From: Roberto Sassu roberto.sassu@huawei.com
Define a new data structure called bpf_get_fd_opts, with the member open_flags, to be used by callers of the _opts variants of bpf_*_get_fd_by_id() to specify the permissions needed for the file descriptor to be obtained.
Also, introduce bpf_map_get_fd_by_id_opts(), to let the caller pass a bpf_get_fd_opts structure.
Finally, keep the existing bpf_map_get_fd_by_id(), and call bpf_map_get_fd_by_id_opts() with NULL as opts argument, to request read-write permissions (current behavior).
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com --- tools/lib/bpf/bpf.c | 12 +++++++++++- tools/lib/bpf/bpf.h | 10 ++++++++++ tools/lib/bpf/libbpf.map | 1 + 3 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 1d49a0352836..4b03063edf1d 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -948,19 +948,29 @@ int bpf_prog_get_fd_by_id(__u32 id) return libbpf_err_errno(fd); }
-int bpf_map_get_fd_by_id(__u32 id) +int bpf_map_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.map_id = id; + attr.open_flags = OPTS_GET(opts, open_flags, 0);
fd = sys_bpf_fd(BPF_MAP_GET_FD_BY_ID, &attr, attr_sz); return libbpf_err_errno(fd); }
+int bpf_map_get_fd_by_id(__u32 id) +{ + return bpf_map_get_fd_by_id_opts(id, NULL); +} + int bpf_btf_get_fd_by_id(__u32 id) { const size_t attr_sz = offsetofend(union bpf_attr, open_flags); diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 9c50beabdd14..c60eda3c88ad 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -365,7 +365,17 @@ LIBBPF_API int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id); LIBBPF_API int bpf_map_get_next_id(__u32 start_id, __u32 *next_id); LIBBPF_API int bpf_btf_get_next_id(__u32 start_id, __u32 *next_id); LIBBPF_API int bpf_link_get_next_id(__u32 start_id, __u32 *next_id); + +struct bpf_get_fd_opts { + size_t sz; /* size of this struct for forward/backward compatibility */ + __u32 open_flags; /* permissions requested for the operation on fd */ + size_t :0; +}; +#define bpf_get_fd_opts__last_field open_flags + LIBBPF_API int bpf_prog_get_fd_by_id(__u32 id); +LIBBPF_API int bpf_map_get_fd_by_id_opts(__u32 id, + const struct bpf_get_fd_opts *opts); LIBBPF_API int bpf_map_get_fd_by_id(__u32 id); LIBBPF_API int bpf_btf_get_fd_by_id(__u32 id); LIBBPF_API int bpf_link_get_fd_by_id(__u32 id); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 04fab9f1fdd7..2e665b21d84f 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -371,6 +371,7 @@ LIBBPF_1.0.0 {
LIBBPF_1.1.0 { global: + bpf_map_get_fd_by_id_opts; user_ring_buffer__discard; user_ring_buffer__free; user_ring_buffer__new;