blob: 0cfa944540338c5a95720aef6de03075acc977c7 (
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
|
/* vi: set sw=4 ts=4: */
/*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include <stdlib.h>
#include <unistd.h>
#include "libbb.h"
#include "unarchive.h" /* for external decl of check_header_gzip */
void check_header_gzip(int src_fd)
{
union {
unsigned char raw[8];
struct {
unsigned char method;
unsigned char flags;
unsigned int mtime;
unsigned char xtra_flags;
unsigned char os_flags;
} formatted;
} header;
xread(src_fd, header.raw, 8);
/* Check the compression method */
if (header.formatted.method != 8) {
bb_error_msg_and_die("unknown compression method %d",
header.formatted.method);
}
if (header.formatted.flags & 0x04) {
/* bit 2 set: extra field present */
unsigned char extra_short;
extra_short = xread_char(src_fd) + (xread_char(src_fd) << 8);
while (extra_short > 0) {
/* Ignore extra field */
xread_char(src_fd);
extra_short--;
}
}
/* Discard original name if any */
if (header.formatted.flags & 0x08) {
/* bit 3 set: original file name present */
while (xread_char(src_fd) != 0);
}
/* Discard file comment if any */
if (header.formatted.flags & 0x10) {
/* bit 4 set: file comment present */
while (xread_char(src_fd) != 0);
}
/* Read the header checksum */
if (header.formatted.flags & 0x02) {
xread_char(src_fd);
xread_char(src_fd);
}
return;
}
|
