aboutsummaryrefslogtreecommitdiff
path: root/archival/bbunzip.c
blob: 6244bce853e0da9b80254d96ce317da79b7d3e9f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
/* vi: set sw=4 ts=4: */
/*
 * Common code for gunzip-like applets
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
//kbuild:lib-$(CONFIG_ZCAT) += bbunzip.o
//kbuild:lib-$(CONFIG_GUNZIP) += bbunzip.o
//kbuild:lib-$(CONFIG_BZCAT) += bbunzip.o
//kbuild:lib-$(CONFIG_BUNZIP2) += bbunzip.o

/* lzop_main() uses bbunpack(), need this: */
//kbuild:lib-$(CONFIG_LZOP) += bbunzip.o
//kbuild:lib-$(CONFIG_LZOPCAT) += bbunzip.o
//kbuild:lib-$(CONFIG_UNLZOP) += bbunzip.o
/* bzip2_main() too: */
//kbuild:lib-$(CONFIG_BZIP2) += bbunzip.o
/* gzip_main() too: */
//kbuild:lib-$(CONFIG_GZIP) += bbunzip.o

#include "libbb.h"
#include "bb_archive.h"

static
int open_to_or_warn(int to_fd, const char *filename, int flags, int mode)
{
	int fd = open3_or_warn(filename, flags, mode);
	if (fd < 0) {
		return 1;
	}
	xmove_fd(fd, to_fd);
	return 0;
}

char* FAST_FUNC append_ext(char *filename, const char *expected_ext)
{
	return xasprintf("%s.%s", filename, expected_ext);
}

int FAST_FUNC bbunpack(char **argv,
	IF_DESKTOP(long long) int FAST_FUNC (*unpacker)(transformer_state_t *xstate),
	char* FAST_FUNC (*make_new_name)(char *filename, const char *expected_ext),
	const char *expected_ext
)
{
	struct stat stat_buf;
	IF_DESKTOP(long long) int status = 0;
	char *filename, *new_name;
	smallint exitcode = 0;
	transformer_state_t xstate;

	do {
		/* NB: new_name is *maybe* malloc'ed! */
		new_name = NULL;
		filename = *argv; /* can be NULL - 'streaming' bunzip2 */

		if (filename && LONE_DASH(filename))
			filename = NULL;

		/* Open src */
		if (filename) {
			if (!(option_mask32 & BBUNPK_SEAMLESS_MAGIC)) {
				if (stat(filename, &stat_buf) != 0) {
 err_name:
					bb_simple_perror_msg(filename);
 err:
					exitcode = 1;
					goto free_name;
				}
				if (open_to_or_warn(STDIN_FILENO, filename, O_RDONLY, 0))
					goto err;
			} else {
				/* "clever zcat" with FILE */
				/* fail_if_not_compressed because zcat refuses uncompressed input */
				int fd = open_zipped(filename, /*fail_if_not_compressed:*/ 1);
				if (fd < 0)
					goto err_name;
				xmove_fd(fd, STDIN_FILENO);
			}
		} else
		if (option_mask32 & BBUNPK_SEAMLESS_MAGIC) {
			/* "clever zcat" on stdin */
			if (setup_unzip_on_fd(STDIN_FILENO, /*fail_if_not_compressed*/ 1))
				goto err;
		}

		/* Special cases: test, stdout */
		if (option_mask32 & (BBUNPK_OPT_STDOUT|BBUNPK_OPT_TEST)) {
			if (option_mask32 & BBUNPK_OPT_TEST)
				if (open_to_or_warn(STDOUT_FILENO, bb_dev_null, O_WRONLY, 0))
					xfunc_die();
			filename = NULL;
		}

		/* Open dst if we are going to unpack to file */
		if (filename) {
			new_name = make_new_name(filename, expected_ext);
			if (!new_name) {
				bb_error_msg("%s: unknown suffix - ignored", filename);
				goto err;
			}

			/* -f: overwrite existing output files */
			if (option_mask32 & BBUNPK_OPT_FORCE) {
				unlink(new_name);
			}

			/* O_EXCL: "real" bunzip2 doesn't overwrite files */
			/* GNU gunzip does not bail out, but goes to next file */
			if (open_to_or_warn(STDOUT_FILENO, new_name, O_WRONLY | O_CREAT | O_EXCL,
					stat_buf.st_mode))
				goto err;
		}

		/* Check that the input is sane */
		if (!(option_mask32 & BBUNPK_OPT_FORCE) && isatty(STDIN_FILENO)) {
			bb_simple_error_msg_and_die("compressed data not read from terminal, "
					"use -f to force it");
		}

		if (!(option_mask32 & BBUNPK_SEAMLESS_MAGIC)) {
			init_transformer_state(&xstate);
			/*xstate.signature_skipped = 0; - already is */
			/*xstate.src_fd = STDIN_FILENO; - already is */
			xstate.dst_fd = STDOUT_FILENO;
			status = unpacker(&xstate);
			if (status < 0)
				exitcode = 1;
		} else {
			if (bb_copyfd_eof(STDIN_FILENO, STDOUT_FILENO) < 0)
				/* Disk full, tty closed, etc. No point in continuing */
				xfunc_die();
		}

		if (!(option_mask32 & BBUNPK_OPT_STDOUT))
			xclose(STDOUT_FILENO); /* with error check! */

		if (filename) {
			char *del = new_name;

			if (status >= 0) {
				unsigned new_name_len;

				/* TODO: restore other things? */
				if (xstate.mtime != 0) {
					struct timeval times[2];

					times[1].tv_sec = times[0].tv_sec = xstate.mtime;
					times[1].tv_usec = times[0].tv_usec = 0;
					/* Note: we closed it first.
					 * On some systems calling utimes
					 * then closing resets the mtime
					 * back to current time. */
					utimes(new_name, times); /* ignoring errors */
				}

				if (ENABLE_DESKTOP)
					new_name_len = strlen(new_name);
				/* Restore source filename (unless tgz -> tar case) */
				if (new_name == filename) {
					new_name_len = strlen(filename);
					filename[new_name_len] = '.';
				}
				/* Extreme bloat for gunzip compat */
				/* Some users do want this info... */
				if (ENABLE_DESKTOP && (option_mask32 & BBUNPK_OPT_VERBOSE)) {
					unsigned percent = status
						? ((uoff_t)stat_buf.st_size * 100u / (unsigned long long)status)
						: 0;
					fprintf(stderr, "%s: %u%% - replaced with %.*s\n",
						filename,
						100u - percent,
						new_name_len, new_name
					);
				}
				/* Delete _source_ file */
				del = filename;
				if (option_mask32 & BBUNPK_OPT_KEEP) /* ... unless -k */
					del = NULL;
			}
			if (del)
				xunlink(del);
 free_name:
			if (new_name != filename)
				free(new_name);
		}
	} while (*argv && *++argv);

	if (option_mask32 & BBUNPK_OPT_STDOUT)
		xclose(STDOUT_FILENO); /* with error check! */

	return exitcode;
}

#if ENABLE_UNCOMPRESS \
 || ENABLE_FEATURE_BZIP2_DECOMPRESS \
 || ENABLE_UNLZMA || ENABLE_LZCAT || ENABLE_LZMA \
 || ENABLE_UNXZ || ENABLE_XZCAT || ENABLE_XZ
static
char* FAST_FUNC make_new_name_generic(char *filename, const char *expected_ext)
{
	char *extension = strrchr(filename, '.');
	if (!extension || strcmp(extension + 1, expected_ext) != 0) {
		/* Mimic GNU gunzip - "real" bunzip2 tries to */
		/* unpack file anyway, to file.out */
		return NULL;
	}
	*extension = '\0';
	return filename;
}
#endif


/*
 * Uncompress applet for busybox (c) 2002 Glenn McGrath
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
//usage:#define uncompress_trivial_usage
//usage:       "[-cf] [FILE]..."
//usage:#define uncompress_full_usage "\n\n"
//usage:       "Decompress .Z file[s]\n"
//usage:     "\n	-c	Write to stdout"
//usage:     "\n	-f	Overwrite"

//config:config UNCOMPRESS
//config:	bool "uncompress (7.1 kb)"
//config:	default n  # ancient
//config:	help
//config:	uncompress is used to decompress archives created by compress.
//config:	Not much used anymore, replaced by gzip/gunzip.

//applet:IF_UNCOMPRESS(APPLET(uncompress, BB_DIR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_UNCOMPRESS) += bbunzip.o
#if ENABLE_UNCOMPRESS
int uncompress_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int uncompress_main(int argc UNUSED_PARAM, char **argv)
{
// (N)compress 4.2.4.4:
// -d If given, decompression is done instead
// -c Write output on stdout, don't remove original
// -b Parameter limits the max number of bits/code
// -f Forces output file to be generated
// -v Write compression statistics
// -V Output vesion and compile options
// -r Recursive. If a filename is a directory, descend into it and compress everything
	getopt32(argv, "cf");

	argv += optind;

	return bbunpack(argv, unpack_Z_stream, make_new_name_generic, "Z");
}
#endif


/*
 * Gzip implementation for busybox
 *
 * Based on GNU gzip v1.2.4 Copyright (C) 1992-1993 Jean-loup Gailly.
 *
 * Originally adjusted for busybox by Sven Rudolph <sr1@inf.tu-dresden.de>
 * based on gzip sources
 *
 * Adjusted further by Erik Andersen <andersen@codepoet.org> to support files as
 * well as stdin/stdout, and to generally behave itself wrt command line
 * handling.
 *
 * General cleanup to better adhere to the style guide and make use of standard
 * busybox functions by Glenn McGrath
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 *
 * gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * The unzip code was written and put in the public domain by Mark Adler.
 * Portions of the lzw code are derived from the public domain 'compress'
 * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
 * Ken Turkowski, Dave Mack and Peter Jannesen.
 */
//usage:#define gunzip_trivial_usage
//usage:       "[-cfkt] [FILE]..."
//usage:#define gunzip_full_usage "\n\n"
//usage:       "Decompress FILEs (or stdin)\n"
//usage:     "\n	-c	Write to stdout"
//usage:     "\n	-f	Force"
//usage:     "\n	-k	Keep input files"
//usage:     "\n	-t	Test file integrity"
//usage:
//usage:#define gunzip_example_usage
//usage:       "$ ls -la /tmp/BusyBox*\n"
//usage:       "-rw-rw-r--    1 andersen andersen   557009 Apr 11 10:55 /tmp/BusyBox-0.43.tar.gz\n"
//usage:       "$ gunzip /tmp/BusyBox-0.43.tar.gz\n"
//usage:       "$ ls -la /tmp/BusyBox*\n"
//usage:       "-rw-rw-r--    1 andersen andersen  1761280 Apr 14 17:47 /tmp/BusyBox-0.43.tar\n"
//usage:
//usage:#define zcat_trivial_usage
//usage:       "[FILE]..."
//usage:#define zcat_full_usage "\n\n"
//usage:       "Decompress to stdout"

//config:config GUNZIP
//config:	bool "gunzip (11 kb)"
//config:	default y
//config:	select FEATURE_GZIP_DECOMPRESS
//config:	help
//config:	gunzip is used to decompress archives created by gzip.
//config:	You can use the '-t' option to test the integrity of
//config:	an archive, without decompressing it.
//config:
//config:config ZCAT
//config:	bool "zcat (24 kb)"
//config:	default y
//config:	select FEATURE_GZIP_DECOMPRESS
//config:	help
//config:	Alias to "gunzip -c".
//config:
//config:config FEATURE_GUNZIP_LONG_OPTIONS
//config:	bool "Enable long options"
//config:	default y
//config:	depends on (GUNZIP || ZCAT) && LONG_OPTS

//applet:IF_GUNZIP(APPLET(gunzip, BB_DIR_BIN, BB_SUID_DROP))
//               APPLET_ODDNAME:name  main    location    suid_type     help
//applet:IF_ZCAT(APPLET_ODDNAME(zcat, gunzip, BB_DIR_BIN, BB_SUID_DROP, zcat))
#if ENABLE_FEATURE_GZIP_DECOMPRESS
static
char* FAST_FUNC make_new_name_gunzip(char *filename, const char *expected_ext UNUSED_PARAM)
{
	char *extension = strrchr(filename, '.');

	if (!extension)
		return NULL;

	extension++;
	if (strcmp(extension, "tgz" + 1) == 0
#if ENABLE_FEATURE_SEAMLESS_Z
	 || (extension[0] == 'Z' && extension[1] == '\0')
#endif
	) {
		extension[-1] = '\0';
	} else if (strcmp(extension, "tgz") == 0) {
		filename = xstrdup(filename);
		extension = strrchr(filename, '.');
		extension[2] = 'a';
		extension[3] = 'r';
	} else {
		return NULL;
	}
	return filename;
}

#if ENABLE_FEATURE_GUNZIP_LONG_OPTIONS
static const char gunzip_longopts[] ALIGN1 =
	"stdout\0"              No_argument       "c"
	"to-stdout\0"           No_argument       "c"
	"force\0"               No_argument       "f"
	"test\0"                No_argument       "t"
	"no-name\0"             No_argument       "n"
	;
#endif

/*
 * Linux kernel build uses gzip -d -n. We accept and ignore it.
 * Man page says:
 * -n --no-name
 * gzip: do not save the original file name and time stamp.
 * (The original name is always saved if the name had to be truncated.)
 * gunzip: do not restore the original file name/time even if present
 * (remove only the gzip suffix from the compressed file name).
 * This option is the default when decompressing.
 * -N --name
 * gzip: always save the original file name and time stamp (this is the default)
 * gunzip: restore the original file name and time stamp if present.
 */
int gunzip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int gunzip_main(int argc UNUSED_PARAM, char **argv)
{
#if ENABLE_FEATURE_GUNZIP_LONG_OPTIONS
	getopt32long(argv, BBUNPK_OPTSTR "dtn", gunzip_longopts);
#else
	getopt32(argv, BBUNPK_OPTSTR "dtn");
#endif
	argv += optind;

	/* If called as zcat...
	 * Normally, "zcat" is just "gunzip -c".
	 * But if seamless magic is enabled, then we are much more clever.
	 */
	if (ENABLE_ZCAT && applet_name[1] == 'c')
		option_mask32 |= BBUNPK_OPT_STDOUT | BBUNPK_SEAMLESS_MAGIC;

	return bbunpack(argv, unpack_gz_stream, make_new_name_gunzip, /*unused:*/ NULL);
}
#endif /* FEATURE_GZIP_DECOMPRESS */


/*
 * Modified for busybox by Glenn McGrath
 * Added support output to stdout by Thomas Lundquist <thomasez@zelow.no>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
//usage:#define bunzip2_trivial_usage
//usage:       "[-cfk] [FILE]..."
//usage:#define bunzip2_full_usage "\n\n"
//usage:       "Decompress FILEs (or stdin)\n"
//usage:     "\n	-c	Write to stdout"
//usage:     "\n	-f	Force"
//usage:     "\n	-k	Keep input files"
//usage:#define bzcat_trivial_usage
//usage:       "[FILE]..."
//usage:#define bzcat_full_usage "\n\n"
//usage:       "Decompress to stdout"

//config:config BUNZIP2
//config:	bool "bunzip2 (8.7 kb)"
//config:	default y
//config:	select FEATURE_BZIP2_DECOMPRESS
//config:	help
//config:	bunzip2 is a compression utility using the Burrows-Wheeler block
//config:	sorting text compression algorithm, and Huffman coding. Compression
//config:	is generally considerably better than that achieved by more
//config:	conventional LZ77/LZ78-based compressors, and approaches the
//config:	performance of the PPM family of statistical compressors.
//config:
//config:	Unless you have a specific application which requires bunzip2, you
//config:	should probably say N here.
//config:
//config:config BZCAT
//config:	bool "bzcat (8.7 kb)"
//config:	default y
//config:	select FEATURE_BZIP2_DECOMPRESS
//config:	help
//config:	Alias to "bunzip2 -c".

//applet:IF_BUNZIP2(APPLET(bunzip2, BB_DIR_USR_BIN, BB_SUID_DROP))
//                APPLET_ODDNAME:name   main     location        suid_type     help
//applet:IF_BZCAT(APPLET_ODDNAME(bzcat, bunzip2, BB_DIR_USR_BIN, BB_SUID_DROP, bzcat))
#if ENABLE_FEATURE_BZIP2_DECOMPRESS || ENABLE_BUNZIP2 || ENABLE_BZCAT
int bunzip2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int bunzip2_main(int argc UNUSED_PARAM, char **argv)
{
	getopt32(argv, BBUNPK_OPTSTR "dt");
	argv += optind;
	if (ENABLE_BZCAT && (!ENABLE_BUNZIP2 || applet_name[2] == 'c')) /* bzcat */
		option_mask32 |= BBUNPK_OPT_STDOUT;

	return bbunpack(argv, unpack_bz2_stream, make_new_name_generic, "bz2");
}
#endif


/*
 * Small lzma deflate implementation.
 * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
 *
 * Based on bunzip.c from busybox
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
//usage:#define unlzma_trivial_usage
//usage:       "[-cfk] [FILE]..."
//usage:#define unlzma_full_usage "\n\n"
//usage:       "Decompress FILE (or stdin)\n"
//usage:     "\n	-c	Write to stdout"
//usage:     "\n	-f	Force"
//usage:     "\n	-k	Keep input files"
//usage:
//usage:#define lzma_trivial_usage
//usage:       "-d [-cfk] [FILE]..."
//usage:#define lzma_full_usage "\n\n"
//usage:       "Decompress FILE (or stdin)\n"
//usage:     "\n	-d	Decompress"
//usage:     "\n	-c	Write to stdout"
//usage:     "\n	-f	Force"
//usage:     "\n	-k	Keep input files"
//usage:
//usage:#define lzcat_trivial_usage
//usage:       "[FILE]..."
//usage:#define lzcat_full_usage "\n\n"
//usage:       "Decompress to stdout"

//config:config UNLZMA
//config:	bool "unlzma (7.5 kb)"
//config:	default y
//config:	help
//config:	unlzma is a compression utility using the Lempel-Ziv-Markov chain
//config:	compression algorithm, and range coding. Compression
//config:	is generally considerably better than that achieved by the bzip2
//config:	compressors.
//config:
//config:config LZCAT
//config:	bool "lzcat (7.5 kb)"
//config:	default y
//config:	help
//config:	Alias to "unlzma -c".
//config:
//config:config LZMA
//config:	bool "lzma -d"
//config:	default y
//config:	help
//config:	Enable this option if you want commands like "lzma -d" to work.
//config:	IOW: you'll get lzma applet, but it will always require -d option.

//applet:IF_UNLZMA(APPLET(unlzma, BB_DIR_USR_BIN, BB_SUID_DROP))
//                APPLET_ODDNAME:name   main    location        suid_type     help
//applet:IF_LZCAT(APPLET_ODDNAME(lzcat, unlzma, BB_DIR_USR_BIN, BB_SUID_DROP, lzcat))
//applet:IF_LZMA( APPLET_ODDNAME(lzma,  unlzma, BB_DIR_USR_BIN, BB_SUID_DROP, lzma))
//kbuild:lib-$(CONFIG_UNLZMA) += bbunzip.o
//kbuild:lib-$(CONFIG_LZCAT) += bbunzip.o
//kbuild:lib-$(CONFIG_LZMA) += bbunzip.o
#if ENABLE_UNLZMA || ENABLE_LZCAT || ENABLE_LZMA
int unlzma_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int unlzma_main(int argc UNUSED_PARAM, char **argv)
{
	IF_LZMA(int opts =) getopt32(argv, BBUNPK_OPTSTR "dt");
# if ENABLE_LZMA
	/* lzma without -d or -t? */
	if (applet_name[2] == 'm' && !(opts & (BBUNPK_OPT_DECOMPRESS|BBUNPK_OPT_TEST)))
		bb_show_usage();
# endif
	/* lzcat? */
	if (ENABLE_LZCAT && applet_name[2] == 'c')
		option_mask32 |= BBUNPK_OPT_STDOUT;

	argv += optind;
	return bbunpack(argv, unpack_lzma_stream, make_new_name_generic, "lzma");
}
#endif


//usage:#define unxz_trivial_usage
//usage:       "[-cfk] [FILE]..."
//usage:#define unxz_full_usage "\n\n"
//usage:       "Decompress FILE (or stdin)\n"
//usage:     "\n	-c	Write to stdout"
//usage:     "\n	-f	Force"
//usage:     "\n	-k	Keep input files"
//usage:     "\n	-t	Test file integrity"
//usage:
//usage:#define xz_trivial_usage
//usage:       "-d [-cfk] [FILE]..."
//usage:#define xz_full_usage "\n\n"
//usage:       "Decompress FILE (or stdin)\n"
//usage:     "\n	-d	Decompress"
//usage:     "\n	-c	Write to stdout"
//usage:     "\n	-f	Force"
//usage:     "\n	-k	Keep input files"
//usage:     "\n	-t	Test file integrity"
//usage:
//usage:#define xzcat_trivial_usage
//usage:       "[FILE]..."
//usage:#define xzcat_full_usage "\n\n"
//usage:       "Decompress to stdout"

//config:config UNXZ
//config:	bool "unxz (13 kb)"
//config:	default y
//config:	help
//config:	unxz is a unlzma successor.
//config:
//config:config XZCAT
//config:	bool "xzcat (13 kb)"
//config:	default y
//config:	help
//config:	Alias to "unxz -c".
//config:
//config:config XZ
//config:	bool "xz -d"
//config:	default y
//config:	help
//config:	Enable this option if you want commands like "xz -d" to work.
//config:	IOW: you'll get xz applet, but it will always require -d option.

//applet:IF_UNXZ(APPLET(unxz, BB_DIR_USR_BIN, BB_SUID_DROP))
//                APPLET_ODDNAME:name   main  location        suid_type     help
//applet:IF_XZCAT(APPLET_ODDNAME(xzcat, unxz, BB_DIR_USR_BIN, BB_SUID_DROP, xzcat))
//applet:IF_XZ(   APPLET_ODDNAME(xz,    unxz, BB_DIR_USR_BIN, BB_SUID_DROP, xz))
//kbuild:lib-$(CONFIG_UNXZ) += bbunzip.o
//kbuild:lib-$(CONFIG_XZCAT) += bbunzip.o
//kbuild:lib-$(CONFIG_XZ) += bbunzip.o
#if ENABLE_UNXZ || ENABLE_XZCAT || ENABLE_XZ
int unxz_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int unxz_main(int argc UNUSED_PARAM, char **argv)
{
	IF_XZ(int opts =) getopt32(argv, BBUNPK_OPTSTR "dt");
# if ENABLE_XZ
	/* xz without -d or -t? */
	if (applet_name[2] == '\0' && !(opts & (BBUNPK_OPT_DECOMPRESS|BBUNPK_OPT_TEST)))
		bb_show_usage();
# endif
	/* xzcat? */
	if (ENABLE_XZCAT && applet_name[2] == 'c')
		option_mask32 |= BBUNPK_OPT_STDOUT;

	argv += optind;
	return bbunpack(argv, unpack_xz_stream, make_new_name_generic, "xz");
}
#endif