Provide helper functions calloc_str and realloc_strcat to create and extend arbitrary length arrays based on string length.

util.c

@@ -1477,3 +1477,44 @@ void dev_error(struct cgpu_info *dev, enum dev_reason reason)
 	}
 
 }
+
+/* Calloc enough memory to fit string s, rounding up to 4 byte alignment */
+void *calloc_str(char *s)
+{
+	size_t len = strlen(s);
+	void *ptr = NULL;
+
+	if (!len)
+		goto out;
+
+	len += 1;
+	if (len % 4)
+		len += 4 - (len % 4);
+	ptr = calloc(len, 1);
+	if (unlikely(!ptr))
+		quit(1, "Failed to calloc ptr in calloc_str");
+out:
+	return ptr;
+}
+
+/* Realloc an existing string to fit an extra string s, appending s to it. */
+void *realloc_strcat(char *ptr, char *s)
+{
+	size_t old = strlen(ptr), len = strlen(s);
+	char *ret;
+
+	if (!len)
+		return ptr;
+
+	len += old + 1;
+	if (len % 4)
+		len += 4 - (len % 4);
+
+	ret = malloc(len);
+	if (unlikely(!ret))
+		quit(1, "Failed to malloc in realloc_strcat");
+
+	sprintf(ret, "%s%s", ptr, s);
+	free(ptr);
+	return ret;
+}

util.h

@@ -52,5 +52,7 @@ bool extract_sockaddr(struct pool *pool, char *url);
 bool auth_stratum(struct pool *pool);
 bool initiate_stratum(struct pool *pool);
 void dev_error(struct cgpu_info *dev, enum dev_reason reason);
+void *calloc_str(char *s);
+void *realloc_strcat(char *ptr, char *s);
 
 #endif /* __UTIL_H__ */