xref: /freebsd/bin/rm/rm.c (revision 641a6cfb86023499caafe26a4d821a0b885cf00b)
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  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if 0
31 #ifndef lint
32 static const char copyright[] =
33 "@(#) Copyright (c) 1990, 1993, 1994\n\
34 	The Regents of the University of California.  All rights reserved.\n";
35 #endif /* not lint */
36 
37 #ifndef lint
38 static char sccsid[] = "@(#)rm.c	8.5 (Berkeley) 4/18/94";
39 #endif /* not lint */
40 #endif
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
43 
44 #include <sys/stat.h>
45 #include <sys/param.h>
46 #include <sys/mount.h>
47 
48 #include <err.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <fts.h>
52 #include <grp.h>
53 #include <pwd.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <sysexits.h>
58 #include <unistd.h>
59 
60 static int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
61 static int rflag, Iflag;
62 static uid_t uid;
63 static volatile sig_atomic_t info;
64 
65 int	check(char *, char *, struct stat *);
66 int	check2(char **);
67 void	checkdot(char **);
68 void	checkslash(char **);
69 void	rm_file(char **);
70 int	rm_overwrite(char *, struct stat *);
71 void	rm_tree(char **);
72 static void siginfo(int __unused);
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;
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 = strrchr(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 != 1)
103 			usage();
104 		rm_file(&argv[0]);
105 		exit(eval);
106 	}
107 
108 	Pflag = rflag = 0;
109 	while ((ch = getopt(argc, argv, "dfiIPRrvW")) != -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 'I':
123 			Iflag = 1;
124 			break;
125 		case 'P':
126 			Pflag = 1;
127 			break;
128 		case 'R':
129 		case 'r':			/* Compatibility. */
130 			rflag = 1;
131 			break;
132 		case 'v':
133 			vflag = 1;
134 			break;
135 		case 'W':
136 			Wflag = 1;
137 			break;
138 		default:
139 			usage();
140 		}
141 	argc -= optind;
142 	argv += optind;
143 
144 	if (argc < 1) {
145 		if (fflag)
146 			return (0);
147 		usage();
148 	}
149 
150 	checkdot(argv);
151 	if (getenv("POSIXLY_CORRECT") == NULL)
152 		checkslash(argv);
153 	uid = geteuid();
154 
155 	(void)signal(SIGINFO, siginfo);
156 	if (*argv) {
157 		stdin_ok = isatty(STDIN_FILENO);
158 
159 		if (Iflag) {
160 			if (check2(argv) == 0)
161 				exit (1);
162 		}
163 		if (rflag)
164 			rm_tree(argv);
165 		else
166 			rm_file(argv);
167 	}
168 
169 	exit (eval);
170 }
171 
172 void
173 rm_tree(char **argv)
174 {
175 	FTS *fts;
176 	FTSENT *p;
177 	int needstat;
178 	int flags;
179 	int rval;
180 
181 	/*
182 	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
183 	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
184 	 */
185 	needstat = !uid || (!fflag && !iflag && stdin_ok);
186 
187 	/*
188 	 * If the -i option is specified, the user can skip on the pre-order
189 	 * visit.  The fts_number field flags skipped directories.
190 	 */
191 #define	SKIPPED	1
192 
193 	flags = FTS_PHYSICAL;
194 	if (!needstat)
195 		flags |= FTS_NOSTAT;
196 	if (Wflag)
197 		flags |= FTS_WHITEOUT;
198 	if (!(fts = fts_open(argv, flags, NULL))) {
199 		if (fflag && errno == ENOENT)
200 			return;
201 		err(1, "fts_open");
202 	}
203 	while ((p = fts_read(fts)) != NULL) {
204 		switch (p->fts_info) {
205 		case FTS_DNR:
206 			if (!fflag || p->fts_errno != ENOENT) {
207 				warnx("%s: %s",
208 				    p->fts_path, strerror(p->fts_errno));
209 				eval = 1;
210 			}
211 			continue;
212 		case FTS_ERR:
213 			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
214 		case FTS_NS:
215 			/*
216 			 * Assume that since fts_read() couldn't stat the
217 			 * file, it can't be unlinked.
218 			 */
219 			if (!needstat)
220 				break;
221 			if (!fflag || p->fts_errno != ENOENT) {
222 				warnx("%s: %s",
223 				    p->fts_path, strerror(p->fts_errno));
224 				eval = 1;
225 			}
226 			continue;
227 		case FTS_D:
228 			/* Pre-order: give user chance to skip. */
229 			if (!fflag && !check(p->fts_path, p->fts_accpath,
230 			    p->fts_statp)) {
231 				(void)fts_set(fts, p, FTS_SKIP);
232 				p->fts_number = SKIPPED;
233 			}
234 			else if (!uid &&
235 				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
236 				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
237 				 lchflags(p->fts_accpath,
238 					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
239 				goto err;
240 			continue;
241 		case FTS_DP:
242 			/* Post-order: see if user skipped. */
243 			if (p->fts_number == SKIPPED)
244 				continue;
245 			break;
246 		default:
247 			if (!fflag &&
248 			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
249 				continue;
250 		}
251 
252 		rval = 0;
253 		if (!uid &&
254 		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
255 		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
256 			rval = lchflags(p->fts_accpath,
257 				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
258 		if (rval == 0) {
259 			/*
260 			 * If we can't read or search the directory, may still be
261 			 * able to remove it.  Don't print out the un{read,search}able
262 			 * message unless the remove fails.
263 			 */
264 			switch (p->fts_info) {
265 			case FTS_DP:
266 			case FTS_DNR:
267 				rval = rmdir(p->fts_accpath);
268 				if (rval == 0 || (fflag && errno == ENOENT)) {
269 					if (rval == 0 && vflag)
270 						(void)printf("%s\n",
271 						    p->fts_path);
272 					if (rval == 0 && info) {
273 						info = 0;
274 						(void)printf("%s\n",
275 						    p->fts_path);
276 					}
277 					continue;
278 				}
279 				break;
280 
281 			case FTS_W:
282 				rval = undelete(p->fts_accpath);
283 				if (rval == 0 && (fflag && errno == ENOENT)) {
284 					if (vflag)
285 						(void)printf("%s\n",
286 						    p->fts_path);
287 					if (info) {
288 						info = 0;
289 						(void)printf("%s\n",
290 						    p->fts_path);
291 					}
292 					continue;
293 				}
294 				break;
295 
296 			case FTS_NS:
297 				/*
298 				 * Assume that since fts_read() couldn't stat
299 				 * the file, it can't be unlinked.
300 				 */
301 				if (fflag)
302 					continue;
303 				/* FALLTHROUGH */
304 
305 			case FTS_F:
306 			case FTS_NSOK:
307 				if (Pflag)
308 					if (!rm_overwrite(p->fts_accpath, p->fts_info ==
309 					    FTS_NSOK ? NULL : p->fts_statp))
310 						continue;
311 				/* FALLTHROUGH */
312 
313 			default:
314 				rval = unlink(p->fts_accpath);
315 				if (rval == 0 || (fflag && errno == ENOENT)) {
316 					if (rval == 0 && vflag)
317 						(void)printf("%s\n",
318 						    p->fts_path);
319 					if (rval == 0 && info) {
320 						info = 0;
321 						(void)printf("%s\n",
322 						    p->fts_path);
323 					}
324 					continue;
325 				}
326 			}
327 		}
328 err:
329 		warn("%s", p->fts_path);
330 		eval = 1;
331 	}
332 	if (errno)
333 		err(1, "fts_read");
334 	fts_close(fts);
335 }
336 
337 void
338 rm_file(char **argv)
339 {
340 	struct stat sb;
341 	int rval;
342 	char *f;
343 
344 	/*
345 	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
346 	 * to remove a directory is an error, so must always stat the file.
347 	 */
348 	while ((f = *argv++) != NULL) {
349 		/* Assume if can't stat the file, can't unlink it. */
350 		if (lstat(f, &sb)) {
351 			if (Wflag) {
352 				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
353 			} else {
354 				if (!fflag || errno != ENOENT) {
355 					warn("%s", f);
356 					eval = 1;
357 				}
358 				continue;
359 			}
360 		} else if (Wflag) {
361 			warnx("%s: %s", f, strerror(EEXIST));
362 			eval = 1;
363 			continue;
364 		}
365 
366 		if (S_ISDIR(sb.st_mode) && !dflag) {
367 			warnx("%s: is a directory", f);
368 			eval = 1;
369 			continue;
370 		}
371 		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
372 			continue;
373 		rval = 0;
374 		if (!uid && !S_ISWHT(sb.st_mode) &&
375 		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
376 		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
377 			rval = lchflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
378 		if (rval == 0) {
379 			if (S_ISWHT(sb.st_mode))
380 				rval = undelete(f);
381 			else if (S_ISDIR(sb.st_mode))
382 				rval = rmdir(f);
383 			else {
384 				if (Pflag)
385 					if (!rm_overwrite(f, &sb))
386 						continue;
387 				rval = unlink(f);
388 			}
389 		}
390 		if (rval && (!fflag || errno != ENOENT)) {
391 			warn("%s", f);
392 			eval = 1;
393 		}
394 		if (vflag && rval == 0)
395 			(void)printf("%s\n", f);
396 		if (info && rval == 0) {
397 			info = 0;
398 			(void)printf("%s\n", f);
399 		}
400 	}
401 }
402 
403 /*
404  * rm_overwrite --
405  *	Overwrite the file 3 times with varying bit patterns.
406  *
407  * XXX
408  * This is a cheap way to *really* delete files.  Note that only regular
409  * files are deleted, directories (and therefore names) will remain.
410  * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
411  * System V file system).  In a logging or COW file system, you'll have to
412  * have kernel support.
413  */
414 int
415 rm_overwrite(char *file, struct stat *sbp)
416 {
417 	struct stat sb, sb2;
418 	struct statfs fsb;
419 	off_t len;
420 	int bsize, fd, wlen;
421 	char *buf = NULL;
422 
423 	fd = -1;
424 	if (sbp == NULL) {
425 		if (lstat(file, &sb))
426 			goto err;
427 		sbp = &sb;
428 	}
429 	if (!S_ISREG(sbp->st_mode))
430 		return (1);
431 	if (sbp->st_nlink > 1 && !fflag) {
432 		warnx("%s (inode %u): not overwritten due to multiple links",
433 		    file, sbp->st_ino);
434 		return (0);
435 	}
436 	if ((fd = open(file, O_WRONLY|O_NONBLOCK|O_NOFOLLOW, 0)) == -1)
437 		goto err;
438 	if (fstat(fd, &sb2))
439 		goto err;
440 	if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino ||
441 	    !S_ISREG(sb2.st_mode)) {
442 		errno = EPERM;
443 		goto err;
444 	}
445 	if (fstatfs(fd, &fsb) == -1)
446 		goto err;
447 	bsize = MAX(fsb.f_iosize, 1024);
448 	if ((buf = malloc(bsize)) == NULL)
449 		err(1, "%s: malloc", file);
450 
451 #define	PASS(byte) {							\
452 	memset(buf, byte, bsize);					\
453 	for (len = sbp->st_size; len > 0; len -= wlen) {		\
454 		wlen = len < bsize ? len : bsize;			\
455 		if (write(fd, buf, wlen) != wlen)			\
456 			goto err;					\
457 	}								\
458 }
459 	PASS(0xff);
460 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
461 		goto err;
462 	PASS(0x00);
463 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
464 		goto err;
465 	PASS(0xff);
466 	if (!fsync(fd) && !close(fd)) {
467 		free(buf);
468 		return (1);
469 	}
470 
471 err:	eval = 1;
472 	if (buf)
473 		free(buf);
474 	if (fd != -1)
475 		close(fd);
476 	warn("%s", file);
477 	return (0);
478 }
479 
480 
481 int
482 check(char *path, char *name, struct stat *sp)
483 {
484 	int ch, first;
485 	char modep[15], *flagsp;
486 
487 	/* Check -i first. */
488 	if (iflag)
489 		(void)fprintf(stderr, "remove %s? ", path);
490 	else {
491 		/*
492 		 * If it's not a symbolic link and it's unwritable and we're
493 		 * talking to a terminal, ask.	Symbolic links are excluded
494 		 * because their permissions are meaningless.  Check stdin_ok
495 		 * first because we may not have stat'ed the file.
496 		 */
497 		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
498 		    (!access(name, W_OK) &&
499 		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
500 		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
501 			return (1);
502 		strmode(sp->st_mode, modep);
503 		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
504 			err(1, "fflagstostr");
505 		if (Pflag)
506 			errx(1,
507 			    "%s: -P was specified, but file is not writable",
508 			    path);
509 		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
510 		    modep + 1, modep[9] == ' ' ? "" : " ",
511 		    user_from_uid(sp->st_uid, 0),
512 		    group_from_gid(sp->st_gid, 0),
513 		    *flagsp ? flagsp : "", *flagsp ? " " : "",
514 		    path);
515 		free(flagsp);
516 	}
517 	(void)fflush(stderr);
518 
519 	first = ch = getchar();
520 	while (ch != '\n' && ch != EOF)
521 		ch = getchar();
522 	return (first == 'y' || first == 'Y');
523 }
524 
525 #define ISSLASH(a)	((a)[0] == '/' && (a)[1] == '\0')
526 void
527 checkslash(char **argv)
528 {
529 	char **t, **u;
530 	int complained;
531 
532 	complained = 0;
533 	for (t = argv; *t;) {
534 		if (ISSLASH(*t)) {
535 			if (!complained++)
536 				warnx("\"/\" may not be removed");
537 			eval = 1;
538 			for (u = t; u[0] != NULL; ++u)
539 				u[0] = u[1];
540 		} else {
541 			++t;
542 		}
543 	}
544 }
545 
546 int
547 check2(char **argv)
548 {
549 	struct stat st;
550 	int first;
551 	int ch;
552 	int fcount = 0;
553 	int dcount = 0;
554 	int i;
555 	const char *dname = NULL;
556 
557 	for (i = 0; argv[i]; ++i) {
558 		if (lstat(argv[i], &st) == 0) {
559 			if (S_ISDIR(st.st_mode)) {
560 				++dcount;
561 				dname = argv[i];    /* only used if 1 dir */
562 			} else {
563 				++fcount;
564 			}
565 		}
566 	}
567 	first = 0;
568 	while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
569 		if (dcount && rflag) {
570 			fprintf(stderr, "recursively remove");
571 			if (dcount == 1)
572 				fprintf(stderr, " %s", dname);
573 			else
574 				fprintf(stderr, " %d dirs", dcount);
575 			if (fcount == 1)
576 				fprintf(stderr, " and 1 file");
577 			else if (fcount > 1)
578 				fprintf(stderr, " and %d files", fcount);
579 		} else if (dcount + fcount > 3) {
580 			fprintf(stderr, "remove %d files", dcount + fcount);
581 		} else {
582 			return(1);
583 		}
584 		fprintf(stderr, "? ");
585 		fflush(stderr);
586 
587 		first = ch = getchar();
588 		while (ch != '\n' && ch != EOF)
589 			ch = getchar();
590 		if (ch == EOF)
591 			break;
592 	}
593 	return (first == 'y' || first == 'Y');
594 }
595 
596 #define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
597 void
598 checkdot(char **argv)
599 {
600 	char *p, **save, **t;
601 	int complained;
602 
603 	complained = 0;
604 	for (t = argv; *t;) {
605 		if ((p = strrchr(*t, '/')) != NULL)
606 			++p;
607 		else
608 			p = *t;
609 		if (ISDOT(p)) {
610 			if (!complained++)
611 				warnx("\".\" and \"..\" may not be removed");
612 			eval = 1;
613 			for (save = t; (t[0] = t[1]) != NULL; ++t)
614 				continue;
615 			t = save;
616 		} else
617 			++t;
618 	}
619 }
620 
621 void
622 usage(void)
623 {
624 
625 	(void)fprintf(stderr, "%s\n%s\n",
626 	    "usage: rm [-f | -i] [-dIPRrvW] file ...",
627 	    "       unlink file");
628 	exit(EX_USAGE);
629 }
630 
631 static void
632 siginfo(int sig __unused)
633 {
634 
635 	info = 1;
636 }
637