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block/dmg: support bzip2 block entry types 

This patch adds support for bzip2-compressed block entries as introduced
with OS X 10.4 (source: https://en.wikipedia.org/wiki/Apple_Disk_Image).

It was tested against a 5.2G "OS X Yosemite" installation image which
stores the BLXX block in the XML property list (instead of resource
forks) and has over 5k chunks.

New configure entries are added (--enable-bzip2 / --disable-bzip2) to
control inclusion of bzip2 functionality (which requires linking against
libbz2). The help message suggests that this option is needed for DMG
files, but the tests are generic enough that other parts of QEMU can use
bzip2 if needed.

The identifiers are based on http://newosxbook.com/DMG.html.

The decompression routines are based on the zlib case, but as there is
no way to reset the decompression state (unlike zlib), memory is
allocated and deallocated for every decompression. This should not be
problematic as the decompression takes most of the time and as blocks
are typically about/over 1 MiB in size, only one allocation is done
every 2000 sectors.

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1420566495-13284-12-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Peter Wu 2015-01-06 18:48:14 +01:00 committed by Kevin Wolf
parent a8b10c6ead
commit 6b383c08c4
3 changed files with 74 additions and 1 deletions
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1
block/Makefile.objs
View File

@ -37,5 +37,6 @@ gluster.o-libs := $(GLUSTERFS_LIBS)
ssh.o-cflags := $(LIBSSH2_CFLAGS)
ssh.o-libs := $(LIBSSH2_LIBS)
archipelago.o-libs := $(ARCHIPELAGO_LIBS)
dmg.o-libs := $(BZIP2_LIBS)
qcow.o-libs := -lz
linux-aio.o-libs := -laio

43
block/dmg.c
View File

@ -26,6 +26,9 @@
#include "qemu/bswap.h"
#include "qemu/module.h"
#include <zlib.h>
#ifdef CONFIG_BZIP2
#include <bzlib.h>
#endif
#include <glib.h>
enum {
@ -56,6 +59,9 @@ typedef struct BDRVDMGState {
uint8_t *compressed_chunk;
uint8_t *uncompressed_chunk;
z_stream zstream;
#ifdef CONFIG_BZIP2
bz_stream bzstream;
#endif
} BDRVDMGState;
static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
@ -123,6 +129,7 @@ static void update_max_chunk_size(BDRVDMGState *s, uint32_t chunk,
switch (s->types[chunk]) {
case 0x80000005: /* zlib compressed */
case 0x80000006: /* bzip2 compressed */
compressed_size = s->lengths[chunk];
uncompressed_sectors = s->sectorcounts[chunk];
break;
@ -198,6 +205,9 @@ static bool dmg_is_known_block_type(uint32_t entry_type)
case 0x00000001: /* uncompressed */
case 0x00000002: /* zeroes */
case 0x80000005: /* zlib */
#ifdef CONFIG_BZIP2
case 0x80000006: /* bzip2 */
#endif
return true;
default:
return false;
@ -564,13 +574,16 @@ static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num)
if (!is_sector_in_chunk(s, s->current_chunk, sector_num)) {
int ret;
uint32_t chunk = search_chunk(s, sector_num);
#ifdef CONFIG_BZIP2
uint64_t total_out;
#endif
if (chunk >= s->n_chunks) {
return -1;
}
s->current_chunk = s->n_chunks;
switch (s->types[chunk]) {
switch (s->types[chunk]) { /* block entry type */
case 0x80000005: { /* zlib compressed */
/* we need to buffer, because only the chunk as whole can be
* inflated. */
@ -594,6 +607,34 @@ static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num)
return -1;
}
break; }
#ifdef CONFIG_BZIP2
case 0x80000006: /* bzip2 compressed */
/* we need to buffer, because only the chunk as whole can be
* inflated. */
ret = bdrv_pread(bs->file, s->offsets[chunk],
s->compressed_chunk, s->lengths[chunk]);
if (ret != s->lengths[chunk]) {
return -1;
}
ret = BZ2_bzDecompressInit(&s->bzstream, 0, 0);
if (ret != BZ_OK) {
return -1;
}
s->bzstream.next_in = (char *)s->compressed_chunk;
s->bzstream.avail_in = (unsigned int) s->lengths[chunk];
s->bzstream.next_out = (char *)s->uncompressed_chunk;
s->bzstream.avail_out = (unsigned int) 512 * s->sectorcounts[chunk];
ret = BZ2_bzDecompress(&s->bzstream);
total_out = ((uint64_t)s->bzstream.total_out_hi32 << 32) +
s->bzstream.total_out_lo32;
BZ2_bzDecompressEnd(&s->bzstream);
if (ret != BZ_STREAM_END ||
total_out != 512 * s->sectorcounts[chunk]) {
return -1;
}
break;
#endif /* CONFIG_BZIP2 */
case 1: /* copy */
ret = bdrv_pread(bs->file, s->offsets[chunk],
s->uncompressed_chunk, s->lengths[chunk]);

31
configure vendored
View File

@ -313,6 +313,7 @@ glx=""
zlib="yes"
lzo=""
snappy=""
bzip2=""
guest_agent=""
guest_agent_with_vss="no"
vss_win32_sdk=""
@ -1060,6 +1061,10 @@ for opt do
;;
--enable-snappy) snappy="yes"
;;
--disable-bzip2) bzip2="no"
;;
--enable-bzip2) bzip2="yes"
;;
--enable-guest-agent) guest_agent="yes"
;;
--disable-guest-agent) guest_agent="no"
@ -1374,6 +1379,8 @@ Advanced options (experts only):
--enable-usb-redir enable usb network redirection support
--enable-lzo enable the support of lzo compression library
--enable-snappy enable the support of snappy compression library
--enable-bzip2 enable the support of bzip2 compression library (for
reading bzip2-compressed dmg images)
--disable-guest-agent disable building of the QEMU Guest Agent
--enable-guest-agent enable building of the QEMU Guest Agent
--with-vss-sdk=SDK-path enable Windows VSS support in QEMU Guest Agent
@ -1819,6 +1826,24 @@ EOF
fi
fi
##########################################
# bzip2 check
if test "$bzip2" != "no" ; then
cat > $TMPC << EOF
#include <bzlib.h>
int main(void) { BZ2_bzlibVersion(); return 0; }
EOF
if compile_prog "" "-lbz2" ; then
bzip2="yes"
else
if test "$bzip2" = "yes"; then
feature_not_found "libbzip2" "Install libbzip2 devel"
fi
bzip2="no"
fi
fi
##########################################
# libseccomp check
@ -4385,6 +4410,7 @@ echo "vhdx $vhdx"
echo "Quorum $quorum"
echo "lzo support $lzo"
echo "snappy support $snappy"
echo "bzip2 support $bzip2"
echo "NUMA host support $numa"
if test "$sdl_too_old" = "yes"; then
@ -4743,6 +4769,11 @@ if test "$snappy" = "yes" ; then
echo "CONFIG_SNAPPY=y" >> $config_host_mak
fi
if test "$bzip2" = "yes" ; then
echo "CONFIG_BZIP2=y" >> $config_host_mak
echo "BZIP2_LIBS=-lbz2" >> $config_host_mak
fi
if test "$libiscsi" = "yes" ; then
echo "CONFIG_LIBISCSI=m" >> $config_host_mak
echo "LIBISCSI_CFLAGS=$libiscsi_cflags" >> $config_host_mak