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  # 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

inc/File/Temp.pm view on Meta::CPAN


# 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

inc/File/Temp.pm view on Meta::CPAN


#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

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