utmp_update.c revision 1.5 1 /* $NetBSD: utmp_update.c,v 1.5 2002/12/18 15:20:47 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2002 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the NetBSD
21 * Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38 #include <sys/cdefs.h>
39
40 __RCSID("$NetBSD: utmp_update.c,v 1.5 2002/12/18 15:20:47 christos Exp $");
41
42 #include <sys/types.h>
43 #include <sys/param.h>
44 #include <sys/stat.h>
45
46 #include <stdio.h>
47 #include <vis.h>
48 #include <err.h>
49 #include <fcntl.h>
50 #include <pwd.h>
51 #include <utmpx.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <unistd.h>
55 #include <paths.h>
56
57 int main(int, char *[]);
58
59 int
60 main(int argc, char *argv[])
61 {
62 struct utmpx *utx;
63 size_t len;
64 struct passwd *pwd;
65 struct stat st;
66 int fd;
67 uid_t euid;
68 char tty[MAXPATHLEN];
69
70 euid = geteuid();
71 if (seteuid(getuid()) == -1)
72 err(1, "seteuid");
73
74 if (argc != 2) {
75 (void)fprintf(stderr, "Usage: %s <vis-utmpx-entry>\n",
76 getprogname());
77 exit(1);
78 }
79
80 len = strlen(argv[1]);
81
82 if (len > sizeof(*utx) * 4 + 1 || len < sizeof(*utx))
83 errx(1, "Bad argument");
84
85 if ((utx = malloc(len)) == NULL)
86 err(1, NULL);
87
88 if (strunvis((char *)utx, argv[1]) != sizeof(*utx))
89 errx(1, "Decoding error");
90
91 switch (utx->ut_type) {
92 case USER_PROCESS:
93 case DEAD_PROCESS:
94 break;
95 default:
96 errx(1, "Invalid utmpx type %d", (int)utx->ut_type);
97 }
98
99 if ((pwd = getpwuid(getuid())) == NULL)
100 errx(1, "User %lu does not exist in password database",
101 (long)getuid());
102
103 if (strcmp(pwd->pw_name, utx->ut_name) != 0)
104 errx(1, "Current user `%s' does not match `%s' in utmpx entry",
105 pwd->pw_name, utx->ut_name);
106
107 (void)snprintf(tty, sizeof(tty), "%s%s", _PATH_DEV, utx->ut_line);
108 fd = open(tty, O_RDONLY, 0);
109 if (fd == -1)
110 err(1, "Cannot open `%s'", tty);
111 if (fstat(fd, &st) == -1)
112 err(1, "Cannot stat `%s'", tty);
113 if (st.st_uid != getuid())
114 errx(1, "%s: Is not owned by you", tty);
115 if (!isatty(fd))
116 errx(1, "%s: Not a tty device", tty);
117 (void)close(fd);
118 if (access(tty, W_OK|R_OK) == -1)
119 err(1, "%s", tty);
120
121 (void)seteuid(euid);
122 if (pututxline(utx) == NULL)
123 err(1, "Cannot update utmp entry");
124
125 return 0;
126 }
127