bsd/net/init.c

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22
  23 #include <kern/kalloc.h>
  24 #include <libkern/OSAtomic.h>
  25 #include <sys/errno.h>
  26 #include <net/init.h>
  27 #include <libkern/libkern.h>
  28 #include <string.h>
  29
  30 struct init_list_entry {
  31         struct init_list_entry  *next;
  32         net_init_func_ptr               func;
  33 };
  34
  35 #define LIST_RAN ((struct init_list_entry*)0xffffffff)
  36 static struct init_list_entry   *list_head = 0;
  37
  38 errno_t
  39 net_init_add(
  40         net_init_func_ptr init_func)
  41 {
  42         struct init_list_entry  *entry;
  43
  44         if (init_func == 0) {
  45                 return EINVAL;
  46         }
  47
  48         /* Check if we've already started */
  49         if (list_head == LIST_RAN) {
  50                 return EALREADY;
  51         }
  52
  53         entry = kalloc(sizeof(*entry));
  54         if (entry == 0) {
  55                 printf("net_init_add: no memory\n");
  56                 return ENOMEM;
  57         }
  58
  59         bzero(entry, sizeof(*entry));
  60         entry->func = init_func;
  61
  62         do {
  63                 entry->next = list_head;
  64
  65                 if (entry->next == LIST_RAN) {
  66                         /* List already ran, cleanup and call the function */
  67                         kfree(entry, sizeof(*entry));
  68                         return EALREADY;
  69                 }
  70         } while(!OSCompareAndSwap((UInt32)entry->next, (UInt32)entry,
  71                                                           (UInt32*)&list_head));
  72
  73         return 0;
  74 }
  75
  76 __private_extern__ void
  77 net_init_run(void)
  78 {
  79         struct init_list_entry  *backward_head = 0;
  80         struct init_list_entry  *forward_head = 0;
  81         struct init_list_entry  *current = 0;
  82
  83         /*
  84          * Grab the list, replacing the head with 0xffffffff to indicate
  85          * that we've already run.
  86          */
  87         do {
  88                 backward_head = list_head;
  89         } while (!OSCompareAndSwap((UInt32)backward_head, (UInt32)LIST_RAN,
  90                                                            (UInt32*)&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(current, sizeof(*current));
 106         }
 107 }