[libvirt] [PATCH] conf: Drop restrictions on rng backend path

[Richard W.M. Jones]

On Wed, Apr 20, 2016 at 06:19:25PM -0400, Cole Robinson wrote:
> Currently we only allow /dev/random and /dev/hwrng as host input
> for <rng><backend model='random'/> device. This was added after
> various upstream discussions in commit 4932ef45
> 
> However this restriction has generated quite a few complaints over
> the years, so a new discussion was initiated:
> 
> http://www.redhat.com/archives/libvir-list/2016-April/msg00987.html
> 
> Several people suggested removing the restriction, and nobody really
> spoke up to defend it. So this patch drops the path restriction
> entirely
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1074464
> ---
>  docs/formatdomain.html.in                                     | 9 ++++-----
>  docs/schemas/domaincommon.rng                                 | 3 +--
>  src/conf/domain_conf.c                                        | 8 --------
>  tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args    | 2 +-
>  tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.xml     | 2 +-
>  tests/qemuxml2xmloutdata/qemuxml2xmlout-virtio-rng-random.xml | 2 +-
>  6 files changed, 8 insertions(+), 18 deletions(-)
> 
> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
> index 895114b..132b261 100644
> --- a/docs/formatdomain.html.in
> +++ b/docs/formatdomain.html.in
> @@ -6231,8 +6231,7 @@ qemu-kvm -net nic,model=? /dev/null
>            <code>model</code> attribute. Supported source models are:
>          </p>
>          <ul>
> -          <li>'random' — /dev/random (default) or /dev/hwrng
> -            device as source (for now, no other sources are permitted)</li>
> +          <li>'random' — a character device backend</li>
>            <li>'egd' — a EGD protocol backend</li>
>          </ul>
>        </dd>
> @@ -6240,9 +6239,9 @@ qemu-kvm -net nic,model=? /dev/null
>        <dd>
>          <p>
>            This backend type expects a non-blocking character device as input.
> -          The only accepted paths are /dev/random and /dev/hwrng. The file
> -          name is specified as contents of the <code>backend</code> element.
> -          When no file name is specified the hypervisor default is used.
> +          The file name is specified as contents of the
> +          <code>backend</code> element. When no file name is specified the
> +          this defaults to /dev/random.
>          </p>
>        </dd>
>        <dt><code>backend model='egd'</code></dt>
> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
> index 3605afe..c91a3a9 100644
> --- a/docs/schemas/domaincommon.rng
> +++ b/docs/schemas/domaincommon.rng
> @@ -4691,8 +4691,7 @@
>              <value>random</value>
>            </attribute>
>            <choice>
> -            <value>/dev/random</value>
> -            <value>/dev/hwrng</value>
> +            <ref name='absFilePath'/>
>              <empty/>
>            </choice>
>          </group>
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 28248c8..f9cd69c 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -11512,14 +11512,6 @@ virDomainRNGDefParseXML(xmlNodePtr node,
>      switch ((virDomainRNGBackend) def->backend) {
>      case VIR_DOMAIN_RNG_BACKEND_RANDOM:
>          def->source.file = virXPathString("string(./backend)", ctxt);
> -        if (def->source.file &&
> -            STRNEQ(def->source.file, "/dev/random") &&
> -            STRNEQ(def->source.file, "/dev/hwrng")) {
> -            virReportError(VIR_ERR_XML_ERROR,
> -                           _("file '%s' is not a supported random source"),
> -                           def->source.file);
> -            goto error;
> -        }
>          break;
>  
>      case VIR_DOMAIN_RNG_BACKEND_EGD:
> diff --git a/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args b/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args
> index ba97c1e..5a4d47b 100644
> --- a/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args
> +++ b/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.args
> @@ -18,6 +18,6 @@ QEMU_AUDIO_DRV=none \
>  -boot c \
>  -usb \
>  -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3 \
> --object rng-random,id=objrng0,filename=/dev/hwrng \
> +-object rng-random,id=objrng0,filename=/dev/urandom \
>  -device virtio-rng-pci,rng=objrng0,id=rng0,max-bytes=123,period=1234,bus=pci.0,\
>  addr=0x4
> diff --git a/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.xml b/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.xml
> index 71bd21a..a6e91ff 100644
> --- a/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.xml
> +++ b/tests/qemuxml2argvdata/qemuxml2argv-virtio-rng-random.xml
> @@ -21,7 +21,7 @@
>      <memballoon model='virtio'/>
>      <rng model='virtio'>
>        <rate bytes='123' period='1234'/>
> -      <backend model='random'>/dev/hwrng</backend>
> +      <backend model='random'>/dev/urandom</backend>
>      </rng>
>    </devices>
>  </domain>
> diff --git a/tests/qemuxml2xmloutdata/qemuxml2xmlout-virtio-rng-random.xml b/tests/qemuxml2xmloutdata/qemuxml2xmlout-virtio-rng-random.xml
> index e8a0478..0bdefde 100644
> --- a/tests/qemuxml2xmloutdata/qemuxml2xmlout-virtio-rng-random.xml
> +++ b/tests/qemuxml2xmloutdata/qemuxml2xmlout-virtio-rng-random.xml
> @@ -25,7 +25,7 @@
>      </memballoon>
>      <rng model='virtio'>
>        <rate bytes='123' period='1234'/>
> -      <backend model='random'>/dev/hwrng</backend>
> +      <backend model='random'>/dev/urandom</backend>
>        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
>      </rng>
>    </devices>

ACK.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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