1 /*
2 * Copyright (c) 2000-2021 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28
29 #include <kern/kalloc.h>
30 #include <libkern/OSAtomic.h>
31 #include <sys/errno.h>
32 #include <net/init.h>
33 #include <libkern/libkern.h>
34 #include <string.h>
35
36 struct init_list_entry {
37 struct init_list_entry *next;
38 net_init_func_ptr func;
39 };
40
41 #define LIST_RAN ((struct init_list_entry*)0xffffffff)
42 static struct init_list_entry *list_head = 0;
43
44 errno_t
net_init_add(net_init_func_ptr init_func)45 net_init_add(
46 net_init_func_ptr init_func)
47 {
48 struct init_list_entry *entry;
49
50 if (init_func == 0) {
51 return EINVAL;
52 }
53
54 /* Check if we've already started */
55 if (list_head == LIST_RAN) {
56 return EALREADY;
57 }
58
59 entry = kalloc_type(struct init_list_entry,
60 Z_WAITOK | Z_ZERO | Z_NOFAIL);
61
62 entry->func = init_func;
63
64 do {
65 entry->next = list_head;
66
67 if (entry->next == LIST_RAN) {
68 /* List already ran, cleanup and call the function */
69 kfree_type(struct init_list_entry, entry);
70 return EALREADY;
71 }
72 } while (!OSCompareAndSwapPtr(entry->next, entry, &list_head));
73
74 return 0;
75 }
76
77 __private_extern__ void
net_init_run(void)78 net_init_run(void)
79 {
80 struct init_list_entry *backward_head = 0;
81 struct init_list_entry *forward_head = 0;
82 struct init_list_entry *current = 0;
83
84 /*
85 * Grab the list, replacing the head with 0xffffffff to indicate
86 * that we've already run.
87 */
88 do {
89 backward_head = list_head;
90 } while (!OSCompareAndSwapPtr(backward_head, LIST_RAN, &list_head));
91
92 /* Reverse the order of the list */
93 while (backward_head != 0) {
94 current = backward_head;
95 backward_head = current->next;
96 current->next = forward_head;
97 forward_head = current;
98 }
99
100 /* Call each function pointer registered */
101 while (forward_head != 0) {
102 current = forward_head;
103 forward_head = current->next;
104 current->func();
105 kfree_type(struct init_list_entry, current);
106 }
107 }
108