The LoopServer._create_device() duplicates the code from
`Loop.loop_for_fd()` right now. Given that this is relatively
subtle code it's better to not duplicate it and instead just
reuse the loop_for_fd() implementation in LoopServer.
LOOP_CONFIGURE allows to atomically configure the decive when opening
it. This avoid the possibility of a race condition where between set_fd
and set_status some operations are already accepted by the loopback
device. See https://lwn.net/Articles/820408/
This feature was included in the linux kernel 5.8 however it is safe to
not include any kind of fallback to the previous method as @obudai
points out that:
LOOP_CONFIGURE was backported into RHEL 8 kernel in RHEL 8.4 as a part
of https://bugzilla.redhat.com/show_bug.cgi?id=1881760 (block layer:
update to upstream v5.8).
Since RHEL 8.4 is currently the oldest supported release that we support
running osbuild on, it might be just fine implementing this without the
fallback.
From a centos stream 8 container:
kernel-4.18.0-448.el8.x86_64
- loop: Fix missing discard support when using LOOP_CONFIGURE (Ming Lei) [1997338]
- [block] loop: Set correct device size when using LOOP_CONFIGURE (Ming Lei) [1881760]
- [block] loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE (Ming Lei) [1881760]
- [block] loop: Add LOOP_CONFIGURE ioctl (Ming Lei) [1881760]
Now that jsoncomm is using a connection oriented protocol, the
`addr` parameter is not needed[*] and can thus be removed from
the `BaseAPI._message` message dispatcher. Adapt all usages
of it, including the tests.
[*] sendmsg ignores the destination parameter for connection
oriented sockets.
Make sure file descriptors are never leaked by closing them after
the `_message` method invocation. Clients that want to hold on to
fds past the scope of the method should use `FdSet.steal` to
extract those.
Adapt the `LoopServer`'s `_message` implementation accordingly.
Rely on the ability of `BaseAPI` to auto-generate socket addresses
when no one was provided. The `BuildRoot` does not rely on the
sockets being created in the `BuildRoot.api` directory anymore and
will instead bind-mount each individual socket address to the well
known location via the `BaseAPI.endpoint` identifier.
Convert all API providers to take the `socket_address` as an
optional keyword argument.
Add a new abstract class property to `BaseAPI` called `endpoint`,
meant to be implemented by deriving classes in order to identify
the end point name for the API provider.
Implement the new property in all existing API providers.
Close the event loop when the context is exited, which will clear
the internal queues and shut down the executor of the event loop.
Not doing this will create a warning when the object is garbage
collected.
Appart from giving us a hard time on s390x, this feature did not seem
to have a measurable effect. Moreover, O_DIRECT is not supported by
tmpfs so without this patch we could not use tmpfs as backing store,
which does speed up image generation considerably.
Drop the flag and and rather put the store on tmpfs in order to speed
things up.
This happens rarely when the same loop device is used in rapid
succession. The kernel flushes the page cache asynchronously, which
means that it might not be cleared yet when a new file is bound.
`set_status` checks if the cache is clear (`set_fd` doesn't).
Handle this by trying a different device when `set_status` returns
`EBUSY`.
Fixes#177
Don't wait until python's garbage collector closes the file descriptors
to loop devices. Close them when the `LoopServer` context manager exits,
after an assembler has finished running.
This might (hopefully) fix a race in destructing the asyncio.EventLoop
that's used in all API classes, which leads to warnings about unhandled
exceptions on CI.
This also puts their creation closer to where the client-side sockets
are created.
The socket that the osbuild and loop apis should talk on are passed into
their `__init__` function. The caller should be responsible for closing
those sockets.
This already happens in all current callers.
This fixes a non-fatal error on RHEL's python 3.6, because it was
calling `socket.close` on an already-closed socket:
Traceback (most recent call last):
File "/usr/lib64/python3.6/asyncio/base_events.py", line 529, in __del__
self.close()
File "/usr/lib64/python3.6/asyncio/unix_events.py", line 63, in close
super().close()
File "/usr/lib64/python3.6/asyncio/selector_events.py", line 99, in close
self._close_self_pipe()
File "/usr/lib64/python3.6/asyncio/selector_events.py", line 109, in _close_self_pipe
self._remove_reader(self._ssock.fileno())
File "/usr/lib64/python3.6/asyncio/selector_events.py", line 268, in _remove_reader
key = self._selector.get_key(fd)
File "/usr/lib64/python3.6/selectors.py", line 189, in get_key
return mapping[fileobj]
File "/usr/lib64/python3.6/selectors.py", line 70, in __getitem__
fd = self._selector._fileobj_lookup(fileobj)
File "/usr/lib64/python3.6/selectors.py", line 224, in _fileobj_lookup
return _fileobj_to_fd(fileobj)
File "/usr/lib64/python3.6/selectors.py", line 41, in _fileobj_to_fd
raise ValueError("Invalid file descriptor: {}".format(fd))
ValueError: Invalid file descriptor: -1
Expose the flags, address parameter of the underlying sock.sendmsg
method, in order to be able to explicitly specify the recipient of
the message; as needed in connection-less mode.
Python 3.2 renamed array.fromstring to array.frombytes, but kept
the former as an, now deprecated, alias. Use the canonical form
which indeed better describes what is going on.
If dir_fd wasn't passed, create_device() openend it to `/dev` and forgot
about closing it. To fix this, it would have to gain logic to only close
the fd if it wasn't passed in.
Side-step the problem by removing dir_fd, since nothing is using it
right now. We can add it back if something needs it.
Closing the socket is the responsibility of whoever opened it.
Fix this in the only user (qemu assembler) by using socket() in a `with`
block, which closes the socket on exit.
Import modules between files using the syntax `from . import foobar`,
renaming what used to be `FooBar` to `foobar.FooBar` when moved to a
separate file.
In __init__.py only import what is meant to be public API.
Signed-off-by: Tom Gundersen <teg@jklm.no>
loop.py is a simple wrapper around the kernel loop API. remoteloop.py
uses this to create a server/clinet pair that communicates over an
AF_UNIX/SOCK_DGRAM socket to allow the server to create loop devices
for the client.
The client passes a fd that should be bound to the resulting loop
device, and a dir-fd where the loop device node should be created.
The server returns the name of the device node to the client.
The idea is that the client is run from whithin a container without
access to devtmpfs (and hence /dev/loop-control), and the server
runs on the host. The client would typically pass its (fake) /dev
as the output directory.
For the client this will be similar to `losetup -f foo.img --show`.
[@larskarlitski: pylint: ignore the new LoopInfo class, because it
only has dynamic attributes. Also disable attribute-defined-outside-init,
which (among other problems) is not ignored for that class.]
Signed-off-by: Tom Gundersen <teg@jklm.no>
