aboutsummaryrefslogtreecommitdiff
path: root/archival/libunarchive/get_header_cpio.c
blob: 4ed18c68f3eac7009e16fa192afd9518530d062a (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
/* vi: set sw=4 ts=4: */
/* Copyright 2002 Laurence Anderson
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

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

typedef struct hardlinks_s {
	struct hardlinks_s *next;
	int inode; /* TODO: must match maj/min too! */
	int mode ;
	int mtime; /* These three are useful only in corner case */
	int uid  ; /* of hardlinks with zero size body */
	int gid  ;
	char name[1];
} hardlinks_t;

char FAST_FUNC get_header_cpio(archive_handle_t *archive_handle)
{
	static hardlinks_t *saved_hardlinks = NULL;
	static hardlinks_t *saved_hardlinks_created = NULL;

	file_header_t *file_header = archive_handle->file_header;
	char cpio_header[110];
	char dummy[16];
	int namesize;
	int major, minor, nlink, mode, inode;
	unsigned size, uid, gid, mtime;

	/* There can be padding before archive header */
	data_align(archive_handle, 4);

	if (archive_xread_all_eof(archive_handle, (unsigned char*)cpio_header, 110) == 0) {
		goto create_hardlinks;
	}
	archive_handle->offset += 110;

	if (strncmp(&cpio_header[0], "07070", 5) != 0
	 || (cpio_header[5] != '1' && cpio_header[5] != '2')
	) {
		bb_error_msg_and_die("unsupported cpio format, use newc or crc");
	}

	sscanf(cpio_header + 6,
			"%8x" "%8x" "%8x" "%8x"
			"%8x" "%8x" "%8x" /*maj,min:*/ "%16c"
			/*rmaj,rmin:*/"%8x" "%8x" "%8x" /*chksum:*/ "%8c",
			&inode, &mode, &uid, &gid,
			&nlink, &mtime, &size, dummy,
			&major, &minor, &namesize, dummy);
	file_header->mode = mode;
	file_header->uid = uid;
	file_header->gid = gid;
	file_header->mtime = mtime;
	file_header->size = size;

	file_header->name = xzalloc(namesize + 1);
	/* Read in filename */
	xread(archive_handle->src_fd, file_header->name, namesize);
	archive_handle->offset += namesize;

	/* Update offset amount and skip padding before file contents */
	data_align(archive_handle, 4);

	if (strcmp(file_header->name, "TRAILER!!!") == 0) {
		/* Always round up. ">> 9" divides by 512 */
		printf("%"OFF_FMT"u blocks\n", (archive_handle->offset + 511) >> 9);
		goto create_hardlinks;
	}

	if (S_ISLNK(file_header->mode)) {
		file_header->link_target = xzalloc(file_header->size + 1);
		xread(archive_handle->src_fd, file_header->link_target, file_header->size);
		archive_handle->offset += file_header->size;
		file_header->size = 0; /* Stop possible seeks in future */
	} else {
		file_header->link_target = NULL;
	}

// TODO: data_extract_all can't deal with hardlinks to non-files...
// (should be !S_ISDIR instead of S_ISREG here)

	if (nlink > 1 && S_ISREG(file_header->mode)) {
		hardlinks_t *new = xmalloc(sizeof(*new) + namesize);
		new->inode = inode;
		new->mode  = mode ;
		new->mtime = mtime;
		new->uid   = uid  ;
		new->gid   = gid  ;
		strcpy(new->name, file_header->name);
		/* Put file on a linked list for later */
		if (size == 0) {
			new->next = saved_hardlinks;
			saved_hardlinks = new;
			return EXIT_SUCCESS; /* Skip this one */
			/* TODO: this breaks cpio -t (it does not show hardlinks) */
		}
		new->next = saved_hardlinks_created;
		saved_hardlinks_created = new;
	}
	file_header->device = makedev(major, minor);

	if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
		archive_handle->action_data(archive_handle);
		archive_handle->action_header(file_header);
	} else {
		data_skip(archive_handle);
	}

	archive_handle->offset += file_header->size;

	free(file_header->link_target);
	free(file_header->name);
	file_header->link_target = NULL;
	file_header->name = NULL;

	return EXIT_SUCCESS;

 create_hardlinks:
	free(file_header->link_target);
	free(file_header->name);

	while (saved_hardlinks) {
		hardlinks_t *cur;
		hardlinks_t *make_me = saved_hardlinks;
		saved_hardlinks = make_me->next;

		memset(file_header, 0, sizeof(*file_header));
		file_header->name = make_me->name;
		file_header->mode = make_me->mode;
		/*file_header->size = 0;*/

		/* Try to find a file we are hardlinked to */
		cur = saved_hardlinks_created;
		while (cur) {
			/* TODO: must match maj/min too! */
			if (cur->inode == make_me->inode) {
				file_header->link_target = cur->name;
				 /* link_target != NULL, size = 0: "I am a hardlink" */
				if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
					archive_handle->action_data(archive_handle);
				free(make_me);
				goto next_link;
			}
		}
		/* Oops... no file with such inode was created... do it now
		 * (happens when hardlinked files are empty (zero length)) */
		file_header->mtime = make_me->mtime;
		file_header->uid   = make_me->uid  ;
		file_header->gid   = make_me->gid  ;
		if (archive_handle->filter(archive_handle) == EXIT_SUCCESS)
			archive_handle->action_data(archive_handle);
		/* Move to the list of created hardlinked files */
		make_me->next = saved_hardlinks_created;
		saved_hardlinks_created = make_me;
 next_link: ;
	}

	while (saved_hardlinks_created) {
		hardlinks_t *p = saved_hardlinks_created;
		saved_hardlinks_created = p->next;
		free(p);
	}

	return EXIT_FAILURE; /* "No more files to process" */
}