;
        cache->cached = entry_uri;

        /* Go through the location entries, and check for matches.
         * We apply the directive sections in given order, we should
         * really try them with the most general first.
         */
        for (sec_idx = 0; sec_idx < num_sec; ++sec_idx) {

            core_dir_config *entry_core;
            entry_core = ap_get_module_config(sec_ent[sec_idx], &core_module);

            /* ### const strlen can be optimized in location config parsing */
            len = strlen(entry_core->d);

            /* Test the regex, fnmatch or string as appropriate.
             * If it's a strcmp, and the <Location > pattern was
             * not slash terminated, then this uri must be slash
             * terminated (or at the end of the string) to match.
             */
            if (entry_core->r
                ? ap_regexec(entry_core->r, r->uri, 0, NULL, 0)
                : (entry_core->d_is_fnmatch
                   ? apr_fnmatch(entry_core->d, cache->cached, FNM_PATHNAME)
                   : (strncmp(entry_core->d, cache->cached, len)
                      || (entry_core->d[len - 1] != '/'
                          && cache->cached[len] != '/'
                          && cache->cached[len] != '\0')))) {
                continue;
            }

            /* If we merged this same section last time, reuse it
             */
            if (matches) {
                if (last_walk->matched == sec_ent[sec_idx]) {
                    now_merged = last_walk->merged;
                    ++last_walk;
                    --matches;
                    continue;
                }

                /* We fell out of sync.  This is our own copy of walked,
                 * so truncate the remaining matches and reset remaining.
                 */
                cache->walked->nelts -= matches;
                matches = 0;
            }

            if (now_merged) {
                now_merged = ap_merge_per_dir_configs(r->pool,
                                                      now_merged,
                                                      sec_ent[sec_idx]);
            }
            else {
                now_merged = sec_ent[sec_idx];
            }

            last_walk = (walk_walked_t*)apr_array_push(cache->walked);
            last_walk->matched = sec_ent[sec_idx];
            last_walk->merged = now_merged;
        }

        /* Whoops - everything matched in sequence, but the original walk
         * found some additional matches.  Truncate them.
         */
        if (matches) {
            cache->walked->nelts -= matches;
        }
    }

    cache->dir_conf_tested = sec_ent;
    cache->dir_conf_merged = r->per_dir_config;

    /* Merge our cache->dir_conf_merged construct with the r->per_dir_configs,
     * and note the end result to (potentially) skip this step next time.
     */
    if (now_merged) {
        r->per_dir_config = ap_merge_per_dir_configs(r->pool,
                                                     r->per_dir_config,
                                                     now_merged);
    }
    cache->per_dir_result = r->per_dir_config;

    return OK;
}

AP_DECLARE(int) ap_file_walk(request_rec *r)
{
    ap_conf_vector_t *now_merged = NULL;
    core_dir_config *dconf = ap_get_module_config(r->per_dir_config,
                                                  &core_module);
    ap_conf_vector_t **sec_ent = (ap_conf_vector_t **)dconf->sec_file->elts;
    int num_sec = dconf->sec_file->nelts;
    walk_cache_t *cache;
    const char *test_file;

    /* To allow broken modules to proceed, we allow missing filenames to pass.
     * We will catch it later if it's heading for the core handler.
     * directory_walk already posted an INFO note for module debugging.
     */
    if (r->filename == NULL) {
        return OK;
    }

    cache = prep_walk_cache(AP_NOTE_FILE_WALK, r);

    /* No tricks here, there are just no <Files > to parse in this context.
     * We won't destroy the cache, just in case _this_ redirect is later
     * redirected again to a context containing the same or similar <Files >.
     */
    if (!num_sec) {
        return OK;
    }

    /* Get the basename .. and copy for the cache just
     * in case r->filename is munged by another module
     */
    test_file = strrchr(r->filename, '/');
    if (test_file == NULL) {
        test_file = apr_pstrdup(r->pool, r->filename);
    }
    else {
        test_file = apr_pstrdup(r->pool, ++test_file);
    }

    /* If we have an cache->cached file name that matches test_file,
     * and the directory's list of file sections hasn't changed, we
     * can skip rewalking the file_walk entries.
     */
    if (cache->cached
        && (cache->dir_conf_tested == sec_ent)
        && (strcmp(test_file, cache->cached) == 0)) {
        /* Well this looks really familiar!  If our end-result (per_dir_result)
         * didn't change, we have absolutely nothing to do :)
         * Otherwise (as is the case with most dir_merged requests)
         * we must merge our dir_conf_merged onto this new r->per_dir_config.
         */
        if (r->per_dir_config == cache->per_dir_result) {
            return OK;
        }

        if (r->per_dir_config == cache->dir_conf_merged) {
            r->per_dir_config = cache->per_dir_result;
            return OK;
        }

        if (cache->walked->nelts) {
            now_merged = ((walk_walked_t*)cache->walked->elts)
                [cache->walked->nelts - 1].merged;
        }
    }
    else {
        /* We start now_merged from NULL since we want to build
         * a file section list that can be merged to any dir_walk.
         */
        int sec_idx;
        int matches = cache->walked->nelts;
        walk_walked_t *last_walk = (walk_walked_t*)cache->walked->elts;
        cache->cached = test_file;

        /* Go through the location entries, and check for matches.
         * We apply the directive sections in given order, we should
         * really try them with the most general first.
         */
        for (sec_idx = 0; sec_idx < num_sec; ++sec_idx) {

            core_dir_config *entry_core;
            entry_core = ap_get_module_config(sec_ent[sec_idx], &core_module);

            if (entry_core->r
                ? ap_regexec(entry_core->r, cache->cached , 0, NULL, 0)
                : (entry_core->d_is_fnmatch
                   ? apr_fnmatch(entry_core->d, cache->cached, FNM_PATHNAME)
                   : strcmp(entry_core->d, cache->cached))) {
                continue;
            }

            /* If we merged this same section last time, reuse it
             */
            if (matches) {
                if (last_walk->matched == sec_ent[sec_idx]) {
                    now_merged = last_walk->merged;
                    ++last_walk;
                    --matches;
                    continue;
                }

                /* We fell out of sync.  This is our own copy of walked,
                 * so truncate the remaining matches and reset remaining.
                 */
                cache->walked->nelts -= matches;
                matches = 0;
            }

            if (now_merged) {
                now_merged = ap_merge_per_dir_configs(r->pool,
                                                      now_merged,
                                                      sec_ent[sec_idx]);
            }
            else {
                now_merged = sec_ent[sec_idx];
            }

            last_walk = (walk_walked_t*)apr_array_push(cache->walked);
            last_walk->matched = sec_ent[sec_idx];
            last_walk->merged = now_merged;
        }

        /* Whoops - everything matched in sequence, but the original walk
         * found some additional matches.  Truncate them.
         */
        if (matches) {
            cache->walked->nelts -= matches;
        }
    }

    cache->dir_conf_tested = sec_ent;
    cache->dir_conf_merged = r->per_dir_config;