From 0bcb0478060be52d2bc9c26a3e88bb759f890d74 Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@pond.sub.org>
Date: Tue, 4 Mar 2008 07:55:32 +0100
Subject: [PATCH] Make nstr_exec_val() more robust

Oops on bad argument, and make a better error value then.
---
 include/nsc.h             |  3 +++
 src/lib/common/nstreval.c | 22 +++++++++++-----------
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/include/nsc.h b/include/nsc.h
index 91519206..636e0548 100644
--- a/include/nsc.h
+++ b/include/nsc.h
@@ -67,6 +67,9 @@ typedef enum {
 } nsc_type;
 typedef char packed_nsc_type;
 
+/* Is TYPE a promoted value type?  */
+#define NSC_IS_PROMOTED(type) (NSC_LONG <= (type) && (type) <= NSC_STRING)
+
 /* Return nsc_type for a signed integer with the same size as TYPE.  */
 #define NSC_SITYPE(type)				\
     (sizeof(type) == 1 ? NSC_CHAR			\
diff --git a/src/lib/common/nstreval.c b/src/lib/common/nstreval.c
index c730ff5a..24d9dda0 100644
--- a/src/lib/common/nstreval.c
+++ b/src/lib/common/nstreval.c
@@ -36,6 +36,7 @@
 #include <config.h>
 
 #include <limits.h>
+#include <string.h>
 #include "file.h"
 #include "nat.h"
 #include "nsc.h"
@@ -45,7 +46,7 @@
 /*
  * Evaluate VAL.
  * If VAL is symbolic, evaluate it into a promoted value type.
- * Use coordinate system of country CNUM.
+ * Use country CNUM's coordinate system and access control.
  * PTR points to a context object of the type that was used to compile
  * the value.
  * Unless WANT is NSC_NOTYPE, coerce the value to promoted value type
@@ -60,10 +61,10 @@ nstr_exec_val(struct valstr *val, natid cnum, void *ptr, nsc_type want)
     int idx;
     struct natstr *natp;
 
+    if (CANT_HAPPEN(want != NSC_NOTYPE && !NSC_IS_PROMOTED(want)))
+	want = nstr_promote(want);
+
     switch (val->val_cat) {
-    default:
-	CANT_REACH();
-	/* fall through */
     case NSC_VAL:
 	valtype = val->val_type;
 	break;
@@ -134,6 +135,10 @@ nstr_exec_val(struct valstr *val, natid cnum, void *ptr, nsc_type want)
 	    val->val_as.lng = 0;
 	}
 	val->val_cat = NSC_VAL;
+	break;
+    default:
+	CANT_REACH();
+	valtype = NSC_NOTYPE;
     }
 
     if (valtype == want)
@@ -147,14 +152,9 @@ nstr_exec_val(struct valstr *val, natid cnum, void *ptr, nsc_type want)
 	CANT_REACH();		/* FIXME implement */
 
     if (CANT_HAPPEN(valtype != want && want != NSC_NOTYPE)) {
+	/* make up an error value */
 	valtype = want;
-	switch (want) {
-	case NSC_LONG: val->val_as.lng = 0; break;
-	case NSC_DOUBLE: val->val_as.dbl = 0.0; break;
-	case NSC_STRING: val->val_as.str.base = NULL; break;
-	default:
-	    CANT_REACH();
-	}
+	memset(&val->val_as, 0, sizeof(val->val_as));
     }
 
     val->val_type = valtype;