1/* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me> 2 * 3 * This program is free software; you can redistribute it and/or 4 * modify it under the terms of version 2 of the GNU General Public 5 * License as published by the Free Software Foundation. 6 */ 7 8#include "vmlinux.h" 9#include <linux/version.h> 10#include <bpf/bpf_helpers.h> 11#include <bpf/bpf_tracing.h> 12#include <bpf/bpf_core_read.h> 13 14struct { 15 __uint(type, BPF_MAP_TYPE_CGROUP_ARRAY); 16 __uint(key_size, sizeof(u32)); 17 __uint(value_size, sizeof(u32)); 18 __uint(max_entries, 1); 19} cgroup_map SEC(".maps"); 20 21struct { 22 __uint(type, BPF_MAP_TYPE_ARRAY); 23 __type(key, u32); 24 __type(value, u64); 25 __uint(max_entries, 1); 26} perf_map SEC(".maps"); 27 28/* Writes the last PID that called sync to a map at index 0 */ 29SEC("ksyscall/sync") 30int BPF_KSYSCALL(bpf_prog1) 31{ 32 u64 pid = bpf_get_current_pid_tgid(); 33 int idx = 0; 34 35 if (!bpf_current_task_under_cgroup(&cgroup_map, 0)) 36 return 0; 37 38 bpf_map_update_elem(&perf_map, &idx, &pid, BPF_ANY); 39 return 0; 40} 41 42char _license[] SEC("license") = "GPL"; 43u32 _version SEC("version") = LINUX_VERSION_CODE; 44