Re: [PATCH v2] proc(5): clarify the root symlink and mount namespaces

["Michael Kerrisk (man-pages)" <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 10/07/2016 09:21 PM, Mike Frysinger wrote:
> On 07 Oct 2016 14:33, Michael Kerrisk (man-pages) wrote:
>> On 10/06/2016 07:23 PM, Mike Frysinger wrote:
>>> If the target process is in a different mount namespace, the root symlink
>>> actually shows that view of the filesystem.  As an example:
>>>  /* Terminal 1 */
>>>  $ unshare -Urnm
>>>  # mount -t tmpfs tmpfs /etc
>>>  # mount --bind /bin /dev
>>>  # echo $$
>>>  17168
>>>
>>>  /* Terminal 2 */
>>>  # ls /etc                          # Normal view of /etc files.
>>>  # ls /proc/17168/root/etc          # Empty view of the tmpfs.
>>>  # ls /dev                          # Normal view of /dev files.
>>>  # ls /proc/17168/root/dev          # Contents of /bin files.
>>
>> Thanks for the patch! And thanks for the commit message, which is I think
>> actually useful text for the man page itself, so I added it (in somewhat
>> modified form) to the page itself.
> 
> looks like some formatting is off ?

Thanks, Mike. Patch applied.

Cheers,

Michael

> --- a/man5/proc.5
> +++ b/man5/proc.5
> @@ -1525,7 +1525,7 @@ and in that shell we create some new mount points:
>  $ \fBPS1='sh1# ' unshare \-Urnm\fP
>  sh1# \fBmount \-t tmpfs tmpfs /etc\fP  # Mount empty tmpfs at /etc
>  sh1# \fBmount \-\-bind /usr /dev\fP     # Mount /usr at /dev
> -sh1# \fBecho $$
> +sh1# \fBecho $$\fP
>  27123
>  .in
>  .fi
> @@ -1533,10 +1533,10 @@ sh1# \fBecho $$
>  In a second terminal window, in the initial mount namespace,
>  we look at the contents of the corresponding mounts in
>  the initial and new namespaces:
> -    
> +
>  .nf
>  .in +4n
> -$ \fBPS1='sh2# ' sudo sh
> +$ \fBPS1='sh2# ' sudo sh\fP
>  sh2# \fBls /etc | wc \-l\fP                  # In initial NS
>  309
>  sh2# \fBls /proc/27123/root/etc | wc \-l\fP  # /etc in other NS
> 


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