opt/bin/become

   1 #!/bin/bash
   2
   3 kerberos=0
   4 x11=0
   5 while getopts ":kx" opt; do
   6   case $opt in
   7     k) kerberos=1;;
   8     x) x11=1;;
   9   esac
  10 done
  11 shift $((OPTIND-1))
  12
  13 user="$1"; shift
  14 if [ -z "$user" ]; then
  15   echo >&2 "Usage: become [-k] [-x] <user>"
  16   echo >&2 "Options: -k   Delegate Kerberos credentials even if target user is not root."
  17   echo >&2 "         -x   Delegate X11 cookie even if target user is not root."
  18   exit 1
  19 fi
  20
  21 uid=$(PATH=/usr/xpg4/bin:/usr/bin id -u "$user" 2>/dev/null)
  22 if [ -z "$uid" ]; then
  23   echo >&2 "Who is $user?"
  24   exit 2
  25 fi
  26
  27 if [ $uid = 0 ]; then
  28   kerberos=1
  29   x11=1
  30 fi
  31
  32 PRINCIPAL=$(klist 2>/dev/null | sed -n 's/^Default principal: //p')
  33 if [ $x11 = 1 -a -n "$DISPLAY" -a "${DISPLAY##localhost:}" = "$DISPLAY" ]; then
  34   COOKIE="$(xauth list $DISPLAY)"
  35 fi
  36 BECOME="$HOME/.become"
  37 profile="$BECOME/$user"
  38 [ -f "$profile" ] || profile="$BECOME/all"
  39
  40 file="${TMPDIR:-/tmp}/$USER.become.$user.$RANDOM.$$"
  41 umask=$(builtin umask -p)
  42 builtin umask 077
  43 if exec 3>"$file" && exec <"$file" && rm "$file"; then
  44   builtin $umask
  45   echo >&3 "cd"
  46   echo >&3 "PROFILE_HOME='$HOME'"
  47   if [ -n "$PRINCIPAL" ]; then
  48     echo >&3 "PRINCIPAL='$PRINCIPAL'"
  49     if [ $kerberos = 1 ]; then
  50       ccname=$(klist 2>/dev/null | sed -n 's/^Ticket cache: FILE://p')
  51       if [ -f "$ccname" ]; then
  52         openssl=$(find_working openssl)
  53         if [ -n "$openssl" ]; then
  54           echo >&3 "KRB5OPENSSL='$openssl'"
  55           echo >&3 "KRB5BASE64='$($openssl enc -a -in $ccname)'"
  56         fi
  57       fi
  58     fi
  59   fi
  60   if [ -n "$DISPLAY" -a -n "$COOKIE" ]; then
  61     echo >&3 "xauth add $COOKIE"
  62   else
  63     echo >&3 "unset DISPLAY"
  64   fi
  65 else
  66   exit 111
  67 fi
  68
  69 echo >&3 ". $HOME/.bash_profile"
  70 [ -f "$BECOME/all" ] && cat >&3 2>/dev/null "$BECOME/all"
  71 [ -f "$BECOME/$user" ] && cat >&3 2>/dev/null "$BECOME/$user"
  72 echo >&3 2>/dev/null "cd - &>/dev/null"
  73
  74 exec 3>&-
  75 dir=$(dirname "$0")
  76 [ "$dir" = "." ] && dir="$PWD"
  77 exec sudo -H -u "$user" "$dir/became"
  78 exit 111