Date: Fri, 11 Jul 2025 22:00:18 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: ba0d9b43e940 - main - kern_descrip.c: provide helpers to translate between fd flags namespace Message-ID: <aHFfQnpM3LkxByRm@kib.kiev.ua> In-Reply-To: <c9bde9bb-c914-4401-aff6-cc830944b0d6@FreeBSD.org> References: <202507082149.568LnGOU086303@gitrepo.freebsd.org> <c9bde9bb-c914-4401-aff6-cc830944b0d6@FreeBSD.org>
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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 <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 > 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 <kib@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));
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