X-Git-Url: http://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Fmem%2Fmem.c;h=5eb15070ed3c3f9f5bf8d2dd8b0d0f060ffa1766;hb=HEAD;hp=2dfc72a506209511c0d61901024a470a28472d84;hpb=299170fa67ff3cf664cbcd2c95c4a85d0d6e699d;p=ccan

diff --git a/ccan/mem/mem.c b/ccan/mem/mem.c
index 2dfc72a5..13027a2a 100644
--- a/ccan/mem/mem.c
+++ b/ccan/mem/mem.c
@@ -92,12 +92,37 @@ void memswap(void *a, void *b, size_t n)
 bool memeqzero(const void *data, size_t length)
 {
 	const unsigned char *p = data;
+	size_t len;
 
-	while (length) {
+	/* Check first 16 bytes manually */
+	for (len = 0; len < 16; len++) {
+		if (!length)
+			return true;
 		if (*p)
 			return false;
 		p++;
 		length--;
 	}
-	return true;
+
+	/* Now we know that's zero, memcmp with self. */
+	return memcmp(data, p, length) == 0;
+}
+
+void memtaint(void *data, size_t len)
+{
+	/* Using 16 bytes is a bit quicker than 4 */
+	const unsigned tainter[]
+		= { 0xdeadbeef, 0xdeadbeef, 0xdeadbeef, 0xdeadbeef };
+	char *p = data;
+
+	while (len >= sizeof(tainter)) {
+		memcpy(p, tainter, sizeof(tainter));
+		p += sizeof(tainter);
+		len -= sizeof(tainter);
+	}
+	memcpy(p, tainter, len);
+
+#if HAVE_VALGRIND_MEMCHECK_H
+	VALGRIND_MAKE_MEM_UNDEFINED(data, len);
+#endif
 }