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/*

 * Copyright (c) 2009, Kohsuke Ohtani

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the author nor the names of any co-contibutors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

/*

 * lock.c - terminal lock utility.

 *

 * Required capabilities:

 *      CAP_USRFILES

 */

#include <sys/stat.h>

#include <sys/fcntl.h>

#include <unistd.h>

#include <ctype.h>

#include <err.h>

#include <string.h>

#include <stdlib.h>

#include <errno.h>

#include <stdio.h>

#include <paths.h>

static void usage(void);

static void setpass(void);

int

main(int argc, char *argv[])

{

        char passcode[PASSWORD_LEN + 1];

        FILE *fp;

        int update = 0;

        char *p;

        if (argc == 2) {

                if (!strcmp(argv[1], "-u"))

                        update = 1;

                else

                        usage();

        }

        /*

         * Load current passcode.

         */

        if ((fp = fopen(_PATH_PASSWD, "r")) == NULL) {

                printf("Passcode is not set.\n");

                setpass();

        }

        if (((p = fgets(passcode, sizeof(passcode), fp)) == NULL) ||

            (strlen(passcode) != 4)) {

                printf("Invalid passcode is set.\n");

                fclose(fp);

                setpass();

        }

        fclose(fp);

        if (update) {

                /*

                 * Update current passcode.

                 */

                if (strcmp(getpass("Old passcode:"), passcode)) {

                        printf("Mismatch.\n");

                        exit(0);

                }

                setpass();

        }

        /*

         * Lock keyboard until correct passcode input.

         */

        signal(SIGQUIT, SIG_IGN);

        signal(SIGINT, SIG_IGN);

        signal(SIGTSTP, SIG_IGN);

        printf("\33[2J");        /* clear screen */

        printf("Device is locked.\n");

        for (;;) {

                if (!strcmp(getpass("Enter passcode:"), passcode))

                        break;

        }

        exit(0);

}

static void

usage(void)

{

        fputs("usage: lock [-u]\n", stderr);

        exit(1);

        /* NOTREACHED */

}

/*

 * We don't need to encrypt passcode file because it is stored

 * secure area in the file system.

 */

static void

setpass(void)

{

        FILE *fp;

        char *p, *t;

        char buf[PASSWORD_LEN + 1];

        for (buf[0] = '\0';;) {

                p = getpass("New passcode:");

                if (!*p) {

                        printf("Passcode unchanged.\n");

                        exit(0);

                }

                for (t = p; *t && isdigit(*t); ++t);

                if (strlen(p) != 4 || *t) {

                        printf("Please enter 4 digit number for passcode.\n");

                        continue;

                }

                strlcpy(buf, p, sizeof(buf));

                if (!strcmp(buf, getpass("Retype new passcode:")))

                        break;

                printf("Mismatch; try again, EOF to quit.\n");

        }

        if ((fp = fopen(_PATH_PASSWD, "w+")) == NULL) {

                err(1, NULL);

                exit(0);

        }

        fputs(buf, fp);

        fclose(fp);

        exit(0);

}