Samuel Thibault
2008-Jan-17 15:10 UTC
[Xen-devel] [PATCH] [Mini-OS] add xenbus token support and separate watch event queues
add xenbus token support and separate watch event queues
Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>
# HG changeset patch
# User Samuel Thibault <samuel.thibault@eu.citrix.com>
# Date 1200582503 0
# Node ID 112c1180720c87a0bfa99142399e3ef3f79f1711
# Parent 33d1c7f9217a1c915afe01fe822811ce69b3a90f
add xenbus token support and separate watch event queues
diff -r 33d1c7f9217a -r 112c1180720c extras/mini-os/include/xenbus.h
--- a/extras/mini-os/include/xenbus.h Thu Jan 17 14:58:01 2008 +0000
+++ b/extras/mini-os/include/xenbus.h Thu Jan 17 15:08:23 2008 +0000
@@ -12,13 +12,45 @@ void init_xenbus(void);
set to a malloc''d copy of the value. */
char *xenbus_read(xenbus_transaction_t xbt, const char *path, char **value);
-char *xenbus_watch_path(xenbus_transaction_t xbt, const char *path);
-void wait_for_watch(void);
-char* xenbus_wait_for_value(const char*,const char*);
+/* Watch event queue */
+struct xenbus_event {
+ /* Keep these two as this for xs.c */
+ char *path;
+ char *token;
+ struct xenbus_event *next;
+};
+
+char *xenbus_watch_path_token(xenbus_transaction_t xbt, const char *path, const
char *token, struct xenbus_event *volatile *events);
+char *xenbus_unwatch_path_token(xenbus_transaction_t xbt, const char *path,
const char *token);
+extern struct wait_queue_head xenbus_watch_queue;
+void xenbus_wait_for_watch(void);
+char **xenbus_wait_for_watch_return(void);
+char* xenbus_wait_for_value(const char *path, const char *value);
+
+/* When no token is provided, use a global queue. */
+#define XENBUS_WATCH_PATH_TOKEN "xenbus_watch_path"
+extern struct xenbus_event * volatile xenbus_events;
+#define xenbus_watch_path(xbt, path) xenbus_watch_path_token(xbt, path,
XENBUS_WATCH_PATH_TOKEN, NULL)
+#define xenbus_unwatch_path(xbt, path) xenbus_unwatch_path_token(xbt, path,
XENBUS_WATCH_PATH_TOKEN)
+
/* Associates a value with a path. Returns a malloc''d error string on
failure. */
char *xenbus_write(xenbus_transaction_t xbt, const char *path, const char
*value);
+
+struct write_req {
+ const void *data;
+ unsigned len;
+};
+
+/* Send a message to xenbus, in the same fashion as xb_write, and
+ block waiting for a reply. The reply is malloced and should be
+ freed by the caller. */
+struct xsd_sockmsg *
+xenbus_msg_reply(int type,
+ xenbus_transaction_t trans,
+ struct write_req *io,
+ int nr_reqs);
/* Removes the value associated with a path. Returns a malloc''d error
string on failure. */
@@ -52,4 +84,9 @@ char *xenbus_transaction_end(xenbus_tran
/* Read path and parse it as an integer. Returns -1 on error. */
int xenbus_read_integer(char *path);
+/* Contraction of snprintf and xenbus_write(path/node). */
+char* xenbus_printf(xenbus_transaction_t xbt,
+ char* node, char* path,
+ char* fmt, ...);
+
#endif /* XENBUS_H__ */
diff -r 33d1c7f9217a -r 112c1180720c extras/mini-os/netfront.c
--- a/extras/mini-os/netfront.c Thu Jan 17 14:58:01 2008 +0000
+++ b/extras/mini-os/netfront.c Thu Jan 17 15:08:23 2008 +0000
@@ -26,20 +26,6 @@ struct net_info {
} net_info;
-
-char* xenbus_printf(xenbus_transaction_t xbt,
- char* node,char* path,
- char* fmt,unsigned int arg)
-{
- char fullpath[256];
- char val[256];
-
- sprintf(fullpath,"%s/%s",node,path);
- sprintf(val,fmt,arg);
- xenbus_write(xbt,fullpath,val);
-
- return NULL;
-}
#define NET_TX_RING_SIZE __RING_SIZE((struct netif_tx_sring *)0, PAGE_SIZE)
diff -r 33d1c7f9217a -r 112c1180720c extras/mini-os/xenbus/xenbus.c
--- a/extras/mini-os/xenbus/xenbus.c Thu Jan 17 14:58:01 2008 +0000
+++ b/extras/mini-os/xenbus/xenbus.c Thu Jan 17 15:08:23 2008 +0000
@@ -43,7 +43,14 @@
static struct xenstore_domain_interface *xenstore_buf;
static DECLARE_WAIT_QUEUE_HEAD(xb_waitq);
-static DECLARE_WAIT_QUEUE_HEAD(watch_queue);
+DECLARE_WAIT_QUEUE_HEAD(xenbus_watch_queue);
+
+struct xenbus_event *volatile xenbus_events;
+static struct watch {
+ char *token;
+ struct xenbus_event *volatile *events;
+ struct watch *next;
+} *watches;
struct xenbus_req_info
{
int in_use:1;
@@ -68,16 +75,27 @@ static void memcpy_from_ring(const void
memcpy(dest + c1, ring, c2);
}
-void wait_for_watch(void)
+char **xenbus_wait_for_watch_return()
{
+ struct xenbus_event *event;
DEFINE_WAIT(w);
- add_waiter(w,watch_queue);
- schedule();
+ while (!(event = xenbus_events)) {
+ add_waiter(w, xenbus_watch_queue);
+ schedule();
+ }
remove_waiter(w);
- wake(current);
+ xenbus_events = event->next;
+ return &event->path;
}
-char* xenbus_wait_for_value(const char* path,const char* value)
+void xenbus_wait_for_watch(void)
+{
+ char **ret;
+ ret = xenbus_wait_for_watch_return();
+ free(ret);
+}
+
+char* xenbus_wait_for_value(const char* path, const char* value)
{
for(;;)
{
@@ -91,7 +109,7 @@ char* xenbus_wait_for_value(const char*
free(res);
if(r==0) break;
- else wait_for_watch();
+ else xenbus_wait_for_watch();
}
return NULL;
}
@@ -129,20 +147,32 @@ static void xenbus_thread_func(void *ign
if(msg.type == XS_WATCH_EVENT)
{
- char* payload = (char*)malloc(sizeof(msg) + msg.len);
- char *path,*token;
+ struct xenbus_event *event = malloc(sizeof(*event) + msg.len),
+ *volatile *events = NULL;
+ char *data = (char*)event + sizeof(*event);
+ struct watch *watch;
memcpy_from_ring(xenstore_buf->rsp,
- payload,
- MASK_XENSTORE_IDX(xenstore_buf->rsp_cons),
- msg.len + sizeof(msg));
+ data,
+ MASK_XENSTORE_IDX(xenstore_buf->rsp_cons + sizeof(msg)),
+ msg.len);
- path = payload + sizeof(msg);
- token = path + strlen(path) + 1;
+ event->path = data;
+ event->token = event->path + strlen(event->path) + 1;
xenstore_buf->rsp_cons += msg.len + sizeof(msg);
- free(payload);
- wake_up(&watch_queue);
+
+ for (watch = watches; watch; watch = watch->next)
+ if (!strcmp(watch->token, event->token)) {
+ events = watch->events;
+ break;
+ }
+ if (!events)
+ events = &xenbus_events;
+
+ event->next = *events;
+ *events = event;
+ wake_up(&xenbus_watch_queue);
}
else
@@ -230,11 +260,6 @@ void init_xenbus(void)
DEBUG("xenbus on irq %d\n", err);
}
-struct write_req {
- const void *data;
- unsigned len;
-};
-
/* Send data to xenbus. This can block. All of the requests are seen
by xenbus as if sent atomically. The header is added
automatically, using type %type, req_id %req_id, and trans_id
@@ -316,7 +341,7 @@ static void xb_write(int type, int req_i
/* Send a mesasge to xenbus, in the same fashion as xb_write, and
block waiting for a reply. The reply is malloced and should be
freed by the caller. */
-static struct xsd_sockmsg *
+struct xsd_sockmsg *
xenbus_msg_reply(int type,
xenbus_transaction_t trans,
struct write_req *io,
@@ -437,23 +462,55 @@ char *xenbus_write(xenbus_transaction_t
return NULL;
}
-char* xenbus_watch_path( xenbus_transaction_t xbt, const char *path)
+char* xenbus_watch_path_token( xenbus_transaction_t xbt, const char *path,
const char *token, struct xenbus_event *volatile *events)
{
- /* in the future one could have multiple watch queues, and use
- * the token for demuxing. For now the token is 0. */
-
struct xsd_sockmsg *rep;
struct write_req req[] = {
{path, strlen(path) + 1},
- {"0",2 },
+ {token, strlen(token) + 1},
};
+
+ struct watch *watch = malloc(sizeof(*watch));
+
+ watch->token = strdup(token);
+ watch->events = events;
+ watch->next = watches;
+ watches = watch;
rep = xenbus_msg_reply(XS_WATCH, xbt, req, ARRAY_SIZE(req));
char *msg = errmsg(rep);
if (msg) return msg;
free(rep);
+
+ return NULL;
+}
+
+char* xenbus_unwatch_path_token( xenbus_transaction_t xbt, const char *path,
const char *token)
+{
+ struct xsd_sockmsg *rep;
+
+ struct write_req req[] = {
+ {path, strlen(path) + 1},
+ {token, strlen(token) + 1},
+ };
+
+ struct watch *watch, **prev;
+
+ rep = xenbus_msg_reply(XS_UNWATCH, xbt, req, ARRAY_SIZE(req));
+
+ char *msg = errmsg(rep);
+ if (msg) return msg;
+ free(rep);
+
+ for (prev = &watches, watch = *prev; watch; prev = &watch->next,
watch = *prev)
+ if (!strcmp(watch->token, token)) {
+ free(watch->token);
+ *prev = watch->next;
+ free(watch);
+ break;
+ }
return NULL;
}
@@ -566,6 +623,25 @@ int xenbus_read_integer(char *path)
return t;
}
+char* xenbus_printf(xenbus_transaction_t xbt,
+ char* node, char* path,
+ char* fmt, ...)
+{
+#define BUFFER_SIZE 256
+ char fullpath[BUFFER_SIZE];
+ char val[BUFFER_SIZE];
+ va_list args;
+
+ BUG_ON(strlen(node) + strlen(path) + 1 >= BUFFER_SIZE);
+ sprintf(fullpath,"%s/%s", node, path);
+ va_start(args, fmt);
+ vsprintf(val, fmt, args);
+ va_end(args);
+ xenbus_write(xbt,fullpath,val);
+
+ return NULL;
+}
+
static void do_ls_test(const char *pre)
{
char **dirs;
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