add a helper to dup the lxc arguments

src/lxc/arguments.c

@@ -201,3 +201,46 @@ error:
 		lxc_error(args, "could not parse command line");
 	return ret;
 }
+
+extern char **lxc_arguments_dup(const char *file, struct lxc_arguments *args)
+{
+	char **argv;
+	int opt, nbargs = args->argc + 2;
+
+	if (args->log_file)
+		nbargs += 2;
+	if (args->log_priority)
+		nbargs += 2;
+	if (args->quiet)
+		nbargs += 1;
+
+	argv = malloc(nbargs * sizeof(*argv));
+	if (!argv)
+		return NULL;
+
+	nbargs = 0;
+
+	argv[nbargs++] = strdup(file);
+
+	if (args->log_file) {
+		argv[nbargs++] = "--logfile";
+		argv[nbargs++] = strdup(args->log_file);
+	}
+
+	if (args->log_priority) {
+		argv[nbargs++] = "--logpriority";
+		argv[nbargs++] = strdup(args->log_priority);
+	}
+
+	if (args->quiet)
+		argv[nbargs++] = "--quiet";
+
+	argv[nbargs++] = "--";
+
+	for (opt = 0; opt < args->argc; opt++)
+		argv[nbargs++] = strdup(args->argv[opt]);
+
+	argv[nbargs] = NULL;
+
+	return argv;
+}

src/lxc/arguments.h

@@ -73,8 +73,11 @@ struct lxc_arguments {
 /* option keys for long only options */
 #define	OPT_USAGE 0x1000
 
-extern int lxc_arguments_parse(struct lxc_arguments *a_args,
+extern int lxc_arguments_parse(struct lxc_arguments *args,
 			       int argc, char *const argv[]);
+
+extern char **lxc_arguments_dup(const char *file, struct lxc_arguments *args);
+
 extern const char *lxc_strerror(int errnum);
 
 #define lxc_error(arg, fmt, args...) if (!(arg)->quiet)			\