SystemConfiguration.fproj/helper/SCHelper_client.c

   1 /*
   2  * Copyright (c) 2005-2008, 2010, 2011, 2013, 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 #include <fcntl.h>
  25 #include <paths.h>
  26 #include <signal.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <unistd.h>
  31 #include <sys/param.h>
  32 #include <sys/types.h>
  33 #include <sys/socket.h>
  34 #include <sys/un.h>
  35 #include <sys/wait.h>
  36 #include <mach/mach.h>
  37 #include <mach/mach_error.h>
  38 #include <servers/bootstrap.h>
  39 #include <bootstrap_priv.h>
  40 #include <pthread.h>
  41
  42 #include "SCPreferencesInternal.h"
  43 #include "SCHelper_client.h"
  44 #include "helper.h"             // MiG generated file
  45
  46
  47 #define HELPER                                  "SCHelper"
  48 #define HELPER_LEN                              (sizeof(HELPER) - 1)
  49
  50 #define SUFFIX_SYM                              "~sym"
  51 #define SUFFIX_SYM_LEN                          (sizeof(SUFFIX_SYM) - 1)
  52
  53
  54 static pthread_mutex_t  _helper_lock            = PTHREAD_MUTEX_INITIALIZER;
  55 static mach_port_t      _helper_server          = MACH_PORT_NULL;
  56
  57
  58 static os_activity_t
  59 __SCHelperActivity()
  60 {
  61         static os_activity_t    activity        = NULL;
  62         static dispatch_once_t  once;
  63
  64         dispatch_once(&once, ^{
  65                 activity = os_activity_create("accessing SCPreferences [helper]",
  66                                               OS_ACTIVITY_CURRENT,
  67                                               OS_ACTIVITY_FLAG_DEFAULT);
  68         });
  69
  70         return activity;
  71 }
  72
  73
  74 static mach_port_t
  75 __SCHelperServerPort(kern_return_t *status)
  76 {
  77         mach_port_t     server  = MACH_PORT_NULL;
  78         char            *server_name;
  79
  80         server_name = getenv("SCHELPER_SERVER");
  81         if (!server_name) {
  82                 server_name = SCHELPER_SERVER;
  83         }
  84
  85 #ifdef  BOOTSTRAP_PRIVILEGED_SERVER
  86         *status = bootstrap_look_up2(bootstrap_port,
  87                                      server_name,
  88                                      &server,
  89                                      0,
  90                                      BOOTSTRAP_PRIVILEGED_SERVER);
  91 #else   // BOOTSTRAP_PRIVILEGED_SERVER
  92         *status = bootstrap_look_up(bootstrap_port, server_name, &server);
  93 #endif  // BOOTSTRAP_PRIVILEGED_SERVER
  94
  95         switch (*status) {
  96                 case BOOTSTRAP_SUCCESS :
  97                         /* service currently registered, "a good thing" (tm) */
  98                         return server;
  99                 case BOOTSTRAP_NOT_PRIVILEGED :
 100                         /* the service is not privileged */
 101                         break;
 102                 case BOOTSTRAP_UNKNOWN_SERVICE :
 103                         /* service not currently registered, try again later */
 104                         break;
 105                 default :
 106 #ifdef  DEBUG
 107                         SC_log(LOG_INFO, "bootstrap_look_up() failed: status=%s",
 108                                bootstrap_strerror(*status));
 109 #endif  /* DEBUG */
 110                         break;
 111         }
 112
 113         return MACH_PORT_NULL;
 114 }
 115
 116
 117 __private_extern__
 118 Boolean
 119 _SCHelperOpen(CFDataRef authorizationData, mach_port_t *helper_port)
 120 {
 121         kern_return_t           kr;
 122         Boolean                 ok;
 123         mach_port_t             server;
 124         uint32_t                status  = 0;
 125
 126         *helper_port = MACH_PORT_NULL;
 127
 128         // open a new session with the server
 129         server = _helper_server;
 130         while (TRUE) {
 131                 if (server != MACH_PORT_NULL) {
 132                         os_activity_scope(__SCHelperActivity());
 133
 134                         kr = helperinit(server,
 135                                         helper_port,
 136                                         &status);
 137                         if (kr == KERN_SUCCESS) {
 138                                 break;
 139                         }
 140
 141                         // our [cached] server port is not valid
 142                         if (kr != MACH_SEND_INVALID_DEST) {
 143                                 // if we got an unexpected error, don't retry
 144                                 status = kr;
 145                                 break;
 146                         }
 147                 }
 148
 149                 pthread_mutex_lock(&_helper_lock);
 150                 if (_helper_server != MACH_PORT_NULL) {
 151                         if (server == _helper_server) {
 152                                 // if the server we tried returned the error
 153                                 (void)mach_port_deallocate(mach_task_self(), _helper_server);
 154                                 _helper_server = __SCHelperServerPort(&kr);
 155                                 if (_helper_server == MACH_PORT_NULL) {
 156                                         status = kr;
 157                                 }
 158                         } else {
 159                                 // another thread has refreshed the SCHelper server port
 160                         }
 161                 } else {
 162                         _helper_server = __SCHelperServerPort(&kr);
 163                         if (_helper_server == MACH_PORT_NULL) {
 164                                 status = kr;
 165                         }
 166                 }
 167                 server = _helper_server;
 168                 pthread_mutex_unlock(&_helper_lock);
 169
 170                 if (server == MACH_PORT_NULL) {
 171                         // if SCHelper server not available
 172                         break;
 173                 }
 174         }
 175         __MACH_PORT_DEBUG(TRUE, "*** _SCHelperOpen", *helper_port);
 176
 177         if (*helper_port == MACH_PORT_NULL) {
 178                 SC_log(LOG_NOTICE, "could not contact \"" HELPER "\": %s",
 179                       SCErrorString(status));
 180                 return FALSE;
 181         }
 182
 183         ok = _SCHelperExec(*helper_port, SCHELPER_MSG_AUTH, authorizationData, &status, NULL);
 184         if (!ok) {
 185                 SC_log(LOG_NOTICE, "could not send authorization");
 186                 goto error;
 187         }
 188
 189         ok = (status == 0);
 190         if (!ok) {
 191                 SC_log(LOG_NOTICE, "could not start \"" HELPER "\", status = %u", status);
 192                 goto error;
 193         }
 194
 195         return TRUE;
 196
 197     error :
 198
 199         if (*helper_port != MACH_PORT_NULL) {
 200                 (void)mach_port_deallocate(mach_task_self(), *helper_port);
 201                 *helper_port = MACH_PORT_NULL;
 202         }
 203
 204         return FALSE;
 205
 206 }
 207
 208
 209 __private_extern__
 210 void
 211 _SCHelperClose(mach_port_t *helper_port)
 212 {
 213         if (!_SCHelperExec(*helper_port, SCHELPER_MSG_EXIT, NULL, NULL, NULL)) {
 214                 SC_log(LOG_INFO, "could not send exit request");
 215         }
 216
 217         if (*helper_port != MACH_PORT_NULL) {
 218                 (void)mach_port_deallocate(mach_task_self(), *helper_port);
 219                 *helper_port = MACH_PORT_NULL;
 220         }
 221
 222         return;
 223 }
 224
 225
 226 static CFDataRef
 227 _SCHelperExecCopyBacktrace()
 228 {
 229         static Boolean          loggingEnabled  = FALSE;
 230         static dispatch_once_t  once;
 231         CFDataRef               traceData       = NULL;
 232
 233         dispatch_once(&once, ^{
 234                 if(getenv("ENABLE_SCHELPER_BACKTRACES")) {
 235                         loggingEnabled = TRUE;
 236                 }
 237         });
 238
 239         if (loggingEnabled) {
 240                 CFStringRef     backtrace;
 241
 242                 backtrace = _SC_copyBacktrace();
 243                 if (backtrace != NULL) {
 244                         (void)_SCSerializeString(backtrace, &traceData, NULL, NULL);
 245                         CFRelease(backtrace);
 246                 }
 247         }
 248
 249         return traceData;
 250 }
 251
 252
 253 Boolean
 254 _SCHelperExec(mach_port_t port, uint32_t msgID, CFDataRef data, uint32_t *status, CFDataRef *reply)
 255 {
 256         kern_return_t           kr;
 257         CFDataRef               myData          = NULL;
 258         xmlDataOut_t            replyRef        = NULL;         /* raw bytes */
 259         mach_msg_type_number_t  replyLen        = 0;
 260         uint32_t                replyStatus     = 0;
 261         CFDataRef               traceData;
 262
 263         traceData = _SCHelperExecCopyBacktrace();
 264
 265         os_activity_scope(__SCHelperActivity());
 266
 267         kr = helperexec(port,
 268                         msgID,
 269                         (data != NULL) ? (void *)CFDataGetBytePtr(data) : NULL,
 270                         (data != NULL) ? (mach_msg_type_number_t)CFDataGetLength(data) : 0,
 271                         (traceData != NULL) ? (void *)CFDataGetBytePtr(traceData) : NULL,
 272                         (traceData != NULL) ? (mach_msg_type_number_t)CFDataGetLength(traceData) : 0,
 273                         &replyStatus,
 274                         &replyRef,
 275                         &replyLen);
 276
 277         if (traceData != NULL) {
 278                 CFRelease(traceData);
 279         }
 280
 281         if (kr != KERN_SUCCESS) {
 282                 if (replyRef != NULL) {
 283                         (void) vm_deallocate(mach_task_self(), (vm_address_t)replyRef, replyLen);
 284                 }
 285
 286                 if (kr != MACH_SEND_INVALID_DEST) {
 287                         // if we got an unexpected error
 288                         SC_log(LOG_NOTICE, "_SCHelperExec() failed: %s", mach_error_string(kr));
 289                 }
 290                 _SCErrorSet(kr);
 291
 292                 return FALSE;
 293         }
 294
 295         // un-serialize the reply
 296         if (replyRef != NULL) {
 297                 if (!_SCUnserializeData(&myData, replyRef, replyLen)) {
 298                         return FALSE;
 299                 }
 300         }
 301
 302         if (status != NULL) {
 303                 *status = replyStatus;
 304         }
 305
 306         if (reply != NULL) {
 307                 *reply = myData;
 308         } else if (myData != NULL) {
 309                 SC_log(LOG_INFO, "data available with no place to go");
 310                 CFRelease(myData);
 311         }
 312
 313         return TRUE;
 314 }