151ee71d3SDave Marchevsky // SPDX-License-Identifier: GPL-2.0
251ee71d3SDave Marchevsky /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
351ee71d3SDave Marchevsky
451ee71d3SDave Marchevsky #include <linux/bpf.h>
551ee71d3SDave Marchevsky #include <bpf/bpf_helpers.h>
651ee71d3SDave Marchevsky #include "bpf_misc.h"
751ee71d3SDave Marchevsky
851ee71d3SDave Marchevsky char _license[] SEC("license") = "GPL";
951ee71d3SDave Marchevsky
1051ee71d3SDave Marchevsky struct sample {
1151ee71d3SDave Marchevsky int pid;
1251ee71d3SDave Marchevsky int seq;
1351ee71d3SDave Marchevsky long value;
1451ee71d3SDave Marchevsky char comm[16];
1551ee71d3SDave Marchevsky };
1651ee71d3SDave Marchevsky
1751ee71d3SDave Marchevsky struct {
1851ee71d3SDave Marchevsky __uint(type, BPF_MAP_TYPE_RINGBUF);
1951ee71d3SDave Marchevsky } ringbuf SEC(".maps");
2051ee71d3SDave Marchevsky
2151ee71d3SDave Marchevsky struct {
2251ee71d3SDave Marchevsky __uint(type, BPF_MAP_TYPE_HASH);
2351ee71d3SDave Marchevsky __uint(max_entries, 1000);
2451ee71d3SDave Marchevsky __type(key, struct sample);
2551ee71d3SDave Marchevsky __type(value, int);
2651ee71d3SDave Marchevsky } hash_map SEC(".maps");
2751ee71d3SDave Marchevsky
2851ee71d3SDave Marchevsky /* inputs */
2951ee71d3SDave Marchevsky int pid = 0;
3051ee71d3SDave Marchevsky
3151ee71d3SDave Marchevsky /* inner state */
3251ee71d3SDave Marchevsky long seq = 0;
3351ee71d3SDave Marchevsky
3451ee71d3SDave Marchevsky SEC("fentry/" SYS_PREFIX "sys_getpgid")
test_ringbuf_mem_map_key(void * ctx)3551ee71d3SDave Marchevsky int test_ringbuf_mem_map_key(void *ctx)
3651ee71d3SDave Marchevsky {
3751ee71d3SDave Marchevsky int cur_pid = bpf_get_current_pid_tgid() >> 32;
3851ee71d3SDave Marchevsky struct sample *sample, sample_copy;
3951ee71d3SDave Marchevsky int *lookup_val;
4051ee71d3SDave Marchevsky
4151ee71d3SDave Marchevsky if (cur_pid != pid)
4251ee71d3SDave Marchevsky return 0;
4351ee71d3SDave Marchevsky
4451ee71d3SDave Marchevsky sample = bpf_ringbuf_reserve(&ringbuf, sizeof(*sample), 0);
4551ee71d3SDave Marchevsky if (!sample)
4651ee71d3SDave Marchevsky return 0;
4751ee71d3SDave Marchevsky
4851ee71d3SDave Marchevsky sample->pid = pid;
4951ee71d3SDave Marchevsky bpf_get_current_comm(sample->comm, sizeof(sample->comm));
5051ee71d3SDave Marchevsky sample->seq = ++seq;
5151ee71d3SDave Marchevsky sample->value = 42;
5251ee71d3SDave Marchevsky
5351ee71d3SDave Marchevsky /* test using 'sample' (PTR_TO_MEM | MEM_ALLOC) as map key arg
5451ee71d3SDave Marchevsky */
5551ee71d3SDave Marchevsky lookup_val = (int *)bpf_map_lookup_elem(&hash_map, sample);
56*c8ed6685SAndrii Nakryiko __sink(lookup_val);
5751ee71d3SDave Marchevsky
5851ee71d3SDave Marchevsky /* workaround - memcpy is necessary so that verifier doesn't
5951ee71d3SDave Marchevsky * complain with:
6051ee71d3SDave Marchevsky * verifier internal error: more than one arg with ref_obj_id R3
6151ee71d3SDave Marchevsky * when trying to do bpf_map_update_elem(&hash_map, sample, &sample->seq, BPF_ANY);
6251ee71d3SDave Marchevsky *
6351ee71d3SDave Marchevsky * Since bpf_map_lookup_elem above uses 'sample' as key, test using
6451ee71d3SDave Marchevsky * sample field as value below
6551ee71d3SDave Marchevsky */
6651ee71d3SDave Marchevsky __builtin_memcpy(&sample_copy, sample, sizeof(struct sample));
6751ee71d3SDave Marchevsky bpf_map_update_elem(&hash_map, &sample_copy, &sample->seq, BPF_ANY);
6851ee71d3SDave Marchevsky
6951ee71d3SDave Marchevsky bpf_ringbuf_submit(sample, 0);
7051ee71d3SDave Marchevsky return 0;
7151ee71d3SDave Marchevsky }
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