main.c

非常好的dns解析软件

static isc_result_t
create_managers(void) {
	isc_result_t result;
#ifdef ISC_PLATFORM_USETHREADS
	unsigned int cpus_detected;
#endif

#ifdef ISC_PLATFORM_USETHREADS
	cpus_detected = isc_os_ncpus();
	if (ns_g_cpus == 0)
		ns_g_cpus = cpus_detected;
	isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
		      ISC_LOG_INFO, "found %u CPU%s, using %u worker thread%s",
		      cpus_detected, cpus_detected == 1 ? "" : "s",
		      ns_g_cpus, ns_g_cpus == 1 ? "" : "s");
#else
	ns_g_cpus = 1;
#endif
	result = isc_taskmgr_create(ns_g_mctx, ns_g_cpus, 0, &ns_g_taskmgr);
	if (result != ISC_R_SUCCESS) {
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "isc_taskmgr_create() failed: %s",
				 isc_result_totext(result));
		return (ISC_R_UNEXPECTED);
	}

	result = isc_timermgr_create(ns_g_mctx, &ns_g_timermgr);
	if (result != ISC_R_SUCCESS) {
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "isc_timermgr_create() failed: %s",
				 isc_result_totext(result));
		return (ISC_R_UNEXPECTED);
	}

	result = isc_socketmgr_create(ns_g_mctx, &ns_g_socketmgr);
	if (result != ISC_R_SUCCESS) {
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "isc_socketmgr_create() failed: %s",
				 isc_result_totext(result));
		return (ISC_R_UNEXPECTED);
	}

	result = isc_entropy_create(ns_g_mctx, &ns_g_entropy);
	if (result != ISC_R_SUCCESS) {
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "isc_entropy_create() failed: %s",
				 isc_result_totext(result));
		return (ISC_R_UNEXPECTED);
	}

	result = isc_hash_create(ns_g_mctx, ns_g_entropy, DNS_NAME_MAXWIRE);
	if (result != ISC_R_SUCCESS) {
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "isc_hash_create() failed: %s",
				 isc_result_totext(result));
		return (ISC_R_UNEXPECTED);
	}

	return (ISC_R_SUCCESS);
}

static void
destroy_managers(void) {
	ns_lwresd_shutdown();

	isc_entropy_detach(&ns_g_entropy);
	if (ns_g_fallbackentropy != NULL)
		isc_entropy_detach(&ns_g_fallbackentropy);

	/*
	 * isc_taskmgr_destroy() will block until all tasks have exited,
	 */
	isc_taskmgr_destroy(&ns_g_taskmgr);
	isc_timermgr_destroy(&ns_g_timermgr);
	isc_socketmgr_destroy(&ns_g_socketmgr);

	/*
	 * isc_hash_destroy() cannot be called as long as a resolver may be
	 * running.  Calling this after isc_taskmgr_destroy() ensures the
	 * call is safe.
	 */
	isc_hash_destroy();
}

static void
setup(void) {
	isc_result_t result;
#ifdef HAVE_LIBSCF
	char *instance = NULL;
#endif

	/*
	 * Get the user and group information before changing the root
	 * directory, so the administrator does not need to keep a copy
	 * of the user and group databases in the chroot'ed environment.
	 */
	ns_os_inituserinfo(ns_g_username);

	/*
	 * Initialize time conversion information
	 */
	ns_os_tzset();

	ns_os_opendevnull();

#ifdef HAVE_LIBSCF
	/* Check if named is under smf control, before chroot. */
	result = ns_smf_get_instance(&instance, 0, ns_g_mctx);
	/* We don't care about instance, just check if we got one. */
	if (result == ISC_R_SUCCESS)
		ns_smf_got_instance = 1;
	else
		ns_smf_got_instance = 0;
	if (instance != NULL)
		isc_mem_free(ns_g_mctx, instance);
#endif /* HAVE_LIBSCF */

#ifdef PATH_RANDOMDEV
	/*
	 * Initialize system's random device as fallback entropy source
	 * if running chroot'ed.
	 */
	if (ns_g_chrootdir != NULL) {
		result = isc_entropy_create(ns_g_mctx, &ns_g_fallbackentropy);
		if (result != ISC_R_SUCCESS)
			ns_main_earlyfatal("isc_entropy_create() failed: %s",
					   isc_result_totext(result));

		result = isc_entropy_createfilesource(ns_g_fallbackentropy,
						      PATH_RANDOMDEV);
		if (result != ISC_R_SUCCESS) {
			ns_main_earlywarning("could not open pre-chroot "
					     "entropy source %s: %s",
					     PATH_RANDOMDEV,
					     isc_result_totext(result));
			isc_entropy_detach(&ns_g_fallbackentropy);
		}
	}
#endif

	ns_os_chroot(ns_g_chrootdir);

	/*
	 * For operating systems which have a capability mechanism, now
	 * is the time to switch to minimal privs and change our user id.
	 * On traditional UNIX systems, this call will be a no-op, and we
	 * will change the user ID after reading the config file the first
	 * time.  (We need to read the config file to know which possibly
	 * privileged ports to bind() to.)
	 */
	ns_os_minprivs();

	result = ns_log_init(ISC_TF(ns_g_username != NULL));
	if (result != ISC_R_SUCCESS)
		ns_main_earlyfatal("ns_log_init() failed: %s",
				   isc_result_totext(result));

	/*
	 * Now is the time to daemonize (if we're not running in the
	 * foreground).  We waited until now because we wanted to get
	 * a valid logging context setup.  We cannot daemonize any later,
	 * because calling create_managers() will create threads, which
	 * would be lost after fork().
	 */
	if (!ns_g_foreground)
		ns_os_daemonize();

	/*
	 * We call isc_app_start() here as some versions of FreeBSD's fork()
	 * destroys all the signal handling it sets up.
	 */
	result = isc_app_start();
	if (result != ISC_R_SUCCESS)
		ns_main_earlyfatal("isc_app_start() failed: %s",
				   isc_result_totext(result));

	isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_MAIN,
		      ISC_LOG_NOTICE, "starting BIND %s%s", ns_g_version,
		      saved_command_line);

	/*
	 * Get the initial resource limits.
	 */
	(void)isc_resource_getlimit(isc_resource_stacksize,
				    &ns_g_initstacksize);
	(void)isc_resource_getlimit(isc_resource_datasize,
				    &ns_g_initdatasize);
	(void)isc_resource_getlimit(isc_resource_coresize,
				    &ns_g_initcoresize);
	(void)isc_resource_getlimit(isc_resource_openfiles,
				    &ns_g_initopenfiles);

	/*
	 * If the named configuration filename is relative, prepend the current
	 * directory's name before possibly changing to another directory.
	 */
	if (! isc_file_isabsolute(ns_g_conffile)) {
		result = isc_file_absolutepath(ns_g_conffile,
					       absolute_conffile,
					       sizeof(absolute_conffile));
		if (result != ISC_R_SUCCESS)
			ns_main_earlyfatal("could not construct absolute path of "
					   "configuration file: %s", 
					   isc_result_totext(result));
		ns_g_conffile = absolute_conffile;
	}

	result = create_managers();
	if (result != ISC_R_SUCCESS)
		ns_main_earlyfatal("create_managers() failed: %s",
				   isc_result_totext(result));

	ns_builtin_init();

	/*
	 * Add calls to register sdb drivers here.
	 */
	/* xxdb_init(); */

#ifdef DLZ
	/*
	 * Registyer any DLZ drivers.
	 */
	result = dlz_drivers_init();
	if (result != ISC_R_SUCCESS)
		ns_main_earlyfatal("dlz_drivers_init() failed: %s",
				   isc_result_totext(result));
#endif

	ns_server_create(ns_g_mctx, &ns_g_server);
}

static void
cleanup(void) {
	destroy_managers();

	ns_server_destroy(&ns_g_server);

	ns_builtin_deinit();

	/*
	 * Add calls to unregister sdb drivers here.
	 */
	/* xxdb_clear(); */

#ifdef DLZ
	/*
	 * Unregister any DLZ drivers.
	 */
	dlz_drivers_clear();
#endif

	dns_name_destroy();

	isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_MAIN,
		      ISC_LOG_NOTICE, "exiting");
	ns_log_shutdown();
}

static char *memstats = NULL;

void
ns_main_setmemstats(const char *filename) {
	/*
	 * Caller has to ensure locking.
	 */

	if (memstats != NULL) {
		free(memstats);
		memstats = NULL;
	}
	if (filename == NULL)
		return;
	memstats = malloc(strlen(filename) + 1);
	if (memstats)
		strcpy(memstats, filename);
}

#ifdef HAVE_LIBSCF
/*
 * Get FMRI for the named process.
 */
isc_result_t
ns_smf_get_instance(char **ins_name, int debug, isc_mem_t *mctx) {
	scf_handle_t *h = NULL;
	int namelen;
	char *instance;

	REQUIRE(ins_name != NULL && *ins_name == NULL);

	if ((h = scf_handle_create(SCF_VERSION)) == NULL) {
		if (debug)
			UNEXPECTED_ERROR(__FILE__, __LINE__,
					 "scf_handle_create() failed: %s",
			 		 scf_strerror(scf_error()));
		return (ISC_R_FAILURE);
	}

	if (scf_handle_bind(h) == -1) {
		if (debug)
			UNEXPECTED_ERROR(__FILE__, __LINE__,
					 "scf_handle_bind() failed: %s",
					 scf_strerror(scf_error()));
		scf_handle_destroy(h);
		return (ISC_R_FAILURE);
	}

	if ((namelen = scf_myname(h, NULL, 0)) == -1) {
		if (debug)
			UNEXPECTED_ERROR(__FILE__, __LINE__,
					 "scf_myname() failed: %s",
					 scf_strerror(scf_error()));
		scf_handle_destroy(h);
		return (ISC_R_FAILURE);
	}

	if ((instance = isc_mem_allocate(mctx, namelen + 1)) == NULL) {
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "ns_smf_get_instance memory "
				 "allocation failed: %s",
				 isc_result_totext(ISC_R_NOMEMORY));
		scf_handle_destroy(h);
		return (ISC_R_FAILURE);
	}

	if (scf_myname(h, instance, namelen + 1) == -1) {
		if (debug)
			UNEXPECTED_ERROR(__FILE__, __LINE__,
					 "scf_myname() failed: %s",
					 scf_strerror(scf_error()));
		scf_handle_destroy(h);
		isc_mem_free(mctx, instance);
		return (ISC_R_FAILURE);
	}

	scf_handle_destroy(h);
	*ins_name = instance;
	return (ISC_R_SUCCESS);
}
#endif /* HAVE_LIBSCF */

int
main(int argc, char *argv[]) {
	isc_result_t result;
#ifdef HAVE_LIBSCF
	char *instance = NULL;
#endif

	/*
	 * Record version in core image.
	 * strings named.core | grep "named version:"
	 */
	strlcat(version,
#ifdef __DATE__
		"named version: BIND " VERSION " (" __DATE__ ")",
#else
		"named version: BIND " VERSION,
#endif
		sizeof(version));
	result = isc_file_progname(*argv, program_name, sizeof(program_name));
	if (result != ISC_R_SUCCESS)
		ns_main_earlyfatal("program name too long");

	if (strcmp(program_name, "lwresd") == 0)
		ns_g_lwresdonly = ISC_TRUE;

	isc_assertion_setcallback(assertion_failed);
	isc_error_setfatal(library_fatal_error);
	isc_error_setunexpected(library_unexpected_error);

	ns_os_init(program_name);

	dns_result_register();
	dst_result_register();
	isccc_result_register();

	parse_command_line(argc, argv);

	/*
	 * Warn about common configuration error.
	 */
	if (ns_g_chrootdir != NULL) {
		int len = strlen(ns_g_chrootdir);
		if (strncmp(ns_g_chrootdir, ns_g_conffile, len) == 0 &&
		    (ns_g_conffile[len] == '/' || ns_g_conffile[len] == '\\'))
			ns_main_earlywarning("config filename (-c %s) contains "
					     "chroot path (-t %s)",
					     ns_g_conffile, ns_g_chrootdir);
	}

	result = isc_mem_create(0, 0, &ns_g_mctx);
	if (result != ISC_R_SUCCESS)
		ns_main_earlyfatal("isc_mem_create() failed: %s",
				   isc_result_totext(result));

	setup();

	/*
	 * Start things running and then wait for a shutdown request
	 * or reload.
	 */
	do {
		result = isc_app_run();

		if (result == ISC_R_RELOAD) {
			ns_server_reloadwanted(ns_g_server);
		} else if (result != ISC_R_SUCCESS) {
			UNEXPECTED_ERROR(__FILE__, __LINE__,
					 "isc_app_run(): %s",
					 isc_result_totext(result));
			/*
			 * Force exit.
			 */
			result = ISC_R_SUCCESS;
		}
	} while (result != ISC_R_SUCCESS);

#ifdef HAVE_LIBSCF
	if (ns_smf_want_disable == 1) {
		result = ns_smf_get_instance(&instance, 1, ns_g_mctx);
		if (result == ISC_R_SUCCESS && instance != NULL) {
			if (smf_disable_instance(instance, 0) != 0)
				UNEXPECTED_ERROR(__FILE__, __LINE__,
						 "smf_disable_instance() "
						 "failed for %s : %s",
						 instance,
						 scf_strerror(scf_error()));
		}
		if (instance != NULL)
			isc_mem_free(ns_g_mctx, instance);
	}
#endif /* HAVE_LIBSCF */

	cleanup();

	if (want_stats) {
		isc_mem_stats(ns_g_mctx, stdout);
		isc_mutex_stats(stdout);
	}
	if (memstats != NULL) {
		FILE *fp = NULL;
		result = isc_stdio_open(memstats, "w", &fp);
		if (result == ISC_R_SUCCESS) {
			isc_mem_stats(ns_g_mctx, fp);
			isc_mutex_stats(fp);
			isc_stdio_close(fp);
		}
	}
	isc_mem_destroy(&ns_g_mctx);
	isc_mem_checkdestroyed(stderr);

	ns_main_setmemstats(NULL);

	isc_app_finish();

	ns_os_closedevnull();

	ns_os_shutdown();

	return (0);
}