daemon.c   [plain text]

/* -*- Mode: C; tab-width: 4 -*-
 *
 * Copyright (c) 2002-2011 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.
 *
 * Formatting notes:
 * This code follows the "Whitesmiths style" C indentation rules. Plenty of discussion
 * on C indentation can be found on the web, such as <http://www.kafejo.com/komp/1tbs.htm>,
 * but for the sake of brevity here I will say just this: Curly braces are not syntactially
 * part of an "if" statement; they are the beginning and ending markers of a compound statement;
 * therefore common sense dictates that if they are part of a compound statement then they
 * should be indented to the same level as everything else in that compound statement.
 * Indenting curly braces at the same level as the "if" implies that curly braces are
 * part of the "if", which is false. (This is as misleading as people who write "char* x,y;"
 * thinking that variables x and y are both of type "char*" -- and anyone who doesn't
 * understand why variable y is not of type "char*" just proves the point that poor code
 * layout leads people to unfortunate misunderstandings about how the C language really works.)
 */

// We set VERSION_MIN_REQUIRED to 10.4 to avoid "bootstrap_register is deprecated" warnings from bootstrap.h
#define MAC_OS_X_VERSION_MIN_REQUIRED MAC_OS_X_VERSION_10_4

#include <mach/mach.h>
#include <mach/mach_error.h>
#include <servers/bootstrap.h>
#include <sys/types.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <paths.h>
#include <fcntl.h>
#include <launch.h>
#include <pwd.h>
#include <sys/event.h>
#include <pthread.h>
#include <sandbox.h>
#include <SystemConfiguration/SCPreferencesSetSpecific.h>
#include <SystemConfiguration/SCDynamicStoreCopyDHCPInfo.h>

#if TARGET_OS_EMBEDDED
#include <bootstrap_priv.h>

#define bootstrap_register(A,B,C) bootstrap_register2((A),(B),(C),0)
#endif

#include "DNSServiceDiscoveryRequestServer.h"
#include "DNSServiceDiscoveryReply.h"

#include "uDNS.h"
#include "DNSCommon.h"
#include "mDNSMacOSX.h"				// Defines the specific types needed to run mDNS on this platform

#include "uds_daemon.h"				// Interface to the server side implementation of dns_sd.h

#include <DNSServiceDiscovery/DNSServiceDiscovery.h>
#include "helper.h"
#include "safe_vproc.h"

//*************************************************************************************************************
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark - Globals
#endif

static mDNS_PlatformSupport PlatformStorage;

// Start off with a default cache of 16K (99 records)
// Each time we grow the cache we add another 99 records
// 99 * 164 = 16236 bytes.
// This fits in four 4kB pages, with 148 bytes spare for memory block headers and similar overhead
#define RR_CACHE_SIZE ((16*1024) / sizeof(CacheRecord))
static CacheEntity rrcachestorage[RR_CACHE_SIZE];

static const char kmDNSBootstrapName[] = "com.apple.mDNSResponderRestart";
static mach_port_t m_port            = MACH_PORT_NULL;

#ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
mDNSlocal void PrepareForIdle(void *m_param);
#else // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
static mach_port_t client_death_port = MACH_PORT_NULL;
static mach_port_t signal_port       = MACH_PORT_NULL;
#endif // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

static mach_port_t server_priv_port  = MACH_PORT_NULL;

static dnssd_sock_t *launchd_fds = mDNSNULL;
static mDNSu32 launchd_fds_count = 0;

// mDNS Mach Message Timeout, in milliseconds.
// We need this to be short enough that we don't deadlock the mDNSResponder if a client
// fails to service its mach message queue, but long enough to give a well-written
// client a chance to service its mach message queue without getting cut off.
// Empirically, 50ms seems to work, so we set the timeout to 250ms to give
// even extra-slow clients a fair chance before we cut them off.
#define MDNS_MM_TIMEOUT 250

static int restarting_via_mach_init = 0;	// Used on Jaguar/Panther when daemon is started via mach_init mechanism
static int started_via_launchdaemon = 0;	// Indicates we're running on Tiger or later, where daemon is managed by launchd
static mDNSBool advertise = mDNS_Init_AdvertiseLocalAddresses; // By default, advertise addresses (& other records) via multicast

extern mDNSBool StrictUnicastOrdering;
extern mDNSBool AlwaysAppendSearchDomains;

//*************************************************************************************************************
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark -
#pragma mark - Active client list structures
#endif

typedef struct DNSServiceDomainEnumeration_struct DNSServiceDomainEnumeration;
struct DNSServiceDomainEnumeration_struct
	{
	DNSServiceDomainEnumeration *next;
	mach_port_t ClientMachPort;
	DNSQuestion dom;	// Question asking for domains
	DNSQuestion def;	// Question asking for default domain
	};

typedef struct DNSServiceBrowserResult_struct DNSServiceBrowserResult;
struct DNSServiceBrowserResult_struct
	{
	DNSServiceBrowserResult *next;
	int resultType;
	domainname result;
	};

typedef struct DNSServiceBrowser_struct DNSServiceBrowser;

typedef struct DNSServiceBrowserQuestion
	{
	struct DNSServiceBrowserQuestion *next;
	DNSQuestion q;
    domainname domain;
	} DNSServiceBrowserQuestion;

struct DNSServiceBrowser_struct
	{
	DNSServiceBrowser *next;
	mach_port_t ClientMachPort;
	DNSServiceBrowserQuestion *qlist;
	DNSServiceBrowserResult *results;
	mDNSs32 lastsuccess;
    mDNSBool DefaultDomain;                // was the browse started on an explicit domain?
    domainname type;                       // registration type
	};

typedef struct DNSServiceResolver_struct DNSServiceResolver;
struct DNSServiceResolver_struct
	{
	DNSServiceResolver *next;
	mach_port_t ClientMachPort;
	ServiceInfoQuery q;
	ServiceInfo      i;
	mDNSs32          ReportTime;
	};

// A single registered service: ServiceRecordSet + bookkeeping
// Note that we duplicate some fields from parent DNSServiceRegistration object
// to facilitate cleanup, when instances and parent may be deallocated at different times.
typedef struct ServiceInstance
	{
    struct ServiceInstance *next;
	mach_port_t ClientMachPort;
    mDNSBool autoname;			// Set if this name is tied to the Computer Name
    mDNSBool renameonmemfree;	// Set if we just got a name conflict and now need to automatically pick a new name
    domainlabel name;
    domainname domain;
    ServiceRecordSet srs;
	// Don't add any fields after ServiceRecordSet.
	// This is where the implicit extra space goes if we allocate an oversized ServiceRecordSet object
	} ServiceInstance;

// A client-created service.  May reference several ServiceInstance objects if default
// settings cause registration in multiple domains.
typedef struct DNSServiceRegistration
	{
    struct DNSServiceRegistration *next;
	mach_port_t ClientMachPort;
    mDNSBool DefaultDomain;
    mDNSBool autoname;
    size_t rdsize;
    int NumSubTypes;
    char regtype[MAX_ESCAPED_DOMAIN_NAME]; // for use in AllocateSubtypes
    domainlabel name;  // used only if autoname is false
    domainname type;
    mDNSIPPort port;
    unsigned char txtinfo[1024];
    size_t txt_len;
    uint32_t NextRef;
    ServiceInstance *regs;
	} DNSServiceRegistration;

static DNSServiceDomainEnumeration *DNSServiceDomainEnumerationList = NULL;
static DNSServiceBrowser           *DNSServiceBrowserList           = NULL;
static DNSServiceResolver          *DNSServiceResolverList          = NULL;
static DNSServiceRegistration      *DNSServiceRegistrationList      = NULL;

// We keep a list of client-supplied event sources in KQSocketEventSource records
typedef struct KQSocketEventSource
	{
	struct  KQSocketEventSource *next;
	int                         fd;
	KQueueEntry                 kqs;
	} KQSocketEventSource;

static KQSocketEventSource *gEventSources;

//*************************************************************************************************************
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark -
#pragma mark - General Utility Functions
#endif

#if APPLE_OSX_mDNSResponder && MACOSX_MDNS_MALLOC_DEBUGGING

char _malloc_options[] = "AXZ";

mDNSexport void LogMemCorruption(const char *format, ...)
	{
	char buffer[512];
	va_list ptr;
	va_start(ptr,format);
	buffer[mDNS_vsnprintf((char *)buffer, sizeof(buffer), format, ptr)] = 0;
	va_end(ptr);
	LogMsg("!!!! %s !!!!", buffer);
	NotifyOfElusiveBug("Memory Corruption", buffer);
#if ForceAlerts
	*(long*)0 = 0;	// Trick to crash and get a stack trace right here, if that's what we want
#endif
	}

mDNSlocal void validatelists(mDNS *const m)
	{
	// Check local lists
	KQSocketEventSource *k;
	for (k = gEventSources; k; k=k->next)
		if (k->next == (KQSocketEventSource *)~0 || k->fd < 0)
			LogMemCorruption("gEventSources: %p is garbage (%d)", k, k->fd);

	// Check Mach client lists
	DNSServiceDomainEnumeration *e;
	for (e = DNSServiceDomainEnumerationList; e; e=e->next)
		if (e->next == (DNSServiceDomainEnumeration *)~0 || e->ClientMachPort == 0 || e->ClientMachPort == (mach_port_t)~0)
			LogMemCorruption("DNSServiceDomainEnumerationList: %p is garbage (%X)", e, e->ClientMachPort);

	DNSServiceBrowser           *b;
	for (b = DNSServiceBrowserList; b; b=b->next)
		if (b->next == (DNSServiceBrowser *)~0 || b->ClientMachPort == 0 || b->ClientMachPort == (mach_port_t)~0)
			LogMemCorruption("DNSServiceBrowserList: %p is garbage (%X)", b, b->ClientMachPort);

	DNSServiceResolver          *l;
	for (l = DNSServiceResolverList; l; l=l->next)
		if (l->next == (DNSServiceResolver *)~0 || l->ClientMachPort == 0 || l->ClientMachPort == (mach_port_t)~0)
			LogMemCorruption("DNSServiceResolverList: %p is garbage (%X)", l, l->ClientMachPort);

	DNSServiceRegistration      *r;
	for (r = DNSServiceRegistrationList; r; r=r->next)
		if (r->next == (DNSServiceRegistration *)~0 || r->ClientMachPort == 0 || r->ClientMachPort == (mach_port_t)~0)
			LogMemCorruption("DNSServiceRegistrationList: %p is garbage (%X)", r, r->ClientMachPort);

	// Check Unix Domain Socket client lists (uds_daemon.c)
	uds_validatelists();

	// Check core mDNS lists
	AuthRecord                  *rr;
	for (rr = m->ResourceRecords; rr; rr=rr->next)
		{
		if (rr->next == (AuthRecord *)~0 || rr->resrec.RecordType == 0 || rr->resrec.RecordType == 0xFF)
			LogMemCorruption("ResourceRecords list: %p is garbage (%X)", rr, rr->resrec.RecordType);
		if (rr->resrec.name != &rr->namestorage)
			LogMemCorruption("ResourceRecords list: %p name %p does not point to namestorage %p %##s",
				rr, rr->resrec.name->c, rr->namestorage.c, rr->namestorage.c);
		}

	for (rr = m->DuplicateRecords; rr; rr=rr->next)
		if (rr->next == (AuthRecord *)~0 || rr->resrec.RecordType == 0 || rr->resrec.RecordType == 0xFF)
			LogMemCorruption("DuplicateRecords list: %p is garbage (%X)", rr, rr->resrec.RecordType);

	rr = m->NewLocalRecords;
	if (rr)
		if (rr->next == (AuthRecord *)~0 || rr->resrec.RecordType == 0 || rr->resrec.RecordType == 0xFF)
			LogMemCorruption("NewLocalRecords: %p is garbage (%X)", rr, rr->resrec.RecordType);

	rr = m->CurrentRecord;
	if (rr)
		if (rr->next == (AuthRecord *)~0 || rr->resrec.RecordType == 0 || rr->resrec.RecordType == 0xFF)
			LogMemCorruption("CurrentRecord: %p is garbage (%X)", rr, rr->resrec.RecordType);

	DNSQuestion                 *q;
	for (q = m->Questions; q; q=q->next)
		if (q->next == (DNSQuestion*)~0 || q->ThisQInterval == (mDNSs32)~0)
			LogMemCorruption("Questions list: %p is garbage (%lX %p)", q, q->ThisQInterval, q->next);

	CacheGroup                  *cg;
	CacheRecord                 *cr;
	mDNSu32 slot;
	FORALL_CACHERECORDS(slot, cg, cr)
		{
		if (cr->resrec.RecordType == 0 || cr->resrec.RecordType == 0xFF)
			LogMemCorruption("Cache slot %lu: %p is garbage (%X)", slot, cr, cr->resrec.RecordType);
		if (cr->CRActiveQuestion)
			{
			for (q = m->Questions; q; q=q->next) if (q == cr->CRActiveQuestion) break;
			if (!q) LogMemCorruption("Cache slot %lu: CRActiveQuestion %p not in m->Questions list %s", slot, cr->CRActiveQuestion, CRDisplayString(m, cr));
			}
		}

	// Check core uDNS lists
	udns_validatelists(m);

	// Check platform-layer lists
	NetworkInterfaceInfoOSX     *i;
	for (i = m->p->InterfaceList; i; i = i->next)
		if (i->next == (NetworkInterfaceInfoOSX *)~0 || !i->m || i->m == (mDNS *)~0)
			LogMemCorruption("m->p->InterfaceList: %p is garbage (%p)", i, i->ifinfo.ifname);

	ClientTunnel *t;
	for (t = m->TunnelClients; t; t=t->next)
		if (t->next == (ClientTunnel *)~0 || t->dstname.c[0] > 63)
			LogMemCorruption("m->TunnelClients: %p is garbage (%d)", t, t->dstname.c[0]);
	}

mDNSexport void *mallocL(char *msg, unsigned int size)
	{
	// Allocate space for two words of sanity checking data before the requested block
	mDNSu32 *mem = malloc(sizeof(mDNSu32) * 2 + size);
	if (!mem)
		{ LogMsg("malloc( %s : %d ) failed", msg, size); return(NULL); }
	else
		{
		if      (size > 24000)                      LogMsg("malloc( %s : %lu ) = %p suspiciously large", msg, size, &mem[2]);
		else if (MACOSX_MDNS_MALLOC_DEBUGGING >= 2) LogMsg("malloc( %s : %lu ) = %p",                    msg, size, &mem[2]);
		mem[0] = 0xDEAD1234;
		mem[1] = size;
		//mDNSPlatformMemZero(&mem[2], size);
		memset(&mem[2], 0xFF, size);
		validatelists(&mDNSStorage);
		return(&mem[2]);
		}
	}

mDNSexport void freeL(char *msg, void *x)
	{
	if (!x)
		LogMsg("free( %s @ NULL )!", msg);
	else
		{
		mDNSu32 *mem = ((mDNSu32 *)x) - 2;
		if      (mem[0] != 0xDEAD1234)            { LogMsg("free( %s @ %p ) !!!! NOT ALLOCATED !!!!", msg, &mem[2]); return; }
		if      (mem[1] > 24000)                    LogMsg("free( %s : %ld @ %p) suspiciously large", msg, mem[1], &mem[2]);
		else if (MACOSX_MDNS_MALLOC_DEBUGGING >= 2) LogMsg("free( %s : %ld @ %p)",                    msg, mem[1], &mem[2]);
		//mDNSPlatformMemZero(mem, sizeof(mDNSu32) * 2 + mem[1]);
		memset(mem, 0xFF, sizeof(mDNSu32) * 2 + mem[1]);
		validatelists(&mDNSStorage);
		free(mem);
		}
	}

#endif

//*************************************************************************************************************
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark -
#pragma mark - Mach client request handlers
#endif

//*************************************************************************************************************
// Client Death Detection

// This gets called after ALL constituent records of the Service Record Set have been deregistered
mDNSlocal void FreeServiceInstance(ServiceInstance *x)
	{
	ServiceRecordSet *s = &x->srs;
	ExtraResourceRecord *e = x->srs.Extras, *tmp;
	
	while (e)
		{
		e->r.RecordContext = e;
		tmp = e;
		e = e->next;
		FreeExtraRR(&mDNSStorage, &tmp->r, mStatus_MemFree);
		}
	
	if (s->RR_TXT.resrec.rdata != &s->RR_TXT.rdatastorage)
		freeL("TXT RData", s->RR_TXT.resrec.rdata);

	if (s->SubTypes) freeL("ServiceSubTypes", s->SubTypes);
	freeL("ServiceInstance", x);
	}

// AbortClient finds whatever client is identified by the given Mach port,
// stops whatever operation that client was doing, and frees its memory.
// In the case of a service registration, the actual freeing may be deferred
// until we get the mStatus_MemFree message, if necessary
mDNSlocal void AbortClient(mach_port_t ClientMachPort, void *m)
	{
	DNSServiceDomainEnumeration **e = &DNSServiceDomainEnumerationList;
	DNSServiceBrowser           **b = &DNSServiceBrowserList;
	DNSServiceResolver          **l = &DNSServiceResolverList;
	DNSServiceRegistration      **r = &DNSServiceRegistrationList;

	while (*e && (*e)->ClientMachPort != ClientMachPort) e = &(*e)->next;
	if (*e)
		{
		DNSServiceDomainEnumeration *x = *e;
		*e = (*e)->next;
		if (m && m != x)
			LogMsg("%5d: DNSServiceDomainEnumeration(%##s) STOP; WARNING m %p != x %p", ClientMachPort, x->dom.qname.c, m, x);
		else LogOperation("%5d: DNSServiceDomainEnumeration(%##s) STOP", ClientMachPort, x->dom.qname.c);
		mDNS_StopGetDomains(&mDNSStorage, &x->dom);
		mDNS_StopGetDomains(&mDNSStorage, &x->def);
		freeL("DNSServiceDomainEnumeration", x);
		return;
		}

	while (*b && (*b)->ClientMachPort != ClientMachPort) b = &(*b)->next;
	if (*b)
		{
		DNSServiceBrowser *x = *b;
		DNSServiceBrowserQuestion *freePtr, *qptr = x->qlist;
		*b = (*b)->next;
		while (qptr)
			{
			if (m && m != x)
				LogMsg("%5d: DNSServiceBrowse(%##s) STOP; WARNING m %p != x %p", ClientMachPort, qptr->q.qname.c, m, x);
			else LogOperation("%5d: DNSServiceBrowse(%##s) STOP", ClientMachPort, qptr->q.qname.c);
			mDNS_StopBrowse(&mDNSStorage, &qptr->q);
			freePtr = qptr;
			qptr = qptr->next;
			freeL("DNSServiceBrowserQuestion", freePtr);
			}
		while (x->results)
			{
			DNSServiceBrowserResult *t = x->results;
			x->results = x->results->next;
			freeL("DNSServiceBrowserResult", t);
			}
		freeL("DNSServiceBrowser", x);
		return;
		}

	while (*l && (*l)->ClientMachPort != ClientMachPort) l = &(*l)->next;
	if (*l)
		{
		DNSServiceResolver *x = *l;
		*l = (*l)->next;
		if (m && m != x)
			LogMsg("%5d: DNSServiceResolve(%##s) STOP; WARNING m %p != x %p", ClientMachPort, x->i.name.c, m, x);
		else LogOperation("%5d: DNSServiceResolve(%##s) STOP", ClientMachPort, x->i.name.c);
		mDNS_StopResolveService(&mDNSStorage, &x->q);
		freeL("DNSServiceResolver", x);
		return;
		}

	while (*r && (*r)->ClientMachPort != ClientMachPort) r = &(*r)->next;
	if (*r)
		{
		ServiceInstance *si = NULL;
		DNSServiceRegistration *x = *r;
		*r = (*r)->next;

		si = x->regs;
		while (si)
			{
			ServiceInstance *instance = si;
			si = si->next;
			instance->renameonmemfree = mDNSfalse;
			if (m && m != x) LogMsg("%5d: DNSServiceRegistration(%##s, %u) STOP; WARNING m %p != x %p", ClientMachPort, instance->srs.RR_SRV.resrec.name->c, SRS_PORT(&instance->srs), m, x);
			else LogOperation("%5d: DNSServiceRegistration(%##s, %u) STOP", ClientMachPort, instance->srs.RR_SRV.resrec.name->c, SRS_PORT(&instance->srs));

			// If mDNS_DeregisterService() returns mStatus_NoError, that means that the service was found in the list,
			// is sending its goodbye packet, and we'll get an mStatus_MemFree message when we can free the memory.
			// If mDNS_DeregisterService() returns an error, it means that the service had already been removed from
			// the list, so we should go ahead and free the memory right now
			if (mDNS_DeregisterService(&mDNSStorage, &instance->srs)) FreeServiceInstance(instance); // FreeServiceInstance invalidates pointer
			}
		x->regs = NULL;
		freeL("DNSServiceRegistration", x);
		return;
		}

	LogMsg("%5d: died or deallocated, but no record of client can be found!", ClientMachPort);
	}

#define AbortBlockedClient(C,MSG,M) AbortClientWithLogMessage((C), "stopped accepting Mach messages", " (" MSG ")", (M))

mDNSlocal void AbortClientWithLogMessage(mach_port_t c, char *reason, char *msg, void *m)
	{
	DNSServiceDomainEnumeration *e = DNSServiceDomainEnumerationList;
	DNSServiceBrowser           *b = DNSServiceBrowserList;
	DNSServiceResolver          *l = DNSServiceResolverList;
	DNSServiceRegistration      *r = DNSServiceRegistrationList;
	DNSServiceBrowserQuestion   *qptr;

	while (e && e->ClientMachPort != c) e = e->next;
	while (b && b->ClientMachPort != c) b = b->next;
	while (l && l->ClientMachPort != c) l = l->next;
	while (r && r->ClientMachPort != c) r = r->next;

	if      (e) LogMsg("%5d: DomainEnumeration(%##s) %s%s",                   c, e->dom.qname.c,                reason, msg);
	else if (b)
			{
			for (qptr = b->qlist; qptr; qptr = qptr->next)
				LogMsg("%5d: Browser(%##s) %s%s",                             c, qptr->q.qname.c,               reason, msg);
			}
	else if (l) LogMsg("%5d: Resolver(%##s) %s%s",                            c, l->i.name.c,                   reason, msg);
	else if (r)
			{
			ServiceInstance *si;
			for (si = r->regs; si; si = si->next)
				LogMsg("%5d: Registration(%##s) %s%s",                        c, si->srs.RR_SRV.resrec.name->c, reason, msg);
			}
	else        LogMsg("%5d: (%s) %s, but no record of client can be found!", c,                                reason, msg);

	AbortClient(c, m);
	}

mDNSlocal mDNSBool CheckForExistingClient(mach_port_t c)
	{
	DNSServiceDomainEnumeration *e = DNSServiceDomainEnumerationList;
	DNSServiceBrowser           *b = DNSServiceBrowserList;
	DNSServiceResolver          *l = DNSServiceResolverList;
	DNSServiceRegistration      *r = DNSServiceRegistrationList;
	DNSServiceBrowserQuestion   *qptr;

	while (e && e->ClientMachPort != c) e = e->next;
	while (b && b->ClientMachPort != c) b = b->next;
	while (l && l->ClientMachPort != c) l = l->next;
	while (r && r->ClientMachPort != c) r = r->next;
	if (e) LogMsg("%5d: DomainEnumeration(%##s) already exists!", c, e->dom.qname.c);
	if (b)
		{
		for (qptr = b->qlist; qptr; qptr = qptr->next)
			LogMsg("%5d: Browser(%##s) already exists!",          c, qptr->q.qname.c);
		}
	if (l) LogMsg("%5d: Resolver(%##s) already exists!",          c, l->i.name.c);
	if (r) LogMsg("%5d: Registration(%##s) already exists!",      c, r->regs ? r->regs->srs.RR_SRV.resrec.name->c : NULL);
	return(e || b || l || r);
	}

#ifndef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

mDNSlocal void ClientDeathCallback(CFMachPortRef unusedport, void *voidmsg, CFIndex size, void *info)
	{
	KQueueLock(&mDNSStorage);
	mach_msg_header_t *msg = (mach_msg_header_t *)voidmsg;
	(void)unusedport; // Unused
	(void)size; // Unused
	(void)info; // Unused
	if (msg->msgh_id == MACH_NOTIFY_DEAD_NAME)
		{
		const mach_dead_name_notification_t *const deathMessage = (mach_dead_name_notification_t *)msg;
		AbortClient(deathMessage->not_port, NULL);

		/* Deallocate the send right that came in the dead name notification */
		mach_port_destroy(mach_task_self(), deathMessage->not_port);
		}
	KQueueUnlock(&mDNSStorage, "Mach AbortClient");
	}

#endif // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

mDNSlocal void EnableDeathNotificationForClient(mach_port_t ClientMachPort, void *m)
	{
#ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
	dispatch_source_t mach_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_MACH_SEND, ClientMachPort, 0, dispatch_get_main_queue());
	if (mach_source == mDNSNULL)
		{
		AbortClientWithLogMessage(ClientMachPort, "died/deallocated before we could enable death notification", "", m);
		return;
		}
	dispatch_source_set_event_handler(mach_source, ^{
		mach_port_destroy(mach_task_self(), ClientMachPort);
		});
	dispatch_resume(mach_source);
#else // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
	mach_port_t prev;
	kern_return_t r = mach_port_request_notification(mach_task_self(), ClientMachPort, MACH_NOTIFY_DEAD_NAME, 0,
													 client_death_port, MACH_MSG_TYPE_MAKE_SEND_ONCE, &prev);
	// If the port already died while we were thinking about it, then abort the operation right away
	if (r != KERN_SUCCESS)
		AbortClientWithLogMessage(ClientMachPort, "died/deallocated before we could enable death notification", "", m);
#endif // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
	}

//*************************************************************************************************************
// Domain Enumeration

mDNSlocal void DomainEnumFound(mDNS *const m, DNSQuestion *question, const ResourceRecord *const answer, QC_result AddRecord)
	{
	kern_return_t status;
	char buffer[MAX_ESCAPED_DOMAIN_NAME];
	DNSServiceDomainEnumerationReplyResultType rt;
	DNSServiceDomainEnumeration *x = (DNSServiceDomainEnumeration *)question->QuestionContext;
	(void)m; // Unused

	debugf("DomainEnumFound: %##s PTR %##s", answer->name->c, answer->rdata->u.name.c);
	if (answer->rrtype != kDNSType_PTR) return;
	if (!x) { debugf("DomainEnumFound: DNSServiceDomainEnumeration is NULL"); return; }

	if (AddRecord)
		{
		if (question == &x->dom) rt = DNSServiceDomainEnumerationReplyAddDomain;
		else                     rt = DNSServiceDomainEnumerationReplyAddDomainDefault;
		}
	else
		{
		if (question == &x->dom) rt = DNSServiceDomainEnumerationReplyRemoveDomain;
		else return;
		}

	LogOperation("%5d: DNSServiceDomainEnumeration(%##s) %##s %s",
		x->ClientMachPort, x->dom.qname.c, answer->rdata->u.name.c,
		!AddRecord ? "RemoveDomain" :
		question == &x->dom ? "AddDomain" : "AddDomainDefault");

	ConvertDomainNameToCString(&answer->rdata->u.name, buffer);
	status = DNSServiceDomainEnumerationReply_rpc(x->ClientMachPort, rt, buffer, 0, MDNS_MM_TIMEOUT);
	if (status == MACH_SEND_TIMED_OUT)
		AbortBlockedClient(x->ClientMachPort, "enumeration", x);
	}

mDNSexport kern_return_t provide_DNSServiceDomainEnumerationCreate_rpc(mach_port_t unusedserver, mach_port_t client,
	int regDom)
	{
	// Check client parameter
	(void)unusedserver; // Unused
	mStatus err = mStatus_NoError;
	const char *errormsg = "Unknown";
	if (client == (mach_port_t)-1)      { err = mStatus_Invalid; errormsg = "Client id -1 invalid";     goto fail; }
	if (CheckForExistingClient(client)) { err = mStatus_Invalid; errormsg = "Client id already in use"; goto fail; }

	mDNS_DomainType dt1 = regDom ? mDNS_DomainTypeRegistration        : mDNS_DomainTypeBrowse;
	mDNS_DomainType dt2 = regDom ? mDNS_DomainTypeRegistrationDefault : mDNS_DomainTypeBrowseDefault;

	// Allocate memory, and handle failure
	DNSServiceDomainEnumeration *x = mallocL("DNSServiceDomainEnumeration", sizeof(*x));
	if (!x) { err = mStatus_NoMemoryErr; errormsg = "No memory"; goto fail; }

	// Set up object, and link into list
	x->ClientMachPort = client;
	x->next = DNSServiceDomainEnumerationList;
	DNSServiceDomainEnumerationList = x;

	verbosedebugf("%5d: Enumerate %s Domains", client, regDom ? "Registration" : "Browsing");

	// Do the operation
	err           = mDNS_GetDomains(&mDNSStorage, &x->dom, dt1, NULL, mDNSInterface_LocalOnly, DomainEnumFound, x);
	if (!err) err = mDNS_GetDomains(&mDNSStorage, &x->def, dt2, NULL, mDNSInterface_LocalOnly, DomainEnumFound, x);
	if (err) { AbortClient(client, x); errormsg = "mDNS_GetDomains"; goto fail; }

	// Succeeded: Wrap up and return
	LogOperation("%5d: DNSServiceDomainEnumeration(%##s) START", client, x->dom.qname.c);
	EnableDeathNotificationForClient(client, x);
	return(mStatus_NoError);

fail:
	LogMsg("%5d: DNSServiceDomainEnumeration(%d) failed: %s (%d)", client, regDom, errormsg, err);
	return(err);
	}

//*************************************************************************************************************
// Browse for services

mDNSlocal void FoundInstance(mDNS *const m, DNSQuestion *question, const ResourceRecord *const answer, QC_result AddRecord)
	{
	(void)m;		// Unused

	if (answer->rrtype != kDNSType_PTR)
		{ LogMsg("FoundInstance: Should not be called with rrtype %d (not a PTR record)", answer->rrtype); return; }

	domainlabel name;
	domainname type, domain;
	if (!DeconstructServiceName(&answer->rdata->u.name, &name, &type, &domain))
		{
		LogMsg("FoundInstance: %##s PTR %##s received from network is not valid DNS-SD service pointer",
			answer->name->c, answer->rdata->u.name.c);
		return;
		}

	DNSServiceBrowserResult *x = mallocL("DNSServiceBrowserResult", sizeof(*x));
	if (!x) { LogMsg("FoundInstance: Failed to allocate memory for result %##s", answer->rdata->u.name.c); return; }

	verbosedebugf("FoundInstance: %s %##s", AddRecord ? "Add" : "Rmv", answer->rdata->u.name.c);
	AssignDomainName(&x->result, &answer->rdata->u.name);
	if (AddRecord)
		 x->resultType = DNSServiceBrowserReplyAddInstance;
	else x->resultType = DNSServiceBrowserReplyRemoveInstance;
	x->next = NULL;

	DNSServiceBrowser *browser = (DNSServiceBrowser *)question->QuestionContext;
	DNSServiceBrowserResult **p = &browser->results;
	while (*p) p = &(*p)->next;
	*p = x;

	LogOperation("%5d: DNSServiceBrowse(%##s, %s) RESULT %s %s",
		browser->ClientMachPort, question->qname.c, DNSTypeName(question->qtype), AddRecord ? "Add" : "Rmv", RRDisplayString(m, answer));
	}

mDNSlocal mStatus AddDomainToBrowser(DNSServiceBrowser *browser, const domainname *d)
	{
	mStatus err = mStatus_NoError;
	DNSServiceBrowserQuestion *ptr, *question = NULL;

	for (ptr = browser->qlist; ptr; ptr = ptr->next)
		{
		if (SameDomainName(&ptr->q.qname, d))
			{ debugf("Domain %##s already contained in browser", d->c); return mStatus_AlreadyRegistered; }
		}
	
	question = mallocL("DNSServiceBrowserQuestion", sizeof(DNSServiceBrowserQuestion));
	if (!question) { LogMsg("Error: malloc"); return mStatus_NoMemoryErr; }
	AssignDomainName(&question->domain, d);
	question->next = browser->qlist;
	LogOperation("%5d: DNSServiceBrowse(%##s%##s) START", browser->ClientMachPort, browser->type.c, d->c);
	err = mDNS_StartBrowse(&mDNSStorage, &question->q, &browser->type, d, mDNSInterface_Any, mDNSfalse, FoundInstance, browser);
	if (!err)
		browser->qlist = question;
	else
		{
		LogMsg("Error: AddDomainToBrowser: mDNS_StartBrowse %d", err);
		freeL("DNSServiceBrowserQuestion", question);
		}
	return err;
	}

mDNSexport void machserver_automatic_browse_domain_changed(const domainname *d, mDNSBool add)
	{
	DNSServiceBrowser *ptr;
	for (ptr = DNSServiceBrowserList; ptr; ptr = ptr->next)
		{
		if (ptr->DefaultDomain)
			{
			if (add)
				{
				mStatus err = AddDomainToBrowser(ptr, d);
				if (err && err != mStatus_AlreadyRegistered) LogMsg("Default browse in domain %##s for client %5d failed. Continuing", d, ptr->ClientMachPort);
				}
			else
				{
				DNSServiceBrowserQuestion **q = &ptr->qlist;
				while (*q)
					{
					if (SameDomainName(&(*q)->domain, d))
						{
						DNSServiceBrowserQuestion *rem = *q;
						*q = (*q)->next;
						mDNS_StopQueryWithRemoves(&mDNSStorage, &rem->q);
						freeL("DNSServiceBrowserQuestion", rem);
						return;
						}
					q = &(*q)->next;
					}
			    LogMsg("Requested removal of default domain %##s not in client %5d's list", d->c, ptr->ClientMachPort);
				}
			}
		}
	}

mDNSexport kern_return_t provide_DNSServiceBrowserCreate_rpc(mach_port_t unusedserver, mach_port_t client,
	DNSCString regtype, DNSCString domain)
	{
	// Check client parameter
	(void)unusedserver;		// Unused
	mStatus err = mStatus_NoError;
	const char *errormsg = "Unknown";

	if (client == (mach_port_t)-1)      { err = mStatus_Invalid; errormsg = "Client id -1 invalid";     goto fail; }
	if (CheckForExistingClient(client)) { err = mStatus_Invalid; errormsg = "Client id already in use"; goto fail; }

	// Check other parameters
	domainname t, d;
	t.c[0] = 0;
	mDNSs32 NumSubTypes = ChopSubTypes(regtype);	// Note: Modifies regtype string to remove trailing subtypes
	if (NumSubTypes < 0 || NumSubTypes > 1)               { errormsg = "Bad Service SubType"; goto badparam; }
	if (NumSubTypes == 1 && !AppendDNSNameString(&t, regtype + strlen(regtype) + 1))
	                                                      { errormsg = "Bad Service SubType"; goto badparam; }
	if (!regtype[0] || !AppendDNSNameString(&t, regtype)) { errormsg = "Illegal regtype";     goto badparam; }
	domainname temp;
	if (!MakeDomainNameFromDNSNameString(&temp, regtype)) { errormsg = "Illegal regtype";     goto badparam; }
	if (temp.c[0] > 15 && (!domain || domain[0] == 0)) domain = "local."; // For over-long service types, we only allow domain "local"

	// Allocate memory, and handle failure
	DNSServiceBrowser *x = mallocL("DNSServiceBrowser", sizeof(*x));
	if (!x) { err = mStatus_NoMemoryErr; errormsg = "No memory"; goto fail; }

	// Set up object, and link into list
	AssignDomainName(&x->type, &t);
	x->ClientMachPort = client;
	x->results = NULL;
	x->lastsuccess = 0;
	x->qlist = NULL;
	x->next = DNSServiceBrowserList;
	DNSServiceBrowserList = x;

	if (domain[0])
		{
		// Start browser for an explicit domain
		x->DefaultDomain = mDNSfalse;
		if (!MakeDomainNameFromDNSNameString(&d, domain)) { errormsg = "Illegal domain";  goto badparam; }
		err = AddDomainToBrowser(x, &d);
		if (err) { AbortClient(client, x); errormsg = "AddDomainToBrowser"; goto fail; }
		}
	else
		{
		DNameListElem *sdPtr;
		// Start browser on all domains
		x->DefaultDomain = mDNStrue;
		if (!AutoBrowseDomains) { AbortClient(client, x); errormsg = "GetSearchDomainList"; goto fail; }
		for (sdPtr = AutoBrowseDomains; sdPtr; sdPtr = sdPtr->next)
			{
			err = AddDomainToBrowser(x, &sdPtr->name);
			if (err)
				{
				// only terminally bail if .local fails
				if (!SameDomainName(&localdomain, &sdPtr->name))
					LogMsg("Default browse in domain %##s failed. Continuing", sdPtr->name.c);
				else { AbortClient(client, x); errormsg = "AddDomainToBrowser"; goto fail; }
				}
			}
		}
	
	// Succeeded: Wrap up and return
	EnableDeathNotificationForClient(client, x);
	return(mStatus_NoError);

	badparam:
	err = mStatus_BadParamErr;
fail:
	LogMsg("%5d: DNSServiceBrowse(\"%s\", \"%s\") failed: %s (%d)", client, regtype, domain, errormsg, err);
	return(err);
	}

//*************************************************************************************************************
// Resolve Service Info
	
mDNSlocal void FoundInstanceInfo(mDNS *const m, ServiceInfoQuery *query)
	{
	kern_return_t status;
	DNSServiceResolver *x = (DNSServiceResolver *)query->ServiceInfoQueryContext;
	NetworkInterfaceInfoOSX *ifx = IfindexToInterfaceInfoOSX(m, query->info->InterfaceID);
	if (query->info->InterfaceID == mDNSInterface_LocalOnly || query->info->InterfaceID == mDNSInterface_P2P) ifx = mDNSNULL;
	struct sockaddr_storage interface;
	struct sockaddr_storage address;
	char cstring[1024];
	int i, pstrlen = query->info->TXTinfo[0];
	(void)m;		// Unused

	//debugf("FoundInstanceInfo %.4a %.4a %##s", &query->info->InterfaceAddr, &query->info->ip, &query->info->name);

	if (query->info->TXTlen > sizeof(cstring)) return;

	mDNSPlatformMemZero(&interface, sizeof(interface));
	mDNSPlatformMemZero(&address,   sizeof(address));

	if (ifx && ifx->ifinfo.ip.type == mDNSAddrType_IPv4)
		{
		struct sockaddr_in *s = (struct sockaddr_in*)&interface;
		s->sin_len         = sizeof(*s);
		s->sin_family      = AF_INET;
		s->sin_port        = 0;
		s->sin_addr.s_addr = ifx->ifinfo.ip.ip.v4.NotAnInteger;
		}
	else if (ifx && ifx->ifinfo.ip.type == mDNSAddrType_IPv6)
		{
		struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&interface;
		sin6->sin6_len       = sizeof(*sin6);
		sin6->sin6_family    = AF_INET6;
		sin6->sin6_flowinfo  = 0;
		sin6->sin6_port      = 0;
		sin6->sin6_addr      = *(struct in6_addr*)&ifx->ifinfo.ip.ip.v6;
		sin6->sin6_scope_id  = ifx->scope_id;
		}

	if (query->info->ip.type == mDNSAddrType_IPv4)
		{
		struct sockaddr_in *s = (struct sockaddr_in*)&address;
		s->sin_len         = sizeof(*s);
		s->sin_family      = AF_INET;
		s->sin_port        = query->info->port.NotAnInteger;
		s->sin_addr.s_addr = query->info->ip.ip.v4.NotAnInteger;
		}
	else
		{
		struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&address;
		sin6->sin6_len           = sizeof(*sin6);
		sin6->sin6_family        = AF_INET6;
		sin6->sin6_port          = query->info->port.NotAnInteger;
		sin6->sin6_flowinfo      = 0;
		sin6->sin6_addr          = *(struct in6_addr*)&query->info->ip.ip.v6;
		sin6->sin6_scope_id      = ifx ? ifx->scope_id : 0;
		}

	// The OS X DNSServiceResolverResolve() API is defined using a C-string,
	// but the mDNS_StartResolveService() call actually returns a packed block of P-strings.
	// Hence we have to convert the P-string(s) to a C-string before returning the result to the client.
	// ASCII-1 characters are used in the C-string as boundary markers,
	// to indicate the boundaries between the original constituent P-strings.
	for (i=1; i<query->info->TXTlen; i++)
		{
		if (--pstrlen >= 0)
			cstring[i-1] = query->info->TXTinfo[i];
		else
			{
			cstring[i-1] = 1;
			pstrlen = query->info->TXTinfo[i];
			}
		}
	cstring[i-1] = 0;		// Put the terminating NULL on the end

	LogOperation("%5d: DNSServiceResolver(%##s) -> %#a:%u", x->ClientMachPort,
		x->i.name.c, &query->info->ip, mDNSVal16(query->info->port));
	status = DNSServiceResolverReply_rpc(x->ClientMachPort,
		(char*)&interface, (char*)&address, cstring, 0, MDNS_MM_TIMEOUT);
	if (status == MACH_SEND_TIMED_OUT)
		AbortBlockedClient(x->ClientMachPort, "resolve", x);
	}

mDNSexport kern_return_t provide_DNSServiceResolverResolve_rpc(mach_port_t unusedserver, mach_port_t client,
	DNSCString name, DNSCString regtype, DNSCString domain)
	{
	// Check client parameter
	(void)unusedserver;		// Unused
	mStatus err = mStatus_NoError;
	const char *errormsg = "Unknown";
	if (client == (mach_port_t)-1)      { err = mStatus_Invalid; errormsg = "Client id -1 invalid";     goto fail; }
	if (CheckForExistingClient(client)) { err = mStatus_Invalid; errormsg = "Client id already in use"; goto fail; }

	// Check other parameters
	domainlabel n;
	domainname t, d, srv;
	if (!name[0]    || !MakeDomainLabelFromLiteralString(&n, name))        { errormsg = "Bad Instance Name"; goto badparam; }
	if (!regtype[0] || !MakeDomainNameFromDNSNameString(&t, regtype))      { errormsg = "Bad Service Type";  goto badparam; }
	if (!domain[0]  || !MakeDomainNameFromDNSNameString(&d, domain))       { errormsg = "Bad Domain";        goto badparam; }
	if (!ConstructServiceName(&srv, &n, &t, &d))                           { errormsg = "Bad Name";          goto badparam; }

	// Allocate memory, and handle failure
	DNSServiceResolver *x = mallocL("DNSServiceResolver", sizeof(*x));
	if (!x) { err = mStatus_NoMemoryErr; errormsg = "No memory"; goto fail; }

	// Set up object, and link into list
	x->ClientMachPort = client;
	x->i.InterfaceID = mDNSInterface_Any;
	x->i.name = srv;
	x->ReportTime = NonZeroTime(mDNS_TimeNow(&mDNSStorage) + 130 * mDNSPlatformOneSecond);
	x->next = DNSServiceResolverList;
	DNSServiceResolverList = x;

	// Do the operation
	LogOperation("%5d: DNSServiceResolve(%##s) START", client, x->i.name.c);
	err = mDNS_StartResolveService(&mDNSStorage, &x->q, &x->i, FoundInstanceInfo, x);
	if (err) { AbortClient(client, x); errormsg = "mDNS_StartResolveService"; goto fail; }

	// Succeeded: Wrap up and return
	EnableDeathNotificationForClient(client, x);
	return(mStatus_NoError);

badparam:
	err = mStatus_BadParamErr;
fail:
	LogMsg("%5d: DNSServiceResolve(\"%s\", \"%s\", \"%s\") failed: %s (%d)", client, name, regtype, domain, errormsg, err);
	return(err);
	}

//*************************************************************************************************************
// Registration

mDNSexport void RecordUpdatedNiceLabel(mDNS *const m, mDNSs32 delay)
	{
	m->p->NotifyUser = NonZeroTime(m->timenow + delay);
	}

mDNSlocal void RegCallback(mDNS *const m, ServiceRecordSet *const srs, mStatus result)
	{
	ServiceInstance *si = (ServiceInstance*)srs->ServiceContext;

	if (result == mStatus_NoError)
		{
		kern_return_t status;
		LogOperation("%5d: DNSServiceRegistration(%##s, %u) Name Registered", si->ClientMachPort, srs->RR_SRV.resrec.name->c, SRS_PORT(srs));
		status = DNSServiceRegistrationReply_rpc(si->ClientMachPort, result, MDNS_MM_TIMEOUT);
		if (status == MACH_SEND_TIMED_OUT)
			AbortBlockedClient(si->ClientMachPort, "registration success", si);
		if (si->autoname && CountPeerRegistrations(m, srs) == 0)
			RecordUpdatedNiceLabel(m, 0);	// Successfully got new name, tell user immediately
		}

	else if (result == mStatus_NameConflict)
		{
		LogOperation("%5d: DNSServiceRegistration(%##s, %u) Name Conflict", si->ClientMachPort, srs->RR_SRV.resrec.name->c, SRS_PORT(srs));
		// Note: By the time we get the mStatus_NameConflict message, the service is already deregistered
		// and the memory is free, so we don't have to wait for an mStatus_MemFree message as well.
		if (si->autoname && CountPeerRegistrations(m, srs) == 0)
			{
			// On conflict for an autoname service, rename and reregister *all* autoname services
			IncrementLabelSuffix(&m->nicelabel, mDNStrue);
			mDNS_ConfigChanged(m);
			}
		else if (si->autoname)
			{
            mDNS_RenameAndReregisterService(m, srs, mDNSNULL);
            return;
			}
		else
			{
			// If we get a name conflict, we tell the client about it, and then they are expected to dispose
			// of their registration in the usual way (which we will catch via client death notification).
			// If the Mach queue is full, we forcibly abort the client immediately.
			kern_return_t status = DNSServiceRegistrationReply_rpc(si->ClientMachPort, result, MDNS_MM_TIMEOUT);
			if (status == MACH_SEND_TIMED_OUT)
				AbortBlockedClient(si->ClientMachPort, "registration conflict", NULL);
			}
		}

	else if (result == mStatus_MemFree)
		{
		if (si->renameonmemfree)	// We intentionally terminated registration so we could re-register with new name
			{
			debugf("RegCallback renaming %#s to %#s", si->name.c, m->nicelabel.c);
			si->renameonmemfree = mDNSfalse;
			si->name            = m->nicelabel;
			mDNS_RenameAndReregisterService(m, srs, &si->name);
			}
		else
			{
			// SANITY CHECK: make sure service instance is no longer in any ServiceRegistration's list
			DNSServiceRegistration *r;
			for (r = DNSServiceRegistrationList; r; r = r->next)
				{
				ServiceInstance **sp = &r->regs;
				while (*sp)
					{
					if (*sp == si) { LogMsg("RegCallback: %##s Still in list; removing", srs->RR_SRV.resrec.name->c); *sp = (*sp)->next; break; }
					sp = &(*sp)->next;
					}
			    }
			// END SANITY CHECK
			FreeServiceInstance(si);
			}
		}

	else if (result != mStatus_NATTraversal)
		LogMsg("%5d: DNSServiceRegistration(%##s, %u) Unknown Result %d", si->ClientMachPort, srs->RR_SRV.resrec.name->c, SRS_PORT(srs), result);
	}

mDNSlocal mStatus AddServiceInstance(DNSServiceRegistration *x, const domainname *domain)
	{
	mStatus err = 0;
	ServiceInstance *si = NULL;
	AuthRecord *SubTypes = NULL;

	for (si = x->regs; si; si = si->next)
		{
		if (SameDomainName(&si->domain, domain))
			{ LogMsg("Requested addition of domain %##s already in list", domain->c); return mStatus_AlreadyRegistered; }
		}
	
	SubTypes = AllocateSubTypes(x->NumSubTypes, x->regtype);
	if (x->NumSubTypes && !SubTypes) return mStatus_NoMemoryErr;
	
	si = mallocL("ServiceInstance", sizeof(*si) - sizeof(RDataBody) + x->rdsize);
	if (!si) return mStatus_NoMemoryErr;

	si->ClientMachPort  = x->ClientMachPort;
	si->renameonmemfree = mDNSfalse;
	si->autoname        = x->autoname;
	si->name            = x->autoname ? mDNSStorage.nicelabel : x->name;
	si->domain          = *domain;

	err = mDNS_RegisterService(&mDNSStorage, &si->srs, &si->name, &x->type, domain, NULL,
		x->port, x->txtinfo, x->txt_len, SubTypes, x->NumSubTypes, mDNSInterface_Any, RegCallback, si, 0);
	if (!err)
		{
		si->next = x->regs;
		x->regs = si;
		}
	else
		{
		LogMsg("Error %d for registration of service in domain %##s", err, domain->c);
		freeL("ServiceInstance", si);
		}
	return err;
	}

mDNSexport void machserver_automatic_registration_domain_changed(const domainname *d, mDNSBool add)
	{
	DNSServiceRegistration *reg;

	for (reg = DNSServiceRegistrationList; reg; reg = reg->next)
		{
		if (reg->DefaultDomain)
			{
			if (add)
				AddServiceInstance(reg, d);
			else
				{
				ServiceInstance **si = &reg->regs;
				while (*si)
					{
					if (SameDomainName(&(*si)->domain, d))
						{
						ServiceInstance *s = *si;
						*si = (*si)->next;
						if (mDNS_DeregisterService(&mDNSStorage, &s->srs)) FreeServiceInstance(s);  // only free memory synchronously on error
						break;
						}
					si = &(*si)->next;
					}
				if (!si) debugf("Requested removal of default domain %##s not in client %5d's list", d, reg->ClientMachPort); // normal if registration failed
				}
			}
		}
	}

mDNSexport kern_return_t provide_DNSServiceRegistrationCreate_rpc(mach_port_t unusedserver, mach_port_t client,
	DNSCString name, DNSCString regtype, DNSCString domain, IPPort IpPort, DNSCString txtRecord)
	{
	(void)unusedserver;		// Unused
	mStatus err = mStatus_NoError;
	const char *errormsg = "Unknown";

	// older versions of this code passed the port via mach IPC as an int.
	// we continue to pass it as 4 bytes to maintain binary compatibility,
	// but now ensure that the network byte order is preserved by using a struct
	mDNSIPPort port;
	port.b[0] = IpPort.bytes[2];
	port.b[1] = IpPort.bytes[3];

	if (client == (mach_port_t)-1)      { err = mStatus_Invalid; errormsg = "Client id -1 invalid";     goto fail; }
	if (CheckForExistingClient(client)) { err = mStatus_Invalid; errormsg = "Client id already in use"; goto fail; }

    // Check for sub-types after the service type
	size_t reglen = strlen(regtype) + 1;
	if (reglen > MAX_ESCAPED_DOMAIN_NAME) { errormsg = "reglen too long"; goto badparam; }
	mDNSs32 NumSubTypes = ChopSubTypes(regtype);	// Note: Modifies regtype string to remove trailing subtypes
	if (NumSubTypes < 0) { errormsg = "Bad Service SubType"; goto badparam; }

	// Check other parameters
	domainlabel n;
	domainname t, d;
	domainname srv;
	if (!name[0]) n = mDNSStorage.nicelabel;
	else if (!MakeDomainLabelFromLiteralString(&n, name))                  { errormsg = "Bad Instance Name"; goto badparam; }
	if (!regtype[0] || !MakeDomainNameFromDNSNameString(&t, regtype))      { errormsg = "Bad Service Type";  goto badparam; }
	if (!MakeDomainNameFromDNSNameString(&d, *domain ? domain : "local.")) { errormsg = "Bad Domain";        goto badparam; }
	if (!ConstructServiceName(&srv, &n, &t, &d))                           { errormsg = "Bad Name";          goto badparam; }

	unsigned char txtinfo[1024] = "";
	unsigned int data_len = 0;
	unsigned int size = sizeof(RDataBody);
	unsigned char *pstring = &txtinfo[data_len];
	char *ptr = txtRecord;

	// The OS X DNSServiceRegistrationCreate() API is defined using a C-string,
	// but the mDNS_RegisterService() call actually requires a packed block of P-strings.
	// Hence we have to convert the C-string to a P-string.
	// ASCII-1 characters are allowed in the C-string as boundary markers,
	// so that a single C-string can be used to represent one or more P-strings.
	while (*ptr)
		{
		if (++data_len >= sizeof(txtinfo)) { errormsg = "TXT record too long"; goto badtxt; }
		if (*ptr == 1)		// If this is our boundary marker, start a new P-string
			{
			pstring = &txtinfo[data_len];
			pstring[0] = 0;
			ptr++;
			}
		else
			{
			if (pstring[0] == 255) { errormsg = "TXT record invalid (component longer than 255)"; goto badtxt; }
			pstring[++pstring[0]] = *ptr++;
			}
		}

	data_len++;
	if (size < data_len)
		size = data_len;

	// Some clients use mDNS for lightweight copy protection, registering a pseudo-service with
	// a port number of zero. When two instances of the protected client are allowed to run on one
	// machine, we don't want to see misleading "Bogus client" messages in syslog and the console.
	if (!mDNSIPPortIsZero(port))
		{
		int count = CountExistingRegistrations(&srv, port);
		if (count)
			LogMsg("%5d: Client application registered %d identical instances of service %##s port %u.",
				   client, count+1, srv.c, mDNSVal16(port));
		}
	
	// Allocate memory, and handle failure
	DNSServiceRegistration *x = mallocL("DNSServiceRegistration", sizeof(*x));
	if (!x) { err = mStatus_NoMemoryErr; errormsg = "No memory"; goto fail; }
	mDNSPlatformMemZero(x, sizeof(*x));

	// Set up object, and link into list
	x->ClientMachPort = client;
	x->DefaultDomain = !domain[0];
	x->autoname = (!name[0]);
	x->rdsize = size;
	x->NumSubTypes = NumSubTypes;
	memcpy(x->regtype, regtype, reglen);
	x->name = n;
	x->type = t;
	x->port = port;
	memcpy(x->txtinfo, txtinfo, 1024);
	x->txt_len = data_len;
	x->NextRef = 0;
	x->regs = NULL;
	
	x->next = DNSServiceRegistrationList;
	DNSServiceRegistrationList = x;

	LogOperation("%5d: DNSServiceRegistration(\"%s\", \"%s\", \"%s\", %u) START",
		x->ClientMachPort, name, regtype, domain, mDNSVal16(port));

   	err = AddServiceInstance(x, &d);
	if (err) { AbortClient(client, x); errormsg = "mDNS_RegisterService"; goto fail; }  // bail if .local (or explicit domain) fails

	if (x->DefaultDomain)
		{
		DNameListElem *p;
		for (p = AutoRegistrationDomains; p; p = p->next)
			AddServiceInstance(x, &p->name);
		}

	// Succeeded: Wrap up and return
	EnableDeathNotificationForClient(client, x);
	return(mStatus_NoError);

badtxt:
	LogMsg("%5d: TXT record: %.100s...", client, txtRecord);
badparam:
	err = mStatus_BadParamErr;
fail:
	LogMsg("%5d: DNSServiceRegister(\"%s\", \"%s\", \"%s\", %d) failed: %s (%d)",
		   client, name, regtype, domain, mDNSVal16(port), errormsg, err);
	return(err);
	}

mDNSlocal void mDNSPreferencesSetNames(mDNS *const m, int key, domainlabel *old, domainlabel *new)
	{
	domainlabel *prevold, *prevnew;
	switch (key)
		{
		case kmDNSComputerName:
		case kmDNSLocalHostName:
			if (key == kmDNSComputerName)
				{
				prevold = &m->p->prevoldnicelabel;
				prevnew = &m->p->prevnewnicelabel;
				}
			else
				{
				prevold = &m->p->prevoldhostlabel;
				prevnew = &m->p->prevnewhostlabel;
				}
			// There are a few cases where we need to invoke the helper.
			//
			// 1. If the "old" label and "new" label are not same, it means there is a conflict. We need
			//    to invoke the helper so that it pops up a dialogue to inform the user about the
			//    conflict
			//
			// 2. If the "old" label and "new" label are same, it means the user has set the host/nice label
			//    through the preferences pane. We may have to inform the helper as it may have popped up
			//    a dialogue previously (due to a conflict) and it needs to suppress it now. We can avoid invoking
			//    the helper in this case if the previous values (old and new) that we told helper last time
			//    are same. If the previous old and new values are same, helper does not care.
			//
			// Note: "new" can be NULL when we have repeated conflicts and we are asking helper to give up. "old"
			// is not called with NULL today, but this makes it future proof.
			if (!old || !new || !SameDomainLabelCS(old->c, new->c) || 
			    !SameDomainLabelCS(old->c, prevold->c) ||
			    !SameDomainLabelCS(new->c, prevnew->c))
				{
				if (old)
					*prevold = *old;
				else
					prevold->c[0] = 0;
				if (new)
					*prevnew = *new;
				else
					prevnew->c[0] = 0;
				mDNSPreferencesSetName(key, old, new);
				}
			else 
				{
				LogInfo("mDNSPreferencesSetNames not invoking helper %s %#s, %s %#s, old %#s, new %#s",
						(key == kmDNSComputerName ? "prevoldnicelabel" : "prevoldhostlabel"), prevold->c,
						(key == kmDNSComputerName ? "prevnewnicelabel" : "prevnewhostlabel"), prevnew->c,
						old->c, new->c);
				}
			break;
		default:
			LogMsg("mDNSPreferencesSetNames: unrecognized key: %d", key);
			return;
		}
	}

mDNSlocal void mDNS_StatusCallback(mDNS *const m, mStatus result)
	{
	(void)m; // Unused
	if (result == mStatus_NoError)
		{
		if (!SameDomainLabelCS(m->p->userhostlabel.c, m->hostlabel.c))
			LogInfo("Local Hostname changed from \"%#s.local\" to \"%#s.local\"", m->p->userhostlabel.c, m->hostlabel.c);
		// One second pause in case we get a Computer Name update too -- don't want to alert the user twice
		RecordUpdatedNiceLabel(m, mDNSPlatformOneSecond);
		}
	else if (result == mStatus_NameConflict)
		{
		LogInfo("Local Hostname conflict for \"%#s.local\"", m->hostlabel.c);
		if (!m->p->HostNameConflict) m->p->HostNameConflict = NonZeroTime(m->timenow);
		else if (m->timenow - m->p->HostNameConflict > 60 * mDNSPlatformOneSecond)
			{
			// Tell the helper we've given up
			mDNSPreferencesSetNames(m, kmDNSLocalHostName, &m->p->userhostlabel, NULL);
			}
		}
	else if (result == mStatus_GrowCache)
		{
		// Allocate another chunk of cache storage
		CacheEntity *storage = mallocL("mStatus_GrowCache", sizeof(CacheEntity) * RR_CACHE_SIZE);
		//LogInfo("GrowCache %d * %d = %d", sizeof(CacheEntity), RR_CACHE_SIZE, sizeof(CacheEntity) * RR_CACHE_SIZE);
		if (storage) mDNS_GrowCache(m, storage, RR_CACHE_SIZE);
		}
	else if (result == mStatus_ConfigChanged)
		{
		// Tell the helper we've seen a change in the labels.  It will dismiss the name conflict alert if needed.
		mDNSPreferencesSetNames(m, kmDNSComputerName, &m->p->usernicelabel, &m->nicelabel);
		mDNSPreferencesSetNames(m, kmDNSLocalHostName, &m->p->userhostlabel, &m->hostlabel);

		// First we check our list of old Mach-based registered services, to see if any need to be updated to a new name
		DNSServiceRegistration *r;
		for (r = DNSServiceRegistrationList; r; r=r->next)
			if (r->autoname)
				{
				ServiceInstance *si;
				for (si = r->regs; si; si = si->next)
					{
					if (!SameDomainLabelCS(si->name.c, m->nicelabel.c))
						{
						debugf("NetworkChanged renaming %##s to %#s", si->srs.RR_SRV.resrec.name->c, m->nicelabel.c);
						si->renameonmemfree = mDNStrue;
						if (mDNS_DeregisterService_drt(m, &si->srs, mDNS_Dereg_rapid))
							RegCallback(m, &si->srs, mStatus_MemFree);	// If service deregistered already, we can re-register immediately
						}
					}
				}

		// Then we call into the UDS daemon code, to let it do the same
		udsserver_handle_configchange(m);
		}
	}

//*************************************************************************************************************
// Add / Update / Remove records from existing Registration

mDNSexport kern_return_t provide_DNSServiceRegistrationAddRecord_rpc(mach_port_t unusedserver, mach_port_t client,
	int type, const char *data, mach_msg_type_number_t data_len, uint32_t ttl, natural_t *reference)
	{
	// Check client parameter
	uint32_t id;
	mStatus err = mStatus_NoError;
	const char *errormsg = "Unknown";
	DNSServiceRegistration *x = DNSServiceRegistrationList;
	if (client == (mach_port_t)-1) { err = mStatus_Invalid;         errormsg = "Client id -1 invalid"; goto fail; }
	ServiceInstance *si;
	size_t size;
	(void)unusedserver;		// Unused
	while (x && x->ClientMachPort != client) x = x->next;
	if (!x)                        { err = mStatus_BadReferenceErr; errormsg = "No such client";       goto fail; }

	// Check other parameters
	if (data_len > 8192) { err = mStatus_BadParamErr; errormsg = "data_len > 8K"; goto fail; }
	if (data_len > sizeof(RDataBody)) size = data_len;
	else size = sizeof(RDataBody);
	
	id = x->NextRef++;
	*reference = (natural_t)id;
	for (si = x->regs; si; si = si->next)
		{
		// Allocate memory, and handle failure
		ExtraResourceRecord *extra = mallocL("ExtraResourceRecord", sizeof(*extra) - sizeof(RDataBody) + size);
		if (!extra) { err = mStatus_NoMemoryErr; errormsg = "No memory"; goto fail; }
		
		// Fill in type, length, and data of new record
		extra->r.resrec.rrtype = type;
		extra->r.rdatastorage.MaxRDLength = size;
		extra->r.resrec.rdlength          = data_len;
		memcpy(&extra->r.rdatastorage.u.data, data, data_len);

		// Do the operation
		LogOperation("%5d: DNSServiceRegistrationAddRecord(%##s, type %d, length %d) REF %p",
					 client, si->srs.RR_SRV.resrec.name->c, type, data_len, extra);
		err = mDNS_AddRecordToService(&mDNSStorage, &si->srs, extra, &extra->r.rdatastorage, ttl, 0);

		if (err)
			{
			freeL("Extra Resource Record", extra);
			errormsg = "mDNS_AddRecordToService";
			goto fail;
			}

		extra->ClientID = id;
		}

	return mStatus_NoError;

fail:
	LogMsg("%5d: DNSServiceRegistrationAddRecord(%##s, type %d, length %d) failed: %s (%d)", client, x ? x->name.c : (mDNSu8*)"\x8""«NULL»", type, data_len, errormsg, err);
	return mStatus_UnknownErr;
	}

mDNSlocal void UpdateCallback(mDNS *const m, AuthRecord *const rr, RData *OldRData, mDNSu16 OldRDLen)
	{
	(void)m;		// Unused
	(void)OldRDLen;	// Unused
	if (OldRData != &rr->rdatastorage)
		freeL("Old RData", OldRData);
	}

mDNSlocal mStatus UpdateRecord(ServiceRecordSet *srs, mach_port_t client, AuthRecord *rr, const char *data, mach_msg_type_number_t data_len, uint32_t ttl)
	{
    // Check client parameter
	mStatus err = mStatus_NoError;
	const char *errormsg = "Unknown";
	const domainname *name = (const domainname *)"";

	name = srs->RR_SRV.resrec.name;

	unsigned int size = sizeof(RDataBody);
    if (size < data_len)
		size = data_len;

	// Allocate memory, and handle failure
	RData *newrdata = mallocL("RData", sizeof(*newrdata) - sizeof(RDataBody) + size);
	if (!newrdata) { err = mStatus_NoMemoryErr; errormsg = "No memory"; goto fail; }

	// Fill in new length, and data
	newrdata->MaxRDLength = size;
	memcpy(&newrdata->u, data, data_len);
	
	// BIND named (name daemon) doesn't allow TXT records with zero-length rdata. This is strictly speaking correct,
	// since RFC 1035 specifies a TXT record as "One or more <character-string>s", not "Zero or more <character-string>s".
	// Since some legacy apps try to create zero-length TXT records, we'll silently correct it here.
	if (rr->resrec.rrtype == kDNSType_TXT && data_len == 0) { data_len = 1; newrdata->u.txt.c[0] = 0; }

	// Do the operation
	LogOperation("%5d: DNSServiceRegistrationUpdateRecord(%##s, new length %d)",
		client, srs->RR_SRV.resrec.name->c, data_len);

	err = mDNS_Update(&mDNSStorage, rr, ttl, data_len, newrdata, UpdateCallback);
	if (err)
		{
		errormsg = "mDNS_Update";
		freeL("RData", newrdata);
		return err;
		}
	return(mStatus_NoError);

fail:
	LogMsg("%5d: DNSServiceRegistrationUpdateRecord(%##s, %d) failed: %s (%d)", client, name->c, data_len, errormsg, err);
	return(err);
	}

mDNSexport kern_return_t provide_DNSServiceRegistrationUpdateRecord_rpc(mach_port_t unusedserver, mach_port_t client,
		natural_t reference, const char *data, mach_msg_type_number_t data_len, uint32_t ttl)
   	{
    // Check client parameter
	mStatus err = mStatus_NoError;
	const char *errormsg = "Unknown";
	const domainname *name = (const domainname *)"";
	ServiceInstance *si;

	(void)unusedserver; // unused
    if (client == (mach_port_t)-1) { err = mStatus_Invalid;         errormsg = "Client id -1 invalid"; goto fail; }
	DNSServiceRegistration *x = DNSServiceRegistrationList;
	while (x && x->ClientMachPort != client) x = x->next;
	if (!x)                        { err = mStatus_BadReferenceErr; errormsg = "No such client";       goto fail; }

	// Check other parameters
	if (data_len > 8192) { err = mStatus_BadParamErr; errormsg = "data_len > 8K"; goto fail; }

	for (si = x->regs; si; si = si->next)
		{
		AuthRecord *r = NULL;

		// Find the record we're updating. NULL reference means update the primary TXT record
		if (!reference) r = &si->srs.RR_TXT;
		else
			{
			ExtraResourceRecord *ptr;
			for (ptr = si->srs.Extras; ptr; ptr = ptr->next)
				{
				if ((natural_t)ptr->ClientID == reference)
					{ r = &ptr->r; break; }
				}
			if (!r) { err = mStatus_BadReferenceErr; errormsg = "No such record"; goto fail; }
			}
		err = UpdateRecord(&si->srs, client, r, data, data_len, ttl);
		if (err) goto fail;  //!!!KRS this will cause failures for non-local defaults!
		}
					
	return mStatus_NoError;

fail:
	LogMsg("%5d: DNSServiceRegistrationUpdateRecord(%##s, %X, %d) failed: %s (%d)", client, name->c, reference, data_len, errormsg, err);
	return(err);
	}

mDNSlocal mStatus RemoveRecord(ServiceRecordSet *srs, ExtraResourceRecord *extra, mach_port_t client)
	{
	const domainname *const name = srs->RR_SRV.resrec.name;
	mStatus err = mStatus_NoError;

	// Do the operation
	LogOperation("%5d: DNSServiceRegistrationRemoveRecord(%##s)", client, srs->RR_SRV.resrec.name->c);

	err = mDNS_RemoveRecordFromService(&mDNSStorage, srs, extra, FreeExtraRR, extra);
	if (err) LogMsg("%5d: DNSServiceRegistrationRemoveRecord (%##s) failed: %d", client, name->c, err);
	
	return err;
	}

mDNSexport kern_return_t provide_DNSServiceRegistrationRemoveRecord_rpc(mach_port_t unusedserver, mach_port_t client,
	natural_t reference)
	{
	// Check client parameter
	(void)unusedserver;		// Unused
	mStatus err = mStatus_NoError;
	const char *errormsg = "Unknown";
	if (client == (mach_port_t)-1) { err = mStatus_Invalid;         errormsg = "Client id -1 invalid"; goto fail; }
	DNSServiceRegistration *x = DNSServiceRegistrationList;
	ServiceInstance *si;

	while (x && x->ClientMachPort != client) x = x->next;
	if (!x)                        { err = mStatus_BadReferenceErr; errormsg = "No such client";       goto fail; }

	for (si = x->regs; si; si = si->next)
		{
		ExtraResourceRecord *e;
		for (e = si->srs.Extras; e; e = e->next)
			{
			if ((natural_t)e->ClientID == reference)
				{
				err = RemoveRecord(&si->srs, e, client);
				break;
				}
			}
		if (!e) { err = mStatus_BadReferenceErr; errormsg = "No such reference"; goto fail; }
		}

	return mStatus_NoError;

fail:
	LogMsg("%5d: DNSServiceRegistrationRemoveRecord(%X) failed: %s (%d)", client, reference, errormsg, err);
	return(err);
	}

//*************************************************************************************************************
#if COMPILER_LIKES_PRAGMA_MARK
#pragma mark -
#pragma mark - Startup, shutdown, and supporting code
#endif

mDNSlocal void DNSserverCallback(CFMachPortRef port, void *msg, CFIndex size, void *info)
	{
	mig_reply_error_t *request = msg;
	mig_reply_error_t *reply;
	mach_msg_return_t mr;
	int               options;
	(void)port;		// Unused
	(void)size;		// Unused
	(void)info;		// Unused

	KQueueLock(&mDNSStorage);
	
	/* allocate a reply buffer */
	reply = CFAllocatorAllocate(NULL, provide_DNSServiceDiscoveryRequest_subsystem.maxsize, 0);

	/* call the MiG server routine */
	(void) DNSServiceDiscoveryRequest_server(&request->Head, &reply->Head);

	if (!(reply->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX) && (reply->RetCode != KERN_SUCCESS))
		{
        if (reply->RetCode == MIG_NO_REPLY)
			{
            /*
             * This return code is a little tricky -- it appears that the
             * demux routine found an error of some sort, but since that
             * error would not normally get returned either to the local
             * user or the remote one, we pretend it's ok.
             */
            CFAllocatorDeallocate(NULL, reply);
            goto done;
			}

        /*
         * destroy any out-of-line data in the request buffer but don't destroy
         * the reply port right (since we need that to send an error message).
         */
        request->Head.msgh_remote_port = MACH_PORT_NULL;
        mach_msg_destroy(&request->Head);
		}

    if (reply->Head.msgh_remote_port == MACH_PORT_NULL)
		{
        /* no reply port, so destroy the reply */
        if (reply->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX)
            mach_msg_destroy(&reply->Head);
        CFAllocatorDeallocate(NULL, reply);
        goto done;
		}

    /*
     * send reply.
     *
     * We don't want to block indefinitely because the client
     * isn't receiving messages from the reply port.
     * If we have a send-once right for the reply port, then
     * this isn't a concern because the send won't block.
     * If we have a send right, we need to use MACH_SEND_TIMEOUT.
     * To avoid falling off the kernel's fast RPC path unnecessarily,
     * we only supply MACH_SEND_TIMEOUT when absolutely necessary.
     */

    options = MACH_SEND_MSG;
    if (MACH_MSGH_BITS_REMOTE(reply->Head.msgh_bits) == MACH_MSG_TYPE_MOVE_SEND_ONCE)
        options |= MACH_SEND_TIMEOUT;

    mr = mach_msg(&reply->Head,		/* msg */
		      options,			/* option */
		      reply->Head.msgh_size,	/* send_size */
		      0,			/* rcv_size */
		      MACH_PORT_NULL,		/* rcv_name */
		      MACH_MSG_TIMEOUT_NONE,	/* timeout */
		      MACH_PORT_NULL);		/* notify */

    /* Has a message error occurred? */
    switch (mr)
		{
        case MACH_SEND_INVALID_DEST:
        case MACH_SEND_TIMED_OUT:
            /* the reply can't be delivered, so destroy it */
            mach_msg_destroy(&reply->Head);
            break;

        default :
            /* Includes success case. */
            break;
		}

    CFAllocatorDeallocate(NULL, reply);
	
done:
	KQueueUnlock(&mDNSStorage, "Mach client event");
	}

mDNSlocal kern_return_t registerBootstrapService()
	{
	kern_return_t status;
	mach_port_t service_send_port, service_rcv_port;

	debugf("Registering Bootstrap Service");

	/*
	 * See if our service name is already registered and if we have privilege to check in.
	 */
	status = bootstrap_check_in(bootstrap_port, (char*)kmDNSBootstrapName, &service_rcv_port);
	if (status == KERN_SUCCESS)
		{
		/*
		 * If so, we must be a followup instance of an already defined server.  In that case,
		 * the bootstrap port we inherited from our parent is the server's privilege port, so set
		 * that in case we have to unregister later (which requires the privilege port).
		 */
		server_priv_port = bootstrap_port;
		restarting_via_mach_init = TRUE;
		}
	else if (status == BOOTSTRAP_UNKNOWN_SERVICE)
		{
		status = bootstrap_create_server(bootstrap_port, "/usr/sbin/mDNSResponder", getuid(),
			FALSE /* relaunch immediately, not on demand */, &server_priv_port);
		if (status != KERN_SUCCESS) return status;

		status = bootstrap_create_service(server_priv_port, (char*)kmDNSBootstrapName, &service_send_port);
		if (status != KERN_SUCCESS)
			{
			mach_port_deallocate(mach_task_self(), server_priv_port);
			return status;
			}

		status = bootstrap_check_in(server_priv_port, (char*)kmDNSBootstrapName, &service_rcv_port);
		if (status != KERN_SUCCESS)
			{
			mach_port_deallocate(mach_task_self(), server_priv_port);
			mach_port_deallocate(mach_task_self(), service_send_port);
			return status;
			}
		assert(service_send_port == service_rcv_port);
		}

	/*
	 * We have no intention of responding to requests on the service port.  We are not otherwise
	 * a Mach port-based service.  We are just using this mechanism for relaunch facilities.
	 * So, we can dispose of all the rights we have for the service port.  We don't destroy the
	 * send right for the server's privileged bootstrap port - in case we have to unregister later.
	 */
	mach_port_destroy(mach_task_self(), service_rcv_port);
	return status;
	}

mDNSlocal kern_return_t destroyBootstrapService()
	{
	debugf("Destroying Bootstrap Service");
	return bootstrap_register(server_priv_port, (char*)kmDNSBootstrapName, MACH_PORT_NULL);
	}

mDNSlocal void ExitCallback(int sig)
	{
	(void)sig; // Unused
	LogMsg("%s stopping", mDNSResponderVersionString);

	debugf("ExitCallback");
	if (!mDNS_DebugMode && !started_via_launchdaemon)
		destroyBootstrapService();

	debugf("ExitCallback: Aborting MIG clients");
	while (DNSServiceDomainEnumerationList)
		AbortClient(DNSServiceDomainEnumerationList->ClientMachPort, DNSServiceDomainEnumerationList);
	while (DNSServiceBrowserList)
		AbortClient(DNSServiceBrowserList          ->ClientMachPort, DNSServiceBrowserList);
	while (DNSServiceResolverList)
		AbortClient(DNSServiceResolverList         ->ClientMachPort, DNSServiceResolverList);
	while (DNSServiceRegistrationList)
		AbortClient(DNSServiceRegistrationList     ->ClientMachPort, DNSServiceRegistrationList);

	if (udsserver_exit() < 0) LogMsg("ExitCallback: udsserver_exit failed");

	debugf("ExitCallback: mDNS_StartExit");
	mDNS_StartExit(&mDNSStorage);
	}

#ifndef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

// Send a mach_msg to ourselves (since that is signal safe) telling us to cleanup and exit
mDNSlocal void HandleSIG(int sig)
	{
	kern_return_t status;
	mach_msg_header_t header;

	// WARNING: can't call syslog or fprintf from signal handler
	header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_MAKE_SEND, 0);
	header.msgh_remote_port = signal_port;
	header.msgh_local_port = MACH_PORT_NULL;
	header.msgh_size = sizeof(header);
	header.msgh_id = sig;

	status = mach_msg(&header, MACH_SEND_MSG | MACH_SEND_TIMEOUT, header.msgh_size,
		0, MACH_PORT_NULL, 0, MACH_PORT_NULL);

	if (status != MACH_MSG_SUCCESS)
		{
		if (status == MACH_SEND_TIMED_OUT) mach_msg_destroy(&header);
		if (sig == SIGTERM || sig == SIGINT) exit(-1);
		}
	}

#endif // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

mDNSlocal void INFOCallback(void)
	{
	mDNSs32 utc = mDNSPlatformUTC();
	DNSServiceDomainEnumeration *e;
	DNSServiceBrowser           *b;
	DNSServiceResolver          *l;
	DNSServiceRegistration      *r;
	NetworkInterfaceInfoOSX     *i;
	DNSServer *s;
	McastResolver *mr;

	LogMsg("---- BEGIN STATE LOG ---- %s %s %d", mDNSResponderVersionString, OSXVers ? "OSXVers" : "iOSVers", OSXVers ? OSXVers : iOSVers);
	
	udsserver_info(&mDNSStorage);

	LogMsgNoIdent("--------- Mach Clients ---------");
	if (!DNSServiceDomainEnumerationList && !DNSServiceBrowserList && !DNSServiceResolverList && !DNSServiceRegistrationList)
		LogMsgNoIdent("<None>");
	else
		{
		for (e = DNSServiceDomainEnumerationList; e; e=e->next)
			LogMsgNoIdent("%5d: Mach DomainEnumeration   %##s", e->ClientMachPort, e->dom.qname.c);
	
		for (b = DNSServiceBrowserList; b; b=b->next)
			{
			DNSServiceBrowserQuestion *qptr;
			for (qptr = b->qlist; qptr; qptr = qptr->next)
				LogMsgNoIdent("%5d: Mach ServiceBrowse       %##s", b->ClientMachPort, qptr->q.qname.c);
			}

		for (l = DNSServiceResolverList; l; l=l->next)
			LogMsgNoIdent("%5d: Mach ServiceResolve      %##s", l->ClientMachPort, l->i.name.c);
	
		for (r = DNSServiceRegistrationList; r; r=r->next)
			{
			ServiceInstance *si;
			for (si = r->regs; si; si = si->next)
				LogMsgNoIdent("%5d: Mach ServiceInstance     %##s %u", si->ClientMachPort, si->srs.RR_SRV.resrec.name->c, mDNSVal16(si->srs.RR_SRV.resrec.rdata->u.srv.port));
			}
		}

	LogMsgNoIdent("----- KQSocketEventSources -----");
	if (!gEventSources) LogMsgNoIdent("<None>");
	else
		{
		KQSocketEventSource *k;
		for (k = gEventSources; k; k=k->next)
			{
			LogMsgNoIdent("%3d %s", k->fd, k->kqs.KQtask);
			usleep((mDNSStorage.KnownBugs & mDNS_KnownBug_LossySyslog) ? 3333 : 1000);
			}
		}

	LogMsgNoIdent("------ Network Interfaces ------");
	if (!mDNSStorage.p->InterfaceList) LogMsgNoIdent("<None>");
	else
		{
		for (i = mDNSStorage.p->InterfaceList; i; i = i->next)
			{
			// Allow six characters for interface name, for names like "vmnet8"
			if (!i->Exists)
				LogMsgNoIdent("%p %2ld, Registered %p,  %s %-6s(%lu) %.6a %.6a %#-14a dormant for %d seconds",
					i, i->ifinfo.InterfaceID, i->Registered,
					i->sa_family == AF_INET ? "v4" : i->sa_family == AF_INET6 ? "v6" : "??", i->ifinfo.ifname, i->scope_id, &i->ifinfo.MAC, &i->BSSID,
					&i->ifinfo.ip, utc - i->LastSeen);
			else
				{
				const CacheRecord *sps[3];
				FindSPSInCache(&mDNSStorage, &i->ifinfo.NetWakeBrowse, sps);
				LogMsgNoIdent("%p %2ld, Registered %p,  %s %-6s(%lu) %.6a %.6a %s %s %-15.4a %s %s %s %s %#a",
					i, i->ifinfo.InterfaceID, i->Registered,
					i->sa_family == AF_INET ? "v4" : i->sa_family == AF_INET6 ? "v6" : "??", i->ifinfo.ifname, i->scope_id, &i->ifinfo.MAC, &i->BSSID,
					i->ifinfo.InterfaceActive ? "Active" : "      ",
					i->ifinfo.IPv4Available ? "v4" : "  ",
					i->ifinfo.IPv4Available ? (mDNSv4Addr*)&i->ifa_v4addr : &zerov4Addr,
					i->ifinfo.IPv6Available ? "v6" : "  ",
					i->ifinfo.Advertise ? "⊙" : " ",
					i->ifinfo.McastTxRx ? "⇆" : " ",
					!(i->ifinfo.InterfaceActive && i->ifinfo.NetWake) ? " " : !sps[0] ? "☼" : "☀",
					&i->ifinfo.ip);

				if (sps[0]) LogMsgNoIdent("  %13d %#s", SPSMetric(sps[0]->resrec.rdata->u.name.c), sps[0]->resrec.rdata->u.name.c);
				if (sps[1]) LogMsgNoIdent("  %13d %#s", SPSMetric(sps[1]->resrec.rdata->u.name.c), sps[1]->resrec.rdata->u.name.c);
				if (sps[2]) LogMsgNoIdent("  %13d %#s", SPSMetric(sps[2]->resrec.rdata->u.name.c), sps[2]->resrec.rdata->u.name.c);
				}
			}
		}

	LogMsgNoIdent("--------- DNS Servers ----------");
	if (!mDNSStorage.DNSServers) LogMsgNoIdent("<None>");
	else
		{
		for (s = mDNSStorage.DNSServers; s; s = s->next)
			{
			NetworkInterfaceInfoOSX *ifx = IfindexToInterfaceInfoOSX(&mDNSStorage, s->interface);
			LogMsgNoIdent("DNS Server %##s %s%s%#a:%d %d %s %d %s",
				s->domain.c, ifx ? ifx->ifinfo.ifname : "", ifx ? " " : "", &s->addr, mDNSVal16(s->port),
				s->penaltyTime ? s->penaltyTime - mDNS_TimeNow(&mDNSStorage) : 0, s->scoped ? "Scoped" : "",
				s->timeout,
				s->teststate == DNSServer_Untested ? "(Untested)" :
				s->teststate == DNSServer_Passed   ? ""           :
				s->teststate == DNSServer_Failed   ? "(Failed)"   :
				s->teststate == DNSServer_Disabled ? "(Disabled)" : "(Unknown state)");
			}
		}

	LogMsgNoIdent("--------- Mcast Resolvers ----------");
	if (!mDNSStorage.McastResolvers) LogMsgNoIdent("<None>");
	else
		{
		for (mr = mDNSStorage.McastResolvers; mr; mr = mr->next)
			LogMsgNoIdent("Mcast Resolver %##s timeout %u", mr->domain.c, mr->timeout);
		}

	mDNSs32 now = mDNS_TimeNow(&mDNSStorage);
	LogMsgNoIdent("Timenow 0x%08lX (%d)", (mDNSu32)now, now);

	LogMsg("----  END STATE LOG  ---- %s %s %d", mDNSResponderVersionString, OSXVers ? "OSXVers" : "iOSVers", OSXVers ? OSXVers : iOSVers);
	}

#ifndef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

mDNSlocal void SignalCallback(CFMachPortRef port, void *msg, CFIndex size, void *info)
	{
	(void)port;		// Unused
	(void)size;		// Unused
	(void)info;		// Unused
	mach_msg_header_t *msg_header = (mach_msg_header_t *)msg;
	mDNS *const m = &mDNSStorage;

	// We're running on the CFRunLoop (Mach port) thread, not the kqueue thread, so we need to grab the KQueueLock before proceeding
	KQueueLock(m);
	switch(msg_header->msgh_id)
		{
		case SIGHUP:	{
						mDNSu32 slot;
						CacheGroup *cg;
						CacheRecord *rr;
						LogMsg("SIGHUP: Purge cache");
						mDNS_Lock(m);
						FORALL_CACHERECORDS(slot, cg, rr) mDNS_PurgeCacheResourceRecord(m, rr);
						// Restart unicast and multicast queries
						mDNSCoreRestartQueries(m);
						mDNS_Unlock(m);
						} break;
		case SIGINT:
		case SIGTERM:	ExitCallback(msg_header->msgh_id); break;
		case SIGINFO:	INFOCallback(); break;
		case SIGUSR1:	mDNS_LoggingEnabled = mDNS_LoggingEnabled ? 0 : 1;
						LogMsg("SIGUSR1: Logging %s", mDNS_LoggingEnabled ? "Enabled" : "Disabled");
						WatchDogReportingThreshold = mDNS_LoggingEnabled ? 50 : 250;
						break;
		case SIGUSR2:	mDNS_PacketLoggingEnabled = mDNS_PacketLoggingEnabled ? 0 : 1;
						LogMsg("SIGUSR2: Packet Logging %s", mDNS_PacketLoggingEnabled ? "Enabled" : "Disabled");
						break;
		default: LogMsg("SignalCallback: Unknown signal %d", msg_header->msgh_id); break;
		}
	KQueueUnlock(m, "Unix Signal");
	}

// On 10.2 the MachServerName is DNSServiceDiscoveryServer
// On 10.3 and later, the MachServerName is com.apple.mDNSResponder
mDNSlocal kern_return_t mDNSDaemonInitialize(void)
	{
	mStatus            err;
	CFMachPortRef      s_port;
	CFRunLoopSourceRef s_rls;
	CFRunLoopSourceRef d_rls;

	// If launchd already created our Mach port for us, then use that, else we create a new one of our own
	if (m_port != MACH_PORT_NULL)
		s_port = CFMachPortCreateWithPort(NULL, m_port, DNSserverCallback, NULL, NULL);
	else
		{
		s_port = CFMachPortCreate(NULL, DNSserverCallback, NULL, NULL);
		m_port = CFMachPortGetPort(s_port);
		kern_return_t status = bootstrap_register(bootstrap_port, "com.apple.mDNSResponder", m_port);
	
		if (status)
			{
			if (status == 1103)
				LogMsg("bootstrap_register() failed: A copy of the daemon is apparently already running");
			else
				LogMsg("bootstrap_register() failed: %d %X %s", status, status, mach_error_string(status));
			return(status);
			}
		}

	CFMachPortRef      d_port = CFMachPortCreate(NULL, ClientDeathCallback, NULL, NULL);

	err = mDNS_Init(&mDNSStorage, &PlatformStorage,
		rrcachestorage, RR_CACHE_SIZE,
		advertise,
		mDNS_StatusCallback, mDNS_Init_NoInitCallbackContext);

	if (err) { LogMsg("Daemon start: mDNS_Init failed %d", err); return(err); }

	client_death_port = CFMachPortGetPort(d_port);

	s_rls  = CFMachPortCreateRunLoopSource(NULL, s_port, 0);
	CFRunLoopAddSource(PlatformStorage.CFRunLoop, s_rls, kCFRunLoopDefaultMode);
	CFRelease(s_rls);

	d_rls  = CFMachPortCreateRunLoopSource(NULL, d_port, 0);
	CFRunLoopAddSource(PlatformStorage.CFRunLoop, d_rls, kCFRunLoopDefaultMode);
	CFRelease(d_rls);

	CFMachPortRef      i_port = CFMachPortCreate(NULL, SignalCallback, NULL, NULL);
	CFRunLoopSourceRef i_rls  = CFMachPortCreateRunLoopSource(NULL, i_port, 0);
	signal_port       = CFMachPortGetPort(i_port);
	CFRunLoopAddSource(PlatformStorage.CFRunLoop, i_rls, kCFRunLoopDefaultMode);
	CFRelease(i_rls);

	if (mDNS_DebugMode) printf("Service registered with Mach Port %d\n", m_port);
	return(err);
	}

#else // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

// SignalDispatch is mostly just a copy/paste of entire code block from SignalCallback above.
// The common code should be a subroutine, or we end up having to fix bugs in two places all the time.
// The same applies to mDNSDaemonInitialize, much of which is just a copy/paste of chunks
// of code from above. Alternatively we could remove the duplicated source code by having
// single routines, with the few differing parts bracketed with "#ifndef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM"

mDNSlocal void SignalDispatch(dispatch_source_t source)
	{
	int sig = (int)dispatch_source_get_handle(source);
	mDNS *const m = &mDNSStorage;
	KQueueLock(m);
	switch(sig)
		{
		case SIGHUP:	{
						mDNSu32 slot;
						CacheGroup *cg;
						CacheRecord *rr;
						LogMsg("SIGHUP: Purge cache");
						mDNS_Lock(m);
						FORALL_CACHERECORDS(slot, cg, rr) mDNS_PurgeCacheResourceRecord(m, rr);
						// Restart unicast and multicast queries
						mDNSCoreRestartQueries(m);
						mDNS_Unlock(m);
						} break;
		case SIGINT:
		case SIGTERM:	ExitCallback(sig); break;
		case SIGINFO:	INFOCallback(); break;
		case SIGUSR1:	mDNS_LoggingEnabled = mDNS_LoggingEnabled ? 0 : 1;
						LogMsg("SIGUSR1: Logging %s", mDNS_LoggingEnabled ? "Enabled" : "Disabled");
						WatchDogReportingThreshold = mDNS_LoggingEnabled ? 50 : 250;
						break;
		case SIGUSR2:	mDNS_PacketLoggingEnabled = mDNS_PacketLoggingEnabled ? 0 : 1;
						LogMsg("SIGUSR2: Packet Logging %s", mDNS_PacketLoggingEnabled ? "Enabled" : "Disabled");
						break;
		default: LogMsg("SignalCallback: Unknown signal %d", sig); break;
		}
	KQueueUnlock(m, "Unix Signal");
	}

mDNSlocal void mDNSSetupSignal(dispatch_queue_t queue, int sig)
	{
	signal(sig, SIG_IGN);
	dispatch_source_t source = dispatch_source_create(DISPATCH_SOURCE_TYPE_SIGNAL, sig, 0, queue);

	if (source)
		{
		dispatch_source_set_event_handler(source, ^{SignalDispatch(source);});
		// Start processing signals
		dispatch_resume(source);
		}
	else
		{
		LogMsg("mDNSSetupSignal: Cannot setup signal %d", sig);
		}
	}

// On 10.2 the MachServerName is DNSServiceDiscoveryServer
// On 10.3 and later, the MachServerName is com.apple.mDNSResponder
mDNSlocal kern_return_t mDNSDaemonInitialize(void)
	{
	mStatus            err;
	CFMachPortRef      s_port;
	dispatch_source_t mach_source;
	dispatch_queue_t queue = dispatch_get_main_queue();

	// If launchd already created our Mach port for us, then use that, else we create a new one of our own
	if (m_port != MACH_PORT_NULL)
		s_port = CFMachPortCreateWithPort(NULL, m_port, DNSserverCallback, NULL, NULL);
	else
		{
		s_port = CFMachPortCreate(NULL, DNSserverCallback, NULL, NULL);
		m_port = CFMachPortGetPort(s_port);
		kern_return_t status = bootstrap_register(bootstrap_port, "com.apple.mDNSResponder", m_port);
	
		if (status)
			{
			if (status == 1103)
				LogMsg("bootstrap_register() failed: A copy of the daemon is apparently already running");
			else
				LogMsg("bootstrap_register() failed: %d %X %s", status, status, mach_error_string(status));
			return(status);
			}
		}

	err = mDNS_Init(&mDNSStorage, &PlatformStorage,
		rrcachestorage, RR_CACHE_SIZE,
		advertise,
		mDNS_StatusCallback, mDNS_Init_NoInitCallbackContext);

	if (err) { LogMsg("Daemon start: mDNS_Init failed %d", err); return(err); }

	mach_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_MACH_RECV, m_port, 0, queue);
	if (mach_source == mDNSNULL){LogMsg("mDNSDaemonInitialize: Error creating source for m_port"); return -1;}
	dispatch_source_set_event_handler(mach_source, ^{
		dispatch_mig_server(mach_source, sizeof(union __RequestUnion__DNSServiceDiscoveryReply_subsystem),
		DNSServiceDiscoveryRequest_server);
		});
	dispatch_resume(mach_source);

	mDNSSetupSignal(queue, SIGHUP);
	mDNSSetupSignal(queue, SIGINT);
	mDNSSetupSignal(queue, SIGTERM);
	mDNSSetupSignal(queue, SIGINFO);
	mDNSSetupSignal(queue, SIGUSR1);
	mDNSSetupSignal(queue, SIGUSR2);
	mDNSSetupSignal(queue, SIGHUP);

	// Create a custom handler for doing the housekeeping work. This is either triggered
	// by the timer or an event source
	PlatformStorage.custom = dispatch_source_create(DISPATCH_SOURCE_TYPE_DATA_ADD, 0, 0, queue);
	if (PlatformStorage.custom == mDNSNULL){LogMsg("mDNSDaemonInitialize: Error creating custom source"); return -1;}
	dispatch_source_set_event_handler(PlatformStorage.custom, ^{PrepareForIdle(&mDNSStorage);});
	dispatch_resume(PlatformStorage.custom);

	// Create a timer source to trigger housekeeping work. The houskeeping work itself
	// is done in the custom handler that we set below.
	
	PlatformStorage.timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
	if (PlatformStorage.timer == mDNSNULL){LogMsg("mDNSDaemonInitialize: Error creating timer source"); return -1;}

	// As the API does not support one shot timers, we pass zero for the interval. In the custom handler, we
	// always reset the time to the new time computed. In effect, we ignore the interval
	dispatch_source_set_timer(PlatformStorage.timer, DISPATCH_TIME_NOW, 1000ull * 1000000000, 0);
	dispatch_source_set_event_handler(PlatformStorage.timer, ^{
		dispatch_source_merge_data(PlatformStorage.custom, 1);
		});
	dispatch_resume(PlatformStorage.timer);

	LogMsg("DaemonIntialize done successfully");

	if (mDNS_DebugMode) printf("Service registered with Mach Port %d\n", m_port);
	return(err);
	}

#endif // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

mDNSlocal mDNSs32 mDNSDaemonIdle(mDNS *const m)
	{
	mDNSs32 now = mDNS_TimeNow(m);

	// 1. If we need to set domain secrets, do so before handling the network change
	// Detailed reason:
	// BTMM domains listed in DynStore Setup:/Network/BackToMyMac are added to the registration domains list,
	// and we need to setup the associated AutoTunnel DomainAuthInfo entries before that happens.
	if (m->p->KeyChainTimer && now - m->p->KeyChainTimer >= 0)
		{
		m->p->KeyChainTimer = 0;
		mDNS_Lock(m);
		SetDomainSecrets(m);
		mDNS_Unlock(m);
		}

	// 2. If we have network change events to handle, do them before calling mDNS_Execute()
	// Detailed reason:
	// mDNSMacOSXNetworkChanged() currently closes and re-opens its sockets. If there are received packets waiting, they are lost.
	// mDNS_Execute() generates packets, including multicasts that are looped back to ourself.
	// If we call mDNS_Execute() first, and generate packets, and then call mDNSMacOSXNetworkChanged() immediately afterwards
	// we then systematically lose our own looped-back packets.
	if (m->p->NetworkChanged && now - m->p->NetworkChanged >= 0) mDNSMacOSXNetworkChanged(m);

	if (m->p->RequestReSleep && now - m->p->RequestReSleep >= 0) { m->p->RequestReSleep = 0; mDNSPowerRequest(0, 0); }

	// 3. Call mDNS_Execute() to let mDNSCore do what it needs to do
	mDNSs32 nextevent = mDNS_Execute(m);

	if (m->p->NetworkChanged)
		if (nextevent - m->p->NetworkChanged > 0)
			nextevent = m->p->NetworkChanged;

	if (m->p->KeyChainTimer)
		if (nextevent - m->p->KeyChainTimer > 0)
			nextevent = m->p->KeyChainTimer;

	if (m->p->RequestReSleep)
		if (nextevent - m->p->RequestReSleep > 0)
			nextevent = m->p->RequestReSleep;

	// 4. Deliver any waiting browse messages to clients
	DNSServiceBrowser *b = DNSServiceBrowserList;

	while (b)
		{
		// Note: Need to advance b to the next element BEFORE we call DeliverInstance(), because in the
		// event that the client Mach queue overflows, DeliverInstance() will call AbortBlockedClient()
		// and that will cause the DNSServiceBrowser object's memory to be freed before it returns
		DNSServiceBrowser *x = b;
		b = b->next;
		if (x->results)			// Try to deliver the list of results
			{
			while (x->results)
				{
				DNSServiceBrowserResult *const r = x->results;
				domainlabel name;
				domainname type, domain;
				DeconstructServiceName(&r->result, &name, &type, &domain);	// Don't need to check result; already validated in FoundInstance()
				char cname[MAX_DOMAIN_LABEL+1];			// Unescaped name: up to 63 bytes plus C-string terminating NULL.
				char ctype[MAX_ESCAPED_DOMAIN_NAME];
				char cdom [MAX_ESCAPED_DOMAIN_NAME];
				ConvertDomainLabelToCString_unescaped(&name, cname);
				ConvertDomainNameToCString(&type, ctype);
				ConvertDomainNameToCString(&domain, cdom);
				DNSServiceDiscoveryReplyFlags flags = (r->next) ? DNSServiceDiscoverReplyFlagsMoreComing : 0;
				kern_return_t status = DNSServiceBrowserReply_rpc(x->ClientMachPort, r->resultType, cname, ctype, cdom, flags, 1);
				// If we failed to send the mach message, try again in one second
				if (status == MACH_SEND_TIMED_OUT)
					{
					if (nextevent - now > mDNSPlatformOneSecond)
						nextevent = now + mDNSPlatformOneSecond;
					break;
					}
				else
					{
					x->lastsuccess = now;
					x->results = x->results->next;
					freeL("DNSServiceBrowserResult", r);
					}
				}
			// If this client hasn't read a single message in the last 60 seconds, abort it
			if (now - x->lastsuccess >= 60 * mDNSPlatformOneSecond)
				AbortBlockedClient(x->ClientMachPort, "browse", x);
			}
		}

	DNSServiceResolver *l;
	for (l = DNSServiceResolverList; l; l=l->next)
		if (l->ReportTime && now - l->ReportTime >= 0)
			{
			l->ReportTime = 0;
			LogMsgNoIdent("Client application bug: DNSServiceResolver(%##s) active for over two minutes. "
				"This places considerable burden on the network.", l->i.name.c);
			}

	if (m->p->NotifyUser)
		{
		if (m->p->NotifyUser - now < 0)
			{
			if (!SameDomainLabelCS(m->p->usernicelabel.c, m->nicelabel.c))
				{
				LogMsg("Name Conflict: Updated Computer Name from \"%#s\" to \"%#s\"", m->p->usernicelabel.c, m->nicelabel.c);
				mDNSPreferencesSetNames(m, kmDNSComputerName, &m->p->usernicelabel, &m->nicelabel);
				m->p->usernicelabel = m->nicelabel;
				}
			if (!SameDomainLabelCS(m->p->userhostlabel.c, m->hostlabel.c))
				{
				LogMsg("Name Conflict: Updated Local Hostname from \"%#s.local\" to \"%#s.local\"", m->p->userhostlabel.c, m->hostlabel.c);
				mDNSPreferencesSetNames(m, kmDNSLocalHostName, &m->p->userhostlabel, &m->hostlabel);
				m->p->HostNameConflict = 0;	// Clear our indicator, now name change has been successful
				m->p->userhostlabel = m->hostlabel;
				}
			m->p->NotifyUser = 0;
			}
		else
			if (nextevent - m->p->NotifyUser > 0)
				nextevent = m->p->NotifyUser;
		}

	return(nextevent);
	}

// Right now we consider *ALL* of our DHCP leases
// It might make sense to be a bit more selective and only consider the leases on interfaces
// (a) that are capable and enabled for wake-on-LAN, and
// (b) where we have found (and successfully registered with) a Sleep Proxy
// If we can't be woken for traffic on a given interface, then why keep waking to renew its lease?
mDNSlocal mDNSu32 DHCPWakeTime(void)
	{
	mDNSu32 e = 24 * 3600;		// Maximum maintenance wake interval is 24 hours
	const CFAbsoluteTime now = CFAbsoluteTimeGetCurrent();
	if (!now) LogMsg("DHCPWakeTime: CFAbsoluteTimeGetCurrent failed");
	else
		{
		const SCPreferencesRef prefs = SCPreferencesCreate(NULL, CFSTR("mDNSResponder:DHCPWakeTime"), NULL);
		if (!prefs) LogMsg("DHCPWakeTime: SCPreferencesCreate failed");
		else
			{
			const SCNetworkSetRef currentset = SCNetworkSetCopyCurrent(prefs);
			if (!currentset) LogMsg("DHCPWakeTime: SCNetworkSetCopyCurrent failed");
			else
				{
				const CFArrayRef services = SCNetworkSetCopyServices(currentset);
				if (!services) LogMsg("DHCPWakeTime: SCNetworkSetCopyServices failed");
				else
					{
					int i;
					for (i = 0; i < CFArrayGetCount(services); i++)
						{
						const SCNetworkServiceRef service = CFArrayGetValueAtIndex(services, i);
						if (!service) LogMsg("DHCPWakeTime: CFArrayGetValueAtIndex %d failed", i);
						else
							{
							const CFStringRef serviceid = SCNetworkServiceGetServiceID(service);
							if (!serviceid) LogMsg("DHCPWakeTime: SCNetworkServiceGetServiceID %d failed", i);
							else
								{
								// Note: It's normal for this call to return NULL, for interfaces not using DHCP
								const CFDictionaryRef dhcp = SCDynamicStoreCopyDHCPInfo(NULL, serviceid);
								if (dhcp)
									{
									const CFDateRef start = DHCPInfoGetLeaseStartTime(dhcp);
									const CFDataRef lease = DHCPInfoGetOptionData(dhcp, 51);	// Option 51 = IP Address Lease Time
									if (!start || !lease || CFDataGetLength(lease) < 4)
										LogMsg("DHCPWakeTime: SCDynamicStoreCopyDHCPInfo index %d failed "
											"CFDateRef start %p CFDataRef lease %p CFDataGetLength(lease) %d",
											i, start, lease, lease ? CFDataGetLength(lease) : 0);
									else
										{
										const UInt8 *d = CFDataGetBytePtr(lease);
										if (!d) LogMsg("DHCPWakeTime: CFDataGetBytePtr %d failed", i);
										else
											{
											const mDNSu32 elapsed   = now - CFDateGetAbsoluteTime(start);
											const mDNSu32 lifetime  = (mDNSs32) ((mDNSs32)d[0] << 24 | (mDNSs32)d[1] << 16 | (mDNSs32)d[2] << 8 | d[3]);
											const mDNSu32 remaining = lifetime - elapsed;
											const mDNSu32 wake      = remaining > 60 ? remaining - remaining/10 : 54;	// Wake at 90% of the lease time
											LogSPS("DHCP Address Lease Elapsed %6u Lifetime %6u Remaining %6u Wake %6u", elapsed, lifetime, remaining, wake);
											if (e > wake) e = wake;
											}
										}
									CFRelease(dhcp);
									}
								}
							}
						}
					CFRelease(services);
					}
				CFRelease(currentset);
				}
			CFRelease(prefs);
			}
		}
	return(e);
	}

// We deliberately schedule our wakeup for halfway between when we'd *like* it and when we *need* it.
// For example, if our DHCP lease expires in two hours, we'll typically renew it at the halfway point, after one hour.
// If we scheduled our wakeup for the one-hour renewal time, that might be just seconds from now, and sleeping
// for a few seconds and then waking again is silly and annoying.
// If we scheduled our wakeup for the two-hour expiry time, and we were slow to wake, we might lose our lease.
// Scheduling our wakeup for halfway in between -- 90 minutes -- avoids short wakeups while still
// allowing us an adequate safety margin to renew our lease before we lose it.

mDNSlocal mDNSBool AllowSleepNow(mDNS *const m, mDNSs32 now)
	{
	mDNSBool ready = mDNSCoreReadyForSleep(m, now);
	if (m->SleepState && !ready && now - m->SleepLimit < 0) return(mDNSfalse);

	m->p->WakeAtUTC = 0;
	int result = kIOReturnSuccess;
	CFDictionaryRef opts = NULL;

	// If the sleep request was cancelled, and we're no longer planning to sleep, don't need to
	// do the stuff below, but we *DO* still need to acknowledge the sleep message we received.
	if (!m->SleepState)
		LogMsg("AllowSleepNow: Sleep request was canceled with %d ticks remaining", m->SleepLimit - now);
	else
		{
		if (!m->SystemWakeOnLANEnabled || !mDNSCoreHaveAdvertisedMulticastServices(m))
			LogSPS("AllowSleepNow: Not scheduling wakeup: SystemWakeOnLAN %s enabled; %s advertised services",
				m->SystemWakeOnLANEnabled                  ? "is" : "not",
				mDNSCoreHaveAdvertisedMulticastServices(m) ? "have" : "no");
		else
			{
			mDNSs32 dhcp = DHCPWakeTime();
			LogSPS("ComputeWakeTime: DHCP Wake %d", dhcp);
			mDNSs32 interval = mDNSCoreIntervalToNextWake(m, now) / mDNSPlatformOneSecond;
			if (interval > dhcp) interval = dhcp;
	
			// If we're not ready to sleep (failed to register with Sleep Proxy, maybe because of
			// transient network problem) then schedule a wakeup in one hour to try again. Otherwise,
			// a single SPS failure could result in a remote machine falling permanently asleep, requiring
			// someone to go to the machine in person to wake it up again, which would be unacceptable.
			if (!ready && interval > 3600) interval = 3600;
	
			//interval = 48; // For testing
	
#ifdef kIOPMAcknowledgmentOptionSystemCapabilityRequirements
			if (m->p->IOPMConnection)	// If lightweight-wake capability is available, use that
				{
				const CFDateRef WakeDate = CFDateCreate(NULL, CFAbsoluteTimeGetCurrent() + interval);
				if (!WakeDate) LogMsg("ScheduleNextWake: CFDateCreate failed");
				else
					{
					const mDNSs32     reqs         = kIOPMSystemPowerStateCapabilityNetwork;
					const CFNumberRef Requirements = CFNumberCreate(NULL, kCFNumberSInt32Type, &reqs);
					if (!Requirements) LogMsg("ScheduleNextWake: CFNumberCreate failed");
					else
						{
						const void *OptionKeys[2] = { CFSTR("WakeDate"), CFSTR("Requirements") };
						const void *OptionVals[2] = {        WakeDate,          Requirements   };
						opts = CFDictionaryCreate(NULL, (void*)OptionKeys, (void*)OptionVals, 2, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
						if (!opts) LogMsg("ScheduleNextWake: CFDictionaryCreate failed");
						CFRelease(Requirements);
						}
					CFRelease(WakeDate);
					}
				LogSPS("AllowSleepNow: Will request lightweight wakeup in %d seconds", interval);
				}
			else 						// else schedule the wakeup using the old API instead to
#endif
				{
				// If we wake within +/- 30 seconds of our requested time we'll assume the system woke for us,
				// so we should put it back to sleep. To avoid frustrating the user, we always request at least
				// 60 seconds sleep, so if they immediately re-wake the system within seconds of it going to sleep,
				// we then shouldn't hit our 30-second window, and we won't attempt to re-sleep the machine.
				if (interval < 60) interval = 60;
	
				result = mDNSPowerRequest(1, interval);
	
				if (result == kIOReturnNotReady)
					{
					int r;
					LogMsg("AllowSleepNow: Requested wakeup in %d seconds unsuccessful; retrying with longer intervals", interval);
					// IOPMSchedulePowerEvent fails with kIOReturnNotReady (-536870184/0xe00002d8) if the
					// requested wake time is "too soon", but there's no API to find out what constitutes
					// "too soon" on any given OS/hardware combination, so if we get kIOReturnNotReady
					// we just have to iterate with successively longer intervals until it doesn't fail.
					// We preserve the value of "result" because if our original power request was deemed "too soon"
					// for the machine to get to sleep and wake back up again, we attempt to cancel the sleep request,
					// since the implication is that the system won't manage to be awake again at the time we need it.
					do
						{
						interval += (interval < 20) ? 1 : ((interval+3) / 4);
						r = mDNSPowerRequest(1, interval);
						}
					while (r == kIOReturnNotReady);
					if (r) LogMsg("AllowSleepNow: Requested wakeup in %d seconds unsuccessful: %d %X", interval, r, r);
					else LogSPS("AllowSleepNow: Requested later wakeup in %d seconds; will also attempt IOCancelPowerChange", interval);
					}
				else
					{
					if (result) LogMsg("AllowSleepNow: Requested wakeup in %d seconds unsuccessful: %d %X", interval, result, result);
					else LogSPS("AllowSleepNow: Requested wakeup in %d seconds", interval);
					}
				m->p->WakeAtUTC = mDNSPlatformUTC() + interval;
				}
			}
	
		m->SleepState = SleepState_Sleeping;
		// We used to clear our interface list to empty state here before going to sleep.
		// The applications that try to connect to an external server during maintenance wakes, saw
		// DNS resolution errors as we don't have any interfaces (most queries use SuppressUnusable
		// flag). Thus, we don't remove our interfaces anymore on sleep.
		}

	LogSPS("AllowSleepNow: %s(%lX) %s at %ld (%d ticks remaining)",
#if !TARGET_OS_EMBEDDED && defined(kIOPMAcknowledgmentOptionSystemCapabilityRequirements)
		(m->p->IOPMConnection) ? "IOPMConnectionAcknowledgeEventWithOptions" :
#endif
		(result == kIOReturnSuccess) ? "IOAllowPowerChange" : "IOCancelPowerChange",
		m->p->SleepCookie, ready ? "ready for sleep" : "giving up", now, m->SleepLimit - now);

	m->SleepLimit = 0;	// Don't clear m->SleepLimit until after we've logged it above

#if !TARGET_OS_EMBEDDED && defined(kIOPMAcknowledgmentOptionSystemCapabilityRequirements)
	if (m->p->IOPMConnection) IOPMConnectionAcknowledgeEventWithOptions(m->p->IOPMConnection, m->p->SleepCookie, opts);
	else
#endif
	if (result == kIOReturnSuccess) IOAllowPowerChange (m->p->PowerConnection, m->p->SleepCookie);
	else                            IOCancelPowerChange(m->p->PowerConnection, m->p->SleepCookie);

	if (opts) CFRelease(opts);
	return(mDNStrue);
	}

#ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

mDNSexport void TriggerEventCompletion()
	{
	debugf("TriggerEventCompletion: Merge data");
	dispatch_source_merge_data(PlatformStorage.custom, 1);
	}

mDNSlocal void PrepareForIdle(void *m_param)
	{
	mDNS            *m = m_param;
	int64_t			time_offset;
	dispatch_time_t dtime;

	const int multiplier = 1000000000 / mDNSPlatformOneSecond;
	
	// This is the main work loop:
	// (1) First we give mDNSCore a chance to finish off any of its deferred work and calculate the next sleep time
	// (2) Then we make sure we've delivered all waiting browse messages to our clients
	// (3) Then we sleep for the time requested by mDNSCore, or until the next event, whichever is sooner

	debugf("PrepareForIdle: called");
	// Run mDNS_Execute to find out the time we next need to wake up
	mDNSs32 start          = mDNSPlatformRawTime();
	mDNSs32 nextTimerEvent = udsserver_idle(mDNSDaemonIdle(m));
	mDNSs32 end            = mDNSPlatformRawTime();
	if (end - start >= WatchDogReportingThreshold)
		LogInfo("CustomSourceHandler:WARNING: Idle task took %dms to complete", end - start);

	mDNSs32 now = mDNS_TimeNow(m);

	if (m->ShutdownTime)
		{
		if (mDNSStorage.ResourceRecords)
			{
			LogInfo("Cannot exit yet; Resource Record still exists: %s", ARDisplayString(m, mDNSStorage.ResourceRecords));
			if (mDNS_LoggingEnabled) usleep(10000);		// Sleep 10ms so that we don't flood syslog with too many messages
			}
		if (mDNS_ExitNow(m, now))
			{
			if (!mDNSStorage.ResourceRecords)
				safe_vproc_transaction_end();
			LogInfo("IdleLoop: mDNS_FinalExit");
			mDNS_FinalExit(&mDNSStorage);
			usleep(1000);		// Little 1ms pause before exiting, so we don't lose our final syslog messages
			exit(0);
			}
		if (nextTimerEvent - m->ShutdownTime >= 0)
			nextTimerEvent = m->ShutdownTime;
		}

	if (m->SleepLimit)
		if (!AllowSleepNow(m, now))
			if (nextTimerEvent - m->SleepLimit >= 0)
				nextTimerEvent = m->SleepLimit;

	// Convert absolute wakeup time to a relative time from now
	mDNSs32 ticks = nextTimerEvent - now;
	if (ticks < 1) ticks = 1;
	
	static mDNSs32 RepeatedBusy = 0;	// Debugging sanity check, to guard against CPU spins
	if (ticks > 1)
		RepeatedBusy = 0;
	else
		{
		ticks = 1;
		if (++RepeatedBusy >= mDNSPlatformOneSecond) { ShowTaskSchedulingError(&mDNSStorage); RepeatedBusy = 0; }
		}

	time_offset = ((mDNSu32)ticks / mDNSPlatformOneSecond) * 1000000000 + (ticks % mDNSPlatformOneSecond) * multiplier;
	dtime = dispatch_time(DISPATCH_TIME_NOW, time_offset);
	dispatch_source_set_timer(PlatformStorage.timer, dtime, 1000ull*1000000000, 0);
	debugf("PrepareForIdle: scheduling timer with ticks %d", ticks);
	return;
	}

#else // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

mDNSlocal void KQWokenFlushBytes(int fd, __unused short filter, __unused void *context)
	{
	// Read all of the bytes so we won't wake again.
	char    buffer[100];
	while (recv(fd, buffer, sizeof(buffer), MSG_DONTWAIT) > 0) continue;
	}

mDNSlocal void * KQueueLoop(void *m_param)
	{
	mDNS            *m = m_param;
	int             numevents = 0;

#if USE_SELECT_WITH_KQUEUEFD
	fd_set          readfds;
	FD_ZERO(&readfds);
	const int multiplier = 1000000    / mDNSPlatformOneSecond;
#else
	const int multiplier = 1000000000 / mDNSPlatformOneSecond;
#endif
	
	pthread_mutex_lock(&PlatformStorage.BigMutex);
	LogInfo("Starting time value 0x%08lX (%ld)", (mDNSu32)mDNSStorage.timenow_last, mDNSStorage.timenow_last);
	
	// This is the main work loop:
	// (1) First we give mDNSCore a chance to finish off any of its deferred work and calculate the next sleep time
	// (2) Then we make sure we've delivered all waiting browse messages to our clients
	// (3) Then we sleep for the time requested by mDNSCore, or until the next event, whichever is sooner
	// (4) On wakeup we first process *all* events
	// (5) then when no more events remain, we go back to (1) to finish off any deferred work and do it all again
	for ( ; ; )
		{
		#define kEventsToReadAtOnce 1
		struct kevent new_events[kEventsToReadAtOnce];

		// Run mDNS_Execute to find out the time we next need to wake up
		mDNSs32 start          = mDNSPlatformRawTime();
		mDNSs32 nextTimerEvent = udsserver_idle(mDNSDaemonIdle(m));
		mDNSs32 end            = mDNSPlatformRawTime();
		if (end - start >= WatchDogReportingThreshold)
			LogInfo("WARNING: Idle task took %dms to complete", end - start);

		mDNSs32 now = mDNS_TimeNow(m);

		if (m->ShutdownTime)
			{
			if (mDNSStorage.ResourceRecords)
				{
				AuthRecord *rr;
				for (rr = mDNSStorage.ResourceRecords; rr; rr=rr->next)
					{
					LogInfo("Cannot exit yet; Resource Record still exists: %s", ARDisplayString(m, rr));
					if (mDNS_LoggingEnabled) usleep(10000);		// Sleep 10ms so that we don't flood syslog with too many messages
					}
				}
			if (mDNS_ExitNow(m, now))
				{
				if (!mDNSStorage.ResourceRecords)
					safe_vproc_transaction_end();
				LogInfo("mDNS_FinalExit");
				mDNS_FinalExit(&mDNSStorage);
				usleep(1000);		// Little 1ms pause before exiting, so we don't lose our final syslog messages
				exit(0);
				}
			if (nextTimerEvent - m->ShutdownTime >= 0)
				nextTimerEvent = m->ShutdownTime;
			}

		if (m->SleepLimit)
			if (!AllowSleepNow(m, now))
				if (nextTimerEvent - m->SleepLimit >= 0)
					nextTimerEvent = m->SleepLimit;

		// Convert absolute wakeup time to a relative time from now
		mDNSs32 ticks = nextTimerEvent - now;
		if (ticks < 1) ticks = 1;
		
		static mDNSs32 RepeatedBusy = 0;	// Debugging sanity check, to guard against CPU spins
		if (ticks > 1)
			RepeatedBusy = 0;
		else
			{
			ticks = 1;
			if (++RepeatedBusy >= mDNSPlatformOneSecond) { ShowTaskSchedulingError(&mDNSStorage); RepeatedBusy = 0; }
			}

		verbosedebugf("KQueueLoop: Handled %d events; now sleeping for %d ticks", numevents, ticks);
		numevents = 0;

		// Release the lock, and sleep until:
		// 1. Something interesting happens like a packet arriving, or
		// 2. The other thread writes a byte to WakeKQueueLoopFD to poke us and make us wake up, or
		// 3. The timeout expires
		pthread_mutex_unlock(&PlatformStorage.BigMutex);

#if USE_SELECT_WITH_KQUEUEFD
		struct timeval timeout;
		timeout.tv_sec = ticks / mDNSPlatformOneSecond;
		timeout.tv_usec = (ticks % mDNSPlatformOneSecond) * multiplier;
		FD_SET(KQueueFD, &readfds);
		if (select(KQueueFD+1, &readfds, NULL, NULL, &timeout) < 0)
			{ LogMsg("select(%d) failed errno %d (%s)", KQueueFD, errno, strerror(errno)); sleep(1); }
#else
		struct timespec timeout;
		timeout.tv_sec = ticks / mDNSPlatformOneSecond;
		timeout.tv_nsec = (ticks % mDNSPlatformOneSecond) * multiplier;
		// In my opinion, you ought to be able to call kevent() with nevents set to zero,
		// and have it work similarly to the way it does with nevents non-zero --
		// i.e. it waits until either an event happens or the timeout expires, and then wakes up.
		// In fact, what happens if you do this is that it just returns immediately. So, we have
		// to pass nevents set to one, and then we just ignore the event it gives back to us. -- SC
		if (kevent(KQueueFD, NULL, 0, new_events, 1, &timeout) < 0)
			{ LogMsg("kevent(%d) failed errno %d (%s)", KQueueFD, errno, strerror(errno)); sleep(1); }
#endif

		pthread_mutex_lock(&PlatformStorage.BigMutex);
		// We have to ignore the event we may have been told about above, because that
		// was done without holding the lock, and between the time we woke up and the
		// time we reclaimed the lock the other thread could have done something that
		// makes the event no longer valid. Now we have the lock, we call kevent again
		// and this time we can safely process the events it tells us about.

		static const struct timespec zero_timeout = { 0, 0 };
		int events_found;
		while ((events_found = kevent(KQueueFD, NULL, 0, new_events, kEventsToReadAtOnce, &zero_timeout)) != 0)
			{
			if (events_found > kEventsToReadAtOnce || (events_found < 0 && errno != EINTR))
				{
				// Not sure what to do here, our kqueue has failed us - this isn't ideal
				LogMsg("ERROR: KQueueLoop - kevent failed errno %d (%s)", errno, strerror(errno));
				exit(errno);
				}

			numevents += events_found;

			int i;
			for (i = 0; i < events_found; i++)
				{
				const KQueueEntry *const kqentry = new_events[i].udata;
				mDNSs32 stime = mDNSPlatformRawTime();
				const char *const KQtask = kqentry->KQtask;	// Grab a copy in case KQcallback deletes the task
				kqentry->KQcallback(new_events[i].ident, new_events[i].filter, kqentry->KQcontext);
				mDNSs32 etime = mDNSPlatformRawTime();
				if (etime - stime >= WatchDogReportingThreshold)
					LogInfo("WARNING: %s took %dms to complete", KQtask, etime - stime);
				}
			}
		}
	
	return NULL;
	}

#endif // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

mDNSlocal void LaunchdCheckin(void)
	{
	launch_data_t msg  = launch_data_new_string(LAUNCH_KEY_CHECKIN);
	launch_data_t resp = launch_msg(msg);
	launch_data_free(msg);
	if (!resp) { LogMsg("launch_msg returned NULL"); return; }

	if (launch_data_get_type(resp) == LAUNCH_DATA_ERRNO)
		{
		int err = launch_data_get_errno(resp);
		// When running on Tiger with "ServiceIPC = false", we get "err == EACCES" to tell us there's no launchdata to fetch
		if (err != EACCES) LogMsg("launch_msg returned %d", err);
		else LogInfo("Launchd provided no launchdata; will open Mach port and Unix Domain Socket explicitly...", err);
		}
	else
		{
		launch_data_t skts = launch_data_dict_lookup(resp, LAUNCH_JOBKEY_SOCKETS);
		if (!skts) LogMsg("launch_data_dict_lookup LAUNCH_JOBKEY_SOCKETS returned NULL");
		else
			{
			launch_data_t skt = launch_data_dict_lookup(skts, "Listeners");
			if (!skt) LogMsg("launch_data_dict_lookup Listeners returned NULL");
			else
				{
				launchd_fds_count = launch_data_array_get_count(skt);
				if (launchd_fds_count == 0) LogMsg("launch_data_array_get_count(skt) returned 0");
				else
					{
					launchd_fds = mallocL("LaunchdCheckin", sizeof(dnssd_sock_t) * launchd_fds_count);
					if (!launchd_fds) LogMsg("LaunchdCheckin: malloc failed");
					else
						{
						size_t i;
						for(i = 0; i < launchd_fds_count; i++)
							{						
							launch_data_t s = launch_data_array_get_index(skt, i);
							if (!s)
								{
								launchd_fds[i] = dnssd_InvalidSocket;
								LogMsg("launch_data_array_get_index(skt, %d) returned NULL", i);
								}
							else
								{
								launchd_fds[i] = launch_data_get_fd(s);
								LogInfo("Launchd Unix Domain Socket [%d]: %d", i, launchd_fds[i]);
								}
							}
						}
					// In some early versions of 10.4.x, the permissions on the UDS were not set correctly, so we fix them here
					chmod(MDNS_UDS_SERVERPATH, S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP | S_IROTH|S_IWOTH);
					}
				}
			}

		launch_data_t ports = launch_data_dict_lookup(resp, "MachServices");
		if (!ports) LogMsg("launch_data_dict_lookup MachServices returned NULL");
		else
			{
			launch_data_t p = launch_data_dict_lookup(ports, "com.apple.mDNSResponder");
			if (!p) LogInfo("launch_data_dict_lookup(ports, \"com.apple.mDNSResponder\") returned NULL");
			else
				{
				m_port = launch_data_get_fd(p);
				LogInfo("Launchd Mach Port: %d", m_port);
				if (m_port == ~0U) m_port = MACH_PORT_NULL;
				}
			}
		}
	launch_data_free(resp);
	}

mDNSlocal void DropPrivileges(void)
	{
	static const char login[] = "_mdnsresponder";
	struct passwd *pwd = getpwnam(login);
	if (NULL == pwd)
		LogMsg("Could not find account name \"%s\". Running as root.", login);
	else
		{
		uid_t uid = pwd->pw_uid;
		gid_t gid = pwd->pw_gid;

		LogMsg("Started as root. Switching to userid \"%s\".", login);

		if (unlink(MDNS_UDS_SERVERPATH) < 0 && errno != ENOENT) LogMsg("DropPrivileges: Could not unlink \"%s\": (%d) %s", MDNS_UDS_SERVERPATH, errno, strerror(errno));
		else
			{
			static char path[] = "/var/run/mdns/mDNSResponder";
			char *p = strrchr(path, '/');
			*p = '\0';
			if (mkdir(path, 0755) < 0 && errno != EEXIST) LogMsg("DropPrivileges: Could not create directory \"%s\": (%d) %s", path, errno, strerror(errno));
			else if (chown(path, uid, gid) < 0) LogMsg("DropPrivileges: Could not chown directory \"%s\": (%d) %s", path, errno, strerror(errno));
			else
				{
				*p = '/';
				if (unlink(path) < 0 && errno != ENOENT) LogMsg("DropPrivileges: Could not unlink \"%s\": (%d) %s", path, errno, strerror(errno));
				else if (symlink(path, MDNS_UDS_SERVERPATH) < 0) LogMsg("DropPrivileges: Could not symlink \"%s\" -> \"%s\": (%d) %s", MDNS_UDS_SERVERPATH, path, errno, strerror(errno));
				else LogInfo("DropPrivileges: Created subdirectory and symlink");
				}
			}

		if (0 != initgroups(login, gid)) LogMsg("initgroups(\"%s\", %lu) failed.  Continuing.", login,        (unsigned long)gid);
		if (0 != setgid(gid))            LogMsg("setgid(%lu) failed.  Continuing with group %lu privileges.", (unsigned long)getegid());
		if (0 != setuid(uid))            LogMsg("setuid(%lu) failed. Continuing as root after all.",          (unsigned long)uid);
		}
	}

extern int sandbox_init(const char *profile, uint64_t flags, char **errorbuf) __attribute__((weak_import));

mDNSexport int main(int argc, char **argv)
	{
	int i;
	kern_return_t status;

	mDNSMacOSXSystemBuildNumber(NULL);
	LogMsg("%s starting %s %d", mDNSResponderVersionString, OSXVers ? "OSXVers" : "iOSVers", OSXVers ? OSXVers : iOSVers);
	
#if 0
	LogMsg("CacheRecord %d", sizeof(CacheRecord));
	LogMsg("CacheGroup  %d", sizeof(CacheGroup));
	LogMsg("ResourceRecord  %d", sizeof(ResourceRecord));
	LogMsg("RData_small     %d", sizeof(RData_small));

	LogMsg("sizeof(CacheEntity) %d", sizeof(CacheEntity));
	LogMsg("RR_CACHE_SIZE       %d", RR_CACHE_SIZE);
	LogMsg("block usage         %d", sizeof(CacheEntity) * RR_CACHE_SIZE);
	LogMsg("block wastage       %d", 16*1024 - sizeof(CacheEntity) * RR_CACHE_SIZE);
#endif

	safe_vproc_transaction_begin();

	if (0 == geteuid()) DropPrivileges();

	for (i=1; i<argc; i++)
		{
		if (!strcasecmp(argv[i], "-d"                        )) mDNS_DebugMode            = mDNStrue;
		if (!strcasecmp(argv[i], "-launchd"                  )) started_via_launchdaemon  = mDNStrue;
		if (!strcasecmp(argv[i], "-launchdaemon"             )) started_via_launchdaemon  = mDNStrue;
		if (!strcasecmp(argv[i], "-NoMulticastAdvertisements")) advertise                 = mDNS_Init_DontAdvertiseLocalAddresses;
		if (!strcasecmp(argv[i], "-DisableSleepProxyClient"  )) DisableSleepProxyClient   = mDNStrue;
		if (!strcasecmp(argv[i], "-DebugLogging"             )) mDNS_LoggingEnabled       = mDNStrue;
		if (!strcasecmp(argv[i], "-UnicastPacketLogging"     )) mDNS_PacketLoggingEnabled = mDNStrue;
		if (!strcasecmp(argv[i], "-OfferSleepProxyService"   ))
			OfferSleepProxyService = (i+1 < argc && mDNSIsDigit(argv[i+1][0]) && mDNSIsDigit(argv[i+1][1]) && argv[i+1][2]==0) ? atoi(argv[++i]) : 100;
		if (!strcasecmp(argv[i], "-UseInternalSleepProxy"    ))
			UseInternalSleepProxy = (i+1<argc && mDNSIsDigit(argv[i+1][0]) && argv[i+1][1]==0) ? atoi(argv[++i]) : 1;
		if (!strcasecmp(argv[i], "-StrictUnicastOrdering"    )) StrictUnicastOrdering     = mDNStrue;
		if (!strcasecmp(argv[i], "-DisableInboundRelay"      )) DisableInboundRelayConnection = mDNStrue;
		if (!strcasecmp(argv[i], "-AlwaysAppendSearchDomains")) AlwaysAppendSearchDomains = mDNStrue;
		}
	
	// Note that mDNSPlatformInit will set DivertMulticastAdvertisements in the mDNS structure
	if (!advertise) LogMsg("Administratively prohibiting multicast advertisements");

#ifndef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

	signal(SIGHUP,  HandleSIG);		// (Debugging) Purge the cache to check for cache handling bugs
	signal(SIGINT,  HandleSIG);		// Ctrl-C: Detach from Mach BootstrapService and exit cleanly
	signal(SIGPIPE, SIG_IGN  );		// Don't want SIGPIPE signals -- we'll handle EPIPE errors directly
	signal(SIGTERM, HandleSIG);		// Machine shutting down: Detach from and exit cleanly like Ctrl-C
	signal(SIGINFO, HandleSIG);		// (Debugging) Write state snapshot to syslog
	signal(SIGUSR1, HandleSIG);		// (Debugging) Enable Logging
	signal(SIGUSR2, HandleSIG);		// (Debugging) Enable Packet Logging

#endif // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

	mDNSStorage.p = &PlatformStorage;	// Make sure mDNSStorage.p is set up, because validatelists uses it
	LaunchdCheckin();

	// Register the server with mach_init for automatic restart only during normal (non-debug) mode
    if (!mDNS_DebugMode && !started_via_launchdaemon)
    	{
    	registerBootstrapService();
    	if (!restarting_via_mach_init) exit(0); // mach_init will restart us immediately as a daemon
		int fd = open(_PATH_DEVNULL, O_RDWR, 0);
		if (fd < 0) LogMsg("open(_PATH_DEVNULL, O_RDWR, 0) failed errno %d (%s)", errno, strerror(errno));
		else
			{
			// Avoid unnecessarily duplicating a file descriptor to itself
			if (fd != STDIN_FILENO)  if (dup2(fd, STDIN_FILENO)  < 0) LogMsg("dup2(fd, STDIN_FILENO)  failed errno %d (%s)", errno, strerror(errno));
			if (fd != STDOUT_FILENO) if (dup2(fd, STDOUT_FILENO) < 0) LogMsg("dup2(fd, STDOUT_FILENO) failed errno %d (%s)", errno, strerror(errno));
			if (fd != STDERR_FILENO) if (dup2(fd, STDERR_FILENO) < 0) LogMsg("dup2(fd, STDERR_FILENO) failed errno %d (%s)", errno, strerror(errno));
			if (fd != STDIN_FILENO && fd != STDOUT_FILENO && fd != STDERR_FILENO) (void)close(fd);
			}
		}

#ifndef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

	// Create the kqueue, mutex and thread to support KQSockets
	KQueueFD = kqueue();
	if (KQueueFD == -1) { LogMsg("kqueue() failed errno %d (%s)", errno, strerror(errno)); status = errno; goto exit; }
	
	i = pthread_mutex_init(&PlatformStorage.BigMutex, NULL);
	if (i == -1) { LogMsg("pthread_mutex_init() failed errno %d (%s)", errno, strerror(errno)); status = errno; goto exit; }
	
	int fdpair[2] = {0, 0};
	i = socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair);
	if (i == -1) { LogMsg("socketpair() failed errno %d (%s)", errno, strerror(errno)); status = errno; goto exit; }

	// Socket pair returned us two identical sockets connected to each other
	// We will use the first socket to send the second socket. The second socket
	// will be added to the kqueue so it will wake when data is sent.
	static const KQueueEntry wakeKQEntry = { KQWokenFlushBytes, NULL, "kqueue wakeup after CFRunLoop event" };

	PlatformStorage.WakeKQueueLoopFD = fdpair[0];
	KQueueSet(fdpair[1], EV_ADD, EVFILT_READ, &wakeKQEntry);

#endif // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
	
	// Invoke sandbox profile /usr/share/sandbox/mDNSResponder.sb
#if MDNS_NO_SANDBOX
	LogMsg("Note: Compiled without Apple Sandbox support");
#else MDNS_NO_SANDBOX
	if (!sandbox_init)
		LogMsg("Note: Running without Apple Sandbox support (not available on this OS)");
	else
		{
		char *sandbox_msg;
		uint64_t sandbox_flags = SANDBOX_NAMED;

		// On Desktop, the sandbox profile always exists under /usr/share/sandbox, no need to
		// check it. stat results in calls to opendirectoryd and to avoid deadlocks with
		// opendirectoryd early on, we avoid this call.
#if TARGET_OS_EMBEDDED
		struct stat s;
		if (stat("/usr/share/sandbox/mDNSResponder.sb", &s) == 0)
			{
			sandbox_flags = SANDBOX_NAMED_EXTERNAL;
			LogInfo("Will load Sandbox profile from filesystem");
			}
#endif

		int sandbox_err = sandbox_init("mDNSResponder", sandbox_flags, &sandbox_msg);
		if (sandbox_err) { LogMsg("WARNING: sandbox_init error %s", sandbox_msg); sandbox_free_error(sandbox_msg); }
		else LogInfo("Now running under Apple Sandbox restrictions");
		}
#endif // MDNS_NO_SANDBOX

	status = mDNSDaemonInitialize();
	if (status) { LogMsg("Daemon start: mDNSDaemonInitialize failed"); goto exit; }

	status = udsserver_init(launchd_fds, launchd_fds_count);
	if (status) { LogMsg("Daemon start: udsserver_init failed"); goto exit; }

	mDNSMacOSXNetworkChanged(&mDNSStorage);

#ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
	LogInfo("Daemon Start: Using LibDispatch");
	// CFRunLoopRun runs both CFRunLoop sources and dispatch sources
	CFRunLoopRun();
#else // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
	// Start the kqueue thread
	pthread_t KQueueThread;
	i = pthread_create(&KQueueThread, NULL, KQueueLoop, &mDNSStorage);
	if (i == -1) { LogMsg("pthread_create() failed errno %d (%s)", errno, strerror(errno)); status = errno; goto exit; }
	if (status == 0)
		{
		CFRunLoopRun();
		LogMsg("ERROR: CFRunLoopRun Exiting.");
		mDNS_Close(&mDNSStorage);
		}
#endif // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

	LogMsg("%s exiting", mDNSResponderVersionString);

exit:
	if (!mDNS_DebugMode && !started_via_launchdaemon) destroyBootstrapService();
	return(status);
	}

// uds_daemon.c support routines /////////////////////////////////////////////

// Arrange things so that when data appears on fd, callback is called with context
mDNSexport mStatus udsSupportAddFDToEventLoop(int fd, udsEventCallback callback, void *context, void **platform_data)
	{
	KQSocketEventSource **p = &gEventSources;
	(void) platform_data;
	while (*p && (*p)->fd != fd) p = &(*p)->next;
	if (*p) { LogMsg("udsSupportAddFDToEventLoop: ERROR fd %d already has EventLoop source entry", fd); return mStatus_AlreadyRegistered; }

	KQSocketEventSource *newSource = (KQSocketEventSource*) mallocL("KQSocketEventSource", sizeof *newSource);
	if (!newSource) return mStatus_NoMemoryErr;

	newSource->next           = mDNSNULL;
	newSource->fd             = fd;
	newSource->kqs.KQcallback = callback;
	newSource->kqs.KQcontext  = context;
	newSource->kqs.KQtask     = "UDS client";
#ifdef MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM
	newSource->kqs.readSource  = mDNSNULL;
	newSource->kqs.writeSource = mDNSNULL;
	newSource->kqs.fdClosed    = mDNSfalse;
#endif // MDNSRESPONDER_USES_LIB_DISPATCH_AS_PRIMARY_EVENT_LOOP_MECHANISM

	if (KQueueSet(fd, EV_ADD, EVFILT_READ, &newSource->kqs) == 0)
		{
		*p = newSource;
		return mStatus_NoError;
		}

	LogMsg("KQueueSet failed for fd %d errno %d (%s)", fd, errno, strerror(errno));
	freeL("KQSocketEventSource", newSource);
	return mStatus_BadParamErr;
	}

int udsSupportReadFD(dnssd_sock_t fd, char *buf, int len, int flags, void *platform_data)
	{
	(void) platform_data;
	return recv(fd, buf, len, flags);
	}

mDNSexport mStatus udsSupportRemoveFDFromEventLoop(int fd, void *platform_data)		// Note: This also CLOSES the file descriptor
	{
	KQSocketEventSource **p = &gEventSources;
	(void) platform_data;
	while (*p && (*p)->fd != fd) p = &(*p)->next;
	if (*p)
		{
		KQSocketEventSource *s = *p;
		*p = (*p)->next;
		// We don't have to explicitly do a kqueue EV_DELETE here because closing the fd
		// causes the kernel to automatically remove any associated kevents
		mDNSPlatformCloseFD(&s->kqs, s->fd);
		freeL("KQSocketEventSource", s);
		return mStatus_NoError;
		}
	LogMsg("udsSupportRemoveFDFromEventLoop: ERROR fd %d not found in EventLoop source list", fd);
	return mStatus_NoSuchNameErr;
	}

#if _BUILDING_XCODE_PROJECT_
// If mDNSResponder crashes, then this string will be magically included in the automatically-generated crash log
const char *__crashreporter_info__ = mDNSResponderVersionString;
asm(".desc ___crashreporter_info__, 0x10");
#endif

// For convenience when using the "strings" command, this is the last thing in the file
// The "@(#) " pattern is a special prefix the "what" command looks for
mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder " STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ")";