xref: /freebsd/usr.bin/compress/compress.c (revision 1aaed33edb24c98a09130cd66667d6a795b6b2a8)
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  * 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 #ifndef lint
31 static const char copyright[] =
32 "@(#) Copyright (c) 1992, 1993\n\
33 	The Regents of the University of California.  All rights reserved.\n";
34 #endif
35 
36 #if 0
37 #ifndef lint
38 static char sccsid[] = "@(#)compress.c	8.2 (Berkeley) 1/7/94";
39 #endif
40 #endif
41 
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
44 
45 #include <sys/param.h>
46 #include <sys/stat.h>
47 #include <sys/time.h>
48 
49 #include <err.h>
50 #include <errno.h>
51 #include <stdarg.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <unistd.h>
56 
57 #include "zopen.h"
58 
59 static void	compress(const char *, const char *, int);
60 static void	cwarn(const char *, ...) __printflike(1, 2);
61 static void	cwarnx(const char *, ...) __printflike(1, 2);
62 static void	decompress(const char *, const char *, int);
63 static int	permission(const char *);
64 static void	setfile(const char *, struct stat *);
65 static void	usage(int);
66 
67 static int eval, force, verbose;
68 
69 int
70 main(int argc, char *argv[])
71 {
72 	enum {COMPRESS, DECOMPRESS} style;
73 	size_t len;
74 	int bits, cat, ch;
75 	char *p, newname[MAXPATHLEN];
76 
77 	cat = 0;
78 	if ((p = strrchr(argv[0], '/')) == NULL)
79 		p = argv[0];
80 	else
81 		++p;
82 	if (!strcmp(p, "uncompress"))
83 		style = DECOMPRESS;
84 	else if (!strcmp(p, "compress"))
85 		style = COMPRESS;
86 	else if (!strcmp(p, "zcat")) {
87 		cat = 1;
88 		style = DECOMPRESS;
89 	} else
90 		errx(1, "unknown program name");
91 
92 	bits = 0;
93 	while ((ch = getopt(argc, argv, "b:cdfv")) != -1)
94 		switch(ch) {
95 		case 'b':
96 			bits = strtol(optarg, &p, 10);
97 			if (*p)
98 				errx(1, "illegal bit count -- %s", optarg);
99 			break;
100 		case 'c':
101 			cat = 1;
102 			break;
103 		case 'd':		/* Backward compatible. */
104 			style = DECOMPRESS;
105 			break;
106 		case 'f':
107 			force = 1;
108 			break;
109 		case 'v':
110 			verbose = 1;
111 			break;
112 		case '?':
113 		default:
114 			usage(style == COMPRESS);
115 		}
116 	argc -= optind;
117 	argv += optind;
118 
119 	if (argc == 0) {
120 		switch(style) {
121 		case COMPRESS:
122 			(void)compress("/dev/stdin", "/dev/stdout", bits);
123 			break;
124 		case DECOMPRESS:
125 			(void)decompress("/dev/stdin", "/dev/stdout", bits);
126 			break;
127 		}
128 		exit (eval);
129 	}
130 
131 	if (cat == 1 && argc > 1)
132 		errx(1, "the -c option permits only a single file argument");
133 
134 	for (; *argv; ++argv)
135 		switch(style) {
136 		case COMPRESS:
137 			if (strcmp(*argv, "-") == 0) {
138 				compress("/dev/stdin", "/dev/stdout", bits);
139 				break;
140 			} else if (cat) {
141 				compress(*argv, "/dev/stdout", bits);
142 				break;
143 			}
144 			if ((p = strrchr(*argv, '.')) != NULL &&
145 			    !strcmp(p, ".Z")) {
146 				cwarnx("%s: name already has trailing .Z",
147 				    *argv);
148 				break;
149 			}
150 			len = strlen(*argv);
151 			if (len > sizeof(newname) - 3) {
152 				cwarnx("%s: name too long", *argv);
153 				break;
154 			}
155 			memmove(newname, *argv, len);
156 			newname[len] = '.';
157 			newname[len + 1] = 'Z';
158 			newname[len + 2] = '\0';
159 			compress(*argv, newname, bits);
160 			break;
161 		case DECOMPRESS:
162 			if (strcmp(*argv, "-") == 0) {
163 				decompress("/dev/stdin", "/dev/stdout", bits);
164 				break;
165 			}
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 			} else {
180 				if (len - 2 > sizeof(newname) - 1) {
181 					cwarnx("%s: name too long", *argv);
182 					break;
183 				}
184 				memmove(newname, *argv, len - 2);
185 				newname[len - 2] = '\0';
186 				decompress(*argv,
187 				    cat ? "/dev/stdout" : newname, bits);
188 			}
189 			break;
190 		}
191 	exit (eval);
192 }
193 
194 static void
195 compress(const char *in, const char *out, int bits)
196 {
197 	size_t nr;
198 	struct stat isb, sb;
199 	FILE *ifp, *ofp;
200 	int exists, isreg, oreg;
201 	u_char buf[1024];
202 
203 	exists = !stat(out, &sb);
204 	if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
205 		return;
206 	isreg = oreg = !exists || S_ISREG(sb.st_mode);
207 
208 	ifp = ofp = NULL;
209 	if ((ifp = fopen(in, "r")) == NULL) {
210 		cwarn("%s", in);
211 		return;
212 	}
213 	if (stat(in, &isb)) {		/* DON'T FSTAT! */
214 		cwarn("%s", in);
215 		goto err;
216 	}
217 	if (!S_ISREG(isb.st_mode))
218 		isreg = 0;
219 
220 	if ((ofp = zopen(out, "w", bits)) == NULL) {
221 		cwarn("%s", out);
222 		goto err;
223 	}
224 	while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
225 		if (fwrite(buf, 1, nr, ofp) != nr) {
226 			cwarn("%s", out);
227 			goto err;
228 		}
229 
230 	if (ferror(ifp) || fclose(ifp)) {
231 		cwarn("%s", in);
232 		goto err;
233 	}
234 	ifp = NULL;
235 
236 	if (fclose(ofp)) {
237 		cwarn("%s", out);
238 		goto err;
239 	}
240 	ofp = NULL;
241 
242 	if (isreg) {
243 		if (stat(out, &sb)) {
244 			cwarn("%s", out);
245 			goto err;
246 		}
247 
248 		if (!force && sb.st_size >= isb.st_size) {
249 			if (verbose)
250 		(void)fprintf(stderr, "%s: file would grow; left unmodified\n",
251 		    in);
252 			eval = 2;
253 			if (unlink(out))
254 				cwarn("%s", out);
255 			goto err;
256 		}
257 
258 		setfile(out, &isb);
259 
260 		if (unlink(in))
261 			cwarn("%s", in);
262 
263 		if (verbose) {
264 			(void)fprintf(stderr, "%s: ", out);
265 			if (isb.st_size > sb.st_size)
266 				(void)fprintf(stderr, "%.0f%% compression\n",
267 				    ((float)sb.st_size / isb.st_size) * 100.0);
268 			else
269 				(void)fprintf(stderr, "%.0f%% expansion\n",
270 				    ((float)isb.st_size / sb.st_size) * 100.0);
271 		}
272 	}
273 	return;
274 
275 err:	if (ofp) {
276 		if (oreg)
277 			(void)unlink(out);
278 		(void)fclose(ofp);
279 	}
280 	if (ifp)
281 		(void)fclose(ifp);
282 }
283 
284 static void
285 decompress(const char *in, const char *out, int bits)
286 {
287 	size_t nr;
288 	struct stat sb;
289 	FILE *ifp, *ofp;
290 	int exists, isreg, oreg;
291 	u_char buf[1024];
292 
293 	exists = !stat(out, &sb);
294 	if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
295 		return;
296 	isreg = oreg = !exists || S_ISREG(sb.st_mode);
297 
298 	ifp = ofp = NULL;
299 	if ((ifp = zopen(in, "r", bits)) == NULL) {
300 		cwarn("%s", in);
301 		return;
302 	}
303 	if (stat(in, &sb)) {
304 		cwarn("%s", in);
305 		goto err;
306 	}
307 	if (!S_ISREG(sb.st_mode))
308 		isreg = 0;
309 
310 	/*
311 	 * Try to read the first few uncompressed bytes from the input file
312 	 * before blindly truncating the output file.
313 	 */
314 	if ((nr = fread(buf, 1, sizeof(buf), ifp)) == 0) {
315 		cwarn("%s", in);
316 		(void)fclose(ifp);
317 		return;
318 	}
319 	if ((ofp = fopen(out, "w")) == NULL ||
320 	    (nr != 0 && fwrite(buf, 1, nr, ofp) != nr)) {
321 		cwarn("%s", out);
322 		(void)fclose(ifp);
323 		return;
324 	}
325 
326 	while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
327 		if (fwrite(buf, 1, nr, ofp) != nr) {
328 			cwarn("%s", out);
329 			goto err;
330 		}
331 
332 	if (ferror(ifp) || fclose(ifp)) {
333 		cwarn("%s", in);
334 		goto err;
335 	}
336 	ifp = NULL;
337 
338 	if (fclose(ofp)) {
339 		cwarn("%s", out);
340 		goto err;
341 	}
342 
343 	if (isreg) {
344 		setfile(out, &sb);
345 
346 		if (unlink(in))
347 			cwarn("%s", in);
348 	}
349 	return;
350 
351 err:	if (ofp) {
352 		if (oreg)
353 			(void)unlink(out);
354 		(void)fclose(ofp);
355 	}
356 	if (ifp)
357 		(void)fclose(ifp);
358 }
359 
360 static void
361 setfile(const char *name, struct stat *fs)
362 {
363 	static struct timeval tv[2];
364 
365 	fs->st_mode &= S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO;
366 
367 	TIMESPEC_TO_TIMEVAL(&tv[0], &fs->st_atim);
368 	TIMESPEC_TO_TIMEVAL(&tv[1], &fs->st_mtim);
369 	if (utimes(name, tv))
370 		cwarn("utimes: %s", name);
371 
372 	/*
373 	 * Changing the ownership probably won't succeed, unless we're root
374 	 * or POSIX_CHOWN_RESTRICTED is not set.  Set uid/gid before setting
375 	 * the mode; current BSD behavior is to remove all setuid bits on
376 	 * chown.  If chown fails, lose setuid/setgid bits.
377 	 */
378 	if (chown(name, fs->st_uid, fs->st_gid)) {
379 		if (errno != EPERM)
380 			cwarn("chown: %s", name);
381 		fs->st_mode &= ~(S_ISUID|S_ISGID);
382 	}
383 	if (chmod(name, fs->st_mode) && errno != EOPNOTSUPP)
384 		cwarn("chmod: %s", name);
385 
386 	if (chflags(name, fs->st_flags) && errno != EOPNOTSUPP)
387 		cwarn("chflags: %s", name);
388 }
389 
390 static int
391 permission(const char *fname)
392 {
393 	int ch, first;
394 
395 	if (!isatty(fileno(stderr)))
396 		return (0);
397 	(void)fprintf(stderr, "overwrite %s? ", fname);
398 	first = ch = getchar();
399 	while (ch != '\n' && ch != EOF)
400 		ch = getchar();
401 	return (first == 'y');
402 }
403 
404 static void
405 usage(int iscompress)
406 {
407 	if (iscompress)
408 		(void)fprintf(stderr,
409 		    "usage: compress [-cfv] [-b bits] [file ...]\n");
410 	else
411 		(void)fprintf(stderr,
412 		    "usage: uncompress [-c] [-b bits] [file ...]\n");
413 	exit(1);
414 }
415 
416 static void
417 cwarnx(const char *fmt, ...)
418 {
419 	va_list ap;
420 
421 	va_start(ap, fmt);
422 	vwarnx(fmt, ap);
423 	va_end(ap);
424 	eval = 1;
425 }
426 
427 static void
428 cwarn(const char *fmt, ...)
429 {
430 	va_list ap;
431 
432 	va_start(ap, fmt);
433 	vwarn(fmt, ap);
434 	va_end(ap);
435 	eval = 1;
436 }
437