qemu driver in libvirt gained support for creating domain snapshots
almost a year ago in libvirt 0.8.0. Since then we enabled QMP support
for qemu >= 0.13.0 but QMP equivalents of {save,load,del}vm commands are
not implemented in current qemu (0.14.0) so the domain snapshot support
is not very useful.
This patch detects when the appropriate QMP command is not implemented
and tries to use human-monitor-command (aka HMP passthrough) to run
it's HMP equivalent.
JSON monitor command implementation can now just directly call text
monitor implementation and it will be automatically encapsulated into
QMP's human-monitor-command.
Some qemu monitor event handlers were issuing inadequate warning when
virDomainSaveStatus() failed. They copied the message from I/O error
handler without customizing it to provide better information on why
virDomainSaveStatus() was called.
For newer qemu-img, the help string for "backing file format" is
"[-F backing_fmt]".
Fix the wrong logic error by commit e997c268.
* src/storage/storage_backend.c
Adding audit points showed that we were granting too much privilege
to qemu; it should not need any mknod rights to recreate any
devices. On the other hand, lxc should have all device privileges.
The solution is adding a flag parameter.
This also lets us restrict write access to read-only disks.
* src/util/cgroup.h (virCgroup*Device*): Adjust prototypes.
* src/util/cgroup.c (virCgroupAllowDevice)
(virCgroupAllowDeviceMajor, virCgroupAllowDevicePath)
(virCgroupDenyDevice, virCgroupDenyDeviceMajor)
(virCgroupDenyDevicePath): Add parameter.
* src/qemu/qemu_driver.c (qemudDomainSaveFlag): Update clients.
* src/lxc/lxc_controller.c (lxcSetContainerResources): Likewise.
* src/qemu/qemu_cgroup.c: Likewise.
(qemuSetupDiskPathAllow): Also, honor read-only disks.
Although the cgroup device ACL controller path can be worked out
by researching the code, it is more efficient to include that
information directly in the audit message.
* src/util/cgroup.h (virCgroupPathOfController): New prototype.
* src/util/cgroup.c (virCgroupPathOfController): Export.
* src/libvirt_private.syms: Likewise.
* src/qemu/qemu_audit.c (qemuAuditCgroup): Use it.
Device names can be manipulated, so it is better to also log
the major/minor device number corresponding to the cgroup ACL
changes that libvirt made. This required some refactoring
of the relatively new qemu cgroup audit code.
Also, qemuSetupChardevCgroup was only auditing on failure, not success.
* src/qemu/qemu_audit.h (qemuDomainCgroupAudit): Delete.
(qemuAuditCgroup, qemuAuditCgroupMajor, qemuAuditCgroupPath): New
prototypes.
* src/qemu/qemu_audit.c (qemuDomainCgroupAudit): Rename...
(qemuAuditCgroup): ...and drop a parameter.
(qemuAuditCgroupMajor, qemuAuditCgroupPath): New functions, to
allow listing device major/minor in audit.
(qemuAuditGetRdev): New helper function.
* src/qemu/qemu_driver.c (qemudDomainSaveFlag): Adjust callers.
* src/qemu/qemu_cgroup.c (qemuSetupDiskPathAllow)
(qemuSetupHostUsbDeviceCgroup, qemuSetupCgroup)
(qemuTeardownDiskPathDeny): Likewise.
(qemuSetupChardevCgroup): Likewise, fixing missing audit.
* src/qemu/qemu_audit.c (qemuDomainHostdevAudit): Avoid use of
"type", which has a pre-defined meaning.
(qemuDomainCgroupAudit): Likewise, as well as "item".
I noticed these while testing 'make dist'.
Parsing ./../src/util/event.c
Function comment for virEventRegisterDefaultImpl lacks description of return value
Function comment for virEventRunDefaultImpl lacks description of return value
Parsing ./../src/util/virterror.c
Missing comment for function virSetErrorLogPriorityFunc
* src/util/event.c (virEventRegisterDefaultImpl)
(virEventRunDefaultImpl): Document return types.
* src/util/virterror.c (virSetErrorLogPriorityFunc): Provide docs.
virRun gives pretty useful error output, let's not overwrite it unless there
is a good reason. Some places were providing more information about what
the commands were _attempting_ to do, however that's usually less useful from
a debugging POV than what actually happened.
as described at
http://wiki.debian.org/ToolChain/DSOLinkinghttps://fedoraproject.org/wiki/UnderstandingDSOLinkChange
otherwise the build fails on current Debian unstable with:
CCLD libvirtd
/usr/bin/ld: ../src/.libs/libvirt_driver_lxc.a(libvirt_driver_lxc_la-lxc_container.o): undefined reference to symbol 'capng_apply'
/usr/bin/ld: note: 'capng_apply' is defined in DSO //usr/lib/libcap-ng.so.0 so try adding it to the linker command line
CCLD libvirtd
/usr/bin/ld: ../src/.libs/libvirt_driver_storage.a(libvirt_driver_storage_la-storage_backend.o): undefined reference to symbol 'fgetfilecon'
/usr/bin/ld: note: 'fgetfilecon' is defined in DSO //lib/libselinux.so.1 so try adding it to the linker command line
//lib/libselinux.so.1: could not read symbols: Invalid operation
and similar errors.
On cygwin:
CC libvirt_driver_security_la-security_dac.lo
security/security_dac.c: In function 'virSecurityDACSetProcessLabel':
security/security_dac.c:618: warning: format '%d' expects type 'int', but argument 7 has type 'uid_t' [-Wformat]
We've done this before (see src/util/util.c).
* src/security/security_dac.c (virSecurityDACSetProcessLabel): On
cygwin, uid_t is a 32-bit long.
On cygwin:
CC libvirt_util_la-cgroup.lo
util/cgroup.c: In function 'virCgroupKillRecursiveInternal':
util/cgroup.c:1458: warning: implicit declaration of function 'virCgroupNew' [-Wimplicit-function-declaration]
* src/util/cgroup.c (virCgroupKill): Don't build on platforms
where virCgroupNew is unsupported.
When building libvirt without libvirtd, I receive the following errors:
make[1]: Leaving directory `/home/wency/source/test/libvirt/src'
(cd daemon && make top_distdir=../libvirt-0.8.8 distdir=../libvirt-0.8.8/daemon \
am__remove_distdir=: am__skip_length_check=: am__skip_mode_fix=: distdir)
make[1]: Entering directory `/home/wency/source/test/libvirt/daemon'
make[1]: *** No rule to make target `libvirtd.8.in', needed by `distdir'. Stop.
This bug was caused by commit 6db98a2d.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
as described at
http://wiki.debian.org/ToolChain/DSOLinkinghttps://fedoraproject.org/wiki/UnderstandingDSOLinkChange
otherwise the build fails on current Debian unstable with:
CCLD virsh
/usr/bin/ld: virsh-virsh.o: undefined reference to symbol 'xmlSaveTree@@LIBXML2_2.6.8'
/usr/bin/ld: note: 'xmlSaveTree@@LIBXML2_2.6.8' is defined in DSO //usr/lib/libxml2.so.2 so try adding it to the linker command line
//usr/lib/libxml2.so.2: could not read symbols: Invalid operation
This is needed to detect situations when optional argument was
specified with non-integer value: '--int-opt foo'. To keep functions
uniform vshCommandOptString function was also changed, because it
returns tri-state value as well. Given result pointer is updated only
in case of success. If parsing fails, result is not updated at all.
Apparently some signals found on Unix are not exposed, this led
to a compilation failure
* src/util/logging.c: make code related to each signal dependant
upon the definition of that signal
The way to detach a USB disk is the same as that to detach a SCSI
disk. Rename this function and we can use it to detach a USB disk.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
When I use newest libvirt to save a domain, libvirtd will be deadlock.
Here is the output of gdb:
(gdb) thread 3
[Switching to thread 3 (Thread 0x7f972a1fc710 (LWP 30265))]#0 0x000000351fe0e034 in __lll_lock_wait () from /lib64/libpthread.so.0
(gdb) bt
at qemu/qemu_driver.c:2074
ret=0x7f972a1fbbe0) at remote.c:2273
(gdb) thread 7
[Switching to thread 7 (Thread 0x7f9730bcd710 (LWP 30261))]#0 0x000000351fe0e034 in __lll_lock_wait () from /lib64/libpthread.so.0
(gdb) bt
(gdb) p *(virMutexPtr)0x6fdd60
$2 = {lock = {__data = {__lock = 2, __count = 0, __owner = 30261, __nusers = 1, __kind = 0, __spins = 0, __list = {__prev = 0x0, __next = 0x0}},
__size = "\002\000\000\000\000\000\000\000\065v\000\000\001", '\000' <repeats 26 times>, __align = 2}}
(gdb) p *(virMutexPtr)0x1a63ac0
$3 = {lock = {__data = {__lock = 2, __count = 0, __owner = 30265, __nusers = 1, __kind = 0, __spins = 0, __list = {__prev = 0x0, __next = 0x0}},
__size = "\002\000\000\000\000\000\000\000\071v\000\000\001", '\000' <repeats 26 times>, __align = 2}}
(gdb) info threads
7 Thread 0x7f9730bcd710 (LWP 30261) 0x000000351fe0e034 in __lll_lock_wait () from /lib64/libpthread.so.0
6 Thread 0x7f972bfff710 (LWP 30262) 0x000000351fe0b43c in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
5 Thread 0x7f972b5fe710 (LWP 30263) 0x000000351fe0b43c in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
4 Thread 0x7f972abfd710 (LWP 30264) 0x000000351fe0b43c in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
* 3 Thread 0x7f972a1fc710 (LWP 30265) 0x000000351fe0e034 in __lll_lock_wait () from /lib64/libpthread.so.0
2 Thread 0x7f97297fb710 (LWP 30266) 0x000000351fe0b43c in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
1 Thread 0x7f9737aac800 (LWP 30260) 0x000000351fe0803d in pthread_join () from /lib64/libpthread.so.0
The reason is that we will try to lock some object in callback function, and we may call event API with locking the same object.
In the function virEventDispatchHandles(), we unlock eventLoop before calling callback function. I think we should
do the same thing in the function virEventCleanupTimeouts() and virEventCleanupHandles().
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Not all applications have an existing event loop they need
to integrate with. Forcing them to implement the libvirt
event loop integration APIs is an undue burden. This just
exposes our simple poll() based implementation for apps
to use. So instead of calling
virEventRegister(....callbacks...)
The app would call
virEventRegisterDefaultImpl()
And then have a thread somewhere calling
static bool quit = false;
....
while (!quit)
virEventRunDefaultImpl()
* daemon/libvirtd.c, tools/console.c,
tools/virsh.c: Convert to public event loop APIs
* include/libvirt/libvirt.h.in, src/libvirt_private.syms: Add
virEventRegisterDefaultImpl and virEventRunDefaultImpl
* src/util/event.c: Implement virEventRegisterDefaultImpl
and virEventRunDefaultImpl using poll() event loop
* src/util/event_poll.c: Add full error reporting
* src/util/virterror.c, include/libvirt/virterror.h: Add
VIR_FROM_EVENTS
The event loop implementation is used by more than just the
daemon, so move it into the shared area.
* daemon/event.c, src/util/event_poll.c: Renamed
* daemon/event.h, src/util/event_poll.h: Renamed
* tools/Makefile.am, tools/console.c, tools/virsh.c: Update
to use new virEventPoll APIs
* daemon/mdns.c, daemon/mdns.c, daemon/Makefile.am: Update
to use new virEventPoll APIs
The daemon code calls virEventAddHandleImpl directly instead
of calling the wrapper virEventAddHandle.
* tools/console.c, daemon/libvirtd.c, daemon/mdns.c: Convert to
use primary event APIs
* src/util/logging.c: fix virLogDumpAllFD() to avoid snprintf, simplify
the code and provide more useful signal descriptions. Also remove an
unused variable.
For qemu names the primary vga as "qxl-vga":
1) if vram is specified for 2nd qxl device:
-vga qxl -global qxl-vga.vram_size=$SIZE \
-device qxl,id=video1,vram_size=$SIZE,...
2) if vram is not specified for 2nd qxl device, (use the default
set by global):
-vga qxl -global qxl-vga.vram_size=$SIZE \
-device qxl,id=video1,...
For qemu names all qxl devices as "qxl":
1) if vram is specified for 2nd qxl device:
-vga qxl -global qxl.vram_size=$SIZE \
-device qxl,id=video1,vram_size=$SIZE ...
2) if vram is not specified for 2nd qxl device:
-vga qxl -global qxl-vga.vram_size=$SIZE \
-device qxl,id=video1,...
"-global" is the only way to define vram_size for the primary qxl
device, regardless of how qemu names it, (It's not good a good
way, as original idea of "-global" is to set a global default for
a driver property, but to specify vram for first qxl device, we
have to use it).
For other qxl devices, as they are represented by "-device", could
specify it directly and seperately for each, and it overrides the
default set by "-global" if specified.
v1 - v2:
* modify "virDomainVideoDefaultRAM" so that it returns 16M as the
default vram_size for qxl device.
* vram_size * 1024 (qemu accepts bytes for vram_size).
* apply default vram_size for qxl device for which vram_size is
not specified.
* modify "graphics-spice" tests (more sensiable vram_size)
* Add an argument of virDomainDefPtr type for qemuBuildVideoDevStr,
to use virDomainVideoDefaultRAM in qemuBuildVideoDevStr).
v2 - v3:
* Modify default video memory size for qxl device from 16M to 24M
* Update codes to be consistent with changes on qemu_capabilities.*
In case of imminent crash or upon request (signal USR2),
dump the logging buffer to the libvirtd.log file for
post-mortem analysis
* daemon/libvirtd.c: create a sig_fatal() handler connected to
SIGFPE SIGSEGV SIGILL SIGABRT SIGBUS and SIGUSR2, just dumping
the log buffer using virLogEmergencyDumpAll
virLogEmergencyDumpAll() allows to dump the content of the
debug buffer from within a signal handler. It saves to all
log file or stderr if none is found
* src/util/logging.h src/util/logging.c: add the new API
and cleanup the old virLogDump code
* src/libvirt_private.syms: exports it as a private symbol
As the file may grow quite a bit especially with debug turned on.
* daemon/libvirtd.logrotate.in daemon/Makefile.am libvirt.spec.in:
add new logrotate file for the daemon log
Syslog is not the best place to go search for libvirt error
logs, change it to a default file output libvirtd.log, but
still keep standard error if not run as a daemon.
Depending on whether it's run as root or user, the log is saved
in the local state dir or in $HOME/.libvirt.
* daemon/libvirtd.c: change default logging to go to libvirtd.log
Initially only the log actually written out by libvirt were
saved on the memory buffer, this patch forces all informations
including info and debug to be saved in memory too. This is
useful to get full data in case of crash.
This was also found while investigating
https://bugzilla.redhat.com/show_bug.cgi?id=670848
An EOF on a domain's monitor socket results in an event being queued
to handle the EOF. The handler calls qemuProcessHandleMonitorEOF. If
it is a transient domain, this leads to a call to
virDomainRemoveInactive, which removes the domain from the driver's
hashtable and unref's it. Nowhere in this code is the qemu driver lock
acquired.
However, all modifications to the driver's domain hashtable *must* be
done while holding the driver lock, otherwise the hashtable can become
corrupt, and (even more likely) another thread could call a different
hashtable function and acquire a pointer to the domain that is in the
process of being destroyed.
To prevent such a disaster, qemuProcessHandleMonitorEOF must get the
qemu driver lock *before* it gets the DomainObj's lock, and hold it
until it is finished with the DomainObj. This guarantees that nobody
else modifies the hashtable at the same time, and that anyone who had
already gotten the DomainObj from the hashtable prior to this call has
finished with it before we remove/destroy it.
This was found while researching the root cause of:
https://bugzilla.redhat.com/show_bug.cgi?id=670848
virDomainUnref should only be called with the lock held for the
virDomainObj in question. However, when a transient qemu domain gets
EOF on its monitor socket, it queues an event which frees the monitor,
which unref's the virDomainObj without first locking it. If another
thread has already locked the virDomainObj, the modification of the
refcount could potentially be corrupted. In an extreme case, it could
also be potentially unlocked by virDomainObjFree, thus left open to
modification by anyone else who would have otherwise waited for the
lock (not to mention the fact that they would be accessing freed
data!).
The solution is to have qemuMonitorFree lock the domain object right
before unrefing it. Since the caller to qemuMonitorFree doesn't expect
this lock to be held, if the refcount doesn't go all the way to 0,
qemuMonitorFree must unlock it after the unref.
