SystemConfiguration.fproj/SCDNotifierWait.c

   1 /*
   2  * Copyright (c) 2000, 2001, 2004, 2006, 2009-2011, 2015, 2016 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         os_activity_scope(storePrivate->activity);
 139
 140     retry :
 141
 142         status = notifyviaport(storePrivate->server,
 143                                port,
 144                                0,
 145                                (int *)&sc_status);
 146
 147         if (__SCDynamicStoreCheckRetryAndHandleError(store,
 148                                                      status,
 149                                                      &sc_status,
 150                                                      "SCDynamicStoreNotifyWait notifyviaport()")) {
 151                 goto retry;
 152         }
 153
 154         if (status != KERN_SUCCESS) {
 155                 if ((status == MACH_SEND_INVALID_DEST) || (status == MIG_SERVER_DIED)) {
 156                         /* remove the send right that we tried (but failed) to pass to the server */
 157                         (void) mach_port_deallocate(mach_task_self(), port);
 158                 }
 159
 160                 /* remove our receive right  */
 161                 (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE, -1);
 162         }
 163
 164         if (sc_status != kSCStatusOK) {
 165                 _SCErrorSet(sc_status);
 166                 return FALSE;
 167         }
 168
 169         /* set notifier active */
 170         storePrivate->notifyStatus = Using_NotifierWait;
 171
 172         msgid = waitForMachMessage(port);
 173
 174         /* set notifier inactive */
 175         storePrivate->notifyStatus = NotifierNotRegistered;
 176
 177         if (msgid == MACH_NOTIFY_NO_SENDERS) {
 178                 /* the server closed the notifier port */
 179 #ifdef  DEBUG
 180                 SC_log(LOG_DEBUG, "notifier port closed, port %d", port);
 181 #endif  /* DEBUG */
 182                 _SCErrorSet(kSCStatusNoStoreServer);
 183                 return FALSE;
 184         }
 185
 186         if (msgid == -1) {
 187                 /* one of the mach routines returned an error */
 188 #ifdef  DEBUG
 189                 SC_log(LOG_DEBUG, "communication with server failed, remove port right %d", port);
 190 #endif  /* DEBUG */
 191                 (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE , -1);
 192                 _SCErrorSet(kSCStatusNoStoreServer);
 193                 return FALSE;
 194         }
 195
 196         os_activity_scope(storePrivate->activity);
 197
 198         // something changed, cancelling notification request
 199         status = notifycancel(storePrivate->server,
 200                               (int *)&sc_status);
 201
 202         if (__SCDynamicStoreCheckRetryAndHandleError(store,
 203                                                      status,
 204                                                      &sc_status,
 205                                                      "SCDynamicStoreNotifyWait notifycancel()")) {
 206                 sc_status = kSCStatusOK;
 207         }
 208
 209         /* remove our receive right  */
 210         (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE , -1);
 211
 212         if (sc_status != kSCStatusOK) {
 213                 _SCErrorSet(sc_status);
 214                 return FALSE;
 215         }
 216
 217         return TRUE;
 218 }