mDNSPosix/PosixDaemon.c

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved.
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   8  * as defined in and that are subject to the Apple Public Source License
   9  * Version 2.0 (the 'License'). You may not use this file except in
  10  * compliance with the License. Please obtain a copy of the License at
  11  * http://www.opensource.apple.com/apsl/ and read it before using this
  12  * file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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  19  * Please see the License for the specific language governing rights and
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  23
  24         File:           daemon.c
  25
  26         Contains:       main & associated Application layer for mDNSResponder on Linux.
  27
  28         Change History (most recent first):
  29
  30 $Log: PosixDaemon.c,v $
  31 Revision 1.29  2005/08/04 03:37:45  mkrochma
  32 Temporary workaround to fix posix after mDNS_SetPrimaryInterfaceInfo changed
  33
  34 Revision 1.28  2005/07/19 11:21:09  cheshire
  35 <rdar://problem/4170449> Unix Domain Socket leak in mdnsd
  36
  37 Revision 1.27  2005/02/04 00:39:59  cheshire
  38 Move ParseDNSServers() from PosixDaemon.c to mDNSPosix.c so all Posix client layers can use it
  39
  40 Revision 1.26  2005/02/02 02:21:30  cheshire
  41 Update references to "mDNSResponder" to say "mdnsd" instead
  42
  43 Revision 1.25  2005/01/27 20:01:50  cheshire
  44 udsSupportRemoveFDFromEventLoop() needs to close the file descriptor as well
  45
  46 Revision 1.24  2005/01/19 19:20:49  ksekar
  47 <rdar://problem/3960191> Need a way to turn off domain discovery
  48
  49 Revision 1.23  2004/12/16 20:17:11  cheshire
  50 <rdar://problem/3324626> Cache memory management improvements
  51
  52 Revision 1.22  2004/12/10 13:12:08  cheshire
  53 Create no-op function RecordUpdatedNiceLabel(), required by uds_daemon.c
  54
  55 Revision 1.21  2004/12/01 20:57:20  ksekar
  56 <rdar://problem/3873921> Wide Area Service Discovery must be split-DNS aware
  57
  58 Revision 1.20  2004/12/01 04:28:43  cheshire
  59 <rdar://problem/3872803> Darwin patches for Solaris and Suse
  60 Use version of daemon() provided in mDNSUNP.c instead of local copy
  61
  62 Revision 1.19  2004/12/01 03:30:29  cheshire
  63 <rdar://problem/3889346> Add Unicast DNS support to mDNSPosix
  64
  65 Revision 1.18  2004/11/30 22:45:59  cheshire
  66 Minor code tidying
  67
  68 Revision 1.17  2004/11/30 22:18:59  cheshire
  69 <rdar://problem/3889351> Posix needs to read the list of unicast DNS servers and set server list
  70
  71 Revision 1.16  2004/09/21 21:05:12      cheshire
  72 Move duplicate code out of mDNSMacOSX/daemon.c and mDNSPosix/PosixDaemon.c,
  73 into mDNSShared/uds_daemon.c
  74
  75 Revision 1.15  2004/09/17 01:08:53      cheshire
  76 Renamed mDNSClientAPI.h to mDNSEmbeddedAPI.h
  77   The name "mDNSClientAPI.h" is misleading to new developers looking at this code. The interfaces
  78   declared in that file are ONLY appropriate to single-address-space embedded applications.
  79   For clients on general-purpose computers, the interfaces defined in dns_sd.h should be used.
  80
  81 Revision 1.14  2004/09/16 00:24:49      cheshire
  82 <rdar://problem/3803162> Fix unsafe use of mDNSPlatformTimeNow()
  83
  84 Revision 1.13  2004/08/11 01:59:41      cheshire
  85 Remove "mDNS *globalInstance" parameter from udsserver_init()
  86
  87 Revision 1.12  2004/06/28 23:19:19      cheshire
  88 Fix "Daemon_Init declared but never defined" warning on Linux
  89
  90 Revision 1.11  2004/06/25 00:26:27      rpantos
  91 Changes to fix the Posix build on Solaris.
  92
  93 Revision 1.10  2004/06/08 04:59:40      cheshire
  94 Tidy up wording -- log messages are already prefixed with "mDNSResponder", so don't need to repeat it
  95
  96 Revision 1.9  2004/05/29 00:14:20  rpantos
  97 <rdar://problem/3508093> Runtime check to disable prod mdnsd on OS X.
  98
  99 Revision 1.8  2004/04/07 01:19:04  cheshire
 100 Hash slot value should be unsigned
 101
 102 Revision 1.7  2004/02/14 06:34:57  cheshire
 103 Use LogMsg instead of fprintf( stderr
 104
 105 Revision 1.6  2004/02/14 01:10:42  rpantos
 106 Allow daemon to run if 'nobody' is not defined, with a warning. (For Roku HD1000.)
 107
 108 Revision 1.5  2004/02/05 07:45:43  cheshire
 109 Add Log header
 110
 111 Revision 1.4  2004/01/28 21:14:23  cheshire
 112 Reconcile debug_mode and gDebugLogging into a single flag (mDNS_DebugMode)
 113
 114 Revision 1.3  2004/01/19 19:51:46  cheshire
 115 Fix compiler error (mixed declarations and code) on some versions of Linux
 116
 117 Revision 1.2  2003/12/11 03:03:51  rpantos
 118 Clean up mDNSPosix so that it builds on OS X again.
 119
 120 Revision 1.1  2003/12/08 20:47:02  rpantos
 121 Add support for mDNSResponder on Linux.
 122 */
 123
 124 #include <stdio.h>
 125 #include <string.h>
 126 #include <unistd.h>
 127 #include <stdlib.h>
 128 #include <signal.h>
 129 #include <errno.h>
 130 #include <fcntl.h>
 131 #include <pwd.h>
 132 #include <sys/types.h>
 133
 134 #include "mDNSEmbeddedAPI.h"
 135 #include "mDNSDebug.h"
 136 #include "mDNSPosix.h"
 137 #include "uds_daemon.h"
 138 #include "PlatformCommon.h"
 139
 140 #define CONFIG_FILE "/etc/mdnsd.conf"
 141 static domainname DynDNSZone;                // Default wide-area zone for service registration
 142 static domainname DynDNSHostname;
 143
 144 #define RR_CACHE_SIZE 500
 145 static CacheEntity gRRCache[RR_CACHE_SIZE];
 146
 147 extern const char mDNSResponderVersionString[];
 148
 149 static void Reconfigure(mDNS *m)
 150         {
 151         mDNSAddr DynDNSIP;
 152         mDNS_SetPrimaryInterfaceInfo(m, NULL, NULL, NULL);
 153         mDNS_DeleteDNSServers(m);
 154         if (ParseDNSServers(m, uDNS_SERVERS_FILE) < 0)
 155                 LogMsg("Unable to parse DNS server list. Unicast DNS-SD unavailable");
 156         ReadDDNSSettingsFromConfFile(m, CONFIG_FILE, &DynDNSHostname, &DynDNSZone, NULL);
 157         FindDefaultRouteIP(&DynDNSIP);
 158         if (DynDNSHostname.c[0]) mDNS_AddDynDNSHostName(m, &DynDNSHostname, NULL, NULL);
 159         if (DynDNSIP.type)       mDNS_SetPrimaryInterfaceInfo(m, &DynDNSIP, NULL, NULL);
 160         }
 161
 162 // Do appropriate things at startup with command line arguments. Calls exit() if unhappy.
 163 static void ParseCmdLinArgs(int argc, char **argv)
 164         {
 165         if (argc > 1)
 166                 {
 167                 if (0 == strcmp(argv[1], "-debug")) mDNS_DebugMode = mDNStrue;
 168                 else printf("Usage: %s [-debug]\n", argv[0]);
 169                 }
 170
 171         if (!mDNS_DebugMode)
 172                 {
 173                 int result = daemon(0, 0);
 174                 if (result != 0) { LogMsg("Could not run as daemon - exiting"); exit(result); }
 175 #if __APPLE__
 176                 LogMsg("The POSIX mdnsd should only be used on OS X for testing - exiting");
 177                 exit(-1);
 178 #endif
 179                 }
 180         }
 181
 182 static void             DumpStateLog(mDNS *const m)
 183 // Dump a little log of what we've been up to.
 184         {
 185         LogMsgIdent(mDNSResponderVersionString, "---- BEGIN STATE LOG ----");
 186         udsserver_info(m);
 187         LogMsgIdent(mDNSResponderVersionString, "----  END STATE LOG  ----");
 188         }
 189
 190 static mStatus  MainLoop(mDNS *m) // Loop until we quit.
 191         {
 192         sigset_t        signals;
 193         mDNSBool        gotData = mDNSfalse;
 194
 195         mDNSPosixListenForSignalInEventLoop(SIGINT);
 196         mDNSPosixListenForSignalInEventLoop(SIGTERM);
 197         mDNSPosixListenForSignalInEventLoop(SIGUSR1);
 198         mDNSPosixListenForSignalInEventLoop(SIGPIPE);
 199         mDNSPosixListenForSignalInEventLoop(SIGHUP) ;
 200
 201         for (; ;)
 202                 {
 203                 // Work out how long we expect to sleep before the next scheduled task
 204                 struct timeval  timeout;
 205                 mDNSs32                 ticks;
 206
 207                 // Only idle if we didn't find any data the last time around
 208                 if (!gotData)
 209                         {
 210                         mDNSs32                 nextTimerEvent = mDNS_Execute(m);
 211                         nextTimerEvent = udsserver_idle(nextTimerEvent);
 212                         ticks = nextTimerEvent - mDNS_TimeNow(m);
 213                         if (ticks < 1) ticks = 1;
 214                         }
 215                 else    // otherwise call EventLoop again with 0 timemout
 216                         ticks = 0;
 217
 218                 timeout.tv_sec = ticks / mDNSPlatformOneSecond;
 219                 timeout.tv_usec = (ticks % mDNSPlatformOneSecond) * 1000000 / mDNSPlatformOneSecond;
 220
 221                 (void) mDNSPosixRunEventLoopOnce(m, &timeout, &signals, &gotData);
 222
 223                 if (sigismember(&signals, SIGHUP )) Reconfigure(m);
 224                 if (sigismember(&signals, SIGUSR1)) DumpStateLog(m);
 225                 // SIGPIPE happens when we try to write to a dead client; death should be detected soon in request_callback() and cleaned up.
 226                 if (sigismember(&signals, SIGPIPE)) LogMsg("Received SIGPIPE - ignoring");
 227                 if (sigismember(&signals, SIGINT) || sigismember(&signals, SIGTERM)) break;
 228                 }
 229         return EINTR;
 230         }
 231
 232 int             main(int argc, char **argv)
 233         {
 234         #define mDNSRecord mDNSStorage
 235         mDNS_PlatformSupport    platformStorage;
 236         mStatus                                 err;
 237
 238         bzero(&mDNSRecord, sizeof mDNSRecord);
 239         bzero(&platformStorage, sizeof platformStorage);
 240
 241         ParseCmdLinArgs(argc, argv);
 242
 243         LogMsgIdent(mDNSResponderVersionString, "starting");
 244
 245         err = mDNS_Init(&mDNSRecord, &platformStorage, gRRCache, RR_CACHE_SIZE, mDNS_Init_AdvertiseLocalAddresses,
 246                                         mDNS_Init_NoInitCallback, mDNS_Init_NoInitCallbackContext);
 247
 248         if (mStatus_NoError == err)
 249                 err = udsserver_init();
 250
 251         Reconfigure(&mDNSRecord);
 252
 253         // Now that we're finished with anything privileged, switch over to running as "nobody"
 254         if (mStatus_NoError == err)
 255                 {
 256                 const struct passwd *pw = getpwnam("nobody");
 257                 if (pw != NULL)
 258                         setuid(pw->pw_uid);
 259                 else
 260                         LogMsg("WARNING: mdnsd continuing as root because user \"nobody\" does not exist");
 261                 }
 262
 263         if (mStatus_NoError == err)
 264                 err = MainLoop(&mDNSRecord);
 265
 266         LogMsgIdent(mDNSResponderVersionString, "stopping");
 267
 268         mDNS_Close(&mDNSRecord);
 269
 270         if (udsserver_exit() < 0)
 271                 LogMsg("ExitCallback: udsserver_exit failed");
 272
 273  #if MDNS_DEBUGMSGS > 0
 274         printf("mDNSResponder exiting normally with %ld\n", err);
 275  #endif
 276
 277         return err;
 278         }
 279
 280 //              uds_daemon support              ////////////////////////////////////////////////////////////
 281
 282 #if MDNS_MALLOC_DEBUGGING >= 2
 283 #define LogMalloc LogMsg
 284 #else
 285 #define LogMalloc(ARGS...) ((void)0)
 286 #endif
 287
 288 mStatus udsSupportAddFDToEventLoop(int fd, udsEventCallback callback, void *context)
 289 /* Support routine for uds_daemon.c */
 290         {
 291         // Depends on the fact that udsEventCallback == mDNSPosixEventCallback
 292         return mDNSPosixAddFDToEventLoop(fd, callback, context);
 293         }
 294
 295 mStatus udsSupportRemoveFDFromEventLoop(int fd)         // Note: This also CLOSES the file descriptor
 296         {
 297         mStatus err = mDNSPosixRemoveFDFromEventLoop(fd);
 298         close(fd);
 299         return err;
 300         }
 301
 302 mDNSexport void RecordUpdatedNiceLabel(mDNS *const m, mDNSs32 delay)
 303         {
 304         (void)m;
 305         (void)delay;
 306         // No-op, for now
 307         }
 308
 309 #if MACOSX_MDNS_MALLOC_DEBUGGING >= 1
 310
 311 void *mallocL(char *msg, unsigned int size)
 312         {
 313         unsigned long *mem = malloc(size+8);
 314         if (!mem)
 315                 {
 316                 LogMsg("malloc( %s : %d ) failed", msg, size);
 317                 return(NULL);
 318                 }
 319         else
 320                 {
 321                 LogMalloc("malloc( %s : %lu ) = %p", msg, size, &mem[2]);
 322                 mem[0] = 0xDEAD1234;
 323                 mem[1] = size;
 324                 //bzero(&mem[2], size);
 325                 memset(&mem[2], 0xFF, size);
 326 //              validatelists(&mDNSStorage);
 327                 return(&mem[2]);
 328                 }
 329         }
 330
 331 void freeL(char *msg, void *x)
 332         {
 333         if (!x)
 334                 LogMsg("free( %s @ NULL )!", msg);
 335         else
 336                 {
 337                 unsigned long *mem = ((unsigned long *)x) - 2;
 338                 if (mem[0] != 0xDEAD1234)
 339                         { LogMsg("free( %s @ %p ) !!!! NOT ALLOCATED !!!!", msg, &mem[2]); return; }
 340                 if (mem[1] > 8000)
 341                         { LogMsg("free( %s : %ld @ %p) too big!", msg, mem[1], &mem[2]); return; }
 342                 LogMalloc("free( %s : %ld @ %p)", msg, mem[1], &mem[2]);
 343                 //bzero(mem, mem[1]+8);
 344                 memset(mem, 0xDD, mem[1]+8);
 345 //              validatelists(&mDNSStorage);
 346                 free(mem);
 347                 }
 348         }
 349
 350 #endif // MACOSX_MDNS_MALLOC_DEBUGGING >= 1
 351
 352 // For convenience when using the "strings" command, this is the last thing in the file
 353 #if mDNSResponderVersion > 1
 354 mDNSexport const char mDNSResponderVersionString[] = "mDNSResponder-" STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ") ";
 355 #else
 356 mDNSexport const char mDNSResponderVersionString[] = "mDNSResponder (Engineering Build) (" __DATE__ " " __TIME__ ") ";
 357 #endif