Make xenstored use tdb, transactions can soft-fail (EAGAIN)

Transactions no longer take root dir, no longer lock & block: commit can fail spuriously with EAGAIN, not ETIMEDOUT.
Speeds up transactions by over 1000 times, should be NFS safe.
New program: xs_tdb_dump to dump raw TDB contents.
Don't do failure testing: we are no longer robust against all ENOMEM 8(
Introduce "struct node" which contains perms, children and data.
Make struct xs_permissions unpadded, so we can write to tdb w/o valgrind complaints.
Gently modify TDB to use talloc, not do alloc on tdb_delete.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 7 insertions, 18 deletions

diff --git a/tools/xenstore/xs_lib.c b/tools/xenstore/xs_lib.c
index 5eb7fada6e..a469578993 100644
--- a/tools/xenstore/xs_lib.c
+++ b/tools/xenstore/xs_lib.c
@@ -50,6 +50,13 @@ static const char *xs_daemon_path(void)
 	return buf;
 }
 
+const char *xs_daemon_tdb(void)
+{
+	static char buf[PATH_MAX];
+	sprintf(buf, "%s/tdb", xs_daemon_rootdir());
+	return buf;
+}
+
 const char *xs_daemon_socket(void)
 {
 	return xs_daemon_path();
@@ -66,24 +73,6 @@ const char *xs_daemon_socket_ro(void)
 	return buf;
 }
 
-const char *xs_daemon_store(void)
-{
-	static char buf[PATH_MAX];
-	if (snprintf(buf, PATH_MAX, "%s/store",
-		     xs_daemon_rootdir()) >= PATH_MAX)
-		return NULL;
-	return buf;
-}
-
-const char *xs_daemon_transactions(void)
-{
-	static char buf[PATH_MAX];
-	if (snprintf(buf, PATH_MAX, "%s/transactions",
-		     xs_daemon_rootdir()) >= PATH_MAX)
-		return NULL;
-	return buf;
-}
-
 const char *xs_domain_dev(void)
 {
 	char *s = getenv("XENSTORED_PATH");