Upgrading Packages

The process of upgrading a package is very different from that of overwriting a package. While there are special tools to support the upgrade of standard packages delivered as part of the Solaris OS, an unbundled package can be designed to support its own upgrade—several previous examples described packages that look ahead and control the precise method of installation under the direction of the administrator. You can design the request script to support direct upgrade of a package as well. If the administrator chooses to have one package install so as to completely replace another, leaving no residual obsolete files, the package scripts can do this.

The request script and postinstall script in this example provide a simple upgradable package. The request script communicates with the administrator and then sets up a simple file in the /tmp directory to remove the old package instance. (Although the request script creates a file (which is forbidden), it is okay because everyone has access to /tmp).

The postinstall script then executes the shell script in /tmp, which executes the necessary pkgrm command against the old package and then deletes itself.

This example illustrates a basic upgrade. It is less than fifty lines of code including some fairly long messages. It could be expanded to backout the upgrade or make other major transformations to the package as required by the designer.

The design of the user interface for an upgrade option must be absolutely sure that the administrator is fully aware of the process and has actively requested upgrade rather than parallel installation. There is nothing wrong with performing a well understood complex operation like upgrade as long as the user interface makes the operation clear.

The request Script

# request script
control an upgrade installation
 
PATH=/usr/sadm/bin:$PATH
UPGR_SCRIPT=/tmp/upgr.$PKGINST
 
UPGRADE_MSG="Do you want to upgrade the installed version ?"
 
UPGRADE_HLP="If upgrade is desired, the existing version of the \
	package will be replaced by this version. If it is not \
	desired, this new version will be installed into a different \
	base directory and both versions will be usable."
 
UPGRADE_NOTICE="Conflict approval questions may be displayed. The \
	listed files are the ones that will be upgraded. Please \
	answer \"y\" to these questions if they are presented."
 
pkginfo -v 1.0 -q SUNWstuf.\*
 
if [ $? -eq 0 ]; then
	  # See if upgrade is desired here
	  response=`ckyorn -p "$UPGRADE_MSG" -h "$UPGRADE_HLP"`
	  if [ $response = "y" ]; then
		    OldPkg=`pkginfo -v 1.0 -x SUNWstuf.\* | nawk ' \
		    /SUNW/{print $1} '`
		    # Initiate upgrade
		    echo "PATH=/usr/sadm/bin:$PATH" > $UPGR_SCRIPT
		    echo "sleep 3" >> $UPGR_SCRIPT
		    echo "echo Now removing old instance of $PKG" >> \
		    $UPGR_SCRIPT
		    if [ ${PKG_INSTALL_ROOT} ]; then
			      echo "pkgrm -n -R $PKG_INSTALL_ROOT $OldPkg" >> \
			      $UPGR_SCRIPT
		    else
			      echo "pkgrm -n $OldPkg" >> $UPGR_SCRIPT
		    fi
		    echo "rm $UPGR_SCRIPT" >> $UPGR_SCRIPT
		    echo "exit $?" >> $UPGR_SCRIPT
 
		    # Get the original package's base directory
		    OldBD=`pkgparam $OldPkg BASEDIR`
		    echo "BASEDIR=$OldBD" > $1
		    puttext -l 5 "$UPGRADE_NOTICE"
	   else
		     if [ -f $UPGR_SCRIPT ]; then
			       rm -r $UPGR_SCRIPT
		     fi
	   fi
fi
 
exit 0

The postinstall Script

# postinstall
to execute a simple upgrade
 
PATH=/usr/sadm/bin:$PATH
UPGR_SCRIPT=/tmp/upgr.$PKGINST
 
if [ -f $UPGR_SCRIPT ]; then
	  sh $UPGR_SCRIPT &
fi
 
exit 0