aboutsummaryrefslogtreecommitdiffstats
path: root/examples/minitar/minitar.c
blob: 0b4b4147ca99eb3b1e2c4f77ffe345480a39f442 (plain) (blame)
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
/*-
 * This file is in the public domain.
 * Do with it as you will.
 */

/*-
 * This is a compact "tar" program whose primary goal is small size.
 * Statically linked, it can be very small indeed.  This serves a number
 * of goals:
 *   o a testbed for libarchive (to check for link pollution),
 *   o a useful tool for space-constrained systems (boot floppies, etc),
 *   o a place to experiment with new implementation ideas for bsdtar,
 *   o a small program to demonstrate libarchive usage.
 *
 * Use the following macros to suppress features:
 *   NO_BZIP2 - Implies NO_BZIP2_CREATE and NO_BZIP2_EXTRACT
 *   NO_BZIP2_CREATE - Suppress bzip2 compression support.
 *   NO_BZIP2_EXTRACT - Suppress bzip2 auto-detection and decompression.
 *   NO_COMPRESS - Implies NO_COMPRESS_CREATE and NO_COMPRESS_EXTRACT
 *   NO_COMPRESS_CREATE - Suppress compress(1) compression support
 *   NO_COMPRESS_EXTRACT - Suppress compress(1) auto-detect and decompression.
 *   NO_CREATE - Suppress all archive creation support.
 *   NO_CPIO_EXTRACT - Suppress auto-detect and dearchiving of cpio archives.
 *   NO_GZIP - Implies NO_GZIP_CREATE and NO_GZIP_EXTRACT
 *   NO_GZIP_CREATE - Suppress gzip compression support.
 *   NO_GZIP_EXTRACT - Suppress gzip auto-detection and decompression.
 *   NO_LOOKUP - Try to avoid getpw/getgr routines, which can be very large
 *   NO_TAR_EXTRACT - Suppress tar extraction
 *
 * With all of the above macros defined (except NO_TAR_EXTRACT), you
 * get a very small program that can recognize and extract essentially
 * any uncompressed tar archive.  On FreeBSD 5.1, this minimal program
 * is under 64k, statically linked, which compares rather favorably to
 *         main(){printf("hello, world");}
 * which is over 60k statically linked on the same operating system.
 * Without any of the above macros, you get a static executable of
 * about 180k with a lot of very sophisticated modern features.
 * Obviously, it's trivial to add support for ISO, Zip, mtree,
 * lzma/xz, etc.  Just fill in the appropriate setup calls.
 */

#include <sys/types.h>
#include <sys/stat.h>

#include <archive.h>
#include <archive_entry.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

/*
 * NO_CREATE implies NO_BZIP2_CREATE and NO_GZIP_CREATE and NO_COMPRESS_CREATE.
 */
#ifdef NO_CREATE
#undef NO_BZIP2_CREATE
#define NO_BZIP2_CREATE
#undef NO_COMPRESS_CREATE
#define	NO_COMPRESS_CREATE
#undef NO_GZIP_CREATE
#define NO_GZIP_CREATE
#endif

/*
 * The combination of NO_BZIP2_CREATE and NO_BZIP2_EXTRACT is
 * equivalent to NO_BZIP2.
 */
#ifdef NO_BZIP2_CREATE
#ifdef NO_BZIP2_EXTRACT
#undef NO_BZIP2
#define NO_BZIP2
#endif
#endif

#ifdef NO_BZIP2
#undef NO_BZIP2_EXTRACT
#define NO_BZIP2_EXTRACT
#undef NO_BZIP2_CREATE
#define NO_BZIP2_CREATE
#endif

/*
 * The combination of NO_COMPRESS_CREATE and NO_COMPRESS_EXTRACT is
 * equivalent to NO_COMPRESS.
 */
#ifdef NO_COMPRESS_CREATE
#ifdef NO_COMPRESS_EXTRACT
#undef NO_COMPRESS
#define NO_COMPRESS
#endif
#endif

#ifdef NO_COMPRESS
#undef NO_COMPRESS_EXTRACT
#define NO_COMPRESS_EXTRACT
#undef NO_COMPRESS_CREATE
#define NO_COMPRESS_CREATE
#endif

/*
 * The combination of NO_GZIP_CREATE and NO_GZIP_EXTRACT is
 * equivalent to NO_GZIP.
 */
#ifdef NO_GZIP_CREATE
#ifdef NO_GZIP_EXTRACT
#undef NO_GZIP
#define NO_GZIP
#endif
#endif

#ifdef NO_GZIP
#undef NO_GZIP_EXTRACT
#define NO_GZIP_EXTRACT
#undef NO_GZIP_CREATE
#define NO_GZIP_CREATE
#endif

#ifndef NO_CREATE
static void	create(const char *filename, int compress, const char **argv);
#endif
static void	errmsg(const char *);
static void	extract(const char *filename, int do_extract, int flags);
static int	copy_data(struct archive *, struct archive *);
static void	msg(const char *);
static void	usage(void);

static int verbose = 0;

int
main(int argc, const char **argv)
{
	const char *filename = NULL;
	int compress, flags, mode, opt;

	(void)argc;
	mode = 'x';
	verbose = 0;
	compress = '\0';
	flags = ARCHIVE_EXTRACT_TIME;

	/* Among other sins, getopt(3) pulls in printf(3). */
	while (*++argv != NULL && **argv == '-') {
		const char *p = *argv + 1;

		while ((opt = *p++) != '\0') {
			switch (opt) {
#ifndef NO_CREATE
			case 'c':
				mode = opt;
				break;
#endif
			case 'f':
				if (*p != '\0')
					filename = p;
				else
					filename = *++argv;
				p += strlen(p);
				break;
#ifndef NO_BZIP2_CREATE
			case 'j':
				compress = opt;
				break;
#endif
			case 'p':
				flags |= ARCHIVE_EXTRACT_PERM;
				flags |= ARCHIVE_EXTRACT_ACL;
				flags |= ARCHIVE_EXTRACT_FFLAGS;
				break;
			case 't':
				mode = opt;
				break;
			case 'v':
				verbose++;
				break;
			case 'x':
				mode = opt;
				break;
#ifndef NO_BZIP2_CREATE
			case 'y':
				compress = opt;
				break;
#endif
#ifndef NO_COMPRESS_CREATE
			case 'Z':
				compress = opt;
				break;
#endif
#ifndef NO_GZIP_CREATE
			case 'z':
				compress = opt;
				break;
#endif
			default:
				usage();
			}
		}
	}

	switch (mode) {
#ifndef NO_CREATE
	case 'c':
		create(filename, compress, argv);
		break;
#endif
	case 't':
		extract(filename, 0, flags);
		break;
	case 'x':
		extract(filename, 1, flags);
		break;
	}

	return (0);
}


#ifndef NO_CREATE
static char buff[16384];

static void
create(const char *filename, int compress, const char **argv)
{
	struct archive *a;
	struct archive_entry *entry;
	ssize_t len;
	int fd;

	a = archive_write_new();
	switch (compress) {
#ifndef NO_BZIP2_CREATE
	case 'j': case 'y':
		archive_write_add_filter_bzip2(a);
		break;
#endif
#ifndef NO_COMPRESS_CREATE
	case 'Z':
		archive_write_add_filter_compress(a);
		break;
#endif
#ifndef NO_GZIP_CREATE
	case 'z':
		archive_write_add_filter_gzip(a);
		break;
#endif
	default:
		archive_write_add_filter_none(a);
		break;
	}
	archive_write_set_format_ustar(a);
	if (filename != NULL && strcmp(filename, "-") == 0)
		filename = NULL;
	archive_write_open_filename(a, filename);

	while (*argv != NULL) {
		struct archive *disk = archive_read_disk_new();
#ifndef NO_LOOKUP
		archive_read_disk_set_standard_lookup(disk);
#endif
		int r;

		r = archive_read_disk_open(disk, *argv);
		if (r != ARCHIVE_OK) {
			errmsg(archive_error_string(disk));
			errmsg("\n");
			exit(1);
		}

		for (;;) {
			int needcr = 0;

			entry = archive_entry_new();
			r = archive_read_next_header2(disk, entry);
			if (r == ARCHIVE_EOF)
				break;
			if (r != ARCHIVE_OK) {
				errmsg(archive_error_string(disk));
				errmsg("\n");
				exit(1);
			}
			archive_read_disk_descend(disk);
			if (verbose) {
				msg("a ");
				msg(archive_entry_pathname(entry));
				needcr = 1;
			}
			r = archive_write_header(a, entry);
			if (r < ARCHIVE_OK) {
				errmsg(": ");
				errmsg(archive_error_string(a));
				needcr = 1;
			}
			if (r == ARCHIVE_FATAL)
				exit(1);
			if (r > ARCHIVE_FAILED) {
#if 0
				/* Ideally, we would be able to use
				 * the same code to copy a body from
				 * an archive_read_disk to an
				 * archive_write that we use for
				 * copying data from an archive_read
				 * to an archive_write_disk.
				 * Unfortunately, this doesn't quite
				 * work yet. */
				copy_data(disk, a);
#else
				/* For now, we use a simpler loop to copy data
				 * into the target archive. */
				fd = open(archive_entry_sourcepath(entry), O_RDONLY);
				len = read(fd, buff, sizeof(buff));
				while (len > 0) {
					archive_write_data(a, buff, len);
					len = read(fd, buff, sizeof(buff));
				}
				close(fd);
#endif
			}
			archive_entry_free(entry);
			if (needcr)
				msg("\n");
		}
		archive_read_close(disk);
		archive_read_free(disk);
		argv++;
	}
	archive_write_close(a);
	archive_write_free(a);
}
#endif

static void
extract(const char *filename, int do_extract, int flags)
{
	struct archive *a;
	struct archive *ext;
	struct archive_entry *entry;
	int r;

	a = archive_read_new();
	ext = archive_write_disk_new();
	archive_write_disk_set_options(ext, flags);
#ifndef NO_BZIP2_EXTRACT
	archive_read_support_filter_bzip2(a);
#endif
#ifndef NO_GZIP_EXTRACT
	archive_read_support_filter_gzip(a);
#endif
#ifndef NO_COMPRESS_EXTRACT
	archive_read_support_filter_compress(a);
#endif
#ifndef NO_TAR_EXTRACT
	archive_read_support_format_tar(a);
#endif
#ifndef NO_CPIO_EXTRACT
	archive_read_support_format_cpio(a);
#endif
#ifndef NO_LOOKUP
	archive_write_disk_set_standard_lookup(ext);
#endif
	if (filename != NULL && strcmp(filename, "-") == 0)
		filename = NULL;
	if ((r = archive_read_open_filename(a, filename, 10240))) {
		errmsg(archive_error_string(a));
		errmsg("\n");
		exit(r);
	}
	for (;;) {
		int needcr = 0;
		r = archive_read_next_header(a, &entry);
		if (r == ARCHIVE_EOF)
			break;
		if (r != ARCHIVE_OK) {
			errmsg(archive_error_string(a));
			errmsg("\n");
			exit(1);
		}
		if (verbose && do_extract)
			msg("x ");
		if (verbose || !do_extract) {
			msg(archive_entry_pathname(entry));
			msg(" ");
			needcr = 1;
		}
		if (do_extract) {
			r = archive_write_header(ext, entry);
			if (r != ARCHIVE_OK) {
				errmsg(archive_error_string(a));
				needcr = 1;
			}
			else {
				r = copy_data(a, ext);
				if (r != ARCHIVE_OK)
					needcr = 1;
			}
		}
		if (needcr)
			msg("\n");
	}
	archive_read_close(a);
	archive_read_free(a);
	exit(0);
}

static int
copy_data(struct archive *ar, struct archive *aw)
{
	int r;
	const void *buff;
	size_t size;
	int64_t offset;

	for (;;) {
		r = archive_read_data_block(ar, &buff, &size, &offset);
		if (r == ARCHIVE_EOF)
			return (ARCHIVE_OK);
		if (r != ARCHIVE_OK) {
			errmsg(archive_error_string(ar));
			return (r);
		}
		r = archive_write_data_block(aw, buff, size, offset);
		if (r != ARCHIVE_OK) {
			errmsg(archive_error_string(ar));
			return (r);
		}
	}
}

static void
msg(const char *m)
{
	write(1, m, strlen(m));
}

static void
errmsg(const char *m)
{
	if (m == NULL) {
		m = "Error: No error description provided.\n";
	}
	write(2, m, strlen(m));
}

static void
usage(void)
{
/* Many program options depend on compile options. */
	const char *m = "Usage: minitar [-"
#ifndef NO_CREATE
	    "c"
#endif
#ifndef	NO_BZIP2
	    "j"
#endif
	    "tvx"
#ifndef NO_BZIP2
	    "y"
#endif
#ifndef NO_COMPRESS
	    "Z"
#endif
#ifndef NO_GZIP
	    "z"
#endif
	    "] [-f file] [file]\n";

	errmsg(m);
	exit(1);
}