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compress.c revision 1.27 
      1 /*	$NetBSD: compress.c,v 1.27 2022/05/22 19:41:49 rillig 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\
     35  The Regents of the University of California.  All rights reserved.");
     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 1.27 2022/05/22 19:41:49 rillig 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 static void	compress(const char *, const char *, int);
     59 static void	cwarn(const char *, ...) __printflike(1, 2);
     60 static void	cwarnx(const char *, ...) __printflike(1, 2);
     61 static void	decompress(const char *, const char *, int);
     62 static int	permission(const char *);
     63 static void	setfile(const char *, struct stat *);
     64 __dead static void	usage(int);
     65 
     66 extern FILE *zopen(const char *fname, const char *mode, int bits);
     67 
     68 static int eval, force, verbose;
     69 static int isstdout, isstdin;
     70 
     71 int
     72 main(int argc, char **argv)
     73 {
     74 	enum {COMPRESS, DECOMPRESS} style = COMPRESS;
     75 	size_t len;
     76 	int bits, cat, ch;
     77 	char *p, newname[MAXPATHLEN];
     78 
     79 	if ((p = strrchr(argv[0], '/')) == NULL)
     80 		p = argv[0];
     81 	else
     82 		++p;
     83 	if (!strcmp(p, "uncompress"))
     84 		style = DECOMPRESS;
     85 	else if (!strcmp(p, "compress"))
     86 		style = COMPRESS;
     87 	else if (!strcmp(p, "zcat")) {
     88 		style = DECOMPRESS;
     89 		cat = 1;
     90 	} else
     91 		errx(1, "unknown program name");
     92 
     93 	bits = cat = 0;
     94 	while ((ch = getopt(argc, argv, "b:cdfv")) != -1)
     95 		switch (ch) {
     96 		case 'b':
     97 			bits = strtol(optarg, &p, 10);
     98 			if (*p)
     99 				errx(1, "illegal bit count -- %s", optarg);
    100 			break;
    101 		case 'c':
    102 			cat = 1;
    103 			break;
    104 		case 'd':		/* Backward compatible. */
    105 			style = DECOMPRESS;
    106 			break;
    107 		case 'f':
    108 			force = 1;
    109 			break;
    110 		case 'v':
    111 			verbose = 1;
    112 			break;
    113 		case '?':
    114 		default:
    115 			usage(style == COMPRESS);
    116 		}
    117 	argc -= optind;
    118 	argv += optind;
    119 
    120 	if (argc == 0) {
    121 		switch (style) {
    122 		case COMPRESS:
    123 			isstdout = 1;
    124 			isstdin = 1;
    125 			(void)compress("/dev/stdin", "/dev/stdout", bits);
    126 			break;
    127 		case DECOMPRESS:
    128 			isstdout = 1;
    129 			isstdin = 1;
    130 			(void)decompress("/dev/stdin", "/dev/stdout", bits);
    131 			break;
    132 		}
    133 		exit (eval);
    134 	}
    135 
    136 	if (cat == 1 && argc > 1)
    137 		errx(1, "the -c option permits only a single file argument");
    138 
    139 	for (; *argv; ++argv) {
    140 		isstdout = 0;
    141 		switch (style) {
    142 		case COMPRESS:
    143 			if (cat) {
    144 				isstdout = 1;
    145 				compress(*argv, "/dev/stdout", bits);
    146 				break;
    147 			}
    148 			if ((p = strrchr(*argv, '.')) != NULL &&
    149 			    !strcmp(p, ".Z")) {
    150 				cwarnx("%s: name already has trailing .Z",
    151 				    *argv);
    152 				break;
    153 			}
    154 			len = strlen(*argv);
    155 			if (len > sizeof(newname) - 3) {
    156 				cwarnx("%s: name too long", *argv);
    157 				break;
    158 			}
    159 			memmove(newname, *argv, len);
    160 			newname[len] = '.';
    161 			newname[len + 1] = 'Z';
    162 			newname[len + 2] = '\0';
    163 			compress(*argv, newname, bits);
    164 			break;
    165 		case DECOMPRESS:
    166 			len = strlen(*argv);
    167 			if ((p = strrchr(*argv, '.')) == NULL ||
    168 			    strcmp(p, ".Z")) {
    169 				if (len > sizeof(newname) - 3) {
    170 					cwarnx("%s: name too long", *argv);
    171 					break;
    172 				}
    173 				memmove(newname, *argv, len);
    174 				newname[len] = '.';
    175 				newname[len + 1] = 'Z';
    176 				newname[len + 2] = '\0';
    177 				decompress(newname,
    178 				    cat ? "/dev/stdout" : *argv, bits);
    179 				if (cat)
    180 					isstdout = 1;
    181 			} else {
    182 				if (len - 2 > sizeof(newname) - 1) {
    183 					cwarnx("%s: name too long", *argv);
    184 					break;
    185 				}
    186 				memmove(newname, *argv, len - 2);
    187 				newname[len - 2] = '\0';
    188 				decompress(*argv,
    189 				    cat ? "/dev/stdout" : newname, bits);
    190 				if (cat)
    191 					isstdout = 1;
    192 			}
    193 			break;
    194 		}
    195 	}
    196 	exit (eval);
    197 }
    198 
    199 static void
    200 compress(const char *in, const char *out, int bits)
    201 {
    202 	size_t nr;
    203 	struct stat isb, sb;
    204 	const char *error = NULL;
    205 	FILE *ifp, *ofp;
    206 	int exists, isreg, oreg;
    207 	u_char buf[BUFSIZ];
    208 
    209 	if (!isstdout) {
    210 		exists = !stat(out, &sb);
    211 		if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
    212 			return;
    213 		oreg = !exists || S_ISREG(sb.st_mode);
    214 	} else
    215 		oreg = 0;
    216 
    217 	ifp = ofp = NULL;
    218 	if ((ifp = fopen(in, "r")) == NULL) {
    219 		cwarn("%s", in);
    220 		return;
    221 	}
    222 
    223 	if (!isstdin) {
    224 		if (stat(in, &isb)) {		/* DON'T FSTAT! */
    225 			cwarn("%s", in);
    226 			goto err;
    227 		}
    228 		if (!S_ISREG(isb.st_mode))
    229 			isreg = 0;
    230 		else
    231 			isreg = 1;
    232 	} else
    233 		isreg = 0;
    234 
    235 	if ((ofp = zopen(out, "w", bits)) == NULL) {
    236 		cwarn("%s", out);
    237 		goto err;
    238 	}
    239 	oreg <<= 1;
    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))
    247 		error = in;
    248 	if (fclose(ifp))
    249 		if (error == NULL)
    250 			error = in;
    251 	if (fclose(ofp))
    252 		if (error == NULL)
    253 			error = out;
    254 	ifp = NULL;
    255 	ofp = NULL;
    256 	if (error) {
    257 		cwarn("%s", error);
    258 		goto err;
    259 	}
    260 
    261 	if (isreg && oreg) {
    262 		if (stat(out, &sb)) {
    263 			cwarn("%s", out);
    264 			goto err;
    265 		}
    266 
    267 		if (!force && sb.st_size >= isb.st_size) {
    268 			if (verbose)
    269 		(void)printf("%s: file would grow; left unmodified\n", in);
    270 			goto err;
    271 		}
    272 
    273 		setfile(out, &isb);
    274 
    275 		if (unlink(in))
    276 			cwarn("%s", in);
    277 
    278 		if (verbose) {
    279 			(void)printf("%s: ", out);
    280 			if (isb.st_size > sb.st_size)
    281 				(void)printf("%.0f%% compression\n",
    282 				    ((double)sb.st_size / isb.st_size) * 100.0);
    283 			else
    284 				(void)printf("%.0f%% expansion\n",
    285 				    ((double)isb.st_size / sb.st_size) * 100.0);
    286 		}
    287 	}
    288 	return;
    289 
    290 err:	if (ofp)
    291 		(void)fclose(ofp);
    292 	if (oreg == 2)
    293 		(void)unlink(out);
    294 	if (ifp)
    295 		(void)fclose(ifp);
    296 }
    297 
    298 static void
    299 decompress(const char *in, const char *out, int bits)
    300 {
    301 	size_t 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 	oreg <<= 1;
    338 	while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
    339 		if (fwrite(buf, 1, nr, ofp) != nr) {
    340 			cwarn("%s", out);
    341 			goto err;
    342 		}
    343 
    344 	if (ferror(ifp)) {
    345 		cwarn("%s", in);
    346 		goto err;
    347 	}
    348 	if (fclose(ifp)) {
    349 		ifp = NULL;
    350 		cwarn("%s", in);
    351 		goto err;
    352 	}
    353 	ifp = NULL;
    354 
    355 	if (fclose(ofp)) {
    356 		ofp = NULL;
    357 		cwarn("%s", out);
    358 		goto err;
    359 	}
    360 
    361 	if (isreg && oreg) {
    362 		setfile(out, &sb);
    363 
    364 		if (unlink(in))
    365 			cwarn("%s", in);
    366 	}
    367 	return;
    368 
    369 err:	if (ofp)
    370 		(void)fclose(ofp);
    371 	if (oreg == 2)
    372 		(void)unlink(out);
    373 	if (ifp)
    374 		(void)fclose(ifp);
    375 }
    376 
    377 static void
    378 setfile(const char *name, struct stat *fs)
    379 {
    380 	static struct timeval tv[2];
    381 
    382 	fs->st_mode &= S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO;
    383 
    384 	TIMESPEC_TO_TIMEVAL(&tv[0], &fs->st_atimespec);
    385 	TIMESPEC_TO_TIMEVAL(&tv[1], &fs->st_mtimespec);
    386 	if (utimes(name, tv))
    387 		cwarn("utimes: %s", name);
    388 
    389 	/*
    390 	 * Changing the ownership probably won't succeed, unless we're root
    391 	 * or POSIX_CHOWN_RESTRICTED is not set.  Set uid/gid before setting
    392 	 * the mode; current BSD behavior is to remove all setuid bits on
    393 	 * chown.  If chown fails, lose setuid/setgid bits.
    394 	 */
    395 	if (chown(name, fs->st_uid, fs->st_gid)) {
    396 		if (errno != EPERM)
    397 			cwarn("chown: %s", name);
    398 		fs->st_mode &= ~(S_ISUID|S_ISGID);
    399 	}
    400 	if (chmod(name, fs->st_mode))
    401 		cwarn("chown: %s", name);
    402 
    403 	/*
    404 	 * Restore the file's flags.  However, do this only if the original
    405 	 * file had any flags set; this avoids a warning on file-systems that
    406 	 * do not support flags.
    407 	 */
    408 	if (fs->st_flags != 0 && chflags(name, fs->st_flags))
    409 		cwarn("chflags: %s", name);
    410 }
    411 
    412 static int
    413 permission(const char *fname)
    414 {
    415 	int ch, first;
    416 
    417 	if (!isatty(fileno(stderr)))
    418 		return (0);
    419 	(void)fprintf(stderr, "overwrite %s? ", fname);
    420 	first = ch = getchar();
    421 	while (ch != '\n' && ch != EOF)
    422 		ch = getchar();
    423 	return (first == 'y');
    424 }
    425 
    426 static void
    427 usage(int iscompress)
    428 {
    429 	if (iscompress)
    430 		(void)fprintf(stderr,
    431 		    "usage: compress [-cdfv] [-b bits] [file ...]\n");
    432 	else
    433 		(void)fprintf(stderr,
    434 		    "usage: uncompress [-cdfv] [-b bits] [file ...]\n");
    435 	exit(1);
    436 }
    437 
    438 static void
    439 cwarnx(const char *fmt, ...)
    440 {
    441 	va_list ap;
    442 
    443 	va_start(ap, fmt);
    444 	vwarnx(fmt, ap);
    445 	va_end(ap);
    446 	eval = 1;
    447 }
    448 
    449 static void
    450 cwarn(const char *fmt, ...)
    451 {
    452 	va_list ap;
    453 
    454 	va_start(ap, fmt);
    455 	vwarn(fmt, ap);
    456 	va_end(ap);
    457 	eval = 1;
    458 }
    459