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, 2 insertions, 7 deletions

diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c
index e09acee6df..3732781df9 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -309,16 +309,11 @@ void do_introduce(struct connection *conn, struct buffered_data *in)
 		return;
 	}
 
-	if (conn->id != 0) {
+	if (conn->id != 0 || !conn->can_write) {
 		send_error(conn, EACCES);
 		return;
 	}
 
-	if (!conn->can_write) {
-		send_error(conn, EROFS);
-		return;
-	}
-
 	/* Sanity check args. */
 	if ((atoi(vec[2]) <= 0) || !is_valid_nodename(vec[3])) {
 		send_error(conn, EINVAL);
@@ -386,7 +381,7 @@ void do_release(struct connection *conn, const char *domid_str)
 
 	talloc_free(domain->conn);
 
-	fire_watches(NULL, "@releaseDomain", false);
+	fire_watches(conn, "@releaseDomain", false);
 
 	send_ack(conn, XS_RELEASE);
 }