60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
|
|
*/
|
|
|
|
#include "libbb.h"
|
|
#include "unarchive.h" /* for external decl of check_header_gzip_or_die */
|
|
|
|
void check_header_gzip_or_die(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 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);
|
|
}
|
|
}
|