From 89a1609edd48f08e4227baa2890b96a936cfadb8 Mon Sep 17 00:00:00 2001 From: "Owen W. Taylor" Date: Tue, 18 Aug 2015 15:19:05 -0400 Subject: [PATCH 32/47] logind: get a fresh file descriptor to clean up a VT When the controlling process exits, any existing file descriptors for that FD will be marked as hung-up and ioctls on them will file with EIO. To work around this, open a new file descriptor for the VT we want to clean up. Thanks to Ray Strode for help in sorting out the problem and coming up with a fix! https://github.com/systemd/systemd/issues/989 --- src/login/logind-session.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/src/login/logind-session.c b/src/login/logind-session.c index a8e667b..9abdf62 100644 --- a/src/login/logind-session.c +++ b/src/login/logind-session.c @@ -1039,7 +1039,18 @@ void session_restore_vt(Session *s) { int vt, kb = K_XLATE; struct vt_mode mode = { 0 }; + /* We need to get a fresh handle to the virtual terminal, + * since the old file-descriptor is potentially in a hung-up + * state after the controlling process exited; we do a + * little dance to avoid having the terminal be available + * for reuse before we've cleaned it up. + */ + int old_fd = s->vtfd; + s->vtfd = -1; + vt = session_open_vt(s); + safe_close(old_fd); + if (vt < 0) return; -- 2.5.0