xref: /freebsd/bin/rm/rm.c (revision c11e094d96120a2e0e726ed9705ae0ec08db49b6)
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 		if (argc == 2) {
99 			rm_file(&argv[1]);
100 			exit(eval);
101 		} else
102 			usage();
103 	}
104 
105 	Pflag = rflag = 0;
106 	while ((ch = getopt(argc, argv, "dfiPRrvW")) != -1)
107 		switch(ch) {
108 		case 'd':
109 			dflag = 1;
110 			break;
111 		case 'f':
112 			fflag = 1;
113 			iflag = 0;
114 			break;
115 		case 'i':
116 			fflag = 0;
117 			iflag = 1;
118 			break;
119 		case 'P':
120 			Pflag = 1;
121 			break;
122 		case 'R':
123 		case 'r':			/* Compatibility. */
124 			rflag = 1;
125 			break;
126 		case 'v':
127 			vflag = 1;
128 			break;
129 		case 'W':
130 			Wflag = 1;
131 			break;
132 		default:
133 			usage();
134 		}
135 	argc -= optind;
136 	argv += optind;
137 
138 	if (argc < 1) {
139 		if (fflag)
140 			return 0;
141 		usage();
142 	}
143 
144 	checkdot(argv);
145 	uid = geteuid();
146 
147 	if (*argv) {
148 		stdin_ok = isatty(STDIN_FILENO);
149 
150 		if (rflag)
151 			rm_tree(argv);
152 		else
153 			rm_file(argv);
154 	}
155 
156 	exit (eval);
157 }
158 
159 void
160 rm_tree(char **argv)
161 {
162 	FTS *fts;
163 	FTSENT *p;
164 	int needstat;
165 	int flags;
166 	int rval;
167 
168 	/*
169 	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
170 	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
171 	 */
172 	needstat = !uid || (!fflag && !iflag && stdin_ok);
173 
174 	/*
175 	 * If the -i option is specified, the user can skip on the pre-order
176 	 * visit.  The fts_number field flags skipped directories.
177 	 */
178 #define	SKIPPED	1
179 
180 	flags = FTS_PHYSICAL;
181 	if (!needstat)
182 		flags |= FTS_NOSTAT;
183 	if (Wflag)
184 		flags |= FTS_WHITEOUT;
185 	if (!(fts = fts_open(argv, flags, NULL)))
186 		err(1, NULL);
187 	while ((p = fts_read(fts)) != NULL) {
188 		switch (p->fts_info) {
189 		case FTS_DNR:
190 			if (!fflag || p->fts_errno != ENOENT) {
191 				warnx("%s: %s",
192 				    p->fts_path, strerror(p->fts_errno));
193 				eval = 1;
194 			}
195 			continue;
196 		case FTS_ERR:
197 			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
198 		case FTS_NS:
199 			/*
200 			 * FTS_NS: assume that if can't stat the file, it
201 			 * can't be unlinked.
202 			 */
203 			if (!needstat)
204 				break;
205 			if (!fflag || p->fts_errno != ENOENT) {
206 				warnx("%s: %s",
207 				    p->fts_path, strerror(p->fts_errno));
208 				eval = 1;
209 			}
210 			continue;
211 		case FTS_D:
212 			/* Pre-order: give user chance to skip. */
213 			if (!fflag && !check(p->fts_path, p->fts_accpath,
214 			    p->fts_statp)) {
215 				(void)fts_set(fts, p, FTS_SKIP);
216 				p->fts_number = SKIPPED;
217 			}
218 			else if (!uid &&
219 				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
220 				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
221 				 chflags(p->fts_accpath,
222 					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
223 				goto err;
224 			continue;
225 		case FTS_DP:
226 			/* Post-order: see if user skipped. */
227 			if (p->fts_number == SKIPPED)
228 				continue;
229 			break;
230 		default:
231 			if (!fflag &&
232 			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
233 				continue;
234 		}
235 
236 		rval = 0;
237 		if (!uid &&
238 		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
239 		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
240 			rval = chflags(p->fts_accpath,
241 				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
242 		if (rval == 0) {
243 			/*
244 			 * If we can't read or search the directory, may still be
245 			 * able to remove it.  Don't print out the un{read,search}able
246 			 * message unless the remove fails.
247 			 */
248 			switch (p->fts_info) {
249 			case FTS_DP:
250 			case FTS_DNR:
251 				rval = rmdir(p->fts_accpath);
252 				if (rval == 0 || (fflag && errno == ENOENT)) {
253 					if (rval == 0 && vflag)
254 						(void)printf("%s\n",
255 						    p->fts_path);
256 					continue;
257 				}
258 				break;
259 
260 			case FTS_W:
261 				rval = undelete(p->fts_accpath);
262 				if (rval == 0 && (fflag && errno == ENOENT)) {
263 					if (vflag)
264 						(void)printf("%s\n",
265 						    p->fts_path);
266 					continue;
267 				}
268 				break;
269 
270 			default:
271 				if (Pflag)
272 					rm_overwrite(p->fts_accpath, NULL);
273 				rval = unlink(p->fts_accpath);
274 				if (rval == 0 || (fflag && errno == ENOENT)) {
275 					if (rval == 0 && vflag)
276 						(void)printf("%s\n",
277 						    p->fts_path);
278 					continue;
279 				}
280 			}
281 		}
282 err:
283 		warn("%s", p->fts_path);
284 		eval = 1;
285 	}
286 	if (errno)
287 		err(1, "fts_read");
288 }
289 
290 void
291 rm_file(char **argv)
292 {
293 	struct stat sb;
294 	int rval;
295 	char *f;
296 
297 	/*
298 	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
299 	 * to remove a directory is an error, so must always stat the file.
300 	 */
301 	while ((f = *argv++) != NULL) {
302 		/* Assume if can't stat the file, can't unlink it. */
303 		if (lstat(f, &sb)) {
304 			if (Wflag) {
305 				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
306 			} else {
307 				if (!fflag || errno != ENOENT) {
308 					warn("%s", f);
309 					eval = 1;
310 				}
311 				continue;
312 			}
313 		} else if (Wflag) {
314 			warnx("%s: %s", f, strerror(EEXIST));
315 			eval = 1;
316 			continue;
317 		}
318 
319 		if (S_ISDIR(sb.st_mode) && !dflag) {
320 			warnx("%s: is a directory", f);
321 			eval = 1;
322 			continue;
323 		}
324 		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
325 			continue;
326 		rval = 0;
327 		if (!uid &&
328 		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
329 		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
330 			rval = chflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
331 		if (rval == 0) {
332 			if (S_ISWHT(sb.st_mode))
333 				rval = undelete(f);
334 			else if (S_ISDIR(sb.st_mode))
335 				rval = rmdir(f);
336 			else {
337 				if (Pflag)
338 					rm_overwrite(f, &sb);
339 				rval = unlink(f);
340 			}
341 		}
342 		if (rval && (!fflag || errno != ENOENT)) {
343 			warn("%s", f);
344 			eval = 1;
345 		}
346 		if (vflag && rval == 0)
347 			(void)printf("%s\n", f);
348 	}
349 }
350 
351 /*
352  * rm_overwrite --
353  *	Overwrite the file 3 times with varying bit patterns.
354  *
355  * XXX
356  * This is a cheap way to *really* delete files.  Note that only regular
357  * files are deleted, directories (and therefore names) will remain.
358  * Also, this assumes a fixed-block filesystem (like FFS, or a V7 or a
359  * System V filesystem).  In a logging filesystem, you'll have to have
360  * kernel support.
361  */
362 void
363 rm_overwrite(char *file, struct stat *sbp)
364 {
365 	struct stat sb;
366 	struct statfs fsb;
367 	off_t len;
368 	int bsize, fd, wlen;
369 	char *buf = NULL;
370 
371 	fd = -1;
372 	if (sbp == NULL) {
373 		if (lstat(file, &sb))
374 			goto err;
375 		sbp = &sb;
376 	}
377 	if (!S_ISREG(sbp->st_mode))
378 		return;
379 	if ((fd = open(file, O_WRONLY, 0)) == -1)
380 		goto err;
381 	if (fstatfs(fd, &fsb) == -1)
382 		goto err;
383 	bsize = MAX(fsb.f_iosize, 1024);
384 	if ((buf = malloc(bsize)) == NULL)
385 		err(1, "malloc");
386 
387 #define	PASS(byte) {							\
388 	memset(buf, byte, bsize);					\
389 	for (len = sbp->st_size; len > 0; len -= wlen) {		\
390 		wlen = len < bsize ? len : bsize;			\
391 		if (write(fd, buf, wlen) != wlen)			\
392 			goto err;					\
393 	}								\
394 }
395 	PASS(0xff);
396 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
397 		goto err;
398 	PASS(0x00);
399 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
400 		goto err;
401 	PASS(0xff);
402 	if (!fsync(fd) && !close(fd)) {
403 		free(buf);
404 		return;
405 	}
406 
407 err:	eval = 1;
408 	if (buf)
409 		free(buf);
410 	warn("%s", file);
411 }
412 
413 
414 int
415 check(char *path, char *name, struct stat *sp)
416 {
417 	int ch, first;
418 	char modep[15], *flagsp;
419 
420 	/* Check -i first. */
421 	if (iflag)
422 		(void)fprintf(stderr, "remove %s? ", path);
423 	else {
424 		/*
425 		 * If it's not a symbolic link and it's unwritable and we're
426 		 * talking to a terminal, ask.  Symbolic links are excluded
427 		 * because their permissions are meaningless.  Check stdin_ok
428 		 * first because we may not have stat'ed the file.
429 		 */
430 		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
431 		    (!access(name, W_OK) &&
432 		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
433 		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
434 			return (1);
435 		strmode(sp->st_mode, modep);
436 		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
437 			err(1, NULL);
438 		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
439 		    modep + 1, modep[9] == ' ' ? "" : " ",
440 		    user_from_uid(sp->st_uid, 0),
441 		    group_from_gid(sp->st_gid, 0),
442 		    *flagsp ? flagsp : "", *flagsp ? " " : "",
443 		    path);
444 		free(flagsp);
445 	}
446 	(void)fflush(stderr);
447 
448 	first = ch = getchar();
449 	while (ch != '\n' && ch != EOF)
450 		ch = getchar();
451 	return (first == 'y' || first == 'Y');
452 }
453 
454 #define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
455 void
456 checkdot(char **argv)
457 {
458 	char *p, **save, **t;
459 	int complained;
460 
461 	complained = 0;
462 	for (t = argv; *t;) {
463 		if ((p = strrchr(*t, '/')) != NULL)
464 			++p;
465 		else
466 			p = *t;
467 		if (ISDOT(p)) {
468 			if (!complained++)
469 				warnx("\".\" and \"..\" may not be removed");
470 			eval = 1;
471 			for (save = t; (t[0] = t[1]) != NULL; ++t)
472 				continue;
473 			t = save;
474 		} else
475 			++t;
476 	}
477 }
478 
479 void
480 usage(void)
481 {
482 
483 	(void)fprintf(stderr, "%s\n%s\n",
484 	    "usage: rm [-f | -i] [-dPRrvW] file ...",
485 	    "       unlink file");
486 	exit(EX_USAGE);
487 }
488