#!/bin/sh
set -e

test "$1" = 'configure' || exit 0

errcho () {
  echo "$*" >&2
}

check_uidgid () {
  USER=$1
  ID=$2
  GROUP=$3
  GID=$4
  HOM=$5

  # check for user
  ID_=`id -u ${USER} 2>/dev/null` || return 1
  if test "$ID_" -ne "$ID"; then
    errcho "$USER: uid must be \"$ID\", not \"$ID_\"."
    return 2
  fi
  # check group
  GROUP_=`id -gn ${USER} 2>/dev/null` || return 100
  if test "$GROUP_" != "$GROUP"; then
    errcho "$USER: must be group \"$GROUP\", not \"$GROUP_\"."
    return 3
  fi
  GID_=`id -g ${USER} 2>/dev/null` || return 100
  if test "$GID" -ne 0 && test "$GID_" -ne "$GID"; then
    errcho "$GROUP: gid must be \"$GID\", not \"$GID_\"."
    return 4
  fi
  # check home
  HOM_=`grep -E "^$USER:*" /etc/passwd | cut -d : -f 6` || return 100
  if test "$HOM_" != "$HOM"; then
    errcho "$USER: home must be \"$HOM\", not \"$HOM_\"."
    return 5
  fi
  # ok
  return 0
}
add_usersgroups () {
  DEBUG=$*

  $DEBUG groupadd -g 64010 qmail || return 1
  $DEBUG addgroup --system nofiles || return 1
  $DEBUG useradd -u 64010 -g nofiles -d /var/lib/qmail/alias alias || return 1
  $DEBUG useradd -u 64011 -g nofiles -d /var/lib/qmail qmaild || return 1
  $DEBUG useradd -u 64015 -g nofiles -d /var/lib/qmail qmaill || return 1
  $DEBUG useradd -u 64016 -g nofiles -d /var/lib/qmail qmailp || return 1
  $DEBUG useradd -u 64014 -g qmail -d /var/lib/qmail qmailq || return 1
  $DEBUG useradd -u 64013 -g qmail -d /var/lib/qmail qmailr || return 1
  $DEBUG useradd -u 64012 -g qmail -d /var/lib/qmail qmails || return 1
  # done
  return 0
}
check_user () {
  getent passwd "$1" >/dev/null || return 0
  errcho "user \"$1\" found in the passwd database."
  return 1
}
check_uid () {
  getent passwd "$1" >/dev/null || return 0
  errcho "uid \"$1\" found in the passwd database."
  return 1
}
check_gid () {
  getent group "$1" >/dev/null || return 0
  errcho "gid \"$1\" found in the group database."
  return 1
}
check_group () {
  getent group "$1" >/dev/null || return 0
  errcho "group \"$1\" found in the group database."
  return 1
}
stopinst () {
  cat <<EOT >&2

You must have the following entries in /etc/passwd and /etc/group to install
the Debian qmail packages on this system; if none of these users and groups
exist yet, this package will add them automatically.

/etc/passwd:
alias:x:64010:XXXXX:qmail alias:/var/lib/qmail/alias:/bin/sh
qmaild:x:64011:XXXXX:qmail daemon:/var/lib/qmail:/bin/sh
qmails:x:64012:64010:qmail send:/var/lib/qmail:/bin/sh
qmailr:x:64013:64010:qmail remote:/var/lib/qmail:/bin/sh
qmailq:x:64014:64010:qmail queue:/var/lib/qmail:/bin/sh
qmaill:x:64015:XXXXX:qmail log:/var/lib/qmail:/bin/sh
qmailp:x:64016:XXXXX:qmail pw:/var/lib/qmail:/bin/sh
/etc/group:
qmail:x:64010:
nofiles:x:XXXXX:

Where XXXXX is an abritary system group id for the 'nofiles' group.

Installation aborted.

EOT
  exit 1
}

# check uids and gids
ALIAS="alias 64010 nofiles 0 /var/lib/qmail/alias"
QMAILD="qmaild 64011 nofiles 0 /var/lib/qmail"
QMAILL="qmaill 64015 nofiles 0 /var/lib/qmail"
QMAILP="qmailp 64016 nofiles 0 /var/lib/qmail"
QMAILQ="qmailq 64014 qmail 64010 /var/lib/qmail"
QMAILR="qmailr 64013 qmail 64010 /var/lib/qmail"
QMAILS="qmails 64012 qmail 64010 /var/lib/qmail"

RC=0
check_uidgid $ALIAS || RC=$?
if test "$RC" -eq 1; then
  # check for any existing qmail-groups
  for i in alias qmaild qmaill qmailp qmailq qmailr qmails; do
    check_user $i || stopinst
  done
  check_group qmail || stopinst
  for i in 64010 64011 64012 64013 64014 64015 64016; do
    check_uid $i || stopinst
  done
  check_gid 64010 || stopinst
  cat <<EOT
No qmail-users or -groups found.

This script runs the following commands, without adding these users and
groups, this qmail-package cannot run on this system.

`add_usersgroups "echo # "`

EOT
  if ! add_usersgroups; then
    errcho "failed."
    stopinst
  fi
  RC=0
fi
test "$RC" -eq 0 || stopinst

RC=0
check_uidgid $ALIAS  || RC=$?
check_uidgid $QMAILD || RC=$?
check_uidgid $QMAILL || RC=$?
check_uidgid $QMAILP || RC=$?
check_uidgid $QMAILQ || RC=$?
check_uidgid $QMAILR || RC=$?
check_uidgid $QMAILS || RC=$?
test "$RC" -eq 0 || stopinst

echo "qmail uids and gids ok."