From f002c8a7655e42a325ef6bad9fb0844fad4e410b Mon Sep 17 00:00:00 2001
From: Serge Hallyn <serge.hallyn@ubuntu.com>
Date: Mon, 3 Jun 2013 18:19:01 +0200
Subject: [PATCH] lxc_create: support 'lxc-create -t <template> -h'

With the lxc-create script, 'lxc-create -t template -h' used to call
'template -h' to get template-specific help.  The api based lxc-create
did not yet support that.

Add a 'helpfn' method to the lxc_arguments, which is called at the end
of printhelp, and passed the lxc_arguments.  Use that in lxc_create to
reintroduce the desired behavior.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
---
 src/lxc/arguments.c  |  2 ++
 src/lxc/arguments.h  |  1 +
 src/lxc/lxc_create.c | 27 +++++++++++++++++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/src/lxc/arguments.c b/src/lxc/arguments.c
index 8a8d3067e..90fbea3a3 100644
--- a/src/lxc/arguments.c
+++ b/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);
 }
 
diff --git a/src/lxc/arguments.h b/src/lxc/arguments.h
index b01bd0826..3d1df70b8 100644
--- a/src/lxc/arguments.h
+++ b/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;
diff --git a/src/lxc/lxc_create.c b/src/lxc/lxc_create.c
index f35a664b5..c9231effa 100644
--- a/src/lxc/lxc_create.c
+++ b/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\
-- 
2.47.3