#!/bin/sh

 # This script starts an instance of Xvfb, the "fake" X server, runs a command

 # with that server available, and kills the X server when done.  The return

 # value of the command becomes the return value of this script.

 #

 # If anyone is using this to build a Debian package, make sure the package

 # Build-Depends on xvfb and xauth.

 set -e

 PROGNAME=xvfb-run

 SERVERNUM=99

 AUTHFILE=

 ERRORFILE=/dev/null

 XVFBARGS="-screen 0 640x480x8"

 LISTENTCP="-nolisten tcp"

 XAUTHPROTO=.

 # Query the terminal to establish a default number of columns to use for

 # displaying messages to the user.  This is used only as a fallback in the event

 # the COLUMNS variable is not set.  ($COLUMNS can react to SIGWINCH while the

 # script is running, and this cannot, only being calculated once.)

 DEFCOLUMNS=$(stty size 2>/dev/null | awk '{print $2}') || true

 if ! expr "$DEFCOLUMNS" : "[[:digit:]]\+$" >/dev/null 2>&1; then

     DEFCOLUMNS=80

 fi

 # Display a message, wrapping lines at the terminal width.

 message () {

     echo "$PROGNAME: $*" | fmt -t -w ${COLUMNS:-$DEFCOLUMNS}

 }

 # Display an error message.

 error () {

     message "error: $*" >&2

 }

 # Display a usage message.

 usage () {

     if [ -n "$*" ]; then

         message "usage error: $*"

     fi

     cat <<EOF

 Usage: $PROGNAME [OPTION ...] COMMAND

 Run COMMAND (usually an X client) in a virtual X server environment.

 Options:

 -a        --auto-servernum          try to get a free server number, starting at

                                     --server-num

 -e FILE   --error-file=FILE         file used to store xauth errors and Xvfb

                                     output (default: $ERRORFILE)

 -f FILE   --auth-file=FILE          file used to store auth cookie

                                     (default: ./.Xauthority)

 -h        --help                    display this usage message and exit

 -n NUM    --server-num=NUM          server number to use (default: $SERVERNUM)

 -l        --listen-tcp              enable TCP port listening in the X server

 -p PROTO  --xauth-protocol=PROTO    X authority protocol name to use

                                     (default: xauth command's default)

 -s ARGS   --server-args=ARGS        arguments (other than server number and

                                     "-nolisten tcp") to pass to the Xvfb server

                                     (default: "$XVFBARGS")

 EOF

 }

 # Find a free server number by looking at .X*-lock files in /tmp.

 find_free_servernum() {

     # Sadly, the "local" keyword is not POSIX.  Leave the next line commented in

     # the hope Debian Policy eventually changes to allow it in /bin/sh scripts

     # anyway.

     #local i

     i=$SERVERNUM

     while [ -f /tmp/.X$i-lock ]; do

         i=$(($i + 1))

     done

     echo $i

 }

 # Clean up files

 clean_up() {

     if [ -e "$AUTHFILE" ]; then

         XAUTHORITY=$AUTHFILE xauth remove ":$SERVERNUM" >>"$ERRORFILE" 2>&1

     fi

     if [ -n "$XVFB_RUN_TMPDIR" ]; then

         if ! rm -r "$XVFB_RUN_TMPDIR"; then

             error "problem while cleaning up temporary directory"

             exit 5

         fi

     fi

     if [ -n "$XVFBPID" ]; then

         kill "$XVFBPID" >>"$ERRORFILE" 2>&1

     fi

 }

 # Parse the command line.

 ARGS=$(getopt --options +ae:f:hn:lp:s:w: \

        --long auto-servernum,error-file:,auth-file:,help,server-num:,listen-tcp,xauth-protocol:,server-args:,wait: \

        --name "$PROGNAME" -- "$@")

 GETOPT_STATUS=$?

 if [ $GETOPT_STATUS -ne 0 ]; then

     error "internal error; getopt exited with status $GETOPT_STATUS"

     exit 6

 fi

 eval set -- "$ARGS"

 while :; do

     case "$1" in

         -a|--auto-servernum) SERVERNUM=$(find_free_servernum); AUTONUM="yes" ;;

         -e|--error-file) ERRORFILE="$2"; shift ;;

         -f|--auth-file) AUTHFILE="$2"; shift ;;

         -h|--help) SHOWHELP="yes" ;;

         -n|--server-num) SERVERNUM="$2"; shift ;;

         -l|--listen-tcp) LISTENTCP="" ;;

         -p|--xauth-protocol) XAUTHPROTO="$2"; shift ;;

         -s|--server-args) XVFBARGS="$2"; shift ;;

         -w|--wait) shift ;;

         --) shift; break ;;

         *) error "internal error; getopt permitted \"$1\" unexpectedly"

            exit 6

            ;;

     esac

     shift

 done

 if [ "$SHOWHELP" ]; then

     usage

     exit 0

 fi

 if [ -z "$*" ]; then

     usage "need a command to run" >&2

     exit 2

 fi

 if ! which xauth >/dev/null; then

     error "xauth command not found"

     exit 3

 fi

 # tidy up after ourselves

 trap clean_up EXIT

 # If the user did not specify an X authorization file to use, set up a temporary

 # directory to house one.

 if [ -z "$AUTHFILE" ]; then

     XVFB_RUN_TMPDIR="$(mktemp -d -t $PROGNAME.XXXXXX)"

     # Create empty file to avoid xauth warning

     AUTHFILE=$(tempfile -n "$XVFB_RUN_TMPDIR/Xauthority")

 fi

 # Start Xvfb.

 MCOOKIE=$(mcookie)

 tries=10

 while [ $tries -gt 0 ]; do

     tries=$(( $tries - 1 ))

     XAUTHORITY=$AUTHFILE xauth source - << EOF >>"$ERRORFILE" 2>&1

 add :$SERVERNUM $XAUTHPROTO $MCOOKIE

 EOF

     # handle SIGUSR1 so Xvfb knows to send a signal when it's ready to accept

     # connections

     trap : USR1

     (trap '' USR1; exec Xvfb ":$SERVERNUM" $XVFBARGS $LISTENTCP -auth $AUTHFILE >>"$ERRORFILE" 2>&1) &

     XVFBPID=$!

     wait || :

     if kill -0 $XVFBPID 2>/dev/null; then

         break

     elif [ -n "$AUTONUM" ]; then

         # The display is in use so try another one (if '-a' was specified).

         SERVERNUM=$((SERVERNUM + 1))

         SERVERNUM=$(find_free_servernum)

         continue

     fi

     error "Xvfb failed to start" >&2

     XVFBPID=

     exit 1

 done

 # Start the command and save its exit status.

 set +e

 DISPLAY=:$SERVERNUM XAUTHORITY=$AUTHFILE "$@" 2>&1

 RETVAL=$?

 set -e

 # Return the executed command's exit status.

 exit $RETVAL

 # vim:set ai et sts=4 sw=4 tw=80: