source: unix.c @ af09afd

/********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2012 Wilmer van der Gaast and others                *
  \********************************************************************/

/* Main file (Unix specific part)                                       */

/*
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 51 Franklin St.,
  Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "bitlbee.h"

#include "arc.h"
#include "base64.h"
#include "commands.h"
#include "protocols/nogaim.h"
#include "help.h"
#include "ipc.h"
#include "md5.h"
#include "misc.h"
#include <signal.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <pwd.h>
#include <locale.h>
#include <grp.h>

#if defined(OTR_BI) || defined(OTR_PI)
#include "otr.h"
#endif

#ifdef HAVE_BACKTRACE
#include <execinfo.h>
#endif

global_t global;        /* Against global namespace pollution */

static struct {
        int fd[2];
        int tag;
} shutdown_pipe = {{-1 , -1}, 0};

static void sighandler_shutdown(int signal);
static void sighandler_crash(int signal);

static int crypt_main(int argc, char *argv[]);

int main(int argc, char *argv[])
{
        int i = 0;
        char *old_cwd = NULL;
        struct sigaction sig, old;
#ifdef HAVE_BACKTRACE
        void *unused[1];
#endif

        /* Required to make iconv to ASCII//TRANSLIT work. This makes BitlBee
           system-locale-sensitive. :-( */
        setlocale(LC_CTYPE, "");

        if (argc > 1 && strcmp(argv[1], "-x") == 0) {
                return crypt_main(argc, argv);
        }

        log_init();
        /* Catch early errors */
        log_link(LOGLVL_ERROR, LOGOUTPUT_CONSOLE);
        log_link(LOGLVL_WARNING, LOGOUTPUT_CONSOLE);

        global.conf_file = g_strdup(CONF_FILE_DEF);
        global.conf = conf_load(argc, argv);
        if (global.conf == NULL) {
                return(1);
        }

        if (global.conf->runmode == RUNMODE_INETD) {
                log_link(LOGLVL_ERROR, LOGOUTPUT_IRC);
                log_link(LOGLVL_WARNING, LOGOUTPUT_IRC);
        } else {
                log_link(LOGLVL_ERROR, LOGOUTPUT_CONSOLE);
                log_link(LOGLVL_WARNING, LOGOUTPUT_CONSOLE);
        }

        b_main_init();

        /* libpurple doesn't like fork()s after initializing itself, so if
           we use it, do this init a little later (in case we're running in
           ForkDaemon mode). */
#ifndef WITH_PURPLE
        nogaim_init();
#endif

#ifdef OTR_BI
        otr_init();
#endif

        global.helpfile = g_strdup(HELP_FILE);
        if (help_init(&global.help, global.helpfile) == NULL) {
                log_message(LOGLVL_WARNING, "Error opening helpfile %s.", HELP_FILE);
        }

        global.storage = storage_init(global.conf->primary_storage, global.conf->migrate_storage);
        if (global.storage == NULL) {
                log_message(LOGLVL_ERROR, "Unable to load storage backend '%s'", global.conf->primary_storage);
                return(1);
        }

        global.auth = auth_init(global.conf->auth_backend);
        if (global.conf->auth_backend && global.auth == NULL) {
                log_message(LOGLVL_ERROR, "Unable to load authentication backend '%s'", global.conf->auth_backend);
                return(1);
        }

        if (global.conf->runmode == RUNMODE_INETD) {
                i = bitlbee_inetd_init();
                log_message(LOGLVL_INFO, "%s %s starting in inetd mode.", PACKAGE, BITLBEE_VERSION);

        } else if (global.conf->runmode == RUNMODE_DAEMON) {
                i = bitlbee_daemon_init();
                log_message(LOGLVL_INFO, "%s %s starting in daemon mode.", PACKAGE, BITLBEE_VERSION);
        } else if (global.conf->runmode == RUNMODE_FORKDAEMON) {
                /* In case the operator requests a restart, we need this. */
                old_cwd = g_malloc(256);
                if (getcwd(old_cwd, 255) == NULL) {
                        log_message(LOGLVL_WARNING, "Could not save current directory: %s", strerror(errno));
                        g_free(old_cwd);
                        old_cwd = NULL;
                }

                i = bitlbee_daemon_init();
                log_message(LOGLVL_INFO, "%s %s starting in forking daemon mode.", PACKAGE, BITLBEE_VERSION);
        }
        if (i != 0) {
                return(i);
        }

        if ((global.conf->user && *global.conf->user) &&
            (global.conf->runmode == RUNMODE_DAEMON ||
             global.conf->runmode == RUNMODE_FORKDAEMON) &&
            (!getuid() || !geteuid())) {
                struct passwd *pw = NULL;
                pw = getpwnam(global.conf->user);
                if (!pw) {
                        log_message(LOGLVL_ERROR, "Failed to look up user %s.", global.conf->user);
                        return(EXIT_FAILURE);

                } else if (initgroups(global.conf->user, pw->pw_gid) != 0) {
                        log_message(LOGLVL_ERROR, "initgroups: %s.", strerror(errno));
                        return(EXIT_FAILURE);

                } else if (setgid(pw->pw_gid) != 0) {
                        log_message(LOGLVL_ERROR, "setgid(%d): %s.", pw->pw_gid, strerror(errno));
                        return(EXIT_FAILURE);

                } else if (setuid(pw->pw_uid) != 0) {
                        log_message(LOGLVL_ERROR, "setuid(%d): %s.", pw->pw_uid, strerror(errno));
                        return(EXIT_FAILURE);
                }
        }

        /* Catch some signals to tell the user what's happening before quitting */
        memset(&sig, 0, sizeof(sig));
        sig.sa_handler = SIG_IGN;
        sigaction(SIGCHLD, &sig, &old);
        sigaction(SIGPIPE, &sig, &old);
        sig.sa_flags = SA_RESETHAND;
        sig.sa_handler = sighandler_crash;
        sigaction(SIGSEGV, &sig, &old);

        sighandler_shutdown_setup();

        sig.sa_handler = sighandler_shutdown;
        sigaction(SIGINT, &sig, &old);
        sigaction(SIGTERM, &sig, &old);

#ifdef HAVE_BACKTRACE
        /* As per the backtrace(3) man page, call this outside of the signal
         * handler once to ensure any dynamic libraries are loaded in an
         * async-signal-safe environment to prevent deadlocks */
        backtrace(unused, 1);
#endif

        if (!getuid() || !geteuid()) {
                log_message(LOGLVL_WARNING, "BitlBee is running with root privileges. Why?");
        }

        b_main_run();

        /* Mainly good for restarting, to make sure we close the help.txt fd. */
        help_free(&global.help);

        if (global.restart) {
                char *fn = ipc_master_save_state();
                char *env;

                env = g_strdup_printf("_BITLBEE_RESTART_STATE=%s", fn);
                putenv(env);
                g_free(fn);
                /* Looks like env should *not* be freed here as putenv
                   doesn't make a copy. Odd. */

                i = chdir(old_cwd);
                close(global.listen_socket);

                if (execv(argv[0], argv) == -1) {
                        /* Apparently the execve() failed, so let's just
                           jump back into our own/current main(). */
                        /* Need more cleanup code to make this work. */
                        return 1; /* main( argc, argv ); */
                }
        }

        return(0);
}

static int crypt_main(int argc, char *argv[])
{
        int pass_len;
        unsigned char *pass_cr, *pass_cl;

        if (argc < 4 || (strcmp(argv[2], "hash") != 0 &&
                         strcmp(argv[2], "unhash") != 0 && argc < 5)) {
                printf("Supported:\n"
                       "  %s -x enc <key> <cleartext password>\n"
                       "  %s -x dec <key> <encrypted password>\n"
                       "  %s -x hash <cleartext password>\n"
                       "  %s -x unhash <hashed password>\n"
                       "  %s -x chkhash <hashed password> <cleartext password>\n",
                       argv[0], argv[0], argv[0], argv[0], argv[0]);
        } else if (strcmp(argv[2], "enc") == 0) {
                char *encoded;

                pass_len = arc_encode(argv[4], strlen(argv[4]), &pass_cr, argv[3], 12);

                encoded = base64_encode(pass_cr, pass_len);
                printf("%s\n", encoded);
                g_free(encoded);
                g_free(pass_cr);
        } else if (strcmp(argv[2], "dec") == 0) {
                pass_len = base64_decode(argv[4], &pass_cr);
                arc_decode(pass_cr, pass_len, (char **) &pass_cl, argv[3]);
                printf("%s\n", pass_cl);

                g_free(pass_cr);
                g_free(pass_cl);
        } else if (strcmp(argv[2], "hash") == 0) {
                guint8 pass_md5[21];
                GChecksum *md5_state;
                gsize digest_len = MD5_HASH_SIZE;
                char *encoded;

                random_bytes(pass_md5 + 16, 5);
                md5_state = g_checksum_new(G_CHECKSUM_MD5);
                g_checksum_update(md5_state, (guint8 *) argv[3], strlen(argv[3]));
                g_checksum_update(md5_state, pass_md5 + 16, 5);   /* Add the salt. */
                g_checksum_get_digest(md5_state, pass_md5, &digest_len);
                g_checksum_free(md5_state);

                encoded = base64_encode(pass_md5, 21);
                printf("%s\n", encoded);
                g_free(encoded);
        } else if (strcmp(argv[2], "unhash") == 0) {
                printf("Hash %s submitted to a massive Beowulf cluster of\n"
                       "overclocked 486s. Expect your answer next year somewhere around this time. :-)\n", argv[3]);
        } else if (strcmp(argv[2], "chkhash") == 0) {
                char *hash = strncmp(argv[3], "md5:", 4) == 0 ? argv[3] + 4 : argv[3];
                int st = md5_verify_password(argv[4], hash);

                printf("Hash %s given password.\n", st == 0 ? "matches" : "does not match");

                return st;
        }

        return 0;
}

/* Set up a pipe for SIGTERM/SIGINT so the actual signal handler doesn't do anything unsafe */
void sighandler_shutdown_setup()
{
        if (shutdown_pipe.fd[0] != -1) {
                /* called again from a forked process, clean up to avoid propagating the signal */
                b_event_remove(shutdown_pipe.tag);
                close(shutdown_pipe.fd[0]);
                close(shutdown_pipe.fd[1]);
        }

        if (pipe(shutdown_pipe.fd) == 0) {
                shutdown_pipe.tag = b_input_add(shutdown_pipe.fd[0], B_EV_IO_READ, bitlbee_shutdown, NULL);
        }
}

/* Signal handler for SIGTERM and SIGINT */
static void sighandler_shutdown(int signal)
{
        int unused G_GNUC_UNUSED;
        /* Write a single null byte to the pipe, just to send a message to the main loop.
         * This gets handled by bitlbee_shutdown (the b_input_add callback for this pipe) */
        unused = write(shutdown_pipe.fd[1], "", 1);
}

#ifdef HAVE_BACKTRACE
/* Writes a backtrace to (usually) /var/lib/bitlbee/crash.log
 * No malloc allowed means not a lot can be written to that file */
static void sighandler_crash_backtrace()
{
        int fd, mapsfd;
        int size;
        void *trace[128];
        const char message[] = "## " PACKAGE " crashed\n"
                "## Version: " BITLBEE_VERSION "\n"
                "## Configure args: " BITLBEE_CONFIGURE_ARGS "\n"
                "##\n"
                "## Backtrace:\n\n";
        const char message2[] = "\n"
                "## Hint: To get details on addresses use\n"
                "##   addr2line -e <binary> <address>\n"
                "## or\n"
                "##   gdb <binary> -ex 'l *<address>' -ex q\n"
                "## where <binary> is a filename from above and <address> is the part between (...)\n"
                "##\n\n";
        const char message3[] = "\n## End of memory maps. See above for the backtrace\n\n";

        fd = open(CRASHFILE, O_WRONLY | O_APPEND | O_CREAT, 0600);

        if (fd == -1 || write(fd, message, sizeof(message) - 1) == -1) {
                return;
        }

        size = backtrace(trace, 128);
        backtrace_symbols_fd(trace, size, fd);

        (void) write(fd, message2, sizeof(message2) - 1);

        /* a bit too linux-specific, so fail gracefully */
        mapsfd = open("/proc/self/maps", O_RDONLY, 0);

        if (mapsfd != -1) {
                char buf[4096] = {0};
                ssize_t bytes;

                while ((bytes = read(mapsfd, buf, sizeof(buf))) > 0) {
                        (void) write(fd, buf, bytes);
                }
                (void) close(mapsfd);
                (void) write(fd, message3, sizeof(message3) - 1);
        }

        (void) close(fd);
}
#endif

/* Signal handler for SIGSEGV
 * A desperate attempt to tell the user that everything is wrong in the world.
 * Avoids using irc_abort() because it has several unsafe calls to malloc */
static void sighandler_crash(int signal)
{
        GSList *l;
        const char message[] = "ERROR :BitlBee crashed! (SIGSEGV received)\r\n"
#ifdef HAVE_BACKTRACE
                "ERROR :Writing backtrace to " CRASHFILE "\r\n"
#endif
                "ERROR :This is a bug either in BitlBee or a plugin, ask us on IRC if unsure\r\n";

        for (l = irc_connection_list; l; l = l->next) {
                irc_t *irc = l->data;
                sock_make_blocking(irc->fd);
                if (irc->sendbuffer) {
                        (void) write(irc->fd, irc->sendbuffer->str, irc->sendbuffer->len);
                }
                (void) write(irc->fd, message, sizeof(message) - 1);
        }

#ifdef HAVE_BACKTRACE
        sighandler_crash_backtrace();
#endif

        raise(signal);
}

double gettime()
{
        struct timeval time[1];

        gettimeofday(time, 0);
        return((double) time->tv_sec + (double) time->tv_usec / 1000000);
}