[SERVER] Reload configuration at runtime

1 files changed, 117 insertions, 0 deletions

diff --git a/src/server/utils.c b/src/server/utils.c
new file mode 100644
index 0000000..e0bbecf
--- /dev/null
+++ b/src/server/utils.c
@@ -0,0 +1,117 @@
+/*
+ * This file is part of the Distributed Network Block Device 3
+ *
+ * Copyright(c) 2011-2012 Johann Latocha <johann@latocha.de>
+ *
+ * This file may be licensed under the terms of of the
+ * GNU General Public License Version 2 (the ``GPL'').
+ *
+ * Software distributed under the License is distributed
+ * on an ``AS IS'' basis, WITHOUT WARRANTY OF ANY KIND, either
+ * express or implied. See the GPL for the specific language
+ * governing rights and limitations.
+ *
+ * You should have received a copy of the GPL along with this
+ * program. If not, go to http://www.gnu.org/licenses/gpl.html
+ * or write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "utils.h"
+#include "hashtable.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+
+void write_pid_file(pid_t pid)
+{
+	FILE *f = fopen(SERVER_PID_FILE, "w");
+	if(f != NULL)
+	{
+	    fprintf(f, "%i", pid);
+	    fclose(f);
+	}
+	else
+	{
+		printf("ERROR: Couldn't write pid file (%s).\n", SERVER_PID_FILE);
+	}
+}
+
+pid_t read_pid_file()
+{
+	pid_t pid = 0;
+
+	FILE *f = fopen(SERVER_PID_FILE, "r");
+	if(f != NULL)
+	{
+	    fscanf(f, "%i", &pid);
+	    fclose(f);
+	}
+	else
+	{
+		printf("ERROR: Couldn't read pid file (%s).\n", SERVER_PID_FILE);
+	}
+
+	return pid;
+}
+
+void delete_pid_file()
+{
+	 if (unlink(SERVER_PID_FILE) != 0)
+	 {
+		 printf("ERROR: Couldn't delete pid file (%s).\n", SERVER_PID_FILE);
+	 }
+}
+
+
+void load_config(char* config_file_name)
+{
+	ht_create();
+	FILE *config_file = fopen(config_file_name, "r");
+
+	if (config_file == NULL)
+	{
+		printf("ERROR: Config file not found: %s\n", config_file_name);
+		exit(EXIT_FAILURE);
+	}
+
+	char line[MAX_FILE_NAME + 1 + MAX_FILE_ID];
+	char* image_name = NULL;
+	char* image_id = NULL;
+
+	while (fgets(line, sizeof(line), config_file) != NULL)
+	{
+		sscanf(line, "%as %as", &image_name, &image_id);
+		if (ht_insert(image_id, image_name) < 0)
+		{
+			printf("ERROR: Image name or ID is too big\n");
+			exit(EXIT_FAILURE);
+		}
+	}
+	fclose(config_file);
+}
+
+void reload_config(char* config_file_name)
+{
+	ht_destroy();
+	load_config(config_file_name);
+}
+
+void send_signal(int signum)
+{
+	pid_t pid = read_pid_file();
+	if (pid != 0)
+	{
+		if (kill(pid, signum) != 0)
+		{
+			printf("ERROR: dnbd3-server is not running\n");
+			delete_pid_file();
+		}
+	}
+	else
+	{
+		printf("ERROR: dnbd3-server is not running\n");
+	}
+}