1/* -*- Mode: C; tab-width: 4 -*-
2 *
3 * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16
17	File:		daemon.c
18
19	Contains:	main & associated Application layer for mDNSResponder on Linux.
20
21	Change History (most recent first):
22
23Log: PosixDaemon.c,v $
24Revision 1.49  2009/04/30 20:07:51  mcguire
25<rdar://problem/6822674> Support multiple UDSs from launchd
26
27Revision 1.48  2009/04/11 01:43:28  jessic2
28<rdar://problem/4426780> Daemon: Should be able to turn on LogOperation dynamically
29
30Revision 1.47  2009/01/11 03:20:06  mkrochma
31<rdar://problem/5797526> Fixes from Igor Seleznev to get mdnsd working on Solaris
32
33Revision 1.46  2008/11/03 23:09:15  cheshire
34Don't need to include mDNSDebug.h as well as mDNSEmbeddedAPI.h
35
36Revision 1.45  2008/10/03 18:25:17  cheshire
37Instead of calling "m->MainCallback" function pointer directly, call mDNSCore routine "mDNS_ConfigChanged(m);"
38
39Revision 1.44  2008/09/15 23:52:30  cheshire
40<rdar://problem/6218902> mDNSResponder-177 fails to compile on Linux with .desc pseudo-op
41Made __crashreporter_info__ symbol conditional, so we only use it for OS X build
42
43Revision 1.43  2007/10/22 20:05:34  cheshire
44Use mDNSPlatformSourceAddrForDest instead of FindSourceAddrForIP
45
46Revision 1.42  2007/09/18 19:09:02  cheshire
47<rdar://problem/5489549> mDNSResponderHelper (and other binaries) missing SCCS version strings
48
49Revision 1.41  2007/09/04 17:02:25  cheshire
50<rdar://problem/5458929> False positives in changed files list in nightly builds
51Added MDNS_VERSIONSTR_NODTS option at the reqest of Rishi Srivatsavai (Sun)
52
53Revision 1.40  2007/07/31 23:08:34  mcguire
54<rdar://problem/5329542> BTMM: Make AutoTunnel mode work with multihoming
55
56Revision 1.39  2007/03/21 00:30:44  cheshire
57Remove obsolete mDNS_DeleteDNSServers() call
58
59Revision 1.38  2007/02/14 01:58:19  cheshire
60<rdar://problem/4995831> Don't delete Unix Domain Socket on exit if we didn't create it on startup
61
62Revision 1.37  2007/02/07 19:32:00  cheshire
63<rdar://problem/4980353> All mDNSResponder components should contain version strings in SCCS-compatible format
64
65Revision 1.36  2007/02/06 19:06:48  cheshire
66<rdar://problem/3956518> Need to go native with launchd
67
68Revision 1.35  2007/01/05 08:30:52  cheshire
69Trim excessive "Log" checkin history from before 2006
70(checkin history still available via "cvs log ..." of course)
71
72Revision 1.34  2007/01/05 05:46:08  cheshire
73Add mDNS *const m parameter to udsserver_handle_configchange()
74
75Revision 1.33  2006/12/21 00:10:53  cheshire
76Make mDNS_PlatformSupport PlatformStorage a static global instead of a stack variable
77
78Revision 1.32  2006/11/03 22:28:50  cheshire
79PosixDaemon needs to handle mStatus_ConfigChanged and mStatus_GrowCache messages
80
81Revision 1.31  2006/08/14 23:24:46  cheshire
82Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0
83
84Revision 1.30  2006/07/07 01:09:12  cheshire
85<rdar://problem/4472013> Add Private DNS server functionality to dnsextd
86Only use mallocL/freeL debugging routines when building mDNSResponder, not dnsextd
87
88*/
89
90#include <stdio.h>
91#include <string.h>
92#include <unistd.h>
93#include <stdlib.h>
94#include <signal.h>
95#include <errno.h>
96#include <fcntl.h>
97#include <pwd.h>
98#include <sys/types.h>
99
100#include "mDNSEmbeddedAPI.h"
101#include "mDNSPosix.h"
102#include "mDNSUNP.h"		// For daemon()
103#include "uds_daemon.h"
104#include "DNSCommon.h"
105#include "PlatformCommon.h"
106
107#ifndef MDNSD_USER
108#define MDNSD_USER "nobody"
109#endif
110
111#define CONFIG_FILE "/etc/mdnsd.conf"
112static domainname DynDNSZone;                // Default wide-area zone for service registration
113static domainname DynDNSHostname;
114
115#define RR_CACHE_SIZE 500
116static CacheEntity gRRCache[RR_CACHE_SIZE];
117static mDNS_PlatformSupport PlatformStorage;
118
119mDNSlocal void mDNS_StatusCallback(mDNS *const m, mStatus result)
120	{
121	(void)m; // Unused
122	if (result == mStatus_NoError)
123		{
124		// On successful registration of dot-local mDNS host name, daemon may want to check if
125		// any name conflict and automatic renaming took place, and if so, record the newly negotiated
126		// name in persistent storage for next time. It should also inform the user of the name change.
127		// On Mac OS X we store the current dot-local mDNS host name in the SCPreferences store,
128		// and notify the user with a CFUserNotification.
129		}
130	else if (result == mStatus_ConfigChanged)
131		{
132		udsserver_handle_configchange(m);
133		}
134	else if (result == mStatus_GrowCache)
135		{
136		// Allocate another chunk of cache storage
137		CacheEntity *storage = malloc(sizeof(CacheEntity) * RR_CACHE_SIZE);
138		if (storage) mDNS_GrowCache(m, storage, RR_CACHE_SIZE);
139		}
140	}
141
142// %%% Reconfigure() probably belongs in the platform support layer (mDNSPosix.c), not the daemon cde
143// -- all client layers running on top of mDNSPosix.c need to handle network configuration changes,
144// not only the Unix Domain Socket Daemon
145
146static void Reconfigure(mDNS *m)
147	{
148	mDNSAddr DynDNSIP;
149	const mDNSAddr dummy = { mDNSAddrType_IPv4, { { { 1, 1, 1, 1 } } } };;
150	mDNS_SetPrimaryInterfaceInfo(m, NULL, NULL, NULL);
151        mDNS_Lock(m);
152	if (ParseDNSServers(m, uDNS_SERVERS_FILE) < 0)
153		LogMsg("Unable to parse DNS server list. Unicast DNS-SD unavailable");
154        mDNS_Unlock(m);
155	ReadDDNSSettingsFromConfFile(m, CONFIG_FILE, &DynDNSHostname, &DynDNSZone, NULL);
156	mDNSPlatformSourceAddrForDest(&DynDNSIP, &dummy);
157	if (DynDNSHostname.c[0]) mDNS_AddDynDNSHostName(m, &DynDNSHostname, NULL, NULL);
158	if (DynDNSIP.type)       mDNS_SetPrimaryInterfaceInfo(m, &DynDNSIP, NULL, NULL);
159	mDNS_ConfigChanged(m);
160	}
161
162// Do appropriate things at startup with command line arguments. Calls exit() if unhappy.
163mDNSlocal void ParseCmdLinArgs(int argc, char **argv)
164	{
165	if (argc > 1)
166		{
167		if (0 == strcmp(argv[1], "-debug")) mDNS_DebugMode = mDNStrue;
168		else printf("Usage: %s [-debug]\n", argv[0]);
169		}
170
171	if (!mDNS_DebugMode)
172		{
173		int result = daemon(0, 0);
174		if (result != 0) { LogMsg("Could not run as daemon - exiting"); exit(result); }
175#if __APPLE__
176		LogMsg("The POSIX mdnsd should only be used on OS X for testing - exiting");
177		exit(-1);
178#endif
179		}
180	}
181
182mDNSlocal void DumpStateLog(mDNS *const m)
183// Dump a little log of what we've been up to.
184	{
185	DNSServer *s;
186        PosixNetworkInterface *i;
187
188	LogMsg("---- BEGIN STATE LOG ----");
189	udsserver_info(m);
190
191        LogMsgNoIdent("----- Network Interfaces -------");
192        for (i = (PosixNetworkInterface*)(m->HostInterfaces);
193        i; i = (PosixNetworkInterface *)(i->coreIntf.next)) {
194            LogMsg("%p %p %d %s%s%s%s%s %-8s %#a", i,
195            (void *)(i->coreIntf.InterfaceID), i->index,
196            i->coreIntf.InterfaceActive ? "-" : "D",
197            i->coreIntf.IPv4Available ? "4" : "-",
198            i->coreIntf.IPv6Available ? "6" : "-",
199            i->coreIntf.Advertise ? "A" : "-",
200            i->coreIntf.McastTxRx ? "M" : "-",
201            i->intfName, &(i->coreIntf.ip));
202        }
203
204        LogMsgNoIdent("--------- DNS Servers ----------");
205        if (!mDNSStorage.DNSServers) LogMsgNoIdent("<None>");
206        else
207                {
208                for (s = m->DNSServers; s; s = s->next)
209                        {
210                        LogMsgNoIdent("DNS Server %##s %#a:%d %s",
211                                s->domain.c, &s->addr, mDNSVal16(s->port),
212                                s->teststate == DNSServer_Untested ? "(Untested)" :
213                                s->teststate == DNSServer_Passed   ? ""           :
214                                s->teststate == DNSServer_Failed   ? "(Failed)"   :
215                                s->teststate == DNSServer_Disabled ? "(Disabled)" : "(Unknown state)");
216                        }
217                }
218
219	LogMsg("----  END STATE LOG  ----");
220	}
221
222mDNSlocal mStatus MainLoop(mDNS *m) // Loop until we quit.
223	{
224	sigset_t	signals;
225	mDNSBool	gotData = mDNSfalse;
226
227	mDNSPosixListenForSignalInEventLoop(SIGINT);
228	mDNSPosixListenForSignalInEventLoop(SIGTERM);
229	mDNSPosixListenForSignalInEventLoop(SIGUSR1);
230#ifdef HAVE_SIGINFO
231	mDNSPosixListenForSignalInEventLoop(SIGUSR2);
232	mDNSPosixListenForSignalInEventLoop(SIGINFO);
233#endif
234	mDNSPosixListenForSignalInEventLoop(SIGPIPE);
235	mDNSPosixListenForSignalInEventLoop(SIGHUP) ;
236
237	for (; ;)
238		{
239		// Work out how long we expect to sleep before the next scheduled task
240		struct timeval	timeout;
241		mDNSs32			ticks;
242
243		// Only idle if we didn't find any data the last time around
244		if (!gotData)
245			{
246			mDNSs32			nextTimerEvent = mDNS_Execute(m);
247			nextTimerEvent = udsserver_idle(nextTimerEvent);
248			ticks = nextTimerEvent - mDNS_TimeNow(m);
249			if (ticks < 1) ticks = 1;
250			}
251		else	// otherwise call EventLoop again with 0 timemout
252			ticks = 0;
253
254		timeout.tv_sec = ticks / mDNSPlatformOneSecond;
255		timeout.tv_usec = (ticks % mDNSPlatformOneSecond) * 1000000 / mDNSPlatformOneSecond;
256
257		(void) mDNSPosixRunEventLoopOnce(m, &timeout, &signals, &gotData);
258
259		if (sigismember(&signals, SIGHUP )) Reconfigure(m);
260#ifdef HAVE_SIGINFO
261                /* use OSX-compatible signals since we can, and gain enhanced debugging */
262		if (sigismember(&signals, SIGINFO)) DumpStateLog(m);
263		if (sigismember(&signals, SIGUSR1))
264			{
265		        mDNS_LoggingEnabled = mDNS_LoggingEnabled ? 0 : 1;
266		        LogMsg("SIGUSR1: Logging %s", mDNS_LoggingEnabled ? "Enabled" : "Disabled");
267			}
268		if (sigismember(&signals, SIGUSR2))
269			{
270			mDNS_PacketLoggingEnabled = mDNS_PacketLoggingEnabled ? 0 : 1;
271			LogMsg("SIGUSR2: Packet Logging %s", mDNS_PacketLoggingEnabled ? "Enabled" : "Disabled");
272			}
273#else
274		if (sigismember(&signals, SIGUSR1)) DumpStateLog(m);
275#endif
276		// SIGPIPE happens when we try to write to a dead client; death should be detected soon in request_callback() and cleaned up.
277		if (sigismember(&signals, SIGPIPE)) LogMsg("Received SIGPIPE - ignoring");
278		if (sigismember(&signals, SIGINT) || sigismember(&signals, SIGTERM)) break;
279		}
280	return EINTR;
281	}
282
283int main(int argc, char **argv)
284	{
285	mStatus					err;
286
287	ParseCmdLinArgs(argc, argv);
288
289	LogMsg("%s starting", mDNSResponderVersionString);
290
291	err = mDNS_Init(&mDNSStorage, &PlatformStorage, gRRCache, RR_CACHE_SIZE, mDNS_Init_AdvertiseLocalAddresses,
292					mDNS_StatusCallback, mDNS_Init_NoInitCallbackContext);
293
294	if (mStatus_NoError == err)
295		err = udsserver_init(mDNSNULL, 0);
296
297	Reconfigure(&mDNSStorage);
298
299	// Now that we're finished with anything privileged, switch over to running as "nobody"
300	if (mStatus_NoError == err)
301		{
302		const struct passwd *pw = getpwnam(MDNSD_USER);
303		if (pw != NULL)
304		        {
305			setgid(pw->pw_gid);
306			setuid(pw->pw_uid);
307		        }
308		else
309#ifdef MDNSD_NOROOT
310                        {
311    			LogMsg("WARNING: mdnsd exiting because user \""MDNSD_USER"\" does not exist");
312                        err = mStatus_Invalid;
313                        }
314#else
315    			LogMsg("WARNING: mdnsd continuing as root because user \""MDNSD_USER"\" does not exist");
316#endif
317		}
318
319	if (mStatus_NoError == err)
320		err = MainLoop(&mDNSStorage);
321
322	LogMsg("%s stopping", mDNSResponderVersionString);
323
324	mDNS_Close(&mDNSStorage);
325
326	if (udsserver_exit() < 0)
327		LogMsg("ExitCallback: udsserver_exit failed");
328
329 #if MDNS_DEBUGMSGS > 0
330	printf("mDNSResponder exiting normally with %ld\n", err);
331 #endif
332
333	return err;
334	}
335
336//		uds_daemon support		////////////////////////////////////////////////////////////
337
338mStatus udsSupportAddFDToEventLoop(int fd, udsEventCallback callback, void *context)
339/* Support routine for uds_daemon.c */
340	{
341	// Depends on the fact that udsEventCallback == mDNSPosixEventCallback
342	return mDNSPosixAddFDToEventLoop(fd, callback, context);
343	}
344
345mStatus udsSupportRemoveFDFromEventLoop(int fd)		// Note: This also CLOSES the file descriptor
346	{
347	mStatus err = mDNSPosixRemoveFDFromEventLoop(fd);
348	close(fd);
349	return err;
350	}
351
352mDNSexport void RecordUpdatedNiceLabel(mDNS *const m, mDNSs32 delay)
353	{
354	(void)m;
355	(void)delay;
356	// No-op, for now
357	}
358
359#if _BUILDING_XCODE_PROJECT_
360// If the process crashes, then this string will be magically included in the automatically-generated crash log
361const char *__crashreporter_info__ = mDNSResponderVersionString_SCCS + 5;
362asm(".desc ___crashreporter_info__, 0x10");
363#endif
364
365// For convenience when using the "strings" command, this is the last thing in the file
366#if mDNSResponderVersion > 1
367mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder-" STRINGIFY(mDNSResponderVersion);
368#elif MDNS_VERSIONSTR_NODTS
369mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder (Engineering Build)";
370#else
371mDNSexport const char mDNSResponderVersionString_SCCS[] = "@(#) mDNSResponder (Engineering Build)";
372#endif
373