From 524032c291fcb4d8e4b160f4c9c4ec8b5de92db3 Mon Sep 17 00:00:00 2001
From: Jo-Philipp Wich <jow@openwrt.org>
Date: Wed, 4 Sep 2013 17:09:51 +0200
Subject: [PATCH] main: store session data to disk on receipt of SIGUSR1 or
 SIGHUP. On HUP terminate self and re-exec

---
 exec.c              |  2 +-
 include/rpcd/exec.h |  2 ++
 main.c              | 36 +++++++++++++++++++++++++++++++++---
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/exec.c b/exec.c
index a5f6561..3d2ec71 100644
--- a/exec.c
+++ b/exec.c
@@ -50,7 +50,7 @@ rpc_errno_status(void)
 	}
 }
 
-static const char *
+const char *
 rpc_exec_lookup(const char *cmd)
 {
 	struct stat s;
diff --git a/include/rpcd/exec.h b/include/rpcd/exec.h
index 05ba3ca..dca1bad 100644
--- a/include/rpcd/exec.h
+++ b/include/rpcd/exec.h
@@ -78,6 +78,8 @@ struct rpc_exec_context {
 	rpc_exec_done_cb_t finish_cb;
 };
 
+const char *rpc_exec_lookup(const char *cmd);
+
 int rpc_exec(const char **args, rpc_exec_write_cb_t in,
              rpc_exec_read_cb_t out, rpc_exec_read_cb_t err,
              rpc_exec_done_cb_t end, void *priv, struct ubus_context *ctx,
diff --git a/main.c b/main.c
index 7335780..9bebd3e 100644
--- a/main.c
+++ b/main.c
@@ -26,8 +26,34 @@
 #include <rpcd/session.h>
 #include <rpcd/uci.h>
 #include <rpcd/plugin.h>
+#include <rpcd/exec.h>
 
 static struct ubus_context *ctx;
+static bool respawn = false;
+
+static void
+handle_signal(int sig)
+{
+	rpc_session_freeze();
+	uloop_cancelled = true;
+	respawn = (sig == SIGHUP);
+}
+
+static void
+exec_self(int argc, char **argv)
+{
+	int i;
+	const char *cmd = rpc_exec_lookup(argv[0]);
+	char **args = calloc(argc + 1, sizeof(char *));
+
+	if (!cmd || !args)
+		return;
+
+	for (i = 0; i < argc; i++)
+		args[i] = argv[i];
+
+	execv(cmd, (char * const *)args);
+}
 
 int main(int argc, char **argv)
 {
@@ -45,9 +71,8 @@ int main(int argc, char **argv)
 	}
 
 	signal(SIGPIPE, SIG_IGN);
-
-	argc -= optind;
-	argv += optind;
+	signal(SIGHUP,  handle_signal);
+	signal(SIGUSR1, handle_signal);
 
 	uloop_init();
 
@@ -63,9 +88,14 @@ int main(int argc, char **argv)
 	rpc_uci_api_init(ctx);
 	rpc_plugin_api_init(ctx);
 
+	rpc_session_thaw();
+
 	uloop_run();
 	ubus_free(ctx);
 	uloop_done();
 
+	if (respawn)
+		exec_self(argc, argv);
+
 	return 0;
 }