This patch series adds various observability APIs to bpf_link:
- each bpf_link now gets ID, similar to bpf_map and bpf_prog, by which
user-space can iterate over all existing bpf_links and create limited FD
from ID;
- allows to get extra object information with bpf_link general and
type-specific information;
- makes LINK_UPDATE operation allowed only for writable bpf_links and allows
to pin bpf_link as read-only file;
- implements `bpf link show` command which lists all active bpf_links in the
system;
- implements `bpf link pin` allowing to pin bpf_link by ID or from other
pinned path.
This RFC series is missing selftests and only limited amount of manual testing
was performed. But kernel implementation is hopefully in a good shape and
won't change much (unless some big issues are identified with the current
approach). It would be great to get feedback on approach and implementation,
before I invest more time in writing tests.
Andrii Nakryiko (8):
bpf: refactor bpf_link update handling
bpf: allow bpf_link pinning as read-only and enforce LINK_UPDATE
bpf: allocate ID for bpf_link
bpf: support GET_FD_BY_ID and GET_NEXT_ID for bpf_link
bpf: add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link
libbpf: add low-level APIs for new bpf_link commands
bpftool: expose attach_type-to-string array to non-cgroup code
bpftool: add bpf_link show and pin support
include/linux/bpf-cgroup.h | 14 --
include/linux/bpf.h | 34 ++-
include/linux/bpf_types.h | 6 +
include/uapi/linux/bpf.h | 31 +++
kernel/bpf/btf.c | 2 +
kernel/bpf/cgroup.c | 89 +++++++-
kernel/bpf/inode.c | 30 ++-
kernel/bpf/syscall.c | 387 +++++++++++++++++++++++++------
kernel/bpf/verifier.c | 2 +
kernel/cgroup/cgroup.c | 27 ---
tools/bpf/bpftool/cgroup.c | 28 +--
tools/bpf/bpftool/link.c | 403 +++++++++++++++++++++++++++++++++
tools/bpf/bpftool/main.c | 2 +
tools/bpf/bpftool/main.h | 37 +++
tools/include/uapi/linux/bpf.h | 31 +++
tools/lib/bpf/bpf.c | 19 +-
tools/lib/bpf/bpf.h | 4 +-
tools/lib/bpf/libbpf.map | 6 +
18 files changed, 983 insertions(+), 169 deletions(-)
create mode 100644 tools/bpf/bpftool/link.c
--
2.24.1
