Re: [PATCH 1/1] landlock: Mention -1 return code on failure

[Petr Vorel <pvorel@suse.cz>]

> Hi Petr,

> On Fri, Jul 12, 2024 at 03:09:04PM GMT, Petr Vorel wrote:
> > Mention -1 return code on failure for landlock_add_rule(),
> > landlock_create_ruleset() and landlock_restrict_self().

> > Although it's a common rule to return -1 on error, it's better to be
> > explicit (as the other man pages are).

> > Fixes: a01d04a69 ("landlock_add_rule.2: Document new syscall")
> > Fixes: ca5163697 ("landlock_create_ruleset.2: Document new syscall")
> > Fixes: 3f7e4f808 ("landlock_restrict_self.2: Document new syscall")
> > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > ---
> > FYI we test return codes in LTP.

> > https://lore.kernel.org/ltp/20240711-landlock-v3-0-c7b0e9edf9b0@suse.com/
> > https://lore.kernel.org/ltp/20240711201306.98519-1-pvorel@suse.cz/

> > Kind regards,
> > Petr

> Thanks!  Please see a comment below.


> >  man/man2/landlock_add_rule.2       | 4 ++++
> >  man/man2/landlock_create_ruleset.2 | 4 ++++
> >  man/man2/landlock_restrict_self.2  | 4 ++++
> >  3 files changed, 12 insertions(+)

> > diff --git a/man/man2/landlock_add_rule.2 b/man/man2/landlock_add_rule.2
> > index 4b95afb07..6fdc2f896 100644
> > --- a/man/man2/landlock_add_rule.2
> > +++ b/man/man2/landlock_add_rule.2
> > @@ -79,6 +79,10 @@ must be 0.
> >  On success,
> >  .BR landlock_add_rule ()
> >  returns 0.
> > +On error,
> > +\-1 is returned and
> > +.I errno
> > +is set to indicate the cause of the error.
> >  .SH ERRORS
> >  .BR landlock_add_rule ()
> >  can fail for the following reasons:
> > diff --git a/man/man2/landlock_create_ruleset.2 b/man/man2/landlock_create_ruleset.2
> > index e62a3f9b9..4f638e85c 100644
> > --- a/man/man2/landlock_create_ruleset.2
> > +++ b/man/man2/landlock_create_ruleset.2
> > @@ -86,6 +86,10 @@ returns a new Landlock ruleset file descriptor,
> >  or a Landlock ABI version,
> >  according to
> >  .IR flags .
> > +On error,
> > +\-1 is returned and
> > +.I errno
> > +is set to indicate the cause of the error.

> I think the common wording is s/the cause of //

> Michael unified these a few years ago.

Yes, you're right, it's mentioned in Changes.old.
But I copied that from man/man2/mount_setattr.2 and it's on several places:

$ git grep "the cause of the error" man/ | wc -l
12

I'll send v2 later today or on Monday.

Kind regards,
Petr

> Cheers,
> Alex

> >  .SH ERRORS
> >  .BR landlock_create_ruleset ()
> >  can fail for the following reasons:
> > diff --git a/man/man2/landlock_restrict_self.2 b/man/man2/landlock_restrict_self.2
> > index 43f15c932..88850ddfb 100644
> > --- a/man/man2/landlock_restrict_self.2
> > +++ b/man/man2/landlock_restrict_self.2
> > @@ -72,6 +72,10 @@ must be 0.
> >  On success,
> >  .BR landlock_restrict_self ()
> >  returns 0.
> > +On error,
> > +\-1 is returned and
> > +.I errno
> > +is set to indicate the cause of the error.
> >  .SH ERRORS
> >  .BR landlock_restrict_self ()
> >  can fail for the following reasons:
> > -- 
> > 2.45.2