diff options
author | Jiri Olsa <jolsa@kernel.org> | 2022-05-10 09:46:57 +0200 |
---|---|---|
committer | Daniel Borkmann <daniel@iogearbox.net> | 2022-05-11 14:15:17 +0200 |
commit | b63b3c490eeeedd324e194929bd0aa8ba553f875 (patch) | |
tree | 65cea70b6c7e6d6ecfe5d9a7c308cd26f4453319 /tools/lib | |
parent | 5eefe17c7ae41bac4d2d281669e8357a10f4d5a4 (diff) | |
download | linux-b63b3c490eeeedd324e194929bd0aa8ba553f875.tar.bz2 |
libbpf: Add bpf_program__set_insns function
Adding bpf_program__set_insns that allows to set new instructions
for a BPF 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.
One of the users of this new API will be perf's internal BPF prologue
generation.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510074659.2557731-2-jolsa@kernel.org
Diffstat (limited to 'tools/lib')
-rw-r--r-- | tools/lib/bpf/libbpf.c | 22 | ||||
-rw-r--r-- | tools/lib/bpf/libbpf.h | 18 | ||||
-rw-r--r-- | tools/lib/bpf/libbpf.map | 1 |
3 files changed, 41 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0e74fae25896..4867a930628b 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6860,6 +6860,8 @@ 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) { @@ -8788,6 +8790,26 @@ 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) { diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index a1fb91810378..21984dcd6dbe 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -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. diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 80819e26a976..008da8db1d94 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -449,6 +449,7 @@ LIBBPF_0.8.0 { bpf_program__attach_kprobe_multi_opts; bpf_program__attach_trace_opts; bpf_program__attach_usdt; + bpf_program__set_insns; libbpf_register_prog_handler; libbpf_unregister_prog_handler; } LIBBPF_0.7.0; |