/* -*- 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()
// Dump a little log of what we've been up to.
{
LogMsg("---- BEGIN STATE LOG ----");
udsserver_info();
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();
// 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(mDNSs32 delay)
{
(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
