xref: /freebsd/bin/rm/rm.c (revision 23090366f729c56cab62de74c7a51792357e98a9)
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 <stdint.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <sysexits.h>
59 #include <unistd.h>
60 
61 static int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
62 static int rflag, Iflag;
63 static uid_t uid;
64 static volatile sig_atomic_t info;
65 
66 int	check(char *, char *, struct stat *);
67 int	check2(char **);
68 void	checkdot(char **);
69 void	checkslash(char **);
70 void	rm_file(char **);
71 int	rm_overwrite(char *, struct stat *);
72 void	rm_tree(char **);
73 static void siginfo(int __unused);
74 void	usage(void);
75 
76 /*
77  * rm --
78  *	This rm is different from historic rm's, but is expected to match
79  *	POSIX 1003.2 behavior.	The most visible difference is that -f
80  *	has two specific effects now, ignore non-existent files and force
81  *	file removal.
82  */
83 int
84 main(int argc, char *argv[])
85 {
86 	int ch;
87 	char *p;
88 
89 	/*
90 	 * Test for the special case where the utility is called as
91 	 * "unlink", for which the functionality provided is greatly
92 	 * simplified.
93 	 */
94 	if ((p = strrchr(argv[0], '/')) == NULL)
95 		p = argv[0];
96 	else
97 		++p;
98 	if (strcmp(p, "unlink") == 0) {
99 		while (getopt(argc, argv, "") != -1)
100 			usage();
101 		argc -= optind;
102 		argv += optind;
103 		if (argc != 1)
104 			usage();
105 		rm_file(&argv[0]);
106 		exit(eval);
107 	}
108 
109 	Pflag = rflag = 0;
110 	while ((ch = getopt(argc, argv, "dfiIPRrvW")) != -1)
111 		switch(ch) {
112 		case 'd':
113 			dflag = 1;
114 			break;
115 		case 'f':
116 			fflag = 1;
117 			iflag = 0;
118 			break;
119 		case 'i':
120 			fflag = 0;
121 			iflag = 1;
122 			break;
123 		case 'I':
124 			Iflag = 1;
125 			break;
126 		case 'P':
127 			Pflag = 1;
128 			break;
129 		case 'R':
130 		case 'r':			/* Compatibility. */
131 			rflag = 1;
132 			break;
133 		case 'v':
134 			vflag = 1;
135 			break;
136 		case 'W':
137 			Wflag = 1;
138 			break;
139 		default:
140 			usage();
141 		}
142 	argc -= optind;
143 	argv += optind;
144 
145 	if (argc < 1) {
146 		if (fflag)
147 			return (0);
148 		usage();
149 	}
150 
151 	checkdot(argv);
152 	if (getenv("POSIXLY_CORRECT") == NULL)
153 		checkslash(argv);
154 	uid = geteuid();
155 
156 	(void)signal(SIGINFO, siginfo);
157 	if (*argv) {
158 		stdin_ok = isatty(STDIN_FILENO);
159 
160 		if (Iflag) {
161 			if (check2(argv) == 0)
162 				exit (1);
163 		}
164 		if (rflag)
165 			rm_tree(argv);
166 		else
167 			rm_file(argv);
168 	}
169 
170 	exit (eval);
171 }
172 
173 void
174 rm_tree(char **argv)
175 {
176 	FTS *fts;
177 	FTSENT *p;
178 	int needstat;
179 	int flags;
180 	int rval;
181 
182 	/*
183 	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
184 	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
185 	 */
186 	needstat = !uid || (!fflag && !iflag && stdin_ok);
187 
188 	/*
189 	 * If the -i option is specified, the user can skip on the pre-order
190 	 * visit.  The fts_number field flags skipped directories.
191 	 */
192 #define	SKIPPED	1
193 
194 	flags = FTS_PHYSICAL;
195 	if (!needstat)
196 		flags |= FTS_NOSTAT;
197 	if (Wflag)
198 		flags |= FTS_WHITEOUT;
199 	if (!(fts = fts_open(argv, flags, NULL))) {
200 		if (fflag && errno == ENOENT)
201 			return;
202 		err(1, "fts_open");
203 	}
204 	while ((p = fts_read(fts)) != NULL) {
205 		switch (p->fts_info) {
206 		case FTS_DNR:
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_ERR:
214 			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
215 		case FTS_NS:
216 			/*
217 			 * Assume that since fts_read() couldn't stat the
218 			 * file, it can't be unlinked.
219 			 */
220 			if (!needstat)
221 				break;
222 			if (!fflag || p->fts_errno != ENOENT) {
223 				warnx("%s: %s",
224 				    p->fts_path, strerror(p->fts_errno));
225 				eval = 1;
226 			}
227 			continue;
228 		case FTS_D:
229 			/* Pre-order: give user chance to skip. */
230 			if (!fflag && !check(p->fts_path, p->fts_accpath,
231 			    p->fts_statp)) {
232 				(void)fts_set(fts, p, FTS_SKIP);
233 				p->fts_number = SKIPPED;
234 			}
235 			else if (!uid &&
236 				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
237 				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
238 				 lchflags(p->fts_accpath,
239 					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
240 				goto err;
241 			continue;
242 		case FTS_DP:
243 			/* Post-order: see if user skipped. */
244 			if (p->fts_number == SKIPPED)
245 				continue;
246 			break;
247 		default:
248 			if (!fflag &&
249 			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
250 				continue;
251 		}
252 
253 		rval = 0;
254 		if (!uid &&
255 		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
256 		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
257 			rval = lchflags(p->fts_accpath,
258 				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
259 		if (rval == 0) {
260 			/*
261 			 * If we can't read or search the directory, may still be
262 			 * able to remove it.  Don't print out the un{read,search}able
263 			 * message unless the remove fails.
264 			 */
265 			switch (p->fts_info) {
266 			case FTS_DP:
267 			case FTS_DNR:
268 				rval = rmdir(p->fts_accpath);
269 				if (rval == 0 || (fflag && errno == ENOENT)) {
270 					if (rval == 0 && vflag)
271 						(void)printf("%s\n",
272 						    p->fts_path);
273 					if (rval == 0 && info) {
274 						info = 0;
275 						(void)printf("%s\n",
276 						    p->fts_path);
277 					}
278 					continue;
279 				}
280 				break;
281 
282 			case FTS_W:
283 				rval = undelete(p->fts_accpath);
284 				if (rval == 0 && (fflag && errno == ENOENT)) {
285 					if (vflag)
286 						(void)printf("%s\n",
287 						    p->fts_path);
288 					if (info) {
289 						info = 0;
290 						(void)printf("%s\n",
291 						    p->fts_path);
292 					}
293 					continue;
294 				}
295 				break;
296 
297 			case FTS_NS:
298 				/*
299 				 * Assume that since fts_read() couldn't stat
300 				 * the file, it can't be unlinked.
301 				 */
302 				if (fflag)
303 					continue;
304 				/* FALLTHROUGH */
305 
306 			case FTS_F:
307 			case FTS_NSOK:
308 				if (Pflag)
309 					if (!rm_overwrite(p->fts_accpath, p->fts_info ==
310 					    FTS_NSOK ? NULL : p->fts_statp))
311 						continue;
312 				/* FALLTHROUGH */
313 
314 			default:
315 				rval = unlink(p->fts_accpath);
316 				if (rval == 0 || (fflag && errno == ENOENT)) {
317 					if (rval == 0 && vflag)
318 						(void)printf("%s\n",
319 						    p->fts_path);
320 					if (rval == 0 && info) {
321 						info = 0;
322 						(void)printf("%s\n",
323 						    p->fts_path);
324 					}
325 					continue;
326 				}
327 			}
328 		}
329 err:
330 		warn("%s", p->fts_path);
331 		eval = 1;
332 	}
333 	if (errno)
334 		err(1, "fts_read");
335 	fts_close(fts);
336 }
337 
338 void
339 rm_file(char **argv)
340 {
341 	struct stat sb;
342 	int rval;
343 	char *f;
344 
345 	/*
346 	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
347 	 * to remove a directory is an error, so must always stat the file.
348 	 */
349 	while ((f = *argv++) != NULL) {
350 		/* Assume if can't stat the file, can't unlink it. */
351 		if (lstat(f, &sb)) {
352 			if (Wflag) {
353 				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
354 			} else {
355 				if (!fflag || errno != ENOENT) {
356 					warn("%s", f);
357 					eval = 1;
358 				}
359 				continue;
360 			}
361 		} else if (Wflag) {
362 			warnx("%s: %s", f, strerror(EEXIST));
363 			eval = 1;
364 			continue;
365 		}
366 
367 		if (S_ISDIR(sb.st_mode) && !dflag) {
368 			warnx("%s: is a directory", f);
369 			eval = 1;
370 			continue;
371 		}
372 		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
373 			continue;
374 		rval = 0;
375 		if (!uid && !S_ISWHT(sb.st_mode) &&
376 		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
377 		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
378 			rval = lchflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
379 		if (rval == 0) {
380 			if (S_ISWHT(sb.st_mode))
381 				rval = undelete(f);
382 			else if (S_ISDIR(sb.st_mode))
383 				rval = rmdir(f);
384 			else {
385 				if (Pflag)
386 					if (!rm_overwrite(f, &sb))
387 						continue;
388 				rval = unlink(f);
389 			}
390 		}
391 		if (rval && (!fflag || errno != ENOENT)) {
392 			warn("%s", f);
393 			eval = 1;
394 		}
395 		if (vflag && rval == 0)
396 			(void)printf("%s\n", f);
397 		if (info && rval == 0) {
398 			info = 0;
399 			(void)printf("%s\n", f);
400 		}
401 	}
402 }
403 
404 /*
405  * rm_overwrite --
406  *	Overwrite the file 3 times with varying bit patterns.
407  *
408  * XXX
409  * This is a cheap way to *really* delete files.  Note that only regular
410  * files are deleted, directories (and therefore names) will remain.
411  * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
412  * System V file system).  In a logging or COW file system, you'll have to
413  * have kernel support.
414  */
415 int
416 rm_overwrite(char *file, struct stat *sbp)
417 {
418 	struct stat sb, sb2;
419 	struct statfs fsb;
420 	off_t len;
421 	int bsize, fd, wlen;
422 	char *buf = NULL;
423 
424 	fd = -1;
425 	if (sbp == NULL) {
426 		if (lstat(file, &sb))
427 			goto err;
428 		sbp = &sb;
429 	}
430 	if (!S_ISREG(sbp->st_mode))
431 		return (1);
432 	if (sbp->st_nlink > 1 && !fflag) {
433 		warnx("%s (inode %ju): not overwritten due to multiple links",
434 		    file, (uintmax_t)sbp->st_ino);
435 		return (0);
436 	}
437 	if ((fd = open(file, O_WRONLY|O_NONBLOCK|O_NOFOLLOW, 0)) == -1)
438 		goto err;
439 	if (fstat(fd, &sb2))
440 		goto err;
441 	if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino ||
442 	    !S_ISREG(sb2.st_mode)) {
443 		errno = EPERM;
444 		goto err;
445 	}
446 	if (fstatfs(fd, &fsb) == -1)
447 		goto err;
448 	bsize = MAX(fsb.f_iosize, 1024);
449 	if ((buf = malloc(bsize)) == NULL)
450 		err(1, "%s: malloc", file);
451 
452 #define	PASS(byte) {							\
453 	memset(buf, byte, bsize);					\
454 	for (len = sbp->st_size; len > 0; len -= wlen) {		\
455 		wlen = len < bsize ? len : bsize;			\
456 		if (write(fd, buf, wlen) != wlen)			\
457 			goto err;					\
458 	}								\
459 }
460 	PASS(0xff);
461 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
462 		goto err;
463 	PASS(0x00);
464 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
465 		goto err;
466 	PASS(0xff);
467 	if (!fsync(fd) && !close(fd)) {
468 		free(buf);
469 		return (1);
470 	}
471 
472 err:	eval = 1;
473 	if (buf)
474 		free(buf);
475 	if (fd != -1)
476 		close(fd);
477 	warn("%s", file);
478 	return (0);
479 }
480 
481 
482 int
483 check(char *path, char *name, struct stat *sp)
484 {
485 	int ch, first;
486 	char modep[15], *flagsp;
487 
488 	/* Check -i first. */
489 	if (iflag)
490 		(void)fprintf(stderr, "remove %s? ", path);
491 	else {
492 		/*
493 		 * If it's not a symbolic link and it's unwritable and we're
494 		 * talking to a terminal, ask.	Symbolic links are excluded
495 		 * because their permissions are meaningless.  Check stdin_ok
496 		 * first because we may not have stat'ed the file.
497 		 */
498 		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
499 		    (!access(name, W_OK) &&
500 		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
501 		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
502 			return (1);
503 		strmode(sp->st_mode, modep);
504 		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
505 			err(1, "fflagstostr");
506 		if (Pflag)
507 			errx(1,
508 			    "%s: -P was specified, but file is not writable",
509 			    path);
510 		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
511 		    modep + 1, modep[9] == ' ' ? "" : " ",
512 		    user_from_uid(sp->st_uid, 0),
513 		    group_from_gid(sp->st_gid, 0),
514 		    *flagsp ? flagsp : "", *flagsp ? " " : "",
515 		    path);
516 		free(flagsp);
517 	}
518 	(void)fflush(stderr);
519 
520 	first = ch = getchar();
521 	while (ch != '\n' && ch != EOF)
522 		ch = getchar();
523 	return (first == 'y' || first == 'Y');
524 }
525 
526 #define ISSLASH(a)	((a)[0] == '/' && (a)[1] == '\0')
527 void
528 checkslash(char **argv)
529 {
530 	char **t, **u;
531 	int complained;
532 
533 	complained = 0;
534 	for (t = argv; *t;) {
535 		if (ISSLASH(*t)) {
536 			if (!complained++)
537 				warnx("\"/\" may not be removed");
538 			eval = 1;
539 			for (u = t; u[0] != NULL; ++u)
540 				u[0] = u[1];
541 		} else {
542 			++t;
543 		}
544 	}
545 }
546 
547 int
548 check2(char **argv)
549 {
550 	struct stat st;
551 	int first;
552 	int ch;
553 	int fcount = 0;
554 	int dcount = 0;
555 	int i;
556 	const char *dname = NULL;
557 
558 	for (i = 0; argv[i]; ++i) {
559 		if (lstat(argv[i], &st) == 0) {
560 			if (S_ISDIR(st.st_mode)) {
561 				++dcount;
562 				dname = argv[i];    /* only used if 1 dir */
563 			} else {
564 				++fcount;
565 			}
566 		}
567 	}
568 	first = 0;
569 	while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
570 		if (dcount && rflag) {
571 			fprintf(stderr, "recursively remove");
572 			if (dcount == 1)
573 				fprintf(stderr, " %s", dname);
574 			else
575 				fprintf(stderr, " %d dirs", dcount);
576 			if (fcount == 1)
577 				fprintf(stderr, " and 1 file");
578 			else if (fcount > 1)
579 				fprintf(stderr, " and %d files", fcount);
580 		} else if (dcount + fcount > 3) {
581 			fprintf(stderr, "remove %d files", dcount + fcount);
582 		} else {
583 			return(1);
584 		}
585 		fprintf(stderr, "? ");
586 		fflush(stderr);
587 
588 		first = ch = getchar();
589 		while (ch != '\n' && ch != EOF)
590 			ch = getchar();
591 		if (ch == EOF)
592 			break;
593 	}
594 	return (first == 'y' || first == 'Y');
595 }
596 
597 #define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
598 void
599 checkdot(char **argv)
600 {
601 	char *p, **save, **t;
602 	int complained;
603 
604 	complained = 0;
605 	for (t = argv; *t;) {
606 		if ((p = strrchr(*t, '/')) != NULL)
607 			++p;
608 		else
609 			p = *t;
610 		if (ISDOT(p)) {
611 			if (!complained++)
612 				warnx("\".\" and \"..\" may not be removed");
613 			eval = 1;
614 			for (save = t; (t[0] = t[1]) != NULL; ++t)
615 				continue;
616 			t = save;
617 		} else
618 			++t;
619 	}
620 }
621 
622 void
623 usage(void)
624 {
625 
626 	(void)fprintf(stderr, "%s\n%s\n",
627 	    "usage: rm [-f | -i] [-dIPRrvW] file ...",
628 	    "       unlink file");
629 	exit(EX_USAGE);
630 }
631 
632 static void
633 siginfo(int sig __unused)
634 {
635 
636 	info = 1;
637 }
638