From 6ca93675ed11b7eb2615a4e5d005bfc18496d32a Mon Sep 17 00:00:00 2001
From: aiju <devnull@localhost>
Date: Fri, 15 Apr 2011 21:47:11 +0200
Subject: [PATCH] added /dev/mordor

---
 sys/man/3/arch         |  5 +++++
 sys/src/9/pc/devarch.c | 15 +++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/sys/man/3/arch b/sys/man/3/arch
index 7cd5e82fb..77ef0276f 100644
--- a/sys/man/3/arch
+++ b/sys/man/3/arch
@@ -12,6 +12,7 @@ arch \- architecture-specific information and control
 .B /dev/iol
 .B /dev/iow
 .B /dev/irqalloc
+.B /dev/mordor
 .SH DESCRIPTION
 This device presents textual information about PC hardware and allows
 user-level control of the I/O ports on x86-class and DEC Alpha machines.
@@ -121,6 +122,10 @@ cause 8-bit wide, 16-bit wide, and 32-bit wide requests to
 I/O ports.
 The port accessed is determined by the byte offset of the
 file descriptor.
+.PP
+Reads and writes to
+.IR mordor
+will inevitably cause the front to fall off.
 .SH EXAMPLE
 The following code reads from an x86 byte I/O port.
 .IP
diff --git a/sys/src/9/pc/devarch.c b/sys/src/9/pc/devarch.c
index 3228736ee..c45271682 100644
--- a/sys/src/9/pc/devarch.c
+++ b/sys/src/9/pc/devarch.c
@@ -987,6 +987,20 @@ archctlwrite(Chan*, void *a, long n, vlong)
 	return n;
 }
 
+static long
+mordorread(Chan*, void*, long, vlong)
+{
+	error("one does not simply read from mordor");
+	return 0;
+}
+
+static long
+mordorwrite(Chan*, void*, long, vlong)
+{
+	error("one does not simply write into mordor");
+	return 0;
+}
+
 void
 archinit(void)
 {
@@ -1035,6 +1049,7 @@ archinit(void)
 
 	addarchfile("cputype", 0444, cputyperead, nil);
 	addarchfile("archctl", 0664, archctlread, archctlwrite);
+	addarchfile("mordor", 0666, mordorread, mordorwrite);
 }
 
 /*