40 lines
693 B
C
40 lines
693 B
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/* Copyright (c) 2021 Hengqi Chen */
|
|
|
|
#include "vmlinux.h"
|
|
#include <bpf/bpf_helpers.h>
|
|
#include <bpf/bpf_tracing.h>
|
|
|
|
const volatile pid_t my_pid = 0;
|
|
int value = 0;
|
|
|
|
SEC("raw_tp/sys_enter")
|
|
int tailcall_1(void *ctx)
|
|
{
|
|
value = 42;
|
|
return 0;
|
|
}
|
|
|
|
struct {
|
|
__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
|
|
__uint(max_entries, 2);
|
|
__uint(key_size, sizeof(__u32));
|
|
__array(values, int (void *));
|
|
} prog_array_init SEC(".maps") = {
|
|
.values = {
|
|
[1] = (void *)&tailcall_1,
|
|
},
|
|
};
|
|
|
|
SEC("raw_tp/sys_enter")
|
|
int entry(void *ctx)
|
|
{
|
|
pid_t pid = bpf_get_current_pid_tgid() >> 32;
|
|
|
|
if (pid != my_pid)
|
|
return 0;
|
|
|
|
bpf_tail_call(ctx, &prog_array_init, 1);
|
|
return 0;
|
|
}
|