Re: [PATCH] maps.2: fd for a file mapping must be opened for reading

["Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>]

On 04/04/2014 10:24 AM, Andrey Vagin wrote:
> Here is no difference between MAP_SHARED and MAP_PRIVATE.

Thanks, Andrey. That man page text has been there for a very long time,
but but does not seem to correspond to the truth in any kernel version
going back even to Linux 1.0. Patch applied.

Cheers,

Michael


> do_mmap_pgoff()
> 	switch (flags & MAP_TYPE) {
> 	case MAP_SHARED:
> 	...
> 	/* fall through */
> 	case MAP_PRIVATE:
> 		if (!(file->f_mode & FMODE_READ))
> 			return -EACCES;
> 
> Signed-off-by: Andrey Vagin <avagin@openvz.org>
> ---
>  man2/mmap.2 | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/man2/mmap.2 b/man2/mmap.2
> index c0fd321..b469f84 100644
> --- a/man2/mmap.2
> +++ b/man2/mmap.2
> @@ -393,9 +393,7 @@ is set (probably to
>  .TP
>  .B EACCES
>  A file descriptor refers to a non-regular file.
> -Or
> -.B MAP_PRIVATE
> -was requested, but
> +Or a file mapping was requested, but
>  .I fd
>  is not open for reading.
>  Or
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/