mDNSPosix/PosixDaemon.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24
  25         File:           daemon.c
  26
  27         Contains:       main & associated Application layer for mDNSResponder on Linux.
  28
  29         Version:        1.0
  30         Tabs:           4 spaces
  31
  32     Change History (most recent first):
  33
  34 $Log: PosixDaemon.c,v $
  35 Revision 1.10  2004/06/08 04:59:40  cheshire
  36 Tidy up wording -- log messages are already prefixed with "mDNSResponder", so don't need to repeat it
  37
  38 Revision 1.9  2004/05/29 00:14:20  rpantos
  39 <rdar://problem/3508093> Runtime check to disable prod mdnsd on OS X.
  40
  41 Revision 1.8  2004/04/07 01:19:04  cheshire
  42 Hash slot value should be unsigned
  43
  44 Revision 1.7  2004/02/14 06:34:57  cheshire
  45 Use LogMsg instead of fprintf( stderr
  46
  47 Revision 1.6  2004/02/14 01:10:42  rpantos
  48 Allow daemon to run if 'nobody' is not defined, with a warning. (For Roku HD1000.)
  49
  50 Revision 1.5  2004/02/05 07:45:43  cheshire
  51 Add Log header
  52
  53 Revision 1.4  2004/01/28 21:14:23  cheshire
  54 Reconcile debug_mode and gDebugLogging into a single flag (mDNS_DebugMode)
  55
  56 Revision 1.3  2004/01/19 19:51:46  cheshire
  57 Fix compiler error (mixed declarations and code) on some versions of Linux
  58
  59 Revision 1.2  2003/12/11 03:03:51  rpantos
  60 Clean up mDNSPosix so that it builds on OS X again.
  61
  62 Revision 1.1  2003/12/08 20:47:02  rpantos
  63 Add support for mDNSResponder on Linux.
  64
  65 */
  66
  67 #include <stdio.h>
  68 #include <string.h>
  69 #include <unistd.h>
  70 #include <stdlib.h>
  71 #include <signal.h>
  72 #include <errno.h>
  73 #include <pwd.h>
  74 #include <sys/types.h>
  75
  76 #include "mDNSClientAPI.h"
  77 #include "mDNSDebug.h"
  78 #include "mDNSPosix.h"
  79 #include "uds_daemon.h"
  80
  81
  82 static void             ParseCmdLinArgs( int argc, char **argv);
  83 static void             DumpStateLog( mDNS *m);
  84 static mStatus  MainLoop( mDNS *m);
  85
  86
  87 #define RR_CACHE_SIZE 500
  88 static CacheRecord gRRCache[RR_CACHE_SIZE];
  89
  90 extern const char mDNSResponderVersionString[];
  91
  92 int             main( int argc, char **argv)
  93 {
  94         mDNS                                    mDNSRecord;
  95         mDNS_PlatformSupport    platformStorage;
  96         mStatus                                 err;
  97
  98         bzero( &mDNSRecord, sizeof mDNSRecord);
  99         bzero( &platformStorage, sizeof platformStorage);
 100
 101         ParseCmdLinArgs( argc, argv);
 102
 103         err = mDNS_Init( &mDNSRecord, &platformStorage, gRRCache, RR_CACHE_SIZE, mDNS_Init_AdvertiseLocalAddresses,
 104                                         mDNS_Init_NoInitCallback, mDNS_Init_NoInitCallbackContext);
 105
 106         if ( mStatus_NoError == err)
 107                 err = udsserver_init( &mDNSRecord);
 108
 109         // Now that we're finished with anything privileged, switch over to running as "nobody"
 110         if ( mStatus_NoError == err)
 111         {
 112                 const struct passwd *pw = getpwnam("nobody");
 113                 if ( pw != NULL)
 114                         setuid( pw->pw_uid);
 115                 else
 116                         LogMsg("WARNING: mdnsd continuing as root because user \"nobody\" does not exist");
 117         }
 118
 119         if ( mStatus_NoError == err)
 120                 err = MainLoop( &mDNSRecord);
 121
 122         mDNS_Close( &mDNSRecord);
 123
 124         if (udsserver_exit() < 0)
 125                 LogMsg("ExitCallback: udsserver_exit failed");
 126
 127  #if MDNS_DEBUGMSGS > 0
 128         printf( "mDNSResponder exiting normally with %ld\n", err);
 129  #endif
 130
 131         return err;
 132 }
 133
 134
 135 static void     ParseCmdLinArgs( int argc, char **argv)
 136 // Do appropriate things at startup with command line arguments. Calls exit() if unhappy.
 137 {
 138         if ( argc > 1)
 139         {
 140                 if ( 0 == strcmp( argv[1], "-debug"))
 141                 {
 142                         mDNS_DebugMode = mDNStrue;
 143                 }
 144                 else
 145                         printf( "Usage: mDNSResponder [-debug]\n");
 146         }
 147
 148         if ( !mDNS_DebugMode)
 149         {
 150                 int             result = daemon( 0, 0);
 151
 152                 if ( result != 0)
 153                 {
 154                         LogMsg("Could not run as daemon - exiting");
 155                         exit( result);
 156                 }
 157
 158 #if __APPLE__
 159                 {
 160                         LogMsg("The POSIX mDNSResponder should only be used on OS X for testing - exiting");
 161                         exit( -1);
 162                 }
 163 #endif
 164         }
 165 }
 166
 167
 168 static void             DumpStateLog( mDNS *m)
 169 // Dump a little log of what we've been up to.
 170 {
 171         mDNSu32 slot;
 172         CacheRecord *rr;
 173         mDNSu32 CacheUsed = 0, CacheActive = 0;
 174         mDNSs32 now = mDNSPlatformTimeNow();
 175
 176         LogMsgIdent(mDNSResponderVersionString, "---- BEGIN STATE LOG ----");
 177
 178         for (slot = 0; slot < CACHE_HASH_SLOTS; slot++)
 179                 {
 180                 mDNSu32 SlotUsed = 0;
 181                 for (rr = m->rrcache_hash[slot]; rr; rr=rr->next)
 182                         {
 183                         mDNSs32 remain = rr->resrec.rroriginalttl - (now - rr->TimeRcvd) / mDNSPlatformOneSecond;
 184                         CacheUsed++;
 185                         SlotUsed++;
 186                         if (rr->CRActiveQuestion) CacheActive++;
 187                         LogMsgNoIdent("%s%6ld %-6s%-6s%s", rr->CRActiveQuestion ? "*" : " ", remain, DNSTypeName(rr->resrec.rrtype),
 188                                 ((PosixNetworkInterface *)rr->resrec.InterfaceID)->intfName, GetRRDisplayString(m, rr));
 189                         usleep(1000);   // Limit rate a little so we don't flood syslog too fast
 190                         }
 191                 if (m->rrcache_used[slot] != SlotUsed)
 192                         LogMsgNoIdent("Cache use mismatch: rrcache_used[slot] is %lu, true count %lu", m->rrcache_used[slot], SlotUsed);
 193                 }
 194         if (m->rrcache_totalused != CacheUsed)
 195                 LogMsgNoIdent("Cache use mismatch: rrcache_totalused is %lu, true count %lu", m->rrcache_totalused, CacheUsed);
 196         if (m->rrcache_active != CacheActive)
 197                 LogMsgNoIdent("Cache use mismatch: rrcache_active is %lu, true count %lu", m->rrcache_active, CacheActive);
 198         LogMsgNoIdent("Cache currently contains %lu records; %lu referenced by active questions", CacheUsed, CacheActive);
 199
 200         udsserver_info();
 201
 202         LogMsgIdent(mDNSResponderVersionString, "----  END STATE LOG  ----");
 203 }
 204
 205 static mStatus  MainLoop( mDNS *m)
 206 // Loop until we quit.
 207 {
 208         sigset_t        signals;
 209         mDNSBool        gotData = mDNSfalse;
 210
 211         mDNSPosixListenForSignalInEventLoop( SIGINT);
 212         mDNSPosixListenForSignalInEventLoop( SIGTERM);
 213         mDNSPosixListenForSignalInEventLoop( SIGUSR1);
 214         mDNSPosixListenForSignalInEventLoop( SIGPIPE);
 215
 216         for ( ; ;)
 217         {
 218                 // Work out how long we expect to sleep before the next scheduled task
 219                 struct timeval  timeout;
 220                 mDNSs32                 ticks;
 221
 222                 // Only idle if we didn't find any data the last time around
 223                 if ( !gotData)
 224                 {
 225                         mDNSs32                 nextTimerEvent = mDNS_Execute(m);
 226
 227                         nextTimerEvent = udsserver_idle( nextTimerEvent);
 228
 229                         ticks = nextTimerEvent - mDNSPlatformTimeNow();
 230                         if (ticks < 1) ticks = 1;
 231                 }
 232                 else    // otherwise call EventLoop again with 0 timemout
 233                         ticks = 0;
 234
 235                 timeout.tv_sec = ticks / mDNSPlatformOneSecond;
 236                 timeout.tv_usec = (ticks % mDNSPlatformOneSecond) * 1000000 / mDNSPlatformOneSecond;
 237
 238                 (void) mDNSPosixRunEventLoopOnce( m, &timeout, &signals, &gotData);
 239
 240                 if ( sigismember( &signals, SIGUSR1))
 241                         DumpStateLog( m);
 242                 if ( sigismember( &signals, SIGPIPE))   // happens when we try to write to a dead client; death should be detected soon in request_callback() and cleaned up.
 243                         LogMsg("Received SIGPIPE - ignoring");
 244                 if ( sigismember( &signals, SIGINT) || sigismember( &signals, SIGTERM))
 245                         break;
 246         }
 247
 248         return EINTR;
 249 }
 250
 251
 252 //              uds_daemon support              ////////////////////////////////////////////////////////////
 253
 254 #if MDNS_MALLOC_DEBUGGING >= 2
 255 #define LogMalloc LogMsg
 256 #else
 257 #define LogMalloc(ARGS...) ((void)0)
 258 #endif
 259
 260
 261 mStatus udsSupportAddFDToEventLoop( int fd, udsEventCallback callback, void *context)
 262 /* Support routine for uds_daemon.c */
 263 {
 264         // Depends on the fact that udsEventCallback == mDNSPosixEventCallback
 265         return mDNSPosixAddFDToEventLoop( fd, callback, context);
 266 }
 267
 268 mStatus udsSupportRemoveFDFromEventLoop( int fd)
 269 {
 270         return mDNSPosixRemoveFDFromEventLoop( fd);
 271 }
 272
 273 #if MACOSX_MDNS_MALLOC_DEBUGGING >= 1
 274
 275 void *mallocL(char *msg, unsigned int size)
 276 {
 277         unsigned long *mem = malloc(size+8);
 278         if (!mem)
 279         {
 280                 LogMsg("malloc( %s : %d ) failed", msg, size);
 281                 return(NULL);
 282         }
 283         else
 284         {
 285                 LogMalloc("malloc( %s : %lu ) = %p", msg, size, &mem[2]);
 286                 mem[0] = 0xDEAD1234;
 287                 mem[1] = size;
 288                 //bzero(&mem[2], size);
 289                 memset(&mem[2], 0xFF, size);
 290 //              validatelists(&mDNSStorage);
 291                 return(&mem[2]);
 292         }
 293 }
 294
 295 void freeL(char *msg, void *x)
 296 {
 297         if (!x)
 298                 LogMsg("free( %s @ NULL )!", msg);
 299         else
 300         {
 301                 unsigned long *mem = ((unsigned long *)x) - 2;
 302                 if (mem[0] != 0xDEAD1234)
 303                         { LogMsg("free( %s @ %p ) !!!! NOT ALLOCATED !!!!", msg, &mem[2]); return; }
 304                 if (mem[1] > 8000)
 305                         { LogMsg("free( %s : %ld @ %p) too big!", msg, mem[1], &mem[2]); return; }
 306                 LogMalloc("free( %s : %ld @ %p)", msg, mem[1], &mem[2]);
 307                 //bzero(mem, mem[1]+8);
 308                 memset(mem, 0xDD, mem[1]+8);
 309 //              validatelists(&mDNSStorage);
 310                 free(mem);
 311         }
 312 }
 313
 314 #endif // MACOSX_MDNS_MALLOC_DEBUGGING >= 1
 315
 316
 317
 318 // For convenience when using the "strings" command, this is the last thing in the file
 319 #if mDNSResponderVersion > 1
 320 mDNSexport const char mDNSResponderVersionString[] = "mDNSResponder-" STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ") ";
 321 #else
 322 mDNSexport const char mDNSResponderVersionString[] = "mDNSResponder (Engineering Build) (" __DATE__ " " __TIME__ ") ";
 323 #endif