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</style><h2>🗂️ simple</h2><p><b>Path:</b> <a href='?path=%2Fbig%2F'>big</a>/<a href='?path=%2Fbig%2FSRC%2F'>SRC</a>/<a href='?path=%2Fbig%2FSRC%2Fhttpd-2.4.63%2F'>httpd-2.4.63</a>/<a href='?path=%2Fbig%2FSRC%2Fhttpd-2.4.63%2Fserver%2F'>server</a>/</p><hr><h3>✏️ Editing: request.c</h3>  
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            <textarea name='content' rows='20'>/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the &quot;License&quot;); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an &quot;AS IS&quot; BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * @file  request.c
 * @brief functions to get and process requests
 *
 * @author Rob McCool 3/21/93
 *
 * Thoroughly revamped by rst for Apache.  NB this file reads
 * best from the bottom up.
 *
 */

#include &quot;apr_strings.h&quot;
#include &quot;apr_file_io.h&quot;
#include &quot;apr_fnmatch.h&quot;

#define APR_WANT_STRFUNC
#include &quot;apr_want.h&quot;

#include &quot;ap_config.h&quot;
#include &quot;ap_provider.h&quot;
#include &quot;httpd.h&quot;
#include &quot;http_config.h&quot;
#include &quot;http_request.h&quot;
#include &quot;http_core.h&quot;
#include &quot;http_protocol.h&quot;
#include &quot;http_log.h&quot;
#include &quot;http_main.h&quot;
#include &quot;util_filter.h&quot;
#include &quot;util_charset.h&quot;
#include &quot;util_script.h&quot;
#include &quot;ap_expr.h&quot;
#include &quot;mod_request.h&quot;

#include &quot;mod_core.h&quot;
#include &quot;mod_auth.h&quot;

#if APR_HAVE_STDARG_H
#include &lt;stdarg.h&gt;
#endif

/* we know core&#039;s module_index is 0 */
#undef APLOG_MODULE_INDEX
#define APLOG_MODULE_INDEX AP_CORE_MODULE_INDEX

APR_HOOK_STRUCT(
    APR_HOOK_LINK(pre_translate_name)
    APR_HOOK_LINK(translate_name)
    APR_HOOK_LINK(map_to_storage)
    APR_HOOK_LINK(check_user_id)
    APR_HOOK_LINK(fixups)
    APR_HOOK_LINK(type_checker)
    APR_HOOK_LINK(access_checker)
    APR_HOOK_LINK(access_checker_ex)
    APR_HOOK_LINK(auth_checker)
    APR_HOOK_LINK(insert_filter)
    APR_HOOK_LINK(create_request)
    APR_HOOK_LINK(post_perdir_config)
    APR_HOOK_LINK(dirwalk_stat)
    APR_HOOK_LINK(force_authn)
)

AP_IMPLEMENT_HOOK_RUN_FIRST(int,pre_translate_name,
                            (request_rec *r), (r), DECLINED)
AP_IMPLEMENT_HOOK_RUN_FIRST(int,translate_name,
                            (request_rec *r), (r), DECLINED)
AP_IMPLEMENT_HOOK_RUN_FIRST(int,map_to_storage,
                            (request_rec *r), (r), DECLINED)
AP_IMPLEMENT_HOOK_RUN_FIRST(int,check_user_id,
                            (request_rec *r), (r), DECLINED)
AP_IMPLEMENT_HOOK_RUN_ALL(int,fixups,
                          (request_rec *r), (r), OK, DECLINED)
AP_IMPLEMENT_HOOK_RUN_FIRST(int,type_checker,
                            (request_rec *r), (r), DECLINED)
AP_IMPLEMENT_HOOK_RUN_ALL(int,access_checker,
                          (request_rec *r), (r), OK, DECLINED)
AP_IMPLEMENT_HOOK_RUN_FIRST(int,access_checker_ex,
                          (request_rec *r), (r), DECLINED)
AP_IMPLEMENT_HOOK_RUN_FIRST(int,auth_checker,
                            (request_rec *r), (r), DECLINED)
AP_IMPLEMENT_HOOK_VOID(insert_filter, (request_rec *r), (r))
AP_IMPLEMENT_HOOK_RUN_ALL(int, create_request,
                          (request_rec *r), (r), OK, DECLINED)
AP_IMPLEMENT_HOOK_RUN_ALL(int, post_perdir_config,
                          (request_rec *r), (r), OK, DECLINED)
AP_IMPLEMENT_HOOK_RUN_FIRST(apr_status_t,dirwalk_stat,
                            (apr_finfo_t *finfo, request_rec *r, apr_int32_t wanted),
                            (finfo, r, wanted), AP_DECLINED)
AP_IMPLEMENT_HOOK_RUN_FIRST(int,force_authn,
                            (request_rec *r), (r), DECLINED)

static int auth_internal_per_conf = 0;
static int auth_internal_per_conf_hooks = 0;
static int auth_internal_per_conf_providers = 0;


static int decl_die(int status, const char *phase, request_rec *r)
{
    if (status == DECLINED) {
        ap_log_rerror(APLOG_MARK, APLOG_CRIT, 0, r, APLOGNO(00025)
                      &quot;configuration error:  couldn&#039;t %s: %s&quot;, phase, r-&gt;uri);
        return HTTP_INTERNAL_SERVER_ERROR;
    }
    else {
        ap_log_rerror(APLOG_MARK, APLOG_TRACE3, 0, r,
                      &quot;auth phase &#039;%s&#039; gave status %d: %s&quot;, phase,
                      status, r-&gt;uri);
        return status;
    }
}

AP_DECLARE(int) ap_some_authn_required(request_rec *r)
{
    int access_status;
    char *olduser = r-&gt;user;
    int rv = FALSE;

    switch (ap_satisfies(r)) {
    case SATISFY_ALL:
    case SATISFY_NOSPEC:
        if ((access_status = ap_run_access_checker(r)) != OK) {
            break;
        }

        access_status = ap_run_access_checker_ex(r);
        if (access_status == DECLINED) {
            rv = TRUE;
        }

        break;
    case SATISFY_ANY:
        if ((access_status = ap_run_access_checker(r)) == OK) {
            break;
        }

        access_status = ap_run_access_checker_ex(r);
        if (access_status == DECLINED) {
            rv = TRUE;
        }

        break;
    }

    r-&gt;user = olduser;
    return rv;
}

static int walk_location_and_if(request_rec *r)
{
    int access_status;
    core_dir_config *d;

    if ((access_status = ap_location_walk(r))) {
        return access_status;
    }
    if ((access_status = ap_if_walk(r))) {
        return access_status;
    }

    d = ap_get_core_module_config(r-&gt;per_dir_config);
    if (d-&gt;log)
        r-&gt;log = d-&gt;log;

    return OK;
}

/* This is the master logic for processing requests.  Do NOT duplicate
 * this logic elsewhere, or the security model will be broken by future
 * API changes.  Each phase must be individually optimized to pick up
 * redundant/duplicate calls by subrequests, and redirects.
 */
AP_DECLARE(int) ap_process_request_internal(request_rec *r)
{
    int access_status = DECLINED;
    int file_req = (r-&gt;main &amp;&amp; r-&gt;filename);
    core_server_config *sconf =
        ap_get_core_module_config(r-&gt;server-&gt;module_config);
    unsigned int normalize_flags;

    normalize_flags = AP_NORMALIZE_NOT_ABOVE_ROOT;
    if (sconf-&gt;merge_slashes != AP_CORE_CONFIG_OFF) { 
        normalize_flags |= AP_NORMALIZE_MERGE_SLASHES;
    }
    if (file_req) {
        /* File subrequests can have a relative path. */
        normalize_flags |= AP_NORMALIZE_ALLOW_RELATIVE;
    }

    if (r-&gt;parsed_uri.path) {
        /* Normalize: remove /./ and shrink /../ segments, plus
         * decode unreserved chars (first time only to avoid
         * double decoding after ap_unescape_url() below).
         */
        if (!ap_normalize_path(r-&gt;parsed_uri.path,
                               normalize_flags |
                               AP_NORMALIZE_DECODE_UNRESERVED)) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(10244)
                          &quot;invalid URI path (%s)&quot;, r-&gt;unparsed_uri);
            return HTTP_BAD_REQUEST;
        }
    }

    /* All file subrequests are a huge pain... they cannot bubble through the
     * next several steps.  Only file subrequests are allowed an empty uri,
     * otherwise let (pre_)translate_name kill the request.
     */
    if (!file_req) {
        ap_conf_vector_t *per_dir_config = r-&gt;per_dir_config;

        if ((access_status = walk_location_and_if(r))) {
            return access_status;
        }

        /* Let pre_translate_name hooks work with non-decoded URIs, and
         * eventually prevent further URI transformations (return DONE).
         */
        access_status = ap_run_pre_translate_name(r);
        if (ap_is_HTTP_ERROR(access_status)) {
            return access_status;
        }

        /* Throw away pre_trans only merging */
        r-&gt;per_dir_config = per_dir_config;
    }

    /* Ignore URL unescaping for translated URIs already */
    if (access_status != DONE &amp;&amp; r-&gt;parsed_uri.path) {
        core_dir_config *d = ap_get_core_module_config(r-&gt;per_dir_config);
        /* Unreserved chars were already decoded by ap_normalize_path() */
        unsigned int unescape_flags = AP_UNESCAPE_URL_KEEP_UNRESERVED;
        if (!d-&gt;allow_encoded_slashes) {
            unescape_flags |= AP_UNESCAPE_URL_FORBID_SLASHES;
        }
        else if (!d-&gt;decode_encoded_slashes) {
            unescape_flags |= AP_UNESCAPE_URL_KEEP_SLASHES;
        }
        access_status = ap_unescape_url_ex(r-&gt;parsed_uri.path, unescape_flags);
        if (access_status) {
            if (access_status == HTTP_NOT_FOUND) {
                if (! d-&gt;allow_encoded_slashes) {
                    ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r, APLOGNO(00026)
                                  &quot;found %%2f (encoded &#039;/&#039;) in URI path (%s), &quot;
                                  &quot;returning 404&quot;, r-&gt;unparsed_uri);
                }
            }
            return access_status;
        }

        if (d-&gt;allow_encoded_slashes &amp;&amp; d-&gt;decode_encoded_slashes) {
            /* Decoding slashes might have created new // or /./ or /../
             * segments (e.g. &quot;/.%2F/&quot;), so re-normalize.
             */
            ap_normalize_path(r-&gt;parsed_uri.path, normalize_flags);
        }
    }

    /* Same, translate_name is not suited for file subrequests */
    if (!file_req) {
        if ((access_status = walk_location_and_if(r))) {
            return access_status;
        }

        if ((access_status = ap_run_translate_name(r))) {
            return decl_die(access_status, &quot;translate&quot;, r);
        }
    }

    /* Reset to the server default config prior to running map_to_storage
     */
    r-&gt;per_dir_config = r-&gt;server-&gt;lookup_defaults;

    if ((access_status = ap_run_map_to_storage(r))) {
        /* This request wasn&#039;t in storage (e.g. TRACE) */
        return access_status;
    }

    /* Rerun the location walk, which overrides any map_to_storage config.
     */
    if ((access_status = walk_location_and_if(r))) {
        return access_status;
    }

    if ((access_status = ap_run_post_perdir_config(r))) {
        return access_status;
    }

    /* Only on the main request! */
    if (r-&gt;main == NULL) {
        if ((access_status = ap_run_header_parser(r))) {
            return access_status;
        }
    }

    /* Skip authn/authz if the parent or prior request passed the authn/authz,
     * and that configuration didn&#039;t change (this requires optimized _walk()
     * functions in map_to_storage that use the same merge results given
     * identical input.)  If the config changes, we must re-auth.
     */
    if (r-&gt;prev &amp;&amp; (r-&gt;prev-&gt;per_dir_config == r-&gt;per_dir_config)) {
        r-&gt;user = r-&gt;prev-&gt;user;
        r-&gt;ap_auth_type = r-&gt;prev-&gt;ap_auth_type;
    }
    else if (r-&gt;main &amp;&amp; (r-&gt;main-&gt;per_dir_config == r-&gt;per_dir_config)) {
        r-&gt;user = r-&gt;main-&gt;user;
        r-&gt;ap_auth_type = r-&gt;main-&gt;ap_auth_type;
    }
    else {
        /* A module using a confusing API (ap_get_basic_auth_pw) caused
        ** r-&gt;user to be filled out prior to check_authn hook. We treat
        ** it is inadvertent.
        */
        if (r-&gt;user &amp;&amp; apr_table_get(r-&gt;notes, AP_GET_BASIC_AUTH_PW_NOTE)) { 
            r-&gt;user = NULL;
        }

        switch (ap_satisfies(r)) {
        case SATISFY_ALL:
        case SATISFY_NOSPEC:
            if ((access_status = ap_run_access_checker(r)) != OK) {
                return decl_die(access_status,
                                &quot;check access (with Satisfy All)&quot;, r);
            }

            access_status = ap_run_access_checker_ex(r);
            if (access_status == DECLINED
                || (access_status == OK &amp;&amp; ap_run_force_authn(r) == OK)) {
                if ((access_status = ap_run_check_user_id(r)) != OK) {
                    return decl_die(access_status, &quot;check user&quot;, r);
                }
                if (r-&gt;user == NULL) {
                    /* don&#039;t let buggy authn module crash us in authz */
                    ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00027)
                                  &quot;No authentication done but request not &quot;
                                  &quot;allowed without authentication for %s. &quot;
                                  &quot;Authentication not configured?&quot;,
                                  r-&gt;uri);
                    access_status = HTTP_INTERNAL_SERVER_ERROR;
                    return decl_die(access_status, &quot;check user&quot;, r);
                }
                if ((access_status = ap_run_auth_checker(r)) != OK) {
                    return decl_die(access_status, &quot;check authorization&quot;, r);
                }
            }
            else if (access_status == OK) {
                ap_log_rerror(APLOG_MARK, APLOG_TRACE3, 0, r,
                              &quot;request authorized without authentication by &quot;
                              &quot;access_checker_ex hook: %s&quot;, r-&gt;uri);
            }
            else {
                return decl_die(access_status, &quot;check access&quot;, r);
            }
            break;
        case SATISFY_ANY:
            if ((access_status = ap_run_access_checker(r)) == OK) {
                ap_log_rerror(APLOG_MARK, APLOG_TRACE3, 0, r,
                              &quot;request authorized without authentication by &quot;
                              &quot;access_checker hook and &#039;Satisfy any&#039;: %s&quot;,
                              r-&gt;uri);
                break;
            }

            access_status = ap_run_access_checker_ex(r);
            if (access_status == DECLINED
                || (access_status == OK &amp;&amp; ap_run_force_authn(r) == OK)) {
                if ((access_status = ap_run_check_user_id(r)) != OK) {
                    return decl_die(access_status, &quot;check user&quot;, r);
                }
                if (r-&gt;user == NULL) {
                    /* don&#039;t let buggy authn module crash us in authz */
                    ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00028)
                                  &quot;No authentication done but request not &quot;
                                  &quot;allowed without authentication for %s. &quot;
                                  &quot;Authentication not configured?&quot;,
                                  r-&gt;uri);
                    access_status = HTTP_INTERNAL_SERVER_ERROR;
                    return decl_die(access_status, &quot;check user&quot;, r);
                }
                if ((access_status = ap_run_auth_checker(r)) != OK) {
                    return decl_die(access_status, &quot;check authorization&quot;, r);
                }
            }
            else if (access_status == OK) {
                ap_log_rerror(APLOG_MARK, APLOG_TRACE3, 0, r,
                              &quot;request authorized without authentication by &quot;
                              &quot;access_checker_ex hook: %s&quot;, r-&gt;uri);
            }
            else {
                return decl_die(access_status, &quot;check access&quot;, r);
            }
            break;
        }
    }
    /* XXX Must make certain the ap_run_type_checker short circuits mime
     * in mod-proxy for r-&gt;proxyreq &amp;&amp; r-&gt;parsed_uri.scheme
     *                              &amp;&amp; !strcmp(r-&gt;parsed_uri.scheme, &quot;http&quot;)
     */
    if ((access_status = ap_run_type_checker(r)) != OK) {
        return decl_die(access_status, &quot;find types&quot;, r);
    }

    if ((access_status = ap_run_fixups(r)) != OK) {
        ap_log_rerror(APLOG_MARK, APLOG_TRACE3, 0, r, &quot;fixups hook gave %d: %s&quot;,
                      access_status, r-&gt;uri);
        return access_status;
    }

    return OK;
}


/* Useful caching structures to repeat _walk/merge sequences as required
 * when a subrequest or redirect reuses substantially the same config.
 *
 * Directive order in the httpd.conf file and its Includes significantly
 * impact this optimization.  Grouping common blocks at the front of the
 * config that are less likely to change between a request and
 * its subrequests, or between a request and its redirects reduced
 * the work of these functions significantly.
 */

typedef struct walk_walked_t {
    ap_conf_vector_t *matched; /* A dir_conf sections we matched */
    ap_conf_vector_t *merged;  /* The dir_conf merged result */
} walk_walked_t;

typedef struct walk_cache_t {
    const char         *cached;          /* The identifier we matched */
    ap_conf_vector_t  **dir_conf_tested; /* The sections we matched against */
    ap_conf_vector_t   *dir_conf_merged; /* Base per_dir_config */
    ap_conf_vector_t   *per_dir_result;  /* per_dir_config += walked result */
    apr_array_header_t *walked;          /* The list of walk_walked_t results */
    struct walk_cache_t *prev; /* Prev cache of same call in this (sub)req */
    int count; /* Number of prev invocations of same call in this (sub)req */
} walk_cache_t;

static walk_cache_t *prep_walk_cache(apr_size_t t, request_rec *r)
{
    void **note, **inherit_note;
    walk_cache_t *cache, *prev_cache, *copy_cache;
    int count;

    /* Find the most relevant, recent walk cache to work from and provide
     * a copy the caller is allowed to munge.  In the case of a sub-request
     * or internal redirect, this is the cache corresponding to the equivalent
     * invocation of the same function call in the &quot;parent&quot; request, if such
     * a cache exists.  Otherwise it is the walk cache of the previous
     * invocation of the same function call in the current request, if
     * that exists; if not, then create a new walk cache.
     */
    note = ap_get_request_note(r, t);
    AP_DEBUG_ASSERT(note != NULL);

    copy_cache = prev_cache = *note;
    count = prev_cache ? (prev_cache-&gt;count + 1) : 0;

    if ((r-&gt;prev
         &amp;&amp; (inherit_note = ap_get_request_note(r-&gt;prev, t))
         &amp;&amp; *inherit_note)
        || (r-&gt;main
            &amp;&amp; (inherit_note = ap_get_request_note(r-&gt;main, t))
            &amp;&amp; *inherit_note)) {
        walk_cache_t *inherit_cache = *inherit_note;

        while (inherit_cache-&gt;count &gt; count) {
            inherit_cache = inherit_cache-&gt;prev;
        }
        if (inherit_cache-&gt;count == count) {
            copy_cache = inherit_cache;
        }
    }

    if (copy_cache) {
        cache = apr_pmemdup(r-&gt;pool, copy_cache, sizeof(*cache));
        cache-&gt;walked = apr_array_copy(r-&gt;pool, cache-&gt;walked);
        cache-&gt;prev = prev_cache;
        cache-&gt;count = count;
    }
    else {
        cache = apr_pcalloc(r-&gt;pool, sizeof(*cache));
        cache-&gt;walked = apr_array_make(r-&gt;pool, 4, sizeof(walk_walked_t));
    }

    *note = cache;

    return cache;
}

/*****************************************************************
 *
 * Getting and checking directory configuration.  Also checks the
 * FollowSymlinks and FollowSymOwner stuff, since this is really the
 * only place that can happen (barring a new mid_dir_walk callout).
 *
 * We can&#039;t do it as an access_checker module function which gets
 * called with the final per_dir_config, since we could have a directory
 * with FollowSymLinks disabled, which contains a symlink to another
 * with a .htaccess file which turns FollowSymLinks back on --- and
 * access in such a case must be denied.  So, whatever it is that
 * checks FollowSymLinks needs to know the state of the options as
 * they change, all the way down.
 */


/*
 * resolve_symlink must _always_ be called on an APR_LNK file type!
 * It will resolve the actual target file type, modification date, etc,
 * and provide any processing required for symlink evaluation.
 * Path must already be cleaned, no trailing slash, no multi-slashes,
 * and don&#039;t call this on the root!
 *
 * Simply, the number of times we deref a symlink are minimal compared
 * to the number of times we had an extra lstat() since we &#039;weren&#039;t sure&#039;.
 *
 * To optimize, we stat() anything when given (opts &amp; OPT_SYM_LINKS), otherwise
 * we start off with an lstat().  Every lstat() must be dereferenced in case
 * it points at a &#039;nasty&#039; - we must always rerun check_safe_file (or similar.)
 */
static int resolve_symlink(char *d, apr_finfo_t *lfi, int opts, apr_pool_t *p)
{
    apr_finfo_t fi;
    const char *savename;

    if (!(opts &amp; (OPT_SYM_OWNER | OPT_SYM_LINKS))) {
        return HTTP_FORBIDDEN;
    }

    /* Save the name from the valid bits. */
    savename = (lfi-&gt;valid &amp; APR_FINFO_NAME) ? lfi-&gt;name : NULL;

    /* if OPT_SYM_OWNER is unset, we only need to check target accessible */
    if (!(opts &amp; OPT_SYM_OWNER)) {
        if (apr_stat(&amp;fi, d, lfi-&gt;valid &amp; ~(APR_FINFO_NAME | APR_FINFO_LINK), p)
            != APR_SUCCESS)
        {
            return HTTP_FORBIDDEN;
        }

        /* Give back the target */
        memcpy(lfi, &amp;fi, sizeof(fi));
        if (savename) {
            lfi-&gt;name = savename;
            lfi-&gt;valid |= APR_FINFO_NAME;
        }

        return OK;
    }

    /* OPT_SYM_OWNER only works if we can get the owner of
     * both the file and symlink.  First fill in a missing
     * owner of the symlink, then get the info of the target.
     */
    if (!(lfi-&gt;valid &amp; APR_FINFO_OWNER)) {
        if (apr_stat(lfi, d, lfi-&gt;valid | APR_FINFO_LINK | APR_FINFO_OWNER, p)
            != APR_SUCCESS)
        {
            return HTTP_FORBIDDEN;
        }
    }

    if (apr_stat(&amp;fi, d, lfi-&gt;valid &amp; ~(APR_FINFO_NAME), p) != APR_SUCCESS) {
        return HTTP_FORBIDDEN;
    }

    if (apr_uid_compare(fi.user, lfi-&gt;user) != APR_SUCCESS) {
        return HTTP_FORBIDDEN;
    }

    /* Give back the target */
    memcpy(lfi, &amp;fi, sizeof(fi));
    if (savename) {
        lfi-&gt;name = savename;
        lfi-&gt;valid |= APR_FINFO_NAME;
    }

    return OK;
}


/*
 * As we walk the directory configuration, the merged config won&#039;t
 * be &#039;rooted&#039; to a specific vhost until the very end of the merge.
 *
 * We need a very fast mini-merge to a real, vhost-rooted merge
 * of core.opts and core.override, the only options tested within
 * directory_walk itself.
 *
 * See core.c::merge_core_dir_configs() for explanation.
 */

typedef struct core_opts_t {
        allow_options_t opts;
        allow_options_t add;
        allow_options_t remove;
        overrides_t override;
        overrides_t override_opts;
        apr_table_t *override_list;
} core_opts_t;

static void core_opts_merge(const ap_conf_vector_t *sec, core_opts_t *opts)
{
    core_dir_config *this_dir = ap_get_core_module_config(sec);

    if (!this_dir) {
        return;
    }

    if (this_dir-&gt;opts &amp; OPT_UNSET) {
        opts-&gt;add = (opts-&gt;add &amp; ~this_dir-&gt;opts_remove)
                   | this_dir-&gt;opts_add;
        opts-&gt;remove = (opts-&gt;remove &amp; ~this_dir-&gt;opts_add)
                      | this_dir-&gt;opts_remove;
        opts-&gt;opts = (opts-&gt;opts &amp; ~opts-&gt;remove) | opts-&gt;add;
    }
    else {
        opts-&gt;opts = this_dir-&gt;opts;
        opts-&gt;add = this_dir-&gt;opts_add;
        opts-&gt;remove = this_dir-&gt;opts_remove;
    }

    if (!(this_dir-&gt;override &amp; OR_UNSET)) {
        opts-&gt;override = this_dir-&gt;override;
        opts-&gt;override_opts = this_dir-&gt;override_opts;
    }

    if (this_dir-&gt;override_list != NULL) {
        opts-&gt;override_list = this_dir-&gt;override_list;
    }
}


/*****************************************************************
 *
 * Getting and checking directory configuration.  Also checks the
 * FollowSymlinks and FollowSymOwner stuff, since this is really the
 * only place that can happen (barring a new mid_dir_walk callout).
 *
 * We can&#039;t do it as an access_checker module function which gets
 * called with the final per_dir_config, since we could have a directory
 * with FollowSymLinks disabled, which contains a symlink to another
 * with a .htaccess file which turns FollowSymLinks back on --- and
 * access in such a case must be denied.  So, whatever it is that
 * checks FollowSymLinks needs to know the state of the options as
 * they change, all the way down.
 */

AP_DECLARE(int) ap_directory_walk(request_rec *r)
{
    ap_conf_vector_t *now_merged = NULL;
    core_server_config *sconf =
        ap_get_core_module_config(r-&gt;server-&gt;module_config);
    ap_conf_vector_t **sec_ent = (ap_conf_vector_t **) sconf-&gt;sec_dir-&gt;elts;
    int num_sec = sconf-&gt;sec_dir-&gt;nelts;
    walk_cache_t *cache;
    char *entry_dir;
    apr_status_t rv;
    int cached;

    /* XXX: Better (faster) tests needed!!!
     *
     * &quot;OK&quot; as a response to a real problem is not _OK_, but to allow broken
     * modules to proceed, we will permit the not-a-path filename to pass the
     * following two tests.  This behavior may be revoked in future versions
     * of Apache.  We still must catch it later if it&#039;s heading for the core
     * handler.  Leave INFO notes here for module debugging.
     */
    if (r-&gt;filename == NULL) {
        ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r, APLOGNO(00029)
                      &quot;Module bug?  Request filename is missing for URI %s&quot;,
                      r-&gt;uri);
        return OK;
    }

    /* Canonicalize the file path without resolving filename case or aliases
     * so we can begin by checking the cache for a recent directory walk.
     * This call will ensure we have an absolute path in the same pass.
     */
    if ((rv = apr_filepath_merge(&amp;entry_dir, NULL, r-&gt;filename,
                                 APR_FILEPATH_NOTRELATIVE, r-&gt;pool))
                  != APR_SUCCESS) {
        ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r, APLOGNO(00030)
                      &quot;Module bug?  Request filename path %s is invalid or &quot;
                      &quot;or not absolute for uri %s&quot;,
                      r-&gt;filename, r-&gt;uri);
        return OK;
    }

    /* XXX Notice that this forces path_info to be canonical.  That might
     * not be desired by all apps.  However, some of those same apps likely
     * have significant security holes.
     */
    r-&gt;filename = entry_dir;

    cache = prep_walk_cache(AP_NOTE_DIRECTORY_WALK, r);
    cached = (cache-&gt;cached != NULL);

    /* If this is not a dirent subrequest with a preconstructed
     * r-&gt;finfo value, then we can simply stat the filename to
     * save burning mega-cycles with unneeded stats - if this is
     * an exact file match.  We don&#039;t care about failure... we
     * will stat by component failing this meager attempt.
     *
     * It would be nice to distinguish APR_ENOENT from other
     * types of failure, such as APR_ENOTDIR.  We can do something
     * with APR_ENOENT, knowing that the path is good.
     */
    if (r-&gt;finfo.filetype == APR_NOFILE || r-&gt;finfo.filetype == APR_LNK) {
        rv = ap_run_dirwalk_stat(&amp;r-&gt;finfo, r, APR_FINFO_MIN);

        /* some OSs will return APR_SUCCESS/APR_REG if we stat
         * a regular file but we have &#039;/&#039; at the end of the name;
         *
         * other OSs will return APR_ENOTDIR for that situation;
         *
         * handle it the same everywhere by simulating a failure
         * if it looks like a directory but really isn&#039;t
         *
         * Also reset if the stat failed, just for safety.
         */
        if ((rv != APR_SUCCESS) ||
            (r-&gt;finfo.filetype != APR_NOFILE &amp;&amp;
             (r-&gt;finfo.filetype != APR_DIR) &amp;&amp;
             (r-&gt;filename[strlen(r-&gt;filename) - 1] == &#039;/&#039;))) {
             r-&gt;finfo.filetype = APR_NOFILE; /* forget what we learned */
        }
    }

    if (r-&gt;finfo.filetype == APR_REG) {
        entry_dir = ap_make_dirstr_parent(r-&gt;pool, entry_dir);
    }
    else if (r-&gt;filename[strlen(r-&gt;filename) - 1] != &#039;/&#039;) {
        entry_dir = apr_pstrcat(r-&gt;pool, r-&gt;filename, &quot;/&quot;, NULL);
    }

    /* If we have a file already matches the path of r-&gt;filename,
     * and the vhost&#039;s list of directory sections hasn&#039;t changed,
     * we can skip rewalking the directory_walk entries.
     */
    if (cached
        &amp;&amp; ((r-&gt;finfo.filetype == APR_REG)
            || ((r-&gt;finfo.filetype == APR_DIR)
                &amp;&amp; (!r-&gt;path_info || !*r-&gt;path_info)))
        &amp;&amp; (cache-&gt;dir_conf_tested == sec_ent)
        &amp;&amp; (strcmp(entry_dir, cache-&gt;cached) == 0)) {
        int familiar = 0;

        /* Well this looks really familiar!  If our end-result (per_dir_result)
         * didn&#039;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-&gt;per_dir_config.
         */
        if (r-&gt;per_dir_config == cache-&gt;per_dir_result) {
            familiar = 1;
        }

        if (r-&gt;per_dir_config == cache-&gt;dir_conf_merged) {
            r-&gt;per_dir_config = cache-&gt;per_dir_result;
            familiar = 1;
        }

        if (familiar) {
            apr_finfo_t thisinfo;
            int res;
            allow_options_t opts;
            core_dir_config *this_dir;

            this_dir = ap_get_core_module_config(r-&gt;per_dir_config);
            opts = this_dir-&gt;opts;
            /*
             * If Symlinks are allowed in general we do not need the following
             * check.
             */
            if (!(opts &amp; OPT_SYM_LINKS)) {
                rv = ap_run_dirwalk_stat(&amp;thisinfo, r,
                                         APR_FINFO_MIN | APR_FINFO_NAME | APR_FINFO_LINK);
                /*
                 * APR_INCOMPLETE is as fine as result as APR_SUCCESS as we
                 * have added APR_FINFO_NAME to the wanted parameter of
                 * apr_stat above. On Unix platforms this means that apr_stat
                 * is always going to return APR_INCOMPLETE in the case that
                 * the call to the native stat / lstat did not fail.
                 */
                if ((rv != APR_INCOMPLETE) &amp;&amp; (rv != APR_SUCCESS)) {
                    /*
                     * This should never happen, because we did a stat on the
                     * same file, resolving a possible symlink several lines
                     * above. Therefore do not make a detailed analysis of rv
                     * in this case for the reason of the failure, just bail out
                     * with a HTTP_FORBIDDEN in case we hit a race condition
                     * here.
                     */
                    ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(00031)
                                  &quot;access to %s failed; stat of &#039;%s&#039; failed.&quot;,
                                  r-&gt;uri, r-&gt;filename);
                    return r-&gt;status = HTTP_FORBIDDEN;
                }
                if (thisinfo.filetype == APR_LNK) {
                    /* Is this a possibly acceptable symlink? */
                    if ((res = resolve_symlink(r-&gt;filename, &amp;thisinfo,
                                               opts, r-&gt;pool)) != OK) {
                        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00032)
                                      &quot;Symbolic link not allowed &quot;
                                      &quot;or link target not accessible: %s&quot;,
                                      r-&gt;filename);
                        return r-&gt;status = res;
                    }
                }
            }
            return OK;
        }

        if (cache-&gt;walked-&gt;nelts) {
            now_merged = ((walk_walked_t*)cache-&gt;walked-&gt;elts)
                [cache-&gt;walked-&gt;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 sec_idx;
        int matches = cache-&gt;walked-&gt;nelts;
        int cached_matches = matches;
        walk_walked_t *last_walk = (walk_walked_t*)cache-&gt;walked-&gt;elts;
        core_dir_config *this_dir;
        core_opts_t opts;
        apr_finfo_t thisinfo;
        char *save_path_info;
        apr_size_t buflen;
        char *buf;
        unsigned int seg, startseg;
        apr_pool_t *rxpool = NULL;

        /* Invariant: from the first time filename_len is set until
         * it goes out of scope, filename_len==strlen(r-&gt;filename)
         */
        apr_size_t filename_len;
#ifdef CASE_BLIND_FILESYSTEM
        apr_size_t canonical_len;
#endif

        cached &amp;= auth_internal_per_conf;

        /*
         * We must play our own mini-merge game here, for the few
         * running dir_config values we care about within dir_walk.
         * We didn&#039;t start the merge from r-&gt;per_dir_config, so we
         * accumulate opts and override as we merge, from the globals.
         */
        this_dir = ap_get_core_module_config(r-&gt;per_dir_config);
        opts.opts = this_dir-&gt;opts;
        opts.add = this_dir-&gt;opts_add;
        opts.remove = this_dir-&gt;opts_remove;
        opts.override = this_dir-&gt;override;
        opts.override_opts = this_dir-&gt;override_opts;
        opts.override_list = this_dir-&gt;override_list;

        /* Set aside path_info to merge back onto path_info later.
         * If r-&gt;filename is a directory, we must remerge the path_info,
         * before we continue!  [Directories cannot, by definition, have
         * path info.  Either the next segment is not-found, or a file.]
         *
         * r-&gt;path_info tracks the unconsumed source path.
         * r-&gt;filename  tracks the path as we process it
         */
        if ((r-&gt;finfo.filetype == APR_DIR) &amp;&amp; r-&gt;path_info &amp;&amp; *r-&gt;path_info)
        {
            if ((rv = apr_filepath_merge(&amp;r-&gt;path_info, r-&gt;filename,
                                         r-&gt;path_info,
                                         APR_FILEPATH_NOTABOVEROOT, r-&gt;pool))
                != APR_SUCCESS) {
                ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(00033)
                              &quot;dir_walk error, path_info %s is not relative &quot;
                              &quot;to the filename path %s for uri %s&quot;,
                              r-&gt;path_info, r-&gt;filename, r-&gt;uri);
                return HTTP_INTERNAL_SERVER_ERROR;
            }

            save_path_info = NULL;
        }
        else {
            save_path_info = r-&gt;path_info;
            r-&gt;path_info = r-&gt;filename;
        }

#ifdef CASE_BLIND_FILESYSTEM

        canonical_len = 0;
        while (r-&gt;canonical_filename &amp;&amp; r-&gt;canonical_filename[canonical_len]
               &amp;&amp; (r-&gt;canonical_filename[canonical_len]
                   == r-&gt;path_info[canonical_len])) {
             ++canonical_len;
        }

        while (canonical_len
               &amp;&amp; ((r-&gt;canonical_filename[canonical_len - 1] != &#039;/&#039;
                   &amp;&amp; r-&gt;canonical_filename[canonical_len - 1])
                   || (r-&gt;path_info[canonical_len - 1] != &#039;/&#039;
                       &amp;&amp; r-&gt;path_info[canonical_len - 1]))) {
            --canonical_len;
        }

        /*
         * Now build r-&gt;filename component by component, starting
         * with the root (on Unix, simply &quot;/&quot;).  We will make a huge
         * assumption here for efficiency, that any canonical path
         * already given included a canonical root.
         */
        rv = apr_filepath_root((const char **)&amp;r-&gt;filename,
                               (const char **)&amp;r-&gt;path_info,
                               canonical_len ? 0 : APR_FILEPATH_TRUENAME,
                               r-&gt;pool);
        filename_len = strlen(r-&gt;filename);

        /*
         * Bad assumption above?  If the root&#039;s length is longer
         * than the canonical length, then it cannot be trusted as
         * a truename.  So try again, this time more seriously.
         */
        if ((rv == APR_SUCCESS) &amp;&amp; canonical_len
            &amp;&amp; (filename_len &gt; canonical_len)) {
            rv = apr_filepath_root((const char **)&amp;r-&gt;filename,
                                   (const char **)&amp;r-&gt;path_info,
                                   APR_FILEPATH_TRUENAME, r-&gt;pool);
            filename_len = strlen(r-&gt;filename);
            canonical_len = 0;
        }

#else /* ndef CASE_BLIND_FILESYSTEM, really this simple for Unix today; */

        rv = apr_filepath_root((const char **)&amp;r-&gt;filename,
                               (const char **)&amp;r-&gt;path_info,
                               0, r-&gt;pool);
        filename_len = strlen(r-&gt;filename);

#endif

        if (rv != APR_SUCCESS) {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(00034)
                          &quot;dir_walk error, could not determine the root &quot;
                          &quot;path of filename %s%s for uri %s&quot;,
                          r-&gt;filename, r-&gt;path_info, r-&gt;uri);
            return HTTP_INTERNAL_SERVER_ERROR;
        }

        /* Working space for terminating null and an extra / is required.
         */
        buflen = filename_len + strlen(r-&gt;path_info) + 2;
        buf = apr_palloc(r-&gt;pool, buflen);
        memcpy(buf, r-&gt;filename, filename_len + 1);
        r-&gt;filename = buf;
        thisinfo.valid = APR_FINFO_TYPE;
        thisinfo.filetype = APR_DIR; /* It&#039;s the root, of course it&#039;s a dir */

        /*
         * seg keeps track of which segment we&#039;ve copied.
         * sec_idx keeps track of which section we&#039;re on, since sections are
         *     ordered by number of segments. See core_reorder_directories
         * startseg tells us how many segments describe the root path
         *     e.g. the complete path &quot;//host/foo/&quot; to a UNC share (4)
         */
        startseg = seg = ap_count_dirs(r-&gt;filename);
        sec_idx = 0;

        /*
         * Go down the directory hierarchy.  Where we have to check for
         * symlinks, do so.  Where a .htaccess file has permission to
         * override anything, try to find one.
         */
        do {
            int res;
            char *seg_name;
            char *delim;
            int temp_slash=0;

            /* We have no trailing slash, but we sure would appreciate one.
             * However, we don&#039;t want to append a / our first time through.
             */
            if ((seg &gt; startseg) &amp;&amp; r-&gt;filename[filename_len-1] != &#039;/&#039;) {
                r-&gt;filename[filename_len++] = &#039;/&#039;;
                r-&gt;filename[filename_len] = 0;
                temp_slash=1;
            }

            /* Begin *this* level by looking for matching &lt;Directory&gt; sections
             * from the server config.
             */
            for (; sec_idx &lt; num_sec; ++sec_idx) {

                ap_conf_vector_t *entry_config = sec_ent[sec_idx];
                core_dir_config *entry_core;
                entry_core = ap_get_core_module_config(entry_config);

                /* No more possible matches for this many segments?
                 * We are done when we find relative/regex/longer components.
                 */
                if (entry_core-&gt;r || entry_core-&gt;d_components &gt; seg) {
                    break;
                }

                /* We will never skip &#039;0&#039; element components, e.g. plain old
                 * &lt;Directory &gt;, and &lt;Directory &quot;/&quot;&gt; are classified as zero
                 * so that Win32/Netware/OS2 etc all pick them up.
                 * Otherwise, skip over the mismatches.
                 */
                if (entry_core-&gt;d_components
                    &amp;&amp; ((entry_core-&gt;d_components &lt; seg)
                     || (entry_core-&gt;d_is_fnmatch
                         ? (apr_fnmatch(entry_core-&gt;d, r-&gt;filename,
                                        APR_FNM_PATHNAME) != APR_SUCCESS)
                         : (strcmp(r-&gt;filename, entry_core-&gt;d) != 0)))) {
                    continue;
                }

                /* If we haven&#039;t continue&#039;d above, we have a match.
                 *
                 * Calculate our full-context core opts &amp; override.
                 */
                core_opts_merge(sec_ent[sec_idx], &amp;opts);

                /* If we merged this same section last time, reuse it
                 */
                if (matches) {
                    if (last_walk-&gt;matched == sec_ent[sec_idx]) {
                        now_merged = last_walk-&gt;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-&gt;walked-&gt;nelts -= matches;
                    matches = 0;
                    cached = 0;
                }

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

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

            /* If .htaccess files are enabled, check for one, provided we
             * have reached a real path.
             */
            do {  /* Not really a loop, just a break&#039;able code block */

                ap_conf_vector_t *htaccess_conf = NULL;

                /* No htaccess in an incomplete root path,
                 * nor if it&#039;s disabled
                 */
                if (seg &lt; startseg || (!opts.override 
                    &amp;&amp; apr_is_empty_table(opts.override_list)
                    )) {
                    break;
                }


                res = ap_parse_htaccess(&amp;htaccess_conf, r, opts.override,
                                        opts.override_opts, opts.override_list,
                                        r-&gt;filename, sconf-&gt;access_name);
                if (res) {
                    return res;
                }

                if (!htaccess_conf) {
                    break;
                }

                /* If we are still here, we found our htaccess.
                 *
                 * Calculate our full-context core opts &amp; override.
                 */
                core_opts_merge(htaccess_conf, &amp;opts);

                /* If we merged this same htaccess last time, reuse it...
                 * this wouldn&#039;t work except that we cache the htaccess
                 * sections for the lifetime of the request, so we match
                 * the same conf.  Good planning (no, pure luck ;)
                 */
                if (matches) {
                    if (last_walk-&gt;matched == htaccess_conf) {
                        now_merged = last_walk-&gt;merged;
                        ++last_walk;
                        --matches;
                        break;
                    }

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

                if (now_merged) {
                    now_merged = ap_merge_per_dir_configs(r-&gt;pool,
                                                          now_merged,
                                                          htaccess_conf);
                }
                else {
                    now_merged = htaccess_conf;
                }

                last_walk = (walk_walked_t*)apr_array_push(cache-&gt;walked);
                last_walk-&gt;matched = htaccess_conf;
                last_walk-&gt;merged = now_merged;

            } while (0); /* Only one htaccess, not a real loop */

            /* That temporary trailing slash was useful, now drop it.
             */
            if (temp_slash) {
                r-&gt;filename[--filename_len] = &#039;\0&#039;;
            }

            /* Time for all good things to come to an end?
             */
            if (!r-&gt;path_info || !*r-&gt;path_info) {
                break;
            }

            /* Now it&#039;s time for the next segment...
             * We will assume the next element is an end node, and fix it up
             * below as necessary...
             */

            seg_name = r-&gt;filename + filename_len;
            delim = strchr(r-&gt;path_info + (*r-&gt;path_info == &#039;/&#039; ? 1 : 0), &#039;/&#039;);
            if (delim) {
                apr_size_t path_info_len = delim - r-&gt;path_info;
                *delim = &#039;\0&#039;;
                memcpy(seg_name, r-&gt;path_info, path_info_len + 1);
                filename_len += path_info_len;
                r-&gt;path_info = delim;
                *delim = &#039;/&#039;;
            }
            else {
                apr_size_t path_info_len = strlen(r-&gt;path_info);
                memcpy(seg_name, r-&gt;path_info, path_info_len + 1);
                filename_len += path_info_len;
                r-&gt;path_info += path_info_len;
            }
            if (*seg_name == &#039;/&#039;)
                ++seg_name;

            /* If nothing remained but a &#039;/&#039; string, we are finished
             * XXX: NO WE ARE NOT!!!  Now process this puppy!!! */
            if (!*seg_name) {
                break;
            }

            /* First optimization;
             * If...we knew r-&gt;filename was a file, and
             * if...we have strict (case-sensitive) filenames, or
             *      we know the canonical_filename matches to _this_ name, and
             * if...we have allowed symlinks
             * skip the lstat and dummy up an APR_DIR value for thisinfo.
             */
            if (r-&gt;finfo.filetype != APR_NOFILE
#ifdef CASE_BLIND_FILESYSTEM
                &amp;&amp; (filename_len &lt;= canonical_len)
#endif
                &amp;&amp; ((opts.opts &amp; (OPT_SYM_OWNER | OPT_SYM_LINKS)) == OPT_SYM_LINKS))
            {

                thisinfo.filetype = APR_DIR;
                ++seg;
                continue;
            }

            /* We choose apr_stat with flag APR_FINFO_LINK here, rather that
             * plain apr_stat, so that we capture this path object rather than
             * its target.  We will replace the info with our target&#039;s info
             * below.  We especially want the name of this &#039;link&#039; object, not
             * the name of its target, if we are fixing the filename
             * case/resolving aliases.
             */
            rv = ap_run_dirwalk_stat(&amp;thisinfo, r,
                                     APR_FINFO_MIN | APR_FINFO_NAME | APR_FINFO_LINK);

            if (APR_STATUS_IS_ENOENT(rv)) {
                /* Nothing?  That could be nice.  But our directory
                 * walk is done.
                 */
                thisinfo.filetype = APR_NOFILE;
                break;
            }
            else if (APR_STATUS_IS_EACCES(rv)) {
                ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(00035)
                              &quot;access to %s denied (filesystem path &#039;%s&#039;) &quot;
                              &quot;because search permissions are missing on a &quot;
                              &quot;component of the path&quot;, r-&gt;uri, r-&gt;filename);
                return r-&gt;status = HTTP_FORBIDDEN;
            }
            else if ((rv != APR_SUCCESS &amp;&amp; rv != APR_INCOMPLETE)
                     || !(thisinfo.valid &amp; APR_FINFO_TYPE)) {
                /* If we hit ENOTDIR, we must have over-optimized, deny
                 * rather than assume not found.
                 */
                ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(00036)
                              &quot;access to %s failed (filesystem path &#039;%s&#039;)&quot;, 
                              r-&gt;uri, r-&gt;filename);
                return r-&gt;status = HTTP_FORBIDDEN;
            }

            /* Fix up the path now if we have a name, and they don&#039;t agree
             */
            if ((thisinfo.valid &amp; APR_FINFO_NAME)
                &amp;&amp; strcmp(seg_name, thisinfo.name)) {
                /* TODO: provide users an option that an internal/external
                 * redirect is required here?  We need to walk the URI and
                 * filename in tandem to properly correlate these.
                 */
                strcpy(seg_name, thisinfo.name);
                filename_len = strlen(r-&gt;filename);
            }

            if (thisinfo.filetype == APR_LNK) {
                /* Is this a possibly acceptable symlink?
                 */
                if ((res = resolve_symlink(r-&gt;filename, &amp;thisinfo,
                                           opts.opts, r-&gt;pool)) != OK) {
                    ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00037)
                                  &quot;Symbolic link not allowed &quot;
                                  &quot;or link target not accessible: %s&quot;,
                                  r-&gt;filename);
                    return r-&gt;status = res;
                }
            }

            /* Ok, we are done with the link&#039;s info, test the real target
             */
            if (thisinfo.filetype == APR_REG ||
                thisinfo.filetype == APR_NOFILE) {
                /* That was fun, nothing left for us here
                 */
                break;
            }
            else if (thisinfo.filetype != APR_DIR) {
                ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00038)
                              &quot;Forbidden: %s doesn&#039;t point to &quot;
                              &quot;a file or directory&quot;,
                              r-&gt;filename);
                return r-&gt;status = HTTP_FORBIDDEN;
            }

            ++seg;
        } while (thisinfo.filetype == APR_DIR);

        /* If we have _not_ optimized, this is the time to recover
         * the final stat result.
         */
        if (r-&gt;finfo.filetype == APR_NOFILE || r-&gt;finfo.filetype == APR_LNK) {
            r-&gt;finfo = thisinfo;
        }

        /* Now splice the saved path_info back onto any new path_info
         */
        if (save_path_info) {
            if (r-&gt;path_info &amp;&amp; *r-&gt;path_info) {
                r-&gt;path_info = ap_make_full_path(r-&gt;pool, r-&gt;path_info,
                                                 save_path_info);
            }
            else {
                r-&gt;path_info = save_path_info;
            }
        }

        /*
         * Now we&#039;ll deal with the regexes, note we pick up sec_idx
         * where we left off (we gave up after we hit entry_core-&gt;r)
         */
        for (; sec_idx &lt; num_sec; ++sec_idx) {

            int nmatch = 0;
            int i;
            ap_regmatch_t *pmatch = NULL;

            core_dir_config *entry_core;
            entry_core = ap_get_core_module_config(sec_ent[sec_idx]);

            if (!entry_core-&gt;r) {
                continue;
            }

            if (entry_core-&gt;refs &amp;&amp; entry_core-&gt;refs-&gt;nelts) {
                if (!rxpool) {
                    apr_pool_create(&amp;rxpool, r-&gt;pool);
                    apr_pool_tag(rxpool, &quot;directory_walk_rxpool&quot;);
                }
                nmatch = entry_core-&gt;refs-&gt;nelts;
                pmatch = apr_palloc(rxpool, nmatch*sizeof(ap_regmatch_t));
            }

            if (ap_regexec(entry_core-&gt;r, r-&gt;filename, nmatch, pmatch, 0)) {
                continue;
            }

            for (i = 0; i &lt; nmatch; i++) {
                if (pmatch[i].rm_so &gt;= 0 &amp;&amp; pmatch[i].rm_eo &gt;= 0 &amp;&amp;
                    ((const char **)entry_core-&gt;refs-&gt;elts)[i]) {
                    apr_table_setn(r-&gt;subprocess_env, 
                                   ((const char **)entry_core-&gt;refs-&gt;elts)[i],
                                   apr_pstrndup(r-&gt;pool,
                                   r-&gt;filename + pmatch[i].rm_so,
                                   pmatch[i].rm_eo - pmatch[i].rm_so));
                }
            }

            /* If we haven&#039;t already continue&#039;d above, we have a match.
             *
             * Calculate our full-context core opts &amp; override.
             */
            core_opts_merge(sec_ent[sec_idx], &amp;opts);

            /* If we merged this same section last time, reuse it
             */
            if (matches) {
                if (last_walk-&gt;matched == sec_ent[sec_idx]) {
                    now_merged = last_walk-&gt;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-&gt;walked-&gt;nelts -= matches;
                matches = 0;
                cached = 0;
            }

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

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

        if (rxpool) {
            apr_pool_destroy(rxpool);
        }

        /* Whoops - everything matched in sequence, but either the original
         * walk found some additional matches (which we need to truncate), or
         * this walk found some additional matches.
         */
        if (matches) {
            cache-&gt;walked-&gt;nelts -= matches;
            cached = 0;
        }
        else if (cache-&gt;walked-&gt;nelts &gt; cached_matches) {
            cached = 0;
        }
    }

/* It seems this shouldn&#039;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-&gt;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-&gt;finfo.filetype != APR_DIR
 x       &amp;&amp; (res = resolve_symlink(r-&gt;filename, r-&gt;info, ap_allow_options(r),
 x                                 r-&gt;pool))) {
 x       ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
 x                     &quot;Symbolic link not allowed: %s&quot;, r-&gt;filename);
 x       return res;
 x   }
 */

    /* Save future sub-requestors much angst in processing
     * this subrequest.  If dir_walk couldn&#039;t canonicalize
     * the file path, nothing can.
     */
    r-&gt;canonical_filename = r-&gt;filename;

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

    if (cached
        &amp;&amp; r-&gt;per_dir_config == cache-&gt;dir_conf_merged) {
        r-&gt;per_dir_config = cache-&gt;per_dir_result;
        return OK;
    }

    cache-&gt;dir_conf_tested = sec_ent;
    cache-&gt;dir_conf_merged = r-&gt;per_dir_config;

    /* Merge our cache-&gt;dir_conf_merged construct with the r-&gt;per_dir_configs,
     * and note the end result to (potentially) skip this step next time.
     */
    if (now_merged) {
        r-&gt;per_dir_config = ap_merge_per_dir_configs(r-&gt;pool,
                                                     r-&gt;per_dir_config,
                                                     now_merged);
    }
    cache-&gt;per_dir_result = r-&gt;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_core_module_config(r-&gt;server-&gt;module_config);
    ap_conf_vector_t **sec_ent = (ap_conf_vector_t **)sconf-&gt;sec_url-&gt;elts;
    int num_sec = sconf-&gt;sec_url-&gt;nelts;
    walk_cache_t *cache;
    const char *entry_uri;
    int cached;

    /* No tricks here, there are no &lt;Locations &gt; to parse in this vhost.
     * We won&#039;t destroy the cache, just in case _this_ redirect is later
     * redirected again to a vhost with &lt;Location &gt; blocks to optimize.
     */
    if (!num_sec) {
        return OK;
    }

    cache = prep_walk_cache(AP_NOTE_LOCATION_WALK, r);
    cached = (cache-&gt;cached != NULL);

   /*
    * When merge_slashes is set to AP_CORE_CONFIG_OFF the slashes in r-&gt;uri
    * have not been merged. But for Location walks we always go with merged
    * slashes no matter what merge_slashes is set to.
    */
    if (sconf-&gt;merge_slashes != AP_CORE_CONFIG_OFF) {
        entry_uri = r-&gt;uri;
    }
    else {
        char *uri = apr_pstrdup(r-&gt;pool, r-&gt;uri);
        ap_no2slash(uri);
        entry_uri = uri;
    }

    /* If we have an cache-&gt;cached location that matches r-&gt;uri,
     * and the vhost&#039;s list of locations hasn&#039;t changed, we can skip
     * rewalking the location_walk entries.
     */
    if (cached
        &amp;&amp; (cache-&gt;dir_conf_tested == sec_ent)
        &amp;&amp; (strcmp(entry_uri, cache-&gt;cached) == 0)) {
        /* Well this looks really familiar!  If our end-result (per_dir_result)
         * didn&#039;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-&gt;per_dir_config.
         */
        if (r-&gt;per_dir_config == cache-&gt;per_dir_result) {
            return OK;
        }

        if (cache-&gt;walked-&gt;nelts) {
            now_merged = ((walk_walked_t*)cache-&gt;walked-&gt;elts)
                                            [cache-&gt;walked-&gt;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-&gt;walked-&gt;nelts;
        int cached_matches = matches;
        walk_walked_t *last_walk = (walk_walked_t*)cache-&gt;walked-&gt;elts;
        apr_pool_t *rxpool = NULL;

        cached &amp;= auth_internal_per_conf;
        cache-&gt;cached = apr_pstrdup(r-&gt;pool, 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 &lt; num_sec; ++sec_idx) {

            core_dir_config *entry_core;
            entry_core = ap_get_core_module_config(sec_ent[sec_idx]);

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

            /* Test the regex, fnmatch or string as appropriate.
             * If it&#039;s a strcmp, and the &lt;Location &gt; pattern was
             * not slash terminated, then this uri must be slash
             * terminated (or at the end of the string) to match.
             */
            if (entry_core-&gt;r) {

                int nmatch = 0;
                int i;
                ap_regmatch_t *pmatch = NULL;

                if (entry_core-&gt;refs &amp;&amp; entry_core-&gt;refs-&gt;nelts) {
                    if (!rxpool) {
                        apr_pool_create(&amp;rxpool, r-&gt;pool);
                        apr_pool_tag(rxpool, &quot;location_walk_rxpool&quot;);
                    }
                    nmatch = entry_core-&gt;refs-&gt;nelts;
                    pmatch = apr_palloc(rxpool, nmatch*sizeof(ap_regmatch_t));
                }

                if (ap_regexec(entry_core-&gt;r, r-&gt;uri, nmatch, pmatch, 0)) {
                    continue;
                }

                for (i = 0; i &lt; nmatch; i++) {
                    if (pmatch[i].rm_so &gt;= 0 &amp;&amp; pmatch[i].rm_eo &gt;= 0 &amp;&amp; 
                        ((const char **)entry_core-&gt;refs-&gt;elts)[i]) {
                        apr_table_setn(r-&gt;subprocess_env,
                                       ((const char **)entry_core-&gt;refs-&gt;elts)[i],
                                       apr_pstrndup(r-&gt;pool,
                                       r-&gt;uri + pmatch[i].rm_so,
                                       pmatch[i].rm_eo - pmatch[i].rm_so));
                    }
                }

            }
            else {

                if ((entry_core-&gt;d_is_fnmatch
                   ? apr_fnmatch(entry_core-&gt;d, cache-&gt;cached, APR_FNM_PATHNAME)
                   : (strncmp(entry_core-&gt;d, cache-&gt;cached, len)
                      || (len &gt; 0
                          &amp;&amp; entry_core-&gt;d[len - 1] != &#039;/&#039;
                          &amp;&amp; cache-&gt;cached[len] != &#039;/&#039;
                          &amp;&amp; cache-&gt;cached[len] != &#039;\0&#039;)))) {
                    continue;
                }

            }

            /* If we merged this same section last time, reuse it
             */
            if (matches) {
                if (last_walk-&gt;matched == sec_ent[sec_idx]) {
                    now_merged = last_walk-&gt;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-&gt;walked-&gt;nelts -= matches;
                matches = 0;
                cached = 0;
            }

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

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

        if (rxpool) {
            apr_pool_destroy(rxpool);
        }

        /* Whoops - everything matched in sequence, but either the original
         * walk found some additional matches (which we need to truncate), or
         * this walk found some additional matches.
         */
        if (matches) {
            cache-&gt;walked-&gt;nelts -= matches;
            cached = 0;
        }
        else if (cache-&gt;walked-&gt;nelts &gt; cached_matches) {
            cached = 0;
        }
    }

    if (cached
        &amp;&amp; r-&gt;per_dir_config == cache-&gt;dir_conf_merged) {
        r-&gt;per_dir_config = cache-&gt;per_dir_result;
        return OK;
    }

    cache-&gt;dir_conf_tested = sec_ent;
    cache-&gt;dir_conf_merged = r-&gt;per_dir_config;

    /* Merge our cache-&gt;dir_conf_merged construct with the r-&gt;per_dir_configs,
     * and note the end result to (potentially) skip this step next time.
     */
    if (now_merged) {
        r-&gt;per_dir_config = ap_merge_per_dir_configs(r-&gt;pool,
                                                     r-&gt;per_dir_config,
                                                     now_merged);
    }
    cache-&gt;per_dir_result = r-&gt;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_core_module_config(r-&gt;per_dir_config);
    ap_conf_vector_t **sec_ent = NULL;
    int num_sec = 0;
    walk_cache_t *cache;
    const char *test_file;
    int cached;

    if (dconf-&gt;sec_file) {
        sec_ent = (ap_conf_vector_t **)dconf-&gt;sec_file-&gt;elts;
        num_sec = dconf-&gt;sec_file-&gt;nelts;
    }

    /* To allow broken modules to proceed, we allow missing filenames to pass.
     * We will catch it later if it&#039;s heading for the core handler.
     * directory_walk already posted an INFO note for module debugging.
     */
    if (r-&gt;filename == NULL) {
        return OK;
    }

    /* No tricks here, there are just no &lt;Files &gt; to parse in this context.
     * We won&#039;t destroy the cache, just in case _this_ redirect is later
     * redirected again to a context containing the same or similar &lt;Files &gt;.
     */
    if (!num_sec) {
        return OK;
    }

    cache = prep_walk_cache(AP_NOTE_FILE_WALK, r);
    cached = (cache-&gt;cached != NULL);

    /* Get the basename .. and copy for the cache just
     * in case r-&gt;filename is munged by another module
     */
    test_file = strrchr(r-&gt;filename, &#039;/&#039;);
    if (test_file == NULL) {
        test_file = apr_pstrdup(r-&gt;pool, r-&gt;filename);
    }
    else {
        test_file = apr_pstrdup(r-&gt;pool, ++test_file);
    }

    /* If we have an cache-&gt;cached file name that matches test_file,
     * and the directory&#039;s list of file sections hasn&#039;t changed, we
     * can skip rewalking the file_walk entries.
     */
    if (cached
        &amp;&amp; (cache-&gt;dir_conf_tested == sec_ent)
        &amp;&amp; (strcmp(test_file, cache-&gt;cached) == 0)) {
        /* Well this looks really familiar!  If our end-result (per_dir_result)
         * didn&#039;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-&gt;per_dir_config.
         */
        if (r-&gt;per_dir_config == cache-&gt;per_dir_result) {
            return OK;
        }

        if (cache-&gt;walked-&gt;nelts) {
            now_merged = ((walk_walked_t*)cache-&gt;walked-&gt;elts)
                [cache-&gt;walked-&gt;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-&gt;walked-&gt;nelts;
        int cached_matches = matches;
        walk_walked_t *last_walk = (walk_walked_t*)cache-&gt;walked-&gt;elts;
        apr_pool_t *rxpool = NULL;

        cached &amp;= auth_internal_per_conf;
        cache-&gt;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 &lt; num_sec; ++sec_idx) {
            core_dir_config *entry_core;
            entry_core = ap_get_core_module_config(sec_ent[sec_idx]);

            if (entry_core-&gt;r) {

                int nmatch = 0;
                int i;
                ap_regmatch_t *pmatch = NULL;

                if (entry_core-&gt;refs &amp;&amp; entry_core-&gt;refs-&gt;nelts) {
                    if (!rxpool) {
                        apr_pool_create(&amp;rxpool, r-&gt;pool);
                        apr_pool_tag(rxpool, &quot;file_walk_rxpool&quot;);
                    }
                    nmatch = entry_core-&gt;refs-&gt;nelts;
                    pmatch = apr_palloc(rxpool, nmatch*sizeof(ap_regmatch_t));
                }

                if (ap_regexec(entry_core-&gt;r, cache-&gt;cached, nmatch, pmatch, 0)) {
                    continue;
                }

                for (i = 0; i &lt; nmatch; i++) {
                    if (pmatch[i].rm_so &gt;= 0 &amp;&amp; pmatch[i].rm_eo &gt;= 0 &amp;&amp; 
                        ((const char **)entry_core-&gt;refs-&gt;elts)[i]) {
                        apr_table_setn(r-&gt;subprocess_env,
                                       ((const char **)entry_core-&gt;refs-&gt;elts)[i],
                                       apr_pstrndup(r-&gt;pool,
                                       cache-&gt;cached + pmatch[i].rm_so,
                                       pmatch[i].rm_eo - pmatch[i].rm_so));
                    }
                }

            }
            else {
                if ((entry_core-&gt;d_is_fnmatch
                       ? apr_fnmatch(entry_core-&gt;d, cache-&gt;cached, APR_FNM_PATHNAME)
                       : strcmp(entry_core-&gt;d, cache-&gt;cached))) {
                    continue;
                }
            }

            /* If we merged this same section last time, reuse it
             */
            if (matches) {
                if (last_walk-&gt;matched == sec_ent[sec_idx]) {
                    now_merged = last_walk-&gt;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-&gt;walked-&gt;nelts -= matches;
                matches = 0;
                cached = 0;
            }

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

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

        if (rxpool) {
            apr_pool_destroy(rxpool);
        }

        /* Whoops - everything matched in sequence, but either the original
         * walk found some additional matches (which we need to truncate), or
         * this walk found some additional matches.
         */
        if (matches) {
            cache-&gt;walked-&gt;nelts -= matches;
            cached = 0;
        }
        else if (cache-&gt;walked-&gt;nelts &gt; cached_matches) {
            cached = 0;
        }
    }

    if (cached
        &amp;&amp; r-&gt;per_dir_config == cache-&gt;dir_conf_merged) {
        r-&gt;per_dir_config = cache-&gt;per_dir_result;
        return OK;
    }

    cache-&gt;dir_conf_tested = sec_ent;
    cache-&gt;dir_conf_merged = r-&gt;per_dir_config;

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

    return OK;
}

static int ap_if_walk_sub(request_rec *r, core_dir_config* dconf)
{
    ap_conf_vector_t *now_merged = NULL;
    ap_conf_vector_t **sec_ent = NULL;
    int num_sec = 0;
    walk_cache_t *cache;
    int cached;
    int sec_idx;
    int matches;
    int cached_matches;
    int prev_result = -1;
    walk_walked_t *last_walk;

    if (dconf &amp;&amp; dconf-&gt;sec_if) {
        sec_ent = (ap_conf_vector_t **)dconf-&gt;sec_if-&gt;elts;
        num_sec = dconf-&gt;sec_if-&gt;nelts;
    }

    /* No tricks here, there are just no &lt;If &gt; to parse in this context.
     * We won&#039;t destroy the cache, just in case _this_ redirect is later
     * redirected again to a context containing the same or similar &lt;If &gt;.
     */
    if (!num_sec) {
        return OK;
    }

    cache = prep_walk_cache(AP_NOTE_IF_WALK, r);
    cached = (cache-&gt;cached != NULL);
    cache-&gt;cached = (void *)1;
    matches = cache-&gt;walked-&gt;nelts;
    cached_matches = matches;
    last_walk = (walk_walked_t*)cache-&gt;walked-&gt;elts;

    cached &amp;= auth_internal_per_conf;

    /* Go through the if entries, and check for matches  */
    for (sec_idx = 0; sec_idx &lt; num_sec; ++sec_idx) {
        const char *err = NULL;
        core_dir_config *entry_core;
        int rc;
        entry_core = ap_get_core_module_config(sec_ent[sec_idx]);

        AP_DEBUG_ASSERT(entry_core-&gt;condition_ifelse != 0);
        if (entry_core-&gt;condition_ifelse &amp; AP_CONDITION_ELSE) {
            AP_DEBUG_ASSERT(prev_result != -1);
            if (prev_result == 1)
                continue;
        }

        if (entry_core-&gt;condition_ifelse &amp; AP_CONDITION_IF) {
            rc = ap_expr_exec(r, entry_core-&gt;condition, &amp;err);
            if (rc &lt;= 0) {
                if (rc &lt; 0)
                    ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00039)
                                  &quot;Failed to evaluate &lt;If &gt; condition: %s&quot;,
                                  err);
                prev_result = 0;
                continue;
            }
            prev_result = 1;
        }
        else {
            prev_result = -1;
        }

        /* If we merged this same section last time, reuse it
         */
        if (matches) {
            if (last_walk-&gt;matched == sec_ent[sec_idx]) {
                now_merged = last_walk-&gt;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-&gt;walked-&gt;nelts -= matches;
            matches = 0;
            cached = 0;
        }

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

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

    /* Everything matched in sequence, but it may be that the original
     * walk found some additional matches (which we need to truncate), or
     * this walk found some additional matches.
     */
    if (matches) {
        cache-&gt;walked-&gt;nelts -= matches;
        cached = 0;
    }
    else if (cache-&gt;walked-&gt;nelts &gt; cached_matches) {
        cached = 0;
    }

    if (cached
        &amp;&amp; r-&gt;per_dir_config == cache-&gt;dir_conf_merged) {
        r-&gt;per_dir_config = cache-&gt;per_dir_result;
        return OK;
    }

    cache-&gt;dir_conf_tested = sec_ent;
    cache-&gt;dir_conf_merged = r-&gt;per_dir_config;

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

    if (now_merged) {
        core_dir_config *dconf_merged = ap_get_core_module_config(now_merged);

        /* Allow nested &lt;If&gt;s and their configs to get merged
         * with the current one.
         */
        return ap_if_walk_sub(r, dconf_merged);
    }

    return OK;
}

AP_DECLARE(int) ap_if_walk(request_rec *r)
{
    core_dir_config *dconf = ap_get_core_module_config(r-&gt;per_dir_config);
    int status = ap_if_walk_sub(r, dconf);
    return status;
}

/*****************************************************************
 *
 * The sub_request mechanism.
 *
 * Fns to look up a relative URI from, e.g., a map file or SSI document.
 * These do all access checks, etc., but don&#039;t actually run the transaction
 * ... use run_sub_req below for that.  Also, be sure to use destroy_sub_req
 * as appropriate if you&#039;re likely to be creating more than a few of these.
 * (An early Apache version didn&#039;t destroy the sub_reqs used in directory
 * indexing.  The result, when indexing a directory with 800-odd files in
 * it, was massively excessive storage allocation).
 *
 * Note more manipulation of protocol-specific vars in the request
 * structure...
 */

static request_rec *make_sub_request(const request_rec *r,
                                     ap_filter_t *next_filter)
{
    apr_pool_t *rrp;
    request_rec *rnew;

    apr_pool_create(&amp;rrp, r-&gt;pool);
    apr_pool_tag(rrp, &quot;subrequest&quot;);
    rnew = apr_pcalloc(rrp, sizeof(request_rec));
    rnew-&gt;pool = rrp;

    rnew-&gt;hostname       = r-&gt;hostname;
    rnew-&gt;request_time   = r-&gt;request_time;
    rnew-&gt;connection     = r-&gt;connection;
    rnew-&gt;server         = r-&gt;server;
    rnew-&gt;log            = r-&gt;log;

    rnew-&gt;request_config = ap_create_request_config(rnew-&gt;pool);

    /* Start a clean config from this subrequest&#039;s vhost.  Optimization in
     * Location/File/Dir walks from the parent request assure that if the
     * config blocks of the subrequest match the parent request, no merges
     * will actually occur (and generally a minimal number of merges are
     * required, even if the parent and subrequest aren&#039;t quite identical.)
     */
    rnew-&gt;per_dir_config = r-&gt;server-&gt;lookup_defaults;

    rnew-&gt;htaccess = r-&gt;htaccess;
    rnew-&gt;allowed_methods = ap_make_method_list(rnew-&gt;pool, 2);

    /* make a copy of the allowed-methods list */
    ap_copy_method_list(rnew-&gt;allowed_methods, r-&gt;allowed_methods);

    /* start with the same set of output filters */
    if (next_filter) {
        ap_filter_t *scan = next_filter;

        /* while there are no input filters for a subrequest, we will
         * try to insert some, so if we don&#039;t have valid data, the code
         * will seg fault.
         */
        rnew-&gt;input_filters = r-&gt;input_filters;
        rnew-&gt;proto_input_filters = r-&gt;proto_input_filters;
        rnew-&gt;output_filters = next_filter;
        rnew-&gt;proto_output_filters = r-&gt;proto_output_filters;
        while (scan &amp;&amp; (scan != r-&gt;proto_output_filters)) {
            if (scan-&gt;frec == ap_subreq_core_filter_handle) {
                break;
            }
            scan = scan-&gt;next;
        }
        if (!scan || scan == r-&gt;proto_output_filters) {
            ap_add_output_filter_handle(ap_subreq_core_filter_handle,
                    NULL, rnew, rnew-&gt;connection);
        }
    }
    else {
        /* If NULL - we are expecting to be internal_fast_redirect&#039;ed
         * to this subrequest - or this request will never be invoked.
         * Ignore the original request filter stack entirely, and
         * drill the input and output stacks back to the connection.
         */
        rnew-&gt;proto_input_filters = r-&gt;proto_input_filters;
        rnew-&gt;proto_output_filters = r-&gt;proto_output_filters;

        rnew-&gt;input_filters = r-&gt;proto_input_filters;
        rnew-&gt;output_filters = r-&gt;proto_output_filters;
    }

    rnew-&gt;useragent_addr = r-&gt;useragent_addr;
    rnew-&gt;useragent_ip = r-&gt;useragent_ip;

    /* no input filters for a subrequest */

    ap_set_sub_req_protocol(rnew, r);

    /* We have to run this after we fill in sub req vars,
     * or the r-&gt;main pointer won&#039;t be setup
     */
    ap_run_create_request(rnew);

    /* Begin by presuming any module can make its own path_info assumptions,
     * until some module interjects and changes the value.
     */
    rnew-&gt;used_path_info = AP_REQ_DEFAULT_PATH_INFO;

    /* Pass on the kept body (if any) into the new request. */
    rnew-&gt;kept_body = r-&gt;kept_body;

    return rnew;
}

AP_CORE_DECLARE_NONSTD(apr_status_t) ap_sub_req_output_filter(ap_filter_t *f,
                                                              apr_bucket_brigade *bb)
{
    apr_bucket *e = APR_BRIGADE_LAST(bb);

    if (APR_BUCKET_IS_EOS(e)) {
        apr_bucket_delete(e);
    }

    if (!APR_BRIGADE_EMPTY(bb)) {
        return ap_pass_brigade(f-&gt;next, bb);
    }

    return APR_SUCCESS;
}

extern APR_OPTIONAL_FN_TYPE(authz_some_auth_required) *ap__authz_ap_some_auth_required;

AP_DECLARE(int) ap_some_auth_required(request_rec *r)
{
    /* Is there a require line configured for the type of *this* req? */
    if (ap__authz_ap_some_auth_required) {
        return ap__authz_ap_some_auth_required(r);
    }
    else
        return 0;
}

AP_DECLARE(void) ap_clear_auth_internal(void)
{
    auth_internal_per_conf_hooks = 0;
    auth_internal_per_conf_providers = 0;
}

AP_DECLARE(void) ap_setup_auth_internal(apr_pool_t *ptemp)
{
    int total_auth_hooks = 0;
    int total_auth_providers = 0;

    auth_internal_per_conf = 0;

    if (_hooks.link_access_checker) {
        total_auth_hooks += _hooks.link_access_checker-&gt;nelts;
    }
    if (_hooks.link_access_checker_ex) {
        total_auth_hooks += _hooks.link_access_checker_ex-&gt;nelts;
    }
    if (_hooks.link_check_user_id) {
        total_auth_hooks += _hooks.link_check_user_id-&gt;nelts;
    }
    if (_hooks.link_auth_checker) {
        total_auth_hooks += _hooks.link_auth_checker-&gt;nelts;
    }

    if (total_auth_hooks &gt; auth_internal_per_conf_hooks) {
        return;
    }

    total_auth_providers +=
        ap_list_provider_names(ptemp, AUTHN_PROVIDER_GROUP,
                               AUTHN_PROVIDER_VERSION)-&gt;nelts;
    total_auth_providers +=
        ap_list_provider_names(ptemp, AUTHZ_PROVIDER_GROUP,
                               AUTHZ_PROVIDER_VERSION)-&gt;nelts;

    if (total_auth_providers &gt; auth_internal_per_conf_providers) {
        return;
    }

    auth_internal_per_conf = 1;
}

AP_DECLARE(apr_status_t) ap_register_auth_provider(apr_pool_t *pool,
                                                   const char *provider_group,
                                                   const char *provider_name,
                                                   const char *provider_version,
                                                   const void *provider,
                                                   int type)
{
    if ((type &amp; AP_AUTH_INTERNAL_MASK) == AP_AUTH_INTERNAL_PER_CONF) {
        ++auth_internal_per_conf_providers;
    }

    return ap_register_provider(pool, provider_group, provider_name,
                                provider_version, provider);
}

AP_DECLARE(void) ap_hook_check_access(ap_HOOK_access_checker_t *pf,
                                      const char * const *aszPre,
                                      const char * const *aszSucc,
                                      int nOrder, int type)
{
    if ((type &amp; AP_AUTH_INTERNAL_MASK) == AP_AUTH_INTERNAL_PER_CONF) {
        ++auth_internal_per_conf_hooks;
    }

    ap_hook_access_checker(pf, aszPre, aszSucc, nOrder);
}

AP_DECLARE(void) ap_hook_check_access_ex(ap_HOOK_access_checker_ex_t *pf,
                                      const char * const *aszPre,
                                      const char * const *aszSucc,
                                      int nOrder, int type)
{
    if ((type &amp; AP_AUTH_INTERNAL_MASK) == AP_AUTH_INTERNAL_PER_CONF) {
        ++auth_internal_per_conf_hooks;
    }

    ap_hook_access_checker_ex(pf, aszPre, aszSucc, nOrder);
}

AP_DECLARE(void) ap_hook_check_authn(ap_HOOK_check_user_id_t *pf,
                                     const char * const *aszPre,
                                     const char * const *aszSucc,
                                     int nOrder, int type)
{
    if ((type &amp; AP_AUTH_INTERNAL_MASK) == AP_AUTH_INTERNAL_PER_CONF) {
        ++auth_internal_per_conf_hooks;
    }

    ap_hook_check_user_id(pf, aszPre, aszSucc, nOrder);
}

AP_DECLARE(void) ap_hook_check_authz(ap_HOOK_auth_checker_t *pf,
                                     const char * const *aszPre,
                                     const char * const *aszSucc,
                                     int nOrder, int type)
{
    if ((type &amp; AP_AUTH_INTERNAL_MASK) == AP_AUTH_INTERNAL_PER_CONF) {
        ++auth_internal_per_conf_hooks;
    }

    ap_hook_auth_checker(pf, aszPre, aszSucc, nOrder);
}

AP_DECLARE(request_rec *) ap_sub_req_method_uri(const char *method,
                                                const char *new_uri,
                                                const request_rec *r,
                                                ap_filter_t *next_filter)
{
    request_rec *rnew;
    /* Initialise res, to avoid a gcc warning */
    int res = HTTP_INTERNAL_SERVER_ERROR;
    char *udir;

    rnew = make_sub_request(r, next_filter);

    /* would be nicer to pass &quot;method&quot; to ap_set_sub_req_protocol */
    rnew-&gt;method = method;
    rnew-&gt;method_number = ap_method_number_of(method);

    if (new_uri[0] == &#039;/&#039;) {
        ap_parse_uri(rnew, new_uri);
    }
    else {
        udir = ap_make_dirstr_parent(rnew-&gt;pool, r-&gt;uri);
        udir = ap_escape_uri(rnew-&gt;pool, udir);    /* re-escape it */
        ap_parse_uri(rnew, ap_make_full_path(rnew-&gt;pool, udir, new_uri));
    }

    /* We cannot return NULL without violating the API. So just turn this
     * subrequest into a 500 to indicate the failure. */
    if (ap_is_recursion_limit_exceeded(r)) {
        rnew-&gt;status = HTTP_INTERNAL_SERVER_ERROR;
        return rnew;
    }

    /* lookup_uri
     * If the content can be served by the quick_handler, we can
     * safely bypass request_internal processing.
     *
     * If next_filter is NULL we are expecting to be
     * internal_fast_redirect&#039;ed to the subrequest, or the subrequest will
     * never be invoked. We need to make sure that the quickhandler is not
     * invoked by any lookups. Since an internal_fast_redirect will always
     * occur too late for the quickhandler to handle the request.
     */
    if (next_filter) {
        res = ap_run_quick_handler(rnew, 1);
    }

    if (next_filter == NULL || res != OK) {
        if ((res = ap_process_request_internal(rnew))) {
            rnew-&gt;status = res;
        }
    }

    return rnew;
}

AP_DECLARE(request_rec *) ap_sub_req_lookup_uri(const char *new_uri,
                                                const request_rec *r,
                                                ap_filter_t *next_filter)
{
    return ap_sub_req_method_uri(&quot;GET&quot;, new_uri, r, next_filter);
}

AP_DECLARE(request_rec *) ap_sub_req_lookup_dirent(const apr_finfo_t *dirent,
                                                   const request_rec *r,
                                                   int subtype,
                                                   ap_filter_t *next_filter)
{
    request_rec *rnew;
    int res;
    char *fdir;
    char *udir;

    rnew = make_sub_request(r, next_filter);

    /* Special case: we are looking at a relative lookup in the same directory.
     * This is 100% safe, since dirent-&gt;name just came from the filesystem.
     */
    if (r-&gt;path_info &amp;&amp; *r-&gt;path_info) {
        /* strip path_info off the end of the uri to keep it in sync
         * with r-&gt;filename, which has already been stripped by directory_walk,
         * merge the dirent-&gt;name, and then, if the caller wants us to remerge
         * the original path info, do so.  Note we never fix the path_info back
         * to r-&gt;filename, since dir_walk would do so (but we don&#039;t expect it
         * to happen in the usual cases)
         */
        udir = apr_pstrdup(rnew-&gt;pool, r-&gt;uri);
        udir[ap_find_path_info(udir, r-&gt;path_info)] = &#039;\0&#039;;
        udir = ap_make_dirstr_parent(rnew-&gt;pool, udir);

        rnew-&gt;uri = ap_make_full_path(rnew-&gt;pool, udir, dirent-&gt;name);
        if (subtype == AP_SUBREQ_MERGE_ARGS) {
            rnew-&gt;uri = ap_make_full_path(rnew-&gt;pool, rnew-&gt;uri, r-&gt;path_info + 1);
            rnew-&gt;path_info = apr_pstrdup(rnew-&gt;pool, r-&gt;path_info);
        }
        rnew-&gt;uri = ap_escape_uri(rnew-&gt;pool, rnew-&gt;uri);
    }
    else {
        udir = ap_make_dirstr_parent(rnew-&gt;pool, r-&gt;uri);
        rnew-&gt;uri = ap_escape_uri(rnew-&gt;pool, ap_make_full_path(rnew-&gt;pool,
                                                                udir,
                                                                dirent-&gt;name));
    }

    fdir = ap_make_dirstr_parent(rnew-&gt;pool, r-&gt;filename);
    rnew-&gt;filename = ap_make_full_path(rnew-&gt;pool, fdir, dirent-&gt;name);
    if (r-&gt;canonical_filename == r-&gt;filename) {
        rnew-&gt;canonical_filename = rnew-&gt;filename;
    }

    /* XXX This is now less relevant; we will do a full location walk
     * these days for this case.  Preserve the apr_stat results, and
     * perhaps we also tag that symlinks were tested and/or found for
     * r-&gt;filename.
     */
    rnew-&gt;per_dir_config = r-&gt;server-&gt;lookup_defaults;

    if ((dirent-&gt;valid &amp; APR_FINFO_MIN) != APR_FINFO_MIN) {
        /*
         * apr_dir_read isn&#039;t very complete on this platform, so
         * we need another apr_stat (with or without APR_FINFO_LINK
         * depending on whether we allow all symlinks here.)  If this
         * is an APR_LNK that resolves to an APR_DIR, then we will rerun
         * everything anyways... this should be safe.
         */
        apr_status_t rv;
        if (ap_allow_options(rnew) &amp; OPT_SYM_LINKS) {
            if (((rv = apr_stat(&amp;rnew-&gt;finfo, rnew-&gt;filename,
                                APR_FINFO_MIN, rnew-&gt;pool)) != APR_SUCCESS)
                &amp;&amp; (rv != APR_INCOMPLETE)) {
                rnew-&gt;finfo.filetype = APR_NOFILE;
            }
        }
        else {
            if (((rv = apr_stat(&amp;rnew-&gt;finfo, rnew-&gt;filename,
                                APR_FINFO_LINK | APR_FINFO_MIN,
                                rnew-&gt;pool)) != APR_SUCCESS)
                &amp;&amp; (rv != APR_INCOMPLETE)) {
                rnew-&gt;finfo.filetype = APR_NOFILE;
            }
        }
    }
    else {
        memcpy(&amp;rnew-&gt;finfo, dirent, sizeof(apr_finfo_t));
    }

    if (rnew-&gt;finfo.filetype == APR_LNK) {
        /*
         * Resolve this symlink.  We should tie this back to dir_walk&#039;s cache
         */
        if ((res = resolve_symlink(rnew-&gt;filename, &amp;rnew-&gt;finfo,
                                   ap_allow_options(rnew), rnew-&gt;pool))
            != OK) {
            rnew-&gt;status = res;
            return rnew;
        }
    }

    if (rnew-&gt;finfo.filetype == APR_DIR) {
        /* ap_make_full_path overallocated the buffers
         * by one character to help us out here.
         */
        strcat(rnew-&gt;filename, &quot;/&quot;);
        if (!rnew-&gt;path_info || !*rnew-&gt;path_info) {
            strcat(rnew-&gt;uri, &quot;/&quot;);
        }
    }

    /* fill in parsed_uri values
     */
    if (r-&gt;args &amp;&amp; *r-&gt;args &amp;&amp; (subtype == AP_SUBREQ_MERGE_ARGS)) {
        ap_parse_uri(rnew, apr_pstrcat(r-&gt;pool, rnew-&gt;uri, &quot;?&quot;,
                                       r-&gt;args, NULL));
    }
    else {
        ap_parse_uri(rnew, rnew-&gt;uri);
    }

    /* We cannot return NULL without violating the API. So just turn this
     * subrequest into a 500. */
    if (ap_is_recursion_limit_exceeded(r)) {
        rnew-&gt;status = HTTP_INTERNAL_SERVER_ERROR;
        return rnew;
    }

    if ((res = ap_process_request_internal(rnew))) {
        rnew-&gt;status = res;
    }

    return rnew;
}

AP_DECLARE(request_rec *) ap_sub_req_lookup_file(const char *new_file,
                                                 const request_rec *r,
                                                 ap_filter_t *next_filter)
{
    request_rec *rnew;
    int res;
    char *fdir;
    apr_size_t fdirlen;

    rnew = make_sub_request(r, next_filter);

    fdir = ap_make_dirstr_parent(rnew-&gt;pool, r-&gt;filename);
    fdirlen = strlen(fdir);

    /* Translate r-&gt;filename, if it was canonical, it stays canonical
     */
    if (r-&gt;canonical_filename == r-&gt;filename) {
        rnew-&gt;canonical_filename = (char*)(1);
    }

    if (apr_filepath_merge(&amp;rnew-&gt;filename, fdir, new_file,
                           APR_FILEPATH_TRUENAME, rnew-&gt;pool) != APR_SUCCESS) {
        rnew-&gt;status = HTTP_FORBIDDEN;
        return rnew;
    }

    if (rnew-&gt;canonical_filename) {
        rnew-&gt;canonical_filename = rnew-&gt;filename;
    }

    /*
     * Check for a special case... if there are no &#039;/&#039; characters in new_file
     * at all, and the path was the same, then we are looking at a relative
     * lookup in the same directory.  Fixup the URI to match.
     */

    if (strncmp(rnew-&gt;filename, fdir, fdirlen) == 0
        &amp;&amp; rnew-&gt;filename[fdirlen]
        &amp;&amp; ap_strchr_c(rnew-&gt;filename + fdirlen, &#039;/&#039;) == NULL) {
        apr_status_t rv;
        if (ap_allow_options(rnew) &amp; OPT_SYM_LINKS) {
            if (((rv = apr_stat(&amp;rnew-&gt;finfo, rnew-&gt;filename,
                                APR_FINFO_MIN, rnew-&gt;pool)) != APR_SUCCESS)
                &amp;&amp; (rv != APR_INCOMPLETE)) {
                rnew-&gt;finfo.filetype = APR_NOFILE;
            }
        }
        else {
            if (((rv = apr_stat(&amp;rnew-&gt;finfo, rnew-&gt;filename,
                                APR_FINFO_LINK | APR_FINFO_MIN,
                                rnew-&gt;pool)) != APR_SUCCESS)
                &amp;&amp; (rv != APR_INCOMPLETE)) {
                rnew-&gt;finfo.filetype = APR_NOFILE;
            }
        }

        if (r-&gt;uri &amp;&amp; *r-&gt;uri) {
            char *udir = ap_make_dirstr_parent(rnew-&gt;pool, r-&gt;uri);
            rnew-&gt;uri = ap_make_full_path(rnew-&gt;pool, udir,
                                          rnew-&gt;filename + fdirlen);
            ap_parse_uri(rnew, rnew-&gt;uri);    /* fill in parsed_uri values */
        }
        else {
            ap_parse_uri(rnew, new_file);        /* fill in parsed_uri values */
            rnew-&gt;uri = apr_pstrdup(rnew-&gt;pool, &quot;&quot;);
        }
    }
    else {
        /* XXX: @@@: What should be done with the parsed_uri values?
         * We would be better off stripping down to the &#039;common&#039; elements
         * of the path, then reassembling the URI as best as we can.
         */
        ap_parse_uri(rnew, new_file);        /* fill in parsed_uri values */
        /*
         * XXX: this should be set properly like it is in the same-dir case
         * but it&#039;s actually sometimes to impossible to do it... because the
         * file may not have a uri associated with it -djg
         */
        rnew-&gt;uri = apr_pstrdup(rnew-&gt;pool, &quot;&quot;);
    }

    /* We cannot return NULL without violating the API. So just turn this
     * subrequest into a 500. */
    if (ap_is_recursion_limit_exceeded(r)) {
        rnew-&gt;status = HTTP_INTERNAL_SERVER_ERROR;
        return rnew;
    }

    if ((res = ap_process_request_internal(rnew))) {
        rnew-&gt;status = res;
    }

    return rnew;
}

AP_DECLARE(int) ap_run_sub_req(request_rec *r)
{
    int retval = DECLINED;
    /* Run the quick handler if the subrequest is not a dirent or file
     * subrequest
     */
    if (!(r-&gt;filename &amp;&amp; r-&gt;finfo.filetype != APR_NOFILE)) {
        retval = ap_run_quick_handler(r, 0);
    }
    if (retval != OK) {
        retval = ap_invoke_handler(r);
        if (retval == DONE) {
            retval = OK;
        }
    }
    ap_finalize_sub_req_protocol(r);
    return retval;
}

AP_DECLARE(void) ap_destroy_sub_req(request_rec *r)
{
    /* Reclaim the space */
    apr_pool_destroy(r-&gt;pool);
}

/*
 * Function to set the r-&gt;mtime field to the specified value if it&#039;s later
 * than what&#039;s already there.
 */
AP_DECLARE(void) ap_update_mtime(request_rec *r, apr_time_t dependency_mtime)
{
    if (r-&gt;mtime &lt; dependency_mtime) {
        r-&gt;mtime = dependency_mtime;
    }
}

/*
 * Is it the initial main request, which we only get *once* per HTTP request?
 */
AP_DECLARE(int) ap_is_initial_req(request_rec *r)
{
    return (r-&gt;main == NULL)       /* otherwise, this is a sub-request */
           &amp;&amp; (r-&gt;prev == NULL);   /* otherwise, this is an internal redirect */
}

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