wine/tools/wineinstall

#!/bin/bash
# WINE Installation script
# Can do almost everything from compiling to configuring...
#
# Copyright 1999 Ove Kåven
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# History:
# Mar 31 1999 - Ove Kåven
#  First version
# Dec 9 1999 - Ove Kåven
#  require Xpm
# Feb 25 2000 - Ove Kåven
#  auto-add /usr/local/lib to /etc/ld.so.conf
# Mar 2 2000 - Ove Kåven
#  source rather than grep config.cache
#  use sourced config.cache to start ldconfig
#  reconfigure if config.cache doesn't exist
# Mar 30 2000 - Ove Kåven
#  autoconfigure no-windows installs
#  do not install registry on real-windows installs
#  some support for binary package installs
#  set and tell user about LD_LIBRARY_PATH if necessary
#  set EXTRA_LD_LIBRARY_PATH in wine.conf
# Apr 9 2000 - Ove Kåven
#  make root's registry global (system-default)
# May 9 2000 - Ove Kåven
#  use ttydrv when running regapi, so we don't have to run from X
#  change debugger path in registry
# Oct 29 2000 - Ove Kåven
#  added --enable-opengl to default confargs
#  added conf_question, conf_yesno_answer, and conf_string_answer functions
#  added DEFCAT variable
# (later that day...)
#  added conf_reset_question function
#  added file existence checks to the registry copying
#  fixed problem with no-windows directory creation
#  some text reformatting from Eric Maryniak
# Jan 5 2000 - Chris Morgan
#  use default config file in /documentation/samples/config
#  replace .winerc with ~/.wine/config in printed text
#  added user question to convert .winerc file(if exists) or use the default
#    config file
#  add conf_question to allow root to install a local config file and
#    registry
# Jan 12 2000 - Chris Morgan
#  distinguish between creating local and global config files
#  display a message about the status of global config files
#  misc cleanups and reordering of questions
#  added check to see if wine is installed when we are running as a normal
#    user and print a message if wine cannot be found
# Feb 16 2002 - Adam D. Moss
#  Use config.status instead of config.cache to check whether we're
#    configured/compiled and to recreate the configuration
# Feb 20 2002 - Adam D. Moss
#  Partially revert previous changes, force configure to write an
#    old-style config.cache
# Mar 27 2002 - Chris Morgan
#  prevent the user from running wineinstall as root
#  add script commands so we su root for 'make install' and other commands
#    that require root access
#  add text to tell the user we need to run stuff as root so they don't
#    think we are trying to pull something funny
# Apr 14 2002 - Dustin Navea
#  Fix sed command when finding real-windows registry so it actually
#   accesses a file (~/.wine/config) instead of null ($CONF?!)
#  Added search for clean-install (not upgrade) Win2k registry
#  (next day, after some sleep)
#  Fix sed string when finding real-windows registry to actually find
#   windows partition name in [Drive C] section
#  it should now almost always find the windows partition and real-windows
#  registry (if not, let me know)
# Aug 29 2002 - Rok Mandeljc <rok.mandeljc@gimb.org>
#  -added two symlinks; windows/winhelp.exe and windows/winhlp32.exe because it seems
#   that some apps look for winhlp32.exe/winhelp to display help
#

#--- defaults (change these if you are a packager)
CONFARGS="--enable-opengl"    # configure args, e.g. --prefix=/usr --sysconfdir=/etc
prefix=/usr/local             # installation prefix
sysconfdir=$prefix/etc        # where wine.conf and the global registry are supposed to be
bindir=$prefix/bin            # where winelib apps will be (or are) installed
libdir=$prefix/lib            # where libwine.so will be (or is) installed
exdir=documentation/samples   # where the sample system.ini resides
GCONF=$sysconfdir/wine.conf   # default path of the wine.conf global config file
LCONF=~/.wine/config          # default path of the local config file
BINDIST=no                    # whether called from a binary package config script
DOGLOBALCONF=auto             # whether to autogenerate wine.conf
DOLOCALCONF=auto              # whether to autogenerate localconf
DOWCHK=auto                   # whether to autoconfigure existing-windows installation
DOWINE=auto                   # whether to autoconfigure no-windows installation
DOREG=auto                    # whether to install default registry
DOAPP=auto                    # whether to install applications, distributed with Wine
SYSREG=yes                    # whether to make root's registry global (system-default)
CONVCONF=no		      # whether we are converting an existing .winerc or not

# "make install" still installs the dlls into $libdir, but this may change in the future
# (DLLPATH should point to them if/when they are not in standard ld.so paths)
DLLPATH=$libdir/wine          # default path of the dll .so files (except libwine.so)

# having the Wine debugger launched automatically will be a plus for us
DEBUGGER=$bindir/winedbg      # the (installed) path of winedbg
HDEBUGGER=debugger/winedbg    # the (non-installed) path of winedbg

# this is only for existing-windows installs
WINECONF=tools/wineconf       # path to the wineconf perl script

# this is only for no-windows installs
WINEINI=$exdir/config         # path to the default wine config file (also used by wineconf)
WININI=/dev/null              # path to the default win.ini
SYSTEMINI=$exdir/system.ini   # path to the default system.ini
REGEDIT=$bindir/regedit       # path to the regedit winelib application
DEFREG=winedefault.reg        # path of the registry file to be fed to regedit
# CROOT=/var/wine             # path of the fake Drive C (asks user if not set)
DEFCAT=cat                    # program to cat $DEFREG with (some packages need zcat)
#--- end of defaults

# temporary files used by the installer
TMPCONF=/tmp/wineinstall.conf
TMPREG=/tmp/wineinstall.reg

# functions

function std_sleep {
  sleep 1
}

function conf_question {
  # parameters: $1 = importance, $2 = question-id, $3+ = message lines
  # the first two parameters can be used by e.g. debconf in debian packages
  # but here we just print the message
  shift 2
  echo
  local LINE="$1"
  while shift
  do {
    echo "$LINE"
    LINE="$1"
  }
  done
}

function conf_reset_question {
  # parameters: $1 = question-id
  # this is used to flush any cached answers and "already-displayed" flags
  shift # dummy command
}

function conf_yesno_answer {
  unset ANSWER
  while [ "$ANSWER" != 'yes' ] && [ "$ANSWER" != 'no' ]
  do {
    echo -n "$1"
    read ANSWER
  }
  done
}

function conf_string_answer {
  echo -n "$1"
  read ANSWER
}

function create_windows_directories {
  for tdir in "$CROOT/windows" "$CROOT/windows/system" "$CROOT/windows/system32" \
              "$CROOT/windows/Start Menu" "$CROOT/windows/Start Menu/Programs" \
              "$CROOT/Program Files" "$CROOT/Program Files/Common Files" \
              "$CROOT/windows/Profiles" "$CROOT/windows/Profiles/Administrator" \
              "$CROOT/windows/Fonts" "$CROOT/windows/Start Menu/Programs/Startup"
  do [ -d "$tdir" ] || mkdir "$tdir"
  done
  [ -f "$CROOT/windows/win.ini" ]    || cp "$WININI"    "$CROOT/windows/win.ini"
  [ -f "$CROOT/windows/system.ini" ] || cp "$SYSTEMINI" "$CROOT/windows/system.ini"
}

#creates symbolic link in windows directory to installed winelib application
#parameters:
# - name of the installed winelib application
# - full path to application in the winelib directory
function link_app {
  ln -sf $libdir/wine/$1.exe.so $2
}

#puts windows applications replacements to windows directories,
#configures them
function configure_wine_applications {
  link_app regedit      "$CROOT/windows/regedit.exe"
  link_app uninstaller  "$CROOT/windows/uninstall.exe"
  link_app wcmd         "$CROOT/windows/system32/cmd.exe"
  link_app control      "$CROOT/windows/system32/control.exe"
  link_app winhelp      "$CROOT/windows/system32/help.exe"
  link_app notepad      "$CROOT/windows/system32/notepad.exe"
  link_app progman      "$CROOT/windows/system32/progman.exe"
  link_app regsvr32     "$CROOT/windows/system32/regsvr32.exe"
  link_app winemine     "$CROOT/windows/system32/winmine.exe"
  link_app winver       "$CROOT/windows/system32/winver.exe"
  link_app winhelp      "$CROOT/windows/winhelp.exe"
  link_app winhelp      "$CROOT/windows/winhlp32.exe"
}

# startup...

echo "WINE Installer v0.73"
echo

if [ "$BINDIST" = 'no' ]
then {

  if ! [ -f configure ]
  then {
    echo "You're running this from the wrong directory."
    echo "Change to the Wine source's main directory and try again."
    exit 1
  }
  fi

  if [ `whoami` == 'root' ]
  then {
    echo "You are running wineinstall as root, this is not advisable. Please rerun as a user."
    echo "Aborting."
    exit 1
  }
  fi

  # check whether RPM installed, and if it is, remove any old wine rpm.
  hash rpm &>/dev/null
  RET=$?
  if [ $RET -eq 0 ]; then
    if [ -n "`rpm -qi wine 2>/dev/null|grep "^Name"`" ]; then
      echo "Warning: Old Wine RPM install detected. Do you want to remove it first?"
      conf_yesno_answer "(yes/no) "
      if [ "$ANSWER" = 'yes' ]; then
        echo "We need to remove the rpm as root, please enter your root password"
        echo
        echo Starting wine rpm removal...
        su -c "rpm -e wine; RET=$?"
        if [ $RET -eq 0 ]; then
          echo Done.
        else
          echo "FAILED. Probably you aren't installing as root."
          echo "Expect problems (library conflicts with existing install etc.)."
        fi
      else
        echo "Sorry, I won't install Wine when an rpm version is still installed."
        echo "(Wine support suffered from way too many conflicts between RPM"
        echo "and source installs)"
        echo "Have a nice day !"
        exit 1
      fi
    fi
  fi

  # check whether wine binary still available
  if [ -n "`which wine 2>/dev/null|grep '/wine'`" ]; then
    echo "Warning !! wine binary (still) found, which may indicate"
    echo "a (conflicting) previous installation."
    echo "You might want to abort and uninstall Wine first."
    std_sleep
  fi

  # run the configure script, if necessary

  if [ -f config.cache ] && [ -f Makefile ] && [ Makefile -nt configure ]
  then {
    echo
    echo "I see that WINE has already been configured, so I'll skip that."
    std_sleep
    # load configure results
    . ./config.cache
  }
  else {
    echo "Running configure..."
    echo
    if ! ./configure -C $CONFARGS
    then {
      echo
      echo "Configure failed, aborting install."
      rm -f config.cache
      exit 1
    }
    fi
    # load configure results
    . ./config.cache
    # make sure X was found
    eval "$ac_cv_have_x"
    if [ "$have_x" != "yes" ]
    then {
      echo "Install the X development headers and try again."
      rm -f config.cache
      exit 1
    }
    fi
  }
  fi

  # now do the compilation and install, we need to always do this because we
  # don't want the 'make install' command we might run to run 'make' as root
  if [ `whoami` != 'root' ]
  then {
    # ask the user if they want to build and install wine
    echo
    echo "We need to install wine as root user, do you want us to build wine,"
    echo "'su root' and install Wine?  Enter 'no' to continue without installing"
    conf_yesno_answer "(yes/no) "

    if [ "$ANSWER" = "yes" ]
    then {
      # start out with the basic command
      sucommand="make install"

      # if the user doesn't have $libdir in their ld.so.conf add this
      # to our sucommand string
      if [ -f /etc/ld.so.conf ]
      then
        if ! grep -qs "$libdir" /etc/ld.so.conf
        then {
          echo
          echo "$libdir doesn't exist in your /etc/ld.so.conf, it will be added"
          echo "when we perform the install..."
          sucommand="$sucommand;echo $libdir>>/etc/ld.so.conf"
        }
        fi
        # run ldconfig always just in case some updated files dont get linked
        sucommand="$sucommand;$ac_cv_path_LDCONFIG"
      fi

      echo

      echo "Compiling WINE. Grab a lunch or two, rent a video, or whatever,"
      echo "in the meantime..."
      echo
      std_sleep

      # try to just make wine, if this fails 'make depend' and try to remake
      if ! { make; }
      then {
        if ! { make depend && make; }
        then {
          echo
          echo "Compilation failed, aborting install."
          exit 1
        }
        fi
      }
      fi
      echo

      echo "Performing 'make install' as root to install binaries, enter root password"

      std_sleep

      if ! su root -c "$sucommand"
      then {
        echo
        echo "Either you entered an incorrect password or we failed to run"
        echo "'$sucommand' correctly."
        echo "If you didn't enter an incorrect password then please report this"
        echo "error and any steps to possibly reproduce it to"
        echo "http://bugs.winehq.com/"
        echo
        echo "Installation failed, aborting."
        exit 1
      }
      fi

      echo

      # see if wine is installed on the users system, if not prompt them
      # and then exit
      if [ ! `which wine` ]
      then
        echo "Could not find wine on your system.  Run wineinstall as root to install wine"
        echo "before re-running wineinstall as a user."
        echo
        echo "Exiting wineinstall"
        exit 1;
      fi
    }
    else {
      # user didn't want to install wine so tell them about running from the
      # current directory and set some stuff up for them

      # setup to run from current directory
      DLLPATH="$PWD/dlls"
      if [ -z "$LD_LIBRARY_PATH" ]
      then LD_LIBRARY_PATH="$PWD:$DLLPATH"
      else LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$PWD:$DLLPATH"
      fi
      export LD_LIBRARY_PATH
      DEBUGGER="$PWD/$HDEBUGGER"
      echo
      echo "NOTE! To run Wine without installing, you must set the environment variable"
      echo "LD_LIBRARY_PATH to $PWD:$DLLPATH"
      echo "in your logon scripts."
      echo
    }
    fi
  }
  fi # [ `whoami` != 'root' ]

}
fi # BINDIST

# now check whether we should generate wine.conf
if [ -z "$DOGLOBALCONF" ]
then
  DOGLOBALCONF=auto
fi

if [ "$DOGLOBALCONF" = 'auto' ]
then {
  # see if we already have a system wine.conf
  if [ ! -f $GCONF ] && [ `whoami` = 'root' ]
  then
    DOGLOBALCONF=no
    echo "Creation of a global config file is not supported in wineinstall at this"
    echo "time.  When the configuration architecture is cleaned up this functionality"
    echo "will be restored to wineinstall."
    echo
  fi
}
fi

if [ "$DOLOCALCONF" = 'auto' ]
then {
  # see if the user is root, if so, explicitly ask them if they want a
  # local config file
  if [ `whoami` = 'root' ]
  then
    echo "You are running as root.  Do you want a local config file,"
    echo "file, ~/.wine/config, created?"
    conf_yesno_answer "(yes/no) "
    DOLOCALCONF="$ANSWER"
  else
    # if the user has an existing config file ask them if they want us to
    # overwrite it, otherwise just ask them if they want to create one
    if [ -f "$LCONF" ]
    then
      echo "Found existing $LCONF, do you want to overwrite this"
      echo "existing Wine configuration file?"
      conf_yesno_answer "(yes/no) "
      DOLOCALCONF="$ANSWER"
      echo
      if [ "$ANSWER" = "yes" ]
      then
      {
        echo "Would you like to make a backup of this old config file?"
        conf_yesno_answer "(yes/no) "
        echo
        if [ "$ANSWER" = "yes" ]
        then
        {
          echo "Renaming $LCONF to $LCONF.old"
          mv -f "$LCONF" "$LCONF.old"
          echo
        }
        fi
      }
      fi
    else
    {
      echo "Create local config file ~/.wine/config?"
      conf_yesno_answer "(yes/no) "
      DOLOCALCONF="$ANSWER"
      echo
      if [ "$ANSWER" = 'no' ]
      then
        conf_question high need_root \
          "Aborting install. Try again as root to generate a system wine.conf."
        exit 1
      fi
    }
    fi
  fi
}
fi

# generate $TMPCONF from existing windows install, if any
if [ "$DOLOCALCONF" = 'yes' ]
then {
  if [ "$DOWCHK" = 'yes' ] || [ "$DOWCHK" = 'auto' ]
  then {
    echo -n "Searching for an existing Windows installation..."
    if ! $WINECONF -inifile "$WINEINI" > $TMPCONF 2>/dev/null
    then {
      rm -f $TMPCONF $TMPREG > /dev/null

      echo " not found. (no matching /etc/fstab mount entry found)"
      conf_question low do_without_windows \
       "Windows was not found on your system, so I assume you want" \
       "a Wine-only installation. Am I correct?"
      conf_yesno_answer "(yes/no) "
      if [ "$ANSWER" = 'no' ]
      then {
        conf_question high windows_not_found \
         "Aborting install. Make sure your Windows partition is mounted and try again," \
         "or create $LCONF manually by copying from $WINEINI and adapting the drive paths."
        exit 1
      }
      fi
      DOWINE=yes
    }
    else {
      echo " found."

      conf_reset_question windows_found
      conf_question low windows_found \
       "Created $LCONF using your existing Windows installation." \
       "You probably want to review the file, though."
      DOWINE=no
    }
    fi
  }
  elif [ "$DOWINE" = 'auto' ]
  then DOWINE=yes
  fi
}
elif [ "$DOWINE" = 'auto' ]
then
  DOWINE=no
fi

# setup a no-windows installation, if necessary
if [ "$DOWINE" = 'yes' ]
then {
  # set an appropriate DCROOT
  if [ `whoami` != 'root' ]
  then DCROOT=~/c
  else DCROOT=/c
  fi

  if [ -f ~/.winerc ]
  then {
    conf_question medium convert_config \
     "I found the old version Wine config file, .winerc, in your " \
     "home directory.  I can convert this to the new format or use the" \
     "new default Wine config file. Convert?"
    conf_yesno_answer "(yes/no) "
    if [ "$ANSWER" = 'yes' ]
    then {
      WINEINI=~/.winerc
      CONVCONF=yes
    }
    fi
  }
  else {

    conf_question low drivec_path \
     "Configuring Wine without Windows." \
     "Some fake Windows directories must be created, to hold any .ini files, DLLs," \
     "start menu entries, and other things your applications may need to install." \
     "Where would you like your fake C drive to be placed?"
    while [ -z "$CROOT" ]
    do {
      conf_string_answer "(default is $DCROOT) "
      [ -z "$ANSWER" ] && ANSWER="$DCROOT"
      if ! [ -d "$ANSWER" ]
      then {
        if mkdir -p "$ANSWER"
        then CROOT="$ANSWER"
        else
          echo "Directory $ANSWER can't be created !"
          conf_reset_question drivec_path
        fi
      }
      else CROOT="$ANSWER"
      fi
    }
    done
    echo "Configuring Wine for a no-windows install in $CROOT..."

    create_windows_directories
    configure_wine_applications
  }
  fi

  # create $LCONF using the default config file $WINEINI
  if [ "$DOLOCALCONF" = 'yes' ] && [ "$CONVCONF" = 'no' ]
  then {
    sed "s|\"Path\" = \"/c\"\$|\"Path\" = \"${CROOT}\"|" $WINEINI > $TMPCONF
    conf_reset_question default_config
    conf_question low default_config \
     "Created $LCONF using default Wine configuration." \
     "You probably want to review the file, though."
  }
  fi

  # now we really should install the registry
  if [ "$DOREG" = 'auto' ]
  then DOREG=yes
  fi
}
fi
echo

#install the local config file $LCONF
if [ "$DOLOCALCONF" = 'yes' ]
then
  if [ ! -w ~/.wine ]
  then
    mkdir ~/.wine
  fi

  if [ "$CONVCONF" = 'no' ]
  then
    cp $TMPCONF $LCONF > /dev/null
  fi
else
  DOREG=no
fi

#install the global config file $GCONF
if [ "$DOGLOBALCONF" = 'yes' ]
then
  if [ ! -f $sysconfdir ]
  then
    mkdir -p $sysconfdir
  fi

  cp $TMPCONF $GCONF > /dev/null
fi

# check whether we need to install default registry
# (not to be done if windows registry exists)
if [ "$DOREG" = 'auto' ]
then {
  CROOT=`sed -n '/^\[Drive C\]$/,/^\[.*\]$/ s/^\"Path\" = \"\(.*\)\"/\1/p' $LCONF`
  echo "Checking for real Windows registry..."
  if [ -f "$CROOT/windows/system.dat" ]
  then DOREG=no
  elif [ -f "$CROOT/windows/system32/config/system" ]
  then DOREG=no
  elif [ -f "$CROOT/WINNT/system32/config/system" ]
  then DOREG=no
  else DOREG=yes
  fi
  if [ "$DOREG" = 'yes' ]
  then echo "Not found, default Wine registry will be installed."
  else echo "Windows registry found, will not install default Wine registry."
  fi
  echo
}
fi

# install default registry entries
if [ "$DOREG" = 'yes' ]
then {
  if [ "$BINDIST" = 'no' ]
  then {
    echo "Compiling regedit..."
    (cd programs/regedit; make)
    echo
  }
  fi
  echo "Preparing to install default Wine registry entries..."

  # edit config files so we don't have to run regedit under X
  if [ "$CONVCONF" = 'yes' ]
  then
    mv $WINEINI $WINEINI.new
    sed "s/GraphicsDriver=.*/GraphicsDriver=ttydrv/" $WINEINI.new > $WINEINI
  else
    mv $LCONF $LCONF.new
    sed "s/\"GraphicsDriver\" = .*/\"GraphicsDriver\" = \"ttydrv\"/" $LCONF.new > $LCONF
  fi

  # create a temporary wineinstall.reg with fixed debugger path
  $DEFCAT $DEFREG | sed "s|debugger/winedbg|${DEBUGGER}|" > $TMPREG

  echo "Installing default Wine registry entries..."
  echo
  if ! $REGEDIT $TMPREG > /dev/null
  then {
    rm -f $TMPREG
    echo "Registry install failed."
    conf_reset_question regedit_error
    conf_question high regedit_error
    exit 1
  }
  else {
    # if we are converting from a .winerc file, running regedit once
    # will ONLY convert .winerc -> ~/.wine/config, it will not import the
    # registry data.  so if we are converting we need to run regedit twice
    if [ "$CONVCONF" = 'yes' ]
    then
      if ! $REGEDIT $TMPREG > /dev/null
      then
        rm -f $TMPREG
        echo "Registry install failed."
        conf_reset_question regedit_error
        conf_question high regedit_error
        exit 1
      else
        echo
        echo "Registry entries successfully installed."
      fi
    else
      echo
      echo "Registry entries successfully installed."
    fi
  }
  fi
  rm -f $TMPREG
  if [ "$SYSREG" = 'auto' ]
  then SYSREG=yes
  fi

  # if we converted we need to change the graphics driver back and
  # restore the original .winerc file
  if [ "$CONVCONF" = 'yes' ]
  then
     mv $WINEINI.new $WINEINI
  fi

  sed "s/\"GraphicsDriver\" = .*/\"GraphicsDriver\" = \"x11drv\"/" $LCONF > $LCONF.new
  mv $LCONF.new $LCONF
}
fi

# make root's registry global, if desired
if [ `whoami` = 'root' ] && [ "$DOREG" = 'yes' ] && [ "$SYSREG" = 'yes' ]
then {
  [ -d ~/.wine ] || mkdir ~/.wine
  if ! [ -f $sysconfdir/wine.userreg ]
  then {
    echo "Linking root's user registry hive to the global registry..."
    [ -f ~/.wine/wine.userreg ] && cp ~/.wine/wine.userreg $sysconfdir/wine.userreg
    ln -sf $sysconfdir/wine.userreg ~/.wine/wine.userreg
  }
  fi
  if ! [ -f $sysconfdir/wine.systemreg ]
  then {
    echo "Linking root's system registry hive to the global registry..."
    [ -f ~/.wine/system.reg ] && cp ~/.wine/system.reg $sysconfdir/wine.systemreg
    ln -sf $sysconfdir/wine.systemreg ~/.wine/system.reg
  }
  fi
}
fi

# cleanup any temporary files that may remain
if [ -f $TMPCONF ]
then rm -f $TMPCONF
fi
if [ -f $TMPREG ]
then rm -f $TMPREG
fi


# it's a wrap
echo
echo "Installation complete for now. Good luck (this is still alpha software)."
echo "If you have problems with WINE, please read the documentation first,"
echo "as many kinds of potential problems are explained there."

exit 0