1 files changed, 227 insertions, 0 deletions
diff --git a/server/main.c b/server/main.c
new file mode 100644
index 0000000..5a923a9
--- /dev/null
+++ b/server/main.c
@@ -0,0 +1,227 @@
+/*
+ * server/main.c
+ */
+
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "dnbd2.h"
+#include "tree.h"
+#include "file.h"
+#include "config.h"
+#include "query.h"
+
+
+char *cfile = NULL; /* path to config file */
+void *tree = NULL;  /* tree containing datasets */
+int server_fd;      /* file descriptor for UPD communication */
+struct sockaddr_in server_addr;
+
+
+/*
+ * Flags and signal handlers.
+ */
+int sig_exit, sig_config;
+void exit_handler(int sig);
+void config_handler(int sig);
+
+
+/*
+ * Function to configure server.  We call it with LOAD on
+ * initialization and with RELOAD when SIGHUP is caught.
+ */
+enum config_action { LOAD, RELOAD };
+int configure(enum config_action action);
+
+
+void print_usage(void);
+int daemon_init(void);
+
+
+int main(int argc, char **argv)
+{
+	int ret;
+	ssize_t n;
+	socklen_t len;
+	dnbd2_data_reply_t reply;
+	dnbd2_data_request_t request;
+	struct sockaddr_in client_addr;
+	struct sigaction exit_act, config_act;
+
+	if (argc != 2) {
+		print_usage();
+		return -1;
+	}
+
+	cfile = argv[1];
+	openlog(argv[0], LOG_PID, LOG_LOCAL2);
+	syslog(LOG_NOTICE, "Starting DNBD2 Server.");
+
+	/* Load datasets and bind to socket. */
+	if (configure(LOAD) == -1)
+		goto out_no_start;
+
+	/* Daemonize. */
+	ret = daemon_init();
+	if (ret == -1) {
+		syslog(LOG_ERR, "Could not fork and background.");
+		goto out_no_start;
+	}
+
+	/* Setup signal handlers. */
+	sigaction(SIGTERM, NULL, &exit_act);
+	exit_act.sa_flags &= ~SA_RESTART;
+	exit_act.sa_handler = exit_handler;
+
+	sigaction(SIGHUP, NULL, &config_act);
+	config_act.sa_flags &= ~SA_RESTART;
+	config_act.sa_handler = config_handler;
+
+	sigaction(SIGTERM, &exit_act, NULL);
+	sigaction(SIGINT, &exit_act, NULL);
+	sigaction(SIGHUP, &config_act, NULL);
+
+	while (1) {
+		if (sig_exit) {
+		        syslog(LOG_NOTICE, "Stopping Server.");
+			exit(0);
+		}
+		if (sig_config) {
+			syslog(LOG_NOTICE, "Reloading configuration.");
+			if (configure(RELOAD) == -1)
+				syslog(LOG_ERR, "Not using new configuration.");
+			sig_config = 0;
+		}
+
+		/* Receive request. */
+		len = sizeof(client_addr);
+		n = recvfrom(server_fd, &request, sizeof(request), 0,
+			     &client_addr, &len);
+
+		if (n == -1 || n != sizeof(request))
+			continue;
+
+		/* Process request. */
+		ret = handle_query(&request, &reply, &tree);
+		if (ret == -1)
+			continue;
+
+		/* Send reply. */
+		sendto(server_fd, &reply, sizeof(reply), 0, &client_addr, len);
+	}
+
+	return 0;
+
+ out_no_start:
+        syslog(LOG_ERR, "Server not started.");
+        fprintf(stderr, "Server not started - "
+		"consult your syslog for errors.\n");
+        return -1;
+}
+
+
+void config_handler(int sig)
+{
+	sig_config = 1;
+}
+
+
+void exit_handler(int sig)
+{
+	sig_exit = 1;
+}
+
+
+int cmp_addr(struct sockaddr_in addr1, struct sockaddr_in addr2)
+{
+	int diff = memcmp(&addr1.sin_addr.s_addr,
+			  &addr2.sin_addr.s_addr,
+			  sizeof(in_addr_t));
+
+	if (diff)
+		return diff;
+
+	return memcmp(&addr1.sin_port,
+		      &addr2.sin_port,
+		      sizeof(in_port_t));
+}
+
+
+int configure(enum config_action action)
+{
+	void *tmp_tree = NULL;
+	int datasets, ret, tmp_fd = server_fd;
+	struct sockaddr_in tmp_addr;
+
+	datasets = parse_config_file(cfile, &tmp_addr, &tmp_tree);
+	if (datasets <= 0)
+		return -1;
+
+	/* Create a socket and bind to it. */
+	if (action == LOAD || cmp_addr(tmp_addr, server_addr)) {
+		tmp_fd = socket(PF_INET, SOCK_DGRAM, 0);
+		if (tmp_fd == -1) {
+			syslog(LOG_ERR, "Could not create socket.");
+			return -1;
+		}
+
+		ret = bind(tmp_fd, (struct sockaddr *) &tmp_addr,
+			   sizeof(tmp_addr));
+
+		if (ret == -1) {
+			close(tmp_fd);
+			syslog(LOG_ERR, "Could not assign name to socket.");
+			return -1;
+		}
+	}
+	
+	/* Make new socket available and close the old one if necesary. */
+	if (action == RELOAD && cmp_addr(tmp_addr, server_addr)) {
+		if (close(server_fd) == -1 ) {
+			syslog(LOG_ERR, "Could not close socket.");
+		}
+	}
+
+	server_fd = tmp_fd;
+	server_addr = tmp_addr;
+
+	tree_destroy(tree);
+	tree = tmp_tree;
+	return 0;
+}
+
+
+void print_usage(void)
+{
+	printf("usage: dnbd2-dserver config-file\n");
+}
+
+
+int daemon_init(void)
+{
+	pid_t pid = fork();
+
+	if (pid == -1)
+		return pid;
+
+	if (pid != 0) {
+		/* We are the parent. */
+		exit(0); 
+	}
+
+	/* We are the child. */
+	setsid();
+	chdir("/");
+	umask(0);
+
+	return 0;
+}