Re: [PATCH v2 bpf-next 0/7] libbpf: add tracing attach APIs

Stanislav Fomichev
2019-06-21T21:21:13Z

On 06/20, Andrii Nakryiko wrote:
> This patchset adds the following APIs to allow attaching BPF programs to
> tracing entities:
> - bpf_program__attach_perf_event for attaching to any opened perf event FD,
> allowing users full control;
> - bpf_program__attach_kprobe for attaching to kernel probes (both entry and
> return probes);
> - bpf_program__attach_uprobe for attaching to user probes (both entry/return);
> - bpf_program__attach_tracepoint for attaching to kernel tracepoints;
> - bpf_program__attach_raw_tracepoint for attaching to raw kernel tracepoint
> (wrapper around bpf_raw_tracepoint_open);
>
> This set of APIs makes libbpf more useful for tracing applications.
>
> Pre-patch #1 makes internal libbpf_strerror_r helper function work w/ negative
> error codes, lifting the burder off callers to keep track of error sign.
> Patch #2 adds attach_perf_event, which is the base for all other APIs.
> Patch #3 adds kprobe/uprobe APIs.
> Patch #4 adds tracepoint/raw_tracepoint APIs.
> Patch #5 converts one existing test to use attach_perf_event.
> Patch #6 adds new kprobe/uprobe tests.
> Patch #7 converts all the selftests currently using tracepoint to new APIs.
>
> v1->v2:
> - preserve errno before close() call (Stanislav);
> - use libbpf_perf_event_disable_and_close in selftest (Stanislav);
> - remove unnecessary memset (Stanislav);
Reviewed-by: Stanislav Fomichev <sdf@google.com>

Thanks!

> Andrii Nakryiko (7):
> libbpf: make libbpf_strerror_r agnostic to sign of error
> libbpf: add ability to attach/detach BPF to perf event
> libbpf: add kprobe/uprobe attach API
> libbpf: add tracepoint/raw tracepoint attach API
> selftests/bpf: switch test to new attach_perf_event API
> selftests/bpf: add kprobe/uprobe selftests
> selftests/bpf: convert existing tracepoint tests to new APIs
>
> tools/lib/bpf/libbpf.c | 346 ++++++++++++++++++
> tools/lib/bpf/libbpf.h | 17 +
> tools/lib/bpf/libbpf.map | 6 +
> tools/lib/bpf/str_error.c | 2 +-
> .../selftests/bpf/prog_tests/attach_probe.c | 151 ++++++++
> .../bpf/prog_tests/stacktrace_build_id.c | 49 +--
> .../bpf/prog_tests/stacktrace_build_id_nmi.c | 24 +-
> .../selftests/bpf/prog_tests/stacktrace_map.c | 42 +--
> .../bpf/prog_tests/stacktrace_map_raw_tp.c | 14 +-
> .../bpf/prog_tests/task_fd_query_rawtp.c | 10 +-
> .../bpf/prog_tests/task_fd_query_tp.c | 51 +--
> .../bpf/prog_tests/tp_attach_query.c | 56 +--
> .../selftests/bpf/progs/test_attach_probe.c | 55 +++
> 13 files changed, 651 insertions(+), 172 deletions(-)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/attach_probe.c
> create mode 100644 tools/testing/selftests/bpf/progs/test_attach_probe.c
>
> --
> 2.17.1
>