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

On 07 Oct 2016 14:33, Michael Kerrisk (man-pages) wrote:

On 10/06/2016 07:23 PM, Mike Frysinger wrote:

quoted

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 ?
-mike

--- 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