/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing Applications,
 * University of Illinois, Urbana-Champaign.
 */
/*
 * mod_userdir... implement the UserDir command.  Broken away from the
 * Alias stuff for a couple of good and not-so-good reasons:
 *
 * 1) It shows a real minimal working example of how to do something like
 *    this.
 * 2) I know people who are actually interested in changing this *particular*
 *    aspect of server functionality without changing the rest of it.  That's
 *    what this whole modular arrangement is supposed to be good at...
 *
 * Modified by Alexei Kosut to support the following constructs
 * (server running at www.foo.com, request for /~bar/one/two.html)
 *
 * UserDir public_html      -> ~bar/public_html/one/two.html
 * UserDir /usr/web         -> /usr/web/bar/one/two.html
 * UserDir /home/ * /www     -> /home/bar/www/one/two.html
 *  NOTE: theses ^ ^ space only added allow it to work in a comment, ignore
 * UserDir http://x/users   -> (302) http://x/users/bar/one/two.html
 * UserDir http://x/ * /y     -> (302) http://x/bar/y/one/two.html
 *  NOTE: here also ^ ^
 *
 * In addition, you can use multiple entries, to specify alternate
 * user directories (a la Directory Index). For example:
 *
 * UserDir public_html /usr/web http://www.xyz.com/users
 *
 * Modified by Ken Coar to provide for the following:
 *
 * UserDir disable[d] username ...
 * UserDir enable[d] username ...
 *
 * If "disabled" has no other arguments, *all* ~<username> references are
 * disabled, except those explicitly turned on with the "enabled" keyword.
 */
#include "httpd.h"
#include "http_config.h"
module userdir_module;
typedef struct userdir_config {
    int globally_disabled;
    char *userdir;
    table *enabled_users;
    table *disabled_users;
}              userdir_config;
/*
 * Server config for this module: global disablement flag, a list of usernames
 * ineligible for UserDir access, a list of those immune to global (but not
 * explicit) disablement, and the replacement string for all others.
 */
static void *create_userdir_config(pool *p, server_rec *s)
{
    userdir_config
    * newcfg = (userdir_config *) ap_pcalloc(p, sizeof(userdir_config));
    newcfg->globally_disabled = 0;
    newcfg->userdir = DEFAULT_USER_DIR;
    newcfg->enabled_users = ap_make_table(p, 4);
    newcfg->disabled_users = ap_make_table(p, 4);
    return (void *) newcfg;
}
#define O_DEFAULT 0
#define O_ENABLE 1
#define O_DISABLE 2
static const char *set_user_dir(cmd_parms *cmd, void *dummy, char *arg)
{
    userdir_config
    * s_cfg = (userdir_config *) ap_get_module_config
    (
     cmd->server->module_config,
     &userdir_module
    );
    char *username;
    const char
        *usernames = arg;
    char *kw = ap_getword_conf(cmd->pool, &usernames);
    table *usertable;
    /*
     * Let's do the comparisons once.
     */
    if ((!strcasecmp(kw, "disable")) || (!strcasecmp(kw, "disabled"))) {
        /*
         * If there are no usernames specified, this is a global disable - we
         * need do no more at this point than record the fact.
         */
        if (strlen(usernames) == 0) {
            s_cfg->globally_disabled = 1;
            return NULL;
        }
        usertable = s_cfg->disabled_users;
    }
    else if ((!strcasecmp(kw, "enable")) || (!strcasecmp(kw, "enabled"))) {
        /*
         * The "disable" keyword can stand alone or take a list of names, but
         * the "enable" keyword requires the list.  Whinge if it doesn't have
         * it.
         */
        if (strlen(usernames) == 0) {
            return "UserDir \"enable\" keyword requires a list of usernames";
        }
        usertable = s_cfg->enabled_users;
    }
    else {
        /*
         * If the first (only?) value isn't one of our keywords, look at each
         * config 'word' for validity and copy the entire arg to the userdir 
         * if all paths are valid.
         */
        const char *userdirs = arg;
        while (*userdirs) {
            char *thisdir = ap_getword_conf(cmd->pool, &userdirs);
            if (!ap_os_is_path_absolute(thisdir) && !strchr(thisdir, ':'))
#if defined(WIN32) || defined(NETWARE)
                return "UserDir must specify an absolute redirect "
                       "or absolute file path";
#else
                if (strchr(thisdir, '*'))
                     return "UserDir cannot specify '*' substitution within "
                            "a relative path";
#endif
        }
        s_cfg->userdir = ap_pstrdup(cmd->pool, arg);
#if defined(WIN32) || defined(OS2) || defined(NETWARE)
        /* These are incomplete paths, so we cannot canonicalize them yet.
         * but any backslashes will confuse the parser, later, so simply
         * change them to slash form.
         */
        arg = s_cfg->userdir;
        while (arg = strchr(arg, '\\'))
            *(arg++) = '/';
#endif
        return NULL;
    }
    /*
     * Now we just take each word in turn from the command line and add it to
     * the appropriate table.
     */
    while (*usernames) {
        username = ap_getword_conf(cmd->pool, &usernames);
        ap_table_setn(usertable, username, kw);
    }
    return NULL;
}
static const command_rec userdir_cmds[] = {
    {"UserDir", set_user_dir, NULL, RSRC_CONF, RAW_ARGS,
    "the public subdirectory in users' home directories, or 'disabled', or 'disabled username username...', or 'enabled username username...'"},
    {NULL}
};
static int translate_userdir(request_rec *r)
{
    void *server_conf = r->server->module_config;
    const userdir_config *s_cfg =
    (userdir_config *) ap_get_module_config(server_conf, &userdir_module);
    char *name = r->uri;
    const char *userdirs = s_cfg->userdir;
    const char *w, *dname;
    char *redirect;
    struct stat statbuf;
    /*
     * If the URI doesn't match our basic pattern, we've nothing to do with
     * it.
     */
    if (
        (s_cfg->userdir == NULL) ||
        (name[0] != '/') ||
        (name[1] != '~')
        ) {
        return DECLINED;
    }
    dname = name + 2;
    w = ap_getword(r->pool, &dname, '/');
    /*
     * The 'dname' funny business involves backing it up to capture the '/'
     * delimiting the "/~user" part from the rest of the URL, in case there
     * was one (the case where there wasn't being just "GET /~user HTTP/1.0",
     * for which we don't want to tack on a '/' onto the filename).
     */
    if (dname[-1] == '/') {
        --dname;
    }
    /*
     * If there's no username, it's not for us.  Ignore . and .. as well.
     */
    if (w[0] == '\0' || (w[1] == '.' && (w[2] == '\0' || (w[2] == '.' && w[3] == '\0')))) {
        return DECLINED;
    }
    /*
     * Nor if there's an username but it's in the disabled list.
     */
    if (ap_table_get(s_cfg->disabled_users, w) != NULL) {
        return DECLINED;
    }
    /*
     * If there's a global interdiction on UserDirs, check to see if this
     * name is one of the Blessed.
     */
    if (
        s_cfg->globally_disabled &&
        (ap_table_get(s_cfg->enabled_users, w) == NULL)
        ) {
        return DECLINED;
    }
    /*
     * Special cases all checked, onward to normal substitution processing.
     */
    while (*userdirs) {
        const char *userdir = ap_getword_conf(r->pool, &userdirs);
        char *filename = NULL;
        int is_absolute = ap_os_is_path_absolute(userdir);
        if (strchr(userdir, '*')) {
            /* token '*' embedded:
             */
            char *x = ap_getword(r->pool, &userdir, '*');
            if (is_absolute) {
                /* token '*' within absolute path
                 * serves [UserDir arg-pre*][user][UserDir arg-post*]
                 * /somepath/ * /somedir + /~smith -> /somepath/smith/somedir
                 */
                filename = ap_pstrcat(r->pool, x, w, userdir, NULL);
            }
            else if (strchr(x, ':')) {
                /* token '*' within a redirect path
                 * serves [UserDir arg-pre*][user][UserDir arg-post*]
                 * http://server/user/ * + /~smith/foo -> http://server/user/smith/foo
                 */
                redirect = ap_pstrcat(r->pool, x, w, userdir, dname, NULL);
                ap_table_setn(r->headers_out, "Location", redirect);
                return REDIRECT;
            }
            else {
                /* Not a redirect, not an absolute path, '*' token:
                 * serves [homedir]/[UserDir arg]
                 * something/ * /public_html
                 * Shouldn't happen, we trap for this in set_user_dir
                 */
                return DECLINED;
            }
        }
        else if (is_absolute) {
            /* An absolute path, no * token:
             * serves [UserDir arg]/[user]
             * /home + /~smith -> /home/smith
             */
            if (userdir[strlen(userdir) - 1] == '/')
                filename = ap_pstrcat(r->pool, userdir, w, NULL);
            else
                filename = ap_pstrcat(r->pool, userdir, "/", w, NULL);
        }
        else if (strchr(userdir, ':')) {
            /* A redirect, not an absolute path, no * token:
             * serves [UserDir arg]/[user][dname]
             * http://server/ + /~smith/foo -> http://server/smith/foo
             */
            if (userdir[strlen(userdir) - 1] == '/')
                redirect = ap_pstrcat(r->pool, userdir, w, dname, NULL);
            else
                redirect = ap_pstrcat(r->pool, userdir, "/", w, dname, NULL);
            ap_table_setn(r->headers_out, "Location", redirect);
            return REDIRECT;
        }
        else {
            /* Not a redirect, not an absolute path, no * token:
             * serves [homedir]/[UserDir arg]
             * e.g. /~smith -> /home/smith/public_html
             */
#if defined(WIN32) || defined(NETWARE)
            /* Need to figure out home dirs on NT and NetWare 
             * Shouldn't happen here, though, we trap for this in set_user_dir
             */
            return DECLINED;
#else                           /* WIN32 & NetWare */
            struct passwd *pw;
            if ((pw = getpwnam(w))) {
#ifdef OS2
                /* Need to manually add user name for OS/2 */
                filename = ap_pstrcat(r->pool, pw->pw_dir, w, "/", userdir, NULL);
#else
                filename = ap_pstrcat(r->pool, pw->pw_dir, "/", userdir, NULL);
#endif
            }
#endif                          /* WIN32 & NetWare */
        }
        /*
         * Now see if it exists, or we're at the last entry. If we are at the
         * last entry, then use the filename generated (if there is one)
         * anyway, in the hope that some handler might handle it. This can be
         * used, for example, to run a CGI script for the user.
         */
        if (filename && (!*userdirs || stat(filename, &statbuf) != -1)) {
            r->filename = ap_pstrcat(r->pool, filename, dname, NULL);
            /* when statbuf contains info on r->filename we can save a syscall
             * by copying it to r->finfo
             */
            if (*userdirs && dname[0] == 0)
                r->finfo = statbuf;
            return OK;
        }
    }
    return DECLINED;
}
module userdir_module = {
    STANDARD_MODULE_STUFF,
    NULL,                       /* initializer */
    NULL,                       /* dir config creater */
    NULL,                       /* dir merger --- default is to override */
    create_userdir_config,      /* server config */
    NULL,                       /* merge server config */
    userdir_cmds,               /* command table */
    NULL,                       /* handlers */
    translate_userdir,          /* filename translation */
    NULL,                       /* check_user_id */
    NULL,                       /* check auth */
    NULL,                       /* check access */
    NULL,                       /* type_checker */
    NULL,                       /* fixups */
    NULL,                       /* logger */
    NULL,                       /* header parser */
    NULL,                       /* child_init */
    NULL,                       /* child_exit */
    NULL                        /* post read-request */
};