diff mbox series

[v2,08/19] tools/xenstore: replace watch->relative_path with a prefix length

Message ID 20221213160045.28170-9-jgross@suse.com (mailing list archive)
State Superseded
Headers show
Series tools/xenstore: do some cleanup and fixes | expand

Commit Message

Jürgen Groß Dec. 13, 2022, 4 p.m. UTC
Instead of storing a pointer to the path which is prepended to
relative paths in struct watch, just use the length of the prepended
path.

It should be noted that the now removed special case of the
relative path being "" in get_watch_path() can't happen at all.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- don't open code get_watch_path() (Julien Grall)
---
 tools/xenstore/xenstored_watch.c | 27 ++++++++-------------------
 1 file changed, 8 insertions(+), 19 deletions(-)

Comments

Julien Grall Dec. 20, 2022, 7:42 p.m. UTC | #1
Hi Juergen,

On 13/12/2022 16:00, Juergen Gross wrote:
> @@ -313,19 +302,19 @@ const char *dump_state_watches(FILE *fp, struct connection *conn,
>   			       unsigned int conn_id)
>   {
>   	const char *ret = NULL;
> +	const char *watch_path;
>   	struct watch *watch;
>   	struct xs_state_watch sw;
>   	struct xs_state_record_header head;
> -	const char *path;
>   
>   	head.type = XS_STATE_TYPE_WATCH;
>   
>   	list_for_each_entry(watch, &conn->watches, list) {
>   		head.length = sizeof(sw);
>   
> +		watch_path = get_watch_path(watch, watch->node);

It is not clear to me why you call get_watch_path() earlier and also 
rename the variable.

I don't mind the new name, but it doesn't feel like it belongs to this 
patch as the code in duymp_state_watches() would not be changed otherwise.

Cheers,

>   		sw.conn_id = conn_id;
> -		path = get_watch_path(watch, watch->node);
> -		sw.path_length = strlen(path) + 1;
> +		sw.path_length = strlen(watch_path) + 1;
>   		sw.token_length = strlen(watch->token) + 1;
>   		head.length += sw.path_length + sw.token_length;
>   		head.length = ROUNDUP(head.length, 3);
> @@ -334,7 +323,7 @@ const char *dump_state_watches(FILE *fp, struct connection *conn,
>   		if (fwrite(&sw, sizeof(sw), 1, fp) != 1)
>   			return "Dump watch state error";
>   
> -		if (fwrite(path, sw.path_length, 1, fp) != 1)
> +		if (fwrite(watch_path, sw.path_length, 1, fp) != 1)
>   			return "Dump watch path error";
>   		if (fwrite(watch->token, sw.token_length, 1, fp) != 1)
>   			return "Dump watch token error";

Cheers,
Jürgen Groß Jan. 11, 2023, 6:48 a.m. UTC | #2
On 20.12.22 20:42, Julien Grall wrote:
> Hi Juergen,
> 
> On 13/12/2022 16:00, Juergen Gross wrote:
>> @@ -313,19 +302,19 @@ const char *dump_state_watches(FILE *fp, struct 
>> connection *conn,
>>                      unsigned int conn_id)
>>   {
>>       const char *ret = NULL;
>> +    const char *watch_path;
>>       struct watch *watch;
>>       struct xs_state_watch sw;
>>       struct xs_state_record_header head;
>> -    const char *path;
>>       head.type = XS_STATE_TYPE_WATCH;
>>       list_for_each_entry(watch, &conn->watches, list) {
>>           head.length = sizeof(sw);
>> +        watch_path = get_watch_path(watch, watch->node);
> 
> It is not clear to me why you call get_watch_path() earlier and also rename the 
> variable.
> 
> I don't mind the new name, but it doesn't feel like it belongs to this patch as 
> the code in duymp_state_watches() would not be changed otherwise.

Both changes are the result of V1 of the series. Will undo them.


Juergen
diff mbox series

Patch

diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c
index 75748ac109..5c0f764781 100644
--- a/tools/xenstore/xenstored_watch.c
+++ b/tools/xenstore/xenstored_watch.c
@@ -39,8 +39,8 @@  struct watch
 	/* Current outstanding events applying to this watch. */
 	struct list_head events;
 
-	/* Is this relative to connnection's implicit path? */
-	const char *relative_path;
+	/* Offset into path for skipping prefix (used for relative paths). */
+	unsigned int prefix_len;
 
 	char *token;
 	char *node;
@@ -66,15 +66,7 @@  static bool is_child(const char *child, const char *parent)
 
 static const char *get_watch_path(const struct watch *watch, const char *name)
 {
-	const char *path = name;
-
-	if (watch->relative_path) {
-		path += strlen(watch->relative_path);
-		if (*path == '/') /* Could be "" */
-			path++;
-	}
-
-	return path;
+	return name + watch->prefix_len;
 }
 
 /*
@@ -211,10 +203,7 @@  static struct watch *add_watch(struct connection *conn, char *path, char *token,
 			      no_quota_check))
 		goto nomem;
 
-	if (relative)
-		watch->relative_path = get_implicit_path(conn);
-	else
-		watch->relative_path = NULL;
+	watch->prefix_len = relative ? strlen(get_implicit_path(conn)) + 1 : 0;
 
 	INIT_LIST_HEAD(&watch->events);
 
@@ -313,19 +302,19 @@  const char *dump_state_watches(FILE *fp, struct connection *conn,
 			       unsigned int conn_id)
 {
 	const char *ret = NULL;
+	const char *watch_path;
 	struct watch *watch;
 	struct xs_state_watch sw;
 	struct xs_state_record_header head;
-	const char *path;
 
 	head.type = XS_STATE_TYPE_WATCH;
 
 	list_for_each_entry(watch, &conn->watches, list) {
 		head.length = sizeof(sw);
 
+		watch_path = get_watch_path(watch, watch->node);
 		sw.conn_id = conn_id;
-		path = get_watch_path(watch, watch->node);
-		sw.path_length = strlen(path) + 1;
+		sw.path_length = strlen(watch_path) + 1;
 		sw.token_length = strlen(watch->token) + 1;
 		head.length += sw.path_length + sw.token_length;
 		head.length = ROUNDUP(head.length, 3);
@@ -334,7 +323,7 @@  const char *dump_state_watches(FILE *fp, struct connection *conn,
 		if (fwrite(&sw, sizeof(sw), 1, fp) != 1)
 			return "Dump watch state error";
 
-		if (fwrite(path, sw.path_length, 1, fp) != 1)
+		if (fwrite(watch_path, sw.path_length, 1, fp) != 1)
 			return "Dump watch path error";
 		if (fwrite(watch->token, sw.token_length, 1, fp) != 1)
 			return "Dump watch token error";