bsd/net/init.c

   1 /*
   2  * Copyright (c) 2000-2004 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
  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(sizeof(*entry));
  60         if (entry == 0) {
  61                 printf("net_init_add: no memory\n");
  62                 return ENOMEM;
  63         }
  64
  65         bzero(entry, sizeof(*entry));
  66         entry->func = init_func;
  67
  68         do {
  69                 entry->next = list_head;
  70
  71                 if (entry->next == LIST_RAN) {
  72                         /* List already ran, cleanup and call the function */
  73                         kfree(entry, sizeof(*entry));
  74                         return EALREADY;
  75                 }
  76         } while(!OSCompareAndSwap((UInt32)entry->next, (UInt32)entry,
  77                                                           (UInt32*)&list_head));
  78
  79         return 0;
  80 }
  81
  82 __private_extern__ void
  83 net_init_run(void)
  84 {
  85         struct init_list_entry  *backward_head = 0;
  86         struct init_list_entry  *forward_head = 0;
  87         struct init_list_entry  *current = 0;
  88
  89         /*
  90          * Grab the list, replacing the head with 0xffffffff to indicate
  91          * that we've already run.
  92          */
  93         do {
  94                 backward_head = list_head;
  95         } while (!OSCompareAndSwap((UInt32)backward_head, (UInt32)LIST_RAN,
  96                                                            (UInt32*)&list_head));
  97
  98         /* Reverse the order of the list */
  99         while (backward_head != 0) {
 100                 current = backward_head;
 101                 backward_head = current->next;
 102                 current->next = forward_head;
 103                 forward_head = current;
 104         }
 105
 106         /* Call each function pointer registered */
 107         while (forward_head != 0) {
 108                 current = forward_head;
 109                 forward_head = current->next;
 110                 current->func();
 111                 kfree(current, sizeof(*current));
 112         }
 113 }