lxc_create: support 'lxc-create -t <template> -h'

src/lxc/arguments.c

@@ -147,6 +147,8 @@ for any corresponding short options.\n\
 See the %s man page for further information.\n\n",
 	args->progname, args->help, args->progname);
 
+	if (args->helpfn)
+		args->helpfn(args);
 	exit(code);
 }
 

src/lxc/arguments.h

@@ -33,6 +33,7 @@ typedef int (*lxc_arguments_checker_t) (const struct lxc_arguments *);
 
 struct lxc_arguments {
 	const char *help;
+	void(*helpfn)(const struct lxc_arguments *);
 	const char *progname;
 	const struct option* options;
 	lxc_arguments_parser_t parser;

src/lxc/lxc_create.c

@@ -85,8 +85,35 @@ static const struct option my_longopts[] = {
 	LXC_COMMON_OPTIONS
 };
 
+static void create_helpfn(const struct lxc_arguments *args) {
+	char *argv[3], *path;
+	size_t len;
+	int ret;
+	pid_t pid;
+
+	if (!args->template)
+		return;
+	if ((pid = fork()) < 0)
+		return;
+	if (pid)
+		wait_for_pid(pid);
+	len = strlen(LXCTEMPLATEDIR) + strlen(args->template) + strlen("/lxc-") + 1;
+	path = alloca(len);
+	ret = snprintf(path, len,  "%s/lxc-%s", LXCTEMPLATEDIR, args->template);
+	if (ret < 0 || ret >= len)
+		return;
+
+	argv[0] = path;
+	argv[1] = "-h";
+	argv[2] = NULL;
+	execv(path, argv);
+	ERROR("Error executing %s -h", path);
+	exit(1);
+}
+
 static struct lxc_arguments my_args = {
 	.progname = "lxc-create",
+	.helpfn   = create_helpfn,
 	.help     = "\
 --name=NAME [-w] [-r] [-t timeout] [-P lxcpath]\n\
 \n\