1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
3
4#include "vmlinux.h"
5#include <bpf/bpf_helpers.h>
6#include <bpf/bpf_tracing.h>
7
8char _license[] SEC("license") = "GPL";
9
10struct {
11	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
12	__uint(map_flags, BPF_F_NO_PREALLOC);
13	__type(key, int);
14	__type(value, long);
15} map_a SEC(".maps");
16
17struct {
18	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
19	__uint(map_flags, BPF_F_NO_PREALLOC);
20	__type(key, int);
21	__type(value, long);
22} map_b SEC(".maps");
23
24int target_hid = 0;
25bool is_cgroup1 = 0;
26
27struct cgroup *bpf_task_get_cgroup1(struct task_struct *task, int hierarchy_id) __ksym;
28void bpf_cgroup_release(struct cgroup *cgrp) __ksym;
29
30static void __on_update(struct cgroup *cgrp)
31{
32	long *ptr;
33
34	ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);
35	if (ptr)
36		*ptr += 1;
37
38	ptr = bpf_cgrp_storage_get(&map_b, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);
39	if (ptr)
40		*ptr += 1;
41}
42
43SEC("fentry/bpf_local_storage_update")
44int BPF_PROG(on_update)
45{
46	struct task_struct *task = bpf_get_current_task_btf();
47	struct cgroup *cgrp;
48
49	if (is_cgroup1) {
50		cgrp = bpf_task_get_cgroup1(task, target_hid);
51		if (!cgrp)
52			return 0;
53
54		__on_update(cgrp);
55		bpf_cgroup_release(cgrp);
56		return 0;
57	}
58
59	__on_update(task->cgroups->dfl_cgrp);
60	return 0;
61}
62
63static void __on_enter(struct pt_regs *regs, long id, struct cgroup *cgrp)
64{
65	long *ptr;
66
67	ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);
68	if (ptr)
69		*ptr = 200;
70
71	ptr = bpf_cgrp_storage_get(&map_b, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);
72	if (ptr)
73		*ptr = 100;
74}
75
76SEC("tp_btf/sys_enter")
77int BPF_PROG(on_enter, struct pt_regs *regs, long id)
78{
79	struct task_struct *task = bpf_get_current_task_btf();
80	struct cgroup *cgrp;
81
82	if (is_cgroup1) {
83		cgrp = bpf_task_get_cgroup1(task, target_hid);
84		if (!cgrp)
85			return 0;
86
87		__on_enter(regs, id, cgrp);
88		bpf_cgroup_release(cgrp);
89		return 0;
90	}
91
92	__on_enter(regs, id, task->cgroups->dfl_cgrp);
93	return 0;
94}
95