Re: [PATCH v3 bpf-next 16/18] libbpf: Add support for attaching BPF programs to other BPF programs
From: Song Liu <hidden>
Date: 2019-11-08 20:24:40
Also in:
bpf
On Nov 7, 2019, at 10:40 PM, Alexei Starovoitov [off-list ref] wrote: Extend libbpf api to pass attach_prog_fd into bpf_object__open. Signed-off-by: Alexei Starovoitov <ast@kernel.org> ---
[...]
+static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
+{
+ struct bpf_prog_info_linear *info_linear;
+ struct bpf_prog_info *info;
+ struct btf *btf = NULL;
+ int err = -EINVAL;
+
+ info_linear = bpf_program__get_prog_info_linear(attach_prog_fd, 0);
+ if (IS_ERR_OR_NULL(info_linear)) {
+ pr_warn("failed get_prog_info_linear for FD %d\n",
+ attach_prog_fd);
+ return -EINVAL;
+ }
+ info = &info_linear->info;
+ if (!info->btf_id) {
+ pr_warn("The target program doesn't have BTF\n");
+ goto out;
+ }
+ if (btf__get_from_id(info->btf_id, &btf)) {
+ pr_warn("Failed to get BTF of the program\n");
+ goto out;
+ }
+ err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
+ btf__free(btf);
+ if (err <= 0) {
+ pr_warn("%s is not found in prog's BTF\n", name);
+ goto out;^^^ This goto doesn't really do much.
+ } +out: + free(info_linear); + return err; +}
Otherwise Acked-by: Song Liu <redacted>