tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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";