/* -*- Mode: C; tab-width: 4 -*-
*
* Copyright (c) 2007 Apple 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.
*/
#define _FORTIFY_SOURCE 2
#include <CoreFoundation/CoreFoundation.h>
#include <sys/cdefs.h>
#include <sys/time.h>
#include <sys/types.h>
#include <mach/mach.h>
#include <mach/mach_error.h>
#include <servers/bootstrap.h>
#include <asl.h>
#include <launch.h>
#include <pwd.h>
#include <pthread.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <Security/Security.h>
#include "helper.h"
#include "helper-server.h"
#include "helpermsg.h"
#include "helpermsgServer.h"
#include <vproc.h>
#if TARGET_OS_EMBEDDED
#define NO_SECURITYFRAMEWORK 1
#endif
#ifndef LAUNCH_JOBKEY_MACHSERVICES
#define LAUNCH_JOBKEY_MACHSERVICES "MachServices"
#define LAUNCH_DATA_MACHPORT 10
#define launch_data_get_machport launch_data_get_fd
#endif
union max_msg_size
{
union __RequestUnion__proxy_helper_subsystem req;
union __ReplyUnion__proxy_helper_subsystem rep;
};
static const mach_msg_size_t MAX_MSG_SIZE = sizeof(union max_msg_size) + MAX_TRAILER_SIZE;
static aslclient logclient = NULL;
static int opt_debug;
static pthread_t idletimer_thread;
unsigned long maxidle = 15;
unsigned long actualidle = 3600;
CFRunLoopRef gRunLoop = NULL;
CFRunLoopTimerRef gTimer = NULL;
mach_port_t gPort = MACH_PORT_NULL;
static void helplogv(int level, const char *fmt, va_list ap)
{
if (NULL == logclient) { vfprintf(stderr, fmt, ap); fflush(stderr); }
else asl_vlog(logclient, NULL, level, fmt, ap);
}
void helplog(int level, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
helplogv(level, fmt, ap);
va_end(ap);
}
// for safe_vproc
void LogMsgWithLevel(mDNSLogLevel_t logLevel, const char *fmt, ...)
{
(void)logLevel;
va_list ap;
va_start(ap, fmt);
// safe_vproc only calls LogMsg, so assume logLevel maps to ASL_LEVEL_ERR
helplog(ASL_LEVEL_ERR, fmt, ap);
va_end(ap);
}
static void handle_sigterm(int sig)
{
// debug("entry sig=%d", sig); Can't use syslog from within a signal handler
assert(sig == SIGTERM);
(void)proxy_mDNSExit(gPort);
}
static void initialize_logging(void)
{
logclient = asl_open(NULL, kmDNSHelperServiceName, (opt_debug ? ASL_OPT_STDERR : 0));
if (NULL == logclient) { fprintf(stderr, "Could not initialize ASL logging.\n"); fflush(stderr); return; }
if (opt_debug) asl_set_filter(logclient, ASL_FILTER_MASK_UPTO(ASL_LEVEL_DEBUG));
}
static void initialize_id(void)
{
static char login[] = "_mdnsresponder";
struct passwd hardcode;
struct passwd *pwd = &hardcode; // getpwnam(login);
hardcode.pw_uid = 65;
hardcode.pw_gid = 65;
if (!pwd) { helplog(ASL_LEVEL_ERR, "Could not find account name `%s'. I will only help root.", login); return; }
mDNSResponderUID = pwd->pw_uid;
mDNSResponderGID = pwd->pw_gid;
}
static void diediedie(CFRunLoopTimerRef timer, void *context)
{
debug("entry %p %p %d", timer, context, maxidle);
assert(gTimer == timer);
if (maxidle)
(void)proxy_mDNSExit(gPort);
}
void pause_idle_timer(void)
{
debug("entry");
assert(gTimer);
assert(gRunLoop);
CFRunLoopRemoveTimer(gRunLoop, gTimer, kCFRunLoopDefaultMode);
}
void unpause_idle_timer(void)
{
debug("entry");
assert(gRunLoop);
assert(gTimer);
CFRunLoopAddTimer(gRunLoop, gTimer, kCFRunLoopDefaultMode);
}
void update_idle_timer(void)
{
debug("entry");
assert(gTimer);
CFRunLoopTimerSetNextFireDate(gTimer, CFAbsoluteTimeGetCurrent() + actualidle);
}
static void *idletimer(void *context)
{
debug("entry context=%p", context);
gRunLoop = CFRunLoopGetCurrent();
unpause_idle_timer();
for (;;)
{
debug("Running CFRunLoop");
CFRunLoopRun();
sleep(1);
}
return NULL;
}
static int initialize_timer()
{
gTimer = CFRunLoopTimerCreate(kCFAllocatorDefault, CFAbsoluteTimeGetCurrent() + actualidle, actualidle, 0, 0, diediedie, NULL);
int err = 0;
debug("entry");
if (0 != (err = pthread_create(&idletimer_thread, NULL, idletimer, NULL)))
helplog(ASL_LEVEL_ERR, "Could not start idletimer thread: %s", strerror(err));
return err;
}
static mach_port_t register_service(const char *service_name)
{
mach_port_t port = MACH_PORT_NULL;
kern_return_t kr;
if (KERN_SUCCESS != (kr = bootstrap_check_in(bootstrap_port, (char *)service_name, &port)))
{
helplog(ASL_LEVEL_ERR, "bootstrap_check_in: %d %X %s", kr, kr, mach_error_string(kr));
return MACH_PORT_NULL;
}
if (KERN_SUCCESS != (kr = mach_port_insert_right(mach_task_self(), port, port, MACH_MSG_TYPE_MAKE_SEND)))
{
helplog(ASL_LEVEL_ERR, "mach_port_insert_right: %d %X %s", kr, kr, mach_error_string(kr));
mach_port_deallocate(mach_task_self(), port);
return MACH_PORT_NULL;
}
return port;
}
int main(int ac, char *av[])
{
char *p = NULL;
kern_return_t kr = KERN_FAILURE;
long n;
int ch;
mach_msg_header_t hdr;
while ((ch = getopt(ac, av, "dt:")) != -1)
switch (ch)
{
case 'd': opt_debug = 1; break;
case 't':
n = strtol(optarg, &p, 0);
if ('\0' == optarg[0] || '\0' != *p || n > LONG_MAX || n < 0)
{ fprintf(stderr, "Invalid idle timeout: %s\n", optarg); exit(EXIT_FAILURE); }
maxidle = n;
break;
case '?':
default:
fprintf(stderr, "Usage: mDNSResponderHelper [-d] [-t maxidle]\n");
exit(EXIT_FAILURE);
}
ac -= optind;
av += optind;
initialize_logging();
helplog(ASL_LEVEL_INFO, "Starting");
initialize_id();
#ifndef NO_SECURITYFRAMEWORK
// We should normally be running as a system daemon. However, that might not be the case in some scenarios (e.g. debugging).
// Explicitly ensure that our Keychain operations utilize the system domain.
if (opt_debug) SecKeychainSetPreferenceDomain(kSecPreferencesDomainSystem);
#endif
gPort = register_service(kmDNSHelperServiceName);
if (!gPort)
exit(EXIT_FAILURE);
if (maxidle) actualidle = maxidle;
signal(SIGTERM, handle_sigterm);
// We use BeginTransactionAtShutdown in the plist that ensures that we will
// receive a SIGTERM during shutdown rather than a SIGKILL. But launchd (due to some
// limitation) currently requires us to still start and end the transaction for
// its proper initialization.
vproc_transaction_t vt = vproc_transaction_begin(NULL);
if (vt) vproc_transaction_end(NULL, vt);
if (initialize_timer()) exit(EXIT_FAILURE);
for (n=0; n<100000; n++) if (!gRunLoop) usleep(100);
if (!gRunLoop)
{
helplog(ASL_LEVEL_ERR, "gRunLoop not set after waiting");
exit(EXIT_FAILURE);
}
for(;;)
{
hdr.msgh_bits = 0;
hdr.msgh_local_port = gPort;
hdr.msgh_remote_port = MACH_PORT_NULL;
hdr.msgh_size = sizeof(hdr);
hdr.msgh_id = 0;
kr = mach_msg(&hdr, MACH_RCV_LARGE | MACH_RCV_MSG, 0, hdr.msgh_size, gPort, 0, 0);
if (MACH_RCV_TOO_LARGE != kr)
helplog(ASL_LEVEL_ERR, "main MACH_RCV_MSG error: %d %X %s", kr, kr, mach_error_string(kr));
kr = mach_msg_server_once(helper_server, MAX_MSG_SIZE, gPort,
MACH_RCV_TRAILER_ELEMENTS(MACH_RCV_TRAILER_AUDIT) | MACH_RCV_TRAILER_TYPE(MACH_MSG_TRAILER_FORMAT_0));
if (KERN_SUCCESS != kr)
{ helplog(ASL_LEVEL_ERR, "mach_msg_server: %d %X %s", kr, kr, mach_error_string(kr)); exit(EXIT_FAILURE); }
}
exit(EXIT_SUCCESS);
}
// Note: The C preprocessor stringify operator ('#') makes a string from its argument, without macro expansion
// e.g. If "version" is #define'd to be "4", then STRINGIFY_AWE(version) will return the string "version", not "4"
// To expand "version" to its value before making the string, use STRINGIFY(version) instead
#define STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s) # s
#define STRINGIFY(s) STRINGIFY_ARGUMENT_WITHOUT_EXPANSION(s)
// 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
const char VersionString_SCCS[] = "@(#) mDNSResponderHelper " STRINGIFY(mDNSResponderVersion) " (" __DATE__ " " __TIME__ ")";
#if _BUILDING_XCODE_PROJECT_
// If the process crashes, then this string will be magically included in the automatically-generated crash log
const char *__crashreporter_info__ = VersionString_SCCS + 5;
asm (".desc ___crashreporter_info__, 0x10");
#endif
