#!/bin/bash
# validator--Checks to ensure that the PATH contains only valid directories, 
#   then checks that all environment variables are valid.
#   Looks at SHELL, HOME, PATH, EDITOR, MAIL, and PAGER.

setglobal errors = '0'

source ../1/library.sh # which contains Script #1, the in_path() function

proc validate
{
  setglobal varname = $1    
  setglobal varvalue = $2
  
  if test ! -z $varvalue  {
    if test $(varvalue%${varvalue#?}) = "/"  {
      if test ! -x $varvalue  {
        echo "** $varname set to $varvalue, but I cannot find executable."
        sh-expr ' errors++ '
      }
    } else {
      if in_path $varvalue $PATH  { 
        echo "** $varname set to $varvalue, but I cannot find it in PATH."
        setglobal errors = $shExpr(' $errors + 1 ')
      }
    } 
  }
}

# BEGIN MAIN SCRIPT
# =================

if test ! -x $(SHELL:?"Cannot proceed without SHELL being defined.")  {
  echo "** SHELL set to $SHELL, but I cannot find that executable."
  setglobal errors = $shExpr(' $errors + 1 ')
}

if test ! -d $(HOME:?"You need to have your HOME set to your home directory")
{
  echo "** HOME set to $HOME, but it's not a directory."
  setglobal errors = $shExpr(' $errors + 1 ')
}

# Our first interesting test: Are all the paths in PATH valid?

setglobal oldIFS = $IFS; setglobal IFS = '":'"     # IFS is the field separator. We'll change to ':'

for directory in [$PATH]
{
  if test ! -d $directory  {
      echo "** PATH contains invalid directory $directory"
      setglobal errors = $shExpr(' $errors + 1 ')
  }
}

setglobal IFS = $oldIFS             # restore value for rest of script

# The following variables should each be a fully qualified path, 
#   but they may be either undefined or a progname. Add additional 
#   variables as necessary for your site and user community.

validate "EDITOR" $EDITOR
validate "MAILER" $MAILER
validate "PAGER"  $PAGER

# And, finally, a different ending depending on whether errors > 0

if test $errors -gt 0  {
  echo "Errors encountered. Please notify sysadmin for help."
} else {
  echo "Your environment checks out fine."
}

exit 0