int
gunzip_test_header (void)
{
unsigned char buf[10];
/* "compressed_file" is already reset to zero by this point */
/*
* This checks if the file is gzipped. If a problem occurs here
* (other than a real error with the disk) then we don't think it
* is a compressed file, and simply mark it as such.
*/
if (no_decompression
|| grub_read (buf, 10) != 10
|| ((*((unsigned short *) buf) != GZIP_HDR_LE)
&& (*((unsigned short *) buf) != OLD_GZIP_HDR_LE)))
{
filepos = 0;
return ! errnum;
}
/*
* This does consistency checking on the header data. If a
* problem occurs from here on, then we have corrupt or otherwise
* bad data, and the error should be reported to the user.
*/
if (buf[2] != DEFLATED
|| (buf[3] & UNSUPP_FLAGS)
|| ((buf[3] & EXTRA_FIELD)
&& (grub_read (buf, 2) != 2
|| bad_field (*((unsigned short *) buf))))
|| ((buf[3] & ORIG_NAME) && bad_field (-1))
|| ((buf[3] & COMMENT) && bad_field (-1)))
{
if (! errnum)
errnum = ERR_BAD_GZIP_HEADER;
return 0;
}
gzip_data_offset = filepos;
filepos = filemax - 8;
if (grub_read (buf, 8) != 8)
{
if (! errnum)
errnum = ERR_BAD_GZIP_HEADER;
return 0;
}
gzip_crc = *((unsigned long *) buf);
gzip_fsmax = gzip_filemax = *((unsigned long *) (buf + 4));
initialize_tables ();
compressed_file = 1;
gunzip_swap_values ();
/*
* Now "gzip_*" values refer to the compressed data.
*/
filepos = 0;
return 1;
}
int
gunzip_test_header (void)
{
unsigned char buf[10];
/* "compressed_file" is already reset to zero by this point */
/*
* This checks if the file is gzipped. If a problem occurs here
* (other than a real error with the disk) then we don't think it
* is a compressed file, and simply mark it as such.
*/
if (no_decompression
|| grub_read (buf, 10) != 10
|| ((*((unsigned short *) buf) != GZIP_HDR_LE)
&& (*((unsigned short *) buf) != OLD_GZIP_HDR_LE)))
{
filepos = 0;
return ! errnum;
}
/*
* This does consistency checking on the header data. If a
* problem occurs from here on, then we have corrupt or otherwise
* bad data, and the error should be reported to the user.
*/
if (buf[2] != DEFLATED
|| (buf[3] & UNSUPP_FLAGS)
|| ((buf[3] & EXTRA_FIELD)
&& (grub_read (buf, 2) != 2
|| bad_field (*((unsigned short *) buf))))
|| ((buf[3] & ORIG_NAME) && bad_field (-1))
|| ((buf[3] & COMMENT) && bad_field (-1)))
{
if (! errnum)
errnum = ERR_BAD_GZIP_HEADER;
return 0;
}
gzip_data_offset = filepos;
/* We could read the last 8 bytes of the file to get the uncompressed
* size. Doing so under tftp would cause the file to be downloaded
* twice, which can be problem with large files. So we set it to
* MAXINT and correct it later when we get to the end of the file
* in get_byte().
*/
gzip_fsmax = gzip_filemax = MAXINT;
initialize_tables ();
compressed_file = 1;
gunzip_swap_values ();
/*
* Now "gzip_*" values refer to the compressed data.
*/
filepos = 0;
crc = (ulg)0xffffffffUL;
return 1;
}
