mDNSMacOSX/helper-main.c

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2007 Apple 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     Change History (most recent first):
  18
  19 $Log: helper-main.c,v $
  20 Revision 1.15  2008/03/13 20:55:16  mcguire
  21 <rdar://problem/5769316> fix deprecated warnings/errors
  22 Additional cleanup: use a conditional macro instead of lots of #if
  23
  24 Revision 1.14  2008/03/12 23:02:59  mcguire
  25 <rdar://problem/5769316> fix deprecated warnings/errors
  26
  27 Revision 1.13  2007/09/21 16:13:14  cheshire
  28 Additional Tiger compatibility fix: After bootstrap_check_in, we need to give
  29 ourselves a Mach "send" right to the port, otherwise our ten-second idle timeout
  30 mechanism is not able to send the "mDNSIdleExit" message to itself
  31
  32 Revision 1.12  2007/09/20 22:26:20  cheshire
  33 Add necessary bootstrap_check_in() in Tiger compatibility code (not used on Leopard)
  34
  35 Revision 1.11  2007/09/18 19:09:02  cheshire
  36 <rdar://problem/5489549> mDNSResponderHelper (and other binaries) missing SCCS version strings
  37
  38 Revision 1.10  2007/09/09 02:21:17  mcguire
  39 <rdar://problem/5469345> Leopard Server9A547(Insatll):mDNSResponderHelper crashing
  40
  41 Revision 1.9  2007/09/07 22:44:03  mcguire
  42 <rdar://problem/5448420> Move CFUserNotification code to mDNSResponderHelper
  43
  44 Revision 1.8  2007/09/07 22:24:36  vazquez
  45 <rdar://problem/5466301> Need to stop spewing mDNSResponderHelper logs
  46
  47 Revision 1.7  2007/08/31 18:09:32  cheshire
  48 <rdar://problem/5434050> Restore ability to run mDNSResponder on Tiger
  49
  50 Revision 1.6  2007/08/31 17:45:13  cheshire
  51 Allow maxidle time of zero, meaning "run indefinitely"
  52
  53 Revision 1.5  2007/08/31 00:09:54  cheshire
  54 Deleted extraneous whitespace (shortened code from 260 lines to 160)
  55
  56 Revision 1.4  2007/08/28 00:33:04  jgraessley
  57 <rdar://problem/5423932> Selective compilation options
  58
  59 Revision 1.3  2007/08/23 23:21:24  cheshire
  60 Tiger compatibility: Use old bootstrap_register() instead of Leopard-only bootstrap_register2()
  61
  62 Revision 1.2  2007/08/23 21:36:17  cheshire
  63 Made code layout style consistent with existing project style; added $Log header
  64
  65 Revision 1.1  2007/08/08 22:34:58  mcguire
  66 <rdar://problem/5197869> Security: Run mDNSResponder as user id mdnsresponder instead of root
  67  */
  68
  69 #define _FORTIFY_SOURCE 2
  70 #include <CoreFoundation/CoreFoundation.h>
  71 #include <sys/cdefs.h>
  72 #include <sys/time.h>
  73 #include <sys/types.h>
  74 #include <mach/mach.h>
  75 #include <mach/mach_error.h>
  76 #include <servers/bootstrap.h>
  77 #include <asl.h>
  78 #include <launch.h>
  79 #include <pwd.h>
  80 #include <pthread.h>
  81 #include <stdarg.h>
  82 #include <stdbool.h>
  83 #include <stdio.h>
  84 #include <stdlib.h>
  85 #include <time.h>
  86 #include <unistd.h>
  87 #include <Security/Security.h>
  88 #include "helper.h"
  89 #include "helper-server.h"
  90 #include "helpermsg.h"
  91 #include "helpermsgServer.h"
  92
  93 #if TARGET_OS_EMBEDDED
  94 #include <bootstrap_priv.h>
  95 #define NO_SECURITYFRAMEWORK 1
  96
  97 #define bootstrap_register(A,B,C) bootstrap_register2((A),(B),(C),0)
  98 #endif
  99
 100 #ifndef LAUNCH_JOBKEY_MACHSERVICES
 101 #define LAUNCH_JOBKEY_MACHSERVICES "MachServices"
 102 #define LAUNCH_DATA_MACHPORT 10
 103 #define launch_data_get_machport launch_data_get_fd
 104 #endif
 105
 106 union max_msg_size
 107         {
 108         union __RequestUnion__proxy_helper_subsystem req;
 109         union __ReplyUnion__proxy_helper_subsystem rep;
 110         };
 111
 112 static const mach_msg_size_t MAX_MSG_SIZE = sizeof(union max_msg_size) + MAX_TRAILER_SIZE;
 113 static aslclient logclient = NULL;
 114 static int opt_debug;
 115 static pthread_t idletimer_thread;
 116
 117 unsigned long maxidle = 10;
 118 unsigned long actualidle = 3600;
 119
 120 CFRunLoopRef gRunLoop = NULL;
 121 CFRunLoopTimerRef gTimer = NULL;
 122
 123 static void helplogv(int level, const char *fmt, va_list ap)
 124         {
 125         if (NULL == logclient) { vfprintf(stderr, fmt, ap); fflush(stderr); }
 126         else asl_vlog(logclient, NULL, level, fmt, ap);
 127         }
 128
 129 void helplog(int level, const char *fmt, ...)
 130         {
 131         va_list ap;
 132         va_start(ap, fmt);
 133         helplogv(level, fmt, ap);
 134         va_end(ap);
 135         }
 136
 137 static void initialize_logging(void)
 138         {
 139         logclient = asl_open(NULL, kmDNSHelperServiceName, (opt_debug ? ASL_OPT_STDERR : 0));
 140         if (NULL == logclient) { fprintf(stderr, "Could not initialize ASL logging.\n"); fflush(stderr); return; }
 141         if (opt_debug) asl_set_filter(logclient, ASL_FILTER_MASK_UPTO(ASL_LEVEL_DEBUG));
 142         }
 143
 144 static void initialize_id(void)
 145         {
 146         static char login[] = "_mdnsresponder";
 147         struct passwd *pwd = getpwnam(login);
 148
 149         if (!pwd) { helplog(ASL_LEVEL_ERR, "Could not find account name `%s'.  I will only help root.", login); return; }
 150         mDNSResponderUID = pwd->pw_uid;
 151         mDNSResponderGID = pwd->pw_gid;
 152         }
 153
 154 static void diediedie(CFRunLoopTimerRef timer, void *context)
 155         {
 156         debug("entry");
 157         assert(gTimer == timer);
 158         if (maxidle)
 159           (void)proxy_mDNSIdleExit((mach_port_t)context);
 160         }
 161
 162 void pause_idle_timer(void)
 163         {
 164         debug("entry");
 165         assert(gTimer);
 166         assert(gRunLoop);
 167         CFRunLoopRemoveTimer(gRunLoop, gTimer, kCFRunLoopDefaultMode);
 168         }
 169
 170 void unpause_idle_timer(void)
 171         {
 172         debug("entry");
 173         assert(gRunLoop);
 174         assert(gTimer);
 175         CFRunLoopAddTimer(gRunLoop, gTimer, kCFRunLoopDefaultMode);
 176         }
 177
 178 void update_idle_timer(void)
 179         {
 180         debug("entry");
 181         assert(gTimer);
 182         CFRunLoopTimerSetNextFireDate(gTimer, CFAbsoluteTimeGetCurrent() + actualidle);
 183         }
 184
 185 static void *idletimer(void *context)
 186         {
 187         debug("entry context=%p", context);
 188         gRunLoop = CFRunLoopGetCurrent();
 189
 190         unpause_idle_timer();
 191
 192         for (;;)
 193                 {
 194                 debug("Running CFRunLoop");
 195                 CFRunLoopRun();
 196                 sleep(1);
 197                 }
 198
 199         return NULL;
 200         }
 201
 202 static void initialize_timer(mach_port_t port)
 203         {
 204         CFRunLoopTimerContext cxt = {0, (void *)port, NULL, NULL, NULL};
 205         gTimer = CFRunLoopTimerCreate(kCFAllocatorDefault, CFAbsoluteTimeGetCurrent() + actualidle, actualidle, 0, 0, diediedie, &cxt);
 206         int err = 0;
 207
 208         debug("entry port=%p", port);
 209         if (0 != (err = pthread_create(&idletimer_thread, NULL, idletimer, (void *)port)))
 210                 helplog(ASL_LEVEL_ERR, "Could not start idletimer thread: %s", strerror(err));
 211         }
 212
 213 static mach_port_t checkin(char *service_name)
 214         {
 215         kern_return_t kr = KERN_SUCCESS;
 216         mach_port_t port = MACH_PORT_NULL;
 217         launch_data_t msg = NULL, reply = NULL, datum = NULL;
 218
 219         if (NULL == (msg = launch_data_new_string(LAUNCH_KEY_CHECKIN)))
 220                 { helplog(ASL_LEVEL_ERR, "Could not create checkin message for launchd."); goto fin; }
 221         if (NULL == (reply = launch_msg(msg)))
 222                 { helplog(ASL_LEVEL_ERR, "Could not message launchd."); goto fin; }
 223         if (LAUNCH_DATA_ERRNO == launch_data_get_type(reply))
 224                 {
 225                 if (launch_data_get_errno(reply) == EACCES) { launch_data_free(msg); launch_data_free(reply); return(MACH_PORT_NULL); }
 226                 helplog(ASL_LEVEL_ERR, "Launchd checkin failed: %s.", strerror(launch_data_get_errno(reply))); goto fin;
 227                 }
 228         if (NULL == (datum = launch_data_dict_lookup(reply, LAUNCH_JOBKEY_MACHSERVICES)) || LAUNCH_DATA_DICTIONARY != launch_data_get_type(datum))
 229                 { helplog(ASL_LEVEL_ERR, "Launchd reply does not contain %s dictionary.", LAUNCH_JOBKEY_MACHSERVICES); goto fin; }
 230         if (NULL == (datum = launch_data_dict_lookup(datum, service_name)) || LAUNCH_DATA_MACHPORT != launch_data_get_type(datum))
 231                 { helplog(ASL_LEVEL_ERR, "Launchd reply does not contain %s Mach port.", service_name); goto fin; }
 232         if (MACH_PORT_NULL == (port = launch_data_get_machport(datum)))
 233                 { helplog(ASL_LEVEL_ERR, "Launchd gave me a null Mach port."); goto fin; }
 234         if (KERN_SUCCESS != (kr = mach_port_insert_right(mach_task_self(), port, port, MACH_MSG_TYPE_MAKE_SEND)))
 235                 { helplog(ASL_LEVEL_ERR, "mach_port_insert_right: %s", mach_error_string(kr)); goto fin; }
 236
 237 fin:
 238         if (NULL != msg)   launch_data_free(msg);
 239         if (NULL != reply) launch_data_free(reply);
 240         if (MACH_PORT_NULL == port) exit(EXIT_FAILURE);
 241         return port;
 242         }
 243
 244 static mach_port_t register_service(const char *service_name)
 245         {
 246         mach_port_t port = MACH_PORT_NULL;
 247         kern_return_t kr;
 248
 249         if (KERN_SUCCESS == (kr = bootstrap_check_in(bootstrap_port, (char *)service_name, &port)))
 250                 {
 251                 if (KERN_SUCCESS != (kr = mach_port_insert_right(mach_task_self(), port, port, MACH_MSG_TYPE_MAKE_SEND)))
 252                         helplog(ASL_LEVEL_ERR, "mach_port_insert_right: %s", mach_error_string(kr));
 253                 else
 254                         return port;
 255                 }
 256         if (KERN_SUCCESS != (kr = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &port)))
 257                 { helplog(ASL_LEVEL_ERR, "mach_port_allocate: %s", mach_error_string(kr)); goto error; }
 258         if (KERN_SUCCESS != (kr = mach_port_insert_right(mach_task_self(), port, port, MACH_MSG_TYPE_MAKE_SEND)))
 259                 { helplog(ASL_LEVEL_ERR, "mach_port_insert_right: %s", mach_error_string(kr)); goto error; }
 260
 261         // XXX bootstrap_register does not modify its second argument, but the prototype does not include const.
 262         if (KERN_SUCCESS != (kr = bootstrap_register(bootstrap_port, (char *)service_name, port)))
 263                 { helplog(ASL_LEVEL_ERR, "bootstrap_register failed: %s", mach_error_string(kr)); goto error; }
 264
 265         return port;
 266 error:
 267         if (MACH_PORT_NULL != port) mach_port_deallocate(mach_task_self(), port);
 268         return MACH_PORT_NULL;
 269         }
 270
 271 int main(int ac, char *av[])
 272         {
 273         char *p = NULL;
 274         kern_return_t kr = KERN_FAILURE;
 275         mach_port_t port = MACH_PORT_NULL;
 276         long n;
 277         int ch;
 278
 279         while ((ch = getopt(ac, av, "dt:")) != -1)
 280                 switch (ch)
 281                 {
 282                 case 'd': opt_debug = 1; break;
 283                 case 't':
 284                         n = strtol(optarg, &p, 0);
 285                         if ('\0' == optarg[0] || '\0' != *p || n > LONG_MAX || n < 0)
 286                                 { fprintf(stderr, "Invalid idle timeout: %s\n", optarg); exit(EXIT_FAILURE); }
 287                         maxidle = n;
 288                         break;
 289                 case '?':
 290                 default:
 291                         fprintf(stderr, "Usage: mDNSResponderHelper [-d] [-t maxidle]\n");
 292                         exit(EXIT_FAILURE);
 293                 }
 294         ac -= optind;
 295         av += optind;
 296
 297         initialize_logging();
 298         helplog(ASL_LEVEL_INFO, "Starting");
 299         initialize_id();
 300
 301 #ifndef NO_SECURITYFRAMEWORK
 302         // We should normally be running as a system daemon.  However, that might not be the case in some scenarios (e.g. debugging).
 303         // Explicitly ensure that our Keychain operations utilize the system domain.
 304         SecKeychainSetPreferenceDomain(kSecPreferencesDomainSystem);
 305 #endif
 306         port = checkin(kmDNSHelperServiceName);
 307         if (!port)
 308                 {
 309                 helplog(ASL_LEVEL_ERR, "Launchd provided no launchdata; will open Mach port explicitly");
 310                 port = register_service(kmDNSHelperServiceName);
 311                 }
 312
 313         if (maxidle) actualidle = maxidle;
 314         initialize_timer(port);
 315
 316         kr = mach_msg_server(helper_server, MAX_MSG_SIZE, port,
 317                 MACH_RCV_TRAILER_ELEMENTS(MACH_RCV_TRAILER_AUDIT) | MACH_RCV_TRAILER_TYPE(MACH_MSG_TRAILER_FORMAT_0));
 318         if (KERN_SUCCESS != kr)
 319                 { helplog(ASL_LEVEL_ERR, "mach_msg_server: %s\n", mach_error_string(kr)); exit(EXIT_FAILURE); }
 320         exit(EXIT_SUCCESS);
 321         }
 322
 323 // Note: The C preprocessor stringify operator ('#') makes a string from its argument, without macro expansion
 324 // e.g. If "version" is #define'd to be "4", then STRINGIFY_AWE(version) will return the string "version", not "4"
 325 // To expand "version" to its value before making the string, use STRINGIFY(version) instead
 326 #define STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s) #s
 327 #define STRINGIFY(s) STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s)
 328
 329 // For convenience when using the "strings" command, this is the last thing in the file
 330 // The "@(#) " pattern is a special prefix the "what" command looks for
 331 const char VersionString_SCCS[] = "@(#) mDNSResponderHelper " STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ")";
 332
 333 // If the process crashes, then this string will be magically included in the automatically-generated crash log
 334 const char *__crashreporter_info__ = VersionString_SCCS + 5;
 335 asm(".desc ___crashreporter_info__, 0x10");