xref: /freebsd/bin/rm/rm.c (revision 7562eaabc01a48e6b11d5b558c41e3b92dae5c2d)
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 int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
61 int rflag, Iflag;
62 uid_t uid;
63 
64 int	check(char *, char *, struct stat *);
65 int	check2(char **);
66 void	checkdot(char **);
67 void	checkslash(char **);
68 void	rm_file(char **);
69 int	rm_overwrite(char *, struct stat *);
70 void	rm_tree(char **);
71 void	usage(void);
72 
73 /*
74  * rm --
75  *	This rm is different from historic rm's, but is expected to match
76  *	POSIX 1003.2 behavior.	The most visible difference is that -f
77  *	has two specific effects now, ignore non-existent files and force
78  *	file removal.
79  */
80 int
81 main(int argc, char *argv[])
82 {
83 	int ch;
84 	char *p;
85 
86 	/*
87 	 * Test for the special case where the utility is called as
88 	 * "unlink", for which the functionality provided is greatly
89 	 * simplified.
90 	 */
91 	if ((p = rindex(argv[0], '/')) == NULL)
92 		p = argv[0];
93 	else
94 		++p;
95 	if (strcmp(p, "unlink") == 0) {
96 		while (getopt(argc, argv, "") != -1)
97 			usage();
98 		argc -= optind;
99 		argv += optind;
100 		if (argc != 1)
101 			usage();
102 		rm_file(&argv[0]);
103 		exit(eval);
104 	}
105 
106 	Pflag = rflag = 0;
107 	while ((ch = getopt(argc, argv, "dfiIPRrvW")) != -1)
108 		switch(ch) {
109 		case 'd':
110 			dflag = 1;
111 			break;
112 		case 'f':
113 			fflag = 1;
114 			iflag = 0;
115 			break;
116 		case 'i':
117 			fflag = 0;
118 			iflag = 1;
119 			break;
120 		case 'I':
121 			Iflag = 1;
122 			break;
123 		case 'P':
124 			Pflag = 1;
125 			break;
126 		case 'R':
127 		case 'r':			/* Compatibility. */
128 			rflag = 1;
129 			break;
130 		case 'v':
131 			vflag = 1;
132 			break;
133 		case 'W':
134 			Wflag = 1;
135 			break;
136 		default:
137 			usage();
138 		}
139 	argc -= optind;
140 	argv += optind;
141 
142 	if (argc < 1) {
143 		if (fflag)
144 			return (0);
145 		usage();
146 	}
147 
148 	checkdot(argv);
149 	if (getenv("POSIXLY_CORRECT") == NULL)
150 		checkslash(argv);
151 	uid = geteuid();
152 
153 	if (*argv) {
154 		stdin_ok = isatty(STDIN_FILENO);
155 
156 		if (Iflag) {
157 			if (check2(argv) == 0)
158 				exit (1);
159 		}
160 		if (rflag)
161 			rm_tree(argv);
162 		else
163 			rm_file(argv);
164 	}
165 
166 	exit (eval);
167 }
168 
169 void
170 rm_tree(char **argv)
171 {
172 	FTS *fts;
173 	FTSENT *p;
174 	int needstat;
175 	int flags;
176 	int rval;
177 
178 	/*
179 	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
180 	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
181 	 */
182 	needstat = !uid || (!fflag && !iflag && stdin_ok);
183 
184 	/*
185 	 * If the -i option is specified, the user can skip on the pre-order
186 	 * visit.  The fts_number field flags skipped directories.
187 	 */
188 #define	SKIPPED	1
189 
190 	flags = FTS_PHYSICAL;
191 	if (!needstat)
192 		flags |= FTS_NOSTAT;
193 	if (Wflag)
194 		flags |= FTS_WHITEOUT;
195 	if (!(fts = fts_open(argv, flags, NULL)))
196 		err(1, "fts_open");
197 	while ((p = fts_read(fts)) != NULL) {
198 		switch (p->fts_info) {
199 		case FTS_DNR:
200 			if (!fflag || p->fts_errno != ENOENT) {
201 				warnx("%s: %s",
202 				    p->fts_path, strerror(p->fts_errno));
203 				eval = 1;
204 			}
205 			continue;
206 		case FTS_ERR:
207 			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
208 		case FTS_NS:
209 			/*
210 			 * Assume that since fts_read() couldn't stat the
211 			 * file, it can't be unlinked.
212 			 */
213 			if (!needstat)
214 				break;
215 			if (!fflag || p->fts_errno != ENOENT) {
216 				warnx("%s: %s",
217 				    p->fts_path, strerror(p->fts_errno));
218 				eval = 1;
219 			}
220 			continue;
221 		case FTS_D:
222 			/* Pre-order: give user chance to skip. */
223 			if (!fflag && !check(p->fts_path, p->fts_accpath,
224 			    p->fts_statp)) {
225 				(void)fts_set(fts, p, FTS_SKIP);
226 				p->fts_number = SKIPPED;
227 			}
228 			else if (!uid &&
229 				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
230 				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
231 				 chflags(p->fts_accpath,
232 					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
233 				goto err;
234 			continue;
235 		case FTS_DP:
236 			/* Post-order: see if user skipped. */
237 			if (p->fts_number == SKIPPED)
238 				continue;
239 			break;
240 		default:
241 			if (!fflag &&
242 			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
243 				continue;
244 		}
245 
246 		rval = 0;
247 		if (!uid &&
248 		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
249 		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
250 			rval = chflags(p->fts_accpath,
251 				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
252 		if (rval == 0) {
253 			/*
254 			 * If we can't read or search the directory, may still be
255 			 * able to remove it.  Don't print out the un{read,search}able
256 			 * message unless the remove fails.
257 			 */
258 			switch (p->fts_info) {
259 			case FTS_DP:
260 			case FTS_DNR:
261 				rval = rmdir(p->fts_accpath);
262 				if (rval == 0 || (fflag && errno == ENOENT)) {
263 					if (rval == 0 && vflag)
264 						(void)printf("%s\n",
265 						    p->fts_path);
266 					continue;
267 				}
268 				break;
269 
270 			case FTS_W:
271 				rval = undelete(p->fts_accpath);
272 				if (rval == 0 && (fflag && errno == ENOENT)) {
273 					if (vflag)
274 						(void)printf("%s\n",
275 						    p->fts_path);
276 					continue;
277 				}
278 				break;
279 
280 			case FTS_NS:
281 				/*
282 				 * Assume that since fts_read() couldn't stat
283 				 * the file, it can't be unlinked.
284 				 */
285 				if (fflag)
286 					continue;
287 				/* FALLTHROUGH */
288 			default:
289 				if (Pflag)
290 					if (!rm_overwrite(p->fts_accpath, NULL))
291 						continue;
292 				rval = unlink(p->fts_accpath);
293 				if (rval == 0 || (fflag && errno == ENOENT)) {
294 					if (rval == 0 && vflag)
295 						(void)printf("%s\n",
296 						    p->fts_path);
297 					continue;
298 				}
299 			}
300 		}
301 err:
302 		warn("%s", p->fts_path);
303 		eval = 1;
304 	}
305 	if (errno)
306 		err(1, "fts_read");
307 }
308 
309 void
310 rm_file(char **argv)
311 {
312 	struct stat sb;
313 	int rval;
314 	char *f;
315 
316 	/*
317 	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
318 	 * to remove a directory is an error, so must always stat the file.
319 	 */
320 	while ((f = *argv++) != NULL) {
321 		/* Assume if can't stat the file, can't unlink it. */
322 		if (lstat(f, &sb)) {
323 			if (Wflag) {
324 				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
325 			} else {
326 				if (!fflag || errno != ENOENT) {
327 					warn("%s", f);
328 					eval = 1;
329 				}
330 				continue;
331 			}
332 		} else if (Wflag) {
333 			warnx("%s: %s", f, strerror(EEXIST));
334 			eval = 1;
335 			continue;
336 		}
337 
338 		if (S_ISDIR(sb.st_mode) && !dflag) {
339 			warnx("%s: is a directory", f);
340 			eval = 1;
341 			continue;
342 		}
343 		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
344 			continue;
345 		rval = 0;
346 		if (!uid &&
347 		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
348 		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
349 			rval = chflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
350 		if (rval == 0) {
351 			if (S_ISWHT(sb.st_mode))
352 				rval = undelete(f);
353 			else if (S_ISDIR(sb.st_mode))
354 				rval = rmdir(f);
355 			else {
356 				if (Pflag)
357 					if (!rm_overwrite(f, &sb))
358 						continue;
359 				rval = unlink(f);
360 			}
361 		}
362 		if (rval && (!fflag || errno != ENOENT)) {
363 			warn("%s", f);
364 			eval = 1;
365 		}
366 		if (vflag && rval == 0)
367 			(void)printf("%s\n", f);
368 	}
369 }
370 
371 /*
372  * rm_overwrite --
373  *	Overwrite the file 3 times with varying bit patterns.
374  *
375  * XXX
376  * This is a cheap way to *really* delete files.  Note that only regular
377  * files are deleted, directories (and therefore names) will remain.
378  * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
379  * System V file system).  In a logging file system, you'll have to have
380  * kernel support.
381  */
382 int
383 rm_overwrite(char *file, struct stat *sbp)
384 {
385 	struct stat sb;
386 	struct statfs fsb;
387 	off_t len;
388 	int bsize, fd, wlen;
389 	char *buf = NULL;
390 
391 	fd = -1;
392 	if (sbp == NULL) {
393 		if (lstat(file, &sb))
394 			goto err;
395 		sbp = &sb;
396 	}
397 	if (!S_ISREG(sbp->st_mode))
398 		return (1);
399 	if ((fd = open(file, O_WRONLY, 0)) == -1)
400 		goto err;
401 	if (fstatfs(fd, &fsb) == -1)
402 		goto err;
403 	bsize = MAX(fsb.f_iosize, 1024);
404 	if ((buf = malloc(bsize)) == NULL)
405 		err(1, "%s: malloc", file);
406 
407 #define	PASS(byte) {							\
408 	memset(buf, byte, bsize);					\
409 	for (len = sbp->st_size; len > 0; len -= wlen) {		\
410 		wlen = len < bsize ? len : bsize;			\
411 		if (write(fd, buf, wlen) != wlen)			\
412 			goto err;					\
413 	}								\
414 }
415 	PASS(0xff);
416 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
417 		goto err;
418 	PASS(0x00);
419 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
420 		goto err;
421 	PASS(0xff);
422 	if (!fsync(fd) && !close(fd)) {
423 		free(buf);
424 		return (1);
425 	}
426 
427 err:	eval = 1;
428 	if (buf)
429 		free(buf);
430 	if (fd != -1)
431 		close(fd);
432 	warn("%s", file);
433 	return (0);
434 }
435 
436 
437 int
438 check(char *path, char *name, struct stat *sp)
439 {
440 	int ch, first;
441 	char modep[15], *flagsp;
442 
443 	/* Check -i first. */
444 	if (iflag)
445 		(void)fprintf(stderr, "remove %s? ", path);
446 	else {
447 		/*
448 		 * If it's not a symbolic link and it's unwritable and we're
449 		 * talking to a terminal, ask.	Symbolic links are excluded
450 		 * because their permissions are meaningless.  Check stdin_ok
451 		 * first because we may not have stat'ed the file.
452 		 * Also skip this check if the -P option was specified because
453 		 * we will not be able to overwrite file contents and will
454 		 * barf later.
455 		 */
456 		if (!stdin_ok || S_ISLNK(sp->st_mode) || Pflag ||
457 		    (!access(name, W_OK) &&
458 		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
459 		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
460 			return (1);
461 		strmode(sp->st_mode, modep);
462 		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
463 			err(1, "fflagstostr");
464 		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
465 		    modep + 1, modep[9] == ' ' ? "" : " ",
466 		    user_from_uid(sp->st_uid, 0),
467 		    group_from_gid(sp->st_gid, 0),
468 		    *flagsp ? flagsp : "", *flagsp ? " " : "",
469 		    path);
470 		free(flagsp);
471 	}
472 	(void)fflush(stderr);
473 
474 	first = ch = getchar();
475 	while (ch != '\n' && ch != EOF)
476 		ch = getchar();
477 	return (first == 'y' || first == 'Y');
478 }
479 
480 #define ISSLASH(a)	((a)[0] == '/' && (a)[1] == '\0')
481 void
482 checkslash(char **argv)
483 {
484 	char **t, **u;
485 	int complained;
486 
487 	complained = 0;
488 	for (t = argv; *t;) {
489 		if (ISSLASH(*t)) {
490 			if (!complained++)
491 				warnx("\"/\" may not be removed");
492 			eval = 1;
493 			for (u = t; u[0] != NULL; ++u)
494 				u[0] = u[1];
495 		} else {
496 			++t;
497 		}
498 	}
499 }
500 
501 int
502 check2(char **argv)
503 {
504 	struct stat st;
505 	int first;
506 	int ch;
507 	int fcount = 0;
508 	int dcount = 0;
509 	int i;
510 	const char *dname = NULL;
511 
512 	for (i = 0; argv[i]; ++i) {
513 		if (lstat(argv[i], &st) == 0) {
514 			if (S_ISDIR(st.st_mode)) {
515 				++dcount;
516 				dname = argv[i];    /* only used if 1 dir */
517 			} else {
518 				++fcount;
519 			}
520 		}
521 	}
522 	first = 0;
523 	while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
524 		if (dcount && rflag) {
525 			fprintf(stderr, "recursively remove");
526 			if (dcount == 1)
527 				fprintf(stderr, " %s", dname);
528 			else
529 				fprintf(stderr, " %d dirs", dcount);
530 			if (fcount == 1)
531 				fprintf(stderr, " and 1 file");
532 			else if (fcount > 1)
533 				fprintf(stderr, " and %d files", fcount);
534 		} else if (dcount + fcount > 3) {
535 			fprintf(stderr, "remove %d files", dcount + fcount);
536 		} else {
537 			return(1);
538 		}
539 		fprintf(stderr, "? ");
540 		fflush(stderr);
541 
542 		first = ch = getchar();
543 		while (ch != '\n' && ch != EOF)
544 			ch = getchar();
545 		if (ch == EOF)
546 			break;
547 	}
548 	return (first == 'y' || first == 'Y');
549 }
550 
551 #define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
552 void
553 checkdot(char **argv)
554 {
555 	char *p, **save, **t;
556 	int complained;
557 
558 	complained = 0;
559 	for (t = argv; *t;) {
560 		if ((p = strrchr(*t, '/')) != NULL)
561 			++p;
562 		else
563 			p = *t;
564 		if (ISDOT(p)) {
565 			if (!complained++)
566 				warnx("\".\" and \"..\" may not be removed");
567 			eval = 1;
568 			for (save = t; (t[0] = t[1]) != NULL; ++t)
569 				continue;
570 			t = save;
571 		} else
572 			++t;
573 	}
574 }
575 
576 void
577 usage(void)
578 {
579 
580 	(void)fprintf(stderr, "%s\n%s\n",
581 	    "usage: rm [-f | -i] [-dIPRrvW] file ...",
582 	    "       unlink file");
583 	exit(EX_USAGE);
584 }
585