mDNSPosix/PosixDaemon.c

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16
  17         File:           daemon.c
  18
  19         Contains:       main & associated Application layer for mDNSResponder on Linux.
  20
  21         Change History (most recent first):
  22
  23 $Log: PosixDaemon.c,v $
  24 Revision 1.49  2009/04/30 20:07:51  mcguire
  25 <rdar://problem/6822674> Support multiple UDSs from launchd
  26
  27 Revision 1.48  2009/04/11 01:43:28  jessic2
  28 <rdar://problem/4426780> Daemon: Should be able to turn on LogOperation dynamically
  29
  30 Revision 1.47  2009/01/11 03:20:06  mkrochma
  31 <rdar://problem/5797526> Fixes from Igor Seleznev to get mdnsd working on Solaris
  32
  33 Revision 1.46  2008/11/03 23:09:15  cheshire
  34 Don't need to include mDNSDebug.h as well as mDNSEmbeddedAPI.h
  35
  36 Revision 1.45  2008/10/03 18:25:17  cheshire
  37 Instead of calling "m->MainCallback" function pointer directly, call mDNSCore routine "mDNS_ConfigChanged(m);"
  38
  39 Revision 1.44  2008/09/15 23:52:30  cheshire
  40 <rdar://problem/6218902> mDNSResponder-177 fails to compile on Linux with .desc pseudo-op
  41 Made __crashreporter_info__ symbol conditional, so we only use it for OS X build
  42
  43 Revision 1.43  2007/10/22 20:05:34  cheshire
  44 Use mDNSPlatformSourceAddrForDest instead of FindSourceAddrForIP
  45
  46 Revision 1.42  2007/09/18 19:09:02  cheshire
  47 <rdar://problem/5489549> mDNSResponderHelper (and other binaries) missing SCCS version strings
  48
  49 Revision 1.41  2007/09/04 17:02:25  cheshire
  50 <rdar://problem/5458929> False positives in changed files list in nightly builds
  51 Added MDNS_VERSIONSTR_NODTS option at the reqest of Rishi Srivatsavai (Sun)
  52
  53 Revision 1.40  2007/07/31 23:08:34  mcguire
  54 <rdar://problem/5329542> BTMM: Make AutoTunnel mode work with multihoming
  55
  56 Revision 1.39  2007/03/21 00:30:44  cheshire
  57 Remove obsolete mDNS_DeleteDNSServers() call
  58
  59 Revision 1.38  2007/02/14 01:58:19  cheshire
  60 <rdar://problem/4995831> Don't delete Unix Domain Socket on exit if we didn't create it on startup
  61
  62 Revision 1.37  2007/02/07 19:32:00  cheshire
  63 <rdar://problem/4980353> All mDNSResponder components should contain version strings in SCCS-compatible format
  64
  65 Revision 1.36  2007/02/06 19:06:48  cheshire
  66 <rdar://problem/3956518> Need to go native with launchd
  67
  68 Revision 1.35  2007/01/05 08:30:52  cheshire
  69 Trim excessive "$Log" checkin history from before 2006
  70 (checkin history still available via "cvs log ..." of course)
  71
  72 Revision 1.34  2007/01/05 05:46:08  cheshire
  73 Add mDNS *const m parameter to udsserver_handle_configchange()
  74
  75 Revision 1.33  2006/12/21 00:10:53  cheshire
  76 Make mDNS_PlatformSupport PlatformStorage a static global instead of a stack variable
  77
  78 Revision 1.32  2006/11/03 22:28:50  cheshire
  79 PosixDaemon needs to handle mStatus_ConfigChanged and mStatus_GrowCache messages
  80
  81 Revision 1.31  2006/08/14 23:24:46  cheshire
  82 Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0
  83
  84 Revision 1.30  2006/07/07 01:09:12  cheshire
  85 <rdar://problem/4472013> Add Private DNS server functionality to dnsextd
  86 Only use mallocL/freeL debugging routines when building mDNSResponder, not dnsextd
  87
  88 */
  89
  90 #include <stdio.h>
  91 #include <string.h>
  92 #include <unistd.h>
  93 #include <stdlib.h>
  94 #include <signal.h>
  95 #include <errno.h>
  96 #include <fcntl.h>
  97 #include <pwd.h>
  98 #include <sys/types.h>
  99
 100 #include "mDNSEmbeddedAPI.h"
 101 #include "mDNSPosix.h"
 102 #include "mDNSUNP.h"            // For daemon()
 103 #include "uds_daemon.h"
 104 #include "PlatformCommon.h"
 105
 106 #define CONFIG_FILE "/etc/mdnsd.conf"
 107 static domainname DynDNSZone;                // Default wide-area zone for service registration
 108 static domainname DynDNSHostname;
 109
 110 #define RR_CACHE_SIZE 500
 111 static CacheEntity gRRCache[RR_CACHE_SIZE];
 112 static mDNS_PlatformSupport PlatformStorage;
 113
 114 mDNSlocal void mDNS_StatusCallback(mDNS *const m, mStatus result)
 115         {
 116         (void)m; // Unused
 117         if (result == mStatus_NoError)
 118                 {
 119                 // On successful registration of dot-local mDNS host name, daemon may want to check if
 120                 // any name conflict and automatic renaming took place, and if so, record the newly negotiated
 121                 // name in persistent storage for next time. It should also inform the user of the name change.
 122                 // On Mac OS X we store the current dot-local mDNS host name in the SCPreferences store,
 123                 // and notify the user with a CFUserNotification.
 124                 }
 125         else if (result == mStatus_ConfigChanged)
 126                 {
 127                 udsserver_handle_configchange(m);
 128                 }
 129         else if (result == mStatus_GrowCache)
 130                 {
 131                 // Allocate another chunk of cache storage
 132                 CacheEntity *storage = malloc(sizeof(CacheEntity) * RR_CACHE_SIZE);
 133                 if (storage) mDNS_GrowCache(m, storage, RR_CACHE_SIZE);
 134                 }
 135         }
 136
 137 // %%% Reconfigure() probably belongs in the platform support layer (mDNSPosix.c), not the daemon cde
 138 // -- all client layers running on top of mDNSPosix.c need to handle network configuration changes,
 139 // not only the Unix Domain Socket Daemon
 140
 141 static void Reconfigure(mDNS *m)
 142         {
 143         mDNSAddr DynDNSIP;
 144         const mDNSAddr dummy = { mDNSAddrType_IPv4, { { { 1, 1, 1, 1 } } } };;
 145         mDNS_SetPrimaryInterfaceInfo(m, NULL, NULL, NULL);
 146         if (ParseDNSServers(m, uDNS_SERVERS_FILE) < 0)
 147                 LogMsg("Unable to parse DNS server list. Unicast DNS-SD unavailable");
 148         ReadDDNSSettingsFromConfFile(m, CONFIG_FILE, &DynDNSHostname, &DynDNSZone, NULL);
 149         mDNSPlatformSourceAddrForDest(&DynDNSIP, &dummy);
 150         if (DynDNSHostname.c[0]) mDNS_AddDynDNSHostName(m, &DynDNSHostname, NULL, NULL);
 151         if (DynDNSIP.type)       mDNS_SetPrimaryInterfaceInfo(m, &DynDNSIP, NULL, NULL);
 152         mDNS_ConfigChanged(m);
 153         }
 154
 155 // Do appropriate things at startup with command line arguments. Calls exit() if unhappy.
 156 mDNSlocal void ParseCmdLinArgs(int argc, char **argv)
 157         {
 158         if (argc > 1)
 159                 {
 160                 if (0 == strcmp(argv[1], "-debug")) mDNS_DebugMode = mDNStrue;
 161                 else printf("Usage: %s [-debug]\n", argv[0]);
 162                 }
 163
 164         if (!mDNS_DebugMode)
 165                 {
 166                 int result = daemon(0, 0);
 167                 if (result != 0) { LogMsg("Could not run as daemon - exiting"); exit(result); }
 168 #if __APPLE__
 169                 LogMsg("The POSIX mdnsd should only be used on OS X for testing - exiting");
 170                 exit(-1);
 171 #endif
 172                 }
 173         }
 174
 175 mDNSlocal void DumpStateLog(mDNS *const m)
 176 // Dump a little log of what we've been up to.
 177         {
 178         LogMsg("---- BEGIN STATE LOG ----");
 179         udsserver_info(m);
 180         LogMsg("----  END STATE LOG  ----");
 181         }
 182
 183 mDNSlocal mStatus MainLoop(mDNS *m) // Loop until we quit.
 184         {
 185         sigset_t        signals;
 186         mDNSBool        gotData = mDNSfalse;
 187
 188         mDNSPosixListenForSignalInEventLoop(SIGINT);
 189         mDNSPosixListenForSignalInEventLoop(SIGTERM);
 190         mDNSPosixListenForSignalInEventLoop(SIGUSR1);
 191         mDNSPosixListenForSignalInEventLoop(SIGPIPE);
 192         mDNSPosixListenForSignalInEventLoop(SIGHUP) ;
 193
 194         for (; ;)
 195                 {
 196                 // Work out how long we expect to sleep before the next scheduled task
 197                 struct timeval  timeout;
 198                 mDNSs32                 ticks;
 199
 200                 // Only idle if we didn't find any data the last time around
 201                 if (!gotData)
 202                         {
 203                         mDNSs32                 nextTimerEvent = mDNS_Execute(m);
 204                         nextTimerEvent = udsserver_idle(nextTimerEvent);
 205                         ticks = nextTimerEvent - mDNS_TimeNow(m);
 206                         if (ticks < 1) ticks = 1;
 207                         }
 208                 else    // otherwise call EventLoop again with 0 timemout
 209                         ticks = 0;
 210
 211                 timeout.tv_sec = ticks / mDNSPlatformOneSecond;
 212                 timeout.tv_usec = (ticks % mDNSPlatformOneSecond) * 1000000 / mDNSPlatformOneSecond;
 213
 214                 (void) mDNSPosixRunEventLoopOnce(m, &timeout, &signals, &gotData);
 215
 216                 if (sigismember(&signals, SIGHUP )) Reconfigure(m);
 217                 if (sigismember(&signals, SIGUSR1)) DumpStateLog(m);
 218                 // SIGPIPE happens when we try to write to a dead client; death should be detected soon in request_callback() and cleaned up.
 219                 if (sigismember(&signals, SIGPIPE)) LogMsg("Received SIGPIPE - ignoring");
 220                 if (sigismember(&signals, SIGINT) || sigismember(&signals, SIGTERM)) break;
 221                 }
 222         return EINTR;
 223         }
 224
 225 int main(int argc, char **argv)
 226         {
 227         mStatus                                 err;
 228
 229         ParseCmdLinArgs(argc, argv);
 230
 231         LogMsg("%s starting", mDNSResponderVersionString);
 232
 233         err = mDNS_Init(&mDNSStorage, &PlatformStorage, gRRCache, RR_CACHE_SIZE, mDNS_Init_AdvertiseLocalAddresses,
 234                                         mDNS_StatusCallback, mDNS_Init_NoInitCallbackContext);
 235
 236         if (mStatus_NoError == err)
 237                 err = udsserver_init(mDNSNULL, 0);
 238
 239         Reconfigure(&mDNSStorage);
 240
 241         // Now that we're finished with anything privileged, switch over to running as "nobody"
 242         if (mStatus_NoError == err)
 243                 {
 244                 const struct passwd *pw = getpwnam("nobody");
 245                 if (pw != NULL)
 246                         setuid(pw->pw_uid);
 247                 else
 248                         LogMsg("WARNING: mdnsd continuing as root because user \"nobody\" does not exist");
 249                 }
 250
 251         if (mStatus_NoError == err)
 252                 err = MainLoop(&mDNSStorage);
 253
 254         LogMsg("%s stopping", mDNSResponderVersionString);
 255
 256         mDNS_Close(&mDNSStorage);
 257
 258         if (udsserver_exit() < 0)
 259                 LogMsg("ExitCallback: udsserver_exit failed");
 260
 261  #if MDNS_DEBUGMSGS > 0
 262         printf("mDNSResponder exiting normally with %ld\n", err);
 263  #endif
 264
 265         return err;
 266         }
 267
 268 //              uds_daemon support              ////////////////////////////////////////////////////////////
 269
 270 mStatus udsSupportAddFDToEventLoop(int fd, udsEventCallback callback, void *context)
 271 /* Support routine for uds_daemon.c */
 272         {
 273         // Depends on the fact that udsEventCallback == mDNSPosixEventCallback
 274         return mDNSPosixAddFDToEventLoop(fd, callback, context);
 275         }
 276
 277 mStatus udsSupportRemoveFDFromEventLoop(int fd)         // Note: This also CLOSES the file descriptor
 278         {
 279         mStatus err = mDNSPosixRemoveFDFromEventLoop(fd);
 280         close(fd);
 281         return err;
 282         }
 283
 284 mDNSexport void RecordUpdatedNiceLabel(mDNS *const m, mDNSs32 delay)
 285         {
 286         (void)m;
 287         (void)delay;
 288         // No-op, for now
 289         }
 290
 291 #if _BUILDING_XCODE_PROJECT_
 292 // If the process crashes, then this string will be magically included in the automatically-generated crash log
 293 const char *__crashreporter_info__ = mDNSResponderVersionString_SCCS + 5;
 294 asm(".desc ___crashreporter_info__, 0x10");
 295 #endif
 296
 297 // For convenience when using the "strings" command, this is the last thing in the file
 298 #if mDNSResponderVersion > 1
 299 mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder-" STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ")";
 300 #elif MDNS_VERSIONSTR_NODTS
 301 mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder (Engineering Build)";
 302 #else
 303 mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder (Engineering Build) (" __DATE__ " " __TIME__ ")";
 304 #endif