diff options
Diffstat (limited to 'mDNSResponder/mDNSPosix/PosixDaemon.c')
| -rw-r--r-- | mDNSResponder/mDNSPosix/PosixDaemon.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/mDNSResponder/mDNSPosix/PosixDaemon.c b/mDNSResponder/mDNSPosix/PosixDaemon.c new file mode 100644 index 00000000..88b3292c --- /dev/null +++ b/mDNSResponder/mDNSPosix/PosixDaemon.c @@ -0,0 +1,258 @@ +/* -*- Mode: C; tab-width: 4 -*- + * + * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + + File: daemon.c + + Contains: main & associated Application layer for mDNSResponder on Linux. + + */ + +#if __APPLE__ +// In Mac OS X 10.5 and later trying to use the daemon function gives a “‘daemon’ is deprecated” +// error, which prevents compilation because we build with "-Werror". +// Since this is supposed to be portable cross-platform code, we don't care that daemon is +// deprecated on Mac OS X 10.5, so we use this preprocessor trick to eliminate the error message. +#define daemon yes_we_know_that_daemon_is_deprecated_in_os_x_10_5_thankyou +#endif + +#include <stdio.h> +#include <string.h> +#include <unistd.h> +#include <stdlib.h> +#include <signal.h> +#include <errno.h> +#include <fcntl.h> +#include <pwd.h> +#include <sys/types.h> + +#if __APPLE__ +#undef daemon +extern int daemon(int, int); +#endif + +#include "mDNSEmbeddedAPI.h" +#include "mDNSPosix.h" +#include "mDNSUNP.h" // For daemon() +#include "uds_daemon.h" +#include "PlatformCommon.h" + +#define CONFIG_FILE "/etc/mdnsd.conf" +static domainname DynDNSZone; // Default wide-area zone for service registration +static domainname DynDNSHostname; + +#define RR_CACHE_SIZE 500 +static CacheEntity gRRCache[RR_CACHE_SIZE]; +static mDNS_PlatformSupport PlatformStorage; + +mDNSlocal void mDNS_StatusCallback(mDNS *const m, mStatus result) +{ + (void)m; // Unused + if (result == mStatus_NoError) + { + // On successful registration of dot-local mDNS host name, daemon may want to check if + // any name conflict and automatic renaming took place, and if so, record the newly negotiated + // name in persistent storage for next time. It should also inform the user of the name change. + // On Mac OS X we store the current dot-local mDNS host name in the SCPreferences store, + // and notify the user with a CFUserNotification. + } + else if (result == mStatus_ConfigChanged) + { + udsserver_handle_configchange(m); + } + else if (result == mStatus_GrowCache) + { + // Allocate another chunk of cache storage + CacheEntity *storage = malloc(sizeof(CacheEntity) * RR_CACHE_SIZE); + if (storage) mDNS_GrowCache(m, storage, RR_CACHE_SIZE); + } +} + +// %%% Reconfigure() probably belongs in the platform support layer (mDNSPosix.c), not the daemon cde +// -- all client layers running on top of mDNSPosix.c need to handle network configuration changes, +// not only the Unix Domain Socket Daemon + +static void Reconfigure(mDNS *m) +{ + mDNSAddr DynDNSIP; + const mDNSAddr dummy = { mDNSAddrType_IPv4, { { { 1, 1, 1, 1 } } } };; + mDNS_SetPrimaryInterfaceInfo(m, NULL, NULL, NULL); + if (ParseDNSServers(m, uDNS_SERVERS_FILE) < 0) + LogMsg("Unable to parse DNS server list. Unicast DNS-SD unavailable"); + ReadDDNSSettingsFromConfFile(m, CONFIG_FILE, &DynDNSHostname, &DynDNSZone, NULL); + mDNSPlatformSourceAddrForDest(&DynDNSIP, &dummy); + if (DynDNSHostname.c[0]) mDNS_AddDynDNSHostName(m, &DynDNSHostname, NULL, NULL); + if (DynDNSIP.type) mDNS_SetPrimaryInterfaceInfo(m, &DynDNSIP, NULL, NULL); + mDNS_ConfigChanged(m); +} + +// Do appropriate things at startup with command line arguments. Calls exit() if unhappy. +mDNSlocal void ParseCmdLinArgs(int argc, char **argv) +{ + if (argc > 1) + { + if (0 == strcmp(argv[1], "-debug")) mDNS_DebugMode = mDNStrue; + else printf("Usage: %s [-debug]\n", argv[0]); + } + + if (!mDNS_DebugMode) + { + int result = daemon(0, 0); + if (result != 0) { LogMsg("Could not run as daemon - exiting"); exit(result); } +#if __APPLE__ + LogMsg("The POSIX mdnsd should only be used on OS X for testing - exiting"); + exit(-1); +#endif + } +} + +mDNSlocal void DumpStateLog(mDNS *const m) +// Dump a little log of what we've been up to. +{ + LogMsg("---- BEGIN STATE LOG ----"); + udsserver_info(m); + LogMsg("---- END STATE LOG ----"); +} + +mDNSlocal mStatus MainLoop(mDNS *m) // Loop until we quit. +{ + sigset_t signals; + mDNSBool gotData = mDNSfalse; + + mDNSPosixListenForSignalInEventLoop(SIGINT); + mDNSPosixListenForSignalInEventLoop(SIGTERM); + mDNSPosixListenForSignalInEventLoop(SIGUSR1); + mDNSPosixListenForSignalInEventLoop(SIGPIPE); + mDNSPosixListenForSignalInEventLoop(SIGHUP) ; + + for (; ;) + { + // Work out how long we expect to sleep before the next scheduled task + struct timeval timeout; + mDNSs32 ticks; + + // Only idle if we didn't find any data the last time around + if (!gotData) + { + mDNSs32 nextTimerEvent = mDNS_Execute(m); + nextTimerEvent = udsserver_idle(nextTimerEvent); + ticks = nextTimerEvent - mDNS_TimeNow(m); + if (ticks < 1) ticks = 1; + } + else // otherwise call EventLoop again with 0 timemout + ticks = 0; + + timeout.tv_sec = ticks / mDNSPlatformOneSecond; + timeout.tv_usec = (ticks % mDNSPlatformOneSecond) * 1000000 / mDNSPlatformOneSecond; + + (void) mDNSPosixRunEventLoopOnce(m, &timeout, &signals, &gotData); + + if (sigismember(&signals, SIGHUP )) Reconfigure(m); + if (sigismember(&signals, SIGUSR1)) DumpStateLog(m); + // SIGPIPE happens when we try to write to a dead client; death should be detected soon in request_callback() and cleaned up. + if (sigismember(&signals, SIGPIPE)) LogMsg("Received SIGPIPE - ignoring"); + if (sigismember(&signals, SIGINT) || sigismember(&signals, SIGTERM)) break; + } + return EINTR; +} + +int main(int argc, char **argv) +{ + mStatus err; + + ParseCmdLinArgs(argc, argv); + + LogMsg("%s starting", mDNSResponderVersionString); + + err = mDNS_Init(&mDNSStorage, &PlatformStorage, gRRCache, RR_CACHE_SIZE, mDNS_Init_AdvertiseLocalAddresses, + mDNS_StatusCallback, mDNS_Init_NoInitCallbackContext); + + if (mStatus_NoError == err) + err = udsserver_init(mDNSNULL, 0); + + Reconfigure(&mDNSStorage); + + // Now that we're finished with anything privileged, switch over to running as "nobody" + if (mStatus_NoError == err) + { + const struct passwd *pw = getpwnam("nobody"); + if (pw != NULL) + setuid(pw->pw_uid); + else + LogMsg("WARNING: mdnsd continuing as root because user \"nobody\" does not exist"); + } + + if (mStatus_NoError == err) + err = MainLoop(&mDNSStorage); + + LogMsg("%s stopping", mDNSResponderVersionString); + + mDNS_Close(&mDNSStorage); + + if (udsserver_exit() < 0) + LogMsg("ExitCallback: udsserver_exit failed"); + + #if MDNS_DEBUGMSGS > 0 + printf("mDNSResponder exiting normally with %ld\n", err); + #endif + + return err; +} + +// uds_daemon support //////////////////////////////////////////////////////////// + +mStatus udsSupportAddFDToEventLoop(int fd, udsEventCallback callback, void *context, void **platform_data) +/* Support routine for uds_daemon.c */ +{ + // Depends on the fact that udsEventCallback == mDNSPosixEventCallback + (void) platform_data; + return mDNSPosixAddFDToEventLoop(fd, callback, context); +} + +int udsSupportReadFD(dnssd_sock_t fd, char *buf, int len, int flags, void *platform_data) +{ + (void) platform_data; + return recv(fd, buf, len, flags); +} + +mStatus udsSupportRemoveFDFromEventLoop(int fd, void *platform_data) // Note: This also CLOSES the file descriptor +{ + mStatus err = mDNSPosixRemoveFDFromEventLoop(fd); + (void) platform_data; + close(fd); + return err; +} + +mDNSexport void RecordUpdatedNiceLabel(mDNS *const m, mDNSs32 delay) +{ + (void)m; + (void)delay; + // No-op, for now +} + +#if _BUILDING_XCODE_PROJECT_ +// If the process crashes, then this string will be magically included in the automatically-generated crash log +const char *__crashreporter_info__ = mDNSResponderVersionString_SCCS + 5; +asm (".desc ___crashreporter_info__, 0x10"); +#endif + +// For convenience when using the "strings" command, this is the last thing in the file +#if mDNSResponderVersion > 1 +mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder-" STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ")"; +#elif MDNS_VERSIONSTR_NODTS +mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder (Engineering Build)"; +#else +mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder (Engineering Build) (" __DATE__ " " __TIME__ ")"; +#endif |