1// SPDX-License-Identifier: GPL-2.0
 2/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
 3
 4#include <vmlinux.h>
 5#include <bpf/bpf_helpers.h>
 6#include "uptr_test_common.h"
 7
 8struct task_struct *bpf_task_from_pid(s32 pid) __ksym;
 9void bpf_task_release(struct task_struct *p) __ksym;
10void bpf_cgroup_release(struct cgroup *cgrp) __ksym;
11
12struct {
13	__uint(type, BPF_MAP_TYPE_TASK_STORAGE);
14	__uint(map_flags, BPF_F_NO_PREALLOC);
15	__type(key, int);
16	__type(value, struct value_type);
17} datamap SEC(".maps");
18
19pid_t target_pid = 0;
20pid_t parent_pid = 0;
21
22SEC("tp_btf/sys_enter")
23int on_enter(__u64 *ctx)
24{
25	struct task_struct *task, *data_task;
26	struct value_type *ptr;
27	struct user_data *udata;
28	struct cgroup *cgrp;
29
30	task = bpf_get_current_task_btf();
31	if (task->pid != target_pid)
32		return 0;
33
34	data_task = bpf_task_from_pid(parent_pid);
35	if (!data_task)
36		return 0;
37
38	ptr = bpf_task_storage_get(&datamap, data_task, 0, 0);
39	bpf_task_release(data_task);
40	if (!ptr)
41		return 0;
42
43	cgrp = bpf_kptr_xchg(&ptr->cgrp, NULL);
44	if (cgrp) {
45		int lvl = cgrp->level;
46
47		bpf_cgroup_release(cgrp);
48		return lvl;
49	}
50
51	udata = ptr->udata;
52	if (!udata || udata->result)
53		return 0;
54	udata->result = MAGIC_VALUE + udata->a + udata->b;
55
56	udata = ptr->nested.udata;
57	if (udata && !udata->nested_result)
58		udata->nested_result = udata->result;
59
60	return 0;
61}
62
63char _license[] SEC("license") = "GPL";