Merge commit 'b1e7e97d3b60469b243b3b2e22c7d8cbd11c7c90'

[unleashed.git] / usr / src / cmd / consadm / consadm.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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include "utils.h"
#include <locale.h>
#include <poll.h>
#include <setjmp.h>
#include <signal.h>
#include <strings.h>
#include <stropts.h>
#include <syslog.h>
#include <sys/sysmsg_impl.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/systeminfo.h>
#include <sys/termios.h>
#include <sys/types.h>

#define CONSADM                 "/usr/sbin/consadm"
#define CONSADMD                "/usr/sbin/consadmd"
#define CONSADMLOCK             "/tmp/CoNsAdM.lck"
#define CONSDAEMON              "consadmd"
#define MSGLOG                  "/dev/msglog"
#define CONSOLE                 "/dev/console"
#define WSCONS                  "/dev/wscons"
#define CONSCONFIG              "/etc/consadm.conf"
#define SETCONSOLEPID           "/etc/consadm.pid"

#define CONFIG                  0
#define UNCONFIG                1
#define COMMENT                 '#'
#define NEWLINE                 '\n'
#define SPACE                   ' '
#define TAB                     '       '

#define E_SUCCESS       0               /* Exit status for success */
#define E_ERROR         1               /* Exit status for error */
#define E_USAGE         2               /* Exit status for usage error */
#define E_NO_CARRIER    3               /* Exit status for no carrier */

/* useful data structures for lock function */
static struct flock fl;
#define LOCK_EX F_WRLCK

static char usage[] =
        "Usage: \n"
        "\tconsadm [ -p ] [ -a device ... ]\n"
        "\tconsadm [ -p ] [ -d device ... ]\n"
        "\tconsadm [ -p ]\n";

/* data structures ... */
static char conshdr[] =
        "#\n# consadm.conf\n#"
        "# Configuration parameters for console message redirection.\n"
        "# Do NOT edit this file by hand -- use consadm(1m) instead.\n"
        "#\n";
const char *pname;              /* program name */
static sigjmp_buf deadline;

/* command line arguments */
static int display;
static int persist;
static int addflag;
static int deleteflag;

/* function headers */
static void setaux(char *);
static void unsetaux(char *);
static void getconsole(void);
static boolean_t has_carrier(int fd);
static boolean_t modem_support(int fd);
static void setfallback(char *argv[]);
static void removefallback(void);
static void fallbackdaemon(void);
static void persistlist(void);
static int verifyarg(char *, int);
static int safeopen(char *);
static void catch_term(void);
static void catch_alarm(void);
static void catch_hup(void);
static void cleanup_on_exit(void);
static void addtolist(char *);
static void removefromlist(char *);
static int pathcmp(char *, char *);
static int lckfunc(int, int);
typedef void (*sig_handler_t)();
static int getlock(void);

/*
 * In main, return codes carry the following meaning:
 * 0 - successful
 * 1 - error during the command execution
 */

int
main(int argc, char *argv[])
{
        int     index;
        struct  sigaction sa;
        int     c;
        char    *p = strrchr(argv[0], '/');

        if (p == NULL)
                p = argv[0];
        else
                p++;

        pname = p;

        (void) setlocale(LC_ALL, "");
#if     !defined(TEXT_DOMAIN)   /* Should be defined by cc -D */
#define TEXT_DOMAIN "SYS_TEST"  /* Use this only if it weren't */
#endif
        (void) textdomain(TEXT_DOMAIN);

        if (getuid() != 0)
                die(gettext("must be root to run this program\n"));

        /*
         * Handle normal termination signals that may be received.
         */
        sa.sa_handler = SIG_IGN;
        sa.sa_flags = 0;
        (void) sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGHUP, &sa, NULL);
        (void) sigaction(SIGINT, &sa, NULL);
        (void) sigaction(SIGQUIT, &sa, NULL);
        (void) sigaction(SIGTERM, &sa, NULL);

        /*
         * To make sure persistent state gets removed.
         */
        sa.sa_handler = cleanup_on_exit;
        sa.sa_flags = 0;
        (void) sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGSEGV, &sa, NULL);
        (void) sigaction(SIGILL, &sa, NULL);
        (void) sigaction(SIGABRT, &sa, NULL);
        (void) sigaction(SIGBUS, &sa, NULL);

        if (strcmp(pname, CONSDAEMON) == 0) {
                fallbackdaemon();
                return (E_SUCCESS);
        }

        if (argc == 1)
                display++;
        else {
                while ((c = getopt(argc, argv, "adp")) != EOF)  {
                        switch (c) {
                        case 'a':
                                addflag++;
                                break;
                        case 'd':
                                deleteflag++;
                                break;
                        case 'p':
                                persist++;
                                break;
                        default:
                                (void) fprintf(stderr, gettext(usage));
                                exit(E_USAGE);
                                /*NOTREACHED*/
                        }
                }
        }

        if (display) {
                getconsole();
                return (E_SUCCESS);
        }
        if (addflag && deleteflag) {
                (void) fprintf(stderr, gettext(usage));
                return (E_ERROR);
        }
        if (addflag) {
                if (optind == argc) {
                        (void) fprintf(stderr, gettext(usage));
                        return (E_ERROR);
                }
                /* separately check every device path specified */
                for (index = optind; index < argc; index++) {
                        if (verifyarg(argv[index], addflag))
                                return (E_ERROR);
                }

                for (index = optind; index < argc; index++) {
                        setaux(argv[index]);
                        if (persist)
                                addtolist(argv[index]);
                }

                /*
                 * start/restart daemon based on the auxilary
                 * consoles at this time.
                 */
                setfallback(argv);
                return (E_SUCCESS);
        } else if (deleteflag) {
                if (optind == argc) {
                        (void) fprintf(stderr, gettext(usage));
                        return (E_ERROR);
                }
                /* separately check every device path specified */
                for (index = optind; index < argc; index++) {
                        if (verifyarg(argv[index], 0))
                                return (E_ERROR);
                }

                for (index = optind; index < argc; index++) {
                        unsetaux(argv[index]);
                        if (persist && deleteflag)
                                removefromlist(argv[index]);
                }

                /*
                 * kill off daemon and restart with
                 * new list of auxiliary consoles
                 */
                setfallback(argv);
                return (E_SUCCESS);
        } else if (persist) {
                if (optind < argc) {
                        (void) fprintf(stderr, gettext(usage));
                        return (E_ERROR);
                }

                persistlist();
                return (E_SUCCESS);
        } else {
                (void) fprintf(stderr, gettext(usage));
                return (E_ERROR);
        }
} /* main */

/* for daemon to handle termination from user command */
static void
catch_term()
{
        exit(E_SUCCESS);
}

/* handle lack of carrier on open */
static void
catch_alarm()
{
        siglongjmp(deadline, 1);
}

/* caught a sighup */
static void
catch_hup()
{
        /*
         * ttymon sends sighup to consadmd because it has the serial
         * port open.  We catch the signal here, but process it
         * within fallbackdaemon().  We ignore the signal if the
         * errno returned was EINTR.
         */
}

/* Remove persistent state on receiving signal. */
static void
cleanup_on_exit()
{
        (void) unlink(CONSADMLOCK);
        exit(E_ERROR);
}

/*
 * send ioctl to /dev/sysmsg to route msgs of the device specified.
 */
static void
setaux(char *dev)
{
        int     fd;

        if ((fd = safeopen(SYSMSG)) < 0)
                die(gettext("%s is missing or not a valid device\n"), SYSMSG);

        if (ioctl(fd, CIOCSETCONSOLE, dev) != 0) {
                /*
                 * Let setting duplicate device be warning, consadm
                 * must proceed to set persistence if requested.
                 */
                if (errno == EBUSY)
                        die(gettext("%s is already the default console\n"),
                            dev);
                else if (errno != EEXIST)
                        die(gettext("cannot get table entry"));
        }
        syslog(LOG_WARNING, "%s: Added auxiliary device %s", CONSADM, dev);

        (void) close(fd);
}

/*
 * Send ioctl to device specified and
 * Remove the entry from the list of auxiliary devices.
 */
static void
unsetaux(char *dev)
{
        int     fd;

        if ((fd = safeopen(SYSMSG)) < 0)
                die(gettext("%s is missing or not a valid device\n"), SYSMSG);

        if (ioctl(fd, CIOCRMCONSOLE, dev) != 0) {
                if (errno == EBUSY)
                        die(gettext("cannot unset the default console\n"));
        } else
                syslog(LOG_WARNING, "%s: Removed auxiliary device %s",
                    CONSADM, dev);
        (void) close(fd);
}

static int
getlock(void)
{
        int lckfd;

        if ((lckfd = open(CONSADMLOCK, O_CREAT | O_EXCL | O_WRONLY,
            S_IRUSR | S_IWUSR)) < 0) {
                if (errno == EEXIST)
                        die(gettext("currently busy, try again later.\n"));
                else
                        die(gettext("cannot open %s"), CONSADMLOCK);
        }
        if (lckfunc(lckfd, LOCK_EX) == -1) {
                (void) close(lckfd);
                (void) unlink(CONSADMLOCK);
                die(gettext("fcntl operation failed"));
        }
        return (lckfd);
}

static void
addtolist(char *dev)
{
        int     lckfd, fd;
        FILE    *fp, *nfp;
        char    newfile[MAXPATHLEN];
        char    buf[MAXPATHLEN];
        int     len;
        boolean_t       found = B_FALSE;

        /* update file of devices configured to get console msgs. */

        lckfd = getlock();

        /* Open new file */
        (void) snprintf(newfile, sizeof (newfile), "%s%d",
            CONSCONFIG, (int)getpid());
        if (((fd = creat(newfile, 0644)) < 0) ||
            ((nfp = fdopen(fd, "w")) == NULL)) {
                (void) close(lckfd);
                (void) unlink(CONSADMLOCK);
                die(gettext("could not create new %s file"), CONSCONFIG);
        }

        /* Add header to new file */
        (void) fprintf(nfp, "%s", conshdr);

        /* Check that the file doesn't already exist */
        if ((fp = fopen(CONSCONFIG, "r")) != NULL) {
                while (fgets(buf, MAXPATHLEN, fp) != NULL) {
                        if (buf[0] == COMMENT || buf[0] == NEWLINE ||
                            buf[0] == SPACE || buf[0] == TAB)
                                continue;
                        len = strlen(buf);
                        buf[len - 1] = '\0'; /* Clear carriage return */
                        if (pathcmp(dev, buf) == 0) {
                                /* they match so use name passed in. */
                                (void) fprintf(nfp, "%s\n", dev);
                                found = B_TRUE;
                        } else
                                (void) fprintf(nfp, "%s\n", buf);
                }
        }
        /* User specified persistent settings */
        if (found == B_FALSE)
                (void) fprintf(nfp, "%s\n", dev);

        (void) fclose(fp);
        (void) fclose(nfp);
        (void) rename(newfile, CONSCONFIG);
        (void) close(lckfd);
        (void) unlink(CONSADMLOCK);
}

/* The list in CONSCONFIG gives the persistence capability in the proto */
static void
removefromlist(char *dev)
{
        int     lckfd;
        FILE    *fp, *nfp;
        char    newfile[MAXPATHLEN + 1];
        char    len;
        char    value[MAXPATHLEN + 1];
        boolean_t       newcontents = B_FALSE;

        /* update file of devices configured to get console msgs. */

        lckfd = getlock();

        if ((fp = fopen(CONSCONFIG, "r")) == NULL) {
                (void) close(lckfd);
                (void) unlink(CONSADMLOCK);
                return;
        }

        /* Open new file */
        (void) snprintf(newfile, sizeof (newfile), "%s%d",
            CONSCONFIG, (int)getpid());
        if ((nfp = fopen(newfile, "w")) == NULL) {
                (void) close(lckfd);
                (void) unlink(CONSADMLOCK);
                die(gettext("cannot create new %s file"), CONSCONFIG);
        }

        /* Add header to new file */
        (void) fprintf(nfp, "%s", conshdr);

        /*
         * Check whether the path duplicates what is already in the
         * file.
         */
        while (fgets(value, MAXPATHLEN, fp) != NULL) {
                /* skip comments */
                if (value[0] == COMMENT || value[0] == NEWLINE ||
                    value[0] == SPACE || value[0] == TAB)
                        continue;
                len = strlen(value);
                value[len - 1] = '\0'; /* Clear carriage return */
                if (pathcmp(dev, value) == 0) {
                        /* they match so don't write it */
                        continue;
                }
                (void) fprintf(nfp, "%s\n", value);
                newcontents = B_TRUE;
        }
        (void) fclose(fp);
        (void) fclose(nfp);
        /* Remove the file if there aren't any auxiliary consoles */
        if (newcontents)
                (void) rename(newfile, CONSCONFIG);
        else {
                (void) unlink(CONSCONFIG);
                (void) unlink(newfile);
        }
        (void) close(lckfd);
        (void) unlink(CONSADMLOCK);
}

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

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

        if (stat(adev, &st1) != 0 || !S_ISCHR(st1.st_mode))
                die(gettext("invalid device %s\n"), adev);

        if (stat(bdev, &st2) != 0 || !S_ISCHR(st2.st_mode))
                die(gettext("invalid device %s\n"), bdev);

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

        return (1);
}

/*
 * Display configured consoles.
 */
static void
getconsole(void)
{
        int     fd;
        int     bufsize = 0;            /* size of device cache */
        char    *infop, *ptr, *p;       /* info structure for ioctl's */

        if ((fd = safeopen(SYSMSG)) < 0)
                die(gettext("%s is missing or not a valid device\n"), SYSMSG);

        if ((bufsize = ioctl(fd, CIOCGETCONSOLE, NULL)) < 0)
                die(gettext("cannot get table entry\n"));
        if (bufsize == 0)
                return;

        if ((infop = calloc(bufsize, sizeof (char))) == NULL)
                die(gettext("cannot allocate buffer"));

        if (ioctl(fd, CIOCGETCONSOLE, infop) < 0)
                die(gettext("cannot get table entry\n"));

        ptr = infop;
        while (ptr != NULL) {
                p = strchr(ptr, ' ');
                if (p == NULL) {
                        (void) printf("%s\n", ptr);
                        break;
                }
                *p++ = '\0';
                (void) printf("%s\n", ptr);
                ptr = p;
        }
        (void) close(fd);
}

/*
 * It is supposed that if the device supports TIOCMGET then it
 * might be a serial device.
 */
static boolean_t
modem_support(int fd)
{
        int     modem_state;

        if (ioctl(fd, TIOCMGET, &modem_state) == 0)
                return (B_TRUE);
        else
                return (B_FALSE);
}

static boolean_t
has_carrier(int fd)
{
        int     modem_state;

        if (ioctl(fd, TIOCMGET, &modem_state) == 0)
                return ((modem_state & TIOCM_CAR) != 0);
        else {
                return (B_FALSE);
        }
}

static void
setfallback(char *argv[])
{
        pid_t   pid;
        FILE    *fp;
        char    *cmd = CONSADMD;
        int     lckfd, fd;

        lckfd = getlock();

        /*
         * kill off any existing daemon
         * remove /etc/consadm.pid
         */
        removefallback();

        /* kick off a daemon */
        if ((pid = fork()) == (pid_t)0) {
                /* always fallback to /dev/console */
                argv[0] = cmd;
                argv[1] = NULL;
                (void) close(0);
                (void) close(1);
                (void) close(2);
                (void) close(lckfd);
                if ((fd = open(MSGLOG, O_RDWR)) < 0)
                        die(gettext("cannot open %s"), MSGLOG);
                (void) dup2(fd, 1);
                (void) dup2(fd, 2);
                (void) execv(cmd, argv);
                exit(E_SUCCESS);
        } else if (pid == -1)
                die(gettext("%s not started"), CONSADMD);

        if ((fp = fopen(SETCONSOLEPID, "w")) == NULL)
                die(gettext("cannot open %s"), SETCONSOLEPID);
        /* write daemon pid to file */
        (void) fprintf(fp, "%d\n", (int)pid);
        (void) fclose(fp);
        (void) close(lckfd);
        (void) unlink(CONSADMLOCK);
}

/*
 * Remove the daemon that would have implemented the automatic
 * fallback in event of carrier loss on the serial console.
 */
static void
removefallback(void)
{
        FILE    *fp;
        int     pid;

        if ((fp = fopen(SETCONSOLEPID, "r+")) == NULL)
                /* file doesn't exist, so no work to do */
                return;

        if (fscanf(fp, "%d\n", &pid) <= 0) {
                (void) fclose(fp);
                (void) unlink(SETCONSOLEPID);
                return;
        }

        /*
         * Don't shoot ourselves in the foot by killing init,
         * sched, pageout, or fsflush.
         */
        if (pid == 0 || pid == 1 || pid == 2 || pid == 3) {
                (void) unlink(SETCONSOLEPID);
                return;
        }
        /*
         * kill off the existing daemon listed in
         * /etc/consadm.pid
         */
        (void) kill((pid_t)pid, SIGTERM);

        (void) fclose(fp);
        (void) unlink(SETCONSOLEPID);
}

/*
 * Assume we always fall back to /dev/console.
 * parameter passed in will always be the auxiliary device.
 * The daemon will not start after the last device has been removed.
 */
static void
fallbackdaemon(void)
{
        int     fd, sysmfd, ret = 0;
        char    **devpaths;
        pollfd_t        *fds;
        nfds_t  nfds = 0;
        int     index;
        int     pollagain;
        struct  sigaction sa;
        int     bufsize = 0;            /* length of device cache paths */
        int     cachesize = 0;          /* size of device cache */
        char    *infop, *ptr, *p;       /* info structure for ioctl's */

        /*
         * catch SIGTERM cause it might be coming from user via consadm
         */
        sa.sa_handler = catch_term;
        sa.sa_flags = 0;
        (void) sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGTERM, &sa, NULL);

        /*
         * catch SIGHUP cause it might be coming from a disconnect
         */
        sa.sa_handler = catch_hup;
        sa.sa_flags = 0;
        (void) sigemptyset(&sa.sa_mask);
        (void) sigaction(SIGHUP, &sa, NULL);

        if ((sysmfd = safeopen(SYSMSG)) < 0)
                die(gettext("%s is missing or not a valid device\n"), SYSMSG);

        if ((bufsize = ioctl(sysmfd, CIOCGETCONSOLE, NULL)) < 0)
                die(gettext("cannot get table entry\n"));
        if (bufsize == 0)
                return;

        if ((infop = calloc(bufsize, sizeof (char))) == NULL)
                die(gettext("cannot allocate buffer"));

        if (ioctl(sysmfd, CIOCGETCONSOLE, infop) < 0)
                die(gettext("cannot get table entry\n"));

        ptr = infop;
        while (ptr != NULL) {
                p = strchr(ptr, ' ');
                if (p == NULL) {
                        cachesize++;
                        break;
                }
                p++;
                cachesize++;
                ptr = p;
        }

        if ((fds = calloc(cachesize, sizeof (struct pollfd))) == NULL)
                die(gettext("cannot allocate buffer"));

        if ((devpaths = calloc(cachesize, sizeof (char *))) == NULL)
                die(gettext("cannot allocate buffer"));

        ptr = infop;
        while (ptr != NULL) {
                p = strchr(ptr, ' ');
                if (p == NULL) {
                        if ((fd = safeopen(ptr)) < 0) {
                                warn(gettext("cannot open %s, continuing"),
                                    ptr);
                                break;
                        }
                        if (!has_carrier(fd)) {
                                (void) close(fd);
                                warn(gettext(
                    "no carrier on %s, device will not be monitored.\n"),
                                    ptr);
                                break;
                        } else {
                                fds[nfds].fd = fd;
                                fds[nfds].events = 0;

                                if ((devpaths[nfds] =
                                    malloc(strlen(ptr) + 1)) == NULL)
                                        die(gettext("cannot allocate buffer"));

                                (void) strcpy(devpaths[nfds], ptr);
                                nfds++;
                                if (nfds >= cachesize)
                                        break;
                        }
                        break;
                }
                *p++ = '\0';

                if ((fd = safeopen(ptr)) < 0) {
                        warn(gettext("cannot open %s, continuing"), ptr);
                        ptr = p;
                        continue;
                }
                if (!has_carrier(fd)) {
                        (void) close(fd);
                        warn(gettext(
                    "no carrier on %s, device will not be monitored.\n"),
                            ptr);
                        ptr = p;
                        continue;
                } else {
                        fds[nfds].fd = fd;
                        fds[nfds].events = 0;

                        if ((devpaths[nfds] = malloc(strlen(ptr) + 1)) == NULL)
                                die(gettext("cannot allocate buffer"));

                        (void) strcpy(devpaths[nfds], ptr);
                        nfds++;
                        if (nfds >= cachesize)
                                break;
                }
                ptr = p;
        }
        (void) close(sysmfd);

        /* no point polling if no devices with carrier */
        if (nfds == 0)
                return;

        for (;;) {
                /* daemon sleeps waiting for a hangup on the console */
                ret = poll(fds, nfds, INFTIM);
                if (ret == -1) {
                        /* Check if ttymon is trying to get rid of us */
                        if (errno == EINTR)
                                continue;
                        warn(gettext("cannot poll device"));
                        return;
                } else if (ret == 0) {
                        warn(gettext("timeout (%d milleseconds) occured\n"),
                            INFTIM);
                        return;
                } else {
                        /* Go through poll list looking for events. */
                        for (index = 0; index < nfds; index++) {
                                /* expected result */
                                if ((fds[index].revents & POLLHUP) ==
                                    POLLHUP) {
                                        /*
                                         * unsetaux console.  Take out of list
                                         * of current auxiliary consoles.
                                         */
                                        unsetaux((char *)devpaths[index]);
                                        warn(gettext(
                                    "lost carrier, unsetting console %s\n"),
                                            devpaths[index]);
                                        syslog(LOG_WARNING,
                            "%s: lost carrier, unsetting auxiliary device %s",
                                            CONSADM, devpaths[index]);
                                        free(devpaths[index]);
                                        devpaths[index] = NULL;
                                        (void) close(fds[index].fd);
                                        fds[index].fd = -1;
                                        fds[index].revents = 0;
                                        continue;
                                }
                                if ((fds[index].revents & POLLERR) ==
                                    POLLERR) {
                                        warn(gettext("poll error\n"));
                                        continue;
                                } else if (fds[index].revents != 0) {
                                        warn(gettext(
                                            "unexpected poll result 0x%x\n"),
                                            fds[index].revents);
                                        continue;
                                }
                        }
                        /* check whether any left to poll */
                        pollagain = B_FALSE;
                        for (index = 0; index < nfds; index++)
                                if (fds[index].fd != -1)
                                        pollagain = B_TRUE;
                        if (pollagain == B_TRUE)
                                continue;
                        else
                                return;
                }
        }
}

static void
persistlist(void)
{
        FILE    *fp;
        char    value[MAXPATHLEN + 1];
        int     lckfd;

        lckfd = getlock();

        if ((fp = fopen(CONSCONFIG, "r")) != NULL) {
                while (fgets(value, MAXPATHLEN, fp) != NULL) {
                        /* skip comments */
                        if (value[0] == COMMENT ||
                            value[0] == NEWLINE ||
                            value[0] == SPACE || value[0] == TAB)
                                continue;
                        (void) fprintf(stdout, "%s", value);
                }
                (void) fclose(fp);
        }
        (void) close(lckfd);
        (void) unlink(CONSADMLOCK);
}

static int
verifyarg(char *dev, int flag)
{
        struct stat     st;
        int     fd;
        int     ret = 0;

        if (dev == NULL) {
                warn(gettext("specify device(s)\n"));
                ret = 1;
                goto err_exit;
        }

        if (dev[0] != '/') {
                warn(gettext("device name must begin with a '/'\n"));
                ret = 1;
                goto err_exit;
        }

        if ((pathcmp(dev, SYSMSG) == 0) ||
            (pathcmp(dev, WSCONS) == 0) ||
            (pathcmp(dev, CONSOLE) == 0)) {
                /* they match */
                warn(gettext("invalid device %s\n"), dev);
                ret = 1;
                goto err_exit;
        }

        if (stat(dev, &st) || ! S_ISCHR(st.st_mode)) {
                warn(gettext("invalid device %s\n"), dev);
                ret = 1;
                goto err_exit;
        }

        /* Delete operation doesn't require this checking */
        if ((fd = safeopen(dev)) < 0) {
                if (flag) {
                        warn(gettext("invalid device %s\n"), dev);
                        ret = 1;
                }
                goto err_exit;
        }
        if (!modem_support(fd)) {
                warn(gettext("invalid device %s\n"), dev);
                (void) close(fd);
                ret = 1;
                goto err_exit;
        }

        /* Only verify carrier if it's an add operation */
        if (flag) {
                if (!has_carrier(fd)) {
                        warn(gettext("failure, no carrier on %s\n"), dev);
                        ret = 1;
                        goto err_exit;
                }
        }
err_exit:
        return (ret);
}

/*
 * Open the pseudo device, but be prepared to catch sigalarm if we block
 * cause there isn't any carrier present.
 */
static int
safeopen(char *devp)
{
        int     fd;
        struct  sigaction sigact;

        sigact.sa_flags = SA_RESETHAND | SA_NODEFER;
        sigact.sa_handler = catch_alarm;
        (void) sigemptyset(&sigact.sa_mask);
        (void) sigaction(SIGALRM, &sigact, NULL);
        if (sigsetjmp(deadline, 1) != 0)
                return (-1);
        (void) alarm(5);
        /* The sysmsg driver sets NONBLOCK and NDELAY, but what the hell */
        if ((fd = open(devp, O_RDWR | O_NOCTTY | O_NONBLOCK | O_NDELAY)) < 0)
                return (-1);
        (void) alarm(0);
        sigact.sa_flags = 0;
        sigact.sa_handler = SIG_DFL;
        (void) sigemptyset(&sigact.sa_mask);
        (void) sigaction(SIGALRM, &sigact, NULL);
        return (fd);
}

static int
lckfunc(int fd, int flag)
{
        fl.l_type = flag;
        return (fcntl(fd, F_SETLKW, &fl));
}