xref: /dragonfly/bin/rm/rm.c (revision 19fe1c42)
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  * @(#) Copyright (c) 1990, 1993, 1994 The Regents of the University of California.  All rights reserved.
34  * @(#)rm.c	8.5 (Berkeley) 4/18/94
35  * $FreeBSD: src/bin/rm/rm.c,v 1.29.2.5 2002/07/12 07:25:48 tjr Exp $
36  * $DragonFly: src/bin/rm/rm.c,v 1.19 2006/11/12 00:51:47 swildner Exp $
37  */
38 
39 #include <sys/stat.h>
40 #include <sys/param.h>
41 #include <sys/mount.h>
42 #include <sys/ioctl.h>
43 
44 #include <err.h>
45 #include <errno.h>
46 #include <fcntl.h>
47 #include <fts.h>
48 #include <grp.h>
49 #include <pwd.h>
50 #include <signal.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <sysexits.h>
55 #include <unistd.h>
56 
57 static int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
58 static int rflag, Iflag;
59 static uid_t uid;
60 volatile sig_atomic_t info;
61 
62 static int	check(const char *, const char *, struct stat *);
63 static int	check2(char **);
64 static void	checkdot(char **);
65 static void	rm_file(char **);
66 static int	rm_overwrite(const char *, struct stat *);
67 static void	rm_tree(char **);
68 static void 	siginfo(int);
69 static void	usage(void);
70 
71 /*
72  * rm --
73  *	This rm is different from historic rm's, but is expected to match
74  *	POSIX 1003.2 behavior.  The most visible difference is that -f
75  *	has two specific effects now, ignore non-existent files and force
76  * 	file removal.
77  */
78 int
79 main(int argc, char *argv[])
80 {
81 	int ch;
82 	const char *p;
83 	pid_t tty_pgrp;
84 
85 	/*
86 	 * Test for the special case where the utility is called as
87 	 * "unlink", for which the functionality provided is greatly
88 	 * simplified.
89 	 */
90 	if ((p = strrchr(argv[0], '/')) == NULL)
91 		p = argv[0];
92 	else
93 		++p;
94 	if (strcmp(p, "unlink") == 0) {
95 		while (getopt(argc, argv, "") != -1)
96 			usage();
97 		argc -= optind;
98 		argv += optind;
99 		if (argc != 1)
100 			usage();
101 		rm_file(&argv[0]);
102 		exit(eval);
103 	}
104 
105 	Pflag = rflag = 0;
106 	while ((ch = getopt(argc, argv, "dfiIPRrvW")) != -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 'I':
120 			/*
121 			 * The -I flag is intended to be generally aliasable
122 			 * in /etc/csh.cshrc.  We apply it only to foreground
123 			 * processes.
124 			 */
125 			if (ioctl(0, TIOCGPGRP, &tty_pgrp) == 0) {
126 				if (tty_pgrp == getpgrp())
127 					Iflag = 1;
128 			}
129 			break;
130 		case 'P':
131 			Pflag = 1;
132 			break;
133 		case 'R':
134 		case 'r':			/* Compatibility. */
135 			rflag = 1;
136 			break;
137 		case 'v':
138 			vflag = 1;
139 			break;
140 		case 'W':
141 			Wflag = 1;
142 			break;
143 		default:
144 			usage();
145 		}
146 	}
147 	argc -= optind;
148 	argv += optind;
149 
150 	if (argc < 1) {
151 		if (fflag)
152 			return 0;
153 		usage();
154 	}
155 
156 	checkdot(argv);
157 	uid = geteuid();
158 
159 	signal(SIGINFO, siginfo);
160 
161 	if (*argv) {
162 		stdin_ok = isatty(STDIN_FILENO);
163 
164 		if (Iflag && !iflag) {
165 			if (check2(argv) == 0)
166 				exit (1);
167 		}
168 		if (rflag)
169 			rm_tree(argv);
170 		else
171 			rm_file(argv);
172 	}
173 
174 	exit (eval);
175 }
176 
177 static void
178 rm_tree(char **argv)
179 {
180 	FTS *fts;
181 	FTSENT *p;
182 	int needstat;
183 	int flags;
184 	int rval;
185 
186 	/*
187 	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
188 	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
189 	 */
190 	needstat = !uid || (!fflag && !iflag && stdin_ok);
191 
192 	/*
193 	 * If the -i option is specified, the user can skip on the pre-order
194 	 * visit.  The fts_number field flags skipped directories.
195 	 */
196 #define	SKIPPED	1
197 
198 	flags = FTS_PHYSICAL;
199 	if (!needstat)
200 		flags |= FTS_NOSTAT;
201 	if (Wflag)
202 		flags |= FTS_WHITEOUT;
203 	if ((fts = fts_open(argv, flags, NULL)) == NULL) {
204 		if (fflag && errno == ENOENT)
205 			return;
206 		err(1, NULL);
207 	}
208 	while ((p = fts_read(fts)) != NULL) {
209 		switch (p->fts_info) {
210 		case FTS_DNR:
211 			if (!fflag || p->fts_errno != ENOENT) {
212 				warnx("%s: %s",
213 				    p->fts_path, strerror(p->fts_errno));
214 				eval = 1;
215 			}
216 			continue;
217 		case FTS_ERR:
218 			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
219 		case FTS_NS:
220 		       /*
221 			* Assume that since fts_read() couldn't stat
222 			* the file, it can't be unlinked.
223 			*/
224 			if (!needstat)
225 				break;
226 			if (!fflag || p->fts_errno != ENOENT) {
227 				warnx("%s: %s",
228 				    p->fts_path, strerror(p->fts_errno));
229 				eval = 1;
230 			}
231 			continue;
232 		case FTS_D:
233 			/* Pre-order: give user chance to skip. */
234 			if (!fflag && !check(p->fts_path, p->fts_accpath,
235 			    p->fts_statp)) {
236 				fts_set(fts, p, FTS_SKIP);
237 				p->fts_number = SKIPPED;
238 			}
239 			else if (!uid &&
240 				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
241 				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
242 				 chflags(p->fts_accpath,
243 					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
244 				goto err;
245 			continue;
246 		case FTS_DP:
247 			/* Post-order: see if user skipped. */
248 			if (p->fts_number == SKIPPED)
249 				continue;
250 			break;
251 		default:
252 			if (!fflag &&
253 			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
254 				continue;
255 		}
256 
257 		if (info) {
258 			info = 0;
259 			fprintf(stderr, "Currently removing: %s\n", p->fts_path);
260 		}
261 
262 		rval = 0;
263 		if (!uid &&
264 		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
265 		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
266 			rval = chflags(p->fts_accpath,
267 				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
268 
269 		if (rval == 0) {
270 			/*
271 			 * If we can't read or search the directory, may still be
272 			 * able to remove it.  Don't print out the un{read,search}able
273 			 * message unless the remove fails.
274 			 */
275 			switch (p->fts_info) {
276 			case FTS_DP:
277 			case FTS_DNR:
278 				rval = rmdir(p->fts_accpath);
279 				if (rval == 0 || (fflag && errno == ENOENT)) {
280 					if (rval == 0 && vflag)
281 						printf("%s\n",
282 						    p->fts_path);
283 					continue;
284 				}
285 				break;
286 
287 			case FTS_W:
288 				rval = undelete(p->fts_accpath);
289 				if (rval == 0 && (fflag && errno == ENOENT)) {
290 					if (vflag)
291 						printf("%s\n",
292 						    p->fts_path);
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 			default:
306 				if (Pflag)
307 					if (!rm_overwrite(p->fts_accpath, NULL))
308 						continue;
309 				rval = unlink(p->fts_accpath);
310 				if (rval == 0 || (fflag && errno == ENOENT)) {
311 					if (rval == 0 && vflag)
312 						printf("%s\n",
313 						    p->fts_path);
314 					continue;
315 				}
316 			}
317 		}
318 err:
319 		warn("%s", p->fts_path);
320 		eval = 1;
321 	}
322 	if (errno)
323 		err(1, "fts_read");
324 	fts_close(fts);
325 }
326 
327 static void
328 rm_file(char **argv)
329 {
330 	struct stat sb;
331 	int rval;
332 	const char *f;
333 
334 	/*
335 	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
336 	 * to remove a directory is an error, so must always stat the file.
337 	 */
338 	while ((f = *argv++) != NULL) {
339 		if (info) {
340 			info = 0;
341 			fprintf(stderr, "Currently removing: %s\n", f);
342 		}
343 
344 		/* Assume if can't stat the file, can't unlink it. */
345 		if (lstat(f, &sb)) {
346 			if (Wflag) {
347 				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
348 			} else {
349 				if (!fflag || errno != ENOENT) {
350 					warn("%s", f);
351 					eval = 1;
352 				}
353 				continue;
354 			}
355 		} else if (Wflag) {
356 			warnx("%s: %s", f, strerror(EEXIST));
357 			eval = 1;
358 			continue;
359 		}
360 
361 		if (S_ISDIR(sb.st_mode) && !dflag) {
362 			warnx("%s: is a directory", f);
363 			eval = 1;
364 			continue;
365 		}
366 		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
367 			continue;
368 		rval = 0;
369 		if (!uid &&
370 		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
371 		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
372 			rval = chflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
373 		if (rval == 0) {
374 			if (S_ISWHT(sb.st_mode))
375 				rval = undelete(f);
376 			else if (S_ISDIR(sb.st_mode))
377 				rval = rmdir(f);
378 			else {
379 				if (Pflag)
380 					if (!rm_overwrite(f, &sb))
381 						continue;
382 				rval = unlink(f);
383 			}
384 		}
385 		if (rval && (!fflag || errno != ENOENT)) {
386 			warn("%s", f);
387 			eval = 1;
388 		}
389 		if (vflag && rval == 0)
390 			printf("%s\n", f);
391 	}
392 }
393 
394 /*
395  * rm_overwrite --
396  *	Overwrite the file 3 times with varying bit patterns.
397  *
398  * XXX
399  * This is a cheap way to *really* delete files.  Note that only regular
400  * files are deleted, directories (and therefore names) will remain.
401  * Also, this assumes a fixed-block filesystem (like FFS, or a V7 or a
402  * System V filesystem).  In a logging filesystem, you'll have to have
403  * kernel support.
404  */
405 static int
406 rm_overwrite(const char *file, struct stat *sbp)
407 {
408 	struct stat sb;
409 	struct statfs fsb;
410 	off_t len;
411 	int bsize, fd, wlen;
412 	char *buf = NULL;
413 
414 	fd = -1;
415 	if (sbp == NULL) {
416 		if (lstat(file, &sb))
417 			goto err;
418 		sbp = &sb;
419 	}
420 	if (!S_ISREG(sbp->st_mode)) {
421 		warnx("%s: cannot overwrite a non-regular file", file);
422 		return (1);
423 	}
424 	if (sbp->st_nlink > 1) {
425 		warnx("%s (inode %ju): not overwritten due to multiple links",
426 		      file, (uintmax_t)sbp->st_ino);
427 		return (0);
428 	}
429 	if ((fd = open(file, O_WRONLY, 0)) == -1)
430 		goto err;
431 	if (fstatfs(fd, &fsb) == -1)
432 		goto err;
433 	bsize = MAX(fsb.f_iosize, 1024);
434 	if ((buf = malloc(bsize)) == NULL)
435 		err(1, "%s malloc failed", file);
436 
437 #define	PASS(byte) {							\
438 	memset(buf, byte, bsize);					\
439 	for (len = sbp->st_size; len > 0; len -= wlen) {		\
440 		wlen = len < bsize ? len : bsize;			\
441 		if (write(fd, buf, wlen) != wlen)			\
442 			goto err;					\
443 	}								\
444 }
445 	PASS(0xff);
446 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
447 		goto err;
448 	PASS(0x00);
449 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
450 		goto err;
451 	PASS(0xff);
452 	if (!fsync(fd) && !close(fd)) {
453 		free(buf);
454 		return (1);
455 	}
456 
457 err:	eval = 1;
458 	if (buf)
459 		free(buf);
460 	if (fd != -1)
461 		close(fd);
462 	warn("%s", file);
463 	return (0);
464 }
465 
466 
467 static int
468 check(const char *path, const char *name, struct stat *sp)
469 {
470 	static int perm_answer = -1;
471 	struct choice {
472 		int ch;
473 		const char *str;
474 		int res;
475 		int perm;
476 	} *choice, choices[] = {
477 		{ 'y', "yes"   , 1, 0 },
478 		{ 'n', "no"    , 0, 0 },
479 		{ 'a', "always", 1, 1 },
480 		{ 'v', "never" , 0, 1 },
481 		{ 0, NULL, 0, 0 }
482 	};
483 	char modep[15], *flagsp;
484 
485 	if (perm_answer != -1)
486 		return (perm_answer);
487 
488 	/* Check -i first. */
489 	if (iflag)
490 		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 		 * Also skip this check if the -P option was specified because
498 	         * we will not be able to overwrite file contents and will
499 	         * barf later.
500 		 */
501 		if (!stdin_ok || S_ISLNK(sp->st_mode) || Pflag ||
502 		    (!access(name, W_OK) &&
503 		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
504 		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
505 			return (1);
506 		strmode(sp->st_mode, modep);
507 		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
508 			err(1, NULL);
509 		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 	fflush(stderr);
518 
519 	for (;;) {
520 		size_t len;
521 		char *answer;
522 
523 		answer = fgetln(stdin, &len);
524 		/* clearerr(stdin); */
525 		if (answer == NULL)
526 			return (0);
527 		if (answer[len - 1] == '\n')
528 			len--;
529 		if (len == 0)
530 			continue;
531 
532 		for (choice = choices; choice->str != NULL; choice++) {
533 			if (len == 1 && choice->ch == answer[0])
534 				goto valid_choice;
535 			if (strncasecmp(answer, choice->str, len) == 0)
536 				goto valid_choice;
537 		}
538 
539 		fprintf(stderr, "invalid answer, try again (y/n/a/v): ");
540 	}
541 
542 valid_choice:
543 	if (choice->perm)
544 		perm_answer = choice->res;
545 	return (choice->res);
546 }
547 
548 static int
549 check2(char **argv)
550 {
551 	struct stat st;
552 	int first;
553 	int ch;
554 	int fcount = 0;
555 	int dcount = 0;
556 	int i;
557 	const char *dname = NULL;
558 
559 	for (i = 0; argv[i]; ++i) {
560 		if (lstat(argv[i], &st) == 0) {
561 			if (S_ISDIR(st.st_mode)) {
562 				++dcount;
563 				dname = argv[i];    /* only used if 1 dir */
564 			} else {
565 				++fcount;
566 			}
567 		}
568 	}
569 	first = 0;
570 	while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
571 		if (dcount && rflag) {
572 			fprintf(stderr, "recursively remove");
573 			if (dcount == 1)
574 				fprintf(stderr, " %s", dname);
575 			else
576 				fprintf(stderr, " %d dirs", dcount);
577 			if (fcount == 1)
578 				fprintf(stderr, " and 1 file");
579 			else if (fcount > 1)
580 				fprintf(stderr, " and %d files", fcount);
581 		} else if (dcount + fcount > 3) {
582 			fprintf(stderr, "remove %d files", dcount + fcount);
583 		} else {
584 			return(1);
585 		}
586 		fprintf(stderr, "? ");
587 		fflush(stderr);
588 
589 		first = ch = getchar();
590 		while (ch != '\n' && ch != EOF)
591 			ch = getchar();
592 		if (ch == EOF)
593 			break;
594 	}
595 	return (first == 'y' || first == 'Y');
596 }
597 
598 #define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
599 static void
600 checkdot(char **argv)
601 {
602 	char *p, **save, **t;
603 	int complained;
604 
605 	complained = 0;
606 	for (t = argv; *t;) {
607 		if ((p = strrchr(*t, '/')) != NULL)
608 			++p;
609 		else
610 			p = *t;
611 		if (ISDOT(p)) {
612 			if (!complained++)
613 				warnx("\".\" and \"..\" may not be removed");
614 			eval = 1;
615 			for (save = t; (t[0] = t[1]) != NULL; ++t)
616 				continue;
617 			t = save;
618 		} else
619 			++t;
620 	}
621 }
622 
623 static void
624 usage(void)
625 {
626 
627 	fprintf(stderr, "%s\n%s\n",
628 	    "usage: rm [-f | -i] [-dIPRrvW] file ...",
629 	    "       unlink file");
630 	exit(EX_USAGE);
631 }
632 
633 static void
634 siginfo(int notused __unused)
635 {
636 	info = 1;
637 }
638