Subject: wish: package xvfb-run
From: "Dr. Arne Babenhauserheide" <[email-masked]>
To: [email-masked]
Date: Mon, 08 Mar 2021 01:57:33 +0100
List-Id: <debbugs-submit.debbugs.gnu.org>

User-agent: mu4e 1.4.15; emacs 27.1
(emacs:30177): dbind-WARNING **: 01:46:31.849: Could not open X display

http://deb.debian.org/debian/pool/main/x/xorg-server/xorg-server_1.20.10-3.diff.gz

+Usage: $PROGNAME [OPTION ...] COMMAND
+Options:
+DISPLAY=:$SERVERNUM XAUTHORITY=$AUTHFILE "$@"
Dear Guix hackers,

One of my main tools for running graphical programs as part of my build
pipelines is xvfb-run. Since it is not packaged in Guix, I’ve resorted
to manual workarounds, but these have annoying drawbacks:

Xvfb :3 -screen 0 1024x768x16 & time DISPLAY=:3 HOME=/path/to/project/.emacs.d emacs …

I now get errors about the maximum number of clients reached, because
the Xvfb does not get reaped after the build:
Maximum number of clients reached
Therefore I would ask whether it would be possible to package xvfb-run.
It is provided as part of the patches of the xorg-package in Debian:

The included xvfb-run and xvfb-run.1:

--- xorg-server-1.20.10.orig/debian/local/xvfb-run
+++ xorg-server-1.20.10/debian/local/xvfb-run
@@ -0,0 +1,191 @@
+#!/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 1280x1024x24"
+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 $2}') || true
+case "$DEFCOLUMNS" in
+    *[!0-9]*|'') DEFCOLUMNS=80 ;;
+esac
+
+# 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
+Run COMMAND (usually an X client) in a virtual X server environment.
+-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 "$*" ]; then
+    usage "need a command to run" >&2
+    exit 2
+fi
+
+if ! command -v xauth >/dev/null; then
+    error "xauth command not found"
+    exit 3
+fi
+
+# tidy up after ourselves
+trap clean_up EXIT
+
+# If the user did not specify an X authorization file to use, set up a temporary
+# directory to house one.
+if [ -z "$AUTHFILE" ]; then
+    XVFB_RUN_TMPDIR="$(mktemp -d -t $PROGNAME.XXXXXX)"
+    AUTHFILE="$XVFB_RUN_TMPDIR/Xauthority"
+    # Create empty file to avoid xauth warning
+    touch "$AUTHFILE"
+fi
+
+# Start Xvfb.
+MCOOKIE=$(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
+RETVAL=$?
+set -e
+
+# Return the executed command's exit status.
+exit $RETVAL
+
+# vim:set ai et sts=4 sw=4 tw=80:
--- xorg-server-1.20.10.orig/debian/local/xvfb-run.1
+++ xorg-server-1.20.10/debian/local/xvfb-run.1
@@ -0,0 +1,275 @@
+.\" Copyright 1998-2004 Branden Robinson <[email-masked]>.
+.\"
+.\" This is free software; you may redistribute it and/or modify
+.\" it under the terms of the GNU General Public License as
+.\" published by the Free Software Foundation; either version 2,
+.\" or (at your option) any later version.
+.\"
+.\" This is distributed in the hope that it will be useful, but
+.\" WITHOUT ANY WARRANTY; without even the implied warranty of
+.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+.\" GNU General Public License for more details.
+.\"
+.\" You should have received a copy of the GNU General Public License with
+.\" the Debian operating system, in /usr/share/common-licenses/GPL;  if
+.\" not, write to the Free Software Foundation, Inc., 59 Temple Place,
+.\" Suite 330, Boston, MA 02111-1307 USA
+.\"
+.\" We need the URL macro from groff's www macro package, but also want
+.\" things to work all right for people who don't have it.  So we define
+.\" our own URL macro and let the www macro package override it if it's
+.\" available.
+.de URL
+\\$2 \(laURL: \\$1 \(ra\\$3
+..
+.if \n[.g] .mso www.tmac
+.TH xvfb\-run 1 "2004\-11\-12" "Debian Project"
+.SH NAME
+xvfb\-run \- run specified X client or command in a virtual X server environment
+.SH SYNOPSIS
+.B xvfb\-run
+[
+.I options
+]
+.I command
+.SH DESCRIPTION
+.B xvfb\-run
+is a wrapper for the
+.BR Xvfb (1x)
+command which simplifies the task of running commands (typically an X
+client, or a script containing a list of clients to be run) within a virtual
+X server environment.
+.PP
+.B xvfb\-run
+sets up an X authority file (or uses an existing user\-specified one),
+writes a cookie to it (see
+.BR xauth (1x))
+and then starts the
+.B Xvfb
+X server as a background process.
+The process ID of
+.B Xvfb
+is stored for later use.
+The specified
+.I command
+is then run using the X display corresponding to the
+.B Xvfb
+server
+just started and the X authority file created earlier.
+.PP
+When the
+.I command
+exits, its status is saved, the
+.B Xvfb
+server is killed (using the process ID stored earlier), the X authority
+cookie removed, and the authority file deleted (if the user did not specify
+one to use).
+.B xvfb\-run
+then exits with the exit status of
+.IR command .
+.PP
+.B xvfb\-run
+requires the
+.B xauth
+command to function.
+.SH OPTIONS
+.TP
+.B \-a\fR,\fB \-\-auto\-servernum
+Try to get a free server number, starting at 99, or the argument to
+.BR \-\-server\-num .
+.TP
+.BI \-e\  file \fR,\fB\ \-\-error\-file= file
+Store output from
+.B xauth
+and
+.B Xvfb
+in
+.IR file .
+The default is
+.IR /dev/null .
+.TP
+.BI \-f\  file \fR,\fB\ \-\-auth\-file= file
+Store X authentication data in
+.IR file .
+By default, a temporary directory called
+.IR xvfb\-run. PID
+(where PID is the process ID of
+.B xvfb\-run
+itself) is created in the directory specified by the environment variable
+.B TMPDIR
+(or
+.I /tmp
+if that variable is null or unset), and the
+.BR tempfile (1)
+command is used to create a file in that temporary directory called
+.IR Xauthority .
+.TP
+.B \-h\fR,\fB \-\-help
+Display a usage message and exit.
+.TP
+.BI \-n\  servernumber \fR,\fB\ \-\-server\-num= servernumber
+Use
+.I servernumber
+as the server number (but see the
+.B \-a\fR,\fB \-\-auto\-servernum
+option above).
+The default is 99.
+.TP
+.B \-l\fR,\fB \-\-listen\-tcp
+Enable TCP port listening in the X server.
+For security reasons (to avoid denial\-of\-service attacks or exploits),
+TCP port listening is disabled by default.
+.TP
+.BI \-p\  protocolname \fR,\fB\ \-\-xauth\-protocol= protocolname
+Use
+.I protocolname
+as the X authority protocol to use.
+The default is \(oq.\(cq, which
+.B xauth
+interprets as its own default protocol, which is MIT\-MAGIC\-COOKIE\-1.
+.TP
+.BI \-s\  arguments \fR,\fB\ \-\-server\-args= arguments
+Pass
+.I arguments
+to the
+.B Xvfb
+server.
+Be careful to quote any whitespace characters that may occur within
+.I arguments
+to prevent them from regarded as separators for
+.BR xvfb\-run 's
+own arguments.
+Also, note that specification of \(oq\-nolisten tcp\(cq in
+.I arguments
+may override the function of
+.BR xvfb\-run 's
+own
+.B \-l\fR,\fB \-\-listen\-tcp
+option, and that specification of the server number (e.g., \(oq:1\(cq) may
+be ignored because of the way the X server parses its argument list.
+Use the
+.B xvfb\-run
+option
+.BI \-n\  servernumber \fR,\fB\ \-\-server\-num= servernumber
+to achieve the latter function.
+The default is \(oq\-screen 0 1280x1024x24\(cq.
+.TP
+.BI \-w\  delay \fR,\fB\ \-\-wait= delay
+Ignored for compatibility with earlier versions.
+.SH ENVIRONMENT
+.TP
+.B COLUMNS
+indicates the width of the terminal device in character cells.
+This value is used for formatting diagnostic messages.
+If not set, the terminal is queried using
+.BR stty (1)
+to determine its width.
+If that fails, a value of \(oq80\(cq is assumed.
+.TP
+.B TMPDIR
+specifies the directory in which to place
+.BR xvfb\-run 's
+temporary directory for storage of the X authority file; only used if the
+.B \-f
+or
+.B \-\-auth\-file
+options are not specified.
+.SH "OUTPUT FILES"
+.PP
+Unless the
+.B \-f
+or
+.B \-\-auth\-file
+options are specified, a temporary
+directory and file within it are created (and deleted) to store the X
+authority cookies used by the
+.B Xvfb
+server and client(s) run under it.
+See
+.BR tempfile (1).
+If \-f or \-\-auth\-file are used, then the specified X authority file is
+only written to, not created or deleted (though
+.B xauth
+creates an authority file itself if told to use use that does not already
+exist).
+.PP
+An error file with a user\-specified name is also created if the
+.B \-e
+or
+.B \-\-error\-file
+options are specified; see above.
+.SH "EXIT STATUS"
+.B xvfb\-run
+uses its exit status as well as output to standard error to communicate
+diagnostics.
+The exit status of \(oq1\(cq is not used, and should be interpreted as failure
+of the specified command.
+.TP
+0
+.B xvfb\-run
+only uses this exit status if the
+.B \-h\fR,\fB \-\-help
+option is given.
+In all other situations, this may be interpreted as success of the specified
+command.
+.TP
+2
+No command to run was specified.
+.TP
+3
+The
+.B xauth
+command is not available.
+.TP
+4
+The temporary directory that was going to be used already exists; since
+.B xvfb\-run
+produces a uniquely named directory, this may indicate an attempt by another
+process on the system to exploit a temporary file race condition.
+.TP
+5
+A problem was encountered while cleaning up the temporary directory.
+.TP
+6
+A problem was encountered while using
+.BR getopt (1)
+to parse the command\-line arguments.
+.SH EXAMPLES
+.TP
+.B xvfb\-run \-\-auto\-servernum \-\-server\-num=1 xlogo
+runs the
+.BR xlogo (1x)
+demonstration client inside the
+.B Xvfb
+X server on the first available server number greater than or equal to 1.
+.TP
+.B xvfb\-run \-\-server\-args="\-screen 0 1024x768x24" ico \-faces
+runs the
+.BR ico (1x)
+demonstration client (and passes it the
+.B \-faces
+argument) inside the
+.B Xvfb
+X server, configured with a root window of 1024 by 768 pixels and a color
+depth of 24 bits.
+.PP
+Note that the demo X clients used in the above examples will not exit on
+their own, so they will have to be killed before
+.B xvfb\-run
+will exit.
+.SH BUGS
+See
+.URL "https://bugs.debian.org/xvfb" "the Debian Bug Tracking System" .
+If you wish to report a bug in
+.BR xvfb\-run ,
+please use the 
+.BR reportbug (1)
+command.
+.SH AUTHOR
+.B xvfb\-run
+was written by Branden Robinson and Jeff Licquia with sponsorship from
+Progeny Linux Systems.
+.SH "SEE ALSO"
+.BR Xvfb (1x),
+.BR xauth (1x)
+.\" vim:set et tw=80:

Best wishes,
Arne
-- 
Unpolitisch sein
heißt politisch sein
ohne es zu merken
Date: Mon, 08 Mar 2021 01:57:32 +0100
Message-ID: <[email-masked]>