static int
get_byte (void)
{
if (filepos == gzip_data_offset || bufloc == INBUFSIZ)
{
int pos;
int old_filepos = filepos;
bufloc = 0;
grub_read (inbuf, INBUFSIZ);
/* If there are 8 bytes or less left, we have read in all the
* the file content. So get the last 8 bytes and get the crc
* and uncompressed size. This is important for the loop in
* gunzip_read() to terminate properly.
*/
if (filepos >= filemax - 8) {
uch *eb = endbuf;
for (pos = filemax - 8; pos < filepos; pos++)
*eb++ = inbuf[pos - old_filepos];
if (filemax > filepos)
grub_read(eb, filemax - filepos);
gzip_crc = *((unsigned long *) endbuf);
gzip_filemax = *((unsigned long *) (endbuf + 4));
}
}
return inbuf[bufloc++];
}
static int
load_file(char *name, void **ptr, long *size)
{
char *buf = NULL;
int allocated = 1 * 1024 * 1024;
int len, filled = 0;
if (!grub_open (name))
return -1;
buf = malloc(allocated);
errnum = 0;
while (1) {
len = grub_read (buf + filled, allocated - filled);
if (! len) {
if (!errnum)
break;
grub_close ();
return -1;
}
filled += len;
if (filled < allocated)
break;
allocated *= 2;
buf = realloc(buf, allocated);
}
grub_close ();
*ptr = buf;
*size = filled;
return 0;
}
static int
get_byte (void)
{
if (filepos == gzip_data_offset || bufloc == INBUFSIZ)
{
bufloc = 0;
grub_read (inbuf, INBUFSIZ);
}
return inbuf[bufloc++];
}
void
cmain (void)
{
grub_printf ("\n\nGRUB loading, please wait...\n");
/*
* Here load the true second-stage boot-loader.
*/
if (grub_open (config_file))
{
int ret;
disk_read_hook = disk_read_savesect_func;
grub_read ((char *) 0x8000, SECTOR_SIZE * 2);
disk_read_hook = NULL;
/* Sanity check: catch an internal error. */
if (saved_sector == -1)
{
grub_printf ("internal error: the second sector of Stage 2 is unknown.");
stop ();
}
ret = grub_read ((char *) 0x8000 + SECTOR_SIZE * 2, -1);
grub_close ();
if (ret)
chain_stage2 (0, 0x8200, saved_sector);
}
/*
* If not, then print error message and die.
*/
print_error ();
stop ();
}
/* internal function for eating variable-length header fields */
static int
bad_field (int len)
{
char ch = 1;
int not_retval = 1;
do
{
if (len >= 0)
{
if (!(len--))
break;
}
else
{
if (!ch)
break;
}
}
while ((not_retval = grub_read (&ch, 1)) == 1);
return (!not_retval);
}
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;
}