Re: [PATCH] uuidgen: print warning if uuidd isn't running

[Ludwig Nussel <ludwig.nussel@suse.de>]

Karel Zak wrote:
> On Tue, Jun 14, 2011 at 01:45:34PM +0200, Karel Zak wrote:
> > On Wed, Jun 08, 2011 at 03:35:01PM +0200, Ludwig Nussel wrote:
> > > ---
> > >  misc-utils/uuidgen.c |    4 +++-
> > >  1 files changed, 3 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/misc-utils/uuidgen.c b/misc-utils/uuidgen.c
> > > index 3cf6ec9..47f8e8f 100644
> > > --- a/misc-utils/uuidgen.c
> > > +++ b/misc-utils/uuidgen.c
> > > @@ -59,7 +59,9 @@ main (int argc, char *argv[])
> > >  
> > >  	switch (do_type) {
> > >  	case DO_TYPE_TIME:
> > > -		uuid_generate_time(uu);
> > > +		if (uuid_generate_time_safe(uu)) {
> > > +			fprintf(stderr, _("Warning: uuidd not running or not operational. Time based uuid may not be unique.\n"));
> > 
> > IMHO this is overkill -- the uuidd is used very rarely (usually on
> > large systems with SAP) and it's disabled by default in many
> > distributions, but the uuidgen(1) util is available everywhere and
> > used probably often used by admins/scripts.

That's the problem exactly. uuidgen seems to work for them at first
until lots of uuids within a short time are required. It's a mean
trap.

> > It would be better to add some WARNING section to the uuidgen(1) man
> > page to inform users about the disadvantage.

Well, who reads docu if uuidgen -t appears to work?

>  ... we can also add a new option (e.g. --safe) to use 
>  uuid_generate_time_safe().

... or make -t fail if it's not safe and add a --unsafe option. That
would be the fail-safe approach :-)

cu
Ludwig

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