Change the QEMU monitor file handle watch to poll for both
read & write events, as well as EOF. All I/O to/from the
QEMU monitor FD is now done in the event callback thread.
When the QEMU driver needs to send a command, it puts the
data to be sent into a qemuMonitorMessagePtr object instance,
queues it for dispatch, and then goes to sleep on a condition
variable. The event thread sends all the data, and then waits
for the reply to arrive, putting the response / error data
back into the qemuMonitorMessagePtr and notifying the condition
variable.
There is a temporary hack in the disk passphrase callback to
avoid acquiring the domain lock. This avoids a deadlock in
the command processing, since the domain lock is still held
when running monitor commands. The next commit will remove
the locking when running commands & thus allow re-introduction
of locking the disk passphrase callback
* src/qemu/qemu_driver.c: Temporarily don't acquire lock in
disk passphrase callback. To be reverted in next commit
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h: Remove
raw I/O functions, and a generic qemuMonitorSend() for
invoking a command
* src/qemu/qemu_monitor_text.c, src/qemu/qemu_monitor_text.h:
Remove all low level I/O, and use the new qemuMonitorSend()
API. Provide a qemuMonitorTextIOProcess() method for detecting
command/reply/prompt boundaries in the monitor data stream
Implementation of tunnelled migration, using a Unix Domain Socket
on the qemu backend. Note that this requires very new versions of
qemu (0.10.7 at least) in order to get the appropriate bugfixes.
Signed-off-by: Chris Lalancette <clalance@redhat.com>
* include/libvirt/libvirt.h.in: Public API contract for
virStreamPtr object
* src/libvirt_public.syms: Export data stream APIs
* src/libvirt_private.syms: Export internal helper APIs
* src/libvirt.c: Data stream API driver dispatch
* src/datatypes.h, src/datatypes.c: Internal helpers for virStreamPtr
object
* src/driver.h: Define internal driver API for streams
* .x-sc_avoid_write: Ignore src/libvirt.c because it trips
up on comments including write()
* python/Makefile.am: Add libvirt-override-virStream.py
* python/generator.py: Add rules for virStreamPtr class
* python/typewrappers.h, python/typewrappers.c: Wrapper
for virStreamPtr
* docs/libvirt-api.xml, docs/libvirt-refs.xml: Regenerate
with new APIs
Also add "make syntax-check" rules to ensure no new uses sneak in.
There are many uses of write like this:
if (write (fd, xml, towrite) != towrite)
return -1;
The problem is that the syscall can succeed, yet write less than
the requested number of bytes, so the caller should retry
rather than simply failing.
This patch changes most of them to use util.c's safewrite wrapper,
which encapsulates the process. Also, there were a few cases in
which the retry loop was open-coded, and I replaced those, too.
* Makefile.maint (sc_avoid_write): New rule, to avoid recurrence.
* .x-sc_avoid_write: New file. Record two legitimate exemptions.
* qemud/qemud.c (sig_handler, qemudClientWriteBuf): Use safewrite, not write.
* src/conf.c (__virConfWriteFile): Likewise.
* src/qemu_conf.c (qemudSaveConfig, qemudSaveNetworkConfig): Likewise.
* src/qemu_driver.c (qemudWaitForMonitor, qemudStartVMDaemon)
(qemudVMData, PROC_IP_FORWARD): Likewise.
* proxy/libvirt_proxy.c: Include "util.h".
(proxyWriteClientSocket): Use safewrite.
* src/test.c (testDomainSave, testDomainCoreDump): Likewise.
* src/proxy_internal.c (virProxyWriteClientSocket): Likewise.
* src/virsh.c: Include "util-lib.h".
(vshOutputLogFile): Use safewrite.
* src/console.c: Include "util-lib.h".
(vshRunConsole): Use safewrite.
Daniel P. Berrange