[pacman-dev] [PATCHv2] be_sync: avoid crashing on files in the root of a DB

[Dave Reisner]

If a sync DB is malformed and contains entries in the root of the
archive, load_pkg_for_entry will leave the 'filename' variable empty,
leading to a crash in the ensuing strcmp() calls which determine the DB
fragment being examined.

While this isn't a read error, this should be reported to the user so
that it can be addressed by the creator of the DB. This change promotes
the same pre-existing debug statement to a warning as well so that all
DB abnormalities are surfaced by the frontend.

As seen: https://bbs.archlinux.org/viewtopic.php?pid=1297766

Signed-off-by: Dave Reisner <dreisner at archlinux.org>
---
v2: promote debug statements to warnings, add gettext wrapper

 lib/libalpm/be_sync.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/libalpm/be_sync.c b/lib/libalpm/be_sync.c
index feda6f5..21e36fe 100644
--- a/lib/libalpm/be_sync.c
+++ b/lib/libalpm/be_sync.c
@@ -561,6 +561,14 @@ static int sync_db_read(alpm_db_t *db, struct archive *archive,
 		return -1;
 	}
 
+	if(filename == NULL) {
+		/* A file exists outside of a subdirectory. This isn't a read error, so return
+		 * success and try to continue on. */
+		_alpm_log(db->handle, ALPM_LOG_WARNING, _("unknown database file: %s\n"),
+				filename);
+		return 0;
+	}
+
 	if(strcmp(filename, "desc") == 0 || strcmp(filename, "depends") == 0
 			|| (strcmp(filename, "deltas") == 0 && db->handle->deltaratio > 0.0) ) {
 		int ret;
@@ -657,7 +665,8 @@ static int sync_db_read(alpm_db_t *db, struct archive *archive,
 		/* currently do nothing with this file */
 	} else {
 		/* unknown database file */
-		_alpm_log(db->handle, ALPM_LOG_DEBUG, "unknown database file: %s\n", filename);
+		_alpm_log(db->handle, ALPM_LOG_WARNING, _("unknown database file: %s\n"),
+				filename);
 	}
 
 	return 0;
-- 
1.8.3.2