/* 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 "License"); 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 "AS IS" 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.

 */

/*

 * mod_dir.c: handle default index files, and trailing-/ redirects

 */

#include "apr_strings.h"

#include "apr_lib.h"

#include "ap_config.h"

#include "httpd.h"

#include "http_config.h"

#include "http_core.h"

#include "http_request.h"

#include "http_protocol.h"

#include "http_log.h"

#include "http_main.h"

#include "util_script.h"

#include "mod_rewrite.h"

module AP_MODULE_DECLARE_DATA dir_module;

typedef enum {

    MODDIR_OFF = 0,

    MODDIR_ON,

    MODDIR_UNSET

} moddir_cfg;

#define REDIRECT_OFF   0

#define REDIRECT_UNSET 1

typedef struct dir_config_struct {

    apr_array_header_t *index_names;

    moddir_cfg do_slash;

    moddir_cfg checkhandler;

    int redirect_index;

    const char *dflt;

} dir_config_rec;

#define DIR_CMD_PERMS OR_INDEXES

static const char *add_index(cmd_parms *cmd, void *dummy, const char *arg)

{

    dir_config_rec *d = dummy;

    const char *t, *w;

    int count = 0;

    if (!d->index_names) {

        d->index_names = apr_array_make(cmd->pool, 2, sizeof(char *));

    }

    t = arg;

    while ((w = ap_getword_conf(cmd->pool, &t)) && w[0]) {

        if (count == 0 && !strcasecmp(w, "disabled")) {

            /* peek to see if "disabled" is first in a series of arguments */

            const char *tt = t;

            const char *ww = ap_getword_conf(cmd->temp_pool, &tt;;

            if (ww[0] == '\0') {

               /* "disabled" is first, and alone */

               apr_array_clear(d->index_names); 

               break;

            }

        }

        *(const char **)apr_array_push(d->index_names) = w;

        count++;

    }

    return NULL;

}

static const char *configure_slash(cmd_parms *cmd, void *d_, int arg)

{

    dir_config_rec *d = d_;

    d->do_slash = arg ? MODDIR_ON : MODDIR_OFF;

    return NULL;

}

static const char *configure_checkhandler(cmd_parms *cmd, void *d_, int arg)

{

    dir_config_rec *d = d_;

    d->checkhandler = arg ? MODDIR_ON : MODDIR_OFF;

    return NULL;

}

static const char *configure_redirect(cmd_parms *cmd, void *d_, const char *arg1)

{

    dir_config_rec *d = d_;

    int status;

    if (!strcasecmp(arg1, "ON"))

        status = HTTP_MOVED_TEMPORARILY;

    else if (!strcasecmp(arg1, "OFF"))

        status = REDIRECT_OFF;

    else if (!strcasecmp(arg1, "permanent"))

        status = HTTP_MOVED_PERMANENTLY;

    else if (!strcasecmp(arg1, "temp"))

        status = HTTP_MOVED_TEMPORARILY;

    else if (!strcasecmp(arg1, "seeother"))

        status = HTTP_SEE_OTHER;

    else if (apr_isdigit(*arg1)) {

        status = atoi(arg1);

        if (!ap_is_HTTP_REDIRECT(status)) {

            return "DirectoryIndexRedirect only accepts values between 300 and 399";

        }

    }

    else {

        return "DirectoryIndexRedirect ON|OFF|permanent|temp|seeother|3xx";

    }

    d->redirect_index = status;

    return NULL;

}

static const command_rec dir_cmds[] =

{

    AP_INIT_TAKE1("FallbackResource", ap_set_string_slot,

                  (void*)APR_OFFSETOF(dir_config_rec, dflt),

                  DIR_CMD_PERMS, "Set a default handler"),

    AP_INIT_RAW_ARGS("DirectoryIndex", add_index, NULL, DIR_CMD_PERMS,

                    "a list of file names"),

    AP_INIT_FLAG("DirectorySlash", configure_slash, NULL, DIR_CMD_PERMS,

                 "On or Off"),

    AP_INIT_FLAG("DirectoryCheckHandler", configure_checkhandler, NULL, DIR_CMD_PERMS,

                 "On or Off"),

    AP_INIT_TAKE1("DirectoryIndexRedirect", configure_redirect,

                   NULL, DIR_CMD_PERMS, "On, Off, or a 3xx status code."),

    {NULL}

};

static void *create_dir_config(apr_pool_t *p, char *dummy)

{

    dir_config_rec *new = apr_pcalloc(p, sizeof(dir_config_rec));

    new->index_names = NULL;

    new->do_slash = MODDIR_UNSET;

    new->checkhandler = MODDIR_UNSET;

    new->redirect_index = REDIRECT_UNSET;

    return (void *) new;

}

static void *merge_dir_configs(apr_pool_t *p, void *basev, void *addv)

{

    dir_config_rec *new = apr_pcalloc(p, sizeof(dir_config_rec));

    dir_config_rec *base = (dir_config_rec *)basev;

    dir_config_rec *add = (dir_config_rec *)addv;

    new->index_names = add->index_names ? add->index_names : base->index_names;

    new->do_slash =

        (add->do_slash == MODDIR_UNSET) ? base->do_slash : add->do_slash;

    new->checkhandler =

        (add->checkhandler == MODDIR_UNSET) ? base->checkhandler : add->checkhandler;

    new->redirect_index=

        (add->redirect_index == REDIRECT_UNSET) ? base->redirect_index : add->redirect_index;

    new->dflt = add->dflt ? add->dflt : base->dflt;

    return new;

}

static int fixup_dflt(request_rec *r)

{

    dir_config_rec *d = ap_get_module_config(r->per_dir_config, &dir_module);

    const char *name_ptr;

    request_rec *rr;

    int error_notfound = 0;

    name_ptr = d->dflt;

    if ((name_ptr == NULL) || !(strcasecmp(name_ptr,"disabled"))){

        return DECLINED;

    }

    /* XXX: if FallbackResource points to something that doesn't exist,

     * this may recurse until it hits the limit for internal redirects

     * before returning an Internal Server Error.

     */

    /* The logic of this function is basically cloned and simplified

     * from fixup_dir below.  See the comments there.

     */

    if (r->args != NULL) {

        name_ptr = apr_pstrcat(r->pool, name_ptr, "?", r->args, NULL);

    }

    rr = ap_sub_req_lookup_uri(name_ptr, r, r->output_filters);

    if (rr->status == HTTP_OK

        && (   (rr->handler && !strcmp(rr->handler, "proxy-server"))

            || rr->finfo.filetype == APR_REG)) {

        ap_internal_fast_redirect(rr, r);

        return OK;

    }

    else if (ap_is_HTTP_REDIRECT(rr->status)) {

        apr_pool_join(r->pool, rr->pool);

        r->notes = apr_table_overlay(r->pool, r->notes, rr->notes);

        r->headers_out = apr_table_overlay(r->pool, r->headers_out,

                                           rr->headers_out);

        r->err_headers_out = apr_table_overlay(r->pool, r->err_headers_out,

                                               rr->err_headers_out);

        error_notfound = rr->status;

    }

    else if (rr->status && rr->status != HTTP_NOT_FOUND

             && rr->status != HTTP_OK) {

        error_notfound = rr->status;

    }

    ap_destroy_sub_req(rr);

    if (error_notfound) {

        return error_notfound;

    }

    /* nothing for us to do, pass on through */

    return DECLINED;

}

static int fixup_dir(request_rec *r)

{

    dir_config_rec *d;

    char *dummy_ptr[1];

    char **names_ptr;

    int num_names;

    int error_notfound = 0;

    /* In case mod_mime wasn't present, and no handler was assigned. */

    if (!r->handler) {

        r->handler = DIR_MAGIC_TYPE;

    }

    /* Never tolerate path_info on dir requests */

    if (r->path_info && *r->path_info) {

        return DECLINED;

    }

    d = (dir_config_rec *)ap_get_module_config(r->per_dir_config,

                                               &dir_module);

    /* Redirect requests that are not '/' terminated */

    if (r->uri[0] == '\0' || r->uri[strlen(r->uri) - 1] != '/')

    {

        char *ifile;

        if (!d->do_slash) {

            return DECLINED;

        }

        /* Only redirect non-get requests if we have no note to warn

         * that this browser cannot handle redirs on non-GET requests

         * (such as Microsoft's WebFolders).

         */

        if ((r->method_number != M_GET)

                && apr_table_get(r->subprocess_env, "redirect-carefully")) {

            return DECLINED;

        }

        if (r->args != NULL) {

            ifile = apr_pstrcat(r->pool, ap_escape_uri(r->pool, r->uri),

                                "/?", r->args, NULL);

        }

        else {

            ifile = apr_pstrcat(r->pool, ap_escape_uri(r->pool, r->uri),

                                "/", NULL);

        }

        apr_table_setn(r->headers_out, "Location",

                       ap_construct_url(r->pool, ifile, r));

        return HTTP_MOVED_PERMANENTLY;

    }

    /* we're running between mod_rewrites fixup and its internal redirect handler, step aside */

    if (!strcmp(r->handler, REWRITE_REDIRECT_HANDLER_NAME)) { 

        /* Prevent DIR_MAGIC_TYPE from leaking out when someone has taken over */

        if (!strcmp(r->content_type, DIR_MAGIC_TYPE)) { 

            r->content_type = NULL;

        }

        return DECLINED;

    }

    if (d->checkhandler == MODDIR_ON && strcmp(r->handler, DIR_MAGIC_TYPE)) {

        /* Prevent DIR_MAGIC_TYPE from leaking out when someone has taken over */

        if (!strcmp(r->content_type, DIR_MAGIC_TYPE)) { 

            r->content_type = NULL;

        }

        return DECLINED;

    }

    if (d->index_names) {

        names_ptr = (char **)d->index_names->elts;

        num_names = d->index_names->nelts;

    }

    else {

        dummy_ptr[0] = AP_DEFAULT_INDEX;

        names_ptr = dummy_ptr;

        num_names = 1;

    }

    for (; num_names; ++names_ptr, --num_names) {

        /* XXX: Is this name_ptr considered escaped yet, or not??? */

        char *name_ptr = *names_ptr;

        request_rec *rr;

        /* Once upon a time args were handled _after_ the successful redirect.

         * But that redirect might then _refuse_ the given r->args, creating

         * a nasty tangle.  It seems safer to consider the r->args while we

         * determine if name_ptr is our viable index, and therefore set them

         * up correctly on redirect.

         */

        if (r->args != NULL) {

            name_ptr = apr_pstrcat(r->pool, name_ptr, "?", r->args, NULL);

        }

        rr = ap_sub_req_lookup_uri(name_ptr, r, r->output_filters);

        /* The sub request lookup is very liberal, and the core map_to_storage

         * handler will almost always result in HTTP_OK as /foo/index.html

         * may be /foo with PATH_INFO="/index.html", or even / with

         * PATH_INFO="/foo/index.html". To get around this we insist that the

         * the index be a regular filetype.

         *

         * Another reason is that the core handler also makes the assumption

         * that if r->finfo is still NULL by the time it gets called, the

         * file does not exist.

         */

        if (rr->status == HTTP_OK

            && (   (rr->handler && !strcmp(rr->handler, "proxy-server"))

                || rr->finfo.filetype == APR_REG)) {

            if (ap_is_HTTP_REDIRECT(d->redirect_index)) {

                apr_table_setn(r->headers_out, "Location", ap_construct_url(r->pool, rr->uri, r));

                return d->redirect_index;

            }

            ap_internal_fast_redirect(rr, r);

            return OK;

        }

        /* If the request returned a redirect, propagate it to the client */

        if (ap_is_HTTP_REDIRECT(rr->status)

            || (rr->status == HTTP_NOT_ACCEPTABLE && num_names == 1)

            || (rr->status == HTTP_UNAUTHORIZED && num_names == 1)) {

            apr_pool_join(r->pool, rr->pool);

            error_notfound = rr->status;

            r->notes = apr_table_overlay(r->pool, r->notes, rr->notes);

            r->headers_out = apr_table_overlay(r->pool, r->headers_out,

                                               rr->headers_out);

            r->err_headers_out = apr_table_overlay(r->pool, r->err_headers_out,

                                                   rr->err_headers_out);

            return error_notfound;

        }

        /* If the request returned something other than 404 (or 200),

         * it means the module encountered some sort of problem. To be

         * secure, we should return the error, rather than allow autoindex

         * to create a (possibly unsafe) directory index.

         *

         * So we store the error, and if none of the listed files

         * exist, we return the last error response we got, instead

         * of a directory listing.

         */

        if (rr->status && rr->status != HTTP_NOT_FOUND

                && rr->status != HTTP_OK) {

            error_notfound = rr->status;

        }

        ap_destroy_sub_req(rr);

    }

    if (error_notfound) {

        return error_notfound;

    }

    /* record what we tried, mostly for the benefit of mod_autoindex */

    apr_table_setn(r->notes, "dir-index-names",

                   d->index_names ?

                       apr_array_pstrcat(r->pool, d->index_names, ',') :

                       AP_DEFAULT_INDEX);

    /* nothing for us to do, pass on through */

    return DECLINED;

}

static int dir_fixups(request_rec *r)

{

    if (r->finfo.filetype == APR_DIR) {

        /* serve up a directory */

        return fixup_dir(r);

    }

    else if ((r->finfo.filetype == APR_NOFILE) && (r->handler == NULL)) {

        /* No handler and nothing in the filesystem - use fallback */

        return fixup_dflt(r);

    }

    return DECLINED;

}

static void register_hooks(apr_pool_t *p)

{

    ap_hook_fixups(dir_fixups,NULL,NULL,APR_HOOK_LAST);

}

AP_DECLARE_MODULE(dir) = {

    STANDARD20_MODULE_STUFF,

    create_dir_config,          /* create per-directory config structure */

    merge_dir_configs,          /* merge per-directory config structures */

    NULL,                       /* create per-server config structure */

    NULL,                       /* merge per-server config structures */

    dir_cmds,                   /* command apr_table_t */

    register_hooks              /* register hooks */

};