[libvirt] [PATCH 04/11] qemu_security: Kill code duplication

[Peter Krempa]

On Wed, Feb 08, 2017 at 15:33:48 +0100, Michal Privoznik wrote:
> On 02/08/2017 02:59 PM, Martin Kletzander wrote:
> > On Wed, Feb 08, 2017 at 02:37:48PM +0100, Michal Privoznik wrote:
> >> On 02/08/2017 01:43 PM, Peter Krempa wrote:
> >>> On Wed, Feb 08, 2017 at 13:37:48 +0100, Michal Privoznik wrote:
> >>>> On 02/08/2017 01:23 PM, Peter Krempa wrote:

[...]

> 
> This doesn't solve the syntax-check problem. But whatever, I will go
> with this and just drop the syntax-check patch. We have plenty of
> arguments for using macros here but since some don't like it I'm not
> going to push it. Lets just hope that we will take care to use
> qemuSecurity* wrappers instead of calling virSecurity APIs directly.
> Honestly, I don't care that much.

You can do a macro:

#define QEMU_SECURITY_WRAPPED(func) func

And then use it in the functions that wrap the function like:

int
qemuSecurityRestoreDiskLabel(virQEMUDriverPtr driver,
                             virDomainObjPtr vm,
                             virDomainDiskDefPtr disk)
{
    int ret = -1;

    if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
        virSecurityManagerTransactionStart(driver->securityManager) < 0)
        goto cleanup;

    if (QEMU_SECURITY_WRAPPED(virSecurityManagerRestoreDiskLabel)(driver->securityManager,
                                                                  vm->def,
                                                                  disk) < 0)
        goto cleanup;

    if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
        virSecurityManagerTransactionCommit(driver->securityManager,
                                            vm->pid) < 0)
        goto cleanup;

    ret = 0;
 cleanup:
    virSecurityManagerTransactionAbort(driver->securityManager);
    return ret;
}

But the conditions are to use a very distinctive name of the macro and
the macro actually not doing much so that the readability of the code is
preserved, while having an anchor point for automatically looking up the
function names that were wrapped.

Yet another option would be to do:

#define QEMU_SECURITY_WRAPPED

void QEMU_SECURITY_WRAPPED qemuSecurityRestoreAllLabel(virQEMUDriverPtr driver,
                                                       virDomainObjPtr vm,
                                                       bool migrated);

In that case you need some 'sed' magic to figure out the function name
though.

Peter
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