libbpf: Add ability to get/set per-program load flags

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@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211111051758.92283-2-andrii@kernel.org

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d869ebe..a823b5e 100644 (file)
--- 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 0390587..f69512a 100644 (file)
--- 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 b895861..256d5d4 100644 (file)
--- 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;