mosquitto/src/mosquitto.c

/*
Copyright (c) 2009-2020 Roger Light <roger@atchoo.org>

All rights reserved. This program and the accompanying materials
are made available under the terms of the Eclipse Public License v1.0
and Eclipse Distribution License v1.0 which accompany this distribution.
 
The Eclipse Public License is available at
   http://www.eclipse.org/legal/epl-v10.html
and the Eclipse Distribution License is available at
  http://www.eclipse.org/org/documents/edl-v10.php.
 
Contributors:
   Roger Light - initial implementation and documentation.
*/

#include "config.h"

#ifndef WIN32
/* For initgroups() */
#  include <unistd.h>
#  include <grp.h>
#  include <assert.h>
#endif

#ifndef WIN32
#include <pwd.h>
#else
#include <process.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#endif

#ifndef WIN32
#  include <sys/time.h>
#endif

#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#ifdef WITH_SYSTEMD
#  include <systemd/sd-daemon.h>
#endif
#ifdef WITH_WRAP
#include <tcpd.h>
#endif
#ifdef WITH_WEBSOCKETS
#  include <libwebsockets.h>
#endif

#include "mosquitto_broker_internal.h"
#include "memory_mosq.h"
#include "misc_mosq.h"
#include "util_mosq.h"

struct mosquitto_db int_db;

bool flag_reload = false;
#ifdef WITH_PERSISTENCE
bool flag_db_backup = false;
#endif
bool flag_tree_print = false;
int run;
#ifdef WITH_WRAP
#include <syslog.h>
int allow_severity = LOG_INFO;
int deny_severity = LOG_INFO;
#endif

void handle_sigint(int signal);
void handle_sigusr1(int signal);
void handle_sigusr2(int signal);
#ifdef SIGHUP
void handle_sighup(int signal);
#endif

struct mosquitto_db *mosquitto__get_db(void)
{
	return &int_db;
}

/* mosquitto shouldn't run as root.
 * This function will attempt to change to an unprivileged user and group if
 * running as root. The user is given in config->user.
 * Returns 1 on failure (unknown user, setuid/setgid failure)
 * Returns 0 on success.
 * Note that setting config->user to "root" does not produce an error, but it
 * strongly discouraged.
 */
int drop_privileges(struct mosquitto__config *config)
{
#if !defined(__CYGWIN__) && !defined(WIN32)
	struct passwd *pwd;
	char *err;
	int rc;

	const char *snap = getenv("SNAP_NAME");
	if(snap && !strcmp(snap, "mosquitto")){
		/* Don't attempt to drop privileges if running as a snap */
		return MOSQ_ERR_SUCCESS;
	}

	if(geteuid() == 0){
		if(config->user && strcmp(config->user, "root")){
			pwd = getpwnam(config->user);
			if(!pwd){
				if(strcmp(config->user, "mosquitto")){
					log__printf(NULL, MOSQ_LOG_ERR, "Error: Unable to drop privileges to '%s' because this user does not exist.", config->user);
					return 1;
				}else{
					log__printf(NULL, MOSQ_LOG_ERR, "Warning: Unable to drop privileges to '%s' because this user does not exist. Trying 'nobody' instead.", config->user);
					pwd = getpwnam("nobody");
					if(!pwd){
						log__printf(NULL, MOSQ_LOG_ERR, "Error: Unable to drop privileges to 'nobody'.");
						return 1;
					}
				}
			}
			if(initgroups(config->user, pwd->pw_gid) == -1){
				err = strerror(errno);
				log__printf(NULL, MOSQ_LOG_ERR, "Error setting groups whilst dropping privileges: %s.", err);
				return 1;
			}
			rc = setgid(pwd->pw_gid);
			if(rc == -1){
				err = strerror(errno);
				log__printf(NULL, MOSQ_LOG_ERR, "Error setting gid whilst dropping privileges: %s.", err);
				return 1;
			}
			rc = setuid(pwd->pw_uid);
			if(rc == -1){
				err = strerror(errno);
				log__printf(NULL, MOSQ_LOG_ERR, "Error setting uid whilst dropping privileges: %s.", err);
				return 1;
			}
		}
		if(geteuid() == 0 || getegid() == 0){
			log__printf(NULL, MOSQ_LOG_WARNING, "Warning: Mosquitto should not be run as root/administrator.");
		}
	}
#endif
	return MOSQ_ERR_SUCCESS;
}

void mosquitto__daemonise(void)
{
#ifndef WIN32
	char *err;
	pid_t pid;

	pid = fork();
	if(pid < 0){
		err = strerror(errno);
		log__printf(NULL, MOSQ_LOG_ERR, "Error in fork: %s", err);
		exit(1);
	}
	if(pid > 0){
		exit(0);
	}
	if(setsid() < 0){
		err = strerror(errno);
		log__printf(NULL, MOSQ_LOG_ERR, "Error in setsid: %s", err);
		exit(1);
	}

	assert(freopen("/dev/null", "r", stdin));
	assert(freopen("/dev/null", "w", stdout));
	assert(freopen("/dev/null", "w", stderr));
#else
	log__printf(NULL, MOSQ_LOG_WARNING, "Warning: Can't start in daemon mode in Windows.");
#endif
}


void listener__set_defaults(struct mosquitto__listener *listener)
{
	listener->security_options.allow_anonymous = -1;
	listener->security_options.allow_zero_length_clientid = true;
	listener->protocol = mp_mqtt;
	listener->max_connections = -1;
	listener->maximum_qos = 2;
	listener->max_topic_alias = 10;
}


void listeners__reload_all_certificates(struct mosquitto_db *db)
{
#ifdef WITH_TLS
	int i;
	int rc;
	struct mosquitto__listener *listener;

	for(i=0; i<db->config->listener_count; i++){
		listener = &db->config->listeners[i];
		if(listener->ssl_ctx && listener->certfile && listener->keyfile){
			rc = net__load_certificates(listener);
			if(rc){
				log__printf(NULL, MOSQ_LOG_ERR, "Error when reloading certificate '%s' or key '%s'.",
						listener->certfile, listener->keyfile);
			}
		}
	}
#endif
}


int listeners__start_single_mqtt(struct mosquitto_db *db, mosq_sock_t **listensock, int *listensock_count, int *listensock_index, struct mosquitto__listener *listener)
{
	int i;
	mosq_sock_t *listensock_new;

	if(net__socket_listen(listener)){
		return 1;
	}
	(*listensock_count) += listener->sock_count;
	listensock_new = mosquitto__realloc(*listensock, sizeof(mosq_sock_t)*(size_t)(*listensock_count));
	if(!listensock_new){
		return 1;
	}
	*listensock = listensock_new;

	for(i=0; i<listener->sock_count; i++){
		if(listener->socks[i] == INVALID_SOCKET){
			return 1;
		}
		(*listensock)[*listensock_index] = listener->socks[i];
		(*listensock_index)++;
	}
	return MOSQ_ERR_SUCCESS;
}


int listeners__add_local(struct mosquitto_db *db, mosq_sock_t **listensock, int *listensock_count, int *listensock_index, const char *host, uint16_t port)
{
	struct mosquitto__listener *listeners;

	listeners = mosquitto__realloc(db->config->listeners, (size_t)(db->config->listener_count+1)*sizeof(struct mosquitto__listener));
	if(listeners == NULL){
		return MOSQ_ERR_NOMEM;
	}
	db->config->listener_count++;
	db->config->listeners = listeners;
	memset(&listeners[db->config->listener_count-1], 0, sizeof(struct mosquitto__listener));

	listener__set_defaults(&listeners[db->config->listener_count-1]);
	listeners[db->config->listener_count-1].security_options.allow_anonymous = true;
	listeners[db->config->listener_count-1].port = port;
	listeners[db->config->listener_count-1].host = mosquitto__strdup(host);
	if(listeners[db->config->listener_count-1].host == NULL){
		return MOSQ_ERR_NOMEM;
	}
	if(listeners__start_single_mqtt(db, listensock, listensock_count, listensock_index, &listeners[db->config->listener_count-1])){
		mosquitto__free(listeners[db->config->listener_count-1].host);
		listeners[db->config->listener_count-1].host = NULL;
		db->config->listener_count--;
		return MOSQ_ERR_UNKNOWN;
	}
	return MOSQ_ERR_SUCCESS;
}

int listeners__start_local_only(struct mosquitto_db *db, mosq_sock_t **listensock, int *listensock_count)
{
	/* Attempt to open listeners bound to 127.0.0.1 and ::1 only */
	int i;
	int listensock_index = 0;
	int rc;

	log__printf(NULL, MOSQ_LOG_WARNING, "Starting in local only mode. Connections will only be possible from clients running on this machine.");
	log__printf(NULL, MOSQ_LOG_WARNING, "Create a configuration file which defines a listener to allow remote access.");
	if(db->config->cmd_port_count == 0){
		rc = listeners__add_local(db, listensock, listensock_count, &listensock_index, "127.0.0.1", 1883);
		if(rc == MOSQ_ERR_NOMEM) return MOSQ_ERR_NOMEM;
		rc = listeners__add_local(db, listensock, listensock_count, &listensock_index, "::1", 1883);
		if(rc == MOSQ_ERR_NOMEM) return MOSQ_ERR_NOMEM;
	}else{
		for(i=0; i<db->config->cmd_port_count; i++){
			rc = listeners__add_local(db, listensock, listensock_count, &listensock_index, "127.0.0.1", db->config->cmd_port[i]);
			if(rc == MOSQ_ERR_NOMEM) return MOSQ_ERR_NOMEM;
			rc = listeners__add_local(db, listensock, listensock_count, &listensock_index, "::1", db->config->cmd_port[i]);
			if(rc == MOSQ_ERR_NOMEM) return MOSQ_ERR_NOMEM;
		}
	}

	if(db->config->listener_count > 0){
		return MOSQ_ERR_SUCCESS;
	}else{
		return MOSQ_ERR_UNKNOWN;
	}
}


int listeners__start(struct mosquitto_db *db, mosq_sock_t **listensock, int *listensock_count)
{
	int i;
	int listensock_index = 0;

	listensock_index = 0;
	(*listensock_count) = 0;

	if(db->config->listener_count == 0){
		if(listeners__start_local_only(db, listensock, listensock_count)){
			db__close(db);
			if(db->config->pid_file){
				remove(db->config->pid_file);
			}
			return 1;
		}
		return MOSQ_ERR_SUCCESS;
	}

	for(i=0; i<db->config->listener_count; i++){
		if(db->config->listeners[i].protocol == mp_mqtt){
			if(listeners__start_single_mqtt(db, listensock, listensock_count, &listensock_index, &db->config->listeners[i])){
				db__close(db);
				if(db->config->pid_file){
					remove(db->config->pid_file);
				}
				return 1;
			}
		}else if(db->config->listeners[i].protocol == mp_websockets){
#ifdef WITH_WEBSOCKETS
			db->config->listeners[i].ws_context = mosq_websockets_init(&db->config->listeners[i], db->config);
			if(!db->config->listeners[i].ws_context){
				log__printf(NULL, MOSQ_LOG_ERR, "Error: Unable to create websockets listener on port %d.", db->config->listeners[i].port);
				return 1;
			}
#endif
		}
	}
	if((*listensock) == NULL){
		log__printf(NULL, MOSQ_LOG_ERR, "Error: Unable to start any listening sockets, exiting.");
		return 1;
	}
	return MOSQ_ERR_SUCCESS;
}


void listeners__stop(struct mosquitto_db *db, mosq_sock_t *listensock, int listensock_count)
{
	int i;

	for(i=0; i<db->config->listener_count; i++){
#ifdef WITH_WEBSOCKETS
		if(db->config->listeners[i].ws_context){
			libwebsocket_context_destroy(db->config->listeners[i].ws_context);
		}
		mosquitto__free(db->config->listeners[i].ws_protocol);
#endif
#ifdef WITH_UNIX_SOCKETS
		if(db->config->listeners[i].unix_socket_path != NULL){
			unlink(db->config->listeners[i].unix_socket_path);
		}
#endif
	}

	for(i=0; i<listensock_count; i++){
		if(listensock[i] != INVALID_SOCKET){
			COMPAT_CLOSE(listensock[i]);
		}
	}
	mosquitto__free(listensock);
}


void signal__setup(void)
{
	signal(SIGINT, handle_sigint);
	signal(SIGTERM, handle_sigint);
#ifdef SIGHUP
	signal(SIGHUP, handle_sighup);
#endif
#ifndef WIN32
	signal(SIGUSR1, handle_sigusr1);
	signal(SIGUSR2, handle_sigusr2);
	signal(SIGPIPE, SIG_IGN);
#endif
#ifdef WIN32
	CreateThread(NULL, 0, SigThreadProc, NULL, 0, NULL);
#endif
}


int pid__write(struct mosquitto_db *db)
{
	FILE *pid;

	if(db->config->pid_file){
		pid = mosquitto__fopen(db->config->pid_file, "wt", false);
		if(pid){
			fprintf(pid, "%d", getpid());
			fclose(pid);
		}else{
			log__printf(NULL, MOSQ_LOG_ERR, "Error: Unable to write pid file.");
			return 1;
		}
	}
	return MOSQ_ERR_SUCCESS;
}


int main(int argc, char *argv[])
{
	mosq_sock_t *listensock = NULL;
	int listensock_count = 0;
	struct mosquitto__config config;
#ifdef WITH_BRIDGE
	int i;
#endif
	int rc;
#ifdef WIN32
	SYSTEMTIME st;
#else
	struct timeval tv;
#endif
	struct mosquitto *ctxt, *ctxt_tmp;

#if defined(WIN32) || defined(__CYGWIN__)
	if(argc == 2){
		if(!strcmp(argv[1], "run")){
			service_run();
			return 0;
		}else if(!strcmp(argv[1], "install")){
			service_install();
			return 0;
		}else if(!strcmp(argv[1], "uninstall")){
			service_uninstall();
			return 0;
		}
	}
#endif


#ifdef WIN32
	GetSystemTime(&st);
	srand(st.wSecond + st.wMilliseconds);
#else
	gettimeofday(&tv, NULL);
	srand((unsigned int)(tv.tv_sec + tv.tv_usec));
#endif

#ifdef WIN32
	_setmaxstdio(2048);
#endif

	memset(&int_db, 0, sizeof(struct mosquitto_db));

	net__broker_init();

	config__init(&int_db, &config);
	rc = config__parse_args(&int_db, &config, argc, argv);
	if(rc != MOSQ_ERR_SUCCESS) return rc;
	int_db.config = &config;

	/* Drop privileges permanently immediately after the config is loaded.
	 * This requires the user to ensure that all certificates, log locations,
	 * etc. are accessible my the `mosquitto` or other unprivileged user.
	 */
	rc = drop_privileges(&config);
	if(rc != MOSQ_ERR_SUCCESS) return rc;

	if(config.daemon){
		mosquitto__daemonise();
	}

	if(pid__write(&int_db)) return 1;

	rc = db__open(&config, &int_db);
	if(rc != MOSQ_ERR_SUCCESS){
		log__printf(NULL, MOSQ_LOG_ERR, "Error: Couldn't open database.");
		return rc;
	}

	/* Initialise logging only after initialising the database in case we're
	 * logging to topics */
	if(log__init(&config)){
		rc = 1;
		return rc;
	}
	log__printf(NULL, MOSQ_LOG_INFO, "mosquitto version %s starting", VERSION);
	if(int_db.config_file){
		log__printf(NULL, MOSQ_LOG_INFO, "Config loaded from %s.", int_db.config_file);
	}else{
		log__printf(NULL, MOSQ_LOG_INFO, "Using default config.");
	}

	rc = mosquitto_security_module_init(&int_db);
	if(rc) return rc;
	rc = mosquitto_security_init(&int_db, false);
	if(rc) return rc;

	/* After loading persisted clients and ACLs, try to associate them,
	 * so persisted subscriptions can start storing messages */
	HASH_ITER(hh_id, int_db.contexts_by_id, ctxt, ctxt_tmp){
		if(ctxt && !ctxt->clean_start && ctxt->username){
			rc = acl__find_acls(&int_db, ctxt);
			if(rc){
				log__printf(NULL, MOSQ_LOG_WARNING, "Failed to associate persisted user %s with ACLs, "
					"likely due to changed ports while using a per_listener_settings configuration.", ctxt->username);
			}
		}
	}

#ifdef WITH_SYS_TREE
	sys_tree__init(&int_db);
#endif

	if(listeners__start(&int_db, &listensock, &listensock_count)) return 1;

	signal__setup();

#ifdef WITH_BRIDGE
	bridge__start_all(&int_db);
#endif

	log__printf(NULL, MOSQ_LOG_INFO, "mosquitto version %s running", VERSION);
#ifdef WITH_SYSTEMD
	sd_notify(0, "READY=1");
#endif

	run = 1;
	rc = mosquitto_main_loop(&int_db, listensock, listensock_count);

	log__printf(NULL, MOSQ_LOG_INFO, "mosquitto version %s terminating", VERSION);

	/* FIXME - this isn't quite right, all wills with will delay zero should be
	 * sent now, but those with positive will delay should be persisted and
	 * restored, pending the client reconnecting in time. */
	HASH_ITER(hh_id, int_db.contexts_by_id, ctxt, ctxt_tmp){
		context__send_will(&int_db, ctxt);
	}
	will_delay__send_all(&int_db);

#ifdef WITH_PERSISTENCE
	persist__backup(&int_db, true);
#endif
	session_expiry__remove_all(&int_db);

	HASH_ITER(hh_id, int_db.contexts_by_id, ctxt, ctxt_tmp){
#ifdef WITH_WEBSOCKETS
		if(!ctxt->wsi){
			context__cleanup(&int_db, ctxt, true);
		}
#else
		context__cleanup(&int_db, ctxt, true);
#endif
	}
	HASH_ITER(hh_sock, int_db.contexts_by_sock, ctxt, ctxt_tmp){
		context__cleanup(&int_db, ctxt, true);
	}
#ifdef WITH_BRIDGE
	for(i=0; i<int_db.bridge_count; i++){
		if(int_db.bridges[i]){
			context__cleanup(&int_db, int_db.bridges[i], true);
		}
	}
	mosquitto__free(int_db.bridges);
#endif
	context__free_disused(&int_db);

	db__close(&int_db);

	listeners__stop(&int_db, listensock, listensock_count);

	mosquitto_security_module_cleanup(&int_db);

	if(config.pid_file){
		remove(config.pid_file);
	}

	log__close(&config);
	config__cleanup(int_db.config);
	net__broker_cleanup();

	return rc;
}

#ifdef WIN32
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
	char **argv;
	int argc = 1;
	char *token;
	char *saveptr = NULL;
	int rc;

	argv = mosquitto__malloc(sizeof(char *)*1);
	argv[0] = "mosquitto";
	token = strtok_r(lpCmdLine, " ", &saveptr);
	while(token){
		argc++;
		argv = mosquitto__realloc(argv, sizeof(char *)*argc);
		if(!argv){
			fprintf(stderr, "Error: Out of memory.\n");
			return MOSQ_ERR_NOMEM;
		}
		argv[argc-1] = token;
		token = strtok_r(NULL, " ", &saveptr);
	}
	rc = main(argc, argv);
	mosquitto__free(argv);
	return rc;
}
#endif