/* gzio.c - decompression support for gzip */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2005,2006,2007,2009 Free Software Foundation, Inc.
*
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Most of this file was originally the source file "inflate.c", written
* by Mark Adler. It has been very heavily modified. In particular, the
* original would run through the whole file at once, and this version can
* be stopped and restarted on any boundary during the decompression process.
*
* The license and header comments that file are included here.
*/
/* inflate.c -- Not copyrighted 1992 by Mark Adler
version c10p1, 10 January 1993 */
/* You can do whatever you like with this source file, though I would
prefer that if you modify it and redistribute it that you include
comments to that effect with your name and the date. Thank you.
*/
GRUB_MOD_LICENSE ("GPLv3+");
/*
* Window Size
*
* This must be a power of two, and at least 32K for zip's deflate method
*/
/* The state stored in filesystem-specific data. */
struct grub_gzio
{
/* The underlying file object. */
/* If input is in memory following fields are used instead of file. */
/* The offset at which the data starts in the underlying file. */
/* The type of current block. */
int block_type;
/* The length of current block. */
int block_len;
/* The flag of the last block. */
int last_block;
/* The flag of codes. */
int code_state;
/* The length of a copy. */
unsigned inflate_n;
/* The index of a copy. */
unsigned inflate_d;
/* The input buffer. */
int inbuf_d;
/* The bit buffer. */
unsigned long bb;
/* The bits in the bit buffer. */
unsigned bk;
/* The sliding window in uncompressed data. */
/* Current position in the slide. */
unsigned wp;
/* The distance code table. */
int bl;
/* The lookup bits for the distance code table. */
int bd;
/* The original offset value. */
};
/* Declare the filesystem structure for grub_gzio_open. */
/* Function prototypes */
static void initialize_tables (grub_gzio_t);
/* Eat variable-length header fields. */
static int
{
do
{
if (len >= 0)
{
if (! (len--))
break;
}
else
{
if (! ch)
break;
}
}
return ! not_retval;
}
/* Little-Endian defines for the 2-byte magic numbers for gzip files. */
/* Compression methods (see algorithm.doc) */
#define STORED 0
/* methods 4 to 7 reserved */
/* gzip flag byte */
/* inflate block codes */
#define INFLATE_STORED 0
typedef unsigned char uch;
typedef unsigned short ush;
typedef unsigned long ulg;
static int
{
struct {
} hdr;
/*
* 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.
*/
{
return 0;
}
/*
* 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.
*/
{
return 0;
}
/* FIXME: don't do this on not easily seekable files. */
{
{
return 0;
}
/* FIXME: this does not handle files whose original size is over 4GB.
But how can we know the real original size? */
} else {
/* File size is AT LEAST this amount */
}
return 1;
}
/* Huffman code lookup table entry--this entry is four bytes for machines
that have 16-bit pointers (e.g. PC's in the small or medium model).
Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16
means that v is a literal, 16 < e < 32 means that v is a pointer to
the next table, which codes e - 16 bits, and lastly e == 99 indicates
an unused code. If a code with e == 99 is looked up, this implies an
error in the data. */
struct huft
{
uch e; /* number of extra bits or operation */
uch b; /* number of bits in this code or subcode */
union
{
ush n; /* literal, length base, or distance base */
struct huft *t; /* pointer to next level of table */
}
v;
};
/* The inflate algorithm uses a sliding 32K byte window on the uncompressed
stream to find repeated byte strings. This is implemented here as a
circular buffer. The index is updated simply by incrementing and then
and'ing with 0x7fff (32K-1). */
/* It is left to other modules to supply the 32K area. It is assumed
to be usable as if it were declared "uch slide[32768];" or as just
"uch *slide;" and then malloc'ed in the latter case. The definition
must be in unzip.h, included above. */
/* Tables for deflate from PKZIP's appnote.txt. */
static unsigned bitorder[] =
{ /* Order of the bit length code lengths */
16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
{ /* Copy lengths for literal codes 257..285 */
3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
/* note: see note #13 above about the 258 in this list. */
{ /* Extra bits for literal codes 257..285 */
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */
{ /* Copy offsets for distance codes 0..29 */
1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
8193, 12289, 16385, 24577};
{ /* Extra bits for distance codes */
0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
12, 12, 13, 13};
/*
Huffman code decoding is performed using a multi-level table lookup.
The fastest way to decode is to simply build a lookup table whose
size is determined by the longest code. However, the time it takes
to build this table can also be a factor if the data being decoded
is not very long. The most common codes are necessarily the
shortest codes, so those codes dominate the decoding time, and hence
the speed. The idea is you can have a shorter table that decodes the
shorter, more probable codes, and then point to subsidiary tables for
the longer codes. The time it costs to decode the longer codes is
then traded against the time it takes to make longer tables.
This results of this trade are in the variables lbits and dbits
below. lbits is the number of bits the first level table for literal/
length codes can decode in one step, and dbits is the same thing for
the distance codes. Subsequent tables are also less than or equal to
those sizes. These values may be adjusted either when all of the
codes are shorter than that, in which case the longest code length in
bits is used, or when the shortest code is *longer* than the requested
table size, in which case the length of the shortest code in bits is
used.
There are two different values for the two tables, since they code a
codes 286 possible values, or in a flat code, a little over eight
bits. The distance table codes 30 possible values, or a little less
than five bits, flat. The optimum values for speed end up being
about one bit more than those, so lbits is 8+1 and dbits is 5+1.
The optimum values may differ though from machine to machine, and
possibly even between compilers. Your mileage may vary.
*/
/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
/* Macros for inflate() bit peeking and grabbing.
The usage is:
NEEDBITS(j)
x = b & mask_bits[j];
DUMPBITS(j)
where NEEDBITS makes sure that b has at least j bits in it, and
DUMPBITS removes the bits from b. The macros use the variable k
for the number of bits in b. Normally, b and k are register
variables for speed, and are initialized at the beginning of a
routine that uses these macros from a global bit buffer and count.
If we assume that EOB will be the longest code, then we will never
ask for bits with NEEDBITS that are beyond the end of the stream.
So, NEEDBITS should not read any more bytes than are needed to
meet the request. Then no bytes need to be "returned" to the buffer
at the end of the last block.
However, this assumption is not true for fixed blocks--the EOB code
(The EOB code is shorter than other codes because fixed blocks are
generally short. So, while a block always has an EOB, many other
showing up at all.) However, by making the first table have a
lookup of seven bits, the EOB code will be found in that first
lookup, and so will not require that too many bits be pulled from
the stream.
*/
{
0x0000,
0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
};
#define DUMPBITS(n) do {b>>=(n);k-=(n);} while (0)
static int
{
{
return 0;
}
{
}
}
static void
{
{
"attempt to seek outside of the file");
else
}
else
}
/* more function prototypes */
struct huft **, int *);
static int inflate_codes_in_window (grub_gzio_t);
/* Given a list of code lengths and a maximum table size, make a set of
tables to decode that set of codes. Return zero on success, one if
the given code set is incomplete (the tables are still built in this
case), two if the input is invalid (all zero length codes or an
oversubscribed set of lengths), and three if not enough memory. */
static int
unsigned n, /* number of codes (assumed <= N_MAX) */
unsigned s, /* number of simple-valued codes (0..s-1) */
ush * d, /* list of base values for non-simple codes */
ush * e, /* list of extra bits for non-simple codes */
struct huft **t, /* result: starting table */
int *m) /* maximum lookup bits, returns actual */
{
unsigned a; /* counter for codes of length k */
unsigned f; /* i repeats in table every f entries */
int g; /* maximum code length */
int h; /* table level */
register unsigned i; /* counter, current code */
register unsigned j; /* counter */
register int k; /* number of bits in current code */
int l; /* bits per table (returned in m) */
register unsigned *p; /* pointer into c[], b[], or v[] */
register struct huft *q; /* points to current table */
struct huft r; /* table entry for structure assignment */
unsigned v[N_MAX]; /* values in order of bit length */
register int w; /* bits before this table == (l * h) */
int y; /* number of dummy codes added */
unsigned z; /* number of entries in current table */
/* Generate counts for each bit length */
grub_memset ((char *) c, 0, sizeof (c));
p = b;
i = n;
do
{
c[*p]++; /* assume all entries <= BMAX */
p++; /* Can't combine with above line (Solaris bug) */
}
while (--i);
if (c[0] == n) /* null input--all zero length codes */
{
*m = 0;
return 0;
}
/* Find minimum and maximum length, bound *m by those */
l = *m;
for (j = 1; j <= BMAX; j++)
if (c[j])
break;
k = j; /* minimum code length */
if ((unsigned) l < j)
l = j;
for (i = BMAX; i; i--)
if (c[i])
break;
g = i; /* maximum code length */
if ((unsigned) l > i)
l = i;
*m = l;
/* Adjust last length count to fill out codes, if needed */
for (y = 1 << j; j < i; j++, y <<= 1)
if ((y -= c[j]) < 0)
return 2; /* bad input: more codes than bits */
if ((y -= c[i]) < 0)
return 2;
c[i] += y;
/* Generate starting offsets into the value table for each length */
x[1] = j = 0;
p = c + 1;
xp = x + 2;
while (--i)
{ /* note that i == g from above */
*xp++ = (j += *p++);
}
/* Make a table of values in order of bit lengths */
p = b;
i = 0;
do
{
if ((j = *p++) != 0)
v[x[j]++] = i;
}
while (++i < n);
/* Generate the Huffman codes and for each, make the table entries */
x[0] = i = 0; /* first Huffman code is zero */
p = v; /* grab values in bit order */
h = -1; /* no tables yet--level -1 */
w = -l; /* bits decoded == (l * h) */
z = 0; /* ditto */
/* go through the bit lengths (k already is bits in shortest code) */
for (; k <= g; k++)
{
a = c[k];
while (a--)
{
/* here i is the Huffman code of length k bits for value *p */
/* make tables up to required level */
while (k > w + l)
{
h++;
w += l; /* previous table always l bits */
/* compute minimum size table less than or equal to l bits */
z = (z = (unsigned) (g - w)) > (unsigned) l ? (unsigned) l : z; /* upper limit on table size */
if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */
{ /* too few codes for k-w bit table */
f -= a + 1; /* deduct codes from patterns left */
xp = c + k;
while (++j < z) /* try smaller tables up to z bits */
{
if ((f <<= 1) <= *++xp)
break; /* enough codes to use up j bits */
f -= *xp; /* else deduct codes from patterns */
}
}
z = 1 << j; /* table entries for j-bit table */
/* allocate and link in new table */
if (! q)
{
if (h)
huft_free (u[0]);
return 3;
}
*t = q + 1; /* link to list for huft_free() */
u[h] = ++q; /* table starts after link */
/* connect to last table, if there is one */
if (h)
{
x[h] = i; /* save pattern for backing up */
r.b = (uch) l; /* bits to dump before this table */
r.v.t = q; /* pointer to this table */
j = i >> (w - l); /* (get around Turbo C bug) */
u[h - 1][j] = r; /* connect to last table */
}
}
/* set up table entry in r */
r.b = (uch) (k - w);
if (p >= v + n)
r.e = 99; /* out of values--invalid code */
else if (*p < s)
{
r.v.n = (ush) (*p); /* simple code is just the value */
p++; /* one compiler does not like *p++ */
}
else
{
r.e = (uch) e[*p - s]; /* non-simple--look up in lists */
r.v.n = d[*p++ - s];
}
/* fill code-like entries with r */
f = 1 << (k - w);
for (j = i >> w; j < z; j += f)
q[j] = r;
/* backwards increment the k-bit code i */
for (j = 1 << (k - 1); i & j; j >>= 1)
i ^= j;
i ^= j;
/* backup over finished tables */
while ((i & ((1 << w) - 1)) != x[h])
{
h--; /* don't need to update q */
w -= l;
}
}
}
/* Return true (1) if we were given an incomplete table */
return y != 0 && g != 1;
}
/* Free the malloc'ed tables built by huft_build(), which makes a linked
list of the tables it made, with the links in a dummy first entry of
each table. */
static int
{
register struct huft *p, *q;
/* Go through linked list, freeing from the malloced (t[-1]) address. */
p = t;
{
q = (--p)->v.t;
grub_free ((char *) p);
p = q;
}
return 0;
}
/*
* inflate (decompress) the codes in a deflated (compressed) block.
* Return an error code or zero if it all goes ok.
*/
static int
{
unsigned n, d; /* length and index for copy */
unsigned w; /* current window position */
struct huft *t; /* pointer to table entry */
register ulg b; /* bit buffer */
register unsigned k; /* number of bits in bit buffer */
/* make local copies of globals */
/* inflate the coded data */
for (;;) /* do until end of block */
{
if (! gzio->code_state)
{
do
{
if (e == 99)
{
"an unused code found");
return 1;
}
DUMPBITS (t->b);
e -= 16;
NEEDBITS (e);
}
while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
DUMPBITS (t->b);
if (e == 16) /* then it's a literal */
{
if (w == WSIZE)
break;
}
else
/* it's an EOB or a length */
{
/* exit if end of block */
if (e == 15)
{
break;
}
/* get length of block to copy */
NEEDBITS (e);
n = t->v.n + ((unsigned) b & mask_bits[e]);
DUMPBITS (e);
/* decode distance of block to copy */
do
{
if (e == 99)
{
"an unused code found");
return 1;
}
DUMPBITS (t->b);
e -= 16;
NEEDBITS (e);
}
while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e)
> 16);
DUMPBITS (t->b);
NEEDBITS (e);
d = w - t->v.n - ((unsigned) b & mask_bits[e]);
DUMPBITS (e);
gzio->code_state++;
}
}
if (gzio->code_state)
{
/* do the copy */
do
{
: e);
if (w - d >= e)
{
w += e;
d += e;
}
else
/* purposefully use the overlap for extra copies here!! */
{
while (e--)
}
if (w == WSIZE)
break;
}
while (n);
if (! n)
gzio->code_state--;
/* did we break from the loop too soon? */
if (w == WSIZE)
break;
}
}
/* restore the globals from the locals */
}
/* get header for an inflated type 0 (stored) block. */
static void
{
register ulg b; /* bit buffer */
register unsigned k; /* number of bits in bit buffer */
/* make local copies of globals */
/* go to byte boundary */
DUMPBITS (k & 7);
/* get the length and its complement */
NEEDBITS (16);
DUMPBITS (16);
NEEDBITS (16);
"the length of a stored block does not match");
DUMPBITS (16);
/* restore global variables */
}
/* get header for an inflated type 1 (fixed Huffman codes) block. We should
either replace this with a custom decoder, or at least precompute the
Huffman tables. */
static void
{
int i; /* temporary variable */
unsigned l[288]; /* length list for huft_build */
/* set up literal table */
for (i = 0; i < 144; i++)
l[i] = 8;
for (; i < 256; i++)
l[i] = 9;
for (; i < 280; i++)
l[i] = 7;
for (; i < 288; i++) /* make a complete, but wrong code set */
l[i] = 8;
{
if (grub_errno == GRUB_ERR_NONE)
"failed in building a Huffman code table");
return;
}
/* set up distance table */
for (i = 0; i < 30; i++) /* make an incomplete code set */
l[i] = 5;
{
if (grub_errno == GRUB_ERR_NONE)
"failed in building a Huffman code table");
return;
}
/* indicate we're now working on a block */
gzio->code_state = 0;
}
/* get header for an inflated type 2 (dynamic Huffman codes) block. */
static void
{
int i; /* temporary variables */
unsigned j;
unsigned l; /* last length */
unsigned m; /* mask for bit lengths table */
unsigned n; /* number of lengths to get */
register ulg b; /* bit buffer */
register unsigned k; /* number of bits in bit buffer */
/* make local bit buffer */
/* read in table lengths */
NEEDBITS (5);
DUMPBITS (5);
NEEDBITS (5);
DUMPBITS (5);
NEEDBITS (4);
DUMPBITS (4);
{
return;
}
/* read in bit-length-code lengths */
for (j = 0; j < nb; j++)
{
NEEDBITS (3);
DUMPBITS (3);
}
for (; j < 19; j++)
/* build decoding table for trees--single level, 7 bit lookup */
{
"failed in building a Huffman code table");
return;
}
/* read in literal and distance code lengths */
i = l = 0;
while ((unsigned) i < n)
{
DUMPBITS (j);
if (j < 16) /* length of code in bits (0..15) */
ll[i++] = l = j; /* save last length in l */
else if (j == 16) /* repeat last length 3 to 6 times */
{
NEEDBITS (2);
j = 3 + ((unsigned) b & 3);
DUMPBITS (2);
if ((unsigned) i + j > n)
{
return;
}
while (j--)
ll[i++] = l;
}
else if (j == 17) /* 3 to 10 zero length codes */
{
NEEDBITS (3);
j = 3 + ((unsigned) b & 7);
DUMPBITS (3);
if ((unsigned) i + j > n)
{
return;
}
while (j--)
ll[i++] = 0;
l = 0;
}
else
/* j == 18: 11 to 138 zero length codes */
{
NEEDBITS (7);
j = 11 + ((unsigned) b & 0x7f);
DUMPBITS (7);
if ((unsigned) i + j > n)
{
return;
}
while (j--)
ll[i++] = 0;
l = 0;
}
}
/* free decoding table for trees */
/* restore the global bit buffer */
{
"failed in building a Huffman code table");
return;
}
{
"failed in building a Huffman code table");
return;
}
/* indicate we're now working on a block */
gzio->code_state = 0;
}
static void
{
register ulg b; /* bit buffer */
register unsigned k; /* number of bits in bit buffer */
/* make local bit buffer */
/* read in last block bit */
NEEDBITS (1);
DUMPBITS (1);
/* read in block type */
NEEDBITS (2);
DUMPBITS (2);
/* restore the global bit buffer */
switch (gzio->block_type)
{
case INFLATE_STORED:
break;
case INFLATE_FIXED:
break;
case INFLATE_DYNAMIC:
break;
default:
break;
}
}
static void
{
/* initialize window */
/*
* Main decompression loop.
*/
{
{
if (gzio->last_block)
break;
}
if (grub_errno != GRUB_ERR_NONE)
return;
/*
* Expand stored block here.
*/
{
/*
* This is basically a glorified pass-through
*/
{
}
continue;
}
/*
* Expand other kind of block.
*/
if (inflate_codes_in_window (gzio))
{
}
}
/* XXX do CRC calculation here! */
}
static void
{
gzio->saved_offset = 0;
/* Initialize the bit buffer. */
/* Reset partial decompression code. */
gzio->last_block = 0;
/* Reset memory allocation stuff. */
}
/* Open a new decompressing object on the top of IO. If TRANSPARENT is true,
even if IO does not contain data compressed by gzip, return a valid file
object. Note that this function won't close IO, even if an error occurs. */
static grub_file_t
{
if (! file)
return 0;
if (! gzio)
{
return 0;
}
if (! test_gzip_header (file))
{
grub_file_seek (io, 0);
return io;
}
return file;
}
static int
{
/* Check that compression method is DEFLATE. */
{
return 0;
}
{
return 0;
}
/* Dictionary isn't supported. */
if (flg & 0x20)
{
return 0;
}
return 1;
}
static grub_ssize_t
{
/* Do we reset decompression to the beginning of the file? */
/*
* This loop operates upon uncompressed data only. The only
* special thing it does is to make sure the decompression
* window is within the range of data it needs.
*/
{
register char *srcaddr;
}
if (grub_errno != GRUB_ERR_NONE)
ret = -1;
return ret;
}
static grub_ssize_t
{
}
/* Release everything, including the underlying file object. */
static grub_err_t
{
/* No need to close the same device twice. */
return grub_errno;
}
{
if (! gzio)
return -1;
gzio->mem_input_off = 0;
if (!test_zlib_header (gzio))
{
return -1;
}
/* FIXME: Check Adler. */
return ret;
}
{
.name = "gzio",
.dir = 0,
.open = 0,
.read = grub_gzio_read,
.close = grub_gzio_close,
.label = 0,
.next = 0
};
{
}
{
}