Commit Graph

44 Commits

Author SHA1 Message Date
Kevin Wolf
3edf1e73d5 dmg: Implement .bdrv_co_preadv() interface
This implements .bdrv_co_preadv() for the cloop block driver. While
updating the error paths, change -1 to a valid -errno code.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
2016-05-12 15:22:08 +02:00
Markus Armbruster
da34e65cb4 include/qemu/osdep.h: Don't include qapi/error.h
Commit 57cb38b included qapi/error.h into qemu/osdep.h to get the
Error typedef.  Since then, we've moved to include qemu/osdep.h
everywhere.  Its file comment explains: "To avoid getting into
possible circular include dependencies, this file should not include
any other QEMU headers, with the exceptions of config-host.h,
compiler.h, os-posix.h and os-win32.h, all of which are doing a
similar job to this file and are under similar constraints."
qapi/error.h doesn't do a similar job, and it doesn't adhere to
similar constraints: it includes qapi-types.h.  That's in excess of
100KiB of crap most .c files don't actually need.

Add the typedef to qemu/typedefs.h, and include that instead of
qapi/error.h.  Include qapi/error.h in .c files that need it and don't
get it now.  Include qapi-types.h in qom/object.h for uint16List.

Update scripts/clean-includes accordingly.  Update it further to match
reality: replace config.h by config-target.h, add sysemu/os-posix.h,
sysemu/os-win32.h.  Update the list of includes in the qemu/osdep.h
comment quoted above similarly.

This reduces the number of objects depending on qapi/error.h from "all
of them" to less than a third.  Unfortunately, the number depending on
qapi-types.h shrinks only a little.  More work is needed for that one.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
[Fix compilation without the spice devel packages. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-22 22:20:15 +01:00
Peter Maydell
80c71a241a block: Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-01-20 13:36:23 +01:00
Kevin Wolf
9a4f4c3156 block: Convert bs->file to BdrvChild
This patch removes the temporary duplication between bs->file and
bs->file_child by converting everything to BdrvChild.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16 15:34:29 +02:00
Markus Armbruster
d49b683644 qerror: Move #include out of qerror.h
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
2015-06-22 18:20:40 +02:00
Peter Wu
177b75104d block/dmg: improve zeroes handling
Disk images may contain large all-zeroes gaps (1.66k sectors or 812 MiB
is seen in the real world). These blocks (type 2) do not need to be
extracted into a temporary buffer, there is no need to allocate memory
for these blocks nor to check its length.

(For the test image, the maximum uncompressed size is 1054371 bytes,
probably for a bzip2-compressed block.)

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-13-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Wu
6b383c08c4 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>
2015-02-06 17:24:21 +01:00
Peter Wu
a8b10c6ead block/dmg: factor out block type check
In preparation for adding bzip2 support, split the type check into a
separate function. Make all offsets relative to the begin of a chunk
such that it is easier to recognize the position without having to
add up all offsets. Some comments are added to describe the fields.

There is no functional change.

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-11-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Wu
66ec3bba97 block/dmg: use SectorNumber from BLKX header
Previously the sector table parsing relied on the previous offset of
the DMG file. Now it uses the sector number from the BLKX header
(see http://newosxbook.com/DMG.html).

The implementation of dmg2img (from vu1tur) does not base the output
sector on the location of the terminator (0xffffffff) either so it
should be safe to drop this dependency on the previous state.

(It makes somehow makes sense, a terminator should halt further
processing of a block and is perhaps used to preallocate some space.)

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-10-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Wu
c6d34865fa block/dmg: fix sector data offset calculation
This patch addresses two issues:

 - The data fork offset was not taken into account, resulting in failure
   to read an InstallESD.dmg file (5164763151 bytes) which had a
   non-zero DataForkOffset field.
 - The offset of the previous block ("partition") was unconditionally
   added to the current block because older files would start the input
   offset of a new block at zero. Newer files (including vlc-2.1.5.dmg,
   tuxpaint-0.9.15-macosx.dmg and OS X Yosemite [MAS].dmg) failed in
   reads because these files have chunk offsets, relative to the begin
   of a data fork.

Now the data offset of the mish is taken into account. While we could
check that the data_offset is within the data fork, let's not do that
here as it would only result in parse failures on invalid files (rather
than gracefully handling such bad files). dmg_read will error out if
the offset is incorrect.

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-9-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Wu
8daf425794 block/dmg: set virtual size to a non-zero value
Right now the virtual size is always reported as zero which makes it
impossible to convert between formats.

After this patch, the number of sectors will be read from the trailer
("koly" block).

To verify the behavior, the output of `dmg2img foo.dmg foo.img` was
compared against `qemu-img convert -f dmg -O raw foo.dmg foo.raw`. The
tests showed that the file contents are exactly the same, except that
QEMU creates a slightly larger file (it matches the total sectors
count).

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-8-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Wu
0599e56ed4 block/dmg: process XML plists
The format is simple enough to avoid using a full-blown XML parser. It
assumes that all BLKX items begin with the "mish" magic word, therefore
it is not a problem if other values get matched which are not a BLKX
block.

The offsets are based on the description at
http://newosxbook.com/DMG.html

For compatibility with glib 2.12, use g_base64_decode (which
additionally requires an extra buffer allocation) instead of
g_base64_decode_inplace (which is only available since glib 2.20).

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-7-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Wu
f6e6652d7c block/dmg: validate chunk size to avoid overflow
Previously the chunk size was not checked, allowing for a large memory
allocation. This patch checks whether the chunks size is within the
resource fork length, and whether the resource fork is below the
trailer of the dmg file.

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-6-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Wu
7aee37b93a block/dmg: process a buffer instead of reading ints
As the decoded plist XML is not a pointer in the file,
dmg_read_mish_block must be able to process a buffer instead of a file
pointer. Since the full buffer must be processed, let's change the
return value again to just a success flag.

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-5-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Wu
b0e8dc5d54 block/dmg: extract processing of resource forks
Besides the offset, also read the resource length. This length is now
used in the extracted function to verify the end of the resource fork
against "count" from the resource fork.

Instead of relying on the value of offset to conclude whether the
resource fork is available or not (info_begin==0), check the
rsrc_fork_length instead. This would allow a dmg file to begin with a
resource fork. This seemingly unnecessary restriction was found while
trying to craft a DMG file by hand.

Other changes:

 - Do not require resource data offset to be 0x100 (but check that it
   is within bounds though).
 - Further improve boundary checking (resource data must be within
   the resource fork).
 - Use correct value for resource data length (spotted by John Snow)
 - Consider the resource data offset when determining info_end.
   This fixes an EINVAL on the tuxpaint dmg example.

The resource fork format is documented at
https://developer.apple.com/legacy/library/documentation/mac/pdf/MoreMacintoshToolbox.pdf#page=151

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-4-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Wu
65a1c7c96a block/dmg: extract mish block decoding functionality
Extract the mish block decoder such that this can be used for other
formats in the future. A new DmgHeaderState struct is introduced to
share state while decoding.

The code is kept unchanged as much as possible, a "fail" label is added
for example where a simple return would probably do. In dmg_open, the
variable "tmp" is renamed to "rsrc_data_offset" for clarity and comments
have been added explaining various data.

Note that this patch has one subtle difference with the previous
version which should not affect functionality. In the previous code,
the end of a resource was inferred from the mish block (the offsets
would be increased by the fields). In this patch, the resource length
is used instead to avoid the need to rely on the previous offsets.

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1420566495-13284-3-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Peter Wu
fa8354bd22 block/dmg: properly detect the UDIF trailer
DMG files have a variable length with a UDIF trailer at the end of a
file. This UDIF trailer is essential as it describes the contents of
the image. At the moment however, the start of this trailer is almost
always incorrect as bdrv_getlength() returns a multiple of the block
size (rounded up). This results in a failure to recognize DMG files,
resulting in Invalid argument (EINVAL) errors.

As there is no API to retrieve the real file size, look for the magic
header in the last two sectors to find the start of this 512-byte UDIF
trailer (the "koly" block).

The resource fork offset ("info_begin") has its offset adjusted as the
initial value of offset does not mean "end of file" anymore, but "begin
of UDIF trailer".

[Replaced error_set(errp, ERROR_CLASS_GENERIC_ERROR, ...) with
error_setg(errp, ...) as discussed with Peter.
--Stefan]

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1420566495-13284-2-git-send-email-peter@lekensteyn.nl
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-02-06 17:24:21 +01:00
Kevin Wolf
b546a94474 dmg: Handle failure for potentially large allocations
Some code in the block layer makes potentially huge allocations. Failure
is not completely unexpected there, so avoid aborting qemu and handle
out-of-memory situations gracefully.

This patch addresses the allocations in the dmg block driver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15 15:07:15 +02:00
Max Reitz
521b2b5df0 block: Use correct width in format strings
Instead of blindly relying on a normal integer having a width of 32 bits
(which is a pretty good assumption, but we should not rely on it if
there is no need), use the correct format string macros.

This does not touch DEBUG output.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-04-30 14:46:17 +02:00
Stefan Hajnoczi
f0dce23475 dmg: prevent chunk buffer overflow (CVE-2014-0145)
Both compressed and uncompressed I/O is buffered.  dmg_open() calculates
the maximum buffer size needed from the metadata in the image file.

There is currently a buffer overflow since ->lengths[] is accounted
against the maximum compressed buffer size but actually uses the
uncompressed buffer:

  switch (s->types[chunk]) {
  case 1: /* copy */
      ret = bdrv_pread(bs->file, s->offsets[chunk],
                       s->uncompressed_chunk, s->lengths[chunk]);

We must account against the maximum uncompressed buffer size for type=1
chunks.

This patch fixes the maximum buffer size calculation to take into
account the chunk type.  It is critical that we update the correct
maximum since there are two buffers ->compressed_chunk and
->uncompressed_chunk.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01 15:22:35 +02:00
Stefan Hajnoczi
686d7148ec dmg: use uint64_t consistently for sectors and lengths
The DMG metadata is stored as uint64_t, so use the same type for
sector_num.  int was a particularly poor choice since it is only 32-bit
and would truncate large values.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01 15:22:35 +02:00
Stefan Hajnoczi
c165f77580 dmg: sanitize chunk length and sectorcount (CVE-2014-0145)
Chunk length and sectorcount are used for decompression buffers as well
as the bdrv_pread() count argument.  Ensure that they have reasonable
values so neither memory allocation nor conversion from uint64_t to int
will cause problems.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01 15:22:35 +02:00
Stefan Hajnoczi
eb71803b04 dmg: use appropriate types when reading chunks
Use the right types instead of signed int:

  size_t new_size;

  This is a byte count for g_realloc() that is calculated from uint32_t
  and size_t values.

  uint32_t chunk_count;

  Use the same type as s->n_chunks, which is used together with
  chunk_count.

This patch is a cleanup and does not fix bugs.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01 15:22:35 +02:00
Stefan Hajnoczi
b404bf8542 dmg: drop broken bdrv_pread() loop
It is not necessary to check errno for EINTR and the block layer does
not produce short reads.  Therefore we can drop the loop that attempts
to read a compressed chunk.

The loop is buggy because it incorrectly adds the transferred bytes
twice:

  do {
      ret = bdrv_pread(...);
      i += ret;
  } while (ret >= 0 && ret + i < s->lengths[chunk]);

Luckily we can drop the loop completely and perform a single
bdrv_pread().

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01 15:22:35 +02:00
Stefan Hajnoczi
73ed27ec28 dmg: prevent out-of-bounds array access on terminator
When a terminator is reached the base for offsets and sectors is stored.
The following records that are processed will use this base value.

If the first record we encounter is a terminator, then calculating the
base values would result in out-of-bounds array accesses.  Don't do
that.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01 15:22:35 +02:00
Stefan Hajnoczi
2c1885adcf dmg: coding style and indentation cleanup
Clean up the mix of tabs and spaces, as well as the coding style
violations in block/dmg.c.  There are no semantic changes since this
patch simply reformats the code.

This patch is necessary before we can make meaningful changes to this
file, due to the inconsistent formatting and confusing indentation.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-01 15:22:35 +02:00
Max Reitz
015a1036a7 bdrv: Use "Error" for opening images
Add an Error ** parameter to BlockDriver.bdrv_open and
BlockDriver.bdrv_file_open to allow more specific error messages.

Signed-off-by: Max Reitz <mreitz@redhat.com>
2013-09-12 10:12:47 +02:00
Kevin Wolf
f5866fa438 block: Make find_image_format safe with NULL filename
In order to achieve this, the .bdrv_probe callbacks of all drivers must
cope with this. The DMG driver is the only one that bases its decision
on the filename and it needs to be changed.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2013-03-22 17:51:32 +01:00
Kevin Wolf
1a86938f04 block: Add options QDict to .bdrv_open()
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-03-15 16:07:49 +01:00
Kevin Wolf
4f8aa2e19f dmg: Use g_free instead of free
The buffers are allocated with g_(re)alloc, so use g_free to free them.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-02-01 14:58:29 +01:00
Kevin Wolf
69d34a360d dmg: Fix bdrv_open() error handling
Return -errno instead of -1 on errors and add error checks in some
places that didn't have one. Passing things by reference requires more
correct typing, replaced a few off_ts therefore - with a 32-bit off_t
this is even a fix for truncation bugs.

While touching the code, fix even some more memory leaks than in the
other drivers...

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-02-01 14:58:29 +01:00
Paolo Bonzini
1de7afc984 misc: move include files to include/qemu/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:32:39 +01:00
Paolo Bonzini
737e150e89 block: move include files to include/block/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:31:31 +01:00
Paolo Bonzini
2914caa088 block: take lock around bdrv_read implementations
This does the first part of the conversion to coroutines, by
wrapping bdrv_read implementations to take the mutex.

Drivers that implement bdrv_read rather than bdrv_co_readv can
then benefit from asynchronous operation (at least if the underlying
protocol supports it, which is not the case for raw-win32), even
though they still operate with a bounce buffer.

raw-win32 does not need the lock, because it cannot yield.
nbd also doesn't probably, but better be safe.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-21 17:34:14 +02:00
Paolo Bonzini
848c66e8f5 block: add a CoMutex to synchronous read drivers
The big conversion of bdrv_read/write to coroutines caused the two
homonymous callbacks in BlockDriver to become reentrant.  It goes
like this:

1) bdrv_read is now called in a coroutine, and calls bdrv_read or
bdrv_pread.

2) the nested bdrv_read goes through the fast path in bdrv_rw_co_entry;

3) in the common case when the protocol is file, bdrv_co_do_readv calls
bdrv_co_readv_em (and from here goes to bdrv_co_io_em), which yields
until the AIO operation is complete;

4) if bdrv_read had been called from a bottom half, the main loop
is free to iterate again: a device model or another bottom half
can then come and call bdrv_read again.

This applies to all four of read/write/flush/discard.  It would also
apply to is_allocated, but it is not used from within coroutines:
besides qemu-img.c and qemu-io.c, which operate synchronously, the
only user is the monitor.  Copy-on-read will introduce a use in the
block layer, and will require converting it.

The solution is "simply" to convert all drivers to coroutines!  We
just need to add a CoMutex that is taken around affected operations.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-10-21 17:34:13 +02:00
Anthony Liguori
7267c0947d Use glib memory allocation and free functions
qemu_malloc/qemu_free no longer exist after this commit.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-08-20 23:01:08 -05:00
Christoph Hellwig
64a31d5c3d dmg: use qemu block API
Use bdrv_pwrite to access the backing device instead of pread, and
convert the driver to implementing the bdrv_open method which gives
it an already opened BlockDriverState for the underlying device.

Dmg actually does an lseek to a negative offset in the open routine,
which we replace with offset arithmetics after doing a bdrv_getlength.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-17 10:20:05 +02:00
Christoph Hellwig
16cdf7ce1a dmg: use pread
Use pread instead of lseek + read in preparation of using the qemu
block API.  Note that dmg actually uses the implicit file offset
a lot in dmg_open, and we had to replace it with an offset variable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-17 10:20:05 +02:00
Christoph Hellwig
cd02a24b61 dmg: fix reading of uncompressed chunks
When dmg_read_chunk encounters an uncompressed chunk it currently
calls read without any previous adjustment of the file postion.

This seems very wrong, and the "reference" implementation in
dmg2img does a search to the same offset as done in the various
compression cases, so do the same here.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-17 10:20:05 +02:00
Kevin Wolf
66f82ceed6 block: Open the underlying image file in generic code
Format drivers shouldn't need to bother with things like file names, but rather
just get an open BlockDriverState for the underlying protocol. This patch
introduces this behaviour for bdrv_open implementation. For protocols which
need to access the filename to open their file/device/connection/... a new
callback bdrv_file_open is introduced which doesn't get an underlying file
opened.

For now, also some of the more obscure formats use bdrv_file_open because they
open() the file themselves instead of using the block.c functions. They need to
be fixed in later patches.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-03 10:07:30 +02:00
Christoph Hellwig
1559ca00bc dmg: fix ->open failure
Currently the dmg image format driver simply opens the images as raw
if any kind of failure happens.  This is contrarty to the behaviour
of all other image formats which just return an error and let the
block core deal with it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-11 13:41:00 -06:00
Anthony Liguori
1cec71e359 Revert "support colon in filenames"
This reverts commit 707c0dbc97.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-07-09 16:06:38 -05:00
Ram Pai
707c0dbc97 support colon in filenames
Problem: It is impossible to feed filenames with the character colon because
qemu interprets such names as a protocol. For example filename scsi:0, is
interpreted as a protocol by name "scsi".

This patch allows user to espace colon characters. For example the above
filename can now be expressed either as 'scsi\:0' or as file:scsi:0

anything following the "file:" tag is interpreted verbatin. However if "file:"
tag is omitted then any colon characters in the string must be escaped using
backslash.

Here are couple of examples:

scsi\:0\:abc is a local file scsi:0:abc
http\://myweb is a local file by name http://myweb
file:scsi:0:abc is a local file scsi:0:abc
file:http://myweb is a local file by name http://myweb

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-06-29 13:50:05 -05:00
Anthony Liguori
019d6b8ff0 Move block drivers into their own directory
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-05-14 16:13:46 -05:00