NetBSD/libexec/utmp_update/utmp_update.c

127 lines
3.8 KiB
C

/* $NetBSD: utmp_update.c,v 1.5 2002/12/18 15:20:47 christos Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas.
*
* 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 NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: utmp_update.c,v 1.5 2002/12/18 15:20:47 christos Exp $");
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <stdio.h>
#include <vis.h>
#include <err.h>
#include <fcntl.h>
#include <pwd.h>
#include <utmpx.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <paths.h>
int main(int, char *[]);
int
main(int argc, char *argv[])
{
struct utmpx *utx;
size_t len;
struct passwd *pwd;
struct stat st;
int fd;
uid_t euid;
char tty[MAXPATHLEN];
euid = geteuid();
if (seteuid(getuid()) == -1)
err(1, "seteuid");
if (argc != 2) {
(void)fprintf(stderr, "Usage: %s <vis-utmpx-entry>\n",
getprogname());
exit(1);
}
len = strlen(argv[1]);
if (len > sizeof(*utx) * 4 + 1 || len < sizeof(*utx))
errx(1, "Bad argument");
if ((utx = malloc(len)) == NULL)
err(1, NULL);
if (strunvis((char *)utx, argv[1]) != sizeof(*utx))
errx(1, "Decoding error");
switch (utx->ut_type) {
case USER_PROCESS:
case DEAD_PROCESS:
break;
default:
errx(1, "Invalid utmpx type %d", (int)utx->ut_type);
}
if ((pwd = getpwuid(getuid())) == NULL)
errx(1, "User %lu does not exist in password database",
(long)getuid());
if (strcmp(pwd->pw_name, utx->ut_name) != 0)
errx(1, "Current user `%s' does not match `%s' in utmpx entry",
pwd->pw_name, utx->ut_name);
(void)snprintf(tty, sizeof(tty), "%s%s", _PATH_DEV, utx->ut_line);
fd = open(tty, O_RDONLY, 0);
if (fd == -1)
err(1, "Cannot open `%s'", tty);
if (fstat(fd, &st) == -1)
err(1, "Cannot stat `%s'", tty);
if (st.st_uid != getuid())
errx(1, "%s: Is not owned by you", tty);
if (!isatty(fd))
errx(1, "%s: Not a tty device", tty);
(void)close(fd);
if (access(tty, W_OK|R_OK) == -1)
err(1, "%s", tty);
(void)seteuid(euid);
if (pututxline(utx) == NULL)
err(1, "Cannot update utmp entry");
return 0;
}