| /* gzio.c - decompression support for gzip */ |
| /* |
| * GRUB -- GRand Unified Bootloader |
| * Copyright (C) 1999,2005,2006,2007,2009 Free Software Foundation, Inc. |
| * |
| * GRUB is free software: you can redistribute it and/or modify |
| * 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. |
| */ |
| |
| #include <grub/err.h> |
| #include <grub/types.h> |
| #include <grub/mm.h> |
| #include <grub/misc.h> |
| #include <grub/fs.h> |
| #include <grub/file.h> |
| #include <grub/dl.h> |
| #include <grub/deflate.h> |
| #include <grub/i18n.h> |
| |
| GRUB_MOD_LICENSE ("GPLv3+"); |
| |
| /* |
| * Window Size |
| * |
| * This must be a power of two, and at least 32K for zip's deflate method |
| */ |
| |
| #define WSIZE 0x8000 |
| |
| |
| #define INBUFSIZ 0x2000 |
| |
| /* The state stored in filesystem-specific data. */ |
| struct grub_gzio |
| { |
| /* The underlying file object. */ |
| grub_file_t file; |
| /* If input is in memory following fields are used instead of file. */ |
| grub_size_t mem_input_size, mem_input_off; |
| grub_uint8_t *mem_input; |
| /* The offset at which the data starts in the underlying file. */ |
| grub_off_t data_offset; |
| /* 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. */ |
| grub_uint8_t inbuf[INBUFSIZ]; |
| int inbuf_d; |
| /* The bit buffer. */ |
| unsigned long bb; |
| /* The bits in the bit buffer. */ |
| unsigned bk; |
| /* The sliding window in uncompressed data. */ |
| grub_uint8_t slide[WSIZE]; |
| /* Current position in the slide. */ |
| unsigned wp; |
| /* The literal/length code table. */ |
| struct huft *tl; |
| /* The distance code table. */ |
| struct huft *td; |
| /* The lookup bits for the literal/length code table. */ |
| int bl; |
| /* The lookup bits for the distance code table. */ |
| int bd; |
| /* The original offset value. */ |
| grub_off_t saved_offset; |
| }; |
| typedef struct grub_gzio *grub_gzio_t; |
| |
| /* Declare the filesystem structure for grub_gzio_open. */ |
| static struct grub_fs grub_gzio_fs; |
| |
| /* Function prototypes */ |
| static void initialize_tables (grub_gzio_t); |
| |
| /* Eat variable-length header fields. */ |
| static int |
| eat_field (grub_file_t file, int len) |
| { |
| char ch = 1; |
| int not_retval = 1; |
| |
| do |
| { |
| if (len >= 0) |
| { |
| if (! (len--)) |
| break; |
| } |
| else |
| { |
| if (! ch) |
| break; |
| } |
| } |
| while ((not_retval = grub_file_read (file, &ch, 1)) == 1); |
| |
| return ! not_retval; |
| } |
| |
| |
| /* Little-Endian defines for the 2-byte magic numbers for gzip files. */ |
| #define GZIP_MAGIC grub_le_to_cpu16 (0x8B1F) |
| #define OLD_GZIP_MAGIC grub_le_to_cpu16 (0x9E1F) |
| |
| /* Compression methods (see algorithm.doc) */ |
| #define STORED 0 |
| #define COMPRESSED 1 |
| #define PACKED 2 |
| #define LZHED 3 |
| /* methods 4 to 7 reserved */ |
| #define DEFLATED 8 |
| #define MAX_METHODS 9 |
| |
| /* gzip flag byte */ |
| #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ |
| #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ |
| #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ |
| #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ |
| #define COMMENT 0x10 /* bit 4 set: file comment present */ |
| #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ |
| #define RESERVED 0xC0 /* bit 6,7: reserved */ |
| |
| #define UNSUPPORTED_FLAGS (CONTINUATION | ENCRYPTED | RESERVED) |
| |
| /* inflate block codes */ |
| #define INFLATE_STORED 0 |
| #define INFLATE_FIXED 1 |
| #define INFLATE_DYNAMIC 2 |
| |
| typedef unsigned char uch; |
| typedef unsigned short ush; |
| typedef unsigned long ulg; |
| |
| static int |
| test_gzip_header (grub_file_t file) |
| { |
| struct { |
| grub_uint16_t magic; |
| grub_uint8_t method; |
| grub_uint8_t flags; |
| grub_uint32_t timestamp; |
| grub_uint8_t extra_flags; |
| grub_uint8_t os_type; |
| } hdr; |
| grub_uint16_t extra_len; |
| grub_uint32_t orig_len; |
| grub_gzio_t gzio = file->data; |
| |
| if (grub_file_tell (gzio->file) != 0) |
| grub_file_seek (gzio->file, 0); |
| |
| /* |
| * 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 (grub_file_read (gzio->file, &hdr, 10) != 10 |
| || ((hdr.magic != GZIP_MAGIC) |
| && (hdr.magic != OLD_GZIP_MAGIC))) |
| 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. |
| */ |
| if (hdr.method != DEFLATED |
| || (hdr.flags & UNSUPPORTED_FLAGS) |
| || ((hdr.flags & EXTRA_FIELD) |
| && (grub_file_read (gzio->file, &extra_len, 2) != 2 |
| || eat_field (gzio->file, |
| grub_le_to_cpu16 (extra_len)))) |
| || ((hdr.flags & ORIG_NAME) && eat_field (gzio->file, -1)) |
| || ((hdr.flags & COMMENT) && eat_field (gzio->file, -1))) |
| return 0; |
| |
| gzio->data_offset = grub_file_tell (gzio->file); |
| |
| /* FIXME: don't do this on not easily seekable files. */ |
| { |
| grub_file_seek (gzio->file, grub_file_size (gzio->file) - 4); |
| if (grub_file_read (gzio->file, &orig_len, 4) != 4) |
| return 0; |
| /* FIXME: this does not handle files whose original size is over 4GB. |
| But how can we know the real original size? */ |
| file->size = grub_le_to_cpu32 (orig_len); |
| } |
| |
| initialize_tables (gzio); |
| |
| 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}; |
| static ush cplens[] = |
| { /* 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. */ |
| static ush cplext[] = |
| { /* 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 */ |
| static ush cpdist[] = |
| { /* 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}; |
| static ush cpdext[] = |
| { /* 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 |
| different number of possibilities each. The literal/length table |
| 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. |
| */ |
| |
| |
| static int lbits = 9; /* bits in base literal/length lookup table */ |
| static int dbits = 6; /* bits in base distance lookup table */ |
| |
| |
| /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */ |
| #define BMAX 16 /* maximum bit length of any code (16 for explode) */ |
| #define N_MAX 288 /* maximum number of codes in any set */ |
| |
| |
| /* 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 |
| is 7 bits, but the other literal/length codes can be 8 or 9 bits. |
| (The EOB code is shorter than other codes because fixed blocks are |
| generally short. So, while a block always has an EOB, many other |
| literal/length codes have a significantly lower probability of |
| 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. |
| */ |
| |
| static ush mask_bits[] = |
| { |
| 0x0000, |
| 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, |
| 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff |
| }; |
| |
| #pragma GCC diagnostic ignored "-Wunsafe-loop-optimizations" |
| |
| #define NEEDBITS(n) do {while(k<(n)){b|=((ulg)get_byte(gzio))<<k;k+=8;}} while (0) |
| #define DUMPBITS(n) do {b>>=(n);k-=(n);} while (0) |
| |
| static int |
| get_byte (grub_gzio_t gzio) |
| { |
| if (gzio->mem_input) |
| { |
| if (gzio->mem_input_off < gzio->mem_input_size) |
| return gzio->mem_input[gzio->mem_input_off++]; |
| return 0; |
| } |
| |
| if (gzio->file && (grub_file_tell (gzio->file) |
| == (grub_off_t) gzio->data_offset |
| || gzio->inbuf_d == INBUFSIZ)) |
| { |
| gzio->inbuf_d = 0; |
| grub_file_read (gzio->file, gzio->inbuf, INBUFSIZ); |
| } |
| |
| return gzio->inbuf[gzio->inbuf_d++]; |
| } |
| |
| static void |
| gzio_seek (grub_gzio_t gzio, grub_off_t off) |
| { |
| if (gzio->mem_input) |
| { |
| if (off > gzio->mem_input_size) |
| grub_error (GRUB_ERR_OUT_OF_RANGE, |
| N_("attempt to seek outside of the file")); |
| else |
| gzio->mem_input_off = off; |
| } |
| else |
| grub_file_seek (gzio->file, off); |
| } |
| |
| /* more function prototypes */ |
| static int huft_build (unsigned *, unsigned, unsigned, ush *, ush *, |
| struct huft **, int *); |
| static int huft_free (struct huft *); |
| 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 |
| huft_build (unsigned *b, /* code lengths in bits (all assumed <= BMAX) */ |
| 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 c[BMAX + 1]; /* bit length count table */ |
| 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 */ |
| struct huft *u[BMAX]; /* table stack */ |
| unsigned v[N_MAX]; /* values in order of bit length */ |
| register int w; /* bits before this table == (l * h) */ |
| unsigned x[BMAX + 1]; /* bit offsets, then code stack */ |
| unsigned *xp; /* pointer into x */ |
| 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 */ |
| { |
| *t = (struct huft *) NULL; |
| *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) */ |
| u[0] = (struct huft *) NULL; /* just to keep compilers happy */ |
| q = (struct huft *) NULL; /* ditto */ |
| 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 */ |
| q = (struct huft *) grub_malloc ((z + 1) * sizeof (struct huft)); |
| if (! q) |
| { |
| if (h) |
| huft_free (u[0]); |
| return 3; |
| } |
| |
| *t = q + 1; /* link to list for huft_free() */ |
| *(t = &(q->v.t)) = (struct huft *) NULL; |
| 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.e = (uch) (16 + j); /* bits in 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.e = (uch) (*p < 256 ? 16 : 15); /* 256 is end-of-block code */ |
| 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 |
| huft_free (struct huft *t) |
| { |
| register struct huft *p, *q; |
| |
| |
| /* Go through linked list, freeing from the malloced (t[-1]) address. */ |
| p = t; |
| while (p != (struct huft *) NULL) |
| { |
| 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 |
| inflate_codes_in_window (grub_gzio_t gzio) |
| { |
| register unsigned e; /* table entry flag/number of extra bits */ |
| unsigned n, d; /* length and index for copy */ |
| unsigned w; /* current window position */ |
| struct huft *t; /* pointer to table entry */ |
| unsigned ml, md; /* masks for bl and bd bits */ |
| register ulg b; /* bit buffer */ |
| register unsigned k; /* number of bits in bit buffer */ |
| |
| /* make local copies of globals */ |
| d = gzio->inflate_d; |
| n = gzio->inflate_n; |
| b = gzio->bb; /* initialize bit buffer */ |
| k = gzio->bk; |
| w = gzio->wp; /* initialize window position */ |
| |
| /* inflate the coded data */ |
| ml = mask_bits[gzio->bl]; /* precompute masks for speed */ |
| md = mask_bits[gzio->bd]; |
| for (;;) /* do until end of block */ |
| { |
| if (! gzio->code_state) |
| { |
| NEEDBITS ((unsigned) gzio->bl); |
| if ((e = (t = gzio->tl + ((unsigned) b & ml))->e) > 16) |
| do |
| { |
| if (e == 99) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, |
| "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 */ |
| { |
| gzio->slide[w++] = (uch) t->v.n; |
| if (w == WSIZE) |
| break; |
| } |
| else |
| /* it's an EOB or a length */ |
| { |
| /* exit if end of block */ |
| if (e == 15) |
| { |
| gzio->block_len = 0; |
| 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 */ |
| NEEDBITS ((unsigned) gzio->bd); |
| if ((e = (t = gzio->td + ((unsigned) b & md))->e) > 16) |
| do |
| { |
| if (e == 99) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, |
| "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 |
| { |
| n -= (e = (e = WSIZE - ((d &= WSIZE - 1) > w ? d : w)) > n ? n |
| : e); |
| |
| if (w - d >= e) |
| { |
| grub_memmove (gzio->slide + w, gzio->slide + d, e); |
| w += e; |
| d += e; |
| } |
| else |
| /* purposefully use the overlap for extra copies here!! */ |
| { |
| while (e--) |
| gzio->slide[w++] = gzio->slide[d++]; |
| } |
| |
| 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 */ |
| gzio->inflate_d = d; |
| gzio->inflate_n = n; |
| gzio->wp = w; /* restore global window pointer */ |
| gzio->bb = b; /* restore global bit buffer */ |
| gzio->bk = k; |
| |
| return ! gzio->block_len; |
| } |
| |
| |
| /* get header for an inflated type 0 (stored) block. */ |
| |
| static void |
| init_stored_block (grub_gzio_t gzio) |
| { |
| register ulg b; /* bit buffer */ |
| register unsigned k; /* number of bits in bit buffer */ |
| |
| /* make local copies of globals */ |
| b = gzio->bb; /* initialize bit buffer */ |
| k = gzio->bk; |
| |
| /* go to byte boundary */ |
| DUMPBITS (k & 7); |
| |
| /* get the length and its complement */ |
| NEEDBITS (16); |
| gzio->block_len = ((unsigned) b & 0xffff); |
| DUMPBITS (16); |
| NEEDBITS (16); |
| if (gzio->block_len != (int) ((~b) & 0xffff)) |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, |
| "the length of a stored block does not match"); |
| DUMPBITS (16); |
| |
| /* restore global variables */ |
| gzio->bb = b; |
| gzio->bk = k; |
| } |
| |
| |
| /* 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 |
| init_fixed_block (grub_gzio_t gzio) |
| { |
| 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; |
| gzio->bl = 7; |
| if (huft_build (l, 288, 257, cplens, cplext, &gzio->tl, &gzio->bl) != 0) |
| { |
| if (grub_errno == GRUB_ERR_NONE) |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, |
| "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; |
| gzio->bd = 5; |
| if (huft_build (l, 30, 0, cpdist, cpdext, &gzio->td, &gzio->bd) > 1) |
| { |
| if (grub_errno == GRUB_ERR_NONE) |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, |
| "failed in building a Huffman code table"); |
| huft_free (gzio->tl); |
| gzio->tl = 0; |
| return; |
| } |
| |
| /* indicate we're now working on a block */ |
| gzio->code_state = 0; |
| gzio->block_len++; |
| } |
| |
| |
| /* get header for an inflated type 2 (dynamic Huffman codes) block. */ |
| |
| static void |
| init_dynamic_block (grub_gzio_t gzio) |
| { |
| int i; /* temporary variables */ |
| unsigned j; |
| unsigned l; /* last length */ |
| unsigned m; /* mask for bit lengths table */ |
| unsigned n; /* number of lengths to get */ |
| unsigned nb; /* number of bit length codes */ |
| unsigned nl; /* number of literal/length codes */ |
| unsigned nd; /* number of distance codes */ |
| unsigned ll[286 + 30]; /* literal/length and distance code lengths */ |
| register ulg b; /* bit buffer */ |
| register unsigned k; /* number of bits in bit buffer */ |
| |
| /* make local bit buffer */ |
| b = gzio->bb; |
| k = gzio->bk; |
| |
| /* read in table lengths */ |
| NEEDBITS (5); |
| nl = 257 + ((unsigned) b & 0x1f); /* number of literal/length codes */ |
| DUMPBITS (5); |
| NEEDBITS (5); |
| nd = 1 + ((unsigned) b & 0x1f); /* number of distance codes */ |
| DUMPBITS (5); |
| NEEDBITS (4); |
| nb = 4 + ((unsigned) b & 0xf); /* number of bit length codes */ |
| DUMPBITS (4); |
| if (nl > 286 || nd > 30) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, "too much data"); |
| return; |
| } |
| |
| /* read in bit-length-code lengths */ |
| for (j = 0; j < nb; j++) |
| { |
| NEEDBITS (3); |
| ll[bitorder[j]] = (unsigned) b & 7; |
| DUMPBITS (3); |
| } |
| for (; j < 19; j++) |
| ll[bitorder[j]] = 0; |
| |
| /* build decoding table for trees--single level, 7 bit lookup */ |
| gzio->bl = 7; |
| if (huft_build (ll, 19, 19, NULL, NULL, &gzio->tl, &gzio->bl) != 0) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, |
| "failed in building a Huffman code table"); |
| return; |
| } |
| |
| /* read in literal and distance code lengths */ |
| n = nl + nd; |
| m = mask_bits[gzio->bl]; |
| i = l = 0; |
| while ((unsigned) i < n) |
| { |
| NEEDBITS ((unsigned) gzio->bl); |
| j = (gzio->td = gzio->tl + ((unsigned) b & m))->b; |
| DUMPBITS (j); |
| j = gzio->td->v.n; |
| 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) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, "too many codes found"); |
| 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) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, "too many codes found"); |
| 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) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, "too many codes found"); |
| return; |
| } |
| while (j--) |
| ll[i++] = 0; |
| l = 0; |
| } |
| } |
| |
| /* free decoding table for trees */ |
| huft_free (gzio->tl); |
| gzio->td = 0; |
| gzio->tl = 0; |
| |
| /* restore the global bit buffer */ |
| gzio->bb = b; |
| gzio->bk = k; |
| |
| /* build the decoding tables for literal/length and distance codes */ |
| gzio->bl = lbits; |
| if (huft_build (ll, nl, 257, cplens, cplext, &gzio->tl, &gzio->bl) != 0) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, |
| "failed in building a Huffman code table"); |
| return; |
| } |
| gzio->bd = dbits; |
| if (huft_build (ll + nl, nd, 0, cpdist, cpdext, &gzio->td, &gzio->bd) != 0) |
| { |
| huft_free (gzio->tl); |
| gzio->tl = 0; |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, |
| "failed in building a Huffman code table"); |
| return; |
| } |
| |
| /* indicate we're now working on a block */ |
| gzio->code_state = 0; |
| gzio->block_len++; |
| } |
| |
| |
| static void |
| get_new_block (grub_gzio_t gzio) |
| { |
| register ulg b; /* bit buffer */ |
| register unsigned k; /* number of bits in bit buffer */ |
| |
| /* make local bit buffer */ |
| b = gzio->bb; |
| k = gzio->bk; |
| |
| /* read in last block bit */ |
| NEEDBITS (1); |
| gzio->last_block = (int) b & 1; |
| DUMPBITS (1); |
| |
| /* read in block type */ |
| NEEDBITS (2); |
| gzio->block_type = (unsigned) b & 3; |
| DUMPBITS (2); |
| |
| /* restore the global bit buffer */ |
| gzio->bb = b; |
| gzio->bk = k; |
| |
| switch (gzio->block_type) |
| { |
| case INFLATE_STORED: |
| init_stored_block (gzio); |
| break; |
| case INFLATE_FIXED: |
| init_fixed_block (gzio); |
| break; |
| case INFLATE_DYNAMIC: |
| init_dynamic_block (gzio); |
| break; |
| default: |
| break; |
| } |
| } |
| |
| |
| static void |
| inflate_window (grub_gzio_t gzio) |
| { |
| /* initialize window */ |
| gzio->wp = 0; |
| |
| /* |
| * Main decompression loop. |
| */ |
| |
| while (gzio->wp < WSIZE && grub_errno == GRUB_ERR_NONE) |
| { |
| if (! gzio->block_len) |
| { |
| if (gzio->last_block) |
| break; |
| |
| get_new_block (gzio); |
| } |
| |
| if (gzio->block_type > INFLATE_DYNAMIC) |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, |
| "unknown block type %d", gzio->block_type); |
| |
| if (grub_errno != GRUB_ERR_NONE) |
| return; |
| |
| /* |
| * Expand stored block here. |
| */ |
| if (gzio->block_type == INFLATE_STORED) |
| { |
| int w = gzio->wp; |
| |
| /* |
| * This is basically a glorified pass-through |
| */ |
| |
| while (gzio->block_len && w < WSIZE && grub_errno == GRUB_ERR_NONE) |
| { |
| gzio->slide[w++] = get_byte (gzio); |
| gzio->block_len--; |
| } |
| |
| gzio->wp = w; |
| |
| continue; |
| } |
| |
| /* |
| * Expand other kind of block. |
| */ |
| |
| if (inflate_codes_in_window (gzio)) |
| { |
| huft_free (gzio->tl); |
| huft_free (gzio->td); |
| gzio->tl = 0; |
| gzio->td = 0; |
| } |
| } |
| |
| gzio->saved_offset += WSIZE; |
| |
| /* XXX do CRC calculation here! */ |
| } |
| |
| |
| static void |
| initialize_tables (grub_gzio_t gzio) |
| { |
| gzio->saved_offset = 0; |
| gzio_seek (gzio, gzio->data_offset); |
| |
| /* Initialize the bit buffer. */ |
| gzio->bk = 0; |
| gzio->bb = 0; |
| |
| /* Reset partial decompression code. */ |
| gzio->last_block = 0; |
| gzio->block_len = 0; |
| |
| /* Reset memory allocation stuff. */ |
| huft_free (gzio->tl); |
| huft_free (gzio->td); |
| } |
| |
| |
| /* 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 |
| grub_gzio_open (grub_file_t io) |
| { |
| grub_file_t file; |
| grub_gzio_t gzio = 0; |
| |
| file = (grub_file_t) grub_malloc (sizeof (*file)); |
| if (! file) |
| return 0; |
| |
| gzio = grub_zalloc (sizeof (*gzio)); |
| if (! gzio) |
| { |
| grub_free (file); |
| return 0; |
| } |
| |
| gzio->file = io; |
| |
| file->device = io->device; |
| file->offset = 0; |
| file->data = gzio; |
| file->read_hook = 0; |
| file->fs = &grub_gzio_fs; |
| file->not_easily_seekable = 1; |
| |
| if (! test_gzip_header (file)) |
| { |
| grub_errno = GRUB_ERR_NONE; |
| grub_free (gzio); |
| grub_free (file); |
| grub_file_seek (io, 0); |
| |
| return io; |
| } |
| |
| return file; |
| } |
| |
| static int |
| test_zlib_header (grub_gzio_t gzio) |
| { |
| grub_uint8_t cmf, flg; |
| |
| cmf = get_byte (gzio); |
| flg = get_byte (gzio); |
| |
| /* Check that compression method is DEFLATE. */ |
| if ((cmf & 0xf) != DEFLATED) |
| { |
| /* TRANSLATORS: It's about given file having some strange format, not |
| complete lack of gzip support. */ |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, N_("unsupported gzip format")); |
| return 0; |
| } |
| |
| if ((cmf * 256 + flg) % 31) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, N_("unsupported gzip format")); |
| return 0; |
| } |
| |
| /* Dictionary isn't supported. */ |
| if (flg & 0x20) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, N_("unsupported gzip format")); |
| return 0; |
| } |
| |
| gzio->data_offset = 2; |
| initialize_tables (gzio); |
| |
| return 1; |
| } |
| |
| static grub_ssize_t |
| grub_gzio_read_real (grub_gzio_t gzio, grub_off_t offset, |
| char *buf, grub_size_t len) |
| { |
| grub_ssize_t ret = 0; |
| |
| /* Do we reset decompression to the beginning of the file? */ |
| if (gzio->saved_offset > offset + WSIZE) |
| initialize_tables (gzio); |
| |
| /* |
| * 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. |
| */ |
| |
| while (len > 0 && grub_errno == GRUB_ERR_NONE) |
| { |
| register grub_size_t size; |
| register char *srcaddr; |
| |
| while (offset >= gzio->saved_offset) |
| inflate_window (gzio); |
| |
| srcaddr = (char *) ((offset & (WSIZE - 1)) + gzio->slide); |
| size = gzio->saved_offset - offset; |
| if (size > len) |
| size = len; |
| |
| grub_memmove (buf, srcaddr, size); |
| |
| buf += size; |
| len -= size; |
| ret += size; |
| offset += size; |
| } |
| |
| if (grub_errno != GRUB_ERR_NONE) |
| ret = -1; |
| |
| return ret; |
| } |
| |
| static grub_ssize_t |
| grub_gzio_read (grub_file_t file, char *buf, grub_size_t len) |
| { |
| return grub_gzio_read_real (file->data, file->offset, buf, len); |
| } |
| |
| /* Release everything, including the underlying file object. */ |
| static grub_err_t |
| grub_gzio_close (grub_file_t file) |
| { |
| grub_gzio_t gzio = file->data; |
| |
| grub_file_close (gzio->file); |
| huft_free (gzio->tl); |
| huft_free (gzio->td); |
| grub_free (gzio); |
| |
| /* No need to close the same device twice. */ |
| file->device = 0; |
| |
| return grub_errno; |
| } |
| |
| grub_ssize_t |
| grub_zlib_decompress (char *inbuf, grub_size_t insize, grub_off_t off, |
| char *outbuf, grub_size_t outsize) |
| { |
| grub_gzio_t gzio = 0; |
| grub_ssize_t ret; |
| |
| gzio = grub_zalloc (sizeof (*gzio)); |
| if (! gzio) |
| return -1; |
| gzio->mem_input = (grub_uint8_t *) inbuf; |
| gzio->mem_input_size = insize; |
| gzio->mem_input_off = 0; |
| |
| if (!test_zlib_header (gzio)) |
| { |
| grub_free (gzio); |
| return -1; |
| } |
| |
| ret = grub_gzio_read_real (gzio, off, outbuf, outsize); |
| grub_free (gzio); |
| |
| /* FIXME: Check Adler. */ |
| return ret; |
| } |
| |
| |
| |
| static struct grub_fs grub_gzio_fs = |
| { |
| .name = "gzio", |
| .dir = 0, |
| .open = 0, |
| .read = grub_gzio_read, |
| .close = grub_gzio_close, |
| .label = 0, |
| .next = 0 |
| }; |
| |
| GRUB_MOD_INIT(gzio) |
| { |
| grub_file_filter_register (GRUB_FILE_FILTER_GZIO, grub_gzio_open); |
| } |
| |
| GRUB_MOD_FINI(gzio) |
| { |
| grub_file_filter_unregister (GRUB_FILE_FILTER_GZIO); |
| } |