Revert "Revert "Add docker exec run a command in privileged mode""

This reverts commit 40b71adee390e9c06471b89ed845132b4ec80177.

Original commit (for which this is effectively a rebased version) is
72a500e9e5929b038816d8bd18d462a19e571c99 and was provided by Lei Jitang
<leijitang@huawei.com>.

Signed-off-by: Tim Dettrick <t.dettrick@uq.edu.au>

contrib/completion/bash/docker

@@ -675,7 +675,7 @@ _docker_exec() {
 
 	case "$cur" in
 		-*)
-			COMPREPLY=( $( compgen -W "--detach -d --help --interactive -i -t --tty -u --user" -- "$cur" ) )
+			COMPREPLY=( $( compgen -W "--detach -d --help --interactive -i --privileged -t --tty -u --user" -- "$cur" ) )
 			;;
 		*)
 			__docker_containers_running

docs/reference/commandline/exec.md

@@ -17,6 +17,7 @@ weight=1
 
       -d, --detach=false         Detached mode: run command in the background
       -i, --interactive=false    Keep STDIN open even if not attached
+      --privileged=false         Give extended privileges to the command
       -t, --tty=false            Allocate a pseudo-TTY
       -u, --user=                Username or UID (format: <name|uid>[:<group|gid>])
 

man/docker-exec.1.md

@@ -9,6 +9,7 @@ docker-exec - Run a command in a running container
 [**-d**|**--detach**[=*false*]]
 [**--help**]
 [**-i**|**--interactive**[=*false*]]
+[**--privileged**[=*false*]]
 [**-t**|**--tty**[=*false*]]
 [**-u**|**--user**[=*USER*]]
 CONTAINER COMMAND [ARG...]
@@ -33,6 +34,13 @@ container is unpaused, and then run
 **-i**, **--interactive**=*true*|*false*
    Keep STDIN open even if not attached. The default is *false*.
 
+**--privileged**=*true*|*false*
+   Give extended privileges to the process to run in a running container. The default is *false*.
+
+   By default, the process run by docker exec in a running container
+have the same capabilities of the container. By setting --privileged will give
+all the capabilities to the process.
+
 **-t**, **--tty**=*true*|*false*
    Allocate a pseudo-TTY. The default is *false*.