On Thu, Nov 7, 2019 at 10:41 PM Alexei Starovoitov <ast@xxxxxxxxxx> wrote:
>
> Extend libbpf api to pass attach_prog_fd into bpf_object__open.
>
> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> ---
> tools/include/uapi/linux/bpf.h | 1 +
> tools/lib/bpf/bpf.c | 9 +++--
> tools/lib/bpf/bpf.h | 5 ++-
> tools/lib/bpf/libbpf.c | 65 +++++++++++++++++++++++++++++-----
> tools/lib/bpf/libbpf.h | 3 +-
> 5 files changed, 69 insertions(+), 14 deletions(-)
>
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 69c200e6e696..4842a134b202 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -425,6 +425,7 @@ union bpf_attr {
> __aligned_u64 line_info; /* line info */
> __u32 line_info_cnt; /* number of bpf_line_info records */
> __u32 attach_btf_id; /* in-kernel BTF type id to attach to */
> + __u32 attach_prog_fd; /* 0 to attach to vmlinux */
> };
>
> struct { /* anonymous struct used by BPF_OBJ_* commands */
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index b3e3e99a0f28..f805787c8efd 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -228,10 +228,14 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
> memset(&attr, 0, sizeof(attr));
> attr.prog_type = load_attr->prog_type;
> attr.expected_attach_type = load_attr->expected_attach_type;
> - if (attr.prog_type == BPF_PROG_TYPE_TRACING)
> + if (attr.prog_type == BPF_PROG_TYPE_TRACING) {
> attr.attach_btf_id = load_attr->attach_btf_id;
> - else
> + if (load_attr->attach_prog_fd)
> + attr.attach_prog_fd = load_attr->attach_prog_fd;
why the if? if it's zero, attr.attach_prog_fd will stay zero.
> + } else {
> attr.prog_ifindex = load_attr->prog_ifindex;
> + attr.kern_version = load_attr->kern_version;
> + }
> attr.insn_cnt = (__u32)load_attr->insns_cnt;
> attr.insns = ptr_to_u64(load_attr->insns);
> attr.license = ptr_to_u64(load_attr->license);
[...]
> CHECK_ERR(bpf_object__elf_init(obj), err, out);
> CHECK_ERR(bpf_object__check_endianness(obj), err, out);
> @@ -3927,10 +3934,12 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
> bpf_program__set_expected_attach_type(prog, attach_type);
> if (prog_type == BPF_PROG_TYPE_TRACING) {
> err = libbpf_attach_btf_id_by_name(prog->section_name,
> - attach_type);
> + attach_type,
> + attach_prog_fd);
libbpf_find_attach_btf_id seems like a better name at this point
> if (err <= 0)
> goto out;
> prog->attach_btf_id = err;
> + prog->attach_prog_fd = attach_prog_fd;
> }
> }
>
[...]
