[sosreport] add --sysroot option

Add a --sysroot=SYSROOT option to specify that the root file system to
be inspected is mounted at SYSROOT.

This allows basic support for container environments where sos is
running in a container and inspecting the containing host and its
environment ('superspection').

For this to work currently the following conditions must be met:

- sos is sufficiently privileged to read and search relevant file
  system paths within SYSROOT

- sos must share the PID and network namespace of the target host

- binaries called by sos must be present and executable in the
  SYSROOT inherited by sos. If PATH includes paths inside SYSROOT
  appropriate values must be set for LD_LIBRARY_PATH to allow
  shared executables to be linked.

Signed-off-by: Bryn M. Reeves <bmr@redhat.com>

0 files changed, 0 insertions, 0 deletions