SystemConfiguration.fproj/helper/SCHelper_client.c

   1 /*
   2  * Copyright (c) 2005-2008, 2010, 2011, 2013, 2015, 2016, 2018, 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 #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 mach_port_t
  59 __SCHelperServerPort(kern_return_t *status)
  60 {
  61         mach_port_t     server  = MACH_PORT_NULL;
  62         char            *server_name;
  63
  64         server_name = getenv("SCHELPER_SERVER");
  65         if (!server_name) {
  66                 server_name = SCHELPER_SERVER;
  67         }
  68
  69 #ifdef  BOOTSTRAP_PRIVILEGED_SERVER
  70         *status = bootstrap_look_up2(bootstrap_port,
  71                                      server_name,
  72                                      &server,
  73                                      0,
  74                                      BOOTSTRAP_PRIVILEGED_SERVER);
  75 #else   // BOOTSTRAP_PRIVILEGED_SERVER
  76         *status = bootstrap_look_up(bootstrap_port, server_name, &server);
  77 #endif  // BOOTSTRAP_PRIVILEGED_SERVER
  78
  79         switch (*status) {
  80                 case BOOTSTRAP_SUCCESS :
  81                         /* service currently registered, "a good thing" (tm) */
  82                         return server;
  83                 case BOOTSTRAP_NOT_PRIVILEGED :
  84                         /* the service is not privileged */
  85                         break;
  86                 case BOOTSTRAP_UNKNOWN_SERVICE :
  87                         /* service not currently registered, try again later */
  88                         break;
  89                 default :
  90 #ifdef  DEBUG
  91                         SC_log(LOG_INFO, "bootstrap_look_up() failed: status=%s",
  92                                bootstrap_strerror(*status));
  93 #endif  /* DEBUG */
  94                         break;
  95         }
  96
  97         return MACH_PORT_NULL;
  98 }
  99
 100
 101 __private_extern__
 102 Boolean
 103 _SCHelperOpen(CFDataRef authorizationData, mach_port_t *helper_port)
 104 {
 105         kern_return_t           kr;
 106         Boolean                 ok;
 107         mach_port_t             server;
 108         uint32_t                status  = 0;
 109
 110         *helper_port = MACH_PORT_NULL;
 111
 112         // open a new session with the server
 113         server = _helper_server;
 114         while (TRUE) {
 115                 if (server != MACH_PORT_NULL) {
 116                         kr = helperinit(server,
 117                                         helper_port,
 118                                         &status);
 119                         if (kr == KERN_SUCCESS) {
 120                                 break;
 121                         }
 122
 123                         // our [cached] server port is not valid
 124                         if (kr != MACH_SEND_INVALID_DEST) {
 125                                 // if we got an unexpected error, don't retry
 126                                 status = kr;
 127                                 break;
 128                         }
 129                 }
 130
 131                 pthread_mutex_lock(&_helper_lock);
 132                 if (_helper_server != MACH_PORT_NULL) {
 133                         if (server == _helper_server) {
 134                                 // if the server we tried returned the error
 135                                 (void)mach_port_deallocate(mach_task_self(), _helper_server);
 136                                 _helper_server = __SCHelperServerPort(&kr);
 137                                 if (_helper_server == MACH_PORT_NULL) {
 138                                         status = kr;
 139                                 }
 140                         } else {
 141                                 // another thread has refreshed the SCHelper server port
 142                         }
 143                 } else {
 144                         _helper_server = __SCHelperServerPort(&kr);
 145                         if (_helper_server == MACH_PORT_NULL) {
 146                                 status = kr;
 147                         }
 148                 }
 149                 server = _helper_server;
 150                 pthread_mutex_unlock(&_helper_lock);
 151
 152                 if (server == MACH_PORT_NULL) {
 153                         // if SCHelper server not available
 154                         break;
 155                 }
 156         }
 157         __MACH_PORT_DEBUG(TRUE, "*** _SCHelperOpen", *helper_port);
 158
 159         if (*helper_port == MACH_PORT_NULL) {
 160                 SC_log(LOG_NOTICE, "could not contact \"" HELPER "\": %s",
 161                       SCErrorString(status));
 162                 return FALSE;
 163         }
 164
 165         ok = _SCHelperExec(*helper_port, SCHELPER_MSG_AUTH, authorizationData, &status, NULL);
 166         if (!ok) {
 167                 SC_log(LOG_NOTICE, "could not send authorization");
 168                 goto error;
 169         }
 170
 171         ok = (status == 0);
 172         if (!ok) {
 173                 SC_log(LOG_NOTICE, "could not start \"" HELPER "\", status = %u", status);
 174                 goto error;
 175         }
 176
 177         return TRUE;
 178
 179     error :
 180
 181         if (*helper_port != MACH_PORT_NULL) {
 182                 (void)mach_port_deallocate(mach_task_self(), *helper_port);
 183                 *helper_port = MACH_PORT_NULL;
 184         }
 185
 186         return FALSE;
 187
 188 }
 189
 190
 191 __private_extern__
 192 void
 193 _SCHelperClose(mach_port_t *helper_port)
 194 {
 195         if (!_SCHelperExec(*helper_port, SCHELPER_MSG_EXIT, NULL, NULL, NULL)) {
 196                 SC_log(LOG_INFO, "could not send exit request");
 197         }
 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;
 205 }
 206
 207
 208 static CFDataRef
 209 _SCHelperExecCopyBacktrace()
 210 {
 211         static Boolean          loggingEnabled  = FALSE;
 212         static dispatch_once_t  once;
 213         CFDataRef               traceData       = NULL;
 214
 215         dispatch_once(&once, ^{
 216                 if(getenv("ENABLE_SCHELPER_BACKTRACES")) {
 217                         loggingEnabled = TRUE;
 218                 }
 219         });
 220
 221         if (loggingEnabled) {
 222                 CFStringRef     backtrace;
 223
 224                 backtrace = _SC_copyBacktrace();
 225                 if (backtrace != NULL) {
 226                         (void)_SCSerializeString(backtrace, &traceData, NULL, NULL);
 227                         CFRelease(backtrace);
 228                 }
 229         }
 230
 231         return traceData;
 232 }
 233
 234
 235 __private_extern__
 236 Boolean
 237 _SCHelperExec(mach_port_t port, uint32_t msgID, CFDataRef data, uint32_t *status, CFDataRef *reply)
 238 {
 239         kern_return_t           kr;
 240         CFDataRef               myData          = NULL;
 241         xmlDataOut_t            replyRef        = NULL;         /* raw bytes */
 242         mach_msg_type_number_t  replyLen        = 0;
 243         uint32_t                replyStatus     = 0;
 244         CFDataRef               traceData;
 245
 246         traceData = _SCHelperExecCopyBacktrace();
 247
 248         kr = helperexec(port,
 249                         msgID,
 250                         (data != NULL) ? (void *)CFDataGetBytePtr(data) : NULL,
 251                         (data != NULL) ? (mach_msg_type_number_t)CFDataGetLength(data) : 0,
 252                         (traceData != NULL) ? (void *)CFDataGetBytePtr(traceData) : NULL,
 253                         (traceData != NULL) ? (mach_msg_type_number_t)CFDataGetLength(traceData) : 0,
 254                         &replyStatus,
 255                         &replyRef,
 256                         &replyLen);
 257
 258         if (traceData != NULL) {
 259                 CFRelease(traceData);
 260         }
 261
 262         if (kr != KERN_SUCCESS) {
 263                 if (replyRef != NULL) {
 264                         (void) vm_deallocate(mach_task_self(), (vm_address_t)replyRef, replyLen);
 265                 }
 266
 267                 if (kr != MACH_SEND_INVALID_DEST) {
 268                         // if we got an unexpected error
 269                         SC_log(LOG_NOTICE, "_SCHelperExec() failed: %s", mach_error_string(kr));
 270                 }
 271                 _SCErrorSet(kr);
 272
 273                 return FALSE;
 274         }
 275
 276         // un-serialize the reply
 277         if (replyRef != NULL) {
 278                 if (!_SCUnserializeData(&myData, replyRef, replyLen)) {
 279                         return FALSE;
 280                 }
 281         }
 282
 283         if (status != NULL) {
 284                 *status = replyStatus;
 285         }
 286
 287         if (reply != NULL) {
 288                 *reply = myData;
 289         } else if (myData != NULL) {
 290                 SC_log(LOG_INFO, "data available with no place to go");
 291                 CFRelease(myData);
 292         }
 293
 294         return TRUE;
 295 }