5 File::Temp - return name and handle of a temporary file safely
11 This section is at the top in order to provide easier access to
12 porters. It is not expected to be rendered by a standard pod
13 formatting tool. Please skip straight to the SYNOPSIS section if you
14 are not trying to port this module to a new platform.
16 This module is designed to be portable across operating systems and it
17 currently supports Unix, VMS, DOS, OS/2, Windows and Mac OS
18 (Classic). When porting to a new OS there are generally three main
19 issues that have to be solved:
25 Can the OS unlink an open file? If it can not then the
26 C<_can_unlink_opened_file> method should be modified.
30 Are the return values from C<stat> reliable? By default all the
31 return values from C<stat> are compared when unlinking a temporary
32 file using the filename and the handle. Operating systems other than
33 unix do not always have valid entries in all fields. If C<unlink0> fails
34 then the C<stat> comparison should be modified accordingly.
38 Security. Systems that can not support a test for the sticky bit
39 on a directory can not use the MEDIUM and HIGH security tests.
40 The C<_can_do_level> method should be modified accordingly.
48 use File::Temp qw/ tempfile tempdir /;
51 ($fh, $filename) = tempfile();
53 ($fh, $filename) = tempfile( $template, DIR => $dir);
54 ($fh, $filename) = tempfile( $template, SUFFIX => '.dat');
55 ($fh, $filename) = tempfile( $template, TMPDIR => 1 );
57 binmode( $fh, ":utf8" );
59 $dir = tempdir( CLEANUP => 1 );
60 ($fh, $filename) = tempfile( DIR => $dir );
66 use File::Temp qw/ :seekable /;
68 $fh = File::Temp->new();
69 $fname = $fh->filename;
71 $fh = File::Temp->new(TEMPLATE => $template);
72 $fname = $fh->filename;
74 $tmp = File::Temp->new( UNLINK => 0, SUFFIX => '.dat' );
75 print $tmp "Some data\n";
76 print "Filename is $tmp\n";
77 $tmp->seek( 0, SEEK_END );
79 The following interfaces are provided for compatibility with
80 existing APIs. They should not be used in new code.
84 use File::Temp qw/ :mktemp /;
86 ($fh, $file) = mkstemp( "tmpfileXXXXX" );
87 ($fh, $file) = mkstemps( "tmpfileXXXXXX", $suffix);
89 $tmpdir = mkdtemp( $template );
91 $unopened_file = mktemp( $template );
95 use File::Temp qw/ :POSIX /;
100 ($fh, $file) = tmpnam();
102 Compatibility functions:
104 $unopened_file = File::Temp::tempnam( $dir, $pfx );
108 C<File::Temp> can be used to create and open temporary files in a safe
109 way. There is both a function interface and an object-oriented
110 interface. The File::Temp constructor or the tempfile() function can
111 be used to return the name and the open filehandle of a temporary
112 file. The tempdir() function can be used to create a temporary
115 The security aspect of temporary file creation is emphasized such that
116 a filehandle and filename are returned together. This helps guarantee
117 that a race condition can not occur where the temporary file is
118 created by another process between checking for the existence of the
119 file and its opening. Additional security levels are provided to
120 check, for example, that the sticky bit is set on world writable
121 directories. See L<"safe_level"> for more information.
123 For compatibility with popular C library functions, Perl implementations of
124 the mkstemp() family of functions are provided. These are, mkstemp(),
125 mkstemps(), mkdtemp() and mktemp().
127 Additionally, implementations of the standard L<POSIX|POSIX>
128 tmpnam() and tmpfile() functions are provided if required.
130 Implementations of mktemp(), tmpnam(), and tempnam() are provided,
131 but should be used with caution since they return only a filename
132 that was valid when function was called, so cannot guarantee
133 that the file will not exist by the time the caller opens the filename.
135 Filehandles returned by these functions support the seekable methods.
139 # 5.6.0 gives us S_IWOTH, S_IWGRP, our and auto-vivifying filehandls
140 # People would like a version on 5.004 so give them what they want :-)
145 use File::Path qw/ rmtree /;
147 use IO::Seekable; # For SEEK_*
149 require VMS::Stdio if $^O eq 'VMS';
151 # pre-emptively load Carp::Heavy. If we don't when we run out of file
152 # handles and attempt to call croak() we get an error message telling
153 # us that Carp::Heavy won't load rather than an error telling us we
154 # have run out of file handles. We either preload croak() or we
155 # switch the calls to croak from _gettemp() to use die.
156 eval { require Carp::Heavy; };
158 # Need the Symbol package if we are running older perl
159 require Symbol if $] < 5.006;
161 ### For the OO interface
162 use base qw/ IO::Handle IO::Seekable /;
163 use overload '""' => "STRINGIFY", fallback => 1;
165 # use 'our' on v5.6.0
166 use vars qw($VERSION @EXPORT_OK %EXPORT_TAGS $DEBUG $KEEP_ALL);
171 # We are exporting functions
173 use base qw/Exporter/;
175 # Export list - to allow fine tuning of export table
193 # Groups of functions for export
196 'POSIX' => [qw/ tmpnam tmpfile /],
197 'mktemp' => [qw/ mktemp mkstemp mkstemps mkdtemp/],
198 'seekable' => [qw/ SEEK_SET SEEK_CUR SEEK_END /],
201 # add contents of these tags to @EXPORT
202 Exporter::export_tags('POSIX','mktemp','seekable');
206 $VERSION = '0.20_01';
208 # This is a list of characters that can be used in random filenames
210 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
211 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
212 0 1 2 3 4 5 6 7 8 9 _
215 # Maximum number of tries to make a temp file before failing
217 use constant MAX_TRIES => 1000;
219 # Minimum number of X characters that should be in a template
220 use constant MINX => 4;
222 # Default template when no template supplied
224 use constant TEMPXXX => 'X' x 10;
226 # Constants for the security level
228 use constant STANDARD => 0;
229 use constant MEDIUM => 1;
230 use constant HIGH => 2;
232 # OPENFLAGS. If we defined the flag to use with Sysopen here this gives
233 # us an optimisation when many temporary files are requested
235 my $OPENFLAGS = O_CREAT | O_EXCL | O_RDWR;
238 unless ($^O eq 'MacOS') {
239 for my $oflag (qw/ NOFOLLOW BINARY LARGEFILE NOINHERIT /) {
240 my ($bit, $func) = (0, "Fcntl::O_" . $oflag);
242 $OPENFLAGS |= $bit if eval {
243 # Make sure that redefined die handlers do not cause problems
245 local $SIG{__DIE__} = sub {};
246 local $SIG{__WARN__} = sub {};
251 # Special case O_EXLOCK
253 local $SIG{__DIE__} = sub {};
254 local $SIG{__WARN__} = sub {};
259 # On some systems the O_TEMPORARY flag can be used to tell the OS
260 # to automatically remove the file when it is closed. This is fine
261 # in most cases but not if tempfile is called with UNLINK=>0 and
262 # the filename is requested -- in the case where the filename is to
263 # be passed to another routine. This happens on windows. We overcome
264 # this by using a second open flags variable
266 my $OPENTEMPFLAGS = $OPENFLAGS;
267 unless ($^O eq 'MacOS') {
268 for my $oflag (qw/ TEMPORARY /) {
269 my ($bit, $func) = (0, "Fcntl::O_" . $oflag);
272 $OPENTEMPFLAGS |= $bit if eval {
273 # Make sure that redefined die handlers do not cause problems
275 local $SIG{__DIE__} = sub {};
276 local $SIG{__WARN__} = sub {};
283 # Private hash tracking which files have been created by each process id via the OO interface
284 my %FILES_CREATED_BY_OBJECT;
286 # INTERNAL ROUTINES - not to be used outside of package
288 # Generic routine for getting a temporary filename
289 # modelled on OpenBSD _gettemp() in mktemp.c
291 # The template must contain X's that are to be replaced
292 # with the random values
296 # TEMPLATE - string containing the XXXXX's that is converted
297 # to a random filename and opened if required
299 # Optionally, a hash can also be supplied containing specific options
300 # "open" => if true open the temp file, else just return the name
302 # "mkdir"=> if true, we are creating a temp directory rather than tempfile
304 # "suffixlen" => number of characters at end of PATH to be ignored.
306 # "unlink_on_close" => indicates that, if possible, the OS should remove
307 # the file as soon as it is closed. Usually indicates
308 # use of the O_TEMPORARY flag to sysopen.
309 # Usually irrelevant on unix
310 # "use_exlock" => Indicates that O_EXLOCK should be used. Default is true.
312 # Optionally a reference to a scalar can be passed into the function
313 # On error this will be used to store the reason for the error
314 # "ErrStr" => \$errstr
316 # "open" and "mkdir" can not both be true
317 # "unlink_on_close" is not used when "mkdir" is true.
319 # The default options are equivalent to mktemp().
322 # filehandle - open file handle (if called with doopen=1, else undef)
323 # temp name - name of the temp file or directory
326 # ($fh, $name) = _gettemp($template, "open" => 1);
328 # for the current version, failures are associated with
329 # stored in an error string and returned to give the reason whilst debugging
330 # This routine is not called by any external function
333 croak 'Usage: ($fh, $name) = _gettemp($template, OPTIONS);'
334 unless scalar(@_) >= 1;
336 # the internal error string - expect it to be overridden
337 # Need this in case the caller decides not to supply us a value
338 # need an anonymous scalar
346 "unlink_on_close" => 0,
348 "ErrStr" => \$tempErrStr,
352 my $template = shift;
353 if (ref($template)) {
354 # Use a warning here since we have not yet merged ErrStr
355 carp "File::Temp::_gettemp: template must not be a reference";
359 # Check that the number of entries on stack are even
360 if (scalar(@_) % 2 != 0) {
361 # Use a warning here since we have not yet merged ErrStr
362 carp "File::Temp::_gettemp: Must have even number of options";
366 # Read the options and merge with defaults
367 %options = (%options, @_) if @_;
369 # Make sure the error string is set to undef
370 ${$options{ErrStr}} = undef;
372 # Can not open the file and make a directory in a single call
373 if ($options{"open"} && $options{"mkdir"}) {
374 ${$options{ErrStr}} = "doopen and domkdir can not both be true\n";
378 # Find the start of the end of the Xs (position of last X)
379 # Substr starts from 0
380 my $start = length($template) - 1 - $options{"suffixlen"};
382 # Check that we have at least MINX x X (e.g. 'XXXX") at the end of the string
383 # (taking suffixlen into account). Any fewer is insecure.
385 # Do it using substr - no reason to use a pattern match since
386 # we know where we are looking and what we are looking for
388 if (substr($template, $start - MINX + 1, MINX) ne 'X' x MINX) {
389 ${$options{ErrStr}} = "The template must end with at least ".
390 MINX . " 'X' characters\n";
394 # Replace all the X at the end of the substring with a
395 # random character or just all the XX at the end of a full string.
396 # Do it as an if, since the suffix adjusts which section to replace
397 # and suffixlen=0 returns nothing if used in the substr directly
398 # and generate a full path from the template
400 my $path = _replace_XX($template, $options{"suffixlen"});
403 # Split the path into constituent parts - eventually we need to check
404 # whether the directory exists
405 # We need to know whether we are making a temp directory
408 my ($volume, $directories, $file);
409 my $parent; # parent directory
410 if ($options{"mkdir"}) {
411 # There is no filename at the end
412 ($volume, $directories, $file) = File::Spec->splitpath( $path, 1);
414 # The parent is then $directories without the last directory
415 # Split the directory and put it back together again
416 my @dirs = File::Spec->splitdir($directories);
418 # If @dirs only has one entry (i.e. the directory template) that means
419 # we are in the current directory
421 $parent = File::Spec->curdir;
424 if ($^O eq 'VMS') { # need volume to avoid relative dir spec
425 $parent = File::Spec->catdir($volume, @dirs[0..$#dirs-1]);
426 $parent = 'sys$disk:[]' if $parent eq '';
429 # Put it back together without the last one
430 $parent = File::Spec->catdir(@dirs[0..$#dirs-1]);
432 # ...and attach the volume (no filename)
433 $parent = File::Spec->catpath($volume, $parent, '');
440 # Get rid of the last filename (use File::Basename for this?)
441 ($volume, $directories, $file) = File::Spec->splitpath( $path );
443 # Join up without the file part
444 $parent = File::Spec->catpath($volume,$directories,'');
446 # If $parent is empty replace with curdir
447 $parent = File::Spec->curdir
448 unless $directories ne '';
452 # Check that the parent directories exist
453 # Do this even for the case where we are simply returning a name
454 # not a file -- no point returning a name that includes a directory
455 # that does not exist or is not writable
457 unless (-e $parent) {
458 ${$options{ErrStr}} = "Parent directory ($parent) does not exist";
461 unless (-d $parent) {
462 ${$options{ErrStr}} = "Parent directory ($parent) is not a directory";
466 if ( $^O eq 'cygwin' ) {
467 # No-op special case. Under Windows Cygwin (FAT32) the directory
468 # permissions cannot be trusted. Directories are always
471 elsif (not -w $parent) {
472 ${$options{ErrStr}} = "Parent directory ($parent) is not writable\n";
477 # Check the stickiness of the directory and chown giveaway if required
478 # If the directory is world writable the sticky bit
481 if (File::Temp->safe_level == MEDIUM) {
483 unless (_is_safe($parent,\$safeerr)) {
484 ${$options{ErrStr}} = "Parent directory ($parent) is not safe ($safeerr)";
487 } elsif (File::Temp->safe_level == HIGH) {
489 unless (_is_verysafe($parent, \$safeerr)) {
490 ${$options{ErrStr}} = "Parent directory ($parent) is not safe ($safeerr)";
496 # Now try MAX_TRIES time to open the file
497 for (my $i = 0; $i < MAX_TRIES; $i++) {
499 # Try to open the file if requested
500 if ($options{"open"}) {
503 # If we are running before perl5.6.0 we can not auto-vivify
505 $fh = &Symbol::gensym;
508 # Try to make sure this will be marked close-on-exec
509 # XXX: Win32 doesn't respect this, nor the proper fcntl,
510 # but may have O_NOINHERIT. This may or may not be in Fcntl.
513 # Attempt to open the file
514 my $open_success = undef;
515 if ( $^O eq 'VMS' and $options{"unlink_on_close"} && !$KEEP_ALL) {
516 # make it auto delete on close by setting FAB$V_DLT bit
517 $fh = VMS::Stdio::vmssysopen($path, $OPENFLAGS, 0600, 'fop=dlt');
520 my $flags = ( ($options{"unlink_on_close"} && !$KEEP_ALL) ?
523 $flags |= $LOCKFLAG if (defined $LOCKFLAG && $options{use_exlock});
524 $open_success = sysopen($fh, $path, $flags, 0600);
526 if ( $open_success ) {
528 # in case of odd umask force rw
531 # Opened successfully - return file handle and name
536 # Error opening file - abort with error
537 # if the reason was anything but EEXIST
538 unless ($!{EEXIST}) {
539 ${$options{ErrStr}} = "Could not create temp file $path: $!";
543 # Loop round for another try
546 } elsif ($options{"mkdir"}) {
548 # Open the temp directory
549 if (mkdir( $path, 0700)) {
550 # in case of odd umask
556 # Abort with error if the reason for failure was anything
558 unless ($!{EEXIST}) {
559 ${$options{ErrStr}} = "Could not create directory $path: $!";
563 # Loop round for another try
569 # Return true if the file can not be found
570 # Directory has been checked previously
572 return (undef, $path) unless -e $path;
574 # Try again until MAX_TRIES
578 # Did not successfully open the tempfile/dir
579 # so try again with a different set of random letters
580 # No point in trying to increment unless we have only
581 # 1 X say and the randomness could come up with the same
582 # file MAX_TRIES in a row.
584 # Store current attempt - in principal this implies that the
585 # 3rd time around the open attempt that the first temp file
586 # name could be generated again. Probably should store each
587 # attempt and make sure that none are repeated
589 my $original = $path;
590 my $counter = 0; # Stop infinite loop
595 # Generate new name from original template
596 $path = _replace_XX($template, $options{"suffixlen"});
600 } until ($path ne $original || $counter > $MAX_GUESS);
602 # Check for out of control looping
603 if ($counter > $MAX_GUESS) {
604 ${$options{ErrStr}} = "Tried to get a new temp name different to the previous value $MAX_GUESS times.\nSomething wrong with template?? ($template)";
610 # If we get here, we have run out of tries
611 ${ $options{ErrStr} } = "Have exceeded the maximum number of attempts ("
612 . MAX_TRIES . ") to open temp file/dir";
618 # Internal routine to replace the XXXX... with random characters
619 # This has to be done by _gettemp() every time it fails to
620 # open a temp file/dir
622 # Arguments: $template (the template with XXX),
623 # $ignore (number of characters at end to ignore)
625 # Returns: modified template
629 croak 'Usage: _replace_XX($template, $ignore)'
630 unless scalar(@_) == 2;
632 my ($path, $ignore) = @_;
634 # Do it as an if, since the suffix adjusts which section to replace
635 # and suffixlen=0 returns nothing if used in the substr directly
636 # Alternatively, could simply set $ignore to length($path)-1
637 # Don't want to always use substr when not required though.
638 my $end = ( $] >= 5.006 ? "\\z" : "\\Z" );
641 substr($path, 0, - $ignore) =~ s/X(?=X*$end)/$CHARS[ int( rand( @CHARS ) ) ]/ge;
643 $path =~ s/X(?=X*$end)/$CHARS[ int( rand( @CHARS ) ) ]/ge;
648 # Internal routine to force a temp file to be writable after
649 # it is created so that we can unlink it. Windows seems to occassionally
650 # force a file to be readonly when written to certain temp locations
651 sub _force_writable {
657 # internal routine to check to see if the directory is safe
658 # First checks to see if the directory is not owned by the
659 # current user or root. Then checks to see if anyone else
660 # can write to the directory and if so, checks to see if
661 # it has the sticky bit set
663 # Will not work on systems that do not support sticky bit
665 #Args: directory path to check
666 # Optionally: reference to scalar to contain error message
667 # Returns true if the path is safe and false otherwise.
668 # Returns undef if can not even run stat() on the path
670 # This routine based on version written by Tom Christiansen
672 # Presumably, by the time we actually attempt to create the
673 # file or directory in this directory, it may not be safe
674 # anymore... Have to run _is_safe directly after the open.
682 my @info = stat($path);
683 unless (scalar(@info)) {
684 $$err_ref = "stat(path) returned no values";
687 return 1 if $^O eq 'VMS'; # owner delete control at file level
689 # Check to see whether owner is neither superuser (or a system uid) nor me
690 # Use the effective uid from the $> variable
692 if ($info[4] > File::Temp->top_system_uid() && $info[4] != $>) {
694 Carp::cluck(sprintf "uid=$info[4] topuid=%s euid=$> path='$path'",
695 File::Temp->top_system_uid());
697 $$err_ref = "Directory owned neither by root nor the current user"
702 # check whether group or other can write file
703 # use 066 to detect either reading or writing
704 # use 022 to check writability
705 # Do it with S_IWOTH and S_IWGRP for portability (maybe)
707 if (($info[2] & &Fcntl::S_IWGRP) || # Is group writable?
708 ($info[2] & &Fcntl::S_IWOTH) ) { # Is world writable?
709 # Must be a directory
711 $$err_ref = "Path ($path) is not a directory"
715 # Must have sticky bit set
717 $$err_ref = "Sticky bit not set on $path when dir is group|world writable"
726 # Internal routine to check whether a directory is safe
727 # for temp files. Safer than _is_safe since it checks for
728 # the possibility of chown giveaway and if that is a possibility
729 # checks each directory in the path to see if it is safe (with _is_safe)
731 # If _PC_CHOWN_RESTRICTED is not set, does the full test of each
734 # Takes optional second arg as scalar ref to error reason
738 # Need POSIX - but only want to bother if really necessary due to overhead
742 print "_is_verysafe testing $path\n" if $DEBUG;
743 return 1 if $^O eq 'VMS'; # owner delete control at file level
747 # Should Get the value of _PC_CHOWN_RESTRICTED if it is defined
748 # and If it is not there do the extensive test
750 my $chown_restricted;
751 $chown_restricted = &POSIX::_PC_CHOWN_RESTRICTED()
752 if eval { &POSIX::_PC_CHOWN_RESTRICTED(); 1};
754 # If chown_resticted is set to some value we should test it
755 if (defined $chown_restricted) {
757 # Return if the current directory is safe
758 return _is_safe($path,$err_ref) if POSIX::sysconf( $chown_restricted );
762 # To reach this point either, the _PC_CHOWN_RESTRICTED symbol
763 # was not avialable or the symbol was there but chown giveaway
764 # is allowed. Either way, we now have to test the entire tree for
767 # Convert path to an absolute directory if required
768 unless (File::Spec->file_name_is_absolute($path)) {
769 $path = File::Spec->rel2abs($path);
772 # Split directory into components - assume no file
773 my ($volume, $directories, undef) = File::Spec->splitpath( $path, 1);
775 # Slightly less efficient than having a function in File::Spec
776 # to chop off the end of a directory or even a function that
777 # can handle ../ in a directory tree
778 # Sometimes splitdir() returns a blank at the end
779 # so we will probably check the bottom directory twice in some cases
780 my @dirs = File::Spec->splitdir($directories);
782 # Concatenate one less directory each time around
783 foreach my $pos (0.. $#dirs) {
784 # Get a directory name
785 my $dir = File::Spec->catpath($volume,
786 File::Spec->catdir(@dirs[0.. $#dirs - $pos]),
790 print "TESTING DIR $dir\n" if $DEBUG;
792 # Check the directory
793 return 0 unless _is_safe($dir,$err_ref);
802 # internal routine to determine whether unlink works on this
803 # platform for files that are currently open.
804 # Returns true if we can, false otherwise.
806 # Currently WinNT, OS/2 and VMS can not unlink an opened file
807 # On VMS this is because the O_EXCL flag is used to open the
808 # temporary file. Currently I do not know enough about the issues
809 # on VMS to decide whether O_EXCL is a requirement.
811 sub _can_unlink_opened_file {
813 if ($^O eq 'MSWin32' || $^O eq 'os2' || $^O eq 'VMS' || $^O eq 'dos' || $^O eq 'MacOS') {
821 # internal routine to decide which security levels are allowed
822 # see safe_level() for more information on this
824 # Controls whether the supplied security level is allowed
826 # $cando = _can_do_level( $level )
833 # Always have to be able to do STANDARD
834 return 1 if $level == STANDARD;
836 # Currently, the systems that can do HIGH or MEDIUM are identical
837 if ( $^O eq 'MSWin32' || $^O eq 'os2' || $^O eq 'cygwin' || $^O eq 'dos' || $^O eq 'MacOS' || $^O eq 'mpeix') {
845 # This routine sets up a deferred unlinking of a specified
846 # filename and filehandle. It is used in the following cases:
847 # - Called by unlink0 if an opened file can not be unlinked
848 # - Called by tempfile() if files are to be removed on shutdown
849 # - Called by tempdir() if directories are to be removed on shutdown
852 # _deferred_unlink( $fh, $fname, $isdir );
854 # - filehandle (so that it can be expclicitly closed if open
855 # - filename (the thing we want to remove)
856 # - isdir (flag to indicate that we are being given a directory)
857 # [and hence no filehandle]
859 # Status is not referred to since all the magic is done with an END block
862 # Will set up two lexical variables to contain all the files to be
863 # removed. One array for files, another for directories They will
864 # only exist in this block.
866 # This means we only have to set up a single END block to remove
869 # in order to prevent child processes inadvertently deleting the parent
870 # temp files we use a hash to store the temp files and directories
871 # created by a particular process id.
873 # %files_to_unlink contains values that are references to an array of
874 # array references containing the filehandle and filename associated with
876 my (%files_to_unlink, %dirs_to_unlink);
878 # Set up an end block to use these arrays
883 # Cleanup function. Always triggered on END but can be invoked
888 my @files = (exists $files_to_unlink{$$} ?
889 @{ $files_to_unlink{$$} } : () );
890 foreach my $file (@files) {
891 # close the filehandle without checking its state
892 # in order to make real sure that this is closed
893 # if its already closed then I dont care about the answer
894 # probably a better way to do this
895 close($file->[0]); # file handle is [0]
897 if (-f $file->[1]) { # file name is [1]
898 _force_writable( $file->[1] ); # for windows
899 unlink $file->[1] or warn "Error removing ".$file->[1];
903 my @dirs = (exists $dirs_to_unlink{$$} ?
904 @{ $dirs_to_unlink{$$} } : () );
905 foreach my $dir (@dirs) {
907 rmtree($dir, $DEBUG, 0);
912 @{ $files_to_unlink{$$} } = ()
913 if exists $files_to_unlink{$$};
914 @{ $dirs_to_unlink{$$} } = ()
915 if exists $dirs_to_unlink{$$};
920 # This is the sub called to register a file for deferred unlinking
921 # This could simply store the input parameters and defer everything
922 # until the END block. For now we do a bit of checking at this
923 # point in order to make sure that (1) we have a file/dir to delete
924 # and (2) we have been called with the correct arguments.
925 sub _deferred_unlink {
927 croak 'Usage: _deferred_unlink($fh, $fname, $isdir)'
928 unless scalar(@_) == 3;
930 my ($fh, $fname, $isdir) = @_;
932 warn "Setting up deferred removal of $fname\n"
935 # If we have a directory, check that it is a directory
940 # Directory exists so store it
941 # first on VMS turn []foo into [.foo] for rmtree
942 $fname = VMS::Filespec::vmspath($fname) if $^O eq 'VMS';
943 $dirs_to_unlink{$$} = []
944 unless exists $dirs_to_unlink{$$};
945 push (@{ $dirs_to_unlink{$$} }, $fname);
948 carp "Request to remove directory $fname could not be completed since it does not exist!\n" if $^W;
955 # file exists so store handle and name for later removal
956 $files_to_unlink{$$} = []
957 unless exists $files_to_unlink{$$};
958 push(@{ $files_to_unlink{$$} }, [$fh, $fname]);
961 carp "Request to remove file $fname could not be completed since it is not there!\n" if $^W;
971 =head1 OBJECT-ORIENTED INTERFACE
973 This is the primary interface for interacting with
974 C<File::Temp>. Using the OO interface a temporary file can be created
975 when the object is constructed and the file can be removed when the
976 object is no longer required.
978 Note that there is no method to obtain the filehandle from the
979 C<File::Temp> object. The object itself acts as a filehandle. Also,
980 the object is configured such that it stringifies to the name of the
981 temporary file, and can be compared to a filename directly. The object
982 isa C<IO::Handle> and isa C<IO::Seekable> so all those methods are
989 Create a temporary file object.
991 my $tmp = File::Temp->new();
993 by default the object is constructed as if C<tempfile>
994 was called without options, but with the additional behaviour
995 that the temporary file is removed by the object destructor
996 if UNLINK is set to true (the default).
998 Supported arguments are the same as for C<tempfile>: UNLINK
999 (defaulting to true), DIR, EXLOCK and SUFFIX. Additionally, the filename
1000 template is specified using the TEMPLATE option. The OPEN option
1001 is not supported (the file is always opened).
1003 $tmp = File::Temp->new( TEMPLATE => 'tempXXXXX',
1007 Arguments are case insensitive.
1009 Can call croak() if an error occurs.
1015 my $class = ref($proto) || $proto;
1017 # read arguments and convert keys to upper case
1019 %args = map { uc($_), $args{$_} } keys %args;
1021 # see if they are unlinking (defaulting to yes)
1022 my $unlink = (exists $args{UNLINK} ? $args{UNLINK} : 1 );
1023 delete $args{UNLINK};
1025 # template (store it in an error so that it will
1026 # disappear from the arg list of tempfile
1027 my @template = ( exists $args{TEMPLATE} ? $args{TEMPLATE} : () );
1028 delete $args{TEMPLATE};
1033 # Open the file and retain file handle and file name
1034 my ($fh, $path) = tempfile( @template, %args );
1036 print "Tmp: $fh - $path\n" if $DEBUG;
1038 # Store the filename in the scalar slot
1041 # Cache the filename by pid so that the destructor can decide whether to remove it
1042 $FILES_CREATED_BY_OBJECT{$$}{$path} = 1;
1044 # Store unlink information in hash slot (plus other constructor info)
1050 # final method-based configuration
1051 $fh->unlink_on_destroy( $unlink );
1058 Create a temporary directory using an object oriented interface.
1060 $dir = File::Temp->newdir();
1062 By default the directory is deleted when the object goes out of scope.
1064 Supports the same options as the C<tempdir> function. Note that directories
1065 created with this method default to CLEANUP => 1.
1067 $dir = File::Temp->newdir( $template, %options );
1074 # need to handle args as in tempdir because we have to force CLEANUP
1075 # default without passing CLEANUP to tempdir
1076 my $template = (scalar(@_) % 2 == 1 ? shift(@_) : undef );
1078 my $cleanup = (exists $options{CLEANUP} ? $options{CLEANUP} : 1 );
1080 delete $options{CLEANUP};
1083 if (defined $template) {
1084 $tempdir = tempdir( $template, %options );
1086 $tempdir = tempdir( %options );
1088 return bless { DIRNAME => $tempdir,
1089 CLEANUP => $cleanup,
1091 }, "File::Temp::Dir";
1096 Return the name of the temporary file associated with this object
1097 (if the object was created using the "new" constructor).
1099 $filename = $tmp->filename;
1101 This method is called automatically when the object is used as
1113 return $self->filename;
1118 Return the name of the temporary directory associated with this
1119 object (if the object was created using the "newdir" constructor).
1121 $dirname = $tmpdir->dirname;
1123 This method is called automatically when the object is used in string context.
1125 =item B<unlink_on_destroy>
1127 Control whether the file is unlinked when the object goes out of scope.
1128 The file is removed if this value is true and $KEEP_ALL is not.
1130 $fh->unlink_on_destroy( 1 );
1132 Default is for the file to be removed.
1136 sub unlink_on_destroy {
1139 ${*$self}{UNLINK} = shift;
1141 return ${*$self}{UNLINK};
1146 When the object goes out of scope, the destructor is called. This
1147 destructor will attempt to unlink the file (using C<unlink1>)
1148 if the constructor was called with UNLINK set to 1 (the default state
1149 if UNLINK is not specified).
1151 No error is given if the unlink fails.
1153 If the object has been passed to a child process during a fork, the
1154 file will be deleted when the object goes out of scope in the parent.
1156 For a temporary directory object the directory will be removed
1157 unless the CLEANUP argument was used in the constructor (and set to
1158 false) or C<unlink_on_destroy> was modified after creation.
1160 If the global variable $KEEP_ALL is true, the file or directory
1161 will not be removed.
1167 if (${*$self}{UNLINK} && !$KEEP_ALL) {
1168 print "# ---------> Unlinking $self\n" if $DEBUG;
1170 # only delete if this process created it
1171 return unless exists $FILES_CREATED_BY_OBJECT{$$}{$self->filename};
1173 # The unlink1 may fail if the file has been closed
1174 # by the caller. This leaves us with the decision
1175 # of whether to refuse to remove the file or simply
1176 # do an unlink without test. Seems to be silly
1177 # to do this when we are trying to be careful
1179 _force_writable( $self->filename ); # for windows
1180 unlink1( $self, $self->filename )
1181 or unlink($self->filename);
1189 This section describes the recommended interface for generating
1190 temporary files and directories.
1196 This is the basic function to generate temporary files.
1197 The behaviour of the file can be changed using various options:
1200 ($fh, $filename) = tempfile();
1202 Create a temporary file in the directory specified for temporary
1203 files, as specified by the tmpdir() function in L<File::Spec>.
1205 ($fh, $filename) = tempfile($template);
1207 Create a temporary file in the current directory using the supplied
1208 template. Trailing `X' characters are replaced with random letters to
1209 generate the filename. At least four `X' characters must be present
1210 at the end of the template.
1212 ($fh, $filename) = tempfile($template, SUFFIX => $suffix)
1214 Same as previously, except that a suffix is added to the template
1215 after the `X' translation. Useful for ensuring that a temporary
1216 filename has a particular extension when needed by other applications.
1217 But see the WARNING at the end.
1219 ($fh, $filename) = tempfile($template, DIR => $dir);
1221 Translates the template as before except that a directory name
1224 ($fh, $filename) = tempfile($template, TMPDIR => 1);
1226 Equivalent to specifying a DIR of "File::Spec->tmpdir", writing the file
1227 into the same temporary directory as would be used if no template was
1230 ($fh, $filename) = tempfile($template, UNLINK => 1);
1232 Return the filename and filehandle as before except that the file is
1233 automatically removed when the program exits (dependent on
1234 $KEEP_ALL). Default is for the file to be removed if a file handle is
1235 requested and to be kept if the filename is requested. In a scalar
1236 context (where no filename is returned) the file is always deleted
1237 either (depending on the operating system) on exit or when it is
1238 closed (unless $KEEP_ALL is true when the temp file is created).
1240 Use the object-oriented interface if fine-grained control of when
1241 a file is removed is required.
1243 If the template is not specified, a template is always
1244 automatically generated. This temporary file is placed in tmpdir()
1245 (L<File::Spec>) unless a directory is specified explicitly with the
1248 $fh = tempfile( DIR => $dir );
1250 If called in scalar context, only the filehandle is returned and the
1251 file will automatically be deleted when closed on operating systems
1252 that support this (see the description of tmpfile() elsewhere in this
1253 document). This is the preferred mode of operation, as if you only
1254 have a filehandle, you can never create a race condition by fumbling
1255 with the filename. On systems that can not unlink an open file or can
1256 not mark a file as temporary when it is opened (for example, Windows
1257 NT uses the C<O_TEMPORARY> flag) the file is marked for deletion when
1258 the program ends (equivalent to setting UNLINK to 1). The C<UNLINK>
1259 flag is ignored if present.
1261 (undef, $filename) = tempfile($template, OPEN => 0);
1263 This will return the filename based on the template but
1264 will not open this file. Cannot be used in conjunction with
1265 UNLINK set to true. Default is to always open the file
1266 to protect from possible race conditions. A warning is issued
1267 if warnings are turned on. Consider using the tmpnam()
1268 and mktemp() functions described elsewhere in this document
1269 if opening the file is not required.
1271 If the operating system supports it (for example BSD derived systems), the
1272 filehandle will be opened with O_EXLOCK (open with exclusive file lock).
1273 This can sometimes cause problems if the intention is to pass the filename
1274 to another system that expects to take an exclusive lock itself (such as
1275 DBD::SQLite) whilst ensuring that the tempfile is not reused. In this
1276 situation the "EXLOCK" option can be passed to tempfile. By default EXLOCK
1277 will be true (this retains compatibility with earlier releases).
1279 ($fh, $filename) = tempfile($template, EXLOCK => 0);
1281 Options can be combined as required.
1283 Will croak() if there is an error.
1289 # Can not check for argument count since we can have any
1294 "DIR" => undef, # Directory prefix
1295 "SUFFIX" => '', # Template suffix
1296 "UNLINK" => 0, # Do not unlink file on exit
1297 "OPEN" => 1, # Open file
1298 "TMPDIR" => 0, # Place tempfile in tempdir if template specified
1299 "EXLOCK" => 1, # Open file with O_EXLOCK
1302 # Check to see whether we have an odd or even number of arguments
1303 my $template = (scalar(@_) % 2 == 1 ? shift(@_) : undef);
1305 # Read the options and merge with defaults
1306 %options = (%options, @_) if @_;
1308 # First decision is whether or not to open the file
1309 if (! $options{"OPEN"}) {
1311 warn "tempfile(): temporary filename requested but not opened.\nPossibly unsafe, consider using tempfile() with OPEN set to true\n"
1316 if ($options{"DIR"} and $^O eq 'VMS') {
1318 # on VMS turn []foo into [.foo] for concatenation
1319 $options{"DIR"} = VMS::Filespec::vmspath($options{"DIR"});
1322 # Construct the template
1324 # Have a choice of trying to work around the mkstemp/mktemp/tmpnam etc
1325 # functions or simply constructing a template and using _gettemp()
1326 # explicitly. Go for the latter
1328 # First generate a template if not defined and prefix the directory
1329 # If no template must prefix the temp directory
1330 if (defined $template) {
1331 # End up with current directory if neither DIR not TMPDIR are set
1332 if ($options{"DIR"}) {
1334 $template = File::Spec->catfile($options{"DIR"}, $template);
1336 } elsif ($options{TMPDIR}) {
1338 $template = File::Spec->catfile(File::Spec->tmpdir, $template );
1344 if ($options{"DIR"}) {
1346 $template = File::Spec->catfile($options{"DIR"}, TEMPXXX);
1350 $template = File::Spec->catfile(File::Spec->tmpdir, TEMPXXX);
1357 $template .= $options{"SUFFIX"};
1359 # Determine whether we should tell _gettemp to unlink the file
1360 # On unix this is irrelevant and can be worked out after the file is
1361 # opened (simply by unlinking the open filehandle). On Windows or VMS
1362 # we have to indicate temporary-ness when we open the file. In general
1363 # we only want a true temporary file if we are returning just the
1364 # filehandle - if the user wants the filename they probably do not
1365 # want the file to disappear as soon as they close it (which may be
1366 # important if they want a child process to use the file)
1367 # For this reason, tie unlink_on_close to the return context regardless
1369 my $unlink_on_close = ( wantarray ? 0 : 1);
1372 my ($fh, $path, $errstr);
1373 croak "Error in tempfile() using $template: $errstr"
1374 unless (($fh, $path) = _gettemp($template,
1375 "open" => $options{'OPEN'},
1377 "unlink_on_close" => $unlink_on_close,
1378 "suffixlen" => length($options{'SUFFIX'}),
1379 "ErrStr" => \$errstr,
1380 "use_exlock" => $options{EXLOCK},
1383 # Set up an exit handler that can do whatever is right for the
1384 # system. This removes files at exit when requested explicitly or when
1385 # system is asked to unlink_on_close but is unable to do so because
1386 # of OS limitations.
1387 # The latter should be achieved by using a tied filehandle.
1388 # Do not check return status since this is all done with END blocks.
1389 _deferred_unlink($fh, $path, 0) if $options{"UNLINK"};
1394 if ($options{'OPEN'}) {
1395 return ($fh, $path);
1397 return (undef, $path);
1402 # Unlink the file. It is up to unlink0 to decide what to do with
1403 # this (whether to unlink now or to defer until later)
1404 unlink0($fh, $path) or croak "Error unlinking file $path using unlink0";
1406 # Return just the filehandle.
1415 This is the recommended interface for creation of temporary
1416 directories. By default the directory will not be removed on exit
1417 (that is, it won't be temporary; this behaviour can not be changed
1418 because of issues with backwards compatibility). To enable removal
1419 either use the CLEANUP option which will trigger removal on program
1420 exit, or consider using the "newdir" method in the object interface which
1421 will allow the directory to be cleaned up when the object goes out of
1424 The behaviour of the function depends on the arguments:
1426 $tempdir = tempdir();
1428 Create a directory in tmpdir() (see L<File::Spec|File::Spec>).
1430 $tempdir = tempdir( $template );
1432 Create a directory from the supplied template. This template is
1433 similar to that described for tempfile(). `X' characters at the end
1434 of the template are replaced with random letters to construct the
1435 directory name. At least four `X' characters must be in the template.
1437 $tempdir = tempdir ( DIR => $dir );
1439 Specifies the directory to use for the temporary directory.
1440 The temporary directory name is derived from an internal template.
1442 $tempdir = tempdir ( $template, DIR => $dir );
1444 Prepend the supplied directory name to the template. The template
1445 should not include parent directory specifications itself. Any parent
1446 directory specifications are removed from the template before
1447 prepending the supplied directory.
1449 $tempdir = tempdir ( $template, TMPDIR => 1 );
1451 Using the supplied template, create the temporary directory in
1452 a standard location for temporary files. Equivalent to doing
1454 $tempdir = tempdir ( $template, DIR => File::Spec->tmpdir);
1456 but shorter. Parent directory specifications are stripped from the
1457 template itself. The C<TMPDIR> option is ignored if C<DIR> is set
1458 explicitly. Additionally, C<TMPDIR> is implied if neither a template
1459 nor a directory are supplied.
1461 $tempdir = tempdir( $template, CLEANUP => 1);
1463 Create a temporary directory using the supplied template, but
1464 attempt to remove it (and all files inside it) when the program
1465 exits. Note that an attempt will be made to remove all files from
1466 the directory even if they were not created by this module (otherwise
1467 why ask to clean it up?). The directory removal is made with
1468 the rmtree() function from the L<File::Path|File::Path> module.
1469 Of course, if the template is not specified, the temporary directory
1470 will be created in tmpdir() and will also be removed at program exit.
1472 Will croak() if there is an error.
1480 # Can not check for argument count since we can have any
1485 "CLEANUP" => 0, # Remove directory on exit
1486 "DIR" => '', # Root directory
1487 "TMPDIR" => 0, # Use tempdir with template
1490 # Check to see whether we have an odd or even number of arguments
1491 my $template = (scalar(@_) % 2 == 1 ? shift(@_) : undef );
1493 # Read the options and merge with defaults
1494 %options = (%options, @_) if @_;
1496 # Modify or generate the template
1498 # Deal with the DIR and TMPDIR options
1499 if (defined $template) {
1501 # Need to strip directory path if using DIR or TMPDIR
1502 if ($options{'TMPDIR'} || $options{'DIR'}) {
1504 # Strip parent directory from the filename
1506 # There is no filename at the end
1507 $template = VMS::Filespec::vmspath($template) if $^O eq 'VMS';
1508 my ($volume, $directories, undef) = File::Spec->splitpath( $template, 1);
1510 # Last directory is then our template
1511 $template = (File::Spec->splitdir($directories))[-1];
1513 # Prepend the supplied directory or temp dir
1514 if ($options{"DIR"}) {
1516 $template = File::Spec->catdir($options{"DIR"}, $template);
1518 } elsif ($options{TMPDIR}) {
1521 $template = File::Spec->catdir(File::Spec->tmpdir, $template);
1529 if ($options{"DIR"}) {
1531 $template = File::Spec->catdir($options{"DIR"}, TEMPXXX);
1535 $template = File::Spec->catdir(File::Spec->tmpdir, TEMPXXX);
1541 # Create the directory
1544 if ($^O eq 'VMS') { # dir names can end in delimiters
1545 $template =~ m/([\.\]:>]+)$/;
1546 $suffixlen = length($1);
1548 if ( ($^O eq 'MacOS') && (substr($template, -1) eq ':') ) {
1549 # dir name has a trailing ':'
1554 croak "Error in tempdir() using $template: $errstr"
1555 unless ((undef, $tempdir) = _gettemp($template,
1558 "suffixlen" => $suffixlen,
1559 "ErrStr" => \$errstr,
1562 # Install exit handler; must be dynamic to get lexical
1563 if ( $options{'CLEANUP'} && -d $tempdir) {
1564 _deferred_unlink(undef, $tempdir, 1);
1567 # Return the dir name
1574 =head1 MKTEMP FUNCTIONS
1576 The following functions are Perl implementations of the
1577 mktemp() family of temp file generation system calls.
1583 Given a template, returns a filehandle to the temporary file and the name
1586 ($fh, $name) = mkstemp( $template );
1588 In scalar context, just the filehandle is returned.
1590 The template may be any filename with some number of X's appended
1591 to it, for example F</tmp/temp.XXXX>. The trailing X's are replaced
1592 with unique alphanumeric combinations.
1594 Will croak() if there is an error.
1602 croak "Usage: mkstemp(template)"
1605 my $template = shift;
1607 my ($fh, $path, $errstr);
1608 croak "Error in mkstemp using $template: $errstr"
1609 unless (($fh, $path) = _gettemp($template,
1613 "ErrStr" => \$errstr,
1617 return ($fh, $path);
1627 Similar to mkstemp(), except that an extra argument can be supplied
1628 with a suffix to be appended to the template.
1630 ($fh, $name) = mkstemps( $template, $suffix );
1632 For example a template of C<testXXXXXX> and suffix of C<.dat>
1633 would generate a file similar to F<testhGji_w.dat>.
1635 Returns just the filehandle alone when called in scalar context.
1637 Will croak() if there is an error.
1643 croak "Usage: mkstemps(template, suffix)"
1647 my $template = shift;
1650 $template .= $suffix;
1652 my ($fh, $path, $errstr);
1653 croak "Error in mkstemps using $template: $errstr"
1654 unless (($fh, $path) = _gettemp($template,
1657 "suffixlen" => length($suffix),
1658 "ErrStr" => \$errstr,
1662 return ($fh, $path);
1671 Create a directory from a template. The template must end in
1672 X's that are replaced by the routine.
1674 $tmpdir_name = mkdtemp($template);
1676 Returns the name of the temporary directory created.
1678 Directory must be removed by the caller.
1680 Will croak() if there is an error.
1688 croak "Usage: mkdtemp(template)"
1691 my $template = shift;
1693 if ($^O eq 'VMS') { # dir names can end in delimiters
1694 $template =~ m/([\.\]:>]+)$/;
1695 $suffixlen = length($1);
1697 if ( ($^O eq 'MacOS') && (substr($template, -1) eq ':') ) {
1698 # dir name has a trailing ':'
1701 my ($junk, $tmpdir, $errstr);
1702 croak "Error creating temp directory from template $template\: $errstr"
1703 unless (($junk, $tmpdir) = _gettemp($template,
1706 "suffixlen" => $suffixlen,
1707 "ErrStr" => \$errstr,
1716 Returns a valid temporary filename but does not guarantee
1717 that the file will not be opened by someone else.
1719 $unopened_file = mktemp($template);
1721 Template is the same as that required by mkstemp().
1723 Will croak() if there is an error.
1729 croak "Usage: mktemp(template)"
1732 my $template = shift;
1734 my ($tmpname, $junk, $errstr);
1735 croak "Error getting name to temp file from template $template: $errstr"
1736 unless (($junk, $tmpname) = _gettemp($template,
1740 "ErrStr" => \$errstr,
1748 =head1 POSIX FUNCTIONS
1750 This section describes the re-implementation of the tmpnam()
1751 and tmpfile() functions described in L<POSIX>
1752 using the mkstemp() from this module.
1754 Unlike the L<POSIX|POSIX> implementations, the directory used
1755 for the temporary file is not specified in a system include
1756 file (C<P_tmpdir>) but simply depends on the choice of tmpdir()
1757 returned by L<File::Spec|File::Spec>. On some implementations this
1758 location can be set using the C<TMPDIR> environment variable, which
1760 If this is a problem, simply use mkstemp() and specify a template.
1766 When called in scalar context, returns the full name (including path)
1767 of a temporary file (uses mktemp()). The only check is that the file does
1768 not already exist, but there is no guarantee that that condition will
1773 When called in list context, a filehandle to the open file and
1774 a filename are returned. This is achieved by calling mkstemp()
1775 after constructing a suitable template.
1777 ($fh, $file) = tmpnam();
1779 If possible, this form should be used to prevent possible
1782 See L<File::Spec/tmpdir> for information on the choice of temporary
1783 directory for a particular operating system.
1785 Will croak() if there is an error.
1791 # Retrieve the temporary directory name
1792 my $tmpdir = File::Spec->tmpdir;
1794 croak "Error temporary directory is not writable"
1797 # Use a ten character template and append to tmpdir
1798 my $template = File::Spec->catfile($tmpdir, TEMPXXX);
1801 return mkstemp($template);
1803 return mktemp($template);
1810 Returns the filehandle of a temporary file.
1814 The file is removed when the filehandle is closed or when the program
1815 exits. No access to the filename is provided.
1817 If the temporary file can not be created undef is returned.
1818 Currently this command will probably not work when the temporary
1819 directory is on an NFS file system.
1821 Will croak() if there is an error.
1827 # Simply call tmpnam() in a list context
1828 my ($fh, $file) = tmpnam();
1830 # Make sure file is removed when filehandle is closed
1831 # This will fail on NFS
1841 =head1 ADDITIONAL FUNCTIONS
1843 These functions are provided for backwards compatibility
1844 with common tempfile generation C library functions.
1846 They are not exported and must be addressed using the full package
1853 Return the name of a temporary file in the specified directory
1854 using a prefix. The file is guaranteed not to exist at the time
1855 the function was called, but such guarantees are good for one
1856 clock tick only. Always use the proper form of C<sysopen>
1857 with C<O_CREAT | O_EXCL> if you must open such a filename.
1859 $filename = File::Temp::tempnam( $dir, $prefix );
1861 Equivalent to running mktemp() with $dir/$prefixXXXXXXXX
1862 (using unix file convention as an example)
1864 Because this function uses mktemp(), it can suffer from race conditions.
1866 Will croak() if there is an error.
1872 croak 'Usage tempnam($dir, $prefix)' unless scalar(@_) == 2;
1874 my ($dir, $prefix) = @_;
1876 # Add a string to the prefix
1877 $prefix .= 'XXXXXXXX';
1879 # Concatenate the directory to the file
1880 my $template = File::Spec->catfile($dir, $prefix);
1882 return mktemp($template);
1888 =head1 UTILITY FUNCTIONS
1890 Useful functions for dealing with the filehandle and filename.
1896 Given an open filehandle and the associated filename, make a safe
1897 unlink. This is achieved by first checking that the filename and
1898 filehandle initially point to the same file and that the number of
1899 links to the file is 1 (all fields returned by stat() are compared).
1900 Then the filename is unlinked and the filehandle checked once again to
1901 verify that the number of links on that file is now 0. This is the
1902 closest you can come to making sure that the filename unlinked was the
1903 same as the file whose descriptor you hold.
1906 or die "Error unlinking file $path safely";
1908 Returns false on error but croaks() if there is a security
1909 anomaly. The filehandle is not closed since on some occasions this is
1912 On some platforms, for example Windows NT, it is not possible to
1913 unlink an open file (the file must be closed first). On those
1914 platforms, the actual unlinking is deferred until the program ends and
1915 good status is returned. A check is still performed to make sure that
1916 the filehandle and filename are pointing to the same thing (but not at
1917 the time the end block is executed since the deferred removal may not
1918 have access to the filehandle).
1920 Additionally, on Windows NT not all the fields returned by stat() can
1921 be compared. For example, the C<dev> and C<rdev> fields seem to be
1922 different. Also, it seems that the size of the file returned by stat()
1923 does not always agree, with C<stat(FH)> being more accurate than
1924 C<stat(filename)>, presumably because of caching issues even when
1925 using autoflush (this is usually overcome by waiting a while after
1926 writing to the tempfile before attempting to C<unlink0> it).
1928 Finally, on NFS file systems the link count of the file handle does
1929 not always go to zero immediately after unlinking. Currently, this
1930 command is expected to fail on NFS disks.
1932 This function is disabled if the global variable $KEEP_ALL is true
1933 and an unlink on open file is supported. If the unlink is to be deferred
1934 to the END block, the file is still registered for removal.
1936 This function should not be called if you are using the object oriented
1937 interface since the it will interfere with the object destructor deleting
1944 croak 'Usage: unlink0(filehandle, filename)'
1945 unless scalar(@_) == 2;
1948 my ($fh, $path) = @_;
1950 cmpstat($fh, $path) or return 0;
1952 # attempt remove the file (does not work on some platforms)
1953 if (_can_unlink_opened_file()) {
1955 # return early (Without unlink) if we have been instructed to retain files.
1956 return 1 if $KEEP_ALL;
1958 # XXX: do *not* call this on a directory; possible race
1959 # resulting in recursive removal
1960 croak "unlink0: $path has become a directory!" if -d $path;
1961 unlink($path) or return 0;
1963 # Stat the filehandle
1966 print "Link count = $fh[3] \n" if $DEBUG;
1968 # Make sure that the link count is zero
1969 # - Cygwin provides deferred unlinking, however,
1970 # on Win9x the link count remains 1
1971 # On NFS the link count may still be 1 but we cant know that
1973 return ( $fh[3] == 0 or $^O eq 'cygwin' ? 1 : 0);
1976 _deferred_unlink($fh, $path, 0);
1984 Compare C<stat> of filehandle with C<stat> of provided filename. This
1985 can be used to check that the filename and filehandle initially point
1986 to the same file and that the number of links to the file is 1 (all
1987 fields returned by stat() are compared).
1990 or die "Error comparing handle with file";
1992 Returns false if the stat information differs or if the link count is
1993 greater than 1. Calls croak if there is a security anomaly.
1995 On certain platforms, for example Windows, not all the fields returned by stat()
1996 can be compared. For example, the C<dev> and C<rdev> fields seem to be
1997 different in Windows. Also, it seems that the size of the file
1998 returned by stat() does not always agree, with C<stat(FH)> being more
1999 accurate than C<stat(filename)>, presumably because of caching issues
2000 even when using autoflush (this is usually overcome by waiting a while
2001 after writing to the tempfile before attempting to C<unlink0> it).
2003 Not exported by default.
2009 croak 'Usage: cmpstat(filehandle, filename)'
2010 unless scalar(@_) == 2;
2013 my ($fh, $path) = @_;
2015 warn "Comparing stat\n"
2018 # Stat the filehandle - which may be closed if someone has manually
2019 # closed the file. Can not turn off warnings without using $^W
2020 # unless we upgrade to 5.006 minimum requirement
2028 if ($fh[3] > 1 && $^W) {
2029 carp "unlink0: fstat found too many links; SB=@fh" if $^W;
2033 my @path = stat $path;
2036 carp "unlink0: $path is gone already" if $^W;
2040 # this is no longer a file, but may be a directory, or worse
2042 confess "panic: $path is no longer a file: SB=@fh";
2045 # Do comparison of each member of the array
2046 # On WinNT dev and rdev seem to be different
2047 # depending on whether it is a file or a handle.
2048 # Cannot simply compare all members of the stat return
2049 # Select the ones we can use
2050 my @okstat = (0..$#fh); # Use all by default
2051 if ($^O eq 'MSWin32') {
2052 @okstat = (1,2,3,4,5,7,8,9,10);
2053 } elsif ($^O eq 'os2') {
2054 @okstat = (0, 2..$#fh);
2055 } elsif ($^O eq 'VMS') { # device and file ID are sufficient
2057 } elsif ($^O eq 'dos') {
2058 @okstat = (0,2..7,11..$#fh);
2059 } elsif ($^O eq 'mpeix') {
2060 @okstat = (0..4,8..10);
2063 # Now compare each entry explicitly by number
2065 print "Comparing: $_ : $fh[$_] and $path[$_]\n" if $DEBUG;
2066 # Use eq rather than == since rdev, blksize, and blocks (6, 11,
2067 # and 12) will be '' on platforms that do not support them. This
2068 # is fine since we are only comparing integers.
2069 unless ($fh[$_] eq $path[$_]) {
2070 warn "Did not match $_ element of stat\n" if $DEBUG;
2080 Similar to C<unlink0> except after file comparison using cmpstat, the
2081 filehandle is closed prior to attempting to unlink the file. This
2082 allows the file to be removed without using an END block, but does
2083 mean that the post-unlink comparison of the filehandle state provided
2084 by C<unlink0> is not available.
2087 or die "Error closing and unlinking file";
2089 Usually called from the object destructor when using the OO interface.
2091 Not exported by default.
2093 This function is disabled if the global variable $KEEP_ALL is true.
2095 Can call croak() if there is a security anomaly during the stat()
2101 croak 'Usage: unlink1(filehandle, filename)'
2102 unless scalar(@_) == 2;
2105 my ($fh, $path) = @_;
2107 cmpstat($fh, $path) or return 0;
2110 close( $fh ) or return 0;
2112 # Make sure the file is writable (for windows)
2113 _force_writable( $path );
2115 # return early (without unlink) if we have been instructed to retain files.
2116 return 1 if $KEEP_ALL;
2119 return unlink($path);
2124 Calling this function will cause any temp files or temp directories
2125 that are registered for removal to be removed. This happens automatically
2126 when the process exits but can be triggered manually if the caller is sure
2127 that none of the temp files are required. This method can be registered as
2130 On OSes where temp files are automatically removed when the temp file
2131 is closed, calling this function will have no effect other than to remove
2132 temporary directories (which may include temporary files).
2134 File::Temp::cleanup();
2136 Not exported by default.
2140 =head1 PACKAGE VARIABLES
2142 These functions control the global state of the package.
2148 Controls the lengths to which the module will go to check the safety of the
2149 temporary file or directory before proceeding.
2156 Do the basic security measures to ensure the directory exists and is
2157 writable, that temporary files are opened only if they do not already
2158 exist, and that possible race conditions are avoided. Finally the
2159 L<unlink0|"unlink0"> function is used to remove files safely.
2163 In addition to the STANDARD security, the output directory is checked
2164 to make sure that it is owned either by root or the user running the
2165 program. If the directory is writable by group or by other, it is then
2166 checked to make sure that the sticky bit is set.
2168 Will not work on platforms that do not support the C<-k> test
2173 In addition to the MEDIUM security checks, also check for the
2174 possibility of ``chown() giveaway'' using the L<POSIX|POSIX>
2175 sysconf() function. If this is a possibility, each directory in the
2176 path is checked in turn for safeness, recursively walking back to the
2179 For platforms that do not support the L<POSIX|POSIX>
2180 C<_PC_CHOWN_RESTRICTED> symbol (for example, Windows NT) it is
2181 assumed that ``chown() giveaway'' is possible and the recursive test
2186 The level can be changed as follows:
2188 File::Temp->safe_level( File::Temp::HIGH );
2190 The level constants are not exported by the module.
2192 Currently, you must be running at least perl v5.6.0 in order to
2193 run with MEDIUM or HIGH security. This is simply because the
2194 safety tests use functions from L<Fcntl|Fcntl> that are not
2195 available in older versions of perl. The problem is that the version
2196 number for Fcntl is the same in perl 5.6.0 and in 5.005_03 even though
2197 they are different versions.
2199 On systems that do not support the HIGH or MEDIUM safety levels
2200 (for example Win NT or OS/2) any attempt to change the level will
2201 be ignored. The decision to ignore rather than raise an exception
2202 allows portable programs to be written with high security in mind
2203 for the systems that can support this without those programs failing
2204 on systems where the extra tests are irrelevant.
2206 If you really need to see whether the change has been accepted
2207 simply examine the return value of C<safe_level>.
2209 $newlevel = File::Temp->safe_level( File::Temp::HIGH );
2210 die "Could not change to high security"
2211 if $newlevel != File::Temp::HIGH;
2216 # protect from using the variable itself
2217 my $LEVEL = STANDARD;
2222 if (($level != STANDARD) && ($level != MEDIUM) && ($level != HIGH)) {
2223 carp "safe_level: Specified level ($level) not STANDARD, MEDIUM or HIGH - ignoring\n" if $^W;
2225 # Dont allow this on perl 5.005 or earlier
2226 if ($] < 5.006 && $level != STANDARD) {
2227 # Cant do MEDIUM or HIGH checks
2228 croak "Currently requires perl 5.006 or newer to do the safe checks";
2230 # Check that we are allowed to change level
2231 # Silently ignore if we can not.
2232 $LEVEL = $level if _can_do_level($level);
2241 This is the highest UID on the current system that refers to a root
2242 UID. This is used to make sure that the temporary directory is
2243 owned by a system UID (C<root>, C<bin>, C<sys> etc) rather than
2246 This is required since on many unix systems C</tmp> is not owned
2249 Default is to assume that any UID less than or equal to 10 is a root
2252 File::Temp->top_system_uid(10);
2253 my $topid = File::Temp->top_system_uid;
2255 This value can be adjusted to reduce security checking if required.
2256 The value is only relevant when C<safe_level> is set to MEDIUM or higher.
2261 my $TopSystemUID = 10;
2262 $TopSystemUID = 197108 if $^O eq 'interix'; # "Administrator"
2263 sub top_system_uid {
2267 croak "top_system_uid: UIDs should be numeric"
2268 unless $newuid =~ /^\d+$/s;
2269 $TopSystemUID = $newuid;
2271 return $TopSystemUID;
2277 Controls whether temporary files and directories should be retained
2278 regardless of any instructions in the program to remove them
2279 automatically. This is useful for debugging but should not be used in
2282 $File::Temp::KEEP_ALL = 1;
2284 Default is for files to be removed as requested by the caller.
2286 In some cases, files will only be retained if this variable is true
2287 when the file is created. This means that you can not create a temporary
2288 file, set this variable and expect the temp file to still be around
2289 when the program exits.
2293 Controls whether debugging messages should be enabled.
2295 $File::Temp::DEBUG = 1;
2297 Default is for debugging mode to be disabled.
2303 For maximum security, endeavour always to avoid ever looking at,
2304 touching, or even imputing the existence of the filename. You do not
2305 know that that filename is connected to the same file as the handle
2306 you have, and attempts to check this can only trigger more race
2307 conditions. It's far more secure to use the filehandle alone and
2308 dispense with the filename altogether.
2310 If you need to pass the handle to something that expects a filename
2311 then, on a unix system, use C<"/dev/fd/" . fileno($fh)> for arbitrary
2312 programs, or more generally C<< "+<=&" . fileno($fh) >> for Perl
2313 programs. You will have to clear the close-on-exec bit on that file
2314 descriptor before passing it to another process.
2316 use Fcntl qw/F_SETFD F_GETFD/;
2317 fcntl($tmpfh, F_SETFD, 0)
2318 or die "Can't clear close-on-exec flag on temp fh: $!\n";
2320 =head2 Temporary files and NFS
2322 Some problems are associated with using temporary files that reside
2323 on NFS file systems and it is recommended that a local filesystem
2324 is used whenever possible. Some of the security tests will most probably
2325 fail when the temp file is not local. Additionally, be aware that
2326 the performance of I/O operations over NFS will not be as good as for
2331 In some cases files created by File::Temp are removed from within an
2332 END block. Since END blocks are triggered when a child process exits
2333 (unless C<POSIX::_exit()> is used by the child) File::Temp takes care
2334 to only remove those temp files created by a particular process ID. This
2335 means that a child will not attempt to remove temp files created by the
2338 If you are forking many processes in parallel that are all creating
2339 temporary files, you may need to reset the random number seed using
2340 srand(EXPR) in each child else all the children will attempt to walk
2341 through the same set of random file names and may well cause
2342 themselves to give up if they exceed the number of retry attempts.
2346 The file returned by File::Temp will have been opened in binary mode
2347 if such a mode is available. If that is not correct, use the C<binmode()>
2348 function to change the mode of the filehandle.
2350 Note that you can modify the encoding of a file opened by File::Temp
2351 also by using C<binmode()>.
2355 Originally began life in May 1999 as an XS interface to the system
2356 mkstemp() function. In March 2000, the OpenBSD mkstemp() code was
2357 translated to Perl for total control of the code's
2358 security checking, to ensure the presence of the function regardless of
2359 operating system and to help with portability. The module was shipped
2360 as a standard part of perl from v5.6.1.
2364 L<POSIX/tmpnam>, L<POSIX/tmpfile>, L<File::Spec>, L<File::Path>
2366 See L<IO::File> and L<File::MkTemp>, L<Apache::TempFile> for
2367 different implementations of temporary file handling.
2369 See L<File::Tempdir> for an alternative object-oriented wrapper for
2370 the C<tempdir> function.
2374 Tim Jenness E<lt>tjenness@cpan.orgE<gt>
2376 Copyright (C) 2007 Tim Jenness.
2377 Copyright (C) 1999-2007 Tim Jenness and the UK Particle Physics and
2378 Astronomy Research Council. All Rights Reserved. This program is free
2379 software; you can redistribute it and/or modify it under the same
2380 terms as Perl itself.
2382 Original Perl implementation loosely based on the OpenBSD C code for
2383 mkstemp(). Thanks to Tom Christiansen for suggesting that this module
2384 should be written and providing ideas for code improvements and
2385 security enhancements.
2389 package File::Temp::Dir;
2391 use File::Path qw/ rmtree /;
2393 use overload '""' => "STRINGIFY", fallback => 1;
2395 # private class specifically to support tempdir objects
2396 # created by File::Temp->newdir
2398 # ostensibly the same method interface as File::Temp but without
2399 # inheriting all the IO::Seekable methods and other cruft
2401 # Read-only - returns the name of the temp directory
2405 return $self->{DIRNAME};
2410 return $self->dirname;
2413 sub unlink_on_destroy {
2416 $self->{CLEANUP} = shift;
2418 return $self->{CLEANUP};
2423 if ($self->unlink_on_destroy &&
2424 $$ == $self->{LAUNCHPID} && !$File::Temp::KEEP_ALL) {
2425 rmtree($self->{DIRNAME}, $File::Temp::DEBUG, 0)
2426 if -d $self->{DIRNAME};