lib/: Set O_CLOEXEC for static FILE handles

With glibc we can use "e" in mode argument to set O_CLOEXEC on
opened files. The /etc/shadow and /etc/gshadow file handles should
be protected to make sure that they are never passed to child
processes by accident.

Reviewed-by: Alejandro Colomar <alx@kernel.org>
Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>

lib/gshadow.c

@@ -55,7 +55,7 @@ void setsgent (void)
 	if (NULL != shadow) {
 		rewind (shadow);
 	} else {
-		shadow = fopen (SGROUP_FILE, "r");
+		shadow = fopen (SGROUP_FILE, "re");
 	}
 }
 

lib/shadow.c

@@ -41,7 +41,7 @@ void setspent (void)
 	if (NULL != shadow) {
 		rewind (shadow);
 	}else {
-		shadow = fopen (SHADOW_FILE, "r");
+		shadow = fopen (SHADOW_FILE, "re");
 	}
 }