usr/src/lib/udapl/libdat/common/dat_init.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2002-2003, Network Appliance, Inc. All rights reserved.
  24  */
  25
  26 /*
  27  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
  28  * Use is subject to license terms.
  29  */
  30
  31 #pragma ident   "%Z%%M% %I%     %E% SMI"
  32
  33
  34 /*
  35  *
  36  * MODULE: dat_init.c
  37  *
  38  * PURPOSE: DAT registry implementation for uDAPL
  39  * Description: init and fini functions for DAT module.
  40  *
  41  * $Id: dat_init.c,v 1.12 2003/07/09 11:26:06 hobie16 Exp $
  42  */
  43
  44 #include "dat_init.h"
  45
  46 #include "dat_dr.h"
  47 #include "dat_osd.h"
  48
  49 #ifndef DAT_NO_STATIC_REGISTRY
  50 #include "dat_sr.h"
  51 #endif
  52
  53
  54 /*
  55  *
  56  * Global Variables
  57  *
  58  */
  59
  60 /*
  61  * Ideally, the following two rules could be enforced:
  62  *
  63  * - The DAT Registry's initialization function is executed before that
  64  *   of any DAT Providers and hence all calls into the registry occur
  65  *   after the registry module is initialized.
  66  *
  67  * - The DAT Registry's deinitialization function is executed after that
  68  *   of any DAT Providers and hence all calls into the registry occur
  69  *   before the registry module is deinitialized.
  70  *
  71  * However, on many platforms few guarantees are provided regarding the
  72  * order in which modules initialization and deinitialization functions
  73  * are invoked.
  74  *
  75  * To understand why these rules are difficult to enforce using only
  76  * features common to all platforms, consider the Linux platform. The order
  77  * in which Linux shared libraries are loaded into a process's address space
  78  * is undefined. When a DAT consumer explicitly links to DAT provider
  79  * libraries, the order in which library initialization and deinitialization
  80  * functions are invoked becomes important. For example if the DAPL provider
  81  * calls dat_registry_add_provider() before the registry has been initialized,
  82  * an error will occur.
  83  *
  84  * We assume that modules are loaded with a single thread. Given
  85  * this assumption, we can use a simple state variable to determine
  86  * the state of the DAT registry.
  87  */
  88
  89 static DAT_MODULE_STATE         g_module_state = DAT_MODULE_STATE_UNINITIALIZED;
  90
  91
  92 /*
  93  * Function: dat_module_get_state
  94  */
  95
  96 DAT_MODULE_STATE
  97 dat_module_get_state(void)
  98 {
  99         return (g_module_state);
 100 }
 101
 102
 103 /*
 104  *  Function: dat_init
 105  */
 106
 107 void
 108 dat_init(void)
 109 {
 110         if (DAT_MODULE_STATE_UNINITIALIZED == g_module_state) {
 111         /*
 112          * update the module state flag immediately in case there
 113          * is a recursive call to dat_init().
 114          */
 115                 g_module_state = DAT_MODULE_STATE_INITIALIZING;
 116
 117                 dat_os_dbg_init();
 118
 119                 dat_os_dbg_print(DAT_OS_DBG_TYPE_GENERIC,
 120                     "DAT Registry: Started (dat_init)\n");
 121
 122 #ifndef DAT_NO_STATIC_REGISTRY
 123                 (void) dat_sr_init();
 124 #endif
 125                 (void) dat_dr_init();
 126
 127                 g_module_state = DAT_MODULE_STATE_INITIALIZED;
 128         }
 129 }
 130
 131
 132 /*
 133  * Function: dat_fini
 134  */
 135
 136 void
 137 dat_fini(void)
 138 {
 139         if (DAT_MODULE_STATE_INITIALIZED == g_module_state) {
 140                 g_module_state = DAT_MODULE_STATE_DEINITIALIZING;
 141
 142                 (void) dat_dr_fini();
 143 #ifndef DAT_NO_STATIC_REGISTRY
 144                 (void) dat_sr_fini();
 145 #endif
 146                 dat_os_dbg_print(DAT_OS_DBG_TYPE_GENERIC,
 147                     "DAT Registry: Stopped (dat_fini)\n");
 148
 149                 g_module_state = DAT_MODULE_STATE_DEINITIALIZED;
 150         }
 151 }
 152
 153
 154 /*
 155  * Local variables:
 156  *  c-indent-level: 4
 157  *  c-basic-offset: 4
 158  *  tab-width: 8
 159  * End:
 160  */