[SCM] Samba Shared Repository - branch master updated

[Michael Adam]

The branch, master has been updated
       via  a752bbd... s3:registry: eliminate race condition in creating/scanning sorted subkeys
      from  09f3ed1... s3:make "net conf addshare" atomic by wrapping all writes in one transaction

http://gitweb.samba.org/?p=samba.git;a=shortlog;h=master


- Log -----------------------------------------------------------------
commit a752bbd10d661ebc93b8d51bd583eb62eb00ad18
Author: Michael Adam <obnox at samba.org>
Date:   Mon Feb 8 11:01:47 2010 +0100

    s3:registry: eliminate race condition in creating/scanning sorted subkeys
    
    Called, from key_exists, scan_sorted_subkeys re-creates the sorted
    subkeys record of the given key and then searches through it.
    The race is that between creation and parsing of the sorted subkey
    record, another process that stores some other subkey of the same
    parent key will delete the sorted subkey record, resulting in an
    WERR_BADFILE of an operation that should actually succeed.
    
    This patch fixes the issue by wrapping the creation and parsing
    into a transaction.
    
    Michael

-----------------------------------------------------------------------

Summary of changes:
 source3/registry/reg_backend_db.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)


Changeset truncated at 500 lines:

diff --git a/source3/registry/reg_backend_db.c b/source3/registry/reg_backend_db.c
index 43963db..fe15b4e 100644
--- a/source3/registry/reg_backend_db.c
+++ b/source3/registry/reg_backend_db.c
@@ -1368,14 +1368,31 @@ static bool scan_parent_subkeys(struct db_context *db, const char *parent,
 	if (state.scanned) {
 		result = state.found;
 	} else {
+		res = db->transaction_start(db);
+		if (res != 0) {
+			DEBUG(0, ("error starting transacion\n"));
+			goto fail;
+		}
+
 		if (!create_sorted_subkeys(path, key)) {
+			res = db->transaction_cancel(db);
+			if (res != 0) {
+				smb_panic("Failed to cancel transaction.");
+			}
 			goto fail;
 		}
+
 		res = db->parse_record(db, string_term_tdb_data(key),
 				       parent_subkey_scanner, &state);
 		if ((res == 0) && (state.scanned)) {
 			result = state.found;
 		}
+
+		res = db->transaction_commit(db);
+		if (res != 0) {
+			DEBUG(0, ("error committing transaction\n"));
+			result = false;
+		}
 	}
 
  fail:


-- 
Samba Shared Repository