qdevice: Add vcatf to dynar-str

Signed-off-by: Jan Friesse <jfriesse@redhat.com>

qdevices/dynar-str.c

@@ -59,11 +59,11 @@ dynar_str_cat(struct dynar *dest, const char *str)
 }
 
 int
-dynar_str_catf(struct dynar *dest, const char *format, ...)
+dynar_str_vcatf(struct dynar *dest, const char *format, va_list ap)
 {
 	int to_write;
 	int written;
-	va_list ap;
+	va_list ap_copy;
 	size_t allocated;
 	char buf;
 	char *p;
@@ -71,9 +71,9 @@ dynar_str_catf(struct dynar *dest, const char *format, ...)
 	/*
 	 * Find out how much bytes is needed
 	 */
-	va_start(ap, format);
-	to_write = vsnprintf(&buf, sizeof(buf), format, ap);
-	va_end(ap);
+	va_copy(ap_copy, ap);
+	to_write = vsnprintf(&buf, sizeof(buf), format, ap_copy);
+	va_end(ap_copy);
 
 	if (to_write < 0) {
 		return (-1);
@@ -94,9 +94,9 @@ dynar_str_catf(struct dynar *dest, const char *format, ...)
 
 	p = dynar_data(dest) + dynar_size(dest);
 
-	va_start(ap, format);
-	written = vsnprintf(p, allocated, format, ap);
-	va_end(ap);
+	va_copy(ap_copy, ap);
+	written = vsnprintf(p, allocated, format, ap_copy);
+	va_end(ap_copy);
 
 	if (written >= allocated) {
 		return (-1);
@@ -106,3 +106,16 @@ dynar_str_catf(struct dynar *dest, const char *format, ...)
 
 	return (written);
 }
+
+int
+dynar_str_catf(struct dynar *dest, const char *format, ...)
+{
+	va_list ap;
+	int res;
+
+	va_start(ap, format);
+	res = dynar_str_vcatf(dest, format, ap);
+	va_end(ap);
+
+	return (res);
+}

qdevices/dynar-str.h

@@ -48,6 +48,9 @@ extern int		dynar_str_cat(struct dynar *dest, const char *str);
 extern int		dynar_str_catf(struct dynar *dest, const char *format, ...)
     __attribute__((__format__(__printf__, 2, 3)));
 
+extern int		dynar_str_vcatf(struct dynar *dest, const char *format, va_list ap)
+    __attribute__((__format__(__printf__, 2, 0)));
+
 #ifdef __cplusplus
 }
 #endif