usr/src/usr.bin/chpass/chpass.c

/*-
 * Copyright (c) 1988 The Regents of the University of California.
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1988 The Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)chpass.c    5.17 (Berkeley) 3/3/91";
#endif /* not lint */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/signal.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <fcntl.h>
#include <pwd.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include "chpass.h"
#include "pathnames.h"

char *progname = "chpass";
char *tempname;
uid_t uid;

main(argc, argv)
        int argc;
        char **argv;
{
        extern int optind;
        extern char *optarg;
        register enum { NEWSH, LOADENTRY, EDITENTRY } op;
        register struct passwd *pw;
        struct passwd lpw;
        int ch, pfd, tfd;
        char *arg;

        op = EDITENTRY;
        while ((ch = getopt(argc, argv, "a:s:")) != EOF)
                switch(ch) {
                case 'a':
                        op = LOADENTRY;
                        arg = optarg;
                        break;
                case 's':
                        op = NEWSH;
                        arg = optarg;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        uid = getuid();

        if (op == EDITENTRY || op == NEWSH)
                switch(argc) {
                case 0:
                        if (!(pw = getpwuid(uid))) {
                                (void)fprintf(stderr,
                                    "chpass: unknown user: uid %u\n", uid);
                                exit(1);
                        }
                        break;
                case 1:
                        if (!(pw = getpwnam(*argv))) {
                                (void)fprintf(stderr,
                                    "chpass: unknown user %s.\n", *argv);
                                exit(1);
                        }
                        if (uid && uid != pw->pw_uid)
                                baduser();
                        break;
                default:
                        usage();
                }

        if (op == NEWSH) {
                /* protect p_shell -- it thinks NULL is /bin/sh */
                if (!arg[0])
                        usage();
                if (p_shell(arg, pw, (ENTRY *)NULL))
                        pw_error((char *)NULL, 0, 1);
        }

        if (op == LOADENTRY) {
                if (uid)
                        baduser();
                pw = &lpw;
                if (!pw_scan(arg, pw))
                        exit(1);
        }

        /*
         * The temporary file/file descriptor usage is a little tricky here.
         * 1:   We start off with two fd's, one for the master password
         *      file (used to lock everything), and one for a temporary file.
         * 2:   Display() gets an fp for the temporary file, and copies the
         *      user's information into it.  It then gives the temporary file
         *      to the user and closes the fp, closing the underlying fd.
         * 3:   The user edits the temporary file some number of times.
         * 4:   Verify() gets an fp for the temporary file, and verifies the
         *      contents.  It can't use an fp derived from the step #2 fd,
         *      because the user's editor may have created a new instance of
         *      the file.  Once the file is verified, its contents are stored
         *      in a password structure.  The verify routine closes the fp,
         *      closing the underlying fd.
         * 5:   Delete the temporary file.
         * 6:   Get a new temporary file/fd.  Pw_copy() gets an fp for it
         *      file and copies the master password file into it, replacing
         *      the user record with a new one.  We can't use the first
         *      temporary file for this because it was owned by the user.
         *      Pw_copy() closes its fp, flushing the data and closing the
         *      underlying file descriptor.  We can't close the master
         *      password fp, or we'd lose the lock.
         * 7:   Call pw_mkdb() (which renames the temporary file) and exit.
         *      The exit closes the master passwd fp/fd.
         */
        pw_init();
        pfd = pw_lock();
        tfd = pw_tmp();

        if (op == EDITENTRY) {
                display(tfd, pw);
                edit(pw);
                (void)unlink(tempname);
                tfd = pw_tmp();
        }

        pw_copy(pfd, tfd, pw);

        if (!pw_mkdb())
                pw_error((char *)NULL, 0, 1);
        exit(0);
}

baduser()
{
        (void)fprintf(stderr, "chpass: %s\n", strerror(EACCES));
        exit(1);
}

usage()
{
        (void)fprintf(stderr, "usage: chpass [-a list] [-s shell] [user]\n");
        exit(1);
}