Jakub Kicinski a98bf57391 tools: bpftool: add support for reporting the effective cgroup progs
Takshak said in the original submission:

With different bpf attach_flags available to attach bpf programs specially
with BPF_F_ALLOW_OVERRIDE and BPF_F_ALLOW_MULTI, the list of effective
bpf-programs available to any sub-cgroups really needs to be available for
easy debugging.

Using BPF_F_QUERY_EFFECTIVE flag, one can get the list of not only attached
bpf-programs to a cgroup but also the inherited ones from parent cgroup.

So a new option is introduced to use BPF_F_QUERY_EFFECTIVE query flag here
to list all the effective bpf-programs available for execution at a specified
cgroup.

Reused modified test program test_cgroup_attach from tools/testing/selftests/bpf:
  # ./test_cgroup_attach

With old bpftool:

 # bpftool cgroup show /sys/fs/cgroup/cgroup-test-work-dir/cg1/
  ID       AttachType      AttachFlags     Name
  271      egress          multi           pkt_cntr_1
  272      egress          multi           pkt_cntr_2

Attached new program pkt_cntr_4 in cg2 gives following:

 # bpftool cgroup show /sys/fs/cgroup/cgroup-test-work-dir/cg1/cg2
  ID       AttachType      AttachFlags     Name
  273      egress          override        pkt_cntr_4

And with new "effective" option it shows all effective programs for cg2:

 # bpftool cgroup show /sys/fs/cgroup/cgroup-test-work-dir/cg1/cg2 effective
  ID       AttachType      AttachFlags     Name
  273      egress          override        pkt_cntr_4
  271      egress          override        pkt_cntr_1
  272      egress          override        pkt_cntr_2

Compared to original submission use a local flag instead of global
option.

We need to clear query_flags on every command, in case batch mode
wants to use varying settings.

v2: (Takshak)
 - forbid duplicated flags;
 - fix cgroup path freeing.

Signed-off-by: Takshak Chahande <ctakshak@fb.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Takshak Chahande <ctakshak@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-07-30 21:15:02 -07:00
2019-07-30 21:03:05 -07:00
2019-06-18 14:37:27 +01:00
2019-07-19 12:22:04 -07:00
2019-07-21 14:05:38 -07:00

Linux kernel
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