mDNSPosix/PosixDaemon.c

   1 /* -*- Mode: C; tab-width: 4 -*-
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   3  * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved.
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  11  * http://www.opensource.apple.com/apsl/ and read it before using this
  12  * file.
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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 1.25  2005/01/27 20:01:50  cheshire
  32 udsSupportRemoveFDFromEventLoop() needs to close the file descriptor as well
  33
  34 Revision 1.24  2005/01/19 19:20:49  ksekar
  35 <rdar://problem/3960191> Need a way to turn off domain discovery
  36
  37 Revision 1.23  2004/12/16 20:17:11  cheshire
  38 <rdar://problem/3324626> Cache memory management improvements
  39
  40 Revision 1.22  2004/12/10 13:12:08  cheshire
  41 Create no-op function RecordUpdatedNiceLabel(), required by uds_daemon.c
  42
  43 Revision 1.21  2004/12/01 20:57:20  ksekar
  44 <rdar://problem/3873921> Wide Area Rendezvous must be split-DNS aware
  45
  46 Revision 1.20  2004/12/01 04:28:43  cheshire
  47 <rdar://problem/3872803> Darwin patches for Solaris and Suse
  48 Use version of daemon() provided in mDNSUNP.c instead of local copy
  49
  50 Revision 1.19  2004/12/01 03:30:29  cheshire
  51 <rdar://problem/3889346> Add Unicast DNS support to mDNSPosix
  52
  53 Revision 1.18  2004/11/30 22:45:59  cheshire
  54 Minor code tidying
  55
  56 Revision 1.17  2004/11/30 22:18:59  cheshire
  57 <rdar://problem/3889351> Posix needs to read the list of unicast DNS servers and set server list
  58
  59 Revision 1.16  2004/09/21 21:05:12      cheshire
  60 Move duplicate code out of mDNSMacOSX/daemon.c and mDNSPosix/PosixDaemon.c,
  61 into mDNSShared/uds_daemon.c
  62
  63 Revision 1.15  2004/09/17 01:08:53      cheshire
  64 Renamed mDNSClientAPI.h to mDNSEmbeddedAPI.h
  65   The name "mDNSClientAPI.h" is misleading to new developers looking at this code. The interfaces
  66   declared in that file are ONLY appropriate to single-address-space embedded applications.
  67   For clients on general-purpose computers, the interfaces defined in dns_sd.h should be used.
  68
  69 Revision 1.14  2004/09/16 00:24:49      cheshire
  70 <rdar://problem/3803162> Fix unsafe use of mDNSPlatformTimeNow()
  71
  72 Revision 1.13  2004/08/11 01:59:41      cheshire
  73 Remove "mDNS *globalInstance" parameter from udsserver_init()
  74
  75 Revision 1.12  2004/06/28 23:19:19      cheshire
  76 Fix "Daemon_Init declared but never defined" warning on Linux
  77
  78 Revision 1.11  2004/06/25 00:26:27      rpantos
  79 Changes to fix the Posix build on Solaris.
  80
  81 Revision 1.10  2004/06/08 04:59:40      cheshire
  82 Tidy up wording -- log messages are already prefixed with "mDNSResponder", so don't need to repeat it
  83
  84 Revision 1.9  2004/05/29 00:14:20  rpantos
  85 <rdar://problem/3508093> Runtime check to disable prod mdnsd on OS X.
  86
  87 Revision 1.8  2004/04/07 01:19:04  cheshire
  88 Hash slot value should be unsigned
  89
  90 Revision 1.7  2004/02/14 06:34:57  cheshire
  91 Use LogMsg instead of fprintf( stderr
  92
  93 Revision 1.6  2004/02/14 01:10:42  rpantos
  94 Allow daemon to run if 'nobody' is not defined, with a warning. (For Roku HD1000.)
  95
  96 Revision 1.5  2004/02/05 07:45:43  cheshire
  97 Add Log header
  98
  99 Revision 1.4  2004/01/28 21:14:23  cheshire
 100 Reconcile debug_mode and gDebugLogging into a single flag (mDNS_DebugMode)
 101
 102 Revision 1.3  2004/01/19 19:51:46  cheshire
 103 Fix compiler error (mixed declarations and code) on some versions of Linux
 104
 105 Revision 1.2  2003/12/11 03:03:51  rpantos
 106 Clean up mDNSPosix so that it builds on OS X again.
 107
 108 Revision 1.1  2003/12/08 20:47:02  rpantos
 109 Add support for mDNSResponder on Linux.
 110 */
 111
 112 #include <stdio.h>
 113 #include <string.h>
 114 #include <unistd.h>
 115 #include <stdlib.h>
 116 #include <signal.h>
 117 #include <errno.h>
 118 #include <fcntl.h>
 119 #include <pwd.h>
 120 #include <sys/types.h>
 121 #include <netinet/in.h>
 122 #include <arpa/inet.h>
 123
 124 #include "mDNSEmbeddedAPI.h"
 125 #include "mDNSDebug.h"
 126 #include "mDNSPosix.h"
 127 #include "uds_daemon.h"
 128 #include "PlatformCommon.h"
 129
 130 #define uDNS_SERVERS_FILE "/etc/resolv.conf"
 131
 132 #define CONFIG_FILE "/etc/mdnsd.conf"
 133 static domainname DynDNSZone;                // Default wide-area zone for service registration
 134 static domainname DynDNSHostname;
 135
 136 #define RR_CACHE_SIZE 500
 137 static CacheEntity gRRCache[RR_CACHE_SIZE];
 138
 139 extern const char mDNSResponderVersionString[];
 140
 141 static int ParseDNSServers(mDNS *m, const char *filePath)
 142         {
 143         char line[256];
 144         char nameserver[16];
 145         char keyword[10];
 146         int  numOfServers = 0;
 147         FILE *fp = fopen(filePath, "r");
 148         if (fp == NULL) return -1;
 149         while (fgets(line,sizeof(line),fp))
 150                 {
 151                 struct in_addr ina;
 152                 line[255]='\0';         // just to be safe
 153                 if (sscanf(line,"%10s %15s", keyword, nameserver) != 2) continue;       // it will skip whitespaces
 154                 if (strncmp(keyword,"nameserver",10)) continue;
 155                 if (inet_aton(nameserver, (struct in_addr *)&ina) != 0)
 156                         {
 157                         mDNSAddr DNSAddr;
 158                         DNSAddr.type = mDNSAddrType_IPv4;
 159                         DNSAddr.ip.v4.NotAnInteger = ina.s_addr;
 160                         mDNS_AddDNSServer(m, &DNSAddr, NULL);
 161                         numOfServers++;
 162                         }
 163                 }
 164         return (numOfServers > 0) ? 0 : -1;
 165         }
 166
 167 static void Reconfigure(mDNS *m)
 168         {
 169         mDNSAddr DynDNSIP;
 170         mDNS_SetPrimaryInterfaceInfo(m, NULL, NULL);
 171         mDNS_DeleteDNSServers(m);
 172         if (ParseDNSServers(m, uDNS_SERVERS_FILE) < 0)
 173                 LogMsg("Unable to parse DNS server list. Unicast DNS-SD unavailable");
 174         ReadDDNSSettingsFromConfFile(m, CONFIG_FILE, &DynDNSHostname, &DynDNSZone, NULL);
 175         FindDefaultRouteIP(&DynDNSIP);
 176         if (DynDNSHostname.c[0]) mDNS_AddDynDNSHostName(m, &DynDNSHostname, NULL, NULL);
 177         if (DynDNSIP.type)       mDNS_SetPrimaryInterfaceInfo(m, &DynDNSIP, NULL);
 178         }
 179
 180 // Do appropriate things at startup with command line arguments. Calls exit() if unhappy.
 181 static void ParseCmdLinArgs(int argc, char **argv)
 182         {
 183         if (argc > 1)
 184                 {
 185                 if (0 == strcmp(argv[1], "-debug")) mDNS_DebugMode = mDNStrue;
 186                 else printf("Usage: mDNSResponder [-debug]\n");
 187                 }
 188
 189         if (!mDNS_DebugMode)
 190                 {
 191                 int result = daemon(0, 0);
 192                 if (result != 0) { LogMsg("Could not run as daemon - exiting"); exit(result); }
 193 #if __APPLE__
 194                 LogMsg("The POSIX mDNSResponder should only be used on OS X for testing - exiting");
 195                 exit(-1);
 196 #endif
 197                 }
 198         }
 199
 200 static void             DumpStateLog(mDNS *const m)
 201 // Dump a little log of what we've been up to.
 202         {
 203         LogMsgIdent(mDNSResponderVersionString, "---- BEGIN STATE LOG ----");
 204         udsserver_info(m);
 205         LogMsgIdent(mDNSResponderVersionString, "----  END STATE LOG  ----");
 206         }
 207
 208 static mStatus  MainLoop(mDNS *m) // Loop until we quit.
 209         {
 210         sigset_t        signals;
 211         mDNSBool        gotData = mDNSfalse;
 212
 213         mDNSPosixListenForSignalInEventLoop(SIGINT);
 214         mDNSPosixListenForSignalInEventLoop(SIGTERM);
 215         mDNSPosixListenForSignalInEventLoop(SIGUSR1);
 216         mDNSPosixListenForSignalInEventLoop(SIGPIPE);
 217         mDNSPosixListenForSignalInEventLoop(SIGHUP) ;
 218
 219         for (; ;)
 220                 {
 221                 // Work out how long we expect to sleep before the next scheduled task
 222                 struct timeval  timeout;
 223                 mDNSs32                 ticks;
 224
 225                 // Only idle if we didn't find any data the last time around
 226                 if (!gotData)
 227                         {
 228                         mDNSs32                 nextTimerEvent = mDNS_Execute(m);
 229                         nextTimerEvent = udsserver_idle(nextTimerEvent);
 230                         ticks = nextTimerEvent - mDNS_TimeNow(m);
 231                         if (ticks < 1) ticks = 1;
 232                         }
 233                 else    // otherwise call EventLoop again with 0 timemout
 234                         ticks = 0;
 235
 236                 timeout.tv_sec = ticks / mDNSPlatformOneSecond;
 237                 timeout.tv_usec = (ticks % mDNSPlatformOneSecond) * 1000000 / mDNSPlatformOneSecond;
 238
 239                 (void) mDNSPosixRunEventLoopOnce(m, &timeout, &signals, &gotData);
 240
 241                 if (sigismember(&signals, SIGHUP )) Reconfigure(m);
 242                 if (sigismember(&signals, SIGUSR1)) DumpStateLog(m);
 243                 // SIGPIPE happens when we try to write to a dead client; death should be detected soon in request_callback() and cleaned up.
 244                 if (sigismember(&signals, SIGPIPE)) LogMsg("Received SIGPIPE - ignoring");
 245                 if (sigismember(&signals, SIGINT) || sigismember(&signals, SIGTERM)) break;
 246                 }
 247         return EINTR;
 248         }
 249
 250 int             main(int argc, char **argv)
 251         {
 252         #define mDNSRecord mDNSStorage
 253         mDNS_PlatformSupport    platformStorage;
 254         mStatus                                 err;
 255
 256         bzero(&mDNSRecord, sizeof mDNSRecord);
 257         bzero(&platformStorage, sizeof platformStorage);
 258
 259         ParseCmdLinArgs(argc, argv);
 260
 261         err = mDNS_Init(&mDNSRecord, &platformStorage, gRRCache, RR_CACHE_SIZE, mDNS_Init_AdvertiseLocalAddresses,
 262                                         mDNS_Init_NoInitCallback, mDNS_Init_NoInitCallbackContext);
 263
 264         if (mStatus_NoError == err)
 265                 err = udsserver_init();
 266
 267         Reconfigure(&mDNSRecord);
 268
 269         // Now that we're finished with anything privileged, switch over to running as "nobody"
 270         if (mStatus_NoError == err)
 271                 {
 272                 const struct passwd *pw = getpwnam("nobody");
 273                 if (pw != NULL)
 274                         setuid(pw->pw_uid);
 275                 else
 276                         LogMsg("WARNING: mdnsd continuing as root because user \"nobody\" does not exist");
 277                 }
 278
 279         if (mStatus_NoError == err)
 280                 err = MainLoop(&mDNSRecord);
 281
 282         mDNS_Close(&mDNSRecord);
 283
 284         if (udsserver_exit() < 0)
 285                 LogMsg("ExitCallback: udsserver_exit failed");
 286
 287  #if MDNS_DEBUGMSGS > 0
 288         printf("mDNSResponder exiting normally with %ld\n", err);
 289  #endif
 290
 291         return err;
 292         }
 293
 294 //              uds_daemon support              ////////////////////////////////////////////////////////////
 295
 296 #if MDNS_MALLOC_DEBUGGING >= 2
 297 #define LogMalloc LogMsg
 298 #else
 299 #define LogMalloc(ARGS...) ((void)0)
 300 #endif
 301
 302 mStatus udsSupportAddFDToEventLoop(int fd, udsEventCallback callback, void *context)
 303 /* Support routine for uds_daemon.c */
 304         {
 305         // Depends on the fact that udsEventCallback == mDNSPosixEventCallback
 306         return mDNSPosixAddFDToEventLoop(fd, callback, context);
 307         }
 308
 309 mStatus udsSupportRemoveFDFromEventLoop(int fd)         // Note: This also CLOSES the file descriptor
 310         {
 311         return mDNSPosixRemoveFDFromEventLoop(fd);
 312         close(fd);
 313         }
 314
 315 mDNSexport void RecordUpdatedNiceLabel(mDNS *const m, mDNSs32 delay)
 316         {
 317         (void)m;
 318         (void)delay;
 319         // No-op, for now
 320         }
 321
 322 #if MACOSX_MDNS_MALLOC_DEBUGGING >= 1
 323
 324 void *mallocL(char *msg, unsigned int size)
 325         {
 326         unsigned long *mem = malloc(size+8);
 327         if (!mem)
 328                 {
 329                 LogMsg("malloc( %s : %d ) failed", msg, size);
 330                 return(NULL);
 331                 }
 332         else
 333                 {
 334                 LogMalloc("malloc( %s : %lu ) = %p", msg, size, &mem[2]);
 335                 mem[0] = 0xDEAD1234;
 336                 mem[1] = size;
 337                 //bzero(&mem[2], size);
 338                 memset(&mem[2], 0xFF, size);
 339 //              validatelists(&mDNSStorage);
 340                 return(&mem[2]);
 341                 }
 342         }
 343
 344 void freeL(char *msg, void *x)
 345         {
 346         if (!x)
 347                 LogMsg("free( %s @ NULL )!", msg);
 348         else
 349                 {
 350                 unsigned long *mem = ((unsigned long *)x) - 2;
 351                 if (mem[0] != 0xDEAD1234)
 352                         { LogMsg("free( %s @ %p ) !!!! NOT ALLOCATED !!!!", msg, &mem[2]); return; }
 353                 if (mem[1] > 8000)
 354                         { LogMsg("free( %s : %ld @ %p) too big!", msg, mem[1], &mem[2]); return; }
 355                 LogMalloc("free( %s : %ld @ %p)", msg, mem[1], &mem[2]);
 356                 //bzero(mem, mem[1]+8);
 357                 memset(mem, 0xDD, mem[1]+8);
 358 //              validatelists(&mDNSStorage);
 359                 free(mem);
 360                 }
 361         }
 362
 363 #endif // MACOSX_MDNS_MALLOC_DEBUGGING >= 1
 364
 365 // For convenience when using the "strings" command, this is the last thing in the file
 366 #if mDNSResponderVersion > 1
 367 mDNSexport const char mDNSResponderVersionString[] = "mDNSResponder-" STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ") ";
 368 #else
 369 mDNSexport const char mDNSResponderVersionString[] = "mDNSResponder (Engineering Build) (" __DATE__ " " __TIME__ ") ";
 370 #endif