xref: /freebsd/bin/rm/rm.c (revision cbd30a72ca196976c1c700400ecd424baa1b9c16)
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. 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 <locale.h>
54 #include <pwd.h>
55 #include <stdint.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <sysexits.h>
60 #include <unistd.h>
61 
62 static int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
63 static int rflag, Iflag, xflag;
64 static uid_t uid;
65 static volatile sig_atomic_t info;
66 
67 static int	check(const char *, const char *, struct stat *);
68 static int	check2(char **);
69 static void	checkdot(char **);
70 static void	checkslash(char **);
71 static void	rm_file(char **);
72 static int	rm_overwrite(const char *, struct stat *);
73 static void	rm_tree(char **);
74 static void siginfo(int __unused);
75 static void	usage(void);
76 
77 /*
78  * rm --
79  *	This rm is different from historic rm's, but is expected to match
80  *	POSIX 1003.2 behavior.	The most visible difference is that -f
81  *	has two specific effects now, ignore non-existent files and force
82  *	file removal.
83  */
84 int
85 main(int argc, char *argv[])
86 {
87 	int ch;
88 	char *p;
89 
90 	(void)setlocale(LC_ALL, "");
91 
92 	/*
93 	 * Test for the special case where the utility is called as
94 	 * "unlink", for which the functionality provided is greatly
95 	 * simplified.
96 	 */
97 	if ((p = strrchr(argv[0], '/')) == NULL)
98 		p = argv[0];
99 	else
100 		++p;
101 	if (strcmp(p, "unlink") == 0) {
102 		while (getopt(argc, argv, "") != -1)
103 			usage();
104 		argc -= optind;
105 		argv += optind;
106 		if (argc != 1)
107 			usage();
108 		rm_file(&argv[0]);
109 		exit(eval);
110 	}
111 
112 	Pflag = rflag = xflag = 0;
113 	while ((ch = getopt(argc, argv, "dfiIPRrvWx")) != -1)
114 		switch(ch) {
115 		case 'd':
116 			dflag = 1;
117 			break;
118 		case 'f':
119 			fflag = 1;
120 			iflag = 0;
121 			break;
122 		case 'i':
123 			fflag = 0;
124 			iflag = 1;
125 			break;
126 		case 'I':
127 			Iflag = 1;
128 			break;
129 		case 'P':
130 			Pflag = 1;
131 			break;
132 		case 'R':
133 		case 'r':			/* Compatibility. */
134 			rflag = 1;
135 			break;
136 		case 'v':
137 			vflag = 1;
138 			break;
139 		case 'W':
140 			Wflag = 1;
141 			break;
142 		case 'x':
143 			xflag = 1;
144 			break;
145 		default:
146 			usage();
147 		}
148 	argc -= optind;
149 	argv += optind;
150 
151 	if (argc < 1) {
152 		if (fflag)
153 			return (0);
154 		usage();
155 	}
156 
157 	checkdot(argv);
158 	checkslash(argv);
159 	uid = geteuid();
160 
161 	(void)signal(SIGINFO, siginfo);
162 	if (*argv) {
163 		stdin_ok = isatty(STDIN_FILENO);
164 
165 		if (Iflag) {
166 			if (check2(argv) == 0)
167 				exit (1);
168 		}
169 		if (rflag)
170 			rm_tree(argv);
171 		else
172 			rm_file(argv);
173 	}
174 
175 	exit (eval);
176 }
177 
178 static void
179 rm_tree(char **argv)
180 {
181 	FTS *fts;
182 	FTSENT *p;
183 	int needstat;
184 	int flags;
185 	int rval;
186 
187 	/*
188 	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
189 	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
190 	 */
191 	needstat = !uid || (!fflag && !iflag && stdin_ok);
192 
193 	/*
194 	 * If the -i option is specified, the user can skip on the pre-order
195 	 * visit.  The fts_number field flags skipped directories.
196 	 */
197 #define	SKIPPED	1
198 
199 	flags = FTS_PHYSICAL;
200 	if (!needstat)
201 		flags |= FTS_NOSTAT;
202 	if (Wflag)
203 		flags |= FTS_WHITEOUT;
204 	if (xflag)
205 		flags |= FTS_XDEV;
206 	if (!(fts = fts_open(argv, flags, NULL))) {
207 		if (fflag && errno == ENOENT)
208 			return;
209 		err(1, "fts_open");
210 	}
211 	while ((p = fts_read(fts)) != NULL) {
212 		switch (p->fts_info) {
213 		case FTS_DNR:
214 			if (!fflag || p->fts_errno != ENOENT) {
215 				warnx("%s: %s",
216 				    p->fts_path, strerror(p->fts_errno));
217 				eval = 1;
218 			}
219 			continue;
220 		case FTS_ERR:
221 			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
222 		case FTS_NS:
223 			/*
224 			 * Assume that since fts_read() couldn't stat the
225 			 * file, it can't be unlinked.
226 			 */
227 			if (!needstat)
228 				break;
229 			if (!fflag || p->fts_errno != ENOENT) {
230 				warnx("%s: %s",
231 				    p->fts_path, strerror(p->fts_errno));
232 				eval = 1;
233 			}
234 			continue;
235 		case FTS_D:
236 			/* Pre-order: give user chance to skip. */
237 			if (!fflag && !check(p->fts_path, p->fts_accpath,
238 			    p->fts_statp)) {
239 				(void)fts_set(fts, p, FTS_SKIP);
240 				p->fts_number = SKIPPED;
241 			}
242 			else if (!uid &&
243 				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
244 				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
245 				 lchflags(p->fts_accpath,
246 					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
247 				goto err;
248 			continue;
249 		case FTS_DP:
250 			/* Post-order: see if user skipped. */
251 			if (p->fts_number == SKIPPED)
252 				continue;
253 			break;
254 		default:
255 			if (!fflag &&
256 			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
257 				continue;
258 		}
259 
260 		rval = 0;
261 		if (!uid &&
262 		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
263 		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
264 			rval = lchflags(p->fts_accpath,
265 				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
266 		if (rval == 0) {
267 			/*
268 			 * If we can't read or search the directory, may still be
269 			 * able to remove it.  Don't print out the un{read,search}able
270 			 * message unless the remove fails.
271 			 */
272 			switch (p->fts_info) {
273 			case FTS_DP:
274 			case FTS_DNR:
275 				rval = rmdir(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 					if (rval == 0 && info) {
281 						info = 0;
282 						(void)printf("%s\n",
283 						    p->fts_path);
284 					}
285 					continue;
286 				}
287 				break;
288 
289 			case FTS_W:
290 				rval = undelete(p->fts_accpath);
291 				if (rval == 0 && (fflag && errno == ENOENT)) {
292 					if (vflag)
293 						(void)printf("%s\n",
294 						    p->fts_path);
295 					if (info) {
296 						info = 0;
297 						(void)printf("%s\n",
298 						    p->fts_path);
299 					}
300 					continue;
301 				}
302 				break;
303 
304 			case FTS_NS:
305 				/*
306 				 * Assume that since fts_read() couldn't stat
307 				 * the file, it can't be unlinked.
308 				 */
309 				if (fflag)
310 					continue;
311 				/* FALLTHROUGH */
312 
313 			case FTS_F:
314 			case FTS_NSOK:
315 				if (Pflag)
316 					if (!rm_overwrite(p->fts_accpath, p->fts_info ==
317 					    FTS_NSOK ? NULL : p->fts_statp))
318 						continue;
319 				/* FALLTHROUGH */
320 
321 			default:
322 				rval = unlink(p->fts_accpath);
323 				if (rval == 0 || (fflag && errno == ENOENT)) {
324 					if (rval == 0 && vflag)
325 						(void)printf("%s\n",
326 						    p->fts_path);
327 					if (rval == 0 && info) {
328 						info = 0;
329 						(void)printf("%s\n",
330 						    p->fts_path);
331 					}
332 					continue;
333 				}
334 			}
335 		}
336 err:
337 		warn("%s", p->fts_path);
338 		eval = 1;
339 	}
340 	if (!fflag && errno)
341 		err(1, "fts_read");
342 	fts_close(fts);
343 }
344 
345 static void
346 rm_file(char **argv)
347 {
348 	struct stat sb;
349 	int rval;
350 	char *f;
351 
352 	/*
353 	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
354 	 * to remove a directory is an error, so must always stat the file.
355 	 */
356 	while ((f = *argv++) != NULL) {
357 		/* Assume if can't stat the file, can't unlink it. */
358 		if (lstat(f, &sb)) {
359 			if (Wflag) {
360 				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
361 			} else {
362 				if (!fflag || errno != ENOENT) {
363 					warn("%s", f);
364 					eval = 1;
365 				}
366 				continue;
367 			}
368 		} else if (Wflag) {
369 			warnx("%s: %s", f, strerror(EEXIST));
370 			eval = 1;
371 			continue;
372 		}
373 
374 		if (S_ISDIR(sb.st_mode) && !dflag) {
375 			warnx("%s: is a directory", f);
376 			eval = 1;
377 			continue;
378 		}
379 		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
380 			continue;
381 		rval = 0;
382 		if (!uid && !S_ISWHT(sb.st_mode) &&
383 		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
384 		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
385 			rval = lchflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
386 		if (rval == 0) {
387 			if (S_ISWHT(sb.st_mode))
388 				rval = undelete(f);
389 			else if (S_ISDIR(sb.st_mode))
390 				rval = rmdir(f);
391 			else {
392 				if (Pflag)
393 					if (!rm_overwrite(f, &sb))
394 						continue;
395 				rval = unlink(f);
396 			}
397 		}
398 		if (rval && (!fflag || errno != ENOENT)) {
399 			warn("%s", f);
400 			eval = 1;
401 		}
402 		if (vflag && rval == 0)
403 			(void)printf("%s\n", f);
404 		if (info && rval == 0) {
405 			info = 0;
406 			(void)printf("%s\n", f);
407 		}
408 	}
409 }
410 
411 /*
412  * rm_overwrite --
413  *	Overwrite the file 3 times with varying bit patterns.
414  *
415  * XXX
416  * This is a cheap way to *really* delete files.  Note that only regular
417  * files are deleted, directories (and therefore names) will remain.
418  * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
419  * System V file system).  In a logging or COW file system, you'll have to
420  * have kernel support.
421  */
422 static int
423 rm_overwrite(const char *file, struct stat *sbp)
424 {
425 	struct stat sb, sb2;
426 	struct statfs fsb;
427 	off_t len;
428 	int bsize, fd, wlen;
429 	char *buf = NULL;
430 
431 	fd = -1;
432 	if (sbp == NULL) {
433 		if (lstat(file, &sb))
434 			goto err;
435 		sbp = &sb;
436 	}
437 	if (!S_ISREG(sbp->st_mode))
438 		return (1);
439 	if (sbp->st_nlink > 1 && !fflag) {
440 		warnx("%s (inode %ju): not overwritten due to multiple links",
441 		    file, (uintmax_t)sbp->st_ino);
442 		return (0);
443 	}
444 	if ((fd = open(file, O_WRONLY|O_NONBLOCK|O_NOFOLLOW, 0)) == -1)
445 		goto err;
446 	if (fstat(fd, &sb2))
447 		goto err;
448 	if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino ||
449 	    !S_ISREG(sb2.st_mode)) {
450 		errno = EPERM;
451 		goto err;
452 	}
453 	if (fstatfs(fd, &fsb) == -1)
454 		goto err;
455 	bsize = MAX(fsb.f_iosize, 1024);
456 	if ((buf = malloc(bsize)) == NULL)
457 		err(1, "%s: malloc", file);
458 
459 #define	PASS(byte) {							\
460 	memset(buf, byte, bsize);					\
461 	for (len = sbp->st_size; len > 0; len -= wlen) {		\
462 		wlen = len < bsize ? len : bsize;			\
463 		if (write(fd, buf, wlen) != wlen)			\
464 			goto err;					\
465 	}								\
466 }
467 	PASS(0xff);
468 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
469 		goto err;
470 	PASS(0x00);
471 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
472 		goto err;
473 	PASS(0xff);
474 	if (!fsync(fd) && !close(fd)) {
475 		free(buf);
476 		return (1);
477 	}
478 
479 err:	eval = 1;
480 	if (buf)
481 		free(buf);
482 	if (fd != -1)
483 		close(fd);
484 	warn("%s", file);
485 	return (0);
486 }
487 
488 
489 static int
490 check(const char *path, const char *name, struct stat *sp)
491 {
492 	int ch, first;
493 	char modep[15], *flagsp;
494 
495 	/* Check -i first. */
496 	if (iflag)
497 		(void)fprintf(stderr, "remove %s? ", path);
498 	else {
499 		/*
500 		 * If it's not a symbolic link and it's unwritable and we're
501 		 * talking to a terminal, ask.  Symbolic links are excluded
502 		 * because their permissions are meaningless.  Check stdin_ok
503 		 * first because we may not have stat'ed the file.
504 		 */
505 		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
506 		    (!access(name, W_OK) &&
507 		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
508 		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
509 			return (1);
510 		strmode(sp->st_mode, modep);
511 		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
512 			err(1, "fflagstostr");
513 		if (Pflag)
514 			errx(1,
515 			    "%s: -P was specified, but file is not writable",
516 			    path);
517 		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
518 		    modep + 1, modep[9] == ' ' ? "" : " ",
519 		    user_from_uid(sp->st_uid, 0),
520 		    group_from_gid(sp->st_gid, 0),
521 		    *flagsp ? flagsp : "", *flagsp ? " " : "",
522 		    path);
523 		free(flagsp);
524 	}
525 	(void)fflush(stderr);
526 
527 	first = ch = getchar();
528 	while (ch != '\n' && ch != EOF)
529 		ch = getchar();
530 	return (first == 'y' || first == 'Y');
531 }
532 
533 #define ISSLASH(a)	((a)[0] == '/' && (a)[1] == '\0')
534 static void
535 checkslash(char **argv)
536 {
537 	char **t, **u;
538 	int complained;
539 
540 	complained = 0;
541 	for (t = argv; *t;) {
542 		if (ISSLASH(*t)) {
543 			if (!complained++)
544 				warnx("\"/\" may not be removed");
545 			eval = 1;
546 			for (u = t; u[0] != NULL; ++u)
547 				u[0] = u[1];
548 		} else {
549 			++t;
550 		}
551 	}
552 }
553 
554 static int
555 check2(char **argv)
556 {
557 	struct stat st;
558 	int first;
559 	int ch;
560 	int fcount = 0;
561 	int dcount = 0;
562 	int i;
563 	const char *dname = NULL;
564 
565 	for (i = 0; argv[i]; ++i) {
566 		if (lstat(argv[i], &st) == 0) {
567 			if (S_ISDIR(st.st_mode)) {
568 				++dcount;
569 				dname = argv[i];    /* only used if 1 dir */
570 			} else {
571 				++fcount;
572 			}
573 		}
574 	}
575 	first = 0;
576 	while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
577 		if (dcount && rflag) {
578 			fprintf(stderr, "recursively remove");
579 			if (dcount == 1)
580 				fprintf(stderr, " %s", dname);
581 			else
582 				fprintf(stderr, " %d dirs", dcount);
583 			if (fcount == 1)
584 				fprintf(stderr, " and 1 file");
585 			else if (fcount > 1)
586 				fprintf(stderr, " and %d files", fcount);
587 		} else if (dcount + fcount > 3) {
588 			fprintf(stderr, "remove %d files", dcount + fcount);
589 		} else {
590 			return(1);
591 		}
592 		fprintf(stderr, "? ");
593 		fflush(stderr);
594 
595 		first = ch = getchar();
596 		while (ch != '\n' && ch != EOF)
597 			ch = getchar();
598 		if (ch == EOF)
599 			break;
600 	}
601 	return (first == 'y' || first == 'Y');
602 }
603 
604 #define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
605 static void
606 checkdot(char **argv)
607 {
608 	char *p, **save, **t;
609 	int complained;
610 
611 	complained = 0;
612 	for (t = argv; *t;) {
613 		if ((p = strrchr(*t, '/')) != NULL)
614 			++p;
615 		else
616 			p = *t;
617 		if (ISDOT(p)) {
618 			if (!complained++)
619 				warnx("\".\" and \"..\" may not be removed");
620 			eval = 1;
621 			for (save = t; (t[0] = t[1]) != NULL; ++t)
622 				continue;
623 			t = save;
624 		} else
625 			++t;
626 	}
627 }
628 
629 static void
630 usage(void)
631 {
632 
633 	(void)fprintf(stderr, "%s\n%s\n",
634 	    "usage: rm [-f | -i] [-dIPRrvWx] file ...",
635 	    "       unlink file");
636 	exit(EX_USAGE);
637 }
638 
639 static void
640 siginfo(int sig __unused)
641 {
642 
643 	info = 1;
644 }
645