ioctl() on a file, directory, pipe or character device threw "request
0x20006601 ... is not implemented" for FIOCLEX, and the same for
FIONCLEX, although the close-on-exec flag they change is already kept
for these descriptors and reported by fcntl(F_GETFD).
FreeBSD 11.4 handles both requests in kern_ioctl() for every descriptor,
before the request reaches the file's own ioctl, by changing the flag
F_GETFD reads. sys/kern/sys_generic.c, kern_ioctl():
case FIONCLEX:
fdp->fd_ofiles[fd].fde_flags &= ~UF_EXCLOSE;
goto out;
case FIOCLEX:
fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE;
goto out;
sys/kern/kern_descrip.c, kern_fcntl():
case F_GETFD:
...
td->td_retval[0] =
(fde->fde_flags & UF_EXCLOSE) ? FD_CLOEXEC : 0;
Both requests now set or clear that flag and return 0. libuv before 1.44
sets close-on-exec this way on FreeBSD (uv__cloexec_ioctl).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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