1/*
2 * Copyright (c) 2024 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16#include <stdio.h>
17#include <syscall.h>
18#include <assert.h>
19#include <syscall_hooks.h>
20
21#include "libc.h"
22#include "pthread_impl.h"
23
24#define HIJACK_SYSCALL_MAX  1024
25
26volatile const char *g_syscall_hooks_table __attribute__((aligned(8))) = NULL;
27volatile void *g_syscall_hooks_entry __attribute__((aligned(8))) = NULL;
28
29/*
30 * @brief
31 *     reset == 0: g_syscall_hooks_table and g_syscall_hooks_entry will be the function
32 *                 input parameters hooks_table and hooks_entry.
33 *     reset != 0: g_syscall_hooks_table and g_syscall_hooks_entry will be default values
34 *
35 * @param
36 *     hooks_table: pointer to a syscall table
37 *     hooks_entry: pointer to svc0_entry
38 *
39 * @return
40 *     -EINVAL: input parameters are invalid
41 *     -EPERM: operation not allowed
42 *     0: set_syscall_hooks success
43*/
44
45int set_syscall_hooks(const char *hooks_table, int table_len, void *hooks_entry, int reset, int **tid_addr)
46{
47	int ret = 0;
48
49	if (reset == 0) {
50		if (hooks_table == NULL || hooks_entry == NULL || tid_addr == NULL ||
51			table_len < HIJACK_SYSCALL_MAX) {
52				ret = -EINVAL;
53			}
54	}
55
56	if (ret == 0) {
57		__tl_lock();
58		if (!libc.threads_minus_1) {
59			if (reset) {
60				g_syscall_hooks_entry = NULL;
61				g_syscall_hooks_table = NULL;
62			} else {
63				g_syscall_hooks_entry = hooks_entry;
64				g_syscall_hooks_table = hooks_table;
65			}
66			*tid_addr = &__thread_list_lock;
67		} else {
68			ret = -EPERM;
69		}
70		__tl_unlock();
71	}
72
73	return ret;
74}