44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
/* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#include "vmlinux.h"
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#include <linux/version.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_core_read.h>
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struct {
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__uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
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__uint(key_size, sizeof(u32));
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__uint(value_size, sizeof(u32));
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__uint(max_entries, 1);
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} cgroup_map SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, u32);
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__type(value, u64);
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__uint(max_entries, 1);
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} perf_map SEC(".maps");
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/* Writes the last PID that called sync to a map at index 0 */
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SEC("ksyscall/sync")
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int BPF_KSYSCALL(bpf_prog1)
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{
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u64 pid = bpf_get_current_pid_tgid();
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int idx = 0;
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if (!bpf_current_task_under_cgroup(&cgroup_map, 0))
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return 0;
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bpf_map_update_elem(&perf_map, &idx, &pid, BPF_ANY);
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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u32 _version SEC("version") = LINUX_VERSION_CODE;
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