Add revoke(1).

While hacking on TTY code, I often miss a small utility to revoke my own
(pseudo-)terminals. This small utility is just a small wrapper around
the revoke(2) call, so you can destroy your very own login sessions.

Approved by:	re

lib/libc/sys/revoke.2

@@ -97,7 +97,8 @@ operation on the named file.
 The caller is neither the owner of the file nor the super user.
 .El
 .Sh SEE ALSO
-.Xr close 2
+.Xr close 2 ,
+.Xr revoke 1
 .Sh HISTORY
 The
 .Fn revoke

usr.bin/Makefile

@@ -157,6 +157,7 @@ SUBDIR=	alias \
 	${_quota} \
 	renice \
 	rev \
+	revoke \
 	${_rlogin} \
 	${_rpcgen} \
 	rpcinfo \

usr.bin/revoke/Makefile

@@ -0,0 +1,7 @@
+# $FreeBSD$
+
+PROG=	revoke
+
+WARNS?=	6
+
+.include <bsd.prog.mk>

usr.bin/revoke/revoke.1

@@ -0,0 +1,56 @@
+.\" Copyright (c) 2009 Ed Schouten <ed@FreeBSD.org>
+.\" All rights reserved.
+.\" 
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\" 
+.\" $FreeBSD$
+.\"
+.Dd June 15, 2009
+.Dt REVOKE 1
+.Os
+.Sh NAME
+.Nm revoke
+.Nd "revoke a character device"
+.Sh SYNOPSIS
+.Nm
+.Ar
+.Sh DESCRIPTION
+The
+.Nm
+program revokes the character devices using
+.Xr revoke 2 .
+When used on a TTY, calls like
+.Xr read 2 ,
+.Xr write 2
+and
+.Xr ioctl 2 ,
+will be aborted immediately, effectively causing login sessions to be
+terminated.
+.Sh SEE ALSO
+.Xr revoke 2
+.Sh HISTORY
+The
+.Nm
+program first appeared in
+.Fx 8.0 .
+.Sh AUTHORS
+.An Ed Schouten Aq ed@FreeBSD.org

usr.bin/revoke/revoke.c

@@ -0,0 +1,59 @@
+/*-
+ * Copyright (c) 2009 Ed Schouten <ed@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static void
+usage(void)
+{
+
+	fprintf(stderr, "usage: revoke file ...\n");
+	exit(1);
+}
+
+int
+main(int argc, char *argv[])
+{
+	char **d;
+	int error = 0;
+
+	if (argc == 1)
+		usage();
+
+	for (d = &argv[1]; *d != NULL; d++) {
+		if (revoke(*d) != 0) {
+			perror(*d);
+			error = 1;
+		}
+	}
+
+	return (error);
+}