svn commit: r315733 - in head: include lib/libc/gen libexec/getty

[Warner Losh]

Author: imp
Date: Wed Mar 22 19:00:41 2017
New Revision: 315733
URL: https://svnweb.freebsd.org/changeset/base/315733

Log:
  Impelemnt ttys onifexists in init.
  
  Implement a new init(8) option in /etc/ttys. If this option is present
  on the entry in /etc/ttys, the entry will be active if and only if it
  exists.  If the name starts with a '/', it will be considered an
  absolute path. If not, it will be a path relative to /dev.
  
  This allows one to turn off video console getty that aren't present
  (while running a getty on them even when they aren't the system
  console). Likewise with serial ports.
  
  It differs from onifconsole in only requiring the device exist rather
  than it be listed as one of the system consoles.
  
  Sponsored by: Netflix
  Differential Revision: https://reviews.freebsd.org/D10037

Modified:
  head/include/ttyent.h
  head/lib/libc/gen/getttyent.c
  head/libexec/getty/ttys.5

Modified: head/include/ttyent.h
==============================================================================
--- head/include/ttyent.h	Wed Mar 22 18:45:13 2017	(r315732)
+++ head/include/ttyent.h	Wed Mar 22 19:00:41 2017	(r315733)
@@ -38,6 +38,7 @@
 #define	_TTYS_OFF	"off"
 #define	_TTYS_ON	"on"
 #define	_TTYS_ONIFCONSOLE "onifconsole"
+#define	_TTYS_ONIFEXISTS "onifexists"
 #define	_TTYS_SECURE	"secure"
 #define	_TTYS_INSECURE	"insecure"
 #define	_TTYS_WINDOW	"window"

Modified: head/lib/libc/gen/getttyent.c
==============================================================================
--- head/lib/libc/gen/getttyent.c	Wed Mar 22 18:45:13 2017	(r315732)
+++ head/lib/libc/gen/getttyent.c	Wed Mar 22 19:00:41 2017	(r315733)
@@ -97,6 +97,26 @@ done:
 	return (0);
 }
 
+static int
+auto_exists_status(const char *ty_name)
+{
+	struct stat sb;
+	char *dev;
+	int rv;
+
+	rv = 0;
+	if (*ty_name == '/')
+		asprintf(&dev, "%s", ty_name);
+	else
+		asprintf(&dev, "/dev/%s", ty_name);
+	if (dev == NULL)
+		return 0;
+	if (stat(dev, &sb) == 0)
+		rv = TTY_ON;
+	free(dev);
+	return (rv);
+}
+
 struct ttyent *
 getttyent(void)
 {
@@ -161,6 +181,8 @@ getttyent(void)
 			tty.ty_status |= TTY_ON;
 		else if (scmp(_TTYS_ONIFCONSOLE))
 			tty.ty_status |= auto_tty_status(tty.ty_name);
+		else if (scmp(_TTYS_ONIFEXISTS))
+			tty.ty_status |= auto_exists_status(tty.ty_name);
 		else if (scmp(_TTYS_SECURE))
 			tty.ty_status |= TTY_SECURE;
 		else if (scmp(_TTYS_INSECURE))

Modified: head/libexec/getty/ttys.5
==============================================================================
--- head/libexec/getty/ttys.5	Wed Mar 22 18:45:13 2017	(r315732)
+++ head/libexec/getty/ttys.5	Wed Mar 22 19:00:41 2017	(r315733)
@@ -28,7 +28,7 @@
 .\"     from: @(#)ttys.5	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\" "
-.Dd March 9, 2014
+.Dd March 16, 2017
 .Dt TTYS 5
 .Os
 .Sh NAME
@@ -105,6 +105,12 @@ should (should not) execute the command 
 ``onifconsole'' will cause this line to be enabled if and only if it is
 an active kernel console device (it is equivalent to ``on'' in this
 case).
+The flag ``onifexists'' will cause this line to be enabled if and only
+if the name exists.
+If the name starts with a ``/'', it will be considered an absolute
+path.
+Otherwise, it is considered a path relative to
+.Pa /dev .
 The flag ``secure'' (if the console is enabled) allows users with a
 uid of 0 to login on
 this line.