SystemConfiguration.fproj/SCDNotifierWait.c

   1 /*
   2  * Copyright (c) 2000, 2001, 2004, 2006, 2009-2011, 2015-2017, 2019 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 "SCDynamicStoreInternal.h"
  35 #include "config.h"             /* MiG generated file */
  36 #include <mach/mach_error.h>
  37
  38
  39 static mach_msg_id_t
  40 waitForMachMessage(mach_port_t port)
  41 {
  42         union {
  43                 u_int8_t                buf[sizeof(mach_msg_empty_t) + MAX_TRAILER_SIZE];
  44                 mach_msg_empty_rcv_t    msg;
  45         } notify_msg;
  46         kern_return_t   status;
  47
  48         status = mach_msg(&notify_msg.msg.header,       /* msg */
  49                           MACH_RCV_MSG,                 /* options */
  50                           0,                            /* send_size */
  51                           sizeof(notify_msg),           /* rcv_size */
  52                           port,                         /* rcv_name */
  53                           MACH_MSG_TIMEOUT_NONE,        /* timeout */
  54                           MACH_PORT_NULL);              /* notify */
  55         if (status != KERN_SUCCESS) {
  56                 SC_log(LOG_NOTICE, "mach_msg() failed: %s", mach_error_string(status));
  57                 return -1;
  58         }
  59
  60         return notify_msg.msg.header.msgh_id;
  61 }
  62
  63
  64 Boolean
  65 SCDynamicStoreNotifyWait(SCDynamicStoreRef store)
  66 {
  67         SCDynamicStorePrivateRef        storePrivate = (SCDynamicStorePrivateRef)store;
  68         kern_return_t                   status;
  69         mach_port_t                     port;
  70         mach_port_t                     oldNotify;
  71         int                             sc_status;
  72         mach_msg_id_t                   msgid;
  73
  74         if (store == NULL) {
  75                 /* sorry, you must provide a session */
  76                 _SCErrorSet(kSCStatusNoStoreSession);
  77                 return FALSE;
  78         }
  79
  80         if (storePrivate->server == MACH_PORT_NULL) {
  81                 /* sorry, you must have an open session to play */
  82                 _SCErrorSet(kSCStatusNoStoreServer);
  83                 return FALSE;
  84         }
  85
  86         if (storePrivate->notifyStatus != NotifierNotRegistered) {
  87                 /* sorry, you can only have one notification registered at once */
  88                 _SCErrorSet(kSCStatusNotifierActive);
  89                 return FALSE;
  90         }
  91
  92         /* Allocating port (for server response) */
  93         status = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &port);
  94         if (status != KERN_SUCCESS) {
  95                 SC_log(LOG_ERR, "mach_port_allocate() failed: %s", mach_error_string(status));
  96                 _SCErrorSet(status);
  97                 return FALSE;
  98         }
  99
 100         status = mach_port_insert_right(mach_task_self(),
 101                                         port,
 102                                         port,
 103                                         MACH_MSG_TYPE_MAKE_SEND);
 104         if (status != KERN_SUCCESS) {
 105                 /*
 106                  * We can't insert a send right into our own port!  This should
 107                  * only happen if someone stomped on OUR port (so let's leave
 108                  * the port alone).
 109                  */
 110                 SC_log(LOG_NOTICE, "mach_port_insert_right() failed: %s", mach_error_string(status));
 111                 _SCErrorSet(status);
 112                 return FALSE;
 113         }
 114
 115         /* Request a notification when/if the server dies */
 116         status = mach_port_request_notification(mach_task_self(),
 117                                                 port,
 118                                                 MACH_NOTIFY_NO_SENDERS,
 119                                                 1,
 120                                                 port,
 121                                                 MACH_MSG_TYPE_MAKE_SEND_ONCE,
 122                                                 &oldNotify);
 123         if (status != KERN_SUCCESS) {
 124                 /*
 125                  * We can't request a notification for our own port!  This should
 126                  * only happen if someone stomped on OUR port (so let's leave
 127                  * the port alone).
 128                  */
 129                 SC_log(LOG_NOTICE, "mach_port_request_notification() failed: %s", mach_error_string(status));
 130                 _SCErrorSet(status);
 131                 return FALSE;
 132         }
 133
 134         if (oldNotify != MACH_PORT_NULL) {
 135                 SC_log(LOG_NOTICE, "oldNotify != MACH_PORT_NULL");
 136         }
 137
 138     retry :
 139
 140         status = notifyviaport(storePrivate->server,
 141                                port,
 142                                0,
 143                                (int *)&sc_status);
 144
 145         if (__SCDynamicStoreCheckRetryAndHandleError(store,
 146                                                      status,
 147                                                      &sc_status,
 148                                                      "SCDynamicStoreNotifyWait notifyviaport()")) {
 149                 goto retry;
 150         }
 151
 152         if (status != KERN_SUCCESS) {
 153                 if ((status == MACH_SEND_INVALID_DEST) || (status == MIG_SERVER_DIED)) {
 154                         /* remove the send right that we tried (but failed) to pass to the server */
 155                         (void) mach_port_deallocate(mach_task_self(), port);
 156                 }
 157
 158                 /* remove our receive right  */
 159                 (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE, -1);
 160         }
 161
 162         if (sc_status != kSCStatusOK) {
 163                 _SCErrorSet(sc_status);
 164                 return FALSE;
 165         }
 166
 167         /* set notifier active */
 168         storePrivate->notifyStatus = Using_NotifierWait;
 169
 170         msgid = waitForMachMessage(port);
 171
 172         /* set notifier inactive */
 173         storePrivate->notifyStatus = NotifierNotRegistered;
 174
 175         if (msgid == MACH_NOTIFY_NO_SENDERS) {
 176                 /* the server closed the notifier port */
 177 #ifdef  DEBUG
 178                 SC_log(LOG_DEBUG, "notifier port closed, port %d", port);
 179 #endif  /* DEBUG */
 180                 _SCErrorSet(kSCStatusNoStoreServer);
 181                 return FALSE;
 182         }
 183
 184         if (msgid == -1) {
 185                 /* one of the mach routines returned an error */
 186 #ifdef  DEBUG
 187                 SC_log(LOG_DEBUG, "communication with server failed, remove port right %d", port);
 188 #endif  /* DEBUG */
 189                 (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE , -1);
 190                 _SCErrorSet(kSCStatusNoStoreServer);
 191                 return FALSE;
 192         }
 193
 194         // something changed, cancelling notification request
 195         status = notifycancel(storePrivate->server,
 196                               (int *)&sc_status);
 197
 198         if (__SCDynamicStoreCheckRetryAndHandleError(store,
 199                                                      status,
 200                                                      &sc_status,
 201                                                      "SCDynamicStoreNotifyWait notifycancel()")) {
 202                 sc_status = kSCStatusOK;
 203         }
 204
 205         /* remove our receive right  */
 206         (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE , -1);
 207
 208         if (sc_status != kSCStatusOK) {
 209                 _SCErrorSet(sc_status);
 210                 return FALSE;
 211         }
 212
 213         return TRUE;
 214 }