Re: Redirecting $TEMP or a certain directory to /tmp

[Lee Rothstein <lee at veritech dot com>]

Thorsten Kampe wrote:

> Thomas Wiedmann (Tue, 12 Jan 2010 08:24:57 +0100) wrote

>> how can in Cygwin the directory, which is in Windows configured as 
$TEMP, or
>> a certain other directory, be redirected to /tmp?

> man mount

My approach is different, I solve the problem on the Windows side for all
apps, Cygwin, or Windows.

My system is Visa 64b; others use a slightly different "menu"
sequence, but:

 Control Panel -> System -> Advanced system settings ->
   Environment Variables -> System Variables ->
   TEMP == %TMPDIR%
 and  ...                                    ->
   TMPDIR ==  c:\_0\tmp
and (because some pseudo *nix apps for Windows use $TMP, instead of $TMPDIR:
      ...                                    ->
   TMP == %TMPDIR%

(since Cygwin root on my system is at 'c:\_0')

My approach means that both Windows and Cygwin apps use the same
directory for temporary files. This means I only have to "clean up"
or search in one temporary directory.


I also use the attached script, 'tmpdir', when I'm using the temporary
directory with unknown *NIX configs.

It has it's own help (-h|--help).

As always, YMMV.
#!/bin/bash

# tmpdir: resilient TeMPorary Directory Inquisition Reporter

# 'tmpdir' "finds" a master temporary directory (MTD) -- the directory in
# which temporary files and directories of an appication's session are
# stored. With certain options, it will create the directory.

# By Lee Rothstein, 2009-02-07 11:56

ProgName=tmpdir
Version="0.4.0"
UpDate="2009-05-10"

HelpEm () {
    less << !!!EOF!!!
NAME

  tmpdir - *resilient* TeMPorary Directory Intantiator/Reporter

DESCRIPTION

  'tmpdir' "finds" a master temporary directory (MTD) -- the
  directory in which temporary files and directories of an
  application's session are stored. With certain options it will
  create (recursively, i.e., 'mkdir - p') the directory.

  In most GNU, UNIX, BSD, Linux, Cygwin and Posix systems, the
  MTD is either /tmp, or the directory referenced by $TMPDIR. In
  Cygwin, a likely additional possibility is the directory
  referenced by $TEMP.

  Normally, 'tmpdir' will be used by another script. Practical
  uses for this utility include:

  * If you're writing scripts for unknown users and are unsure of
    their environment, 'tmpdir' might be one element of a
    "foolproof" approach. Alas, however, fools are such clever
    creatures; witness, George W. Bush (or, at least, George W.
    Bush with Karl Rove's help).

  * Creating a more private MTD for a specific application or
    session.

 SYNOPSIS

   tmpdir -h
   tmpdir [ [-c] [-f TEMPDIRECTORY] [-l TEMPDIRECTORY] ]

 OPTIONS

   Each option is mutually exclusive of the others.  (That is,
   only one can be used per invocation of 'tmpdir'.) Every option
   besides '-h' requires TEMPDIRECTORY.  Any option must be
   specified before a TEMPDIRECTORY is provided.

   -h | --help -- Help -- Provide this help. Take no other
         actions. Exit code = '99'. 'tmpdir' does not use nor
         check for any other arguments, when '-h', or '--help' is
         specified.

         Note: no other "long option names are supported."

   -c -- Create a specified temporary directory. Abort if
         directory already exists.

   -f -- Force -- Force the use of the specified directory
         whether or not it pre-exists. (This option will not
         delete a file that prevents the creation of a directory
         by the same name. Ergo, even "The Force" is limited in
         its power ;-) )

   -l -- Last resort -- Go through the normal sequence of
         temporary directory investigation.  If none is found,
         try TEMPDIRECTORY, if it doesn't exist create it
         (recursively, i.e., 'mkdir -p').

   With the exception of help, long option syntax is not
   supported!

 USAGE

   Rules:

   * Almost any name acceptable to the file system is acceptable
     as TEMPDIRECTORY, except one beginning with a dash.  This is
     done for four reasons:

     > It makes option sanity checking easier.
     > The user is very likely making a mistake about options
       usage.
     > It's very bad form. MTDs beginning with '-' would likely
       cause problems later when 'tmpdir' was used in a script.
     > If you don't like it, you can always change it, it's just
       a script.

   * Success is finding or creating an MTD -- return value == 0.

   * Whenever it succeeds, and returns '0', it 'stdouts' the name
     of that directory.

   * Failure for any operational reason returns '1'. 'stdout' is
     null. Failure means there is not a temporary directory, of
     any kind, to be found.

     The help option exits with a "return code" of '99'. Errors
     in command line specification also return 90 series numbers.
     Help is directed to 'stdout' piped through 'less'.

   * Error messages are limited in size and always directed to
     'stderr'.

   * Directories are only created if one of the options is used.

   * '-c' will create a directory (recursively, i.e., 'mkdir -p')
     if one doesn't exist, but will fail if the specified
     directory already exists.

   * '-f' will use the pre-existing specified directory and
      create (recursively, i.e., 'mkdir -p') and use it
      otherwise.

   * '-l' will cause 'tmpdir' to go through all the remaining
     steps, using TEMPDIRECTORY only as a penultimate
     alternative; creating it (recursively, i.e., 'mkdir -p') and
     using it, only if it doesn't already exist.

   * Barring an MTD command line specification, 'tmpdir' will
     search for valid directories, in order, in the following
     "name space", until it achieve a success, or exhausts all
     alternatives:

     > '\$TMPDIR', if defined, and exists.
     > '/tmp'
     > '\$TEMP', if defined and it exists.

   * If step last step (just above) fails, and '-l' has been
     specified, then and only then will TEMPDIRECTORY be
     tried/created (recursively, i.e., 'mkdir -p').

   * Any path name, of the temporary directory, is sent to
     'stdout' in Posix format.

 Typically, 'tmpdir' will be used in an execute in place command
 where the output of 'tmpdir will assigned to an environment
 variable, or files will be stored.

 EXAMPLES

 --
   # 1
   # Here, the user can select an alternative directory for the MTD
   # by removing the '#' from the following 2nd 'TmpDirArgs=' line

   ...
   TmpdirArgs=""
   #TmpdirArgs="-f Tmp.dir"
   ...
   TmpPath=\$(tmpdir \$TmpdirArgs)
   ...
   any_command> \$TmpPath/\$0-\$\$
   ...
 --
   # 2
   # Here if all of \$TMPDIR, '/tmp', and \$TEMP , don't exist 'tmpdir'
   # will create  an MTD, '/tmp'

   ...
   TmpPath="\$(tmpdir -l /tmp)"
   ...
 --
   # 3
   # Even if '\$TMPDIR' is defined and exists, '/tmp' will be used
   # whether or not it existed prior to the 'tmpdir'

   ...
   TmpPath="\$(tmpdir -f /tmp)"
   if [[ "\$?" -ne 0 || "\$TmpPath" == "" ]] ; them
     echo "\$(basename \$0): Execution aborted."
     echo "  Temporary directory not found"
     exit 3
   fi
   ...
 --
   # 4
   # The user has decided that s/he wishes to save the results in
   # a subdirectory of the current directory, named '_Saves'. The
   # '-c' option plus the if test guarantee, that past saved data
   # will not be overwritten.

   ...
   # date +%Y-%m-%d+%H-%M-%S
   #   e.g., '2010-12-20+16-52' for 20 Dec 2010, 4:52 PM
   date1=\$(date +%Y-%m-%d+%H-%M-%S)
   TmpPath="\$(tmpdir -c _Saves/\$date1)"
   if [[ "\$?" -ne 0 || "\$TmpPath" == "" ]] ; them
     echo "\$(basename \$0): Execution aborted."
     echo "  A new temporary directory could not be created."
     exit 3
   fi
   ...
 --

 VERSION

   ${Version}; ${UpDate}.

 BUGS AND LIMITATIONS

   Currently there is no way to set the permissions on a created
   MST, inside of 'tmpdir'.

!!!EOF!!!
    exit 99
}

# GraceExit: GRACEfully stdout the temporary directory path (in Posix format)
#            & 'EXIT 0'
GraceExit () {
    echo "$(cygpath -u $1)"
    exit 0
}

# WarnAbort: Issue WARNing ($2) to stderr
#         "Issue" null temporary directory path to stdout
#         ABort & exit with code $1
WarnAbort () {
  {
    echo "${ProgName}: ** error **:"
    echo "$2"|fmt -50|xargs --max-lines=1 echo " "
    echo ""
    echo "  For help, type \"${ProgName} -h\""
    exit $1
  } 1>&2
}

if [[ "$1" == "-h" || "$1" == "--help" ]] ; then HelpEm ; fi

case $# in
  0) Option=""
     TmpPath=""
     ;;
  1) Option=""
     if [[ "$1" =~ -[-a-zA-Z0-9] ]] ; then
       WarnAbort 96 "Directory ('$1') starts with '-', or option misused."
     fi
     TmpPath="$1"
     ;;
  2) Option="$1"
     TmpPath="$2"
     case "$Option" in
       "-c"|"-f"|"-l")
         ;;
       *) WarnAbort 97 "Unrecognized option -- '$Option'!"
         ;;
     esac
     ;;
  *) WarnAbort 98 "Can't have more than 2 arguments"
     ;;
esac

# Has an MTD been specified, but we're not using the "Last Resort" option?
if [[ -n "$TmpPath" && "$Option" != "-l" ]] ; then

    # Does the specified MTD exist?
    if [[ -e "$TmpPath" ]] ; then

        # Is the specified MTD really a directory?
        if [[ -d "$TmpPath" ]] ; then

            # No option, or the Force option?
            if [[ -z "$Option" || "$Option" == "-f" ]] ; then
                GraceExit "$TmpPath"

            # Is "Create" option (which only uses the MTD, if it can create it) operative?
            elif [[ "$Option" == "-c" ]] ; then
                WarnAbort 1 "Specified dir exists, but must create; can't do with '-c' option."
            fi

        # Specified MTD exists and is not a directory
        else
            WarnAbort 1 "$TmpPath exists but is not a directory."
        fi

    # Specified MTD does not exist. Can we create it?
    elif [[ "$Option" == "-c" || "$Option" == "-f" ]] ; then
        mkdir -p $TmpPath
        MkDirCode="$?"

        # Did we successfully create the MTD?
        if [[ "$MkDirCode" == 0 ]] ; then
            GraceExit "$TmpPath"

        # Attempt to create the MTD failed.
        else
            WarnAbort 1 "Couldn't 'mkdir -p $TmpPath' . 'mkdir' exit code was '$MkdirCode' ."
        fi

    fi

    # For the situation of a path being specified and the possibility of
    # creating an MTD (except for the Last resort option), all other
    # alternatives have either succeeded or failed and in either case
    # exited.

    WarnAbort 1 "Specified path -- $TmpPath -- doesn't exist!"

# No options or Last resort (-l) option. Ergo, must try to find existing MTD.
# Does the variable "$TMPDIR" exist; does it reference a directory?
elif [[ -n "$TMPDIR" && -d "$TMPDIR" ]] ; then
    GraceExit "$TMPDIR"

# How about good ol' '/tmp'?
elif [[ -d /tmp ]] ; then
    GraceExit "/tmp"

# Windows $TEMP directory?
elif [[ -n "$TEMP" && -d "$(cygpath -u $TEMP)" ]] ; then
    GraceExit "$TEMP"

# We're down to the Last resort?
elif [[ "$Option" == "-l" ]] ; then

    # Does the specified MTD already exist?
    if [[ -e "$TmpPath" ]] ; then

         # If it's a directory use it.
         if [[ -d "$TmpPath" ]] ; then
             GraceExit "$TmpPath"

         # No luck, here, either
         else
             WarnAbort 1 "Last resort temp path--'$TmpPath'--exists & is not dir!"
         fi

    # Try creating the directory
    else
        mkdir -p $TmpPath
        MkDirCode="$?"
        if [[ "$MkDirCode" == 0 ]] ; then
            GraceExit "$TmpPath"
        else
            WarnAbort 1 "Couldn't 'mkdir -p $TmpPath'. 'mkdir' exit code was $MkdirCode."
        fi

    fi

else

    WarnAbort 1 "No viable temporary directory could be found!"
    # At this point, either the author of this script, or the invoker needs a brain implant. ;-)

fi

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple