SystemConfiguration.fproj/SCDNotifierWait.c

   1 /*
   2  * Copyright (c) 2000, 2001, 2004, 2006, 2009-2011, 2015 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  * Modification History
  26  *
  27  * June 1, 2001                 Allan Nathanson <ajn@apple.com>
  28  * - public API conversion
  29  *
  30  * March 31, 2000               Allan Nathanson <ajn@apple.com>
  31  * - initial revision
  32  */
  33
  34 #include <mach/mach.h>
  35 #include <mach/mach_error.h>
  36
  37 #include <SystemConfiguration/SystemConfiguration.h>
  38 #include <SystemConfiguration/SCPrivate.h>
  39 #include "SCDynamicStoreInternal.h"
  40 #include "config.h"             /* MiG generated file */
  41
  42 static mach_msg_id_t
  43 waitForMachMessage(mach_port_t port)
  44 {
  45         union {
  46                 u_int8_t                buf[sizeof(mach_msg_empty_t) + MAX_TRAILER_SIZE];
  47                 mach_msg_empty_rcv_t    msg;
  48         } notify_msg;
  49         kern_return_t   status;
  50
  51         status = mach_msg(&notify_msg.msg.header,       /* msg */
  52                           MACH_RCV_MSG,                 /* options */
  53                           0,                            /* send_size */
  54                           sizeof(notify_msg),           /* rcv_size */
  55                           port,                         /* rcv_name */
  56                           MACH_MSG_TIMEOUT_NONE,        /* timeout */
  57                           MACH_PORT_NULL);              /* notify */
  58         if (status != KERN_SUCCESS) {
  59                 SC_log(LOG_NOTICE, "mach_msg() failed: %s", mach_error_string(status));
  60                 return -1;
  61         }
  62
  63         return notify_msg.msg.header.msgh_id;
  64 }
  65
  66
  67 Boolean
  68 SCDynamicStoreNotifyWait(SCDynamicStoreRef store)
  69 {
  70         SCDynamicStorePrivateRef        storePrivate = (SCDynamicStorePrivateRef)store;
  71         kern_return_t                   status;
  72         mach_port_t                     port;
  73         mach_port_t                     oldNotify;
  74         int                             sc_status;
  75         mach_msg_id_t                   msgid;
  76
  77         if (store == NULL) {
  78                 /* sorry, you must provide a session */
  79                 _SCErrorSet(kSCStatusNoStoreSession);
  80                 return FALSE;
  81         }
  82
  83         if (storePrivate->server == MACH_PORT_NULL) {
  84                 /* sorry, you must have an open session to play */
  85                 _SCErrorSet(kSCStatusNoStoreServer);
  86                 return FALSE;
  87         }
  88
  89         if (storePrivate->notifyStatus != NotifierNotRegistered) {
  90                 /* sorry, you can only have one notification registered at once */
  91                 _SCErrorSet(kSCStatusNotifierActive);
  92                 return FALSE;
  93         }
  94
  95         /* Allocating port (for server response) */
  96         status = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &port);
  97         if (status != KERN_SUCCESS) {
  98                 SC_log(LOG_ERR, "mach_port_allocate() failed: %s", mach_error_string(status));
  99                 _SCErrorSet(status);
 100                 return FALSE;
 101         }
 102
 103         status = mach_port_insert_right(mach_task_self(),
 104                                         port,
 105                                         port,
 106                                         MACH_MSG_TYPE_MAKE_SEND);
 107         if (status != KERN_SUCCESS) {
 108                 /*
 109                  * We can't insert a send right into our own port!  This should
 110                  * only happen if someone stomped on OUR port (so let's leave
 111                  * the port alone).
 112                  */
 113                 SC_log(LOG_NOTICE, "mach_port_insert_right() failed: %s", mach_error_string(status));
 114                 _SCErrorSet(status);
 115                 return FALSE;
 116         }
 117
 118         /* Request a notification when/if the server dies */
 119         status = mach_port_request_notification(mach_task_self(),
 120                                                 port,
 121                                                 MACH_NOTIFY_NO_SENDERS,
 122                                                 1,
 123                                                 port,
 124                                                 MACH_MSG_TYPE_MAKE_SEND_ONCE,
 125                                                 &oldNotify);
 126         if (status != KERN_SUCCESS) {
 127                 /*
 128                  * We can't request a notification for our own port!  This should
 129                  * only happen if someone stomped on OUR port (so let's leave
 130                  * the port alone).
 131                  */
 132                 SC_log(LOG_NOTICE, "mach_port_request_notification() failed: %s", mach_error_string(status));
 133                 _SCErrorSet(status);
 134                 return FALSE;
 135         }
 136
 137         if (oldNotify != MACH_PORT_NULL) {
 138                 SC_log(LOG_NOTICE, "oldNotify != MACH_PORT_NULL");
 139         }
 140
 141     retry :
 142
 143         status = notifyviaport(storePrivate->server,
 144                                port,
 145                                0,
 146                                (int *)&sc_status);
 147
 148         if (__SCDynamicStoreCheckRetryAndHandleError(store,
 149                                                      status,
 150                                                      &sc_status,
 151                                                      "SCDynamicStoreNotifyWait notifyviaport()")) {
 152                 goto retry;
 153         }
 154
 155         if (status != KERN_SUCCESS) {
 156                 if ((status == MACH_SEND_INVALID_DEST) || (status == MIG_SERVER_DIED)) {
 157                         /* remove the send right that we tried (but failed) to pass to the server */
 158                         (void) mach_port_deallocate(mach_task_self(), port);
 159                 }
 160
 161                 /* remove our receive right  */
 162                 (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE, -1);
 163         }
 164
 165         if (sc_status != kSCStatusOK) {
 166                 _SCErrorSet(sc_status);
 167                 return FALSE;
 168         }
 169
 170         /* set notifier active */
 171         storePrivate->notifyStatus = Using_NotifierWait;
 172
 173         msgid = waitForMachMessage(port);
 174
 175         /* set notifier inactive */
 176         storePrivate->notifyStatus = NotifierNotRegistered;
 177
 178         if (msgid == MACH_NOTIFY_NO_SENDERS) {
 179                 /* the server closed the notifier port */
 180 #ifdef  DEBUG
 181                 SC_log(LOG_DEBUG, "notifier port closed, port %d", port);
 182 #endif  /* DEBUG */
 183                 _SCErrorSet(kSCStatusNoStoreServer);
 184                 return FALSE;
 185         }
 186
 187         if (msgid == -1) {
 188                 /* one of the mach routines returned an error */
 189 #ifdef  DEBUG
 190                 SC_log(LOG_DEBUG, "communication with server failed, remove port right %d", port);
 191 #endif  /* DEBUG */
 192                 (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE , -1);
 193                 _SCErrorSet(kSCStatusNoStoreServer);
 194                 return FALSE;
 195         }
 196
 197         // something changed, cancelling notification request
 198         status = notifycancel(storePrivate->server,
 199                               (int *)&sc_status);
 200
 201         if (__SCDynamicStoreCheckRetryAndHandleError(store,
 202                                                      status,
 203                                                      &sc_status,
 204                                                      "SCDynamicStoreNotifyWait notifycancel()")) {
 205                 sc_status = kSCStatusOK;
 206         }
 207
 208         /* remove our receive right  */
 209         (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE , -1);
 210
 211         if (sc_status != kSCStatusOK) {
 212                 _SCErrorSet(sc_status);
 213                 return FALSE;
 214         }
 215
 216         return TRUE;
 217 }