PosixDaemon.c revision 4b22b9337f359bfd063322244f5336cc7c6ffcfa
/* -*- Mode: C; tab-width: 4 -*-
*
* Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
File: daemon.c
Contains: main & associated Application layer for mDNSResponder on Linux.
Change History (most recent first):
$Log: PosixDaemon.c,v $
Revision 1.29.2.1 2006/08/29 06:24:34 cheshire
Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0
Revision 1.29 2005/08/04 03:37:45 mkrochma
Temporary workaround to fix posix after mDNS_SetPrimaryInterfaceInfo changed
Revision 1.28 2005/07/19 11:21:09 cheshire
<rdar://problem/4170449> Unix Domain Socket leak in mdnsd
Revision 1.27 2005/02/04 00:39:59 cheshire
Move ParseDNSServers() from PosixDaemon.c to mDNSPosix.c so all Posix client layers can use it
Revision 1.26 2005/02/02 02:21:30 cheshire
Update references to "mDNSResponder" to say "mdnsd" instead
Revision 1.25 2005/01/27 20:01:50 cheshire
udsSupportRemoveFDFromEventLoop() needs to close the file descriptor as well
Revision 1.24 2005/01/19 19:20:49 ksekar
<rdar://problem/3960191> Need a way to turn off domain discovery
Revision 1.23 2004/12/16 20:17:11 cheshire
<rdar://problem/3324626> Cache memory management improvements
Revision 1.22 2004/12/10 13:12:08 cheshire
Create no-op function RecordUpdatedNiceLabel(), required by uds_daemon.c
Revision 1.21 2004/12/01 20:57:20 ksekar
<rdar://problem/3873921> Wide Area Service Discovery must be split-DNS aware
Revision 1.20 2004/12/01 04:28:43 cheshire
<rdar://problem/3872803> Darwin patches for Solaris and Suse
Use version of daemon() provided in mDNSUNP.c instead of local copy
Revision 1.19 2004/12/01 03:30:29 cheshire
<rdar://problem/3889346> Add Unicast DNS support to mDNSPosix
Revision 1.18 2004/11/30 22:45:59 cheshire
Minor code tidying
Revision 1.17 2004/11/30 22:18:59 cheshire
<rdar://problem/3889351> Posix needs to read the list of unicast DNS servers and set server list
Revision 1.16 2004/09/21 21:05:12 cheshire
Move duplicate code out of mDNSMacOSX/daemon.c and mDNSPosix/PosixDaemon.c,
into mDNSShared/uds_daemon.c
Revision 1.15 2004/09/17 01:08:53 cheshire
Renamed mDNSClientAPI.h to mDNSEmbeddedAPI.h
The name "mDNSClientAPI.h" is misleading to new developers looking at this code. The interfaces
declared in that file are ONLY appropriate to single-address-space embedded applications.
For clients on general-purpose computers, the interfaces defined in dns_sd.h should be used.
Revision 1.14 2004/09/16 00:24:49 cheshire
<rdar://problem/3803162> Fix unsafe use of mDNSPlatformTimeNow()
Revision 1.13 2004/08/11 01:59:41 cheshire
Remove "mDNS *globalInstance" parameter from udsserver_init()
Revision 1.12 2004/06/28 23:19:19 cheshire
Fix "Daemon_Init declared but never defined" warning on Linux
Revision 1.11 2004/06/25 00:26:27 rpantos
Changes to fix the Posix build on Solaris.
Revision 1.10 2004/06/08 04:59:40 cheshire
Tidy up wording -- log messages are already prefixed with "mDNSResponder", so don't need to repeat it
Revision 1.9 2004/05/29 00:14:20 rpantos
<rdar://problem/3508093> Runtime check to disable prod mdnsd on OS X.
Revision 1.8 2004/04/07 01:19:04 cheshire
Hash slot value should be unsigned
Revision 1.7 2004/02/14 06:34:57 cheshire
Use LogMsg instead of fprintf( stderr
Revision 1.6 2004/02/14 01:10:42 rpantos
Allow daemon to run if 'nobody' is not defined, with a warning. (For Roku HD1000.)
Revision 1.5 2004/02/05 07:45:43 cheshire
Add Log header
Revision 1.4 2004/01/28 21:14:23 cheshire
Reconcile debug_mode and gDebugLogging into a single flag (mDNS_DebugMode)
Revision 1.3 2004/01/19 19:51:46 cheshire
Fix compiler error (mixed declarations and code) on some versions of Linux
Revision 1.2 2003/12/11 03:03:51 rpantos
Clean up mDNSPosix so that it builds on OS X again.
Revision 1.1 2003/12/08 20:47:02 rpantos
Add support for mDNSResponder on Linux.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <sys/types.h>
#include "mDNSEmbeddedAPI.h"
#include "mDNSDebug.h"
#include "mDNSPosix.h"
#include "uds_daemon.h"
#include "PlatformCommon.h"
#include "mDNSUNP.h"
#ifndef MDNSD_USER
#define MDNSD_USER "nobody"
#endif
#define CONFIG_FILE "/etc/mdnsd.conf"
static domainname DynDNSZone; // Default wide-area zone for service registration
static domainname DynDNSHostname;
#define RR_CACHE_SIZE 500
static CacheEntity gRRCache[RR_CACHE_SIZE];
extern const char mDNSResponderVersionString[];
static void Reconfigure(mDNS *m)
{
mDNSAddr DynDNSIP;
mDNS_SetPrimaryInterfaceInfo(m, NULL, NULL, NULL);
mDNS_DeleteDNSServers(m);
if (ParseDNSServers(m, uDNS_SERVERS_FILE) < 0)
LogMsg("Unable to parse DNS server list. Unicast DNS-SD unavailable");
ReadDDNSSettingsFromConfFile(m, CONFIG_FILE, &DynDNSHostname, &DynDNSZone, NULL);
FindDefaultRouteIP(&DynDNSIP);
if (DynDNSHostname.c[0]) mDNS_AddDynDNSHostName(m, &DynDNSHostname, NULL, NULL);
if (DynDNSIP.type) mDNS_SetPrimaryInterfaceInfo(m, &DynDNSIP, NULL, NULL);
}
// Do appropriate things at startup with command line arguments. Calls exit() if unhappy.
static void ParseCmdLinArgs(int argc, char **argv)
{
if (argc > 1)
{
if (0 == strcmp(argv[1], "-debug")) mDNS_DebugMode = mDNStrue;
else printf("Usage: %s [-debug]\n", argv[0]);
}
if (!mDNS_DebugMode)
{
int result = daemon(0, 0);
if (result != 0) { LogMsg("Could not run as daemon - exiting"); exit(result); }
#if __APPLE__
LogMsg("The POSIX mdnsd should only be used on OS X for testing - exiting");
exit(-1);
#endif
}
}
static void DumpStateLog(mDNS *const m)
// Dump a little log of what we've been up to.
{
LogMsgIdent(mDNSResponderVersionString, "---- BEGIN STATE LOG ----");
udsserver_info(m);
LogMsgIdent(mDNSResponderVersionString, "---- END STATE LOG ----");
}
static mStatus MainLoop(mDNS *m) // Loop until we quit.
{
sigset_t signals;
mDNSBool gotData = mDNSfalse;
mDNSPosixListenForSignalInEventLoop(SIGINT);
mDNSPosixListenForSignalInEventLoop(SIGTERM);
mDNSPosixListenForSignalInEventLoop(SIGUSR1);
mDNSPosixListenForSignalInEventLoop(SIGPIPE);
mDNSPosixListenForSignalInEventLoop(SIGHUP) ;
for (; ;)
{
// Work out how long we expect to sleep before the next scheduled task
struct timeval timeout;
mDNSs32 ticks;
// Only idle if we didn't find any data the last time around
if (!gotData)
{
mDNSs32 nextTimerEvent = mDNS_Execute(m);
nextTimerEvent = udsserver_idle(nextTimerEvent);
ticks = nextTimerEvent - mDNS_TimeNow(m);
if (ticks < 1) ticks = 1;
}
else // otherwise call EventLoop again with 0 timemout
ticks = 0;
timeout.tv_sec = ticks / mDNSPlatformOneSecond;
timeout.tv_usec = (ticks % mDNSPlatformOneSecond) * 1000000 / mDNSPlatformOneSecond;
(void) mDNSPosixRunEventLoopOnce(m, &timeout, &signals, &gotData);
if (sigismember(&signals, SIGHUP )) Reconfigure(m);
if (sigismember(&signals, SIGUSR1)) DumpStateLog(m);
// SIGPIPE happens when we try to write to a dead client; death should be detected soon in request_callback() and cleaned up.
if (sigismember(&signals, SIGPIPE)) LogMsg("Received SIGPIPE - ignoring");
if (sigismember(&signals, SIGINT) || sigismember(&signals, SIGTERM)) break;
}
return EINTR;
}
int main(int argc, char **argv)
{
#define mDNSRecord mDNSStorage
mDNS_PlatformSupport platformStorage;
mStatus err;
bzero(&mDNSRecord, sizeof mDNSRecord);
bzero(&platformStorage, sizeof platformStorage);
ParseCmdLinArgs(argc, argv);
LogMsgIdent(mDNSResponderVersionString, "starting");
err = mDNS_Init(&mDNSRecord, &platformStorage, gRRCache, RR_CACHE_SIZE, mDNS_Init_AdvertiseLocalAddresses,
mDNS_Init_NoInitCallback, mDNS_Init_NoInitCallbackContext);
if (mStatus_NoError == err)
err = udsserver_init();
Reconfigure(&mDNSRecord);
// Now that we're finished with anything privileged, switch over to running as "nobody"
if (mStatus_NoError == err)
{
const struct passwd *pw = getpwnam(MDNSD_USER);
if (pw != NULL)
setuid(pw->pw_uid);
else
#ifdef MDNSD_NOROOT
{
LogMsg("WARNING: mdnsd exiting because user \""MDNSD_USER"\" does not exist");
err = mStatus_Invalid;
}
#else
LogMsg("WARNING: mdnsd continuing as root because user \""MDNSD_USER"\" does not exist");
#endif
}
if (mStatus_NoError == err)
err = MainLoop(&mDNSRecord);
LogMsgIdent(mDNSResponderVersionString, "stopping");
mDNS_Close(&mDNSRecord);
if (udsserver_exit() < 0)
LogMsg("ExitCallback: udsserver_exit failed");
#if MDNS_DEBUGMSGS > 0
printf("mDNSResponder exiting normally with %ld\n", err);
#endif
return err;
}
// uds_daemon support ////////////////////////////////////////////////////////////
#undef LogMalloc
#if MDNS_MALLOC_DEBUGGING >= 2
#define LogMalloc LogMsg
#else
#define LogMalloc(ARGS...) ((void)0)
#endif
mStatus udsSupportAddFDToEventLoop(int fd, udsEventCallback callback, void *context)
/* Support routine for uds_daemon.c */
{
// Depends on the fact that udsEventCallback == mDNSPosixEventCallback
return mDNSPosixAddFDToEventLoop(fd, callback, context);
}
mStatus udsSupportRemoveFDFromEventLoop(int fd) // Note: This also CLOSES the file descriptor
{
mStatus err = mDNSPosixRemoveFDFromEventLoop(fd);
close(fd);
return err;
}
mDNSexport void RecordUpdatedNiceLabel(mDNS *const m, mDNSs32 delay)
{
(void)m;
(void)delay;
// No-op, for now
}
#if MACOSX_MDNS_MALLOC_DEBUGGING >= 1
void *mallocL(char *msg, unsigned int size)
{
unsigned long *mem = malloc(size+8);
if (!mem)
{
LogMsg("malloc( %s : %d ) failed", msg, size);
return(NULL);
}
else
{
LogMalloc("malloc( %s : %lu ) = %p", msg, size, &mem[2]);
mem[0] = 0xDEAD1234;
mem[1] = size;
//bzero(&mem[2], size);
memset(&mem[2], 0xFF, size);
// validatelists(&mDNSStorage);
return(&mem[2]);
}
}
void freeL(char *msg, void *x)
{
if (!x)
LogMsg("free( %s @ NULL )!", msg);
else
{
unsigned long *mem = ((unsigned long *)x) - 2;
if (mem[0] != 0xDEAD1234)
{ LogMsg("free( %s @ %p ) !!!! NOT ALLOCATED !!!!", msg, &mem[2]); return; }
if (mem[1] > 8000)
{ LogMsg("free( %s : %ld @ %p) too big!", msg, mem[1], &mem[2]); return; }
LogMalloc("free( %s : %ld @ %p)", msg, mem[1], &mem[2]);
//bzero(mem, mem[1]+8);
memset(mem, 0xDD, mem[1]+8);
// validatelists(&mDNSStorage);
free(mem);
}
}
#endif // MACOSX_MDNS_MALLOC_DEBUGGING >= 1
// For convenience when using the "strings" command, this is the last thing in the file
#if mDNSResponderVersion > 1
mDNSexport const char mDNSResponderVersionString[] = "mDNSResponder-" STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ") ";
#else
mDNSexport const char mDNSResponderVersionString[] = "mDNSResponder (Engineering Build) (" __DATE__ " " __TIME__ ") ";
#endif