Make the sqlite3_filename_xxxx() interfaces robust against NULL pointer

arguments, even though the documentation says the behavior is undefined
in that case.

FossilOrigin-Name: dd64c60bab4e2b44419db6882dfcc80b73d733ebe3bea64a7588c33fbc428234

1 files changed, 3 insertions, 1 deletions

diff --git a/src/main.c b/src/main.c
index 65fe4a668..c44b9b470 100644
--- a/src/main.c
+++ b/src/main.c
@@ -4487,9 +4487,11 @@ sqlite3_int64 sqlite3_uri_int64(
 ** corruption.
 */
 const char *sqlite3_filename_database(const char *zFilename){
+  if( zFilename==0 ) return 0;
   return databaseName(zFilename);
 }
 const char *sqlite3_filename_journal(const char *zFilename){
+  if( zFilename==0 ) return 0;
   zFilename = databaseName(zFilename);
   zFilename += sqlite3Strlen30(zFilename) + 1;
   while( zFilename[0] ){
@@ -4503,7 +4505,7 @@ const char *sqlite3_filename_wal(const char *zFilename){
   return 0;
 #else
   zFilename = sqlite3_filename_journal(zFilename);
-  zFilename += sqlite3Strlen30(zFilename) + 1;
+  if( zFilename ) zFilename += sqlite3Strlen30(zFilename) + 1;
   return zFilename;
 #endif
 }