rm.c revision 27964 
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
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1990, 1993, 1994\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#ifndef lint
41#if 0
42static char sccsid[] = "@(#)rm.c	8.5 (Berkeley) 4/18/94";
43#else
44static const char rcsid[] =
45	"$Id: rm.c,v 1.17 1997/08/07 15:37:47 steve Exp $";
46#endif
47#endif /* not lint */
48
49#include <sys/types.h>
50#include <sys/stat.h>
51
52#include <err.h>
53#include <errno.h>
54#include <fcntl.h>
55#include <fts.h>
56#include <stdio.h>
57#include <stdlib.h>
58#include <string.h>
59#include <unistd.h>
60
61extern char *flags_to_string __P((u_long, char *));
62
63int dflag, eval, fflag, iflag, Pflag, Wflag, stdin_ok;
64uid_t uid;
65
66int	check __P((char *, char *, struct stat *));
67void	checkdot __P((char **));
68void	rm_file __P((char **));
69void	rm_overwrite __P((char *, struct stat *));
70void	rm_tree __P((char **));
71void	usage __P((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(argc, argv)
82	int argc;
83	char *argv[];
84{
85	int ch, rflag;
86
87	Pflag = rflag = 0;
88	while ((ch = getopt(argc, argv, "dfiPRrW")) != -1)
89		switch(ch) {
90		case 'd':
91			dflag = 1;
92			break;
93		case 'f':
94			fflag = 1;
95			iflag = 0;
96			break;
97		case 'i':
98			fflag = 0;
99			iflag = 1;
100			break;
101		case 'P':
102			Pflag = 1;
103			break;
104		case 'R':
105		case 'r':			/* Compatibility. */
106			rflag = 1;
107			break;
108		case 'W':
109			Wflag = 1;
110			break;
111		default:
112			usage();
113		}
114	argc -= optind;
115	argv += optind;
116
117	if (argc < 1)
118		usage();
119
120	checkdot(argv);
121	uid = geteuid();
122
123	if (*argv) {
124		stdin_ok = isatty(STDIN_FILENO);
125
126		if (rflag)
127			rm_tree(argv);
128		else
129			rm_file(argv);
130	}
131
132	exit (eval);
133}
134
135void
136rm_tree(argv)
137	char **argv;
138{
139	FTS *fts;
140	FTSENT *p;
141	int needstat;
142	int flags;
143	int rval;
144
145	/*
146	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
147	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
148	 */
149	needstat = !uid || (!fflag && !iflag && stdin_ok);
150
151	/*
152	 * If the -i option is specified, the user can skip on the pre-order
153	 * visit.  The fts_number field flags skipped directories.
154	 */
155#define	SKIPPED	1
156
157	flags = FTS_PHYSICAL | FTS_NOCHDIR;
158	if (!needstat)
159		flags |= FTS_NOSTAT;
160	if (Wflag)
161		flags |= FTS_WHITEOUT;
162	if (!(fts = fts_open(argv, flags, (int (*)())NULL)))
163		err(1, NULL);
164	while ((p = fts_read(fts)) != NULL) {
165		switch (p->fts_info) {
166		case FTS_DNR:
167			if (!fflag || p->fts_errno != ENOENT) {
168				warnx("%s: %s",
169				    p->fts_path, strerror(p->fts_errno));
170				eval = 1;
171			}
172			continue;
173		case FTS_ERR:
174			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
175		case FTS_NS:
176			/*
177			 * FTS_NS: assume that if can't stat the file, it
178			 * can't be unlinked.
179			 */
180			if (!needstat)
181				break;
182			if (!fflag || p->fts_errno != ENOENT) {
183				warnx("%s: %s",
184				    p->fts_path, strerror(p->fts_errno));
185				eval = 1;
186			}
187			continue;
188		case FTS_D:
189			/* Pre-order: give user chance to skip. */
190			if (!fflag && !check(p->fts_path, p->fts_accpath,
191			    p->fts_statp)) {
192				(void)fts_set(fts, p, FTS_SKIP);
193				p->fts_number = SKIPPED;
194			}
195			else if (!uid &&
196				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
197				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
198				 chflags(p->fts_accpath,
199					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
200				goto err;
201			continue;
202		case FTS_DP:
203			/* Post-order: see if user skipped. */
204			if (p->fts_number == SKIPPED)
205				continue;
206			break;
207		default:
208			if (!fflag &&
209			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
210				continue;
211		}
212
213		rval = 0;
214		if (!uid &&
215		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
216		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
217			rval = chflags(p->fts_accpath,
218				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
219		if (!rval) {
220			/*
221			 * If we can't read or search the directory, may still be
222			 * able to remove it.  Don't print out the un{read,search}able
223			 * message unless the remove fails.
224			 */
225			switch (p->fts_info) {
226			case FTS_DP:
227			case FTS_DNR:
228				if (!rmdir(p->fts_accpath) || (fflag && errno == ENOENT))
229					continue;
230				break;
231
232			case FTS_W:
233				if (!undelete(p->fts_accpath) ||
234			    	(fflag && errno == ENOENT))
235					continue;
236				break;
237
238			default:
239				if (Pflag)
240					rm_overwrite(p->fts_accpath, NULL);
241				if (!unlink(p->fts_accpath) || (fflag && errno == ENOENT))
242					continue;
243			}
244		}
245err:
246		warn("%s", p->fts_path);
247		eval = 1;
248	}
249	if (errno)
250		err(1, "fts_read");
251}
252
253void
254rm_file(argv)
255	char **argv;
256{
257	struct stat sb;
258	int rval;
259	char *f;
260
261	/*
262	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
263	 * to remove a directory is an error, so must always stat the file.
264	 */
265	while ((f = *argv++) != NULL) {
266		/* Assume if can't stat the file, can't unlink it. */
267		if (lstat(f, &sb)) {
268			if (Wflag) {
269				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
270			} else {
271				if (!fflag || errno != ENOENT) {
272					warn("%s", f);
273					eval = 1;
274				}
275				continue;
276			}
277		} else if (Wflag) {
278			warnx("%s: %s", f, strerror(EEXIST));
279			eval = 1;
280			continue;
281		}
282
283		if (S_ISDIR(sb.st_mode) && !dflag) {
284			warnx("%s: is a directory", f);
285			eval = 1;
286			continue;
287		}
288		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
289			continue;
290		rval = 0;
291		if (!uid &&
292		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
293		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
294			rval = chflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
295		if (!rval) {
296			if (S_ISWHT(sb.st_mode))
297				rval = undelete(f);
298			else if (S_ISDIR(sb.st_mode))
299				rval = rmdir(f);
300			else {
301				if (Pflag)
302					rm_overwrite(f, &sb);
303				rval = unlink(f);
304			}
305		}
306		if (rval && (!fflag || errno != ENOENT)) {
307			warn("%s", f);
308			eval = 1;
309		}
310	}
311}
312
313/*
314 * rm_overwrite --
315 *	Overwrite the file 3 times with varying bit patterns.
316 *
317 * XXX
318 * This is a cheap way to *really* delete files.  Note that only regular
319 * files are deleted, directories (and therefore names) will remain.
320 * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
321 * System V file system).  In a logging file system, you'll have to have
322 * kernel support.
323 */
324void
325rm_overwrite(file, sbp)
326	char *file;
327	struct stat *sbp;
328{
329	struct stat sb;
330	off_t len;
331	int fd, wlen;
332	char buf[8 * 1024];
333
334	fd = -1;
335	if (sbp == NULL) {
336		if (lstat(file, &sb))
337			goto err;
338		sbp = &sb;
339	}
340	if (!S_ISREG(sbp->st_mode))
341		return;
342	if ((fd = open(file, O_WRONLY, 0)) == -1)
343		goto err;
344
345#define	PASS(byte) {							\
346	memset(buf, byte, sizeof(buf));					\
347	for (len = sbp->st_size; len > 0; len -= wlen) {		\
348		wlen = len < sizeof(buf) ? len : sizeof(buf);		\
349		if (write(fd, buf, wlen) != wlen)			\
350			goto err;					\
351	}								\
352}
353	PASS(0xff);
354	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
355		goto err;
356	PASS(0x00);
357	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
358		goto err;
359	PASS(0xff);
360	if (!fsync(fd) && !close(fd))
361		return;
362
363err:	eval = 1;
364	warn("%s", file);
365}
366
367
368int
369check(path, name, sp)
370	char *path, *name;
371	struct stat *sp;
372{
373	int ch, first;
374	char modep[15], flagsp[128];
375
376	/* Check -i first. */
377	if (iflag)
378		(void)fprintf(stderr, "remove %s? ", path);
379	else {
380		/*
381		 * If it's not a symbolic link and it's unwritable and we're
382		 * talking to a terminal, ask.  Symbolic links are excluded
383		 * because their permissions are meaningless.  Check stdin_ok
384		 * first because we may not have stat'ed the file.
385		 */
386		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
387		    (!access(name, W_OK) &&
388		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
389		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
390			return (1);
391		strmode(sp->st_mode, modep);
392		strcpy(flagsp, flags_to_string(sp->st_flags, NULL));
393		if (*flagsp)
394			strcat(flagsp, " ");
395		(void)fprintf(stderr, "override %s%s%s/%s %sfor %s? ",
396		    modep + 1, modep[9] == ' ' ? "" : " ",
397		    user_from_uid(sp->st_uid, 0),
398		    group_from_gid(sp->st_gid, 0),
399		    *flagsp ? flagsp : "",
400		    path);
401	}
402	(void)fflush(stderr);
403
404	first = ch = getchar();
405	while (ch != '\n' && ch != EOF)
406		ch = getchar();
407	return (first == 'y' || first == 'Y');
408}
409
410#define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
411void
412checkdot(argv)
413	char **argv;
414{
415	char *p, **save, **t;
416	int complained;
417
418	complained = 0;
419	for (t = argv; *t;) {
420		if ((p = strrchr(*t, '/')) != NULL)
421			++p;
422		else
423			p = *t;
424		if (ISDOT(p)) {
425			if (!complained++)
426				warnx("\".\" and \"..\" may not be removed");
427			eval = 1;
428			for (save = t; (t[0] = t[1]) != NULL; ++t)
429				continue;
430			t = save;
431		} else
432			++t;
433	}
434}
435
436void
437usage()
438{
439
440	(void)fprintf(stderr, "usage: rm [-f | -i] [-dPRrW] file ...\n");
441	exit(1);
442}
443