Commit Graph

490 Commits

Author SHA1 Message Date
Eric Blake
44aa49aefe util: remove dead assignment
Clang complained about this, and it was easy enough to fix.

* src/util/util.c (virFileOpenAs): Drop dead assignment.
2011-05-04 09:25:07 -06:00
Eric Blake
ead2b43357 cgroup: avoid leaking a file
Clang detected a dead store to rc.  It turns out that in fixing this,
I also found a FILE* leak.

This is a subtle change in behavior, although unlikely to hit.  The
pidfile is a kernel file, so we've probably got more serious problems
under foot if we fail to parse one.  However, the previous behavior
was that even if one pid file failed to parse, we tried others,
whereas now we give up on the first failure.  Either way, though,
the function returns -1, so the caller will know that something is
going wrong, and that not all pids were necessarily reaped.  Besides,
there were other instances already in the code where failure in the
inner loop aborted the outer loop.

* src/util/cgroup.c (virCgroupKillInternal): Abort rather than
resuming loop on fscanf failure, and cleanup file on error.
2011-05-04 08:38:27 -06:00
Eric Blake
1164e1a2da pci: fix null pointer dereference
Clang detected a null-pointer dereference regression, introduced
in commit 4e8969eb.  Without this patch, a device with
unbind_from_stub set to false would eventually try to call
virFileExists on uncomputed drvdir.

* src/util/pci.c (pciUnbindDeviceFromStub): Ensure drvdir is set
before use.
2011-05-03 10:59:57 -06:00
Matthias Bolte
9d50b323a9 Fix memory leak in __virExec
Commit e0d014f237 made binary potentially allocated on the heap.
It was freed in the parent in the error path, but not in the success path
that doesn't goto the cleanup label.

Found by 'make -C tests valgrind'.
2011-04-30 17:37:29 +02:00
Eric Blake
701bee0193 hash: fix memory leak regression
Commit 1671d1d introduced a memory leak in virHashFree, and
wholesale table corruption in virHashRemoveSet (elements not
requested to be freed are lost).

* src/util/hash.c (virHashFree): Free bucket array.
(virHashRemoveSet): Don't lose elements.
* tests/hashtest.c (testHashCheckForEachCount): New method.
(testHashCheckCount): Expose the bug.
2011-04-29 14:26:40 -06:00
Laine Stump
f7bd72fa26 network: fix return value of hostsFileWrite
The lone caller to hostsFileWrite (and the callers for at least 3
levels up the return stack) assume that the return value will be < 0
on failure. However, hostsFileWrite returns 0 on success, and a
positive errno on failure. This patch changes hostsFileWrite to return
-errno on failure.
2011-04-28 10:44:57 -04:00
Eric Blake
a372c405b4 maint: fix comment typos
* src/esx/esx_driver.c: Fix spelling of 'relative'.
* src/util/util.c: Likewise.
2011-04-28 08:19:51 -06:00
Osier Yang
32398e1282 util: Initialize hooks at daemon shutdown if no hooks defined
We support to initialize the hooks at daemon reload if there is no
hooks script is defined, we should also support initialize the hooks
at daemon shutdown if no hooks is defined.

To address bz: https://bugzilla.redhat.com/show_bug.cgi?id=688859
2011-04-28 14:48:26 +08:00
Jiri Denemark
1671d1dc78 util: Simplify hash implementation
So far first entries for each hash key are stored directly in the hash
table while other entries mapped to the same key are linked through
pointers. As a result of that, the code is cluttered with special
handling for the first items.

This patch makes all entries (even the first ones) linked through
pointers, which significantly simplifies the code and makes it more
maintainable.
2011-04-27 15:32:30 +02:00
Jiri Denemark
91e12a5094 tests: More unit tests for internal hash APIs
This adds several tests for remaining hash APIs (custom
hasher/comparator functions are not covered yet, though).

All tests pass both before and after the "Simplify hash implementation".
2011-04-27 15:32:30 +02:00
Wen Congyang
6fee3da262 free buf->content when vsnprintf() failed
When buf->error is 1, we do not return buf->content in the function
virBufferContentAndReset(). So we should free buf->content when
vsnprintf() failed.
2011-04-27 20:12:13 +08:00
Matthias Bolte
3ba5d77f3c Move call to virReportOOMError into virFileBuildPath
Suggested by Daniel P. Berrange
2011-04-27 09:18:53 +02:00
Eric Blake
59a5981dd3 build: use gnulib passfd for simpler SCM_RIGHTS code
* .gnulib: Update to latest for passfd fixes.
* bootstrap.conf (gnulib_modules): Add passfd.
* src/util/util.c (virFileOpenAs): Simplify.
2011-04-26 10:36:56 -06:00
Eric Blake
90d761eeb2 build: make VIR_FREE do some type checking
We can exploit the fact that gcc warns about int-to-pointer conversion
in ternary cond?(void*):(int) in order to prevent future mistakes of
calling VIR_FREE on a scalar lvalue.  For example, between commits
158ba873 and 802e2df, we would have had this warning:

cc1: warnings being treated as errors
remote.c: In function 'remoteDispatchListNetworks':
remote.c:3684:70: error: pointer/integer type mismatch in conditional expression

There are still a number of places that malloc into a const char*;
while it would probably be worth scrubbing them to use char*
instead, that is a separate patch, so we have to cast away const
in VIR_FREE for now.

* src/util/memory.h (VIR_FREE): Make gcc warn about integers.
Iteratively developed from a patch by Christophe Fergeau.
2011-04-25 10:20:18 -06:00
Eric Blake
99de59900a threads: add one-time initialization support
mingw lacks the counterpart to PTHREAD_MUTEX_INITIALIZER, so the
best we can do is portably expose once-only runtime initialization.

* src/util/threads.h (virOnceControlPtr): New opaque type.
(virOnceFunc): New callback type.
(virOnce): New prototype.
* src/util/threads-pthread.h (virOnceControl): Declare.
(VIR_ONCE_CONTROL_INITIALIZER): Define.
* src/util/threads-win32.h (virOnceControl)
(VIR_ONCE_CONTROL_INITIALIZER): Likewise.
* src/util/threads-pthread.c (virOnce): Implement in pthreads.
* src/util/threads-win32.c (virOnce): Implement in WIN32.
* src/libvirt_private.syms: Export it.
2011-04-25 08:53:09 -06:00
Matthias Bolte
78ef49eae3 Update and sort msg_gen_function list and mark unmarked messages
Inspired by Eric Blake
2011-04-18 19:05:15 +02:00
Matthias Bolte
60d769a13a Remove virConnectPtr from virRaiseErrorFull
And from all related macros and functions.
2011-04-17 07:22:23 +02:00
Eric Blake
dbe3bad987 maint: use lighter-weight function for straight appends
It costs quite a few processor cycles to go through printf parsing
just to determine that we only meant to append.

* src/xen/xend_internal.c (xend_op_ext): Consolidate multiple
printfs into one.
* src/qemu/qemu_command.c (qemuBuildWatchdogDevStr)
(qemuBuildUSBInputDevStr, qemuBuildSoundDevStr)
(qemuBuildSoundCodecStr, qemuBuildVideoDevStr): Likewise.
(qemuBuildCpuArgStr, qemuBuildCommandLine): Prefer virBufferAdd
over virBufferVsprintf for trivial appends.
* src/phyp/phyp_driver.c (phypExec, phypUUIDTable_Push)
(phypUUIDTable_Pull): Likewise.
* src/conf/nwfilter_conf.c (macProtocolIDFormatter)
(arpOpcodeFormatter, formatIPProtocolID, printStringItems)
(virNWFilterPrintStateMatchFlags, virNWIPAddressFormat)
(virNWFilterDefFormat): Likewise.
* src/security/virt-aa-helper.c (main): Likewise.
* src/util/sexpr.c (sexpr2string): Likewise.
* src/xenxs/xen_sxpr.c (xenFormatSxprChr): Likewise.
* src/xenxs/xen_xm.c (xenFormatXMDisk): Likewise.
2011-04-15 15:26:26 -06:00
Christophe Fergeau
454e50beee Fix gcc 4.6 warnings
gcc 4.6 warns when a variable is initialized but isn't used afterwards:

vmware/vmware_driver.c:449:18: warning: variable 'vmxPath' set but not used [-Wunused-but-set-variable]

This patch fixes these warnings. There are still 2 offending files:

- vbox_tmpl.c: the variable is used inside an #ifdef and is assigned several
  times outside of #ifdef. Fixing the warning would have required wrapping
  all the assignment inside #ifdef which hurts readability.

vbox/vbox_tmpl.c: In function 'vboxAttachDrives':
vbox/vbox_tmpl.c:3918:22: warning: variable 'accessMode' set but not used [-Wunused-but-set-variable]

- esx_vi_types.generated.c: the name implies it's generated code and I
  didn't want to dive into the code generator

esx/esx_vi_types.generated.c: In function 'esxVI_FileQueryFlags_Free':
esx/esx_vi_types.generated.c:1203:3: warning: variable 'item' set but not used [-Wunused-but-set-variable]
2011-04-14 19:09:12 +02:00
Jiri Denemark
5c53160a2f util: Fix crash when removing entries during hash iteration
Commit 9677cd33ee made it possible to
remove current entry when iterating through all hash entries. However,
it didn't properly handle a special case of removing first entry
assigned to a given key which contains several entries in its collision
list.
2011-04-12 19:18:08 +02:00
Eric Blake
99fa30804b maint: fix grammar errors
Jim Meyering recently improved gnulib to catch various grammar
errors during 'make syntax-check'.

* .gnulib: Update to latest, for syntax-check improvements.
* include/libvirt/libvirt.h.in (virConnectAuthCallbackPtr): Use
cannot rather than two words.
* src/driver.c: Likewise.
* src/driver.h (VIR_SECRET_GET_VALUE_INTERNAL_CALL): Likewise.
* src/remote/remote_driver.c (initialize_gnutls): Likewise.
* src/util/pci.c (pciBindDeviceToStub): Likewise.
* src/storage/storage_backend.c (virStorageBackendCreateQemuImg):
Likewise.
(virStorageBackendUpdateVolTargetInfoFD): Avoid doubled word.
* docs/formatdomain.html.in: Likewise.
* src/qemu/qemu_process.c (qemuProcessStart): Likewise.
* cfg.mk (exclude_file_name_regexp--sc_prohibit_can_not)
(exclude_file_name_regexp--sc_prohibit_doubled_word): Exclude
existing translation problems.
2011-04-12 09:06:14 -06:00
Eric Blake
8ae5df5d93 virsh: fix mingw startup
* .gnulib: Update to latest, for pipe2.
* bootstrap.conf (gnulib_modules): Add pipe2.
* src/util/event_poll.c (virEventPollInit): Use it, to avoid
problematic virSetCloseExec on mingw.
2011-04-07 15:13:24 -06:00
Wen Congyang
4e8969ebcf reattach pci device when pciBindDeviceToStub() failed
We should bind pci device to original driver when pciBindDeviceToStub() failed.
If the pci device is not bound to any driver before calling pciBindDeviceToStub(),
we should only unbind it from pci-stub. If it is bound to pci-stub, we should not
unbind it from pci-stub.
2011-04-07 13:09:46 +08:00
Wen Congyang
9121b1930f rename pciUnBindDeviceFromStub() to pciUnbindDeviceFromStub() and float it up
This patch do the following things:
1. rename the function as 'Unbind' is better than 'UnBind'.
2. pciUnbindDeviceFromStub() will be used in the function pciBindDeviceToStub() in
   next patch. Float it up, instead of having to have a forward declaration
2011-04-07 13:09:46 +08:00
Wen Congyang
d5981f1caf pci: avoid invalid free, init path to NULL
This bug was introduce by commit 57162db8, and it will cause libvirtd crashed.
2011-04-07 13:09:39 +08:00
Eric Blake
f6447e8a54 build: avoid compiler warning on cygwin
In file included from util/threads.c:31:
util/threads-pthread.c: In function 'virThreadSelfID':
util/threads-pthread.c:214: warning: cast from function call of type 'pthread_t' to non-matching type 'int' [-Wbad-function-cast]

* src/util/threads-pthread.c (virThreadSelfID) [!SYS_gettid]:
Add intermediate cast to silence gcc.
2011-04-06 17:07:23 -06:00
Daniel P. Berrange
5b099250e3 Avoid compiler warnings about int -> void * casts
GCC is a little confused about the cast of beginthread/beginthreadex
from unsigned long -> void *. Go via an intermediate variable avoids
the bogus warning, and makes the code a little cleaner

* src/util/threads-win32.c: Avoid compiler warning in cast
2011-04-05 17:43:33 +01:00
Matthias Bolte
9e3550dc4e Use virBufferPtr for sexpr2string instead of manual buffer handling
Removes 4kb stack allocation in the XenD subdriver.
2011-04-05 09:14:59 +02:00
Matthias Bolte
25f85e4938 Remove PATH_MAX sized stack allocation from virFileOpenTtyAt 2011-04-05 09:10:32 +02:00
Matthias Bolte
859efe7f88 ebtables: Remove PATH_MAX sized stack allocation 2011-04-05 08:55:27 +02:00
Matthias Bolte
57162db82c pci: Remove PATH_MAX sized stack allocations
Use virAsprintf instead of snprintf.
2011-04-05 08:55:27 +02:00
Matthias Bolte
1573158190 Remove PATH_MAX sized stack allocations related to virFileBuildPath
Make virFileBuildPath operate on the heap instead of the stack. It
allocates a buffer instead of expecting a preexisting buffer.
2011-04-05 08:55:27 +02:00
Eric Blake
0d166c6b7c build: detect potentential uninitialized variables
Even with -Wuninitialized (which is part of autobuild.sh
--enable-compile-warnings=error), gcc does NOT catch this
use of an uninitialized variable:

{
  if (cond)
    goto error;
  int a = 1;
error:
  printf("%d", a);
}

which prints 0 (supposing the stack started life wiped) if
cond was true.  Clang will catch it, but we don't use clang
as often.  Using gcc -Wjump-misses-init catches it, but also
gives false positives:

{
  if (cond)
    goto error;
  int a = 1;
  return a;
error:
  return 0;
}

Here, a was never used in the scope of the error block, so
declaring it after goto is technically fine (and clang agrees).
However, given that our HACKING already documents a preference
to C89 decl-before-statement, the false positive warning is
enough of a prod to comply with HACKING.

[Personally, I'd _really_ rather use C99 decl-after-statement
to minimize scope, but until gcc can efficiently and reliably
catch scoping and uninitialized usage bugs, I'll settle with
the compromise of enforcing a coding standard that happens to
reject false positives if it can also detect real bugs.]

* acinclude.m4 (LIBVIRT_COMPILE_WARNINGS): Add -Wjump-misses-init.
* src/util/util.c (__virExec): Adjust offenders.
* src/conf/domain_conf.c (virDomainTimerDefParseXML): Likewise.
* src/remote/remote_driver.c (doRemoteOpen): Likewise.
* src/phyp/phyp_driver.c (phypGetLparNAME, phypGetLparProfile)
(phypGetVIOSFreeSCSIAdapter, phypVolumeGetKey)
(phypGetStoragePoolDevice)
(phypVolumeGetPhysicalVolumeByStoragePool)
(phypVolumeGetPath): Likewise.
* src/vbox/vbox_tmpl.c (vboxNetworkUndefineDestroy)
(vboxNetworkCreate, vboxNetworkDumpXML)
(vboxNetworkDefineCreateXML): Likewise.
* src/xenapi/xenapi_driver.c (getCapsObject)
(xenapiDomainDumpXML): Likewise.
* src/xenapi/xenapi_utils.c (createVMRecordFromXml): Likewise.
* src/security/security_selinux.c (SELinuxGenNewContext):
Likewise.
* src/qemu/qemu_command.c (qemuBuildCommandLine): Likewise.
* src/qemu/qemu_hotplug.c (qemuDomainChangeEjectableMedia):
Likewise.
* src/qemu/qemu_process.c (qemuProcessWaitForMonitor): Likewise.
* src/qemu/qemu_monitor_text.c (qemuMonitorTextGetPtyPaths):
Likewise.
* src/qemu/qemu_driver.c (qemudDomainShutdown)
(qemudDomainBlockStats, qemudDomainMemoryPeek): Likewise.
* src/storage/storage_backend_iscsi.c
(virStorageBackendCreateIfaceIQN): Likewise.
* src/node_device/node_device_udev.c (udevProcessPCI): Likewise.
2011-04-04 11:26:29 -06:00
Eric Blake
da3c471467 virsh: fix mingw failure on creating nonblocking pipe
* .gnulib: Update to latest, for nonblocking module.
* bootstrap.conf (gnulib_modules): Add nonblocking.
* src/util/util.c (virSetBlocking): Defer to gnulib.
2011-04-01 08:43:10 -06:00
Jiri Denemark
72ab0b6dc8 qemu: Ignore libvirt debug messages in qemu log
qemu driver uses a 4K buffer for reading qemu log file. This is enough
when only qemu's output is present in the log file. However, when
debugging messages are turned on, intermediate libvirt process fills the
log with a bunch of debugging messages before it executes qemu binary.
In such a case the buffer may become too small. However, we are not
really interested in libvirt messages so they can be filtered out from
the buffer.
2011-04-01 08:48:32 +02:00
Daniel P. Berrange
7300f68dff Add public APIs for storage volume upload/download
New APIs are added allowing streaming of content to/from
storage volumes.

* include/libvirt/libvirt.h.in: Add virStorageVolUpload and
  virStorageVolDownload APIs
* src/driver.h, src/libvirt.c, src/libvirt_public.syms: Stub
  code for new APIs
* src/storage/storage_driver.c, src/esx/esx_storage_driver.c:
  Add dummy entries in driver table for new APIs
2011-03-29 12:17:33 +01:00
Daniel P. Berrange
e886237af5 Enhance the streams helper to support plain file I/O
The O_NONBLOCK flag doesn't work as desired on plain files
or block devices. Introduce an I/O helper program that does
the blocking I/O operations, communicating over a pipe that
can support O_NONBLOCK

* src/fdstream.c, src/fdstream.h: Add non-blocking I/O
  on plain files/block devices
* src/Makefile.am, src/util/iohelper.c: I/O helper program
* src/qemu/qemu_driver.c, src/lxc/lxc_driver.c,
  src/uml/uml_driver.c, src/xen/xen_driver.c: Update for
  streams API change
2011-03-29 12:17:28 +01:00
Eric Blake
16a4243c19 build: fix compilation on mingw
* src/util/command.c (virCommandAbort) [WIN32]: Provide stub.
Reported by Daniel P. Berrange's autobuilder.
2011-03-28 14:12:28 -06:00
Eric Blake
fa3e1e35eb util: adjust indentation in previous patch
Separating the indentation from the real patch made review easier.

* src/util/util.c (virFileOpenAs): Whitespace changes.
2011-03-28 10:26:33 -06:00
Eric Blake
1fdd50f999 util: rename virFileOperation to virFileOpenAs
This patch intentionally doesn't change indentation, in order to
make it easier to review the real changes.

* src/util/util.h (VIR_FILE_OP_RETURN_FD, virFileOperationHook):
Delete.
(virFileOperation): Rename...
(virFileOpenAs): ...and reduce parameters.
* src/util/util.c (virFileOperationNoFork, virFileOperation):
Rename and simplify.
* src/qemu/qemu_driver.c (qemudDomainSaveFlag): Adjust caller.
* src/storage/storage_backend.c (virStorageBackendCreateRaw):
Likewise.
* src/libvirt_private.syms: Reflect rename.
2011-03-28 10:26:33 -06:00
Eric Blake
055d4ff87c util: use SCM_RIGHTS in virFileOperation when needed
Currently, the hook function in virFileOperation is extremely limited:
it must be async-signal-safe, and cannot modify any memory in the
parent process.  It is much handier to return a valid fd and operate
on it in the parent than to deal with hook restrictions.

* src/util/util.h (VIR_FILE_OP_RETURN_FD): New flag.
* src/util/util.c (virFileOperationNoFork, virFileOperation):
Honor new flag.
2011-03-28 10:26:33 -06:00
Eric Blake
296eb0bbe3 util: allow clearing cloexec bit
* src/util/util.h (virSetInherit): New prototype.
* src/util/util.c (virSetCloseExec): Move guts...
(virSetInherit): ...to new function, and allow clearing.
* src/libvirt_private.syms (util.h): Export it.
2011-03-28 10:26:32 -06:00
Eric Blake
60dea30b7d logging: always NUL-terminate circular buffer
* src/util/logging.c (virLogStartup, virLogSetBufferSize):
Over-allocate, so that a debugger can just print the circular
buffer.  Suggested by Daniel Veillard.
2011-03-28 10:14:06 -06:00
Eric Blake
42a0fc39c1 hooks: fix regression in previous patch
* src/util/hooks.c (virHookCheck): Missing hooks should just be
debug, not warn.
2011-03-25 15:15:11 -06:00
Eric Blake
9ed545185f command: add virCommandAbort for cleanup paths
Sometimes, an asynchronous helper is started (such as a compressor
or iohelper program), but a later error means that we want to
abort that child.  Make this easier.

Note that since daemons and virCommandRunAsync can't mix, the only
time virCommandFree can reap a process is if someone did
virCommandRunAsync for a non-daemon and didn't stash the pid.

* src/util/command.h (virCommandAbort): New prototype.
* src/util/command.c (_virCommand): Add new field.
(virCommandRunAsync, virCommandWait): Track whether pid was used.
(virCommandFree): Reap child if caller did not request pid.
(virCommandAbort): New function.
* src/libvirt_private.syms (command.h): Export it.
* tests/commandtest.c (test19): New test.
2011-03-25 05:34:48 -06:00
Eric Blake
4e808602f1 command: don't mix RunAsync and daemons
It doesn't make sense to run a daemon without synchronously
waiting for the child process to reply whether the daemon has
been kicked off and pidfile written yet.

* src/util/command.c (VIR_EXEC_RUN_SYNC): New constant.
(virCommandRun): Set temporary flag.
(virCommandRunAsync): Use it to prevent async runs of intermediate
child when spawning asynchronous daemon grandchild.
2011-03-25 05:34:48 -06:00
Eric Blake
208a044a54 command: properly diagnose process exit via signal
Child processes don't always reach _exit(); if they die from a
signal, then any messages should still be accurate.  Most users
either expect a 0 status (thankfully, if status==0, then
WIFEXITED(status) is true and WEXITSTATUS(status)==0 for all
known platforms) or were filtering on WIFEXITED before printing
a status, but a few were missing this check.  Additionally,
nwfilter_ebiptables_driver was making an assumption that works
on Linux (where WEXITSTATUS shifts and WTERMSIG just masks)
but fails on other platforms (where WEXITSTATUS just masks and
WTERMSIG shifts).

* src/util/command.h (virCommandTranslateStatus): New helper.
* src/libvirt_private.syms (command.h): Export it.
* src/util/command.c (virCommandTranslateStatus): New function.
(virCommandWait): Use it to also diagnose status from signals.
* src/security/security_apparmor.c (load_profile): Likewise.
* src/storage/storage_backend.c
(virStorageBackendQEMUImgBackingFormat): Likewise.
* src/util/util.c (virExecDaemonize, virRunWithHook)
(virFileOperation, virDirCreate): Likewise.
* daemon/remote.c (remoteDispatchAuthPolkit): Likewise.
* src/nwfilter/nwfilter_ebiptables_driver.c (ebiptablesExecCLI):
Likewise.
2011-03-25 05:34:48 -06:00
Eric Blake
391c397e48 maint: prohibit access(,X_OK)
This simplifies several callers that were repeating checks already
guaranteed by util.c, and makes other callers more robust to now
reject directories.  remote_driver.c was over-strict - access(,R_OK)
is only needed to execute a script file; a binary only needs
access(,X_OK) (besides, it's unusual to see a file with x but not
r permissions, whether script or binary).

* cfg.mk (sc_prohibit_access_xok): New syntax-check rule.
(exclude_file_name_regexp--sc_prohibit_access_xok): Exempt one use.
* src/network/bridge_driver.c (networkStartRadvd): Fix offenders.
* src/qemu/qemu_capabilities.c (qemuCapsProbeMachineTypes)
(qemuCapsInitGuest, qemuCapsInit, qemuCapsExtractVersionInfo):
Likewise.
* src/remote/remote_driver.c (remoteFindDaemonPath): Likewise.
* src/uml/uml_driver.c (umlStartVMDaemon): Likewise.
* src/util/hooks.c (virHookCheck): Likewise.
2011-03-24 15:18:44 -06:00
Eric Blake
ee691d8433 command: reject pidfile on non-daemon
* src/util/command.c (virCommandRunAsync): Since virExec only
creates pidfiles for daemon, enforce this in virCommand.
2011-03-23 15:01:28 -06:00
Osier Yang
93e8b8778a util: Fix return value for virJSONValueFromString if it fails
Problem:
  "parser.head" is not NULL even if it's free'ed by "virJSONValueFree",
returning "parser.head" when "virJSONValueFromString" fails will cause
unexpected errors (libvirtd will crash sometimes), e.g.
  In function "qemuMonitorJSONArbitraryCommand":

        if (!(cmd = virJSONValueFromString(cmd_str)))
            goto cleanup;

        if (qemuMonitorJSONCommand(mon, cmd, &reply) < 0)
            goto cleanup;

        ......

     cleanup:
        virJSONValueFree(cmd);

  It will continues to send command to monitor even if "virJSONValueFromString"
is failed, and more worse, it trys to free "cmd" again.

  Crash example:
{"error":{"class":"QMPBadInputObject","desc":"Expected 'execute' in QMP input","data":{"expected":"execute"}}}
{"error":{"class":"QMPBadInputObject","desc":"Expected 'execute' in QMP input","data":{"expected":"execute"}}}
error: server closed connection:
error: unable to connect to '/var/run/libvirt/libvirt-sock', libvirtd may need to be started: Connection refused
error: failed to connect to the hypervisor

  This fix is to:
    1) return NULL for failure of "virJSONValueFromString",
    2) and it seems "virJSONValueFree" uses incorrect loop index for type
       of "VIR_JSON_TYPE_OBJECT", fix it together.

* src/util/json.c
2011-03-23 22:57:44 +08:00