lib/nwamd/main.c

	main.c revision 9b38c94425adf01f8223f4710a89ca01d6be3386
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

/*
 * nwamd - NetWork Auto-Magic Daemon
 */

#include <fcntl.h>
#include <priv.h>
#include <pthread.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <syslog.h>
#include <unistd.h>
#include <locale.h>
#include <libintl.h>
#include <errno.h>

#include "defines.h"
#include "structures.h"
#include "functions.h"
#include "variables.h"

#define TIMESPECGT(x, y)    ((x.tv_sec > y.tv_sec) || \
        ((x.tv_sec == y.tv_sec) && (x.tv_nsec > y.tv_nsec)))

const char *OUR_FMRI = "svc:/network/physical:nwam";
const char *OUR_PG = "nwamd";

boolean_t fg = B_FALSE;
boolean_t shutting_down;
sigset_t original_sigmask;
char zonename[ZONENAME_MAX];

/*
 * nwamd
 *
 * This is the Network Auto-Magic daemon.  For further high level information
 * see the Network Auto-Magic project and the Approachability communities
 * on opensolaris.org, and nwamd(1M).
 *
 * The general structure of the code is as a set of threads collecting
 * system events which are fed into a state machine which alters system
 * state based on configuration.
 *
 * signal management
 * Due to being threaded, a simple set of signal handlers would not work
 * very well for nwamd.  Instead nwamd blocks signals at startup and
 * then starts a thread which sits in sigwait(2) waiting for signals.
 * When a signal is received the signal handling thread dispatches it.
 * It handles:
 * - shutting down, done by creating an event which is passed through the
 *   system allowing the various subsystems to do any necessary cleanup.
 * - SIGALRM for timers.
 * - SIGHUP for instance refresh, which tells us to look up various
 *   properties from SMF(5).
 *
 * subprocess management
 * nwamd starts several different subprocesses to manage the system.  Some
 * of those start other processes (e.g. `ifconfig <if> dhcp` ends up starting
 * dhcpagent if necessary).  Due to the way we manage signals if we started
 * those up without doing anything special their signal mask would mostly
 * block signals.  So we restore the signal mask when we start subprocesses.
 * This is especially important with respect to DHCP as later when we exit
 * we need to kill the dhcpagent process which we started; for details, see
 * the block comment in state_machine.c in its cleanup() function.
 */

/*
 * In this file there are several utility functions which might otherwise
 * belong in util.c, but since they are only called from main(), they can
 * live here as static functions:
 * - syslog set-up
 * - daemonizing
 * - looking up SMF(5) properties
 * - signal handling
 * - managing privileges(5)
 */

static void
start_logging(void)
{
    openlog("nwamd", LOG_PID | LOG_NDELAY, LOG_DAEMON);
}

static void
daemonize(void)
{
    pid_t pid;

    /*
     * A little bit of magic here.  By the first fork+setsid, we
     * disconnect from our current controlling terminal and become
     * a session group leader.  By forking again without calling
     * setsid again, we make certain that we are not the session
     * group leader and can never reacquire a controlling terminal.
     */
    if ((pid = fork()) == (pid_t)-1) {
        syslog(LOG_ERR, "fork 1 failed");
        exit(EXIT_FAILURE);
    }
    if (pid != 0) {
        (void) wait(NULL);
        dprintf("child %ld exited, daemonizing", pid);
        _exit(0);
    }
    if (setsid() == (pid_t)-1) {
        syslog(LOG_ERR, "setsid");
        exit(EXIT_FAILURE);
    }
    if ((pid = fork()) == (pid_t)-1) {
        syslog(LOG_ERR, "fork 2 failed");
        exit(EXIT_FAILURE);
    }
    if (pid != 0) {
        _exit(0);
    }
    (void) chdir("/");
    (void) umask(022);
}

/*
 * Look up nwamd property values and set daemon variables appropriately.
 * This function will be called on startup and via the signal handling
 * thread on receiving a HUP (which occurs when the nwam service is
 * refreshed).
 */
static void
lookup_daemon_properties(void)
{
    boolean_t debug_set;
    uint64_t scan_interval;

    if (lookup_boolean_property(OUR_PG, "debug", &debug_set) == 0)
        debug = debug_set;
    if (lookup_count_property(OUR_PG, "scan_interval", &scan_interval) == 0)
        wlan_scan_interval = scan_interval;
    dprintf("Read daemon configuration properties.");
}

/* ARGSUSED */
static void *
sighandler(void *arg)
{
    struct np_event *ev;
    sigset_t sigset;
    int sig;
    uint32_t now;

    (void) sigfillset(&sigset);

    for (;;) {
        sig = sigwait(&sigset);
        dprintf("signal %d caught", sig);
        switch (sig) {
        case SIGALRM:
            /*
             * We may have multiple interfaces with
             * scheduled timers; walk the list and
             * create a timer event for each one.
             */
            timer_expire = TIMER_INFINITY;
            now = NSEC_TO_SEC(gethrtime());
            walk_interface(check_interface_timer, &now);
            break;
        case SIGHUP:
            /*
             * Refresh action - reread configuration properties.
             */
            lookup_daemon_properties();
            break;
        default:
            syslog(LOG_NOTICE, "%s received, shutting down",
                strsignal(sig));
            shutting_down = B_TRUE;
            if ((ev = malloc(sizeof (*ev))) == NULL) {
                dprintf("could not allocate shutdown event");
                cleanup();
                exit(EXIT_FAILURE);
            }
            ev->npe_type = EV_SHUTDOWN;
            ev->npe_name = NULL;
            np_queue_add_event(ev);
            break;
        }

        /* if we're shutting down, exit this thread */
        if (shutting_down)
            return (NULL);
    }
}

static void
init_signalhandling(void)
{
    pthread_attr_t attr;
    pthread_t sighand;
    int err;
    sigset_t new;

    (void) sigfillset(&new);
    (void) pthread_sigmask(SIG_BLOCK, &new, &original_sigmask);
    (void) pthread_attr_init(&attr);
    (void) pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
    if (err = pthread_create(&sighand, &attr, sighandler, NULL)) {
        syslog(LOG_ERR, "pthread_create system: %s", strerror(err));
        exit(EXIT_FAILURE);
    } else {
        dprintf("signal handler thread: %d", sighand);
    }
    (void) pthread_attr_destroy(&attr);
}

static void
change_user_set_privs(void)
{
    priv_set_t *priv_set;

    priv_set = priv_allocset();
    if (getppriv(PRIV_PERMITTED, priv_set) == -1) {
        dprintf("getppriv %s", strerror(errno));
    } else {
        char *p;

        p = priv_set_to_str(priv_set, ',', 0);
        dprintf("started with privs %s", p != NULL ? p : "Unknown");
        free(p);
    }
    priv_freeset(priv_set);

    /* always start with the basic set */
    priv_set = priv_str_to_set("basic", ",", NULL);
    if (priv_set == NULL) {
        syslog(LOG_ERR, "converting basic privilege set: %m");
        exit(EXIT_FAILURE);
    }
    (void) priv_addset(priv_set, PRIV_FILE_CHOWN_SELF);
    (void) priv_addset(priv_set, PRIV_FILE_DAC_READ);
    (void) priv_addset(priv_set, PRIV_FILE_DAC_WRITE);
    (void) priv_addset(priv_set, PRIV_NET_PRIVADDR);
    (void) priv_addset(priv_set, PRIV_NET_RAWACCESS);
    (void) priv_addset(priv_set, PRIV_PROC_OWNER);
    (void) priv_addset(priv_set, PRIV_PROC_SETID);
    (void) priv_addset(priv_set, PRIV_SYS_IP_CONFIG);
    (void) priv_addset(priv_set, PRIV_SYS_IPC_CONFIG);
    (void) priv_addset(priv_set, PRIV_SYS_NET_CONFIG);
    (void) priv_addset(priv_set, PRIV_SYS_RES_CONFIG);
    (void) priv_addset(priv_set, PRIV_SYS_RESOURCE);

    if (setppriv(PRIV_SET, PRIV_INHERITABLE, priv_set) == -1) {
        syslog(LOG_ERR, "setppriv inheritable: %m");
        priv_freeset(priv_set);
        exit(EXIT_FAILURE);
    }

    if (setppriv(PRIV_SET, PRIV_PERMITTED, priv_set) == -1) {
        syslog(LOG_ERR, "setppriv permitted: %m");
        priv_freeset(priv_set);
        exit(EXIT_FAILURE);
    }

    if (setppriv(PRIV_SET, PRIV_EFFECTIVE, priv_set) == -1) {
        syslog(LOG_ERR, "setppriv effective: %m");
        priv_freeset(priv_set);
        exit(EXIT_FAILURE);
    }

    priv_freeset(priv_set);
}

int
main(int argc, char *argv[])
{
    int c;
    int scan_lev;
    struct np_event *e;

    (void) setlocale(LC_ALL, "");
    (void) textdomain(TEXT_DOMAIN);

    shutting_down = B_FALSE;
    start_logging();
    syslog(LOG_INFO, "nwamd pid %d started", getpid());

    while ((c = getopt(argc, argv, "fs:")) != -1) {
        switch (c) {
            case 'f':
                fg = B_TRUE;
                break;
            case 's':
                scan_lev = atoi(optarg);
                if (scan_lev >= DLADM_WLAN_STRENGTH_VERY_WEAK &&
                    scan_lev <= DLADM_WLAN_STRENGTH_EXCELLENT) {
                    wireless_scan_level = scan_lev;
                } else {
                    syslog(LOG_ERR, "invalid signal "
                        "strength: %s", optarg);
                }
                break;
            default:
                syslog(LOG_ERR, "unrecognized option %c",
                    optopt);
                break;
        }
    }

    lookup_daemon_properties();

    change_user_set_privs();

    if (!fg)
        daemonize();

    init_signalhandling();

    init_mutexes();

    lookup_zonename(zonename, sizeof (zonename));

    initialize_interfaces();

    llp_parse_config();

    (void) start_event_collection();

    while ((e = np_queue_get_event()) != NULL) { /* forever */

        syslog(LOG_INFO, "got event type %s",
            npe_type_str(e->npe_type));
        switch (e->npe_type) {
            case EV_ROUTING:
            case EV_NEWADDR:
            case EV_TIMER:
                state_machine(e);
                free_event(e);
                break;
            case EV_SYS:
                free_event(e);
                break;
            case EV_SHUTDOWN:
                state_machine(e);
                (void) pthread_cancel(routing);
                (void) pthread_cancel(scan);
                (void) pthread_join(routing, NULL);
                (void) pthread_join(scan, NULL);
                syslog(LOG_INFO, "nwamd shutting down");
                exit(EXIT_SUCCESS);
                /* NOTREACHED */
            default:
                free_event(e);
                syslog(LOG_NOTICE, "unknown event");
                break;
        }
    }
    return (0);
}