From 97c8f9dd5db839f2387785ee936d0a5b257b31d3 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Thu, 6 Oct 2022 13:07:35 +0200 Subject: [PATCH] libbpf: Introduce bpf_link_get_fd_by_id_opts() Introduce bpf_link_get_fd_by_id_opts(), for symmetry with bpf_map_get_fd_by_id_opts(), to let the caller pass the newly introduced data structure bpf_get_fd_by_id_opts. Keep the existing bpf_link_get_fd_by_id(), and call bpf_link_get_fd_by_id_opts() with NULL as opts argument, to prevent setting open_flags. Currently, the kernel does not support non-zero open_flags for bpf_link_get_fd_by_id_opts(), and a call with them will result in an error returned by the bpf() system call. The caller should always pass zero open_flags. Signed-off-by: Roberto Sassu Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20221006110736.84253-6-roberto.sassu@huaweicloud.com --- tools/lib/bpf/bpf.c | 12 +++++++++++- tools/lib/bpf/bpf.h | 2 ++ tools/lib/bpf/libbpf.map | 1 + 3 files changed, 14 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index b95fed0..9aff98f 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -1004,19 +1004,29 @@ int bpf_btf_get_fd_by_id(__u32 id) return bpf_btf_get_fd_by_id_opts(id, NULL); } -int bpf_link_get_fd_by_id(__u32 id) +int bpf_link_get_fd_by_id_opts(__u32 id, + const struct bpf_get_fd_by_id_opts *opts) { const size_t attr_sz = offsetofend(union bpf_attr, open_flags); union bpf_attr attr; int fd; + if (!OPTS_VALID(opts, bpf_get_fd_by_id_opts)) + return libbpf_err(-EINVAL); + memset(&attr, 0, attr_sz); attr.link_id = id; + attr.open_flags = OPTS_GET(opts, open_flags, 0); fd = sys_bpf_fd(BPF_LINK_GET_FD_BY_ID, &attr, attr_sz); return libbpf_err_errno(fd); } +int bpf_link_get_fd_by_id(__u32 id) +{ + return bpf_link_get_fd_by_id_opts(id, NULL); +} + int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len) { const size_t attr_sz = offsetofend(union bpf_attr, info); diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 4b48730..a112e0e 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -383,6 +383,8 @@ LIBBPF_API int bpf_btf_get_fd_by_id(__u32 id); LIBBPF_API int bpf_btf_get_fd_by_id_opts(__u32 id, const struct bpf_get_fd_by_id_opts *opts); LIBBPF_API int bpf_link_get_fd_by_id(__u32 id); +LIBBPF_API int bpf_link_get_fd_by_id_opts(__u32 id, + const struct bpf_get_fd_by_id_opts *opts); LIBBPF_API int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len); struct bpf_prog_query_opts { diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 7011d5e..71bf569 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -372,6 +372,7 @@ LIBBPF_1.0.0 { LIBBPF_1.1.0 { global: bpf_btf_get_fd_by_id_opts; + bpf_link_get_fd_by_id_opts; bpf_map_get_fd_by_id_opts; bpf_prog_get_fd_by_id_opts; user_ring_buffer__discard; -- 2.7.4