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1// SPDX-License-Identifier: GPL-2.02/* Copyright (c) 2021 Facebook */3 4#include <linux/bpf.h>5#define BPF_NO_GLOBAL_DATA6#include <bpf/bpf_helpers.h>7 8char LICENSE[] SEC("license") = "GPL";9 10struct {11 __uint(type, BPF_MAP_TYPE_ARRAY);12 __type(key, int);13 __type(value, int);14 __uint(max_entries, 1);15} my_pid_map SEC(".maps");16 17struct {18 __uint(type, BPF_MAP_TYPE_ARRAY);19 __type(key, int);20 __type(value, int);21 __uint(max_entries, 1);22} res_map SEC(".maps");23 24volatile int my_pid_var = 0;25volatile int res_var = 0;26 27SEC("tp/raw_syscalls/sys_enter")28int handle_legacy(void *ctx)29{30 int zero = 0, *my_pid, cur_pid, *my_res;31 32 my_pid = bpf_map_lookup_elem(&my_pid_map, &zero);33 if (!my_pid)34 return 1;35 36 cur_pid = bpf_get_current_pid_tgid() >> 32;37 if (cur_pid != *my_pid)38 return 1;39 40 my_res = bpf_map_lookup_elem(&res_map, &zero);41 if (!my_res)42 return 1;43 44 if (*my_res == 0)45 /* use bpf_printk() in combination with BPF_NO_GLOBAL_DATA to46 * force .rodata.str1.1 section that previously caused47 * problems on old kernels due to libbpf always tried to48 * create a global data map for it49 */50 bpf_printk("Legacy-case bpf_printk test, pid %d\n", cur_pid);51 *my_res = 1;52 53 return *my_res;54}55 56SEC("tp/raw_syscalls/sys_enter")57int handle_modern(void *ctx)58{59 int cur_pid;60 61 cur_pid = bpf_get_current_pid_tgid() >> 32;62 if (cur_pid != my_pid_var)63 return 1;64 65 if (res_var == 0)66 /* we need bpf_printk() to validate libbpf logic around unused67 * global maps and legacy kernels; see comment in handle_legacy()68 */69 bpf_printk("Modern-case bpf_printk test, pid %d\n", cur_pid);70 res_var = 1;71 72 return res_var;73}74