summaryrefslogtreecommitdiff
path: root/archival/unzip.c
blob: 1c9bc246c71accea6652db50fcc794c80c7df53e (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
/* vi: set sw=4 ts=4: */
/*
 * Mini unzip implementation for busybox
 *
 * Copyright (C) 2004 by Ed Clark
 *
 * Loosely based on original busybox unzip applet by Laurence Anderson.
 * All options and features should work in this version.
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */

/* For reference see
 * http://www.pkware.com/company/standards/appnote/
 * http://www.info-zip.org/pub/infozip/doc/appnote-iz-latest.zip
 */

/* TODO
 * Endian issues
 * Zip64 + other methods
 * Improve handling of zip format, ie.
 * - deferred CRC, comp. & uncomp. lengths (zip header flags bit 3)
 * - unix file permissions, etc.
 * - central directory
 */

#include "libbb.h"
#include "unarchive.h"

enum {
#if BB_BIG_ENDIAN
	ZIP_FILEHEADER_MAGIC = 0x504b0304,
	ZIP_CDS_MAGIC        = 0x504b0102,
	ZIP_CDS_END_MAGIC    = 0x504b0506,
	ZIP_DD_MAGIC         = 0x504b0708,
#else
	ZIP_FILEHEADER_MAGIC = 0x04034b50,
	ZIP_CDS_MAGIC        = 0x02014b50,
	ZIP_CDS_END_MAGIC    = 0x06054b50,
	ZIP_DD_MAGIC         = 0x08074b50,
#endif
};

#define ZIP_HEADER_LEN 26

typedef union {
	uint8_t raw[ZIP_HEADER_LEN];
	struct {
		uint16_t version;                       /* 0-1 */
		uint16_t flags;                         /* 2-3 */
		uint16_t method;                        /* 4-5 */
		uint16_t modtime;                       /* 6-7 */
		uint16_t moddate;                       /* 8-9 */
		uint32_t crc32 PACKED;        /* 10-13 */
		uint32_t cmpsize PACKED;      /* 14-17 */
		uint32_t ucmpsize PACKED;     /* 18-21 */
		uint16_t filename_len;                  /* 22-23 */
		uint16_t extra_len;                     /* 24-25 */
	} formatted PACKED;
} zip_header_t; /* PACKED - gcc 4.2.1 doesn't like it (spews warning) */

/* Check the offset of the last element, not the length.  This leniency
 * allows for poor packing, whereby the overall struct may be too long,
 * even though the elements are all in the right place.
 */
struct BUG_zip_header_must_be_26_bytes {
	char BUG_zip_header_must_be_26_bytes[
		offsetof(zip_header_t, formatted.extra_len) + 2 ==
			ZIP_HEADER_LEN ? 1 : -1];
};

#define FIX_ENDIANNESS(zip_header) do { \
	(zip_header).formatted.version      = SWAP_LE16((zip_header).formatted.version     ); \
	(zip_header).formatted.flags        = SWAP_LE16((zip_header).formatted.flags       ); \
	(zip_header).formatted.method       = SWAP_LE16((zip_header).formatted.method      ); \
	(zip_header).formatted.modtime      = SWAP_LE16((zip_header).formatted.modtime     ); \
	(zip_header).formatted.moddate      = SWAP_LE16((zip_header).formatted.moddate     ); \
	(zip_header).formatted.crc32        = SWAP_LE32((zip_header).formatted.crc32       ); \
	(zip_header).formatted.cmpsize      = SWAP_LE32((zip_header).formatted.cmpsize     ); \
	(zip_header).formatted.ucmpsize     = SWAP_LE32((zip_header).formatted.ucmpsize    ); \
	(zip_header).formatted.filename_len = SWAP_LE16((zip_header).formatted.filename_len); \
	(zip_header).formatted.extra_len    = SWAP_LE16((zip_header).formatted.extra_len   ); \
} while (0)

static void unzip_skip(int fd, off_t skip)
{
	bb_copyfd_exact_size(fd, -1, skip);
}

static void unzip_create_leading_dirs(const char *fn)
{
	/* Create all leading directories */
	char *name = xstrdup(fn);
	if (bb_make_directory(dirname(name), 0777, FILEUTILS_RECUR)) {
		bb_error_msg_and_die("exiting"); /* bb_make_directory is noisy */
	}
	free(name);
}

static void unzip_extract(zip_header_t *zip_header, int src_fd, int dst_fd)
{
	if (zip_header->formatted.method == 0) {
		/* Method 0 - stored (not compressed) */
		off_t size = zip_header->formatted.ucmpsize;
		if (size)
			bb_copyfd_exact_size(src_fd, dst_fd, size);
	} else {
		/* Method 8 - inflate */
		inflate_unzip_result res;
		if (inflate_unzip(&res, zip_header->formatted.cmpsize, src_fd, dst_fd) < 0)
			bb_error_msg_and_die("inflate error");
		/* Validate decompression - crc */
		if (zip_header->formatted.crc32 != (res.crc ^ 0xffffffffL)) {
			bb_error_msg_and_die("crc error");
		}
		/* Validate decompression - size */
		if (zip_header->formatted.ucmpsize != res.bytes_out) {
			/* Don't die. Who knows, maybe len calculation
			 * was botched somewhere. After all, crc matched! */
			bb_error_msg("bad length");
		}
	}
}

int unzip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int unzip_main(int argc, char **argv)
{
	enum { O_PROMPT, O_NEVER, O_ALWAYS };

	zip_header_t zip_header;
	smallint verbose = 1;
	smallint listing = 0;
	smallint overwrite = O_PROMPT;
	unsigned total_size;
	unsigned total_entries;
	int src_fd = -1;
	int dst_fd = -1;
	char *src_fn = NULL;
	char *dst_fn = NULL;
	llist_t *zaccept = NULL;
	llist_t *zreject = NULL;
	char *base_dir = NULL;
	int i, opt;
	int opt_range = 0;
	char key_buf[80];
	struct stat stat_buf;

	/* '-' makes getopt return 1 for non-options */
	while ((opt = getopt(argc, argv, "-d:lnopqx")) != -1) {
		switch (opt_range) {
		case 0: /* Options */
			switch (opt) {
			case 'l': /* List */
				listing = 1;
				break;

			case 'n': /* Never overwrite existing files */
				overwrite = O_NEVER;
				break;

			case 'o': /* Always overwrite existing files */
				overwrite = O_ALWAYS;
				break;

			case 'p': /* Extract files to stdout and fall through to set verbosity */
				dst_fd = STDOUT_FILENO;

			case 'q': /* Be quiet */
				verbose = 0;
				break;

			case 1: /* The zip file */
				/* +5: space for ".zip" and NUL */
				src_fn = xmalloc(strlen(optarg) + 5);
				strcpy(src_fn, optarg);
				opt_range++;
				break;

			default:
				bb_show_usage();

			}
			break;

		case 1: /* Include files */
			if (opt == 1) {
				llist_add_to(&zaccept, optarg);
				break;
			}
			if (opt == 'd') {
				base_dir = optarg;
				opt_range += 2;
				break;
			}
			if (opt == 'x') {
				opt_range++;
				break;
			}
			bb_show_usage();

		case 2 : /* Exclude files */
			if (opt == 1) {
				llist_add_to(&zreject, optarg);
				break;
			}
			if (opt == 'd') { /* Extract to base directory */
				base_dir = optarg;
				opt_range++;
				break;
			}
			/* fall through */

		default:
			bb_show_usage();
		}
	}

	if (src_fn == NULL) {
		bb_show_usage();
	}

	/* Open input file */
	if (LONE_DASH(src_fn)) {
		src_fd = STDIN_FILENO;
		/* Cannot use prompt mode since zip data is arriving on STDIN */
		if (overwrite == O_PROMPT)
			overwrite = O_NEVER;
	} else {
		static const char extn[][5] = {"", ".zip", ".ZIP"};
		int orig_src_fn_len = strlen(src_fn);

		for (i = 0; (i < 3) && (src_fd == -1); i++) {
			strcpy(src_fn + orig_src_fn_len, extn[i]);
			src_fd = open(src_fn, O_RDONLY);
		}
		if (src_fd == -1) {
			src_fn[orig_src_fn_len] = '\0';
			bb_error_msg_and_die("can't open %s, %s.zip, %s.ZIP", src_fn, src_fn, src_fn);
		}
	}

	/* Change dir if necessary */
	if (base_dir)
		xchdir(base_dir);

	if (verbose) {
		printf("Archive:  %s\n", src_fn);
		if (listing){
			puts("  Length     Date   Time    Name\n"
			     " --------    ----   ----    ----");
		}
	}

	total_size = 0;
	total_entries = 0;
	while (1) {
		uint32_t magic;

		/* Check magic number */
		xread(src_fd, &magic, 4);
		/* Central directory? It's at the end, so exit */
		if (magic == ZIP_CDS_MAGIC)
			break;
		if (magic != ZIP_FILEHEADER_MAGIC)
			bb_error_msg_and_die("invalid zip magic %08X", (int)magic);

		/* Read the file header */
		xread(src_fd, zip_header.raw, ZIP_HEADER_LEN);
		FIX_ENDIANNESS(zip_header);
		if ((zip_header.formatted.method != 0) && (zip_header.formatted.method != 8)) {
			bb_error_msg_and_die("unsupported method %d", zip_header.formatted.method);
		}
		if (zip_header.formatted.flags & (0x0008|0x0001)) {
			/* 0x0001 - encrypted */
			/* 0x0008 - streaming. [u]cmpsize can be reliably gotten
			 * only from Central Directory. See unzip_doc.txt */
			bb_error_msg_and_die("zip flags 8 and 1 are not supported");
		}

		/* Read filename */
		free(dst_fn);
		dst_fn = xzalloc(zip_header.formatted.filename_len + 1);
		xread(src_fd, dst_fn, zip_header.formatted.filename_len);

		/* Skip extra header bytes */
		unzip_skip(src_fd, zip_header.formatted.extra_len);

		/* Filter zip entries */
		if (find_list_entry(zreject, dst_fn)
		 || (zaccept && !find_list_entry(zaccept, dst_fn))
		) { /* Skip entry */
			i = 'n';

		} else { /* Extract entry */
			if (listing) { /* List entry */
				if (verbose) {
					unsigned dostime = zip_header.formatted.modtime | (zip_header.formatted.moddate << 16);
					printf("%9u  %02u-%02u-%02u %02u:%02u   %s\n",
					   zip_header.formatted.ucmpsize,
					   (dostime & 0x01e00000) >> 21,
					   (dostime & 0x001f0000) >> 16,
					   (((dostime & 0xfe000000) >> 25) + 1980) % 100,
					   (dostime & 0x0000f800) >> 11,
					   (dostime & 0x000007e0) >> 5,
					   dst_fn);
					total_size += zip_header.formatted.ucmpsize;
					total_entries++;
				} else {
					/* short listing -- filenames only */
					puts(dst_fn);
				}
				i = 'n';
			} else if (dst_fd == STDOUT_FILENO) { /* Extracting to STDOUT */
				i = -1;
			} else if (last_char_is(dst_fn, '/')) { /* Extract directory */
				if (stat(dst_fn, &stat_buf) == -1) {
					if (errno != ENOENT) {
						bb_perror_msg_and_die("cannot stat '%s'", dst_fn);
					}
					if (verbose) {
						printf("   creating: %s\n", dst_fn);
					}
					unzip_create_leading_dirs(dst_fn);
					if (bb_make_directory(dst_fn, 0777, 0)) {
						bb_error_msg_and_die("exiting");
					}
				} else {
					if (!S_ISDIR(stat_buf.st_mode)) {
						bb_error_msg_and_die("'%s' exists but is not directory", dst_fn);
					}
				}
				i = 'n';

			} else {  /* Extract file */
 check_file:
				if (stat(dst_fn, &stat_buf) == -1) { /* File does not exist */
					if (errno != ENOENT) {
						bb_perror_msg_and_die("cannot stat '%s'", dst_fn);
					}
					i = 'y';
				} else { /* File already exists */
					if (overwrite == O_NEVER) {
						i = 'n';
					} else if (S_ISREG(stat_buf.st_mode)) { /* File is regular file */
						if (overwrite == O_ALWAYS) {
							i = 'y';
						} else {
							printf("replace %s? [y]es, [n]o, [A]ll, [N]one, [r]ename: ", dst_fn);
							if (!fgets(key_buf, sizeof(key_buf), stdin)) {
								bb_perror_msg_and_die("cannot read input");
							}
							i = key_buf[0];
						}
					} else { /* File is not regular file */
						bb_error_msg_and_die("'%s' exists but is not regular file", dst_fn);
					}
				}
			}
		}

		switch (i) {
		case 'A':
			overwrite = O_ALWAYS;
		case 'y': /* Open file and fall into unzip */
			unzip_create_leading_dirs(dst_fn);
			dst_fd = xopen(dst_fn, O_WRONLY | O_CREAT | O_TRUNC);
		case -1: /* Unzip */
			if (verbose) {
				printf("  inflating: %s\n", dst_fn);
			}
			unzip_extract(&zip_header, src_fd, dst_fd);
			if (dst_fd != STDOUT_FILENO) {
				/* closing STDOUT is potentially bad for future business */
				close(dst_fd);
			}
			break;

		case 'N':
			overwrite = O_NEVER;
		case 'n':
			/* Skip entry data */
			unzip_skip(src_fd, zip_header.formatted.cmpsize);
			break;

		case 'r':
			/* Prompt for new name */
			printf("new name: ");
			if (!fgets(key_buf, sizeof(key_buf), stdin)) {
				bb_perror_msg_and_die("cannot read input");
			}
			free(dst_fn);
			dst_fn = xstrdup(key_buf);
			chomp(dst_fn);
			goto check_file;

		default:
			printf("error: invalid response [%c]\n",(char)i);
			goto check_file;
		}

// Looks like bug (data descriptor cannot be identified this way)
//		/* Data descriptor section */
//		if (zip_header.formatted.flags & 4) {
//			/* skip over duplicate crc, compressed size and uncompressed size */
//			unzip_skip(src_fd, 12);
//		}
	}

	if (listing && verbose) {
		printf(" --------                   -------\n"
		       "%9d                   %d files\n",
		       total_size, total_entries);
	}

	return 0;
}