aboutsummaryrefslogtreecommitdiff
path: root/libbb/unarchive.c
blob: 78260d2d6f9d3658aeeb2d42816a0b3f0840397a (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
/*
 *  Copyright (C) 2000 by Glenn McGrath
 *  Copyright (C) 2001 by Laurence Anderson
 *	
 *  Based on previous work by busybox developers and others.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Library General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <utime.h>
#include "libbb.h"

extern void seek_sub_file(FILE *src_stream, const int count);
extern char *extract_archive(FILE *src_stream, FILE *out_stream, const file_header_t *file_entry,
 const int function, const char *prefix);


#ifdef L_archive_offset
off_t archive_offset;
#else
extern off_t archive_offset;
#endif	

#ifdef L_seek_sub_file
void seek_sub_file(FILE *src_stream, const int count)
{
	int i;
	/* Try to fseek as faster */
	archive_offset += count;
	if (fseek(src_stream, count, SEEK_CUR) != 0 && errno == ESPIPE) {
	for (i = 0; i < count; i++) {
		fgetc(src_stream);
		}
	}
	return;
}
#endif	



#ifdef L_extract_archive
/* Extract the data postioned at src_stream to either filesystem, stdout or 
 * buffer depending on the value of 'function' which is defined in libbb.h 
 *
 * prefix doesnt have to be just a directory, it may prefix the filename as well.
 *
 * e.g. '/var/lib/dpkg/info/dpkg.' will extract all files to the base bath 
 * '/var/lib/dpkg/info/' and all files/dirs created in that dir will have 
 * 'dpkg.' as their prefix
 *
 * For this reason if prefix does point to a dir then it must end with a
 * trailing '/' or else the last dir will be assumed to be the file prefix 
 */
char *extract_archive(FILE *src_stream, FILE *out_stream, const file_header_t *file_entry,
 const int function, const char *prefix)
{
	FILE *dst_stream = NULL;
	char *full_name = NULL;
	char *buffer = NULL;
	struct utimbuf t;

	/* prefix doesnt have to be a proper path it may prepend 
	 * the filename as well */
	if (prefix != NULL) {
		/* strip leading '/' in filename to extract as prefix may not be dir */
		/* Cant use concat_path_file here as prefix might not be a directory */
		char *path = file_entry->name;
		if (*path == '/') {
			path++;
		}
		full_name = xmalloc(strlen(prefix) + strlen(path) + 1);
		strcpy(full_name, prefix);
		strcat(full_name, path);
	} else {
		full_name = file_entry->name;
	}

	if (function & extract_to_stdout) {
		if (S_ISREG(file_entry->mode)) {
			copy_file_chunk(src_stream, out_stream, file_entry->size);			
			archive_offset += file_entry->size;
		}
	}
	else if (function & extract_one_to_buffer) { 
		if (S_ISREG(file_entry->mode)) {
			buffer = (char *) xmalloc(file_entry->size + 1);
			fread(buffer, 1, file_entry->size, src_stream);
			buffer[file_entry->size] = '\0';
			archive_offset += file_entry->size;
			return(buffer);
		}
	}
	else if (function & extract_all_to_fs) {
		struct stat oldfile;
		int stat_res;
		stat_res = lstat (full_name, &oldfile);
		if (stat_res == 0) { /* The file already exists */
			if ((function & extract_unconditional) || (oldfile.st_mtime < file_entry->mtime)) {
				if (!S_ISDIR(oldfile.st_mode)) {
					unlink(full_name); /* Directories might not be empty etc */
				}
			} else {
				if ((function & extract_quiet) != extract_quiet) {
					error_msg("%s not created: newer or same age file exists", file_entry->name);
				}
				seek_sub_file(src_stream, file_entry->size);
				return (NULL);
			}
		}
		if (function & extract_create_leading_dirs) { /* Create leading directories with default umask */
			char *parent = dirname(full_name);
			if (make_directory (parent, -1, FILEUTILS_RECUR) != 0) {
				if ((function & extract_quiet) != extract_quiet) {
					error_msg("couldn't create leading directories");
				}
			}
			free (parent);
		}
		switch(file_entry->mode & S_IFMT) {
			case S_IFREG:
				if (file_entry->link_name) { /* Found a cpio hard link */
					if (link(file_entry->link_name, full_name) != 0) {
						if ((function & extract_quiet) != extract_quiet) {
							perror_msg("Cannot link from %s to '%s'",
								file_entry->name, file_entry->link_name);
						}
					}
				} else {
					if ((dst_stream = wfopen(full_name, "w")) == NULL) {
						seek_sub_file(src_stream, file_entry->size);
						return NULL;
					}
					archive_offset += file_entry->size;
					copy_file_chunk(src_stream, dst_stream, file_entry->size);			
					fclose(dst_stream);
				}
				break;
			case S_IFDIR:
				if (stat_res != 0) {
					if (mkdir(full_name, file_entry->mode) < 0) {
						if ((function & extract_quiet) != extract_quiet) {
							perror_msg("extract_archive: ");
						}
					}
				}
				break;
			case S_IFLNK:
				if (symlink(file_entry->link_name, full_name) < 0) {
					if ((function & extract_quiet) != extract_quiet) {
						perror_msg("Cannot create symlink from %s to '%s'", file_entry->name, file_entry->link_name);
					}
					return NULL;
				}
				break;
			case S_IFSOCK:
			case S_IFBLK:
			case S_IFCHR:
			case S_IFIFO:
				if (mknod(full_name, file_entry->mode, file_entry->device) == -1) {
					if ((function & extract_quiet) != extract_quiet) {
						perror_msg("Cannot create node %s", file_entry->name);
					}
					return NULL;
				}
				break;
		}

		/* Changing a symlink's properties normally changes the properties of the 
		 * file pointed to, so dont try and change the date or mode, lchown does
		 * does the right thing, but isnt available in older versions of libc */
		if (S_ISLNK(file_entry->mode)) {
#if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
			lchown(full_name, file_entry->uid, file_entry->gid);
#endif
		} else {
			if (function & extract_preserve_date) {
				t.actime = file_entry->mtime;
				t.modtime = file_entry->mtime;
				utime(full_name, &t);
			}
			chmod(full_name, file_entry->mode);
			chown(full_name, file_entry->uid, file_entry->gid);
		}
	} else {
		/* If we arent extracting data we have to skip it, 
		 * if data size is 0 then then just do it anyway
		 * (saves testing for it) */
		seek_sub_file(src_stream, file_entry->size);
	}

	/* extract_list and extract_verbose_list can be used in conjunction
	 * with one of the above four extraction functions, so do this seperately */
	if (function & extract_verbose_list) {
		fprintf(out_stream, "%s %d/%d %8d %s ", mode_string(file_entry->mode), 
			file_entry->uid, file_entry->gid,
			(int) file_entry->size, time_string(file_entry->mtime));
	}
	if ((function & extract_list) || (function & extract_verbose_list)){
		/* fputs doesnt add a trailing \n, so use fprintf */
		fprintf(out_stream, "%s\n", file_entry->name);
	}

	free(full_name);

	return(NULL); /* Maybe we should say if failed */
}
#endif

#ifdef L_unarchive
char *unarchive(FILE *src_stream, FILE *out_stream, file_header_t *(*get_headers)(FILE *),
	const int extract_function, const char *prefix, char **extract_names)
{
	file_header_t *file_entry;
	int found;
	int i;
	char *buffer = NULL;

	archive_offset = 0;
	while ((file_entry = get_headers(src_stream)) != NULL) {
		found = FALSE;
		if (extract_names == NULL) {
			found = TRUE;
		} else {
			for(i = 0; extract_names[i] != 0; i++) {
				if (strcmp(extract_names[i], file_entry->name) == 0) {
					found = TRUE;
				}
			}
		}
		if (found) {
			buffer = extract_archive(src_stream, out_stream, file_entry, extract_function, prefix);
		} else {
			/* seek past the data entry */
			seek_sub_file(src_stream, file_entry->size);
		}
	}
	return(buffer);
}
#endif

#ifdef L_get_header_ar
file_header_t *get_header_ar(FILE *src_stream)
{
	file_header_t *typed;
	union {
		char raw[60];
	 	struct {
 			char name[16];
 			char date[12];
 			char uid[6];
 			char gid[6];
 			char mode[8];
 			char size[10];
 			char magic[2];
 		} formated;
	} ar;
	static char *ar_long_names;

	if (fread(ar.raw, 1, 60, src_stream) != 60) {
		return(NULL);
	}
	archive_offset += 60;
	/* align the headers based on the header magic */
	if ((ar.formated.magic[0] != '`') || (ar.formated.magic[1] != '\n')) {
		/* some version of ar, have an extra '\n' after each data entry,
		 * this puts the next header out by 1 */
		if (ar.formated.magic[1] != '`') {
			error_msg("Invalid magic");
			return(NULL);
		}
		/* read the next char out of what would be the data section,
		 * if its a '\n' then it is a valid header offset by 1*/
		archive_offset++;
		if (fgetc(src_stream) != '\n') {
			error_msg("Invalid magic");
			return(NULL);
		}
		/* fix up the header, we started reading 1 byte too early */
		/* raw_header[60] wont be '\n' as it should, but it doesnt matter */
		memmove(ar.raw, &ar.raw[1], 59);
	}
		
	typed = (file_header_t *) xcalloc(1, sizeof(file_header_t));

	typed->size = (size_t) atoi(ar.formated.size);
	/* long filenames have '/' as the first character */
	if (ar.formated.name[0] == '/') {
		if (ar.formated.name[1] == '/') {
			/* If the second char is a '/' then this entries data section
			 * stores long filename for multiple entries, they are stored
			 * in static variable long_names for use in future entries */
			ar_long_names = (char *) xrealloc(ar_long_names, typed->size);
			fread(ar_long_names, 1, typed->size, src_stream);
			archive_offset += typed->size;
			/* This ar entries data section only contained filenames for other records
			 * they are stored in the static ar_long_names for future reference */
			return (get_header_ar(src_stream)); /* Return next header */
		} else if (ar.formated.name[1] == ' ') {
			/* This is the index of symbols in the file for compilers */
			seek_sub_file(src_stream, typed->size);
			return (get_header_ar(src_stream)); /* Return next header */
		} else {
			/* The number after the '/' indicates the offset in the ar data section
			(saved in variable long_name) that conatains the real filename */
			if (!ar_long_names) {
				error_msg("Cannot resolve long file name");
				return (NULL);
			}
			typed->name = xstrdup(ar_long_names + atoi(&ar.formated.name[1]));
		}
	} else {
		/* short filenames */
		typed->name = xcalloc(1, 16);
		strncpy(typed->name, ar.formated.name, 16);
	}
	typed->name[strcspn(typed->name, " /")]='\0';

	/* convert the rest of the now valid char header to its typed struct */	
	parse_mode(ar.formated.mode, &typed->mode);
	typed->mtime = atoi(ar.formated.date);
	typed->uid = atoi(ar.formated.uid);
	typed->gid = atoi(ar.formated.gid);

	return(typed);
}
#endif

#ifdef L_get_header_cpio
struct hardlinks {
	file_header_t *entry;
	int inode;
	struct hardlinks *next;
};

file_header_t *get_header_cpio(FILE *src_stream)
{
	file_header_t *cpio_entry = NULL;
	char cpio_header[110];
	int namesize;
 	char dummy[16];
 	int major, minor, nlink, inode;
 	static struct hardlinks *saved_hardlinks = NULL;
 	static int pending_hardlinks = 0;

	if (pending_hardlinks) { /* Deal with any pending hardlinks */
		struct hardlinks *tmp = saved_hardlinks, *oldtmp = NULL;
		while (tmp) {
			if (tmp->entry->link_name) { /* Found a hardlink ready to be extracted */
				cpio_entry = tmp->entry;
				if (oldtmp) oldtmp->next = tmp->next; /* Remove item from linked list */
				else saved_hardlinks = tmp->next;
				free(tmp);
				return (cpio_entry);
			}
			oldtmp = tmp;
			tmp = tmp->next;
		}
		pending_hardlinks = 0; /* No more pending hardlinks, read next file entry */
	}
  
	/* There can be padding before archive header */
	seek_sub_file(src_stream, (4 - (archive_offset % 4)) % 4);
	if (fread(cpio_header, 1, 110, src_stream) == 110) {
		archive_offset += 110;
		if (strncmp(cpio_header, "07070", 5) != 0) {
			error_msg("Unsupported format or invalid magic");
			return(NULL);
		}
		switch (cpio_header[5]) {
			case '2': /* "crc" header format */
				/* Doesnt do the crc check yet */
			case '1': /* "newc" header format */
				cpio_entry = (file_header_t *) xcalloc(1, sizeof(file_header_t));
				sscanf(cpio_header, "%6c%8x%8x%8x%8x%8x%8lx%8lx%16c%8x%8x%8x%8c",
					dummy, &inode, &cpio_entry->mode, &cpio_entry->uid, &cpio_entry->gid,
					&nlink, &cpio_entry->mtime, &cpio_entry->size,
					dummy, &major, &minor, &namesize, dummy);

				cpio_entry->name = (char *) xcalloc(1, namesize);
				fread(cpio_entry->name, 1, namesize, src_stream); /* Read in filename */
				archive_offset += namesize;
				/* Skip padding before file contents */
				seek_sub_file(src_stream, (4 - (archive_offset % 4)) % 4);
				if (strcmp(cpio_entry->name, "TRAILER!!!") == 0) {
					printf("%d blocks\n", (int) (archive_offset % 512 ? (archive_offset / 512) + 1 : archive_offset / 512)); /* Always round up */
					if (saved_hardlinks) { /* Bummer - we still have unresolved hardlinks */
						struct hardlinks *tmp = saved_hardlinks, *oldtmp = NULL;
						while (tmp) {
							error_msg("%s not created: cannot resolve hardlink", tmp->entry->name);
							oldtmp = tmp;
							tmp = tmp->next;
							free (oldtmp->entry->name);
							free (oldtmp->entry);
							free (oldtmp);
						}
						saved_hardlinks = NULL;
						pending_hardlinks = 0;
					}
					return(NULL);
				}

				if (S_ISLNK(cpio_entry->mode)) {
					cpio_entry->link_name = (char *) xcalloc(1, cpio_entry->size + 1);
					fread(cpio_entry->link_name, 1, cpio_entry->size, src_stream);
					archive_offset += cpio_entry->size;
					cpio_entry->size = 0; /* Stop possiable seeks in future */
				}
				if (nlink > 1 && !S_ISDIR(cpio_entry->mode)) {
					if (cpio_entry->size == 0) { /* Put file on a linked list for later */
						struct hardlinks *new = xmalloc(sizeof(struct hardlinks));
						new->next = saved_hardlinks;
						new->inode = inode;
						new->entry = cpio_entry;
						saved_hardlinks = new;
					return(get_header_cpio(src_stream)); /* Recurse to next file */
					} else { /* Found the file with data in */
						struct hardlinks *tmp = saved_hardlinks;
						pending_hardlinks = 1;
						while (tmp) {
							if (tmp->inode == inode) {
								tmp->entry->link_name = xstrdup(cpio_entry->name);
								nlink--;
							}
							tmp = tmp->next;
						}
						if (nlink > 1) error_msg("error resolving hardlink: did you create the archive with GNU cpio 2.0-2.2?");
					}
				}
				cpio_entry->device = (major << 8) | minor;
				break;
			default:
				error_msg("Unsupported format");
				return(NULL);
		}
		if (ferror(src_stream) || feof(src_stream)) {
			perror_msg("Stream error");
			return(NULL);
		}
	}
	return(cpio_entry);
}
#endif

#ifdef L_get_header_tar
file_header_t *get_header_tar(FILE *tar_stream)
{
	union {
		unsigned char raw[512];
		struct {
			char name[100];		/*   0-99 */
			char mode[8];		/* 100-107 */
			char uid[8];		/* 108-115 */
			char gid[8];		/* 116-123 */
			char size[12];		/* 124-135 */
			char mtime[12];		/* 136-147 */
			char chksum[8];		/* 148-155 */
			char typeflag;		/* 156-156 */
			char linkname[100];	/* 157-256 */
			char magic[6];		/* 257-262 */
			char version[2];	/* 263-264 */
			char uname[32];		/* 265-296 */
			char gname[32];		/* 297-328 */
			char devmajor[8];	/* 329-336 */
			char devminor[8];	/* 337-344 */
			char prefix[155];	/* 345-499 */
			char padding[12];	/* 500-512 */
		} formated;
	} tar;
	file_header_t *tar_entry = NULL;
	long i;
	long sum = 0;

	if (archive_offset % 512 != 0) {
		seek_sub_file(tar_stream, 512 - (archive_offset % 512));
	}

	if (fread(tar.raw, 1, 512, tar_stream) != 512) {
		error_msg("Couldnt read header");
		return(NULL);
	}
	archive_offset += 512;

	/* Check header has valid magic, unfortunately some tar files
	 * have empty (0'ed) tar entries at the end, which will
	 * cause this to fail, so fail silently for now
	 */
	if (strncmp(tar.formated.magic, "ustar", 5) != 0) {
		return(NULL);
	}

	/* Do checksum on headers */
	for (i =  0; i < 148 ; i++) {
		sum += tar.raw[i];
	}
	sum += ' ' * 8;
	for (i =  156; i < 512 ; i++) {
		sum += tar.raw[i];
	}
	if (sum != strtol(tar.formated.chksum, NULL, 8)) {
		error_msg("Invalid tar header checksum");
		return(NULL);
	}

	/* convert to type'ed variables */
	tar_entry = xcalloc(1, sizeof(file_header_t));
	tar_entry->name = xstrdup(tar.formated.name);

	parse_mode(tar.formated.mode, &tar_entry->mode);
	tar_entry->uid   = strtol(tar.formated.uid, NULL, 8);
	tar_entry->gid   = strtol(tar.formated.gid, NULL, 8);
	tar_entry->size  = strtol(tar.formated.size, NULL, 8);
	tar_entry->mtime = strtol(tar.formated.mtime, NULL, 8);
	tar_entry->link_name  = strlen(tar.formated.linkname) ? 
	    xstrdup(tar.formated.linkname) : NULL;
	tar_entry->device = (strtol(tar.formated.devmajor, NULL, 8) << 8) +
		strtol(tar.formated.devminor, NULL, 8);

	return(tar_entry);
}
#endif

#ifdef L_deb_extract
char *deb_extract(const char *package_filename, FILE *out_stream, 
	const int extract_function, const char *prefix, const char *filename)
{
	FILE *deb_stream;
	FILE *uncompressed_stream = NULL;
	file_header_t *ar_header = NULL;
	char **file_list = NULL;
	char *output_buffer = NULL;
	char *ared_file = NULL;
	char ar_magic[8];
	int gunzip_pid;

	if (filename != NULL) {
		file_list = xmalloc(sizeof(char *) * 2);
		file_list[0] = xstrdup(filename);
		file_list[1] = NULL;
	}
	
	if (extract_function & extract_control_tar_gz) {
		ared_file = xstrdup("control.tar.gz");
	}
	else if (extract_function & extract_data_tar_gz) {		
		ared_file = xstrdup("data.tar.gz");
	}

	/* open the debian package to be worked on */
	deb_stream = wfopen(package_filename, "r");
	if (deb_stream == NULL) {
		return(NULL);
	}
	/* set the buffer size */
	setvbuf(deb_stream, NULL, _IOFBF, 0x8000);

	/* check ar magic */
	fread(ar_magic, 1, 8, deb_stream);
	if (strncmp(ar_magic,"!<arch>",7) != 0) {
		error_msg_and_die("invalid magic");
	}
	archive_offset = 8;

	while ((ar_header = get_header_ar(deb_stream)) != NULL) {
		if (strcmp(ared_file, ar_header->name) == 0) {
			/* open a stream of decompressed data */
			uncompressed_stream = gz_open(deb_stream, &gunzip_pid);
			archive_offset = 0;
			output_buffer = unarchive(uncompressed_stream, out_stream, get_header_tar, extract_function, prefix, file_list);
		}
		seek_sub_file(deb_stream, ar_header->size);
	}
	gz_close(gunzip_pid);
	fclose(deb_stream);
	fclose(uncompressed_stream);
	free(ared_file);
	return(output_buffer);
}
#endif