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rm.c revision 1.39
      1 /* $NetBSD: rm.c,v 1.39 2004/01/04 16:04:18 jschauma Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 1990, 1993, 1994, 2003
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 __COPYRIGHT("@(#) Copyright (c) 1990, 1993, 1994\n\
     35 	The Regents of the University of California.  All rights reserved.\n");
     36 #endif /* not lint */
     37 
     38 #ifndef lint
     39 #if 0
     40 static char sccsid[] = "@(#)rm.c	8.8 (Berkeley) 4/27/95";
     41 #else
     42 __RCSID("$NetBSD: rm.c,v 1.39 2004/01/04 16:04:18 jschauma Exp $");
     43 #endif
     44 #endif /* not lint */
     45 
     46 #include <sys/param.h>
     47 #include <sys/stat.h>
     48 #include <sys/types.h>
     49 
     50 #include <err.h>
     51 #include <errno.h>
     52 #include <fcntl.h>
     53 #include <fts.h>
     54 #include <grp.h>
     55 #include <locale.h>
     56 #include <pwd.h>
     57 #include <stdio.h>
     58 #include <stdlib.h>
     59 #include <string.h>
     60 #include <unistd.h>
     61 
     62 int dflag, eval, fflag, iflag, Pflag, stdin_ok, vflag, Wflag;
     63 
     64 int	check(char *, char *, struct stat *);
     65 void	checkdot(char **);
     66 void	rm_file(char **);
     67 void	rm_overwrite(char *, struct stat *);
     68 void	rm_tree(char **);
     69 void	usage(void);
     70 int	main(int, char *[]);
     71 
     72 /*
     73  * For the sake of the `-f' flag, check whether an error number indicates the
     74  * failure of an operation due to an non-existent file, either per se (ENOENT)
     75  * or because its filename argument was illegal (ENAMETOOLONG, ENOTDIR).
     76  */
     77 #define NONEXISTENT(x) \
     78     ((x) == ENOENT || (x) == ENAMETOOLONG || (x) == ENOTDIR)
     79 
     80 /*
     81  * rm --
     82  *	This rm is different from historic rm's, but is expected to match
     83  *	POSIX 1003.2 behavior.  The most visible difference is that -f
     84  *	has two specific effects now, ignore non-existent files and force
     85  * 	file removal.
     86  */
     87 int
     88 main(int argc, char *argv[])
     89 {
     90 	int ch, rflag;
     91 
     92 	setprogname(argv[0]);
     93 	(void)setlocale(LC_ALL, "");
     94 
     95 	Pflag = rflag = 0;
     96 	while ((ch = getopt(argc, argv, "dfiPRrvW")) != -1)
     97 		switch (ch) {
     98 		case 'd':
     99 			dflag = 1;
    100 			break;
    101 		case 'f':
    102 			fflag = 1;
    103 			iflag = 0;
    104 			break;
    105 		case 'i':
    106 			fflag = 0;
    107 			iflag = 1;
    108 			break;
    109 		case 'P':
    110 			Pflag = 1;
    111 			break;
    112 		case 'R':
    113 		case 'r':			/* Compatibility. */
    114 			rflag = 1;
    115 			break;
    116 		case 'v':
    117 			vflag = 1;
    118 			break;
    119 		case 'W':
    120 			Wflag = 1;
    121 			break;
    122 		case '?':
    123 		default:
    124 			usage();
    125 		}
    126 	argc -= optind;
    127 	argv += optind;
    128 
    129 	if (argc < 1)
    130 		usage();
    131 
    132 	checkdot(argv);
    133 
    134 	if (*argv) {
    135 		stdin_ok = isatty(STDIN_FILENO);
    136 
    137 		if (rflag)
    138 			rm_tree(argv);
    139 		else
    140 			rm_file(argv);
    141 	}
    142 
    143 	exit(eval);
    144 	/* NOTREACHED */
    145 }
    146 
    147 void
    148 rm_tree(char **argv)
    149 {
    150 	FTS *fts;
    151 	FTSENT *p;
    152 	int flags, needstat, rval;
    153 
    154 	/*
    155 	 * Remove a file hierarchy.  If forcing removal (-f), or interactive
    156 	 * (-i) or can't ask anyway (stdin_ok), don't stat the file.
    157 	 */
    158 	needstat = !fflag && !iflag && stdin_ok;
    159 
    160 	/*
    161 	 * If the -i option is specified, the user can skip on the pre-order
    162 	 * visit.  The fts_number field flags skipped directories.
    163 	 */
    164 #define	SKIPPED	1
    165 
    166 	flags = FTS_PHYSICAL;
    167 	if (!needstat)
    168 		flags |= FTS_NOSTAT;
    169 	if (Wflag)
    170 		flags |= FTS_WHITEOUT;
    171 	if (!(fts = fts_open(argv, flags,
    172 	    (int (*)(const FTSENT **, const FTSENT **))NULL)))
    173 		err(1, NULL);
    174 	while ((p = fts_read(fts)) != NULL) {
    175 
    176 		switch (p->fts_info) {
    177 		case FTS_DNR:
    178 			if (!fflag || p->fts_errno != ENOENT) {
    179 				warnx("%s: %s", p->fts_path,
    180 						strerror(p->fts_errno));
    181 				eval = 1;
    182 			}
    183 			continue;
    184 		case FTS_ERR:
    185 			errx(EXIT_FAILURE, "%s: %s", p->fts_path,
    186 					strerror(p->fts_errno));
    187 			/* NOTREACHED */
    188 		case FTS_NS:
    189 			/*
    190 			 * FTS_NS: assume that if can't stat the file, it
    191 			 * can't be unlinked.
    192 			 */
    193 			if (fflag && NONEXISTENT(p->fts_errno))
    194 				continue;
    195 			if (needstat) {
    196 				warnx("%s: %s", p->fts_path,
    197 						strerror(p->fts_errno));
    198 				eval = 1;
    199 				continue;
    200 			}
    201 			break;
    202 		case FTS_D:
    203 			/* Pre-order: give user chance to skip. */
    204 			if (!fflag && !check(p->fts_path, p->fts_accpath,
    205 			    p->fts_statp)) {
    206 				(void)fts_set(fts, p, FTS_SKIP);
    207 				p->fts_number = SKIPPED;
    208 			}
    209 			continue;
    210 		case FTS_DP:
    211 			/* Post-order: see if user skipped. */
    212 			if (p->fts_number == SKIPPED)
    213 				continue;
    214 			break;
    215 		default:
    216 			if (!fflag &&
    217 			    !check(p->fts_path, p->fts_accpath, p->fts_statp))
    218 				continue;
    219 		}
    220 
    221 		rval = 0;
    222 		/*
    223 		 * If we can't read or search the directory, may still be
    224 		 * able to remove it.  Don't print out the un{read,search}able
    225 		 * message unless the remove fails.
    226 		 */
    227 		switch (p->fts_info) {
    228 		case FTS_DP:
    229 		case FTS_DNR:
    230 			rval = rmdir(p->fts_accpath);
    231 			if (rval != 0 && fflag && errno == ENOENT)
    232 				continue;
    233 			break;
    234 
    235 		case FTS_W:
    236 			rval = undelete(p->fts_accpath);
    237 			if (rval != 0 && fflag && errno == ENOENT)
    238 				continue;
    239 			break;
    240 
    241 		default:
    242 			if (Pflag)
    243 				rm_overwrite(p->fts_accpath, NULL);
    244 			rval = unlink(p->fts_accpath);
    245 			if (rval != 0 && fflag && NONEXISTENT(errno))
    246 				continue;
    247 			break;
    248 		}
    249 		if (rval != 0) {
    250 			warn("%s", p->fts_path);
    251 			eval = 1;
    252 		} else if (vflag)
    253 			(void)printf("%s\n", p->fts_path);
    254 	}
    255 	if (errno)
    256 		err(1, "fts_read");
    257 }
    258 
    259 void
    260 rm_file(char **argv)
    261 {
    262 	struct stat sb;
    263 	int rval;
    264 	char *f;
    265 
    266 	/*
    267 	 * Remove a file.  POSIX 1003.2 states that, by default, attempting
    268 	 * to remove a directory is an error, so must always stat the file.
    269 	 */
    270 	while ((f = *argv++) != NULL) {
    271 		/* Assume if can't stat the file, can't unlink it. */
    272 		if (lstat(f, &sb)) {
    273 			if (Wflag) {
    274 				sb.st_mode = S_IFWHT|S_IWUSR|S_IRUSR;
    275 			} else {
    276 				if (!fflag || !NONEXISTENT(errno)) {
    277 					warn("%s", f);
    278 					eval = 1;
    279 				}
    280 				continue;
    281 			}
    282 		} else if (Wflag) {
    283 			warnx("%s: %s", f, strerror(EEXIST));
    284 			eval = 1;
    285 			continue;
    286 		}
    287 
    288 		if (S_ISDIR(sb.st_mode) && !dflag) {
    289 			warnx("%s: is a directory", f);
    290 			eval = 1;
    291 			continue;
    292 		}
    293 		if (!fflag && !S_ISWHT(sb.st_mode) && !check(f, f, &sb))
    294 			continue;
    295 		if (S_ISWHT(sb.st_mode))
    296 			rval = undelete(f);
    297 		else if (S_ISDIR(sb.st_mode))
    298 			rval = rmdir(f);
    299 		else {
    300 			if (Pflag)
    301 				rm_overwrite(f, &sb);
    302 			rval = unlink(f);
    303 		}
    304 		if (rval && (!fflag || !NONEXISTENT(errno))) {
    305 			warn("%s", f);
    306 			eval = 1;
    307 		}
    308 		if (vflag && rval == 0)
    309 			(void)printf("%s\n", f);
    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  */
    324 void
    325 rm_overwrite(char *file, struct stat *sbp)
    326 {
    327 	struct stat sb;
    328 	off_t len;
    329 	int fd, wlen;
    330 	char buf[8 * 1024];
    331 
    332 	fd = -1;
    333 	if (sbp == NULL) {
    334 		if (lstat(file, &sb))
    335 			goto err;
    336 		sbp = &sb;
    337 	}
    338 	if (!S_ISREG(sbp->st_mode))
    339 		return;
    340 	if ((fd = open(file, O_WRONLY, 0)) == -1)
    341 		goto err;
    342 
    343 #define	PASS(byte) do {							\
    344 	memset(buf, byte, sizeof(buf));					\
    345 	for (len = sbp->st_size; len > 0; len -= wlen) {		\
    346 		wlen = len < sizeof(buf) ? len : sizeof(buf);		\
    347 		if (write(fd, buf, wlen) != wlen)			\
    348 			goto err;					\
    349 	}								\
    350 } while (/* CONSTCOND */ 0)
    351 	PASS(0xff);
    352 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
    353 		goto err;
    354 	PASS(0x00);
    355 	if (fsync(fd) || lseek(fd, (off_t)0, SEEK_SET))
    356 		goto err;
    357 	PASS(0xff);
    358 	if (!fsync(fd) && !close(fd))
    359 		return;
    360 
    361 err:	eval = 1;
    362 	warn("%s", file);
    363 }
    364 
    365 int
    366 check(char *path, char *name, struct stat *sp)
    367 {
    368 	int ch, first;
    369 	char modep[15];
    370 
    371 	/* Check -i first. */
    372 	if (iflag)
    373 		(void)fprintf(stderr, "remove '%s'? ", path);
    374 	else {
    375 		/*
    376 		 * If it's not a symbolic link and it's unwritable and we're
    377 		 * talking to a terminal, ask.  Symbolic links are excluded
    378 		 * because their permissions are meaningless.  Check stdin_ok
    379 		 * first because we may not have stat'ed the file.
    380 		 */
    381 		if (!stdin_ok || S_ISLNK(sp->st_mode) ||
    382 		    !(access(name, W_OK) && (errno != ETXTBSY)))
    383 			return (1);
    384 		strmode(sp->st_mode, modep);
    385 		(void)fprintf(stderr, "override %s%s%s/%s for '%s'? ",
    386 		    modep + 1, modep[9] == ' ' ? "" : " ",
    387 		    user_from_uid(sp->st_uid, 0),
    388 		    group_from_gid(sp->st_gid, 0), path);
    389 	}
    390 	(void)fflush(stderr);
    391 
    392 	first = ch = getchar();
    393 	while (ch != '\n' && ch != EOF)
    394 		ch = getchar();
    395 	return (first == 'y' || first == 'Y');
    396 }
    397 
    398 /*
    399  * POSIX.2 requires that if "." or ".." are specified as the basename
    400  * portion of an operand, a diagnostic message be written to standard
    401  * error and nothing more be done with such operands.
    402  *
    403  * Since POSIX.2 defines basename as the final portion of a path after
    404  * trailing slashes have been removed, we'll remove them here.
    405  */
    406 #define ISDOT(a) ((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
    407 void
    408 checkdot(char **argv)
    409 {
    410 	char *p, **save, **t;
    411 	int complained;
    412 
    413 	complained = 0;
    414 	for (t = argv; *t;) {
    415 		/* strip trailing slashes */
    416 		p = strrchr(*t, '\0');
    417 		while (--p > *t && *p == '/')
    418 			*p = '\0';
    419 
    420 		/* extract basename */
    421 		if ((p = strrchr(*t, '/')) != NULL)
    422 			++p;
    423 		else
    424 			p = *t;
    425 
    426 		if (ISDOT(p)) {
    427 			if (!complained++)
    428 				warnx("\".\" and \"..\" may not be removed");
    429 			eval = 1;
    430 			for (save = t; (t[0] = t[1]) != NULL; ++t)
    431 				continue;
    432 			t = save;
    433 		} else
    434 			++t;
    435 	}
    436 }
    437 
    438 void
    439 usage(void)
    440 {
    441 
    442 	(void)fprintf(stderr, "usage: %s [-f|-i] [-dPRrvW] file ...\n",
    443 	    getprogname());
    444 	exit(1);
    445 	/* NOTREACHED */
    446 }
    447