Modified Cygwin startxwin script that syncs X11 with WSL

cygwin xserver.md

Using cygwin X in WSL1 and MingW (and others)

Cygwin comes with an X Server that can be useful with tools other than Cygwin itself. With a few modifications, we can add cygwin's X Server support to other shell implementations including cygwin, mingw64 (such as git for windows), msys2, WSL1, WSL2, and others.

With a few minor modifications, we can save the DISPLAY variable to files accessible by any shell. Once the DISPLAY value is accessible, an rc file can load it and it will automatically be used.

Optionally, we can even add a "one click" link to the start menu to start the xserver

TL;DR

Open Command Prompt

mkdir C:\cygwin64
powershell -NoProfile -Command "Invoke-WebRequest -Uri "https://cygwin.com/setup-x86_64.exe" -OutFile "c:\cygwin64\setup-x86_64.exe"
cd \cygwin64
setup-x86_64.exe -l C:\cygwin64\packages -qnNd -P xorg-server -P xinit -P libiconv
.\bin\bash.exe -l

Now that you are in cygwin bash

cd /
curl -LO https://gist.githubusercontent.com/andyneff/712b2b02e1757f23526776a997856c29/raw/startx.bat
curl -LO https://gist.github.com/andyneff/712b2b02e1757f23526776a997856c29/raw/startxwin

And Add this to your WSL .bashrc

if [ -f ~/.displayrc ]; then
  source ~/.displayrc
  # This prevents an annoying Terminal hang every time an ssh client tried to access a dead X session
  if ! timeout 1 xhost &> /dev/null; then
    unset DISPLAY
    rm ~/.displayrc
  fi
fi

Finally run: C:\cygwin64\startx.bat

Getting started

1. Download cygwin installer and place it in C:\cygwin64\setup-x86_64.exe

2. Open up a command prompt to C:\cygwin64 and run: setup-x86_64.exe -l C:\cygwin64\packages -qnNd -P xorg-server -P xinit -P libiconv (all you need to do is click Next and Pick the mirrors. The required packages will already be selected)

3. Download these two files (startx.bat and startxwin and put them in C:\cywin64\. (If you put them somewhere else, you will need to update the first two %~dp0s in startx.bat to point to C:\cywin64\)

   • Recommended way:
   • Start Cygwin

   cd /
   curl -LO https://gist.githubusercontent.com/andyneff/712b2b02e1757f23526776a997856c29/raw/startx.bat
   curl -LO https://gist.github.com/andyneff/712b2b02e1757f23526776a997856c29/raw/startxwin
   

4. Edit your .bashrc (Your WSL bashrc, for example) to include the following (other other rc files if you don't use bash)

   if [ -f ~/.displayrc ]; then
     source ~/.displayrc
   fi

5. (Optional) There are other ways to do this, but here is one way to add a shortcut to your start menu

   • Create a shortcut to startx.bat (anywhere, your Desktop for example). Name it and give it the icon you want
   • Move the shortcut to one of the two locations:
     • C:\ProgramData\Microsoft\Windows\Start Menu (for all users, need admin access)
     • C:\%USERPROFILE%\AppData\Roaming\Microsoft\Windows\Start Menu (for just you)
   • Now the shortcut will show up on your Start Menu under Recently Added
     • Sometimes you need to type in the name to search for it. If you named the shortcut "StartX", type that in to find it
     • 
   • Right click the icon, and select "Pin to Start"

6. Run the startx.bat file for the first time. When prompted by Windows Firewall (or your firewall) Allow xwin.exe to communicate on the appropriate networks (Domain and Private, for example. Public networks is strongly discouraged, for privacy and security concerns)

7. Now you should see two in your system tray

FAQ

1. What about WSL2's X Server?
   • I suspect if the WSL2 server leave nothing lacking, this will all become obsolete. Lets hope that happens!
2. Does this work on WSL2?
   • It should...
   • localhost from WSL 2 does not work: microsoft/WSL#4619
   • IP for vEthernet (WSL) is used instead of localhost
     • If there are multiple Network adapters with WSL in the name, this could cause error.
3. What about WSL2 with VPN?
   • There are many things that can go wrong with WSL2 on VPN, and many of them will need to be solved manually. The most extreme would be to use VPN Kit to add internet to WSL2

startx.bat

@echo off
setlocal enableextensions
set TERM=
"%~dp0bin\cygstart" --hide "%~dp0bin\bash" --login "%~dp0startxwin"

startxwin

#!/bin/sh

# This is just a sample implementation of a slightly less primitive
# interface than xinit. It looks for user .xinitrc and .xserverrc
# files, then system xinitrc and xserverrc files, else lets xinit choose
# its default. The system xinitrc should probably do things like check
# for .Xresources files and merge them in, start up a window manager,
# and pop a clock and several xterms.
#
# Site administrators are STRONGLY urged to write nicer versions.
#

unset DBUS_SESSION_BUS_ADDRESS
unset SESSION_MANAGER
userclientrc=$HOME/.startxwinrc
sysclientrc=/etc/X11/xinit/startxwinrc

userserverrc=$HOME/.xserverrc
sysserverrc=/etc/X11/xinit/xserverrc
defaultclient=xterm
defaultserver=/usr/bin/XWin
defaultclientargs=""
defaultserverargs="-listen tcp"
defaultdisplay=":0"
clientargs=""
serverargs=""
vtarg=""
display=""
enable_xauth=1


# Automatically determine an unused $DISPLAY
d=0
while true ; do
  [ -e "/tmp/.X$d-lock" -o -S "/tmp/.X11-unix/X$d" ] || break
  kill -0 `cat /tmp/.X$d-lock` 2>/dev/null || break
  d=$(($d + 1))
done
defaultdisplay=":$d"
unset d

whoseargs="client"
while [ x"$1" != x ]; do
  case "$1" in
    # '' required to prevent cpp from treating "/*" as a C comment.
    /''*|\./''*)
      if [ "$whoseargs" = "client" ]; then
        if [ x"$client" = x ] && [ x"$clientargs" = x ]; then
          client="$1"
        else
          clientargs="$clientargs $1"
        fi
      else
        if [ x"$server" = x ] && [ x"$serverargs" = x ]; then
          server="$1"
        else
          serverargs="$serverargs $1"
        fi
      fi
      ;;
    --)
      whoseargs="server"
      ;;
    *)
      if [ "$whoseargs" = "client" ]; then
          clientargs="$clientargs $1"
      else
          # display must be the FIRST server argument
          if [ x"$serverargs" = x ] && \
        expr "$1" : ':[0-9][0-9]*$' > /dev/null 2>&1; then
        display="$1"
          else
        serverargs="$serverargs $1"
          fi
      fi
      ;;
  esac
  shift
done

# process client arguments
if [ x"$client" = x ]; then
  client=$defaultclient

  # For compatibility reasons, only use startxwinrc if there were no client command line arguments
  if [ x"$clientargs" = x ]; then
    if [ -f "$userclientrc" ] && [ ! -x "$userclientrc" ]; then
      echo "Skipping $userclientrc; present but not executable"
    fi
    if [ -x "$userclientrc" ]; then
      client=$userclientrc
    elif [ -f "$sysclientrc" ]; then
      client=$sysclientrc
    fi
  fi
fi

# if no client arguments, use defaults
if [ x"$clientargs" = x ]; then
  clientargs=$defaultclientargs
fi

# process server arguments
if [ x"$server" = x ]; then
  server=$defaultserver
  # For compatibility reasons, only use xserverrc if there were no server command line arguments
  if [ x"$serverargs" = x -a x"$display" = x ]; then
    if [ -f "$userserverrc" ]; then
      server=$userserverrc
    elif [ -f "$sysserverrc" ]; then
      server=$sysserverrc
    fi
  fi
fi

# if no server arguments, use defaults
if [ x"$serverargs" = x ]; then
  serverargs=$defaultserverargs
fi
serverargs="-multiwindow $serverargs"

# if no vt is specified add vtarg (which may be empty)
have_vtarg="no"
for i in $serverargs; do
  if expr match "$i" '^vt[0-9]\+$' > /dev/null; then
    have_vtarg="yes"
  fi
done
if [ "$have_vtarg" = "no" ]; then
  serverargs="$serverargs $vtarg"
fi

# if no display, use default
if [ x"$display" = x ]; then
  display=$defaultdisplay
fi

# The wsl CLI API changed between V1 and V2 when I used the insider edition.
# This has nothing to do with if the Linux is running in V1 or V2, only if the
# cli installed supports only V1 or V2 too, so I know which args to use.
if wsl -l -q > /dev/null 2>&1; then
  WSL_VERSION=2
else
  WSL_VERSION=1
fi

if [ x"$enable_xauth" = x1 ] ; then
  if [ x"$XAUTHORITY" = x ]; then
    XAUTHORITY=$HOME/.Xauthority
    export XAUTHORITY
  fi

  removelist=

  # set up default Xauth info for this machine
  case `uname` in
    Linux*)
      if [ -z "`hostname --version 2>&1 | grep GNU`" ]; then
        hostname=`hostname -f`
      else
        hostname=`hostname`
      fi
      ;;
    *)
      hostname=`hostname`
      ;;
  esac

  authdisplay=${display:-:0}

  mcookie=`/usr/bin/mcookie`

  if test x"$mcookie" = x; then
    echo "Couldn't create cookie"
    exit 1
  fi
  dummy=0

  # create a file with auth information for the server. ':0' is a dummy.
  xserverauthfile=$HOME/.serverauth.$$
  trap "rm -f '$xserverauthfile'" HUP INT QUIT ILL TRAP KILL BUS TERM
  touch "$xserverauthfile"
  xauth -q -f "$xserverauthfile" add ":${dummy}" . "${mcookie}"

  xserverauthfilequoted=$(echo ${xserverauthfile} | sed "s/'/'\\\\''/g")
  serverargs=${serverargs}" -auth '"${xserverauthfilequoted}"'"

  display_names=("${authdisplay}" "${hostname}${authdisplay}")

  OLD_IFS="${IFS}"
  IFS=$'\n' # Incase spaces are allowed, YOU KNOW WINDOWS!
  case "${WSL_VERSION}" in
    1)
      wsls=($(wsl -l | (iconv -f UCS-2LE -t ASCII//TRANSLIT || tr -d '\0') | sed -e '1d' -e 's/ (Default)//' |  tr -d '\r'))
      ;;
    2)
      wsls=($(wsl -l -q | (iconv -f UCS-2LE -t ASCII//TRANSLIT || tr -d '\0') |  tr -d '\r'))
      # WSL 2 can't use localhost, this netstat command works on normal and Sonicwall Mobile conntect
      # Other VPNs may not work as expected.
      # Works on WSL2 using Sonicwall Netextender when using VPN Kit
      # wsl2_accessible_ip="$(netstat -rvn | grep '^ *0\.0\.0\.0' | awk 'NR==1{print $4}')"
      wsl2_accessible_ip="$(ipconfig | sed -En '/vEthernet \(WSL\)/,/Default Gateway/s/.*IPv4 Address( *\.)* *: *//p' | tr -d '\r\n')"

      # This will not work right if multiple ethernet devices say WSL
      # You may want to use this line on your particualr computer setup
      # wsl2_accessible_ip="$(powershell "(Get-NetIPAddress -AddressFamily IPV4 -InterfaceAlias *WSL*).IPAddress" | tr -d '\r\n')"
      if [ -n "${wsl2_accessible_ip}" ]; then
        display_names+=("${wsl2_accessible_ip}${authdisplay}")
      fi
      ;;
    *)
      echo "Unknown version of WSL detected"
      exit 123
      ;;
  esac
  IFS="${OLD_IFS}"
  unset OLD_IFS

  # now add the same credentials to the client authority file
  # if '$displayname' already exists do not overwrite it as another
  # server man need it. Add them to the '$xserverauthfile' instead.
  for displayname in "${display_names[@]}"; do
    authcookie=`xauth list "${displayname}" | \
                sed -n "s/.*${displayname}[[:space:]*].*[[:space:]*]//p"` 2>/dev/null;

    if [ "z${authcookie}" = "z" ] ; then
      xauth -q add "${displayname}" . "${mcookie}"
      for wsl in "${wsls[@]}"; do
        wsl -d "${wsl}" sh -c "
          if command -v xauth > /dev/null 2>&1; then
            if [ -n \"\${WSL_INTEROP-}\" ]; then
              xauth -q add '${wsl2_accessible_ip}${display}' . '${mcookie}'
            fi
            xauth -q add '${displayname}' . '${mcookie}'
          fi"
      done
      removelist="${display_names[*]}"
    else
      dummy=$(($dummy+1));
      xauth -q -f "$xserverauthfile" add ":${dummy}" . "${authcookie}"

      for wsl in "${wsls[@]}"; do
        wsl -d "${wsl}" sh -c "
          if command -v xauth > /dev/null 2>&1; then
            if [ -n \"\${WSL_INTEROP-}\" ]; then
              xauth -q -f '${xserverauthfile}' add '${wsl2_accessible_ip}${dummy}' . '${mcookie}'
            fi
            xauth -q -f '${xserverauthfile}' add ':${dummy}' . '${authcookie}'
          fi"
      done
    fi
  done
fi

# Copy to WSLs' home
for wsl in "${wsls[@]}"; do
  wsl -d "${wsl}" sh -c '
    # If running WSL2
    if [ -n "${WSL_INTEROP-}" ]; then'"
      echo 'export DISPLAY=${wsl2_accessible_ip}${display}' > ~/.displayrc
    else
      echo 'export DISPLAY=${display}' > ~/.displayrc
    fi
  "
done

# Copy to cygwin's home
echo "export DISPLAY=${display}" > ~/.displayrc

# Copy to Windows home, used by mingw et al.
echo "export DISPLAY=${display}" > "${USERPROFILE}/.displayrc"

echo "Starting xinit..."
eval xinit \"$client\" $clientargs -- \"$server\" $display $serverargs
retval=$?
echo "Cleaning up xinit..."

if [ x"$enable_xauth" = x1 ] ; then
  if [ x"$removelist" != x ]; then
    xauth remove $removelist
    for wsl in "${wsls[@]}"; do
      wsl -d "${wsl}" sh -c "if command -v xauth > /dev/null 2>&1; then xauth remove $removelist; fi"
    done
  fi
  if [ x"$xserverauthfile" != x ]; then
    rm -f "$xserverauthfile"
    for wsl in "${wsls[@]}"; do
      wsl -d "${wsl}" rm -f "$xserverauthfile"
    done
  fi
fi
exit $retval

system_tray.png

windows_find_shortcut.png

Thanks! Turns out there was a Windows Defender rule blocking the connection. I don't recall ever setting it but it's possible I answered "no" long ago. Deleting that rule allowed your solution to work, with the one tweak discussed above about locating the wsl.exe executable.

Windows 11 can finally stop using this script: https://docs.nvidia.com/cuda/wsl-user-guide/index.html#wsl2-system-requirements
Windows 10 still needs insider program, which isn't for everyone :(