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 */ 22 23#if __APPLE__ 24// In Mac OS X 10.5 and later trying to use the daemon function gives a “‘daemon’ is deprecated” 25// error, which prevents compilation because we build with "-Werror". 26// Since this is supposed to be portable cross-platform code, we don't care that daemon is 27// deprecated on Mac OS X 10.5, so we use this preprocessor trick to eliminate the error message. 28#define daemon yes_we_know_that_daemon_is_deprecated_in_os_x_10_5_thankyou 29#endif 30 31#include <stdio.h> 32#include <string.h> 33#include <unistd.h> 34#include <stdlib.h> 35#include <signal.h> 36#include <errno.h> 37#include <fcntl.h> 38#include <pwd.h> 39#include <sys/types.h> 40 41#if __APPLE__ 42#undef daemon 43extern int daemon(int, int); 44#endif 45 46#include "mDNSEmbeddedAPI.h" 47#include "mDNSPosix.h" 48#include "mDNSUNP.h" // For daemon() 49#include "uds_daemon.h" 50#include "PlatformCommon.h" 51 52#define CONFIG_FILE "/etc/mdnsd.conf" 53static domainname DynDNSZone; // Default wide-area zone for service registration 54static domainname DynDNSHostname; 55 56#define RR_CACHE_SIZE 500 57static CacheEntity gRRCache[RR_CACHE_SIZE]; 58static mDNS_PlatformSupport PlatformStorage; 59 60mDNSlocal void mDNS_StatusCallback(mDNS *const m, mStatus result) 61{ 62 (void)m; // Unused 63 if (result == mStatus_NoError) 64 { 65 // On successful registration of dot-local mDNS host name, daemon may want to check if 66 // any name conflict and automatic renaming took place, and if so, record the newly negotiated 67 // name in persistent storage for next time. It should also inform the user of the name change. 68 // On Mac OS X we store the current dot-local mDNS host name in the SCPreferences store, 69 // and notify the user with a CFUserNotification. 70 } 71 else if (result == mStatus_ConfigChanged) 72 { 73 udsserver_handle_configchange(m); 74 } 75 else if (result == mStatus_GrowCache) 76 { 77 // Allocate another chunk of cache storage 78 CacheEntity *storage = malloc(sizeof(CacheEntity) * RR_CACHE_SIZE); 79 if (storage) mDNS_GrowCache(m, storage, RR_CACHE_SIZE); 80 } 81} 82 83// %%% Reconfigure() probably belongs in the platform support layer (mDNSPosix.c), not the daemon cde 84// -- all client layers running on top of mDNSPosix.c need to handle network configuration changes, 85// not only the Unix Domain Socket Daemon 86 87static void Reconfigure(mDNS *m) 88{ 89 mDNSAddr DynDNSIP; 90 const mDNSAddr dummy = { mDNSAddrType_IPv4, { { { 1, 1, 1, 1 } } } };; 91 mDNS_SetPrimaryInterfaceInfo(m, NULL, NULL, NULL); 92 if (ParseDNSServers(m, uDNS_SERVERS_FILE) < 0) 93 LogMsg("Unable to parse DNS server list. Unicast DNS-SD unavailable"); 94 ReadDDNSSettingsFromConfFile(m, CONFIG_FILE, &DynDNSHostname, &DynDNSZone, NULL); 95 mDNSPlatformSourceAddrForDest(&DynDNSIP, &dummy); 96 if (DynDNSHostname.c[0]) mDNS_AddDynDNSHostName(m, &DynDNSHostname, NULL, NULL); 97 if (DynDNSIP.type) mDNS_SetPrimaryInterfaceInfo(m, &DynDNSIP, NULL, NULL); 98 mDNS_ConfigChanged(m); 99} 100 101// Do appropriate things at startup with command line arguments. Calls exit() if unhappy. 102mDNSlocal void ParseCmdLinArgs(int argc, char **argv) 103{ 104 if (argc > 1) 105 { 106 if (0 == strcmp(argv[1], "-debug")) mDNS_DebugMode = mDNStrue; 107 else printf("Usage: %s [-debug]\n", argv[0]); 108 } 109 110 if (!mDNS_DebugMode) 111 { 112 int result = daemon(0, 0); 113 if (result != 0) { LogMsg("Could not run as daemon - exiting"); exit(result); } 114#if __APPLE__ 115 LogMsg("The POSIX mdnsd should only be used on OS X for testing - exiting"); 116 exit(-1); 117#endif 118 } 119} 120 121mDNSlocal void DumpStateLog(mDNS *const m) 122// Dump a little log of what we've been up to. 123{ 124 LogMsg("---- BEGIN STATE LOG ----"); 125 udsserver_info(m); 126 LogMsg("---- END STATE LOG ----"); 127} 128 129mDNSlocal mStatus MainLoop(mDNS *m) // Loop until we quit. 130{ 131 sigset_t signals; 132 mDNSBool gotData = mDNSfalse; 133 134 mDNSPosixListenForSignalInEventLoop(SIGINT); 135 mDNSPosixListenForSignalInEventLoop(SIGTERM); 136 mDNSPosixListenForSignalInEventLoop(SIGUSR1); 137 mDNSPosixListenForSignalInEventLoop(SIGPIPE); 138 mDNSPosixListenForSignalInEventLoop(SIGHUP) ; 139 140 for (; ;) 141 { 142 // Work out how long we expect to sleep before the next scheduled task 143 struct timeval timeout; 144 mDNSs32 ticks; 145 146 // Only idle if we didn't find any data the last time around 147 if (!gotData) 148 { 149 mDNSs32 nextTimerEvent = mDNS_Execute(m); 150 nextTimerEvent = udsserver_idle(nextTimerEvent); 151 ticks = nextTimerEvent - mDNS_TimeNow(m); 152 if (ticks < 1) ticks = 1; 153 } 154 else // otherwise call EventLoop again with 0 timemout 155 ticks = 0; 156 157 timeout.tv_sec = ticks / mDNSPlatformOneSecond; 158 timeout.tv_usec = (ticks % mDNSPlatformOneSecond) * 1000000 / mDNSPlatformOneSecond; 159 160 (void) mDNSPosixRunEventLoopOnce(m, &timeout, &signals, &gotData); 161 162 if (sigismember(&signals, SIGHUP )) Reconfigure(m); 163 if (sigismember(&signals, SIGUSR1)) DumpStateLog(m); 164 // SIGPIPE happens when we try to write to a dead client; death should be detected soon in request_callback() and cleaned up. 165 if (sigismember(&signals, SIGPIPE)) LogMsg("Received SIGPIPE - ignoring"); 166 if (sigismember(&signals, SIGINT) || sigismember(&signals, SIGTERM)) break; 167 } 168 return EINTR; 169} 170 171int main(int argc, char **argv) 172{ 173 mStatus err; 174 175 ParseCmdLinArgs(argc, argv); 176 177 LogMsg("%s starting", mDNSResponderVersionString); 178 179 err = mDNS_Init(&mDNSStorage, &PlatformStorage, gRRCache, RR_CACHE_SIZE, mDNS_Init_AdvertiseLocalAddresses, 180 mDNS_StatusCallback, mDNS_Init_NoInitCallbackContext); 181 182 if (mStatus_NoError == err) 183 err = udsserver_init(mDNSNULL, 0); 184 185 Reconfigure(&mDNSStorage); 186 187 // Now that we're finished with anything privileged, switch over to running as "nobody" 188 if (mStatus_NoError == err) 189 { 190 const struct passwd *pw = getpwnam("nobody"); 191 if (pw != NULL) 192 setuid(pw->pw_uid); 193 else 194 LogMsg("WARNING: mdnsd continuing as root because user \"nobody\" does not exist"); 195 } 196 197 if (mStatus_NoError == err) 198 err = MainLoop(&mDNSStorage); 199 200 LogMsg("%s stopping", mDNSResponderVersionString); 201 202 mDNS_Close(&mDNSStorage); 203 204 if (udsserver_exit() < 0) 205 LogMsg("ExitCallback: udsserver_exit failed"); 206 207 #if MDNS_DEBUGMSGS > 0 208 printf("mDNSResponder exiting normally with %ld\n", err); 209 #endif 210 211 return err; 212} 213 214// uds_daemon support //////////////////////////////////////////////////////////// 215 216mStatus udsSupportAddFDToEventLoop(int fd, udsEventCallback callback, void *context, void **platform_data) 217/* Support routine for uds_daemon.c */ 218{ 219 // Depends on the fact that udsEventCallback == mDNSPosixEventCallback 220 (void) platform_data; 221 return mDNSPosixAddFDToEventLoop(fd, callback, context); 222} 223 224int udsSupportReadFD(dnssd_sock_t fd, char *buf, int len, int flags, void *platform_data) 225{ 226 (void) platform_data; 227 return recv(fd, buf, len, flags); 228} 229 230mStatus udsSupportRemoveFDFromEventLoop(int fd, void *platform_data) // Note: This also CLOSES the file descriptor 231{ 232 mStatus err = mDNSPosixRemoveFDFromEventLoop(fd); 233 (void) platform_data; 234 close(fd); 235 return err; 236} 237 238mDNSexport void RecordUpdatedNiceLabel(mDNS *const m, mDNSs32 delay) 239{ 240 (void)m; 241 (void)delay; 242 // No-op, for now 243} 244 245#if _BUILDING_XCODE_PROJECT_ 246// If the process crashes, then this string will be magically included in the automatically-generated crash log 247const char *__crashreporter_info__ = mDNSResponderVersionString_SCCS + 5; 248asm (".desc ___crashreporter_info__, 0x10"); 249#endif 250 251// For convenience when using the "strings" command, this is the last thing in the file 252#if mDNSResponderVersion > 1 253mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder-" STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ")"; 254#elif MDNS_VERSIONSTR_NODTS 255mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder (Engineering Build)"; 256#else 257mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder (Engineering Build) (" __DATE__ " " __TIME__ ")"; 258#endif 259