Add a safe strcmp helper function

src/libckpool.c

@@ -1061,6 +1061,27 @@ void b58tobin(char *b58bin, const char *b58)
 	}
 }
 
+/* Does a safe string comparison tolerating zero length and NULL strings */
+int safecmp(const char *a, const char *b)
+{
+	int lena, lenb;
+
+	if (unlikely(!a || !b)) {
+		if (a != b)
+			return -1;
+		return 0;
+	}
+	lena = strlen(a);
+	lenb = strlen(b);
+	if (unlikely(!lena || !lenb)) {
+		if (lena != lenb)
+			return -1;
+		return 0;
+	}
+	return (strcmp(a, b));
+}
+
+
 static const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 
 /* Return a malloced string of *src encoded into mime base 64 */

src/libckpool.h

@@ -414,6 +414,7 @@ bool _hex2bin(void *p, const void *vhexstr, size_t len, const char *file, const
 #define hex2bin(p, vhexstr, len) _hex2bin(p, vhexstr, len, __FILE__, __func__, __LINE__)
 char *http_base64(const char *src);
 void b58tobin(char *b58bin, const char *b58);
+int safecmp(const char *a, const char *b);
 
 void address_to_pubkeytxn(char *pkh, const char *addr);
 int ser_number(uchar *s, int32_t val);