xref: /netbsd-src/usr.bin/chpass/chpass.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: chpass.c,v 1.30 2005/06/02 01:41:38 lukem Exp $	*/
2 
3 /*-
4  * Copyright (c) 1988, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1988, 1993, 1994\n\
35 	The Regents of the University of California.  All rights reserved.\n");
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)chpass.c	8.4 (Berkeley) 4/2/94";
41 #else
42 __RCSID("$NetBSD: chpass.c,v 1.30 2005/06/02 01:41:38 lukem Exp $");
43 #endif
44 #endif /* not lint */
45 
46 #include <sys/param.h>
47 #include <sys/stat.h>
48 #include <sys/time.h>
49 #include <sys/resource.h>
50 
51 #include <ctype.h>
52 #include <err.h>
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <pwd.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60 #include <util.h>
61 
62 #include "chpass.h"
63 #include "pathnames.h"
64 
65 static char tempname[] = "/etc/pw.XXXXXX";
66 uid_t uid;
67 int use_yp;
68 
69 void	(*Pw_error)(const char *, int, int);
70 
71 #ifdef	YP
72 extern	int _yp_check(char **);	/* buried deep inside libc */
73 #endif
74 
75 void	baduser(void);
76 void	cleanup(void);
77 void	usage(void);
78 
79 int
80 main(int argc, char **argv)
81 {
82 	enum { NEWSH, LOADENTRY, EDITENTRY } op;
83 	struct passwd *pw, lpw, old_pw;
84 	int ch, dfd, pfd, tfd;
85 #ifdef YP
86 	int yflag = 0;
87 #endif
88 	char *arg, *username = NULL;
89 
90 #ifdef __GNUC__
91 	pw = NULL;		/* XXX gcc -Wuninitialized */
92 	arg = NULL;
93 #endif
94 #ifdef	YP
95 	use_yp = _yp_check(NULL);
96 #endif
97 
98 	op = EDITENTRY;
99 	while ((ch = getopt(argc, argv, "a:s:ly")) != -1)
100 		switch (ch) {
101 		case 'a':
102 			op = LOADENTRY;
103 			arg = optarg;
104 			break;
105 		case 's':
106 			op = NEWSH;
107 			arg = optarg;
108 			break;
109 		case 'l':
110 			use_yp = 0;
111 			break;
112 		case 'y':
113 #ifdef	YP
114 			if (!use_yp)
115 				errx(1, "YP not in use.");
116 			yflag = 1;
117 #else
118 			errx(1, "YP support not compiled in.");
119 #endif
120 			break;
121 		default:
122 			usage();
123 		}
124 	argc -= optind;
125 	argv += optind;
126 
127 	uid = getuid();
128 	switch (argc) {
129 	case 0:
130 		/* nothing */
131 		break;
132 
133 	case 1:
134 		username = argv[0];
135 		break;
136 
137 	default:
138 		usage();
139 	}
140 
141 #ifdef YP
142 	/*
143 	 * We need to determine if we _really_ want to use YP.
144 	 * If we defaulted to YP (i.e. were not given the -y flag),
145 	 * and the master is not running rpc.yppasswdd, we check
146 	 * to see if the user exists in the local passwd database.
147 	 * If so, we use it, otherwise we error out.
148 	 */
149 	if (use_yp && yflag == 0) {
150 		if (check_yppasswdd()) {
151 			/*
152 			 * We weren't able to contact rpc.yppasswdd.
153 			 * Check to see if we're in the local
154 			 * password database.  If we are, use it.
155 			 */
156 			if (username != NULL)
157 				pw = getpwnam(username);
158 			else
159 				pw = getpwuid(uid);
160 			if (pw != NULL)
161 				use_yp = 0;
162 			else {
163 				warnx("master YP server not running yppasswd"
164 				    " daemon.");
165 				errx(1, "Can't change password.");
166 			}
167 		}
168 	}
169 #endif
170 
171 #ifdef YP
172 	if (use_yp)
173 		Pw_error = yppw_error;
174 	else
175 #endif
176 		Pw_error = pw_error;
177 
178 #ifdef	YP
179 	if (op == LOADENTRY && use_yp)
180 		errx(1, "cannot load entry using YP.\n"
181 		    "\tUse the -l flag to load local.");
182 #endif
183 
184 	if (op == EDITENTRY || op == NEWSH) {
185 		if (username != NULL) {
186 			pw = getpwnam(username);
187 			if (pw == NULL)
188 				errx(1, "unknown user: %s", username);
189 			if (uid && uid != pw->pw_uid)
190 				baduser();
191 		} else {
192 			pw = getpwuid(uid);
193 			if (pw == NULL)
194 				errx(1, "unknown user: uid %u", uid);
195 		}
196 
197 		/* Make a copy for later verification */
198 		old_pw = *pw;
199 		old_pw.pw_gecos = strdup(old_pw.pw_gecos);
200 		if (!old_pw.pw_gecos) {
201 			err(1, "strdup");
202 			/*NOTREACHED*/
203 		}
204 	}
205 
206 	if (op == NEWSH) {
207 		/* protect p_shell -- it thinks NULL is /bin/sh */
208 		if (!arg[0])
209 			usage();
210 		if (p_shell(arg, pw, NULL))
211 			(*Pw_error)(NULL, 0, 1);
212 	}
213 
214 	if (op == LOADENTRY) {
215 		if (uid)
216 			baduser();
217 		pw = &lpw;
218 		if (!pw_scan(arg, pw, NULL))
219 			exit(1);
220 	}
221 
222 	/* Edit the user passwd information if requested. */
223 	if (op == EDITENTRY) {
224 		dfd = mkstemp(tempname);
225 		if (dfd < 0 || fcntl(dfd, F_SETFD, 1) < 0)
226 			(*Pw_error)(tempname, 1, 1);
227 		if (atexit(cleanup)) {
228 			cleanup();
229 			errx(1, "couldn't register cleanup");
230 		}
231 		display(tempname, dfd, pw);
232 		edit(tempname, pw);
233 	}
234 
235 #ifdef	YP
236 	if (use_yp) {
237 		if (pw_yp(pw, uid))
238 			yppw_error((char *)NULL, 0, 1);
239 		else
240 			exit(0);
241 		/* Will not exit from this if. */
242 	}
243 #endif	/* YP */
244 
245 
246 	/*
247 	 * Get the passwd lock file and open the passwd file for
248 	 * reading.
249 	 */
250 	pw_init();
251 	tfd = pw_lock(0);
252 	if (tfd < 0) {
253 		if (errno != EEXIST)
254 			err(1, "%s", _PATH_MASTERPASSWD_LOCK);
255 		warnx("The passwd file is busy, waiting...");
256 		tfd = pw_lock(10);
257 		if (tfd < 0) {
258 			if (errno != EEXIST)
259 				err(1, "%s", _PATH_MASTERPASSWD_LOCK);
260 			errx(1, "The passwd file is still busy, "
261 			     "try again later.");
262 		}
263 	}
264 	if (fcntl(tfd, F_SETFD, 1) < 0)
265 		pw_error(_PATH_MASTERPASSWD_LOCK, 1, 1);
266 
267 	pfd = open(_PATH_MASTERPASSWD, O_RDONLY, 0);
268 	if (pfd < 0 || fcntl(pfd, F_SETFD, 1) < 0)
269 		pw_error(_PATH_MASTERPASSWD, 1, 1);
270 
271 	/* Copy the passwd file to the lock file, updating pw. */
272 	pw_copy(pfd, tfd, pw, (op == LOADENTRY) ? NULL : &old_pw);
273 
274 	/* Now finish the passwd file update. */
275 	if (pw_mkdb(username, 0) < 0)
276 		pw_error(NULL, 0, 1);
277 
278 	exit(0);
279 }
280 
281 void
282 baduser(void)
283 {
284 
285 	errx(1, "%s", strerror(EACCES));
286 }
287 
288 void
289 usage(void)
290 {
291 
292 	(void)fprintf(stderr,
293 	    "usage: %s [-a list] [-s shell] [-l] [user]\n"
294 	    "       %s [-a list] [-s shell] [-y] [user]\n",
295 	    getprogname(), getprogname());
296 	exit(1);
297 }
298 
299 void
300 cleanup(void)
301 {
302 
303 	(void)unlink(tempname);
304 }
305