xref: /freebsd/bin/rm/rm.c (revision 3ff369fed2a08f32dda232c10470b949bef9489f)
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 #else
44 static const char rcsid[] =
45   "$FreeBSD$";
46 #endif
47 #endif /* not lint */
48 
49 #include <sys/stat.h>
50 #include <sys/param.h>
51 #include <sys/mount.h>
52 
53 #include <err.h>
54 #include <errno.h>
55 #include <fcntl.h>
56 #include <fts.h>
57 #include <grp.h>
58 #include <pwd.h>
59 #include <stdio.h>
60 #include <stdlib.h>
61 #include <string.h>
62 #include <sysexits.h>
63 #include <unistd.h>
64 
65 int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
66 uid_t uid;
67 
68 int	check(char *, char *, struct stat *);
69 void	checkdot(char **);
70 void	rm_file(char **);
71 void	rm_overwrite(char *, struct stat *);
72 void	rm_tree(char **);
73 void	usage(void);
74 
75 /*
76  * rm --
77  *	This rm is different from historic rm's, but is expected to match
78  *	POSIX 1003.2 behavior.  The most visible difference is that -f
79  *	has two specific effects now, ignore non-existent files and force
80  * 	file removal.
81  */
82 int
83 main(int argc, char *argv[])
84 {
85 	int ch, rflag;
86 	char *p;
87 
88 	/*
89 	 * Test for the special case where the utility is called as
90 	 * "unlink", for which the functionality provided is greatly
91 	 * simplified.
92 	 */
93 	if ((p = rindex(argv[0], '/')) == NULL)
94 		p = argv[0];
95 	else
96 		++p;
97 	if (strcmp(p, "unlink") == 0) {
98 		while (getopt(argc, argv, "") != -1)
99 			usage();
100 		argc -= optind;
101 		argv += optind;
102 		if (argc == 0)
103 			usage();
104 		rm_file(&argv[0]);
105 		exit(eval);
106 	}
107 
108 	Pflag = rflag = 0;
109 	while ((ch = getopt(argc, argv, "dfiPRrvW")) != -1)
110 		switch(ch) {
111 		case 'd':
112 			dflag = 1;
113 			break;
114 		case 'f':
115 			fflag = 1;
116 			iflag = 0;
117 			break;
118 		case 'i':
119 			fflag = 0;
120 			iflag = 1;
121 			break;
122 		case 'P':
123 			Pflag = 1;
124 			break;
125 		case 'R':
126 		case 'r':			/* Compatibility. */
127 			rflag = 1;
128 			break;
129 		case 'v':
130 			vflag = 1;
131 			break;
132 		case 'W':
133 			Wflag = 1;
134 			break;
135 		default:
136 			usage();
137 		}
138 	argc -= optind;
139 	argv += optind;
140 
141 	if (argc < 1) {
142 		if (fflag)
143 			return 0;
144 		usage();
145 	}
146 
147 	checkdot(argv);
148 	uid = geteuid();
149 
150 	if (*argv) {
151 		stdin_ok = isatty(STDIN_FILENO);
152 
153 		if (rflag)
154 			rm_tree(argv);
155 		else
156 			rm_file(argv);
157 	}
158 
159 	exit (eval);
160 }
161 
162 void
163 rm_tree(char **argv)
164 {
165 	FTS *fts;
166 	FTSENT *p;
167 	int needstat;
168 	int flags;
169 	int rval;
170 
171 	/*
172 	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
173 	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
174 	 */
175 	needstat = !uid || (!fflag && !iflag && stdin_ok);
176 
177 	/*
178 	 * If the -i option is specified, the user can skip on the pre-order
179 	 * visit.  The fts_number field flags skipped directories.
180 	 */
181 #define	SKIPPED	1
182 
183 	flags = FTS_PHYSICAL;
184 	if (!needstat)
185 		flags |= FTS_NOSTAT;
186 	if (Wflag)
187 		flags |= FTS_WHITEOUT;
188 	if (!(fts = fts_open(argv, flags, NULL)))
189 		err(1, NULL);
190 	while ((p = fts_read(fts)) != NULL) {
191 		switch (p->fts_info) {
192 		case FTS_DNR:
193 			if (!fflag || p->fts_errno != ENOENT) {
194 				warnx("%s: %s",
195 				    p->fts_path, strerror(p->fts_errno));
196 				eval = 1;
197 			}
198 			continue;
199 		case FTS_ERR:
200 			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
201 		case FTS_NS:
202 			/*
203 			 * FTS_NS: assume that if can't stat the file, it
204 			 * can't be unlinked.
205 			 */
206 			if (!needstat)
207 				break;
208 			if (!fflag || p->fts_errno != ENOENT) {
209 				warnx("%s: %s",
210 				    p->fts_path, strerror(p->fts_errno));
211 				eval = 1;
212 			}
213 			continue;
214 		case FTS_D:
215 			/* Pre-order: give user chance to skip. */
216 			if (!fflag && !check(p->fts_path, p->fts_accpath,
217 			    p->fts_statp)) {
218 				(void)fts_set(fts, p, FTS_SKIP);
219 				p->fts_number = SKIPPED;
220 			}
221 			else if (!uid &&
222 				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
223 				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
224 				 chflags(p->fts_accpath,
225 					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
226 				goto err;
227 			continue;
228 		case FTS_DP:
229 			/* Post-order: see if user skipped. */
230 			if (p->fts_number == SKIPPED)
231 				continue;
232 			break;
233 		default:
234 			if (!fflag &&
235 			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
236 				continue;
237 		}
238 
239 		rval = 0;
240 		if (!uid &&
241 		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
242 		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
243 			rval = chflags(p->fts_accpath,
244 				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
245 		if (rval == 0) {
246 			/*
247 			 * If we can't read or search the directory, may still be
248 			 * able to remove it.  Don't print out the un{read,search}able
249 			 * message unless the remove fails.
250 			 */
251 			switch (p->fts_info) {
252 			case FTS_DP:
253 			case FTS_DNR:
254 				rval = rmdir(p->fts_accpath);
255 				if (rval == 0 || (fflag && errno == ENOENT)) {
256 					if (rval == 0 && vflag)
257 						(void)printf("%s\n",
258 						    p->fts_path);
259 					continue;
260 				}
261 				break;
262 
263 			case FTS_W:
264 				rval = undelete(p->fts_accpath);
265 				if (rval == 0 && (fflag && errno == ENOENT)) {
266 					if (vflag)
267 						(void)printf("%s\n",
268 						    p->fts_path);
269 					continue;
270 				}
271 				break;
272 
273 			default:
274 				if (Pflag)
275 					rm_overwrite(p->fts_accpath, NULL);
276 				rval = unlink(p->fts_accpath);
277 				if (rval == 0 || (fflag && errno == ENOENT)) {
278 					if (rval == 0 && vflag)
279 						(void)printf("%s\n",
280 						    p->fts_path);
281 					continue;
282 				}
283 			}
284 		}
285 err:
286 		warn("%s", p->fts_path);
287 		eval = 1;
288 	}
289 	if (errno)
290 		err(1, "fts_read");
291 }
292 
293 void
294 rm_file(char **argv)
295 {
296 	struct stat sb;
297 	int rval;
298 	char *f;
299 
300 	/*
301 	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
302 	 * to remove a directory is an error, so must always stat the file.
303 	 */
304 	while ((f = *argv++) != NULL) {
305 		/* Assume if can't stat the file, can't unlink it. */
306 		if (lstat(f, &sb)) {
307 			if (Wflag) {
308 				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
309 			} else {
310 				if (!fflag || errno != ENOENT) {
311 					warn("%s", f);
312 					eval = 1;
313 				}
314 				continue;
315 			}
316 		} else if (Wflag) {
317 			warnx("%s: %s", f, strerror(EEXIST));
318 			eval = 1;
319 			continue;
320 		}
321 
322 		if (S_ISDIR(sb.st_mode) && !dflag) {
323 			warnx("%s: is a directory", f);
324 			eval = 1;
325 			continue;
326 		}
327 		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
328 			continue;
329 		rval = 0;
330 		if (!uid &&
331 		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
332 		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
333 			rval = chflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
334 		if (rval == 0) {
335 			if (S_ISWHT(sb.st_mode))
336 				rval = undelete(f);
337 			else if (S_ISDIR(sb.st_mode))
338 				rval = rmdir(f);
339 			else {
340 				if (Pflag)
341 					rm_overwrite(f, &sb);
342 				rval = unlink(f);
343 			}
344 		}
345 		if (rval && (!fflag || errno != ENOENT)) {
346 			warn("%s", f);
347 			eval = 1;
348 		}
349 		if (vflag && rval == 0)
350 			(void)printf("%s\n", f);
351 	}
352 }
353 
354 /*
355  * rm_overwrite --
356  *	Overwrite the file 3 times with varying bit patterns.
357  *
358  * XXX
359  * This is a cheap way to *really* delete files.  Note that only regular
360  * files are deleted, directories (and therefore names) will remain.
361  * Also, this assumes a fixed-block filesystem (like FFS, or a V7 or a
362  * System V filesystem).  In a logging filesystem, you'll have to have
363  * kernel support.
364  */
365 void
366 rm_overwrite(char *file, struct stat *sbp)
367 {
368 	struct stat sb;
369 	struct statfs fsb;
370 	off_t len;
371 	int bsize, fd, wlen;
372 	char *buf = NULL;
373 
374 	fd = -1;
375 	if (sbp == NULL) {
376 		if (lstat(file, &sb))
377 			goto err;
378 		sbp = &sb;
379 	}
380 	if (!S_ISREG(sbp->st_mode))
381 		return;
382 	if ((fd = open(file, O_WRONLY, 0)) == -1)
383 		goto err;
384 	if (fstatfs(fd, &fsb) == -1)
385 		goto err;
386 	bsize = MAX(fsb.f_iosize, 1024);
387 	if ((buf = malloc(bsize)) == NULL)
388 		err(1, "malloc");
389 
390 #define	PASS(byte) {							\
391 	memset(buf, byte, bsize);					\
392 	for (len = sbp->st_size; len > 0; len -= wlen) {		\
393 		wlen = len < bsize ? len : bsize;			\
394 		if (write(fd, buf, wlen) != wlen)			\
395 			goto err;					\
396 	}								\
397 }
398 	PASS(0xff);
399 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
400 		goto err;
401 	PASS(0x00);
402 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
403 		goto err;
404 	PASS(0xff);
405 	if (!fsync(fd) && !close(fd)) {
406 		free(buf);
407 		return;
408 	}
409 
410 err:	eval = 1;
411 	if (buf)
412 		free(buf);
413 	warn("%s", file);
414 }
415 
416 
417 int
418 check(char *path, char *name, struct stat *sp)
419 {
420 	int ch, first;
421 	char modep[15], *flagsp;
422 
423 	/* Check -i first. */
424 	if (iflag)
425 		(void)fprintf(stderr, "remove %s? ", path);
426 	else {
427 		/*
428 		 * If it's not a symbolic link and it's unwritable and we're
429 		 * talking to a terminal, ask.  Symbolic links are excluded
430 		 * because their permissions are meaningless.  Check stdin_ok
431 		 * first because we may not have stat'ed the file.
432 		 */
433 		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
434 		    (!access(name, W_OK) &&
435 		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
436 		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
437 			return (1);
438 		strmode(sp->st_mode, modep);
439 		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
440 			err(1, NULL);
441 		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
442 		    modep + 1, modep[9] == ' ' ? "" : " ",
443 		    user_from_uid(sp->st_uid, 0),
444 		    group_from_gid(sp->st_gid, 0),
445 		    *flagsp ? flagsp : "", *flagsp ? " " : "",
446 		    path);
447 		free(flagsp);
448 	}
449 	(void)fflush(stderr);
450 
451 	first = ch = getchar();
452 	while (ch != '\n' && ch != EOF)
453 		ch = getchar();
454 	return (first == 'y' || first == 'Y');
455 }
456 
457 #define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
458 void
459 checkdot(char **argv)
460 {
461 	char *p, **save, **t;
462 	int complained;
463 
464 	complained = 0;
465 	for (t = argv; *t;) {
466 		if ((p = strrchr(*t, '/')) != NULL)
467 			++p;
468 		else
469 			p = *t;
470 		if (ISDOT(p)) {
471 			if (!complained++)
472 				warnx("\".\" and \"..\" may not be removed");
473 			eval = 1;
474 			for (save = t; (t[0] = t[1]) != NULL; ++t)
475 				continue;
476 			t = save;
477 		} else
478 			++t;
479 	}
480 }
481 
482 void
483 usage(void)
484 {
485 
486 	(void)fprintf(stderr, "%s\n%s\n",
487 	    "usage: rm [-f | -i] [-dPRrvW] file ...",
488 	    "       unlink file");
489 	exit(EX_USAGE);
490 }
491