Provide a lower level __bin2hex function that does not allocate memory itself.

miner.h

@@ -952,6 +952,7 @@ extern json_t *json_rpc_call(CURL *curl, const char *url, const char *userpass,
 #endif
 extern const char *proxytype(proxytypes_t proxytype);
 extern char *get_proxy(char *url, struct pool *pool);
+extern void __bin2hex(char *s, const unsigned char *p, size_t len);
 extern char *bin2hex(const unsigned char *p, size_t len);
 extern bool hex2bin(unsigned char *p, const char *hexstr, size_t len);
 

util.c

@@ -584,6 +584,16 @@ char *get_proxy(char *url, struct pool *pool)
 	return url;
 }
 
+/* Adequate size s==len*2 + 1 must be alloced to use this variant */
+void __bin2hex(char *s, const unsigned char *p, size_t len)
+{
+	int i;
+
+	for (i = 0; i < (int)len; i++)
+		sprintf(s + (i * 2), "%02x", (unsigned int)p[i]);
+
+}
+
 /* Returns a malloced array string of a binary value of arbitrary length. The
  * array is rounded up to a 4 byte size to appease architectures that need
  * aligned array  sizes */
@@ -591,7 +601,6 @@ char *bin2hex(const unsigned char *p, size_t len)
 {
 	ssize_t slen;
 	char *s;
-	int i;
 
 	slen = len * 2 + 1;
 	if (slen % 4)
@@ -600,8 +609,7 @@ char *bin2hex(const unsigned char *p, size_t len)
 	if (unlikely(!s))
 		quithere(1, "Failed to calloc");
 
-	for (i = 0; i < (int)len; i++)
-		sprintf(s + (i * 2), "%02x", (unsigned int)p[i]);
+	__bin2hex(s, p, len);
 
 	return s;
 }