[PATCH bpf-next v3 3/7] tools/bpf: sync kernel header bpf.h and add bpf_trace_event_query in libbpf

[Yonghong Song <yhs@fb.com>]

Sync kernel header bpf.h to tools/include/uapi/linux/bpf.h and
implement bpf_trace_event_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.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 tools/include/uapi/linux/bpf.h | 27 +++++++++++++++++++++++++++
 tools/lib/bpf/bpf.c            | 24 ++++++++++++++++++++++++
 tools/lib/bpf/bpf.h            |  3 +++
 3 files changed, 54 insertions(+)

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 97446bb..a602150 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -97,6 +97,7 @@ enum bpf_cmd {
 	BPF_RAW_TRACEPOINT_OPEN,
 	BPF_BTF_LOAD,
 	BPF_BTF_GET_FD_BY_ID,
+	BPF_TASK_FD_QUERY,
 };
 
 enum bpf_map_type {
@@ -379,6 +380,22 @@ union bpf_attr {
 		__u32		btf_log_size;
 		__u32		btf_log_level;
 	};
+
+	struct {
+		int		pid;		/* input: pid */
+		int		fd;		/* input: fd */
+		__u32		flags;		/* input: flags */
+		__u32		buf_len;	/* input: buf len */
+		__aligned_u64	buf;		/* input/output:
+						 *   tp_name for tracepoint
+						 *   symbol for kprobe
+						 *   filename for uprobe
+						 */
+		__u32		prog_id;	/* output: prod_id */
+		__u32		attach_info;	/* output: BPF_ATTACH_* */
+		__u64		probe_offset;	/* output: probe_offset */
+		__u64		probe_addr;	/* output: probe_addr */
+	} task_fd_query;
 } __attribute__((aligned(8)));
 
 /* The description below is an attempt at providing documentation to eBPF
@@ -2458,4 +2475,14 @@ struct bpf_fib_lookup {
 	__u8	dmac[6];     /* ETH_ALEN */
 };
 
+/* used by <task, fd> based query */
+enum {
+	BPF_ATTACH_RAW_TRACEPOINT,	/* tp name */
+	BPF_ATTACH_TRACEPOINT,		/* tp name */
+	BPF_ATTACH_KPROBE,		/* (symbol + offset) or addr */
+	BPF_ATTACH_KRETPROBE,		/* (symbol + offset) or addr */
+	BPF_ATTACH_UPROBE,		/* filename + offset */
+	BPF_ATTACH_URETPROBE,		/* filename + offset */
+};
+
 #endif /* _UAPI__LINUX_BPF_H__ */
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 6a8a000..da3f336 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -643,3 +643,27 @@ int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size,
 
 	return fd;
 }
+
+int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 buf_len,
+		      __u32 *prog_id, __u32 *attach_info,
+		      __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));
+	if (!err) {
+		*prog_id = attr.task_fd_query.prog_id;
+		*attach_info = attr.task_fd_query.attach_info;
+		*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 15bff77..9adfde6 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 *prog_info,
+		      __u64 *probe_offset, __u64 *probe_addr);
 #endif
-- 
2.9.5