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  1. 06 6月, 2018 6 次提交
    • R
      util: virerror: Introduce virGetLastError{Code,Domain} public APIs · 50e96bb2
      由 ramyelkest 提交于 
      Many places in the code call virGetLastError() just to check the
raised error code, or domain. However virGetLastError() can return
NULL, so the code has to check for that first. This patch therefore
introduces virGetLasError{Code,Domain} functions which always return a
valid error code or domain respectively, thus dropping the need to
perform any checks on the error object.
Signed-off-by: NRamy Elkest <ramyelkest@gmail.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>
      50e96bb2
    • R
      util: Prefer virGetLastErrorMessage over direct err->message usage · 52d88d11
      由 ramyelkest 提交于 
      Signed-off-by: NRamy Elkest <ramyelkest@gmail.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>
      52d88d11
    • D
      qemu: remove pointless connect retry logic in agent · fc06debd
      由 Daniel P. Berrangé 提交于 
      When the agent code was first introduced back in

  commit c160ce33
  Author: Daniel P. Berrange <berrange@redhat.com>
  Date:   Wed Oct 5 18:31:54 2011 +0100

    QEMU guest agent support

there was code that would loop and retry the connection when opening
the agent socket. At this time, the only thing done in between the
opening of the monitor socket & opening of the agent socket was a
call to set the monitor capabilities. This was a no-op on non-QMP
versions, so in theory there could be a race which let us connect
to the monitor while the agent socket was still not created by QEMU.

In the modern world, however, we long ago mandated the use of QMP
for managing QEMU, so we're guaranteed to have a set capabilities
QMP call. Once we've seen a reply to this, we're guaranteed that
QEMU has fully initialized all backends and is in its event loop.

We can thus be sure the QEMU agent socket is present and don't need
to retry connections to it, even without having the chardev FD passing
feature.
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
      fc06debd
    • D
      qemu: don't retry connect() if doing FD passing · 7ef0471b
      由 Daniel P. Berrangé 提交于 
      Since libvirt called bind() and listen() on the UNIX socket, it is
guaranteed that connect() will immediately succeed, if QEMU is running
normally. It will only fail if QEMU has closed the monitor socket by
mistake or if QEMU has exited, letting the kernel close it.

With this in mind we can remove the retry loop and timeout when
connecting to the QEMU monitor if we are doing FD passing. Libvirt can
go straight to sending the QMP greeting and will simply block waiting
for a reply until QEMU is ready.
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
      7ef0471b
    • D
      qemu: support passing pre-opened UNIX socket listen FD · 30fb2276
      由 Daniel P. Berrangé 提交于 
      There is a race condition when spawning QEMU where libvirt has spawned
QEMU but the monitor socket is not yet open. Libvirt has to repeatedly
try to connect() to QEMU's monitor until eventually it succeeds, or
times out. We use kill() to check if QEMU is still alive so we avoid
waiting a long time if QEMU exited, but having a timeout at all is still
unpleasant.

With QEMU 2.12 we can pass in a pre-opened FD for UNIX domain or TCP
sockets. If libvirt has called bind() and listen() on this FD, then we
have a guarantee that libvirt can immediately call connect() and
succeed without any race.

Although we only really care about this for the monitor socket and agent
socket, this patch does FD passing for all UNIX socket based character
devices since there appears to be no downside to it.

We don't do FD passing for TCP sockets, however, because it is only
possible to pass a single FD, while some hostnames may require listening
on multiple FDs to cover IPv4 and IPv6 concurrently.
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
      30fb2276
    • D
      qemu: probe for -chardev 'fd' parameter for FD passing · 7cef131e
      由 Daniel P. Berrangé 提交于 
      QEMU >= 2.12 will support passing of pre-opened file descriptors for
socket based character devices.
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
      7cef131e
  3. 05 6月, 2018 34 次提交