xref: /freebsd/bin/rm/rm.c (revision d2387d42b8da231a5b95cbc313825fb2aadf26f6)
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 #if 0
35 #ifndef lint
36 static const char copyright[] =
37 "@(#) Copyright (c) 1990, 1993, 1994\n\
38 	The Regents of the University of California.  All rights reserved.\n";
39 #endif /* not lint */
40 
41 #ifndef lint
42 static char sccsid[] = "@(#)rm.c	8.5 (Berkeley) 4/18/94";
43 #endif /* not lint */
44 #endif
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 int	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 			 * Assume that since fts_read() couldn't stat the
203 			 * file, it 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 			case FTS_NS:
273 				/*
274 				 * Assume that since fts_read() couldn't stat
275 				 * the file, it can't be unlinked.
276 				 */
277 				if (fflag)
278 					continue;
279 				/* FALLTHROUGH */
280 			default:
281 				if (Pflag)
282 					if (!rm_overwrite(p->fts_accpath, NULL))
283 						continue;
284 				rval = unlink(p->fts_accpath);
285 				if (rval == 0 || (fflag && errno == ENOENT)) {
286 					if (rval == 0 && vflag)
287 						(void)printf("%s\n",
288 						    p->fts_path);
289 					continue;
290 				}
291 			}
292 		}
293 err:
294 		warn("%s", p->fts_path);
295 		eval = 1;
296 	}
297 	if (errno)
298 		err(1, "fts_read");
299 }
300 
301 void
302 rm_file(char **argv)
303 {
304 	struct stat sb;
305 	int rval;
306 	char *f;
307 
308 	/*
309 	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
310 	 * to remove a directory is an error, so must always stat the file.
311 	 */
312 	while ((f = *argv++) != NULL) {
313 		/* Assume if can't stat the file, can't unlink it. */
314 		if (lstat(f, &sb)) {
315 			if (Wflag) {
316 				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
317 			} else {
318 				if (!fflag || errno != ENOENT) {
319 					warn("%s", f);
320 					eval = 1;
321 				}
322 				continue;
323 			}
324 		} else if (Wflag) {
325 			warnx("%s: %s", f, strerror(EEXIST));
326 			eval = 1;
327 			continue;
328 		}
329 
330 		if (S_ISDIR(sb.st_mode) && !dflag) {
331 			warnx("%s: is a directory", f);
332 			eval = 1;
333 			continue;
334 		}
335 		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
336 			continue;
337 		rval = 0;
338 		if (!uid &&
339 		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
340 		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
341 			rval = chflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
342 		if (rval == 0) {
343 			if (S_ISWHT(sb.st_mode))
344 				rval = undelete(f);
345 			else if (S_ISDIR(sb.st_mode))
346 				rval = rmdir(f);
347 			else {
348 				if (Pflag)
349 					if (!rm_overwrite(f, &sb))
350 						continue;
351 				rval = unlink(f);
352 			}
353 		}
354 		if (rval && (!fflag || errno != ENOENT)) {
355 			warn("%s", f);
356 			eval = 1;
357 		}
358 		if (vflag && rval == 0)
359 			(void)printf("%s\n", f);
360 	}
361 }
362 
363 /*
364  * rm_overwrite --
365  *	Overwrite the file 3 times with varying bit patterns.
366  *
367  * XXX
368  * This is a cheap way to *really* delete files.  Note that only regular
369  * files are deleted, directories (and therefore names) will remain.
370  * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
371  * System V file system).  In a logging file system, you'll have to have
372  * kernel support.
373  */
374 int
375 rm_overwrite(char *file, struct stat *sbp)
376 {
377 	struct stat sb;
378 	struct statfs fsb;
379 	off_t len;
380 	int bsize, fd, wlen;
381 	char *buf = NULL;
382 
383 	fd = -1;
384 	if (sbp == NULL) {
385 		if (lstat(file, &sb))
386 			goto err;
387 		sbp = &sb;
388 	}
389 	if (!S_ISREG(sbp->st_mode))
390 		return (1);
391 	if ((fd = open(file, O_WRONLY, 0)) == -1)
392 		goto err;
393 	if (fstatfs(fd, &fsb) == -1)
394 		goto err;
395 	bsize = MAX(fsb.f_iosize, 1024);
396 	if ((buf = malloc(bsize)) == NULL)
397 		err(1, "%s: malloc", file);
398 
399 #define	PASS(byte) {							\
400 	memset(buf, byte, bsize);					\
401 	for (len = sbp->st_size; len > 0; len -= wlen) {		\
402 		wlen = len < bsize ? len : bsize;			\
403 		if (write(fd, buf, wlen) != wlen)			\
404 			goto err;					\
405 	}								\
406 }
407 	PASS(0xff);
408 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
409 		goto err;
410 	PASS(0x00);
411 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
412 		goto err;
413 	PASS(0xff);
414 	if (!fsync(fd) && !close(fd)) {
415 		free(buf);
416 		return (1);
417 	}
418 
419 err:	eval = 1;
420 	if (buf)
421 		free(buf);
422 	if (fd != -1)
423 		close(fd);
424 	warn("%s", file);
425 	return (0);
426 }
427 
428 
429 int
430 check(char *path, char *name, struct stat *sp)
431 {
432 	int ch, first;
433 	char modep[15], *flagsp;
434 
435 	/* Check -i first. */
436 	if (iflag)
437 		(void)fprintf(stderr, "remove %s? ", path);
438 	else {
439 		/*
440 		 * If it's not a symbolic link and it's unwritable and we're
441 		 * talking to a terminal, ask.  Symbolic links are excluded
442 		 * because their permissions are meaningless.  Check stdin_ok
443 		 * first because we may not have stat'ed the file.
444 		 * Also skip this check if the -P option was specified because
445 		 * we will not be able to overwrite file contents and will
446 		 * barf later.
447 		 */
448 		if (!stdin_ok || S_ISLNK(sp->st_mode) || Pflag ||
449 		    (!access(name, W_OK) &&
450 		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
451 		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
452 			return (1);
453 		strmode(sp->st_mode, modep);
454 		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
455 			err(1, "fflagstostr");
456 		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
457 		    modep + 1, modep[9] == ' ' ? "" : " ",
458 		    user_from_uid(sp->st_uid, 0),
459 		    group_from_gid(sp->st_gid, 0),
460 		    *flagsp ? flagsp : "", *flagsp ? " " : "",
461 		    path);
462 		free(flagsp);
463 	}
464 	(void)fflush(stderr);
465 
466 	first = ch = getchar();
467 	while (ch != '\n' && ch != EOF)
468 		ch = getchar();
469 	return (first == 'y' || first == 'Y');
470 }
471 
472 #define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
473 void
474 checkdot(char **argv)
475 {
476 	char *p, **save, **t;
477 	int complained;
478 
479 	complained = 0;
480 	for (t = argv; *t;) {
481 		if ((p = strrchr(*t, '/')) != NULL)
482 			++p;
483 		else
484 			p = *t;
485 		if (ISDOT(p)) {
486 			if (!complained++)
487 				warnx("\".\" and \"..\" may not be removed");
488 			eval = 1;
489 			for (save = t; (t[0] = t[1]) != NULL; ++t)
490 				continue;
491 			t = save;
492 		} else
493 			++t;
494 	}
495 }
496 
497 void
498 usage(void)
499 {
500 
501 	(void)fprintf(stderr, "%s\n%s\n",
502 	    "usage: rm [-f | -i] [-dPRrvW] file ...",
503 	    "       unlink file");
504 	exit(EX_USAGE);
505 }
506