Eric Blake [Fri, 8 Jul 2011 16:54:02 +0000 (10:54 -0600)]
build: also check qemu_protocol for on-the-wire stability
Since we are going to add some libvirt-qemu.so entry points in
0.9.4, we might as well start checking for RPC stability, just
as for libvirt.so.
* src/Makefile.am (PROTOCOL_STRUCTS): New variable.
(remote_protocol-structs): Rename...
(%_protocol-structs): ...and make more generic.
* src/qemu_protocol-structs: New file.
Eric Blake [Mon, 11 Jul 2011 23:22:20 +0000 (17:22 -0600)]
build: avoid requiring -lm
log2() is heavy when ffs() can do the same thing. But ffs()
requires gnulib support for mingw.
This patch solves this linker error on Fedora 14.
/usr/bin/ld: libvirt_lxc-domain_conf.o: undefined reference to symbol 'log2@@GLIBC_2.2.5'
/usr/bin/ld: note: 'log2@@GLIBC_2.2.5' is defined in DSO /lib64/libm.so.6 so try adding it to the linker command line
/lib64/libm.so.6: could not read symbols: Invalid operation
collect2: ld returned 1 exit status
* .gnulib: Update to latest, for ffs.
* bootstrap.conf (gnulib_modules): Import ffs.
* src/conf/domain_conf.c (virDomainDefParseXML): Use ffs instead
of log2.
Reported by Dave Allan.
The drivers were accepting domain configs without checking if those
were actually meant for them. For example the LXC driver happily
accepts configs with type QEMU.
Add a check for the expected domain types to the virDomainDefParse*
functions.
Alex Jia [Mon, 11 Jul 2011 05:14:45 +0000 (13:14 +0800)]
remote: Fix memory leak
Detected in valgrind run:
==9184== 1 bytes in 1 blocks are definitely lost in loss record 1 of 19
==9184== at 0x4A04A28: calloc (vg_replace_malloc.c:467)
==9184== by 0x3073715F78: xdr_array (xdr_array.c:97)
==9184== by 0x4CF97C9: xdr_remote_domain_get_security_label_ret (remote_protocol.c:1696)
==9184== by 0x4D08741: virNetMessageDecodePayload (virnetmessage.c:286)
==9184== by 0x4D00F78: virNetClientProgramCall (virnetclientprogram.c:318)
==9184== by 0x4CE3887: call (remote_driver.c:3933)
==9184== by 0x4CF71C6: remoteDomainGetSecurityLabel (remote_driver.c:1580)
==9184== by 0x4CCA480: virDomainGetSecurityLabel (libvirt.c:7340)
==9184== by 0x41993A: cmdDominfo (virsh.c:2414)
==9184== by 0x411E92: vshCommandRun (virsh.c:12730)
==9184== by 0x4211ED: main (virsh.c:14076)
==9184==
==9184== 2 bytes in 1 blocks are definitely lost in loss record 2 of 19
==9184== at 0x4A04A28: calloc (vg_replace_malloc.c:467)
==9184== by 0x3073715F78: xdr_array (xdr_array.c:97)
==9184== by 0x4CF974F: xdr_remote_node_get_security_model_ret (remote_protocol.c:1713)
==9184== by 0x4D08741: virNetMessageDecodePayload (virnetmessage.c:286)
==9184== by 0x4D00F78: virNetClientProgramCall (virnetclientprogram.c:318)
==9184== by 0x4CE3887: call (remote_driver.c:3933)
==9184== by 0x4CF6F96: remoteNodeGetSecurityModel (remote_driver.c:1648)
==9184== by 0x4CBF799: virNodeGetSecurityModel (libvirt.c:7382)
==9184== by 0x4197D7: cmdDominfo (virsh.c:2394)
==9184== by 0x411E92: vshCommandRun (virsh.c:12730)
==9184== by 0x4211ED: main (virsh.c:14076)
==9184==
==9184== 8 bytes in 1 blocks are definitely lost in loss record 3 of 19
==9184== at 0x4A04A28: calloc (vg_replace_malloc.c:467)
==9184== by 0x3073715F78: xdr_array (xdr_array.c:97)
==9184== by 0x4CF9729: xdr_remote_node_get_security_model_ret (remote_protocol.c:1710)
==9184== by 0x4D08741: virNetMessageDecodePayload (virnetmessage.c:286)
==9184== by 0x4D00F78: virNetClientProgramCall (virnetclientprogram.c:318)
==9184== by 0x4CE3887: call (remote_driver.c:3933)
==9184== by 0x4CF6F96: remoteNodeGetSecurityModel (remote_driver.c:1648)
==9184== by 0x4CBF799: virNodeGetSecurityModel (libvirt.c:7382)
==9184== by 0x4197D7: cmdDominfo (virsh.c:2394)
==9184== by 0x411E92: vshCommandRun (virsh.c:12730)
==9184== by 0x4211ED: main (virsh.c:14076)
==9184==
==9184== LEAK SUMMARY:
==9184== definitely lost: 11 bytes in 3 blocks
* src/remote/remote_driver.c: Avoid leak on remoteDomainGetSecurityLabel
and remoteNodeGetSecurityModel.
Eric Blake [Mon, 11 Jul 2011 15:19:11 +0000 (09:19 -0600)]
tests: simplify formatting
The shell version would output 40 extra spaces for a test with
a multiple of 40 sub-tests, and the C version can use the same
printf optimization for avoiding a loop over single space output
as the shell version.
* tests/testutils.c (virtTestMain): Avoid loop for alignment.
* tests/test-lib.sh: Fix formatting when counter is multiple of 40.
Jim Fehlig [Thu, 7 Jul 2011 01:17:16 +0000 (19:17 -0600)]
Do not drop kernel cmdline for xen pv domains
Kernel cmdline args can be passed to xen pv domains even when a
bootloader is specified. The current config-to-sxpr mapping
ignores cmdline when bootloader is present.
Since the xend sub-driver is used with many xen toolstack versions,
this patch takes conservative approach of adding an else block to
existing !def->os.bootloader, and only appends sxpr if def->os.cmdline
is non-NULL.
V2: Fix existing testcase broken by this patch and add new testcases
If virDomainSaveConfig() failed, we will return NULL to source,
and the vm is still available to restart during confirm() step in
v3 protocol. So we should kill it off in qemuMigrationFinish().
In v2 protocol, we should not set vm to NULL, because we hold
a reference of vm and should unrefernce it.
This patch creates new <bios> element which, at this time has only the
attribute useserial='yes|no'. This attribute allow users to use
Serial Graphics Adapter and see BIOS messages from the very first moment
domain boots up. Therefore, users can choose boot medium, set PXE, etc.
tests: Improve output of tests that decide to skip at runtime
Don't print OK/FAIL for tests that decide to be skipped after
calling virtTestMain. Delay printing of the indentation before
the first test until we know that the test didn't decide to be
skipped.
The current logic tries to count from 1 to 40 and ignores paddings
of 0 and 1 to 40. This doesn't work for counter + 1 mod 40 == 0
like here for counter value 159
It is common for the $HOME/.libvirt/libvirtd.conf file to not
exist. Treat this situation as non-fatal since we can carry
on with our default settings just fine.
* daemon/libvirtd.c: Treat ENOENT as non-fatal when loading
config
The dispatch for the CLOSE RPC call was invoking the method
virNetServerClientClose(). This caused the client connection
to be immediately terminated. This meant the reply to the
final RPC message was never sent. Prior to the RPC rewrite
we merely flagged the connection for closing, and actually
closed it when the next RPC call dispatch had completed.
* daemon/remote.c: Flag connection for a delayed close
* daemon/stream.c: Update to use new API for closing
failed connection
* src/rpc/virnetserverclient.c, src/rpc/virnetserverclient.h:
Add support for a delayed connection close. Rename the
virNetServerClientMarkClose method to virNetServerClientImmediateClose
to clarify its semantics
Fix leak of remote driver if final 'CLOSE' RPC call fails
When closing a remote connection we issue a (fairly pointless)
'CLOSE' RPC call to the daemon. If this fails we skip all the
cleanup of private data, but the virConnectPtr object still
gets released as normal. This causes a memory leak. Since the
CLOSE RPC call is pretty pointless, just carry on freeing the
remote driver if it fails.
* src/remote/remote_driver.c: Ignore failure to issue CLOSE
RPC call
Fix release of outgoing stream confirmation/abort message
When sending back the final OK or ERROR message on completion
of a stream, we were not decrementing the 'nrequests' tracker
on the client. With the default requests limit of '5', this
meant once a client had created 5 streams, they are unable to
process any further RPC calls. There was also a bug when
handling an error from decoding a message length header, which
meant a client connection would not immediately be closed.
* src/rpc/virnetserverclient.c: Fix release of request after
stream completion & mark client for close on error
In one exit path we forgot to free the virNetMessage object causing
a large memory leak for streams which send a lot of data. Some other
paths were calling VIR_FREE directly instead of virNetMessageFree
although this was (currently) harmless.
* src/rpc/virnetclientstream.c: Fix leak of msg object
* src/rpc/virnetclientprogram.c: Call virNetMessageFree instead
of VIR_FREE
Fix potential crash in libvirtd with active streams
If a client disconnects while it has a stream active, there is
a race condition which could see libvirtd crash. This is because
the client struct may be freed before the last stream event has
triggered. This is trivially solved by holding an extra reference
on the client for the stream callbak
* daemon/stream.c: Acquire reference on client when adding the
stream callback
Fix mistaken order of server cert/key parameters in constructor
The virNetTLSContextNew was being passed key/cert parameters in
the wrong order. This wasn't immediately visible because if
virNetTLSContextNewPath was used, a second bug reversed the order
of those parameters again.
Only if the paths were manually specified in /etc/libvirt/libvirtd.conf
did the bug appear
* src/rpc/virnettlscontext.c: Fix order of params passed to
virNetTLSContextNew
Michal Privoznik [Thu, 26 May 2011 14:15:54 +0000 (16:15 +0200)]
graphics: add support for action_if_connected in qemu
This option accepts 3 values:
-keep, to keep current client connected (Spice+VNC)
-disconnect, to disconnect client (Spice)
-fail, to fail setting password if there is a client connected (Spice)
util: Don't try to fchown files opened as non-root
When virFileOpenAs is called with VIR_FILE_OPEN_AS_UID flag and uid/gid
different from root/root while libvirtd is running as root, we fork a
new child, change its effective UID/GID to uid/gid and run
virFileOpenAsNoFork. It doesn't make any sense to fchown() the opened
file in this case since we already know that uid/gid can access the file
when open succeeds and one of the following situations may happen:
- the file is already owned by uid/gid and we skip fchown even before
this patch
- the file is owned by uid but not gid because it was created in a
directory with SETGID set, in which case it is desirable not to change
the group
- the file may be owned by a completely different user and/or group
because it was created on a root-squashed or even all-squashed NFS
filesystem, in which case fchown would most likely fail anyway
Jim Fehlig [Thu, 7 Jul 2011 21:53:41 +0000 (15:53 -0600)]
Skip some xen tests if xend is not running
Currently, the xen statstest and reconnect tests are only compiled
if xend is running. Compile them unconditionally if xen headers
are present, but skip the tests at runtime if xend is not running.
Eric Blake [Wed, 6 Jul 2011 19:55:47 +0000 (13:55 -0600)]
public API: prefer unsigned int for flags
Most APIs use 'unsigned int flags'; but a few stragglers were using
a signed value. In particular, the vir*GetXMLDesc APIs were
split-brain, with inconsistent choice of types. Although it is
an API break to use 'int' instead of 'unsigned int', it is ABI
compatible (pre-compiled apps will have no difference in behavior),
and generally apps can be recompiled without any issue (only rare
apps that compiled with extremely high warning levels, or which
pass libvirt API around as typed function pointers, would have to
make any code changes to deal with the change).
The migrate APIs use 'unsigned long flags', which can't be changed,
due to ABI constraints.
This patch intentionally touches only the public API, to prove the
claim that most existing code (including driver callbacks and virsh)
still compiles just fine in spite of the type change.
* include/libvirt/libvirt.h.in (virConnectOpenAuth)
(virDomainCoreDump, virDomainGetXMLDesc, virNetworkGetXMLDesc)
(virNWFilterGetXMLDesc): Use unsigned int for flags.
(virDomainHasCurrentSnapshot): Use consistent spelling.
* src/libvirt.c (virConnectOpenAuth, virDomainCoreDump)
(virDomainGetXMLDesc, virNetworkGetXMLDesc)
(virNWFilterGetXMLDesc, do_open): Update accordingly.
Eric Blake [Thu, 30 Jun 2011 17:57:42 +0000 (11:57 -0600)]
build: fix virBufferVasprintf on mingw
Gnulib documents that mingw vsnprintf is broken (it returns -1
on out-of-space, instead of the count of what would have been
printed); but while we were using the snprintf wrapper, we had
not yet been using the vsnprintf wrapper.
Meanwhile, mingw (but not mingw64) has a replacement snprintf
that fixes return values, but still lacks %1$s support; so in
that case, gnulib didn't replace snprintf, but libintl then
went ahead and installed a version that supported %1$s but not
return values. Gnulib has since been fixed to guarantee that
the snprintf module will always guarantee the constraints needed
by libintl.
Also, we want to guarantee that strdup sets errno on failure.
* .gnulib: Update to latest, for vsnprintf fix.
* bootstrap.conf (gnulib_modules): Add vsnprintf, strdup-posix.
Reported by Matthias Bolte.
Eric Blake [Wed, 29 Jun 2011 17:47:08 +0000 (11:47 -0600)]
util: add virTrimSpaces
The next patch wants to adjust an end pointer to trim trailing
spaces but without modifying the underlying string, but a more
generally useful ability to trim trailing spaces in place is
also worth providing.
* src/util/util.h (virTrimSpaces, virSkipSpacesBackwards): New
prototypes.
* src/util/util.c (virTrimSpaces, virSkipSpacesBackwards): New
functions.
* src/libvirt_private.syms (util.h): Export new functions.
Inspired by a patch by Minoru Usui.
Eric Blake [Wed, 6 Jul 2011 19:49:28 +0000 (13:49 -0600)]
docs: minor whitespace cleanups
No change in wording. One spacing change in a <pre>, noticed because
of odd XML formatting online; the rest is in free-flowing text to
make it easier to see nesting levels in the document.
* docs/formatdomain.html.in: Adjust spacing. Break long lines.
Fix default value of security label 'relabel' attribute
When no <seclabel> is present in the XML, the virDomainSeclabelDef
struct is left as all zeros. Unfortunately, this means it gets setup
as type=dynamic, with relabel=no, which is an illegal combination.
Change the 'bool relabel' attribute in virDomainSeclabelDef to
the inverse 'bool norelabel' so that the default initialization
is sensible
* src/conf/domain_conf.c, src/conf/domain_conf.h,
src/security/security_apparmor.c, src/security/security_selinux.c:
Replace 'relabel' with 'norelabel'
Some callers expected virFileMakePath to set errno, some expected
it to return an errno value. Unify this to return 0 on success and
-1 on error. Set errno to report detailed error information.
Also optimize virFileMakePath if stat fails with an errno different
from ENOENT.
Laine Stump [Sun, 26 Jun 2011 09:13:10 +0000 (05:13 -0400)]
xml: create an RNG file for common types and move some definitions there
domain.rng, network.rng, and interface.rng already use a few of the
same types (or in some cases *should* but don't), and an upcoming code
change will have them sharing even more. To prepare for that, this
patch takes those common data type definitions and moves them into
basictypes.rng.
This may break some rule about the need to RNG files to be autonomous
or something, but I saw that storageencryption.rng is used in this
way, so I figured it must not be completely against the law...
Laine Stump [Sat, 2 Jul 2011 04:53:06 +0000 (00:53 -0400)]
qemu: check flags in qemuDomainGetXMLDesc
Although most functions with flags check to verify no application is
passing in flag bits that are currently undefined, for some reason
this function wasn't.
Laine Stump [Mon, 4 Jul 2011 19:06:07 +0000 (15:06 -0400)]
conf: fix domain parse flags
* Change all flags args from int to unsigned int
* Allow passing flags in virDomainObjParseFile (and propogate those
flags all the way down the call chain). Previously the flags were
hardcoded (to VIR_DOMAIN_XML_INTERNAL_STATUS) several layers down
the chain. Pass that value in at the one place that is currently
calling virDomainObjParseFile.
qemu: Fix virFileMakePath error handling in snapshot creation
virFileMakePath returns an errno value on error, that will never
be negative. An virFileMakePath error would have been ignored here,
instead of being reported correctly.
* docs/schemas/domain.rng: Add relabel attribute
* src/conf/domain_conf.c, src/conf/domain_conf.h: Parse
the 'relabel' attribute
* src/qemu/qemu_process.c: Unconditionally clear out the
'imagelabel' attribute
* src/security/security_apparmor.c: Skip based on 'relabel'
attribute instead of label type
* src/security/security_selinux.c: Skip based on 'relabel'
attribute instead of label type and fill in <imagelabel>
attribute if relabel is enabled.
Allow a base label to be specified in dynamic labelling mode
Normally the dynamic labelling mode will always use a base
label of 'svirt_t' for VMs. Introduce a <baselabel> field
in the <seclabel> XML to allow this base label to be changed
* docs/schemas/domain.rng: Add <baselabel>
* src/conf/domain_conf.c, src/conf/domain_conf.h: Parsing
of base label
* src/qemu/qemu_process.c: Don't reset 'model' attribute if
a base label is specified
* src/security/security_apparmor.c: Refuse to support base label
* src/security/security_selinux.c: Use 'baselabel' when generating
label, if available
Eric Blake [Mon, 4 Jul 2011 02:30:43 +0000 (10:30 +0800)]
qemu: avoid null deref on low memory
Detected by Coverity. qemuDomainEventQueue requires a non-NULL
pointer; most callers silently drop the event if we encountered
and OOM situation trying to create the event.
* src/qemu/qemu_migration.c (qemuMigrationFinish): Check for OOM.
Eric Blake [Mon, 4 Jul 2011 02:26:05 +0000 (10:26 +0800)]
rpc: silence coverity warning
Coverity noted that 4 out of 5 calls to virNetClientStreamRaiseError
checked the return value. This case expects a particular value, so
warn if our expectations went wrong due to some bug elsewhere.
* src/rpc/virnetclient.c (virNetClientCallDispatchStream): Warn on
unexpected scenario.
Eric Blake [Mon, 4 Jul 2011 02:23:46 +0000 (10:23 +0800)]
qemu: silence coverity warnings
Coverity warns if the majority of callers check a function for
errors, but a few don't; but in qemu_audit and qemu_domain, the
choice to not check for failures was safe. In qemu_command, the
failure to generate a uuid can only occur on a bad pointer.
* src/qemu/qemu_audit.c (qemuAuditCgroup): Ignore failure to get
cgroup controller.
* src/qemu/qemu_domain.c (qemuDomainObjEnterMonitor)
(qemuDomainObjEnterMonitorWithDriver): Ignore failure to get
timestamp.
* src/qemu/qemu_command.c (qemuParseCommandLine): Check for error.
Eric Blake [Mon, 4 Jul 2011 01:45:21 +0000 (09:45 +0800)]
rpc: fix logic bug
Spotted by Coverity. If we don't update tmp each time through
the loop, then if the filter being removed was not the head of
the list, we accidentally lose all filters prior to the one we
wanted to remove.
Eric Blake [Fri, 1 Jul 2011 13:23:02 +0000 (07:23 -0600)]
util: choose whether to require micro in version strings
To avoid regressions, we let callers specify whether to require a
minor and micro version. Callers that were parsing uname() output
benefit from defaulting to 0, whereas callers that were parsing
version strings from other sources should not change in behavior.
* src/util/util.c (virParseVersionString): Allow caller to choose
whether to fail if minor or micro is missing.
* src/util/util.h (virParseVersionString): Update signature.
* src/esx/esx_driver.c (esxGetVersion): Update callers.
* src/lxc/lxc_driver.c (lxcVersion): Likewise.
* src/openvz/openvz_conf.c (openvzExtractVersionInfo): Likewise.
* src/uml/uml_driver.c (umlGetVersion): Likewise.
* src/vbox/vbox_MSCOMGlue.c (vboxLookupVersionInRegistry):
Likewise.
* src/vbox/vbox_tmpl.c (vboxExtractVersion): Likewise.
* src/vmware/vmware_conf.c (vmwareExtractVersion): Likewise.
* src/xenapi/xenapi_driver.c (xenapiGetVersion): Likewise.
Reported by Matthias Bolte.
Eric Blake [Tue, 31 May 2011 22:15:28 +0000 (16:15 -0600)]
build: consistently use CFLAGS
According to the automake manual, CPPFLAGS (aka INCLUDES, as spelled
in automake 1.9.6) should only include -I, -D, and -U directives; more
generic directives like -Wall belong in CFLAGS since they affect more
phases of the build process. Therefore, we should be sticking CFLAGS
additions into a CFLAGS container, not a CPPFLAGS container.
* src/Makefile.am (libvirt_driver_vmware_la_CFLAGS): Use AM_CFLAGS.
(INCLUDES): Move CFLAGS items...
(AM_CFLAGS): ...to their proper location.
* python/Makefile.am (INCLUDES, AM_CFLAGS): Likewise.
* tests/Makefile.am (INCLUDES, AM_CFLAGS): Likewise.
(commandtest_CFLAGS, commandhelper_CFLAGS)
(virnetmessagetest_CFLAGS, virnetsockettest_CFLAGS): Use AM_CFLAGS.
Scott Moser [Fri, 1 Jul 2011 10:40:21 +0000 (06:40 -0400)]
fix virParseVersionString with linux 3.0
linux 3.0 has no micro version number, and that is causing problems
for virParseVersionString. The patch below should allow for:
major
major.minor
major.minor.micro
If major or minor are not present they just default to zero.
We found this in Ubuntu (https://bugs.launchpad.net/bugs/802977)
Eric Blake [Tue, 28 Jun 2011 15:50:11 +0000 (09:50 -0600)]
build: allow 'make syntax-check' on fresh checkout
For good or for bad, I did a fresh checkout, ./autogen.sh, then
'configure', then 'make syntax-check', and was surprised that it
failed. Running 'make' before 'make syntax-check' cleaned up the
issue, but this patch makes it work up front.
Eric Blake [Wed, 29 Jun 2011 22:11:30 +0000 (16:11 -0600)]
build: avoid double-close bug with pipe2
Based on Coverity's finding on the previous patch, I audited
gnulib's pipe2 code and found that we had the potential for
a subtle double-close bug, unless gnulib guarantees that the
contents of the fd array are unchanged on pipe2() failure.
Eric Blake [Wed, 29 Jun 2011 18:28:57 +0000 (12:28 -0600)]
rpc: avoid freeing uninitialized variable
Detected by Coverity. Both are instances of bad things happening
if pipe2 fails; the virNetClientNew failure could free garbage,
and virNetSocketNewConnectCommand could close random fds.
Note: POSIX doesn't guarantee the contents of fd[0] and fd[1]
after pipe failure: http://austingroupbugs.net/view.php?id=467
We may need to introduce a virPipe2 wrapper that guarantees
that on pipe failure, the fds are explicitly set to -1, rather
than our current state of assuming the fds are unchanged from
their value prior to the failed pipe call.
Eric Blake [Wed, 29 Jun 2011 17:58:36 +0000 (11:58 -0600)]
virsh: avoid integer overflow
Detected by Coverity. info.nrVirtCpu is unsigned short, but if
cpumaplen is int, then the product of the two in vshMalloc risks
unintended sign extension. cmdVcpuinfo had already solved this
by using size_t cpumaplen.
Fix stream procedure number for virDomainMigratePrepareTunnel3
The virDomainMigratePrepareTunnel3 impl in the remote driver
was using the procedure number for the virDomainMigratePrepareTunnel
method. This doesn't work out so well, because it makes the server
ignore & drop all stream packets
* src/remote/remote_driver.c: Fix procedure for PrepareTunnel3
Send back an error if we get unexpected stream control message
We ignore any stream data packets which come in for streams which
are not registered, since these packets are async and do not have
a reply. If we get a stream control packet though we must send back
an actual error, otherwise a (broken) client may hang forever
making it hard to diagnose the client bug.
* src/rpc/virnetserverprogram.c: Send back error for unexpected
stream control messages
Fix release of virNetMessagePtr instances in streams processing
If a message packet for a invalid stream is received it is just
free'd. This is not good because it doesn't let the client RPC
request counter decrement. If a stream is shutdown with pending
packets the message also isn't released properly because of an
incorrect header type
* daemon/stream.c: Fix message header type
* src/rpc/virnetserverprogram.c: Send dummy reply instead of
free'ing ignored stream message
While investigating some memory leaks it was unclear whether the
JSON code correctly free'd all memory during parsing. Add a test
case which can be run under valgrind to clearly demonstrate that
the parser is leak free.
* tests/Makefile.am: Add 'jsontest'
* tests/jsontest.c: A few simple JSON parsing tests