rm.c revision 272372 
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/10/bin/rm/rm.c 272372 2014-10-01 16:18:40Z gjb $");
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 <stdint.h>
55#include <stdio.h>
56#include <stdlib.h>
57#include <string.h>
58#include <sysexits.h>
59#include <unistd.h>
60
61static int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
62static int rflag, Iflag, xflag;
63static uid_t uid;
64static volatile sig_atomic_t info;
65
66static int	check(const char *, const char *, struct stat *);
67static int	check2(char **);
68static void	checkdot(char **);
69static void	checkslash(char **);
70static void	rm_file(char **);
71static int	rm_overwrite(const char *, struct stat *);
72static void	rm_tree(char **);
73static void siginfo(int __unused);
74static void	usage(void);
75
76/*
77 * rm --
78 *	This rm is different from historic rm's, but is expected to match
79 *	POSIX 1003.2 behavior.	The most visible difference is that -f
80 *	has two specific effects now, ignore non-existent files and force
81 *	file removal.
82 */
83int
84main(int argc, char *argv[])
85{
86	int ch;
87	char *p;
88
89	/*
90	 * Test for the special case where the utility is called as
91	 * "unlink", for which the functionality provided is greatly
92	 * simplified.
93	 */
94	if ((p = strrchr(argv[0], '/')) == NULL)
95		p = argv[0];
96	else
97		++p;
98	if (strcmp(p, "unlink") == 0) {
99		while (getopt(argc, argv, "") != -1)
100			usage();
101		argc -= optind;
102		argv += optind;
103		if (argc != 1)
104			usage();
105		rm_file(&argv[0]);
106		exit(eval);
107	}
108
109	Pflag = rflag = xflag = 0;
110	while ((ch = getopt(argc, argv, "dfiIPRrvWx")) != -1)
111		switch(ch) {
112		case 'd':
113			dflag = 1;
114			break;
115		case 'f':
116			fflag = 1;
117			iflag = 0;
118			break;
119		case 'i':
120			fflag = 0;
121			iflag = 1;
122			break;
123		case 'I':
124			Iflag = 1;
125			break;
126		case 'P':
127			Pflag = 1;
128			break;
129		case 'R':
130		case 'r':			/* Compatibility. */
131			rflag = 1;
132			break;
133		case 'v':
134			vflag = 1;
135			break;
136		case 'W':
137			Wflag = 1;
138			break;
139		case 'x':
140			xflag = 1;
141			break;
142		default:
143			usage();
144		}
145	argc -= optind;
146	argv += optind;
147
148	if (argc < 1) {
149		if (fflag)
150			return (0);
151		usage();
152	}
153
154	checkdot(argv);
155	if (getenv("POSIXLY_CORRECT") == NULL)
156		checkslash(argv);
157	uid = geteuid();
158
159	(void)signal(SIGINFO, siginfo);
160	if (*argv) {
161		stdin_ok = isatty(STDIN_FILENO);
162
163		if (Iflag) {
164			if (check2(argv) == 0)
165				exit (1);
166		}
167		if (rflag)
168			rm_tree(argv);
169		else
170			rm_file(argv);
171	}
172
173	exit (eval);
174}
175
176static void
177rm_tree(char **argv)
178{
179	FTS *fts;
180	FTSENT *p;
181	int needstat;
182	int flags;
183	int rval;
184
185	/*
186	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
187	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
188	 */
189	needstat = !uid || (!fflag && !iflag && stdin_ok);
190
191	/*
192	 * If the -i option is specified, the user can skip on the pre-order
193	 * visit.  The fts_number field flags skipped directories.
194	 */
195#define	SKIPPED	1
196
197	flags = FTS_PHYSICAL;
198	if (!needstat)
199		flags |= FTS_NOSTAT;
200	if (Wflag)
201		flags |= FTS_WHITEOUT;
202	if (xflag)
203		flags |= FTS_XDEV;
204	if (!(fts = fts_open(argv, flags, NULL))) {
205		if (fflag && errno == ENOENT)
206			return;
207		err(1, "fts_open");
208	}
209	while ((p = fts_read(fts)) != NULL) {
210		switch (p->fts_info) {
211		case FTS_DNR:
212			if (!fflag || p->fts_errno != ENOENT) {
213				warnx("%s: %s",
214				    p->fts_path, strerror(p->fts_errno));
215				eval = 1;
216			}
217			continue;
218		case FTS_ERR:
219			errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
220		case FTS_NS:
221			/*
222			 * Assume that since fts_read() couldn't stat the
223			 * file, it can't be unlinked.
224			 */
225			if (!needstat)
226				break;
227			if (!fflag || p->fts_errno != ENOENT) {
228				warnx("%s: %s",
229				    p->fts_path, strerror(p->fts_errno));
230				eval = 1;
231			}
232			continue;
233		case FTS_D:
234			/* Pre-order: give user chance to skip. */
235			if (!fflag && !check(p->fts_path, p->fts_accpath,
236			    p->fts_statp)) {
237				(void)fts_set(fts, p, FTS_SKIP);
238				p->fts_number = SKIPPED;
239			}
240			else if (!uid &&
241				 (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
242				 !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
243				 lchflags(p->fts_accpath,
244					 p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE)) < 0)
245				goto err;
246			continue;
247		case FTS_DP:
248			/* Post-order: see if user skipped. */
249			if (p->fts_number == SKIPPED)
250				continue;
251			break;
252		default:
253			if (!fflag &&
254			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
255				continue;
256		}
257
258		rval = 0;
259		if (!uid &&
260		    (p->fts_statp->st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
261		    !(p->fts_statp->st_flags & (SF_APPEND|SF_IMMUTABLE)))
262			rval = lchflags(p->fts_accpath,
263				       p->fts_statp->st_flags &= ~(UF_APPEND|UF_IMMUTABLE));
264		if (rval == 0) {
265			/*
266			 * If we can't read or search the directory, may still be
267			 * able to remove it.  Don't print out the un{read,search}able
268			 * message unless the remove fails.
269			 */
270			switch (p->fts_info) {
271			case FTS_DP:
272			case FTS_DNR:
273				rval = rmdir(p->fts_accpath);
274				if (rval == 0 || (fflag && errno == ENOENT)) {
275					if (rval == 0 && vflag)
276						(void)printf("%s\n",
277						    p->fts_path);
278					if (rval == 0 && info) {
279						info = 0;
280						(void)printf("%s\n",
281						    p->fts_path);
282					}
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						(void)printf("%s\n",
292						    p->fts_path);
293					if (info) {
294						info = 0;
295						(void)printf("%s\n",
296						    p->fts_path);
297					}
298					continue;
299				}
300				break;
301
302			case FTS_NS:
303				/*
304				 * Assume that since fts_read() couldn't stat
305				 * the file, it can't be unlinked.
306				 */
307				if (fflag)
308					continue;
309				/* FALLTHROUGH */
310
311			case FTS_F:
312			case FTS_NSOK:
313				if (Pflag)
314					if (!rm_overwrite(p->fts_accpath, p->fts_info ==
315					    FTS_NSOK ? NULL : p->fts_statp))
316						continue;
317				/* FALLTHROUGH */
318
319			default:
320				rval = unlink(p->fts_accpath);
321				if (rval == 0 || (fflag && errno == ENOENT)) {
322					if (rval == 0 && vflag)
323						(void)printf("%s\n",
324						    p->fts_path);
325					if (rval == 0 && info) {
326						info = 0;
327						(void)printf("%s\n",
328						    p->fts_path);
329					}
330					continue;
331				}
332			}
333		}
334err:
335		warn("%s", p->fts_path);
336		eval = 1;
337	}
338	if (!fflag && errno)
339		err(1, "fts_read");
340	fts_close(fts);
341}
342
343static void
344rm_file(char **argv)
345{
346	struct stat sb;
347	int rval;
348	char *f;
349
350	/*
351	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
352	 * to remove a directory is an error, so must always stat the file.
353	 */
354	while ((f = *argv++) != NULL) {
355		/* Assume if can't stat the file, can't unlink it. */
356		if (lstat(f, &sb)) {
357			if (Wflag) {
358				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
359			} else {
360				if (!fflag || errno != ENOENT) {
361					warn("%s", f);
362					eval = 1;
363				}
364				continue;
365			}
366		} else if (Wflag) {
367			warnx("%s: %s", f, strerror(EEXIST));
368			eval = 1;
369			continue;
370		}
371
372		if (S_ISDIR(sb.st_mode) && !dflag) {
373			warnx("%s: is a directory", f);
374			eval = 1;
375			continue;
376		}
377		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
378			continue;
379		rval = 0;
380		if (!uid && !S_ISWHT(sb.st_mode) &&
381		    (sb.st_flags & (UF_APPEND|UF_IMMUTABLE)) &&
382		    !(sb.st_flags & (SF_APPEND|SF_IMMUTABLE)))
383			rval = lchflags(f, sb.st_flags & ~(UF_APPEND|UF_IMMUTABLE));
384		if (rval == 0) {
385			if (S_ISWHT(sb.st_mode))
386				rval = undelete(f);
387			else if (S_ISDIR(sb.st_mode))
388				rval = rmdir(f);
389			else {
390				if (Pflag)
391					if (!rm_overwrite(f, &sb))
392						continue;
393				rval = unlink(f);
394			}
395		}
396		if (rval && (!fflag || errno != ENOENT)) {
397			warn("%s", f);
398			eval = 1;
399		}
400		if (vflag && rval == 0)
401			(void)printf("%s\n", f);
402		if (info && rval == 0) {
403			info = 0;
404			(void)printf("%s\n", f);
405		}
406	}
407}
408
409/*
410 * rm_overwrite --
411 *	Overwrite the file 3 times with varying bit patterns.
412 *
413 * XXX
414 * This is a cheap way to *really* delete files.  Note that only regular
415 * files are deleted, directories (and therefore names) will remain.
416 * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
417 * System V file system).  In a logging or COW file system, you'll have to
418 * have kernel support.
419 */
420static int
421rm_overwrite(const char *file, struct stat *sbp)
422{
423	struct stat sb, sb2;
424	struct statfs fsb;
425	off_t len;
426	int bsize, fd, wlen;
427	char *buf = NULL;
428
429	fd = -1;
430	if (sbp == NULL) {
431		if (lstat(file, &sb))
432			goto err;
433		sbp = &sb;
434	}
435	if (!S_ISREG(sbp->st_mode))
436		return (1);
437	if (sbp->st_nlink > 1 && !fflag) {
438		warnx("%s (inode %ju): not overwritten due to multiple links",
439		    file, (uintmax_t)sbp->st_ino);
440		return (0);
441	}
442	if ((fd = open(file, O_WRONLY|O_NONBLOCK|O_NOFOLLOW, 0)) == -1)
443		goto err;
444	if (fstat(fd, &sb2))
445		goto err;
446	if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino ||
447	    !S_ISREG(sb2.st_mode)) {
448		errno = EPERM;
449		goto err;
450	}
451	if (fstatfs(fd, &fsb) == -1)
452		goto err;
453	bsize = MAX(fsb.f_iosize, 1024);
454	if ((buf = malloc(bsize)) == NULL)
455		err(1, "%s: malloc", file);
456
457#define	PASS(byte) {							\
458	memset(buf, byte, bsize);					\
459	for (len = sbp->st_size; len > 0; len -= wlen) {		\
460		wlen = len < bsize ? len : bsize;			\
461		if (write(fd, buf, wlen) != wlen)			\
462			goto err;					\
463	}								\
464}
465	PASS(0xff);
466	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
467		goto err;
468	PASS(0x00);
469	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
470		goto err;
471	PASS(0xff);
472	if (!fsync(fd) && !close(fd)) {
473		free(buf);
474		return (1);
475	}
476
477err:	eval = 1;
478	if (buf)
479		free(buf);
480	if (fd != -1)
481		close(fd);
482	warn("%s", file);
483	return (0);
484}
485
486
487static int
488check(const char *path, const char *name, struct stat *sp)
489{
490	int ch, first;
491	char modep[15], *flagsp;
492
493	/* Check -i first. */
494	if (iflag)
495		(void)fprintf(stderr, "remove %s? ", path);
496	else {
497		/*
498		 * If it's not a symbolic link and it's unwritable and we're
499		 * talking to a terminal, ask.  Symbolic links are excluded
500		 * because their permissions are meaningless.  Check stdin_ok
501		 * first because we may not have stat'ed the file.
502		 */
503		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
504		    (!access(name, W_OK) &&
505		    !(sp->st_flags & (SF_APPEND|SF_IMMUTABLE)) &&
506		    (!(sp->st_flags & (UF_APPEND|UF_IMMUTABLE)) || !uid)))
507			return (1);
508		strmode(sp->st_mode, modep);
509		if ((flagsp = fflagstostr(sp->st_flags)) == NULL)
510			err(1, "fflagstostr");
511		if (Pflag)
512			errx(1,
513			    "%s: -P was specified, but file is not writable",
514			    path);
515		(void)fprintf(stderr, "override %s%s%s/%s %s%sfor %s? ",
516		    modep + 1, modep[9] == ' ' ? "" : " ",
517		    user_from_uid(sp->st_uid, 0),
518		    group_from_gid(sp->st_gid, 0),
519		    *flagsp ? flagsp : "", *flagsp ? " " : "",
520		    path);
521		free(flagsp);
522	}
523	(void)fflush(stderr);
524
525	first = ch = getchar();
526	while (ch != '\n' && ch != EOF)
527		ch = getchar();
528	return (first == 'y' || first == 'Y');
529}
530
531#define ISSLASH(a)	((a)[0] == '/' && (a)[1] == '\0')
532static void
533checkslash(char **argv)
534{
535	char **t, **u;
536	int complained;
537
538	complained = 0;
539	for (t = argv; *t;) {
540		if (ISSLASH(*t)) {
541			if (!complained++)
542				warnx("\"/\" may not be removed");
543			eval = 1;
544			for (u = t; u[0] != NULL; ++u)
545				u[0] = u[1];
546		} else {
547			++t;
548		}
549	}
550}
551
552static int
553check2(char **argv)
554{
555	struct stat st;
556	int first;
557	int ch;
558	int fcount = 0;
559	int dcount = 0;
560	int i;
561	const char *dname = NULL;
562
563	for (i = 0; argv[i]; ++i) {
564		if (lstat(argv[i], &st) == 0) {
565			if (S_ISDIR(st.st_mode)) {
566				++dcount;
567				dname = argv[i];    /* only used if 1 dir */
568			} else {
569				++fcount;
570			}
571		}
572	}
573	first = 0;
574	while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
575		if (dcount && rflag) {
576			fprintf(stderr, "recursively remove");
577			if (dcount == 1)
578				fprintf(stderr, " %s", dname);
579			else
580				fprintf(stderr, " %d dirs", dcount);
581			if (fcount == 1)
582				fprintf(stderr, " and 1 file");
583			else if (fcount > 1)
584				fprintf(stderr, " and %d files", fcount);
585		} else if (dcount + fcount > 3) {
586			fprintf(stderr, "remove %d files", dcount + fcount);
587		} else {
588			return(1);
589		}
590		fprintf(stderr, "? ");
591		fflush(stderr);
592
593		first = ch = getchar();
594		while (ch != '\n' && ch != EOF)
595			ch = getchar();
596		if (ch == EOF)
597			break;
598	}
599	return (first == 'y' || first == 'Y');
600}
601
602#define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
603static void
604checkdot(char **argv)
605{
606	char *p, **save, **t;
607	int complained;
608
609	complained = 0;
610	for (t = argv; *t;) {
611		if ((p = strrchr(*t, '/')) != NULL)
612			++p;
613		else
614			p = *t;
615		if (ISDOT(p)) {
616			if (!complained++)
617				warnx("\".\" and \"..\" may not be removed");
618			eval = 1;
619			for (save = t; (t[0] = t[1]) != NULL; ++t)
620				continue;
621			t = save;
622		} else
623			++t;
624	}
625}
626
627static void
628usage(void)
629{
630
631	(void)fprintf(stderr, "%s\n%s\n",
632	    "usage: rm [-f | -i] [-dIPRrvWx] file ...",
633	    "       unlink file");
634	exit(EX_USAGE);
635}
636
637static void
638siginfo(int sig __unused)
639{
640
641	info = 1;
642}
643