xref: /freebsd/usr.sbin/chown/chown.c (revision 7899f917b1c0ea178f1d2be0cfb452086d079d23)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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/param.h>
33 #include <sys/stat.h>
34 
35 #include <err.h>
36 #include <errno.h>
37 #include <fcntl.h>
38 #include <fts.h>
39 #include <grp.h>
40 #include <libgen.h>
41 #include <pwd.h>
42 #include <signal.h>
43 #include <stddef.h>
44 #include <stdint.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <unistd.h>
49 
50 static void	a_gid(const char *);
51 static void	a_uid(const char *);
52 static void	chownerr(const char *);
53 static uid_t	id(const char *, const char *);
54 static void	usage(void);
55 static void	print_info(const FTSENT *, int);
56 
57 static uid_t uid;
58 static gid_t gid;
59 static int ischown;
60 static const char *gname;
61 static volatile sig_atomic_t siginfo;
62 
63 static void
64 siginfo_handler(int sig __unused)
65 {
66 
67 	siginfo = 1;
68 }
69 
70 int
71 main(int argc, char **argv)
72 {
73 	FTS *ftsp;
74 	FTSENT *p;
75 	int Hflag, Lflag, Rflag, fflag, hflag, vflag, xflag;
76 	int ch, fts_options, rval;
77 	char *cp;
78 
79 	ischown = (strcmp(basename(argv[0]), "chown") == 0);
80 
81 	Hflag = Lflag = Rflag = fflag = hflag = vflag = xflag = 0;
82 	while ((ch = getopt(argc, argv, "HLPRfhvx")) != -1)
83 		switch (ch) {
84 		case 'H':
85 			Hflag = 1;
86 			Lflag = 0;
87 			break;
88 		case 'L':
89 			Lflag = 1;
90 			Hflag = 0;
91 			break;
92 		case 'P':
93 			Hflag = Lflag = 0;
94 			break;
95 		case 'R':
96 			Rflag = 1;
97 			break;
98 		case 'f':
99 			fflag = 1;
100 			break;
101 		case 'h':
102 			hflag = 1;
103 			break;
104 		case 'v':
105 			vflag++;
106 			break;
107 		case 'x':
108 			xflag = 1;
109 			break;
110 		case '?':
111 		default:
112 			usage();
113 		}
114 	argv += optind;
115 	argc -= optind;
116 
117 	if (argc < 2)
118 		usage();
119 
120 	(void)signal(SIGINFO, siginfo_handler);
121 
122 	if (Rflag) {
123 		if (hflag && (Hflag || Lflag))
124 			errx(1, "the -R%c and -h options may not be "
125 			    "specified together", Hflag ? 'H' : 'L');
126 		if (Lflag) {
127 			fts_options = FTS_LOGICAL;
128 		} else {
129 			fts_options = FTS_PHYSICAL;
130 
131 			if (Hflag) {
132 				fts_options |= FTS_COMFOLLOW;
133 			}
134 		}
135 	} else if (hflag) {
136 		fts_options = FTS_PHYSICAL;
137 	} else {
138 		fts_options = FTS_LOGICAL;
139 	}
140 
141 	if (xflag)
142 		fts_options |= FTS_XDEV;
143 
144 	uid = (uid_t)-1;
145 	gid = (gid_t)-1;
146 	if (ischown) {
147 		if ((cp = strchr(*argv, ':')) != NULL) {
148 			*cp++ = '\0';
149 			a_gid(cp);
150 		}
151 #ifdef SUPPORT_DOT
152 		else if ((cp = strchr(*argv, '.')) != NULL) {
153 			warnx("separation of user and group with a period is deprecated");
154 			*cp++ = '\0';
155 			a_gid(cp);
156 		}
157 #endif
158 		a_uid(*argv);
159 	} else
160 		a_gid(*argv);
161 
162 	if ((ftsp = fts_open(++argv, fts_options, NULL)) == NULL)
163 		err(1, NULL);
164 
165 	for (rval = 0; errno = 0, (p = fts_read(ftsp)) != NULL;) {
166 		int atflag;
167 
168 		if ((fts_options & FTS_LOGICAL) ||
169 		    ((fts_options & FTS_COMFOLLOW) &&
170 		    p->fts_level == FTS_ROOTLEVEL))
171 			atflag = 0;
172 		else
173 			atflag = AT_SYMLINK_NOFOLLOW;
174 
175 		switch (p->fts_info) {
176 		case FTS_D:			/* Change it at FTS_DP. */
177 			if (!Rflag)
178 				fts_set(ftsp, p, FTS_SKIP);
179 			continue;
180 		case FTS_DNR:			/* Warn, chown. */
181 			warnx("%s: %s", p->fts_path, strerror(p->fts_errno));
182 			rval = 1;
183 			break;
184 		case FTS_ERR:			/* Warn, continue. */
185 		case FTS_NS:
186 			warnx("%s: %s", p->fts_path, strerror(p->fts_errno));
187 			rval = 1;
188 			continue;
189 		default:
190 			break;
191 		}
192 		if (siginfo) {
193 			print_info(p, 2);
194 			siginfo = 0;
195 		}
196 		if ((uid == (uid_t)-1 || uid == p->fts_statp->st_uid) &&
197 		    (gid == (gid_t)-1 || gid == p->fts_statp->st_gid))
198 			continue;
199 		if (fchownat(AT_FDCWD, p->fts_accpath, uid, gid, atflag)
200 		    == -1 && !fflag) {
201 			chownerr(p->fts_path);
202 			rval = 1;
203 		} else if (vflag)
204 			print_info(p, vflag);
205 	}
206 	if (errno)
207 		err(1, "fts_read");
208 	exit(rval);
209 }
210 
211 static void
212 a_gid(const char *s)
213 {
214 	struct group *gr;
215 
216 	if (*s == '\0')			/* Argument was "uid[:.]". */
217 		return;
218 	gname = s;
219 	gid = ((gr = getgrnam(s)) != NULL) ? gr->gr_gid : id(s, "group");
220 }
221 
222 static void
223 a_uid(const char *s)
224 {
225 	struct passwd *pw;
226 
227 	if (*s == '\0')			/* Argument was "[:.]gid". */
228 		return;
229 	uid = ((pw = getpwnam(s)) != NULL) ? pw->pw_uid : id(s, "user");
230 }
231 
232 static uid_t
233 id(const char *name, const char *type)
234 {
235 	unsigned long val;
236 	char *ep;
237 
238 	errno = 0;
239 	val = strtoul(name, &ep, 10);
240 	_Static_assert(UID_MAX >= GID_MAX, "UID MAX less than GID MAX");
241 	if (errno || *ep != '\0' || val > UID_MAX)
242 		errx(1, "%s: illegal %s name", name, type);
243 	return (val);
244 }
245 
246 static void
247 chownerr(const char *file)
248 {
249 	static uid_t euid = -1;
250 	static int ngroups = -1;
251 	static long ngroups_max;
252 	gid_t *groups;
253 
254 	/* Check for chown without being root. */
255 	if (errno != EPERM || (uid != (uid_t)-1 &&
256 	    euid == (uid_t)-1 && (euid = geteuid()) != 0)) {
257 		warn("%s", file);
258 		return;
259 	}
260 
261 	/* Check group membership; kernel just returns EPERM. */
262 	if (gid != (gid_t)-1 && ngroups == -1 &&
263 	    euid == (uid_t)-1 && (euid = geteuid()) != 0) {
264 		ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
265 		if ((groups = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
266 			err(1, "malloc");
267 		ngroups = getgroups(ngroups_max, groups);
268 		while (--ngroups >= 0 && gid != groups[ngroups]);
269 		free(groups);
270 		if (ngroups < 0) {
271 			warnx("you are not a member of group %s", gname);
272 			return;
273 		}
274 	}
275 	warn("%s", file);
276 }
277 
278 static void
279 usage(void)
280 {
281 
282 	if (ischown)
283 		(void)fprintf(stderr, "%s\n%s\n",
284 		    "usage: chown [-fhvx] [-R [-H | -L | -P]] owner[:group]"
285 		    " file ...",
286 		    "       chown [-fhvx] [-R [-H | -L | -P]] :group file ...");
287 	else
288 		(void)fprintf(stderr, "%s\n",
289 		    "usage: chgrp [-fhvx] [-R [-H | -L | -P]] group file ...");
290 	exit(1);
291 }
292 
293 static void
294 print_info(const FTSENT *p, int vflag)
295 {
296 
297 	printf("%s", p->fts_path);
298 	if (vflag > 1) {
299 		if (ischown) {
300 			printf(": %ju:%ju -> %ju:%ju",
301 			    (uintmax_t)p->fts_statp->st_uid,
302 			    (uintmax_t)p->fts_statp->st_gid,
303 			    (uid == (uid_t)-1) ?
304 			    (uintmax_t)p->fts_statp->st_uid : (uintmax_t)uid,
305 			    (gid == (gid_t)-1) ?
306 			    (uintmax_t)p->fts_statp->st_gid : (uintmax_t)gid);
307 		} else {
308 			printf(": %ju -> %ju", (uintmax_t)p->fts_statp->st_gid,
309 			    (gid == (gid_t)-1) ?
310 			    (uintmax_t)p->fts_statp->st_gid : (uintmax_t)gid);
311 		}
312 	}
313 	printf("\n");
314 }
315