summaryrefslogtreecommitdiff
path: root/archival/libunarchive/get_header_cpio.c
blob: cd48601b683e1957e2fcd88b7cd377f0dfa9bb2f (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
/*
 *  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 <stdlib.h>
#include <string.h>
#include "unarchive.h"
#include "libbb.h"

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, (unsigned int*)&cpio_entry->mode, 
					(unsigned int*)&cpio_entry->uid, (unsigned int*)&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);
}