Re: [PATCH] Add copy_file_range system call

[Rich Felker <dalias@libc.org>]

On Mon, Aug 19, 2019 at 11:41:14PM +0000, Árni Dagur wrote:
> This patch was based on commit 53147f9, which added splice and vmsplice.
> ---
>  The function signature in the glibc manpage specifies `loff_t` instead
>  of `off_t`, for both `copy_file_range` and `splice`. In musl, however, 
>  the function signature for `splice` specifies `off_t`, so I did the
>  same here. I'm not an experienced C programmer, so that may have been
>  wrong.
> 
>  include/unistd.h            | 1 +
>  src/linux/copy_file_range.c | 8 ++++++++
>  2 files changed, 9 insertions(+)
>  create mode 100644 src/linux/copy_file_range.c
> 
> diff --git a/include/unistd.h b/include/unistd.h
> index 9485da7a..00cc7042 100644
> --- a/include/unistd.h
> +++ b/include/unistd.h
> @@ -188,6 +188,7 @@ char *get_current_dir_name(void);
>  int syncfs(int);
>  int euidaccess(const char *, int);
>  int eaccess(const char *, int);
> +ssize_t copy_file_range(int fd_in, off_t *off_in, int fd_out, off_t *off_out, size_t len, unsigned flags);
>  #endif

Oh, one other detail I missed: the argument names here are not valid.
To be valid they'd need to be in the reserved namespace, but musl
policy is not to use them at all in prototypes. I can fix this when
applying, so no problem.

Rich