bpftool: introduce cgroup tree command
This commit introduces a new bpftool command: cgroup tree.
The idea is to iterate over the whole cgroup tree and print
all attached programs.
I was debugging a bpf/systemd issue, and found, that there is
no simple way to listen all bpf programs attached to cgroups.
I did master something in bash, but after some time got tired of it,
and decided, that adding a dedicated bpftool command could be
a better idea.
So, here it is:
$ sudo ./bpftool cgroup tree
CgroupPath
ID AttachType AttachFlags Name
/sys/fs/cgroup/system.slice/systemd-machined.service
18 ingress
17 egress
/sys/fs/cgroup/system.slice/systemd-logind.service
20 ingress
19 egress
/sys/fs/cgroup/system.slice/systemd-udevd.service
16 ingress
15 egress
/sys/fs/cgroup/system.slice/systemd-journald.service
14 ingress
13 egress
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Quentin Monnet <quentin.monnet@netronome.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>