[libvirt] [PATCHv2 5/5] qemu: error out on missing machine type in configs

[John Ferlan]

On 02/25/2016 10:40 AM, Ján Tomko wrote:
> Commit f1a89a8 allowed parsing configs from /etc/libvirt
> without validating the emulator capabilities.
> 
> Check for the presence of a machine type in the qemu driver's
> post parse function instead of crashing.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1267256
> ---
>  src/qemu/qemu_domain.c                             |  6 +++++
>  .../qemuxml2argv-missing-machine.xml               | 30 ++++++++++++++++++++++
>  tests/qemuxml2argvtest.c                           |  8 ++++++
>  3 files changed, 44 insertions(+)
>  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-missing-machine.xml
> 
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index c56f9f1..8c96a33 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -1307,6 +1307,12 @@ qemuDomainDefPostParse(virDomainDefPtr def,
>          return ret;
>      }
>  
> +    if (!def->os.machine) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("Missing machine type"));

A "nit" of sorts...  Sometimes we start error messages with Capital
letters and sometimes we don't... I guess I've trained my fingers to go
with lower case letters (although it really messes with my eyes/brain).
Since a majority in qemu_domain go with lower case, could we take that
path here too.

But really what I'd like to point out - would it be possible to add
"def->name" to the error message to indicate which domain had the issue.

When it happened to me all I got were two messages during startup - I
had to generate a local patch which added the def->name to the output to
figure out which of my domains had the issue.

This actually is a much bigger problem overall... We have a *lot* of
messages spewed in domain_conf.c and perhaps a couple that spit out
*which* domain.  Now if I'm defining/creating a single domain, it's easy
to figure out.  Figuring it out which domain had an issue during
libvirtd start/restart/reload is a problem of magnitude! I have to
figure out who's missing ;-)

Tks -

John
> +        return ret;
> +    }
> +
>      /* check for emulator and create a default one if needed */
>      if (!def->emulator &&
>          !(def->emulator = virDomainDefGetDefaultEmulator(def, caps)))
> diff --git a/tests/qemuxml2argvdata/qemuxml2argv-missing-machine.xml b/tests/qemuxml2argvdata/qemuxml2argv-missing-machine.xml
> new file mode 100644
> index 0000000..12f7d2f
> --- /dev/null
> +++ b/tests/qemuxml2argvdata/qemuxml2argv-missing-machine.xml
> @@ -0,0 +1,30 @@
> +<domain type='qemu'>
> +  <name>QEMUGuest1</name>
> +  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
> +  <title>A description of the test machine.</title>
> +  <memory unit='KiB'>219100</memory>
> +  <currentMemory unit='KiB'>219100</currentMemory>
> +  <vcpu placement='static' cpuset='1'>1</vcpu>
> +  <os>
> +    <type arch='i686'>hvm</type>
> +    <boot dev='hd'/>
> +  </os>
> +  <clock offset='utc'/>
> +  <on_poweroff>destroy</on_poweroff>
> +  <on_reboot>restart</on_reboot>
> +  <on_crash>destroy</on_crash>
> +  <devices>
> +    <emulator>/usr/bin/qemu</emulator>
> +    <disk type='block' device='disk'>
> +      <source dev='/dev/HostVG/QEMUGuest1'/>
> +      <target dev='hda' bus='ide'/>
> +      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
> +    </disk>
> +    <controller type='usb' index='0'/>
> +    <controller type='ide' index='0'/>
> +    <controller type='pci' index='0' model='pci-root'/>
> +    <input type='mouse' bus='ps2'/>
> +    <input type='keyboard' bus='ps2'/>
> +    <memballoon model='virtio'/>
> +  </devices>
> +</domain>
> diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
> index 517f996..ff12077 100644
> --- a/tests/qemuxml2argvtest.c
> +++ b/tests/qemuxml2argvtest.c
> @@ -571,6 +571,10 @@ mymain(void)
>                   FLAG_EXPECT_PARSE_ERROR | FLAG_EXPECT_ERROR,           \
>                   0, __VA_ARGS__)
>  
> +# define DO_TEST_PARSE_FLAGS_ERROR(name, parseFlags, ...)               \
> +    DO_TEST_FULL(name, NULL, -1,                                        \
> +                 FLAG_EXPECT_PARSE_ERROR | FLAG_EXPECT_ERROR,           \
> +                 parseFlags, __VA_ARGS__)
>  
>  # define DO_TEST_LINUX(name, ...)                                       \
>      DO_TEST_LINUX_FULL(name, NULL, -1, 0, 0, __VA_ARGS__)
> @@ -1868,6 +1872,10 @@ mymain(void)
>      DO_TEST("ppc64-usb-controller-legacy",
>              QEMU_CAPS_PIIX3_USB_UHCI);
>  
> +    DO_TEST_PARSE_FLAGS_ERROR("missing-machine",
> +                              VIR_DOMAIN_DEF_PARSE_SKIP_OSTYPE_CHECKS,
> +                              NONE);
> +
>      qemuTestDriverFree(&driver);
>  
>      return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
>