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

Andrii Nakryiko
2019-06-21T04:56:03Z

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);

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

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2.17.1