@@ -6862,6 +6862,8 @@ static int bpf_object_load_prog_instance(struct bpf_object *obj, struct bpf_prog
prog->name, err);
return err;
}
+ insns = prog->insns;
+ insns_cnt = prog->insns_cnt;
}
if (obj->gen_loader) {
@@ -8790,6 +8792,26 @@ size_t bpf_program__insn_cnt(const struct bpf_program *prog)
return prog->insns_cnt;
}
+int bpf_program__set_insns(struct bpf_program *prog,
+ struct bpf_insn *new_insns, size_t new_insn_cnt)
+{
+ struct bpf_insn *insns;
+
+ if (prog->obj->loaded)
+ return -EBUSY;
+
+ insns = libbpf_reallocarray(prog->insns, new_insn_cnt, sizeof(*insns));
+ if (!insns) {
+ pr_warn("prog '%s': failed to realloc prog code\n", prog->name);
+ return -ENOMEM;
+ }
+ memcpy(insns, new_insns, new_insn_cnt * sizeof(*insns));
+
+ prog->insns = insns;
+ prog->insns_cnt = new_insn_cnt;
+ return 0;
+}
+
int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
bpf_program_prep_t prep)
{
@@ -323,6 +323,24 @@ struct bpf_insn;
* different.
*/
LIBBPF_API const struct bpf_insn *bpf_program__insns(const struct bpf_program *prog);
+
+/**
+ * @brief **bpf_program__set_insns()** can set BPF program's underlying
+ * BPF instructions.
+ *
+ * WARNING: This is a very advanced libbpf API and users need to know
+ * what they are doing. This should be used from prog_prepare_load_fn
+ * callback only.
+ *
+ * @param prog BPF program for which to return instructions
+ * @param new_insns a pointer to an array of BPF instructions
+ * @param new_insn_cnt number of `struct bpf_insn`'s that form
+ * specified BPF program
+ * @return 0, on success; negative error code, otherwise
+ */
+LIBBPF_API int bpf_program__set_insns(struct bpf_program *prog,
+ struct bpf_insn *new_insns, size_t new_insn_cnt);
+
/**
* @brief **bpf_program__insn_cnt()** returns number of `struct bpf_insn`'s
* that form specified BPF program.
@@ -448,6 +448,7 @@ LIBBPF_0.8.0 {
bpf_object__open_subskeleton;
bpf_program__attach_kprobe_multi_opts;
bpf_program__attach_usdt;
+ bpf_program__set_insns;
libbpf_register_prog_handler;
libbpf_unregister_prog_handler;
} LIBBPF_0.7.0;
Adding bpf_program__set_insns that allows to set new instructions for program. This is a very advanced libbpf API and users need to know what they are doing. This should be used from prog_prepare_load_fn callback only. We can have changed instructions after calling prog_prepare_load_fn callback, reloading them. Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- tools/lib/bpf/libbpf.c | 22 ++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 18 ++++++++++++++++++ tools/lib/bpf/libbpf.map | 1 + 3 files changed, 41 insertions(+)