cmd/ttymon/ttymon.c

/*
 * 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 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */

#include <stdio_ext.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <poll.h>
#include <string.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/stropts.h>
#include <sys/resource.h>
#include <sys/termios.h>
#include <pwd.h>
#include <grp.h>
#include <unistd.h>
#include <ulimit.h>

#include "sac.h"
#include "ttymon.h"
#include "tmstruct.h"
#include "tmextern.h"

static  int Initialized;

extern  int Retry;
extern  struct  pollfd  *Pollp;
static  void    initialize();
static  void    open_all();
static  int set_poll();
static  int check_spawnlimit();
static  int mod_ttydefs();

void    open_device();
void    set_softcar();

extern  int check_session();
extern  void    sigalarm();
extern  void    revokedevaccess(char *, uid_t, gid_t, mode_t);
/* can't include libdevinfo.h */
extern int di_devperm_logout(const char *);

/*
 *  ttymon  - a port monitor under SAC
 *      - monitor ports, set terminal modes, baud rate
 *        and line discipline for the port
 *      - invoke service on port if connection request received
 *      - Usage: ttymon
 *           ttymon -g [options]
 *           Valid options are
 *           -h
 *           -d device
 *           -l ttylabel
 *           -t timeout
 *           -m modules
 *           -p prompt
 *
 *      - ttymon without args is invoked by SAC
 *      - ttymon -g is invoked by process that needs to
 *        have login service on the fly
 */

int
main(int argc, char *argv[])
{
    int nfds;
    extern  char    *lastname();

    /*
     * Only the superuser should execute this command.
     */
    if (getuid() != 0)
        return (1);

    /* remember original signal mask and dispositions */
    (void) sigprocmask(SIG_SETMASK, NULL, &Origmask);
    (void) sigaction(SIGINT, NULL, &Sigint);
    (void) sigaction(SIGALRM, NULL, &Sigalrm);
    (void) sigaction(SIGPOLL, NULL, &Sigpoll);
    (void) sigaction(SIGQUIT, NULL, &Sigquit);
    (void) sigaction(SIGCLD, NULL, &Sigcld);
    (void) sigaction(SIGTERM, NULL, &Sigterm);
#ifdef  DEBUG
    (void) sigaction(SIGUSR1, NULL, &Sigusr1);
    (void) sigaction(SIGUSR2, NULL, &Sigusr2);
#endif

    /*
     * SIGQUIT needs to be ignored. Otherwise, hitting ^\ from
     * console kills ttymon.
     */
    (void) signal(SIGQUIT, SIG_IGN);

    if ((argc > 1) || (strcmp(lastname(argv[0]), "getty") == 0)) {
        ttymon_express(argc, argv);
        return (1); /*NOTREACHED*/
    }

    initialize();

    for (;;) {
        nfds = set_poll(Pollp);
        if (!Reread_flag) {
            if (nfds > 0)
                do_poll(Pollp, nfds);
            else
                (void) pause();
        }
        /*
         * READDB messages may arrive during poll or pause.
         * So the flag needs to be checked again.
         */
        if (Reread_flag) {
            Reread_flag = FALSE;
            re_read();
        }
        while (Retry) {
            Retry = FALSE;
            open_all();
        }
    }
}

static  void
initialize()
{
    struct  pmtab   *tp;
    register struct passwd *pwdp;
    register struct group   *gp;
    struct  rlimit rlimit;
    extern  struct  rlimit  Rlimit;
    extern   uid_t  Uucp_uid;
    extern   gid_t  Tty_gid;

#ifdef  DEBUG
    extern  opendebug();
#endif
    Initialized = FALSE;
    /*
     * get_environ() must be called first,
     * otherwise we don't know where the log file is
     */
    get_environ();
    openttymonlog();
    openpid();
    openpipes();
    setup_PCpipe();

    log("PMTAG: %s", Tag);
    log("Starting state: %s",
        (State == PM_ENABLED) ? "enabled" : "disabled");

#ifdef  DEBUG
    opendebug(FALSE);
    debug("***** ttymon in initialize *****");
    log("debug mode is \t on");
#endif

    catch_signals();

    /* register to receive SIGPOLL when data comes to pmpipe */
    if (ioctl(Pfd, I_SETSIG, S_INPUT) < 0)
        fatal("I_SETSIG on pmpipe failed: %s", strerror(errno));

    sacpoll(); /* this is needed because there may be data already */

    Maxfiles = (int)ulimit(4, 0L);  /* get max number of open files */
    if (Maxfiles < 0)
        fatal("ulimit(4,0L) failed: %s", strerror(errno));

    if (getrlimit(RLIMIT_NOFILE, &Rlimit) == -1)
        fatal("getrlimit failed: %s", strerror(errno));

    rlimit.rlim_cur = rlimit.rlim_max = Rlimit.rlim_max;
    if (setrlimit(RLIMIT_NOFILE, &rlimit) == -1)
        fatal("setrlimit failed: %s", strerror(errno));

    (void) enable_extended_FILE_stdio(-1, -1);

    Maxfiles = rlimit.rlim_cur;
    Maxfds = Maxfiles - FILE_RESERVED;

    log("max open files = %d", Maxfiles);
    log("max ports ttymon can monitor = %d", Maxfds);

    read_pmtab();

    /*
     * setup poll array
     *  - we allocate 10 extra pollfd so that
     *    we do not have to re-malloc when there is
     *    minor fluctuation in Nentries
     */
    Npollfd = Nentries + 10;
    if (Npollfd > Maxfds)
        Npollfd = Maxfds;
    if ((Pollp = (struct pollfd *)
        malloc((unsigned)(Npollfd * sizeof (struct pollfd))))
        == (struct pollfd *)NULL)
        fatal("malloc for Pollp failed");

    (void) mod_ttydefs();   /* just to initialize Mtime */
    if (check_version(TTYDEFS_VERS, TTYDEFS) != 0)
        fatal("check /etc/ttydefs version failed");

    read_ttydefs(NULL, FALSE);

    /* initialize global variables, Uucp_uid & Tty_gid */
    if ((pwdp = getpwnam(UUCP)) != NULL)
        Uucp_uid = pwdp->pw_uid;
    if ((gp = getgrnam(TTY)) == NULL)
        log("no group entry for <tty>, default is used");
    else
        Tty_gid = gp->gr_gid;
    endgrent();
    endpwent();
#ifdef  DEBUG
    debug("Uucp_uid = %u, Tty_gid = %u", Uucp_uid, Tty_gid);
#endif

    log("Initialization Completed");

    /* open the devices ttymon monitors */
    Retry = TRUE;
    while (Retry) {
        Retry = FALSE;
        for (tp = PMtab; tp; tp = tp->p_next) {
            if ((tp->p_status > 0) && (tp->p_fd == 0) &&
                (tp->p_pid == 0) && !(tp->p_ttyflags & I_FLAG) &&
                (!((State == PM_DISABLED) &&
                ((tp->p_dmsg == NULL)||(*(tp->p_dmsg) == '\0'))))) {
                open_device(tp);
                if (tp->p_fd > 0)
                    got_carrier(tp);
            }
        }
    }
    Initialized = TRUE;
}

static  void    free_defs();

/*
 *  open_all - open devices in pmtab if the entry is
 *           - valid, fd = 0, and pid = 0
 */
static void
open_all()
{
    struct  pmtab   *tp;
    int check_modtime;
    sigset_t cset;
    sigset_t tset;

#ifdef  DEBUG
    debug("in open_all");
#endif
    check_modtime = TRUE;

    for (tp = PMtab; tp; tp = tp->p_next) {
        if ((tp->p_status > 0) && (tp->p_fd == 0) &&
            (tp->p_pid == 0) &&
            !(tp->p_ttyflags & I_FLAG) && (!((State == PM_DISABLED) &&
            ((tp->p_dmsg == NULL)||(*(tp->p_dmsg) == '\0'))))) {
            /*
             * if we have not check modification time and
             * /etc/ttydefs was modified, need to re-read it
             */
            if (check_modtime && mod_ttydefs()) {
                check_modtime = FALSE;
                (void) sigprocmask(SIG_SETMASK, NULL, &cset);
                tset = cset;
                (void) sigaddset(&tset, SIGCLD);
                (void) sigprocmask(SIG_SETMASK, &tset, NULL);
                free_defs();
#ifdef  DEBUG
                debug("/etc/ttydefs is modified, re-read it");
#endif
                read_ttydefs(NULL, FALSE);
                (void) sigprocmask(SIG_SETMASK, &cset, NULL);
            }
            open_device(tp);
            if (tp->p_fd > 0)
                got_carrier(tp);
        } else if (((tp->p_status == LOCKED) ||
            (tp->p_status == SESSION) ||
            (tp->p_status == UNACCESS)) &&
            (tp->p_fd > 0) &&
            (!((State == PM_DISABLED) &&
            ((tp->p_dmsg == NULL)||(*(tp->p_dmsg) == '\0'))))) {
            if (check_modtime && mod_ttydefs()) {
                check_modtime = FALSE;
                (void) sigprocmask(SIG_SETMASK, NULL, &cset);
                tset = cset;
                (void) sigaddset(&tset, SIGCLD);
                (void) sigprocmask(SIG_SETMASK, &tset, NULL);
                free_defs();
#ifdef  DEBUG
                debug("/etc/ttydefs is modified, re-read it");
#endif
                read_ttydefs(NULL, FALSE);
                (void) sigprocmask(SIG_SETMASK, &cset, NULL);
            }
            tp->p_status = VALID;
            open_device(tp);
            if (tp->p_fd > 0)
                got_carrier(tp);
        }
    }
}

void
set_softcar(pmptr)
struct  pmtab   *pmptr;
{

    int fd, val = 0;

#ifdef  DEBUG
    debug("in set_softcar");
#endif
    /*
     * If soft carrier is not set one way or
     * the other, leave it alone.
     */
    if (*pmptr->p_softcar == '\0')
        return;

    if (*pmptr->p_softcar == 'y')
        val = 1;

    if ((fd = open(pmptr->p_device, O_RDONLY|O_NONBLOCK|O_NOCTTY)) < 0) {
        log("open (%s) failed: %s", pmptr->p_device, strerror(errno));
        return;
    }

    if (ioctl(fd, TIOCSSOFTCAR, &val) < 0)
        log("set soft-carrier (%s) failed: %s", pmptr->p_device,
            strerror(errno));

    close(fd);
}


/*
 *  open_device(pmptr)  - open the device
 *              - check device lock
 *              - change owner of device
 *              - push line disciplines
 *              - set termio
 */

void
open_device(pmptr)
struct  pmtab   *pmptr;
{
    int fd, tmpfd;
    struct  sigaction   sigact;

#ifdef  DEBUG
    debug("in open_device");
#endif

    if (pmptr->p_status == GETTY) {
        revokedevaccess(pmptr->p_device, 0, 0, 0);

        if ((fd = open(pmptr->p_device, O_RDWR)) == -1)
            fatal("open (%s) failed: %s", pmptr->p_device,
                strerror(errno));

    } else {
        if (check_spawnlimit(pmptr) == -1) {
            pmptr->p_status = NOTVALID;
            log("service <%s> is respawning too rapidly",
                pmptr->p_tag);
            return;
        }
        if (pmptr->p_fd > 0) { /* file already open */
            fd = pmptr->p_fd;
            pmptr->p_fd = 0;
        } else if ((fd = open(pmptr->p_device, O_RDWR|O_NONBLOCK))
            == -1) {
            log("open (%s) failed: %s", pmptr->p_device,
                strerror(errno));
            if ((errno ==  ENODEV) || (errno == EBUSY)) {
                pmptr->p_status = UNACCESS;
                Nlocked++;
                if (Nlocked == 1) {
                    sigact.sa_flags = 0;
                    sigact.sa_handler = sigalarm;
                    (void) sigemptyset(&sigact.sa_mask);
                    (void) sigaction(SIGALRM, &sigact, NULL);
                    (void) alarm(ALARMTIME);
                }
            } else
                Retry = TRUE;
            return;
        }
        /* set close-on-exec flag */
        if (fcntl(fd, F_SETFD, 1) == -1)
            fatal("F_SETFD fcntl failed: %s", strerror(errno));

        if (tm_checklock(fd) != 0) {
            pmptr->p_status = LOCKED;
            (void) close(fd);
            Nlocked++;
            if (Nlocked == 1) {
                sigact.sa_flags = 0;
                sigact.sa_handler = sigalarm;
                (void) sigemptyset(&sigact.sa_mask);
                (void) sigaction(SIGALRM, &sigact, NULL);
                (void) alarm(ALARMTIME);
            }
            return;
        }
        if (check_session(fd) != 0) {
            if ((Initialized) && (pmptr->p_inservice != SESSION)) {
                log("Warning -- active session exists on <%s>",
                    pmptr->p_device);
            } else {
                /*
                 * this may happen if a service is running
                 * and ttymon dies and is restarted,
                 * or another process is running on the
                 * port.
                 */
                pmptr->p_status = SESSION;
                pmptr->p_inservice = 0;
                (void) close(fd);
                Nlocked++;
                if (Nlocked == 1) {
                    sigact.sa_flags = 0;
                    sigact.sa_handler = sigalarm;
                    (void) sigemptyset(&sigact.sa_mask);
                    (void) sigaction(SIGALRM, &sigact,
                        NULL);
                    (void) alarm(ALARMTIME);
                }
                return;
            }
        }
        pmptr->p_inservice = 0;
    }

    if (pmptr->p_ttyflags & H_FLAG) {
        /* drop DTR */
        (void) hang_up_line(fd);
        /*
         * After hang_up_line, the stream is in STRHUP state.
         * We need to do another open to reinitialize streams
         * then we can close one fd
         */
        if ((tmpfd = open(pmptr->p_device, O_RDWR|O_NONBLOCK)) == -1) {
            log("open (%s) failed: %s", pmptr->p_device,
                strerror(errno));
            Retry = TRUE;
            (void) close(fd);
            return;
        }
        (void) close(tmpfd);
    }

#ifdef DEBUG
    debug("open_device (%s), fd = %d", pmptr->p_device, fd);
#endif

    /* Change ownership of the tty line to root/uucp and */
    /* set protections to only allow root/uucp to read the line. */

    if (pmptr->p_ttyflags & (B_FLAG|C_FLAG))
        (void) fchown(fd, Uucp_uid, Tty_gid);
    else
        (void) fchown(fd, ROOTUID, Tty_gid);
    (void) fchmod(fd, 0620);

    if ((pmptr->p_modules != NULL)&&(*(pmptr->p_modules) != '\0')) {
        if (push_linedisc(fd, pmptr->p_modules, pmptr->p_device)
            == -1) {
            Retry = TRUE;
            (void) close(fd);
            return;
        }
    }

    if (initial_termio(fd, pmptr) == -1)  {
        Retry = TRUE;
        (void) close(fd);
        return;
    }

    di_devperm_logout((const char *)pmptr->p_device);
    pmptr->p_fd = fd;
}

/*
 *  set_poll(fdp)   - put all fd's in a pollfd array
 *          - set poll event to POLLIN and POLLMSG
 *          - return number of fd to be polled
 */

static  int
set_poll(fdp)
struct pollfd *fdp;
{
    struct  pmtab   *tp;
    int     nfd = 0;

    for (tp = PMtab; tp; tp = tp->p_next) {
        if (tp->p_fd > 0)  {
            fdp->fd = tp->p_fd;
            fdp->events = POLLIN;
            fdp++;
            nfd++;
        }
    }
    return (nfd);
}

/*
 *  check_spawnlimit    - return 0 if spawnlimit is not reached
 *              - otherwise return -1
 */
static  int
check_spawnlimit(pmptr)
struct  pmtab   *pmptr;
{
    time_t  now;

    (void) time(&now);
    if (pmptr->p_time == 0L)
        pmptr->p_time = now;
    if (pmptr->p_respawn >= SPAWN_LIMIT) {
        if ((now - pmptr->p_time) < SPAWN_INTERVAL) {
            pmptr->p_time = now;
            pmptr->p_respawn = 0;
            return (-1);
        }
        pmptr->p_time = now;
        pmptr->p_respawn = 0;
    }
    pmptr->p_respawn++;
    return (0);
}

/*
 * mod_ttydefs  - to check if /etc/ttydefs has been modified
 *      - return TRUE if file modified
 *      - otherwise, return FALSE
 */
static  int
mod_ttydefs()
{
    struct  stat    statbuf;
    extern  long    Mtime;
    if (stat(TTYDEFS, &statbuf) == -1) {
        /* if stat failed, don't bother reread ttydefs */
        return (FALSE);
    }
    if ((long)statbuf.st_mtime != Mtime) {
        Mtime = (long)statbuf.st_mtime;
        return (TRUE);
    }
    return (FALSE);
}

/*
 *  free_defs - free the Gdef table
 */
static  void
free_defs()
{
    int i;
    struct  Gdef    *tp;
    tp = &Gdef[0];
    for (i = 0; i < Ndefs; i++, tp++) {
        free(tp->g_id);
        free(tp->g_iflags);
        free(tp->g_fflags);
        free(tp->g_nextid);
        tp->g_id = NULL;
        tp->g_iflags = NULL;
        tp->g_fflags = NULL;
        tp->g_nextid = NULL;
    }
    Ndefs = 0;
}

/*
 * struct Gdef *get_speed(ttylabel)
 *  - search "/etc/ttydefs" for speed and term. specification
 *    using "ttylabel". If "ttylabel" is NULL, default
 *    to DEFAULT
 * arg:   ttylabel - label/id of speed settings.
 */

struct Gdef *
get_speed(char *ttylabel)
{
    register struct Gdef *sp;
    extern   struct Gdef DEFAULT;

    if ((ttylabel != NULL) && (*ttylabel != '\0')) {
        if ((sp = find_def(ttylabel)) == NULL) {
            log("unable to find <%s> in \"%s\"", ttylabel, TTYDEFS);
            sp = &DEFAULT; /* use default */
        }
    } else sp = &DEFAULT; /* use default */
    return (sp);
}

/*
 * setup_PCpipe()   - setup the pipe between Parent and Children
 *          - the pipe is used for a tmchild to send its
 *            pid to inform ttymon that it is about to
 *            invoke service
 *          - the pipe also serves as a mean for tmchild
 *            to detect failure of ttymon
 */
void
setup_PCpipe()
{
    int flag = 0;

    if (pipe(PCpipe) == -1)
        fatal("pipe() failed: %s", strerror(errno));

    /* set close-on-exec flag */
    if (fcntl(PCpipe[0], F_SETFD, 1) == -1)
        fatal("F_SETFD fcntl failed: %s", strerror(errno));

    if (fcntl(PCpipe[1], F_SETFD, 1) == -1)
        fatal("F_SETFD fcntl failed: %s", strerror(errno));

    /* set O_NONBLOCK flag */
    if (fcntl(PCpipe[0], F_GETFL, flag) == -1)
        fatal("F_GETFL failed: %s", strerror(errno));

    flag |= O_NONBLOCK;
    if (fcntl(PCpipe[0], F_SETFL, flag) == -1)
        fatal("F_SETFL failed: %s", strerror(errno));

    /* set message discard mode */
    if (ioctl(PCpipe[0], I_SRDOPT, RMSGD) == -1)
        fatal("I_SRDOPT RMSGD failed: %s", strerror(errno));

    /* register to receive SIGPOLL when data come */
    if (ioctl(PCpipe[0], I_SETSIG, S_INPUT) == -1)
        fatal("I_SETSIG S_INPUT failed: %s", strerror(errno));

#ifdef  DEBUG
    log("PCpipe[0]\t = %d", PCpipe[0]);
    log("PCpipe[1]\t = %d", PCpipe[1]);
#endif
}