From 4addcbbd510bb003ad2cd2c3e034252cb73b7dee Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Wed, 8 Feb 2023 22:16:39 +0000
Subject: [PATCH] turn run-qemu.sh script into mips-vm buildEnv command

---
 README.md                                     | 30 ++++++++++---------
 default.nix                                   |  1 +
 overlay.nix                                   |  1 +
 pkgs/mips-vm/default.nix                      | 11 +++++++
 .../run-qemu.sh => pkgs/mips-vm/mips-vm.sh    | 25 ++++++++++++----
 tests/pppoe/getaddress.expect                 |  2 +-
 tests/pppoe/test.nix                          | 15 ++++------
 7 files changed, 54 insertions(+), 31 deletions(-)
 create mode 100644 pkgs/mips-vm/default.nix
 rename scripts/run-qemu.sh => pkgs/mips-vm/mips-vm.sh (56%)

diff --git a/README.md b/README.md
index 2c6fb4a..1d06f26 100644
--- a/README.md
+++ b/README.md
@@ -93,23 +93,25 @@ in the right way
 
 ### Running Liminix in Qemu
 
-`./scripts/run-qemu.sh` accepts a kernel vmlinux image and a squashfs
-and runs qemu with appropriate config for two ethernet interfaces
-hooked up to "lan" and "access" respectively. It connects the Liminix serial console
-and the [QEMU monitor](https://www.qemu.org/docs/master/system/monitor.html) to
-stdin/stdout. Use ^P (not ^A) to switch to the monitor.
+In a `buildEnv` nix-shell, you can use the `mips-vm` command
+to run Qemu with appropriate config for two ethernet interfaces
+hooked up to "lan" and "access" respectively. It connects the Liminix
+serial console and the [QEMU monitor](https://www.qemu.org/docs/master/system/monitor.html) to stdin/stdout. Use ^P (not ^A) to switch to the monitor.
 
-If you run with `--background /path/to/unix/socket` it will fork into
-the background and open a Unix socket at that pathname to communicate
-on. Use `./scripts/connect-qemu.sh` to connect to it, and ^O to
-disconnect.
+    nix-shell -A buildEnv --arg device '(import ./devices/qemu)' --run "mips-vm result/vmlinux result/squashfs"
+
+If you run with `--background /path/to/some/directory` as the first
+parameter, it will fork into the background and open Unix sockets in
+that directory for console and monitor.  Use
+`./scripts/connect-qemu.sh` to connect to either of these sockets, and
+^O to disconnect.
 
 ### Emulated upstream connection
 
-In the tests/support/ppp-server directory there is a derivation
-to install and configure [Mikrotik RouterOS](https://mikrotik.com/software) as
-a PPPoE access concentrator connected to the `access` and `world`
-networks, so that Liminix PPPoE client support can be tested.
+In pkgs/routeros there is a derivation to install and configure
+[Mikrotik RouterOS](https://mikrotik.com/software) as a PPPoE access
+concentrator connected to the `access` and `world` networks, so that
+Liminix PPPoE client support can be tested.
 
 This is made available in the `buildEnv`, so you can do something like
 
@@ -132,8 +134,8 @@ you can run all of the tests by evaluating `ci.nix`:
 
     nix-build --argstr liminix `pwd`  --argstr nixpkgs `pwd`/../nixpkgs  --argstr unstable `pwd`/../unstable-nixpkgs/ ci.nix
 
+or to run a named test, use the `-A` flag. For example, `-A pppoe`
 
-Some of the tests require the emulated upstream connection to be running.
 
 ## Hardware
 
diff --git a/default.nix b/default.nix
index 4a3b6c0..6ec720f 100644
--- a/default.nix
+++ b/default.nix
@@ -102,6 +102,7 @@ in {
       tufted
       routeros.routeros
       routeros.ros-exec-script
+      mips-vm
     ];
   };
 }
diff --git a/overlay.nix b/overlay.nix
index e00aac4..0d046b3 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -25,6 +25,7 @@ final: prev: {
     nettle = null;
   };
 
+  mips-vm = final.callPackage ./pkgs/mips-vm {};
   pppoe = final.callPackage ./pkgs/pppoe {};
   ppp =
     (prev.ppp.override {
diff --git a/pkgs/mips-vm/default.nix b/pkgs/mips-vm/default.nix
new file mode 100644
index 0000000..7c1b22e
--- /dev/null
+++ b/pkgs/mips-vm/default.nix
@@ -0,0 +1,11 @@
+{
+  qemu
+, writeShellScriptBin
+, stdenv
+, lib
+}:
+writeShellScriptBin "mips-vm"
+  ''
+     export PATH="${lib.makeBinPath [qemu]}:$PATH"
+     ${builtins.readFile ./mips-vm.sh}
+  ''
diff --git a/scripts/run-qemu.sh b/pkgs/mips-vm/mips-vm.sh
similarity index 56%
rename from scripts/run-qemu.sh
rename to pkgs/mips-vm/mips-vm.sh
index 24e3b8f..9409981 100755
--- a/scripts/run-qemu.sh
+++ b/pkgs/mips-vm/mips-vm.sh
@@ -1,16 +1,29 @@
-#!/usr/bin/env nix-shell
-#! nix-shell -i bash -p qemu
+#!/usr/bin/env bash
+
+usage(){
+    echo "usage: $(basename $0) [--background /path/to/state_directory] kernel rootimg"
+    echo -e "\nWithout --background, use C-p c (not C-a c) to switch to the monitor"
+    exit 1
+}
 
 if test "$1" = "--background" ; then
-    socket=$2
-    pid="`dirname $socket`/`basename $socket .sock`.pid"
+    statedir=$2
+    if test -z "$statedir" || ! test -d $statedir ; then
+	usage
+    fi
+    pid="${statedir}/pid"
+    socket="${statedir}/console"
+    monitor="${statedir}/monitor"
     echo "running in background, socket is $socket, pid $pid"
-    flags="--daemonize --pidfile $pid -chardev socket,id=sock,path=$2,server=on,wait=off,mux=on -mon chardev=sock,mode=readline -serial chardev:sock  "
+    flags="--daemonize --pidfile $pid -serial unix:$socket,server,nowait -monitor unix:$monitor,server,nowait"
     shift;shift
 else
     flags="-serial mon:stdio"
 fi
 
+test -n "$2" || usage
+
+
 INIT=${INIT-/bin/init}
 echo $QEMU_OPTIONS
 qemu-system-mips \
@@ -22,4 +35,4 @@ qemu-system-mips \
     -device virtio-net-pci,disable-legacy=on,disable-modern=off,netdev=access,mac=ba:ad:1d:ea:21:02 \
     -netdev socket,id=lan,mcast=230.0.0.1:1235,localaddr=127.0.0.1 \
     -device virtio-net-pci,disable-legacy=on,disable-modern=off,netdev=lan,mac=ba:ad:1d:ea:21:01 \
-    -kernel $1 -display none $flags     ${QEMU_OPTIONS}
+    -kernel $1 -display none $flags ${QEMU_OPTIONS}
diff --git a/tests/pppoe/getaddress.expect b/tests/pppoe/getaddress.expect
index bb88202..ea283e9 100644
--- a/tests/pppoe/getaddress.expect
+++ b/tests/pppoe/getaddress.expect
@@ -1,6 +1,6 @@
 set timeout 60
 
-spawn socat unix-connect:foo.sock -
+spawn socat unix-connect:vm/console -
 send "\r\n"
 expect "login:" {  send "root\r\n" }
 expect "/ #"
diff --git a/tests/pppoe/test.nix b/tests/pppoe/test.nix
index 258bb47..f5ef219 100644
--- a/tests/pppoe/test.nix
+++ b/tests/pppoe/test.nix
@@ -7,20 +7,15 @@ let img = (import liminix {
       liminix-config = ./configuration.nix;
     }).outputs.default;
     pkgs = import <nixpkgs> { overlays = [(import ../../overlay.nix)]; };
-    ros = pkgs.pkgsBuildBuild.routeros;
-    run-qemu = pkgs.writeShellScriptBin "run-qemu" ''
-      export PATH="${pkgs.lib.makeBinPath [pkgs.qemu]}:$PATH"
-      ${builtins.readFile ../../scripts/run-qemu.sh}
-    '';
-
+    inherit (pkgs.pkgsBuildBuild) routeros mips-vm;
 in pkgs.runCommand "check" {
   nativeBuildInputs = with pkgs; [
     python3Packages.scapy
     expect
     jq
     socat
-    ros.routeros
-    run-qemu
+    routeros.routeros
+    mips-vm
   ] ;
 } ''
 serverstatedir=$(mktemp -d -t routeros-XXXXXX)
@@ -50,8 +45,8 @@ fatal(){
 trap fatal ERR
 
 routeros $serverstatedir
-
-run-qemu --background foo.sock ${img}/vmlinux ${img}/squashfs
+mkdir vm
+mips-vm --background ./vm ${img}/vmlinux ${img}/squashfs
 expect ${./getaddress.expect}
 
 set -o pipefail