HardenedBSD/usr.sbin/mergemaster/mergemaster.sh
Doug Barton 6f8d4c2ffc * Reduce diffs to RELENG_4 by specifying a full path to sysctl
* Adjust a little whitespace
* Make the distrib-dirs/mtree on DESTDIR conditional on user
  actually specifying a DESTDIR. This seemed like a safe
  way to get the right directories and permissions in the
  installed tree since 'make installworld' does the same
  thing, but in practice too many people have custom hacks
  that we should leave unmolested. Still need to find a way
  to deal with 'install -d' and permissions on nonexistent
  directories in the middle of the path, but this is at
  least no worse that it was before.

PR:		bin/22661
2000-11-09 00:19:21 +00:00

819 lines
22 KiB
Bash
Executable File

#!/bin/sh
# mergemaster
# Compare files created by /usr/src/etc/Makefile (or the directory
# the user specifies) with the currently installed copies.
# Copyright 1998-2000 Douglas Barton
# Doug@gorean.org
# $FreeBSD$
PATH=/bin:/usr/bin:/usr/sbin
display_usage () {
VERSION_NUMBER=`grep "[$]FreeBSD:" $0 | cut -d ' ' -f 4`
echo "mergemaster version ${VERSION_NUMBER}"
echo 'Usage: mergemaster [-scrvahi] [-m /path]'
echo ' [-t /path] [-d] [-u N] [-w N] [-D /path]'
echo "Options:"
echo " -s Strict comparison (diff every pair of files)"
echo " -c Use context diff instead of unified diff"
echo " -r Re-run on a previously cleaned directory (skip temproot creation)"
echo " -v Be more verbose about the process, include additional checks"
echo " -a Leave all files that differ to merge by hand"
echo " -h Display more complete help"
echo ' -i Automatically install files that do not exist in destination directory'
echo " -m /path/directory Specify location of source to do the make in"
echo " -t /path/directory Specify temp root directory"
echo " -d Add date and time to directory name (e.g., /var/tmp/temproot.`date +%m%d.%H.%M`)"
echo " -u N Specify a numeric umask"
echo " -w N Specify a screen width in columns to sdiff"
echo ' -D /path/directory Specify the destination directory to install files to'
echo ''
}
display_help () {
echo "* To specify a directory other than /var/tmp/temproot for the"
echo " temporary root environment, use -t /path/to/temp/root"
echo "* The -w option takes a number as an argument for the column width"
echo " of the screen. The default is 80."
echo '* The -a option causes mergemaster to run without prompting.'
}
# Loop allowing the user to use sdiff to merge files and display the merged
# file.
merge_loop () {
case "${VERBOSE}" in
'') ;;
*)
echo " *** Type h at the sdiff prompt (%) to get usage help"
;;
esac
echo ''
MERGE_AGAIN=yes
while [ "${MERGE_AGAIN}" = "yes" ]; do
# Prime file.merged so we don't blat the owner/group id's
cp -p "${COMPFILE}" "${COMPFILE}.merged"
sdiff -o "${COMPFILE}.merged" --text --suppress-common-lines \
--width=${SCREEN_WIDTH:-80} "${DESTDIR}${COMPFILE#.}" "${COMPFILE}"
INSTALL_MERGED=V
while [ "${INSTALL_MERGED}" = "v" -o "${INSTALL_MERGED}" = "V" ]; do
echo ''
echo " Use 'i' to install merged file"
echo " Use 'r' to re-do the merge"
echo " Use 'v' to view the merged file"
echo " Default is to leave the temporary file to deal with by hand"
echo ''
echo -n " *** How should I deal with the merged file? [Leave it for later] "
read INSTALL_MERGED
case "${INSTALL_MERGED}" in
[iI])
mv "${COMPFILE}.merged" "${COMPFILE}"
echo ''
if mm_install "${COMPFILE}"; then
echo " *** Merged version of ${COMPFILE} installed successfully"
else
echo " *** Problem installing ${COMPFILE}, it will remain to merge by hand later"
fi
unset MERGE_AGAIN
;;
[rR])
rm "${COMPFILE}.merged"
;;
[vV])
${PAGER} "${COMPFILE}.merged"
;;
'')
echo " *** ${COMPFILE} will remain for your consideration"
unset MERGE_AGAIN
;;
*)
echo "invalid choice: ${INSTALL_MERGED}"
INSTALL_MERGED=V
;;
esac
done
done
}
# Loop showing user differences between files, allow merge, skip or install
# options
diff_loop () {
HANDLE_COMPFILE=v
while [ "${HANDLE_COMPFILE}" = "v" -o "${HANDLE_COMPFILE}" = "V" -o "${HANDLE_COMPFILE}" = "NOT V" ]; do
if [ -f "${DESTDIR}${COMPFILE#.}" -a -f "${COMPFILE}" ]; then
if [ "${HANDLE_COMPFILE}" = "v" -o "${HANDLE_COMPFILE}" = "V" ]; then
(
echo ''
echo " *** Displaying differences between ${COMPFILE} and installed version:"
echo ''
diff "${DIFF_FLAG}" "${DESTDIR}${COMPFILE#.}" "${COMPFILE}"
) | ${PAGER}
echo ''
fi
else
echo ''
echo " *** There is no installed version of ${COMPFILE}"
case "${AUTO_INSTALL}" in
[Yy][Ee][Ss])
echo ''
if mm_install "${COMPFILE}"; then
echo " *** ${COMPFILE} installed successfully"
echo ''
# Make the list print one file per line
AUTO_INSTALLED_FILES="${AUTO_INSTALLED_FILES} ${DESTDIR}${COMPFILE#.}
"
else
echo " *** Problem installing ${COMPFILE}, it will remain to merge by hand"
fi
return
;;
*)
NO_INSTALLED=yes
;;
esac
fi
echo " Use 'd' to delete the temporary ${COMPFILE}"
echo " Use 'i' to install the temporary ${COMPFILE}"
case "${NO_INSTALLED}" in
'')
echo " Use 'm' to merge the old and new versions"
echo " Use 'v' to view to differences between the old and new versions again"
;;
esac
echo ''
echo " Default is to leave the temporary file to deal with by hand"
echo ''
echo -n "How should I deal with this? [Leave it for later] "
read HANDLE_COMPFILE
case "${HANDLE_COMPFILE}" in
[dD])
rm "${COMPFILE}"
echo ''
echo " *** Deleting ${COMPFILE}"
;;
[iI])
echo ''
if mm_install "${COMPFILE}"; then
echo " *** ${COMPFILE} installed successfully"
else
echo " *** Problem installing ${COMPFILE}, it will remain to merge by hand"
fi
;;
[mM])
case "${NO_INSTALLED}" in
'')
# interact with user to merge files
merge_loop
;;
*)
echo ''
echo " *** There is no installed version of ${COMPFILE}"
echo ''
HANDLE_COMPFILE="NOT V"
;;
esac # End of "No installed version of file but user selected merge" test
;;
[vV])
continue
;;
'')
echo ''
echo " *** ${COMPFILE} will remain for your consideration"
;;
*)
# invalid choice, show menu again.
echo "invalid choice: ${HANDLE_COMPFILE}"
echo ''
HANDLE_COMPFILE="NOT V"
continue
;;
esac # End of "How to handle files that are different"
done
unset NO_INSTALLED
echo ''
case "${VERBOSE}" in
'') ;;
*)
sleep 3
;;
esac
}
# Set the default path for the temporary root environment
#
TEMPROOT='/var/tmp/temproot'
# Read .mergemasterrc before command line so CLI can override
#
if [ -r "$HOME/.mergemasterrc" ]; then
. "$HOME/.mergemasterrc"
fi
# Check the command line options
#
while getopts ":ascrvhim:t:du:w:D:" COMMAND_LINE_ARGUMENT ; do
case "${COMMAND_LINE_ARGUMENT}" in
s)
STRICT=yes
;;
c)
DIFF_FLAG='-c'
;;
r)
RERUN=yes
;;
v)
case "${AUTO_RUN}" in
'') VERBOSE=yes ;;
esac
;;
a)
AUTO_RUN=yes
unset VERBOSE
;;
h)
display_usage
display_help
exit 0
;;
i)
AUTO_INSTALL=yes
;;
m)
SOURCEDIR=${OPTARG}
;;
t)
TEMPROOT=${OPTARG}
;;
d)
TEMPROOT=${TEMPROOT}.`date +%m%d.%H.%M`
;;
u)
NEW_UMASK=${OPTARG}
;;
w)
SCREEN_WIDTH=${OPTARG}
;;
D)
DESTDIR=${OPTARG}
;;
*)
display_usage
exit 1
;;
esac
done
echo ''
# If the user has a pager defined, make sure we can run it
#
case "${DONT_CHECK_PAGER}" in
'')
while ! type "${PAGER%% *}" >/dev/null && [ -n "${PAGER}" ]; do
echo " *** Your PAGER environment variable specifies '${PAGER}', but"
echo " due to the limited PATH that I use for security reasons,"
echo " I cannot execute it. So, what would you like to do?"
echo ''
echo " Use 'e' to exit mergemaster and fix your PAGER variable"
if [ -x /usr/bin/less -o -x /usr/local/bin/less ]; then
echo " Use 'l' to set PAGER to 'less' for this run"
fi
echo " Use 'm' to use plain old 'more' as your PAGER for this run"
echo ''
echo " Default is to use plain old 'more' "
echo ''
echo -n "What should I do? [Use 'more'] "
read FIXPAGER
case "${FIXPAGER}" in
[eE])
exit 0
;;
[lL])
if [ -x /usr/bin/less ]; then
PAGER=/usr/bin/less
elif [ -x /usr/local/bin/less ]; then
PAGER=/usr/local/bin/less
else
echo ''
echo " *** Fatal Error:"
echo " You asked to use 'less' as your pager, but I can't"
echo " find it in /usr/bin or /usr/local/bin"
exit 1
fi
;;
[mM]|'')
PAGER=more
;;
*)
echo ''
echo "invalid choice: ${FIXPAGER}"
esac
echo ''
done
;;
esac
# If user has a pager defined, or got assigned one above, use it.
# If not, use more.
#
PAGER=${PAGER:-more}
if [ -n "${VERBOSE}" -a ! "${PAGER}" = "more" ]; then
echo " *** You have ${PAGER} defined as your pager so we will use that"
echo ''
sleep 3
fi
# Assign the diff flag once so we will not have to keep testing it
#
DIFF_FLAG=${DIFF_FLAG:--u}
# Assign the source directory
#
SOURCEDIR=${SOURCEDIR:-/usr/src/etc}
case "${RERUN}" in
'')
# Set up the loop to test for the existence of the
# temp root directory.
#
TEST_TEMP_ROOT=yes
while [ "${TEST_TEMP_ROOT}" = "yes" ]; do
if [ -d "${TEMPROOT}" ]; then
echo "*** The directory specified for the temporary root environment,"
echo " ${TEMPROOT}, exists. This can be a security risk if untrusted"
echo " users have access to the system."
echo ''
case "${AUTO_RUN}" in
'')
echo " Use 'd' to delete the old ${TEMPROOT} and continue"
echo " Use 't' to select a new temporary root directory"
echo " Use 'e' to exit mergemaster"
echo ''
echo " Default is to use ${TEMPROOT} as is"
echo ''
echo -n "How should I deal with this? [Use the existing ${TEMPROOT}] "
read DELORNOT
case "${DELORNOT}" in
[dD])
echo ''
echo " *** Deleting the old ${TEMPROOT}"
echo ''
rm -rf "${TEMPROOT}"
unset TEST_TEMP_ROOT
;;
[tT])
echo " *** Enter new directory name for temporary root environment"
read TEMPROOT
;;
[eE])
exit 0
;;
'')
echo ''
echo " *** Leaving ${TEMPROOT} intact"
echo ''
unset TEST_TEMP_ROOT
;;
*)
echo ''
echo "invalid choice: ${DELORNOT}"
echo ''
;;
esac
;;
*)
# If this is an auto-run, try a hopefully safe alternative then re-test anyway
TEMPROOT=/var/tmp/temproot.`date +%m%d.%H.%M.%S`
;;
esac
else
unset TEST_TEMP_ROOT
fi
done
echo "*** Creating the temporary root environment in ${TEMPROOT}"
if mkdir -p "${TEMPROOT}"; then
echo " *** ${TEMPROOT} ready for use"
fi
if [ ! -d "${TEMPROOT}" ]; then
echo ''
echo " *** FATAL ERROR: Cannot create ${TEMPROOT}"
echo ''
exit 1
fi
echo " *** Creating and populating directory structure in ${TEMPROOT}"
echo ''
case "${VERBOSE}" in
'') ;;
*)
echo " *** Press [Enter] or [Return] key to continue"
read ANY_KEY
unset ANY_KEY
;;
esac
{ cd ${SOURCEDIR} &&
case "${DESTDIR}" in
'') ;;
*)
make DESTDIR=${DESTDIR} distrib-dirs
;;
esac
make DESTDIR=${TEMPROOT} distrib-dirs &&
make DESTDIR=${TEMPROOT} -DNO_MAKEDEV distribution;} ||
{ echo '';
echo " *** FATAL ERROR: Cannot 'cd' to ${SOURCEDIR} and install files to the";
echo " temproot environment";
echo '';
exit 1;}
# Doing the inventory and removing files that we don't want to compare only makes
# sense if we are not doing a rerun, since we have no way of knowing what happened
# to the files during previous incarnations.
case "${VERBOSE}" in
'') ;;
*)
echo ''
echo ' *** The following files exist only in the installed version of'
echo " ${DESTDIR}/etc. In the vast majority of cases these files"
echo ' are necessary parts of the system and should not be deleted.'
echo ' However because these files are not updated by this process you'
echo ' might want to verify their status before rebooting your system.'
echo ''
echo ' *** Press [Enter] or [Return] key to continue'
read ANY_KEY
unset ANY_KEY
diff -qr ${DESTDIR}/etc ${TEMPROOT}/etc | grep "^Only in /etc" | ${PAGER}
echo ''
echo ' *** Press [Enter] or [Return] key to continue'
read ANY_KEY
unset ANY_KEY
;;
esac
# We really don't want to have to deal with these files, since
# master.passwd is the real file that should be compared, then
# the user should run pwd_mkdb if necessary.
#
rm ${TEMPROOT}/etc/spwd.db ${TEMPROOT}/etc/passwd ${TEMPROOT}/etc/pwd.db
# Avoid comparing the motd if the user specifies it in .mergemasterrc
case "${IGNORE_MOTD}" in
'') ;;
*) rm ${TEMPROOT}/etc/motd
;;
esac
# Avoid trying to update MAKEDEV if /dev is on a devfs
if /sbin/sysctl vfs.devfs.generation > /dev/null 2>&1 ; then
rm ${TEMPROOT}/dev/MAKEDEV ${TEMPROOT}/dev/MAKEDEV.local
fi
;; # End of the "RERUN" test
esac
# Get ready to start comparing files
# Check umask if not specified on the command line,
# and we are not doing an autorun
#
if [ -z "${NEW_UMASK}" -a -z "${AUTO_RUN}" ]; then
USER_UMASK=`umask`
case "${USER_UMASK}" in
0022) ;;
*)
echo ''
echo " *** Your umask is currently set to ${USER_UMASK}. By default, this script"
echo " installs all files with the same user, group and modes that"
echo " they are created with by ${SOURCEDIR}/Makefile, compared to"
echo " a umask of 022. This umask allows world read permission when"
echo " the file's default permissions have it."
echo " No world permissions can sometimes cause problems. A umask of"
echo " 022 will restore the default behavior, but is not mandatory."
echo " /etc/master.passwd is a special case. Its file permissions"
echo " will be 600 (rw-------) if installed."
echo ''
echo -n "What umask should I use? [${USER_UMASK}] "
read NEW_UMASK
NEW_UMASK="${NEW_UMASK:-$USER_UMASK}"
;;
esac
echo ''
fi
CONFIRMED_UMASK=${NEW_UMASK:-0022}
# Warn users who still have ${DESTDIR}/etc/sysconfig
#
if [ -e "${DESTDIR}/etc/sysconfig" ]; then
echo ''
echo " *** There is a sysconfig file on this system in ${DESTDIR}/etc/."
echo ''
echo ' Starting with FreeBSD version 2.2.2 those settings moved from'
echo ' /etc/sysconfig to /etc/rc.conf. If you are upgrading an older'
echo ' system make sure that you transfer your settings by hand from'
echo ' sysconfig to rc.conf and install the rc.conf file. If you'
echo ' have already made this transition, you should consider'
echo ' renaming or deleting the sysconfig file.'
echo ''
case "${AUTO_RUN}" in
'')
echo -n "Continue with the merge process? [yes] "
read CONT_OR_NOT
case "${CONT_OR_NOT}" in
[nN]*)
exit 0
;;
*)
echo " *** Continuing"
echo ''
;;
esac
;;
*) ;;
esac
fi
# Use the umask/mode information to install the files
# Create directories as needed
#
mm_install () {
local INSTALL_DIR
INSTALL_DIR=${1#.}
INSTALL_DIR=${INSTALL_DIR%/*}
case "${INSTALL_DIR}" in
'')
INSTALL_DIR=/
;;
esac
if [ -n "${DESTDIR}${INSTALL_DIR}" -a ! -d "${DESTDIR}${INSTALL_DIR}" ]; then
DIR_MODE=`perl -e 'printf "%04o\n", (((stat("$ARGV[0]"))[2] & 07777) &~ oct("$ARGV[1]"))' "${TEMPROOT}/${INSTALL_DIR}" "${CONFIRMED_UMASK}"`
install -d -o root -g wheel -m "${DIR_MODE}" "${DESTDIR}${INSTALL_DIR}"
fi
FILE_MODE=`perl -e 'printf "%04o\n", (((stat("$ARGV[0]"))[2] & 07777) &~ oct("$ARGV[1]"))' "${1}" "${CONFIRMED_UMASK}"`
if [ ! -x "${1}" ]; then
case "${1#.}" in
/etc/mail/aliases)
NEED_NEWALIASES=yes
;;
/etc/login.conf)
NEED_CAP_MKDB=yes
;;
/etc/master.passwd)
install -m 600 "${1}" "${DESTDIR}${INSTALL_DIR}"
NEED_PWD_MKDB=yes
DONT_INSTALL=yes
;;
/.cshrc | /.profile)
case "${LINK_EXPLAINED}" in
'')
echo " *** Historically BSD derived systems have had a"
echo " hard link from /.cshrc and /.profile to"
echo " their namesakes in /root. Please indicate"
echo " your preference below for bringing your"
echo " installed files up to date."
echo ''
LINK_EXPLAINED=yes
;;
esac
echo " Use 'd' to delete the temporary ${COMPFILE}"
echo " Use 'l' to delete the existing ${DESTDIR}${COMPFILE#.} and create the link"
echo ''
echo " Default is to leave the temporary file to deal with by hand"
echo ''
echo -n " How should I handle ${COMPFILE}? [Leave it to install later] "
read HANDLE_LINK
case "${HANDLE_LINK}" in
[dD]*)
rm "${COMPFILE}"
echo ''
echo " *** Deleting ${COMPFILE}"
;;
[lL]*)
echo ''
rm -f "${DESTDIR}${COMPFILE#.}"
if ln "${DESTDIR}/root/${COMPFILE##*/}" "${DESTDIR}${COMPFILE#.}"; then
echo " *** Link from ${DESTDIR}${COMPFILE#.} to ${DESTDIR}/root/${COMPFILE##*/} installed successfully"
rm "${COMPFILE}"
else
echo " *** Error linking ${DESTDIR}${COMPFILE#.} to ${DESTDIR}/root/${COMPFILE##*/}, ${COMPFILE} will remain to install by hand"
fi
;;
*)
echo " *** ${COMPFILE} will remain for your consideration"
;;
esac
DONT_INSTALL=yes
;;
esac
case "${DONT_INSTALL}" in
'')
install -m "${FILE_MODE}" "${1}" "${DESTDIR}${INSTALL_DIR}"
;;
*)
unset DONT_INSTALL
;;
esac
else
case "${1#.}" in
/dev/MAKEDEV)
NEED_MAKEDEV=yes
;;
esac
install -m "${FILE_MODE}" "${1}" "${DESTDIR}${INSTALL_DIR}"
fi
return $?
}
echo ''
echo "*** Beginning comparison"
echo ''
cd "${TEMPROOT}"
if [ -r "${MM_PRE_COMPARE_SCRIPT}" ]; then
. "${MM_PRE_COMPARE_SCRIPT}"
fi
# Using -size +0 avoids uselessly checking the empty log files created
# by ${SOURCEDIR}/Makefile and the device entries in ./dev, but does
# check the scripts in ./dev, as we'd like (assuming no devfs of course).
#
for COMPFILE in `find . -type f -size +0`; do
# First, check to see if the file exists in DESTDIR. If not, the
# diff_loop function knows how to handle it.
#
if [ ! -e "${DESTDIR}${COMPFILE#.}" ]; then
diff_loop
continue
fi
case "${STRICT}" in
'' | [Nn][Oo])
# Compare CVS $Id's first so if the file hasn't been modified
# local changes will be ignored.
# If the files have the same $Id, delete the one in temproot so the
# user will have less to wade through if files are left to merge by hand.
#
# Reduce complexity and improve portability by using ident
#
CVSID1=`ident ${DESTDIR}${COMPFILE#.} 2>&1`
CVSID1="${CVSID1#${DESTDIR}}"
CVSID2=`ident ${COMPFILE} 2>&1`
case "${CVSID2}" in
*'no id keywords'*)
;;
."${CVSID1}")
echo " *** Temp ${COMPFILE} and installed have the same CVS Id, deleting"
rm "${COMPFILE}"
;;
esac
;;
esac
# If the file is still here either because the $Ids are different, the
# file doesn't have an $Id, or we're using STRICT mode; look at the diff.
#
if [ -f "${COMPFILE}" ]; then
# Do an absolute diff first to see if the files are actually different.
# If they're not different, delete the one in temproot.
#
if diff -q "${DESTDIR}${COMPFILE#.}" "${COMPFILE}" > /dev/null 2>&1; then
echo " *** Temp ${COMPFILE} and installed are the same, deleting"
rm "${COMPFILE}"
else
# Ok, the files are different, so show the user where they differ. Use user's
# choice of diff methods; and user's pager if they have one. Use more if not.
# Use unified diffs by default. Context diffs give me a headache. :)
#
case "${AUTO_RUN}" in
'')
# prompt user to install/delete/merge changes
diff_loop
;;
*)
# If this is an auto run, make it official
echo " *** ${COMPFILE} will remain for your consideration"
;;
esac # Auto run test
fi # Yes, the files are different
fi # Yes, the file still remains to be checked
done # This is for the do way up there at the beginning of the comparison
echo ''
echo "*** Comparison complete"
echo ''
TEST_FOR_FILES=`find ${TEMPROOT} -type f -size +0 2>/dev/null`
if [ -n "${TEST_FOR_FILES}" ]; then
echo "*** Files that remain for you to merge by hand:"
find "${TEMPROOT}" -type f -size +0
fi
case "${AUTO_RUN}" in
'')
echo ''
echo -n "Do you wish to delete what is left of ${TEMPROOT}? [no] "
read DEL_TEMPROOT
case "${DEL_TEMPROOT}" in
[yY]*)
if rm -rf "${TEMPROOT}"; then
echo " *** ${TEMPROOT} has been deleted"
else
echo " *** Unable to delete ${TEMPROOT}"
fi
;;
*)
echo " *** ${TEMPROOT} will remain"
;;
esac
;;
*) ;;
esac
case "${AUTO_INSTALLED_FILES}" in
'') ;;
*)
(
echo ''
echo '*** You chose the automatic install option for files that did not exist'
echo ' on your system. The following files were installed for you:'
echo "${AUTO_INSTALLED_FILES}"
) | ${PAGER}
;;
esac
case "${NEED_MAKEDEV}" in
'') ;;
*)
echo ''
echo "*** You installed a new /dev/MAKEDEV script, so make sure that you run"
echo " 'cd /dev && /bin/sh MAKEDEV all' to rebuild your devices"
;;
esac
case "${NEED_NEWALIASES}" in
'') ;;
*)
echo ''
echo "*** You installed a new aliases file, so make sure that you run"
echo " 'newaliases' to rebuild your aliases database"
;;
esac
case "${NEED_CAP_MKDB}" in
'') ;;
*)
echo ''
echo "*** You installed a login.conf file, so make sure that you run"
echo " 'cap_mkdb /etc/login.conf' to rebuild your login.conf database"
;;
esac
case "${NEED_PWD_MKDB}" in
'') ;;
*)
echo ''
echo "*** You installed a new master.passwd file, so make sure that you run"
echo " 'pwd_mkdb -p /etc/master.passwd' to rebuild your password files"
;;
esac
echo ''
if [ -r "${MM_EXIT_SCRIPT}" ]; then
. "${MM_EXIT_SCRIPT}"
fi
exit 0