[src/trunk]: src/sys As discussed on tech-kern: define a new tty internal sta...

[martin <martin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0940d8dcb95c
branches:  trunk
changeset: 357205:0940d8dcb95c
user:      martin <martin%NetBSD.org@localhost>
date:      Tue Oct 31 10:45:19 2017 +0000

description:
As discussed on tech-kern: define a new tty internal state flag: TS_KERN_ONLY

Implement it in a few tty drivers. If this flag is set, the underlying
hardware is used by another driver and userland has no right to open
it. A few uses will appear soon in sys/dev/sun/sun{kbd,ms}.c.

diffstat:

 sys/arch/sparc64/dev/sab.c |  11 +++++++++--
 sys/dev/ic/com.c           |  17 +++++++++++++++--
 sys/dev/ic/z8530tty.c      |  11 +++++++++--
 sys/sys/tty.h              |   6 +++++-
 4 files changed, 38 insertions(+), 7 deletions(-)

diffs (129 lines):

diff -r f59225cfaabc -r 0940d8dcb95c sys/arch/sparc64/dev/sab.c
--- a/sys/arch/sparc64/dev/sab.c        Tue Oct 31 10:39:13 2017 +0000
+++ b/sys/arch/sparc64/dev/sab.c        Tue Oct 31 10:45:19 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sab.c,v 1.54 2014/11/15 19:20:02 christos Exp $        */
+/*     $NetBSD: sab.c,v 1.55 2017/10/31 10:45:19 martin Exp $  */
 /*     $OpenBSD: sab.c,v 1.7 2002/04/08 17:49:42 jason Exp $   */
 
 /*
@@ -42,7 +42,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sab.c,v 1.54 2014/11/15 19:20:02 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sab.c,v 1.55 2017/10/31 10:45:19 martin Exp $");
 
 #include "opt_kgdb.h"
 #include <sys/types.h>
@@ -681,6 +681,13 @@
        tp = sc->sc_tty;
        tp->t_dev = dev;
 
+       /*
+        * If the device is exclusively for kernel use, deny userland
+        * open.
+        */
+       if (ISSET(tp->t_state, TS_KERN_ONLY))
+               return (EBUSY);
+
        if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
                return (EBUSY);
 
diff -r f59225cfaabc -r 0940d8dcb95c sys/dev/ic/com.c
--- a/sys/dev/ic/com.c  Tue Oct 31 10:39:13 2017 +0000
+++ b/sys/dev/ic/com.c  Tue Oct 31 10:45:19 2017 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: com.c,v 1.344 2017/10/29 14:06:08 jmcneill Exp $ */
+/* $NetBSD: com.c,v 1.345 2017/10/31 10:45:19 martin Exp $ */
 
 /*-
  * Copyright (c) 1998, 1999, 2004, 2008 The NetBSD Foundation, Inc.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: com.c,v 1.344 2017/10/29 14:06:08 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: com.c,v 1.345 2017/10/31 10:45:19 martin Exp $");
 
 #include "opt_com.h"
 #include "opt_ddb.h"
@@ -879,6 +879,13 @@
 
        tp = sc->sc_tty;
 
+       /*
+        * If the device is exclusively for kernel use, deny userland
+        * open.
+        */
+       if (ISSET(tp->t_state, TS_KERN_ONLY))
+               return (EBUSY);
+
        if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
                return (EBUSY);
 
@@ -1017,6 +1024,12 @@
        /* XXX This is for cons.c. */
        if (!ISSET(tp->t_state, TS_ISOPEN))
                return (0);
+       /*
+        * If the device is exclusively for kernel use, deny userland
+        * close.
+        */
+       if (ISSET(tp->t_state, TS_KERN_ONLY))
+               return (0);
 
        (*tp->t_linesw->l_close)(tp, flag);
        ttyclose(tp);
diff -r f59225cfaabc -r 0940d8dcb95c sys/dev/ic/z8530tty.c
--- a/sys/dev/ic/z8530tty.c     Tue Oct 31 10:39:13 2017 +0000
+++ b/sys/dev/ic/z8530tty.c     Tue Oct 31 10:45:19 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: z8530tty.c,v 1.131 2014/11/15 19:18:18 christos Exp $  */
+/*     $NetBSD: z8530tty.c,v 1.132 2017/10/31 10:45:19 martin Exp $    */
 
 /*-
  * Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998, 1999
@@ -137,7 +137,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: z8530tty.c,v 1.131 2014/11/15 19:18:18 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: z8530tty.c,v 1.132 2017/10/31 10:45:19 martin Exp $");
 
 #include "opt_kgdb.h"
 #include "opt_ntp.h"
@@ -560,6 +560,13 @@
        if (tp == NULL)
                return (EBUSY);
 
+       /*
+        * If the device is exclusively for kernel use, deny userland
+        * open.
+        */
+       if (ISSET(tp->t_state, TS_KERN_ONLY))
+               return (EBUSY);
+
        if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
                return (EBUSY);
 
diff -r f59225cfaabc -r 0940d8dcb95c sys/sys/tty.h
--- a/sys/sys/tty.h     Tue Oct 31 10:39:13 2017 +0000
+++ b/sys/sys/tty.h     Tue Oct 31 10:45:19 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tty.h,v 1.93 2014/11/15 19:17:05 christos Exp $        */
+/*     $NetBSD: tty.h,v 1.94 2017/10/31 10:45:19 martin Exp $  */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -203,6 +203,10 @@
 #define        TS_TYPEN        0x08000         /* Retyping suspended input (PENDIN). */
 #define        TS_LOCAL        (TS_BKSL | TS_CNTTB | TS_ERASE | TS_LNCH | TS_TYPEN)
 
+/* for special line disciplines, like dev/sun/sunkbd.c */
+#define        TS_KERN_ONLY    0x10000         /* Device is accessible by kernel
+                                        * only, deny all userland access */
+
 /* Character type information. */
 #define        ORDINARY        0
 #define        CONTROL         1