Date: Sun, 15 Nov 2020 13:36:01 -0600 From: "Brandon Bergren" <bdragon@FreeBSD.org> To: "Scott Long" <scottl@samsco.org> Cc: "Jessica Clarke" <jrtc27@freebsd.org>, "Scott Long" <scottl@FreeBSD.org>, src-committers <src-committers@freebsd.org>, svn-src-all <svn-src-all@freebsd.org>, svn-src-head <svn-src-head@freebsd.org> Subject: Re: svn commit: r367701 - head/lib/libutil Message-ID: <76667692-13ef-4522-ab23-240a1f6d57f3@www.fastmail.com> In-Reply-To: <A572CEDC-5869-4BAF-95D1-6B9AC50C0ED6@samsco.org> References: <202011150748.0AF7mqW3016900@repo.freebsd.org> <D5492BB4-A282-4E35-B02F-1216769FDA51@freebsd.org> <A39C12CC-D3D6-4166-9089-7466FA1C2B2D@samsco.org> <329C4753-BB97-4C67-8CDA-39EB67E16CE8@freebsd.org> <EBD050A5-70AE-43E8-A9E1-CCD3BCA11180@samsco.org> <f9904238-3923-40c1-b478-c5249821ed09@www.fastmail.com> <44B80F15-2BE7-4B7C-BC3D-B65511480E58@freebsd.org> <a54c3d86-8499-4c2b-a83f-9db79a12e3ec@www.fastmail.com> <A572CEDC-5869-4BAF-95D1-6B9AC50C0ED6@samsco.org>
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That would explain why I see what I see -- I did not install an updated =
libc yet.
On Sun, Nov 15, 2020, at 1:34 PM, Scott Long wrote:
> It is a magical namespace, in that it comes from libc, not from the=20=
> kernel. Please make sure that you=E2=80=99ve installed a more recent =
libc, I=20
> guess? I just did a full build and install, and I=E2=80=99m unable to=
=20
> replicate the problem. Maybe there=E2=80=99s a static-linked pkg runn=
ing=20
> around somewhere? I=E2=80=99m at a loss for better ideas.
>=20
> Scott
>=20
>=20
> > On Nov 15, 2020, at 12:30 PM, Brandon Bergren <bdragon@FreeBSD.org> =
wrote:
> >=20
> > I think the problem is that user.* is somehow magically namespaced, =
so doing a "dumb" sysctlbyname will get the wrong one.
> >=20
> > sysctl (the tool) does:
> > __sysctl("sysctl.name2oid user.localbase",2,0xfffffbfffde98,0xfffffb=
fffda98,0x810809000,14) =3D 0 (0x0)
> > __sysctl("sysctl.oidfmt user.localbase",4,0xfffffbfffdef8,0xfffffbff=
fd690,0x0,0) =3D 0 (0x0)
> > __sysctl("sysctl.name { 8.21 }",4,0xfffffbfffc8f8,0xfffffbfffc480,0x=
0,0) =3D 0 (0x0)
> > __sysctl("sysctl.oidfmt user.localbase",4,0xfffffbfffd0f8,0xfffffbff=
fc488,0x0,0) =3D 0 (0x0)
> > __sysctl("user.localbase",2,0x0,0xfffffbfffc480,0x0,0) =3D 0 (0x0)
> > __sysctl("user.localbase",2,0x81080a000,0xfffffbfffd0f8,0x0,0) =3D 0=
(0x0)
> >=20
> > and picks up /usr/local.
> >=20
> > whereas libutil is currently just doing
> > __sysctlbyname("user.localbase",14,0xfffffbfffd4f8,0xfffffbfffd440,0=
x0,0) =3D 0 (0x0)
> >=20
> > which is returning the builtin "" from the static kernel variable.
> >=20
> > On Sun, Nov 15, 2020, at 1:26 PM, Jessica Clarke wrote:
> >> On 15 Nov 2020, at 19:10, Brandon Bergren <bdragon@FreeBSD.org> wro=
te:
> >>>=20
> >>> On powerpc64 and powerpc64le, there is some really weird behavior =
happening around the sysctl itself:
> >>>=20
> >>> root@crow:~ # pkg
> >>> The package management tool is not yet installed on your system.
> >>> Do you want to fetch and install it now? [y/N]: N
> >>> root@crow:~ # sysctl user.localbase
> >>> user.localbase: /usr/local
> >>> root@crow:~ # pkg
> >>> The package management tool is not yet installed on your system.
> >>> Do you want to fetch and install it now? [y/N]: N
> >>> root@crow:~ # sysctl user.localbase=3D/usr/local
> >>> user.localbase: /usr/local -> /usr/local
> >>> root@crow:~ # pkg
> >>> pkg: not enough arguments
> >>> Usage: pkg [-v] [-d] [-l] [-N] [-j <jail name or id>|-c <chroot pa=
th>|-r <rootdir>] [-C <configuration file>] [-R <repo config dir>] [-o v=
ar=3Dvalue] [-4|-6] <command> [<args>]
> >>>=20
> >>> For more information on available commands and options see 'pkg he=
lp'.
> >>> root@crow:~ #=20
> >>>=20
> >>>=20
> >>> I would double check very closely that the sysctl is being called =
correctly, the sysctl tool manages to read it out, but libutil does not.=
> >>=20
> >> That's odd. What does truss say?
> >>=20
> >> Jess
> >>=20
> >>> On Sun, Nov 15, 2020, at 1:06 PM, Scott Long wrote:
> >>>>=20
> >>>>> On Nov 15, 2020, at 12:01 PM, Jessica Clarke <jrtc27@freebsd.org=
> wrote:
> >>>>>>=20
> >>>>>> I felt similar concerns, but my misunderstanding of strlcpy() d=
rove the
> >>>>>> result. Since the use case for getlocalbase() lends itself to =
also use
> >>>>>> strlcat()/strlcpy(), I was trying to replicate the API semantic=
s of those,
> >>>>>> at least to the limit of my understanding. Thanks for the feed=
back, I=E2=80=99ll
> >>>>>> look at it some more.
> >>>>>=20
> >>>>> Thanks. ENOMEM also feels inappropriate as no allocation is taki=
ng
> >>>>> place. Perhaps ENAMETOOLONG, which is used in similar cases for =
things
> >>>>> like gethostbyname? Though sysctlbyname uses ENOMEM instead... s=
igh.
> >>>>>=20
> >>>>=20
> >>>> Yep, I wasn=E2=80=99t happy with ENOMEM either but I couldn=E2=80=
=99t find anything better.
> >>>>=20
> >>>>> Also, if pathlen has already been checked against SSIZE_MAX (giv=
ing
> >>>>> EINVAL) and tmplen against pathlen there's no need to then check=
tmplen
> >>>>> against SSIZE_MAX.
> >>>>>=20
> >>>>=20
> >>>> Done.
> >>>>=20
> >>>>> I'd be happy to give a review on Phabricator if/when you have a =
new
> >>>>> patch.
> >>>>>=20
> >>>>=20
> >>>> https://reviews.freebsd.org/D27227
> >>>>=20
> >>>> Thanks,
> >>>> Scott
> >>>>=20
> >>>>=20
> >>>=20
> >>> --=20
> >>> Brandon Bergren
> >>> bdragon@FreeBSD.org
> >>=20
> >>=20
> >=20
> > --=20
> > Brandon Bergren
> > bdragon@FreeBSD.org
>=20
>
--=20
Brandon Bergren
bdragon@FreeBSD.org
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