xref: /freebsd/usr.bin/compress/compress.c (revision 7aa383846770374466b1dcb2cefd71bde9acf463)
1 /*-
2  * Copyright (c) 1992, 1993
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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 static const char copyright[] =
36 "@(#) Copyright (c) 1992, 1993\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif
39 
40 #if 0
41 #ifndef lint
42 static char sccsid[] = "@(#)compress.c	8.2 (Berkeley) 1/7/94";
43 #endif
44 #endif
45 
46 #include <sys/cdefs.h>
47 __FBSDID("$FreeBSD$");
48 
49 #include <sys/param.h>
50 #include <sys/stat.h>
51 #include <sys/time.h>
52 
53 #include <err.h>
54 #include <errno.h>
55 #include <stdarg.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60 
61 #include "zopen.h"
62 
63 void	compress(const char *, const char *, int);
64 void	cwarn(const char *, ...) __printflike(1, 2);
65 void	cwarnx(const char *, ...) __printflike(1, 2);
66 void	decompress(const char *, const char *, int);
67 int	permission(const char *);
68 void	setfile(const char *, struct stat *);
69 void	usage(int);
70 
71 int eval, force, verbose;
72 
73 int
74 main(int argc, char *argv[])
75 {
76 	enum {COMPRESS, DECOMPRESS} style;
77 	size_t len;
78 	int bits, cat, ch;
79 	char *p, newname[MAXPATHLEN];
80 
81 	cat = 0;
82 	if ((p = rindex(argv[0], '/')) == NULL)
83 		p = argv[0];
84 	else
85 		++p;
86 	if (!strcmp(p, "uncompress"))
87 		style = DECOMPRESS;
88 	else if (!strcmp(p, "compress"))
89 		style = COMPRESS;
90 	else if (!strcmp(p, "zcat")) {
91 		cat = 1;
92 		style = DECOMPRESS;
93 	} else
94 		errx(1, "unknown program name");
95 
96 	bits = 0;
97 	while ((ch = getopt(argc, argv, "b:cdfv")) != -1)
98 		switch(ch) {
99 		case 'b':
100 			bits = strtol(optarg, &p, 10);
101 			if (*p)
102 				errx(1, "illegal bit count -- %s", optarg);
103 			break;
104 		case 'c':
105 			cat = 1;
106 			break;
107 		case 'd':		/* Backward compatible. */
108 			style = DECOMPRESS;
109 			break;
110 		case 'f':
111 			force = 1;
112 			break;
113 		case 'v':
114 			verbose = 1;
115 			break;
116 		case '?':
117 		default:
118 			usage(style == COMPRESS);
119 		}
120 	argc -= optind;
121 	argv += optind;
122 
123 	if (argc == 0) {
124 		switch(style) {
125 		case COMPRESS:
126 			(void)compress("/dev/stdin", "/dev/stdout", bits);
127 			break;
128 		case DECOMPRESS:
129 			(void)decompress("/dev/stdin", "/dev/stdout", bits);
130 			break;
131 		}
132 		exit (eval);
133 	}
134 
135 	if (cat == 1 && argc > 1)
136 		errx(1, "the -c option permits only a single file argument");
137 
138 	for (; *argv; ++argv)
139 		switch(style) {
140 		case COMPRESS:
141 			if (strcmp(*argv, "-") == 0) {
142 				compress("/dev/stdin", "/dev/stdout", bits);
143 				break;
144 			} else if (cat) {
145 				compress(*argv, "/dev/stdout", bits);
146 				break;
147 			}
148 			if ((p = rindex(*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 			if (strcmp(*argv, "-") == 0) {
167 				decompress("/dev/stdin", "/dev/stdout", bits);
168 				break;
169 			}
170 			len = strlen(*argv);
171 			if ((p = rindex(*argv, '.')) == NULL ||
172 			    strcmp(p, ".Z")) {
173 				if (len > sizeof(newname) - 3) {
174 					cwarnx("%s: name too long", *argv);
175 					break;
176 				}
177 				memmove(newname, *argv, len);
178 				newname[len] = '.';
179 				newname[len + 1] = 'Z';
180 				newname[len + 2] = '\0';
181 				decompress(newname,
182 				    cat ? "/dev/stdout" : *argv, bits);
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 			}
193 			break;
194 		}
195 	exit (eval);
196 }
197 
198 void
199 compress(const char *in, const char *out, int bits)
200 {
201 	size_t nr;
202 	struct stat isb, sb;
203 	FILE *ifp, *ofp;
204 	int exists, isreg, oreg;
205 	u_char buf[1024];
206 
207 	exists = !stat(out, &sb);
208 	if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
209 		return;
210 	isreg = oreg = !exists || S_ISREG(sb.st_mode);
211 
212 	ifp = ofp = NULL;
213 	if ((ifp = fopen(in, "r")) == NULL) {
214 		cwarn("%s", in);
215 		return;
216 	}
217 	if (stat(in, &isb)) {		/* DON'T FSTAT! */
218 		cwarn("%s", in);
219 		goto err;
220 	}
221 	if (!S_ISREG(isb.st_mode))
222 		isreg = 0;
223 
224 	if ((ofp = zopen(out, "w", bits)) == NULL) {
225 		cwarn("%s", out);
226 		goto err;
227 	}
228 	while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
229 		if (fwrite(buf, 1, nr, ofp) != nr) {
230 			cwarn("%s", out);
231 			goto err;
232 		}
233 
234 	if (ferror(ifp) || fclose(ifp)) {
235 		cwarn("%s", in);
236 		goto err;
237 	}
238 	ifp = NULL;
239 
240 	if (fclose(ofp)) {
241 		cwarn("%s", out);
242 		goto err;
243 	}
244 	ofp = NULL;
245 
246 	if (isreg) {
247 		if (stat(out, &sb)) {
248 			cwarn("%s", out);
249 			goto err;
250 		}
251 
252 		if (!force && sb.st_size >= isb.st_size) {
253 			if (verbose)
254 		(void)fprintf(stderr, "%s: file would grow; left unmodified\n",
255 		    in);
256 			eval = 2;
257 			if (unlink(out))
258 				cwarn("%s", out);
259 			goto err;
260 		}
261 
262 		setfile(out, &isb);
263 
264 		if (unlink(in))
265 			cwarn("%s", in);
266 
267 		if (verbose) {
268 			(void)fprintf(stderr, "%s: ", out);
269 			if (isb.st_size > sb.st_size)
270 				(void)fprintf(stderr, "%.0f%% compression\n",
271 				    ((float)sb.st_size / isb.st_size) * 100.0);
272 			else
273 				(void)fprintf(stderr, "%.0f%% expansion\n",
274 				    ((float)isb.st_size / sb.st_size) * 100.0);
275 		}
276 	}
277 	return;
278 
279 err:	if (ofp) {
280 		if (oreg)
281 			(void)unlink(out);
282 		(void)fclose(ofp);
283 	}
284 	if (ifp)
285 		(void)fclose(ifp);
286 }
287 
288 void
289 decompress(const char *in, const char *out, int bits)
290 {
291 	size_t nr;
292 	struct stat sb;
293 	FILE *ifp, *ofp;
294 	int exists, isreg, oreg;
295 	u_char buf[1024];
296 
297 	exists = !stat(out, &sb);
298 	if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
299 		return;
300 	isreg = oreg = !exists || S_ISREG(sb.st_mode);
301 
302 	ifp = ofp = NULL;
303 	if ((ifp = zopen(in, "r", bits)) == NULL) {
304 		cwarn("%s", in);
305 		return;
306 	}
307 	if (stat(in, &sb)) {
308 		cwarn("%s", in);
309 		goto err;
310 	}
311 	if (!S_ISREG(sb.st_mode))
312 		isreg = 0;
313 
314 	/*
315 	 * Try to read the first few uncompressed bytes from the input file
316 	 * before blindly truncating the output file.
317 	 */
318 	if ((nr = fread(buf, 1, sizeof(buf), ifp)) == 0) {
319 		cwarn("%s", in);
320 		(void)fclose(ifp);
321 		return;
322 	}
323 	if ((ofp = fopen(out, "w")) == NULL ||
324 	    (nr != 0 && fwrite(buf, 1, nr, ofp) != nr)) {
325 		cwarn("%s", out);
326 		(void)fclose(ifp);
327 		return;
328 	}
329 
330 	while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
331 		if (fwrite(buf, 1, nr, ofp) != nr) {
332 			cwarn("%s", out);
333 			goto err;
334 		}
335 
336 	if (ferror(ifp) || fclose(ifp)) {
337 		cwarn("%s", in);
338 		goto err;
339 	}
340 	ifp = NULL;
341 
342 	if (fclose(ofp)) {
343 		cwarn("%s", out);
344 		goto err;
345 	}
346 
347 	if (isreg) {
348 		setfile(out, &sb);
349 
350 		if (unlink(in))
351 			cwarn("%s", in);
352 	}
353 	return;
354 
355 err:	if (ofp) {
356 		if (oreg)
357 			(void)unlink(out);
358 		(void)fclose(ofp);
359 	}
360 	if (ifp)
361 		(void)fclose(ifp);
362 }
363 
364 void
365 setfile(const char *name, struct stat *fs)
366 {
367 	static struct timeval tv[2];
368 
369 	fs->st_mode &= S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO;
370 
371 	TIMESPEC_TO_TIMEVAL(&tv[0], &fs->st_atim);
372 	TIMESPEC_TO_TIMEVAL(&tv[1], &fs->st_mtim);
373 	if (utimes(name, tv))
374 		cwarn("utimes: %s", name);
375 
376 	/*
377 	 * Changing the ownership probably won't succeed, unless we're root
378 	 * or POSIX_CHOWN_RESTRICTED is not set.  Set uid/gid before setting
379 	 * the mode; current BSD behavior is to remove all setuid bits on
380 	 * chown.  If chown fails, lose setuid/setgid bits.
381 	 */
382 	if (chown(name, fs->st_uid, fs->st_gid)) {
383 		if (errno != EPERM)
384 			cwarn("chown: %s", name);
385 		fs->st_mode &= ~(S_ISUID|S_ISGID);
386 	}
387 	if (chmod(name, fs->st_mode) && errno != EOPNOTSUPP)
388 		cwarn("chmod: %s", name);
389 
390 	if (chflags(name, fs->st_flags) && errno != EOPNOTSUPP)
391 		cwarn("chflags: %s", name);
392 }
393 
394 int
395 permission(const char *fname)
396 {
397 	int ch, first;
398 
399 	if (!isatty(fileno(stderr)))
400 		return (0);
401 	(void)fprintf(stderr, "overwrite %s? ", fname);
402 	first = ch = getchar();
403 	while (ch != '\n' && ch != EOF)
404 		ch = getchar();
405 	return (first == 'y');
406 }
407 
408 void
409 usage(int iscompress)
410 {
411 	if (iscompress)
412 		(void)fprintf(stderr,
413 		    "usage: compress [-cfv] [-b bits] [file ...]\n");
414 	else
415 		(void)fprintf(stderr,
416 		    "usage: uncompress [-c] [-b bits] [file ...]\n");
417 	exit(1);
418 }
419 
420 void
421 cwarnx(const char *fmt, ...)
422 {
423 	va_list ap;
424 
425 	va_start(ap, fmt);
426 	vwarnx(fmt, ap);
427 	va_end(ap);
428 	eval = 1;
429 }
430 
431 void
432 cwarn(const char *fmt, ...)
433 {
434 	va_list ap;
435 
436 	va_start(ap, fmt);
437 	vwarn(fmt, ap);
438 	va_end(ap);
439 	eval = 1;
440 }
441