This adds an implementation of virNetSocketGetUNIXIdentity()
using LOCAL_PEERCRED socket option and xucred struct, defined
in <sys/ucred.h> on systems that have it.
RHEL 6.3 uses dbus-devel-1.2.24, which lacked support for the
DBUS_TYPE_UNIX_FD define (contrast with Fedora 18 using 1.6.8).
But since it is an older dbus, it also lacks support for shutdown
inhibitions as provided by newer systemd.
Compilation failure introduced in commit 31330926.
* src/rpc/virnetserver.c (virNetServerAddShutdownInhibition):
Compile out if dbus is too old.
Use the freedesktop inhibition DBus service to prevent host
shutdown or session logout while any VMs are running.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently to deal with auto-shutdown libvirtd must periodically
poll all stateful drivers. Thus sucks because it requires
acquiring both the driver lock and locks on every single virtual
machine. Instead pass in a "inhibit" callback to virStateInitialize
which drivers can invoke whenever they want to inhibit shutdown
due to existance of active VMs.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
When seeing a message
virNetSASLContextCheckIdentity:146 : SASL client admin not allowed in whitelist
it isn't immediately obvious that 'admin' is the identity
being checked. Quote the string to make it more obvious
On OOM, xdr_destroy got called even though it wasn't created yet.
Found by coverity:
Error: UNINIT (CWE-457):
libvirt-0.10.2/src/rpc/virnetmessage.c:214: var_decl: Declaring
variable "xdr" without initializer.
libvirt-0.10.2/src/rpc/virnetmessage.c:219: cond_true: Condition
"virReallocN(&msg->buffer, 1UL /* sizeof (*msg->buffer) */,
msg->bufferLength) < 0", taking true branch
libvirt-0.10.2/src/rpc/virnetmessage.c:221: goto: Jumping to label
"cleanup"
libvirt-0.10.2/src/rpc/virnetmessage.c:257: label: Reached label
"cleanup"
libvirt-0.10.2/src/rpc/virnetmessage.c:258: uninit_use: Using
uninitialized value "xdr.x_ops".
The libvirt coding standard is to use 'function(...args...)'
instead of 'function (...args...)'. A non-trivial number of
places did not follow this rule and are fixed in this patch.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Commit 246143b fixed a warning on older gcc, but caused a warning
on newer gcc.
../../src/rpc/virnetserverservice.c: In function 'virNetServerServiceNewPostExecRestart':
../../src/rpc/virnetserverservice.c:277:41: error: pointer targets in passing argument 3 of 'virJSONValueObjectGetNumberUint' differ in signedness [-Werror=pointer-sign]
* src/rpc/virnetserverservice.c: Use correct types.
With older gcc and 64-bit size_t, the compiler issues a real warning:
rpc/virnetserverservice.c:277: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
Introduced in commit 0cc79255. Depending on machine endianness,
this warning represents a real bug that could mis-interpret the
value by a factor of 2^32. I don't know why I couldn't get newer
gcc to report the same warning message.
* src/rpc/virnetserverservice.c
(virNetServerServiceNewPostExecRestart): Use temporary instead.
Add two new APIs virNetServerNewPostExecRestart and
virNetServerPreExecRestart which allow a virNetServerPtr
object to be created from a JSON object and saved to a
JSON object, for the purpose of re-exec'ing a process.
This includes serialization of all registered services
and clients
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Add two new APIs virNetServerClientNewPostExecRestart and
virNetServerClientPreExecRestart which allow a virNetServerClientPtr
object to be created from a JSON object and saved to a
JSON object, for the purpose of re-exec'ing a process.
This includes serialization of the connected socket associated
with the client
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Add two new APIs virNetServerServiceNewPostExecRestart and
virNetServerServicePreExecRestart which allow a virNetServerServicePtr
object to be created from a JSON object and saved to a
JSON object, for the purpose of re-exec'ing a process.
This includes serialization of the listening sockets associated
with the service
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Add two new APIs virNetSocketNewPostExecRestart and
virNetSocketPreExecRestart which allow a virNetSocketPtr
object to be created from a JSON object and saved to a
JSON object, for the purpose of re-exec'ing a process.
As well as saving the state in JSON format, the second
method will disable the O_CLOEXEC flag so that the open
file descriptors are preserved across the process re-exec()
Since it is not possible to serialize SASL or TLS encryption
state, an error will be raised if attempting to perform
serialization on non-raw sockets
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Continue consolidation of process functions by moving some
helpers out of command.{c,h} into virprocess.{c,h}
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.
* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/; If/. If/
Relatively straightforward. Our decision to make block job
speed a long keeps haunting us on new API.
* src/remote/remote_protocol.x (remote_domain_block_commit_args):
New struct.
* src/remote/remote_driver.c (remote_driver): Enable it.
* src/remote_protocol-structs: Regenerate.
* src/rpc/gendispatch.pl (long_legacy): Exempt another bandwidth.
* src/rpc/gendispatch.pl: (virNodeSetMemoryParameters is the
the special one which needs a connection object as the first
argument, improve the generator to support it).
* daemon/remote.c: (Implement the server side handler for
virDomainGetMemoryParameters)
* src/remote/remote_driver.c: (Implement the client side handler
for virDomainGetMemoryParameters)
* src/remote/remote_protocol.x: (New RPC procedures for the two
new APIs and structs to represent the args and ret for it)
* src/remote_protocol-structs: Likewise
Fix for CVE-2012-4423.
When generating RPC protocol messages, it's strictly needed to have a
continuous line of numbers or RPC messages. However in case anyone
tries backporting some functionality and will skip a number, there is
a possibility to make the daemon segfault with newer virsh (version of
the library, rpc call, etc.) even unintentionally.
The problem is that the skipped numbers will get func filled with
NULLs, but there is no check whether these are set before the daemon
tries to run them. This patch very simply enhances one check and fixes
that.
I got an off-list report about a bad diagnostic:
Target network card mac 52:54:00:49:07:ccdoes not match source 52:54:00:49:07:b8
True to form, I've added a syntax check rule to prevent it
from recurring, and found several other offenders.
* cfg.mk (sc_require_whitespace_in_translation): New rule.
* src/conf/domain_conf.c (virDomainNetDefCheckABIStability): Add
space.
* src/esx/esx_util.c (esxUtil_ParseUri): Likewise.
* src/qemu/qemu_command.c (qemuCollectPCIAddress): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSetMetadata)
(qemuDomainGetMetadata): Likewise.
* src/qemu/qemu_hotplug.c (qemuDomainChangeNetBridge): Likewise.
* src/rpc/virnettlscontext.c
(virNetTLSContextCheckCertDNWhitelist): Likewise.
* src/vmware/vmware_driver.c (vmwareDomainResume): Likewise.
* src/vbox/vbox_tmpl.c (vboxDomainGetXMLDesc, vboxAttachDrives):
Avoid false negatives.
* tools/virsh-domain.c (info_save_image_dumpxml): Reword.
Based on a report by Luwen Su.
e5a1bee07 introduced a regression in Boxes: when Boxes is left idle
(it's still doing some libvirt calls in the background), the
libvirt connection gets closed after a few minutes. What happens is
that this code in virNetClientIOHandleOutput gets triggered:
if (!thecall)
return -1; /* Shouldn't happen, but you never know... */
and after the changes in e5a1bee07, this causes the libvirt connection
to be closed.
Upon further investigation, what happens is that
virNetClientIOHandleOutput is called from gvir_event_handle_dispatch
in libvirt-glib, which is triggered because the client fd became
writable. However, between the times gvir_event_handle_dispatch
is called, and the time the client lock is grabbed and
virNetClientIOHandleOutput is called, another thread runs and
completes the current call. 'thecall' is then NULL when the first
thread gets to run virNetClientIOHandleOutput.
After describing this situation on IRC, danpb suggested this:
11:37 < danpb> In that case I think the correct thing would be to change
'return -1' above to 'return 0' since that's not actually an
error - its a rare, but expected event
which is what this patch is doing. I've tested it against master
libvirt, and I didn't get disconnected in ~10 minutes while this
happens in less than 5 minutes without this patch.
Unfortunately libssh2 doesn't support all types of host keys that can be
saved in the known_hosts file. Also it does not report that parsing of
the file failed. This results into truncated known_hosts files where the
standard client stores keys also in other formats (eg.
ecdsa-sha2-nistp256).
This patch changes the default location of the known_hosts file into the
libvirt private configuration directory, where it will be only written
by the libssh2 layer itself. This prevents trashing user's known_host
file.
The libssh2 code wasn't supposed to create the known_hosts file, but
recent findings show, that we can't use the default created by OpenSSH
as libssh2 might damage it. We need to create a private known_hosts file
in the config path.
This patch adds support for skipping error if the known_hosts file is
not present and let libssh2 create a new one.
This patch adds a glue layer to enable using libssh2 code with the
network client code.
As in the original client implementation, shell code is sent to the
server to detect correct options for netcat and connect to libvirt's
unix socket.
This patch enables virNetSocket to be used as an ssh client when
properly configured.
This patch adds function virNetSocketNewConnectLibSSH2() that takes all
needed parameters and creates a libssh2 session and performs steps
needed to open the connection and then create a virNetSocket that
seamlesly encapsulates the communication.
This patch adds helper functions that enable us to use libssh2 in
conjunction with libvirt's virNetSockets for ssh transport instead of
spawning "ssh" client process.
This implemetation supports tunneled plaintext, keyboard-interactive,
private key, ssh agent based and null authentication. Libvirt's Auth
callback is used for interaction with the user. (Keyboard interactive
authentication, adding of host keys, private key passphrases). This
enables seamless integration into the application using libvirt. No
helpers as "ssh-askpass" are needed.
Reading and writing of OpenSSH style "known_hosts" files is supported.
Communication is done using SSH exec channel, where the user may specify
arbitrary command to be executed on the remote side and reads and writes
to/from stdin/out are sent through the ssh channel. Usage of stderr is
not (yet) supported.
In order to support systemd socket based activation, it needs to
be possible to create virNetSocketPtr and virNetServerServicePtr
instance from a pre-opened file descriptor
In preparation for adding further constructors, refactor
the virNetServerClientNew method to move most of the code
into a common virNetServerClientNewInternal helper API.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently the virNetServerDispatchNewClient both creates the
virNetServerClientPtr instance and registers it with the
virNetServerPtr internal state. Split the client registration
code out into a separate virNetServerAddClient method to
allow future reuse from other contexts
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently there is a hook function that is invoked when a
new client connection comes in, which allows an app to
setup private data. This setup will make it difficult to
serialize client state during process re-exec(). Change to
a model where the app registers a callback when creating
the virNetServerPtr instance, which is used to allocate
the client private data immediately during virNetClientPtr
construction.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently the virNetClientPtr constructor will always register
the async IO event handler and the keepalive objects. In the
case of the lock manager, there will be no event loop available
nor keepalive support required. Split this setup out of the
constructor and into separate methods.
The remote driver will enable async IO and keepalives, while
the LXC driver will only enable async IO
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently the virNetServerServicePtr is responsible for
creating the virNetServerClientPtr instance when accepting
a new connection. Change this so that the virNetServerServicePtr
merely gives virNetServerPtr a virNetSocketPtr instance. The
virNetServerPtr can then create the virNetServerClientPtr
as it desires
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
From man poll(2), poll does not set errno=EAGAIN on interrupt, however
it does set errno=EINTR. Have libvirt retry on the appropriate errno.
Under heavy load, a program of mine kept getting libvirt errors 'poll on
socket failed: Interrupted system call'. The signals were SIGCHLD from
processes forked by threads unrelated to those using libvirt.
Commit 1f6f723 missed a step. At first I was worried that scrubbing
the conditionals would lead to a runtime failure when compiled without
avahi, but my testing makes it appear that the runtime error will only
occur if the .conf files in /etc request mdns advertisement; and the
old behavior was to silently ignore the request, so this is actually
a better behavior of only failing when the config requests the
impossible.
* src/rpc/virnetserver.c: Drop HAVE_AVAHI conditionals; all
callers already passed NULL if mdns_adv was not configured.
The recent changes to the testsuite to validate exported symbols
flushed out a case of unconditionally exporting symbols that
were only conditionally compiled under HAVE_AVAHI.
* src/Makefile.am (libvirt_net_rpc_server_la_SOURCES): Compile
virnetservermdns unconditionally.
* configure.ac (HAVE_AVAHI): Drop unused automake conditional.
* src/rpc/virnetservermdns.c: Add fallbacks when Avahi is not
present.
The cfg.mk file rule to check for tab characters was not
applied to perl files. Much of our Perl code is full of
tabs as a result. Kill them, kill them all !
Update the gendispatch.pl script to get a little closer to
being able to generate code for the LXC monitor, by passing
in the struct prefix separately from the procedure prefix.
Also allow method names using virCapitalLetters instead
of vir_underscore_separator
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
In the socket event handler for the RPC client we must deal
with read/write events, before checking for EOF, otherwise
we might close the socket before we've read & acted upon the
last RPC messages
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Allow detection of socket close in virNetClient via a callback
function, triggered on any condition that causes the socket to
be closed.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently if the keepalive timer triggers, the 'markClose'
flag is set on the virNetClient. A controlled shutdown will
then be performed. If an I/O error occurs during read or
write of the connection an error is raised back to the
caller, but the connection isn't marked for close. This
patch ensures that all I/O error scenarios always result
in the connection being marked for close.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Any time we have a string with no % passed through gettext, a
translator can inject a % to cause a stack overread. When there
is nothing to format, it's easier to ask for a string that cannot
be used as a formatter, by using a trivial "%s" format instead.
In the past, we have used --disable-nls to catch some of the
offenders, but that doesn't get run very often, and many more
uses have crept in. Syntax check to the rescue!
The syntax check can catch uses such as
virReportError(code,
_("split "
"string"));
by using a sed script to fold context lines into one pattern
space before checking for a string without %.
This patch is just mechanical insertion of %s; there are probably
several messages touched by this patch where we would be better
off giving the user more information than a fixed string.
* cfg.mk (sc_prohibit_diagnostic_without_format): New rule.
* src/datatypes.c (virUnrefConnect, virGetDomain)
(virUnrefDomain, virGetNetwork, virUnrefNetwork, virGetInterface)
(virUnrefInterface, virGetStoragePool, virUnrefStoragePool)
(virGetStorageVol, virUnrefStorageVol, virGetNodeDevice)
(virGetSecret, virUnrefSecret, virGetNWFilter, virUnrefNWFilter)
(virGetDomainSnapshot, virUnrefDomainSnapshot): Add %s wrapper.
* src/lxc/lxc_driver.c (lxcDomainSetBlkioParameters)
(lxcDomainGetBlkioParameters): Likewise.
* src/conf/domain_conf.c (virSecurityDeviceLabelDefParseXML)
(virDomainDiskDefParseXML, virDomainGraphicsDefParseXML):
Likewise.
* src/conf/network_conf.c (virNetworkDNSHostsDefParseXML)
(virNetworkDefParseXML): Likewise.
* src/conf/nwfilter_conf.c (virNWFilterIsValidChainName):
Likewise.
* src/conf/nwfilter_params.c (virNWFilterVarValueCreateSimple)
(virNWFilterVarAccessParse): Likewise.
* src/libvirt.c (virDomainSave, virDomainSaveFlags)
(virDomainRestore, virDomainRestoreFlags)
(virDomainSaveImageGetXMLDesc, virDomainSaveImageDefineXML)
(virDomainCoreDump, virDomainGetXMLDesc)
(virDomainMigrateVersion1, virDomainMigrateVersion2)
(virDomainMigrateVersion3, virDomainMigrate, virDomainMigrate2)
(virStreamSendAll, virStreamRecvAll)
(virDomainSnapshotGetXMLDesc): Likewise.
* src/nwfilter/nwfilter_dhcpsnoop.c (virNWFilterSnoopReqLeaseDel)
(virNWFilterDHCPSnoopReq): Likewise.
* src/openvz/openvz_driver.c (openvzUpdateDevice): Likewise.
* src/openvz/openvz_util.c (openvzKBPerPages): Likewise.
* src/qemu/qemu_cgroup.c (qemuSetupCgroup): Likewise.
* src/qemu/qemu_command.c (qemuBuildHubDevStr, qemuBuildChrChardevStr)
(qemuBuildCommandLine): Likewise.
* src/qemu/qemu_driver.c (qemuDomainGetPercpuStats): Likewise.
* src/qemu/qemu_hotplug.c (qemuDomainAttachNetDevice): Likewise.
* src/rpc/virnetsaslcontext.c (virNetSASLSessionGetIdentity):
Likewise.
* src/rpc/virnetsocket.c (virNetSocketNewConnectUNIX)
(virNetSocketSendFD, virNetSocketRecvFD): Likewise.
* src/storage/storage_backend_disk.c
(virStorageBackendDiskBuildPool): Likewise.
* src/storage/storage_backend_fs.c
(virStorageBackendFileSystemProbe)
(virStorageBackendFileSystemBuild): Likewise.
* src/storage/storage_backend_rbd.c
(virStorageBackendRBDOpenRADOSConn): Likewise.
* src/storage/storage_driver.c (storageVolumeResize): Likewise.
* src/test/test_driver.c (testInterfaceChangeBegin)
(testInterfaceChangeCommit, testInterfaceChangeRollback):
Likewise.
* src/vbox/vbox_tmpl.c (vboxListAllDomains): Likewise.
* src/xenxs/xen_sxpr.c (xenFormatSxprDisk, xenFormatSxpr):
Likewise.
* src/xenxs/xen_xm.c (xenXMConfigGetUUID, xenFormatXMDisk)
(xenFormatXM): Likewise.
Per the FSF address could be changed from time to time, and GNU
recommends the following now: (http://www.gnu.org/licenses/gpl-howto.html)
You should have received a copy of the GNU General Public License
along with Foobar. If not, see <http://www.gnu.org/licenses/>.
This patch removes the explicit FSF address, and uses above instead
(of course, with inserting 'Lesser' before 'General').
Except a bunch of files for security driver, all others are changed
automatically, the copyright for securify files are not complete,
that's why to do it manually:
src/security/security_selinux.h
src/security/security_driver.h
src/security/security_selinux.c
src/security/security_apparmor.h
src/security/security_apparmor.c
src/security/security_driver.c
Update the libvirtd dispatch code to use virReportError
instead of the virNetError custom macro
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
To allow virNetServerRun/virNetServerQuit to be invoked multiple
times, we must reset the 'quit' flag in virNetServerRun
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
In the delayed close mode, we're just waiting for final data to
be written back to the client. While waiting, we should not
bother to read more data from the client.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Instead of only removing the ending newline character, it is
better to remove all of standard whitespace character for the
sake of log format.
One example that we have to do this is:
After three times incorrect password input, virsh command
virsh -c qemu://remoteserver/system will report error like:
: Connection reset by peerey,gssapi-keyex,gssapi-with-mic,password).
But it should be:
Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
: Connection reset by peer
The reason is that we dropped the newline, but have a '\r' left.
The terminal interprets it as "move the cursor back to the start
of the current line", so the error string is messed up.
The virNetServerMDNSTimeoutNew method was casting a long long
to an int when reporting errors. This should just be using
%lld instead of %d, avoiding the need to cast
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Commit 32a9aac switched libvirt to use the XDG base directories
to locate most of its data/config. In particular, the per-user socket
for qemu:///session is now stored in the XDG runtime directory.
This directory is located by looking at the XDG_RUNTIME_DIR environment
variable, with a fallback to ~/.cache/libvirt if this variable is not
set.
When the daemon is autospawned because a client application wants
to use qemu:///session, the daemon is ran in a clean environment
which does not contain XDG_RUNTIME_DIR. It will create its socket
in ~/.cache/libvirt. If the client application has XDG_RUNTIME_DIR
set, it will not look for the socket in the fallback place, and will
fail to connect to the autospawned daemon.
This patch adds XDG_RUNTIME_DIR to the daemon environment before
auto-starting it. I've done this in virNetSocketForkDaemon rather
than in virCommandAddEnvPassCommon as I wasn't sure we want to pass
these variables to other commands libvirt spawns. XDG_CACHE_HOME
and XDG_CONFIG_HOME are also added to the daemon env as it makes use
of those as well.
Refactor the RPC server dispatcher code so that if 'max_workers==0'
the entire server will run single threaded. This is useful for
use cases where there will only ever be 1 client connected
which serializes its requests
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The callback that is invoked when a new RPC client is
initialized does not have any opaque parameter. Add
one so that custom data can be passed into the callback
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The test of ref count is not protected by lock, which is unsafe because
the ref count may have been changed by other threads during the test.
This patch fixes this.
When shutting down libvirtd, the virNetServer shutdown can deadlock
if there are in-flight jobs being handled by virNetServerHandleJob().
virNetServerFree() will acquire the virNetServer lock and call
virThreadPoolFree() to terminate the workers, waiting for the workers
to finish. But in-flight workers will attempt to acquire the
virNetServer lock, resulting in deadlock.
Fix the deadlock by unlocking the virNetServer lock before calling
virThreadPoolFree(). This is safe since the virNetServerPtr object
is ref-counted and only decrementing the ref count needs to be
protected. Additionally, there is no need to re-acquire the lock
after virThreadPoolFree() completes as all the workers have
terminated.
First 'poll' can't return EWOULDBLOCK, and second, we're checking errno
so far away from the poll() call that we've probably already trashed the
original errno value.
In addition to keepalive responses, we also need to send keepalive
requests from client IO loop to properly detect dead connection in case
a libvirt API is called from the main loop, which prevents any timers to
be called.
The previous commit removed the only usage of ``all'' parameter in
virKeepAliveStopInternal, which was actually the only reason for having
virKeepAliveStopInternal. This effectively reverts most of commit
6446a9e20c.
When a libvirt API is called from the main event loop (which seems to be
common in event-based glib apps), the client IO loop would properly
handle keepalive requests sent by a server but will not actually send
them because the main event loop is blocked with the API. This patch
gets rid of response timer and the thread which is processing keepalive
requests is also responsible for queueing responses for delivery.
Add virKeepAliveTimeout and virKeepAliveTrigger APIs that can be used to
set poll timeouts and trigger keepalive timer. virKeepAliveTrigger
checks if it is called to early and does nothing in that case.
The code that needs to be run every keepalive interval of inactivity was
only called from a timer and thus from the main event loop. We will need
to call the code directly from another place.
As non-blocking calls are no longer dropped, we don't really need to
care that much about their fate and wait for the thread with the buck
to process them. If another thread has the buck, we can just push a
non-blocking call to the queue and be done with it.
So far, we were dropping non-blocking calls whenever sending them would
block. In case a client is sending lots of stream calls (which are not
supposed to generate any reply), the assumption that having other calls
in a queue is sufficient to get a reply from the server doesn't work. I
tried to fix this in b1e374a7ac but
failed and reverted that commit.
With this patch, non-blocking calls are never dropped (unless the
connection is being closed) and will always be sent.
Normally, when every call has a thread associated with it, the thread
may get the buck and be in charge of sending all calls until its own
call is done. When we introduced non-blocking calls, we had to add
special handling of new non-blocking calls. This patch uses event loop
to send data if there is no thread to get the buck so that any
non-blocking calls left in the queue are properly sent without having to
handle them specially. It also avoids adding even more cruft to client
IO loop in the following patches.
With this change in, non-blocking calls may see unpredictable delays in
delivery when the client has no event loop registered. However, the only
non-blocking calls we have are keepalives and we already require event
loop for them, which makes this a non-issue until someone introduces new
non-blocking calls.
My latest patch for RPC rework (a2c304f687) introduced a memory leak.
virNetMessageEncodeHeader() is calling VIR_ALLOC_N(msg->buffer, ...)
despite fact, that msg->buffer isn't VIR_FREE()'d on all paths calling
the function. Therefore, rather than injecting free statement switch to
VIR_REALLOC_N().
Since we are allocating RPC buffer dynamically, we can increase limits
for max. size of RPC message and RPC string. This is needed to cover
some corner cases where libvirt is run on such huge machines that their
capabilities XML is 4 times bigger than our current limit. This leaves
users with inability to even connect.
Currently, we are allocating buffer for RPC messages statically.
This is not such pain when RPC limits are small. However, if we want
ever to increase those limits, we need to allocate buffer dynamically,
based on RPC message len (= the first 4 bytes). Therefore we will
decrease our mem usage in most cases and still be flexible enough in
corner cases.
Remove the uid param from virGetUserConfigDirectory,
virGetUserCacheDirectory, virGetUserRuntimeDirectory,
and virGetUserDirectory
These functions were universally called with the
results of getuid() or geteuid(). To make it practical
to port to Win32, remove the uid parameter and hardcode
geteuid()
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
When you try to connect to a socket in the abstract namespace,
the error will be ECONNREFUSED for a non-listening daemon. With
the non-abstract namespace though, you instead get ENOENT. Add
a check for this extra errno when auto-spawning the daemon
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This reverts commit b1e374a7ac, which was
rather bad since I failed to consider all sides of the issue. The main
things I didn't consider properly are:
- a thread which sends a non-blocking call waits for the thread with
the buck to process the call
- the code doesn't expect non-blocking calls to remain in the queue
unless they were already partially sent
Thus, the reverted patch actually breaks more than what it fixes and
clients (which may even be libvirtd during p2p migrations) will likely
end up in a deadlock.
Currently, non-blocking calls are either sent immediately or discarded
in case sending would block. This was implemented based on the
assumption that the non-blocking keepalive call is not needed as there
are other calls in the queue which would keep the connection alive.
However, if those calls are no-reply calls (such as those carrying
stream data), the remote party knows the connection is alive but since
we don't get any reply from it, we think the connection is dead.
This is most visible in tunnelled migration. If it happens to be longer
than keepalive timeout (30s by default), it may be unexpectedly aborted
because the connection is considered to be dead.
With this patch, we only discard non-blocking calls when the last call
with a thread is completed and thus there is no thread left to keep
sending the remaining non-blocking calls.
The docs for virConnectSetKeepAlive() advertise that this function
should be able to disable keepalives on negative or zero interval time.
This patch removes the check that prohibited this and adds code to
disable keepalives on negative/zero interval.
* src/libvirt.c: virConnectSetKeepAlive(): - remove check for negative
values
* src/rpc/virnetclient.c
* src/rpc/virnetclient.h: - add virNetClientKeepAliveStop() to disable
keepalive messages
* src/remote/remote_driver.c: remoteSetKeepAlive(): -add ability to
disable keepalives
POSIX says that sa_sigaction is only safe to use if sa_flags
includes SA_SIGINFO; conversely, sa_handler is only safe to
use when flags excludes that bit. Gnulib doesn't guarantee
an implementation of SA_SIGINFO, but does guarantee that
if SA_SIGINFO is undefined, we can safely define it to 0 as
long as we don't dereference the 2nd or 3rd argument of
any handler otherwise registered via sa_sigaction.
Based on a report by Wen Congyang.
* src/rpc/virnetserver.c (SA_SIGINFO): Stub for mingw.
(virNetServerSignalHandler): Avoid bogus dereference.
(virNetServerFatalSignal, virNetServerNew): Set flags properly.
(virNetServerAddSignalHandler): Drop unneeded #ifdef.
DBus connection. The HAL device code further requires that
the DBus connection is integrated with the event loop and
provides such glue logic itself.
The forthcoming FirewallD integration also requires a
dbus connection with event loop integration. Thus we need
to pull the current event loop glue out of the HAL driver.
Thus we create src/util/virdbus.{c,h} files. This contains
just one method virDBusGetSystemBus() which obtains a handle
to the single shared system bus instance, with event glue
automagically setup.
The code is splattered with a mix of
sizeof foo
sizeof (foo)
sizeof(foo)
Standardize on sizeof(foo) and add a syntax check rule to
enforce it
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Commit 5d4b0c4c80 tried to fix certain classes of VPATH builds,
but was too limited. In particular, Guannan Ren reported:
> For example: The libvirt source code resides in /home/testuser,
> I make dist in /tmp/buildvpath, the XDR routine .c file will
> include full path of the header file like:
>
> #include "/home/testuser/src/rpc/virnetprotocol.h"
> #include "internal.h"
> #include <arpa/inet.h>
>
> If we distribute the tarball to another machine to compile,
> it will report error as follows:
>
> rpc/virnetprotocol.c:7:59: fatal error:
> /home/testuser/src/rpc/virnetprotocol.h: No such file or directory
* src/rpc/genprotocol.pl: Fix more include lines.
On 64-bit platforms, unsigned long and unsigned long long are
identical, so we don't have to worry about overflow checks.
On 32-bit platforms, anywhere we narrow unsigned long long back
to unsigned long, we have to worry about overflow; it's easier
to do this in one place by having most of the code use the same
or wider types, and only doing the narrowing at the last minute.
Therefore, the memory set commands remain unsigned long, and
the memory get command now centralizes the overflow check into
libvirt.c, so that drivers don't have to repeat the work.
This also fixes a bug where xen returned the wrong value on
failure (most APIs return -1 on failure, but getMaxMemory
must return 0 on failure).
* src/driver.h (virDrvDomainGetMaxMemory): Use long long.
* src/libvirt.c (virDomainGetMaxMemory): Raise overflow.
* src/test/test_driver.c (testGetMaxMemory): Fix driver.
* src/rpc/gendispatch.pl (name_to_ProcName): Likewise.
* src/xen/xen_hypervisor.c (xenHypervisorGetMaxMemory): Likewise.
* src/xen/xen_driver.c (xenUnifiedDomainGetMaxMemory): Likewise.
* src/xen/xend_internal.c (xenDaemonDomainGetMaxMemory):
Likewise.
* src/xen/xend_internal.h (xenDaemonDomainGetMaxMemory):
Likewise.
* src/xen/xm_internal.c (xenXMDomainGetMaxMemory): Likewise.
* src/xen/xm_internal.h (xenXMDomainGetMaxMemory): Likewise.
* src/xen/xs_internal.c (xenStoreDomainGetMaxMemory): Likewise.
* src/xen/xs_internal.h (xenStoreDomainGetMaxMemory): Likewise.
* src/xenapi/xenapi_driver.c (xenapiDomainGetMaxMemory):
Likewise.
* src/esx/esx_driver.c (esxDomainGetMaxMemory): Likewise.
* src/libxl/libxl_driver.c (libxlDomainGetMaxMemory): Likewise.
* src/qemu/qemu_driver.c (qemudDomainGetMaxMemory): Likewise.
* src/lxc/lxc_driver.c (lxcDomainGetMaxMemory): Likewise.
* src/uml/uml_driver.c (umlDomainGetMaxMemory): Likewise.
A multi-threaded client with event loop may crash if one of its threads
closes a connection while event loop is in the middle of sending
keep-alive message (either request or response). The right place for it
is inside virNetClientIOEventLoop() between poll() and
virNetClientLock(). We should only close a connection directly if no-one
is using it and defer the closing to the last user otherwise. So far we
only did so if the close was initiated by keep-alive timeout.
Nuke the last vestiges of printing pid_t values with the wrong
types, at least in code compiled on mingw64. There may be other
places, but for now they are only compiled on systems where the
existing %d doesn't trigger gcc warnings.
* src/rpc/virnetsocket.c (virNetSocketNew): Use %lld and casting,
rather than assuming any particular int type for pid_t.
* src/util/command.c (virCommandRunAsync, virPidWait)
(virPidAbort): Likewise.
(verify): Drop a now stale assertion.
Our HACKING discourages use of malloc and free, for at least
a couple of years now. But we weren't enforcing it, until now :)
For now, I've exempted python and tests, and will clean those up
in subsequent patches. Examples should be permanently exempt,
since anyone copying our examples won't have use of our
internal-only memory.h via libvirt_util.la.
* cfg.mk (sc_prohibit_raw_allocation): New rule.
(exclude_file_name_regexp--sc_prohibit_raw_allocation): and
exemptions.
* src/cpu/cpu.c (cpuDataFree): Avoid false positive.
* src/conf/network_conf.c (virNetworkDNSSrvDefParseXML): Fix
offenders.
* src/libxl/libxl_conf.c (libxlMakeDomBuildInfo, libxlMakeVfb)
(libxlMakeDeviceModelInfo): Likewise.
* src/rpc/virnetmessage.c (virNetMessageSaveError): Likewise.
* tools/virsh.c (_vshMalloc, _vshCalloc): Likewise.
Qemu is adding the ability to do a partial rebase. That is, given:
base <- intermediate <- current
virDomainBlockPull will produce:
current
but qemu now has the ability to leave base in the chain, to produce:
base <- current
Note that current qemu can only do a forward merge, and only with
the current image as the destination, which is fully described by
this API without flags. But in the future, it may be possible to
enhance this API for additional scenarios by using flags:
Merging the current image back into a previous image (that is,
undoing a live snapshot), could be done by passing base as the
destination and flags with a bit requesting a backward merge.
Merging any other part of the image chain, whether forwards (the
backing image contents are pulled into the newer file) or backwards
(the deltas recorded in the newer file are merged back into the
backing file), could also be done by passing a new flag that says
that base should be treated as an XML snippet rather than an
absolute path name, where the XML could then supply the additional
instructions of which part of the image chain is being merged into
any other part.
* include/libvirt/libvirt.h.in (virDomainBlockRebase): New
declaration.
* src/libvirt.c (virDomainBlockRebase): Implement it.
* src/libvirt_public.syms (LIBVIRT_0.9.10): Export it.
* src/driver.h (virDrvDomainBlockRebase): New driver callback.
* src/rpc/gendispatch.pl (long_legacy): Add exemption.
* docs/apibuild.py (long_legacy_functions): Likewise.
This API allows a domain to be put into one of S# ACPI states.
Currently, S3 and S4 are supported. These states are shared
with virNodeSuspendForDuration.
However, for now we don't support any duration other than zero.
The same apply for flags.
The RPC generator transforms methods matching certain
patterns like 'id' or 'uuid', etc but does not anchor
its matches to the end of the word. So if a method
contains 'id' in the middle (eg virIdentity) then the
RPC generator munges that.
* src/rpc/gendispatch.pl: Anchor matches
To avoid a namespace clash with forthcoming identity APIs,
rename the virNet*GetLocalIdentity() APIs to have the form
virNet*GetUNIXIdentity()
* daemon/remote.c, src/libvirt_private.syms: Update
for renamed APIs
* src/rpc/virnetserverclient.c, src/rpc/virnetserverclient.h,
src/rpc/virnetsocket.c, src/rpc/virnetsocket.h: s/LocalIdentity/UNIXIdentity/
If client stream does not have any data to sink and neither received
EOF, a dummy packet is sent to the daemon signalising client is ready to
sink some data. However, after we added event loop to client a race may
occur:
Thread 1 calls virNetClientStreamRecvPacket and since no data are cached
nor stream has EOF, it decides to send dummy packet to server which will
sent some data in turn. However, during this decision and actual message
exchange with server -
Thread 2 receives last stream data from server. Therefore an EOF is set
on stream and if there is a call waiting (which is not yet) it is woken
up. However, Thread 1 haven't sent anything so far, so there is no call
to be woken up. So this thread sent dummy packet to daemon, which
ignores that as no stream is associated with such packet and therefore
no reply will ever come.
This race causes client to hang indefinitely.
The RPC code had several latent memory leaks and an attempt to
free the wrong string, but thankfully nothing triggered them
(blkiotune was the only one returning a string, and always as
the last parameter). Also, our cleanups for rpcgen ended up
nuking a line of code that renders VIR_TYPED_PARAM_INT broken,
because it was the only use of 'i' in a function, even though
it was a member usage rather than a standalone declaration.
* daemon/remote.c (remoteSerializeTypedParameters): Free the
correct array element.
(remoteDispatchDomainGetSchedulerParameters)
(remoteDispatchDomainGetSchedulerParametersFlags)
(remoteDispatchDomainBlockStatsFlags)
(remoteDispatchDomainGetMemoryParameters): Don't leak strings.
* src/rpc/genprotocol.pl: Don't nuke member-usage of 'buf' or 'i'.
When one thread passes the buck to another thread, it uses
virCondSignal to wake up the target thread. The variable
'haveTheBuck' is not updated in a race-free manner when
this occurs. The current thread sets it to false, and the
woken up thread sets it to true. There is a window where
a 3rd thread can come in and grab the buck.
Even if this didn't lead to crashes & deadlocks, this would
still result in unfairness in the buckpassing algorithm.
A better solution is to *never* set haveTheBuck to false
when we're passing the buck. Only set it to false when there
is no further thread waiting for the buck.
* src/rpc/virnetclient.c: Only set haveTheBuck to false
if no thread is waiting
Commit fd06692544 tried to fix
a race condition in
commit fa9595003d
Author: Daniel P. Berrange <berrange@redhat.com>
Date: Fri Nov 11 15:28:41 2011 +0000
Explicitly track whether the buck is held in remote client
Unfortunately there is a second race condition whereby the
event loop can trigger due to incoming data to read. Revert
this fix, so a complete fix for the problem can be cleanly
applied
* src/rpc/virnetclient.c: Revert fd06692544
Currently if you try to connect to a local libvirtd when
libvirtd is not in $PATH, you'll get an error
error: internal error invalid use of command API
This is because remoteFindDaemonPath() returns NULL, which
causes us to pass NULL into virNetSocketConnectUNIX which
in turn causes us to pass NULL into virCommandNewArgList.
Adding missing error checks improves this to
error: internal error Unable to locate libvirtd daemon in $PATH
* src/remote/remote_driver.c: Report error if libvirtd
cannot be found
* src/rpc/virnetsocket.c: Report error if caller requested
spawning of daemon, but provided no binary path
https://bugzilla.redhat.com/show_bug.cgi?id=648855 mentioned a
misuse of 'an' where 'a' is proper; that has since been fixed,
but a search found other problems (some were a spelling error for
'and', while most were fixed by 'a').
* daemon/stream.c: Fix grammar.
* src/conf/domain_conf.c: Likewise.
* src/conf/domain_event.c: Likewise.
* src/esx/esx_driver.c: Likewise.
* src/esx/esx_vi.c: Likewise.
* src/rpc/virnetclient.c: Likewise.
* src/rpc/virnetserverprogram.c: Likewise.
* src/storage/storage_backend_fs.c: Likewise.
* src/util/conf.c: Likewise.
* src/util/dnsmasq.c: Likewise.
* src/util/iptables.c: Likewise.
* src/xen/xen_hypervisor.c: Likewise.
* src/xen/xend_internal.c: Likewise.
* src/xen/xs_internal.c: Likewise.
* tools/virsh.c: Likewise.
The RPC fixups needed on Linux are also needed on cygwin, and
worked without further tweaking to the list of fixups. Also,
unlike BSD, Cygwin exports 'struct ifreq', but unlike Linux,
Cygwin lacks the ioctls that we were using 'struct ifreq' to
access. This patch allows compilation under cygwin.
* src/rpc/genprotocol.pl: Also perform fixups on cygwin.
* src/util/virnetdev.c (HAVE_STRUCT_IFREQ): Also require AF_PACKET
definition.
* src/util/virnetdevbridge.c (virNetDevSetupControlFull): Only
compile if SIOCBRADDBR works.
Originaly, the code checked if another client is the queue and infered
ownership of the buck from that. Commit fa9595003d
added a separate variable to track the buck. That caused, that a new
call might enter claiming it has the buck, while another thread was
signalled to take the buck. This ends in two threads claiming they hold
the buck and entering poll(). This happens due to a race on waking up
threads on the client lock mutex.
This caused multi-threaded clients to hang, most prominently visible and
reproducible on python based clients, like virt-manager.
This patch causes threads, that have been signalled to take the buck to
re-check if buck is held by another thread.
Detected by Coverity. Leak introduced in commit 673adba.
Two separate bugs here:
1. call was not freed on all error paths
2. virCondDestroy was called even if virCondInit failed
Signed-off-by: Alex Jia <ajia@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
When another thread was dispatching while we wanted to send a
non-blocking call, we correctly queued the call and woke up the thread
but the thread just threw the call away since it forgot to recheck if
its socket was writable.
When spawning an ssh connection, the environment variables
DISPLAY, SSH_ASKPASS, ... are passed. However XAUTHORITY,
which is necessary if the .Xauthority is in a non default
place, was not passed.
Signed-off-by: Christian Franke <nobody@nowhere.ws>
The keepalive program has two procedures: PING, and PONG.
Both are used only in asynchronous messages and the sender doesn't wait
for any reply. However, the party which receives PING messages is
supposed to react by sending PONG message the other party, but no
explicit binding between PING and PONG messages is made. For backward
compatibility neither server nor client are allowed to send keepalive
messages before checking that remote party supports them.
When virNetClientIOEventLoop is called for a non-blocking call and not
even a single byte can be sent from this call without blocking, we
properly reported that to the caller which properly frees the call. But
we never removed the call from a call queue.
Due to the asynchronous nature of streams, we might continue to
receive some stream packets from the server even after we have
shutdown the stream on the client side. These should be discarded
silently, rather than raising an error in the RPC layer.
* src/rpc/virnetclient.c: Discard stream data silently
Add a new virNetClientSendNonBlock which returns 2 on
full send, 1 on partial send, 0 on no send, -1 on error
If a partial send occurs, then a subsequent call to any
of the virNetClientSend* APIs will finish any outstanding
I/O.
TODO: the virNetClientEvent event handler could be used
to speed up completion of partial sends if an event loop
is present.
* src/rpc/virnetsocket.h, src/rpc/virnetsocket.c: Add new
virNetSocketHasPendingData() API to test for cached
data pending send.
* src/rpc/virnetclient.c, src/rpc/virnetclient.h: Add new
virNetClientSendNonBlock() API to send non-blocking API
Stop multiplexing virNetClientSend for two different purposes,
instead add virNetClientSendWithReply and virNetClientSendNoReply
* src/rpc/virnetclient.c, src/rpc/virnetclient.h: Replace
virNetClientSend with virNetClientSendWithReply and
virNetClientSendNoReply
* src/rpc/virnetclientprogram.c, src/rpc/virnetclientstream.c:
Update for new API names
Remove some duplication by pulling the code for passing the
buck out into a helper method
* src/rpc/virnetclient.c: Introduce virNetClientIOEventLoopPassTheBuck
Instead of inferring whether the buck is held from the waitDispatch
pointer, use an explicit 'bool haveTheBuck' field
* src/rpc/virnetclient.c: Explicitly track the buck
Directly messing around with the linked list is potentially
dangerous. Introduce some helper APIs to deal with list
manipulating the list
* src/rpc/virnetclient.c: Create linked list handlers
The src/util/network.c file is a dumping ground for many different
APIs. Split it up into 5 pieces, along functional lines
- src/util/virnetdevbandwidth.c: virNetDevBandwidth type & helper APIs
- src/util/virnetdevvportprofile.c: virNetDevVPortProfile type & helper APIs
- src/util/virsocketaddr.c: virSocketAddr and APIs
- src/conf/netdev_bandwidth_conf.c: XML parsing / formatting
for virNetDevBandwidth
- src/conf/netdev_vport_profile_conf.c: XML parsing / formatting
for virNetDevVPortProfile
* src/util/network.c, src/util/network.h: Split into 5 pieces
* src/conf/netdev_bandwidth_conf.c, src/conf/netdev_bandwidth_conf.h,
src/conf/netdev_vport_profile_conf.c, src/conf/netdev_vport_profile_conf.h,
src/util/virnetdevbandwidth.c, src/util/virnetdevbandwidth.h,
src/util/virnetdevvportprofile.c, src/util/virnetdevvportprofile.h,
src/util/virsocketaddr.c, src/util/virsocketaddr.h: New pieces
* daemon/libvirtd.h, daemon/remote.c, src/conf/domain_conf.c,
src/conf/domain_conf.h, src/conf/network_conf.c,
src/conf/network_conf.h, src/conf/nwfilter_conf.h,
src/esx/esx_util.h, src/network/bridge_driver.c,
src/qemu/qemu_conf.c, src/rpc/virnetsocket.c,
src/rpc/virnetsocket.h, src/util/dnsmasq.h, src/util/interface.h,
src/util/iptables.h, src/util/macvtap.c, src/util/macvtap.h,
src/util/virnetdev.h, src/util/virnetdevtap.c,
tools/virsh.c: Update include files
Send and receive string typed parameters across RPC. This also
completes the back-compat mentioned in the previous patch - the
only time we have an older client talking to a newer server is
if RPC is in use, so filtering out strings during RPC prevents
returning an unknown type to the older client.
* src/remote/remote_protocol.x (remote_typed_param_value): Add
another union value.
* daemon/remote.c (remoteDeserializeTypedParameters): Handle
strings on rpc.
(remoteSerializeTypedParameters): Likewise; plus filter out
strings when replying to older clients. Adjust callers.
* src/remote/remote_driver.c (remoteFreeTypedParameters)
(remoteSerializeTypedParameters)
(remoteDeserializeTypedParameters): Handle strings on rpc.
* src/rpc/gendispatch.pl: Properly clean up typed arrays.
* src/remote_protocol-structs: Update.
Based on an initial patch by Hu Tao, with feedback from
Daniel P. Berrange.
Signed-off-by: Eric Blake <eblake@redhat.com>
The socket address APIs in src/util/network.h either take the
form virSocketAddrXXX, virSocketXXX or virSocketXXXAddr.
Sanitize this so everything is virSocketAddrXXXX, and ensure
that the virSocketAddr parameter is always the first one.
* src/util/network.c, src/util/network.h: Santize socket
address API naming
* src/conf/domain_conf.c, src/conf/network_conf.c,
src/conf/nwfilter_conf.c, src/network/bridge_driver.c,
src/nwfilter/nwfilter_ebiptables_driver.c,
src/nwfilter/nwfilter_learnipaddr.c,
src/qemu/qemu_command.c, src/rpc/virnetsocket.c,
src/util/dnsmasq.c, src/util/iptables.c,
src/util/virnetdev.c, src/vbox/vbox_tmpl.c: Update for
API renaming
The code calling sendfd/recvfd was mistakenly assuming those
calls would never block. They can in fact return EAGAIN and
this is causing us to drop the client connection when blocking
ocurrs while sending/receiving FDs.
Fixing this is a little hairy on the incoming side, since at
the point where we see the EAGAIN, we already thought we had
finished receiving all data for the packet. So we play a little
trick to reset bufferOffset again and go back into polling for
more data.
* src/rpc/virnetsocket.c, src/rpc/virnetsocket.h: Update
virNetSocketSendFD/RecvFD to return 0 on EAGAIN, or 1
on success
* src/rpc/virnetclient.c: Move decoding of header & fds
out of virNetClientCallDispatch and into virNetClientIOHandleInput.
Handling blocking when sending/receiving FDs
* src/rpc/virnetmessage.h: Add a 'donefds' field to track
how many FDs we've sent / received
* src/rpc/virnetserverclient.c: Handling blocking when
sending/receiving FDs
I ran into the following build failure:
$ mkdir -p build1 build2/a/very/deep/hierarcy
$ cd build2/a/very/deep/hierarcy
$ ../../../../../configure && make
$ cd ../../../../build1
$ ../configure && make
...
../../src/remote/remote_protocol.c:7:55: fatal error: ../../../../../src/remote/remote_protocol.h: No such file or directory
Turns out that we were sometimes generating the remote_protocol.c
file with information from the VPATH build, which is bad, since
any file shipped in the tarball should be idempotent no matter how
deep the VPATH build tree that created it.
* src/rpc/genprotocol.pl: Don't embed VPATH into generated file.
If daemon is using SASL it reads client data into a cache. This cache is
big (usually 65KB) and can thus contain 2 or more messages. However,
on socket event we can dispatch only one message. So if we read two
messages at once, the second will not be dispatched as the socket event
goes away with filling the cache.
Moreover, when dispatching the cache we need to remember to take care
of client max requests limit.
