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_lookup(struct cgroup *cgrp)
 31{
 32	bpf_cgrp_storage_delete(&map_a, cgrp);
 33	bpf_cgrp_storage_delete(&map_b, cgrp);
 34}
 35
 36SEC("fentry/bpf_local_storage_lookup")
 37int BPF_PROG(on_lookup)
 38{
 39	struct task_struct *task = bpf_get_current_task_btf();
 40	struct cgroup *cgrp;
 41
 42	if (is_cgroup1) {
 43		cgrp = bpf_task_get_cgroup1(task, target_hid);
 44		if (!cgrp)
 45			return 0;
 46
 47		__on_lookup(cgrp);
 48		bpf_cgroup_release(cgrp);
 49		return 0;
 50	}
 51
 52	__on_lookup(task->cgroups->dfl_cgrp);
 53	return 0;
 54}
 55
 56static void __on_update(struct cgroup *cgrp)
 57{
 58	long *ptr;
 59
 60	ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);
 61	if (ptr)
 62		*ptr += 1;
 63
 64	ptr = bpf_cgrp_storage_get(&map_b, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);
 65	if (ptr)
 66		*ptr += 1;
 67}
 68
 69SEC("fentry/bpf_local_storage_update")
 70int BPF_PROG(on_update)
 71{
 72	struct task_struct *task = bpf_get_current_task_btf();
 73	struct cgroup *cgrp;
 74
 75	if (is_cgroup1) {
 76		cgrp = bpf_task_get_cgroup1(task, target_hid);
 77		if (!cgrp)
 78			return 0;
 79
 80		__on_update(cgrp);
 81		bpf_cgroup_release(cgrp);
 82		return 0;
 83	}
 84
 85	__on_update(task->cgroups->dfl_cgrp);
 86	return 0;
 87}
 88
 89static void __on_enter(struct pt_regs *regs, long id, struct cgroup *cgrp)
 90{
 91	long *ptr;
 92
 93	ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);
 94	if (ptr)
 95		*ptr = 200;
 96
 97	ptr = bpf_cgrp_storage_get(&map_b, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);
 98	if (ptr)
 99		*ptr = 100;
100}
101
102SEC("tp_btf/sys_enter")
103int BPF_PROG(on_enter, struct pt_regs *regs, long id)
104{
105	struct task_struct *task = bpf_get_current_task_btf();
106	struct cgroup *cgrp;
107
108	if (is_cgroup1) {
109		cgrp = bpf_task_get_cgroup1(task, target_hid);
110		if (!cgrp)
111			return 0;
112
113		__on_enter(regs, id, cgrp);
114		bpf_cgroup_release(cgrp);
115		return 0;
116	}
117
118	__on_enter(regs, id, task->cgroups->dfl_cgrp);
119	return 0;
120}