Replace daemon() function with fork()

daemon() is a BSD-ism. Although it is available on many platforms
it is not a standard function. Some platforms (e.g. MacOSX) deprecated
it.

It is safer just to use fork() function that is a part of POSIX.

3 files changed, 48 insertions, 7 deletions

diff --git a/ChangeLog b/ChangeLog
index 655bee8..eedab2f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2011-09-23  Miklos Szeredi <miklos@szeredi.hu>
+
+	* Replace daemon() function with fork().  Patch by Anatol Pomozov
+
 2011-08-26  Miklos Szeredi <miklos@szeredi.hu>
 
 	* If configured with --disable-mtab then don't call mount(8) from
diff --git a/lib/helper.c b/lib/helper.c
index 0ba6d4f..ace19dd 100644
--- a/lib/helper.c
+++ b/lib/helper.c
@@ -179,14 +179,38 @@ err:
 
 int fuse_daemonize(int foreground)
 {
-	int res;
-
 	if (!foreground) {
-		res = daemon(0, 0);
-		if (res == -1) {
-			perror("fuse: failed to daemonize program\n");
+		int nullfd;
+
+		/*
+		 * demonize current process by forking it and killing the
+		 * parent.  This makes current process as a child of 'init'.
+		 */
+		switch(fork()) {
+		case -1:
+			perror("fuse_daemonize: fork");
+			return -1;
+		case 0:
+			break;
+		default:
+			_exit(0);
+		}
+
+		if (setsid() == -1) {
+			perror("fuse_daemonize: setsid");
 			return -1;
 		}
+
+		(void) chdir("/");
+
+		nullfd = open("/dev/null", O_RDWR, 0);
+		if (nullfd != -1) {
+			(void) dup2(nullfd, 0);
+			(void) dup2(nullfd, 1);
+			(void) dup2(nullfd, 2);
+			if (nullfd > 2)
+				close(nullfd);
+		}
 	}
 	return 0;
 }
diff --git a/util/ulockmgr_server.c b/util/ulockmgr_server.c
index 583fcf9..baef45d 100644
--- a/util/ulockmgr_server.c
+++ b/util/ulockmgr_server.c
@@ -352,11 +352,24 @@ int main(int argc, char *argv[])
 	if (*end)
 		goto out_inval;
 
-	if (daemon(0, 1) == -1) {
-		perror("ulockmgr_server: daemon");
+	/* demonize current process */
+	switch(fork()) {
+	case -1:
+		perror("ulockmgr_server: fork");
 		exit(1);
+	case 0:
+		break;
+	default:
+		_exit(0);
 	}
 
+	if (setsid() == -1) {
+		perror("ulockmgr_server: setsid");
+		exit(1);
+	}
+
+	(void) chdir("/");
+
 	sigemptyset(&empty);
 	sigprocmask(SIG_SETMASK, &empty, NULL);