libbpf: Add per-program log buffer setter and getter

Allow to set user-provided log buffer on a per-program basis ([0]). This
gives great deal of flexibility in terms of which programs are loaded
with logging enabled and where corresponding logs go.

Log buffer set with bpf_program__set_log_buf() overrides kernel_log_buf
and kernel_log_size settings set at bpf_object open time through
bpf_object_open_opts, if any.

Adjust bpf_object_load_prog_instance() logic to not perform own log buf
allocation and load retry if custom log buffer is provided by the user.

  [0] Closes: https://github.com/libbpf/libbpf/issues/418

Signed-off-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

0 files changed, 0 insertions, 0 deletions