[PATCH 3/4] conf: Rework <tpm/> formatting

[Peter Krempa]

On Tue, Jan 04, 2022 at 09:14:29 +0100, Michal Privoznik wrote:
> The <tpm/> element formatting is handled in
> virDomainTPMDefFormat() which uses the "old style" - appending
> strings directly into the output buffer. With this, it's easy to
> get conditions that tell when an element has ended wrong. In this
> particular case, if both <encryption/> and <active_pcr_banks/>
> are to be formatted the current code puts a stray '>' into the
> output buffer, resulting in invalid XML.
> 
> Rewrite the function to use virXMLFormatElement() which is more
> clever.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=2016599#c15
> 
> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> ---
>  src/conf/domain_conf.c                       | 53 ++++++++------------
>  tests/qemuxml2argvdata/tpm-emulator-tpm2.xml |  1 -
>  2 files changed, 22 insertions(+), 32 deletions(-)
> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 716c6d2240..b8fef8586c 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -25481,63 +25481,54 @@ virDomainTPMDefFormat(virBuffer *buf,
>                        virDomainTPMDef *def,
>                        unsigned int flags)
>  {
> -    virBufferAsprintf(buf, "<tpm model='%s'>\n",
> +    g_auto(virBuffer) attrBuf = VIR_BUFFER_INITIALIZER;
> +    g_auto(virBuffer) childBuf = VIR_BUFFER_INIT_CHILD(buf);
> +    g_auto(virBuffer) backendAttrBuf = VIR_BUFFER_INITIALIZER;
> +    g_auto(virBuffer) backendBuf = VIR_BUFFER_INIT_CHILD(&childBuf);

Cannonically this would be 'backendChildBuf'.

[...]

Above code:
Reviewed-by: Peter Krempa <pkrempa at redhat.com>

> diff --git a/tests/qemuxml2argvdata/tpm-emulator-tpm2.xml b/tests/qemuxml2argvdata/tpm-emulator-tpm2.xml
> index 59dd68311f..79acde218b 100644
> --- a/tests/qemuxml2argvdata/tpm-emulator-tpm2.xml
> +++ b/tests/qemuxml2argvdata/tpm-emulator-tpm2.xml
> @@ -30,7 +30,6 @@
>      <tpm model='tpm-tis'>
>        <backend type='emulator' version='2.0'>
>          <encryption secret='b4a117f1-8af2-44a4-91b8-7f0d2d4d68a3'/>
> -      >
>          <active_pcr_banks>
>            <sha256/>
>            <sha512/>
> -- 
> 2.34.1
>