rm.c revision 150729 
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
32static 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
38static char sccsid[] = "@(#)rm.c	8.5 (Berkeley) 4/18/94";
39#endif /* not lint */
40#endif
41#include <sys/cdefs.h>
42__FBSDID("$FreeBSD: head/bin/rm/rm.c 150729 2005-09-29 20:40:29Z dougb $");
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
60int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
61int rflag, Iflag;
62uid_t uid;
63
64int	check(char *, char *, struct stat *);
65int	check2(char **);
66void	checkdot(char **);
67void	checkslash(char **);
68void	rm_file(char **);
69int	rm_overwrite(char *, struct stat *);
70void	rm_tree(char **);
71void	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 */
80int
81main(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
169void
170rm_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		if (fflag && errno == ENOENT)
197			return;
198		err(1, "fts_open");
199	}
200	while ((p = fts_read(fts)) != NULL) {
201		switch (p->fts_info) {
202		case FTS_DNR:
203			if (!fflag || p->fts_errno != ENOENT) {
204				warnx("%s: %s",
205				    p->fts_path, strerror(p->fts_errno));
206				eval = 1;
207			}
208			continue;
209		case FTS_ERR:
210			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
211		case FTS_NS:
212			/*
213			 * Assume that since fts_read() couldn't stat the
214			 * file, it can't be unlinked.
215			 */
216			if (!needstat)
217				break;
218			if (!fflag || p->fts_errno != ENOENT) {
219				warnx("%s: %s",
220				    p->fts_path, strerror(p->fts_errno));
221				eval = 1;
222			}
223			continue;
224		case FTS_D:
225			/* Pre-order: give user chance to skip. */
226			if (!fflag && !check(p->fts_path, p->fts_accpath,
227			    p->fts_statp)) {
228				(void)fts_set(fts, p, FTS_SKIP);
229				p->fts_number = SKIPPED;
230			}
231			else if (!uid &&
232				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
233				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
234				 chflags(p->fts_accpath,
235					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
236				goto err;
237			continue;
238		case FTS_DP:
239			/* Post-order: see if user skipped. */
240			if (p->fts_number == SKIPPED)
241				continue;
242			break;
243		default:
244			if (!fflag &&
245			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
246				continue;
247		}
248
249		rval = 0;
250		if (!uid &&
251		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
252		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
253			rval = chflags(p->fts_accpath,
254				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
255		if (rval == 0) {
256			/*
257			 * If we can't read or search the directory, may still be
258			 * able to remove it.  Don't print out the un{read,search}able
259			 * message unless the remove fails.
260			 */
261			switch (p->fts_info) {
262			case FTS_DP:
263			case FTS_DNR:
264				rval = rmdir(p->fts_accpath);
265				if (rval == 0 || (fflag && errno == ENOENT)) {
266					if (rval == 0 && vflag)
267						(void)printf("%s\n",
268						    p->fts_path);
269					continue;
270				}
271				break;
272
273			case FTS_W:
274				rval = undelete(p->fts_accpath);
275				if (rval == 0 && (fflag && errno == ENOENT)) {
276					if (vflag)
277						(void)printf("%s\n",
278						    p->fts_path);
279					continue;
280				}
281				break;
282
283			case FTS_NS:
284				/*
285				 * Assume that since fts_read() couldn't stat
286				 * the file, it can't be unlinked.
287				 */
288				if (fflag)
289					continue;
290				/* FALLTHROUGH */
291			default:
292				if (Pflag)
293					if (!rm_overwrite(p->fts_accpath, NULL))
294						continue;
295				rval = unlink(p->fts_accpath);
296				if (rval == 0 || (fflag && errno == ENOENT)) {
297					if (rval == 0 && vflag)
298						(void)printf("%s\n",
299						    p->fts_path);
300					continue;
301				}
302			}
303		}
304err:
305		warn("%s", p->fts_path);
306		eval = 1;
307	}
308	if (errno)
309		err(1, "fts_read");
310}
311
312void
313rm_file(char **argv)
314{
315	struct stat sb;
316	int rval;
317	char *f;
318
319	/*
320	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
321	 * to remove a directory is an error, so must always stat the file.
322	 */
323	while ((f = *argv++) != NULL) {
324		/* Assume if can't stat the file, can't unlink it. */
325		if (lstat(f, &sb)) {
326			if (Wflag) {
327				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
328			} else {
329				if (!fflag || errno != ENOENT) {
330					warn("%s", f);
331					eval = 1;
332				}
333				continue;
334			}
335		} else if (Wflag) {
336			warnx("%s: %s", f, strerror(EEXIST));
337			eval = 1;
338			continue;
339		}
340
341		if (S_ISDIR(sb.st_mode) && !dflag) {
342			warnx("%s: is a directory", f);
343			eval = 1;
344			continue;
345		}
346		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
347			continue;
348		rval = 0;
349		if (!uid &&
350		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
351		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
352			rval = chflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
353		if (rval == 0) {
354			if (S_ISWHT(sb.st_mode))
355				rval = undelete(f);
356			else if (S_ISDIR(sb.st_mode))
357				rval = rmdir(f);
358			else {
359				if (Pflag)
360					if (!rm_overwrite(f, &sb))
361						continue;
362				rval = unlink(f);
363			}
364		}
365		if (rval && (!fflag || errno != ENOENT)) {
366			warn("%s", f);
367			eval = 1;
368		}
369		if (vflag && rval == 0)
370			(void)printf("%s\n", f);
371	}
372}
373
374/*
375 * rm_overwrite --
376 *	Overwrite the file 3 times with varying bit patterns.
377 *
378 * XXX
379 * This is a cheap way to *really* delete files.  Note that only regular
380 * files are deleted, directories (and therefore names) will remain.
381 * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
382 * System V file system).  In a logging file system, you'll have to have
383 * kernel support.
384 */
385int
386rm_overwrite(char *file, struct stat *sbp)
387{
388	struct stat sb;
389	struct statfs fsb;
390	off_t len;
391	int bsize, fd, wlen;
392	char *buf = NULL;
393
394	fd = -1;
395	if (sbp == NULL) {
396		if (lstat(file, &sb))
397			goto err;
398		sbp = &sb;
399	}
400	if (!S_ISREG(sbp->st_mode))
401		return (1);
402	if ((fd = open(file, O_WRONLY, 0)) == -1)
403		goto err;
404	if (fstatfs(fd, &fsb) == -1)
405		goto err;
406	bsize = MAX(fsb.f_iosize, 1024);
407	if ((buf = malloc(bsize)) == NULL)
408		err(1, "%s: malloc", file);
409
410#define	PASS(byte) {							\
411	memset(buf, byte, bsize);					\
412	for (len = sbp->st_size; len > 0; len -= wlen) {		\
413		wlen = len < bsize ? len : bsize;			\
414		if (write(fd, buf, wlen) != wlen)			\
415			goto err;					\
416	}								\
417}
418	PASS(0xff);
419	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
420		goto err;
421	PASS(0x00);
422	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
423		goto err;
424	PASS(0xff);
425	if (!fsync(fd) && !close(fd)) {
426		free(buf);
427		return (1);
428	}
429
430err:	eval = 1;
431	if (buf)
432		free(buf);
433	if (fd != -1)
434		close(fd);
435	warn("%s", file);
436	return (0);
437}
438
439
440int
441check(char *path, char *name, struct stat *sp)
442{
443	int ch, first;
444	char modep[15], *flagsp;
445
446	/* Check -i first. */
447	if (iflag)
448		(void)fprintf(stderr, "remove %s? ", path);
449	else {
450		/*
451		 * If it's not a symbolic link and it's unwritable and we're
452		 * talking to a terminal, ask.	Symbolic links are excluded
453		 * because their permissions are meaningless.  Check stdin_ok
454		 * first because we may not have stat'ed the file.
455		 */
456		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
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		if (Pflag)
465			errx(1,
466			    "%s: -P was specified, but file is not writable",
467			    path);
468		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
469		    modep + 1, modep[9] == ' ' ? "" : " ",
470		    user_from_uid(sp->st_uid, 0),
471		    group_from_gid(sp->st_gid, 0),
472		    *flagsp ? flagsp : "", *flagsp ? " " : "",
473		    path);
474		free(flagsp);
475	}
476	(void)fflush(stderr);
477
478	first = ch = getchar();
479	while (ch != '\n' && ch != EOF)
480		ch = getchar();
481	return (first == 'y' || first == 'Y');
482}
483
484#define ISSLASH(a)	((a)[0] == '/' && (a)[1] == '\0')
485void
486checkslash(char **argv)
487{
488	char **t, **u;
489	int complained;
490
491	complained = 0;
492	for (t = argv; *t;) {
493		if (ISSLASH(*t)) {
494			if (!complained++)
495				warnx("\"/\" may not be removed");
496			eval = 1;
497			for (u = t; u[0] != NULL; ++u)
498				u[0] = u[1];
499		} else {
500			++t;
501		}
502	}
503}
504
505int
506check2(char **argv)
507{
508	struct stat st;
509	int first;
510	int ch;
511	int fcount = 0;
512	int dcount = 0;
513	int i;
514	const char *dname = NULL;
515
516	for (i = 0; argv[i]; ++i) {
517		if (lstat(argv[i], &st) == 0) {
518			if (S_ISDIR(st.st_mode)) {
519				++dcount;
520				dname = argv[i];    /* only used if 1 dir */
521			} else {
522				++fcount;
523			}
524		}
525	}
526	first = 0;
527	while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
528		if (dcount && rflag) {
529			fprintf(stderr, "recursively remove");
530			if (dcount == 1)
531				fprintf(stderr, " %s", dname);
532			else
533				fprintf(stderr, " %d dirs", dcount);
534			if (fcount == 1)
535				fprintf(stderr, " and 1 file");
536			else if (fcount > 1)
537				fprintf(stderr, " and %d files", fcount);
538		} else if (dcount + fcount > 3) {
539			fprintf(stderr, "remove %d files", dcount + fcount);
540		} else {
541			return(1);
542		}
543		fprintf(stderr, "? ");
544		fflush(stderr);
545
546		first = ch = getchar();
547		while (ch != '\n' && ch != EOF)
548			ch = getchar();
549		if (ch == EOF)
550			break;
551	}
552	return (first == 'y' || first == 'Y');
553}
554
555#define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
556void
557checkdot(char **argv)
558{
559	char *p, **save, **t;
560	int complained;
561
562	complained = 0;
563	for (t = argv; *t;) {
564		if ((p = strrchr(*t, '/')) != NULL)
565			++p;
566		else
567			p = *t;
568		if (ISDOT(p)) {
569			if (!complained++)
570				warnx("\".\" and \"..\" may not be removed");
571			eval = 1;
572			for (save = t; (t[0] = t[1]) != NULL; ++t)
573				continue;
574			t = save;
575		} else
576			++t;
577	}
578}
579
580void
581usage(void)
582{
583
584	(void)fprintf(stderr, "%s\n%s\n",
585	    "usage: rm [-f | -i] [-dIPRrvW] file ...",
586	    "       unlink file");
587	exit(EX_USAGE);
588}
589