On Fri, Jul 11, 2025 at 11:46:33AM -0400, John Baldwin wrote:
> On 7/8/25 17:49, Konstantin Belousov wrote:
> > The branch main has been updated by kib:
> >
> > URL:
> > https://cgit.FreeBSD.org/src/commit/?id=ba0d9b43e940077f4025e7e4e85d16c8d525db79
> >
> > commit ba0d9b43e940077f4025e7e4e85d16c8d525db79
> > Author: Konstantin Belousov <k...@freebsd.org>
> > AuthorDate: 2025-07-08 16:30:29 +0000
> > Commit: Konstantin Belousov <k...@freebsd.org>
> > CommitDate: 2025-07-08 21:48:59 +0000
> >
> > kern_descrip.c: provide helpers to translate between fd flags namespace
> > Reviewed by: markj
> > Sponsored by: The FreeBSD Foundation
> > Differential revision: https://reviews.freebsd.org/D51206
> > ---
> > sys/kern/kern_descrip.c | 110
> > +++++++++++++++++++++++++++++++++++++++---------
> > 1 file changed, 90 insertions(+), 20 deletions(-)
> >
> > diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
> > index 406236fc2723..2e1da2fdee29 100644
> > --- a/sys/kern/kern_descrip.c
> > +++ b/sys/kern/kern_descrip.c
> > @@ -480,6 +480,90 @@ kern_fcntl_freebsd(struct thread *td, int fd, int cmd,
> > intptr_t arg)
> > return (error);
> > }
> > +struct flags_trans_elem {
> > + u_int f;
> > + u_int t;
> > +};
> > +
> > +static u_int
> > +flags_trans(const struct flags_trans_elem *ftes, int nitems, u_int
> > from_flags)
> > +{
> > + u_int res;
> > + int i;
> > +
> > + res = 0;
> > + for (i = 0; i < nitems; i++) {
> > + if ((from_flags & ftes[i].f) != 0)
> > + res |= ftes[i].t;
> > + }
> > + return (res);
> > +}
> > +
> > +static uint8_t
> > +fd_to_fde_flags(int fd_flags)
> > +{
> > + static const struct flags_trans_elem fd_to_fde_flags_s[] = {
> > + { .f = FD_CLOEXEC, .t = UF_EXCLOSE },
> > + { .f = FD_CLOFORK, .t = UF_FOCLOSE },
> > + { .f = FD_RESOLVE_BENEATH, .t = UF_RESOLVE_BENEATH },
> > + };
> > +
> > + return (flags_trans(fd_to_fde_flags_s, nitems(fd_to_fde_flags_s),
> > + fd_flags));
> > +}
> > +
> > +static int
> > +fde_to_fd_flags(uint8_t fde_flags)
> > +{
> > + static const struct flags_trans_elem fde_to_fd_flags_s[] = {
> > + { .f = UF_EXCLOSE, .t = FD_CLOEXEC },
> > + { .f = UF_FOCLOSE, .t = FD_CLOFORK },
> > + { .f = UF_RESOLVE_BENEATH, .t = FD_RESOLVE_BENEATH },
> > + };
> > +
> > + return (flags_trans(fde_to_fd_flags_s, nitems(fde_to_fd_flags_s),
> > + fde_flags));
> > +}
> > +
> > +static uint8_t
> > +fddup_to_fde_flags(int fddup_flags)
> > +{
> > + static const struct flags_trans_elem fddup_to_fde_flags_s[] = {
> > + { .f = FDDUP_FLAG_CLOEXEC, .t = UF_EXCLOSE },
> > + { .f = FDDUP_FLAG_CLOFORK, .t = UF_FOCLOSE },
> > + };
> > +
> > + return (flags_trans(fddup_to_fde_flags_s, nitems(fddup_to_fde_flags_s),
> > + fddup_flags));
> > +}
> > +
> > +static uint8_t
> > +close_range_to_fde_flags(int close_range_flags)
> > +{
> > + static const struct flags_trans_elem close_range_to_fde_flags_s[] = {
> > + { .f = CLOSE_RANGE_CLOEXEC, .t = UF_EXCLOSE },
> > + { .f = CLOSE_RANGE_CLOFORK, .t = UF_FOCLOSE },
> > + };
> > +
> > + return (flags_trans(close_range_to_fde_flags_s,
> > + nitems(close_range_to_fde_flags_s), close_range_flags));
> > +}
> > +
> > +static uint8_t
> > +open_to_fde_flags(int open_flags, bool sticky_orb)
> > +{
> > + static const struct flags_trans_elem open_to_fde_flags_s[] = {
> > + { .f = O_CLOEXEC, .t = UF_EXCLOSE },
> > + { .f = O_CLOFORK, .t = UF_FOCLOSE },
> > + { .f = O_RESOLVE_BENEATH, .t = UF_RESOLVE_BENEATH },
> > + };
> > + _Static_assert(open_to_fde_flags_s[nitems(open_to_fde_flags_s) - 1].f ==
> > + O_RESOLVE_BENEATH, "O_RESOLVE_BENEATH must be last, for
> > sticky_orb");
>
> This broke the GCC builds it seems. GCC doesn't think that it can compute
> this
> expression at compile time.
>
> From https://ci.freebsd.org/job/FreeBSD-main-amd64-gcc14_build/1022/console:
>
> 10:32:02 /workspace/src/sys/kern/kern_descrip.c: In function
> 'open_to_fde_flags':
> 10:32:02 /workspace/src/sys/kern/kern_descrip.c:560:79: error: expression in
> static =
> 10:32:02 assertion is not constant
> 10:32:02 560 |
> _Static_assert(open_to_fde_flags_s[nitems(open_to_fde_flags=
> 10:32:02 _s) - 1].f =3D=3D
>
I am unable to propose anything better than the patch below. We have enough
#ifdef __clang__ in non-contrib sources already, so this should be not a
huge crime?
% rg -g '!contrib/*' __clang__ | wc -l
171
commit 96e6b15b0a1407af45ebe1ad38ee53627d09d16b
Author: Konstantin Belousov <k...@freebsd.org>
Date: Fri Jul 11 21:57:32 2025 +0300
kern_descrip.c: only allow complex expression in Static_assert() for clang
gcc cannot compute the assert expression.
Reported by: jhb
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index 93bdd41d1515..c4f5e586b0ed 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -557,8 +557,10 @@ open_to_fde_flags(int open_flags, bool sticky_orb)
{ .f = O_CLOFORK, .t = UF_FOCLOSE },
{ .f = O_RESOLVE_BENEATH, .t = UF_RESOLVE_BENEATH },
};
+#ifdef __clang__
_Static_assert(open_to_fde_flags_s[nitems(open_to_fde_flags_s) - 1].f ==
O_RESOLVE_BENEATH, "O_RESOLVE_BENEATH must be last, for
sticky_orb");
+#endif
return (flags_trans(open_to_fde_flags_s, nitems(open_to_fde_flags_s) -
(sticky_orb ? 0 : 1), open_flags));
