Re: git: ba0d9b43e940 - main - kern_descrip.c: provide helpers to translate between fd flags namespace

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 <kib@FreeBSD.org>
> AuthorDate: 2025-07-08 16:30:29 +0000
> Commit:     Konstantin Belousov <kib@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


-- 
John Baldwin