1// SPDX-License-Identifier: GPL-2.0 2// Copyright (c) 2019 Facebook 3 4#include <linux/bpf.h> 5#include <stdint.h> 6#include "bpf_helpers.h" 7 8char _license[] SEC("license") = "GPL"; 9 10static volatile struct data { 11 char in[256]; 12 char out[256]; 13} data; 14 15struct core_reloc_misc_output { 16 int a, b, c; 17}; 18 19struct core_reloc_misc___a { 20 int a1; 21 int a2; 22}; 23 24struct core_reloc_misc___b { 25 int b1; 26 int b2; 27}; 28 29/* fixed two first members, can be extended with new fields */ 30struct core_reloc_misc_extensible { 31 int a; 32 int b; 33}; 34 35SEC("raw_tracepoint/sys_enter") 36int test_core_misc(void *ctx) 37{ 38 struct core_reloc_misc___a *in_a = (void *)&data.in; 39 struct core_reloc_misc___b *in_b = (void *)&data.in; 40 struct core_reloc_misc_extensible *in_ext = (void *)&data.in; 41 struct core_reloc_misc_output *out = (void *)&data.out; 42 43 /* record two different relocations with the same accessor string */ 44 if (BPF_CORE_READ(&out->a, &in_a->a1) || /* accessor: 0:0 */ 45 BPF_CORE_READ(&out->b, &in_b->b1)) /* accessor: 0:0 */ 46 return 1; 47 48 /* Validate relocations capture array-only accesses for structs with 49 * fixed header, but with potentially extendable tail. This will read 50 * first 4 bytes of 2nd element of in_ext array of potentially 51 * variably sized struct core_reloc_misc_extensible. */ 52 if (BPF_CORE_READ(&out->c, &in_ext[2])) /* accessor: 2 */ 53 return 1; 54 55 return 0; 56} 57 58