rm.c revision 127958 
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 127958 2004-04-06 20:06:54Z markm $");
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;
61uid_t uid;
62
63int	check(char *, char *, struct stat *);
64void	checkdot(char **);
65void	rm_file(char **);
66int	rm_overwrite(char *, struct stat *);
67void	rm_tree(char **);
68void	usage(void);
69
70/*
71 * rm --
72 *	This rm is different from historic rm's, but is expected to match
73 *	POSIX 1003.2 behavior.  The most visible difference is that -f
74 *	has two specific effects now, ignore non-existent files and force
75 * 	file removal.
76 */
77int
78main(int argc, char *argv[])
79{
80	int ch, rflag;
81	char *p;
82
83	/*
84	 * Test for the special case where the utility is called as
85	 * "unlink", for which the functionality provided is greatly
86	 * simplified.
87	 */
88	if ((p = rindex(argv[0], '/')) == NULL)
89		p = argv[0];
90	else
91		++p;
92	if (strcmp(p, "unlink") == 0) {
93		while (getopt(argc, argv, "") != -1)
94			usage();
95		argc -= optind;
96		argv += optind;
97		if (argc != 1)
98			usage();
99		rm_file(&argv[0]);
100		exit(eval);
101	}
102
103	Pflag = rflag = 0;
104	while ((ch = getopt(argc, argv, "dfiPRrvW")) != -1)
105		switch(ch) {
106		case 'd':
107			dflag = 1;
108			break;
109		case 'f':
110			fflag = 1;
111			iflag = 0;
112			break;
113		case 'i':
114			fflag = 0;
115			iflag = 1;
116			break;
117		case 'P':
118			Pflag = 1;
119			break;
120		case 'R':
121		case 'r':			/* Compatibility. */
122			rflag = 1;
123			break;
124		case 'v':
125			vflag = 1;
126			break;
127		case 'W':
128			Wflag = 1;
129			break;
130		default:
131			usage();
132		}
133	argc -= optind;
134	argv += optind;
135
136	if (argc < 1) {
137		if (fflag)
138			return (0);
139		usage();
140	}
141
142	checkdot(argv);
143	uid = geteuid();
144
145	if (*argv) {
146		stdin_ok = isatty(STDIN_FILENO);
147
148		if (rflag)
149			rm_tree(argv);
150		else
151			rm_file(argv);
152	}
153
154	exit (eval);
155}
156
157void
158rm_tree(char **argv)
159{
160	FTS *fts;
161	FTSENT *p;
162	int needstat;
163	int flags;
164	int rval;
165
166	/*
167	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
168	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
169	 */
170	needstat = !uid || (!fflag && !iflag && stdin_ok);
171
172	/*
173	 * If the -i option is specified, the user can skip on the pre-order
174	 * visit.  The fts_number field flags skipped directories.
175	 */
176#define	SKIPPED	1
177
178	flags = FTS_PHYSICAL;
179	if (!needstat)
180		flags |= FTS_NOSTAT;
181	if (Wflag)
182		flags |= FTS_WHITEOUT;
183	if (!(fts = fts_open(argv, flags, NULL)))
184		err(1, "fts_open");
185	while ((p = fts_read(fts)) != NULL) {
186		switch (p->fts_info) {
187		case FTS_DNR:
188			if (!fflag || p->fts_errno != ENOENT) {
189				warnx("%s: %s",
190				    p->fts_path, strerror(p->fts_errno));
191				eval = 1;
192			}
193			continue;
194		case FTS_ERR:
195			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
196		case FTS_NS:
197			/*
198			 * Assume that since fts_read() couldn't stat the
199			 * file, it can't be unlinked.
200			 */
201			if (!needstat)
202				break;
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_D:
210			/* Pre-order: give user chance to skip. */
211			if (!fflag && !check(p->fts_path, p->fts_accpath,
212			    p->fts_statp)) {
213				(void)fts_set(fts, p, FTS_SKIP);
214				p->fts_number = SKIPPED;
215			}
216			else if (!uid &&
217				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
218				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
219				 chflags(p->fts_accpath,
220					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
221				goto err;
222			continue;
223		case FTS_DP:
224			/* Post-order: see if user skipped. */
225			if (p->fts_number == SKIPPED)
226				continue;
227			break;
228		default:
229			if (!fflag &&
230			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
231				continue;
232		}
233
234		rval = 0;
235		if (!uid &&
236		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
237		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
238			rval = chflags(p->fts_accpath,
239				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
240		if (rval == 0) {
241			/*
242			 * If we can't read or search the directory, may still be
243			 * able to remove it.  Don't print out the un{read,search}able
244			 * message unless the remove fails.
245			 */
246			switch (p->fts_info) {
247			case FTS_DP:
248			case FTS_DNR:
249				rval = rmdir(p->fts_accpath);
250				if (rval == 0 || (fflag && errno == ENOENT)) {
251					if (rval == 0 && vflag)
252						(void)printf("%s\n",
253						    p->fts_path);
254					continue;
255				}
256				break;
257
258			case FTS_W:
259				rval = undelete(p->fts_accpath);
260				if (rval == 0 && (fflag && errno == ENOENT)) {
261					if (vflag)
262						(void)printf("%s\n",
263						    p->fts_path);
264					continue;
265				}
266				break;
267
268			case FTS_NS:
269				/*
270				 * Assume that since fts_read() couldn't stat
271				 * the file, it can't be unlinked.
272				 */
273				if (fflag)
274					continue;
275				/* FALLTHROUGH */
276			default:
277				if (Pflag)
278					if (!rm_overwrite(p->fts_accpath, NULL))
279						continue;
280				rval = unlink(p->fts_accpath);
281				if (rval == 0 || (fflag && errno == ENOENT)) {
282					if (rval == 0 && vflag)
283						(void)printf("%s\n",
284						    p->fts_path);
285					continue;
286				}
287			}
288		}
289err:
290		warn("%s", p->fts_path);
291		eval = 1;
292	}
293	if (errno)
294		err(1, "fts_read");
295}
296
297void
298rm_file(char **argv)
299{
300	struct stat sb;
301	int rval;
302	char *f;
303
304	/*
305	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
306	 * to remove a directory is an error, so must always stat the file.
307	 */
308	while ((f = *argv++) != NULL) {
309		/* Assume if can't stat the file, can't unlink it. */
310		if (lstat(f, &sb)) {
311			if (Wflag) {
312				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
313			} else {
314				if (!fflag || errno != ENOENT) {
315					warn("%s", f);
316					eval = 1;
317				}
318				continue;
319			}
320		} else if (Wflag) {
321			warnx("%s: %s", f, strerror(EEXIST));
322			eval = 1;
323			continue;
324		}
325
326		if (S_ISDIR(sb.st_mode) && !dflag) {
327			warnx("%s: is a directory", f);
328			eval = 1;
329			continue;
330		}
331		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
332			continue;
333		rval = 0;
334		if (!uid &&
335		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
336		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
337			rval = chflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
338		if (rval == 0) {
339			if (S_ISWHT(sb.st_mode))
340				rval = undelete(f);
341			else if (S_ISDIR(sb.st_mode))
342				rval = rmdir(f);
343			else {
344				if (Pflag)
345					if (!rm_overwrite(f, &sb))
346						continue;
347				rval = unlink(f);
348			}
349		}
350		if (rval && (!fflag || errno != ENOENT)) {
351			warn("%s", f);
352			eval = 1;
353		}
354		if (vflag && rval == 0)
355			(void)printf("%s\n", f);
356	}
357}
358
359/*
360 * rm_overwrite --
361 *	Overwrite the file 3 times with varying bit patterns.
362 *
363 * XXX
364 * This is a cheap way to *really* delete files.  Note that only regular
365 * files are deleted, directories (and therefore names) will remain.
366 * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
367 * System V file system).  In a logging file system, you'll have to have
368 * kernel support.
369 */
370int
371rm_overwrite(char *file, struct stat *sbp)
372{
373	struct stat sb;
374	struct statfs fsb;
375	off_t len;
376	int bsize, fd, wlen;
377	char *buf = NULL;
378
379	fd = -1;
380	if (sbp == NULL) {
381		if (lstat(file, &sb))
382			goto err;
383		sbp = &sb;
384	}
385	if (!S_ISREG(sbp->st_mode))
386		return (1);
387	if ((fd = open(file, O_WRONLY, 0)) == -1)
388		goto err;
389	if (fstatfs(fd, &fsb) == -1)
390		goto err;
391	bsize = MAX(fsb.f_iosize, 1024);
392	if ((buf = malloc(bsize)) == NULL)
393		err(1, "%s: malloc", file);
394
395#define	PASS(byte) {							\
396	memset(buf, byte, bsize);					\
397	for (len = sbp->st_size; len > 0; len -= wlen) {		\
398		wlen = len < bsize ? len : bsize;			\
399		if (write(fd, buf, wlen) != wlen)			\
400			goto err;					\
401	}								\
402}
403	PASS(0xff);
404	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
405		goto err;
406	PASS(0x00);
407	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
408		goto err;
409	PASS(0xff);
410	if (!fsync(fd) && !close(fd)) {
411		free(buf);
412		return (1);
413	}
414
415err:	eval = 1;
416	if (buf)
417		free(buf);
418	if (fd != -1)
419		close(fd);
420	warn("%s", file);
421	return (0);
422}
423
424
425int
426check(char *path, char *name, struct stat *sp)
427{
428	int ch, first;
429	char modep[15], *flagsp;
430
431	/* Check -i first. */
432	if (iflag)
433		(void)fprintf(stderr, "remove %s? ", path);
434	else {
435		/*
436		 * If it's not a symbolic link and it's unwritable and we're
437		 * talking to a terminal, ask.  Symbolic links are excluded
438		 * because their permissions are meaningless.  Check stdin_ok
439		 * first because we may not have stat'ed the file.
440		 * Also skip this check if the -P option was specified because
441		 * we will not be able to overwrite file contents and will
442		 * barf later.
443		 */
444		if (!stdin_ok || S_ISLNK(sp->st_mode) || Pflag ||
445		    (!access(name, W_OK) &&
446		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
447		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
448			return (1);
449		strmode(sp->st_mode, modep);
450		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
451			err(1, "fflagstostr");
452		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
453		    modep + 1, modep[9] == ' ' ? "" : " ",
454		    user_from_uid(sp->st_uid, 0),
455		    group_from_gid(sp->st_gid, 0),
456		    *flagsp ? flagsp : "", *flagsp ? " " : "",
457		    path);
458		free(flagsp);
459	}
460	(void)fflush(stderr);
461
462	first = ch = getchar();
463	while (ch != '\n' && ch != EOF)
464		ch = getchar();
465	return (first == 'y' || first == 'Y');
466}
467
468#define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
469void
470checkdot(char **argv)
471{
472	char *p, **save, **t;
473	int complained;
474
475	complained = 0;
476	for (t = argv; *t;) {
477		if ((p = strrchr(*t, '/')) != NULL)
478			++p;
479		else
480			p = *t;
481		if (ISDOT(p)) {
482			if (!complained++)
483				warnx("\".\" and \"..\" may not be removed");
484			eval = 1;
485			for (save = t; (t[0] = t[1]) != NULL; ++t)
486				continue;
487			t = save;
488		} else
489			++t;
490	}
491}
492
493void
494usage(void)
495{
496
497	(void)fprintf(stderr, "%s\n%s\n",
498	    "usage: rm [-f | -i] [-dPRrvW] file ...",
499	    "       unlink file");
500	exit(EX_USAGE);
501}
502