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compress.c revision 1.20 
      1 /*	$NetBSD: compress.c,v 1.20 2003/08/07 11:13:28 agc Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1992, 1993
      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) 1992, 1993\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[] = "@(#)compress.c	8.2 (Berkeley) 1/7/94";
     41 #else
     42 __RCSID("$NetBSD: compress.c,v 1.20 2003/08/07 11:13:28 agc Exp $");
     43 #endif
     44 #endif /* not lint */
     45 
     46 #include <sys/param.h>
     47 #include <sys/time.h>
     48 #include <sys/stat.h>
     49 
     50 #include <err.h>
     51 #include <errno.h>
     52 #include <stdarg.h>
     53 #include <stdio.h>
     54 #include <stdlib.h>
     55 #include <string.h>
     56 #include <unistd.h>
     57 
     58 void	compress(char *, char *, int);
     59 void	cwarn(const char *, ...) __attribute__((__format__(__printf__,1,2)));
     60 void	cwarnx(const char *, ...) __attribute__((__format__(__printf__,1,2)));
     61 void	decompress(char *, char *, int);
     62 int	permission(char *);
     63 void	setfile(char *, struct stat *);
     64 void	usage(int);
     65 
     66 int	main(int, char *[]);
     67 extern FILE *zopen(const char *fname, const char *mode, int bits);
     68 
     69 int eval, force, verbose;
     70 int isstdout, isstdin;
     71 
     72 int
     73 main(int argc, char **argv)
     74 {
     75         enum {COMPRESS, DECOMPRESS} style = COMPRESS;
     76 	size_t len;
     77 	int bits, cat, ch;
     78 	char *p, newname[MAXPATHLEN];
     79 
     80 	if ((p = strrchr(argv[0], '/')) == NULL)
     81 		p = argv[0];
     82 	else
     83 		++p;
     84 	if (!strcmp(p, "uncompress"))
     85 		style = DECOMPRESS;
     86         else if (!strcmp(p, "compress"))
     87                 style = COMPRESS;
     88         else if (!strcmp(p, "zcat")) {
     89                 style = DECOMPRESS;
     90                 cat = 1;
     91         }
     92 	else
     93 		errx(1, "unknown program name");
     94 
     95 	bits = cat = 0;
     96 	while ((ch = getopt(argc, argv, "b:cdfv")) != -1)
     97 		switch(ch) {
     98 		case 'b':
     99 			bits = strtol(optarg, &p, 10);
    100 			if (*p)
    101 				errx(1, "illegal bit count -- %s", optarg);
    102 			break;
    103 		case 'c':
    104 			cat = 1;
    105 			break;
    106 		case 'd':		/* Backward compatible. */
    107 			style = DECOMPRESS;
    108 			break;
    109 		case 'f':
    110 			force = 1;
    111 			break;
    112 		case 'v':
    113 			verbose = 1;
    114 			break;
    115 		case '?':
    116 		default:
    117 			usage(style == COMPRESS);
    118 		}
    119 	argc -= optind;
    120 	argv += optind;
    121 
    122 	if (argc == 0) {
    123 		switch(style) {
    124 		case COMPRESS:
    125 			isstdout = 1;
    126 			isstdin = 1;
    127 			(void)compress("/dev/stdin", "/dev/stdout", bits);
    128 			break;
    129 		case DECOMPRESS:
    130 			isstdout = 1;
    131 			isstdin = 1;
    132 			(void)decompress("/dev/stdin", "/dev/stdout", bits);
    133 			break;
    134 		}
    135 		exit (eval);
    136 	}
    137 
    138 	if (cat == 1 && argc > 1)
    139 		errx(1, "the -c option permits only a single file argument");
    140 
    141 	for (; *argv; ++argv) {
    142 		isstdout = 0;
    143 		switch(style) {
    144 		case COMPRESS:
    145 			if (cat) {
    146 				isstdout = 1;
    147 				compress(*argv, "/dev/stdout", bits);
    148 				break;
    149 			}
    150 			if ((p = strrchr(*argv, '.')) != NULL &&
    151 			    !strcmp(p, ".Z")) {
    152 				cwarnx("%s: name already has trailing .Z",
    153 				    *argv);
    154 				break;
    155 			}
    156 			len = strlen(*argv);
    157 			if (len > sizeof(newname) - 3) {
    158 				cwarnx("%s: name too long", *argv);
    159 				break;
    160 			}
    161 			memmove(newname, *argv, len);
    162 			newname[len] = '.';
    163 			newname[len + 1] = 'Z';
    164 			newname[len + 2] = '\0';
    165 			compress(*argv, newname, bits);
    166 			break;
    167 		case DECOMPRESS:
    168 			len = strlen(*argv);
    169 			if ((p = strrchr(*argv, '.')) == NULL ||
    170 			    strcmp(p, ".Z")) {
    171 				if (len > sizeof(newname) - 3) {
    172 					cwarnx("%s: name too long", *argv);
    173 					break;
    174 				}
    175 				memmove(newname, *argv, len);
    176 				newname[len] = '.';
    177 				newname[len + 1] = 'Z';
    178 				newname[len + 2] = '\0';
    179 				decompress(newname,
    180 				    cat ? "/dev/stdout" : *argv, bits);
    181 				if (cat)
    182 					isstdout = 1;
    183 			} else {
    184 				if (len - 2 > sizeof(newname) - 1) {
    185 					cwarnx("%s: name too long", *argv);
    186 					break;
    187 				}
    188 				memmove(newname, *argv, len - 2);
    189 				newname[len - 2] = '\0';
    190 				decompress(*argv,
    191 				    cat ? "/dev/stdout" : newname, bits);
    192 				if (cat)
    193 					isstdout = 1;
    194 			}
    195 			break;
    196 		}
    197 	}
    198 	exit (eval);
    199 }
    200 
    201 void
    202 compress(char *in, char *out, int bits)
    203 {
    204 	int nr;
    205 	struct stat isb, sb;
    206 	FILE *ifp, *ofp;
    207 	int exists, isreg, oreg;
    208 	u_char buf[BUFSIZ];
    209 
    210 	if (!isstdout) {
    211 		exists = !stat(out, &sb);
    212 		if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
    213 			return;
    214 		oreg = !exists || S_ISREG(sb.st_mode);
    215 	} else
    216 		oreg = 0;
    217 
    218 	ifp = ofp = NULL;
    219 	if ((ifp = fopen(in, "r")) == NULL) {
    220 		cwarn("%s", in);
    221 		return;
    222 	}
    223 
    224 	if (!isstdin) {
    225 		if (stat(in, &isb)) {		/* DON'T FSTAT! */
    226 			cwarn("%s", in);
    227 			goto err;
    228 		}
    229 		if (!S_ISREG(isb.st_mode))
    230 			isreg = 0;
    231 		else
    232 			isreg = 1;
    233 	} else
    234 		isreg = 0;
    235 
    236 	if ((ofp = zopen(out, "w", bits)) == NULL) {
    237 		cwarn("%s", out);
    238 		goto err;
    239 	}
    240 	while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
    241 		if (fwrite(buf, 1, nr, ofp) != nr) {
    242 			cwarn("%s", out);
    243 			goto err;
    244 		}
    245 
    246 	if (ferror(ifp) || fclose(ifp)) {
    247 		cwarn("%s", in);
    248 		goto err;
    249 	}
    250 	ifp = NULL;
    251 
    252 	if (fclose(ofp)) {
    253 		cwarn("%s", out);
    254 		goto err;
    255 	}
    256 	ofp = NULL;
    257 
    258 	if (isreg && oreg) {
    259 		if (stat(out, &sb)) {
    260 			cwarn("%s", out);
    261 			goto err;
    262 		}
    263 
    264 		if (!force && sb.st_size >= isb.st_size) {
    265 			if (verbose)
    266 		(void)printf("%s: file would grow; left unmodified\n", in);
    267 			if (unlink(out))
    268 				cwarn("%s", out);
    269 			goto err;
    270 		}
    271 
    272 		setfile(out, &isb);
    273 
    274 		if (unlink(in))
    275 			cwarn("%s", in);
    276 
    277 		if (verbose) {
    278 			(void)printf("%s: ", out);
    279 			if (isb.st_size > sb.st_size)
    280 				(void)printf("%.0f%% compression\n",
    281 				    ((double)sb.st_size / isb.st_size) * 100.0);
    282 			else
    283 				(void)printf("%.0f%% expansion\n",
    284 				    ((double)isb.st_size / sb.st_size) * 100.0);
    285 		}
    286 	}
    287 	return;
    288 
    289 err:	if (ofp) {
    290 		if (oreg)
    291 			(void)unlink(out);
    292 		(void)fclose(ofp);
    293 	}
    294 	if (ifp)
    295 		(void)fclose(ifp);
    296 }
    297 
    298 void
    299 decompress(char *in, char *out, int bits)
    300 {
    301 	int nr;
    302 	struct stat sb;
    303 	FILE *ifp, *ofp;
    304 	int exists, isreg, oreg;
    305 	u_char buf[BUFSIZ];
    306 
    307 	if (!isstdout) {
    308 		exists = !stat(out, &sb);
    309 		if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
    310 			return;
    311 		oreg = !exists || S_ISREG(sb.st_mode);
    312 	} else
    313 		oreg = 0;
    314 
    315 	ifp = ofp = NULL;
    316 	if ((ofp = fopen(out, "w")) == NULL) {
    317 		cwarn("%s", out);
    318 		return;
    319 	}
    320 
    321 	if ((ifp = zopen(in, "r", bits)) == NULL) {
    322 		cwarn("%s", in);
    323 		goto err;
    324 	}
    325 	if (!isstdin) {
    326 		if (stat(in, &sb)) {
    327 			cwarn("%s", in);
    328 			goto err;
    329 		}
    330 		if (!S_ISREG(sb.st_mode))
    331 			isreg = 0;
    332 		else
    333 			isreg = 1;
    334 	} else
    335 		isreg = 0;
    336 
    337 	while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
    338 		if (fwrite(buf, 1, nr, ofp) != nr) {
    339 			cwarn("%s", out);
    340 			goto err;
    341 		}
    342 
    343 	if (ferror(ifp) || fclose(ifp)) {
    344 		cwarn("%s", in);
    345 		goto err;
    346 	}
    347 	ifp = NULL;
    348 
    349 	if (fclose(ofp)) {
    350 		cwarn("%s", out);
    351 		goto err;
    352 	}
    353 
    354 	if (isreg && oreg) {
    355 		setfile(out, &sb);
    356 
    357 		if (unlink(in))
    358 			cwarn("%s", in);
    359 	}
    360 	return;
    361 
    362 err:	if (ofp) {
    363 		if (oreg)
    364 			(void)unlink(out);
    365 		(void)fclose(ofp);
    366 	}
    367 	if (ifp)
    368 		(void)fclose(ifp);
    369 }
    370 
    371 void
    372 setfile(char *name, struct stat *fs)
    373 {
    374 	static struct timeval tv[2];
    375 
    376 	fs->st_mode &= S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO;
    377 
    378 	TIMESPEC_TO_TIMEVAL(&tv[0], &fs->st_atimespec);
    379 	TIMESPEC_TO_TIMEVAL(&tv[1], &fs->st_mtimespec);
    380 	if (utimes(name, tv))
    381 		cwarn("utimes: %s", name);
    382 
    383 	/*
    384 	 * Changing the ownership probably won't succeed, unless we're root
    385 	 * or POSIX_CHOWN_RESTRICTED is not set.  Set uid/gid before setting
    386 	 * the mode; current BSD behavior is to remove all setuid bits on
    387 	 * chown.  If chown fails, lose setuid/setgid bits.
    388 	 */
    389 	if (chown(name, fs->st_uid, fs->st_gid)) {
    390 		if (errno != EPERM)
    391 			cwarn("chown: %s", name);
    392 		fs->st_mode &= ~(S_ISUID|S_ISGID);
    393 	}
    394 	if (chmod(name, fs->st_mode))
    395 		cwarn("chown: %s", name);
    396 
    397 	/*
    398 	 * Restore the file's flags.  However, do this only if the original
    399 	 * file had any flags set; this avoids a warning on file-systems that
    400 	 * do not support flags.
    401 	 */
    402 	if (fs->st_flags != 0 && chflags(name, fs->st_flags))
    403 		cwarn("chflags: %s", name);
    404 }
    405 
    406 int
    407 permission(char *fname)
    408 {
    409 	int ch, first;
    410 
    411 	if (!isatty(fileno(stderr)))
    412 		return (0);
    413 	(void)fprintf(stderr, "overwrite %s? ", fname);
    414 	first = ch = getchar();
    415 	while (ch != '\n' && ch != EOF)
    416 		ch = getchar();
    417 	return (first == 'y');
    418 }
    419 
    420 void
    421 usage(int iscompress)
    422 {
    423 	if (iscompress)
    424 		(void)fprintf(stderr,
    425 		    "usage: compress [-cfv] [-b bits] [file ...]\n");
    426 	else
    427 		(void)fprintf(stderr,
    428 		    "usage: uncompress [-c] [-b bits] [file ...]\n");
    429 	exit(1);
    430 }
    431 
    432 void
    433 cwarnx(const char *fmt, ...)
    434 {
    435 	va_list ap;
    436 
    437 	va_start(ap, fmt);
    438 	vwarnx(fmt, ap);
    439 	va_end(ap);
    440 	eval = 1;
    441 }
    442 
    443 void
    444 cwarn(const char *fmt, ...)
    445 {
    446 	va_list ap;
    447 
    448 	va_start(ap, fmt);
    449 	vwarn(fmt, ap);
    450 	va_end(ap);
    451 	eval = 1;
    452 }
    453