gophernicus/gophernicus.c

/*
 * Gophernicus
 *
 * Copyright (c) 2009-2018 Kim Holviala <kimholviala@fastmail.com>
 * Copyright (c) 2019 Gophernicus Developers <gophernicus@gophernicus.org>
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 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.
 */


#include "gophernicus.h"


/*
 * Libwrap needs these defined
 */
#ifdef HAVE_LIBWRAP
int allow_severity = LOG_DEBUG;
int deny_severity = LOG_ERR;
#endif


/*
 * Print gopher menu line
 */
void info(state *st, char *str, char type)
{
    char buf[BUFSIZE];
    char selector[16];

    /* Convert string to output charset */
    if (st->opt_iconv) sstrniconv(st->out_charset, buf, str);
    else sstrlcpy(buf, str);

    /* Handle gopher title resources */
    strclear(selector);
    if (type == TYPE_TITLE) {
        sstrlcpy(selector, "TITLE");
        type = TYPE_INFO;
    }

    /* Output info line */
    strcut(buf, st->out_width);
    printf("%c%s\t%s\t%s" CRLF,
        type, buf, selector, DUMMY_HOST);
}


/*
 * Print footer
 */
void footer(state *st)
{
    char line[BUFSIZE];
    char buf[BUFSIZE];
    char msg[BUFSIZE];

    if (!st->opt_footer) {
#ifndef ENABLE_STRICT_RFC1436
        if (st->req_filetype == TYPE_MENU || st->req_filetype == TYPE_QUERY)
#endif
            printf("." CRLF);
        return;
    }

    /* Create horizontal line */
    strrepeat(line, '_', st->out_width);

    /* Create right-aligned footer message */
    snprintf(buf, sizeof(buf), FOOTER_FORMAT, st->server_platform);
    snprintf(msg, sizeof(msg), "%*s", st->out_width - 1, buf);

    /* Menu footer? */
    if (st->req_filetype == TYPE_MENU || st->req_filetype == TYPE_QUERY) {
        info(st, line, TYPE_INFO);
        info(st, msg, TYPE_INFO);
        printf("." CRLF);
    }

    /* Plain text footer */
    else {
        printf("%s" CRLF, line);
        printf("%s" CRLF, msg);
#ifdef ENABLE_STRICT_RFC1436
        printf("." CRLF);
#endif
    }
}


/*
 * Print error message & exit
 */
void die(state *st, char *message, char *description)
{
    int en = errno;
    static const char error_gif[] = ERROR_GIF;

    /* Handle NULL description */
    if (description == NULL) description = strerror(en);

    /* Log the error */
#ifdef HAVE_SYSLOG
    if (st->opt_syslog) {
        syslog(LOG_ERR, "error \"%s\" for request \"%s\" from %s",
            description, st->req_selector, st->req_remote_addr);
    }
#endif
    log_combined(st, HTTP_404);

    /* Handle menu errors */
    if (st->req_filetype == TYPE_MENU || st->req_filetype == TYPE_QUERY) {
        printf("3" ERROR_PREFIX "%s\tTITLE\t" DUMMY_HOST CRLF, message);
        footer(st);
    }

    /* Handle image errors */
    else if (st->req_filetype == TYPE_GIF || st->req_filetype == TYPE_IMAGE) {
        fwrite(error_gif, sizeof(error_gif), 1, stdout);
    }

    /* Handle HTML errors */
    else if (st->req_filetype == TYPE_HTML) {
        printf("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 3.2 Final//EN\">\n"
            "<HTML>\n<HEAD>\n"
            "  <META HTTP-EQUIV=\"Content-Type\" CONTENT=\"text/html;charset=iso-8859-1\">\n"
            "  <TITLE>" ERROR_PREFIX "%1$s</TITLE>\n"
            "</HEAD>\n<BODY>\n"
            "<STRONG>" ERROR_PREFIX "%1$s</STRONG>\n"
            "<PRE>\n", message);
        footer(st);
        printf("</PRE>\n</BODY>\n</HTML>\n");
    }

    /* Use plain text error for other filetypes */
    else {
        printf(ERROR_PREFIX "%s" CRLF, message);
        footer(st);
    }

    /* Quit */
    exit(EXIT_FAILURE);
}


/*
 * Apache-compatible combined logging
 */
void log_combined(state *st, int status)
{
    FILE *fp;
    struct tm *ltime;
    char timestr[64];
    time_t now;

    /* Try to open the logfile for appending */
    if (!*st->log_file) return;
    if ((fp = fopen(st->log_file , "a")) == NULL) return;

    /* Format time */
    now = time(NULL);
    ltime = localtime(&now);
    strftime(timestr, sizeof(timestr), HTTP_DATE, ltime);

    /* Generate log entry */
    fprintf(fp, "%s %s:%i - [%s] \"GET %c%s HTTP/1.0\" %i %li \"%s\" \"" HTTP_USERAGENT "\"\n",
        st->req_remote_addr,
        st->server_host,
        st->server_port,
        timestr,
        st->req_filetype,
        st->req_selector,
        status,
        (long) st->req_filesize,
        st->req_referrer);
    fclose(fp);
}


/*
 * Convert gopher selector to an absolute path
 */
void selector_to_path(state *st)
{
    DIR *dp;
    struct dirent *dir;
    struct stat file;
#ifdef HAVE_PASSWD
    struct passwd *pwd;
    char *path = EMPTY;
    char *c;
#endif
    char buf[BUFSIZE];
    int i;

    /* Handle selector rewriting */
    for (i = 0; i < st->rewrite_count; i++) {

        /* Match found? */
        if (strstr(st->req_selector, st->rewrite[i].match) == st->req_selector) {

            /* Replace match with a new string */
            snprintf(buf, sizeof(buf), "%s%s",
                st->rewrite[i].replace,
                st->req_selector + strlen(st->rewrite[i].match));

#ifdef HAVE_SYSLOG
            if (st->debug) {
                syslog(LOG_INFO, "rewriting selector \"%s\" -> \"%s\"",
                    st->req_selector, buf);
            }
#endif

            sstrlcpy(st->req_selector, buf);
        }
    }

#ifdef HAVE_PASSWD
    /* Virtual userdir (~user -> /home/user/public_gopher)? */
    if (st->opt_personal_spaces && *(st->user_dir) &&
        sstrncmp(st->req_selector, "/~") == MATCH) {

        /* Parse userdir login name & path */;
        sstrlcpy(buf, st->req_selector + 2);
        if ((c = strchr(buf, '/'))) {
            *c = '\0';
            path = c + 1;
        }

        /* Check user validity */
        if ((pwd = getpwnam(buf)) == NULL)
            die(st, ERR_NOTFOUND, "User not found");
        if (pwd->pw_uid < PASSWD_MIN_UID)
            die(st, ERR_NOTFOUND, "User found but UID too low");

        /* Generate absolute path to users own gopher root */
        snprintf(st->req_realpath, sizeof(st->req_realpath),
            "%s/%s/%s", pwd->pw_dir, st->user_dir, path);

        /* Check ~public_gopher access rights */
        if (stat(st->req_realpath, &file) == ERROR)
            die(st, ERR_NOTFOUND, NULL);
        if ((file.st_mode & S_IROTH) == 0)
            die(st, ERR_ACCESS, "~/public_gopher not world-readable");
        if (file.st_uid != pwd->pw_uid)
            die(st, ERR_ACCESS, "~/ and ~/public_gopher owned by different users");

        /* Userdirs always come from the default vhost */
        if (st->opt_vhost)
            sstrlcpy(st->server_host, st->server_host_default);
        return;
    }
#endif

    /* Virtual hosting */
    if (st->opt_vhost) {

        /* Try looking for the selector from the current vhost */
        snprintf(st->req_realpath, sizeof(st->req_realpath), "%s/%s%s",
            st->server_root, st->server_host, st->req_selector);
        if (stat(st->req_realpath, &file) == OK) return;

        /* Loop through all vhosts looking for the selector */
        if ((dp = opendir(st->server_root)) == NULL) die(st, ERR_NOTFOUND, NULL);
        while ((dir = readdir(dp))) {

            /* Skip .hidden dirs and . & .. */
            if (dir->d_name[0] == '.') continue;

            /* Special case - skip lost+found (don't ask) */
            if (sstrncmp(dir->d_name, "lost+found") == MATCH) continue;

            /* Generate path to the found vhost */
            snprintf(st->req_realpath, sizeof(st->req_realpath), "%s/%s%s",
                st->server_root, dir->d_name, st->req_selector);

            /* Did we find the selector under this vhost? */
            if (stat(st->req_realpath, &file) == OK) {

                /* Virtual host found - update state & return */
                sstrlcpy(st->server_host, dir->d_name);
                return;
            }
        }
        closedir(dp);
    }

    /* Handle normal selectors */
    snprintf(st->req_realpath, sizeof(st->req_realpath),
        "%s%s", st->server_root, st->req_selector);
}


/*
 * Get local IP address
 */
char *get_local_address(void)
{
#ifndef _WIN32
#ifdef HAVE_IPv4
    struct sockaddr_in addr;
    socklen_t addrsize = sizeof(addr);
#endif
#ifdef HAVE_IPv6
    struct sockaddr_in6 addr6;
    socklen_t addr6size = sizeof(addr6);
    static char address[INET6_ADDRSTRLEN];
#endif
    char *c;

    /* Try IPv4 first */
#ifdef HAVE_IPv4
    if (getsockname(0, (struct sockaddr *) &addr, &addrsize) == OK) {
        c = inet_ntoa(addr.sin_addr);
        if (strlen(c) > 0 && *c != '0') return c;
    }
#endif

    /* IPv4 didn't work - try IPv6 */
#ifdef HAVE_IPv6
    if (getsockname(0, (struct sockaddr *) &addr6, &addr6size) == OK) {
        if (inet_ntop(AF_INET6, &addr6.sin6_addr, address, sizeof(address))) {

            /* Strip ::ffff: IPv4-in-IPv6 prefix */
            if (sstrncmp(address, "::ffff:") == MATCH) return (address + 7);
            else return address;
        }
    }
#endif
#endif

    /* Nothing works... I'm out of ideas */
    return UNKNOWN_ADDR;
}


/*
 * Get remote peer IP address
 */
char *get_peer_address(void)
{
#ifndef _WIN32
#ifdef HAVE_IPv4
    struct sockaddr_in addr;
    socklen_t addrsize = sizeof(addr);
#endif
#ifdef HAVE_IPv6
    struct sockaddr_in6 addr6;
    socklen_t addr6size = sizeof(addr6);
    static char address[INET6_ADDRSTRLEN];
#endif
    char *c;

    /* Are we a CGI script? */
    if ((c = getenv("REMOTE_ADDR"))) return c;
    /* if ((c = getenv("REMOTE_HOST"))) return c; */

    /* Try IPv4 first */
#ifdef HAVE_IPv4
    if (getpeername(0, (struct sockaddr *) &addr, &addrsize) == OK) {
        c = inet_ntoa(addr.sin_addr);
        if (strlen(c) > 0 && *c != '0') return c;
    }
#endif

    /* IPv4 didn't work - try IPv6 */
#ifdef HAVE_IPv6
    if (getpeername(0, (struct sockaddr *) &addr6, &addr6size) == OK) {
        if (inet_ntop(AF_INET6, &addr6.sin6_addr, address, sizeof(address))) {

            /* Strip ::ffff: IPv4-in-IPv6 prefix */
            if (sstrncmp(address, "::ffff:") == MATCH) return (address + 7);
            else return address;
        }
    }
#endif
#endif

    /* Nothing works... I'm out of ideas */
    return UNKNOWN_ADDR;
}


/*
 * Initialize state struct to default/empty values
 */
void init_state(state *st)
{
    static const char *filetypes[] = { FILETYPES };
    char buf[BUFSIZE];
    char *c;
    int i;

    /* Request */
    strclear(st->req_selector);
    strclear(st->req_realpath);
    strclear(st->req_query_string);
    strclear(st->req_search);
    strclear(st->req_referrer);
    sstrlcpy(st->req_local_addr, get_local_address());
    sstrlcpy(st->req_remote_addr, get_peer_address());
    /* strclear(st->req_remote_host); */
    st->req_filetype = DEFAULT_TYPE;
    st->req_protocol = PROTO_GOPHER;
    st->req_filesize = 0;

    /* Output */
    st->out_width = DEFAULT_WIDTH;
    st->out_charset = DEFAULT_CHARSET;

    /* Settings */
    sstrlcpy(st->server_root, DEFAULT_ROOT);
    sstrlcpy(st->server_host_default, DEFAULT_HOST);

    if ((c = getenv("HOSTNAME")))
        sstrlcpy(st->server_host, c);
#ifndef _WIN32
    else if ((gethostname(buf, sizeof(buf))) != ERROR)
        sstrlcpy(st->server_host, buf);
#endif

    st->server_port = DEFAULT_PORT;
    st->server_tls_port = DEFAULT_TLS_PORT;

    st->default_filetype = DEFAULT_TYPE;
    sstrlcpy(st->map_file, DEFAULT_MAP);
    sstrlcpy(st->tag_file, DEFAULT_TAG);
    sstrlcpy(st->cgi_file, DEFAULT_CGI);
    sstrlcpy(st->user_dir, DEFAULT_USERDIR);
    strclear(st->log_file);

    st->hidden_count = 0;
    st->filetype_count = 0;
    strclear(st->filter_dir);
    st->rewrite_count = 0;

    strclear(st->server_description);
    strclear(st->server_location);
    strclear(st->server_platform);
    strclear(st->server_admin);

#ifdef __OpenBSD__
	st->extra_unveil_paths = NULL;
#endif


    /* Session */
    st->session_timeout = DEFAULT_SESSION_TIMEOUT;
    st->session_max_kbytes = DEFAULT_SESSION_MAX_KBYTES;
    st->session_max_hits = DEFAULT_SESSION_MAX_HITS;

    /* Feature options */
    st->opt_vhost = TRUE;
    st->opt_parent = TRUE;
    st->opt_header = TRUE;
    st->opt_footer = TRUE;
    st->opt_date = TRUE;
    st->opt_syslog = TRUE;
    st->opt_magic = TRUE;
    st->opt_iconv = TRUE;
    st->opt_query = TRUE;
    st->opt_caps = TRUE;
    st->opt_status = TRUE;
    st->opt_shm = TRUE;
    st->opt_root = TRUE;
    st->opt_proxy = TRUE;
    st->opt_exec = TRUE;
    st->opt_personal_spaces = TRUE;
    st->debug = FALSE;

    /* Load default suffix -> filetype mappings */
    for (i = 0; filetypes[i]; i += 2) {
        if (st->filetype_count < MAX_FILETYPES) {
            sstrlcpy(st->filetype[st->filetype_count].suffix, filetypes[i]);
            st->filetype[st->filetype_count].type = *filetypes[i + 1];
            st->filetype_count++;
        }
    }
}


/*
 * Main
 */
int main(int argc, char *argv[])
{
    struct stat file;
    state st;
    char self[64];
    char selector[BUFSIZE];
    char buf[BUFSIZE];
    char *dest;
    char *c;
#ifdef HAVE_SHMEM
    struct shmid_ds shm_ds;
    shm_state *shm;
    int shmid = -1;
#endif
#ifdef ENABLE_HAPROXY1
    char remote[BUFSIZE];
    char local[BUFSIZE];
    int dummy;
#endif
#ifdef __OpenBSD__
	char pledges[256];
	char *extra_unveil;
#endif

    /* Get the name of this binary */
    if ((c = strrchr(argv[0], '/'))) sstrlcpy(self, c + 1);
    else sstrlcpy(self, argv[0]);

    /* Initialize state */
#ifdef HAVE_LOCALES
    setlocale(LC_TIME, DATE_LOCALE);
#endif
    init_state(&st);
#ifdef _WIN32
    /* Windows dosen't have getppid() */
    srand(time(NULL) / getpid());
#else
    srand(time(NULL) / (getpid() + getppid()));
#endif

    /* Handle command line arguments */
    parse_args(&st, argc, argv);

    /* Open syslog() */
#ifdef HAVE_SYSLOG
    if (st.opt_syslog) openlog(self, LOG_PID, LOG_DAEMON);
#endif

#ifdef __OpenBSD__
    /* unveil(2) support.
     *
     * We only enable unveil(2) if the user isn't expecting to shell-out to
     * arbitrary commands.
     */
    /*
     * We don't bother with HAVE_SYSLOG checks as OpenBSD has syslog.
     */
    if (st.opt_exec) {
        if (st.extra_unveil_paths != NULL) {
            die(&st, NULL, "-U and executable maps cannot co-exist");
        }
        if (st.debug)
            syslog(LOG_INFO, "executable gophermaps are enabled, no unveil(2)");
    } else {
        if (unveil(st.server_root, "r") == -1)
            die(&st, NULL, "unveil");

        /*
         * If we want personal gopherspaces, then we have to unveil(2) the user
         * database. This isn't actually needed if pledge(2) is enabled, as the
         * 'getpw' promise will ensure access to this file, but it doesn't hurt
         * to unveil it anyway.
         */
        if (st.opt_personal_spaces) {
            if (st.debug)
                syslog(LOG_INFO, "unveiling /etc/pwd.db");
            if (unveil("/etc/pwd.db", "r") == -1)
                die(&st, NULL, "unveil");
        }

        /* Any extra unveil paths that the user has specified */
        char *p = st.extra_unveil_paths;
        while (p != NULL) {
            extra_unveil = strsep(&p, ":");
            if (*extra_unveil == '\0')
                continue; /* empty path */

            if (st.debug)
                syslog(LOG_INFO, "unveiling extra path: %s\n", extra_unveil);
            if (unveil(extra_unveil, "r") == -1)
                die(&st, NULL, "unveil");
        }

        if (unveil(NULL, NULL) == -1)
            die(&st, NULL, "unveil");
    }

    /* pledge(2) support */
    if (st.opt_shm) {
        /* pledge(2) never allows shared memory */
        if (st.debug)
            syslog(LOG_INFO, "shared-memory enabled, can't pledge(2)");
    } else {
        strlcpy(pledges,
                "stdio rpath inet sendfd recvfd proc",
                sizeof(pledges));

        /* Executable maps shell-out using popen(3) */
        if (st.opt_exec) {
            strlcat(pledges, " exec", sizeof(pledges));
            if (st.debug) {
                syslog(LOG_INFO,
                       "executable gophermaps enabled, "
                       "adding 'exec' to pledge(2)");
            }
        }

        /* Personal spaces require getpwnam(3) and getpwent(3) */
        if (st.opt_personal_spaces) {
            strlcat(pledges, " getpw", sizeof(pledges));
            if (st.debug) {
                syslog(LOG_INFO,
                       "personal gopherspaces enabled, "
                       "adding 'getpw' to pledge(2)");
            }
        }

        if (pledge(pledges, NULL) == -1)
            die(&st, NULL, "pledge");
    }
#endif

    /* Check if TCP wrappers have something to say about this connection */
#ifdef HAVE_LIBWRAP
    if (sstrncmp(st.req_remote_addr, UNKNOWN_ADDR) != MATCH &&
        hosts_ctl(self, STRING_UNKNOWN, st.req_remote_addr, STRING_UNKNOWN) == WRAP_DENIED)
        die(&st, ERR_ACCESS, "Refused connection");
#endif

    /* Make sure the computer is turned on */
#ifdef __HAIKU__
    if (is_computer_on() != TRUE)
        die(&st, ERR_ACCESS, "Please turn on the computer first");
#endif

    /* Refuse to run as root */
#ifdef HAVE_PASSWD
    if (st.opt_root && getuid() == 0)
        die(&st, ERR_ACCESS, "Cowardly refusing to run as root");
#endif

    /* Try to get shared memory */
#ifdef HAVE_SHMEM
    if (st.opt_shm) {
        if ((shmid = shmget(SHM_KEY, sizeof(shm_state), IPC_CREAT | SHM_MODE)) == ERROR) {

            /* Getting memory failed -> delete the old allocation */
            shmctl(shmid, IPC_RMID, &shm_ds);
            shm = NULL;
        }
        else {
            /* Map shared memory */
            if ((shm = (shm_state *) shmat(shmid, (void *) 0, 0)) == (void *) ERROR)
                shm = NULL;

            /* Initialize mapped shared memory */
            if (shm && shm->start_time == 0) {
                shm->start_time = time(NULL);

                /* Keep server platform & description in shm */
                platform(&st);
                sstrlcpy(shm->server_platform, st.server_platform);
                sstrlcpy(shm->server_description, st.server_description);
            }
        }
    } else {
        shm = NULL;
    }

    /* Get server platform and description */
    if (shm) {
        sstrlcpy(st.server_platform, shm->server_platform);

        if (!*st.server_description)
            sstrlcpy(st.server_description, shm->server_description);
    }
    else
#endif
        platform(&st);

    /* Read selector */
get_selector:
    if (fgets(selector, sizeof(selector) - 1, stdin) == NULL)
        strclear(selector);

    /* Remove trailing CRLF */
    chomp(selector);

#ifdef HAVE_SYSLOG
    if (st.debug) syslog(LOG_INFO, "client sent us \"%s\"", selector);
#endif

    /* Handle HAproxy/Stunnel proxy protocol v1 */
#ifdef ENABLE_HAPROXY1
    if (sstrncmp(selector, "PROXY TCP") == MATCH && st.opt_proxy) {
#ifdef HAVE_SYSLOG
        if (st.debug) syslog(LOG_INFO, "got proxy protocol header \"%s\"", selector);
#endif

        sscanf(selector, "PROXY TCP%d %s %s %d %d",
            &dummy, remote, local, &dummy, &st.server_port);

        /* Strip ::ffff: IPv4-in-IPv6 prefix and override old addresses */
        sstrlcpy(st.req_local_addr, local + ((sstrncmp(local, "::ffff:") == MATCH) ? 7 : 0));
        sstrlcpy(st.req_remote_addr, remote + ((sstrncmp(remote, "::ffff:") == MATCH) ? 7 : 0));

        /* My precious \o/ */
        goto get_selector;
    }
#endif

    /* Handle hURL: redirect page */
    if (sstrncmp(selector, "URL:") == MATCH) {
        st.req_filetype = TYPE_HTML;
        sstrlcpy(st.req_selector, selector);
        url_redirect(&st);
        return OK;
    }

    /* Handle gopher+ root requests (UMN gopher client is seriously borken) */
    if (sstrncmp(selector, "\t$") == MATCH) {
        printf("+-1" CRLF);
        printf("+INFO: 1Main menu\t\t%s\t%i" CRLF,
            st.server_host,
            st.server_port);
        printf("+VIEWS:" CRLF " application/gopher+-menu: <512b>" CRLF);
        printf("." CRLF);

#ifdef HAVE_SYSLOG
        if (st.debug) syslog(LOG_INFO, "got a request for gopher+ root menu");
#endif
        return OK;
    }

    /* Convert HTTP request to gopher (respond using headerless HTTP/0.9) */
    if (sstrncmp(selector, "GET ") == MATCH ||
        sstrncmp(selector, "POST ") == MATCH ) {

        if ((c = strchr(selector, ' '))) sstrlcpy(selector, c + 1);
        if ((c = strchr(selector, ' '))) *c = '\0';

        st.req_protocol = PROTO_HTTP;
#ifdef HAVE_SYSLOG
        if (st.debug) syslog(LOG_INFO, "got HTTP request for \"%s\"", selector);
#endif
    }

    /* Save default server_host & fetch session data (including new server_host) */
    sstrlcpy(st.server_host_default, st.server_host);
#ifdef HAVE_SHMEM
    if (shm) get_shm_session(&st, shm);
#endif


    /* Parse <tab>search from selector */
    if ((c = strchr(selector, '\t'))) {
        sstrlcpy(st.req_search, c + 1);
        *c = '\0';
    }

    /* Parse ?query from selector */
    if (st.opt_query && (c = strchr(selector, '?'))) {
        sstrlcpy(st.req_query_string, c + 1);
        *c = '\0';
    }

    /* Parse ;vhost from selector */
    if (st.opt_vhost && (c = strchr(selector, ';'))) {
        sstrlcpy(st.server_host, c + 1);
        *c = '\0';
    }

    /* Loop through the selector, fix it & separate query_string */
    dest = st.req_selector;
    if (selector[0] != '/') *dest++ = '/';

    for (c = selector; *c;) {

        /* Skip duplicate slashes and /./ */
        while (*c == '/' && *(c + 1) == '/') c++;
        if (*c == '/' && *(c + 1) == '.' && *(c + 2) == '/') c += 2;

        /* Copy valid char */
        *dest++ = *c++;
    }
    *dest = '\0';

    /* Main query parameters compatibility with older versions of Gophernicus */
    if (*st.req_query_string && !*st.req_search) sstrlcpy(st.req_search, st.req_query_string);
    if (!*st.req_query_string && *st.req_search) sstrlcpy(st.req_query_string, st.req_search);

    /* Remove encodings from selector */
    strndecode(st.req_selector, st.req_selector, sizeof(st.req_selector));

    /* Deny requests for Slashdot and /../ hackers */
    if (strstr(st.req_selector, "/."))
        die(&st, ERR_ACCESS, "Refusing to serve out dotfiles");

    /* Handle /server-status requests */
#ifdef HAVE_SHMEM
    if (st.opt_status && sstrncmp(st.req_selector, SERVER_STATUS) == MATCH) {
        if (shm) server_status(&st, shm, shmid);
        return OK;
    }
#endif

    /* Remove possible extra cruft from server_host */
    if ((c = strchr(st.server_host, '\t'))) *c = '\0';

    /* Guess request filetype so we can die() with style... */
    st.req_filetype = gopher_filetype(&st, st.req_selector, FALSE);

    /* Convert seletor to path & stat() */
    selector_to_path(&st);
#ifdef HAVE_SYSLOG
    if (st.debug) syslog(LOG_INFO, "path to resource is \"%s\"", st.req_realpath);
#endif

    if (stat(st.req_realpath, &file) == ERROR) {

        /* Handle virtual /caps.txt requests */
        if (st.opt_caps && sstrncmp(st.req_selector, CAPS_TXT) == MATCH) {
#ifdef HAVE_SHMEM
            caps_txt(&st, shm);
#else
            caps_txt(&st, NULL);
#endif
            return OK;
        }

        /* Requested file not found - die() */
        die(&st, ERR_NOTFOUND, NULL);
    }

    /* Fetch request filesize from stat() */
    st.req_filesize = file.st_size;

    /* Everyone must have read access but no write access */
    /* Skip this check on Windows */
#ifndef _WIN32
    if ((file.st_mode & S_IROTH) == 0)
        die(&st, ERR_ACCESS, "File or directory not world-readable");
    if ((file.st_mode & S_IWOTH) != 0)
        die(&st, ERR_ACCESS, "File or directory world-writeable");
#endif

    /* If stat said it was a dir then it's a menu */
    if ((file.st_mode & S_IFMT) == S_IFDIR) st.req_filetype = TYPE_MENU;

    /* Not a dir - let's guess the filetype again... */
    else if ((file.st_mode & S_IFMT) == S_IFREG)
        st.req_filetype = gopher_filetype(&st, st.req_realpath, st.opt_magic);

    /* Menu selectors must end with a slash */
    if (st.req_filetype == TYPE_MENU && strlast(st.req_selector) != '/')
        sstrlcat(st.req_selector, "/");

    /* Change directory to wherever the resource was */
    sstrlcpy(buf, st.req_realpath);

    if ((file.st_mode & S_IFMT) != S_IFDIR) c = dirname(buf);
    else c = buf;

    if (chdir(c) == ERROR) die(&st, ERR_ACCESS, NULL);

    /* Keep count of hits and data transfer */
#ifdef HAVE_SHMEM
    if (shm) {
        shm->hits++;
        shm->kbytes += st.req_filesize / 1024;

        /* Update user session */
        update_shm_session(&st, shm);
    }
#endif

    /* Log the request */
#ifdef HAVE_SYSLOG
    if (st.opt_syslog) {
        syslog(LOG_INFO, "request for \"gopher%s://%s:%i/%c%s\" from %s",
            (st.server_port == st.server_tls_port ? "s" : ""),
            st.server_host,
            st.server_port,
            st.req_filetype,
            st.req_selector,
            st.req_remote_addr);
    }
#endif

    /* Check file type & act accordingly */
    switch (file.st_mode & S_IFMT) {
        case S_IFDIR:
            log_combined(&st, HTTP_OK);
            gopher_menu(&st);
            break;

        case S_IFREG:
            log_combined(&st, HTTP_OK);
            gopher_file(&st);
            break;

        default:
            die(&st, ERR_ACCESS, "Refusing to serve out special files");
    }

    /* Clean exit */
    return OK;
}