Commit Graph

42866 Commits

Author SHA1 Message Date
Bo Tu
8a7607c2e2 qemu-iotests: refine common.config
Replacing awk with sed, then it's easier to read.
Replacing "[ ! -z "$default_alias_machine" ]" with
"[[ $default_alias_machine ]]", then it's slightly shorter.

Reviewed-by: Max Reitz <mreitz@redhat.com>
Suggested-By: Sascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: Eric Blake   <eblake@redhat.com>
Signed-off-by: Bo Tu <tubo@linux.vnet.ibm.com>
Message-id: 1449136891-26850-2-git-send-email-tubo@linux.vnet.ibm.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:36:17 +01:00
Paolo Bonzini
ba88944495 block: fix bdrv_ioctl called from coroutine
When called from a coroutine, bdrv_ioctl must be asynchronous just like
e.g. bdrv_flush.  The code was incorrectly making it synchronous, fix
it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:44 +01:00
Paolo Bonzini
27a7649a48 block: use drained section around bdrv_snapshot_delete
Do not use bdrv_drain, since by itself it does not guarantee
anything.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:44 +01:00
Fam Zheng
8382ba6153 iotests: Update comments for bdrv_swap() in 094
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:44 +01:00
Fam Zheng
bbe1ef2686 block: Remove prototype of bdrv_swap from header
The function has gone.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
d657c0c289 raw-posix: Make aio=native option binding
Traditionally, aio=native was treated as an advice that could simply be
ignored if an error occurs while initialising Linux AIO or the feature
wasn't compiled in. This behaviour was deprecated in commit 96518254
(qemu 2.3; error during init) and commit 1501ecc1 (qemu 2.5; not
compiled in).

This patch changes raw-posix to error out in these cases instead of
printing a deprecation warning.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-12-18 14:34:43 +01:00
Denis V. Lunev
b1fc8f934b qcow2: insert assert into qcow2_get_specific_info()
s->qcow_version is always set to 2 or 3. Let's assert if this is wrong.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Max Reitz <mreitz@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Max Reitz
e9dbdc5e46 iotests: Extend test 112 for qemu-img amend
Add tests for conversion between different refcount widths.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Max Reitz
03bb78ed25 qcow2: Point to amend function in check
If a reference count is not representable with the current refcount
order, the image check should point to qemu-img amend for increasing the
refcount order. However, qemu-img amend needs write access to the image
which cannot be provided if the image is marked corrupt; and the image
check will not mark the image consistent unless everything actually is
consistent.

Therefore, if an image is marked corrupt and the image check encounters
a reference count overflow, it cannot be fixed by using qemu-img amend
to increase the refcount order. Instead, one has to use qemu-img convert
to create a completely new copy of the image in this case.

Alternatively, we may want to give the user a way of manually removing
the corrupt flag, maybe through qemu-img amend, but this is not part of
this patch.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Max Reitz
61ce55fc02 qcow2: Invoke refcount order amendment function
Make use of qcow2_change_refcount_order() to support changing the
refcount order with qemu-img amend.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Max Reitz
791c9a004e qcow2: Add function for refcount order amendment
Add a function qcow2_change_refcount_order() which allows changing the
refcount order of a qcow2 image.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Max Reitz
c293a80927 qcow2: Use intermediate helper CB for amend
If there is more than one time-consuming operation to be performed for
qcow2_amend_options(), we need an intermediate CB which coordinates the
progress of the individual operations and passes the result to the
original status callback.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Max Reitz
1038bbb803 qcow2: Split upgrade/downgrade paths for amend
If the image version should be upgraded, that is the first we should do;
if it should be downgraded, that is the last we should do. So split the
version change block into an upgrade part at the start and a downgrade
part at the end.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Max Reitz
164e0f89cc qcow2: Use abort() instead of assert(false)
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Max Reitz
29d72431ef qcow2: Use error_report() in qcow2_amend_options()
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Max Reitz
8b13976d3f block: Add opaque value to the amend CB
Add an opaque value which is to be passed to the bdrv_amend_options()
status callback.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Max Reitz
bd5072d756 progress: Allow regressing progress
Progress may regress; this should be displayed correctly by
qemu_progress_print().

While touching that area of code, drop the redundant parentheses in the
same condition.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
0a8111e0fb qemu-iotests: Test reopen with node-name/driver options
'node-name' and 'driver' should not be changed during a reopen
operation. It is, however, valid to specify them with the same value as
they already had.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
8f7acbe6ea qemu-iotests: Test cache mode option inheritance
This is doing a more complete test on setting cache modes both while
opening an image (i.e. in a -drive command line) and in reopen
situations. It checks that reopen can specify options for child nodes
and that cache modes are correctly inherited from parent nodes where
they are not specified.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
768ee459f5 qemu-iotests: Try setting cache mode for children
This is a basic test for specifying cache modes for child nodes on the
command line. It doesn't take much time and works without O_DIRECT
support.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
c5e8bfb7cd blkdebug: Enable reopen
Just reopening the children (as block.c does now) is enough.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
91a097e747 block: Move cache options into options QDict
This adds the cache mode options to the QDict, so that they can be
specified for child nodes (e.g. backing.cache.direct=off).

The cache modes are not removed from the flags at this point; instead,
options and flags are kept in sync. If the user specifies both flags and
options, the options take precedence.

Child node inherit cache modes as options now, they don't use flags any
more.

Note that this forbids specifying the cache mode for empty drives. It
didn't make sense anyway to specify it there, because it didn't have any
effect. blockdev_init() considers the cache options now bdrv_open()
options and therefore doesn't create an empty drive any more but calls
into bdrv_open(). This in turn will fail with no driver and filename
specified.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
ccf9dc07b5 block: reopen: Extract QemuOpts for generic block layer options
This patch adds a QemuOpts for generic block layer options to
bdrv_reopen_prepare(). The only two options that currently exist
(node-name and driver) cannot be changed, so the only thing we do is
putting them right back into the QDict so that we check at the end that
they are indeed unchanged.

We will add new options soon that can actually be changed.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
fc17c25931 qemu-iotests: Remove cache mode test without medium
Specifying the cache mode for a driver without a medium is not a useful
thing to do: As long as there is no medium, the cache mode doesn't make
a difference, and once the 'change' command is used to insert a medium,
it ignores the old cache mode and makes the new medium use
cache=writethrough.

Later patches will make it an error to specify the cache mode for an
empty drive. Remove the corresponding test case.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
39c4ae941e blockdev: Set 'format' indicates non-empty drive
Creating an empty drive while specifying 'format' doesn't make sense.
The specified format driver would simply be ignored.

Make a set 'format' option an indication that a non-empty drive should
be created. This makes 'format' consistent with 'driver' and allows
using it with a block driver that doesn't need any other options (like
null-co/null-aio).

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
145f598e4a block: Introduce bs->explicit_options
bs->options doesn't only contain options that the user explicitly
requested, but also option that were derived from flags, the filename or
inherited from the parent node.

For reopen, it is important to know the difference because reopening the
parent can change inherited values in child nodes, but it shouldn't
change any options that were explicitly specified for the child.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
de3b53f007 block: Split out parse_json_protocol()
The next patch distinguishes options that were explicitly set and
options that were derived. bdrv_fill_option() added options of both
types: Options given by json: syntax should be counted as explicit, but
the rest is derived.

In preparation for the distinction, move json: parse to a separate
function.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:43 +01:00
Kevin Wolf
8e2160e2c7 block: Add infrastructure for option inheritance
Options are not actually inherited from the parent node yet, but this
commit lays the grounds for doing so.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:42 +01:00
Kevin Wolf
2851810223 block: reopen: Document option precedence and refactor accordingly
The interesting part of reopening an image is from which sources the
effective options should be taken, i.e. which options take precedence
over which other options. This patch documents the precedence that will
be implemented in the following patches.

It also refactors bdrv_reopen_queue(), so that the top-level reopened
node is handled the same way as children are. Option/flag inheritance
from the parent becomes just one item in the list and is done at the
beginning of the function, similar to how the other items are/will be
handled.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:42 +01:00
Kevin Wolf
4c9dfe5d8a block: Allow specifying child options in reopen
If the child was defined in the same context (-drive argument or
blockdev-add QMP command) as its parent, a reopen of the parent should
work the same and allow changing options of the child.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
2015-12-18 14:34:42 +01:00
Kevin Wolf
62392ebb09 block: Keep "driver" in bs->options
Instead of passing a separate drv argument to bdrv_open_common(), just
make sure that a "driver" option is set in the QDict. This also means
that a "driver" entry is consistently present in bs->options now.

This is another step towards keeping all options in the QDict (which is
the represenation of the blockdev-add QMP command).

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:42 +01:00
Kevin Wolf
4cdd01d32e block: Pass driver-specific options to .bdrv_refresh_filename()
In order to decide whether a blkdebug: filename can be produced or a
json: one is necessary, blkdebug checked whether bs->options had more
options than just "config", "x-image" or "image" (the latter including
nested options). That doesn't work well when generic block layer options
are present.

This patch passes an option QDict to the driver that contains only
driver-specific options, i.e. the options for the general block layer as
well as child nodes are already filtered out. Works much better this
way.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
2015-12-18 14:34:42 +01:00
Kevin Wolf
260fecf13b block: Exclude nested options only for children in append_open_options()
Some drivers have nested options (e.g. blkdebug rule arrays), which
don't belong to a child node and shouldn't be removed. Don't remove all
options with "." in their name, but check for the complete prefixes of
actually existing child nodes.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:42 +01:00
Kevin Wolf
9e700c1ac6 block: Consider all block layer options in append_open_options
The code already special-cased "node-name", which is currently the only
option passed in the QDict that isn't driver-specific. Generalise the
code to take all general block layer options into consideration.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
2015-12-18 14:34:42 +01:00
Kevin Wolf
d9b7b05703 block: Allow references for backing files
For bs->file, using references to existing BDSes has been possible for a
while already. This patch enables the same for bs->backing.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:42 +01:00
Kevin Wolf
40365552c2 mirror: Error out when a BDS would get two BBs
bdrv_replace_in_backing_chain() asserts that not both old and new
BlockDdriverState have a BlockBackend attached to them because both
would have to end up pointing to the new BDS and we don't support more
than one BB per BDS yet.

Before we can safely allow references to existing nodes as backing
files, we need to make sure that even if a backing file has a BB on it,
this doesn't crash qemu.

There are probably also some cases with the 'replaces' option set where
drive-mirror could fail this assertion today. They are fixed with this
error check as well.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2015-12-18 14:34:42 +01:00
Kevin Wolf
cddff5bae1 block: Fix reopen with semantically overlapping options
This fixes bdrv_reopen() calls like the following one:

    qemu-io -c 'open -o overlap-check.template=all /tmp/test.qcow2' \
    -c 'reopen -o overlap-check=none'

The approach taken so far would result in an options QDict that has both
"overlap-check.template=all" and "overlap-check=none", which obviously
conflicts. In this case, the old option should be overridden by the
newly specified option.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
2015-12-18 14:34:42 +01:00
Kevin Wolf
5365f44dfa qcow2: Add .bdrv_join_options callback
qcow2 accepts a few driver-specific options that overlap semantically
(e.g. "overlap-check" is an alias of "overlap-check.template", and any
missing cache size option is derived from the given ones).

When bdrv_reopen() merges the set of updated options with left out
options that should be kept at their old value, we need to consider this
and filter out any duplicates (which would generally cause errors
because new and old value would contradict each other).

This patch adds a .bdrv_join_options callback to BlockDriver and
implements it for qcow2.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
2015-12-18 14:34:42 +01:00
John Snow
35cea22373 iotests: 124: don't reopen qcow2
Don't create two interfaces to the same drive in the recently moved
failure test.

Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:42 +01:00
John Snow
ce2cbc4910 iotests: 124: move incremental failure test
Code motion only, in preparation for adjusting
the setUp procedure for this test.

Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:42 +01:00
John Snow
1b19bb9d17 iotests: 124: Split into two test classes
Split it into an abstract test class and an implementation class.

The split is primarily to facilitate more flexible setUp variations
for other kinds of tests without having to rewrite or shuffle around
all of these helpers.

See the following two patches for more of the "why."

Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-12-18 14:34:42 +01:00
Peter Maydell
67a7084062 Merge I/O channels base classes
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Merge remote-tracking branch 'remotes/berrange/tags/pull-io-channel-base-2015-12-18-1' into staging

Merge I/O channels base classes

# gpg: Signature made Fri 18 Dec 2015 12:18:38 GMT using RSA key ID 15104FDF
# gpg: Good signature from "Daniel P. Berrange <dan@berrange.com>"
# gpg:                 aka "Daniel P. Berrange <berrange@redhat.com>"

* remotes/berrange/tags/pull-io-channel-base-2015-12-18-1:
  io: add QIOChannelBuffer class
  io: add QIOChannelCommand class
  io: add QIOChannelWebsock class
  io: add QIOChannelTLS class
  io: add QIOChannelFile class
  io: add QIOChannelSocket class
  io: add QIOTask class for async operations
  io: add helper module for creating watches on FDs
  io: add abstract QIOChannel classes

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2015-12-18 12:42:10 +00:00
Daniel P. Berrange
d98e4eb7de io: add QIOChannelBuffer class
Add a QIOChannel subclass that is capable of performing I/O
to/from a memory buffer. This implementation does not attempt
to support concurrent readers & writers. It is designed for
serialized access where by a single thread at a time may write
data, seek and then read data back out.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18 12:18:31 +00:00
Daniel P. Berrange
195e14d026 io: add QIOChannelCommand class
Add a QIOChannel subclass that is capable of performing I/O
to/from a separate process, via a pair of pipes. The command
can be used for unidirectional or bi-directional I/O.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18 12:18:31 +00:00
Daniel P. Berrange
2d1d0e70cf io: add QIOChannelWebsock class
Add a QIOChannel subclass that can run the websocket protocol over
the top of another QIOChannel instance. This initial implementation
is only capable of acting as a websockets server. There is no support
for acting as a websockets client yet.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18 12:18:31 +00:00
Daniel P. Berrange
ed8ee42c40 io: add QIOChannelTLS class
Add a QIOChannel subclass that can run the TLS protocol over
the top of another QIOChannel instance. The object provides a
simplified API to perform the handshake when starting the TLS
session. The layering of TLS over the underlying channel does
not have to be setup immediately. It is possible to take an
existing QIOChannel that has done some handshake and then swap
in the QIOChannelTLS layer. This allows for use with protocols
which start TLS right away, and those which start plain text
and then negotiate TLS.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18 12:18:31 +00:00
Daniel P. Berrange
d6e48869a4 io: add QIOChannelFile class
Add a QIOChannel subclass that is capable of operating on things
that are files, such as plain files, pipes, character/block
devices, but notably not sockets.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18 12:18:31 +00:00
Daniel P. Berrange
559607ea17 io: add QIOChannelSocket class
Implement a QIOChannel subclass that supports sockets I/O.
The implementation is able to manage a single socket file
descriptor, whether a TCP/UNIX listener, TCP/UNIX connection,
or a UDP datagram. It provides APIs which can listen and
connect either asynchronously or synchronously. Since there
is no asynchronous DNS lookup API available, it uses the
QIOTask helper for spawning a background thread to ensure
non-blocking operation.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18 12:18:31 +00:00
Daniel P. Berrange
b02db2d920 io: add QIOTask class for async operations
A number of I/O operations need to be performed asynchronously
to avoid blocking the main loop. The caller of such APIs need
to provide a callback to be invoked on completion/error and
need access to the error, if any. The small QIOTask provides
a simple framework for dealing with such probes. The API
docs inline provide an outline of how this is to be used.

Some functions don't have the ability to run asynchronously
(eg getaddrinfo always blocks), so to facilitate their use,
the task class provides a mechanism to run a blocking
function in a thread, while triggering the completion
callback in the main event loop thread. This easily allows
any synchronous function to be made asynchronous, albeit
at the cost of spawning a thread.

In this series, the QIOTask class will be used for things like
the TLS handshake, the websockets handshake and TCP connect()
progress.

The concept of QIOTask is inspired by the GAsyncResult
interface / GTask class in the GIO libraries. The min
version requirements on glib don't allow those to be
used from QEMU, so QIOTask provides a facsimilie which
can be easily switched to GTask in the future if the
min version is increased.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18 12:18:30 +00:00
Daniel P. Berrange
1c809fa01d io: add helper module for creating watches on FDs
A number of the channel implementations will require the
ability to create watches on file descriptors / sockets.
To avoid duplicating this code in each channel, provide a
helper API for dealing with file descriptor watches.

There are two watch implementations provided. The first
is useful for bi-directional file descriptors such as
sockets, regular files, character devices, etc. The
second works with a pair of unidirectional file descriptors
such as pipes.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-12-18 12:18:05 +00:00