def _change_privilege(user, group=user)
uid, gid = Process.euid, Process.egid
begin
target_uid = Etc.getpwnam(user).uid
rescue ArgumentError => e
Chef::Application.fatal!("Failed to get UID for user #{user}, does it exist? #{e.message}")
return false
end
begin
target_gid = Etc.getgrnam(group).gid
rescue ArgumentError => e
Chef::Application.fatal!("Failed to get GID for group #{group}, does it exist? #{e.message}")
return false
end
if (uid != target_uid) or (gid != target_gid)
Process.initgroups(user, target_gid)
Process::GID.change_privilege(target_gid)
Process::UID.change_privilege(target_uid)
end
true
rescue Errno::EPERM => e
Chef::Application.fatal!("Permission denied when trying to change #{uid}:#{gid} to #{target_uid}:#{target_gid}. #{e.message}")
end