tools/bpf: sync kernel header bpf.h and add bpf_task_fd_query in libbpf

Sync kernel header bpf.h to tools/include/uapi/linux/bpf.h and
implement bpf_task_fd_query() in libbpf. The test programs
in samples/bpf and tools/testing/selftests/bpf, and later bpftool
will use this libbpf function to query kernel.

Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2 files changed, 26 insertions, 0 deletions

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 442b4cdfeb71..9ddc89dae962 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -643,3 +643,26 @@ retry:
 
         return fd;
 }
+
+int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len,
+                      __u32 *prog_id, __u32 *fd_type, __u64 *probe_offset,
+                      __u64 *probe_addr)
+{
+        union bpf_attr attr = {};
+        int err;
+
+        attr.task_fd_query.pid = pid;
+        attr.task_fd_query.fd = fd;
+        attr.task_fd_query.flags = flags;
+        attr.task_fd_query.buf = ptr_to_u64(buf);
+        attr.task_fd_query.buf_len = *buf_len;
+
+        err = sys_bpf(BPF_TASK_FD_QUERY, &attr, sizeof(attr));
+        *buf_len = attr.task_fd_query.buf_len;
+        *prog_id = attr.task_fd_query.prog_id;
+        *fd_type = attr.task_fd_query.fd_type;
+        *probe_offset = attr.task_fd_query.probe_offset;
+        *probe_addr = attr.task_fd_query.probe_addr;
+
+        return err;
+}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index d12344f66d4e..0639a30a457d 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -107,4 +107,7 @@ int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags,
 int bpf_raw_tracepoint_open(const char *name, int prog_fd);
 int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size,
                  bool do_log);
+int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len,
+                      __u32 *prog_id, __u32 *fd_type, __u64 *probe_offset,
+                      __u64 *probe_addr);
 #endif