Re: [PATCH for-5.1 2/2] tpm: Improve help on TPM types when none are available

[Stefan Berger]

On 7/23/20 8:49 AM, Philippe Mathieu-Daudé wrote:
> On 7/23/20 1:58 PM, Markus Armbruster wrote:
> > Help is a bit awkward when no TPM types are built into QEMU:
> >
> >      $ upstream-qemu -tpmdev nonexistent,id=tpm0
> >      upstream-qemu: -tpmdev nonexistent,id=tpm0: Parameter 'type' expects a TPM 
> > backend type
> >      Supported TPM types (choose only one):
> >
> > Improve to
> >
> >      upstream-qemu: -tpmdev nonexistent,id=tpm0: Parameter 'type' expects a TPM 
> > backend type
> >      No TPM backend types are available
> >
> > Signed-off-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>


Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>


> > ---
> >   tpm.c | 13 +++++++++----
> >   1 file changed, 9 insertions(+), 4 deletions(-)
> >
> > diff --git a/tpm.c b/tpm.c
> > index f6045bb6da..cab206355a 100644
> > --- a/tpm.c
> > +++ b/tpm.c
> > @@ -47,18 +47,23 @@ tpm_be_find_by_type(enum TpmType type)
> >    */
> >   static void tpm_display_backend_drivers(void)
> >   {
> > +    bool got_one = false;
> >       int i;
> >   
> > -    fprintf(stderr, "Supported TPM types (choose only one):\n");
> > -
> >       for (i = 0; i < TPM_TYPE__MAX; i++) {
> >           const TPMBackendClass *bc = tpm_be_find_by_type(i);
> >           if (!bc) {
> >               continue;
> >           }
> > -        fprintf(stderr, "%12s   %s\n", TpmType_str(i), bc->desc);
> > +        if (!got_one) {
> > +            error_printf("Supported TPM types (choose only one):\n");
> > +            got_one = true;
> > +        }
> > +        error_printf("%12s   %s\n", TpmType_str(i), bc->desc);
> > +    }
> > +    if (!got_one) {
> > +        error_printf("No TPM backend types are available\n");
> >       }
> > -    fprintf(stderr, "\n");
> >   }
> >   
> >   /*