This was added to fix a regression with support for the default runc
shipped with CentOS 7.
The version of runc that is installed by default on CentOS 7 is
1.0.0-rc2 which uses OCI spec 1.0.0-rc2-dev.
This is a prerelease of the OCI spec, which defines the capabilities
section of a process configuration to be a flat list of capabilities
(e.g. SYS_ADMIN, SYS_PTRACE, SYS_RAWIO, etc.)
https://github.com/opencontainers/runtime-spec/blob/v1.0.0-rc2/config.md#process-configuration
By the time the official 1.0.0 version of the OCI spec came out, the
capabilities section of a process configuration was expanded to include
embedded fields for effective, bounding, inheritable, permitted and
ambient (each of which can contain a flat list of capabilities of the
form SYS_ADMIN, SYS_PTRACE, SYS_RAWIO, etc.)
https://github.com/opencontainers/runtime-spec/blob/v1.0.0/config.md#linux-process
Previously, we only inspected the capabilities section of a process
configuration assuming it was in the format of OCI spec 1.0.0.
This patch makes sure we can parse the capaibilites in either format.
Signed-off-by: Kevin Klues <kklues@nvidia.com>
