Daemonize BESS

- By default bessd now starts daemonized.
- Use -w to run without daemonization.
- When daemonized output goes to syslogd

Author: apanda

core/main.c

@@ -1,5 +1,6 @@
 #include <assert.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <fcntl.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -13,6 +14,7 @@
 #include "master.h"
 #include "worker.h"
 #include "driver.h"
+#include "syslog.h"
 
 #if 0
 #include "old_modules/vport_guest_sndrv.h"
@@ -908,6 +910,8 @@ static struct {
 	uint16_t port;
 } cmdline_opts;
 
+static int daemonize = 1;
+
 static void parse_core_list()
 {
 	char *ptr;
@@ -939,6 +943,8 @@ static void print_usage(char *exec_name)
 	fprintf(stderr, "  %-16s Specifies the TCP port on which SoftNIC listens"
 			     "for controller connections\n",
 			"-p <port>");
+	fprintf(stderr, "  %-16s Do not daemonize BESS",
+			"-w");
 
 	exit(2);
 }
@@ -951,7 +957,7 @@ static void init_config(int argc, char **argv)
 
 	num_workers = 0;
 
-	while ((c = getopt(argc, argv, ":tc:p:")) != -1) {
+	while ((c = getopt(argc, argv, ":tc:p:w")) != -1) {
 		switch (c) {
 		case 't':
 			dump_types();
@@ -965,6 +971,9 @@ static void init_config(int argc, char **argv)
 		case 'p':
 			sscanf(optarg, "%hu", &cmdline_opts.port);
 			break;
+		case 'w':
+			daemonize = 0;
+			break;
 
 		case ':':
 			fprintf(stderr, "argument is required for -%c\n", 
@@ -991,7 +1000,30 @@ static void init_config(int argc, char **argv)
 
 int main(int argc, char **argv)
 {
+	pid_t pid, sid;
 	init_config(argc, argv);
+
+	if (daemonize) {
+		pid = fork();
+		if (pid < 0) {
+			fprintf(stderr, "Could not fork damon\n");
+			exit(EXIT_FAILURE);
+		}
+		if (pid > 0) {
+			exit(EXIT_SUCCESS);
+		}
+		// Reparent
+		sid = setsid();
+		if (sid < 0) {
+			fprintf(stderr, "Could not set SID\n");
+			exit(EXIT_FAILURE);
+		}
+
+		close(STDIN_FILENO);
+		close(STDERR_FILENO);
+		close(STDOUT_FILENO);
+		setup_syslog();
+	}
 	init_dpdk(argv[0]);
 	init_mempool();
 	init_drivers();
@@ -1005,5 +1037,8 @@ int main(int argc, char **argv)
 	rte_eal_mp_wait_lcore();
 	close_mempool();
 
+	if (daemonize)
+		end_syslog();
+
 	return 0;
 }

core/syslog.h

@@ -0,0 +1,44 @@
+#include <syslog.h>
+#ifndef __SYSLOG_H__
+#define __SYSLOG_H__
+static ssize_t stdout_writer(void *cookie, const char *data, size_t len)
+{
+	syslog(LOG_INFO, "%.*s", (int)len, data);
+	return  len;
+}
+
+static ssize_t stderr_writer(void *cookie, const char *data, size_t len)
+{
+	syslog(LOG_ERR, "%.*s", (int)len, data);
+	return  len;
+}
+
+#define BESS_ID "bessd"
+static void setup_syslog()
+{
+	cookie_io_functions_t stdout_funcs = {
+		.write = &stdout_writer,
+		.read = NULL,
+		.close = NULL, 
+		.seek = NULL
+	};
+
+	cookie_io_functions_t stderr_funcs = {
+		.write = &stderr_writer,
+		.read = NULL,
+		.close = NULL, 
+		.seek = NULL
+	};
+
+	openlog(BESS_ID, LOG_CONS | LOG_NDELAY, LOG_DAEMON);
+
+	setvbuf(stderr = fopencookie(NULL, "w", stderr_funcs), NULL, _IOLBF, 0);
+
+	setvbuf(stdout = fopencookie(NULL, "w", stdout_funcs), NULL, _IOLBF, 0);
+}
+
+static void end_syslog()
+{
+	closelog();
+}
+#endif