dmake: do not set MAKEFLAGS=k

[unleashed/tickless.git] / usr / src / cmd / sulogin / sulogin.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 2013 Nexenta Systems, Inc. All rights reserved.
 * Copyright (c) 2016 by Delphix. All rights reserved.
 */

/*
 * 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.
 *
 *      Copyright (c) 1987, 1988 Microsoft Corporation.
 *      All rights reserved.
 */

/*
 *      sulogin - special login program exec'd from init to let user
 *      come up single user, or go to default init state straight away.
 *
 *      Explain the scoop to the user, prompt for an authorized user
 *      name or ^D and then prompt for password or ^D.  If the password
 *      is correct, check if the user is authorized, if so enter
 *      single user. ^D exits sulogin, and init will go to default init state.
 *
 *      If /etc/passwd is missing, or there's no entry for root,
 *      go single user, no questions asked.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <sys/sysmsg_impl.h>
#include <sys/mkdev.h>
#include <sys/resource.h>
#include <sys/uadmin.h>
#include <sys/wait.h>
#include <sys/stermio.h>
#include <fcntl.h>
#include <termio.h>
#include <pwd.h>
#include <shadow.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <siginfo.h>
#include <utmpx.h>
#include <unistd.h>
#include <ucontext.h>
#include <string.h>
#include <strings.h>
#include <deflt.h>
#include <limits.h>
#include <errno.h>
#include <crypt.h>
#include <auth_attr.h>
#include <auth_list.h>
#include <nss_dbdefs.h>
#include <user_attr.h>
#include <sys/vt.h>
#include <sys/kd.h>

/*
 * Intervals to sleep after failed login
 */
#ifndef SLEEPTIME
#define SLEEPTIME       4       /* sleeptime before login incorrect msg */
#endif

#define SLEEPTIME_MAX   5       /* maximum sleeptime */

/*
 *      the name of the file containing the login defaults we deliberately
 *      use the same file as login(1)
 */

#define DEFAULT_LOGIN   "/etc/default/login"
#define DEFAULT_SULOGIN "/etc/default/sulogin"
#define DEFAULT_CONSOLE "/dev/console"

static char     shell[] = "/sbin/sh";
static char     su[]    = "/sbin/su.static";
static int      sleeptime       = SLEEPTIME;
static int      nchild = 0;
static pid_t    pidlist[10];
static pid_t    masterpid = 0;
static pid_t    originalpid = 0;
static struct sigaction sa;
static struct termio    ttymodes;

static char     *findttyname(int fd);
static char     *stripttyname(char *);
static char     *sulogin_getinput(char *, int);
static void     noop(int);
static void     single(const char *, char *);
static void     main_loop(char *, boolean_t);
static void     parenthandler();
static void     termhandler(int);
static void     setupsigs(void);
static int      pathcmp(char *, char *);
static void     doit(char *, char *);
static void     childcleanup(int);

#define ECHOON  0
#define ECHOOFF 1

/* ARGSUSED */
int
main(int argc, char **argv)
{
        struct spwd     *shpw;
        int             passreq = B_TRUE;
        int             flags;
        int             fd;
        char            *infop, *ptr, *p;
        pid_t           pid;
        int             bufsize;
        struct stat     st;
        char            cttyname[100];
        char            namedlist[500];
        char            scratchlist[500];
        dev_t           cttyd;

        if (geteuid() != 0) {
                (void) fprintf(stderr, "%s: must be root\n", argv[0]);
                return (EXIT_FAILURE);
        }

        /* Do the magic to determine the children */
        if ((fd = open(SYSMSG, O_RDONLY)) < 0)
                return (EXIT_FAILURE);

        /*
         * If the console supports the CIOCTTYCONSOLE ioctl, then fetch
         * its console device list.  If not, then we use the default
         * console name.
         */
        if (ioctl(fd, CIOCTTYCONSOLE, &cttyd) == 0) {
                if ((bufsize = ioctl(fd, CIOCGETCONSOLE, NULL)) < 0)
                        return (EXIT_FAILURE);

                if (bufsize > 0) {
                        if ((infop = calloc(bufsize, sizeof (char))) == NULL)
                                return (EXIT_FAILURE);

                        if (ioctl(fd, CIOCGETCONSOLE, infop) < 0)
                                return (EXIT_FAILURE);

                        (void) snprintf(namedlist, sizeof (namedlist), "%s %s",
                            DEFAULT_CONSOLE, infop);
                } else
                        (void) snprintf(namedlist, sizeof (namedlist), "%s",
                            DEFAULT_CONSOLE);
        } else {
                (void) snprintf(namedlist, sizeof (namedlist), "%s",
                    DEFAULT_CONSOLE);
                cttyd = NODEV;
        }

        /*
         * The attempt to turn the controlling terminals dev_t into a string
         * may not be successful, thus leaving the variable cttyname as a
         * NULL.  This occurs if during boot we find
         * the root partition (or some other partition)
         * requires manual fsck, thus resulting in sulogin
         * getting invoked.  The ioctl for CIOCTTYCONSOLE
         * called above returned NODEV for cttyd
         * in these cases.  NODEV gets returned when the vnode pointer
         * in our session structure is NULL.  In these cases it
         * must be assumed that the default console is used.
         *
         * See kernel/os/session.c:cttydev().
         */
        (void) strcpy(cttyname, DEFAULT_CONSOLE);
        (void) strcpy(scratchlist, namedlist);
        ptr = scratchlist;
        while (ptr != NULL) {
                p = strchr(ptr, ' ');
                if (p == NULL) {
                        if (stat(ptr, &st))
                                return (EXIT_FAILURE);
                        if (st.st_rdev == cttyd)
                                (void) strcpy(cttyname, ptr);
                        break;
                }
                *p++ = '\0';
                if (stat(ptr, &st))
                        return (EXIT_FAILURE);
                if (st.st_rdev == cttyd) {
                        (void) strcpy(cttyname, ptr);
                        break;
                }
                ptr = p;
        }

        /*
         * Use the same value of SLEEPTIME that login(1) uses.  This
         * is obtained by reading the file /etc/default/login using
         * the def*() functions.
         */

        if (defopen(DEFAULT_LOGIN) == 0) {

                /* ignore case */

                flags = defcntl(DC_GETFLAGS, 0);
                TURNOFF(flags, DC_CASE);
                (void) defcntl(DC_SETFLAGS, flags);

                if ((ptr = defread("SLEEPTIME=")) != NULL)
                        sleeptime = atoi(ptr);

                if (sleeptime < 0 || sleeptime > SLEEPTIME_MAX)
                        sleeptime = SLEEPTIME;

                (void) defopen(NULL);   /* closes DEFAULT_LOGIN */
        }

        /*
         * Use our own value of PASSREQ, separate from the one login(1) uses.
         * This is obtained by reading the file /etc/default/sulogin using
         * the def*() functions.
         */

        if (defopen(DEFAULT_SULOGIN) == 0) {
                if ((ptr = defread("PASSREQ=")) != NULL)
                        if (strcmp("NO", ptr) == 0)
                                passreq = B_FALSE;

                (void) defopen(NULL);   /* closes DEFAULT_SULOGIN */
        }

        if (passreq == B_FALSE)
                single(shell, NULL);

        /*
         * if no 'root' entry in /etc/shadow, give maint. mode single
         * user shell prompt
         */
        setspent();
        if ((shpw = getspnam("root")) == NULL) {
                (void) fprintf(stderr, "\n*** Unable to retrieve `root' entry "
                    "in shadow password file ***\n\n");
                single(shell, NULL);
        }
        endspent();
        /*
         * if no 'root' entry in /etc/passwd, give maint. mode single
         * user shell prompt
         */
        setpwent();
        if (getpwnam("root") == NULL) {
                (void) fprintf(stderr, "\n*** Unable to retrieve `root' entry "
                    "in password file ***\n\n");
                single(shell, NULL);
        }
        endpwent();
        /* process with controlling tty treated special */
        if ((pid = fork()) != (pid_t)0) {
                if (pid == -1)
                        return (EXIT_FAILURE);
                else {
                        setupsigs();
                        masterpid = pid;
                        originalpid = getpid();
                        /*
                         * init() was invoked from a console that was not
                         * the default console, nor was it an auxiliary.
                         */
                        if (cttyname[0] == '\0')
                                termhandler(0);
                                /* Never returns */

                        main_loop(cttyname, B_TRUE);
                        /* Never returns */
                }
        }
        masterpid = getpid();
        originalpid = getppid();
        pidlist[nchild++] = originalpid;

        sa.sa_handler = childcleanup;
        sa.sa_flags = 0;
        (void) sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGTERM, &sa, NULL);
        (void) sigaction(SIGHUP, &sa, NULL);
        sa.sa_handler = parenthandler;
        sa.sa_flags = SA_SIGINFO;
        (void) sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGUSR1, &sa, NULL);

        sa.sa_handler = SIG_IGN;
        sa.sa_flags = 0;
        (void) sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGCHLD, &sa, NULL);
        /*
         * If there isn't a password on root, then don't permit
         * the fanout capability of sulogin.
         */
        if (*shpw->sp_pwdp != '\0') {
                ptr = namedlist;
                while (ptr != NULL) {
                        p = strchr(ptr, ' ');
                        if (p == NULL) {
                                doit(ptr, cttyname);
                                break;
                        }
                        *p++ = '\0';
                        doit(ptr, cttyname);
                        ptr = p;
                }
        }
        if (pathcmp(cttyname, DEFAULT_CONSOLE) != 0) {
                if ((pid = fork()) == (pid_t)0) {
                        setupsigs();
                        main_loop(DEFAULT_CONSOLE, B_FALSE);
                } else if (pid == -1)
                        return (EXIT_FAILURE);
                pidlist[nchild++] = pid;
        }
        /*
         * When parent is all done, it pauses until one of its children
         * signals that its time to kill the underpriviledged.
         */
        (void) wait(NULL);

        return (0);
}

/*
 * These flags are taken from stty's "sane" table entries in
 * usr/src/cmd/ttymon/sttytable.c
 */
#define SET_IFLAG (BRKINT|IGNPAR|ISTRIP|ICRNL|IXON|IMAXBEL)
#define RESET_IFLAG (IGNBRK|PARMRK|INPCK|INLCR|IGNCR|IUCLC|IXOFF|IXANY)
#define SET_OFLAG (OPOST|ONLCR)
#define RESET_OFLAG (OLCUC|OCRNL|ONOCR|ONLRET|OFILL|OFDEL| \
        NLDLY|CRDLY|TABDLY|BSDLY|VTDLY|FFDLY)
#define SET_LFLAG (ISIG|ICANON|IEXTEN|ECHO|ECHOK|ECHOE|ECHOKE|ECHOCTL)
#define RESET_LFLAG (XCASE|ECHONL|NOFLSH|STFLUSH|STWRAP|STAPPL)

/*
 * Do the equivalent of 'stty sane' on the terminal since we don't know
 * what state it was in on startup.
 */
static void
sanitize_tty(int fd)
{
        (void) ioctl(fd, TCGETA, &ttymodes);
        ttymodes.c_iflag &= ~RESET_IFLAG;
        ttymodes.c_iflag |= SET_IFLAG;
        ttymodes.c_oflag &= ~RESET_OFLAG;
        ttymodes.c_oflag |= SET_OFLAG;
        ttymodes.c_lflag &= ~RESET_LFLAG;
        ttymodes.c_lflag |= SET_LFLAG;
        ttymodes.c_cc[VERASE] = CERASE;
        ttymodes.c_cc[VKILL] = CKILL;
        ttymodes.c_cc[VQUIT] = CQUIT;
        ttymodes.c_cc[VINTR] = CINTR;
        ttymodes.c_cc[VEOF] = CEOF;
        ttymodes.c_cc[VEOL] = CNUL;
        (void) ioctl(fd, TCSETAF, &ttymodes);
}

/*
 * Fork a child of sulogin for each of the auxiliary consoles.
 */
static void
doit(char *ptr, char *cttyname)
{
        pid_t   pid;

        if (pathcmp(ptr, DEFAULT_CONSOLE) != 0 &&
            pathcmp(ptr, cttyname) != 0) {
                if ((pid = fork()) == (pid_t)0) {
                        setupsigs();
                        main_loop(ptr, B_FALSE);
                } else if (pid == -1)
                        exit(EXIT_FAILURE);
                pidlist[nchild++] = pid;
        }
}

static int
pathcmp(char *adev, char *bdev)
{
        struct stat     st1;
        struct stat     st2;

        if (adev == NULL || bdev == NULL)
                return (1);

        if (strcmp(adev, bdev) == 0)
                return (0);

        if (stat(adev, &st1) || !S_ISCHR(st1.st_mode))
                return (1);

        if (stat(bdev, &st2) || !S_ISCHR(st2.st_mode))
                return (1);

        if (st1.st_rdev == st2.st_rdev)
                return (0);

        return (1);
}

/* Handlers for the children at initialization */
static void
setupsigs()
{
        sa.sa_handler = noop;
        sa.sa_flags = 0;
        (void) sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGINT, &sa, NULL);
        (void) sigaction(SIGQUIT, &sa, NULL);

        sa.sa_handler = termhandler;
        sa.sa_flags = 0;
        (void) sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGTERM, &sa, NULL);
        (void) sigaction(SIGKILL, &sa, NULL);
        (void) sigaction(SIGHUP, &sa, NULL);
}

static void
main_loop(char *devname, boolean_t cttyflag)
{
        int             fd, fb, i;
        char            *user = NULL;           /* authorized user */
        char            *pass;                  /* password from user */
        char            *cpass;                 /* crypted password */
        struct spwd     spwd;
        struct spwd     *lshpw;                 /* local shadow */
        char            shadow[NSS_BUFLEN_SHADOW];
        FILE            *sysmsgfd;

        for (i = 0; i < 3; i++)
                (void) close(i);
        if (cttyflag == B_FALSE) {
                if (setsid() == -1)
                        exit(EXIT_FAILURE);
        }
        if ((fd = open(devname, O_RDWR)) < 0)
                exit(EXIT_FAILURE);

        /*
         * In system maintenance mode, all virtual console instances
         * of the svc:/system/console-login service are not available
         * any more, and only the system console is available. So here
         * we always switch to the system console in case at the moment
         * the active console isn't it.
         */
        (void) ioctl(fd, VT_ACTIVATE, 1);

        if (fd != 0)
                (void) dup2(fd, STDIN_FILENO);
        if (fd != 1)
                (void) dup2(fd, STDOUT_FILENO);
        if (fd != 2)
                (void) dup2(fd, STDERR_FILENO);
        if (fd > 2)
                (void) close(fd);

        /* Stop progress bar and reset console mode to text */
        if ((fb = open("/dev/fb", O_RDONLY)) >= 0) {
                (void) ioctl(fb, KDSETMODE, KD_RESETTEXT);
                (void) close(fb);
        }

        sysmsgfd = fopen("/dev/sysmsg", "w");

        sanitize_tty(fileno(stdin));

        for (;;) {
                do {
                        (void) printf("\nEnter user name for system "
                            "maintenance (control-d to bypass): ");
                        user = sulogin_getinput(devname, ECHOON);
                        if (user == NULL) {
                                /* signal other children to exit */
                                (void) sigsend(P_PID, masterpid, SIGUSR1);
                                /* ^D, so straight to default init state */
                                exit(EXIT_FAILURE);
                        }
                } while (user[0] == '\0');
                (void) printf("Enter %s password (control-d to bypass): ",
                    user);

                if ((pass = sulogin_getinput(devname, ECHOOFF)) == NULL) {
                        /* signal other children to exit */
                        (void) sigsend(P_PID, masterpid, SIGUSR1);
                        /* ^D, so straight to default init state */
                        free(user);
                        exit(EXIT_FAILURE);
                }
                lshpw = getspnam_r(user, &spwd, shadow, sizeof (shadow));
                if (lshpw == NULL) {
                        /*
                         * the user entered doesn't exist, too bad.
                         */
                        goto sorry;
                }

                /*
                 * There is a special case error to catch here:
                 * If the password is hashed with an algorithm
                 * other than the old unix crypt the call to crypt(3c)
                 * could fail if /usr is corrupt or not available
                 * since by default /etc/security/crypt.conf will
                 * have the crypt_ modules located under /usr/lib.
                 * Or it could happen if /etc/security/crypt.conf
                 * is corrupted.
                 *
                 * If this happens crypt(3c) will return NULL and
                 * set errno to ELIBACC for the former condition or
                 * EINVAL for the latter, in this case we bypass
                 * authentication and just verify that the user is
                 * authorized.
                 */

                errno = 0;
                cpass = crypt(pass, lshpw->sp_pwdp);
                if (((cpass == NULL) && (lshpw->sp_pwdp[0] == '$')) &&
                    ((errno == ELIBACC) || (errno == EINVAL))) {
                        goto checkauth;
                } else if ((cpass == NULL) ||
                    (strcmp(cpass, lshpw->sp_pwdp) != 0)) {
                        goto sorry;
                }

checkauth:
                /*
                 * There is a special case error here as well.
                 * If /etc/user_attr is corrupt, getusernam("root")
                 * returns NULL.
                 * In this case, we just give access because this is similar
                 * to the case of root not existing in /etc/passwd.
                 */

                if ((getusernam("root") != NULL) &&
                    (chkauthattr(MAINTENANCE_AUTH, user) != 1)) {
                        goto sorry;
                }
                (void) fprintf(sysmsgfd, "\nsingle-user privilege "
                    "assigned to %s on %s.\n", user, devname);
                (void) sigsend(P_PID, masterpid, SIGUSR1);
                (void) wait(NULL);
                free(user);
                free(pass);
                single(su, devname);
                /* single never returns */

sorry:
                (void) printf("\nLogin incorrect or user %s not authorized\n",
                    user);
                free(user);
                free(pass);
                (void) sleep(sleeptime);
        }
}

/*
 * single() - exec shell for single user mode
 */

static void
single(const char *cmd, char *ttyn)
{
        struct utmpx    *u;
        char            found = B_FALSE;

        if (ttyn == NULL)
                ttyn = findttyname(STDIN_FILENO);

        /*
         * utmpx records on the console device are expected to be "console"
         * by other processes, such as dtlogin.
         */
        ttyn = stripttyname(ttyn);

        /* update the utmpx file. */
        while ((u = getutxent()) != NULL) {
                if (strcmp(u->ut_line, ttyn) == 0) {
                        u->ut_tv.tv_sec = time(NULL);
                        u->ut_type = USER_PROCESS;
                        u->ut_pid = getpid();
                        if (strcmp(u->ut_user, "root") != 0)
                                (void) strcpy(u->ut_user, "root");
                        (void) pututxline(u);
                        found = B_TRUE;
                        break;
                }
        }
        if (!found) {
                struct utmpx entryx;

                entryx.ut_tv.tv_sec = time(NULL);
                entryx.ut_type = USER_PROCESS;
                entryx.ut_pid = getpid();
                (void) strcpy(entryx.ut_user, "root");
                (void) strcpy(entryx.ut_line, ttyn);
                entryx.ut_tv.tv_usec = 0;
                entryx.ut_session = 0;
                entryx.ut_id[0] = 'c';
                entryx.ut_id[1] = 'o';
                entryx.ut_id[2] = 's';
                entryx.ut_id[3] = 'u';
                entryx.ut_syslen = 1;
                entryx.ut_host[0] = '\0';
                entryx.ut_exit.e_termination = WTERMSIG(0);
                entryx.ut_exit.e_exit = WEXITSTATUS(0);
                (void) pututxline(&entryx);
        }
        endutxent();
        (void) printf("Entering System Maintenance Mode\n\n");

        if (execl(cmd, cmd, "-", (char *)0) < 0)
                exit(EXIT_FAILURE);
}

/*
 * sulogin_getinput() - hacked from the standard PAM tty conversation
 *                      function getpassphrase() library version
 *                      so we can distinguish newline and EOF.
 *                      also don't need this routine to give a prompt.
 *
 * returns the password string, or NULL if the used typed EOF.
 */

static char *
sulogin_getinput(char *devname, int echooff)
{
        struct termio   ttyb;
        int             c;
        FILE            *fi;
        static char     input[PASS_MAX + 1];
        void            (*saved_handler)();
        char            *rval = input;
        int             i = 0;

        if ((fi = fopen(devname, "r")) == NULL) {
                fi = stdin;
        }

        saved_handler = signal(SIGINT, SIG_IGN);

        if (echooff) {
                ttyb = ttymodes;
                ttyb.c_lflag &= ~(ECHO | ECHOE | ECHONL);
                (void) ioctl(fileno(fi), TCSETAF, &ttyb);
        }

        /* get characters up to PASS_MAX, but don't overflow */
        while ((c = getc(fi)) != '\n' && (c != '\r')) {
                if (c == EOF && i == 0) {       /* ^D, no input */
                        rval = NULL;
                        break;
                }
                if (i < PASS_MAX) {
                        input[i++] = (char)c;
                }
        }
        input[i] = '\0';
        (void) fputc('\n', fi);
        if (echooff) {
                (void) ioctl(fileno(fi), TCSETAW, &ttymodes);
        }

        if (saved_handler != SIG_ERR)
                (void) signal(SIGINT, saved_handler);
        return (rval == NULL ? NULL : strdup(rval));
}

static char *
findttyname(int fd)
{
        char    *ttyn = ttyname(fd);

        if (ttyn == NULL)
                ttyn = "/dev/???";
        else {
                /*
                 * /dev/syscon and /dev/systty are usually links to
                 * /dev/console.  prefer /dev/console.
                 */
                if (((strcmp(ttyn, "/dev/syscon") == 0) ||
                    (strcmp(ttyn, "/dev/systty") == 0)) &&
                    access("/dev/console", F_OK))
                        ttyn = "/dev/console";
        }
        return (ttyn);
}

static char *
stripttyname(char *ttyn)
{
        /* saw off the /dev/ */
        if (strncmp(ttyn, "/dev/", sizeof ("/dev/") -1) == 0)
                return (ttyn + sizeof ("/dev/") - 1);
        else
                return (ttyn);
}


/* ARGSUSED */
static  void
noop(int sig)
{
        /*
         * This signal handler does nothing except return.  We use it
         * as the signal disposition in this program instead of
         * SIG_IGN so that we do not have to restore the disposition
         * back to SIG_DFL. Instead we allow exec(2) to set the
         * dispostion to SIG_DFL to avoid a race condition.
         */
}

/* ARGSUSED */
static void
parenthandler(int sig, siginfo_t *si, ucontext_t *uc)
{
        int i;

        /*
         * We get here if someone has successfully entered a password
         * from the auxiliary console and is getting the single-user shell.
         * When this happens, the parent needs to kill the children
         * that didn't get the shell.
         *
         */
        for (i = 0; i < nchild; i++) {
                if (pidlist[i] != si->__data.__proc.__pid)
                        (void) sigsend(P_PID, pidlist[i], SIGTERM);
        }
        sa.sa_handler = SIG_IGN;
        sa.sa_flags = 0;
        (void) sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGINT, &sa, NULL);
        (void) sigaction(SIGQUIT, &sa, NULL);
        (void) sigaction(SIGTERM, &sa, NULL);
        (void) wait(NULL);
}

/*
 * The master pid will get SIGTERM or SIGHUP from init, and then
 * has to make sure the shell isn't still running.
 */

/* ARGSUSED */
static  void
childcleanup(int sig)
{
        int i;

        /* Only need to kill the child that became the shell. */
        for (i = 0; i < nchild; i++) {
                /* Don't kill grandparent before it's necessary */
                if (pidlist[i] != getppid())
                        (void) sigsend(P_PID, pidlist[i], SIGHUP);
        }
}

/* ARGSUSED */
static  void
termhandler(int sig)
{
        FILE *fi;
        pid_t pid;

        /* Processes come here when they fail to receive the password. */
        if ((fi = fopen("/dev/tty", "r+")) == NULL)
                fi = stdin;
        else
                setbuf(fi, NULL);
        sanitize_tty(fileno(fi));
        /* If you're the controlling tty, then just wait */
        pid = getpid();
        if (pid == originalpid || pid == masterpid) {
                sa.sa_handler = SIG_IGN;
                sa.sa_flags = 0;
                (void) sigemptyset(&sa.sa_mask);
                (void) sigaction(SIGINT, &sa, NULL);
                (void) sigaction(SIGQUIT, &sa, NULL);
                sa.sa_handler = SIG_DFL;
                sa.sa_flags = 0;
                (void) sigemptyset(&sa.sa_mask);
                (void) sigaction(SIGTERM, &sa, NULL);
                (void) sigaction(SIGHUP, &sa, NULL);
                (void) wait(NULL);
        }
        exit(0);
}