rm.c revision 331722 
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: stable/11/bin/rm/rm.c 331722 2018-03-29 02:50:57Z eadler $");
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 <locale.h>
54#include <pwd.h>
55#include <stdint.h>
56#include <stdio.h>
57#include <stdlib.h>
58#include <string.h>
59#include <sysexits.h>
60#include <unistd.h>
61
62static int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
63static int rflag, Iflag, xflag;
64static uid_t uid;
65static volatile sig_atomic_t info;
66
67static int	check(const char *, const char *, struct stat *);
68static int	check2(char **);
69static void	checkdot(char **);
70static void	checkslash(char **);
71static void	rm_file(char **);
72static int	rm_overwrite(const char *, struct stat *);
73static void	rm_tree(char **);
74static void siginfo(int __unused);
75static void	usage(void);
76
77/*
78 * rm --
79 *	This rm is different from historic rm's, but is expected to match
80 *	POSIX 1003.2 behavior.	The most visible difference is that -f
81 *	has two specific effects now, ignore non-existent files and force
82 *	file removal.
83 */
84int
85main(int argc, char *argv[])
86{
87	int ch;
88	char *p;
89
90	(void)setlocale(LC_ALL, "");
91
92	/*
93	 * Test for the special case where the utility is called as
94	 * "unlink", for which the functionality provided is greatly
95	 * simplified.
96	 */
97	if ((p = strrchr(argv[0], '/')) == NULL)
98		p = argv[0];
99	else
100		++p;
101	if (strcmp(p, "unlink") == 0) {
102		while (getopt(argc, argv, "") != -1)
103			usage();
104		argc -= optind;
105		argv += optind;
106		if (argc != 1)
107			usage();
108		rm_file(&argv[0]);
109		exit(eval);
110	}
111
112	Pflag = rflag = xflag = 0;
113	while ((ch = getopt(argc, argv, "dfiIPRrvWx")) != -1)
114		switch(ch) {
115		case 'd':
116			dflag = 1;
117			break;
118		case 'f':
119			fflag = 1;
120			iflag = 0;
121			break;
122		case 'i':
123			fflag = 0;
124			iflag = 1;
125			break;
126		case 'I':
127			Iflag = 1;
128			break;
129		case 'P':
130			Pflag = 1;
131			break;
132		case 'R':
133		case 'r':			/* Compatibility. */
134			rflag = 1;
135			break;
136		case 'v':
137			vflag = 1;
138			break;
139		case 'W':
140			Wflag = 1;
141			break;
142		case 'x':
143			xflag = 1;
144			break;
145		default:
146			usage();
147		}
148	argc -= optind;
149	argv += optind;
150
151	if (argc < 1) {
152		if (fflag)
153			return (0);
154		usage();
155	}
156
157	checkdot(argv);
158	checkslash(argv);
159	uid = geteuid();
160
161	(void)signal(SIGINFO, siginfo);
162	if (*argv) {
163		stdin_ok = isatty(STDIN_FILENO);
164
165		if (Iflag) {
166			if (check2(argv) == 0)
167				exit (1);
168		}
169		if (rflag)
170			rm_tree(argv);
171		else
172			rm_file(argv);
173	}
174
175	exit (eval);
176}
177
178static void
179rm_tree(char **argv)
180{
181	FTS *fts;
182	FTSENT *p;
183	int needstat;
184	int flags;
185	int rval;
186
187	/*
188	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
189	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
190	 */
191	needstat = !uid || (!fflag && !iflag && stdin_ok);
192
193	/*
194	 * If the -i option is specified, the user can skip on the pre-order
195	 * visit.  The fts_number field flags skipped directories.
196	 */
197#define	SKIPPED	1
198
199	flags = FTS_PHYSICAL;
200	if (!needstat)
201		flags |= FTS_NOSTAT;
202	if (Wflag)
203		flags |= FTS_WHITEOUT;
204	if (xflag)
205		flags |= FTS_XDEV;
206	if (!(fts = fts_open(argv, flags, NULL))) {
207		if (fflag && errno == ENOENT)
208			return;
209		err(1, "fts_open");
210	}
211	while ((p = fts_read(fts)) != NULL) {
212		switch (p->fts_info) {
213		case FTS_DNR:
214			if (!fflag || p->fts_errno != ENOENT) {
215				warnx("%s: %s",
216				    p->fts_path, strerror(p->fts_errno));
217				eval = 1;
218			}
219			continue;
220		case FTS_ERR:
221			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
222		case FTS_NS:
223			/*
224			 * Assume that since fts_read() couldn't stat the
225			 * file, it can't be unlinked.
226			 */
227			if (!needstat)
228				break;
229			if (!fflag || p->fts_errno != ENOENT) {
230				warnx("%s: %s",
231				    p->fts_path, strerror(p->fts_errno));
232				eval = 1;
233			}
234			continue;
235		case FTS_D:
236			/* Pre-order: give user chance to skip. */
237			if (!fflag && !check(p->fts_path, p->fts_accpath,
238			    p->fts_statp)) {
239				(void)fts_set(fts, p, FTS_SKIP);
240				p->fts_number = SKIPPED;
241			}
242			else if (!uid &&
243				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
244				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
245				 lchflags(p->fts_accpath,
246					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
247				goto err;
248			continue;
249		case FTS_DP:
250			/* Post-order: see if user skipped. */
251			if (p->fts_number == SKIPPED)
252				continue;
253			break;
254		default:
255			if (!fflag &&
256			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
257				continue;
258		}
259
260		rval = 0;
261		if (!uid &&
262		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
263		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
264			rval = lchflags(p->fts_accpath,
265				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
266		if (rval == 0) {
267			/*
268			 * If we can't read or search the directory, may still be
269			 * able to remove it.  Don't print out the un{read,search}able
270			 * message unless the remove fails.
271			 */
272			switch (p->fts_info) {
273			case FTS_DP:
274			case FTS_DNR:
275				rval = rmdir(p->fts_accpath);
276				if (rval == 0 || (fflag && errno == ENOENT)) {
277					if (rval == 0 && vflag)
278						(void)printf("%s\n",
279						    p->fts_path);
280					if (rval == 0 && info) {
281						info = 0;
282						(void)printf("%s\n",
283						    p->fts_path);
284					}
285					continue;
286				}
287				break;
288
289			case FTS_W:
290				rval = undelete(p->fts_accpath);
291				if (rval == 0 && (fflag && errno == ENOENT)) {
292					if (vflag)
293						(void)printf("%s\n",
294						    p->fts_path);
295					if (info) {
296						info = 0;
297						(void)printf("%s\n",
298						    p->fts_path);
299					}
300					continue;
301				}
302				break;
303
304			case FTS_NS:
305				/*
306				 * Assume that since fts_read() couldn't stat
307				 * the file, it can't be unlinked.
308				 */
309				if (fflag)
310					continue;
311				/* FALLTHROUGH */
312
313			case FTS_F:
314			case FTS_NSOK:
315				if (Pflag)
316					if (!rm_overwrite(p->fts_accpath, p->fts_info ==
317					    FTS_NSOK ? NULL : p->fts_statp))
318						continue;
319				/* FALLTHROUGH */
320
321			default:
322				rval = unlink(p->fts_accpath);
323				if (rval == 0 || (fflag && errno == ENOENT)) {
324					if (rval == 0 && vflag)
325						(void)printf("%s\n",
326						    p->fts_path);
327					if (rval == 0 && info) {
328						info = 0;
329						(void)printf("%s\n",
330						    p->fts_path);
331					}
332					continue;
333				}
334			}
335		}
336err:
337		warn("%s", p->fts_path);
338		eval = 1;
339	}
340	if (!fflag && errno)
341		err(1, "fts_read");
342	fts_close(fts);
343}
344
345static void
346rm_file(char **argv)
347{
348	struct stat sb;
349	int rval;
350	char *f;
351
352	/*
353	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
354	 * to remove a directory is an error, so must always stat the file.
355	 */
356	while ((f = *argv++) != NULL) {
357		/* Assume if can't stat the file, can't unlink it. */
358		if (lstat(f, &sb)) {
359			if (Wflag) {
360				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
361			} else {
362				if (!fflag || errno != ENOENT) {
363					warn("%s", f);
364					eval = 1;
365				}
366				continue;
367			}
368		} else if (Wflag) {
369			warnx("%s: %s", f, strerror(EEXIST));
370			eval = 1;
371			continue;
372		}
373
374		if (S_ISDIR(sb.st_mode) && !dflag) {
375			warnx("%s: is a directory", f);
376			eval = 1;
377			continue;
378		}
379		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
380			continue;
381		rval = 0;
382		if (!uid && !S_ISWHT(sb.st_mode) &&
383		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
384		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
385			rval = lchflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
386		if (rval == 0) {
387			if (S_ISWHT(sb.st_mode))
388				rval = undelete(f);
389			else if (S_ISDIR(sb.st_mode))
390				rval = rmdir(f);
391			else {
392				if (Pflag)
393					if (!rm_overwrite(f, &sb))
394						continue;
395				rval = unlink(f);
396			}
397		}
398		if (rval && (!fflag || errno != ENOENT)) {
399			warn("%s", f);
400			eval = 1;
401		}
402		if (vflag && rval == 0)
403			(void)printf("%s\n", f);
404		if (info && rval == 0) {
405			info = 0;
406			(void)printf("%s\n", f);
407		}
408	}
409}
410
411/*
412 * rm_overwrite --
413 *	Overwrite the file 3 times with varying bit patterns.
414 *
415 * XXX
416 * This is a cheap way to *really* delete files.  Note that only regular
417 * files are deleted, directories (and therefore names) will remain.
418 * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
419 * System V file system).  In a logging or COW file system, you'll have to
420 * have kernel support.
421 */
422static int
423rm_overwrite(const char *file, struct stat *sbp)
424{
425	struct stat sb, sb2;
426	struct statfs fsb;
427	off_t len;
428	int bsize, fd, wlen;
429	char *buf = NULL;
430
431	fd = -1;
432	if (sbp == NULL) {
433		if (lstat(file, &sb))
434			goto err;
435		sbp = &sb;
436	}
437	if (!S_ISREG(sbp->st_mode))
438		return (1);
439	if (sbp->st_nlink > 1 && !fflag) {
440		warnx("%s (inode %ju): not overwritten due to multiple links",
441		    file, (uintmax_t)sbp->st_ino);
442		return (0);
443	}
444	if ((fd = open(file, O_WRONLY|O_NONBLOCK|O_NOFOLLOW, 0)) == -1)
445		goto err;
446	if (fstat(fd, &sb2))
447		goto err;
448	if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino ||
449	    !S_ISREG(sb2.st_mode)) {
450		errno = EPERM;
451		goto err;
452	}
453	if (fstatfs(fd, &fsb) == -1)
454		goto err;
455	bsize = MAX(fsb.f_iosize, 1024);
456	if ((buf = malloc(bsize)) == NULL)
457		err(1, "%s: malloc", file);
458
459#define	PASS(byte) {							\
460	memset(buf, byte, bsize);					\
461	for (len = sbp->st_size; len > 0; len -= wlen) {		\
462		wlen = len < bsize ? len : bsize;			\
463		if (write(fd, buf, wlen) != wlen)			\
464			goto err;					\
465	}								\
466}
467	PASS(0xff);
468	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
469		goto err;
470	PASS(0x00);
471	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
472		goto err;
473	PASS(0xff);
474	if (!fsync(fd) && !close(fd)) {
475		free(buf);
476		return (1);
477	}
478
479err:	eval = 1;
480	if (buf)
481		free(buf);
482	if (fd != -1)
483		close(fd);
484	warn("%s", file);
485	return (0);
486}
487
488
489static int
490check(const char *path, const char *name, struct stat *sp)
491{
492	int ch, first;
493	char modep[15], *flagsp;
494
495	/* Check -i first. */
496	if (iflag)
497		(void)fprintf(stderr, "remove %s? ", path);
498	else {
499		/*
500		 * If it's not a symbolic link and it's unwritable and we're
501		 * talking to a terminal, ask.  Symbolic links are excluded
502		 * because their permissions are meaningless.  Check stdin_ok
503		 * first because we may not have stat'ed the file.
504		 */
505		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
506		    (!access(name, W_OK) &&
507		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
508		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
509			return (1);
510		strmode(sp->st_mode, modep);
511		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
512			err(1, "fflagstostr");
513		if (Pflag)
514			errx(1,
515			    "%s: -P was specified, but file is not writable",
516			    path);
517		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
518		    modep + 1, modep[10] == ' ' ? "" : " ",
519		    user_from_uid(sp->st_uid, 0),
520		    group_from_gid(sp->st_gid, 0),
521		    *flagsp ? flagsp : "", *flagsp ? " " : "",
522		    path);
523		free(flagsp);
524	}
525	(void)fflush(stderr);
526
527	first = ch = getchar();
528	while (ch != '\n' && ch != EOF)
529		ch = getchar();
530	return (first == 'y' || first == 'Y');
531}
532
533#define ISSLASH(a)	((a)[0] == '/' && (a)[1] == '\0')
534static void
535checkslash(char **argv)
536{
537	char **t, **u;
538	int complained;
539
540	complained = 0;
541	for (t = argv; *t;) {
542		if (ISSLASH(*t)) {
543			if (!complained++)
544				warnx("\"/\" may not be removed");
545			eval = 1;
546			for (u = t; u[0] != NULL; ++u)
547				u[0] = u[1];
548		} else {
549			++t;
550		}
551	}
552}
553
554static int
555check2(char **argv)
556{
557	struct stat st;
558	int first;
559	int ch;
560	int fcount = 0;
561	int dcount = 0;
562	int i;
563	const char *dname = NULL;
564
565	for (i = 0; argv[i]; ++i) {
566		if (lstat(argv[i], &st) == 0) {
567			if (S_ISDIR(st.st_mode)) {
568				++dcount;
569				dname = argv[i];    /* only used if 1 dir */
570			} else {
571				++fcount;
572			}
573		}
574	}
575	first = 0;
576	while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
577		if (dcount && rflag) {
578			fprintf(stderr, "recursively remove");
579			if (dcount == 1)
580				fprintf(stderr, " %s", dname);
581			else
582				fprintf(stderr, " %d dirs", dcount);
583			if (fcount == 1)
584				fprintf(stderr, " and 1 file");
585			else if (fcount > 1)
586				fprintf(stderr, " and %d files", fcount);
587		} else if (dcount + fcount > 3) {
588			fprintf(stderr, "remove %d files", dcount + fcount);
589		} else {
590			return(1);
591		}
592		fprintf(stderr, "? ");
593		fflush(stderr);
594
595		first = ch = getchar();
596		while (ch != '\n' && ch != EOF)
597			ch = getchar();
598		if (ch == EOF)
599			break;
600	}
601	return (first == 'y' || first == 'Y');
602}
603
604#define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
605static void
606checkdot(char **argv)
607{
608	char *p, **save, **t;
609	int complained;
610
611	complained = 0;
612	for (t = argv; *t;) {
613		if ((p = strrchr(*t, '/')) != NULL)
614			++p;
615		else
616			p = *t;
617		if (ISDOT(p)) {
618			if (!complained++)
619				warnx("\".\" and \"..\" may not be removed");
620			eval = 1;
621			for (save = t; (t[0] = t[1]) != NULL; ++t)
622				continue;
623			t = save;
624		} else
625			++t;
626	}
627}
628
629static void
630usage(void)
631{
632
633	(void)fprintf(stderr, "%s\n%s\n",
634	    "usage: rm [-f | -i] [-dIPRrvWx] file ...",
635	    "       unlink file");
636	exit(EX_USAGE);
637}
638
639static void
640siginfo(int sig __unused)
641{
642
643	info = 1;
644}
645