xref: /openbsd/gnu/usr.bin/perl/cpan/File-Temp/lib/File/Temp.pm (revision 771fbea0)

package File::Temp; # git description: v0.2308-7-g3bb4d88
# ABSTRACT: return name and handle of a temporary file safely

our $VERSION = '0.2309';

#pod =begin :__INTERNALS
#pod
#pod =head1 PORTABILITY
#pod
#pod This section is at the top in order to provide easier access to
#pod porters.  It is not expected to be rendered by a standard pod
#pod formatting tool. Please skip straight to the SYNOPSIS section if you
#pod are not trying to port this module to a new platform.
#pod
#pod This module is designed to be portable across operating systems and it
#pod currently supports Unix, VMS, DOS, OS/2, Windows and Mac OS
#pod (Classic). When porting to a new OS there are generally three main
#pod issues that have to be solved:
#pod
#pod =over 4
#pod
#pod =item *
#pod
#pod Can the OS unlink an open file? If it can not then the
#pod C<_can_unlink_opened_file> method should be modified.
#pod
#pod =item *
#pod
#pod Are the return values from C<stat> reliable? By default all the
#pod return values from C<stat> are compared when unlinking a temporary
#pod file using the filename and the handle. Operating systems other than
#pod unix do not always have valid entries in all fields. If utility function
#pod C<File::Temp::unlink0> fails then the C<stat> comparison should be
#pod modified accordingly.
#pod
#pod =item *
#pod
#pod Security. Systems that can not support a test for the sticky bit
#pod on a directory can not use the MEDIUM and HIGH security tests.
#pod The C<_can_do_level> method should be modified accordingly.
#pod
#pod =back
#pod
#pod =end :__INTERNALS
#pod
#pod =head1 SYNOPSIS
#pod
#pod   use File::Temp qw/ tempfile tempdir /;
#pod
#pod   $fh = tempfile();
#pod   ($fh, $filename) = tempfile();
#pod
#pod   ($fh, $filename) = tempfile( $template, DIR => $dir);
#pod   ($fh, $filename) = tempfile( $template, SUFFIX => '.dat');
#pod   ($fh, $filename) = tempfile( $template, TMPDIR => 1 );
#pod
#pod   binmode( $fh, ":utf8" );
#pod
#pod   $dir = tempdir( CLEANUP => 1 );
#pod   ($fh, $filename) = tempfile( DIR => $dir );
#pod
#pod Object interface:
#pod
#pod   require File::Temp;
#pod   use File::Temp ();
#pod   use File::Temp qw/ :seekable /;
#pod
#pod   $fh = File::Temp->new();
#pod   $fname = $fh->filename;
#pod
#pod   $fh = File::Temp->new(TEMPLATE => $template);
#pod   $fname = $fh->filename;
#pod
#pod   $tmp = File::Temp->new( UNLINK => 0, SUFFIX => '.dat' );
#pod   print $tmp "Some data\n";
#pod   print "Filename is $tmp\n";
#pod   $tmp->seek( 0, SEEK_END );
#pod
#pod   $dir = File::Temp->newdir(); # CLEANUP => 1 by default
#pod
#pod The following interfaces are provided for compatibility with
#pod existing APIs. They should not be used in new code.
#pod
#pod MkTemp family:
#pod
#pod   use File::Temp qw/ :mktemp  /;
#pod
#pod   ($fh, $file) = mkstemp( "tmpfileXXXXX" );
#pod   ($fh, $file) = mkstemps( "tmpfileXXXXXX", $suffix);
#pod
#pod   $tmpdir = mkdtemp( $template );
#pod
#pod   $unopened_file = mktemp( $template );
#pod
#pod POSIX functions:
#pod
#pod   use File::Temp qw/ :POSIX /;
#pod
#pod   $file = tmpnam();
#pod   $fh = tmpfile();
#pod
#pod   ($fh, $file) = tmpnam();
#pod
#pod Compatibility functions:
#pod
#pod   $unopened_file = File::Temp::tempnam( $dir, $pfx );
#pod
#pod =head1 DESCRIPTION
#pod
#pod C<File::Temp> can be used to create and open temporary files in a safe
#pod way.  There is both a function interface and an object-oriented
#pod interface.  The File::Temp constructor or the tempfile() function can
#pod be used to return the name and the open filehandle of a temporary
#pod file.  The tempdir() function can be used to create a temporary
#pod directory.
#pod
#pod The security aspect of temporary file creation is emphasized such that
#pod a filehandle and filename are returned together.  This helps guarantee
#pod that a race condition can not occur where the temporary file is
#pod created by another process between checking for the existence of the
#pod file and its opening.  Additional security levels are provided to
#pod check, for example, that the sticky bit is set on world writable
#pod directories.  See L<"safe_level"> for more information.
#pod
#pod For compatibility with popular C library functions, Perl implementations of
#pod the mkstemp() family of functions are provided. These are, mkstemp(),
#pod mkstemps(), mkdtemp() and mktemp().
#pod
#pod Additionally, implementations of the standard L<POSIX|POSIX>
#pod tmpnam() and tmpfile() functions are provided if required.
#pod
#pod Implementations of mktemp(), tmpnam(), and tempnam() are provided,
#pod but should be used with caution since they return only a filename
#pod that was valid when function was called, so cannot guarantee
#pod that the file will not exist by the time the caller opens the filename.
#pod
#pod Filehandles returned by these functions support the seekable methods.
#pod
#pod =cut

# Toolchain targets v5.8.1, but we'll try to support back to v5.6 anyway.
# It might be possible to make this v5.5, but many v5.6isms are creeping
# into the code and tests.
use 5.006;
use strict;
use Carp;
use File::Spec 0.8;
use Cwd ();
use File::Path 2.06 qw/ rmtree /;
use Fcntl 1.03;
use IO::Seekable;               # For SEEK_*
use Errno;
use Scalar::Util 'refaddr';
require VMS::Stdio if $^O eq 'VMS';

# pre-emptively load Carp::Heavy. If we don't when we run out of file
# handles and attempt to call croak() we get an error message telling
# us that Carp::Heavy won't load rather than an error telling us we
# have run out of file handles. We either preload croak() or we
# switch the calls to croak from _gettemp() to use die.
eval { require Carp::Heavy; };

# Need the Symbol package if we are running older perl
require Symbol if $] < 5.006;

### For the OO interface
use parent 0.221 qw/ IO::Handle IO::Seekable /;
use overload '""' => "STRINGIFY", '0+' => "NUMIFY",
  fallback => 1;

our $DEBUG = 0;
our $KEEP_ALL = 0;

# We are exporting functions

use Exporter 5.57 'import';   # 5.57 lets us import 'import'

# Export list - to allow fine tuning of export table

our @EXPORT_OK = qw{
                 tempfile
                 tempdir
                 tmpnam
                 tmpfile
                 mktemp
                 mkstemp
                 mkstemps
                 mkdtemp
                 unlink0
                 cleanup
                 SEEK_SET
                 SEEK_CUR
                 SEEK_END
             };

# Groups of functions for export

our %EXPORT_TAGS = (
                'POSIX' => [qw/ tmpnam tmpfile /],
                'mktemp' => [qw/ mktemp mkstemp mkstemps mkdtemp/],
                'seekable' => [qw/ SEEK_SET SEEK_CUR SEEK_END /],
               );

# add contents of these tags to @EXPORT
Exporter::export_tags('POSIX','mktemp','seekable');

# This is a list of characters that can be used in random filenames

my @CHARS = (qw/ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
                 a b c d e f g h i j k l m n o p q r s t u v w x y z
                 0 1 2 3 4 5 6 7 8 9 _
               /);

# Maximum number of tries to make a temp file before failing

use constant MAX_TRIES => 1000;

# Minimum number of X characters that should be in a template
use constant MINX => 4;

# Default template when no template supplied

use constant TEMPXXX => 'X' x 10;

# Constants for the security level

use constant STANDARD => 0;
use constant MEDIUM   => 1;
use constant HIGH     => 2;

# OPENFLAGS. If we defined the flag to use with Sysopen here this gives
# us an optimisation when many temporary files are requested

my $OPENFLAGS = O_CREAT | O_EXCL | O_RDWR;
my $LOCKFLAG;

unless ($^O eq 'MacOS') {
  for my $oflag (qw/ NOFOLLOW BINARY LARGEFILE NOINHERIT /) {
    my ($bit, $func) = (0, "Fcntl::O_" . $oflag);
    no strict 'refs';
    $OPENFLAGS |= $bit if eval {
      # Make sure that redefined die handlers do not cause problems
      # e.g. CGI::Carp
      local $SIG{__DIE__} = sub {};
      local $SIG{__WARN__} = sub {};
      $bit = &$func();
      1;
    };
  }
  # Special case O_EXLOCK
  $LOCKFLAG = eval {
    local $SIG{__DIE__} = sub {};
    local $SIG{__WARN__} = sub {};
    &Fcntl::O_EXLOCK();
  };
}

# On some systems the O_TEMPORARY flag can be used to tell the OS
# to automatically remove the file when it is closed. This is fine
# in most cases but not if tempfile is called with UNLINK=>0 and
# the filename is requested -- in the case where the filename is to
# be passed to another routine. This happens on windows. We overcome
# this by using a second open flags variable

my $OPENTEMPFLAGS = $OPENFLAGS;
unless ($^O eq 'MacOS') {
  for my $oflag (qw/ TEMPORARY /) {
    my ($bit, $func) = (0, "Fcntl::O_" . $oflag);
    local($@);
    no strict 'refs';
    $OPENTEMPFLAGS |= $bit if eval {
      # Make sure that redefined die handlers do not cause problems
      # e.g. CGI::Carp
      local $SIG{__DIE__} = sub {};
      local $SIG{__WARN__} = sub {};
      $bit = &$func();
      1;
    };
  }
}

# Private hash tracking which files have been created by each process id via the OO interface
my %FILES_CREATED_BY_OBJECT;

# INTERNAL ROUTINES - not to be used outside of package

# Generic routine for getting a temporary filename
# modelled on OpenBSD _gettemp() in mktemp.c

# The template must contain X's that are to be replaced
# with the random values

#  Arguments:

#  TEMPLATE   - string containing the XXXXX's that is converted
#           to a random filename and opened if required

# Optionally, a hash can also be supplied containing specific options
#   "open" => if true open the temp file, else just return the name
#             default is 0
#   "mkdir"=> if true, we are creating a temp directory rather than tempfile
#             default is 0
#   "suffixlen" => number of characters at end of PATH to be ignored.
#                  default is 0.
#   "unlink_on_close" => indicates that, if possible,  the OS should remove
#                        the file as soon as it is closed. Usually indicates
#                        use of the O_TEMPORARY flag to sysopen.
#                        Usually irrelevant on unix
#   "use_exlock" => Indicates that O_EXLOCK should be used. Default is false.

# Optionally a reference to a scalar can be passed into the function
# On error this will be used to store the reason for the error
#   "ErrStr"  => \$errstr

# "open" and "mkdir" can not both be true
# "unlink_on_close" is not used when "mkdir" is true.

# The default options are equivalent to mktemp().

# Returns:
#   filehandle - open file handle (if called with doopen=1, else undef)
#   temp name  - name of the temp file or directory

# For example:
#   ($fh, $name) = _gettemp($template, "open" => 1);

# for the current version, failures are associated with
# stored in an error string and returned to give the reason whilst debugging
# This routine is not called by any external function
sub _gettemp {

  croak 'Usage: ($fh, $name) = _gettemp($template, OPTIONS);'
    unless scalar(@_) >= 1;

  # the internal error string - expect it to be overridden
  # Need this in case the caller decides not to supply us a value
  # need an anonymous scalar
  my $tempErrStr;

  # Default options
  my %options = (
                 "open" => 0,
                 "mkdir" => 0,
                 "suffixlen" => 0,
                 "unlink_on_close" => 0,
                 "use_exlock" => 0,
                 "ErrStr" => \$tempErrStr,
                );

  # Read the template
  my $template = shift;
  if (ref($template)) {
    # Use a warning here since we have not yet merged ErrStr
    carp "File::Temp::_gettemp: template must not be a reference";
    return ();
  }

  # Check that the number of entries on stack are even
  if (scalar(@_) % 2 != 0) {
    # Use a warning here since we have not yet merged ErrStr
    carp "File::Temp::_gettemp: Must have even number of options";
    return ();
  }

  # Read the options and merge with defaults
  %options = (%options, @_)  if @_;

  # Make sure the error string is set to undef
  ${$options{ErrStr}} = undef;

  # Can not open the file and make a directory in a single call
  if ($options{"open"} && $options{"mkdir"}) {
    ${$options{ErrStr}} = "doopen and domkdir can not both be true\n";
    return ();
  }

  # Find the start of the end of the  Xs (position of last X)
  # Substr starts from 0
  my $start = length($template) - 1 - $options{"suffixlen"};

  # Check that we have at least MINX x X (e.g. 'XXXX") at the end of the string
  # (taking suffixlen into account). Any fewer is insecure.

  # Do it using substr - no reason to use a pattern match since
  # we know where we are looking and what we are looking for

  if (substr($template, $start - MINX + 1, MINX) ne 'X' x MINX) {
    ${$options{ErrStr}} = "The template must end with at least ".
      MINX . " 'X' characters\n";
    return ();
  }

  # Replace all the X at the end of the substring with a
  # random character or just all the XX at the end of a full string.
  # Do it as an if, since the suffix adjusts which section to replace
  # and suffixlen=0 returns nothing if used in the substr directly
  # and generate a full path from the template

  my $path = _replace_XX($template, $options{"suffixlen"});


  # Split the path into constituent parts - eventually we need to check
  # whether the directory exists
  # We need to know whether we are making a temp directory
  # or a tempfile

  my ($volume, $directories, $file);
  my $parent;                   # parent directory
  if ($options{"mkdir"}) {
    # There is no filename at the end
    ($volume, $directories, $file) = File::Spec->splitpath( $path, 1);

    # The parent is then $directories without the last directory
    # Split the directory and put it back together again
    my @dirs = File::Spec->splitdir($directories);

    # If @dirs only has one entry (i.e. the directory template) that means
    # we are in the current directory
    if ($#dirs == 0) {
      $parent = File::Spec->curdir;
    } else {

      if ($^O eq 'VMS') {     # need volume to avoid relative dir spec
        $parent = File::Spec->catdir($volume, @dirs[0..$#dirs-1]);
        $parent = 'sys$disk:[]' if $parent eq '';
      } else {

        # Put it back together without the last one
        $parent = File::Spec->catdir(@dirs[0..$#dirs-1]);

        # ...and attach the volume (no filename)
        $parent = File::Spec->catpath($volume, $parent, '');
      }

    }

  } else {

    # Get rid of the last filename (use File::Basename for this?)
    ($volume, $directories, $file) = File::Spec->splitpath( $path );

    # Join up without the file part
    $parent = File::Spec->catpath($volume,$directories,'');

    # If $parent is empty replace with curdir
    $parent = File::Spec->curdir
      unless $directories ne '';

  }

  # Check that the parent directories exist
  # Do this even for the case where we are simply returning a name
  # not a file -- no point returning a name that includes a directory
  # that does not exist or is not writable

  unless (-e $parent) {
    ${$options{ErrStr}} = "Parent directory ($parent) does not exist";
    return ();
  }
  unless (-d $parent) {
    ${$options{ErrStr}} = "Parent directory ($parent) is not a directory";
    return ();
  }

  # Check the stickiness of the directory and chown giveaway if required
  # If the directory is world writable the sticky bit
  # must be set

  if (File::Temp->safe_level == MEDIUM) {
    my $safeerr;
    unless (_is_safe($parent,\$safeerr)) {
      ${$options{ErrStr}} = "Parent directory ($parent) is not safe ($safeerr)";
      return ();
    }
  } elsif (File::Temp->safe_level == HIGH) {
    my $safeerr;
    unless (_is_verysafe($parent, \$safeerr)) {
      ${$options{ErrStr}} = "Parent directory ($parent) is not safe ($safeerr)";
      return ();
    }
  }


  # Now try MAX_TRIES time to open the file
  for (my $i = 0; $i < MAX_TRIES; $i++) {

    # Try to open the file if requested
    if ($options{"open"}) {
      my $fh;

      # If we are running before perl5.6.0 we can not auto-vivify
      if ($] < 5.006) {
        $fh = &Symbol::gensym;
      }

      # Try to make sure this will be marked close-on-exec
      # XXX: Win32 doesn't respect this, nor the proper fcntl,
      #      but may have O_NOINHERIT. This may or may not be in Fcntl.
      local $^F = 2;

      # Attempt to open the file
      my $open_success = undef;
      if ( $^O eq 'VMS' and $options{"unlink_on_close"} && !$KEEP_ALL) {
        # make it auto delete on close by setting FAB$V_DLT bit
        $fh = VMS::Stdio::vmssysopen($path, $OPENFLAGS, 0600, 'fop=dlt');
        $open_success = $fh;
      } else {
        my $flags = ( ($options{"unlink_on_close"} && !$KEEP_ALL) ?
                      $OPENTEMPFLAGS :
                      $OPENFLAGS );
        $flags |= $LOCKFLAG if (defined $LOCKFLAG && $options{use_exlock});
        $open_success = sysopen($fh, $path, $flags, 0600);
      }
      if ( $open_success ) {

        # in case of odd umask force rw
        chmod(0600, $path);

        # Opened successfully - return file handle and name
        return ($fh, $path);

      } else {

        # Error opening file - abort with error
        # if the reason was anything but EEXIST
        unless ($!{EEXIST}) {
          ${$options{ErrStr}} = "Could not create temp file $path: $!";
          return ();
        }

        # Loop round for another try

      }
    } elsif ($options{"mkdir"}) {

      # Open the temp directory
      if (mkdir( $path, 0700)) {
        # in case of odd umask
        chmod(0700, $path);

        return undef, $path;
      } else {

        # Abort with error if the reason for failure was anything
        # except EEXIST
        unless ($!{EEXIST}) {
          ${$options{ErrStr}} = "Could not create directory $path: $!";
          return ();
        }

        # Loop round for another try

      }

    } else {

      # Return true if the file can not be found
      # Directory has been checked previously

      return (undef, $path) unless -e $path;

      # Try again until MAX_TRIES

    }

    # Did not successfully open the tempfile/dir
    # so try again with a different set of random letters
    # No point in trying to increment unless we have only
    # 1 X say and the randomness could come up with the same
    # file MAX_TRIES in a row.

    # Store current attempt - in principle this implies that the
    # 3rd time around the open attempt that the first temp file
    # name could be generated again. Probably should store each
    # attempt and make sure that none are repeated

    my $original = $path;
    my $counter = 0;            # Stop infinite loop
    my $MAX_GUESS = 50;

    do {

      # Generate new name from original template
      $path = _replace_XX($template, $options{"suffixlen"});

      $counter++;

    } until ($path ne $original || $counter > $MAX_GUESS);

    # Check for out of control looping
    if ($counter > $MAX_GUESS) {
      ${$options{ErrStr}} = "Tried to get a new temp name different to the previous value $MAX_GUESS times.\nSomething wrong with template?? ($template)";
      return ();
    }

  }

  # If we get here, we have run out of tries
  ${ $options{ErrStr} } = "Have exceeded the maximum number of attempts ("
    . MAX_TRIES . ") to open temp file/dir";

  return ();

}

# Internal routine to replace the XXXX... with random characters
# This has to be done by _gettemp() every time it fails to
# open a temp file/dir

# Arguments:  $template (the template with XXX),
#             $ignore   (number of characters at end to ignore)

# Returns:    modified template

sub _replace_XX {

  croak 'Usage: _replace_XX($template, $ignore)'
    unless scalar(@_) == 2;

  my ($path, $ignore) = @_;

  # Do it as an if, since the suffix adjusts which section to replace
  # and suffixlen=0 returns nothing if used in the substr directly
  # Alternatively, could simply set $ignore to length($path)-1
  # Don't want to always use substr when not required though.
  my $end = ( $] >= 5.006 ? "\\z" : "\\Z" );

  if ($ignore) {
    substr($path, 0, - $ignore) =~ s/X(?=X*$end)/$CHARS[ int( rand( @CHARS ) ) ]/ge;
  } else {
    $path =~ s/X(?=X*$end)/$CHARS[ int( rand( @CHARS ) ) ]/ge;
  }
  return $path;
}

# Internal routine to force a temp file to be writable after
# it is created so that we can unlink it. Windows seems to occasionally
# force a file to be readonly when written to certain temp locations
sub _force_writable {
  my $file = shift;
  chmod 0600, $file;
}


# internal routine to check to see if the directory is safe
# First checks to see if the directory is not owned by the
# current user or root. Then checks to see if anyone else
# can write to the directory and if so, checks to see if
# it has the sticky bit set

# Will not work on systems that do not support sticky bit

#Args:  directory path to check
#       Optionally: reference to scalar to contain error message
# Returns true if the path is safe and false otherwise.
# Returns undef if can not even run stat() on the path

# This routine based on version written by Tom Christiansen

# Presumably, by the time we actually attempt to create the
# file or directory in this directory, it may not be safe
# anymore... Have to run _is_safe directly after the open.

sub _is_safe {

  my $path = shift;
  my $err_ref = shift;

  # Stat path
  my @info = stat($path);
  unless (scalar(@info)) {
    $$err_ref = "stat(path) returned no values";
    return 0;
  }
  ;
  return 1 if $^O eq 'VMS';     # owner delete control at file level

  # Check to see whether owner is neither superuser (or a system uid) nor me
  # Use the effective uid from the $> variable
  # UID is in [4]
  if ($info[4] > File::Temp->top_system_uid() && $info[4] != $>) {

    Carp::cluck(sprintf "uid=$info[4] topuid=%s euid=$> path='$path'",
                File::Temp->top_system_uid());

    $$err_ref = "Directory owned neither by root nor the current user"
      if ref($err_ref);
    return 0;
  }

  # check whether group or other can write file
  # use 066 to detect either reading or writing
  # use 022 to check writability
  # Do it with S_IWOTH and S_IWGRP for portability (maybe)
  # mode is in info[2]
  if (($info[2] & &Fcntl::S_IWGRP) ||  # Is group writable?
      ($info[2] & &Fcntl::S_IWOTH) ) { # Is world writable?
    # Must be a directory
    unless (-d $path) {
      $$err_ref = "Path ($path) is not a directory"
        if ref($err_ref);
      return 0;
    }
    # Must have sticky bit set
    unless (-k $path) {
      $$err_ref = "Sticky bit not set on $path when dir is group|world writable"
        if ref($err_ref);
      return 0;
    }
  }

  return 1;
}

# Internal routine to check whether a directory is safe
# for temp files. Safer than _is_safe since it checks for
# the possibility of chown giveaway and if that is a possibility
# checks each directory in the path to see if it is safe (with _is_safe)

# If _PC_CHOWN_RESTRICTED is not set, does the full test of each
# directory anyway.

# Takes optional second arg as scalar ref to error reason

sub _is_verysafe {

  # Need POSIX - but only want to bother if really necessary due to overhead
  require POSIX;

  my $path = shift;
  print "_is_verysafe testing $path\n" if $DEBUG;
  return 1 if $^O eq 'VMS';     # owner delete control at file level

  my $err_ref = shift;

  # Should Get the value of _PC_CHOWN_RESTRICTED if it is defined
  # and If it is not there do the extensive test
  local($@);
  my $chown_restricted;
  $chown_restricted = &POSIX::_PC_CHOWN_RESTRICTED()
    if eval { &POSIX::_PC_CHOWN_RESTRICTED(); 1};

  # If chown_resticted is set to some value we should test it
  if (defined $chown_restricted) {

    # Return if the current directory is safe
    return _is_safe($path,$err_ref) if POSIX::sysconf( $chown_restricted );

  }

  # To reach this point either, the _PC_CHOWN_RESTRICTED symbol
  # was not available or the symbol was there but chown giveaway
  # is allowed. Either way, we now have to test the entire tree for
  # safety.

  # Convert path to an absolute directory if required
  unless (File::Spec->file_name_is_absolute($path)) {
    $path = File::Spec->rel2abs($path);
  }

  # Split directory into components - assume no file
  my ($volume, $directories, undef) = File::Spec->splitpath( $path, 1);

  # Slightly less efficient than having a function in File::Spec
  # to chop off the end of a directory or even a function that
  # can handle ../ in a directory tree
  # Sometimes splitdir() returns a blank at the end
  # so we will probably check the bottom directory twice in some cases
  my @dirs = File::Spec->splitdir($directories);

  # Concatenate one less directory each time around
  foreach my $pos (0.. $#dirs) {
    # Get a directory name
    my $dir = File::Spec->catpath($volume,
                                  File::Spec->catdir(@dirs[0.. $#dirs - $pos]),
                                  ''
                                 );

    print "TESTING DIR $dir\n" if $DEBUG;

    # Check the directory
    return 0 unless _is_safe($dir,$err_ref);

  }

  return 1;
}



# internal routine to determine whether unlink works on this
# platform for files that are currently open.
# Returns true if we can, false otherwise.

# Currently WinNT, OS/2 and VMS can not unlink an opened file
# On VMS this is because the O_EXCL flag is used to open the
# temporary file. Currently I do not know enough about the issues
# on VMS to decide whether O_EXCL is a requirement.

sub _can_unlink_opened_file {

  if (grep { $^O eq $_ } qw/MSWin32 os2 VMS dos MacOS haiku/) {
    return 0;
  } else {
    return 1;
  }

}

# internal routine to decide which security levels are allowed
# see safe_level() for more information on this

# Controls whether the supplied security level is allowed

#   $cando = _can_do_level( $level )

sub _can_do_level {

  # Get security level
  my $level = shift;

  # Always have to be able to do STANDARD
  return 1 if $level == STANDARD;

  # Currently, the systems that can do HIGH or MEDIUM are identical
  if ( $^O eq 'MSWin32' || $^O eq 'os2' || $^O eq 'cygwin' || $^O eq 'dos' || $^O eq 'MacOS' || $^O eq 'mpeix') {
    return 0;
  } else {
    return 1;
  }

}

# This routine sets up a deferred unlinking of a specified
# filename and filehandle. It is used in the following cases:
#  - Called by unlink0 if an opened file can not be unlinked
#  - Called by tempfile() if files are to be removed on shutdown
#  - Called by tempdir() if directories are to be removed on shutdown

# Arguments:
#   _deferred_unlink( $fh, $fname, $isdir );
#
#   - filehandle (so that it can be explicitly closed if open
#   - filename   (the thing we want to remove)
#   - isdir      (flag to indicate that we are being given a directory)
#                 [and hence no filehandle]

# Status is not referred to since all the magic is done with an END block

{
  # Will set up two lexical variables to contain all the files to be
  # removed. One array for files, another for directories They will
  # only exist in this block.

  #  This means we only have to set up a single END block to remove
  #  all files.

  # in order to prevent child processes inadvertently deleting the parent
  # temp files we use a hash to store the temp files and directories
  # created by a particular process id.

  # %files_to_unlink contains values that are references to an array of
  # array references containing the filehandle and filename associated with
  # the temp file.
  my (%files_to_unlink, %dirs_to_unlink);

  # Set up an end block to use these arrays
  END {
    local($., $@, $!, $^E, $?);
    cleanup(at_exit => 1);
  }

  # Cleanup function. Always triggered on END (with at_exit => 1) but
  # can be invoked manually.
  sub cleanup {
    my %h = @_;
    my $at_exit = delete $h{at_exit};
    $at_exit = 0 if not defined $at_exit;
    { my @k = sort keys %h; die "unrecognized parameters: @k" if @k }

    if (!$KEEP_ALL) {
      # Files
      my @files = (exists $files_to_unlink{$$} ?
                   @{ $files_to_unlink{$$} } : () );
      foreach my $file (@files) {
        # close the filehandle without checking its state
        # in order to make real sure that this is closed
        # if its already closed then I don't care about the answer
        # probably a better way to do this
        close($file->[0]);      # file handle is [0]

        if (-f $file->[1]) {       # file name is [1]
          _force_writable( $file->[1] ); # for windows
          unlink $file->[1] or warn "Error removing ".$file->[1];
        }
      }
      # Dirs
      my @dirs = (exists $dirs_to_unlink{$$} ?
                  @{ $dirs_to_unlink{$$} } : () );
      my ($cwd, $cwd_to_remove);
      foreach my $dir (@dirs) {
        if (-d $dir) {
          # Some versions of rmtree will abort if you attempt to remove
          # the directory you are sitting in. For automatic cleanup
          # at program exit, we avoid this by chdir()ing out of the way
          # first. If not at program exit, it's best not to mess with the
          # current directory, so just let it fail with a warning.
          if ($at_exit) {
            $cwd = Cwd::abs_path(File::Spec->curdir) if not defined $cwd;
            my $abs = Cwd::abs_path($dir);
            if ($abs eq $cwd) {
              $cwd_to_remove = $dir;
              next;
            }
          }
          eval { rmtree($dir, $DEBUG, 0); };
          warn $@ if ($@ && $^W);
        }
      }

      if (defined $cwd_to_remove) {
        # We do need to clean up the current directory, and everything
        # else is done, so get out of there and remove it.
        chdir $cwd_to_remove or die "cannot chdir to $cwd_to_remove: $!";
        my $updir = File::Spec->updir;
        chdir $updir or die "cannot chdir to $updir: $!";
        eval { rmtree($cwd_to_remove, $DEBUG, 0); };
        warn $@ if ($@ && $^W);
      }

      # clear the arrays
      @{ $files_to_unlink{$$} } = ()
        if exists $files_to_unlink{$$};
      @{ $dirs_to_unlink{$$} } = ()
        if exists $dirs_to_unlink{$$};
    }
  }


  # This is the sub called to register a file for deferred unlinking
  # This could simply store the input parameters and defer everything
  # until the END block. For now we do a bit of checking at this
  # point in order to make sure that (1) we have a file/dir to delete
  # and (2) we have been called with the correct arguments.
  sub _deferred_unlink {

    croak 'Usage:  _deferred_unlink($fh, $fname, $isdir)'
      unless scalar(@_) == 3;

    my ($fh, $fname, $isdir) = @_;

    warn "Setting up deferred removal of $fname\n"
      if $DEBUG;

    # make sure we save the absolute path for later cleanup
    # OK to untaint because we only ever use this internally
    # as a file path, never interpolating into the shell
    $fname = Cwd::abs_path($fname);
    ($fname) = $fname =~ /^(.*)$/;

    # If we have a directory, check that it is a directory
    if ($isdir) {

      if (-d $fname) {

        # Directory exists so store it
        # first on VMS turn []foo into [.foo] for rmtree
        $fname = VMS::Filespec::vmspath($fname) if $^O eq 'VMS';
        $dirs_to_unlink{$$} = []
          unless exists $dirs_to_unlink{$$};
        push (@{ $dirs_to_unlink{$$} }, $fname);

      } else {
        carp "Request to remove directory $fname could not be completed since it does not exist!\n" if $^W;
      }

    } else {

      if (-f $fname) {

        # file exists so store handle and name for later removal
        $files_to_unlink{$$} = []
          unless exists $files_to_unlink{$$};
        push(@{ $files_to_unlink{$$} }, [$fh, $fname]);

      } else {
        carp "Request to remove file $fname could not be completed since it is not there!\n" if $^W;
      }

    }

  }


}

# normalize argument keys to upper case and do consistent handling
# of leading template vs TEMPLATE
sub _parse_args {
  my $leading_template = (scalar(@_) % 2 == 1 ? shift(@_) : '' );
  my %args = @_;
  %args = map { uc($_), $args{$_} } keys %args;

  # template (store it in an array so that it will
  # disappear from the arg list of tempfile)
  my @template = (
    exists $args{TEMPLATE}  ? $args{TEMPLATE} :
    $leading_template       ? $leading_template : ()
  );
  delete $args{TEMPLATE};

  return( \@template, \%args );
}

#pod =head1 OBJECT-ORIENTED INTERFACE
#pod
#pod This is the primary interface for interacting with
#pod C<File::Temp>. Using the OO interface a temporary file can be created
#pod when the object is constructed and the file can be removed when the
#pod object is no longer required.
#pod
#pod Note that there is no method to obtain the filehandle from the
#pod C<File::Temp> object. The object itself acts as a filehandle.  The object
#pod isa C<IO::Handle> and isa C<IO::Seekable> so all those methods are
#pod available.
#pod
#pod Also, the object is configured such that it stringifies to the name of the
#pod temporary file and so can be compared to a filename directly.  It numifies
#pod to the C<refaddr> the same as other handles and so can be compared to other
#pod handles with C<==>.
#pod
#pod     $fh eq $filename       # as a string
#pod     $fh != \*STDOUT        # as a number
#pod
#pod Available since 0.14.
#pod
#pod =over 4
#pod
#pod =item B<new>
#pod
#pod Create a temporary file object.
#pod
#pod   my $tmp = File::Temp->new();
#pod
#pod by default the object is constructed as if C<tempfile>
#pod was called without options, but with the additional behaviour
#pod that the temporary file is removed by the object destructor
#pod if UNLINK is set to true (the default).
#pod
#pod Supported arguments are the same as for C<tempfile>: UNLINK
#pod (defaulting to true), DIR, EXLOCK and SUFFIX. Additionally, the filename
#pod template is specified using the TEMPLATE option. The OPEN option
#pod is not supported (the file is always opened).
#pod
#pod  $tmp = File::Temp->new( TEMPLATE => 'tempXXXXX',
#pod                         DIR => 'mydir',
#pod                         SUFFIX => '.dat');
#pod
#pod Arguments are case insensitive.
#pod
#pod Can call croak() if an error occurs.
#pod
#pod Available since 0.14.
#pod
#pod TEMPLATE available since 0.23
#pod
#pod =cut

sub new {
  my $proto = shift;
  my $class = ref($proto) || $proto;

  my ($maybe_template, $args) = _parse_args(@_);

  # see if they are unlinking (defaulting to yes)
  my $unlink = (exists $args->{UNLINK} ? $args->{UNLINK} : 1 );
  delete $args->{UNLINK};

  # Protect OPEN
  delete $args->{OPEN};

  # Open the file and retain file handle and file name
  my ($fh, $path) = tempfile( @$maybe_template, %$args );

  print "Tmp: $fh - $path\n" if $DEBUG;

  # Store the filename in the scalar slot
  ${*$fh} = $path;

  # Cache the filename by pid so that the destructor can decide whether to remove it
  $FILES_CREATED_BY_OBJECT{$$}{$path} = 1;

  # Store unlink information in hash slot (plus other constructor info)
  %{*$fh} = %$args;

  # create the object
  bless $fh, $class;

  # final method-based configuration
  $fh->unlink_on_destroy( $unlink );

  return $fh;
}

#pod =item B<newdir>
#pod
#pod Create a temporary directory using an object oriented interface.
#pod
#pod   $dir = File::Temp->newdir();
#pod
#pod By default the directory is deleted when the object goes out of scope.
#pod
#pod Supports the same options as the C<tempdir> function. Note that directories
#pod created with this method default to CLEANUP => 1.
#pod
#pod   $dir = File::Temp->newdir( $template, %options );
#pod
#pod A template may be specified either with a leading template or
#pod with a TEMPLATE argument.
#pod
#pod Available since 0.19.
#pod
#pod TEMPLATE available since 0.23.
#pod
#pod =cut

sub newdir {
  my $self = shift;

  my ($maybe_template, $args) = _parse_args(@_);

  # handle CLEANUP without passing CLEANUP to tempdir
  my $cleanup = (exists $args->{CLEANUP} ? $args->{CLEANUP} : 1 );
  delete $args->{CLEANUP};

  my $tempdir = tempdir( @$maybe_template, %$args);

  # get a safe absolute path for cleanup, just like
  # happens in _deferred_unlink
  my $real_dir = Cwd::abs_path( $tempdir );
  ($real_dir) = $real_dir =~ /^(.*)$/;

  return bless { DIRNAME => $tempdir,
                 REALNAME => $real_dir,
                 CLEANUP => $cleanup,
                 LAUNCHPID => $$,
               }, "File::Temp::Dir";
}

#pod =item B<filename>
#pod
#pod Return the name of the temporary file associated with this object
#pod (if the object was created using the "new" constructor).
#pod
#pod   $filename = $tmp->filename;
#pod
#pod This method is called automatically when the object is used as
#pod a string.
#pod
#pod Current API available since 0.14
#pod
#pod =cut

sub filename {
  my $self = shift;
  return ${*$self};
}

sub STRINGIFY {
  my $self = shift;
  return $self->filename;
}

# For reference, can't use '0+'=>\&Scalar::Util::refaddr directly because
# refaddr() demands one parameter only, whereas overload.pm calls with three
# even for unary operations like '0+'.
sub NUMIFY {
  return refaddr($_[0]);
}

#pod =item B<dirname>
#pod
#pod Return the name of the temporary directory associated with this
#pod object (if the object was created using the "newdir" constructor).
#pod
#pod   $dirname = $tmpdir->dirname;
#pod
#pod This method is called automatically when the object is used in string context.
#pod
#pod =item B<unlink_on_destroy>
#pod
#pod Control whether the file is unlinked when the object goes out of scope.
#pod The file is removed if this value is true and $KEEP_ALL is not.
#pod
#pod  $fh->unlink_on_destroy( 1 );
#pod
#pod Default is for the file to be removed.
#pod
#pod Current API available since 0.15
#pod
#pod =cut

sub unlink_on_destroy {
  my $self = shift;
  if (@_) {
    ${*$self}{UNLINK} = shift;
  }
  return ${*$self}{UNLINK};
}

#pod =item B<DESTROY>
#pod
#pod When the object goes out of scope, the destructor is called. This
#pod destructor will attempt to unlink the file (using L<unlink1|"unlink1">)
#pod if the constructor was called with UNLINK set to 1 (the default state
#pod if UNLINK is not specified).
#pod
#pod No error is given if the unlink fails.
#pod
#pod If the object has been passed to a child process during a fork, the
#pod file will be deleted when the object goes out of scope in the parent.
#pod
#pod For a temporary directory object the directory will be removed unless
#pod the CLEANUP argument was used in the constructor (and set to false) or
#pod C<unlink_on_destroy> was modified after creation.  Note that if a temp
#pod directory is your current directory, it cannot be removed - a warning
#pod will be given in this case.  C<chdir()> out of the directory before
#pod letting the object go out of scope.
#pod
#pod If the global variable $KEEP_ALL is true, the file or directory
#pod will not be removed.
#pod
#pod =cut

sub DESTROY {
  local($., $@, $!, $^E, $?);
  my $self = shift;

  # Make sure we always remove the file from the global hash
  # on destruction. This prevents the hash from growing uncontrollably
  # and post-destruction there is no reason to know about the file.
  my $file = $self->filename;
  my $was_created_by_proc;
  if (exists $FILES_CREATED_BY_OBJECT{$$}{$file}) {
    $was_created_by_proc = 1;
    delete $FILES_CREATED_BY_OBJECT{$$}{$file};
  }

  if (${*$self}{UNLINK} && !$KEEP_ALL) {
    print "# --------->   Unlinking $self\n" if $DEBUG;

    # only delete if this process created it
    return unless $was_created_by_proc;

    # The unlink1 may fail if the file has been closed
    # by the caller. This leaves us with the decision
    # of whether to refuse to remove the file or simply
    # do an unlink without test. Seems to be silly
    # to do this when we are trying to be careful
    # about security
    _force_writable( $file ); # for windows
    unlink1( $self, $file )
      or unlink($file);
  }
}

#pod =back
#pod
#pod =head1 FUNCTIONS
#pod
#pod This section describes the recommended interface for generating
#pod temporary files and directories.
#pod
#pod =over 4
#pod
#pod =item B<tempfile>
#pod
#pod This is the basic function to generate temporary files.
#pod The behaviour of the file can be changed using various options:
#pod
#pod   $fh = tempfile();
#pod   ($fh, $filename) = tempfile();
#pod
#pod Create a temporary file in  the directory specified for temporary
#pod files, as specified by the tmpdir() function in L<File::Spec>.
#pod
#pod   ($fh, $filename) = tempfile($template);
#pod
#pod Create a temporary file in the current directory using the supplied
#pod template.  Trailing `X' characters are replaced with random letters to
#pod generate the filename.  At least four `X' characters must be present
#pod at the end of the template.
#pod
#pod   ($fh, $filename) = tempfile($template, SUFFIX => $suffix)
#pod
#pod Same as previously, except that a suffix is added to the template
#pod after the `X' translation.  Useful for ensuring that a temporary
#pod filename has a particular extension when needed by other applications.
#pod But see the WARNING at the end.
#pod
#pod   ($fh, $filename) = tempfile($template, DIR => $dir);
#pod
#pod Translates the template as before except that a directory name
#pod is specified.
#pod
#pod   ($fh, $filename) = tempfile($template, TMPDIR => 1);
#pod
#pod Equivalent to specifying a DIR of "File::Spec->tmpdir", writing the file
#pod into the same temporary directory as would be used if no template was
#pod specified at all.
#pod
#pod   ($fh, $filename) = tempfile($template, UNLINK => 1);
#pod
#pod Return the filename and filehandle as before except that the file is
#pod automatically removed when the program exits (dependent on
#pod $KEEP_ALL). Default is for the file to be removed if a file handle is
#pod requested and to be kept if the filename is requested. In a scalar
#pod context (where no filename is returned) the file is always deleted
#pod either (depending on the operating system) on exit or when it is
#pod closed (unless $KEEP_ALL is true when the temp file is created).
#pod
#pod Use the object-oriented interface if fine-grained control of when
#pod a file is removed is required.
#pod
#pod If the template is not specified, a template is always
#pod automatically generated. This temporary file is placed in tmpdir()
#pod (L<File::Spec>) unless a directory is specified explicitly with the
#pod DIR option.
#pod
#pod   $fh = tempfile( DIR => $dir );
#pod
#pod If called in scalar context, only the filehandle is returned and the
#pod file will automatically be deleted when closed on operating systems
#pod that support this (see the description of tmpfile() elsewhere in this
#pod document).  This is the preferred mode of operation, as if you only
#pod have a filehandle, you can never create a race condition by fumbling
#pod with the filename. On systems that can not unlink an open file or can
#pod not mark a file as temporary when it is opened (for example, Windows
#pod NT uses the C<O_TEMPORARY> flag) the file is marked for deletion when
#pod the program ends (equivalent to setting UNLINK to 1). The C<UNLINK>
#pod flag is ignored if present.
#pod
#pod   (undef, $filename) = tempfile($template, OPEN => 0);
#pod
#pod This will return the filename based on the template but
#pod will not open this file.  Cannot be used in conjunction with
#pod UNLINK set to true. Default is to always open the file
#pod to protect from possible race conditions. A warning is issued
#pod if warnings are turned on. Consider using the tmpnam()
#pod and mktemp() functions described elsewhere in this document
#pod if opening the file is not required.
#pod
#pod To open the temporary filehandle with O_EXLOCK (open with exclusive
#pod file lock) use C<< EXLOCK=>1 >>. This is supported only by some
#pod operating systems (most notably BSD derived systems). By default
#pod EXLOCK will be false. Former C<File::Temp> versions set EXLOCK to
#pod true, so to be sure to get an unlocked filehandle also with older
#pod versions, explicitly set C<< EXLOCK=>0 >>.
#pod
#pod   ($fh, $filename) = tempfile($template, EXLOCK => 1);
#pod
#pod Options can be combined as required.
#pod
#pod Will croak() if there is an error.
#pod
#pod Available since 0.05.
#pod
#pod UNLINK flag available since 0.10.
#pod
#pod TMPDIR flag available since 0.19.
#pod
#pod EXLOCK flag available since 0.19.
#pod
#pod =cut

sub tempfile {
  if ( @_ && $_[0] eq 'File::Temp' ) {
      croak "'tempfile' can't be called as a method";
  }
  # Can not check for argument count since we can have any
  # number of args

  # Default options
  my %options = (
                 "DIR"    => undef, # Directory prefix
                 "SUFFIX" => '',    # Template suffix
                 "UNLINK" => 0,     # Do not unlink file on exit
                 "OPEN"   => 1,     # Open file
                 "TMPDIR" => 0, # Place tempfile in tempdir if template specified
                 "EXLOCK" => 0, # Open file with O_EXLOCK
                );

  # Check to see whether we have an odd or even number of arguments
  my ($maybe_template, $args) = _parse_args(@_);
  my $template = @$maybe_template ? $maybe_template->[0] : undef;

  # Read the options and merge with defaults
  %options = (%options, %$args);

  # First decision is whether or not to open the file
  if (! $options{"OPEN"}) {

    warn "tempfile(): temporary filename requested but not opened.\nPossibly unsafe, consider using tempfile() with OPEN set to true\n"
      if $^W;

  }

  if ($options{"DIR"} and $^O eq 'VMS') {

    # on VMS turn []foo into [.foo] for concatenation
    $options{"DIR"} = VMS::Filespec::vmspath($options{"DIR"});
  }

  # Construct the template

  # Have a choice of trying to work around the mkstemp/mktemp/tmpnam etc
  # functions or simply constructing a template and using _gettemp()
  # explicitly. Go for the latter

  # First generate a template if not defined and prefix the directory
  # If no template must prefix the temp directory
  if (defined $template) {
    # End up with current directory if neither DIR not TMPDIR are set
    if ($options{"DIR"}) {

      $template = File::Spec->catfile($options{"DIR"}, $template);

    } elsif ($options{TMPDIR}) {

      $template = File::Spec->catfile(_wrap_file_spec_tmpdir(), $template );

    }

  } else {

    if ($options{"DIR"}) {

      $template = File::Spec->catfile($options{"DIR"}, TEMPXXX);

    } else {

      $template = File::Spec->catfile(_wrap_file_spec_tmpdir(), TEMPXXX);

    }

  }

  # Now add a suffix
  $template .= $options{"SUFFIX"};

  # Determine whether we should tell _gettemp to unlink the file
  # On unix this is irrelevant and can be worked out after the file is
  # opened (simply by unlinking the open filehandle). On Windows or VMS
  # we have to indicate temporary-ness when we open the file. In general
  # we only want a true temporary file if we are returning just the
  # filehandle - if the user wants the filename they probably do not
  # want the file to disappear as soon as they close it (which may be
  # important if they want a child process to use the file)
  # For this reason, tie unlink_on_close to the return context regardless
  # of OS.
  my $unlink_on_close = ( wantarray ? 0 : 1);

  # Create the file
  my ($fh, $path, $errstr);
  croak "Error in tempfile() using template $template: $errstr"
    unless (($fh, $path) = _gettemp($template,
                                    "open" => $options{'OPEN'},
                                    "mkdir"=> 0 ,
                                    "unlink_on_close" => $unlink_on_close,
                                    "suffixlen" => length($options{'SUFFIX'}),
                                    "ErrStr" => \$errstr,
                                    "use_exlock" => $options{EXLOCK},
                                   ) );

  # Set up an exit handler that can do whatever is right for the
  # system. This removes files at exit when requested explicitly or when
  # system is asked to unlink_on_close but is unable to do so because
  # of OS limitations.
  # The latter should be achieved by using a tied filehandle.
  # Do not check return status since this is all done with END blocks.
  _deferred_unlink($fh, $path, 0) if $options{"UNLINK"};

  # Return
  if (wantarray()) {

    if ($options{'OPEN'}) {
      return ($fh, $path);
    } else {
      return (undef, $path);
    }

  } else {

    # Unlink the file. It is up to unlink0 to decide what to do with
    # this (whether to unlink now or to defer until later)
    unlink0($fh, $path) or croak "Error unlinking file $path using unlink0";

    # Return just the filehandle.
    return $fh;
  }


}

# On Windows under taint mode, File::Spec could suggest "C:\" as a tempdir
# which might not be writable.  If that is the case, we fallback to a
# user directory.  See https://rt.cpan.org/Ticket/Display.html?id=60340

{
  my ($alt_tmpdir, $checked);

  sub _wrap_file_spec_tmpdir {
    return File::Spec->tmpdir unless $^O eq "MSWin32" && ${^TAINT};

    if ( $checked ) {
      return $alt_tmpdir ? $alt_tmpdir : File::Spec->tmpdir;
    }

    # probe what File::Spec gives and find a fallback
    my $xxpath = _replace_XX( "X" x 10, 0 );

    # First, see if File::Spec->tmpdir is writable
    my $tmpdir = File::Spec->tmpdir;
    my $testpath = File::Spec->catdir( $tmpdir, $xxpath );
    if (mkdir( $testpath, 0700) ) {
      $checked = 1;
      rmdir $testpath;
      return $tmpdir;
    }

    # Next, see if CSIDL_LOCAL_APPDATA is writable
    require Win32;
    my $local_app = File::Spec->catdir(
      Win32::GetFolderPath( Win32::CSIDL_LOCAL_APPDATA() ), 'Temp'
    );
    $testpath = File::Spec->catdir( $local_app, $xxpath );
    if ( -e $local_app or mkdir( $local_app, 0700 ) ) {
      if (mkdir( $testpath, 0700) ) {
        $checked = 1;
        rmdir $testpath;
        return $alt_tmpdir = $local_app;
      }
    }

    # Can't find something writable
    croak << "HERE";
Couldn't find a writable temp directory in taint mode. Tried:
  $tmpdir
  $local_app

Try setting and untainting the TMPDIR environment variable.
HERE

  }
}

#pod =item B<tempdir>
#pod
#pod This is the recommended interface for creation of temporary
#pod directories.  By default the directory will not be removed on exit
#pod (that is, it won't be temporary; this behaviour can not be changed
#pod because of issues with backwards compatibility). To enable removal
#pod either use the CLEANUP option which will trigger removal on program
#pod exit, or consider using the "newdir" method in the object interface which
#pod will allow the directory to be cleaned up when the object goes out of
#pod scope.
#pod
#pod The behaviour of the function depends on the arguments:
#pod
#pod   $tempdir = tempdir();
#pod
#pod Create a directory in tmpdir() (see L<File::Spec|File::Spec>).
#pod
#pod   $tempdir = tempdir( $template );
#pod
#pod Create a directory from the supplied template. This template is
#pod similar to that described for tempfile(). `X' characters at the end
#pod of the template are replaced with random letters to construct the
#pod directory name. At least four `X' characters must be in the template.
#pod
#pod   $tempdir = tempdir ( DIR => $dir );
#pod
#pod Specifies the directory to use for the temporary directory.
#pod The temporary directory name is derived from an internal template.
#pod
#pod   $tempdir = tempdir ( $template, DIR => $dir );
#pod
#pod Prepend the supplied directory name to the template. The template
#pod should not include parent directory specifications itself. Any parent
#pod directory specifications are removed from the template before
#pod prepending the supplied directory.
#pod
#pod   $tempdir = tempdir ( $template, TMPDIR => 1 );
#pod
#pod Using the supplied template, create the temporary directory in
#pod a standard location for temporary files. Equivalent to doing
#pod
#pod   $tempdir = tempdir ( $template, DIR => File::Spec->tmpdir);
#pod
#pod but shorter. Parent directory specifications are stripped from the
#pod template itself. The C<TMPDIR> option is ignored if C<DIR> is set
#pod explicitly.  Additionally, C<TMPDIR> is implied if neither a template
#pod nor a directory are supplied.
#pod
#pod   $tempdir = tempdir( $template, CLEANUP => 1);
#pod
#pod Create a temporary directory using the supplied template, but
#pod attempt to remove it (and all files inside it) when the program
#pod exits. Note that an attempt will be made to remove all files from
#pod the directory even if they were not created by this module (otherwise
#pod why ask to clean it up?). The directory removal is made with
#pod the rmtree() function from the L<File::Path|File::Path> module.
#pod Of course, if the template is not specified, the temporary directory
#pod will be created in tmpdir() and will also be removed at program exit.
#pod
#pod Will croak() if there is an error.
#pod
#pod Current API available since 0.05.
#pod
#pod =cut

# '

sub tempdir  {
  if ( @_ && $_[0] eq 'File::Temp' ) {
      croak "'tempdir' can't be called as a method";
  }

  # Can not check for argument count since we can have any
  # number of args

  # Default options
  my %options = (
                 "CLEANUP"    => 0, # Remove directory on exit
                 "DIR"        => '', # Root directory
                 "TMPDIR"     => 0,  # Use tempdir with template
                );

  # Check to see whether we have an odd or even number of arguments
  my ($maybe_template, $args) = _parse_args(@_);
  my $template = @$maybe_template ? $maybe_template->[0] : undef;

  # Read the options and merge with defaults
  %options = (%options, %$args);

  # Modify or generate the template

  # Deal with the DIR and TMPDIR options
  if (defined $template) {

    # Need to strip directory path if using DIR or TMPDIR
    if ($options{'TMPDIR'} || $options{'DIR'}) {

      # Strip parent directory from the filename
      #
      # There is no filename at the end
      $template = VMS::Filespec::vmspath($template) if $^O eq 'VMS';
      my ($volume, $directories, undef) = File::Spec->splitpath( $template, 1);

      # Last directory is then our template
      $template = (File::Spec->splitdir($directories))[-1];

      # Prepend the supplied directory or temp dir
      if ($options{"DIR"}) {

        $template = File::Spec->catdir($options{"DIR"}, $template);

      } elsif ($options{TMPDIR}) {

        # Prepend tmpdir
        $template = File::Spec->catdir(_wrap_file_spec_tmpdir(), $template);

      }

    }

  } else {

    if ($options{"DIR"}) {

      $template = File::Spec->catdir($options{"DIR"}, TEMPXXX);

    } else {

      $template = File::Spec->catdir(_wrap_file_spec_tmpdir(), TEMPXXX);

    }

  }

  # Create the directory
  my $tempdir;
  my $suffixlen = 0;
  if ($^O eq 'VMS') {           # dir names can end in delimiters
    $template =~ m/([\.\]:>]+)$/;
    $suffixlen = length($1);
  }
  if ( ($^O eq 'MacOS') && (substr($template, -1) eq ':') ) {
    # dir name has a trailing ':'
    ++$suffixlen;
  }

  my $errstr;
  croak "Error in tempdir() using $template: $errstr"
    unless ((undef, $tempdir) = _gettemp($template,
                                         "open" => 0,
                                         "mkdir"=> 1 ,
                                         "suffixlen" => $suffixlen,
                                         "ErrStr" => \$errstr,
                                        ) );

  # Install exit handler; must be dynamic to get lexical
  if ( $options{'CLEANUP'} && -d $tempdir) {
    _deferred_unlink(undef, $tempdir, 1);
  }

  # Return the dir name
  return $tempdir;

}

#pod =back
#pod
#pod =head1 MKTEMP FUNCTIONS
#pod
#pod The following functions are Perl implementations of the
#pod mktemp() family of temp file generation system calls.
#pod
#pod =over 4
#pod
#pod =item B<mkstemp>
#pod
#pod Given a template, returns a filehandle to the temporary file and the name
#pod of the file.
#pod
#pod   ($fh, $name) = mkstemp( $template );
#pod
#pod In scalar context, just the filehandle is returned.
#pod
#pod The template may be any filename with some number of X's appended
#pod to it, for example F</tmp/temp.XXXX>. The trailing X's are replaced
#pod with unique alphanumeric combinations.
#pod
#pod Will croak() if there is an error.
#pod
#pod Current API available since 0.05.
#pod
#pod =cut



sub mkstemp {

  croak "Usage: mkstemp(template)"
    if scalar(@_) != 1;

  my $template = shift;

  my ($fh, $path, $errstr);
  croak "Error in mkstemp using $template: $errstr"
    unless (($fh, $path) = _gettemp($template,
                                    "open" => 1,
                                    "mkdir"=> 0 ,
                                    "suffixlen" => 0,
                                    "ErrStr" => \$errstr,
                                   ) );

  if (wantarray()) {
    return ($fh, $path);
  } else {
    return $fh;
  }

}


#pod =item B<mkstemps>
#pod
#pod Similar to mkstemp(), except that an extra argument can be supplied
#pod with a suffix to be appended to the template.
#pod
#pod   ($fh, $name) = mkstemps( $template, $suffix );
#pod
#pod For example a template of C<testXXXXXX> and suffix of C<.dat>
#pod would generate a file similar to F<testhGji_w.dat>.
#pod
#pod Returns just the filehandle alone when called in scalar context.
#pod
#pod Will croak() if there is an error.
#pod
#pod Current API available since 0.05.
#pod
#pod =cut

sub mkstemps {

  croak "Usage: mkstemps(template, suffix)"
    if scalar(@_) != 2;


  my $template = shift;
  my $suffix   = shift;

  $template .= $suffix;

  my ($fh, $path, $errstr);
  croak "Error in mkstemps using $template: $errstr"
    unless (($fh, $path) = _gettemp($template,
                                    "open" => 1,
                                    "mkdir"=> 0 ,
                                    "suffixlen" => length($suffix),
                                    "ErrStr" => \$errstr,
                                   ) );

  if (wantarray()) {
    return ($fh, $path);
  } else {
    return $fh;
  }

}

#pod =item B<mkdtemp>
#pod
#pod Create a directory from a template. The template must end in
#pod X's that are replaced by the routine.
#pod
#pod   $tmpdir_name = mkdtemp($template);
#pod
#pod Returns the name of the temporary directory created.
#pod
#pod Directory must be removed by the caller.
#pod
#pod Will croak() if there is an error.
#pod
#pod Current API available since 0.05.
#pod
#pod =cut

#' # for emacs

sub mkdtemp {

  croak "Usage: mkdtemp(template)"
    if scalar(@_) != 1;

  my $template = shift;
  my $suffixlen = 0;
  if ($^O eq 'VMS') {           # dir names can end in delimiters
    $template =~ m/([\.\]:>]+)$/;
    $suffixlen = length($1);
  }
  if ( ($^O eq 'MacOS') && (substr($template, -1) eq ':') ) {
    # dir name has a trailing ':'
    ++$suffixlen;
  }
  my ($junk, $tmpdir, $errstr);
  croak "Error creating temp directory from template $template\: $errstr"
    unless (($junk, $tmpdir) = _gettemp($template,
                                        "open" => 0,
                                        "mkdir"=> 1 ,
                                        "suffixlen" => $suffixlen,
                                        "ErrStr" => \$errstr,
                                       ) );

  return $tmpdir;

}

#pod =item B<mktemp>
#pod
#pod Returns a valid temporary filename but does not guarantee
#pod that the file will not be opened by someone else.
#pod
#pod   $unopened_file = mktemp($template);
#pod
#pod Template is the same as that required by mkstemp().
#pod
#pod Will croak() if there is an error.
#pod
#pod Current API available since 0.05.
#pod
#pod =cut

sub mktemp {

  croak "Usage: mktemp(template)"
    if scalar(@_) != 1;

  my $template = shift;

  my ($tmpname, $junk, $errstr);
  croak "Error getting name to temp file from template $template: $errstr"
    unless (($junk, $tmpname) = _gettemp($template,
                                         "open" => 0,
                                         "mkdir"=> 0 ,
                                         "suffixlen" => 0,
                                         "ErrStr" => \$errstr,
                                        ) );

  return $tmpname;
}

#pod =back
#pod
#pod =head1 POSIX FUNCTIONS
#pod
#pod This section describes the re-implementation of the tmpnam()
#pod and tmpfile() functions described in L<POSIX>
#pod using the mkstemp() from this module.
#pod
#pod Unlike the L<POSIX|POSIX> implementations, the directory used
#pod for the temporary file is not specified in a system include
#pod file (C<P_tmpdir>) but simply depends on the choice of tmpdir()
#pod returned by L<File::Spec|File::Spec>. On some implementations this
#pod location can be set using the C<TMPDIR> environment variable, which
#pod may not be secure.
#pod If this is a problem, simply use mkstemp() and specify a template.
#pod
#pod =over 4
#pod
#pod =item B<tmpnam>
#pod
#pod When called in scalar context, returns the full name (including path)
#pod of a temporary file (uses mktemp()). The only check is that the file does
#pod not already exist, but there is no guarantee that that condition will
#pod continue to apply.
#pod
#pod   $file = tmpnam();
#pod
#pod When called in list context, a filehandle to the open file and
#pod a filename are returned. This is achieved by calling mkstemp()
#pod after constructing a suitable template.
#pod
#pod   ($fh, $file) = tmpnam();
#pod
#pod If possible, this form should be used to prevent possible
#pod race conditions.
#pod
#pod See L<File::Spec/tmpdir> for information on the choice of temporary
#pod directory for a particular operating system.
#pod
#pod Will croak() if there is an error.
#pod
#pod Current API available since 0.05.
#pod
#pod =cut

sub tmpnam {

  # Retrieve the temporary directory name
  my $tmpdir = _wrap_file_spec_tmpdir();

  # XXX I don't know under what circumstances this occurs, -- xdg 2016-04-02
  croak "Error temporary directory is not writable"
    if $tmpdir eq '';

  # Use a ten character template and append to tmpdir
  my $template = File::Spec->catfile($tmpdir, TEMPXXX);

  if (wantarray() ) {
    return mkstemp($template);
  } else {
    return mktemp($template);
  }

}

#pod =item B<tmpfile>
#pod
#pod Returns the filehandle of a temporary file.
#pod
#pod   $fh = tmpfile();
#pod
#pod The file is removed when the filehandle is closed or when the program
#pod exits. No access to the filename is provided.
#pod
#pod If the temporary file can not be created undef is returned.
#pod Currently this command will probably not work when the temporary
#pod directory is on an NFS file system.
#pod
#pod Will croak() if there is an error.
#pod
#pod Available since 0.05.
#pod
#pod Returning undef if unable to create file added in 0.12.
#pod
#pod =cut

sub tmpfile {

  # Simply call tmpnam() in a list context
  my ($fh, $file) = tmpnam();

  # Make sure file is removed when filehandle is closed
  # This will fail on NFS
  unlink0($fh, $file)
    or return undef;

  return $fh;

}

#pod =back
#pod
#pod =head1 ADDITIONAL FUNCTIONS
#pod
#pod These functions are provided for backwards compatibility
#pod with common tempfile generation C library functions.
#pod
#pod They are not exported and must be addressed using the full package
#pod name.
#pod
#pod =over 4
#pod
#pod =item B<tempnam>
#pod
#pod Return the name of a temporary file in the specified directory
#pod using a prefix. The file is guaranteed not to exist at the time
#pod the function was called, but such guarantees are good for one
#pod clock tick only.  Always use the proper form of C<sysopen>
#pod with C<O_CREAT | O_EXCL> if you must open such a filename.
#pod
#pod   $filename = File::Temp::tempnam( $dir, $prefix );
#pod
#pod Equivalent to running mktemp() with $dir/$prefixXXXXXXXX
#pod (using unix file convention as an example)
#pod
#pod Because this function uses mktemp(), it can suffer from race conditions.
#pod
#pod Will croak() if there is an error.
#pod
#pod Current API available since 0.05.
#pod
#pod =cut

sub tempnam {

  croak 'Usage tempnam($dir, $prefix)' unless scalar(@_) == 2;

  my ($dir, $prefix) = @_;

  # Add a string to the prefix
  $prefix .= 'XXXXXXXX';

  # Concatenate the directory to the file
  my $template = File::Spec->catfile($dir, $prefix);

  return mktemp($template);

}

#pod =back
#pod
#pod =head1 UTILITY FUNCTIONS
#pod
#pod Useful functions for dealing with the filehandle and filename.
#pod
#pod =over 4
#pod
#pod =item B<unlink0>
#pod
#pod Given an open filehandle and the associated filename, make a safe
#pod unlink. This is achieved by first checking that the filename and
#pod filehandle initially point to the same file and that the number of
#pod links to the file is 1 (all fields returned by stat() are compared).
#pod Then the filename is unlinked and the filehandle checked once again to
#pod verify that the number of links on that file is now 0.  This is the
#pod closest you can come to making sure that the filename unlinked was the
#pod same as the file whose descriptor you hold.
#pod
#pod   unlink0($fh, $path)
#pod      or die "Error unlinking file $path safely";
#pod
#pod Returns false on error but croaks() if there is a security
#pod anomaly. The filehandle is not closed since on some occasions this is
#pod not required.
#pod
#pod On some platforms, for example Windows NT, it is not possible to
#pod unlink an open file (the file must be closed first). On those
#pod platforms, the actual unlinking is deferred until the program ends and
#pod good status is returned. A check is still performed to make sure that
#pod the filehandle and filename are pointing to the same thing (but not at
#pod the time the end block is executed since the deferred removal may not
#pod have access to the filehandle).
#pod
#pod Additionally, on Windows NT not all the fields returned by stat() can
#pod be compared. For example, the C<dev> and C<rdev> fields seem to be
#pod different.  Also, it seems that the size of the file returned by stat()
#pod does not always agree, with C<stat(FH)> being more accurate than
#pod C<stat(filename)>, presumably because of caching issues even when
#pod using autoflush (this is usually overcome by waiting a while after
#pod writing to the tempfile before attempting to C<unlink0> it).
#pod
#pod Finally, on NFS file systems the link count of the file handle does
#pod not always go to zero immediately after unlinking. Currently, this
#pod command is expected to fail on NFS disks.
#pod
#pod This function is disabled if the global variable $KEEP_ALL is true
#pod and an unlink on open file is supported. If the unlink is to be deferred
#pod to the END block, the file is still registered for removal.
#pod
#pod This function should not be called if you are using the object oriented
#pod interface since the it will interfere with the object destructor deleting
#pod the file.
#pod
#pod Available Since 0.05.
#pod
#pod If can not unlink open file, defer removal until later available since 0.06.
#pod
#pod =cut

sub unlink0 {

  croak 'Usage: unlink0(filehandle, filename)'
    unless scalar(@_) == 2;

  # Read args
  my ($fh, $path) = @_;

  cmpstat($fh, $path) or return 0;

  # attempt remove the file (does not work on some platforms)
  if (_can_unlink_opened_file()) {

    # return early (Without unlink) if we have been instructed to retain files.
    return 1 if $KEEP_ALL;

    # XXX: do *not* call this on a directory; possible race
    #      resulting in recursive removal
    croak "unlink0: $path has become a directory!" if -d $path;
    unlink($path) or return 0;

    # Stat the filehandle
    my @fh = stat $fh;

    print "Link count = $fh[3] \n" if $DEBUG;

    # Make sure that the link count is zero
    # - Cygwin provides deferred unlinking, however,
    #   on Win9x the link count remains 1
    # On NFS the link count may still be 1 but we can't know that
    # we are on NFS.  Since we can't be sure, we'll defer it

    return 1 if $fh[3] == 0 || $^O eq 'cygwin';
  }
  # fall-through if we can't unlink now
  _deferred_unlink($fh, $path, 0);
  return 1;
}

#pod =item B<cmpstat>
#pod
#pod Compare C<stat> of filehandle with C<stat> of provided filename.  This
#pod can be used to check that the filename and filehandle initially point
#pod to the same file and that the number of links to the file is 1 (all
#pod fields returned by stat() are compared).
#pod
#pod   cmpstat($fh, $path)
#pod      or die "Error comparing handle with file";
#pod
#pod Returns false if the stat information differs or if the link count is
#pod greater than 1. Calls croak if there is a security anomaly.
#pod
#pod On certain platforms, for example Windows, not all the fields returned by stat()
#pod can be compared. For example, the C<dev> and C<rdev> fields seem to be
#pod different in Windows.  Also, it seems that the size of the file
#pod returned by stat() does not always agree, with C<stat(FH)> being more
#pod accurate than C<stat(filename)>, presumably because of caching issues
#pod even when using autoflush (this is usually overcome by waiting a while
#pod after writing to the tempfile before attempting to C<unlink0> it).
#pod
#pod Not exported by default.
#pod
#pod Current API available since 0.14.
#pod
#pod =cut

sub cmpstat {

  croak 'Usage: cmpstat(filehandle, filename)'
    unless scalar(@_) == 2;

  # Read args
  my ($fh, $path) = @_;

  warn "Comparing stat\n"
    if $DEBUG;

  # Stat the filehandle - which may be closed if someone has manually
  # closed the file. Can not turn off warnings without using $^W
  # unless we upgrade to 5.006 minimum requirement
  my @fh;
  {
    local ($^W) = 0;
    @fh = stat $fh;
  }
  return unless @fh;

  if ($fh[3] > 1 && $^W) {
    carp "unlink0: fstat found too many links; SB=@fh" if $^W;
  }

  # Stat the path
  my @path = stat $path;

  unless (@path) {
    carp "unlink0: $path is gone already" if $^W;
    return;
  }

  # this is no longer a file, but may be a directory, or worse
  unless (-f $path) {
    confess "panic: $path is no longer a file: SB=@fh";
  }

  # Do comparison of each member of the array
  # On WinNT dev and rdev seem to be different
  # depending on whether it is a file or a handle.
  # Cannot simply compare all members of the stat return
  # Select the ones we can use
  my @okstat = (0..$#fh);       # Use all by default
  if ($^O eq 'MSWin32') {
    @okstat = (1,2,3,4,5,7,8,9,10);
  } elsif ($^O eq 'os2') {
    @okstat = (0, 2..$#fh);
  } elsif ($^O eq 'VMS') {      # device and file ID are sufficient
    @okstat = (0, 1);
  } elsif ($^O eq 'dos') {
    @okstat = (0,2..7,11..$#fh);
  } elsif ($^O eq 'mpeix') {
    @okstat = (0..4,8..10);
  }

  # Now compare each entry explicitly by number
  for (@okstat) {
    print "Comparing: $_ : $fh[$_] and $path[$_]\n" if $DEBUG;
    # Use eq rather than == since rdev, blksize, and blocks (6, 11,
    # and 12) will be '' on platforms that do not support them.  This
    # is fine since we are only comparing integers.
    unless ($fh[$_] eq $path[$_]) {
      warn "Did not match $_ element of stat\n" if $DEBUG;
      return 0;
    }
  }

  return 1;
}

#pod =item B<unlink1>
#pod
#pod Similar to C<unlink0> except after file comparison using cmpstat, the
#pod filehandle is closed prior to attempting to unlink the file. This
#pod allows the file to be removed without using an END block, but does
#pod mean that the post-unlink comparison of the filehandle state provided
#pod by C<unlink0> is not available.
#pod
#pod   unlink1($fh, $path)
#pod      or die "Error closing and unlinking file";
#pod
#pod Usually called from the object destructor when using the OO interface.
#pod
#pod Not exported by default.
#pod
#pod This function is disabled if the global variable $KEEP_ALL is true.
#pod
#pod Can call croak() if there is a security anomaly during the stat()
#pod comparison.
#pod
#pod Current API available since 0.14.
#pod
#pod =cut

sub unlink1 {
  croak 'Usage: unlink1(filehandle, filename)'
    unless scalar(@_) == 2;

  # Read args
  my ($fh, $path) = @_;

  cmpstat($fh, $path) or return 0;

  # Close the file
  close( $fh ) or return 0;

  # Make sure the file is writable (for windows)
  _force_writable( $path );

  # return early (without unlink) if we have been instructed to retain files.
  return 1 if $KEEP_ALL;

  # remove the file
  return unlink($path);
}

#pod =item B<cleanup>
#pod
#pod Calling this function will cause any temp files or temp directories
#pod that are registered for removal to be removed. This happens automatically
#pod when the process exits but can be triggered manually if the caller is sure
#pod that none of the temp files are required. This method can be registered as
#pod an Apache callback.
#pod
#pod Note that if a temp directory is your current directory, it cannot be
#pod removed.  C<chdir()> out of the directory first before calling
#pod C<cleanup()>. (For the cleanup at program exit when the CLEANUP flag
#pod is set, this happens automatically.)
#pod
#pod On OSes where temp files are automatically removed when the temp file
#pod is closed, calling this function will have no effect other than to remove
#pod temporary directories (which may include temporary files).
#pod
#pod   File::Temp::cleanup();
#pod
#pod Not exported by default.
#pod
#pod Current API available since 0.15.
#pod
#pod =back
#pod
#pod =head1 PACKAGE VARIABLES
#pod
#pod These functions control the global state of the package.
#pod
#pod =over 4
#pod
#pod =item B<safe_level>
#pod
#pod Controls the lengths to which the module will go to check the safety of the
#pod temporary file or directory before proceeding.
#pod Options are:
#pod
#pod =over 8
#pod
#pod =item STANDARD
#pod
#pod Do the basic security measures to ensure the directory exists and is
#pod writable, that temporary files are opened only if they do not already
#pod exist, and that possible race conditions are avoided.  Finally the
#pod L<unlink0|"unlink0"> function is used to remove files safely.
#pod
#pod =item MEDIUM
#pod
#pod In addition to the STANDARD security, the output directory is checked
#pod to make sure that it is owned either by root or the user running the
#pod program. If the directory is writable by group or by other, it is then
#pod checked to make sure that the sticky bit is set.
#pod
#pod Will not work on platforms that do not support the C<-k> test
#pod for sticky bit.
#pod
#pod =item HIGH
#pod
#pod In addition to the MEDIUM security checks, also check for the
#pod possibility of ``chown() giveaway'' using the L<POSIX|POSIX>
#pod sysconf() function. If this is a possibility, each directory in the
#pod path is checked in turn for safeness, recursively walking back to the
#pod root directory.
#pod
#pod For platforms that do not support the L<POSIX|POSIX>
#pod C<_PC_CHOWN_RESTRICTED> symbol (for example, Windows NT) it is
#pod assumed that ``chown() giveaway'' is possible and the recursive test
#pod is performed.
#pod
#pod =back
#pod
#pod The level can be changed as follows:
#pod
#pod   File::Temp->safe_level( File::Temp::HIGH );
#pod
#pod The level constants are not exported by the module.
#pod
#pod Currently, you must be running at least perl v5.6.0 in order to
#pod run with MEDIUM or HIGH security. This is simply because the
#pod safety tests use functions from L<Fcntl|Fcntl> that are not
#pod available in older versions of perl. The problem is that the version
#pod number for Fcntl is the same in perl 5.6.0 and in 5.005_03 even though
#pod they are different versions.
#pod
#pod On systems that do not support the HIGH or MEDIUM safety levels
#pod (for example Win NT or OS/2) any attempt to change the level will
#pod be ignored. The decision to ignore rather than raise an exception
#pod allows portable programs to be written with high security in mind
#pod for the systems that can support this without those programs failing
#pod on systems where the extra tests are irrelevant.
#pod
#pod If you really need to see whether the change has been accepted
#pod simply examine the return value of C<safe_level>.
#pod
#pod   $newlevel = File::Temp->safe_level( File::Temp::HIGH );
#pod   die "Could not change to high security"
#pod       if $newlevel != File::Temp::HIGH;
#pod
#pod Available since 0.05.
#pod
#pod =cut

{
  # protect from using the variable itself
  my $LEVEL = STANDARD;
  sub safe_level {
    my $self = shift;
    if (@_) {
      my $level = shift;
      if (($level != STANDARD) && ($level != MEDIUM) && ($level != HIGH)) {
        carp "safe_level: Specified level ($level) not STANDARD, MEDIUM or HIGH - ignoring\n" if $^W;
      } else {
        # Don't allow this on perl 5.005 or earlier
        if ($] < 5.006 && $level != STANDARD) {
          # Cant do MEDIUM or HIGH checks
          croak "Currently requires perl 5.006 or newer to do the safe checks";
        }
        # Check that we are allowed to change level
        # Silently ignore if we can not.
        $LEVEL = $level if _can_do_level($level);
      }
    }
    return $LEVEL;
  }
}

#pod =item TopSystemUID
#pod
#pod This is the highest UID on the current system that refers to a root
#pod UID. This is used to make sure that the temporary directory is
#pod owned by a system UID (C<root>, C<bin>, C<sys> etc) rather than
#pod simply by root.
#pod
#pod This is required since on many unix systems C</tmp> is not owned
#pod by root.
#pod
#pod Default is to assume that any UID less than or equal to 10 is a root
#pod UID.
#pod
#pod   File::Temp->top_system_uid(10);
#pod   my $topid = File::Temp->top_system_uid;
#pod
#pod This value can be adjusted to reduce security checking if required.
#pod The value is only relevant when C<safe_level> is set to MEDIUM or higher.
#pod
#pod Available since 0.05.
#pod
#pod =cut

{
  my $TopSystemUID = 10;
  $TopSystemUID = 197108 if $^O eq 'interix'; # "Administrator"
  sub top_system_uid {
    my $self = shift;
    if (@_) {
      my $newuid = shift;
      croak "top_system_uid: UIDs should be numeric"
        unless $newuid =~ /^\d+$/s;
      $TopSystemUID = $newuid;
    }
    return $TopSystemUID;
  }
}

#pod =item B<$KEEP_ALL>
#pod
#pod Controls whether temporary files and directories should be retained
#pod regardless of any instructions in the program to remove them
#pod automatically.  This is useful for debugging but should not be used in
#pod production code.
#pod
#pod   $File::Temp::KEEP_ALL = 1;
#pod
#pod Default is for files to be removed as requested by the caller.
#pod
#pod In some cases, files will only be retained if this variable is true
#pod when the file is created. This means that you can not create a temporary
#pod file, set this variable and expect the temp file to still be around
#pod when the program exits.
#pod
#pod =item B<$DEBUG>
#pod
#pod Controls whether debugging messages should be enabled.
#pod
#pod   $File::Temp::DEBUG = 1;
#pod
#pod Default is for debugging mode to be disabled.
#pod
#pod Available since 0.15.
#pod
#pod =back
#pod
#pod =head1 WARNING
#pod
#pod For maximum security, endeavour always to avoid ever looking at,
#pod touching, or even imputing the existence of the filename.  You do not
#pod know that that filename is connected to the same file as the handle
#pod you have, and attempts to check this can only trigger more race
#pod conditions.  It's far more secure to use the filehandle alone and
#pod dispense with the filename altogether.
#pod
#pod If you need to pass the handle to something that expects a filename
#pod then on a unix system you can use C<"/dev/fd/" . fileno($fh)> for
#pod arbitrary programs. Perl code that uses the 2-argument version of
#pod C<< open >> can be passed C<< "+<=&" . fileno($fh) >>. Otherwise you
#pod will need to pass the filename. You will have to clear the
#pod close-on-exec bit on that file descriptor before passing it to another
#pod process.
#pod
#pod     use Fcntl qw/F_SETFD F_GETFD/;
#pod     fcntl($tmpfh, F_SETFD, 0)
#pod         or die "Can't clear close-on-exec flag on temp fh: $!\n";
#pod
#pod =head2 Temporary files and NFS
#pod
#pod Some problems are associated with using temporary files that reside
#pod on NFS file systems and it is recommended that a local filesystem
#pod is used whenever possible. Some of the security tests will most probably
#pod fail when the temp file is not local. Additionally, be aware that
#pod the performance of I/O operations over NFS will not be as good as for
#pod a local disk.
#pod
#pod =head2 Forking
#pod
#pod In some cases files created by File::Temp are removed from within an
#pod END block. Since END blocks are triggered when a child process exits
#pod (unless C<POSIX::_exit()> is used by the child) File::Temp takes care
#pod to only remove those temp files created by a particular process ID. This
#pod means that a child will not attempt to remove temp files created by the
#pod parent process.
#pod
#pod If you are forking many processes in parallel that are all creating
#pod temporary files, you may need to reset the random number seed using
#pod srand(EXPR) in each child else all the children will attempt to walk
#pod through the same set of random file names and may well cause
#pod themselves to give up if they exceed the number of retry attempts.
#pod
#pod =head2 Directory removal
#pod
#pod Note that if you have chdir'ed into the temporary directory and it is
#pod subsequently cleaned up (either in the END block or as part of object
#pod destruction), then you will get a warning from File::Path::rmtree().
#pod
#pod =head2 Taint mode
#pod
#pod If you need to run code under taint mode, updating to the latest
#pod L<File::Spec> is highly recommended.  On Windows, if the directory
#pod given by L<File::Spec::tmpdir> isn't writable, File::Temp will attempt
#pod to fallback to the user's local application data directory or croak
#pod with an error.
#pod
#pod =head2 BINMODE
#pod
#pod The file returned by File::Temp will have been opened in binary mode
#pod if such a mode is available. If that is not correct, use the C<binmode()>
#pod function to change the mode of the filehandle.
#pod
#pod Note that you can modify the encoding of a file opened by File::Temp
#pod also by using C<binmode()>.
#pod
#pod =head1 HISTORY
#pod
#pod Originally began life in May 1999 as an XS interface to the system
#pod mkstemp() function. In March 2000, the OpenBSD mkstemp() code was
#pod translated to Perl for total control of the code's
#pod security checking, to ensure the presence of the function regardless of
#pod operating system and to help with portability. The module was shipped
#pod as a standard part of perl from v5.6.1.
#pod
#pod Thanks to Tom Christiansen for suggesting that this module
#pod should be written and providing ideas for code improvements and
#pod security enhancements.
#pod
#pod =head1 SEE ALSO
#pod
#pod L<POSIX/tmpnam>, L<POSIX/tmpfile>, L<File::Spec>, L<File::Path>
#pod
#pod See L<IO::File> and L<File::MkTemp>, L<Apache::TempFile> for
#pod different implementations of temporary file handling.
#pod
#pod See L<File::Tempdir> for an alternative object-oriented wrapper for
#pod the C<tempdir> function.
#pod
#pod =cut

package ## hide from PAUSE
  File::Temp::Dir;

our $VERSION = '0.2309';

use File::Path qw/ rmtree /;
use strict;
use overload '""' => "STRINGIFY",
  '0+' => \&File::Temp::NUMIFY,
  fallback => 1;

# private class specifically to support tempdir objects
# created by File::Temp->newdir

# ostensibly the same method interface as File::Temp but without
# inheriting all the IO::Seekable methods and other cruft

# Read-only - returns the name of the temp directory

sub dirname {
  my $self = shift;
  return $self->{DIRNAME};
}

sub STRINGIFY {
  my $self = shift;
  return $self->dirname;
}

sub unlink_on_destroy {
  my $self = shift;
  if (@_) {
    $self->{CLEANUP} = shift;
  }
  return $self->{CLEANUP};
}

sub DESTROY {
  my $self = shift;
  local($., $@, $!, $^E, $?);
  if ($self->unlink_on_destroy &&
      $$ == $self->{LAUNCHPID} && !$File::Temp::KEEP_ALL) {
    if (-d $self->{REALNAME}) {
      # Some versions of rmtree will abort if you attempt to remove
      # the directory you are sitting in. We protect that and turn it
      # into a warning. We do this because this occurs during object
      # destruction and so can not be caught by the user.
      eval { rmtree($self->{REALNAME}, $File::Temp::DEBUG, 0); };
      warn $@ if ($@ && $^W);
    }
  }
}

1;


# vim: ts=2 sts=2 sw=2 et:

__END__

=pod

=encoding UTF-8

=head1 NAME

File::Temp - return name and handle of a temporary file safely

=head1 VERSION

version 0.2309

=head1 SYNOPSIS

  use File::Temp qw/ tempfile tempdir /;

  $fh = tempfile();
  ($fh, $filename) = tempfile();

  ($fh, $filename) = tempfile( $template, DIR => $dir);
  ($fh, $filename) = tempfile( $template, SUFFIX => '.dat');
  ($fh, $filename) = tempfile( $template, TMPDIR => 1 );

  binmode( $fh, ":utf8" );

  $dir = tempdir( CLEANUP => 1 );
  ($fh, $filename) = tempfile( DIR => $dir );

Object interface:

  require File::Temp;
  use File::Temp ();
  use File::Temp qw/ :seekable /;

  $fh = File::Temp->new();
  $fname = $fh->filename;

  $fh = File::Temp->new(TEMPLATE => $template);
  $fname = $fh->filename;

  $tmp = File::Temp->new( UNLINK => 0, SUFFIX => '.dat' );
  print $tmp "Some data\n";
  print "Filename is $tmp\n";
  $tmp->seek( 0, SEEK_END );

  $dir = File::Temp->newdir(); # CLEANUP => 1 by default

The following interfaces are provided for compatibility with
existing APIs. They should not be used in new code.

MkTemp family:

  use File::Temp qw/ :mktemp  /;

  ($fh, $file) = mkstemp( "tmpfileXXXXX" );
  ($fh, $file) = mkstemps( "tmpfileXXXXXX", $suffix);

  $tmpdir = mkdtemp( $template );

  $unopened_file = mktemp( $template );

POSIX functions:

  use File::Temp qw/ :POSIX /;

  $file = tmpnam();
  $fh = tmpfile();

  ($fh, $file) = tmpnam();

Compatibility functions:

  $unopened_file = File::Temp::tempnam( $dir, $pfx );

=head1 DESCRIPTION

C<File::Temp> can be used to create and open temporary files in a safe
way.  There is both a function interface and an object-oriented
interface.  The File::Temp constructor or the tempfile() function can
be used to return the name and the open filehandle of a temporary
file.  The tempdir() function can be used to create a temporary
directory.

The security aspect of temporary file creation is emphasized such that
a filehandle and filename are returned together.  This helps guarantee
that a race condition can not occur where the temporary file is
created by another process between checking for the existence of the
file and its opening.  Additional security levels are provided to
check, for example, that the sticky bit is set on world writable
directories.  See L<"safe_level"> for more information.

For compatibility with popular C library functions, Perl implementations of
the mkstemp() family of functions are provided. These are, mkstemp(),
mkstemps(), mkdtemp() and mktemp().

Additionally, implementations of the standard L<POSIX|POSIX>
tmpnam() and tmpfile() functions are provided if required.

Implementations of mktemp(), tmpnam(), and tempnam() are provided,
but should be used with caution since they return only a filename
that was valid when function was called, so cannot guarantee
that the file will not exist by the time the caller opens the filename.

Filehandles returned by these functions support the seekable methods.

=begin :__INTERNALS

=head1 PORTABILITY

This section is at the top in order to provide easier access to
porters.  It is not expected to be rendered by a standard pod
formatting tool. Please skip straight to the SYNOPSIS section if you
are not trying to port this module to a new platform.

This module is designed to be portable across operating systems and it
currently supports Unix, VMS, DOS, OS/2, Windows and Mac OS
(Classic). When porting to a new OS there are generally three main
issues that have to be solved:

=over 4

=item *

Can the OS unlink an open file? If it can not then the
C<_can_unlink_opened_file> method should be modified.

=item *

Are the return values from C<stat> reliable? By default all the
return values from C<stat> are compared when unlinking a temporary
file using the filename and the handle. Operating systems other than
unix do not always have valid entries in all fields. If utility function
C<File::Temp::unlink0> fails then the C<stat> comparison should be
modified accordingly.

=item *

Security. Systems that can not support a test for the sticky bit
on a directory can not use the MEDIUM and HIGH security tests.
The C<_can_do_level> method should be modified accordingly.

=back

=end :__INTERNALS

=head1 OBJECT-ORIENTED INTERFACE

This is the primary interface for interacting with
C<File::Temp>. Using the OO interface a temporary file can be created
when the object is constructed and the file can be removed when the
object is no longer required.

Note that there is no method to obtain the filehandle from the
C<File::Temp> object. The object itself acts as a filehandle.  The object
isa C<IO::Handle> and isa C<IO::Seekable> so all those methods are
available.

Also, the object is configured such that it stringifies to the name of the
temporary file and so can be compared to a filename directly.  It numifies
to the C<refaddr> the same as other handles and so can be compared to other
handles with C<==>.

    $fh eq $filename       # as a string
    $fh != \*STDOUT        # as a number

Available since 0.14.

=over 4

=item B<new>

Create a temporary file object.

  my $tmp = File::Temp->new();

by default the object is constructed as if C<tempfile>
was called without options, but with the additional behaviour
that the temporary file is removed by the object destructor
if UNLINK is set to true (the default).

Supported arguments are the same as for C<tempfile>: UNLINK
(defaulting to true), DIR, EXLOCK and SUFFIX. Additionally, the filename
template is specified using the TEMPLATE option. The OPEN option
is not supported (the file is always opened).

 $tmp = File::Temp->new( TEMPLATE => 'tempXXXXX',
                        DIR => 'mydir',
                        SUFFIX => '.dat');

Arguments are case insensitive.

Can call croak() if an error occurs.

Available since 0.14.

TEMPLATE available since 0.23

=item B<newdir>

Create a temporary directory using an object oriented interface.

  $dir = File::Temp->newdir();

By default the directory is deleted when the object goes out of scope.

Supports the same options as the C<tempdir> function. Note that directories
created with this method default to CLEANUP => 1.

  $dir = File::Temp->newdir( $template, %options );

A template may be specified either with a leading template or
with a TEMPLATE argument.

Available since 0.19.

TEMPLATE available since 0.23.

=item B<filename>

Return the name of the temporary file associated with this object
(if the object was created using the "new" constructor).

  $filename = $tmp->filename;

This method is called automatically when the object is used as
a string.

Current API available since 0.14

=item B<dirname>

Return the name of the temporary directory associated with this
object (if the object was created using the "newdir" constructor).

  $dirname = $tmpdir->dirname;

This method is called automatically when the object is used in string context.

=item B<unlink_on_destroy>

Control whether the file is unlinked when the object goes out of scope.
The file is removed if this value is true and $KEEP_ALL is not.

 $fh->unlink_on_destroy( 1 );

Default is for the file to be removed.

Current API available since 0.15

=item B<DESTROY>

When the object goes out of scope, the destructor is called. This
destructor will attempt to unlink the file (using L<unlink1|"unlink1">)
if the constructor was called with UNLINK set to 1 (the default state
if UNLINK is not specified).

No error is given if the unlink fails.

If the object has been passed to a child process during a fork, the
file will be deleted when the object goes out of scope in the parent.

For a temporary directory object the directory will be removed unless
the CLEANUP argument was used in the constructor (and set to false) or
C<unlink_on_destroy> was modified after creation.  Note that if a temp
directory is your current directory, it cannot be removed - a warning
will be given in this case.  C<chdir()> out of the directory before
letting the object go out of scope.

If the global variable $KEEP_ALL is true, the file or directory
will not be removed.

=back

=head1 FUNCTIONS

This section describes the recommended interface for generating
temporary files and directories.

=over 4

=item B<tempfile>

This is the basic function to generate temporary files.
The behaviour of the file can be changed using various options:

  $fh = tempfile();
  ($fh, $filename) = tempfile();

Create a temporary file in  the directory specified for temporary
files, as specified by the tmpdir() function in L<File::Spec>.

  ($fh, $filename) = tempfile($template);

Create a temporary file in the current directory using the supplied
template.  Trailing `X' characters are replaced with random letters to
generate the filename.  At least four `X' characters must be present
at the end of the template.

  ($fh, $filename) = tempfile($template, SUFFIX => $suffix)

Same as previously, except that a suffix is added to the template
after the `X' translation.  Useful for ensuring that a temporary
filename has a particular extension when needed by other applications.
But see the WARNING at the end.

  ($fh, $filename) = tempfile($template, DIR => $dir);

Translates the template as before except that a directory name
is specified.

  ($fh, $filename) = tempfile($template, TMPDIR => 1);

Equivalent to specifying a DIR of "File::Spec->tmpdir", writing the file
into the same temporary directory as would be used if no template was
specified at all.

  ($fh, $filename) = tempfile($template, UNLINK => 1);

Return the filename and filehandle as before except that the file is
automatically removed when the program exits (dependent on
$KEEP_ALL). Default is for the file to be removed if a file handle is
requested and to be kept if the filename is requested. In a scalar
context (where no filename is returned) the file is always deleted
either (depending on the operating system) on exit or when it is
closed (unless $KEEP_ALL is true when the temp file is created).

Use the object-oriented interface if fine-grained control of when
a file is removed is required.

If the template is not specified, a template is always
automatically generated. This temporary file is placed in tmpdir()
(L<File::Spec>) unless a directory is specified explicitly with the
DIR option.

  $fh = tempfile( DIR => $dir );

If called in scalar context, only the filehandle is returned and the
file will automatically be deleted when closed on operating systems
that support this (see the description of tmpfile() elsewhere in this
document).  This is the preferred mode of operation, as if you only
have a filehandle, you can never create a race condition by fumbling
with the filename. On systems that can not unlink an open file or can
not mark a file as temporary when it is opened (for example, Windows
NT uses the C<O_TEMPORARY> flag) the file is marked for deletion when
the program ends (equivalent to setting UNLINK to 1). The C<UNLINK>
flag is ignored if present.

  (undef, $filename) = tempfile($template, OPEN => 0);

This will return the filename based on the template but
will not open this file.  Cannot be used in conjunction with
UNLINK set to true. Default is to always open the file
to protect from possible race conditions. A warning is issued
if warnings are turned on. Consider using the tmpnam()
and mktemp() functions described elsewhere in this document
if opening the file is not required.

To open the temporary filehandle with O_EXLOCK (open with exclusive
file lock) use C<< EXLOCK=>1 >>. This is supported only by some
operating systems (most notably BSD derived systems). By default
EXLOCK will be false. Former C<File::Temp> versions set EXLOCK to
true, so to be sure to get an unlocked filehandle also with older
versions, explicitly set C<< EXLOCK=>0 >>.

  ($fh, $filename) = tempfile($template, EXLOCK => 1);

Options can be combined as required.

Will croak() if there is an error.

Available since 0.05.

UNLINK flag available since 0.10.

TMPDIR flag available since 0.19.

EXLOCK flag available since 0.19.

=item B<tempdir>

This is the recommended interface for creation of temporary
directories.  By default the directory will not be removed on exit
(that is, it won't be temporary; this behaviour can not be changed
because of issues with backwards compatibility). To enable removal
either use the CLEANUP option which will trigger removal on program
exit, or consider using the "newdir" method in the object interface which
will allow the directory to be cleaned up when the object goes out of
scope.

The behaviour of the function depends on the arguments:

  $tempdir = tempdir();

Create a directory in tmpdir() (see L<File::Spec|File::Spec>).

  $tempdir = tempdir( $template );

Create a directory from the supplied template. This template is
similar to that described for tempfile(). `X' characters at the end
of the template are replaced with random letters to construct the
directory name. At least four `X' characters must be in the template.

  $tempdir = tempdir ( DIR => $dir );

Specifies the directory to use for the temporary directory.
The temporary directory name is derived from an internal template.

  $tempdir = tempdir ( $template, DIR => $dir );

Prepend the supplied directory name to the template. The template
should not include parent directory specifications itself. Any parent
directory specifications are removed from the template before
prepending the supplied directory.

  $tempdir = tempdir ( $template, TMPDIR => 1 );

Using the supplied template, create the temporary directory in
a standard location for temporary files. Equivalent to doing

  $tempdir = tempdir ( $template, DIR => File::Spec->tmpdir);

but shorter. Parent directory specifications are stripped from the
template itself. The C<TMPDIR> option is ignored if C<DIR> is set
explicitly.  Additionally, C<TMPDIR> is implied if neither a template
nor a directory are supplied.

  $tempdir = tempdir( $template, CLEANUP => 1);

Create a temporary directory using the supplied template, but
attempt to remove it (and all files inside it) when the program
exits. Note that an attempt will be made to remove all files from
the directory even if they were not created by this module (otherwise
why ask to clean it up?). The directory removal is made with
the rmtree() function from the L<File::Path|File::Path> module.
Of course, if the template is not specified, the temporary directory
will be created in tmpdir() and will also be removed at program exit.

Will croak() if there is an error.

Current API available since 0.05.

=back

=head1 MKTEMP FUNCTIONS

The following functions are Perl implementations of the
mktemp() family of temp file generation system calls.

=over 4

=item B<mkstemp>

Given a template, returns a filehandle to the temporary file and the name
of the file.

  ($fh, $name) = mkstemp( $template );

In scalar context, just the filehandle is returned.

The template may be any filename with some number of X's appended
to it, for example F</tmp/temp.XXXX>. The trailing X's are replaced
with unique alphanumeric combinations.

Will croak() if there is an error.

Current API available since 0.05.

=item B<mkstemps>

Similar to mkstemp(), except that an extra argument can be supplied
with a suffix to be appended to the template.

  ($fh, $name) = mkstemps( $template, $suffix );

For example a template of C<testXXXXXX> and suffix of C<.dat>
would generate a file similar to F<testhGji_w.dat>.

Returns just the filehandle alone when called in scalar context.

Will croak() if there is an error.

Current API available since 0.05.

=item B<mkdtemp>

Create a directory from a template. The template must end in
X's that are replaced by the routine.

  $tmpdir_name = mkdtemp($template);

Returns the name of the temporary directory created.

Directory must be removed by the caller.

Will croak() if there is an error.

Current API available since 0.05.

=item B<mktemp>

Returns a valid temporary filename but does not guarantee
that the file will not be opened by someone else.

  $unopened_file = mktemp($template);

Template is the same as that required by mkstemp().

Will croak() if there is an error.

Current API available since 0.05.

=back

=head1 POSIX FUNCTIONS

This section describes the re-implementation of the tmpnam()
and tmpfile() functions described in L<POSIX>
using the mkstemp() from this module.

Unlike the L<POSIX|POSIX> implementations, the directory used
for the temporary file is not specified in a system include
file (C<P_tmpdir>) but simply depends on the choice of tmpdir()
returned by L<File::Spec|File::Spec>. On some implementations this
location can be set using the C<TMPDIR> environment variable, which
may not be secure.
If this is a problem, simply use mkstemp() and specify a template.

=over 4

=item B<tmpnam>

When called in scalar context, returns the full name (including path)
of a temporary file (uses mktemp()). The only check is that the file does
not already exist, but there is no guarantee that that condition will
continue to apply.

  $file = tmpnam();

When called in list context, a filehandle to the open file and
a filename are returned. This is achieved by calling mkstemp()
after constructing a suitable template.

  ($fh, $file) = tmpnam();

If possible, this form should be used to prevent possible
race conditions.

See L<File::Spec/tmpdir> for information on the choice of temporary
directory for a particular operating system.

Will croak() if there is an error.

Current API available since 0.05.

=item B<tmpfile>

Returns the filehandle of a temporary file.

  $fh = tmpfile();

The file is removed when the filehandle is closed or when the program
exits. No access to the filename is provided.

If the temporary file can not be created undef is returned.
Currently this command will probably not work when the temporary
directory is on an NFS file system.

Will croak() if there is an error.

Available since 0.05.

Returning undef if unable to create file added in 0.12.

=back

=head1 ADDITIONAL FUNCTIONS

These functions are provided for backwards compatibility
with common tempfile generation C library functions.

They are not exported and must be addressed using the full package
name.

=over 4

=item B<tempnam>

Return the name of a temporary file in the specified directory
using a prefix. The file is guaranteed not to exist at the time
the function was called, but such guarantees are good for one
clock tick only.  Always use the proper form of C<sysopen>
with C<O_CREAT | O_EXCL> if you must open such a filename.

  $filename = File::Temp::tempnam( $dir, $prefix );

Equivalent to running mktemp() with $dir/$prefixXXXXXXXX
(using unix file convention as an example)

Because this function uses mktemp(), it can suffer from race conditions.

Will croak() if there is an error.

Current API available since 0.05.

=back

=head1 UTILITY FUNCTIONS

Useful functions for dealing with the filehandle and filename.

=over 4

=item B<unlink0>

Given an open filehandle and the associated filename, make a safe
unlink. This is achieved by first checking that the filename and
filehandle initially point to the same file and that the number of
links to the file is 1 (all fields returned by stat() are compared).
Then the filename is unlinked and the filehandle checked once again to
verify that the number of links on that file is now 0.  This is the
closest you can come to making sure that the filename unlinked was the
same as the file whose descriptor you hold.

  unlink0($fh, $path)
     or die "Error unlinking file $path safely";

Returns false on error but croaks() if there is a security
anomaly. The filehandle is not closed since on some occasions this is
not required.

On some platforms, for example Windows NT, it is not possible to
unlink an open file (the file must be closed first). On those
platforms, the actual unlinking is deferred until the program ends and
good status is returned. A check is still performed to make sure that
the filehandle and filename are pointing to the same thing (but not at
the time the end block is executed since the deferred removal may not
have access to the filehandle).

Additionally, on Windows NT not all the fields returned by stat() can
be compared. For example, the C<dev> and C<rdev> fields seem to be
different.  Also, it seems that the size of the file returned by stat()
does not always agree, with C<stat(FH)> being more accurate than
C<stat(filename)>, presumably because of caching issues even when
using autoflush (this is usually overcome by waiting a while after
writing to the tempfile before attempting to C<unlink0> it).

Finally, on NFS file systems the link count of the file handle does
not always go to zero immediately after unlinking. Currently, this
command is expected to fail on NFS disks.

This function is disabled if the global variable $KEEP_ALL is true
and an unlink on open file is supported. If the unlink is to be deferred
to the END block, the file is still registered for removal.

This function should not be called if you are using the object oriented
interface since the it will interfere with the object destructor deleting
the file.

Available Since 0.05.

If can not unlink open file, defer removal until later available since 0.06.

=item B<cmpstat>

Compare C<stat> of filehandle with C<stat> of provided filename.  This
can be used to check that the filename and filehandle initially point
to the same file and that the number of links to the file is 1 (all
fields returned by stat() are compared).

  cmpstat($fh, $path)
     or die "Error comparing handle with file";

Returns false if the stat information differs or if the link count is
greater than 1. Calls croak if there is a security anomaly.

On certain platforms, for example Windows, not all the fields returned by stat()
can be compared. For example, the C<dev> and C<rdev> fields seem to be
different in Windows.  Also, it seems that the size of the file
returned by stat() does not always agree, with C<stat(FH)> being more
accurate than C<stat(filename)>, presumably because of caching issues
even when using autoflush (this is usually overcome by waiting a while
after writing to the tempfile before attempting to C<unlink0> it).

Not exported by default.

Current API available since 0.14.

=item B<unlink1>

Similar to C<unlink0> except after file comparison using cmpstat, the
filehandle is closed prior to attempting to unlink the file. This
allows the file to be removed without using an END block, but does
mean that the post-unlink comparison of the filehandle state provided
by C<unlink0> is not available.

  unlink1($fh, $path)
     or die "Error closing and unlinking file";

Usually called from the object destructor when using the OO interface.

Not exported by default.

This function is disabled if the global variable $KEEP_ALL is true.

Can call croak() if there is a security anomaly during the stat()
comparison.

Current API available since 0.14.

=item B<cleanup>

Calling this function will cause any temp files or temp directories
that are registered for removal to be removed. This happens automatically
when the process exits but can be triggered manually if the caller is sure
that none of the temp files are required. This method can be registered as
an Apache callback.

Note that if a temp directory is your current directory, it cannot be
removed.  C<chdir()> out of the directory first before calling
C<cleanup()>. (For the cleanup at program exit when the CLEANUP flag
is set, this happens automatically.)

On OSes where temp files are automatically removed when the temp file
is closed, calling this function will have no effect other than to remove
temporary directories (which may include temporary files).

  File::Temp::cleanup();

Not exported by default.

Current API available since 0.15.

=back

=head1 PACKAGE VARIABLES

These functions control the global state of the package.

=over 4

=item B<safe_level>

Controls the lengths to which the module will go to check the safety of the
temporary file or directory before proceeding.
Options are:

=over 8

=item STANDARD

Do the basic security measures to ensure the directory exists and is
writable, that temporary files are opened only if they do not already
exist, and that possible race conditions are avoided.  Finally the
L<unlink0|"unlink0"> function is used to remove files safely.

=item MEDIUM

In addition to the STANDARD security, the output directory is checked
to make sure that it is owned either by root or the user running the
program. If the directory is writable by group or by other, it is then
checked to make sure that the sticky bit is set.

Will not work on platforms that do not support the C<-k> test
for sticky bit.

=item HIGH

In addition to the MEDIUM security checks, also check for the
possibility of ``chown() giveaway'' using the L<POSIX|POSIX>
sysconf() function. If this is a possibility, each directory in the
path is checked in turn for safeness, recursively walking back to the
root directory.

For platforms that do not support the L<POSIX|POSIX>
C<_PC_CHOWN_RESTRICTED> symbol (for example, Windows NT) it is
assumed that ``chown() giveaway'' is possible and the recursive test
is performed.

=back

The level can be changed as follows:

  File::Temp->safe_level( File::Temp::HIGH );

The level constants are not exported by the module.

Currently, you must be running at least perl v5.6.0 in order to
run with MEDIUM or HIGH security. This is simply because the
safety tests use functions from L<Fcntl|Fcntl> that are not
available in older versions of perl. The problem is that the version
number for Fcntl is the same in perl 5.6.0 and in 5.005_03 even though
they are different versions.

On systems that do not support the HIGH or MEDIUM safety levels
(for example Win NT or OS/2) any attempt to change the level will
be ignored. The decision to ignore rather than raise an exception
allows portable programs to be written with high security in mind
for the systems that can support this without those programs failing
on systems where the extra tests are irrelevant.

If you really need to see whether the change has been accepted
simply examine the return value of C<safe_level>.

  $newlevel = File::Temp->safe_level( File::Temp::HIGH );
  die "Could not change to high security"
      if $newlevel != File::Temp::HIGH;

Available since 0.05.

=item TopSystemUID

This is the highest UID on the current system that refers to a root
UID. This is used to make sure that the temporary directory is
owned by a system UID (C<root>, C<bin>, C<sys> etc) rather than
simply by root.

This is required since on many unix systems C</tmp> is not owned
by root.

Default is to assume that any UID less than or equal to 10 is a root
UID.

  File::Temp->top_system_uid(10);
  my $topid = File::Temp->top_system_uid;

This value can be adjusted to reduce security checking if required.
The value is only relevant when C<safe_level> is set to MEDIUM or higher.

Available since 0.05.

=item B<$KEEP_ALL>

Controls whether temporary files and directories should be retained
regardless of any instructions in the program to remove them
automatically.  This is useful for debugging but should not be used in
production code.

  $File::Temp::KEEP_ALL = 1;

Default is for files to be removed as requested by the caller.

In some cases, files will only be retained if this variable is true
when the file is created. This means that you can not create a temporary
file, set this variable and expect the temp file to still be around
when the program exits.

=item B<$DEBUG>

Controls whether debugging messages should be enabled.

  $File::Temp::DEBUG = 1;

Default is for debugging mode to be disabled.

Available since 0.15.

=back

=head1 WARNING

For maximum security, endeavour always to avoid ever looking at,
touching, or even imputing the existence of the filename.  You do not
know that that filename is connected to the same file as the handle
you have, and attempts to check this can only trigger more race
conditions.  It's far more secure to use the filehandle alone and
dispense with the filename altogether.

If you need to pass the handle to something that expects a filename
then on a unix system you can use C<"/dev/fd/" . fileno($fh)> for
arbitrary programs. Perl code that uses the 2-argument version of
C<< open >> can be passed C<< "+<=&" . fileno($fh) >>. Otherwise you
will need to pass the filename. You will have to clear the
close-on-exec bit on that file descriptor before passing it to another
process.

    use Fcntl qw/F_SETFD F_GETFD/;
    fcntl($tmpfh, F_SETFD, 0)
        or die "Can't clear close-on-exec flag on temp fh: $!\n";

=head2 Temporary files and NFS

Some problems are associated with using temporary files that reside
on NFS file systems and it is recommended that a local filesystem
is used whenever possible. Some of the security tests will most probably
fail when the temp file is not local. Additionally, be aware that
the performance of I/O operations over NFS will not be as good as for
a local disk.

=head2 Forking

In some cases files created by File::Temp are removed from within an
END block. Since END blocks are triggered when a child process exits
(unless C<POSIX::_exit()> is used by the child) File::Temp takes care
to only remove those temp files created by a particular process ID. This
means that a child will not attempt to remove temp files created by the
parent process.

If you are forking many processes in parallel that are all creating
temporary files, you may need to reset the random number seed using
srand(EXPR) in each child else all the children will attempt to walk
through the same set of random file names and may well cause
themselves to give up if they exceed the number of retry attempts.

=head2 Directory removal

Note that if you have chdir'ed into the temporary directory and it is
subsequently cleaned up (either in the END block or as part of object
destruction), then you will get a warning from File::Path::rmtree().

=head2 Taint mode

If you need to run code under taint mode, updating to the latest
L<File::Spec> is highly recommended.  On Windows, if the directory
given by L<File::Spec::tmpdir> isn't writable, File::Temp will attempt
to fallback to the user's local application data directory or croak
with an error.

=head2 BINMODE

The file returned by File::Temp will have been opened in binary mode
if such a mode is available. If that is not correct, use the C<binmode()>
function to change the mode of the filehandle.

Note that you can modify the encoding of a file opened by File::Temp
also by using C<binmode()>.

=head1 HISTORY

Originally began life in May 1999 as an XS interface to the system
mkstemp() function. In March 2000, the OpenBSD mkstemp() code was
translated to Perl for total control of the code's
security checking, to ensure the presence of the function regardless of
operating system and to help with portability. The module was shipped
as a standard part of perl from v5.6.1.

Thanks to Tom Christiansen for suggesting that this module
should be written and providing ideas for code improvements and
security enhancements.

=head1 SEE ALSO

L<POSIX/tmpnam>, L<POSIX/tmpfile>, L<File::Spec>, L<File::Path>

See L<IO::File> and L<File::MkTemp>, L<Apache::TempFile> for
different implementations of temporary file handling.

See L<File::Tempdir> for an alternative object-oriented wrapper for
the C<tempdir> function.

=for Pod::Coverage STRINGIFY NUMIFY top_system_uid

=head1 SUPPORT

Bugs may be submitted through L<the RT bug tracker|https://rt.cpan.org/Public/Dist/Display.html?Name=File-Temp>
(or L<bug-File-Temp@rt.cpan.org|mailto:bug-File-Temp@rt.cpan.org>).

There is also a mailing list available for users of this distribution, at
L<http://lists.perl.org/list/cpan-workers.html>.

There is also an irc channel available for users of this distribution, at
L<C<#toolchain> on C<irc.perl.org>|irc://irc.perl.org/#toolchain>.

=head1 AUTHOR

Tim Jenness <tjenness@cpan.org>

=head1 CONTRIBUTORS

=for stopwords David Golden Karen Etheridge Slaven Rezic Peter Rabbitson Olivier Mengue Kevin Ryde John Acklam James E. Keenan Brian Mowrey Dagfinn Ilmari Mannsåker Steinbrunner Ed Avis Guillem Jover Ben Tilly

=over 4

=item *

David Golden <dagolden@cpan.org>

=item *

Karen Etheridge <ether@cpan.org>

=item *

Slaven Rezic <slaven@rezic.de>

=item *

Peter Rabbitson <ribasushi@cpan.org>

=item *

Olivier Mengue <dolmen@cpan.org>

=item *

David Golden <xdg@xdg.me>

=item *

Kevin Ryde <user42@zip.com.au>

=item *

Peter John Acklam <pjacklam@online.no>

=item *

Slaven Rezic <slaven.rezic@idealo.de>

=item *

James E. Keenan <jkeen@verizon.net>

=item *

Brian Mowrey <brian@drlabs.org>

=item *

Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>

=item *

David Steinbrunner <dsteinbrunner@pobox.com>

=item *

Ed Avis <eda@linux01.wcl.local>

=item *

Guillem Jover <guillem@hadrons.org>

=item *

Ben Tilly <btilly@gmail.com>

=back

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2019 by Tim Jenness and the UK Particle Physics and Astronomy Research Council.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut