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Re: weird problem -- path interpretted/eval'd as numeric expression


From: Linda Walsh
Subject: Re: weird problem -- path interpretted/eval'd as numeric expression
Date: Fri, 29 Mar 2013 00:41:46 -0700
User-agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.8.1.24) Gecko/20100228 Lightning/0.9 Thunderbird/2.0.0.24 Mnenhy/0.7.6.666


Dan Douglas wrote:
> Can you whittle this down to the smallest reproducer and post a stand-alone 
> synthetic testcase with sample input data that fails?
----
        If I had a clue how to do that, I would, that's why I mentioned
that that **NORMALLY** it works fine.

        include was designed to search the path for functions that
are relative paths.  While the normal sourcepath allows searching for
filenames on the search path, I don't believe (please correct if I am wrong
and this works now, as it would make life much simpler) that the PATH will
be searched if you give it something like:

source lib/Util/sourcefile.shh

I can work around things in lib by putting 'lib' in my path, but
for things not at the first level...

exporting arrays (and Hashes) was something to make USE of, not a goal.
I wanted to be able to store arbitrary pathnames and the only way to
do that easily is to have them in arrays, since you can't use '\000'
as a separator.  I had similar requirements for group names -- I wanted
to test for group membership by name, so I can use Hashes to test
if something 'should' work (actual file permissions will decide security),
but the HASH'ed group tests are to give messages about needing to be
in such and such a group or whether or not to go ahead and try.   Attempting
to falsify the _GROUPS_ array would only lead to ugly error messages. ;-)

echo ${_GROUPS_[Remote Desktop Users]}
555
echo ${_GROUPS_[Domain Admins]}
512


I also use similar methods for propagating aliases like
int=declare\ -i
array=declare\ -a
sub=function
my=declare
etc...

'int' and 'sub' are the most useful ones...

> 
> If the goal is simulating "exported arrays", there are other methods that 
> would probably work out better.
---
        Well, if that isn't the goal, but the above are goals, do your methods
apply equally well?  Without NULL as a separator, arrays are the only way to
store things without lots of quoting, but they are very difficult to use ...
Try pulling out a groupid from a groupname without a hash...it is doable, but
not nearly so simply.

I've *lived* with the reported bug for at least several months, because I 
couldn't
figure out why it failed there but not elsewhere.

It only *fails* when including 'needroot.shh'...

But these two work:
> cd /tmp
> include stdalias.shh          #include file or lib/file are generally 
> equivalent
> include lib/stdlib.shh
> include Util/urlparts.shh     # but this one - Util is a subdir of 'lib' 
> (i.e. not in path)
> echo address@hidden  ## keeps track of what has been included so a subsequent 
> include won't reinclude
/home/law/bin/lib/stdlib.shh /home/law/bin/lib/Util/urlparts.shh
/home/law/bin/lib/stdalias.shh
#i.e.:
> echo ${_INC[stdalias.shh]}
/home/law/bin/lib/stdalias.shh


The calling script CAN be simple:
#!/bin/bash
include Util/needroot.shh
whoami

> tryroot
./tryroot: line 7: Util/needroot.shh: syntax error: invalid arithmetic operator
(error token is ".shh")
law
--- or if I do include lib/Util/needroot.shh I get the div by 0:
> cat zroot
#!/bin/bash
include lib/Util/needroot.shh
whoami
> zroot
./zroot: line 7: lib/Util/needroot.shh: division by 0 (error token is
"/needroot.shh")
law

----
Util/needroot.shh works when sourced:

> cat >do_root
#!/bin/bash
source ~/lib/Util/needroot.shh
whoami

Ishtar:tmp> +x do_root
Ishtar:tmp> do_root
root
----
Oddly, it happens w/needroot even when it doesn't re-execute itself (i.e. 
already
running as root!)  (but only if it needs to access it via the PATH --
if I'm in a dir like bin, and needroot is in bin/lib/Util/needroot.shh
then it works!

needroot.shh:
#!/bin/bash
shift
declare -xi _needroot+=1
sudo="$(type -P sudo 2>/dev/null)"
if [[ $sudo == "" || ! -e $sudo ]]; then
  ((_needroot<2)) && echo "warning: sudo not found, executing as normal 
user..." >&2
  exit 0
else
  # echo "UID=$UID, EUID=$EUID"
  if ((EUID)); then
    ((_needroot<2)) &&  exec $(eval echo sudo "$0" "$@")
    echo "Need root: Fatal error" >&2
    exit -1
  fi
fi
((1))
-------------------  function include:
declare -A _INC
export _INC
function include {
  [[ $1 ]] || return 1
  local fnc="$1"
  [[ $PATH != ${_SPATH:-} || address@hidden -lt 1 ]] && {
    unset _FPATH
    local -xa _FPATH=( $(IFS=:;echo $PATH) )
    export _SPATH="$PATH"
  }
# function seems to exit here when including needroot when it's not given via a
relative name
# i.e. would need to find it off of the PATH

  if [[ -z ${_INC["${fnc:-}"]:-}  ]]; then
    local pw
    for pw in "address@hidden"; do
      [[ ${pw:0-1:1} != / ]] && pw+='/'
      local fn="${pw}${fnc}"
      if [[ -r $fn  || -r $fn.shh && fn="$fn.shh"  ]]; then
        source "$fn"  || {
          stat=$?
          echo "Error: include of \"$fnc\" did not return 0 status"
          return $stat
        }
        _INC["$fnc"]="$fn"
        return 0
      fi
    done
    echo "Cannot find \"$fnc\" in \"$PATH\"" >&2
    exit 2
  fi
}
export -f include
----------------------------
Those are the basic
parts....
















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