_NetBSD-pkgdb: Add migration script

This script can check if all is consistent, fix consistency issues
(without migrating), or actually migrate.

I am running out of systems to test migration on.   This script should
be, for now, viewed with suspicion, and run in fix or migrate mode
only on systems with good backups, or for which you genuinely don't
care if you have to start over with pkgsrc.

1 files changed, 327 insertions, 0 deletions

diff --git a/_NetBSD-pkgdb b/_NetBSD-pkgdb
new file mode 100755
index 00000000000..03fc5b54e2e
--- /dev/null
+++ b/_NetBSD-pkgdb
@@ -0,0 +1,327 @@
+#!/bin/sh
+# $NetBSD: _NetBSD-pkgdb,v 1.1 2020/12/28 01:18:27 gdt Exp $
+# Copyright The NetBSD Foundation 2020
+
+# This script is for NetBSD only.
+
+# This script is intended to help with the process of migration of
+# PKG_DBDIR from /var/db/pkg to /usr/pkg/pkgdb on NetBSD.  It can:
+#
+#   "check" the system, changing nothing
+#
+#   "fix" the system, leaving PKG_DBDIR as is and setting config files
+#   to point to it.  Thus, one can easily postpone migration.
+#
+#   "migrate" the system, moving the contents of PKG_DBDIR to the new
+#   location, and then setting pointers.
+#
+# In all cases, the script attempts to check assumptions it makes, and
+# avoid trouble if those assumptions are not true.
+
+# Note that PKG_DBDIR can be set in multiple places:
+#   /etc/pkg_install.conf (base tools)
+#   /usr/pkg/etc/pkg_install.conf (pkg tools)
+#   /etc/mk.conf (variable when buidling)
+#   /usr/pkgsrc/mk/ (default value of variable)
+
+# This script takes the position that the PKG_DBDIR should be
+# explicitly configured in pkg_install.conf in all cases, even if this
+# is provably not necessary.  The theory is that a bit of explicit
+# config is much less work than mysterious debugging.  If you don't
+# like this, you are welcome to undo it, only use "check", or do the
+# migration (or not) by hand.
+
+# This script is aimed at the common case where the database was in
+# /var/db/pkg and is moving to /usr/pkg/pkgdb, and sources are in
+# /usr/pkgsrc (or a place that /usr/pkgsrc is symlinked to).
+
+# This script should work to fix/migrate even on systems with older
+# pkgsrc, e.g. if one wanted to stay on 2020Q3 on a system where the
+# base system tools were updated.  "Fix" will set variables so
+# everything should work correctly.
+
+# The script is designed to do incremental fixes, so if you migrate by
+# hand but do not patch up the refcount directory, or set variables,
+# it should (NB: This is UNTESTED!) do those steps when run.
+
+# The script is intentionally written to be easy to understand (as
+# long as one is comfortable with shell functions), rather than
+# compact, avoid repeated code, or elegant.
+
+# This script assumes:
+#   NetBSD 8 or newer
+#   pkgsrc after about 2020-12-20 (including 2020Q4)
+#   pkgsrc PREFIX as /usr/pkg
+#   old PKG_DBDIR as /var/db/pkg
+#   new/future PKG_DBDIR as /usr/pkg
+#   no symlinks in old or new PKG_DBDIR location
+#   base pkg_install may be old, or may be after the 2020-12 commit/pullups
+#   pkgsrc sources, if they exist, are in /usr/pkgsrc (perhaps a symlink)
+
+# Set pathnames.  Do not expect to set these differently without
+# significant testing and thought.
+OLDDB=/var/db/pkg
+NEWDB=/usr/pkg/pkgdb
+CONF_BASE=/etc/pkg_install.conf
+CONF_PKG=/usr/pkg/etc/pkg_install.conf
+PKGSRC=/usr/pkgsrc
+
+# Shell functions to print messages of varying severity.  (We choose
+# to avoid fancy formatting entirely in this script.)
+msg () {
+    echo "$*" >&2
+}
+
+warn () {
+    echo "WARNING: $*" >&2
+}
+
+fatal () {
+    echo "FATAL: $*" >&2
+    exit 1
+}
+
+usage () {
+    msg "_NetBSD-pkgdb: Usage:"
+    msg "    check     Check pkgdb status and explain it."
+    msg "    fix       Point config files at pkgdb location (don't move it)."
+    msg "    migrate   Check if migration can be done automatically, and if so do it."
+    exit 1
+}
+
+# Count problems.  (Be sure not to use subshells when calling this.)
+problems=0
+problem_pp () {
+    problems=`expr $problems + 1`
+
+}
+problem_count () {
+    echo $problems
+}
+
+dir_exists () {
+    if [ ! -h "$1" -a -d "$1" ]; then
+	echo true
+    else
+	echo false
+    fi
+}
+
+# require_match string bool1 bool2
+require_match () {
+    if [ "$2" != "$3" ]; then
+	fatal "mismatch $1"
+	problem_pp
+    fi
+}
+
+# Read pkg_install.conf PKG_DBDIR.  One arg: config file
+get_pkg_install_conf_DBDIR () {
+    CONF=$1
+    if [ "${CONF}" = "" ]; then
+	fatal "missing argument"
+	# dead code, left in case error is removed
+	echo ""
+    elif [ ! -f ${CONF} ]; then
+	warn "${CONF} does not exist"
+	echo ""
+    else
+	line=`egrep "^PKG_DBDIR.*=" ${CONF}`
+	if [ "$line" = "" ]; then
+	    warn "${CONF} does not set PKG_DBDIR"
+	    echo ""
+	else
+	    value=`echo $line | awk -F= '{print $2}'`
+	    echo $value
+	fi
+    fi
+}
+
+# Ensure prerequisites.
+do_prereq () {
+    if [ `uname` != "NetBSD" ];then
+	fatal "OS is not NetBSD"
+    fi
+
+    # Check a subdir, in case /usr/pkg is a symlink.
+    if [ ! -d /usr/pkg/bin ]; then
+	fatal "/usr/pkg/bin is not a directory"
+    fi
+}
+
+# Check and maybe fix or migrate, depending on if fix=true or
+# migrate=true.   migrate=true and fix=false is not allowed.
+do_steps () {
+    ## STEP 0: Check if it is ok to operate at all.
+    do_prereq
+
+    ## STEP 1: Sanity check database and figure out where it is.
+    # See if old or new exists, and check that they are in pairs.
+    OLD_DB1=`dir_exists ${OLDDB}`
+    OLD_DB2=`dir_exists ${OLDDB}.refcount`
+    require_match "$OLDDB directory pair" $OLD_DB1 $OLD_DB2
+    NEW_DB1=`dir_exists ${NEWDB}`
+    NEW_DB2=`dir_exists ${NEWDB}.refcount`
+    require_match "$NEWDB directory pair" $NEW_DB1 $NEW_DB2
+
+    # Check that we have one PKG_DBDIR, not zero and not two
+    if [ "$OLD_DB1" = false -a "$NEW_DB1" = false ]; then
+	fatal "No PKG_DBDIR found"
+	problem_pp
+    fi
+    if [ "$OLD_DB1" = true -a "$NEW_DB1" = true ]; then
+	fatal "TWO copies of PKG_DBDIR found"
+	problem_pp
+    fi
+
+    # Set a variable to the DBDIR we should be using, and the one we aren't.
+    if [ "$OLD_DB1" = true ]; then
+	PKG_DBDIR=$OLDDB
+	PKG_DBDIR_NOT=$NEWDB
+    elif [ "$NEW_DB1" = true ]; then
+	PKG_DBDIR=$NEWDB
+	PKG_DBDIR_NOT=$OLDDB
+    else
+	fatal "LOGIC ERROR IN SCRIPT 001"
+	exit 1
+    fi
+    unset OLD_DB1
+    unset OLD_DB2
+    unset NEW_DB1
+    unset OLD_DB2
+    echo "Found PKG_DBDIR as $PKG_DBDIR."
+
+    ## Step 2a: check migrate/fix prereqs
+    if [ "$fix" = true ]; then
+	warn "THIS SCRIPT IS NOT YET ADEQUATELY TESTED."
+	warn "Hit ^C NOW if you do not have a good backup."
+	warn "Proceeding in 10 seconds..."
+	sleep 10
+
+	if [ `id -u` != 0 ]; then
+	    fatal "Not root: will not be able to fix or migrate"
+	fi
+    fi
+
+    ## Step 2: migrate if requested
+    if [ "$migrate" = true ]; then
+	if [ "$fix" != true ]; then
+	    fatal "LOGIC ERROR IN SCRIPT 002"
+	fi
+	
+	if [ "$PKG_DBDIR" = "${NEWDB}" ]; then
+	    warn "migrate requested when already done"
+	    # This is not really an error.
+	else
+	    msg "Doing migration..."
+	    msg "NB: refcount will have many fixups; this is normal."
+
+	    # Actual migration is easy.
+	    mv $OLDDB $NEWDB
+	    mv $OLDDB.refcount $NEWDB.refcount
+
+	    # Change our tracking variables so that later fixups do
+	    # the right thing.
+	    PKG_DBDIR=$NEWDB
+	    PKG_DBDIR_NOT=$OLDDB
+
+	    msg "Migration done, except for refcount fixups."
+	fi
+    fi
+
+    ## Step 3: Check/fix refcount
+    if [ "$fix" = true ]; then
+	# Check all files, even though only some have paths.
+	find ${PKG_DBDIR}.refcount -type f | while read file; do
+	    if egrep $PKG_DBDIR_NOT $file > /dev/null; then
+		echo WRONG PATH $file
+		sed -i -e "s,${PKG_DBDIR_NOT},${PKG_DBDIR}," $file
+		problem_pp
+	    fi
+	done
+    fi
+    
+    ## Step 4: Check PKG_DBDIR variables and fix if requested.
+    # Check that both pkg_install configs point to the actual PKG_DBDIR.
+    conf_base_DBDIR=`get_pkg_install_conf_DBDIR $CONF_BASE`
+    if [ "$conf_base_DBDIR" != "${PKG_DBDIR}" ]; then
+	warn "$CONF_BASE does not set PKG_DBDIR to ${PKG_DBDIR}"
+	if [ "$fix" = true ]; then
+	    [ -f ${CONF_BASE} ] && cp -p ${CONF_BASE} ${CONF_BASE}.pre-migration
+	    sed -i -e '/^PKG_DBDIR=/d' ${CONF_BASE}
+	    echo "PKG_DBDIR=${PKG_DBDIR}" >> ${CONF_BASE}
+	fi
+	problem_pp
+    fi
+    conf_pkg_DBDIR=`get_pkg_install_conf_DBDIR $CONF_PKG`
+    if [ "$conf_pkg_DBDIR" != "${PKG_DBDIR}" ]; then
+	warn "$CONF_PKG does not set PKG_DBDIR to ${PKG_DBDIR}"
+	if [ "$fix" = true ]; then
+	    [ -f ${CONF_PKG} ] && cp -p ${CONF_PKG} ${CONF_PKG}.pre-migration
+	    sed -i -e '/^PKG_DBDIR=/d' ${CONF_PKG}
+	    echo "PKG_DBDIR=${PKG_DBDIR}" >> ${CONF_PKG}
+	fi
+	problem_pp
+    fi
+
+    # Check mk.conf via pkgsrc.  Really, check that the variable is
+    # set when running in an example package, because it is relatively
+    # normal to use .include and we decline to re-implement make.
+    if [ -d ${PKGSRC}/mk ]; then
+	# Avoid a subshell so problem_pp works.
+	SAVE=`pwd`
+	cd $PKGSRC
+	PKGSRC_DBDIR=`cd devel/m4 && make show-var VARNAME=PKG_DBDIR`
+	if [ "$PKGSRC_DBDIR" != "${PKG_DBDIR}" ]; then
+	    warn "$PKG_DBDIR via pkgsrc/mk does not set PKG_DBDIR to ${PKG_DBDIR}"
+	    # This may have failed for other reasons, but if so running again won't
+	    # fix it.
+	    if [ "$fix" = true ]; then
+		sed -i -e '/^PKG_DBDIR=/d' /etc/mk.conf
+		echo "PKG_DBDIR=${PKG_DBDIR}" >> /etc/mk.conf
+	    fi
+	    problem_pp
+	fi
+	cd $SAVE
+	unset SAVE
+    else
+	msg "NB: Did not find ${PKGSRC} -- did not check mk.conf"
+	msg "    If your system does not have sources, this is ok.  If it does, symlink"
+	msg "    ${PKGSRC} to the sources and rerun the check."
+    fi
+}
+    
+main() {
+    if [ "$#" != 1 ]; then
+	usage
+    fi
+    
+    case "$1" in
+	check)
+	    do_steps
+	    ;;
+	fix)
+	    fix=true;
+	    do_steps
+	    ;;
+	migrate)
+	    fix=true
+	    migrate=true;
+	    do_steps
+	    ;;
+	*)
+	    warn Unknown option $1
+	    usage
+	    ;;
+    esac
+
+    count=`problem_count`
+    if [ "$count" = 0 ]; then
+	msg "No problems found."
+    else
+	msg "TOTAL PROBLEMS FOUND: $count"
+	msg "Re-run script until there are no problems!"
+    fi
+}
+
+main $*