On Thu, Mar 07, 2019 at 10:26:22AM +0100, Daniel Borkmann wrote: > On 03/05/2019 11:47 PM, Javier Honduvilla Coto wrote: > > Hi all, > > > > This patch add the bpf_progenyof helper which receives a PID and returns > > 1 if the process currently being executed is in the process hierarchy, > > including itself or 0 if not. > > > > This is very useful in tracing programs when we want to filter by a > > given PID and all the children it might have. The current workarounds > > most people implement for this purpose have issues: > > > > - Attaching to process spawning syscalls and dynamically add those PIDs > > to some bpf map that would be used to filter is cumbersome and > > potentially racy. > > - Unrolling some loop to perform what this helper is doing consumes lots > > of instructions. That and the impossibility to jump backwards makes it > > really hard to be correct in really large process chains. > > > > Let me know what do you think! > > > > Thanks, > > > > --- > > Changed in V3: > > - Removed RCU read (un)locking as BPF programs alredy run in RCU > > locked > > context > > - progenyof(0) now returns 1, which, semantically makes more sense > > - Added new test case for PID 0 and changed sentinel value for > > errors > > - Rebase on latest bpf-next/master > > - Used my work email as somehow I accidentally used my personal one > > in v2 > > > > Changed in V2: > > - Adding missing docs in include/uapi/linux/bpf.h > > > > Javier Honduvilla Coto (3): > > bpf: add bpf_progenyof helper > > bpf: sync kernel uapi headers > > bpf: add tests for bpf_progenyof > > > > include/linux/bpf.h | 1 + > > include/uapi/linux/bpf.h | 10 +- > > kernel/bpf/core.c | 1 + > > kernel/bpf/helpers.c | 32 +++ > > kernel/trace/bpf_trace.c | 2 + > > tools/include/uapi/linux/bpf.h | 9 +- > > tools/testing/selftests/bpf/.gitignore | 1 + > > tools/testing/selftests/bpf/Makefile | 2 +- > > tools/testing/selftests/bpf/bpf_helpers.h | 1 + > > .../selftests/bpf/progs/test_progenyof_kern.c | 46 +++ > > .../selftests/bpf/test_progenyof_user.c | 268 ++++++++++++++++++ > > 11 files changed, 370 insertions(+), 3 deletions(-) > > create mode 100644 tools/testing/selftests/bpf/progs/test_progenyof_kern.c > > create mode 100644 tools/testing/selftests/bpf/test_progenyof_user.c > > > > bpf-next is closed right now due to merge window, please resubmit once it > opens, thanks!
Just did! Thanks :)
