[PATCH bpf-next 1/2] libbpf: add ability to get/set per-program load flags

[Andrii Nakryiko <andrii@xxxxxxxxxx>]

Add bpf_program__flags() API to retrieve prog_flags that will be (or
were) supplied to BPF_PROG_LOAD command.

Also add bpf_program__set_extra_flags() API to allow to set *extra*
flags, in addition to those determined by program's SEC() definition.
Such flags are logically OR'ed with libbpf-derived flags.

Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
 tools/lib/bpf/libbpf.c   | 14 ++++++++++++++
 tools/lib/bpf/libbpf.h   |  3 +++
 tools/lib/bpf/libbpf.map |  2 ++
 3 files changed, 19 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d869ebee1e27..a823b5ed705b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -8262,6 +8262,20 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
 	prog->expected_attach_type = type;
 }
 
+__u32 bpf_program__flags(const struct bpf_program *prog)
+{
+	return prog->prog_flags;
+}
+
+int bpf_program__set_extra_flags(struct bpf_program *prog, __u32 extra_flags)
+{
+	if (prog->obj->loaded)
+		return libbpf_err(-EBUSY);
+
+	prog->prog_flags |= extra_flags;
+	return 0;
+}
+
 #define SEC_DEF(sec_pfx, ptype, atype, flags, ...) {			    \
 	.sec = sec_pfx,							    \
 	.prog_type = BPF_PROG_TYPE_##ptype,				    \
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 039058763173..f69512ae8505 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -493,6 +493,9 @@ LIBBPF_API void
 bpf_program__set_expected_attach_type(struct bpf_program *prog,
 				      enum bpf_attach_type type);
 
+LIBBPF_API __u32 bpf_program__flags(const struct bpf_program *prog);
+LIBBPF_API int bpf_program__set_extra_flags(struct bpf_program *prog, __u32 extra_flags);
+
 LIBBPF_API int
 bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog_fd,
 			       const char *attach_func_name);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index b895861a13c0..256d5d4be951 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -397,8 +397,10 @@ LIBBPF_0.6.0 {
 		bpf_object__prev_program;
 		bpf_prog_load_deprecated;
 		bpf_prog_load;
+		bpf_program__flags;
 		bpf_program__insn_cnt;
 		bpf_program__insns;
+		bpf_program__set_extra_flags;
 		btf__add_btf;
 		btf__add_decl_tag;
 		btf__raw_data;
-- 
2.30.2