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1// SPDX-License-Identifier: GPL-2.02/* Copyright (C) 2023. Huawei Technologies Co., Ltd */3#include <linux/bpf.h>4#include <time.h>5#include <bpf/bpf_helpers.h>6 7#include "bpf_misc.h"8 9struct inner_map_type {10 __uint(type, BPF_MAP_TYPE_ARRAY);11 __uint(key_size, 4);12 __uint(value_size, 4);13 __uint(max_entries, 1);14} inner_map SEC(".maps");15 16struct {17 __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);18 __type(key, int);19 __type(value, int);20 __uint(max_entries, 1);21 __array(values, struct inner_map_type);22} outer_array_map SEC(".maps") = {23 .values = {24 [0] = &inner_map,25 },26};27 28struct {29 __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);30 __type(key, int);31 __type(value, int);32 __uint(max_entries, 1);33 __array(values, struct inner_map_type);34} outer_htab_map SEC(".maps") = {35 .values = {36 [0] = &inner_map,37 },38};39 40char _license[] SEC("license") = "GPL";41 42int tgid = 0;43 44static int acc_map_in_map(void *outer_map)45{46 int i, key, value = 0xdeadbeef;47 void *inner_map;48 49 if ((bpf_get_current_pid_tgid() >> 32) != tgid)50 return 0;51 52 /* Find nonexistent inner map */53 key = 1;54 inner_map = bpf_map_lookup_elem(outer_map, &key);55 if (inner_map)56 return 0;57 58 /* Find the old inner map */59 key = 0;60 inner_map = bpf_map_lookup_elem(outer_map, &key);61 if (!inner_map)62 return 0;63 64 /* Wait for the old inner map to be replaced */65 for (i = 0; i < 2048; i++)66 bpf_map_update_elem(inner_map, &key, &value, 0);67 68 return 0;69}70 71SEC("?kprobe/" SYS_PREFIX "sys_getpgid")72int access_map_in_array(void *ctx)73{74 return acc_map_in_map(&outer_array_map);75}76 77SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")78int sleepable_access_map_in_array(void *ctx)79{80 return acc_map_in_map(&outer_array_map);81}82 83SEC("?kprobe/" SYS_PREFIX "sys_getpgid")84int access_map_in_htab(void *ctx)85{86 return acc_map_in_map(&outer_htab_map);87}88 89SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")90int sleepable_access_map_in_htab(void *ctx)91{92 return acc_map_in_map(&outer_htab_map);93}94