From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
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_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 <roberto.sassu@xxxxxxxxxx>
---
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 f43e8c8afbd3..f3d89a2bdb50 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -1003,19 +1003,29 @@ 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_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_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 35c0cc6ed71b..04813e5ac309 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -382,6 +382,8 @@ LIBBPF_API int bpf_map_get_fd_by_id(__u32 id);
LIBBPF_API int bpf_btf_get_fd_by_id_opts(__u32 id,
const struct bpf_get_fd_opts *opts);
LIBBPF_API int bpf_btf_get_fd_by_id(__u32 id);
+LIBBPF_API int bpf_link_get_fd_by_id_opts(__u32 id,
+ const struct bpf_get_fd_opts *opts);
LIBBPF_API int bpf_link_get_fd_by_id(__u32 id);
LIBBPF_API int bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 7db2d963cb55..e52816e2555a 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;
} LIBBPF_1.0.0;
--
2.25.1
