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/* 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 "vmlinux.h"
#include <linux/version.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_core_read.h>
struct {
__uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
__uint(key_size, sizeof(u32));
__uint(value_size, sizeof(u32));
__uint(max_entries, 1);
} cgroup_map SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, u32);
__type(value, u64);
__uint(max_entries, 1);
} perf_map SEC(".maps");
/* Writes the last PID that called sync to a map at index 0 */
SEC("ksyscall/sync")
int BPF_KSYSCALL(bpf_prog1)
{
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;
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