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