From 00b98c9b2ef86d4cc4254dd163798388fc1f4d52 Mon Sep 17 00:00:00 2001 From: Szymon Janc Date: Tue, 23 Aug 2011 19:49:01 +0200 Subject: [PATCH] * grub-core/fs/btrfs.c (grub_btrfs_lzo_decompress): Random fixes and some cleanup. --- grub-core/fs/btrfs.c | 120 ++++++++++++++++++++----------------------- 1 file changed, 56 insertions(+), 64 deletions(-) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index 7af735630..ae1ce1c7d 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -31,7 +31,17 @@ GRUB_MOD_LICENSE ("GPLv3+"); #define GRUB_BTRFS_SIGNATURE "_BHRfS_M" + +/* From http://www.oberhumer.com/opensource/lzo/lzofaq.php + * LZO will expand incompressible data by a little amount. I still haven't + * computed the exact values, but I suggest using these formulas for + * a worst-case expansion calculation: + * + * output_block_size = input_block_size + (input_block_size / 16) + 64 + 3 + * */ #define GRUB_BTRFS_LZO_BLOCK_SIZE 4096 +#define GRUB_BTRFS_LZO_BLOCK_MAX_CSIZE (GRUB_BTRFS_LZO_BLOCK_SIZE + \ + (GRUB_BTRFS_LZO_BLOCK_SIZE / 16) + 64 + 3) typedef grub_uint8_t grub_btrfs_checksum_t[0x20]; typedef grub_uint16_t grub_btrfs_uuid_t[8]; @@ -880,11 +890,11 @@ grub_btrfs_read_inode (struct grub_btrfs_data *data, return grub_btrfs_read_logical (data, elemaddr, inode, sizeof (*inode)); } -static int +static grub_ssize_t grub_btrfs_lzo_decompress(char *ibuf, grub_size_t isize, grub_off_t off, char *obuf, grub_size_t osize) { - grub_uint32_t total_size, cblock_size; + grub_uint32_t total_size, cblock_size, uncompressed = 0; unsigned char buf[GRUB_BTRFS_LZO_BLOCK_SIZE]; total_size = grub_le_to_cpu32 (grub_get_unaligned32 (ibuf)); @@ -893,62 +903,54 @@ grub_btrfs_lzo_decompress(char *ibuf, grub_size_t isize, grub_off_t off, if (isize < total_size) return -1; - while (osize != 0) + /* Jump forward to first block with requested data. */ + while (off >= GRUB_BTRFS_LZO_BLOCK_SIZE) + { + cblock_size = grub_le_to_cpu32 (grub_get_unaligned32 (ibuf)); + ibuf += sizeof (cblock_size); + + off -= GRUB_BTRFS_LZO_BLOCK_SIZE; + ibuf += cblock_size; + } + + while (osize > 0) { lzo_uint usize = GRUB_BTRFS_LZO_BLOCK_SIZE; cblock_size = grub_le_to_cpu32 (grub_get_unaligned32 (ibuf)); ibuf += sizeof (cblock_size); - if (cblock_size > GRUB_BTRFS_LZO_BLOCK_SIZE) - return -1; - - /* Jump forward to first block with requested data. */ - if (off >= GRUB_BTRFS_LZO_BLOCK_SIZE) + /* Block partially filled with requested data. */ + if (off > 0 || osize < GRUB_BTRFS_LZO_BLOCK_SIZE) { - off -= GRUB_BTRFS_LZO_BLOCK_SIZE; - ibuf += cblock_size; - continue; - } + grub_size_t to_copy = grub_min(osize, GRUB_BTRFS_LZO_BLOCK_SIZE - off); - /* First block partially filled with requested data. */ - if (off > 0) - { if (lzo1x_decompress_safe ((lzo_bytep)ibuf, cblock_size, buf, &usize, NULL) != LZO_E_OK) return -1; - grub_memcpy(obuf, buf + off, usize - off); + grub_memcpy(obuf, buf + off, to_copy); - osize -= usize - off; - obuf += usize - off; + osize -= to_copy; + uncompressed += to_copy; + obuf += to_copy; ibuf += cblock_size; off = 0; continue; } /* 'Main' case, decompress whole block directly to output buffer. */ - if (osize >= GRUB_BTRFS_LZO_BLOCK_SIZE) - { - if (lzo1x_decompress_safe ((lzo_bytep)ibuf, cblock_size, - (lzo_bytep)obuf, &usize, NULL) != LZO_E_OK) - return -1; + if (lzo1x_decompress_safe ((lzo_bytep)ibuf, cblock_size, (lzo_bytep)obuf, + &usize, NULL) != LZO_E_OK) + return -1; - osize -= usize; - obuf += usize; - ibuf += cblock_size; - } - else /* Last possible block partially filled with requested data. */ - { - if (lzo1x_decompress_safe ((lzo_bytep)ibuf, cblock_size, buf, &usize, - NULL) != LZO_E_OK) - return -1; - - grub_memcpy(obuf, buf, osize); - break; - } + osize -= usize; + uncompressed += usize; + obuf += usize; + ibuf += cblock_size; } - return 0; + + return uncompressed; } static grub_ssize_t @@ -1060,7 +1062,8 @@ grub_btrfs_extent_read (struct grub_btrfs_data *data, if (grub_btrfs_lzo_decompress(data->extent->inl, data->extsize - ((grub_uint8_t *) data->extent->inl - (grub_uint8_t *) data->extent), - extoff, buf, csize) < 0) + extoff, buf, csize) + != (grub_ssize_t) csize) return -1; } else @@ -1075,8 +1078,10 @@ grub_btrfs_extent_read (struct grub_btrfs_data *data, if (data->extent->compression != GRUB_BTRFS_COMPRESSION_NONE) { - void *tmp; + char *tmp; grub_uint64_t zsize; + grub_ssize_t ret; + zsize = grub_le_to_cpu64 (data->extent->compressed_size); tmp = grub_malloc (zsize); if (!tmp) @@ -1091,36 +1096,23 @@ grub_btrfs_extent_read (struct grub_btrfs_data *data, } if (data->extent->compression == GRUB_BTRFS_COMPRESSION_ZLIB) - { - grub_ssize_t ret; - - ret = grub_zlib_decompress (tmp, zsize, extoff - + grub_le_to_cpu64 (data->extent->offset), - buf, csize); - - grub_free (tmp); - - if (ret != (grub_ssize_t) csize) - return -1; - - break; - } - else if (data->extent->compression == GRUB_BTRFS_COMPRESSION_LZO) - { - int ret ; - - ret = grub_btrfs_lzo_decompress (tmp, zsize, extoff + ret = grub_zlib_decompress (tmp, zsize, extoff + grub_le_to_cpu64 (data->extent->offset), buf, csize); + else if (data->extent->compression == GRUB_BTRFS_COMPRESSION_LZO) + ret = grub_btrfs_lzo_decompress (tmp, zsize, extoff + + grub_le_to_cpu64 (data->extent->offset), + buf, csize); + else + ret = -1; - grub_free(tmp); + grub_free(tmp); - if (ret < 0) - return -1; + if (ret != (grub_ssize_t) csize) + return -1; - break; - } - } + break; + } err = grub_btrfs_read_logical (data, grub_le_to_cpu64 (data->extent->laddr) + grub_le_to_cpu64 (data->extent->offset)