* Add map-in-map support
Replace UM ebpf_map_update/delete_element with libbpf-compliant
bpf_map_update/delete_elem
This adds the basic functionality needed for #375
Not in this PR, but in a subsequent PR:
* ensure that all inner maps match the one specified by inner_map_idx,
much like prog_types have to match in a prog_array.
* ensure that putting a prog_array in an array of maps adheres to the
prog_array contract that any associated progs have to match the
type of the calling program.
* read a map id not fd when UM reads the value (will be done together
with issue #396 since also affects prog_arrays)
Signed-off-by: Dave Thaler <dthaler@microsoft.com>
* add UNLINK operation
* Some fixes:
1. Added attach_lock to synchronize multiple detach calls on same link object.
2. ebpf_extension_unload() should be called from ebpf_link_detach_program()
3. Changed return type of ebpf_program_get_properties to void.
* Update libs/execution_context/ebpf_program.c
Co-authored-by: Dave Thaler <dthaler@microsoft.com>