messaging.c

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	/* create the messaging directory if needed */
	mkdir(dir, 0700);

	msg->base_path     = talloc_reference(msg, dir);
	msg->path          = messaging_path(msg, server_id);
	msg->server_id     = server_id;
	msg->iconv_convenience = iconv_convenience;
	msg->idr           = idr_init(msg);
	msg->dispatch_tree = idr_init(msg);
	msg->start_time    = timeval_current();

	status = socket_create("unix", SOCKET_TYPE_DGRAM, &msg->sock, 0);
	if (!NT_STATUS_IS_OK(status)) {
		talloc_free(msg);
		return NULL;
	}

	/* by stealing here we ensure that the socket is cleaned up (and even 
	   deleted) on exit */
	talloc_steal(msg, msg->sock);

	path = socket_address_from_strings(msg, msg->sock->backend_name, 
					   msg->path, 0);
	if (!path) {
		talloc_free(msg);
		return NULL;
	}

	status = socket_listen(msg->sock, path, 50, 0);
	if (!NT_STATUS_IS_OK(status)) {
		DEBUG(0,("Unable to setup messaging listener for '%s':%s\n", msg->path, nt_errstr(status)));
		talloc_free(msg);
		return NULL;
	}

	/* it needs to be non blocking for sends */
	set_blocking(socket_get_fd(msg->sock), false);

	msg->event.ev   = talloc_reference(msg, ev);
	msg->event.fde	= event_add_fd(ev, msg, socket_get_fd(msg->sock), 
				       EVENT_FD_READ, messaging_handler, msg);

	talloc_set_destructor(msg, messaging_destructor);
	
	messaging_register(msg, NULL, MSG_PING, ping_message);
	messaging_register(msg, NULL, MSG_IRPC, irpc_handler);
	IRPC_REGISTER(msg, irpc, IRPC_UPTIME, irpc_uptime, msg);

	return msg;
}

/* 
   A hack, for the short term until we get 'client only' messaging in place 
*/
struct messaging_context *messaging_client_init(TALLOC_CTX *mem_ctx, 
						const char *dir,
						struct smb_iconv_convenience *iconv_convenience,
						struct event_context *ev)
{
	struct server_id id;
	ZERO_STRUCT(id);
	id.id = random() % 0x10000000;
	return messaging_init(mem_ctx, dir, id, iconv_convenience, ev);
}
/*
  a list of registered irpc server functions
*/
struct irpc_list {
	struct irpc_list *next, *prev;
	struct GUID uuid;
	const struct ndr_interface_table *table;
	int callnum;
	irpc_function_t fn;
	void *private;
};


/*
  register a irpc server function
*/
NTSTATUS irpc_register(struct messaging_context *msg_ctx, 
		       const struct ndr_interface_table *table, 
		       int callnum, irpc_function_t fn, void *private)
{
	struct irpc_list *irpc;

	/* override an existing handler, if any */
	for (irpc=msg_ctx->irpc; irpc; irpc=irpc->next) {
		if (irpc->table == table && irpc->callnum == callnum) {
			break;
		}
	}
	if (irpc == NULL) {
		irpc = talloc(msg_ctx, struct irpc_list);
		NT_STATUS_HAVE_NO_MEMORY(irpc);
		DLIST_ADD(msg_ctx->irpc, irpc);
	}

	irpc->table   = table;
	irpc->callnum = callnum;
	irpc->fn      = fn;
	irpc->private = private;
	irpc->uuid = irpc->table->syntax_id.uuid;

	return NT_STATUS_OK;
}


/*
  handle an incoming irpc reply message
*/
static void irpc_handler_reply(struct messaging_context *msg_ctx, struct irpc_message *m)
{
	struct irpc_request *irpc;
	enum ndr_err_code ndr_err;

	irpc = (struct irpc_request *)idr_find(msg_ctx->idr, m->header.callid);
	if (irpc == NULL) return;

	/* parse the reply data */
	ndr_err = irpc->table->calls[irpc->callnum].ndr_pull(m->ndr, NDR_OUT, irpc->r);
	if (NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		irpc->status = m->header.status;
		talloc_steal(irpc->mem_ctx, m);
	} else {
		irpc->status = ndr_map_error2ntstatus(ndr_err);
		talloc_steal(irpc, m);
	}
	irpc->done = true;
	if (irpc->async.fn) {
		irpc->async.fn(irpc);
	}
}

/*
  send a irpc reply
*/
NTSTATUS irpc_send_reply(struct irpc_message *m, NTSTATUS status)
{
	struct ndr_push *push;
	DATA_BLOB packet;
	enum ndr_err_code ndr_err;

	m->header.status = status;

	/* setup the reply */
	push = ndr_push_init_ctx(m->ndr, m->msg_ctx->iconv_convenience);
	if (push == NULL) {
		status = NT_STATUS_NO_MEMORY;
		goto failed;
	}

	m->header.flags |= IRPC_FLAG_REPLY;

	/* construct the packet */
	ndr_err = ndr_push_irpc_header(push, NDR_SCALARS|NDR_BUFFERS, &m->header);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		status = ndr_map_error2ntstatus(ndr_err);
		goto failed;
	}

	ndr_err = m->irpc->table->calls[m->irpc->callnum].ndr_push(push, NDR_OUT, m->data);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		status = ndr_map_error2ntstatus(ndr_err);
		goto failed;
	}

	/* send the reply message */
	packet = ndr_push_blob(push);
	status = messaging_send(m->msg_ctx, m->from, MSG_IRPC, &packet);
	if (!NT_STATUS_IS_OK(status)) goto failed;

failed:
	talloc_free(m);
	return status;
}

/*
  handle an incoming irpc request message
*/
static void irpc_handler_request(struct messaging_context *msg_ctx, 
				 struct irpc_message *m)
{
	struct irpc_list *i;
	void *r;
	enum ndr_err_code ndr_err;

	for (i=msg_ctx->irpc; i; i=i->next) {
		if (GUID_equal(&i->uuid, &m->header.uuid) &&
		    i->table->syntax_id.if_version == m->header.if_version &&
		    i->callnum == m->header.callnum) {
			break;
		}
	}

	if (i == NULL) {
		/* no registered handler for this message */
		talloc_free(m);
		return;
	}

	/* allocate space for the structure */
	r = talloc_zero_size(m->ndr, i->table->calls[m->header.callnum].struct_size);
	if (r == NULL) goto failed;

	/* parse the request data */
	ndr_err = i->table->calls[i->callnum].ndr_pull(m->ndr, NDR_IN, r);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) goto failed;

	/* make the call */
	m->private     = i->private;
	m->defer_reply = false;
	m->msg_ctx     = msg_ctx;
	m->irpc        = i;
	m->data        = r;
	m->ev          = msg_ctx->event.ev;

	m->header.status = i->fn(m, r);

	if (m->defer_reply) {
		/* the server function has asked to defer the reply to later */
		talloc_steal(msg_ctx, m);
		return;
	}

	irpc_send_reply(m, m->header.status);
	return;

failed:
	talloc_free(m);
}

/*
  handle an incoming irpc message
*/
static void irpc_handler(struct messaging_context *msg_ctx, void *private, 
			 uint32_t msg_type, struct server_id src, DATA_BLOB *packet)
{
	struct irpc_message *m;
	enum ndr_err_code ndr_err;

	m = talloc(msg_ctx, struct irpc_message);
	if (m == NULL) goto failed;

	m->from = src;

	m->ndr = ndr_pull_init_blob(packet, m, msg_ctx->iconv_convenience);
	if (m->ndr == NULL) goto failed;

	m->ndr->flags |= LIBNDR_FLAG_REF_ALLOC;

	ndr_err = ndr_pull_irpc_header(m->ndr, NDR_BUFFERS|NDR_SCALARS, &m->header);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) goto failed;

	if (m->header.flags & IRPC_FLAG_REPLY) {
		irpc_handler_reply(msg_ctx, m);
	} else {
		irpc_handler_request(msg_ctx, m);
	}
	return;

failed:
	talloc_free(m);
}


/*
  destroy a irpc request
*/
static int irpc_destructor(struct irpc_request *irpc)
{
	if (irpc->callid != -1) {
		idr_remove(irpc->msg_ctx->idr, irpc->callid);
		irpc->callid = -1;
	}

	if (irpc->reject_free) {
		return -1;
	}
	return 0;
}

/*
  timeout a irpc request
*/
static void irpc_timeout(struct event_context *ev, struct timed_event *te, 
			 struct timeval t, void *private)
{
	struct irpc_request *irpc = talloc_get_type(private, struct irpc_request);
	irpc->status = NT_STATUS_IO_TIMEOUT;
	irpc->done = true;
	if (irpc->async.fn) {
		irpc->async.fn(irpc);
	}
}


/*
  make a irpc call - async send
*/
struct irpc_request *irpc_call_send(struct messaging_context *msg_ctx, 
				    struct server_id server_id, 
				    const struct ndr_interface_table *table, 
				    int callnum, void *r, TALLOC_CTX *ctx)
{
	struct irpc_header header;
	struct ndr_push *ndr;
	NTSTATUS status;
	DATA_BLOB packet;
	struct irpc_request *irpc;
	enum ndr_err_code ndr_err;

	irpc = talloc(msg_ctx, struct irpc_request);
	if (irpc == NULL) goto failed;

	irpc->msg_ctx  = msg_ctx;
	irpc->table    = table;
	irpc->callnum  = callnum;
	irpc->callid   = idr_get_new(msg_ctx->idr, irpc, UINT16_MAX);
	if (irpc->callid == -1) goto failed;
	irpc->r        = r;
	irpc->done     = false;
	irpc->async.fn = NULL;
	irpc->mem_ctx  = ctx;
	irpc->reject_free = false;

	talloc_set_destructor(irpc, irpc_destructor);

	/* setup the header */
	header.uuid = table->syntax_id.uuid;

	header.if_version = table->syntax_id.if_version;
	header.callid     = irpc->callid;
	header.callnum    = callnum;
	header.flags      = 0;
	header.status     = NT_STATUS_OK;

	/* construct the irpc packet */
	ndr = ndr_push_init_ctx(irpc, msg_ctx->iconv_convenience);
	if (ndr == NULL) goto failed;

	ndr_err = ndr_push_irpc_header(ndr, NDR_SCALARS|NDR_BUFFERS, &header);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) goto failed;

	ndr_err = table->calls[callnum].ndr_push(ndr, NDR_IN, r);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) goto failed;

	/* and send it */
	packet = ndr_push_blob(ndr);
	status = messaging_send(msg_ctx, server_id, MSG_IRPC, &packet);
	if (!NT_STATUS_IS_OK(status)) goto failed;

	event_add_timed(msg_ctx->event.ev, irpc, 
			timeval_current_ofs(IRPC_CALL_TIMEOUT, 0), 
			irpc_timeout, irpc);

	talloc_free(ndr);
	return irpc;

failed:
	talloc_free(irpc);
	return NULL;
}

/*
  wait for a irpc reply
*/
NTSTATUS irpc_call_recv(struct irpc_request *irpc)
{
	NTSTATUS status;

	NT_STATUS_HAVE_NO_MEMORY(irpc);

	irpc->reject_free = true;

	while (!irpc->done) {
		if (event_loop_once(irpc->msg_ctx->event.ev) != 0) {
			return NT_STATUS_CONNECTION_DISCONNECTED;
		}
	}

	irpc->reject_free = false;

	status = irpc->status;
	talloc_free(irpc);
	return status;
}

/*
  perform a synchronous irpc request
*/
NTSTATUS irpc_call(struct messaging_context *msg_ctx, 
		   struct server_id server_id, 
		   const struct ndr_interface_table *table, 
		   int callnum, void *r,
		   TALLOC_CTX *mem_ctx)
{
	struct irpc_request *irpc = irpc_call_send(msg_ctx, server_id, 
						   table, callnum, r, mem_ctx);
	return irpc_call_recv(irpc);
}

/*
  open the naming database
*/
static struct tdb_wrap *irpc_namedb_open(struct messaging_context *msg_ctx)
{
	struct tdb_wrap *t;
	char *path = talloc_asprintf(msg_ctx, "%s/names.tdb", msg_ctx->base_path);
	if (path == NULL) {
		return NULL;
	}
	t = tdb_wrap_open(msg_ctx, path, 0, 0, O_RDWR|O_CREAT, 0660);
	talloc_free(path);
	return t;
}
	

/*
  add a string name that this irpc server can be called on
*/
NTSTATUS irpc_add_name(struct messaging_context *msg_ctx, const char *name)
{
	struct tdb_wrap *t;
	TDB_DATA rec;
	int count;
	NTSTATUS status = NT_STATUS_OK;

	t = irpc_namedb_open(msg_ctx);
	NT_STATUS_HAVE_NO_MEMORY(t);

	if (tdb_lock_bystring(t->tdb, name) != 0) {
		talloc_free(t);
		return NT_STATUS_LOCK_NOT_GRANTED;
	}
	rec = tdb_fetch_bystring(t->tdb, name);
	count = rec.dsize / sizeof(struct server_id);
	rec.dptr = (unsigned char *)realloc_p(rec.dptr, struct server_id, count+1);
	rec.dsize += sizeof(struct server_id);
	if (rec.dptr == NULL) {
		tdb_unlock_bystring(t->tdb, name);
		talloc_free(t);
		return NT_STATUS_NO_MEMORY;
	}
	((struct server_id *)rec.dptr)[count] = msg_ctx->server_id;
	if (tdb_store_bystring(t->tdb, name, rec, 0) != 0) {
		status = NT_STATUS_INTERNAL_ERROR;
	}
	free(rec.dptr);
	tdb_unlock_bystring(t->tdb, name);
	talloc_free(t);

	msg_ctx->names = str_list_add(msg_ctx->names, name);
	talloc_steal(msg_ctx, msg_ctx->names);

	return status;
}

/*
  return a list of server ids for a server name
*/
struct server_id *irpc_servers_byname(struct messaging_context *msg_ctx,
				      TALLOC_CTX *mem_ctx,
				      const char *name)
{
	struct tdb_wrap *t;
	TDB_DATA rec;
	int count, i;
	struct server_id *ret;

	t = irpc_namedb_open(msg_ctx);
	if (t == NULL) {
		return NULL;
	}

	if (tdb_lock_bystring(t->tdb, name) != 0) {
		talloc_free(t);
		return NULL;
	}
	rec = tdb_fetch_bystring(t->tdb, name);
	if (rec.dptr == NULL) {
		tdb_unlock_bystring(t->tdb, name);
		talloc_free(t);
		return NULL;
	}
	count = rec.dsize / sizeof(struct server_id);
	ret = talloc_array(mem_ctx, struct server_id, count+1);
	if (ret == NULL) {
		tdb_unlock_bystring(t->tdb, name);
		talloc_free(t);
		return NULL;
	}
	for (i=0;i<count;i++) {
		ret[i] = ((struct server_id *)rec.dptr)[i];
	}
	ret[i] = cluster_id(0, 0);
	free(rec.dptr);
	tdb_unlock_bystring(t->tdb, name);
	talloc_free(t);

	return ret;
}

/*
  remove a name from a messaging context
*/
void irpc_remove_name(struct messaging_context *msg_ctx, const char *name)
{
	struct tdb_wrap *t;
	TDB_DATA rec;
	int count, i;
	struct server_id *ids;

	str_list_remove(msg_ctx->names, name);

	t = irpc_namedb_open(msg_ctx);
	if (t == NULL) {
		return;
	}

	if (tdb_lock_bystring(t->tdb, name) != 0) {
		talloc_free(t);
		return;
	}
	rec = tdb_fetch_bystring(t->tdb, name);
	if (rec.dptr == NULL) {
		tdb_unlock_bystring(t->tdb, name);
		talloc_free(t);
		return;
	}
	count = rec.dsize / sizeof(struct server_id);
	if (count == 0) {
		free(rec.dptr);
		tdb_unlock_bystring(t->tdb, name);
		talloc_free(t);
		return;
	}
	ids = (struct server_id *)rec.dptr;
	for (i=0;i<count;i++) {
		if (cluster_id_equal(&ids[i], &msg_ctx->server_id)) {
			if (i < count-1) {
				memmove(ids+i, ids+i+1, 
					sizeof(struct server_id) * (count-(i+1)));
			}
			rec.dsize -= sizeof(struct server_id);
			break;
		}
	}
	tdb_store_bystring(t->tdb, name, rec, 0);
	free(rec.dptr);
	tdb_unlock_bystring(t->tdb, name);
	talloc_free(t);
}

struct server_id messaging_get_server_id(struct messaging_context *msg_ctx)
{
	return msg_ctx->server_id;
}