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/* 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;
} formated;
} header;
bb_xread_all(src_fd, header.raw, 8);
/* Check the compression method */
if (header.formated.method != 8) {
bb_error_msg_and_die("Unknown compression method %d",
header.formated.method);
}
if (header.formated.flags & 0x04) {
/* bit 2 set: extra field present */
unsigned char extra_short;
extra_short = bb_xread_char(src_fd) + (bb_xread_char(src_fd) << 8);
while (extra_short > 0) {
/* Ignore extra field */
bb_xread_char(src_fd);
extra_short--;
}
}
/* Discard original name if any */
if (header.formated.flags & 0x08) {
/* bit 3 set: original file name present */
while(bb_xread_char(src_fd) != 0);
}
/* Discard file comment if any */
if (header.formated.flags & 0x10) {
/* bit 4 set: file comment present */
while(bb_xread_char(src_fd) != 0);
}
/* Read the header checksum */
if (header.formated.flags & 0x02) {
bb_xread_char(src_fd);
bb_xread_char(src_fd);
}
return;
}
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