/usr/share/systemtap/tapset/offsetof.stpm is in systemtap-common 2.9-2ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 | @define offsetof(type, member) %(
( & @cast(0, @type) -> @member )
%)
@define module_offsetof(module, type, member) %(
( & @cast(0, @type, @module) -> @member )
%)
|