arpd/ifstat/nstat/rtacct: use daemon()

A bunch of misc utils basically reimplement the daemon() function (the
whole fork/close/chdir/etc...).  Rather than do that, use daemon() as
that will work under nommu Linux systems that lack fork().
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

misc/arpd.c

@@ -775,27 +775,9 @@ int main(int argc, char **argv)
 
 	load_initial_table();
 
-	if (1) {
-		int fd;
-		pid_t pid = fork();
-
-		if (pid > 0)
-			_exit(0);
-		if (pid < 0) {
-			perror("arpd: fork");
-			goto do_abort;
-		}
-
-		chdir("/");
-		fd = open("/dev/null", O_RDWR);
-		if (fd >= 0) {
-			dup2(fd, 0);
-			dup2(fd, 1);
-			dup2(fd, 2);
-			if (fd > 2)
-				close(fd);
-		}
-		setsid();
+	if (daemon(0, 0)) {
+		perror("arpd: daemon");
+		goto do_abort;
 	}
 
 	openlog("arpd", LOG_PID | LOG_CONS, LOG_DAEMON);

misc/ifstat.c

@@ -663,10 +663,10 @@ int main(int argc, char *argv[])
 			perror("ifstat: listen");
 			exit(-1);
 		}
-		if (fork())
-			exit(0);
-		chdir("/");
-		close(0); close(1); close(2); setsid();
+		if (daemon(0, 0)) {
+			perror("ifstat: daemon");
+			exit(-1);
+		}
 		signal(SIGPIPE, SIG_IGN);
 		signal(SIGCHLD, sigchild);
 		server_loop(fd);

misc/nstat.c

@@ -513,10 +513,10 @@ int main(int argc, char *argv[])
 			perror("nstat: listen");
 			exit(-1);
 		}
-		if (fork())
-			exit(0);
-		chdir("/");
-		close(0); close(1); close(2); setsid();
+		if (daemon(0, 0)) {
+			perror("nstat: daemon");
+			exit(-1);
+		}
 		signal(SIGPIPE, SIG_IGN);
 		signal(SIGCHLD, sigchild);
 		server_loop(fd);

misc/rtacct.c

@@ -524,10 +524,10 @@ int main(int argc, char *argv[])
 			perror("rtacct: listen");
 			exit(-1);
 		}
-		if (fork())
-			exit(0);
-		chdir("/");
-		close(0); close(1); close(2); setsid();
+		if (daemon(0, 0)) {
+			perror("rtacct: daemon");
+			exit(-1);
+		}
 		signal(SIGPIPE, SIG_IGN);
 		signal(SIGCHLD, sigchild);
 		server_loop(fd);