#!/bin/sh
######################################################################
#
#   aliasme
#
#   Program allows a user to add e-mail aliases
#   for him or herself without bugging the sysadmin
#
#   REQ FILES & FACILITIES
#     cron
#     sendmail
#     /etc/mail/aliasme.conf
#     /etc/mail/aliases
#     /etc/mail/aliasme/ (dir)
#     /etc/passwd
#     "alias" group
#     aliasme script
#
#   FILES USED WITHIN:
#       /etc/mail/aliasme/useraliases.tmp       validated user aliases
#       /tmp/aliases.tmp                        saved system aliases
#       /etc/mail/aliasme/aliases.bak.$DATE     backed up aliases file
#
#   C. Geigner - (c)2003, This program may be distributed under the 
#   LGPL. Read the LGPL here: http://www.gnu.org/copyleft/lesser.html
#   
#########################################################################
VER="aliasme v0.1-4 beta - By Chuck Geigner (c) 2003"
USAGE="Usage: aliasme [-k]\
-k runs aliasme in check-only mode (does not update).\
When run as root, the -k flag will validate all .aliases files in home dirs\
belonging to users in the \"alias\" group."

CHK_ALIAS()
{
 SUCCESS=1
 # if were not root, then we must not be running GEN_LIST, which would in turn make
 # AUSER undefined. So we set AUSER to the username of who called us.
 if [ ${USER} != "root" ]; then
   AUSER=${USER}
 fi
 echo "Checking aliases for user ${AUSER}:"
 if [ -s /home/$AUSER/.aliases ]; then
   for ENTRY in `cat /home/$AUSER/.aliases`
   do
     # check for illegal chars in aliases
     echo "${ENTRY}" | grep "[^0-9a-z_-]" 2> /dev/null
     if [ $? -eq 0 ]; then
       SUCCESS=0
       echo "The ${AUSER} alias \"${ENTRY}\" contains illegal or uppercase letters" 
       if [ ${MODE} = "usercheck" ]; then
         echo "Please edit your .aliases file to correct this conflict."
       fi
     fi
     # check for conflicts in aliases
     grep -v "${AUSER}$" /etc/mail/aliases | grep "^${ENTRY}:"
     if [ $? -eq 0 ]; then
       SUCCESS=0
       echo "The ${AUSER} defined alias \"${ENTRY}\" is already in use by another user."
       if [ ${MODE} = "usercheck" ]; then
         echo "Please edit your .aliases file to correct this conflict."
       fi
     elif [ $? -gt 1 ]; then
       echo "File problem encountered with /etc/mail/aliases."
       echo "Please check file and re-try (or contact admin)."
       exit
     fi
     # check for conflicts in system passwd file
     grep "^${ENTRY}:" /etc/passwd
     if [ $? -eq 0 ]; then
       SUCCESS=0
       echo "\"${ENTRY}\" is already an existing username."
       if [ ${MODE} = "usercheck" ]; then
         echo "Please edit your .aliases file to correct this conflict."
       fi
     elif [ $? -gt 1 ]; then
       echo "File problem encountered with /etc/passwd."
       SUCCESS=0 
       if [ ${MODE} = "usercheck" ]; then
         echo "Please check file and re-try (or contact admin)."
         exit
       fi
     fi
     # check for conflicts in aliases already in tmp file
     if [ ${MODE} = "admin" ]; then
       if [ -s /etc/mail/aliasme/useraliases.tmp ]; then
         grep "^${ENTRY}:" /etc/mail/aliasme/useraliases.tmp
         if [ $? -eq 0 ]; then
           SUCCESS=0
           echo "\"${ENTRY}\" is already an existing alias."
         elif [ $? -gt 1 ]; then
           echo "File problem encountered with /etc/mail/aliasme/useraliases.tmp."
           SUCCESS=0
           exit
         fi
       fi
     fi 
     # note all-ok if no probs with alias choices, set go-ahead tag for write to aliases_restr
   done
 else
   echo "The alias file /home/${AUSER}/.aliases is missing or empty."
   SUCCESS=0
   if [ ${MODE} = "usercheck" ]; then
     exit
   fi
 fi
 if [ ${SUCCESS} -eq 1 ]; then
   echo "All aliases for ${AUSER} checked and valid."
 fi 
}


GEN_LIST()
{
 if [ ${USER} = "root" ]; then
   if [ ! -d /etc/mail/aliasme/ ]; then
     mkdir /etc/mail/aliasme/
   fi
   # reset this file if it exists and > 0
   if [ -s /etc/mail/aliasme/useraliases.tmp ]; then
     cat /dev/null > /etc/mail/aliasme/useraliases.tmp
   fi
   # generate a list of alias users from those found in the alias group
   # and then run validity checks and add valids to the tmp file.
   for AUSER in `grep "^alias:" /etc/group |\
                 awk -F: '{print $4}'|\
                 awk -F, '{for (i=1;i<=NF;i++) print $i}'`
   do
     CHK_ALIAS;
     if [ ${SUCCESS} -eq 1 -a ${MODE} = "admin" ]; then
       echo "##aliasme ${AUSER}" >> /etc/mail/aliasme/useraliases.tmp
       for LINES in `cat /home/$AUSER/.aliases`
       do
         echo "${LINES}:   ${AUSER}" >> /etc/mail/aliasme/useraliases.tmp
       done
       echo "##aliasme--end" >> /etc/mail/aliasme/useraliases.tmp
     fi
   done
   if [ ${MODE} = "admincheck" ]; then
      rm /etc/mail/aliasme/useraliases.tmp    #If in check-only mode, 
      exit;                                   #No need to stick around, we're done
   fi
   BAK="/etc/mail/aliasme/aliases.bak.`date +%b%d-%H%M`"
   cp /etc/mail/aliases ${BAK}                # back up orig aliases file by date/time
                                              # let's see if we already have entries
   grep "##aliasme" /etc/mail/aliases > /dev/null
   if [ $? -eq 0 ]; then                      #yup, we have some
                                              #NOTE: All aliasme entries begin with "##aliasme"
                                              #and end with "##aliasme--end"
     # Munge munge munge. Hopefully it all goes back together, eh? ;)
     # NEXT: Preserve the current non-aliasme aliases!!!
     SNIPSTART=`awk '$1 ~ /##aliasme/{print NR}' /etc/mail/aliases |head -1`   #line number of start
     SNIPEND=`awk '$1 ~ /##aliasme--end/{print NR}' /etc/mail/aliases |tail -1` #line num of last entry
     LINECT=`awk 'END{print NR}' /etc/mail/aliases`
     if [ ${LINECT} -gt 2     -a \
          ${SNIPSTART} != ""  -a \
          ${SNIPEND}   != ""  -a \
          ${SNIPEND} -gt ${SNIPSTART} ]; then
       SNIPSTART=`expr ${SNIPSTART} - 1`      #actually we need to stop at the line before...
       awk 'NR==1,NR=='${SNIPSTART} /etc/mail/aliases > /tmp/aliases.tmp  
                                              #dump all non-aliasme entries fm line 1 to start
       if [ ${LINECT} -gt ${SNIPEND} ]; then  #if there's more non-aliasme entries at EOF
         SNIPEND=`expr ${SNIPEND} + 1`        #...resume on the line after
         awk 'NR=='${SNIPEND}',NR=='${LINECT} /etc/mail/aliases >> /tmp/aliases.tmp
                                              #then dump all non-aliasme entries from end to EOF
       fi
     else
       echo "Not enough lines in aliases file to save!"
     fi
   else
     cat /etc/mail/aliases > /tmp/aliases.tmp  #no prev aliasme entries found, so dump the whole file
   fi
   # Put system aliases and user aliases back into the aliases file and rebuild.
   if [ -s /etc/mail/aliasme/useraliases.tmp ]; then
     cat /tmp/aliases.tmp /etc/mail/aliasme/useraliases.tmp > /etc/mail/aliases
   else   # no user aliases defined so...
     cat /tmp/aliases.tmp > /etc/mail/aliases
   fi
   if [ -f ${BAK} ]; then
     SUM1=`sum ${BAK} |awk '{print $1}'`
   else
     SUM1=0
   fi
   SUM2=`sum /etc/mail/aliases | awk '{print $1}'`
   if [ ${SUM1} -eq ${SUM2} ]; then
     echo "No changes occured. Exiting."
     rm -f ${BAK} #no need to backup or process if the files are the same
   else  #build the new aliases db
     echo "Updating aliases database..".
     newaliases
     echo "...done."
   fi
   rm -f /etc/mail/aliasme/useraliases.tmp
   rm -f /tmp/aliashead.tmp
   #signal end of process regardless of errors
 else
   echo "Only the root user may update the aliases table."
   exit
 fi
}

# $ aliasme
if [ ${USER} != "root" ]; then
  MODE="usercheck"
  CHK_ALIAS;
#aliasme -k
else
  if [ $# -ge 2 ]; then
    if [ $1 -eq "-k" ]; then
      MODE="admincheck"
    else
      echo ${USAGE}; 
      exit
    fi
  else
    MODE="admin"
  fi
  GEN_LIST;
fi