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Re: [libvirt] [PATCH] qemu: pass the information when disks are read-only



On Mon, Mar 15, 2010 at 03:41:34PM +0000, Daniel P. Berrange wrote:
> On Thu, Mar 11, 2010 at 06:14:01PM +0100, Daniel Veillard wrote:
> > The problem is that even when the user indicates that a drive has to be
> > opened as read-only (for example a cd-rom) qemu didn't get the
> > information and tried to open read-write. This could get really nasty
> > in case SELinux is monitoring that no read-write access is attempted:
> > 
> >   https://bugzilla.redhat.com/show_bug.cgi?id=536760
> > 
> > Patch is relatively simple and based on teh assumption that if the
> > -device qemu options are allowed then qemu also knows about the
> > readonly option (this was added to the help string quite later so
> > we should not rely on that in this case).
> > 
> > * src/qemu/qemu_conf.c: add the ",readonly=on" for read-only disks
> >   and also parse it back in qemuParseCommandLineDisk()
> > * tests/qemuxml2argvtest.c
> >   tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.args
> >   tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml:
> >   add a specific regression test
> > 
> > diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
> > index 40ca221..fb23c52 100644
> > --- a/src/qemu/qemu_conf.c
> > +++ b/src/qemu/qemu_conf.c
> > @@ -2398,6 +2398,9 @@ qemuBuildDriveStr(virDomainDiskDefPtr disk,
> >      if (bootable &&
> >          disk->device == VIR_DOMAIN_DISK_DEVICE_DISK)
> >          virBufferAddLit(&opt, ",boot=on");
> > +    if (disk->readonly &&
> > +        qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE)
> > +        virBufferAddLit(&opt, ",readonly=on");
> >      if (disk->driverType &&
> >          disk->type != VIR_DOMAIN_DISK_TYPE_DIR &&
> >          qemuCmdFlags & QEMUD_CMD_FLAG_DRIVE_FORMAT)
> > @@ -4694,6 +4697,9 @@ qemuParseCommandLineDisk(const char *val,
> >                                  _("cannot parse drive unit '%s'"), val);
> >                  goto cleanup;
> >              }
> > +        } else if (STREQ(keywords[i], "readonly")) {
> > +            if ((values[i] == NULL) || STREQ(values[i], "on"))
> > +                def->readonly = 1;
> >          }
> >      }
> >  
> > diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.args b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.args
> > new file mode 100644
> > index 0000000..fbc3226
> > --- /dev/null
> > +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.args
> > @@ -0,0 +1 @@
> > +LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M pc -m 214 -smp 1 -nographic -nodefaults -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -drive file=/dev/HostVG/QEMUGuest1,if=none,id=drive-ide0-0-0 -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -drive file=/dev/sr0,if=none,media=cdrom,id=drive-ide0-1-0,readonly=on -device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -usb -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3
> > diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml
> > new file mode 100644
> > index 0000000..39c3a1c
> > --- /dev/null
> > +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml
> > @@ -0,0 +1,30 @@
> > +<domain type='qemu'>
> > +  <name>QEMUGuest1</name>
> > +  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
> > +  <memory>219200</memory>
> > +  <currentMemory>219200</currentMemory>
> > +  <vcpu>1</vcpu>
> > +  <os>
> > +    <type arch='i686' machine='pc'>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' unit='0'/>
> > +    </disk>
> > +    <disk type='block' device='cdrom'>
> > +       <source dev='/dev/sr0'/>
> > +       <target dev='hdc' bus='ide'/>
> > +       <readonly/>
> > +       <address type='drive' controller='0' bus='1' unit='0'/>
> > +    </disk>
> > +    <controller type='ide' index='0'/>
> > +  </devices>
> > +</domain>
> > diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
> > index 4ca946a..e3762c9 100644
> > --- a/tests/qemuxml2argvtest.c
> > +++ b/tests/qemuxml2argvtest.c
> > @@ -249,6 +249,8 @@ mymain(int argc, char **argv)
> >              QEMUD_CMD_FLAG_DRIVE_BOOT | QEMUD_CMD_FLAG_DRIVE_FORMAT);
> >      DO_TEST("disk-drive-fat", QEMUD_CMD_FLAG_DRIVE |
> >              QEMUD_CMD_FLAG_DRIVE_BOOT | QEMUD_CMD_FLAG_DRIVE_FORMAT);
> > +    DO_TEST("disk-drive-readonly-disk", QEMUD_CMD_FLAG_DRIVE |
> > +            QEMUD_CMD_FLAG_DEVICE);
> >      DO_TEST("disk-drive-fmt-qcow", QEMUD_CMD_FLAG_DRIVE |
> >              QEMUD_CMD_FLAG_DRIVE_BOOT | QEMUD_CMD_FLAG_DRIVE_FORMAT);
> >      DO_TEST("disk-drive-shared", QEMUD_CMD_FLAG_DRIVE |
> > 
> 
> ACK, good to finally have this done

  Okay, pushed, thanks !

Daniel

-- 
Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel veillard com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/


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