4  * Low-level kernel interface to the XenStore.
52 #include <xen/xen-os.h>
85  * guest either via the xen_start_info structure for a fully para-
116 /*-------------------------- Private Data Structures ------------------------*/
218 	 * The HVM guest pseudo-physical frame number.  This is Xen's mapping
240 	 * Xenstore is a user-space process that usually runs in Dom0,
254 /*-------------------------------- Global Data ------------------------------*/
257 /*------------------------- Private Utility Functions -----------------------*/
261  * strings in a buffer.
263  * \param strings  A pointer to a contiguous buffer of NUL terminated strings.
264  * \param dest	   An array to store pointers to each string found in strings.
265  * \param len	   The length of the buffer pointed to by strings.
267  * \return  A count of the number of strings found.
270 extract_strings(const char *strings, const char **dest, u_int len)  in extract_strings()  argument
272 	u_int num;  in extract_strings()  local
275 	for (p = strings, num = 0; p < strings + len; p += strlen(p) + 1) {  in extract_strings()
278 		num++;  in extract_strings()
281 	return (num);  in extract_strings()
286  * strings into an array of pointers to strings.
292  * The storage addressed by strings is free'd prior to split returning.
294  * \param strings  A pointer to a contiguous buffer of NUL terminated strings.
295  * \param len	   The length of the buffer pointed to by strings.
296  * \param num	   The number of strings found and returned in the strings
299  * \return  An array of pointers to the strings found in the input buffer.
302 split(char *strings, u_int len, u_int *num)  in split()  argument
308 		strings[len - 1] = '\0';  in split()
310 	/* Count the strings. */  in split()
311 	*num = extract_strings(strings, /*dest*/NULL, len);  in split()
314 	ret = malloc(*num * sizeof(char *) + len, M_XENSTORE, M_WAITOK);  in split()
315 	memcpy(&ret[*num], strings, len);  in split()
316 	free(strings, M_XENSTORE);  in split()
319 	strings = (char *)&ret[*num];  in split()
320 	(void)extract_strings(strings, /*dest*/ret, len);  in split()
325 /*------------------------- Public Utility Functions -------------------------*/
326 /*------- API comments for these methods can be found in xenstorevar.h -------*/
343 /*-------------------- Low Level Communication Management --------------------*/
390 	return ((prod - cons) <= XENSTORE_RING_SIZE);  in xs_check_indexes()
409 	*len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(prod);  in xs_get_output_chunk()
410 	if ((XENSTORE_RING_SIZE - (prod - cons)) < *len)  in xs_get_output_chunk()
411 		*len = XENSTORE_RING_SIZE - (prod - cons);  in xs_get_output_chunk()
431 	*len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(cons);  in xs_get_input_chunk()
432 	if ((prod - cons) < *len)  in xs_get_input_chunk()
433 		*len = prod - cons;  in xs_get_input_chunk()
465 		cons = xen_store->req_cons;  in xs_write_store()
466 		prod = xen_store->req_prod;  in xs_write_store()
467 		if ((prod - cons) == XENSTORE_RING_SIZE) {  in xs_write_store()
492 			xen_store->req_cons = xen_store->req_prod = 0;  in xs_write_store()
496 		dst = xs_get_output_chunk(cons, prod, xen_store->req, &avail);  in xs_write_store()
502 		len -= avail;  in xs_write_store()
511 		xen_store->req_prod += avail;  in xs_write_store()
553 		cons = xen_store->rsp_cons;  in xs_read_store()
554 		prod = xen_store->rsp_prod;  in xs_read_store()
578 			xen_store->rsp_cons = xen_store->rsp_prod = 0;  in xs_read_store()
582 		src = xs_get_input_chunk(cons, prod, xen_store->rsp, &avail);  in xs_read_store()
594 		len -= avail;  in xs_read_store()
602 		xen_store->rsp_cons += avail;  in xs_read_store()
614 /*----------------------- Received Message Processing ------------------------*/
632 	error = xs_read_store(&msg->hdr, sizeof(msg->hdr));  in xs_process_msg()
638 	body = malloc(msg->hdr.len + 1, M_XENSTORE, M_WAITOK);  in xs_process_msg()
639 	error = xs_read_store(body, msg->hdr.len);  in xs_process_msg()
645 	body[msg->hdr.len] = '\0';  in xs_process_msg()
647 	*type = msg->hdr.type;  in xs_process_msg()
648 	if (msg->hdr.type == XS_WATCH_EVENT) {  in xs_process_msg()
649 		msg->u.watch.vec = split(body, msg->hdr.len,  in xs_process_msg()
650 		    &msg->u.watch.vec_size);  in xs_process_msg()
653 		msg->u.watch.handle = find_watch(  in xs_process_msg()
654 		    msg->u.watch.vec[XS_WATCH_TOKEN]);  in xs_process_msg()
656 		if (msg->u.watch.handle != NULL &&  in xs_process_msg()
657 		    (!msg->u.watch.handle->max_pending ||  in xs_process_msg()
658 		    msg->u.watch.handle->pending <  in xs_process_msg()
659 		    msg->u.watch.handle->max_pending)) {  in xs_process_msg()
660 			msg->u.watch.handle->pending++;  in xs_process_msg()
666 			free(msg->u.watch.vec, M_XENSTORE);  in xs_process_msg()
671 		msg->u.reply.body = body;  in xs_process_msg()
701 /*---------------- XenStore Message Request/Reply Processing -----------------*/
711  * \note Unknown error strings are converted to EINVAL.
757 	*type = msg->hdr.type;  in xs_read_reply()
759 		*len = msg->hdr.len;  in xs_read_reply()
760 	body = msg->u.reply.body;  in xs_read_reply()
768  * Pass-thru interface for XenStore access by userland processes
790 	if ((error = xs_write_store(msg, sizeof(*msg) + msg->len)) == 0)  in xs_dev_request_and_reply()
791 		error = xs_read_reply(&msg->type, &msg->len, result);  in xs_dev_request_and_reply()
798  * Send a message with an optionally muti-part body to the XenStore service.
896 /*------------------------- XenStore Watch Support ---------------------------*/
985 			msg->u.watch.handle->pending--;  in xenwatch_thread()
996 			if (msg->u.watch.handle->callback != NULL)  in xenwatch_thread()
997 				msg->u.watch.handle->callback(  in xenwatch_thread()
998 					msg->u.watch.handle,  in xenwatch_thread()
999 					(const char **)msg->u.watch.vec,  in xenwatch_thread()
1000 					msg->u.watch.vec_size);  in xenwatch_thread()
1001 			free(msg->u.watch.vec, M_XENSTORE);  in xenwatch_thread()
1009 /*----------- XenStore Configuration, Initialization, and Control ------------*/
1021 	if (xen_store->rsp_prod != xen_store->rsp_cons) {  in xs_init_comms()
1024 		    xen_store->rsp_cons, xen_store->rsp_prod);  in xs_init_comms()
1025 		xen_store->rsp_cons = xen_store->rsp_prod;  in xs_init_comms()
1041 /*------------------ Private Device Attachment Functions  --------------------*/
1097 	/* Allow us to get device_t from softc and vice-versa. */  in xs_attach()
1150 	xs.xenwatch_pid = p->p_pid;  in xs_attach()
1206 		xs_watch(watch->node, token);  in xs_resume()
1215 /*-------------------- Private Device Attachment Data  -----------------------*/
1240 /*------------------------------- Sysctl Data --------------------------------*/
1247 /*-------------------------------- Public API --------------------------------*/
1248 /*------- API comments for these methods can be found in xenstorevar.h -------*/
1272     u_int *num, const char ***result)  in xs_directory()  argument
1275 	char *strings;  in xs_directory()  local
1281 	    (void **)&strings);  in xs_directory()
1286 	*result = split(strings, len, num);  in xs_directory()
1470 		t->id = strtoul(id_str, NULL, 0);  in xs_transaction_start()
1580 	watch->pending = 0;  in xs_register_watch()
1588 	error = xs_watch(watch->node, token);  in xs_register_watch()
1620 	error = xs_unwatch(watch->node, token);  in xs_unregister_watch()
1623 		    watch->node, error);  in xs_unregister_watch()
1628 		if (msg->u.watch.handle != watch)  in xs_unregister_watch()
1631 		free(msg->u.watch.vec, M_XENSTORE);  in xs_unregister_watch()
1636 	/* Flush any currently-executing callback, unless we are it. :-) */  in xs_unregister_watch()
1637 	if (curproc->p_pid != xs.xenwatch_pid) {  in xs_unregister_watch()