#!/bin/sh
#set -e
#
# This file understands the following apt configuration variables:
# Values here are the default.
# Create /etc/apt/apt.conf.d/02periodic file to set your preference.
#
# Dir "/";
# - RootDir for all configuration files
#
# Dir::Cache "var/cache/apt/";
# - Set apt package cache directory
#
# Dir::Cache::Archives "archives/";
# - Set package archive directory
#
# APT::Periodic::Enable "1";
# - Enable the update/upgrade script (0=disable)
#
# APT::Periodic::BackupArchiveInterval "0";
# - Backup after n-days if archive contents changed.(0=disable)
#
# APT::Periodic::BackupLevel "3";
# - Backup level.(0=disable), 1 is invalid.
#
# Dir::Cache::Backup "backup/";
# - Set periodic package backup directory
#
# APT::Archives::MaxAge "0"; (old, deprecated)
# APT::Periodic::MaxAge "0"; (new)
# - Set maximum allowed age of a cache package file. If a cache
# package file is older it is deleted (0=disable)
#
# APT::Archives::MinAge "2"; (old, deprecated)
# APT::Periodic::MinAge "2"; (new)
# - Set minimum age of a package file. If a file is younger it
# will not be deleted (0=disable). Useful to prevent races
# and to keep backups of the packages for emergency.
#
# APT::Archives::MaxSize "0"; (old, deprecated)
# APT::Periodic::MaxSize "0"; (new)
# - Set maximum size of the cache in MB (0=disable). If the cache
# is bigger, cached package files are deleted until the size
# requirement is met (the oldest packages will be deleted
# first).
#
# APT::Periodic::Update-Package-Lists "0";
# - Do "apt-get update" automatically every n-days (0=disable)
#
# APT::Periodic::Download-Upgradeable-Packages "0";
# - Do "apt-get upgrade --download-only" every n-days (0=disable)
#
# APT::Periodic::Download-Upgradeable-Packages-Debdelta "1";
# - Use debdelta-upgrade to download updates if available (0=disable)
#
# APT::Periodic::Unattended-Upgrade "0";
# - Run the "unattended-upgrade" security upgrade script
# every n-days (0=disabled)
# Requires the package "unattended-upgrades" and will write
# a log in /var/log/unattended-upgrades
#
# APT::Periodic::AutocleanInterval "0";
# - Do "apt-get autoclean" every n-days (0=disable)
#
# APT::Periodic::Verbose "0";
# - Send report mail to root
# 0: no report (or null string)
# 1: progress report (actually any string)
# 2: + command outputs (remove -qq, remove 2>/dev/null, add -d)
# 3: + trace on

check_stamp()
{
stamp="$1"
interval="$2"

if [ $interval -eq 0 ]; then
debug_echo "check_stamp: interval=0"
# treat as no time has passed
return 1
fi

if [ ! -f $stamp ]; then
debug_echo "check_stamp: missing time stamp file: $stamp."
# treat as enough time has passed
return 0
fi

# compare midnight today to midnight the day the stamp was updated
stamp_file="$stamp"
stamp=$(date --date=$(date -r $stamp_file --iso-8601) +%s 2>/dev/null)
if [ "$?" != "0" ]; then
# Due to some timezones returning 'invalid date' for midnight on
# certain dates (e.g. America/Sao_Paulo), if date returns with error
# remove the stamp file and return 0. See coreutils bug:
# http://lists.gnu.org/archive/html/bug-coreutils/2007-09/msg00176.html
rm -f "$stamp_file"
return 0
fi

now=$(date --date=$(date --iso-8601) +%s 2>/dev/null)
if [ "$?" != "0" ]; then
# As above, due to some timezones returning 'invalid date' for midnight
# on certain dates (e.g. America/Sao_Paulo), if date returns with error
# return 0.
return 0
fi

delta=$(($now-$stamp))

# interval is in days, convert to sec.
interval=$(($interval*60*60*24))
debug_echo "check_stamp: interval=$interval, now=$now, stamp=$stamp, delta=$delta (sec)"

# remove timestamps a day (or more) in the future and force re-check
if [ $stamp -gt $(($now+86400)) ]; then
echo "WARNING: file $stamp_file has a timestamp in the future: $stamp"
rm -f "$stamp_file"
return 0
fi

if [ $delta -ge $interval ]; then
return 0
fi

return 1
}

update_stamp()
{
stamp="$1"
touch $stamp
}

# we check here if autoclean was enough sizewise
check_size_constraints()
{
MaxAge=0
eval $(apt-config shell MaxAge APT::Archives::MaxAge)
eval $(apt-config shell MaxAge APT::Periodic::MaxAge)

MinAge=2
eval $(apt-config shell MinAge APT::Archives::MinAge)
eval $(apt-config shell MinAge APT::Periodic::MinAge)

MaxSize=0
eval $(apt-config shell MaxSize APT::Archives::MaxSize)
eval $(apt-config shell MaxSize APT::Periodic::MaxSize)

Cache="/var/cache/apt/archives/"
eval $(apt-config shell Cache Dir::Cache::archives/d)

# sanity check
if [ -z "$Cache" ]; then
echo "empty Dir::Cache::archives, exiting"
exit
fi

# check age
if [ ! $MaxAge -eq 0 ] && [ ! $MinAge -eq 0 ]; then
debug_echo "aged: ctime <$MaxAge and mtime <$MaxAge and ctime>$MinAge and mtime>$MinAge"
find $Cache -name "*.deb" \( -mtime +$MaxAge -and -ctime +$MaxAge \) -and -not \( -mtime -$MinAge -or -ctime -$MinAge \) -print0 | xargs -r -0 rm -f
elif [ ! $MaxAge -eq 0 ]; then
debug_echo "aged: ctime <$MaxAge and mtime <$MaxAge only"
find $Cache -name "*.deb" -ctime +$MaxAge -and -mtime +$MaxAge -print0 | xargs -r -0 rm -f
else
debug_echo "skip aging since MaxAge is 0"
fi

# check size
if [ ! $MaxSize -eq 0 ]; then
# maxSize is in MB
MaxSize=$(($MaxSize*1024))

#get current time
now=$(date --date=$(date --iso-8601) +%s)
MinAge=$(($MinAge*24*60*60))

# reverse-sort by mtime
for file in $(ls -rt $Cache/*.deb 2>/dev/null); do
du=$(du -s $Cache)
size=${du%%/*}
# check if the cache is small enough
if [ $size -lt $MaxSize ]; then
debug_echo "end remove by archive size: size=$size < $MaxSize"
break
fi

# check for MinAge of the file
if [ $MinAge -ne 0 ]; then
# check both ctime and mtime
mtime=$(stat -c %Y $file)
ctime=$(stat -c %Z $file)
if [ $mtime -gt $ctime ]; then
delta=$(($now-$mtime))
else
delta=$(($now-$ctime))
fi
if [ $delta -le $MinAge ]; then
debug_echo "skip remove by archive size: $file, delta=$delta < $MinAge"
break
else
# delete oldest file
debug_echo "remove by archive size: $file, delta=$delta >= $MinAge (sec), size=$size >= $MaxSize"
rm -f $file
fi
fi
done
fi
}

# deal with the Apt::Periodic::BackupArchiveInterval
do_cache_backup()
{
BackupArchiveInterval="$1"
if [ $BackupArchiveInterval -eq 0 ]; then
return
fi

# Set default values and normalize
CacheDir="/var/cache/apt"
eval $(apt-config shell CacheDir Dir::Cache/d)
CacheDir=${CacheDir%/}
if [ -z "$CacheDir" ]; then
debug_echo "practically empty Dir::Cache, exiting"
return 0
fi

Cache="${CacheDir}/archives/"
eval $(apt-config shell Cache Dir::Cache::Archives/d)
if [ -z "$Cache" ]; then
debug_echo "practically empty Dir::Cache::archives, exiting"
return 0
fi

BackupLevel=3
eval $(apt-config shell BackupLevel APT::Periodic::BackupLevel)
if [ $BackupLevel -le 1 ]; then
BackupLevel=2 ;
fi

Back="${CacheDir}/backup/"
eval $(apt-config shell Back Dir::Cache::Backup/d)
if [ -z "$Back" ]; then
echo "practically empty Dir::Cache::Backup, exiting" 1>&2
return
fi

CacheArchive="$(basename "${Cache}")"
test -n "${CacheArchive}" || CacheArchive="archives"
BackX="${Back}${CacheArchive}/"
for x in $(seq 0 1 $((${BackupLevel}-1))); do
eval "Back${x}=${Back}${x}/"
done

# backup after n-days if archive contents changed.
# (This uses hardlink to save disk space)
BACKUP_ARCHIVE_STAMP=/var/lib/apt/periodic/backup-archive-stamp
if check_stamp $BACKUP_ARCHIVE_STAMP $BackupArchiveInterval; then
if [ $({(cd $Cache 2>/dev/null; find . -name "*.deb"); (cd $Back0 2>/dev/null;find . -name "*.deb") ;}| sort|uniq -u|wc -l) -ne 0 ]; then
mkdir -p $Back
rm -rf $Back$((${BackupLevel}-1))
for y in $(seq $((${BackupLevel}-1)) -1 1); do
eval BackY=${Back}$y
eval BackZ=${Back}$(($y-1))
if [ -e $BackZ ]; then
mv -f $BackZ $BackY ;
fi
done
cp -la $Cache $Back ; mv -f $BackX $Back0
update_stamp $BACKUP_ARCHIVE_STAMP
debug_echo "backup with hardlinks. (success)"
else
debug_echo "skip backup since same content."
fi
else
debug_echo "skip backup since too new."
fi
}

# sleep for a random interval of time (default 30min)
# (some code taken from cron-apt, thanks)
random_sleep()
{
RandomSleep=1800
eval $(apt-config shell RandomSleep APT::Periodic::RandomSleep)
if [ $RandomSleep -eq 0 ]; then
return
fi
if [ -z "$RANDOM" ] ; then
# A fix for shells that do not have this bash feature.
RANDOM=$(( $(dd if=/dev/urandom bs=2 count=1 2> /dev/null | cksum | cut -d' ' -f1) % 32767 ))
fi
TIME=$(($RANDOM % $RandomSleep))
debug_echo "sleeping for $TIME seconds"
sleep $TIME
}


debug_echo()
{
# Display message if $VERBOSE >= 1
if [ "$VERBOSE" -ge 1 ]; then
echo $1 1>&2
fi
}

check_power(){
# laptop check, on_ac_power returns:
# 0 (true) System is on main power
# 1 (false) System is not on main power
# 255 (false) Power status could not be determined
# Desktop systems always return 255 it seems
if which on_ac_power >/dev/null; then
on_ac_power
POWER=$?
if [ $POWER -eq 1 ]; then
debug_echo "exit: system NOT on main power"
return 1
elif [ $POWER -ne 0 ]; then
debug_echo "power status ($POWER) undetermined, continuing"
fi
debug_echo "system is on main power."
fi
return 0
}

# ------------------------ main ----------------------------

if test -r /var/lib/apt/extended_states; then
# Backup the 7 last versions of APT's extended_states file
# shameless copy from dpkg cron
if cd /var/backups ; then
if ! cmp -s apt.extended_states.0 /var/lib/apt/extended_states; then
cp -p /var/lib/apt/extended_states apt.extended_states
savelog -c 7 apt.extended_states >/dev/null
fi
fi
fi

# check apt-config existence
if ! which apt-config >/dev/null ; then
exit 0
fi

# check if the user really wants to do something
AutoAptEnable=1 # default is yes
eval $(apt-config shell AutoAptEnable APT::Periodic::Enable)

if [ $AutoAptEnable -eq 0 ]; then
exit 0
fi

# Set VERBOSE mode from apt-config (or inherit from environment)
VERBOSE=0
eval $(apt-config shell VERBOSE APT::Periodic::Verbose)
debug_echo "verbose level $VERBOSE"
if [ "$VERBOSE" -le 2 ]; then
# quiet for 0,1,2
XSTDOUT=">/dev/null"
XSTDERR="2>/dev/null"
XAPTOPT="-qq"
XUUPOPT=""
else
XSTDOUT=""
XSTDERR=""
XAPTOPT=""
XUUPOPT="-d"
fi
if [ "$VERBOSE" -ge 3 ]; then
# trace output
set -x
fi

check_power || exit 0

# check if we can lock the cache and if the cache is clean
if which apt-get >/dev/null && ! eval apt-get check $XAPTOPT $XSTDERR ; then
debug_echo "error encountered in cron job with \"apt-get check\"."
exit 0
fi

# Global current time in seconds since 1970-01-01 00:00:00 UTC
now=$(date +%s)

# Support old Archive for compatibility.
# Document only Periodic for all controlling parameters of this script.

UpdateInterval=0
eval $(apt-config shell UpdateInterval APT::Periodic::Update-Package-Lists)

DownloadUpgradeableInterval=0
eval $(apt-config shell DownloadUpgradeableInterval APT::Periodic::Download-Upgradeable-Packages)

UnattendedUpgradeInterval=0
eval $(apt-config shell UnattendedUpgradeInterval APT::Periodic::Unattended-Upgrade)

AutocleanInterval=0
eval $(apt-config shell AutocleanInterval APT::Periodic::AutocleanInterval)

BackupArchiveInterval=0
eval $(apt-config shell BackupArchiveInterval APT::Periodic::BackupArchiveInterval)

Debdelta=1
eval $(apt-config shell Debdelta APT::Periodic::Download-Upgradeable-Packages-Debdelta)

# check if we actually have to do anything that requires locking the cache
if [ $UpdateInterval -eq 0 ] &&
[ $DownloadUpgradeableInterval -eq 0 ] &&
[ $UnattendedUpgradeInterval -eq 0 ] &&
[ $BackupArchiveInterval -eq 0 ] &&
[ $AutocleanInterval -eq 0 ]; then

# check cache size
check_size_constraints

exit 0
fi

# deal with BackupArchiveInterval
do_cache_backup $BackupArchiveInterval

# sleep random amount of time to avoid hitting the
# mirrors at the same time
random_sleep
check_power || exit 0

# include default system language so that "apt-get update" will
# fetch the right translated package descriptions
if [ -r /etc/default/locale ]; then
. /etc/default/locale
export LANG LANGUAGE LC_MESSAGES LC_ALL
fi

# update package lists
UPDATED=0
UPDATE_STAMP=/var/lib/apt/periodic/update-stamp
if check_stamp $UPDATE_STAMP $UpdateInterval; then
# check for a new archive signing key (against the master keyring)
if eval apt-key net-update $XSTDERR; then
debug_echo "apt-key net-update (success)"
else
debug_echo "apt-key net-update (failure)"
fi
# run apt-get update
if eval apt-get $XAPTOPT -y update $XSTDERR; then
debug_echo "download updated metadata (success)."
if which dbus-send >/dev/null && pidof dbus-daemon >/dev/null; then
if dbus-send --system / app.apt.dbus.updated boolean:true ; then
debug_echo "send dbus signal (success)"
else
debug_echo "send dbus signal (error)"
fi
else
debug_echo "dbus signal not send (command not available)"
fi
update_stamp $UPDATE_STAMP
UPDATED=1
# now run apt-xapian-index if it is installed to ensure the index
# is up-to-date
if [ -x /usr/sbin/update-apt-xapian-index ]; then
nice ionice -c3 update-apt-xapian-index -q -u
fi
else
debug_echo "download updated metadata (error)"
fi
else
debug_echo "download updated metadata (not run)."
fi

# download all upgradeable packages (if it is requested)
DOWNLOAD_UPGRADEABLE_STAMP=/var/lib/apt/periodic/download-upgradeable-stamp
if [ $UPDATED -eq 1 ] && check_stamp $DOWNLOAD_UPGRADEABLE_STAMP $DownloadUpgradeableInterval; then
if [ $Debdelta -eq 1 ]; then
debdelta-upgrade >/dev/null 2>&1 || true
fi
if eval apt-get $XAPTOPT -y -d dist-upgrade $XSTDERR; then
update_stamp $DOWNLOAD_UPGRADEABLE_STAMP
debug_echo "download upgradable (success)"
else
debug_echo "download upgradable (error)"
fi
else
debug_echo "download upgradable (not run)"
fi

# auto upgrade all upgradeable packages
UPGRADE_STAMP=/var/lib/apt/periodic/upgrade-stamp
if which unattended-upgrade >/dev/null && check_stamp $UPGRADE_STAMP $UnattendedUpgradeInterval; then
if unattended-upgrade $XUUPOPT; then
update_stamp $UPGRADE_STAMP
debug_echo "unattended-upgrade (success)"
else
debug_echo "unattended-upgrade (error)"
fi
else
debug_echo "unattended-upgrade (not run)"
fi

# autoclean package archive
AUTOCLEAN_STAMP=/var/lib/apt/periodic/autoclean-stamp
if check_stamp $AUTOCLEAN_STAMP $AutocleanInterval; then
if eval apt-get $XAPTOPT -y autoclean $XSTDERR; then
debug_echo "autoclean (success)."
update_stamp $AUTOCLEAN_STAMP
else
debug_echo "autoclean (error)"
fi
else
debug_echo "autoclean (not run)"
fi

# check cache size
check_size_constraints

#
# vim: set sts=4 ai :
#