/etc/X11/Xsession

1. !/bin/sh
3. /etc/X11/Xsession
5. global Xsession file -- used by display managers and xinit (startx)

1. $Id: Xsession 967 2005-12-27 07:20:55Z dnusinow $

set -e

PROGNAME=Xsession

message () {

 # pretty-print messages of arbitrary length; use xmessage if it
 # is available and $DISPLAY is set
 MESSAGE="$PROGNAME: $*"
 echo "$MESSAGE" | fold -s -w ${COLUMNS:-80} >&2
 if [ -n "$DISPLAY" ] && which xmessage > /dev/null 2>&1; then
   echo "$MESSAGE" | fold -s -w ${COLUMNS:-80} | xmessage -center -file -
 fi

}

message_nonl () {

 # pretty-print messages of arbitrary length (no trailing newline); use
 # xmessage if it is available and $DISPLAY is set
 MESSAGE="$PROGNAME: $*"
 echo -n "$MESSAGE" | fold -s -w ${COLUMNS:-80} >&2;
 if [ -n "$DISPLAY" ] && which xmessage > /dev/null 2>&1; then
   echo -n "$MESSAGE" | fold -s -w ${COLUMNS:-80} | xmessage -center -file -
 fi

} errormsg () {

 # exit script with error
 message "$*"
 exit 1

}

internal_errormsg () {

 # exit script with error; essentially a "THIS SHOULD NEVER HAPPEN" message
 # One big call to message() for the sake of xmessage; if we had two then
 # the user would have dismissed the error we want reported before seeing the
 # request to report it.
 errormsg "$*" \
          "Please report the installed version of the \"x11-common\"" \
          "package and the complete text of this error message to" \
          "<debian-x@lists.debian.org>."

}

1. initialize variables for use by all session scripts

OPTIONFILE=/etc/X11/Xsession.options

SYSRESOURCES=/etc/X11/Xresources USRRESOURCES=$HOME/.Xresources

SYSSESSIONDIR=/etc/X11/Xsession.d USERXSESSION=$HOME/.xsession USERXSESSIONRC=$HOME/.xsessionrc ALTUSERXSESSION=$HOME/.Xsession ERRFILE=$HOME/.xsession-errors

1. attempt to create an error file; abort if we cannot

if (umask 077 && touch "$ERRFILE") 2> /dev/null && [ -w "$ERRFILE" ] &&

 [ ! -L "$ERRFILE" ]; then
 chmod 600 "$ERRFILE"

elif ERRFILE=$(tempfile 2> /dev/null); then

 if ! ln -sf "$ERRFILE" "${TMPDIR:=/tmp}/xsession-$USER"; then
   message "warning: unable to symlink \"$TMPDIR/xsession-$USER\" to" \
            "\"$ERRFILE\"; look for session log/errors in" \
            "\"$TMPDIR/xsession-$USER\"."
 fi

else

 errormsg "unable to create X session log/error file; aborting."

fi

1. truncate ERRFILE if it is too big to avoid disk usage DoS

if [ "`stat -c%s \"$ERRFILE\"`" -gt 500000 ]; then

 T=`mktemp -p "$HOME"`
 tail -c 500000 "$ERRFILE" > "$T" && mv -f "$T" "$ERRFILE" || rm -f "$T"

fi

exec >>"$ERRFILE" 2>&1

echo "$PROGNAME: X session started for $LOGNAME at $(date)"

1. sanity check; is our session script directory present?

if [ ! -d "$SYSSESSIONDIR" ]; then

 errormsg "no \"$SYSSESSIONDIR\" directory found; aborting."

fi

1. Attempt to create a file of non-zero length in /tmp; a full filesystem can
2. cause mysterious X session failures. We do not use touch, :, or test -w
3. because they won't actually create a file with contents. We also let standard
4. error from tempfile and echo go to the error file to aid the user in
5. determining what went wrong.

WRITE_TEST=$(tempfile) if ! echo "*" >>"$WRITE_TEST"; then

 message "warning: unable to write to ${WRITE_TEST%/*}; X session may exit" \
         "with an error"

fi rm -f "$WRITE_TEST"

1. use run-parts to source every file in the session directory; we source
2. instead of executing so that the variables and functions defined above
3. are available to the scripts, and so that they can pass variables to each
4. other

SESSIONFILES=$(run-parts --list $SYSSESSIONDIR) if [ -n "$SESSIONFILES" ]; then

 set +e
 for SESSIONFILE in $SESSIONFILES; do
   . $SESSIONFILE
 done
 set -e

fi

exit 0

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