db_hlr: zero-initialize "struct tm"

The last LU time gets read from the database as string, parsed with
strptime to "struct tm", and then gets converted to time_t with mktime.

A recent behavior change in glibc's mktime implementation unconvered,
that we don't have tm.tm_isdst (daylight saving time) set properly. As
"struct tm" was not initialized, and strptime did not write to tm_isdst,
it was set to a random value. When it was not 0, db_test failed on UTC
systems with a more recent glibc (e.g. Ubuntu 19.04).

Fix this by zero-initializing "struct tm" and remove the previous
workaround that made db_test pass on UTC systems.

Related: OS#4026
Change-Id: Iebbbe42fc5cd43324206d9433ede67b39251389c

1 files changed, 1 insertions, 1 deletions

diff --git a/src/db_hlr.c b/src/db_hlr.c
index 362dcf2..694ac53 100644
--- a/src/db_hlr.c
+++ b/src/db_hlr.c
@@ -445,7 +445,7 @@ static int db_sel(struct db_context *dbc, sqlite3_stmt *stmt, struct hlr_subscri
 	int rc;
 	int ret = 0;
 	const char *last_lu_seen_str;
-	struct tm tm;
+	struct tm tm = {0};
 
 	/* execute the statement */
 	rc = sqlite3_step(stmt);