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 1.29.2.1  2006/08/29 06:24:34  cheshire
  25 Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0
  26
  27 Revision 1.29  2005/08/04 03:37:45  mkrochma
  28 Temporary workaround to fix posix after mDNS_SetPrimaryInterfaceInfo changed
  29
  30 Revision 1.28  2005/07/19 11:21:09  cheshire
  31 <rdar://problem/4170449> Unix Domain Socket leak in mdnsd
  32
  33 Revision 1.27  2005/02/04 00:39:59  cheshire
  34 Move ParseDNSServers() from PosixDaemon.c to mDNSPosix.c so all Posix client layers can use it
  35
  36 Revision 1.26  2005/02/02 02:21:30  cheshire
  37 Update references to "mDNSResponder" to say "mdnsd" instead
  38
  39 Revision 1.25  2005/01/27 20:01:50  cheshire
  40 udsSupportRemoveFDFromEventLoop() needs to close the file descriptor as well
  41
  42 Revision 1.24  2005/01/19 19:20:49  ksekar
  43 <rdar://problem/3960191> Need a way to turn off domain discovery
  44
  45 Revision 1.23  2004/12/16 20:17:11  cheshire
  46 <rdar://problem/3324626> Cache memory management improvements
  47
  48 Revision 1.22  2004/12/10 13:12:08  cheshire
  49 Create no-op function RecordUpdatedNiceLabel(), required by uds_daemon.c
  50
  51 Revision 1.21  2004/12/01 20:57:20  ksekar
  52 <rdar://problem/3873921> Wide Area Service Discovery must be split-DNS aware
  53
  54 Revision 1.20  2004/12/01 04:28:43  cheshire
  55 <rdar://problem/3872803> Darwin patches for Solaris and Suse
  56 Use version of daemon() provided in mDNSUNP.c instead of local copy
  57
  58 Revision 1.19  2004/12/01 03:30:29  cheshire
  59 <rdar://problem/3889346> Add Unicast DNS support to mDNSPosix
  60
  61 Revision 1.18  2004/11/30 22:45:59  cheshire
  62 Minor code tidying
  63
  64 Revision 1.17  2004/11/30 22:18:59  cheshire
  65 <rdar://problem/3889351> Posix needs to read the list of unicast DNS servers and set server list
  66
  67 Revision 1.16  2004/09/21 21:05:12      cheshire
  68 Move duplicate code out of mDNSMacOSX/daemon.c and mDNSPosix/PosixDaemon.c,
  69 into mDNSShared/uds_daemon.c
  70
  71 Revision 1.15  2004/09/17 01:08:53      cheshire
  72 Renamed mDNSClientAPI.h to mDNSEmbeddedAPI.h
  73   The name "mDNSClientAPI.h" is misleading to new developers looking at this code. The interfaces
  74   declared in that file are ONLY appropriate to single-address-space embedded applications.
  75   For clients on general-purpose computers, the interfaces defined in dns_sd.h should be used.
  76
  77 Revision 1.14  2004/09/16 00:24:49      cheshire
  78 <rdar://problem/3803162> Fix unsafe use of mDNSPlatformTimeNow()
  79
  80 Revision 1.13  2004/08/11 01:59:41      cheshire
  81 Remove "mDNS *globalInstance" parameter from udsserver_init()
  82
  83 Revision 1.12  2004/06/28 23:19:19      cheshire
  84 Fix "Daemon_Init declared but never defined" warning on Linux
  85
  86 Revision 1.11  2004/06/25 00:26:27      rpantos
  87 Changes to fix the Posix build on Solaris.
  88
  89 Revision 1.10  2004/06/08 04:59:40      cheshire
  90 Tidy up wording -- log messages are already prefixed with "mDNSResponder", so don't need to repeat it
  91
  92 Revision 1.9  2004/05/29 00:14:20  rpantos
  93 <rdar://problem/3508093> Runtime check to disable prod mdnsd on OS X.
  94
  95 Revision 1.8  2004/04/07 01:19:04  cheshire
  96 Hash slot value should be unsigned
  97
  98 Revision 1.7  2004/02/14 06:34:57  cheshire
  99 Use LogMsg instead of fprintf( stderr
 100
 101 Revision 1.6  2004/02/14 01:10:42  rpantos
 102 Allow daemon to run if 'nobody' is not defined, with a warning. (For Roku HD1000.)
 103
 104 Revision 1.5  2004/02/05 07:45:43  cheshire
 105 Add Log header
 106
 107 Revision 1.4  2004/01/28 21:14:23  cheshire
 108 Reconcile debug_mode and gDebugLogging into a single flag (mDNS_DebugMode)
 109
 110 Revision 1.3  2004/01/19 19:51:46  cheshire
 111 Fix compiler error (mixed declarations and code) on some versions of Linux
 112
 113 Revision 1.2  2003/12/11 03:03:51  rpantos
 114 Clean up mDNSPosix so that it builds on OS X again.
 115
 116 Revision 1.1  2003/12/08 20:47:02  rpantos
 117 Add support for mDNSResponder on Linux.
 118 */
 119
 120 #include <stdio.h>
 121 #include <string.h>
 122 #include <unistd.h>
 123 #include <stdlib.h>
 124 #include <signal.h>
 125 #include <errno.h>
 126 #include <fcntl.h>
 127 #include <pwd.h>
 128 #include <sys/types.h>
 129
 130 #include "mDNSEmbeddedAPI.h"
 131 #include "mDNSDebug.h"
 132 #include "mDNSPosix.h"
 133 #include "uds_daemon.h"
 134 #include "PlatformCommon.h"
 135
 136 #define CONFIG_FILE "/etc/mdnsd.conf"
 137 static domainname DynDNSZone;                // Default wide-area zone for service registration
 138 static domainname DynDNSHostname;
 139
 140 #define RR_CACHE_SIZE 500
 141 static CacheEntity gRRCache[RR_CACHE_SIZE];
 142
 143 extern const char mDNSResponderVersionString[];
 144
 145 static void Reconfigure(mDNS *m)
 146         {
 147         mDNSAddr DynDNSIP;
 148         mDNS_SetPrimaryInterfaceInfo(m, NULL, NULL, NULL);
 149         mDNS_DeleteDNSServers(m);
 150         if (ParseDNSServers(m, uDNS_SERVERS_FILE) < 0)
 151                 LogMsg("Unable to parse DNS server list. Unicast DNS-SD unavailable");
 152         ReadDDNSSettingsFromConfFile(m, CONFIG_FILE, &DynDNSHostname, &DynDNSZone, NULL);
 153         FindDefaultRouteIP(&DynDNSIP);
 154         if (DynDNSHostname.c[0]) mDNS_AddDynDNSHostName(m, &DynDNSHostname, NULL, NULL);
 155         if (DynDNSIP.type)       mDNS_SetPrimaryInterfaceInfo(m, &DynDNSIP, NULL, NULL);
 156         }
 157
 158 // Do appropriate things at startup with command line arguments. Calls exit() if unhappy.
 159 static void ParseCmdLinArgs(int argc, char **argv)
 160         {
 161         if (argc > 1)
 162                 {
 163                 if (0 == strcmp(argv[1], "-debug")) mDNS_DebugMode = mDNStrue;
 164                 else printf("Usage: %s [-debug]\n", argv[0]);
 165                 }
 166
 167         if (!mDNS_DebugMode)
 168                 {
 169                 int result = daemon(0, 0);
 170                 if (result != 0) { LogMsg("Could not run as daemon - exiting"); exit(result); }
 171 #if __APPLE__
 172                 LogMsg("The POSIX mdnsd should only be used on OS X for testing - exiting");
 173                 exit(-1);
 174 #endif
 175                 }
 176         }
 177
 178 static void             DumpStateLog(mDNS *const m)
 179 // Dump a little log of what we've been up to.
 180         {
 181         LogMsgIdent(mDNSResponderVersionString, "---- BEGIN STATE LOG ----");
 182         udsserver_info(m);
 183         LogMsgIdent(mDNSResponderVersionString, "----  END STATE LOG  ----");
 184         }
 185
 186 static mStatus  MainLoop(mDNS *m) // Loop until we quit.
 187         {
 188         sigset_t        signals;
 189         mDNSBool        gotData = mDNSfalse;
 190
 191         mDNSPosixListenForSignalInEventLoop(SIGINT);
 192         mDNSPosixListenForSignalInEventLoop(SIGTERM);
 193         mDNSPosixListenForSignalInEventLoop(SIGUSR1);
 194         mDNSPosixListenForSignalInEventLoop(SIGPIPE);
 195         mDNSPosixListenForSignalInEventLoop(SIGHUP) ;
 196
 197         for (; ;)
 198                 {
 199                 // Work out how long we expect to sleep before the next scheduled task
 200                 struct timeval  timeout;
 201                 mDNSs32                 ticks;
 202
 203                 // Only idle if we didn't find any data the last time around
 204                 if (!gotData)
 205                         {
 206                         mDNSs32                 nextTimerEvent = mDNS_Execute(m);
 207                         nextTimerEvent = udsserver_idle(nextTimerEvent);
 208                         ticks = nextTimerEvent - mDNS_TimeNow(m);
 209                         if (ticks < 1) ticks = 1;
 210                         }
 211                 else    // otherwise call EventLoop again with 0 timemout
 212                         ticks = 0;
 213
 214                 timeout.tv_sec = ticks / mDNSPlatformOneSecond;
 215                 timeout.tv_usec = (ticks % mDNSPlatformOneSecond) * 1000000 / mDNSPlatformOneSecond;
 216
 217                 (void) mDNSPosixRunEventLoopOnce(m, &timeout, &signals, &gotData);
 218
 219                 if (sigismember(&signals, SIGHUP )) Reconfigure(m);
 220                 if (sigismember(&signals, SIGUSR1)) DumpStateLog(m);
 221                 // SIGPIPE happens when we try to write to a dead client; death should be detected soon in request_callback() and cleaned up.
 222                 if (sigismember(&signals, SIGPIPE)) LogMsg("Received SIGPIPE - ignoring");
 223                 if (sigismember(&signals, SIGINT) || sigismember(&signals, SIGTERM)) break;
 224                 }
 225         return EINTR;
 226         }
 227
 228 int             main(int argc, char **argv)
 229         {
 230         #define mDNSRecord mDNSStorage
 231         mDNS_PlatformSupport    platformStorage;
 232         mStatus                                 err;
 233
 234         bzero(&mDNSRecord, sizeof mDNSRecord);
 235         bzero(&platformStorage, sizeof platformStorage);
 236
 237         ParseCmdLinArgs(argc, argv);
 238
 239         LogMsgIdent(mDNSResponderVersionString, "starting");
 240
 241         err = mDNS_Init(&mDNSRecord, &platformStorage, gRRCache, RR_CACHE_SIZE, mDNS_Init_AdvertiseLocalAddresses,
 242                                         mDNS_Init_NoInitCallback, mDNS_Init_NoInitCallbackContext);
 243
 244         if (mStatus_NoError == err)
 245                 err = udsserver_init();
 246
 247         Reconfigure(&mDNSRecord);
 248
 249         // Now that we're finished with anything privileged, switch over to running as "nobody"
 250         if (mStatus_NoError == err)
 251                 {
 252                 const struct passwd *pw = getpwnam("nobody");
 253                 if (pw != NULL)
 254                         setuid(pw->pw_uid);
 255                 else
 256                         LogMsg("WARNING: mdnsd continuing as root because user \"nobody\" does not exist");
 257                 }
 258
 259         if (mStatus_NoError == err)
 260                 err = MainLoop(&mDNSRecord);
 261
 262         LogMsgIdent(mDNSResponderVersionString, "stopping");
 263
 264         mDNS_Close(&mDNSRecord);
 265
 266         if (udsserver_exit() < 0)
 267                 LogMsg("ExitCallback: udsserver_exit failed");
 268
 269  #if MDNS_DEBUGMSGS > 0
 270         printf("mDNSResponder exiting normally with %ld\n", err);
 271  #endif
 272
 273         return err;
 274         }
 275
 276 //              uds_daemon support              ////////////////////////////////////////////////////////////
 277
 278 #if MDNS_MALLOC_DEBUGGING >= 2
 279 #define LogMalloc LogMsg
 280 #else
 281 #define LogMalloc(ARGS...) ((void)0)
 282 #endif
 283
 284 mStatus udsSupportAddFDToEventLoop(int fd, udsEventCallback callback, void *context)
 285 /* Support routine for uds_daemon.c */
 286         {
 287         // Depends on the fact that udsEventCallback == mDNSPosixEventCallback
 288         return mDNSPosixAddFDToEventLoop(fd, callback, context);
 289         }
 290
 291 mStatus udsSupportRemoveFDFromEventLoop(int fd)         // Note: This also CLOSES the file descriptor
 292         {
 293         mStatus err = mDNSPosixRemoveFDFromEventLoop(fd);
 294         close(fd);
 295         return err;
 296         }
 297
 298 mDNSexport void RecordUpdatedNiceLabel(mDNS *const m, mDNSs32 delay)
 299         {
 300         (void)m;
 301         (void)delay;
 302         // No-op, for now
 303         }
 304
 305 #if MACOSX_MDNS_MALLOC_DEBUGGING >= 1
 306
 307 void *mallocL(char *msg, unsigned int size)
 308         {
 309         unsigned long *mem = malloc(size+8);
 310         if (!mem)
 311                 {
 312                 LogMsg("malloc( %s : %d ) failed", msg, size);
 313                 return(NULL);
 314                 }
 315         else
 316                 {
 317                 LogMalloc("malloc( %s : %lu ) = %p", msg, size, &mem[2]);
 318                 mem[0] = 0xDEAD1234;
 319                 mem[1] = size;
 320                 //bzero(&mem[2], size);
 321                 memset(&mem[2], 0xFF, size);
 322 //              validatelists(&mDNSStorage);
 323                 return(&mem[2]);
 324                 }
 325         }
 326
 327 void freeL(char *msg, void *x)
 328         {
 329         if (!x)
 330                 LogMsg("free( %s @ NULL )!", msg);
 331         else
 332                 {
 333                 unsigned long *mem = ((unsigned long *)x) - 2;
 334                 if (mem[0] != 0xDEAD1234)
 335                         { LogMsg("free( %s @ %p ) !!!! NOT ALLOCATED !!!!", msg, &mem[2]); return; }
 336                 if (mem[1] > 8000)
 337                         { LogMsg("free( %s : %ld @ %p) too big!", msg, mem[1], &mem[2]); return; }
 338                 LogMalloc("free( %s : %ld @ %p)", msg, mem[1], &mem[2]);
 339                 //bzero(mem, mem[1]+8);
 340                 memset(mem, 0xDD, mem[1]+8);
 341 //              validatelists(&mDNSStorage);
 342                 free(mem);
 343                 }
 344         }
 345
 346 #endif // MACOSX_MDNS_MALLOC_DEBUGGING >= 1
 347
 348 // For convenience when using the "strings" command, this is the last thing in the file
 349 #if mDNSResponderVersion > 1
 350 mDNSexport const char mDNSResponderVersionString[] = "mDNSResponder-" STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ") ";
 351 #else
 352 mDNSexport const char mDNSResponderVersionString[] = "mDNSResponder (Engineering Build) (" __DATE__ " " __TIME__ ") ";
 353 #endif