1 files changed, 43 insertions, 0 deletions
diff --git a/samples/bpf/test_current_task_under_cgroup_kern.c b/samples/bpf/test_current_task_under_cgroup_kern.c
new file mode 100644
index 000000000000..86b28d7d6c99
--- /dev/null
+++ b/samples/bpf/test_current_task_under_cgroup_kern.c
@@ -0,0 +1,43 @@
+/* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me>
+ *
+ * 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 <linux/ptrace.h>
+#include <uapi/linux/bpf.h>
+#include <linux/version.h>
+#include "bpf_helpers.h"
+#include <uapi/linux/utsname.h>
+
+struct bpf_map_def SEC("maps") cgroup_map = {
+	.type			= BPF_MAP_TYPE_CGROUP_ARRAY,
+	.key_size		= sizeof(u32),
+	.value_size		= sizeof(u32),
+	.max_entries	= 1,
+};
+
+struct bpf_map_def SEC("maps") perf_map = {
+	.type			= BPF_MAP_TYPE_ARRAY,
+	.key_size		= sizeof(u32),
+	.value_size		= sizeof(u64),
+	.max_entries	= 1,
+};
+
+/* Writes the last PID that called sync to a map at index 0 */
+SEC("kprobe/sys_sync")
+int bpf_prog1(struct pt_regs *ctx)
+{
+	u64 pid = bpf_get_current_pid_tgid();
+	int idx = 0;
+
+	if (!bpf_current_task_under_cgroup(&cgroup_map, 0))
+		return 0;
+
+	bpf_map_update_elem(&perf_map, &idx, &pid, BPF_ANY);
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;