xnu-792.tar.gz

[apple/xnu.git] / bsd / net / init.c

diff --git a/bsd/net/init.c b/bsd/net/init.c
new file mode 100644 (file)
index 0000000..82c2882
--- /dev/null
+++ b/bsd/net/init.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
+ * 
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+#include <kern/kalloc.h>
+#include <libkern/OSAtomic.h>
+#include <sys/errno.h>
+#include <net/init.h>
+#include <libkern/libkern.h>
+#include <string.h>
+
+struct init_list_entry {
+       struct init_list_entry  *next;
+       net_init_func_ptr               func;
+};
+
+#define LIST_RAN ((struct init_list_entry*)0xffffffff)
+static struct init_list_entry  *list_head = 0;
+
+errno_t
+net_init_add(
+       net_init_func_ptr init_func)
+{
+       struct init_list_entry  *entry;
+       
+       if (init_func == 0) {
+               return EINVAL;
+       }
+       
+       /* Check if we've already started */
+       if (list_head == LIST_RAN) {
+               return EALREADY;
+       }
+       
+       entry = kalloc(sizeof(*entry));
+       if (entry == 0) {
+               printf("net_init_add: no memory\n");
+               return ENOMEM;
+       }
+       
+       bzero(entry, sizeof(*entry));
+       entry->func = init_func;
+       
+       do {
+               entry->next = list_head;
+               
+               if (entry->next == LIST_RAN) {
+                       /* List already ran, cleanup and call the function */
+                       kfree(entry, sizeof(*entry));
+                       return EALREADY;
+               }
+       } while(!OSCompareAndSwap((UInt32)entry->next, (UInt32)entry,
+                                                         (UInt32*)&list_head));
+       
+       return 0;
+}
+
+__private_extern__ void
+net_init_run(void)
+{
+       struct init_list_entry  *backward_head = 0;
+       struct init_list_entry  *forward_head = 0;
+       struct init_list_entry  *current = 0;
+       
+       /*
+        * Grab the list, replacing the head with 0xffffffff to indicate
+        * that we've already run.
+        */
+       do {
+               backward_head = list_head;
+       } while (!OSCompareAndSwap((UInt32)backward_head, (UInt32)LIST_RAN,
+                                                          (UInt32*)&list_head));
+       
+       /* Reverse the order of the list */
+       while (backward_head != 0) {
+               current = backward_head;
+               backward_head = current->next;
+               current->next = forward_head;
+               forward_head = current;
+       }
+       
+       /* Call each function pointer registered */
+       while (forward_head != 0) {
+               current = forward_head;
+               forward_head = current->next;
+               current->func();
+               kfree(current, sizeof(*current));
+       }
+}