xref: /freebsd/bin/rm/rm.c (revision 6a66acb565dde6d5b0ee52eef2a631fbb09df153)
1 /*-
2  * Copyright (c) 1990, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 static const char copyright[] =
36 "@(#) Copyright (c) 1990, 1993, 1994\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 #if 0
42 static char sccsid[] = "@(#)rm.c	8.5 (Berkeley) 4/18/94";
43 #endif
44 #endif /* not lint */
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
47 
48 #include <sys/stat.h>
49 #include <sys/param.h>
50 #include <sys/mount.h>
51 
52 #include <err.h>
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <fts.h>
56 #include <grp.h>
57 #include <pwd.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <sysexits.h>
62 #include <unistd.h>
63 
64 int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
65 uid_t uid;
66 
67 int	check(char *, char *, struct stat *);
68 void	checkdot(char **);
69 void	rm_file(char **);
70 void	rm_overwrite(char *, struct stat *);
71 void	rm_tree(char **);
72 void	usage(void);
73 
74 /*
75  * rm --
76  *	This rm is different from historic rm's, but is expected to match
77  *	POSIX 1003.2 behavior.  The most visible difference is that -f
78  *	has two specific effects now, ignore non-existent files and force
79  * 	file removal.
80  */
81 int
82 main(int argc, char *argv[])
83 {
84 	int ch, rflag;
85 	char *p;
86 
87 	/*
88 	 * Test for the special case where the utility is called as
89 	 * "unlink", for which the functionality provided is greatly
90 	 * simplified.
91 	 */
92 	if ((p = rindex(argv[0], '/')) == NULL)
93 		p = argv[0];
94 	else
95 		++p;
96 	if (strcmp(p, "unlink") == 0) {
97 		while (getopt(argc, argv, "") != -1)
98 			usage();
99 		argc -= optind;
100 		argv += optind;
101 		if (argc != 1)
102 			usage();
103 		rm_file(&argv[0]);
104 		exit(eval);
105 	}
106 
107 	Pflag = rflag = 0;
108 	while ((ch = getopt(argc, argv, "dfiPRrvW")) != -1)
109 		switch(ch) {
110 		case 'd':
111 			dflag = 1;
112 			break;
113 		case 'f':
114 			fflag = 1;
115 			iflag = 0;
116 			break;
117 		case 'i':
118 			fflag = 0;
119 			iflag = 1;
120 			break;
121 		case 'P':
122 			Pflag = 1;
123 			break;
124 		case 'R':
125 		case 'r':			/* Compatibility. */
126 			rflag = 1;
127 			break;
128 		case 'v':
129 			vflag = 1;
130 			break;
131 		case 'W':
132 			Wflag = 1;
133 			break;
134 		default:
135 			usage();
136 		}
137 	argc -= optind;
138 	argv += optind;
139 
140 	if (argc < 1) {
141 		if (fflag)
142 			return 0;
143 		usage();
144 	}
145 
146 	checkdot(argv);
147 	uid = geteuid();
148 
149 	if (*argv) {
150 		stdin_ok = isatty(STDIN_FILENO);
151 
152 		if (rflag)
153 			rm_tree(argv);
154 		else
155 			rm_file(argv);
156 	}
157 
158 	exit (eval);
159 }
160 
161 void
162 rm_tree(char **argv)
163 {
164 	FTS *fts;
165 	FTSENT *p;
166 	int needstat;
167 	int flags;
168 	int rval;
169 
170 	/*
171 	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
172 	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
173 	 */
174 	needstat = !uid || (!fflag && !iflag && stdin_ok);
175 
176 	/*
177 	 * If the -i option is specified, the user can skip on the pre-order
178 	 * visit.  The fts_number field flags skipped directories.
179 	 */
180 #define	SKIPPED	1
181 
182 	flags = FTS_PHYSICAL;
183 	if (!needstat)
184 		flags |= FTS_NOSTAT;
185 	if (Wflag)
186 		flags |= FTS_WHITEOUT;
187 	if (!(fts = fts_open(argv, flags, NULL)))
188 		err(1, "fts_open");
189 	while ((p = fts_read(fts)) != NULL) {
190 		switch (p->fts_info) {
191 		case FTS_DNR:
192 			if (!fflag || p->fts_errno != ENOENT) {
193 				warnx("%s: %s",
194 				    p->fts_path, strerror(p->fts_errno));
195 				eval = 1;
196 			}
197 			continue;
198 		case FTS_ERR:
199 			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
200 		case FTS_NS:
201 			/*
202 			 * FTS_NS: assume that if can't stat the file, it
203 			 * can't be unlinked.
204 			 */
205 			if (!needstat)
206 				break;
207 			if (!fflag || p->fts_errno != ENOENT) {
208 				warnx("%s: %s",
209 				    p->fts_path, strerror(p->fts_errno));
210 				eval = 1;
211 			}
212 			continue;
213 		case FTS_D:
214 			/* Pre-order: give user chance to skip. */
215 			if (!fflag && !check(p->fts_path, p->fts_accpath,
216 			    p->fts_statp)) {
217 				(void)fts_set(fts, p, FTS_SKIP);
218 				p->fts_number = SKIPPED;
219 			}
220 			else if (!uid &&
221 				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
222 				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
223 				 chflags(p->fts_accpath,
224 					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
225 				goto err;
226 			continue;
227 		case FTS_DP:
228 			/* Post-order: see if user skipped. */
229 			if (p->fts_number == SKIPPED)
230 				continue;
231 			break;
232 		default:
233 			if (!fflag &&
234 			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
235 				continue;
236 		}
237 
238 		rval = 0;
239 		if (!uid &&
240 		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
241 		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
242 			rval = chflags(p->fts_accpath,
243 				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
244 		if (rval == 0) {
245 			/*
246 			 * If we can't read or search the directory, may still be
247 			 * able to remove it.  Don't print out the un{read,search}able
248 			 * message unless the remove fails.
249 			 */
250 			switch (p->fts_info) {
251 			case FTS_DP:
252 			case FTS_DNR:
253 				rval = rmdir(p->fts_accpath);
254 				if (rval == 0 || (fflag && errno == ENOENT)) {
255 					if (rval == 0 && vflag)
256 						(void)printf("%s\n",
257 						    p->fts_path);
258 					continue;
259 				}
260 				break;
261 
262 			case FTS_W:
263 				rval = undelete(p->fts_accpath);
264 				if (rval == 0 && (fflag && errno == ENOENT)) {
265 					if (vflag)
266 						(void)printf("%s\n",
267 						    p->fts_path);
268 					continue;
269 				}
270 				break;
271 
272 			default:
273 				if (Pflag)
274 					rm_overwrite(p->fts_accpath, NULL);
275 				rval = unlink(p->fts_accpath);
276 				if (rval == 0 || (fflag && errno == ENOENT)) {
277 					if (rval == 0 && vflag)
278 						(void)printf("%s\n",
279 						    p->fts_path);
280 					continue;
281 				}
282 			}
283 		}
284 err:
285 		warn("%s", p->fts_path);
286 		eval = 1;
287 	}
288 	if (errno)
289 		err(1, "fts_read");
290 }
291 
292 void
293 rm_file(char **argv)
294 {
295 	struct stat sb;
296 	int rval;
297 	char *f;
298 
299 	/*
300 	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
301 	 * to remove a directory is an error, so must always stat the file.
302 	 */
303 	while ((f = *argv++) != NULL) {
304 		/* Assume if can't stat the file, can't unlink it. */
305 		if (lstat(f, &sb)) {
306 			if (Wflag) {
307 				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
308 			} else {
309 				if (!fflag || errno != ENOENT) {
310 					warn("%s", f);
311 					eval = 1;
312 				}
313 				continue;
314 			}
315 		} else if (Wflag) {
316 			warnx("%s: %s", f, strerror(EEXIST));
317 			eval = 1;
318 			continue;
319 		}
320 
321 		if (S_ISDIR(sb.st_mode) && !dflag) {
322 			warnx("%s: is a directory", f);
323 			eval = 1;
324 			continue;
325 		}
326 		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
327 			continue;
328 		rval = 0;
329 		if (!uid &&
330 		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
331 		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
332 			rval = chflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
333 		if (rval == 0) {
334 			if (S_ISWHT(sb.st_mode))
335 				rval = undelete(f);
336 			else if (S_ISDIR(sb.st_mode))
337 				rval = rmdir(f);
338 			else {
339 				if (Pflag)
340 					rm_overwrite(f, &sb);
341 				rval = unlink(f);
342 			}
343 		}
344 		if (rval && (!fflag || errno != ENOENT)) {
345 			warn("%s", f);
346 			eval = 1;
347 		}
348 		if (vflag && rval == 0)
349 			(void)printf("%s\n", f);
350 	}
351 }
352 
353 /*
354  * rm_overwrite --
355  *	Overwrite the file 3 times with varying bit patterns.
356  *
357  * XXX
358  * This is a cheap way to *really* delete files.  Note that only regular
359  * files are deleted, directories (and therefore names) will remain.
360  * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
361  * System V file system).  In a logging file system, you'll have to have
362  * kernel support.
363  */
364 void
365 rm_overwrite(char *file, struct stat *sbp)
366 {
367 	struct stat sb;
368 	struct statfs fsb;
369 	off_t len;
370 	int bsize, fd, wlen;
371 	char *buf = NULL;
372 
373 	fd = -1;
374 	if (sbp == NULL) {
375 		if (lstat(file, &sb))
376 			goto err;
377 		sbp = &sb;
378 	}
379 	if (!S_ISREG(sbp->st_mode))
380 		return;
381 	if ((fd = open(file, O_WRONLY, 0)) == -1)
382 		goto err;
383 	if (fstatfs(fd, &fsb) == -1)
384 		goto err;
385 	bsize = MAX(fsb.f_iosize, 1024);
386 	if ((buf = malloc(bsize)) == NULL)
387 		err(1, "malloc");
388 
389 #define	PASS(byte) {							\
390 	memset(buf, byte, bsize);					\
391 	for (len = sbp->st_size; len > 0; len -= wlen) {		\
392 		wlen = len < bsize ? len : bsize;			\
393 		if (write(fd, buf, wlen) != wlen)			\
394 			goto err;					\
395 	}								\
396 }
397 	PASS(0xff);
398 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
399 		goto err;
400 	PASS(0x00);
401 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
402 		goto err;
403 	PASS(0xff);
404 	if (!fsync(fd) && !close(fd)) {
405 		free(buf);
406 		return;
407 	}
408 
409 err:	eval = 1;
410 	if (buf)
411 		free(buf);
412 	warn("%s", file);
413 }
414 
415 
416 int
417 check(char *path, char *name, struct stat *sp)
418 {
419 	int ch, first;
420 	char modep[15], *flagsp;
421 
422 	/* Check -i first. */
423 	if (iflag)
424 		(void)fprintf(stderr, "remove %s? ", path);
425 	else {
426 		/*
427 		 * If it's not a symbolic link and it's unwritable and we're
428 		 * talking to a terminal, ask.  Symbolic links are excluded
429 		 * because their permissions are meaningless.  Check stdin_ok
430 		 * first because we may not have stat'ed the file.
431 		 */
432 		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
433 		    (!access(name, W_OK) &&
434 		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
435 		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
436 			return (1);
437 		strmode(sp->st_mode, modep);
438 		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
439 			err(1, "fflagstostr");
440 		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
441 		    modep + 1, modep[9] == ' ' ? "" : " ",
442 		    user_from_uid(sp->st_uid, 0),
443 		    group_from_gid(sp->st_gid, 0),
444 		    *flagsp ? flagsp : "", *flagsp ? " " : "",
445 		    path);
446 		free(flagsp);
447 	}
448 	(void)fflush(stderr);
449 
450 	first = ch = getchar();
451 	while (ch != '\n' && ch != EOF)
452 		ch = getchar();
453 	return (first == 'y' || first == 'Y');
454 }
455 
456 #define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
457 void
458 checkdot(char **argv)
459 {
460 	char *p, **save, **t;
461 	int complained;
462 
463 	complained = 0;
464 	for (t = argv; *t;) {
465 		if ((p = strrchr(*t, '/')) != NULL)
466 			++p;
467 		else
468 			p = *t;
469 		if (ISDOT(p)) {
470 			if (!complained++)
471 				warnx("\".\" and \"..\" may not be removed");
472 			eval = 1;
473 			for (save = t; (t[0] = t[1]) != NULL; ++t)
474 				continue;
475 			t = save;
476 		} else
477 			++t;
478 	}
479 }
480 
481 void
482 usage(void)
483 {
484 
485 	(void)fprintf(stderr, "%s\n%s\n",
486 	    "usage: rm [-f | -i] [-dPRrvW] file ...",
487 	    "       unlink file");
488 	exit(EX_USAGE);
489 }
490