[PATCH v4 3/5] Linux: Add close_range

[Alyssa Ross]

Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org> writes:

> diff --git a/manual/llio.texi b/manual/llio.texi
> index c0a53e1a6e..c1f54f4a8a 100644
> --- a/manual/llio.texi
> +++ b/manual/llio.texi
> @@ -284,6 +284,48 @@ of trying to close its underlying file descriptor with @code{close}.
>  This flushes any buffered output and updates the stream object to
>  indicate that it is closed.
>  
> +@deftypefun int close_range (unsigned int @var{lowfd}, unsigned int @var{maxfd}, int @var{flags})
> +@standards{Linux, unistd.h}
> +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}}
> +@c This is a syscall for Linux v5.9.  There is no fallback emulation for
> +@c older kernels.
> +
> +The function @code{close_range} closes the file descriptor from @var{lowfd}
> +to @var{maxfd} (inclusive).  This function is similar to call @code{close} in
> +specified file descriptor range depending on the @var{flags}.
> +
> +This is function is only supportted on recent Linux versions and @theglibc{}

Typo here: "supportted"

> +does not provide any fallback (the application will need to handle possible
> +@code{ENOSYS}).
> +
> +The @var{flags} add options on how the files are closes.  Linux currently
> +supports:
> +
> +@vtable @code
> +@item CLOSE_RANGE_UNSHARE
> +Unshare the file descriptor table before closing file descriptors.
> +@end vtable
> +
> +The normal return value from @code{close_range} is @math{0}; a value
> +of @math{-1} is returned in case of failure.  The following @code{errno} error
> +conditions are defined for this function:
> +
> +@table @code
> +@item EINVAL
> +The @var{lowfd} value is larger than @var{maxfd} or an unsupported @var{flags}
> +is used.
> +
> +@item ENOMEM
> +Either there is not enough memory for the operation, or the process is
> +out of address space.
> +
> +@item EMFILE
> +The process has too many files open.
> +The maximum number of file descriptors is controlled by the
> +@end table
> +@end deftypefun
> +
> +
>  @node I/O Primitives
>  @section Input and Output Primitives
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