#! /bin/sh
###
### Manage the backup archive structure
###
### (c) 2011 Mark Wooding
###

###----- Licensing notice ---------------------------------------------------
###
### This file is part of the distorted.org.uk backup suite.
###
### distorted-backup is free software; you can redistribute it and/or modify
### it under the terms of the GNU General Public License as published by
### the Free Software Foundation; either version 2 of the License, or
### (at your option) any later version.
###
### distorted-backup is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
### GNU General Public License for more details.
###
### You should have received a copy of the GNU General Public License along
### with distorted-backup; if not, write to the Free Software Foundation,
### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

set -e

## Configuration and testing.
: ${BKP=/mnt/bkp} ${META=/mnt/bkpmeta}
: ${KEYS=/etc/keys}

case $(id -u) in 0) ;; *) exec userv root bkpadmin "$@" ;; esac

###--------------------------------------------------------------------------
### Common utilities.

quis=${0##*/}
version="@VERSION@"

moan () {
  ## Print a complaint to standard error.

  echo >&2 "$quis: $*"
}

die () {
  ## Print a complaint and exit.

  moan "$*"
  exit 1
}

cleanups=""
addcleanup () {
  cmd=$1
  ## Add a cleanup command CMD to the list.

  case "$cleanups" in
    ?*)
      ;;
    *)
      trap 'rc=$?; for c in $cleanups; do $c; done; exit $rc' \
	EXIT INT TERM
      ;;
  esac
  cleanups=${cleanups+$cleanups }$cmd
}

rmtmp () { case ${tmpdir+t} in t) rm -rf "$tmpdir" ;; esac }
addcleanup rmtmp
mktmp () {
  ## Make a temporary directory and output its name.

  case "${tmpdir+t}" in
    t)
      ;;
    *)
      i=0
      while :; do
	r=$(openssl rand -base64 12)
	tmpdir=${TMPDIR-/tmp}/$quis.$$.$r
	if mkdir -m700 "$tmpdir" >/dev/null 2>&1; then break; fi
	case $i in ???) die "failed to create temporary directory" ;; esac
	i=$(( $i + 1 ))
      done
      ;;
  esac
  echo "$tmpdir"
}

###--------------------------------------------------------------------------
### Command dispatch.

case "${USERV_USER+t}" in t) uservp=t ;; *) uservp=nil ;; esac

USAGE="COMMAND [ARGUMENT ...]"
cmdname=""
cmdargs=$USAGE
cmds=""
_defcmd () {
  name=$1; shift; args=$*
  ## Define a command unconditionally.

  cmds="${cmds:+$cmds
}$name $args"
}

defcmd () {
  ## Define a command for privileged users only.

  case $uservp in nil) _defcmd "$@" ;; esac
}

defucmd () {
  ## Define a command usable via userv.

  _defcmd "$@"
}

usage () {
  ## Write a usage message for the current command.

  echo "usage: $quis${cmdname:+ $cmdname}${cmdargs:+ $cmdargs}"
}

usage_err () {
  ## Fail with a usage error.

  usage >&2
  exit 1
}

lookupcmd () {
  cmd=$1
  ## Try to loop up the command CMD.

  while read cmdname cmdargs; do
    case $cmdname in "$cmd") return ;; esac
  done <<EOF
$cmds
EOF
  die "unknown command \`$cmd'"
}

defucmd help
cmd_help () {
  case $# in 0) ;; *) usage_err ;; esac

  cat <<EOF
$quis, version $version

usage: $quis $USAGE

Commands provided:
EOF
  while read cmd args; do
    echo "	$cmd${args:+ $args}"
  done <<EOF
$cmds
EOF
}

###--------------------------------------------------------------------------
### Utility functions.

sign () {
  file=$1
  ## Sign the named FILE, producing a signature FILE.sig.

  seccure-sign -F$KEYS/priv/backup-auth -cp256 -s"$file.sig" <"$file"
}

checkhost () {
  ## Check that a host is defined.

  case "${host+t}" in
    t) ;; *) die "no host defined (use \`-H')" ;;
  esac
}

checkthing () {
  thing=$1 good=$2 what=$3 string=$4
  ## Check that STRING is a valid THING -- i.e., it only consists of GOOD
  ## characters.

  case "$string" in
    *[!$good]*)
      die "bad $thing \`$string' given for $what"
      ;;
  esac
}

checknum () {
  what=$1 string=$2
  ## Check that STRING is at least plausibly numeric.

  checkthing number "0-9" "$what" "$string"
}

checkpath () {
  what=$1 string=$2
  ## Check that STRING is a plausible pathname.

  case "$string" in
    .* | */.* | *[!-a-zA-Z0-9.,_#!%^+=@/:]*)
      die "bad pathname \`$string' given for $what"
      ;;
  esac
}

checkword () {
  what=$1 thing=$2
  ## Check that THING doesn't need shell quoting, and doesn't interfere with
  ## other common delimiter characters.  (Colons aren't allowed because they
  ## mess up /etc/passwd; slashes aren't allowed because they're directory
  ## separators.  Leading dots aren't allowed either.  Hashes seem OK.)

  checkthing word "-a-zA-Z0-9.,_#!%^+=@" "$what" "$string"
}

domkdir () {
  dir=$1 owner=$2 mode=$3
  ## Make a directory and set permissions on it.

  mkdir -m755 "$dir"
  chown $owner "$dir"
  chmod $mode "$dir"
}

###--------------------------------------------------------------------------
### Volume and volume group maintenance.

currenttag () {
  ## Output the tag of the mounted backup volume group.

  dev=$(mntdev $BKP)
  case "$dev" in
    /dev/mapper/cbkp-*) echo "${dev#*-}"; return ;;
    *) die "failed to parse tag from device name \`$dev'" ;;
  esac
}

guesstag () {
  ## Guess and print the tag of the available backup volume group.  If there
  ## is not exactly one volume group available, print an error and fail.

  LVM_SUPPRESS_FD_WARNINGS=t vgs @backup --noheadings -o name,attr | {
    match=""
    while read name attr; do
      case "$name" in bkp-*) ;; *) continue ;; esac
      case "$attr" in ??x*) continue ;; esac
      match="$match${match:+ }${name#bkp-}"
    done
    case "x$match" in
      x) die "no backup volume groups available" ;;
      x*\ *) die "multiple backup volume groups available: $match" ;;
    esac
    echo "$match"
  }
}

mntdev () {
  dir=$1
  ## Output a device name for the filesystem mounted on DIR.

  dev=$(mountpoint -d "$dir")
  devname=$(udevadm info --query=name --path="/dev/block/$dev")
  case "$devname" in
    dm-*)
      devname=mapper/$(dmsetup info -c --noheadings -oname "/dev/$devname")
      ;;
  esac
  echo "/dev/$devname"
}

mntmeta () {
  tag=$1
  ## Mount the metadata volume of the backup volume group named TAG.

  if ! mountpoint -q $META; then
    mount "/dev/bkp-$tag/meta" $META
  fi
}

cryptkey () {
  ## Decrypt and output the key for the encrypted volume.  This assumes that
  ## the metadata volume is already mounted on /mnt/bkpmeta.

  seccure-decrypt -q -m128 -cp256 -F$KEYS/priv/backup-disk <$META/cur/blob
}

decrypt () {
  tag=$1
  ## Decrypt but don't mount the encrypted volume of the backup volume group
  ## named TAG.

  mntmeta "$tag"
  if [ ! -b "/dev/mapper/cbkp-$tag" ]; then
    cryptkey | cryptsetup luksOpen --key-file=- \
      "/dev/bkp-$tag/crypt" "cbkp-$tag"
  fi
}

mntcrypt () {
  tag=$1
  ## Mount the encrypted subvolume of the backup volume group named TAG.  The
  ## metadata volume will be mounted if necessary.

  decrypt "$tag"
  if ! mountpoint -q $BKP; then
    mount "/dev/mapper/cbkp-$tag" $BKP
  fi
}

umnt () {
  ## Unmounts a backup volume group: both the encrypted and metadata volumes
  ## are unmounted.

  if mountpoint -q $BKP; then
    tag=$(currenttag) cryptclosep=t
  else
    cryptclosep=nil
  fi
  for i in bkp bkpmeta; do
    if mountpoint -q /mnt/$i; then umount /mnt/$i; fi
  done
  case $cryptclosep in
    t)
      if [ -b "/dev/mapper/cbkp-$tag" ]; then
	cryptsetup luksClose "cbkp-$tag"
      fi
  esac
}

defcmd initvol TAG DEVICE
cmd_initvol () {
  case $# in 2) ;; *) usage_err ;; esac
  tag=$1 dev=$2

  vgcreate --addtag @backup "bkp-$tag" "$dev"

  lvcreate -L4M -nmeta "bkp-$tag"
  mkfs -text2 -Lmeta "/dev/bkp-$tag/meta"
  mntmeta "$tag"

  mkdir -m755 $META/new
  dd if=/dev/random bs=1 count=512 |
  seccure-encrypt -m128 $(cat $KEYS/pub/backup-disk.pub) >$META/new/blob
  mv $META/new $META/cur

  lvcreate -l100%FREE -ncrypt "bkp-$tag"
  cryptkey | cryptsetup luksFormat \
    --cipher=twofish-xts-benbi:sha256 --hash=sha256 \
    "/dev/bkp-$tag/crypt" -
  decrypt "$tag"
  mkfs -text2 -Lbackup -i1048576 "/dev/mapper/cbkp-$tag"
  mntcrypt "$tag"
}

defucmd mount "[TAG]"
cmd_mount () {
  case $# in
    0) tag=$(guesstag) check=nil ;;
    1) tag=$1 check=t ;;
    *) usage_err ;;
  esac

  if mountpoint -q $BKP; then
    curtag=$(currenttag)
    case "$check,$curtag" in "t,$tag") ;; t*) exit 1 ;; esac
  else
    mntcrypt "$tag"
  fi
}

defcmd umount
cmd_umount () {
  case $# in 0) ;; *) usage_err ;; esac
  mntp=nil
  for i in bkp bkpmeta; do
    if mountpoint -q /mnt/$i; then mntp=t; fi
  done
  case $mntp in
    nil) die "backup volume not mounted" ;;
  esac
  umnt
}

###--------------------------------------------------------------------------
### Archive maintenance.

checkdir () {
  key=$1 dir=$2
  ## Check a directory which has `hashes' and `hashes.sig' files.

  if ! seccure-verify -q -i"$dir/hashes" -- \
    $(cat "$KEYS/$key") $(cat "$dir/hashes.sig")
  then
    die "failed to verify signature for \`$dir'"
  fi

  cd "$dir"
  sha256sum --quiet -c hashes

  tmpdir=$(mktmp)
  find . -type f -print | sed 's:^\./::' | sort >"$tmpdir/present"
  { echo hashes
    echo hashes.sig
    sed 's/^[a-f0-9]*[* ] //' hashes
  } | sort >"$tmpdir/checked"
  cd "$tmpdir"
  diff -u checked present
}

fixperms () {
  dir=$1 owner=$2 fmode=$3 dmode=$4
  ## Fix the directory tree DIR so that everything is owned by OWNER (a
  ## USER:GROUP pair) and has modes FMODE for files and DMODE for
  ## directories.

  ## Change all of the ownerships.  This will prevent anyone else from
  ## changing the permissions on the files.  This assumes that chown(1) is
  ## secure in recursive mode; I've checked that GNU chown seems correct.
  chown -R $owner "$dir"

  ## Paranoia: check that we correctly changed all of the files.
  u=${owner%:*} g=${owner#*:}
  (cd "$dir"; find . ! \( -user $u -group $g \) -ls) |
  if read line; then
    moan "failed to fix permssions on \`$dir'"
    { echo $line; cat; } | sed 's/^/	/'
    exit 1
  fi

  ## Now get to work on the file and directory permissions.
  find "$dir" -type d -print0 | xargs -0r chmod $dmode
  find "$dir" ! -type d -print0 | xargs -0r chmod $fmode
}

commitdir () {
  dir=$1 target=$2
  ## Commit an `prepare' directory DIR, moving its `incoming' files to
  ## TARGET.  This will choose the correct name for the directory, but
  ## assumes that it's already correctly laid out.  We assume that the
  ## permissions on this directory are safe (e.g., they've already been fixed
  ## using `fixperms').  On successful exit, DIR won't exist any more.  The
  ## shell variable `label' is set to the resulting archive name.

  ## If there's no `incoming' directory, then there's nothing to do.  Just
  ## zap the directory and move on.
  if [ ! -d "$dir/incoming" ]; then
    rm -rf "$dir"
    return
  fi

  ## Find the datestamp and level numbers to use for this directory.  These
  ## are created before the `incoming' directory, so they ought to exist.
  read level date time tz <"$dir/meta"

  ## Find a suitable sequence number for the target.  This is rather ugly;
  ## sorry.
  seq=1
  while :; do
    anyp=nil
    for i in "$target"/"$date#$seq".*; do
      if [ -e "$i" ]; then anyp=t; break; fi
    done
    case $anyp in nil) break ;; esac
    seq=$(( $seq + 1 ))
  done

  ## Move the directory.
  label="$date#$seq.$level"
  mv "$dir/incoming" "$target/$label"
  rm -rf "$dir"

  ## Update the catalogue.  Replace an existing dump at the same level.
  ## Assume that dates are monotonically increasing: add the new entry at the
  ## end.
  { found=nil
    while read lab l d t; do
      if [ $l -ne $level ]; then echo $label $l $d $t; fi
    done <"$target"/CATALOGUE
    echo $level $date $time $tz
  } >"$target"/CATALOGUE.new
  mv "$target"/CATALOGUE.new "$target"/CATALOGUE
}

defcmd initmeta
cmd_initmeta () {
  case $# in 0) ;; *) usage_err ;; esac

  ## Make a `new' directory and start recording our files.
  cd $META
  rm -rf new
  mkdir -m755 new
  f=""

  ## Copy the blob from the existing metadata.
  cp cur/blob new/
  f="$f blob"

  ## Archive the key recovery information.
  cd $KEYS
  tar cfz $META/new/keys.tgz pub/ recov/
  f="$f keys.tgz"

  ## Copy user and group information.
  cd $META/new
  for i in passwd group; do
    grep -E '^(root|backup|bkp-[[:alnum:]]+):' /etc/$i >$i
  done
  f="$f passwd group"

  ## Build the hashes file, and sign it.
  chown root:root $f
  chmod 644 $f
  sha256sum $f >hashes
  sign hashes

  ## Replace the old metadata.
  cd $META
  mv cur old
  mv new cur
  rm -rf old
}

defcmd chkmeta
cmd_chkmeta () {
  case $# in 0) ;; *) usage_err ;; esac

  checkdir pub/backup-auth.pub $META/cur
}

today () {
  ## Report the current date, as ISO8601.  Allow an override.

  case "${forceday+t}" in t) echo "$forceday" ;; *) date +%Y-%m-%d ;; esac
}

defucmd prep ASSET LEVEL \[DATE TIME TZ]
cmd_prep () {
  case $# in
    2) set -- "$@" $(today) $(date +%H:%M:%S) $(date +%z) ;;
    5) ;;
    *) usage_err ;;
  esac
  asset=$1 level=$2 date=$3 time=$4 tz=$5
  checkhost
  checkword asset "$asset"
  checknum level "$level"
  checkthing date -0-9 date "$date"
  checkthing time :0-9 time "$time"
  checkthing timezone -+0-9 tz "$tz"

  ## Make the host and asset directories if necessary.
  cd $BKP
  for i in $host $asset; do
    if [ ! -d $i ]; then domkdir $i root:root 755; fi
    cd $i
  done
  if [ ! -d failed ]; then domkdir failed root:root 755; fi
  for i in . failed; do
    if [ ! -f $i/CATALOGUE ]; then
      touch $i/CATALOGUE
      chown root:root $i/CATALOGUE
      chmod 644 $i/CATALOGUE
    fi
  done

  ## If an existing dump is in progress then archive it as a failure.
  if [ -d prepare ]; then
    if [ -d prepare/incoming ]; then
      fixperms prepare/incoming root:root 640 755
    fi
    commitdir prepare failed/
  fi

  ## Make a new preparation directory.
  domkdir prepare root:bkp-$host 755
  echo $level $date $time $tz >prepare/meta
  domkdir prepare/incoming bkp-$host:bkp-$host 2775

  ## Print the directory name.
  echo $BKP/$host/$asset/prepare/incoming
}

defucmd abort ASSET
cmd_abort () {
  case $# in 1) ;; *) usage_err ;; esac
  asset=$1
  checkhost
  checkword asset "$asset"

  ## Check that there's something to abort.
  cd $BKP
  if [ ! -d $host/$asset/prepare ]; then
    die "no dump in progress for $host/$asset"
  fi

  ## Just throw it away.
  rm -rf $host/$asset/prepare
}

defucmd fail ASSET
cmd_fail () {
  case $# in 1) ;; *) usage_err ;; esac
  asset=$1
  checkhost
  checkword asset "$asset"

  ## Check that there's something to fail.
  cd $BKP
  if [ ! -d $host/$asset/prepare ]; then
    die "no dump in progress for $host/$asset"
  fi

  ## Archive the failure.  This shouldn't be used to determine dump levels or
  ## we'll have gaps when things get sorted out.
  cd $host/$asset
  if [ -d prepare/incoming ]; then
    fixperms prepare/incoming root:root 640 755
  fi
  commitdir prepare failed/
}

julian () {
  date=$1
  ## Convert an ISO8601 DATE to a Julian Day Number.

  ## Extract the components of the date and trim leading zeros (which will
  ## cause things to be interpreted as octal and fail).
  year=${date%%-*} rest=${date#*-}; month=${rest%%-*} day=${rest#*-}
  year=${year#0} month=${month#0} day=${day#0}

  ## The actual calculation: convert a (proleptic) Gregorian calendar date
  ## into a Julian day number.  This is taken from Wikipedia's page
  ## http://en.wikipedia.org/wiki/Julian_day#Calculation but the commentary
  ## is mine.  The epoch is 4713BC-01-01 (proleptic) Julian, or 4714BC-11-24
  ## proleptic Gregorian.

  ## If the MONTH is January or February then set a = 1, otherwise set a = 0.
  a=$(( (14 - $month)/12 ))

  ## Compute a year offset relative to 4799BC-03-01.  This puts the leap day
  ## as the very last day in a year, which is very convenient.  The offset
  ## here is sufficient to make all y values positive (within the range of
  ## the JDN calendar), and is a multiple of 400, which is the Gregorian
  ## cycle length.
  y=$(( $year + 4800 - $a ))

  ## Compute the offset month number in that year.  These months count from
  ## zero, not one.
  m=$(( $month + 12*$a - 3 ))

  ## Now for the main event.  The (153 m + 2)/5 term is a surprising but
  ## correct trick for obtaining the number of days in the first m months of
  ## the (shifted) year).  The magic offset 32045 is what you get when you
  ## plug the proper JDN epoch (year = -4713, month = 11, day = 24) into the
  ## above machinery.
  jdn=$(( $day + (153*$m + 2)/5 + 365*$y + $y/4 - $y/100 + $y/400 - 32045 ))

  echo $jdn
}

dumplevel () {
  fulldate=$1 lastdate=$2
  ## Return the dump level, given that the most recent full dump occurred on
  ## FULLDATE and the most revent dump of any kind occurred on LASTDATE.

  ## Actually, we're much more interested in the day difference between these
  ## two times.
  fulljdn=$(julian $fulldate)
  lastjdn=$(julian $lastdate)
  now=$(today); nowjdn=$(julian $now)
  lastday=$(( $lastjdn - $fulljdn ))
  today=$(( $nowjdn - $fulljdn ))

  ## If the difference is greater than 512 then we know we should do a full
  ## dump.  (This provides an upper bound for the search below.  It should
  ## never happen in practice, of course.)
  if [ $(( $today - $lastday )) -ge 512 ]; then echo 0; return; fi

  ## Now we work out the correct dump level.  This will assume that the
  ## previous dump had a sensible level.  If dumps are omitted, then we will
  ## choose a lower (more comprehensive) dump level than the schedule calls
  ## for; such an overestimation will mean that we will probably end up
  ## dumping too much again.  This is the right error to make.
  ##
  ## We use a Towers of Hanoi schedule.  If we're doing dumps every day, then
  ## on day n since the last full dump, we work out the dump level as
  ## follows: write n = 2^s t where t is odd (i.e., s is the number of
  ## trailing zero bits in the binary representation of n); then the dump
  ## level on day n is 9 - s.  This is enough for 512 days without a full
  ## dump, and it fails gracefully anyway.
  ##
  ## Now we have to deal with the problem of skipping dumps.  Suppose the
  ## last dump was on day m = 2^u v, and it's now day n = 2^s t.  We ought to
  ## take the lowest dump level of any intervening day, i.e., the dump level
  ## is 9 - a for the largest a such that there exists b with m < l = 2^a b
  ## <= n.  We claim that such an l is unique.  Suppose, to the contrary,
  ## that m < 2^a b < 2^a b' <= n, with both b and b' odd.  Then m < 2^{a+1}
  ## (b + 1)/2 <= n, contradicting maximality of a.
  ##
  ## How does this help?  Observe that n = 2^s t = 2^a b + o, for some o <
  ## 2^a: if o >= 2^a then 2^a (b + 1) <= n contradicting uniqueness of l.
  ## Similarly, m = 2^u v = 2^a b - r, for some r <= 2^a (otherwise m <
  ## 2^a (b - 1), again contradicting uniqueness).  Therefore, m and n are
  ## identical from bit a + 1 onwards, and differ at bit a.  In other words,
  ## a is the position of the most significant set bit in m XOR n.
  diff=$(( lastday ^ today ))

  ## We know that the bit position must be less than 16.
  t=16 n=0
  while [ $diff -gt 1 ]; do
    xx=$(( $diff >> $t ))
    if [ $xx -gt 0 ]; then
      diff=$xx n=$(( $n + $t ))
    fi
    t=$(( $t >> 1 ))
  done

  echo $(( 9 - $n ))
}

defucmd level ASSET
cmd_level () {
  case $# in 1) ;; *) usage_err ;; esac
  asset=$1
  checkhost
  checkword asset "$asset"

  ## Set the correct directory.  If it doesn't exist then we obviously need a
  ## level-0 dump.
  cd $BKP
  full="0 1970-01-01 00:00:00 +0000"
  if [ ! -d $host/$asset ]; then echo $full; return; fi
  cd $host/$asset

  ## We need the time of the most recent dump of any kind, and the most
  ## recent level-zero dump.
  fulldate=none lastdate=none
  while read label level date time tz; do
    if [ $level -eq 0 ]; then fulldate=$date; fi
    lastdate=$date
  done <CATALOGUE
  case $fulldate in none) echo $full; return ;; esac
  level=$(dumplevel $fulldate $lastdate)

  ## Determine the time of the most recent dump of the same or more inclusive
  ## level.
  date=none
  while read lab l d t; do
    if [ $l -le $level ]; then date=$d time=$t; fi
  done <CATALOGUE
  echo $level $date $time $tz
}

defucmd hash ASSET FILE HASH
cmd_hash () {
  case $# in 3) ;; *) usage_err ;; esac
  asset=$1 file=$2 hash=$3
  checkword asset "$asset"
  checkpath file "$file"
  checkword hash "$hash"

  cd $BKP/$host/$asset/prepare

  if [ -f hashes ]; then
    while read h f; do
      case "$f" in "$file") die "file \`$file' already hashed" ;; esac
    done <hashes
    cp hashes hashes.new
  fi
  echo "$hash  $file" >>hashes.new
  mv hashes.new hashes
}

defucmd commit ASSET
cmd_commit () {
  case $# in 1) ;; *) usage_err ;; esac
  asset=$1
  checkhost
  checkword asset "$asset"

  cd $BKP/$host/$asset/prepare
  fixperms incoming root:bkp-$host 640 755
  findargs=""

  if [ -f hashes ]; then
    while read hash name; do
      if [ ! -f "incoming/$name" ]; then
	die "precomputed hash for nonexistent or non-file \`$name'"
      fi
      findargs="$findargs ! -path incoming/$name"
    done <hashes
    cp hashes hashes.calc
  fi

  find incoming -type f $findargs -print0 | \
    xargs -0r sha256sum | \
    sed 's:  incoming/:  :' \
    >>hashes.calc
  sort -k2 hashes.calc >incoming/hashes
  sign incoming/hashes
  chmod 640 incoming/hashes incoming/hashes.sig
  chown root:bkp-$host incoming/hashes incoming/hashes.sig

  cd ..
  commitdir prepare .
  echo "$label"
}

defucmd check ASSET LABEL
cmd_check () {
  case $# in 2) ;; *) usage_err ;; esac
  asset=$1 label=$2
  checkhost
  checkword asset "$asset"
  checkword label "$label"

  checkdir pub/backup-auth.pub $BKP/$host/$asset/$label
}

defucmd catalogue ASSET
cmd_catalogue () {
  case $# in 1) ;; *) usage_err ;; esac
  asset=$1
  checkhost
  checkword asset "$asset"

  cat $BKP/$host/$asset/CATALOGUE
}

defucmd outdated ASSET
cmd_outdated () {
  case $# in 1) ;; *) usage_err ;; esac
  asset=$1
  checkhost
  checkword asset "$asset"

  cd $BKP/$host/$asset
  for i in [0-9]*#*.*; do
    if [ -d "$i" ]; then echo "$i"; fi
  done |
  sort -rn |
  { best=10
    while read tag; do
      date=${tag%%#*} level=${tag##*.}
      if [ $level -le $best ]
      then best=$level
      else echo "$tag"
      fi
    done
  }
}

###--------------------------------------------------------------------------
### Main program.

defcmd test CMD '[ARGS ...]'
cmd_test () { "$@"; }

case $uservp in
  t)
    host=${USERV_USER#bkp-}
    opts="h"
    ;;
  nil)
    unset host
    opts="hH:D:"
    ;;
esac

while getopts "$opts" opt; do
  case "$opt" in
    h) cmd_help; exit ;;
    H) host=$OPTARG ;;
    D) forceday=$OPTARG ;;
    *) usage_err ;;
  esac
done
shift $(( $OPTIND - 1 ))

case $# in 0) usage_err ;; esac
lookupcmd "$1"; shift
cmd_$cmdname "$@"

###----- That's all, folks --------------------------------------------------