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