[CRIU] [PATCH 05/14] userns: define protobuf messages for uid and gid maps

[Pavel Emelyanov]

On 10/14/2014 03:38 PM, Andrey Vagin wrote:
> Normally, one of the first steps after creating a new user namespace is
> to define the mappings used for the user and group IDs of the processes
> that will be created in that namespace. This is done by writing mapping
> information to the /proc/PID/uid_map and /proc/PID/gid_map files
> corresponding to one of the processes in the user namespace.
> 
> Signed-off-by: Andrey Vagin <avagin at openvz.org>
> ---
>  protobuf/Makefile     |  1 +
>  protobuf/userns.proto | 10 ++++++++++
>  2 files changed, 11 insertions(+)
>  create mode 100644 protobuf/userns.proto
> 
> diff --git a/protobuf/Makefile b/protobuf/Makefile
> index 509f3c3..983629e 100644
> --- a/protobuf/Makefile
> +++ b/protobuf/Makefile
> @@ -62,6 +62,7 @@ proto-obj-y	+= siginfo.o
>  proto-obj-y	+= rpc.o
>  proto-obj-y	+= ext-file.o
>  proto-obj-y	+= cgroup.o
> +proto-obj-y	+= userns.o
>  
>  proto		:= $(proto-obj-y:.o=)
>  proto-c		:= $(proto-obj-y:.o=.pb-c.c)
> diff --git a/protobuf/userns.proto b/protobuf/userns.proto
> new file mode 100644
> index 0000000..9428549
> --- /dev/null
> +++ b/protobuf/userns.proto
> @@ -0,0 +1,10 @@
> +message uid_gid_extent {
> +	required uint32 first		= 1;
> +	required uint32 lower_first	= 2;
> +	required uint32 count		= 3;
> +}
> +
> +message userns_entry {
> +	repeated uid_gid_extent uid_map	= 1;

Why repeated? Can one userns have more than one mapping?

> +	repeated uid_gid_extent gid_map = 2;
> +}
>