bsd/net/init.c

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30
  31 #include <kern/kalloc.h>
  32 #include <libkern/OSAtomic.h>
  33 #include <sys/errno.h>
  34 #include <net/init.h>
  35 #include <libkern/libkern.h>
  36 #include <string.h>
  37
  38 struct init_list_entry {
  39         struct init_list_entry  *next;
  40         net_init_func_ptr               func;
  41 };
  42
  43 #define LIST_RAN ((struct init_list_entry*)0xffffffff)
  44 static struct init_list_entry   *list_head = 0;
  45
  46 errno_t
  47 net_init_add(
  48         net_init_func_ptr init_func)
  49 {
  50         struct init_list_entry  *entry;
  51
  52         if (init_func == 0) {
  53                 return EINVAL;
  54         }
  55
  56         /* Check if we've already started */
  57         if (list_head == LIST_RAN) {
  58                 return EALREADY;
  59         }
  60
  61         entry = kalloc(sizeof(*entry));
  62         if (entry == 0) {
  63                 printf("net_init_add: no memory\n");
  64                 return ENOMEM;
  65         }
  66
  67         bzero(entry, sizeof(*entry));
  68         entry->func = init_func;
  69
  70         do {
  71                 entry->next = list_head;
  72
  73                 if (entry->next == LIST_RAN) {
  74                         /* List already ran, cleanup and call the function */
  75                         kfree(entry, sizeof(*entry));
  76                         return EALREADY;
  77                 }
  78         } while(!OSCompareAndSwap((UInt32)entry->next, (UInt32)entry,
  79                                                           (UInt32*)&list_head));
  80
  81         return 0;
  82 }
  83
  84 __private_extern__ void
  85 net_init_run(void)
  86 {
  87         struct init_list_entry  *backward_head = 0;
  88         struct init_list_entry  *forward_head = 0;
  89         struct init_list_entry  *current = 0;
  90
  91         /*
  92          * Grab the list, replacing the head with 0xffffffff to indicate
  93          * that we've already run.
  94          */
  95         do {
  96                 backward_head = list_head;
  97         } while (!OSCompareAndSwap((UInt32)backward_head, (UInt32)LIST_RAN,
  98                                                            (UInt32*)&list_head));
  99
 100         /* Reverse the order of the list */
 101         while (backward_head != 0) {
 102                 current = backward_head;
 103                 backward_head = current->next;
 104                 current->next = forward_head;
 105                 forward_head = current;
 106         }
 107
 108         /* Call each function pointer registered */
 109         while (forward_head != 0) {
 110                 current = forward_head;
 111                 forward_head = current->next;
 112                 current->func();
 113                 kfree(current, sizeof(*current));
 114         }
 115 }