1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ 3 4 #include <linux/bpf.h> 5 #include <bpf/bpf_helpers.h> 6 #include "bpf_misc.h" 7 8 char _license[] SEC("license") = "GPL"; 9 10 struct sample { 11 int pid; 12 int seq; 13 long value; 14 char comm[16]; 15 }; 16 17 struct { 18 __uint(type, BPF_MAP_TYPE_RINGBUF); 19 } ringbuf SEC(".maps"); 20 21 struct { 22 __uint(type, BPF_MAP_TYPE_HASH); 23 __uint(max_entries, 1000); 24 __type(key, struct sample); 25 __type(value, int); 26 } hash_map SEC(".maps"); 27 28 /* inputs */ 29 int pid = 0; 30 31 /* inner state */ 32 long seq = 0; 33 34 SEC("fentry/" SYS_PREFIX "sys_getpgid") 35 int test_ringbuf_mem_map_key(void *ctx) 36 { 37 int cur_pid = bpf_get_current_pid_tgid() >> 32; 38 struct sample *sample, sample_copy; 39 int *lookup_val; 40 41 if (cur_pid != pid) 42 return 0; 43 44 sample = bpf_ringbuf_reserve(&ringbuf, sizeof(*sample), 0); 45 if (!sample) 46 return 0; 47 48 sample->pid = pid; 49 bpf_get_current_comm(sample->comm, sizeof(sample->comm)); 50 sample->seq = ++seq; 51 sample->value = 42; 52 53 /* test using 'sample' (PTR_TO_MEM | MEM_ALLOC) as map key arg 54 */ 55 lookup_val = (int *)bpf_map_lookup_elem(&hash_map, sample); 56 57 /* workaround - memcpy is necessary so that verifier doesn't 58 * complain with: 59 * verifier internal error: more than one arg with ref_obj_id R3 60 * when trying to do bpf_map_update_elem(&hash_map, sample, &sample->seq, BPF_ANY); 61 * 62 * Since bpf_map_lookup_elem above uses 'sample' as key, test using 63 * sample field as value below 64 */ 65 __builtin_memcpy(&sample_copy, sample, sizeof(struct sample)); 66 bpf_map_update_elem(&hash_map, &sample_copy, &sample->seq, BPF_ANY); 67 68 bpf_ringbuf_submit(sample, 0); 69 return 0; 70 } 71