open /dev/null before chroot

5 files changed, 68 insertions, 34 deletions

diff --git a/usr.sbin/bind/bin/named/main.c b/usr.sbin/bind/bin/named/main.c
index c2c93ebd484..4d318f6db17 100644
--- a/usr.sbin/bind/bin/named/main.c
+++ b/usr.sbin/bind/bin/named/main.c
@@ -461,9 +461,10 @@ setup(void) {
 	ns_os_inituserinfo(ns_g_username);
 
 	/*
-	 * Initialize time conversion information
+	 * Initialize time conversion information and /dev/null
 	 */
 	ns_os_tzset();
+	ns_os_opendevnull();
 
 	ns_os_chroot(ns_g_chrootdir);
 
diff --git a/usr.sbin/bind/bin/named/unix/include/named/os.h b/usr.sbin/bind/bin/named/unix/include/named/os.h
index 6f4e8d80043..acf6e2094fb 100644
--- a/usr.sbin/bind/bin/named/unix/include/named/os.h
+++ b/usr.sbin/bind/bin/named/unix/include/named/os.h
@@ -29,6 +29,12 @@ void
 ns_os_daemonize(void);
 
 void
+ns_os_opendevnull(void);
+
+void
+ns_os_closedevnull(void);
+
+void
 ns_os_chroot(const char *root);
 
 void
diff --git a/usr.sbin/bind/bin/named/unix/os.c b/usr.sbin/bind/bin/named/unix/os.c
index 0affc4ca39a..a6dfa76633d 100644
--- a/usr.sbin/bind/bin/named/unix/os.c
+++ b/usr.sbin/bind/bin/named/unix/os.c
@@ -43,6 +43,7 @@
 #include <named/os.h>
 
 static char *pidfile = NULL;
+static int devnullfd = -1;
 
 /*
  * If there's no <linux/capability.h>, we don't care about <sys/prctl.h>
@@ -288,7 +289,6 @@ ns_os_init(const char *progname) {
 void
 ns_os_daemonize(void) {
 	pid_t pid;
-	int fd;
 	char strbuf[ISC_STRERRORSIZE];
 
 	pid = fork();
@@ -322,21 +322,35 @@ ns_os_daemonize(void) {
 	 * and will end up closing the wrong FD.  This will be fixed eventually,
 	 * and these calls will be removed.
 	 */
-	fd = open("/dev/null", O_RDWR, 0);
-	if (fd != -1) {
-		close(STDIN_FILENO);
-		(void)dup2(fd, STDIN_FILENO);
-		close(STDOUT_FILENO);
-		(void)dup2(fd, STDOUT_FILENO);
-		close(STDERR_FILENO);
-		(void)dup2(fd, STDERR_FILENO);
-		if (fd != STDIN_FILENO &&
-		    fd != STDOUT_FILENO &&
-		    fd != STDERR_FILENO)
-			(void)close(fd);
+	if (devnullfd != -1) {
+		if (devnullfd != STDIN_FILENO) {
+			(void)close(STDIN_FILENO);
+			(void)dup2(devnullfd, STDIN_FILENO);
+		}
+		if (devnullfd != STDOUT_FILENO) {
+			(void)close(STDOUT_FILENO);
+			(void)dup2(devnullfd, STDOUT_FILENO);
+		}
+		if (devnullfd != STDERR_FILENO) {
+			(void)close(STDERR_FILENO);
+			(void)dup2(devnullfd, STDERR_FILENO);
+		}
 	}
 }
 
+void
+ns_os_opendevnull(void) {
+	devnullfd = open("/dev/null", O_RDWR, 0);
+}
+
+void
+ns_os_closedevnull(void) {
+	if (devnullfd != STDIN_FILENO &&
+	    devnullfd != STDOUT_FILENO &&
+	    devnullfd != STDERR_FILENO)
+		close(devnullfd);
+}
+
 static isc_boolean_t
 all_digits(const char *s) {
 	if (*s == '\0')
diff --git a/usr.sbin/bind/bin/named/win32/include/named/os.h b/usr.sbin/bind/bin/named/win32/include/named/os.h
index b0387f2d9d5..02f9a5bd150 100644
--- a/usr.sbin/bind/bin/named/win32/include/named/os.h
+++ b/usr.sbin/bind/bin/named/win32/include/named/os.h
@@ -29,6 +29,12 @@ void
 ns_os_daemonize(void);
 
 void
+ns_os_opendevnull(void);
+
+void
+ns_os_closedevnull(void);
+
+void
 ns_os_chroot(const char *root);
 
 void
diff --git a/usr.sbin/bind/bin/named/win32/os.c b/usr.sbin/bind/bin/named/win32/os.c
index c574daaf433..bcb0cfe37c3 100644
--- a/usr.sbin/bind/bin/named/win32/os.c
+++ b/usr.sbin/bind/bin/named/win32/os.c
@@ -44,6 +44,7 @@
 
 
 static char *pidfile = NULL;
+static int devnullfd = -1;
 
 static BOOL Initialized = FALSE;
 
@@ -85,34 +86,40 @@ ns_os_init(const char *progname) {
 
 void
 ns_os_daemonize(void) {
-	int fd;
-
 	/*
 	 * Try to set stdin, stdout, and stderr to /dev/null, but press
 	 * on even if it fails.
-	 *
-	 * XXXMLG The close() calls here are unneeded on all but NetBSD, but
-	 * are harmless to include everywhere.  dup2() is supposed to close
-	 * the FD if it is in use, but unproven-pthreads-0.16 is broken
-	 * and will end up closing the wrong FD.  This will be fixed eventually,
-	 * and these calls will be removed.
 	 */
-	fd = open("NUL", O_RDWR, 0);
-	if (fd != -1) {
-		close(_fileno(stdin));
-		(void)_dup2(fd, _fileno(stdin));
-		close(_fileno(stdout));
-		(void)_dup2(fd, _fileno(stdout));
-		close(_fileno(stderr));
-		(void)_dup2(fd, _fileno(stderr));
-		if (fd != _fileno(stdin) &&
-		    fd != _fileno(stdout) &&
-		    fd != _fileno(stderr))
-			(void)close(fd);
+	if (devnullfd != -1) {
+		if (devnullfd != _fileno(stdin)) {
+			close(_fileno(stdin));
+			(void)_dup2(devnullfd, _fileno(stdin));
+		}
+		if (devnullfd != _fileno(stdout)) {
+			close(_fileno(stdout));
+			(void)_dup2(devnullfd, _fileno(stdout));
+		}
+		if (devnullfd != _fileno(stderr)) {
+			close(_fileno(stderr));
+			(void)_dup2(devnullfd, _fileno(stderr));
+		}
 	}
 }
 
 void
+ns_os_opendevnull(void) {
+	devnullfd = open("NUL", O_RDWR, 0);
+}
+
+void
+ns_os_closedevnull(void) {
+	if (devnullfd != _fileno(stdin) &&
+	    devnullfd != _fileno(stdout) &&
+	    devnullfd != _fileno(stderr))
+		close(devnullfd);
+}
+
+void
 ns_os_chroot(const char *root) {
 }