Attachment 825208 Details for Bug 1031243 – Script to shrink locale-archive safely on a running system

Script to shrink locale-archive safely on a running system

shrink_locale_archive.sh (text/plain), 3.74 KB, created by Andrew J. Schorr on 2013-11-17 17:02:43 UTC

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Creator: Andrew J. Schorr

Created: 2013-11-17 17:02:43 UTC

Size: 3.74 KB

patch

obsolete

>#!/bin/bash
># RcsId: $Id: shrink_locale_archive.sh,v 1.3 2013/11/17 16:55:07 schorr Exp $
>
>set -o pipefail
>erc=0
>
>fn=/usr/lib/locale/locale-archive
>
># N.B. $fn is slightly sparse.
>
>usage () {
>   echo "Usage: `basename $0` <locale name to retain, e.g. en_US.utf8>
>
>   Shrinks monster file $fn by removing all locales
>   other than the argument.
>" 1>&2
>   exit 1
>}
>
>while getopts h flag ; do
>   case $flag in
>   *) usage ;;
>   esac
>done
>shift `expr $OPTIND - 1`
>
>[ $# -ne 1 ] && usage
>keep="$1"
>
>localedef --list-archive | gawk -v "keep=$keep" '
>$0 == keep {
>   found++
>}
>
>END {
>   if (found == 1)
>      printf "Good, I found the %s locale\n", keep
>   else {
>      printf "Error: I cannot find the locale %s in the archive.\n", keep
>      exit 1
>   }
>}' || exit 1
>
>doit () {
>   echo "	$@"
>   eval "$@" || {
>      echo "Error: command [$@] failed with rc $?" 1>&2
>      exit 1
>   }
>}
>
>tmpdir=`mktemp -dt shrinkla.XXXXXXXXXX` || {
>   echo "mktemp failed"
>   exit 1
>}
>trap "rm -rf $tmpdir" 0
>trap "exit 2" 1 2 3 6 13 15
>
># note: localedef takes a --prefix arg to set the directory where this
># stuff lives.  Unfortunately, build-locale-archive does not implement
># a --prefix option.
># See https://bugzilla.redhat.com/show_bug.cgi?id=1031243
>
># If both had --prefix, we could build a completely new version off to
># the side and then install the new archive atomically.  Sigh.
>
># Note: in Fedora 19, the original file was 102M, and after shrinking,
># it was 1.6M
>
># returns 2 values: free space for non-root and free space for root
>fs_free_space () {
>   stat -f -c "%a %f %S" "$1" | awk '{printf "%.0f %.0f\n", $1*$3, $2*$3}'
>}
>
>file_size () {
>   stat -c "%b %B" "$1" | awk '{printf "%.0f\n", $1*$2}'
>}
>
>doit "ls -l $fn"
>
>fsize=`file_size $fn`
>echo "Actual disk space used by $fn is $fsize"
>
>check_space () {
>   local dir="$1"
>   set `fs_free_space $dir`
>
>   if [ "$1" -gt "$fsize" ]; then
>      echo "Good, $dir free space $1 is big enough"
>   elif [ "$2" -gt "$fsize" ]; then
>      echo -n "OK, space is a little tight in $dir, but root can use $2,
>which is big enough.  Shall I proceed? [Y] "
>      read resp
>      case "$resp" in
>      [nN]*) echo "Aborting"; exit 1 ;;
>      *) echo "OK, I will proceed." ;;
>      esac
>   else
>      echo "Error: there is not enough space in $dir to contain a copy."
>      echo "Free space available to root is $2 bytes."
>      exit 1
>   fi
>}
>
>check_space $tmpdir
>check_space `dirname $fn`
>
>nfn=${tmpdir}$fn
>doit "mkdir -p `dirname $nfn`"
># note that $fn is sparse, but cp handles this automatically
>doit "cp -p $fn $nfn"
>pfxarg="--prefix $tmpdir"
>
># N.B. from the source code, it appears that localedef --delete-from-archive
># just zeroes out a hashtable entry in the mapped archive file.
>doit "localedef --list-archive | gawk -v keep=$keep '\$0 != keep' | xargs localedef --delete-from-archive $pfxarg"
>
># there is a a race condition here where the file is missing.  I guess
># a program that starts at this time and tries to map it will fail.
>doit "mv $nfn ${nfn}.tmpl"
>doit "rm -f ${fn}.tmpl"
>doit "ln -s ${nfn}.tmpl ${fn}.tmpl"
># note that running processes may have the file mapped, so when we reomve
># the file here, we do not release the disk space.  But they should continue
># to run fine with their private copies of the file.
>doit "rm -f $fn"
>
># Builds a new archive from ${fn}.tmpl and then truncates ${fn}.tmpl
># In a better world, this would build the new archive in a temporary file
># and then install it atomically with rename.  And it should let the user
># specify a different location for the tmpl file so there would be no need to
># use a symbolic link to trick it.
>doit "build-locale-archive"
>
>doit "rm -f ${fn}.tmpl"
>doit "touch ${fn}.tmpl"
>
>echo "You may need to reboot to reclaim the space being
>held open by processes that have mapped the old (huge) version."
>
>exit $erc

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Attachments on bug 1031243: 825208