If we call virStreamFinish and virStreamAbort from 2 distinct
threads for example we can have access to freed memory.
Because when virStreamFinish finishes for example virStreamAbort
yet to be finished and it access virNetClientStreamPtr object
in stream->privateData.
Also it does not make sense to clear @driver field. After
stream is finished/aborted it is better to have appropriate
error message instead of "unsupported error".
This commit reverts [1] or virNetClientStreamPtr and
virStreamPtr will never be unrefed due to cyclic dependency.
Before this patch we don't have leaks because all execution
paths we call virStreamFinish or virStreamAbort.
[1] 8b6ffe40 : virNetClientStreamNew: Track origin stream
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
This mixing errors and EOF condition in one flag is odd.
Instead let's check st->err.code where appropriate.
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Checking virNetClientStreamRaiseError without client lock
is racy which is fixed in [1] for example. Thus let's remove such checks
when we are sending message to server. And in other cases
(like virNetClientStreamRecvHole for example) let's move the check
into client stream code.
virNetClientStreamRecvPacket already have stream lock so we could
introduce another error checking function like virNetClientStreamRaiseErrorLocked
but as error is set when both client and stream lock are hold we
can remove locking from virNetClientStreamRaiseError because all
callers hold either client or stream lock.
Also let's split virNetClientStreamRaiseErrorLocked into checking
state function and checking message send status function. They are
same yet.
[1] 1b6a29c21: rpc: fix race on stream abort/finish and server side abort
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Stream server error is not propagated if thread does not have the buck.
In case we have the buck we are ok due to the code added in [1].
Let's check for stream error on all paths. Now we don't need
to raise error in virNetClientCallDispatchStream.
Old code reported error only if the first message in wait
queue awaits reply. It is odd as depends on wait queue
situation. For example if we have only TX
message in queue and in one iteration loop both send the
message and receive error then thread sending TX message did
not receive the error. Next if we have RX message (first)
and TX message (second) in queue and in one iteration
loop both send the TX message and receive error then
thread sending TX message received error. In short
it was inconsistent. Let's report error whenever
we received it and for every type of message as it makes
sense to report errors as early as possible.
[1] 16c6e2b41: Fix propagation of RPC errors from streams
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
In next patches we'll add stream state checks to this
function that applicable to all call paths. This is handy
place because we hold client lock here.
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Stream abort/finish can hang because we can receive abort message
from server and yet sent abort/finish message to server. The latter
will not be answered ever because after server sends abort message
it forgets the stream and messages for unknown stream are simply ignored.
We check for stream error at the very beginning of remoteStreamFinish/remoteStreamAbort
but stream error can be set after the check in another thread operating
on stream. Let's check for stream error under client lock similar
to what's done in [1].
[1] 833b901cb: stream: Check for stream EOF
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Missing semicolon at the end of macros can confuse some analyzers
(like cppcheck <filename>). VIR_ONCE_GLOBAL_INIT is almost
exclusively called without an ending semicolon, but let's
standardize on using one like the other macros.
Add a dummy struct definition at the end of the macro, so
the compiler will require callers to add a semicolon.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
if virNetClientNew finishes with error before sock is set
to client object then sock does not get unrefed. This is
unexpected by function clients like virNetClientNewUNIX.
Let's make sure sock gets unrefed on any error path.
Next some clients like virNetClientNewLibSSH2 try to unref
sock on virNetClientNew errors. This is not correct even
before this patch because in some cases virNetClientNew
unrefed sock on error path by itself. Let's give up
sock managment to virNetClientNew entirely.
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Require that all headers are guarded by a symbol named
LIBVIRT_$FILENAME
where $FILENAME is the uppercased filename, with all characters
outside a-z changed into '_'.
Note we do not use a leading __ because that is technically a
namespace reserved for the toolchain.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This introduces a syntax-check script that validates header files use a
common layout:
/*
...copyright header...
*/
<one blank line>
#ifndef SYMBOL
# define SYMBOL
....content....
#endif /* SYMBOL */
For any file ending priv.h, before the #ifndef, we will require a
guard to prevent bogus imports:
#ifndef SYMBOL_ALLOW
# error ....
#endif /* SYMBOL_ALLOW */
<one blank line>
The many mistakes this script identifies are then fixed.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The make_nonnull_XXX methods can all fail due to OOM but this was being
silently ignored and thus also not checked by callers. Make the methods
propagate errors and use ATTRIBUTE_RETURN_CHECK to force callers to deal
with it.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
In many files there are header comments that contain an Author:
statement, supposedly reflecting who originally wrote the code.
In a large collaborative project like libvirt, any non-trivial
file will have been modified by a large number of different
contributors. IOW, the Author: comments are quickly out of date,
omitting people who have made significant contribitions.
In some places Author: lines have been added despite the person
merely being responsible for creating the file by moving existing
code out of another file. IOW, the Author: lines give an incorrect
record of authorship.
With this all in mind, the comments are useless as a means to identify
who to talk to about code in a particular file. Contributors will always
be better off using 'git log' and 'git blame' if they need to find the
author of a particular bit of code.
This commit thus deletes all Author: comments from the source and adds
a rule to prevent them reappearing.
The Copyright headers are similarly misleading and inaccurate, however,
we cannot delete these as they have legal meaning, despite being largely
inaccurate. In addition only the copyright holder is permitted to change
their respective copyright statement.
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This is a simple removal of a duplicated check of the return of the
filter function. There is a nested conditional checking exactly the same
thing since commit c9ede1cf removed the (ret > 0) check condition.
Signed-off-by: Julio Faracco <jcfaracco@gmail.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1631606
Changes made to manage and utilize a secondary connection
driver to APIs outside the scope of the primary connection
driver have resulted in some confusion processing polkit rules
since the simple "access denied" error message doesn't provide
enough of a clue when combined with the "authentication failed:
access denied by policy" as to which connection driver refused
or failed the ACL check.
In order to provide some context, let's modify the existing
"access denied" error returned from the various vir*EnsureACL
API's to provide the connection driver name that is causing
the failure. This should provide the context for writing the
polkit rules that would allow access via the driver, but yet
still adhere to the virAccessManagerSanitizeError commentary
regarding not telling the user why access was denied.
Signed-off-by: John Ferlan <jferlan@redhat.com>
This reverts commit ccc72d5cbd.
Based on upstream comment to a follow-up patch, this didn't take the
right approach and the right thing to do is revert and rework.
Signed-off-by: John Ferlan <jferlan@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1631606
Changes made to manage and utilize a secondary connection
driver to APIs outside the scope of the primary connection
driver have resulted in some confusion processing polkit rules
since the simple "access denied" error message doesn't provide
enough of a clue when combined with the "authentication failed:
access denied by policy" as to which connection driver refused
or failed the ACL check.
In order to provide some context, let's modify the existing
"access denied" error returne from the various vir*EnsureACL
API's to provide the connection driver name that is causing
the failure. This should provide the context for writing the
polkit rules that would allow access via the driver.
Signed-off-by: John Ferlan <jferlan@redhat.com>
ACKed-by: Michal Privoznik <mprivozn@redhat.com>
The result of libssh2_userauth_password is being assigned to 'ret' in
one branch and 'rc' in the other branch. Checks are all done against the
'ret' variable, so one branch never does the correct check.
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
If the same source gets built twice ('build same source on different
hosts at different times') the resulting files may differ.
Fix this by sorting the hash keys before usage.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
All of the ones being removed are pulled in by internal.h. The only
exception is sanlock which expects the application to include <stdint.h>
before sanlock's headers, because sanlock prototypes use fixed width
int, but they don't include stdint.h themselves, so we have to leave
that one in place.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Acked-by: Michal Privoznik <mprivozn@redhat.com>
It doesn't really make sense for us to have stdlib.h and string.h but
not stdio.h in the internal.h header.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Acked-by: Michal Privoznik <mprivozn@redhat.com>
Now that the virAuthGet*Path API's generate all the error messages
we can remove them from the callers.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
Semantically, there is no difference between an uninitialized worker
pool and an initialized worker pool with zero workers. Let's allow the
worker pool to be initialized for max_workers=0 as well then which
makes the API more symmetric and simplifies code. Validity of the
worker pool is delegated to virThreadPoolGetMaxWorkers instead.
This patch fixes segmentation faults in
virNetServerGetThreadPoolParameters and
virNetServerSetThreadPoolParameters for the case when no worker pool
is actually initialized (max_workers=0).
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Consider creating a listener socket from a hostname that resolves to
multiple addresses. It might be the case that the hostname resolves to
both an IPv4 and IPv6 address because it is reachable over both
protocols, but the IPv6 connectivity is provided off-host. In such a
case no local NIC will have IPv6 and so bind() would fail with the
EADDRNOTAVAIL errno. Thus it should be treated as non-fatal as long as
at least one socket was succesfully bound.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
When reporting socket/bind failures we want to ensure any fatal error
reported is as accurate as possible. We'll prefer reporting a bind()
errno over a socket() errno, because if socket() works but bind() fails
that is a more significant event.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Currently, the functions return a pointer to the
destination buffer on success or NULL on failure.
Not only does this kind of error handling look quite
alien in the context of libvirt, where most functions
return zero on success and a negative int on failure,
but it's also somewhat pointless because unless there's
been a failure the returned pointer will be the same
one passed in by the user, thus offering no additional
value.
Change the functions so that they return an int
instead.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
The include guard should match the file name and comment.
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
@srv must be unlocked for the call virNetServerProcessMsg otherwise a
deadlock can occur.
Since the pointer 'srv->workers' will never be changed after
initialization and the thread pool has it's own locking we can release
the lock of 'srv' earlier. This also fixes the deadlock.
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Replace instances where we previously called virGetLastError just to
either get the code or to check if an error exists with
virGetLastErrorCode to avoid a validity pre-check.
Signed-off-by: Ramy Elkest <ramyelkest@gmail.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Now that GnuTLS is a requirement, we can drop a lot of
conditionally built code. However, not all ifdef-s can go because
we still want libvirt_setuid to build without gnutls.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Since GnuTLS is required there is no way to go with !WITH_GNUTLS
branch and just distribute these files.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
After version 0.7.5, libssh deprecated the function scope
ssh_get_publickey() and moved to ssh_get_server_publickey(). So, Libvirt
is failing to compile using this new function name.
Signed-off-by: Julio Faracco <jcfaracco@gmail.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Rather than have virJSONValueArraySize return a -1 when the input
is not an array and then splat an error message, let's check for
an array before calling and then change the return to be a size_t
instead of ssize_t.
That means using the helper virJSONValueIsArray as well as using a
more generic error message such as "Malformed <something> array".
In some cases we can remove stack variables and when we cannot,
those variables should be size_t not ssize_t. Alter a few references
of if (!value) to be if (value == 0) instead as well.
Some callers can already assume an array is being worked on based
on the previous call, so there's less to do.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
So far we are repeating the following lines over and over:
if (!(virSomeObjectClass = virClassNew(virClassForObject(),
"virSomeObject",
sizeof(virSomeObject),
virSomeObjectDispose)))
return -1;
While this works, it is impossible to do some checking. Firstly,
the class name (the 2nd argument) doesn't match the name in the
code in all cases (the 3rd argument). Secondly, the current style
is needlessly verbose. This commit turns example into following:
if (!(VIR_CLASS_NEW(virSomeObject,
virClassForObject)))
return -1;
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Whenever we declare a new object the first member of the struct
has to be virObject (or any other member of that family). Now, up
until now we did not care about the name of the struct member.
But lets unify it so that we can do some checks at compile time
later.
The unified name is 'parent'.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Future commits rely on the presence of this callback.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Calling a push_privconn method to directly push the connection object
name into the arg list is inconvenient. Refactor so that we acquire
the connection variable name upfront, and push it to the arg list
separately. This allows various hardcoded usage of "priv->conn" to
be parameterized.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
When preparing for migration, the libxl driver creates a new TCP listen
socket for the incoming migration by calling virNetSocketNewListenTCP,
passing the destination host name. virNetSocketNewListenTCP calls
virSocketAddrParse to check if the host name is a wildcard address, in
which case it avoids adding the AI_ADDRCONFIG flag to the hints passed to
getaddrinfo. If the host name is not an IP address, virSocketAddrParse
reports an error
error : virSocketAddrParseInternal:121 : Cannot parse socket address
'myhost.example.com': Name or service not known
But virNetSocketNewListenTCP succeeds regardless and the overall migration
operation succeeds.
Introduce virSocketAddrParseAny and use it when simply testing if a host
name/addr is parsable.
Signed-off-by: Jim Fehlig <jfehlig@suse.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
If max_workers is set to zero, then the worker thread pool won't be
created, so when serializing state for pre-exec we must set various
parameters to zero.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Currently if the virNetServer instance is created with max_workers==0 to
request a non-threaded dispatch process, we deadlock during dispatch
#0 0x00007fb845f6f42d in __lll_lock_wait () from /lib64/libpthread.so.0
#1 0x00007fb845f681d3 in pthread_mutex_lock () from /lib64/libpthread.so.0
#2 0x000055a6628bb305 in virMutexLock (m=<optimized out>) at util/virthread.c:89
#3 0x000055a6628a984b in virObjectLock (anyobj=<optimized out>) at util/virobject.c:435
#4 0x000055a66286fcde in virNetServerClientIsAuthenticated (client=client@entry=0x55a663a7b960)
at rpc/virnetserverclient.c:1565
#5 0x000055a66286cc17 in virNetServerProgramDispatchCall (msg=0x55a663a7bc50, client=0x55a663a7b960,
server=0x55a663a77550, prog=0x55a663a78020) at rpc/virnetserverprogram.c:407
#6 virNetServerProgramDispatch (prog=prog@entry=0x55a663a78020, server=server@entry=0x55a663a77550,
client=client@entry=0x55a663a7b960, msg=msg@entry=0x55a663a7bc50) at rpc/virnetserverprogram.c:307
#7 0x000055a662871d56 in virNetServerProcessMsg (msg=0x55a663a7bc50, prog=0x55a663a78020, client=0x55a663a7b960,
srv=0x55a663a77550) at rpc/virnetserver.c:148
#8 virNetServerDispatchNewMessage (client=0x55a663a7b960, msg=0x55a663a7bc50, opaque=0x55a663a77550)
at rpc/virnetserver.c:227
#9 0x000055a66286e4c0 in virNetServerClientDispatchRead (client=client@entry=0x55a663a7b960)
at rpc/virnetserverclient.c:1322
#10 0x000055a66286e813 in virNetServerClientDispatchEvent (sock=<optimized out>, events=1, opaque=0x55a663a7b960)
at rpc/virnetserverclient.c:1507
#11 0x000055a662899be0 in virEventPollDispatchHandles (fds=0x55a663a7bdc0, nfds=<optimized out>)
at util/vireventpoll.c:508
#12 virEventPollRunOnce () at util/vireventpoll.c:657
#13 0x000055a6628982f1 in virEventRunDefaultImpl () at util/virevent.c:327
#14 0x000055a6628716d5 in virNetDaemonRun (dmn=0x55a663a771b0) at rpc/virnetdaemon.c:858
#15 0x000055a662864c1d in main (argc=<optimized out>,
#argv=0x7ffd105b4838) at logging/log_daemon.c:1235
Reviewed-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Currently virNetServerClientDispatchFunc implementations are only
responsible for free'ing the "msg" parameter upon success. Simplify the
calling convention by making it their unconditional responsibility to
free the "msg", and close the client if desired.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
There's no reason why the virNetServerClientDispatchRead method needs to
acquire an extra reference on the "client" object. An extra reference is
only needed if the registered dispatch callback is going to keep hold of
the "client" for work in the background. Thus we can push reference
acquisition into virNetServerDispatchNewMessage.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Ensure all enum cases are listed in switch statements.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
No sense in calling ServiceToggle for all nservices during
ServiceDispose since ServerClose calls ServiceClose which
removes the IOCallback that's being toggled via ServiceToggle.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
The position of various parameters changes depending on the WITH_GNUTLS
macro.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Since we annotate the APIs are having non-NULL parameters, we can remove
the checks for NULL in the code too.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
With the current code it is neccessary to call
virNetDaemonNewPostExecRestart()
and then for each server that needs restarting you are supposed
to call
virNetDaemonAddSeverPostExecRestart()
This is fine if there's only ever one server, but as soon as you
have two servers it is impossible to use this design. The code
has no idea which servers were recorded in the JSON state doc,
nor in which order the hash table serialized its keys.
So this patch changes things so that we only call
virNetDaemonNewPostExecRestart()
passing in a callback, which is invoked once for each server
found int he JSON state doc.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
It is not possible to blindly call virNetDaemonGetServer()
because in a post-exec restart scenario, some servers may
not exist and this method will pollute the error logs.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The server name and client data callbacks need to be non-NULL or the
system will crash at various times. This is particularly bad when some
of the crashes only occur post-exec restart.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virNetServer class is passing a pointer to itself to the
virNetServerClient as a 'void *' pointer. This is presumably due to fact
that the virnetserverclient.h file doesn't see the virNetServerPtr
typedef. The typedef is easily movable though, which lets us get
typesafe parameter passing, removing the confusion of passing two
distinct 'void *' pointers to one method.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virNetSocketWriteSASL method has to encode the buffer it is given and then
write it to the underlying socket. This write is not guaranteed to send the
full amount of data that was encoded by SASL. We cache the SASL encoded data so
that on the next invocation of virNetSocketWriteSASL we carry on sending it.
The subtle problem is that the 'len' value passed into virNetSocketWriteSASL on
the 2nd call may be larger than the original value. So when we've completed
sending the SASL encoded data we previously cached, we must return the original
length we encoded, not the new length.
This flaw means we could potentially have been discarded queued data without
sending it. This would have exhibited itself as a libvirt client never receiving
the reply to a method it invokes, async events silently going missing, or worse
stream data silently getting dropped.
For this to be a problem libvirtd would have to be queued data to send to the
client, while at the same time the TCP socket send buffer is full (due to a very
slow client). This is quite unlikely so if this bug was ever triggered by a real
world user it would be almost impossible to reproduce or diagnose, if indeed it
was ever noticed at all.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Replace virNetServerClientNeedAuth with
virNetServerClientIsAuthenticated because it makes it clearer what it
means.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
'Squash' virNetServerClientNeedAuthLocked into
virNetServerClientNeedAuth and remove virNetServerClientNeedAuthLocked
as it's not longer needed.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
There is a race between virNetServerProcessClients (main thread) and
remoteDispatchAuthList/remoteDispatchAuthPolkit/remoteSASLFinish (worker
thread) that can lead to decrementing srv->nclients_unauth when it's
zero. Since virNetServerCheckLimits relies on the value
srv->nclients_unauth the underrun causes libvirtd to stop accepting
new connections forever.
Example race scenario (assuming libvirtd is using policykit and the
client is privileged):
1. The client calls the RPC remoteDispatchAuthList =>
remoteDispatchAuthList is executed on a worker thread (Thread
T1). We're assuming now the execution stops for some time before
the line 'virNetServerClientSetAuth(client, 0)'
2. The client closes the connection irregularly. This causes the
event loop to wake up and virNetServerProcessClient to be
called (on the main thread T0). During the
virNetServerProcessClients the srv lock is hold. The condition
virNetServerClientNeedAuth(client) will be checked and as the
authentication is not finished right now
virNetServerTrackCompletedAuthLocked(srv) will be called =>
--srv->nclients_unauth => 0
3. The Thread T1 continues, marks the client as authenticated, and
calls virNetServerTrackCompletedAuthLocked(srv) =>
--srv->nclients_unauth => --0 => wrap around as nclient_unauth is
unsigned
4. virNetServerCheckLimits(srv) will disable the services forever
To fix it, add an auth_pending field to the client struct so that it
is now possible to determine if the authentication process has already
been handled for this client.
Setting the authentication method to none for the client in
virNetServerProcessClients is not a proper way to indicate that the
counter has been decremented, as this would imply that the client is
authenticated.
Additionally, adjust the existing test cases for this new field.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Combine virNetServerClientSetAuth(client,
VIR_NET_SERVER_SERVICE_AUTH_NONE) and virNetServerTrackCompletedAuth
into one new function named virNetServerSetClientAuthenticated.
After using this new function the function
virNetServerTrackCompletedAuth was superfluous and is therefore
removed. In addition, it is not very common that a
'{{function}}' (virNetServerTrackCompletedAuth) does more than just
the locking compared to
'{{function}}Locked' (virNetServerTrackCompletedAuthLocked).
virNetServerTrackPendingAuth was already superfluous and therefore
it's also removed.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
The lock for @client must not only be held for the duration of
checking whether the client wants to close, but also for as long as
we're closing the client. The same applies to the tracking of
authentications.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Add virNetServerClientAuthMethodImpliesAuthenticated() for deciding
whether a authentication method implies that a client is automatically
authenticated or not. Use this new function in
virNetServerClientNeedAuthLocked().
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
This makes the code more efficient.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Be more precise in which cases the authentication is needed and
introduce *Locked.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Add typedef for the anonymous enum used for the authentication methods
and remove the default case. This allows the usage of the type in a
switch statement and taking advantage of the compilers feature to
detect uncovered cases.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Stefan Zimmermann <stzi@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
So far clients were closed when disposing the daemon, after the state
driver cleanup. This was leading to libvirtd crashing at shutdown due
to missing driver.
Moving the client close in virNetServerClose() fixes the problem.
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Prior to this change, we relied solely on the inherited readonly
attribute of a service's socket. This only worked for our UNIX sockets
(and only to some degree), but doesn't work for TCP sockets which are RW
by default, but such connections support RO as well. This patch forces
an update on the client object once we have established a connection to
reflect the nature of the connection itself rather than relying on the
underlying socket's attributes.
Clients connected to the admin server have always been connected as RW
only.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1524399
Signed-off-by: Erik Skultety <eskultet@redhat.com>
After the virNetDaemonAddServerPostExec call in virtlogd we should have
netserver refcount set to 2. One goes to netdaemon servers hashtable
and one goes to virt{logd,lock} own reference to netserver. Let's add
the missing increment in virNetDaemonAddServerPostExec itself while
holding the daemon lock.
Since lockd defers management of the @srv object by the presence
in the hash table, virLockDaemonNewPostExecRestart must Unref the
alloc'd Ref on the @srv object done as part of virNetDaemonAddServerPostExec
and virNetServerNewPostExecRestart processing. The virNetDaemonGetServer
in lock_daemon main will also take a reference which is Unref'd during
main cleanup.
Right-aligning backslashes when defining macros or using complex
commands in Makefiles looks cute, but as soon as any changes is
required to the code you end up with either distractingly broken
alignment or unnecessarily big diffs where most of the changes
are just pushing all backslashes a few characters to one side.
Generated using
$ git grep -El '[[:blank:]][[:blank:]]\\$' | \
grep -E '*\.([chx]|am|mk)$$' | \
while read f; do \
sed -Ei 's/[[:blank:]]*[[:blank:]]\\$/ \\/g' "$f"; \
done
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
The packet with passed FD has the following format:
--------------------------
| len | header | payload |
--------------------------
where "payload" has an additional count of FDs before the actual data:
------------------
| nfds | payload |
------------------
When the packet is received we parse the "header", which as a side
effect updates msg->bufferOffset to point to the beginning of "payload".
If the message call contains FDs, we need to also parse the count of
FDs, which also updates the msg->bufferOffset.
The issue here is that when we attempt to read the FDs data from the
socket and we receive EAGAIN we finish the reading and call poll()
to wait for the data the we need. When the data arrives we already have
the packet in our buffer so we read the "header" again but this time
we don't read the count of FDs because we already have it stored.
That means that the msg->bufferOffset is not updated to point to the
actual beginning of the payload data, but it points to the count of
FDs. After all FDs are processed we dispatch the message to process
it and decode the payload. Since the msg->bufferOffset points to wrong
data, we decode the wrong payload and the API call fails with
error messages:
Domain not found: no domain with matching uuid '67656e65-7269-6300-0c87-5003ca6941f2' ()
Broken by commit 133c511b52 which fixed a FD and memory leak.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Seeing a log message saying 'flags=93' is ambiguous & confusing unless
you happen to know that libvirt always prints flags as hex. Change our
debug messages so that they always add a '0x' prefix when printing flags,
and '0' prefix when printing mode. A few other misc places gain a '0x'
prefix in error messages too.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This is particularly useful on operating systems that don't ship
Perl as part of the base system (eg. FreeBSD) while still working
just as well as it did before on Linux.
In one case (src/rpc/genprotocol.pl) the interpreter path was
missing altogether.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1487322
In ace45e67ab I tried to fix a problem that we get the reply to
a D-Bus call while we were sleeping. In that case the callback
was never set. So I changed the code that the callback is called
directly in this case. However, I hadn't realized that since the
callback is called out of order it locks the virNetDaemon.
Exactly the very same virNetDaemon object that we are dealing
with right now and that we have locked already (in
virNetDaemonAddShutdownInhibition())
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Inspired by the recent GIT / Mercurial security flaws
(http://blog.recurity-labs.com/2017-08-10/scm-vulns),
consider someone/something manages to feed libvirt a bogus
URI such as:
virsh -c qemu+ssh://-oProxyCommand=gnome-calculator/system
In this case, the hosname "-oProxyCommand=gnome-calculator"
will get interpreted as an argument to ssh, not a hostname.
Fortunately, due to the set of args we have following the
hostname, SSH will then interpret our bit of shell script
that runs 'nc' on the remote host as a cipher name, which is
clearly invalid. This makes ssh exit during argv parsing and
so it never tries to run gnome-calculator.
We are lucky this time, but lets be more paranoid, by using
'--' to explicitly tell SSH when it has finished seeing
command line options. This forces it to interpret
"-oProxyCommand=gnome-calculator" as a hostname, and thus
see a fail from hostname lookup.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
So there are couple of issues here. Firstly, we never unref the
@pendingReply and thus it leaks.
==13279== 144 (72 direct, 72 indirect) bytes in 1 blocks are definitely lost in loss record 1,095 of 1,259
==13279== at 0x4C2E080: calloc (vg_replace_malloc.c:711)
==13279== by 0x781FA97: _dbus_pending_call_new_unlocked (in /usr/lib64/libdbus-1.so.3.14.11)
==13279== by 0x7812A4C: dbus_connection_send_with_reply (in /usr/lib64/libdbus-1.so.3.14.11)
==13279== by 0x56BEDF3: virNetDaemonCallInhibit (virnetdaemon.c:514)
==13279== by 0x56BEF18: virNetDaemonAddShutdownInhibition (virnetdaemon.c:536)
==13279== by 0x12473B: daemonInhibitCallback (libvirtd.c:742)
==13279== by 0x1249BD: daemonRunStateInit (libvirtd.c:823)
==13279== by 0x554FBCF: virThreadHelper (virthread.c:206)
==13279== by 0x8F913D3: start_thread (in /lib64/libpthread-2.23.so)
==13279== by 0x928DE3C: clone (in /lib64/libc-2.23.so)
Secondly, while we send the message, we are suspended ('cos we're
talking to a UNIX socket). However, until we are resumed back
again the reply might have came therefore subsequent
dbus_pending_call_set_notify() has no effect and in fact the
virNetDaemonGotInhibitReply() callback is never called. Thirdly,
the dbus_connection_send_with_reply() has really stupid policy
for return values. To cite the man page:
Returns
FALSE if no memory, TRUE otherwise.
Yes, that's right. If anything goes wrong and it's not case of
OOM then TRUE is returned, i.e. you're trying to pass FDs and
it's not supported, or you're not connected, or anything else.
Therefore, checking for return value of
dbus_connection_send_with_reply() is not enoguh. We also have to
check if @pendingReply is not NULL before proceeding any further.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This reverts commit e4b980c853.
When a binary links against a .a archive (as opposed to a shared library),
any symbols which are marked as 'weak' get silently dropped. As a result
when the binary later runs, those 'weak' functions have an address of
0x0 and thus crash when run.
This happened with virtlogd and virtlockd because they don't link to
libvirt.so, but instead just libvirt_util.a and libvirt_rpc.a. The
virRandomBits symbols was weak and so left out of the virtlogd &
virtlockd binaries, despite being required by virHashTable functions.
Various other binaries like libvirt_lxc, libvirt_iohelper, etc also
link directly to .a files instead of libvirt.so, so are potentially
at risk of dropping symbols leading to a later runtime crash.
This is normal linker behaviour because a weak symbol is not treated
as undefined, so nothing forces it to be pulled in from the .a You
have to force the linker to pull in weak symbols using -u$SYMNAME
which is not a practical approach.
This risk is silent bad linkage that affects runtime behaviour is
not acceptable for a fix that was merely trying to fix the test
suite. So stop using __weak__ again.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
If we exceed a fixed limit in RPC code we get a horrible message
like this, if the parameter type is a 'string', because we forgot
to initialize the error message type field:
$ virsh snapshot-list ostack1
error: too many remote undefineds: 1329 > 1024
It would also be useful to know which RPC call and field was
exceeded. So this patch makes us report:
$ virsh snapshot-list ostack1
error: too many remote undefineds: 1329 > 1024,
in parameter 'names' for 'virDomainSnapshotListNames'
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently all mockable functions are annotated with the 'noinline'
attribute. This is insufficient to guarantee that a function can
be reliably mocked with an LD_PRELOAD. The C language spec allows
the compiler to assume there is only a single implementation of
each function. It can thus do things like propagating constant
return values into the caller at compile time, or creating
multiple specialized copies of the function body each optimized
for a different caller. To prevent these optimizations we must
also set the 'noclone' and 'weak' attributes.
This fixes the test suite when libvirt.so is built with CLang
with optimization enabled.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The log category for virnetdaemon.c was mistakenly set
to rpc.netserver. Some useful info about the inhibitor
file descriptor was also never logged.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The DBus conditional was renamed way back:
commit da77f04ed5
Author: Daniel P. Berrange <berrange@redhat.com>
Date: Thu Sep 20 15:05:39 2012 +0100
Convert HAVE_DBUS to WITH_DBUS
but the shutdown inhibit code was not updated. Thus libvirt
was never inhibiting shutdown by a logged in user when VMs
are running.
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Use ATTRIBUTE_FALLTHROUGH, introduced by commit
5d84f5961b, instead of comments to
indicate that the fall through is an intentional behavior.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
While reworking client side of streams, I had to postpone payload
decoding so that stream holes and stream data can be
distinguished in virNetClientStreamRecvPacket. That's merely what
18944b7aea does. However, I accidentally removed one important
bit: when server sends us an empty STREAM packet (with no
payload) - meaning end of stream - st->incomingEOF flag needs to
be set. It used to be before I touched the code. After I removed
it, virNetClientStreamRecvPacket will try to fetch more data from
the stream, but it will never come.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>
When increasing the buffer size up to VIR_NET_MESSAGE_MAX, we
currently quadruple it each time. This unfortunately means that we
cannot allow certain buffer sizes -- for example the current
VIR_NET_MESSAGE_MAX == 33554432 can never be "hit" since ‘newlen’
jumps from 16MB to 64MB.
Instead of quadrupling, double it each time.
Thanks: Daniel Berrange.
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
While most of the APIs are okay with 16M messages, the bulk stats API
can run into the limit in big configurations. Before we devise a new
plan for this, bump this limit slightly to accomodate some more configs.
Currently, we don't assign any meaning to that. Our current view
on virStream is that it's merely a pipe. And pipes don't support
seeking.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Now, not all APIs are going to support sparse streams. To some it
makes no sense at all, e.g. virDomainOpenConsole() or
virDomainOpenChannel(). To others, we will need a special flag to
indicate that client wants to enable sparse streams. Instead of
having to write RPC dispatchers by hand we can just annotate in
our .x files that a certain flag to certain RPC call enables this
feature. For instance:
/**
* @generate: both
* @readstream: 1
* @sparseflag: VIR_SPARSE_STREAM
* @acl: storage_vol:data_read
*/
REMOTE_PROC_DOMAIN_SOME_API = XXX,
Therefore, whenever client calls virDomainSomeAPI(..,
VIR_SPARSE_STREAM); daemon will mark that down and send stream
skips when possible.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Whenever server sends a client stream packet (either regular with
actual data or stream skip one) it is queued on @st->rx. So the
list is a mixture of both types of stream packets. So now that we
have all the helpers needed we can wire their processing up. But
since virNetClientStreamRecvPacket doesn't support
VIR_STREAM_RECV_STOP_AT_HOLE flag yet, let's turn all received
skips into zeroes repeating requested times.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This is a function that handles an incoming STREAM_HOLE packet.
Even though it is not wired up yet, it will be soon. At the
beginning do couple of checks whether server plays nicely and
sent us a STREAM_HOLE packed only after we've enabled sparse
streams. Then decodes the message payload to see how big the hole
is and stores it in passed @length argument.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
While the previous commit implemented a helper for sending a
STREAM_HOLE packet for daemon, this is a client's counterpart.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This is just a helper function that takes in a length value,
encodes it into XDR and sends to client.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This is a special type of stream packet, that is bidirectional
and contains information regarding how many bytes each side will
be skipping in the stream.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Add a new argument to daemonCreateClientStream in order to allow for
future expansion to mark that a specific stream can be used to skip
data, such as the case with sparsely populated files. The new flag will
be the eventual decision point between client/server to decide whether
both ends can support and want to use sparse streams.
A new bool 'allowSkip' is added to both _virNetClientStream and
daemonClientStream in order to perform the tracking.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Add a virStreamPtr pointer to the _virNetClientStream
in order to reverse track the parent stream.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
When we get a POLLHUP or VIR_EVENT_HANDLE_HANGUP event for a client, we
still want to read from the socket to process any accumulated data. But
doing so inevitably results in an error and a call to
virNetClientMarkClose before we get to processing the hangup event (and
another call to virNetClientMarkClose). However the close reason passed
to the second virNetClientMarkClose call is ignored because another one
was already set. We need to pass the correct close reason when marking
the socket to be closed for the first time.
https://bugzilla.redhat.com/show_bug.cgi?id=1373859
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
ka maybe have been freeed in virObjectUnref, application using
virKeepAliveTimer will segfault when unlock ka. We should keep
ka's refs positive before using it.
#0 0x00007fd8f79970e8 in virClassIsDerivedFrom (klass=0xdeadbeef, parent=0x7fd8e8001b80) at util/virobject.c:169
#1 0x00007fd8f799742e in virObjectIsClass (anyobj=anyobj entry=0x7fd8e800b9c0, klass=＜optimized out＞) at util/virobject.c:365
#2 0x00007fd8f79974e4 in virObjectUnlock (anyobj=0x7fd8e800b9c0) at util/virobject.c:338
#3 0x00007fd8f7ac477e in virKeepAliveTimer (timer=＜optimized out＞, opaque=0x7fd8e800b9c0) at rpc/virkeepalive.c:177
#4 0x00007fd8f7e5c9cf in libvirt_virEventInvokeTimeoutCallback () from /usr/lib64/python2.7/site-packages/libvirtmod.so
#5 0x00007fd8ff64db94 in PyEval_EvalFrameEx () from /lib64/libpython2.7.so.1.0
#6 0x00007fd8ff64f1ad in PyEval_EvalCodeEx () from /lib64/libpython2.7.so.1.0
#7 0x00007fd8ff64d85f in PyEval_EvalFrameEx () from /lib64/libpython2.7.so.1.0
#8 0x00007fd8ff64d950 in PyEval_EvalFrameEx () from /lib64/libpython2.7.so.1.0
#9 0x00007fd8ff64d950 in PyEval_EvalFrameEx () from /lib64/libpython2.7.so.1.0
#10 0x00007fd8ff64f1ad in PyEval_EvalCodeEx () from /lib64/libpython2.7.so.1.0
#11 0x00007fd8ff5dc098 in function_call () from /lib64/libpython2.7.so.1.0
#12 0x00007fd8ff5b7073 in PyObject_Call () from /lib64/libpython2.7.so.1.0
#13 0x00007fd8ff5c6085 in instancemethod_call () from /lib64/libpython2.7.so.1.0
#14 0x00007fd8ff5b7073 in PyObject_Call () from /lib64/libpython2.7.so.1.0
#15 0x00007fd8ff648ff7 in PyEval_CallObjectWithKeywords () from /lib64/libpython2.7.so.1.0
#16 0x00007fd8ff67d7e2 in t_bootstrap () from /lib64/libpython2.7.so.1.0
#17 0x00007fd8ff358df3 in start_thread () from /lib64/libpthread.so.0
#18 0x00007fd8fe97d3ed in clone () from /lib64/libc.so.6
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
In the RPC client event loop code, if poll() returns only a POLLHUP
or POLLERR status, then we end up reporting a bogus error message:
error: failed to connect to the hypervisor
error: An error occurred, but the cause is unknown
We do actually report an error, but we virNetClientMarkClose method
has already captured the error status before we report it, so the
real error gets thrown away. The key fix is to report the error
before calling virNetClientMarkClose(). In changing this, we also
split out reporting of POLLHUP vs POLLERR to make any future bugs
easier to diagnose.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Apple have annotated all SASL functions as deprecated for
unknown reasons. Since they still work, lets just ignore
the warnings. If Apple finally delete the SASL functions
our configure check should already catch that
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
CLang's optimizer is more aggressive at inlining functions than
gcc and so will often inline functions that our tests want to
mock-override. This causes the test to fail in bizarre ways.
We don't want to disable inlining completely, but we must at
least prevent inlining of mocked functions. Fortunately there
is a 'noinline' attribute that lets us control this per function.
A syntax check rule is added that parses tests/*mock.c to extract
the list of functions that are mocked (restricted to names starting
with 'vir' prefix). It then checks that src/*.h header file to
ensure it has a 'ATTRIBUTE_NOINLINE' annotation. This should prevent
use from bit-rotting in future.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Commit 252610f7dd switched to use hash to store servers.
Function virHashGetItems returns allocated array which needs
to be freed also for successful path, not only if there is
an error.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Use the return value of virObjectRef directly. This way, it's easier
for another reader to identify the reason why the additional reference
is required.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
If the SASL config does not have any mechanisms we currently
just report an empty list to the client which will then
fail to identify a usable mechanism. This is a server config
error, so we should fail immediately on the server side.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
We have to allocate first and if, and only if, it was successful we
can set the count. A segfault has occurred in
virNetServerServiceNewPostExecRestart() when VIR_ALLOC_N(svc->socks,
n) has failed, but svc->nsocsk = n was already set. Thus
virObejectUnref(svc) was called and therefore it was possible that
virNetServerServiceDispose was called => segmentation fault. For
safeness NULL pointer check were added in
virNetServerServiceDispose().
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
When composing the path to the default known_hosts file (for the libssh
and libssh2 drivers), do not check whether the configuration directory
(determined by virGetUserConfigDirectory()) exists: both the drivers can
handle non-existing files, and are able to create them (and their
directories) in that case.
This adds a small behaviour change: before, the key for an unknown host,
and manually accepted, was saved only if the configuration directory
existed -- a bit incoherent behaviour though.
If any of them is specified for the libssh and libssh2 drivers, there is
no need to depend on checks based on other paths: in particular, a
specified path for known_hosts was ignored if the local config directory
could not be determined, and the path for keyfile was ignored if the
home could not be determined.
Instead, lazily determine and use these two paths only in case they are
needed.
Make sure that virNetLibsshSessionSetHostKeyVerification accepts a NULL
value for the path to the known_hosts file:
- call ssh_options_set(SSH_OPTIONS_KNOWNHOSTS) anyway, using /dev/null,
otherwise libssh will use its default path
- do not call ssh_write_knownhost when no known hosts file was set
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1406457
Implement in virtNetClient and VirNetSocket the needed functions to
expose a new libssh transport, providing all the options that the
libssh2 transport supports.
Implement a new libssh transport, which uses libssh to communicate with
remote hosts, and add all the build system stuff (search of libssh,
private symbols, etc) to built it.
This new transport supports all the common ssh authentication methods,
making use of libvirt's auth callbacks for interaction with the user.
Add a couple of helper functions to check whether one of the default
names of SSH keys (as documented in ssh-keygen(1)) exists, and use them
to specify a key for the libssh2 transport if none was passed.
Add an internal variable to mark the FD as "not owned" by the
virNetSocket, in case the internal implementation takes the actual
ownership of the descriptor; this avoids a warning when closing the
socket, as the FD would be invalid.
Prior to commit 2737aaaf, we allowed every client to connect successfully,
however, if accepting a client would eventually lead to an overcommit of the
limits, we would disconnect it immediately with "Too many active clients,
dropping connection from...". Recent changes refactored the code in a way, that
it is not possible for the client-related callback to be dispatched and the
client to be accepted if the limits wouldn't permit to do so, therefore a check
if a connection should be dropped due to limits violation has become a dead
code that could be removed.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Commit 2737aaaf changed our policy for accepting new clients in a way, that
instead of accepting new clients only to disconnect them immediately, since
that would overcommit the limit, we temporarily disable polling for the
dedicated file descriptor, so any new connection will queue on the socket.
Commit 8b1f0469 then added the possibility to change the limits during runtime
but it didn't re-enable polling for the previously disabled file descriptor,
thus any new connection would still continue to queue on the socket. This patch
forces an update of the services each time the limits were changed in some way.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1357776
Signed-off-by: Erik Skultety <eskultet@redhat.com>
So far, virNetServerCheckLimits was only used to possibly re-enable accepting
new clients that might have previously been disabled due to client limits
violation (max_clients, max_anonymous_clients). This patch refactors
virNetServerAddClient, which is currently the only place where the services get
disabled, in order to use the virNetServerCheckLimits helper instead of
checking the limits by itself.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Since virNetServerAddClient checks for the limits in order to temporarily
suspend the services, thus not accepting any more clients, there is no reason
why virNetServerCheckLimits, which is only responsible for re-enabling
previously disabled services according to the limits, could not do both. To be
able to do that however, it needs to be moved up in the file since it's static
(and because it's just a helper and there's only one caller it should remain
static).
Signed-off-by: Erik Skultety <eskultet@redhat.com>
virNetServerClientGetInfo returns the client's remote address
as a string, which is a part of the client object.
Use VIR_STRDUP to make a copy which can be freely accessed
even after the virNetServerClient object is unlocked.
To reproduce, put a sleep between virObjectUnlock in
virNetServerClientGetInfo and virTypedParamsAddString in
adminClientGetInfo, then close the queried connection during
that sleep.
Use it in virNetServerClientGetInfo to switch back to using
the URI-format (separated by ':') instead of the SASL format
(separated by ';').
Also use it in the error message reported by virNetServerAddClient.
This partially reverts commit 9b45c9f049.
It changed the default format of socket address from the one SASL
requires, but did not adjust all the callers.
It also removed the test coverage for it.
Revert most of the changes except the virSocketAddrFormatFull support
for URI-formatted strings.
This fixes https://bugzilla.redhat.com/show_bug.cgi?id=1345743 while
reverting the format used by virt-admin's client-info command from
the URI one to the SASL one.
https://bugzilla.redhat.com/show_bug.cgi?id=1345743
Since it's rather tedious to write the dispatchers for functions that
return an array of typed parameters (which are rather common) let's add
some rpcgen code to generate them.
Extend the virNetTLSContextNew* constructors to allow
the TLS priority string to be passed in, overriding the
compile time default.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently libvirt calls gnutls_set_default_priority()
which on old systems resolves to "NORMAL" while new
systems it resolves to "@SYSTEM". Either way, this
is a global default that is identical across all apps.
We want to allow distros to flexibility to define a
custom default string for libvirt priority, so add
a --tls-priority=STRING flag to configure to enable
this to be set.
It is expected that distros would use this when creating
RPM/Deb/etc packages, according to their preferred crypto
handling policies.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Currently we set the gnutls log function when creating a
TLS context, however, the setting is in fact global, not
per context. So we should be setting it when we first call
gnutls_global_init() instead.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
We need to use the gnutls_priority_set_direct method which
was not introduced until 2.1.7, so bump version to 2.2.0
which is the first stable release with it included. This
release dates from Dec 2007 so it is reasonable to ditch
support for the 1.x.x series for gnutls releases entirely.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Opposite operation to virAdmServerGetClientLimits. Understandably though,
setting values for current number of clients connected or still waiting
for authentication does not make sense, since changes to these values are event
dependent, i.e. a client connects - counter is increased. Thus only the limits
to maximum clients connected and waiting for authentication can be set. Should
a request for other controls to be set arrive (provided such a setting will
be first introduced to the config), the set of configuration controls can be
later expanded (thanks to typed params). This patch also introduces a
constraint that the maximum number of clients waiting for authentication has to
be less than the overall maximum number of clients connected and any attempt to
violate this constraint will be denied.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Add some trivial getters for client related attributes to virnetserver before
any admin method can be introduced.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
This removes the opencoded payload freeing in the client, to use
the shared virNetMessageClearPayload call. Two changes:
- ClearPayload sets nfds=0, which fixes a potential crash if
an error path called virNetMessageFree/Clear on the message
after fds was free'd
- We drop the inner loop VIR_FORCE_CLOSE... this may mean fds are
kept open a little bit longer if the call is blocking but in
practice I don't think it will have any effect
I've noticed this while trying to compile libvirt on my arm box.
CC rpc/libvirt_net_rpc_server_la-virnetserverclient.lo
rpc/virnetserverclient.c: In function 'virNetServerClientNewPostExecRestart':
rpc/virnetserverclient.c:516:45: error: cast increases required alignment of target type [-Werror=cast-align]
(long long *) ×tamp) < 0) {
^
cc1: all warnings being treated as errors
Problem is, @timestap is defined as time_t which is 32 bits long,
and we are typecasting it to long long which is 64bits long.
Solution is to make @timestamp type of long long. At the same
time, we can make @conn_time in _virNetServerClient struct long
long too. There is no need for it to be type of time_t.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
In this function, @id is defined as unsigned long long. When
passing this variable to virJSONValueObjectGetNumberUlong(),
well address of this variable, it's typecasted to ull*. There
is no need for that. It's a same story with @nrequests_max.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This method just aggregates various client object attributes, like socket
address, connection type (RO/RW), and some TCP/TLS/UNIX identity in an atomic
manner.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
We do have a similar method, serving the same purpose, for TLS, but we lack
one for SASL. So introduce one, in order for other modules to be able to find
out, if a SASL session is active, or better said, that a SASL session exists
at all.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Our socket address format is in a rather non-standard format and that is
because sasl library requires the IP address and service to be delimited by a
semicolon. The string form is a completely internal matter, however once the
admin interfaces to retrieve client identity information are merged, we should
return the socket address string in a common format, e.g. format defined by
URI rfc-3986, i.e. the IP address and service are delimited by a colon and
in case of an IPv6 address, square brackets are added:
Examples:
127.0.0.1:1234
[::1]:1234
This patch changes our default format to the one described above, while adding
separate methods to request the non-standard SASL format using semicolon as a
delimiter.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Just like with server-related APIs, before any of client-based APIs can be
called, a reference to a client-side client object needs to be obtained. For
this purpose, a lookup method should exist. Apart from the client retrieval
logic, a new error code for non-existent client had to be added as well.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Although we document 6 types of transport that we support, internally we can
only differentiate between TCP, TLS, and UNIX transports only, since both SSH
and libssh2 transports, due to using netcat, behave in the exactly the same
way as a UNIX socket.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
For now, the list copy is done simply by locking the whole server, walking the
original and increasing the refcount on each object. We may want to change
the list to a lockable object (like list of domains) later in the future if
we discover some performance issues related to locking the whole server in
order to walk the whole list of clients, possibly issuing some 'ForEach'
callback.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Now that libvirt-admin supports another client-side object and provided that
we want to generate as many both client-side and server-side RPC dispatchers,
support for this needs to be added to gendispatch.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Besides ID, libvirt should provide several parameters to help the user
distinguish two clients from each other. One of them is the connection
timestamp. This patch also adds a testcase for proper JSON formatting of the
new attribute too (proper formatting of older clients that did not support
this attribute yet is included in the existing tests) - in order to
testGenerateJSON to work, a mock of time_t time(time_t *timer) needed to be
created.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Admin API needs a way of addressing specific clients. Unlike servers, which we
are happy to address by names both because its name reflects its purpose (to
some extent) and we only have two of them (so far), naming clients doesn't make
any sense, since a) each client is an anonymous, i.e. not recognized after a
disconnect followed by a reconnect, b) we can't predict what kind of requests
it's going to send to daemon, and c) the are loads of them comming and going,
so the only viable option is to use an ID which is of a reasonably wide data
type.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
There are two functions on the client that handle incoming stream
data. The first one virNetClientStreamQueuePacket() is a low
level function that just processes the incoming stream data from
the socket and stores it into an internal structure. This happens
in the client event loop therefore the shorter the callbacks are,
the better. The second function virNetClientStreamRecvPacket()
then handles copying data from internal structure into a client
provided buffer.
Change introduced in this commit makes just that: new queue for
incoming stream packets is introduced. Then instead of copying
data into intermediate internal buffer and then copying them into
user buffer, incoming stream messages are queue into the queue
and data is copied just once - in the upper layer function
virNetClientStreamRecvPacket(). In the end, there's just one
copying of data and therefore shorter event loop callback. This
should boost the performance which has proven to be the case in
my testing.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This reverts commit d9c9e138f2.
Unfortunately, things are going to be handled differently so this
commit must go.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
FD passing APIs like CreateXMLWithFiles or OpenGraphicsFD will leak
file descriptors. The user passes in an fd, which is dup()'d in
virNetClientProgramCall. The new fd is what is transfered to the
server virNetClientIOWriteMessage.
Once all the fds have been written though, the parent msg->fds list
is immediately free'd, so the individual fds are never closed.
This closes each FD as its send to the server, so all fds have been
closed by the time msg->fds is free'd.
https://bugzilla.redhat.com/show_bug.cgi?id=1159766
The stream serial number is the serial number of the RPC call
that initiated a data transfer. And as such can never be
negative. Moreover, when looking up internal state for a stream,
the serial numbers are compared. But hey, the serial number in
message header is unsigned too!
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Since threadpool increments the current number of threads according to current
load, i.e. how many jobs are waiting in the queue. The count however, is
constrained by max and min limits of workers. The logic of this new API works
like this:
1) setting the minimum
a) When the limit is increased, depending on the current number of
threads, new threads are possibly spawned if the current number of
threads is less than the new minimum limit
b) Decreasing the minimum limit has no possible effect on the current
number of threads
2) setting the maximum
a) Icreasing the maximum limit has no immediate effect on the current
number of threads, it only allows the threadpool to spawn more
threads when new jobs, that would otherwise end up queued, arrive.
b) Decreasing the maximum limit may affect the current number of
threads, if the current number of threads is less than the new
maximum limit. Since there may be some ongoing time-consuming jobs
that would effectively block this API from killing any threads.
Therefore, this API is asynchronous with best-effort execution,
i.e. the necessary number of workers will be terminated once they
finish their previous job, unless other workers had already
terminated, decreasing the limit to the requested value.
3) setting priority workers
- both increase and decrease in count of these workers have an
immediate impact on the current number of workers, new ones will be
spawned or some of them get terminated respectively.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
New API to retrieve current server workerpool specs. Since it uses typed
parameters, more specs to retrieve can be further included in the pool of
supported ones.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Trying to reload/SIGUSR1 virtlogd or virtlockd fails with:
error : virNetDaemonRun:747 : internal error: Not all servers restored, cannot run server
Commit 252610f7 changed the daemon state json to allow tracking
multiple servers. However it missed clearing dmn->srvObject after
the json is empty, like the previous code paths handled. Later on in
virNewDaemonRun, dmn->srvObject is expected to be empty otherwise we
throw the above error.
https://bugzilla.redhat.com/show_bug.cgi?id=1311013
fdstream.c: In function 'virFDStreamWrite':
fdstream.c:390:29: error: logical 'or' of equal expressions [-Werror=logical-op]
if (errno == EAGAIN || errno == EWOULDBLOCK) {
^~
Fedora rawhide now uses gcc 6.0 and there is a bug with -Wlogical-op
producing false warnings.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69602
Use GCC pragma push/pop and ignore -Wlogical-op for GCC that supports
push/pop pragma and also has this bug.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Compilation for xdg-app failed due to a buggy SASL headers present on
the used runtime (org.gnome.Sdk 3.18).
In file included from rpc/virnetsaslcontext.h:24:0,
from rpc/virnetsaslcontext.c:25:
/usr/include/sasl/sasl.h:230:38: error: unknown type name 'size_t'
typedef void *sasl_realloc_t(void *, size_t);
^
/usr/include/sasl/sasl.h:235:5: error: unknown type name 'sasl_realloc_t'
sasl_realloc_t *,
Use the same workaround as commit 1be3dfd did.
Signed-off-by: Ján Tomko <jtomko@redhat.com>
The adminDispatchConnectListServers() function is generated by
our great perl script. However, it has a tiny flaw: if
adminConnectListServers() it calls fails, the control jumps onto
cleanup label where we try to free any list of servers built so
far. However, in the loop @i is unsigned (size_t) while @nresults
is signed (int). Currently, it does no harm because of the check
for @result being non-NULL. But if that ever changes in the
future, this bug will be hard to chase.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1271183
We only wait 0.5 seconds for the session daemon to start up and present
its socket, which isn't sufficient for many users. Bump up the sleep
interval and retry amount so we wait for a total of 5.0 seconds.
Let's call it modern_ret_as_list as opposed to single_ret_as_list. The
latter was able to return list of things. However the new, more modern,
version came and it is used since listAllDomains till nowadays in
ListServers.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
We were using parentheses for grouping admin|remote even though we didn't
need to capture what's in it. That caused some changes to be greater
than needed and, to be honest, some confusion as well. Let's use it as
it should be used. It'll also make future changes more consistent.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
For now it does not matter which ones we return as the code is similarly
complex, however it will fit in with other constructs in the future,
mainly when we will be able to generate dispatch helpers.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
virHashForEach() returns 0 if everything went nice, so our session
daemon was timing out even when there was a client connected.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1315606
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Since servers know their name, there is no need to supply such
information twice. Also defeats inconsistencies.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
At first I did not want to do this, but after trying to implement some
newer feaures in the admin API I realized we need that to make our lives
easier. On the other hand they are not saved redundantly and the
virNetServer objects are still kept in a hash table.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
This API is merely a convenience API, i.e. when managing clients connected to
daemon's servers, we should know (convenience) which server the specific client
is connected to. This implies a client-side representation of a server along
with a basic API to let the administrating client know what servers are actually
available on the daemon.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Since the daemon can manage and add (at fresh start) multiple servers,
we also should be able to add them from a JSON state file in case of a
daemon restart, so post exec restart support for multiple servers is also
provided. Patch also updates virnetdaemontest accordingly.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Apparently we are not the only ones with dumb free functions
because dbus_message_unref() does not accept NULL either. But if
I were to vote, this one is even more evil. Instead of returning
an error just like we do it immediately dereference any pointer
passed and thus crash you app. Well done DBus!
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7f878ebda700 (LWP 31264)]
0x00007f87be4016e5 in ?? () from /usr/lib64/libdbus-1.so.3
(gdb) bt
#0 0x00007f87be4016e5 in ?? () from /usr/lib64/libdbus-1.so.3
#1 0x00007f87be3f004e in dbus_message_unref () from /usr/lib64/libdbus-1.so.3
#2 0x00007f87bf6ecf95 in virSystemdGetMachineNameByPID (pid=9849) at util/virsystemd.c:228
#3 0x00007f879761bd4d in qemuConnectCgroup (driver=0x7f87600a32a0, vm=0x7f87600c7550) at qemu/qemu_cgroup.c:909
#4 0x00007f87976386b7 in qemuProcessReconnect (opaque=0x7f87600db840) at qemu/qemu_process.c:3386
#5 0x00007f87bf6edfff in virThreadHelper (data=0x7f87600d5580) at util/virthread.c:206
#6 0x00007f87bb602334 in start_thread (arg=0x7f878ebda700) at pthread_create.c:333
#7 0x00007f87bb3481bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109
(gdb) frame 2
#2 0x00007f87bf6ecf95 in virSystemdGetMachineNameByPID (pid=9849) at util/virsystemd.c:228
228 dbus_message_unref(reply);
(gdb) p reply
$1 = (DBusMessage *) 0x0
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Commit 8cd1d54 consolidates both daemon and remote driver typed param
serialization functions. The consolidation now enforces client to use
VIR_TYPED_PARAM_STRING_OKAY flag to properly serialize string parameters, which
server has used for quite some time now. And this caused an issue, since the
commit had not adjusted client remote calls appropriately, thus causing a
failure in blkiotune, numatune and migration APIs (as per Xen CI tests). This
patch adjusts both remote_driver.c and gendispatch.pl to properly address this
issue.
http://lists.xenproject.org/archives/html/xen-devel/2016-02/msg01012.html
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Same as for deserializer, this method might get handy for admin one day.
The major reason for this patch is to stay consistent with idea, i.e.
when deserializer can be shared, why not serializer as well. The only
problem to be solved was that the daemon side serializer uses a code
snippet which handles sparse arrays returned by some APIs as well as
removes any string parameters that can't be returned to older clients.
This patch makes of the new virTypedParameterRemote datatype introduced
by one of the pvious patches.
Since the method is static to remote_driver, it can't even be used by our
daemon. Other than that, it would be useful to be able to use it with admin as
well. This patch uses the new virTypedParameterRemote datatype introduced in
one of previous patches.
Currently, the deserializer is hardcoded into remote_driver which makes
it impossible for admin to use it. One way to achieve a shared implementation
(besides moving the code to another module) would be pass @ret_params_val as a
void pointer as opposed to the remote_typed_param pointer and add a new extra
argument specifying which of those two protocols is being used and typecast
the pointer at the function entry. An example from remote_protocol:
struct remote_typed_param_value {
int type;
union {
int i;
u_int ui;
int64_t l;
uint64_t ul;
double d;
int b;
remote_nonnull_string s;
} remote_typed_param_value_u;
};
typedef struct remote_typed_param_value remote_typed_param_value;
struct remote_typed_param {
remote_nonnull_string field;
remote_typed_param_value value;
};
That would leave us with a bunch of if-then-elses that needed to be used across
the method. This patch takes the other approach using the new datatype
introduced in one of earlier commits.
In our generator for some code we put empty lines in the output
to separate blocks of code. However, in some cases we put couple
of spaces on the empty line too. It's not bug, it just isn't
nice.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The generated output is dependent on perl hashtable ordering, which
gives different results for i686 and x86_64. Fix this by sorting
the hash keys before iterating over them
https://bugzilla.redhat.com/show_bug.cgi?id=1173641
On every socket connect(2) attempt we were re-launching session
libvirtd, up to 100 times in 5 seconds.
This understandably caused some weird load races and intermittent
qemu:///session startup failures
https://bugzilla.redhat.com/show_bug.cgi?id=1271183
When we autolaunch libvirtd for session URIs, we spin in a retry
loop waiting for the daemon to start and the connect(2) to succeed.
However if we exceed the retry count, we don't explicitly raise an
error, which can yield a slew of different error messages elsewhere
in the code.
Explicitly raise the last connect(2) failure if we run out of retries.
