bpf: add a test case for syscalls/sys_{enter|exit}_* tracepoints

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 62 insertions, 0 deletions

diff --git a/samples/bpf/syscall_tp_kern.c b/samples/bpf/syscall_tp_kern.c
new file mode 100644
index 000000000000..9149c524d279
--- /dev/null
+++ b/samples/bpf/syscall_tp_kern.c
@@ -0,0 +1,62 @@
+/* Copyright (c) 2017 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <uapi/linux/bpf.h>
+#include "bpf_helpers.h"
+
+struct syscalls_enter_open_args {
+	unsigned long long unused;
+	long syscall_nr;
+	long filename_ptr;
+	long flags;
+	long mode;
+};
+
+struct syscalls_exit_open_args {
+	unsigned long long unused;
+	long syscall_nr;
+	long ret;
+};
+
+struct bpf_map_def SEC("maps") enter_open_map = {
+	.type = BPF_MAP_TYPE_ARRAY,
+	.key_size = sizeof(u32),
+	.value_size = sizeof(u32),
+	.max_entries = 1,
+};
+
+struct bpf_map_def SEC("maps") exit_open_map = {
+	.type = BPF_MAP_TYPE_ARRAY,
+	.key_size = sizeof(u32),
+	.value_size = sizeof(u32),
+	.max_entries = 1,
+};
+
+static __always_inline void count(void *map)
+{
+	u32 key = 0;
+	u32 *value, init_val = 1;
+
+	value = bpf_map_lookup_elem(map, &key);
+	if (value)
+		*value += 1;
+	else
+		bpf_map_update_elem(map, &key, &init_val, BPF_NOEXIST);
+}
+
+SEC("tracepoint/syscalls/sys_enter_open")
+int trace_enter_open(struct syscalls_enter_open_args *ctx)
+{
+	count((void *)&enter_open_map);
+	return 0;
+}
+
+SEC("tracepoint/syscalls/sys_exit_open")
+int trace_enter_exit(struct syscalls_exit_open_args *ctx)
+{
+	count((void *)&exit_open_map);
+	return 0;
+}