Propagate null gstring through string_catn()

[exim.git] / src / src / lookups / sqlite.c

diff --git a/src/src/lookups/sqlite.c b/src/src/lookups/sqlite.c
index cccaa1b72da5022d1d4231b252e65cf631a3eaf3..d8a11ba1294897001964023c4cafb644381a049b 100644 (file)
--- a/src/src/lookups/sqlite.c
+++ b/src/src/lookups/sqlite.c
@@ -3,6 +3,7 @@
 *************************************************/
 
 /* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 - 2021 */
 /* See the file NOTICE for conditions of use and distribution. */
 
 #include "../exim.h"
@@ -23,16 +24,23 @@ sqlite_open(const uschar * filename, uschar ** errmsg)
 sqlite3 *db = NULL;
 int ret;
 
-if (!filename || !*filename) filename = sqlite_dbfile;
-if (*filename != '/')
+if (!filename || !*filename)
+  {
+  DEBUG(D_lookup) debug_printf_indent("Using sqlite_dbfile: %s\n", sqlite_dbfile);
+  filename = sqlite_dbfile;
+  }
+if (!filename || *filename != '/')
   *errmsg = US"absolute file name expected for \"sqlite\" lookup";
 else if ((ret = sqlite3_open(CCS filename, &db)) != 0)
   {
   *errmsg = (void *)sqlite3_errmsg(db);
+  sqlite3_close(db);
+  db = NULL;
   DEBUG(D_lookup) debug_printf_indent("Error opening database: %s\n", *errmsg);
   }
 
-sqlite3_busy_timeout(db, 1000 * sqlite_lock_timeout);
+if (db)
+  sqlite3_busy_timeout(db, 1000 * sqlite_lock_timeout);
 return db;
 }
 
@@ -58,7 +66,7 @@ if (argc > 1)
   /* For multiple fields, include the field name too */
   for (int i = 0; i < argc; i++)
     {
-    uschar *value = US((argv[i] != NULL)? argv[i]:"<NULL>");
+    uschar * value = US(argv[i] ? argv[i] : "<NULL>");
     res = lf_quote(US azColName[i], value, Ustrlen(value), res);
     }
   }
@@ -66,7 +74,8 @@ if (argc > 1)
 else
   res = string_cat(res, argv[0] ? US argv[0] : US "<NULL>");
 
-*(gstring **)arg = res;
+/* always return a non-null gstring, even for a zero-length string result */
+*(gstring **)arg = res ? res : string_get(1);
 return 0;
 }
 
@@ -86,7 +95,7 @@ if (ret != SQLITE_OK)
   return FAIL;
   }
 
-if (!res) *do_cache = 0;
+if (!res) *do_cache = 0;       /* on fail, wipe cache */
 
 *result = string_from_gstring(res);
 return OK;