rcm_daemon/common/rcm_main.c

	rcm_main.c revision 03859504f0d42ac2e32c1828dd62f1a80c4d2ab1
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * Reconfiguration Coordination Daemon
 *
 * Accept RCM messages in the form of RCM events and process them
 * - to build and update the system resource map
 * - to allow clients to register/unregister for resource
 * - to allow dr initiators to offline a resource before removal
 * - to call into clients to perform suspend/offline actions
 *
 * The goal is to enable fully automated Dynamic Reconfiguration and better
 * DR information tracking.
 */

#include <librcm_event.h>

#include "rcm_impl.h"

/* will run in daemon mode if debug level < DEBUG_LEVEL_FORK */
#define DEBUG_LEVEL_FORK    RCM_DEBUG

#define DAEMON_LOCK_FILE "/var/run/rcm_daemon_lock"

static int hold_daemon_lock;
static int daemon_lock_fd;
static const char *daemon_lock_file = DAEMON_LOCK_FILE;

int debug_level = 0;
static int idle_timeout;
static int logflag = 0;
static char *prog;

static void usage(void);
static void catch_sighup(void);
static void catch_sigusr1(void);
static pid_t enter_daemon_lock(void);
static void exit_daemon_lock(void);

extern void init_poll_thread();
extern void cleanup_poll_thread();

/*
 * Print command line syntax for starting rcm_daemon
 */
static void
usage() {
    (void) fprintf(stderr,
        gettext("usage: %s [-d debug_level] [-t idle_timeout]\n"), prog);
    rcmd_exit(EINVAL);
}

/*
 * common cleanup/exit functions to ensure releasing locks
 */
static void
rcmd_cleanup(int status)
{
    if (status == 0) {
        rcm_log_message(RCM_INFO,
            gettext("rcm_daemon normal exit\n"));
    } else {
        rcm_log_message(RCM_ERROR,
            gettext("rcm_daemon exit: errno = %d\n"), status);
    }

    if (hold_daemon_lock) {
        exit_daemon_lock();
    }
}

void
rcmd_exit(int status)
{
    rcmd_cleanup(status);
    exit(status);
}

/*
 * When SIGHUP is received, reload modules at the next safe moment (when
 * there is no DR activity.
 */
void
catch_sighup(void)
{
    rcm_log_message(RCM_INFO,
        gettext("SIGHUP received, will exit when daemon is idle\n"));
    rcmd_thr_signal();
}

/*
 * When SIGUSR1 is received, exit the thread
 */
void
catch_sigusr1(void)
{
    rcm_log_message(RCM_DEBUG, "SIGUSR1 received in thread %d\n",
        thr_self());
    cleanup_poll_thread();
    thr_exit(NULL);
}

/*
 * Use an advisory lock to ensure that only one daemon process is
 * active at any point in time.
 */
static pid_t
enter_daemon_lock(void)
{
    struct flock lock;

    rcm_log_message(RCM_TRACE1,
        "enter_daemon_lock: lock file = %s\n", daemon_lock_file);

    daemon_lock_fd = open(daemon_lock_file, O_CREAT|O_RDWR, 0644);
    if (daemon_lock_fd < 0) {
        rcm_log_message(RCM_ERROR, gettext("open(%s) - %s\n"),
            daemon_lock_file, strerror(errno));
        rcmd_exit(errno);
    }

    lock.l_type = F_WRLCK;
    lock.l_whence = SEEK_SET;
    lock.l_start = 0;
    lock.l_len = 0;

    if (fcntl(daemon_lock_fd, F_SETLK, &lock) == 0) {
        hold_daemon_lock = 1;
        return (getpid());
    }

    /* failed to get lock, attempt to find lock owner */
    if ((errno == EAGAIN || errno == EDEADLK) &&
        (fcntl(daemon_lock_fd, F_GETLK, &lock) == 0)) {
        return (lock.l_pid);
    }

    /* die a horrible death */
    rcm_log_message(RCM_ERROR, gettext("lock(%s) - %s"), daemon_lock_file,
        strerror(errno));
    exit(errno);
    /*NOTREACHED*/
}

/*
 * Drop the advisory daemon lock, close lock file
 */
static void
exit_daemon_lock(void)
{
    struct flock lock;

    lock.l_type = F_UNLCK;
    lock.l_whence = SEEK_SET;
    lock.l_start = 0;
    lock.l_len = 0;

    if (fcntl(daemon_lock_fd, F_SETLK, &lock) == -1) {
        rcm_log_message(RCM_ERROR, gettext("unlock(%s) - %s"),
            daemon_lock_file, strerror(errno));
    }

    (void) close(daemon_lock_fd);
}

/*PRINTFLIKE2*/
static void
rcm_log_msg_impl(int level, char *message, va_list ap)
{
    int log_level;

    if (!logflag) {
        /*
         * RCM_ERROR goes to stderr, others go to stdout
         */
        FILE *out = (level <= RCM_ERROR) ? stderr : stdout;
        (void) vfprintf(out, message, ap);
        return;
    }

    /*
     * translate RCM_* to LOG_*
     */
    switch (level) {
    case RCM_ERROR:
        log_level = LOG_ERR;
        break;

    case RCM_WARNING:
        log_level = LOG_WARNING;
        break;

    case RCM_NOTICE:
        log_level = LOG_NOTICE;
        break;

    case RCM_INFO:
        log_level = LOG_INFO;
        break;

    case RCM_DEBUG:
        log_level = LOG_DEBUG;
        break;

    default:
        /*
         * Don't log RCM_TRACEn messages
         */
        return;
    }

    (void) vsyslog(log_level, message, ap);
}

/*
 * print error messages to the terminal or to syslog
 */
void
rcm_log_message(int level, char *message, ...)
{
    va_list ap;

    if (level > debug_level) {
        return;
    }

    va_start(ap, message);
    rcm_log_msg_impl(level, message, ap);
    va_end(ap);
}

/*
 * Print error messages to the terminal or to syslog.
 * Same as rcm_log_message except that it does not check for
 * level > debug_level
 * allowing callers to override the global debug_level.
 */
void
rcm_log_msg(int level, char *message, ...)
{
    va_list ap;

    va_start(ap, message);
    rcm_log_msg_impl(level, message, ap);
    va_end(ap);
}

/*
 * grab daemon_lock and direct messages to syslog
 */
static void
detachfromtty()
{
    (void) chdir("/");
    (void) setsid();
    (void) close(0);
    (void) close(1);
    (void) close(2);
    (void) open("/dev/null", O_RDWR, 0);
    (void) dup2(0, 1);
    (void) dup2(0, 2);
    openlog(prog, LOG_PID, LOG_DAEMON);
    logflag = 1;
}

int
main(int argc, char **argv)
{
    int c;
    pid_t pid;
    extern char *optarg;
    sigset_t mask;
    struct sigaction act;

    (void) setlocale(LC_ALL, "");
#ifndef TEXT_DOMAIN
#define TEXT_DOMAIN "SYS_TEST"
#endif
    (void) textdomain(TEXT_DOMAIN);

    if ((prog = strrchr(argv[0], '/')) == NULL) {
        prog = argv[0];
    } else {
        prog++;
    }

    /*
     * process arguments
     */
    if (argc > 3) {
        usage();
    }
    while ((c = getopt(argc, argv, "d:t:")) != EOF) {
        switch (c) {
        case 'd':
            debug_level = atoi(optarg);
            break;
        case 't':
            idle_timeout = atoi(optarg);
            break;
        case '?':
        default:
            usage();
            /*NOTREACHED*/
        }
    }

    /*
     * Check permission
     */
    if (getuid() != 0) {
        (void) fprintf(stderr, gettext("Must be root to run %s\n"),
            prog);
        exit(EPERM);
    }

    /*
     * When rcm_daemon is started by a call to librcm, it inherits file
     * descriptors from the DR initiator making a call. The file
     * descriptors may correspond to devices that can be removed by DR.
     * Since keeping them remain opened is problematic, close everything
     * but stdin/stdout/stderr.
     */
    closefrom(3);

    /*
     * block SIGUSR1, use it for killing specific threads
     */
    (void) sigemptyset(&mask);
    (void) sigaddset(&mask, SIGUSR1);
    (void) thr_sigsetmask(SIG_BLOCK, &mask, NULL);

    /*
     * Setup signal handlers for SIGHUP and SIGUSR1
     * SIGHUP - causes a "delayed" daemon exit, effectively the same
     *  as a daemon restart.
     * SIGUSR1 - causes a thr_exit(). Unblocked in selected threads.
     */
    act.sa_flags = 0;
    act.sa_handler = catch_sighup;
    (void) sigaction(SIGHUP, &act, NULL);
    act.sa_handler = catch_sigusr1;
    (void) sigaction(SIGUSR1, &act, NULL);

    /*
     * ignore SIGPIPE so that the rcm daemon does not exit when it
     * attempts to read or write from a pipe whose corresponding
     * rcm script process exited.
     */
    act.sa_handler = SIG_IGN;
    (void) sigaction(SIGPIPE, &act, NULL);

    /*
     * run in daemon mode
     */
    if (debug_level < DEBUG_LEVEL_FORK) {
        if (fork()) {
            exit(0);
        }
        detachfromtty();
    }

    /* only one daemon can run at a time */
    if ((pid = enter_daemon_lock()) != getpid()) {
        rcm_log_message(RCM_DEBUG, "%s pid %d already running\n",
            prog, pid);
        exit(EDEADLK);
    }

    rcm_log_message(RCM_TRACE1, "%s started, debug level = %d\n",
        prog, debug_level);

    /*
     * Set daemon state to block RCM requests before rcm_daemon is
     * fully initialized. See rcmd_thr_incr().
     */
    rcmd_set_state(RCMD_INIT);

    /*
     * create rcm_daemon door and set permission to 0400
     */
    if (create_event_service(RCM_SERVICE_DOOR, event_service) == -1) {
        rcm_log_message(RCM_ERROR,
            gettext("cannot create door service: %s\n"),
            strerror(errno));
        rcmd_exit(errno);
    }
    (void) chmod(RCM_SERVICE_DOOR, S_IRUSR);

    init_poll_thread(); /* initialize poll thread related data */

    /*
     * Initialize database by asking modules to register.
     */
    rcmd_db_init();

    /*
     * Initialize locking, including lock recovery in the event of
     * unexpected daemon failure.
     */
    rcmd_lock_init();

    /*
     * Start accepting normal requests
     */
    rcmd_set_state(RCMD_NORMAL);

    /*
     * Start cleanup thread
     */
    rcmd_db_clean();

    /*
     * Loop within daemon and return after a period of inactivity.
     */
    rcmd_start_timer(idle_timeout);

    rcmd_cleanup(0);
    return (0);
}