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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2020 Facebook
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
char _license[] SEC("license") = "GPL";
struct sample {
int pid;
int seq;
long value;
char comm[16];
};
struct ringbuf_map {
__uint(type, BPF_MAP_TYPE_RINGBUF);
/* libbpf will adjust to valid page size */
__uint(max_entries, 1000);
} ringbuf1 SEC(".maps"),
ringbuf2 SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, 4);
__type(key, int);
__array(values, struct ringbuf_map);
} ringbuf_arr SEC(".maps") = {
.values = {
[0] = &ringbuf1,
[2] = &ringbuf2,
},
};
struct {
__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
__uint(max_entries, 1);
__type(key, int);
__array(values, struct ringbuf_map);
} ringbuf_hash SEC(".maps") = {
.values = {
[0] = &ringbuf1,
},
};
/* inputs */
int pid = 0;
int target_ring = 0;
long value = 0;
/* outputs */
long total = 0;
long dropped = 0;
long skipped = 0;
SEC("tp/syscalls/sys_enter_getpgid")
int test_ringbuf(void *ctx)
{
int cur_pid = bpf_get_current_pid_tgid() >> 32;
struct sample *sample;
void *rb;
if (cur_pid != pid)
return 0;
rb = bpf_map_lookup_elem(&ringbuf_arr, &target_ring);
if (!rb) {
skipped += 1;
return 1;
}
sample = bpf_ringbuf_reserve(rb, sizeof(*sample), 0);
if (!sample) {
dropped += 1;
return 1;
}
sample->pid = pid;
bpf_get_current_comm(sample->comm, sizeof(sample->comm));
sample->value = value;
sample->seq = total;
total += 1;
bpf_ringbuf_submit(sample, 0);
return 0;
}
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