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1// SPDX-License-Identifier: GPL-2.02// Copyright (c) 2020 Facebook3 4#include <linux/bpf.h>5#include <bpf/bpf_helpers.h>6 7char _license[] SEC("license") = "GPL";8 9struct sample {10 int pid;11 int seq;12 long value;13 char comm[16];14};15 16struct ringbuf_map {17 __uint(type, BPF_MAP_TYPE_RINGBUF);18 /* libbpf will adjust to valid page size */19 __uint(max_entries, 1000);20} ringbuf1 SEC(".maps"),21 ringbuf2 SEC(".maps");22 23struct {24 __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);25 __uint(max_entries, 4);26 __type(key, int);27 __array(values, struct ringbuf_map);28} ringbuf_arr SEC(".maps") = {29 .values = {30 [0] = &ringbuf1,31 [2] = &ringbuf2,32 },33};34 35struct {36 __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);37 __uint(max_entries, 1);38 __type(key, int);39 __array(values, struct ringbuf_map);40} ringbuf_hash SEC(".maps") = {41 .values = {42 [0] = &ringbuf1,43 },44};45 46/* inputs */47int pid = 0;48int target_ring = 0;49long value = 0;50 51/* outputs */52long total = 0;53long dropped = 0;54long skipped = 0;55 56SEC("tp/syscalls/sys_enter_getpgid")57int test_ringbuf(void *ctx)58{59 int cur_pid = bpf_get_current_pid_tgid() >> 32;60 struct sample *sample;61 void *rb;62 63 if (cur_pid != pid)64 return 0;65 66 rb = bpf_map_lookup_elem(&ringbuf_arr, &target_ring);67 if (!rb) {68 skipped += 1;69 return 1;70 }71 72 sample = bpf_ringbuf_reserve(rb, sizeof(*sample), 0);73 if (!sample) {74 dropped += 1;75 return 1;76 }77 78 sample->pid = pid;79 bpf_get_current_comm(sample->comm, sizeof(sample->comm));80 sample->value = value;81 82 sample->seq = total;83 total += 1;84 85 bpf_ringbuf_submit(sample, 0);86 87 return 0;88}89