[libvirt] [PATCHv7 3/4] libvirt/qemu - check address confliction before addition.

[Hu Tao]

On Fri, Mar 25, 2011 at 05:17:03PM +0900, KAMEZAWA Hiroyuki wrote:
> >From 638341bdf3eaac824e36d265e134608279750049 Mon Sep 17 00:00:00 2001
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> Date: Fri, 25 Mar 2011 17:10:58 +0900
> Subject: [PATCHv7 3/4] libvirt/qemu - check address confliction before addition.
> 
> qemuDomainAttachDevicePersistent() calls qemuDomainAssignPCIAddresses()
> and virDomainDefAddImplicitControllers() at the end of its call.
> 
> But PCI/Drive address confliction checks are
>  PCI - confliction will be found but error report is not verbose.
>  Drive - never done.
> 
> For example, you can add following (unusual) 2 devices without errors.
> 
> <disk type='file' device='disk'>
>    <driver name='qemu' type='raw'/>
>    <source file='/var/lib/libvirt/images/test3.img'/>
>    <target dev="sdx" bus='scsi'/>
>    <address type='drive' controller='0' bus='0' unit='0'/>
> </disk>
> 
> <disk type='file' device='disk'>
>    <driver name='qemu' type='raw'/>
>    <source file='/var/lib/libvirt/images/test3.img'/>
>    <target dev="sdy" bus='scsi'/>
>    <address type='drive' controller='0' bus='0' unit='0'/>
> </disk>
> 
> It's better to check drive address confliction before addition.
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> ---
>  src/conf/domain_conf.c   |   59 ++++++++++++++++++++++++++++++++++++++++++++++
>  src/conf/domain_conf.h   |    2 +
>  src/libvirt_private.syms |    1 +
>  src/qemu/qemu_driver.c   |    9 +++++++
>  4 files changed, 71 insertions(+), 0 deletions(-)
> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 3e3f342..4a54f62 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -1287,6 +1287,65 @@ void virDomainDefClearDeviceAliases(virDomainDefPtr def)
>      virDomainDeviceInfoIterate(def, virDomainDeviceInfoClearAlias, NULL);
>  }
>  
> +static int virDomainDeviceAddressMatch(virDomainDefPtr def ATTRIBUTE_UNUSED,
> +                                       virDomainDeviceInfoPtr info,
> +                                       void *opaque)
> +{
> +    virDomainDeviceInfoPtr checked = opaque;
> +    /* skip to check confliction of alias */
> +    if (info->type != checked->type)
> +            return 0;
> +    if (info->alias && checked->alias && strcmp(info->alias, checked->alias))

!STREQ instead of strcmp

> +            return -1;
> +    if (!memcmp(&info->addr, &checked->addr, sizeof(info->addr)))

Is it safe to memcmp an union like this? In the cases members of an
union are of different sizes, and we intent to memcmp an union member
that has a smaller size than the other members, then data in space
not used by the union member to be compared is also compared. This is
not a desired result.

> +            return -1;
> +    return 0;
> +}
> +

-- 
Thanks,
Hu Tao