From: Nick Mathewson <nickm@torproject.org>
Date: Mon, 2 Nov 2009 19:30:25 +0000 (+0000)
Subject: Fix a major parenthesis bug in EVUTIL_UPCAST.
X-Git-Tag: release-2.0.3-alpha~56
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=8283b2f0dcba87974db767e4838434896a92d402;p=libevent

Fix a major parenthesis bug in EVUTIL_UPCAST.

Fortunately, this didn't hurt anything previously, since we had no actual users of the macro where the offset of the base type wasn't 0.

svn:r1488
---

diff --git a/test/regress_util.c b/test/regress_util.c
index 52a43913..0ca2b067 100644
--- a/test/regress_util.c
+++ b/test/regress_util.c
@@ -465,6 +465,30 @@ end:
 	;
 }
 
+struct example_struct {
+	long a;
+	const char *b;
+	long c;
+};
+
+static void
+test_evutil_upcast(void *arg)
+{
+	struct example_struct es1;
+	const char **cp;
+	es1.a = 5;
+	es1.b = "Hello";
+	es1.c = -99;
+
+	tt_int_op(evutil_offsetof(struct example_struct, b), ==, sizeof(long));
+
+	cp = &es1.b;
+	tt_ptr_op(EVUTIL_UPCAST(cp, struct example_struct, b), ==, &es1);
+
+end:
+	;
+
+}
 
 struct testcase_t util_testcases[] = {
 	{ "ipv4_parse", regress_ipv4_parse, 0, NULL, NULL },
@@ -475,6 +499,7 @@ struct testcase_t util_testcases[] = {
 	{ "evutil_casecmp", test_evutil_casecmp, 0, NULL, NULL },
 	{ "strlcpy", test_evutil_strlcpy, 0, NULL, NULL },
 	{ "log", test_evutil_log, TT_FORK, NULL, NULL },
+	{ "upcast", test_evutil_upcast, 0, NULL, NULL },
 	END_OF_TESTCASES,
 };
 
diff --git a/util-internal.h b/util-internal.h
index 853f2200..dc112116 100644
--- a/util-internal.h
+++ b/util-internal.h
@@ -130,7 +130,7 @@ extern const char EVUTIL_TOLOWER_TABLE[];
     }
  */
 #define EVUTIL_UPCAST(ptr, type, field)				\
-	((type *)((char*)ptr) - evutil_offsetof(type, field))
+	((type *)(((char*)(ptr)) - evutil_offsetof(type, field)))
 
 
 int evutil_socket_connect(evutil_socket_t *fd_ptr, struct sockaddr *sa, int socklen);