Allow invalid sync DBs to be returned by the library

They are placeholders, but important for things like trying to re-sync a
database missing a signature. By using the alpm_db_validity() method at
the right time, a client can take the appropriate action with these
invalid databases as necessary.

In pacman's case, we disallow just about anything that involves looking
at a sync database outside of an '-Sy' operation (although we do check
the validity immediately after). A few operations are still permitted-
'-Q' ops that don't touch sync databases as well as '-R'.

Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/libalpm/sync.c b/lib/libalpm/sync.c
index 783c7280..1d712797 100644
--- a/lib/libalpm/sync.c
+++ b/lib/libalpm/sync.c
@@ -315,6 +315,14 @@ int _alpm_sync_prepare(alpm_handle_t *handle, alpm_list_t **data)
 		*data = NULL;
 	}
 
+	/* ensure all sync database are valid since we will be using them */
+	for(i = handle->dbs_sync; i; i = i->next) {
+		const alpm_db_t *db = i->data;
+		if(!(db->status & DB_STATUS_VALID)) {
+			RET_ERR(handle, ALPM_ERR_DB_INVALID, -1);
+		}
+	}
+
 	if(!(trans->flags & ALPM_TRANS_FLAG_NODEPS)) {
 		alpm_list_t *resolved = NULL; /* target list after resolvedeps */