dmake: do not set MAKEFLAGS=k

[unleashed/tickless.git] / usr / src / cmd / saf / sac.c

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

/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <ctype.h>
#include <signal.h>
#include <strings.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/stropts.h>
#include <sys/wait.h>
#include <unistd.h>
#include <utmpx.h>
#include <memory.h>
#include "msgs.h"
#include "extern.h"
#include <sac.h>
#include "misc.h"
#include "structs.h"

#include <security/pam_appl.h>

#define RESP    1               /* pollfail via no response to sanity poll */
#define DEATH   2               /* pollfail via child death */

/* signal whose dispositions will be changed */

static struct sigaction Sigpoll;        /* SIGPOLL */
static struct sigaction Sigcld;         /* SIGCLD */
static struct sigaction Sigalrm;        /* SIGALRM */
static sigset_t Origmask;               /* original signal mask */

void usage(void);
void initialize(void);
void startpms(void);
void readutmpx(void);
int startpm(struct sactab *);
void cleanutx(struct sactab *);
void account(struct sactab *, pid_t);
void startit(struct sactab *);
char **mkargv(struct sactab *);
void pollpms(void);
void reap(int);
void pollfail(struct sactab *, int);
void readpipe(void);
int validstate(unchar);
int mk_cmd_pipe(void);
void startpoll(void);



/*
 * main - scan args for sac, initialize everything, and wait for commands
 *        from sacadm via the command pipe
 */

int
main(int argc, char *argv[])
{
        int c;  /* place to hold options */
        struct sigaction sigact;        /* for signal handling */

        (void) sigprocmask(SIG_SETMASK, NULL, &Origmask);
        if (argc == 1)
                usage();
        (void) setpgrp();
        while ((c = getopt(argc, argv, "t:")) != -1) {
                switch (c) {
                case 't':
                        if (Stime != 0)
                                usage();
                        Stime = atoi(optarg);
                        if (Stime <= 0)
                                usage();
                        break;
                case '?':
                        usage();
                }
        }
        if (optind < argc)
                usage();

        initialize();
        sigact.sa_flags = 0;
        sigact.sa_handler = pollpms;
        (void) sigemptyset(&sigact.sa_mask);
        (void) sigaddset(&sigact.sa_mask, SIGALRM);
        (void) sigaction(SIGALRM, &sigact, &Sigalrm);

/*
 * minimize time spent in STARTING or UNKNOWN, pollpms() sets alarm
 */

        pollpms();
        for (;;)
                readpipe();
}


/*
 * usage - output a usage message on the console
 */

void
usage()
{
        FILE *fp;       /* scratch file pointer */

        fp = fopen("/dev/console", "w");
        if (fp)
                (void) fprintf(fp, "SAC: Usage: sac -t sanity_interval\n");
        exit(1);
}


/*
 * initialize - initialization stuff
 */


void
initialize()
{
        int ret;                        /* return code from doconfig() */
        struct sigaction sigact;        /* for signal handling */

        openlog();
        log("*** SAC starting ***");
#ifdef DEBUG
        opendebug();
        log("Debugging turned on");
#endif
        if (chdir(HOME) < 0)
                error(E_CHDIR, EXIT);

/*
 * pass an invalid fd, shouldn't be doing pushes and pops in this per-system
 * configuration script (_sysconfig)
 */

        if ((ret = doconfig(-1, SYSCONFIG, 0)) != 0) {
                if (ret == -1)
                        error(E_SYSCONF, EXIT);
                else {
                        (void) sprintf(Scratch,
                                        "Error in _sysconfig: line %d", ret);
                        log(Scratch);
                        error(E_BADSYSCONF, EXIT);
                }
        }

        sigact.sa_flags = 0;
        sigact.sa_handler = reap;
        (void) sigemptyset(&sigact.sa_mask);
        (void) sigaddset(&sigact.sa_mask, SIGCLD);
        (void) sigaction(SIGCLD, &sigact, &Sigcld);

/*
 * establish pipe for PMS to communicate with sac
 */

        if (access("_sacpipe", 0) != 0) {
                /* not there, create one */
                (void) umask(0);
                if (mknod("_sacpipe", S_IFIFO | 0600, 0) < 0)
                        error(E_NOPIPE, EXIT);
        }
        Sfd = open("_sacpipe", O_RDWR);
        if (Sfd < 0)
                error(E_NOPIPE, EXIT);

/*
 * establish pipe for sacadm to communicate with sac
 */

        Cfd = mk_cmd_pipe();

/*
 * read in _sactab, but don't start port monitors as a by-product
 * since we may be in recovery - start them explicitly instead
 */

        read_table(FALSE);
        startpoll();
        startpms();
}


/*
 * startpms - start initial set of port monitors
 */


void
startpms()
{
        struct sactab *sp;      /* working pointer */
        int rflag;                      /* recovery flag */
        pid_t checklock();

/*
 * check to see if we're really a recovering SAC (if any port monitors hold
 * locks, assume that we're in recovery), if so, start differently
 */

        rflag = 0;
        for (sp = Sactab; sp; sp = sp->sc_next) {
                if (checklock(sp)) {
                        rflag = 1;
                        sp->sc_sstate = sp->sc_pstate = UNKNOWN;
                        sp->sc_ok = 1;
                        sp->sc_exit = 0;
                        (void) sprintf(Scratch, "%s/_pmpipe", sp->sc_tag);
                        sp->sc_fd = open(Scratch, O_RDWR);
                        if (sp->sc_fd < 0) {

/*
 * if we get into here, we're in deep trouble.  PM seems to be running
 * and we're trying to recover, but we can't talk to it.  Unfortunately,
 * there's not much that can be done other than to try and restore a
 * sane state.  By setting sp->sc_ok to 0, this will look like a poll failure
 * and if sp->rs_rsmax > 0, PM will be restarted.
 */

                                (void) sprintf(Scratch,
                                "Could not open _pmpipe for port monitor <%s>",
                                        sp->sc_tag);
                                log(Scratch);
                                (void) sendsig(sp, SIGTERM);
                                sp->sc_ok = 0;
                        }
                }
        }
        if (rflag) {
                readutmpx();
                log("SAC in recovery");
                return;
        }

/*
 * normal startup
 */

        for (sp = Sactab; sp; sp = sp->sc_next) {
                if (sp->sc_flags & X_FLAG) {
                        /* System Administator specified don't start */
                        continue;
                }
                (void) startpm(sp);
        }
}


/*
 * readutmpx - read the utmpx file to find out the ids of running port
 *              monitors (only called during a recover start up).  Note:
 *              after a sac failure, init will inherit all of the port
 *              monitors and should get the SIGCLD's if they die (and
 *              will clean up).  This is mainly for stuck processes,
 *              although init would get the SIGCLD when the stuckie gets
 *              killed, it doesn't hurt to have the sac check.  This is
 *              only done once.
 *
 */


void
readutmpx()
{
        struct sactab *sp;      /* working pointer */
        struct sactab *savesp;  /* rembered port monitor match */
        struct utmpx *uxp;      /* working pointer */

        setutxent();
        while (uxp = getutxent()) {
                /* we're only interested in login processes */
                if (uxp->ut_type != LOGIN_PROCESS)
                        continue;
                if (uxp->ut_user[sizeof (uxp->ut_user) - 1] == '\0') {

/*
 * possible port monitor and name is short enough to do a normal compare
 */

                        sp = findpm(uxp->ut_user);
                        if (sp && (sp->sc_sstate == UNKNOWN)) {
                                /* found one */
                                (void) memcpy(sp->sc_utid, uxp->ut_id, IDLEN);
                                sp->sc_pid = uxp->ut_pid;
                        }
                } else {

/*
 * possible port monitor name, but it could have been truncated.  If
 * a match is found on a unique prefix, then it should be the correct
 * entry.  If an ambiguity is found, ignore the entry, init will clean
 * up the entry if it dies.
 */

                        savesp = NULL;
                        for (sp = Sactab; sp; sp = sp->sc_next) {
                                if (strncmp(uxp->ut_user, sp->sc_tag,
                                    sizeof (uxp->ut_user)) == 0) {
                                        if (savesp) {
                                                /* already found a match */
                                                savesp = NULL;
                                                (void) sprintf(Scratch,
                                                "ambiguous utmpx entry <%.8s>",
                                                        sp->sc_tag);
                                                log(Scratch);
                                                break;
                                        } else {
                                                savesp = sp;
                                        }
                                }
                        }
                        if (savesp && (savesp->sc_sstate == UNKNOWN)) {
                                /* found it */
                                (void) memcpy(savesp->sc_utid, uxp->ut_id,
                                                                IDLEN);
                                savesp->sc_pid = uxp->ut_pid;
                        }
                }
        }
        endutxent();
}


/*
 * startpm - start a particular PM, return code:
 *              -1: _pid file locked
 *              -2: any other reason
 *
 *      args:   sp - pointer to sac's port monitor information for
 *                   designated port monitor
 */

int
startpm(struct sactab *sp)
{
        sigset_t cset;          /* for signal handling */
        sigset_t tset;          /* for signal handling */
        pid_t pid;              /* pid of new port monitor */
        pid_t checklock();

#ifdef DEBUG
        debug("in startpm");
#endif
        if (checklock(sp)) {
                (void) sprintf(Scratch,
                        "could not start <%s> - _pid file locked", sp->sc_tag);
                log(Scratch);
                return (-1);
        }

        (void) sprintf(Scratch, "%s/_pmpipe", sp->sc_tag);
        if (access(Scratch, 0) != 0) {
                /* not there, create one */
                (void) umask(0);
                if (mknod(Scratch, S_IFIFO | 0600, 0) < 0) {
                        (void) sprintf(Scratch,
                "Could not create _pmpipe for port monitor <%s>, errno is %d",
                        sp->sc_tag, errno);
                        log(Scratch);
                        return (-2);
                }
        }
        sp->sc_fd = open(Scratch, O_RDWR);
        if (sp->sc_fd < 0) {
                (void) sprintf(Scratch,
                "Could not open _pmpipe for port monitor <%s>, errno is %d",
                        sp->sc_tag, errno);
                log(Scratch);
                return (-2);
        }

        /* in case child dies too quickly */
        (void) sigprocmask(SIG_SETMASK, NULL, &cset);
        tset = cset;
        (void) sigaddset(&tset, SIGCLD);
        (void) sigprocmask(SIG_SETMASK, &tset, NULL);
        if ((pid = fork()) < 0) {
                (void) sprintf(Scratch,
                        "Could not fork port monitor <%s>", sp->sc_tag);
                log(Scratch);
                return (-2);
        } else if (!pid) {
                startit(sp);
                /* no return */
        }

/*
 * clean up old utmpx if its there
 */

        cleanutx(sp);

/*
 * create a utmpx entry and set initial states
 */

        account(sp, pid);
        sp->sc_pstate = STARTING;
        if (sp->sc_lstate == NOTRUNNING)
                sp->sc_sstate = (sp->sc_flags & D_FLAG) ? DISABLED : ENABLED;
        else
                sp->sc_sstate = sp->sc_lstate;
        sp->sc_ok = 1;
        sp->sc_exit = 0;
        sp->sc_pid = pid;
        /* ok to take signals now that the table is up-to-table */
        (void) sigprocmask(SIG_SETMASK, &cset, NULL);
        return (0);
}


/*
 * cleanutx - clean out a utmpx record for a port monitor
 *
 *      args:   sp - pointer to sac's port monitor information for
 *                   designated port monitor
 */


void
cleanutx(struct sactab *sp)
{
        int i;                   /* scratch variable */
        int zerocheck;            /* scratch variable */
        char buf[SIZE];          /* scratch buffer */
        pam_handle_t *pamh;             /* PAM auth descriptor */
        struct utmpx ut;
        struct utmpx *up;
        int pid;
        char user[sizeof (up->ut_user) + 1];
        char ttyn[sizeof (up->ut_line) + 1];
        char rhost[sizeof (up->ut_host) + 1];
/*
 * check to see if there is a utmpx entry to clean up (indicated by a non
 * zero utmpx id
 */
        zerocheck = 0;
        for (i = 0; i < IDLEN; ++i) {
                zerocheck += sp->sc_utid[i];
        }
        if (zerocheck == 0)
                return;

        pid = sp->sc_pid;
        setutxent();
        while (up = getutxent()) {
                if (up->ut_pid == pid) {
                        if (up->ut_type == DEAD_PROCESS) {
                                /*
                                 * Cleaned up elsewhere.
                                 */
                                break;
                        }
                        strncpy(user, up->ut_user, sizeof (up->ut_user));
                        user[sizeof (up->ut_user)] = '\0';
                        strncpy(ttyn, up->ut_line, sizeof (up->ut_line));
                        ttyn[sizeof (up->ut_line)] = '\0';
                        strncpy(rhost, up->ut_host, sizeof (up->ut_host));
                        rhost[sizeof (up->ut_host)] = '\0';

                        if ((pam_start("sac", user, NULL, &pamh)) ==
                                                                PAM_SUCCESS) {
                                (void) pam_set_item(pamh, PAM_TTY, ttyn);
                                (void) pam_set_item(pamh, PAM_RHOST, rhost);
                                (void) pam_close_session(pamh, 0);
                                pam_end(pamh, PAM_SUCCESS);
                        }

                        up->ut_type = DEAD_PROCESS;
                        up->ut_exit.e_termination = WTERMSIG(sp->sc_exit);
                        up->ut_exit.e_exit = WEXITSTATUS(sp->sc_exit);
                        if (sp->sc_utid != NULL)
                                (void) memcpy(up->ut_id, sp->sc_utid,
                                        sizeof (up->ut_id));
                        (void) time(&up->ut_tv.tv_sec);
                        if (modutx(up) == NULL) {
                                /*
                                 * Since modutx failed we'll
                                 * write out the new entry
                                 * ourselves.
                                 */
                                (void) pututxline(up);
                                updwtmpx("wtmpx", up);
                        }
                        break;
                }
        }
        endutxent();
}

/*
 * account - create a utmp record for a port monitor
 *
 *      args:   pid - process id of port monitor
 */


void
account(struct sactab *sp, pid_t pid)
{
        struct utmpx utmpx;                     /* prototype utmpx entry */
        struct utmpx *up = &utmpx;              /* and a pointer to it */

        (void) memset(up, '\0', sizeof (utmpx));
        (void) strncpy(up->ut_user, sp->sc_tag, sizeof (up->ut_user));
        up->ut_pid = pid;
        up->ut_type = LOGIN_PROCESS;
        up->ut_id[0] = 'P';
        up->ut_id[1] = 'M';
        up->ut_id[2] = SC_WILDC;
        up->ut_id[3] = SC_WILDC;
        (void) time(&up->ut_xtime);
        if (makeutx(up) == NULL) {
                log("Could not create utmpx entry");
                (void) memset(sp->sc_utid, '\0', IDLEN);
        } else {
                (void) memcpy(sp->sc_utid, up->ut_id, IDLEN);
        }
}


/*
 * startit - finish starting a particular port monitor, establish environment,
 *              etc. (Note: this is the child at this point)
 *
 *      args:   sp - pointer to sac's port monitor information for
 *                   designated port monitor
 */


void
startit(struct sactab *sp)
{
        static char istate[SIZE];       /* place to put ISTATE env var. */
        static char pmtag[SIZE];        /* place to put PMTAG env var. */
        char **argvp;                   /* arglist for PM */
        int i;                          /* loop control variable */
        long ndesc;                     /* # of file descriptors configured */
        int ret;                        /* return value from doconfig */
        sigset_t cset;                  /* for signal handling */
        sigset_t tset;                  /* for signal handling */

/*
 * establish the home directory
 */

        if (chdir(sp->sc_tag) < 0) {
                (void) sprintf(Scratch,
                        "Cannot chdir to <%s/%s>, port monitor not started",
                        HOME, sp->sc_tag);
                log(Scratch);
                exit(1);
        }

/*
 * interpret the configuration script, pass an invalid fd, shouldn't be
 * doing pushes and pops in this script
 */

        (void) sigprocmask(SIG_SETMASK, NULL, &cset);
        tset = cset;
        (void) sigaddset(&tset, SIGCLD);
        (void) sigprocmask(SIG_SETMASK, &tset, NULL);
        if ((ret = doconfig(-1, "_config", 0)) != 0) {
                if (ret == -1) {
                        (void) sprintf(Scratch,
                                "system error in _config script for <%s>",
                                sp->sc_tag);
                        log(Scratch);
                        exit(1);
                } else {
                        (void) sprintf(Scratch,
                                "Error in _config script for <%s>: line %d",
                                sp->sc_tag, ret);
                        log(Scratch);
                        exit(1);
                }
        }

/*
 * add the promised environment variables
 */

        if (sp->sc_lstate == NOTRUNNING)
                (void) sprintf(istate, "ISTATE=%s",
                        (sp->sc_flags & D_FLAG) ? "disabled" : "enabled");
        else
                (void) sprintf(istate, "ISTATE=%s",
                        (sp->sc_lstate == DISABLED) ? "disabled" : "enabled");
        if (putenv(istate)) {
                (void) sprintf(Scratch,
                        "can't expand port monitor <%s> environment",
                        sp->sc_tag);
                log(Scratch);
                exit(1);
        }
        (void) sprintf(pmtag, "PMTAG=%s", sp->sc_tag);
        if (putenv(pmtag)) {
                (void) sprintf(Scratch,
                        "can't expand port monitor <%s> environment",
                        sp->sc_tag);
                log(Scratch);
                exit(1);
        }

/*
 * build an argv
 */

        argvp = mkargv(sp);

        (void) sprintf(Scratch, "starting port monitor <%s>", sp->sc_tag);
        log(Scratch);
        ndesc = ulimit(4, 0L);
        for (i = 0; i < ndesc; i++)
                (void) fcntl(i, F_SETFD, 1);
        /* restore orignal handlers and mask */
        (void) sigaction(SIGPOLL, &Sigpoll, NULL);
        (void) sigaction(SIGCLD, &Sigcld, NULL);
        (void) sigaction(SIGALRM, &Sigalrm, NULL);
        (void) sigprocmask(SIG_SETMASK, &Origmask, NULL);
        (void) execve(argvp[0], argvp, environ);
        (void) sprintf(Scratch, "exec of port monitor <%s> failed", sp->sc_tag);
        log(Scratch);
        exit(1);
}


/*
 * mkargv - Given a pointer to a struct sactab, construct argv
 *              for an exec system call.
 *
 *      args:   sp - pointer to sac's port monitor information for
 *                   designated port montior
 */


#define NARGS   50      /* max # of args */

static char *newargv[NARGS];    /* place for argv list */
static char *delim = " \t'\"";  /* delimiter list */

char **
mkargv(struct sactab *sp)
{
        char **argvp = newargv;                 /* scratch pointer */
        char *p = sp->sc_cmd;                   /* working pointer */
        char delch;                             /* delimiter seen */
        char *savep;                            /* scratch pointer */
        char *tp;                               /* scratch pointer */

        *argvp = 0;
        savep = p;
        while (p && *p) {
                if (p = strpbrk(p, delim)) {
                        switch (*p) {
                        case ' ':
                        case '\t':
                                /* "normal" cases */
                                *p++ = '\0';
                                *argvp++ = savep;
                                /* zap trailing white space */
                                while (isspace(*p))
                                        p++;
                                savep = p;
                                break;
                        case '"':
                        case '\'':
                                /* found a string */
                                delch = *p; /* remember the delimiter */
                                savep = ++p;

/*
 * We work the string in place, embedded instances of the string delimiter,
 * i.e. \" must have the '\' removed.  Since we'd have to do a compare to
 * decide if a copy were needed, it's less work to just do the copy, even
 * though it is most likely unnecessary.
 */

                                tp = p;
                                for (;;) {
                                        if (*p == '\0') {
                                                (void) sprintf(Scratch,
        "invalid command line, non-terminated string for port monitor %s",
                                                        sp->sc_tag);
                                                log(Scratch);
                                                exit(1);
                                        }
                                        if (*p == delch) {
                                                if (*(tp - 1) == '\\') {
                                                        /* \delim */
                                                        *(tp - 1) = *p;
                                                        p++;
                                                } else { /* end of string */
                                                        *tp = 0;
                                                        *argvp++ = savep;
                                                        p++;
                                                /* zap trailing white space */
                                                        while (isspace(*p))
                                                                p++;
                                                        savep = p;
                                                        break;
                                                }
                                        } else {
                                                *tp++ = *p++;
                                        }
                                }
                                break;
                        default:
                                log("Internal error in parse routine");
                                exit(1);
                        }
                }
                else
                        *argvp++ = savep;
        }
        *argvp = 0;
        return (newargv);
}


/*
 * pollpms - send out sanity polls, if sc_sstate and sc_pstate are
 *      the same (everyone agrees on the state) or if SAC thinks PM
 *      should be stopping, send out a status message;
 *      otherwise, send out a message indicating the state the SAC
 *      thinks the PM should be entering
 */

void
pollpms()
{
        struct sactab *sp;      /* working pointer */
        struct sacmsg sacmsg;           /* message to send to PM */

#ifdef DEBUG
        debug("alarm went off");
#endif
        for (sp = Sactab; sp; sp = sp->sc_next) {
                if (sp->sc_pstate == NOTRUNNING || sp->sc_pstate == FAILED) {
                        /* don't bother if no one is home */
                        continue;
                }
                if (sp->sc_ok == 0) {
                        /* PM has stopped responding */
                        pollfail(sp, RESP);
                        continue;
                }

/*
 * note - if we're in recovery, a SC_STATUS message is sent
 * (sc_sstate = UNKNOWN and sc_pstate = UNKNOWN)
 */

                if (sp->sc_sstate == sp->sc_pstate) {
                        sacmsg.sc_type = SC_STATUS;
                        sacmsg.sc_size = 0;
                } else {
                        switch (sp->sc_sstate) {
                        case ENABLED:
                                sacmsg.sc_type = SC_ENABLE;
                                sacmsg.sc_size = 0;
                                break;
                        case DISABLED:
                                sacmsg.sc_type = SC_DISABLE;
                                sacmsg.sc_size = 0;
                                break;
                        case STARTING:
                        case STOPPING:
                        case NOTRUNNING:
                        case FAILED:
                        case UNKNOWN:
                                /*
                                 * if NOTRUNNING or FAILED, PM will probably
                                 * not respond to poll, that's how we detect
                                 * that it's gone
                                 */
                                sacmsg.sc_type = SC_STATUS;
                                sacmsg.sc_size = 0;
                                break;
                        default:
                                error(E_BADSTATE, EXIT);
                        }
                }

                /* send the message */
                sendpmmsg(sp, &sacmsg);
                sp->sc_ok = 0;
        }
        (void) alarm(Stime);
}


/*
 * reap - clean up dead children, equivalent to a "fast" poll failure
 *
 *      args:   signo - signal #
 */

void
reap(int signo)
{
        struct sactab *sp;              /* working pointer */
        pid_t pid;                      /* returned pid from wait */
        int status;                     /* returned status from wait */

        pid = wait(&status);
        for (sp = Sactab; sp; sp = sp->sc_next) {
                if (sp->sc_pid == pid)
                        break;
        }
        if (sp == NULL) {
                /* not from a port monitor we know about */
                return;
        }
        sp->sc_exit = status;
        /* only call pollfail for "stuck" and stopping processes */
        if (sp->sc_pstate != NOTRUNNING && sp->sc_pstate != FAILED)
                pollfail(sp, DEATH);
}


/*
 * pollfail - handle the case where a PM stops responding to a sanity poll
 *
 *      args:   sp - pointer to sac's port monitor information for
 *                   designated port monitor
 *              reason - RESP or DEATH (indicates why pollfail called)
 */


void
pollfail(struct sactab *sp, int reason)
{
        char buf[SIZE];                 /* scratch buffer */
        sigset_t cset;                  /* for signal handling */
        sigset_t tset;                  /* for signal handling */

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

/* first, remove the utmpx entry and clean up any links */

        cleanutx(sp);

        if (sp->sc_pstate == STOPPING) {
                (void) sprintf(buf, "<%s> has stopped", sp->sc_tag);
                log(buf);
                sp->sc_pstate = NOTRUNNING;
                sp->sc_lstate = NOTRUNNING;
                (void) close(sp->sc_fd);
        } else {

/*
 * PM in trouble - if it's still there, try to put it out of its misery
 * We play with SIGCLD here to that after SIGKILL is sent, the catcher
 * routine reap() is not called until we're ready (note: when a catcher
 * is established for SIGCLD and any zombies are present, the signal is
 * immediately received)
 */

                (void) sigprocmask(SIG_SETMASK, NULL, &cset);
                tset = cset;
                (void) sigaddset(&tset, SIGCLD);
                (void) sigprocmask(SIG_SETMASK, &tset, NULL);
                (void) sendsig(sp, SIGKILL);
                if (sp->sc_rscnt < sp->sc_rsmax) {
                        /* try to restart it */
                        if (reason == RESP)
                                (void) sprintf(buf,
        "<%s> stopped responding to sanity polls - trying to restart",
                                        sp->sc_tag);
                        else
                                (void) sprintf(buf,
                                        "<%s> has died - trying to restart",
                                        sp->sc_tag);
                        log(buf);
                        sp->sc_rscnt++;
                        (void) close(sp->sc_fd);
                        (void) startpm(sp);
                } else {
                        sp->sc_sstate = sp->sc_pstate = FAILED;
                        (void) close(sp->sc_fd);
                        (void) sprintf(buf, "<%s> has FAILED", sp->sc_tag);
                        log(buf);
                }
        }
        (void) sigprocmask(SIG_SETMASK, &cset, NULL);
}


/*
 * readpipe - read messages from _sacpipe
 */


void
readpipe()
{
        struct pmmsg pmmsg;                     /* incoming message */
        struct pmmsg *pp = &pmmsg;              /* and a pointer to it */
        struct sactab *sp;                      /* working pointer */
        int ret;                                /* return value from read */

/*
 * This routine's main purpose is to maintain the state associated with
 * each of the known port monitors.  Because it may be confusing, following
 * is a brief discussion of what is happening.  Three different views of
 * a port monitor's state exist: sc_sstate, sc_pstate, and sc_lstate.
 * sc_sstate is the state in which the sac has been instructed to place
 * a port monitor.  sc_lstate is essentially a shadow of this field, however,
 * it will only take on the values ENABLED, DISABLED, and NOTRUNNING.
 * sc_lstate is used if a port monitor dies to restart it in the state in
 * which it was last running.  sc_pstate is the last state that the port
 * monitor reported itself in.  Note that if the administrator specifies
 * a state change, there is a window where sc_sstate and sc_pstate will
 * be different (until the port monitor enacts and acknowledges the change).
 *
 * These states interact with the polling loop to determine which message
 * should be sent to a port monitor.  If the states agree, an SC_STATUS
 * is sent.  If they disagree, the appropriate message to put the port
 * monitor in the correct state is sent (SC_ENABLE or SC_DISABLE).  sc_pstate
 * is the state that is reported back to an AC_STATUS request.  Finally,
 * when in recovery (sc_sstate and sc_pstate both = UNKNOWN), the sac will
 * take the port monitor's reported state as the true state.  This is the
 * only instance in which a port monitor can cause sc_sstate to change.
 */

        for (;;) {
                if (read(Sfd, pp, sizeof (pmmsg)) < 0) {
                        if (errno != EINTR)
                                error(E_BADREAD, EXIT);
                        continue;
                }

                while (pp->pm_size) {

/*
 * there's data after the header, unfortunately, we don't understand
 * any of it because only class 1 (no data) messages are defined.  Just
 * flush it
 */

                        ret = read(Sfd, Scratch,
                                (pp->pm_size > SIZE) ? (unsigned) SIZE :
                                                (unsigned) pp->pm_size);
                        if (ret < 0) {
                                if (errno != EINTR)
                                        error(E_BADREAD, EXIT);
                                continue;
                        }
                        else
                                pp->pm_size -= ret;
                }

                sp = findpm(pp->pm_tag);
                if (sp == NULL) {
                        log("message from unknown process");
                        continue;
                }
                switch (pp->pm_type) {
                case PM_UNKNOWN:
                        (void) sprintf(Scratch,
                                "port monitor <%s> didn't recognize message",
                                sp->sc_tag);
                        log(Scratch);
                        /* fall through */
                case PM_STATUS:
                        /*
                         * paranoia check, if port monitor reports garbage
                         * state, pretend it said UNKNOWN
                         */
                        if (!validstate(pp->pm_state)) {
                                pp->pm_state = UNKNOWN;
                                (void) sprintf(Scratch,
                                "port monitor <%s> reporting invalid state",
                                        sp->sc_tag);
                                log(Scratch);
                        }
                        if (sp->sc_sstate == sp->sc_pstate) {
                                /* everyone agrees on the current state */
                                if (sp->sc_sstate == UNKNOWN) {
                                        /* special case for recovery */
                                        sp->sc_sstate = pp->pm_state;
                                        sp->sc_pstate = pp->pm_state;
                                        if (pp->pm_state == ENABLED ||
                                                pp->pm_state == DISABLED)
                                        /* sc_lstate NOTRUNNING by default */
                                                sp->sc_lstate = pp->pm_state;
                                }
                                if (pp->pm_state != sp->sc_pstate) {
                                        /*
                                         * something isn't right here, PM
                                         * changed state without orders, try
                                         * to restore to correct state
                                         */
                                        sp->sc_pstate = pp->pm_state;
                                }
                        } else if (sp->sc_sstate == pp->pm_state) {
                                /* PM changed to state requested */
                                (void) sprintf(Scratch,
                        "port monitor <%s> changed state from %s to %s",
                                        sp->sc_tag, pstate(sp->sc_pstate),
                                        pstate(pp->pm_state));
                                log(Scratch);
                                sp->sc_pstate = pp->pm_state;
                        } else if (sp->sc_pstate != pp->pm_state) {
                                /*
                                 * something isn't right here, PM isn't
                                 * in the state it was, nor is it in the
                                 * state we just tried to put it in, try
                                 * to restore to correct state if we should
                                 */
                                if (sp->sc_pstate != STOPPING)
                                        sp->sc_pstate = pp->pm_state;
                        }
                        break;
                default:
                        (void) sprintf(Scratch,
                "port monitor <%s> sent an invalid message - ignoring it",
                                sp->sc_tag);
                        log(Scratch);
                        break;
                }
                /* no matter what, PM did answer the poll */
                sp->sc_ok = 1;
                /* Note the messages it understands */
                sp->sc_maxclass = pp->pm_maxclass;
        }
}


/*
 * validstate - determine if arg s a valid return state from a port monitor
 *      return 1 if ok, 0 otherwise
 *
 *      args:   state - state to be verified
 */
int
validstate(unchar state)
{
        switch (state) {
        case PM_ENABLED:
        case PM_DISABLED:
        case PM_STARTING:
        case PM_STOPPING:
                return (1);
        default:
                return (0);
        }
}


/*
 * mk_cmd_pipe - create the command pipe used by sacadm
 */

int
mk_cmd_pipe()
{
        int fds[2];                     /* pipe endpoints */
        int fd;                         /* scratch file descriptor */

        /* make sure there is a file here to mount on */
        (void) unlink(CMDPIPE);
        fd = open(CMDPIPE, O_RDWR | O_CREAT, 0600);
        if (fd < 0)
                error(E_CMDPIPE, EXIT);
        close(fd);
        if (pipe(fds) < 0)
                error(E_PIPE, EXIT);
        if (fattach(fds[0], CMDPIPE) < 0)
                error(E_FATTACH, EXIT);
        return (fds[1]);
}


/*
 * startpoll - enable polling on command pipe by setting up to catch SIGPOLL
 */


void
startpoll()
{
        struct sigaction sigact;        /* for signal handling */

        if (ioctl(Cfd, I_SETSIG, S_INPUT) < 0)
                error(E_SETSIG, EXIT);
        sigact.sa_flags = 0;
        sigact.sa_handler = sigpoll;
        (void) sigemptyset(&sigact.sa_mask);
        (void) sigaddset(&sigact.sa_mask, SIGPOLL);
        (void) sigaction(SIGPOLL, &sigact, &Sigpoll);
}