package File::Temp; =head1 NAME File::Temp - return name and handle of a temporary file safely =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 reliable? By default all the return values from C 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 C fails then the C 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 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"; $tmp->seek( 0, SEEK_END ); The following interfaces are provided for compatibility with existing APIs. They should not be used in new code. MkTemp family: use File::Temp qw/ :mktemp /; ($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 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 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. =cut # 5.6.0 gives us S_IWOTH, S_IWGRP, our and auto-vivifying filehandls # People would like a version on 5.004 so give them what they want :-) use 5.004; use strict; use Carp; use File::Spec 0.8; use File::Path qw/ rmtree /; use Fcntl 1.03; use IO::Seekable; # For SEEK_* use Errno; 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 $] < 5.006; ### For the OO interface use base qw/ IO::Handle IO::Seekable /; use overload '""' => "STRINGIFY", fallback => 1; # use 'our' on v5.6.0 use vars qw($VERSION @EXPORT_OK %EXPORT_TAGS $DEBUG $KEEP_ALL); $DEBUG = 0; $KEEP_ALL = 0; # We are exporting functions use base qw/Exporter/; # Export list - to allow fine tuning of export table @EXPORT_OK = qw{ tempfile tempdir tmpnam tmpfile mktemp mkstemp mkstemps mkdtemp unlink0 cleanup SEEK_SET SEEK_CUR SEEK_END }; # Groups of functions for export %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'); # Version number $VERSION = '0.22'; # 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 true. # 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" => 1, "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 principal 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 occassionally # 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( $chown_restricted ); } # To reach this point either, the _PC_CHOWN_RESTRICTED symbol # was not avialable or the symbol was there but chown giveaway # is allowed. Either way, we now have to test the entire tree for # safety. # Convert path to an absolute directory if required unless (File::Spec->file_name_is_absolute($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,$err_ref); } return 1; } # internal routine to determine whether unlink works on this # platform for files that are currently open. # Returns true if we can, false otherwise. # Currently WinNT, OS/2 and VMS can not unlink an opened file # On VMS this is because the O_EXCL flag is used to open the # temporary file. Currently I do not know enough about the issues # on VMS to decide whether O_EXCL is a requirement. sub _can_unlink_opened_file { if ($^O eq 'MSWin32' || $^O eq 'os2' || $^O eq 'VMS' || $^O eq 'dos' || $^O eq 'MacOS') { 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, $isdir ); # # - filehandle (so that it can be expclicitly closed if open # - filename (the thing we want to remove) # - isdir (flag to indicate that we are being given a directory) # [and hence no filehandle] # Status is not referred to since all the magic is done with an END block { # Will set up two lexical variables to contain all the files to be # removed. One array for files, another for directories They will # only exist in this block. # This means we only have to set up a single END block to remove # all files. # in order to prevent child processes inadvertently deleting the parent # temp files we use a hash to store the temp files and directories # created by a particular process id. # %files_to_unlink contains values that are references to an array of # array references containing the filehandle and filename associated with # the temp file. my (%files_to_unlink, %dirs_to_unlink); # Set up an end block to use these arrays END { local($., $@, $!, $^E, $?); cleanup(); } # Cleanup function. Always triggered on END but can be invoked # manually. sub cleanup { if (!$KEEP_ALL) { # Files my @files = (exists $files_to_unlink{$$} ? @{ $files_to_unlink{$$} } : () ); foreach my $file (@files) { # close the filehandle without checking its state # in order to make real sure that this is closed # if its already closed then I dont care about the answer # probably a better way to do this close($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{$$} ? @{ $dirs_to_unlink{$$} } : () ); foreach my $dir (@dirs) { if (-d $dir) { # Some versions of rmtree will abort if you attempt to remove # the directory you are sitting in. We protect that and turn it # into a warning. We do this because this occurs during # cleanup and so can not be caught by the user. eval { rmtree($dir, $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 $DEBUG; # If we have a directory, check that it is a directory if ($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; } } } } =head1 OBJECT-ORIENTED INTERFACE This is the primary interface for interacting with C. 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 object. The object itself acts as a filehandle. Also, the object is configured such that it stringifies to the name of the temporary file, and can be compared to a filename directly. The object isa C and isa C so all those methods are available. =over 4 =item B Create a temporary file object. my $tmp = File::Temp->new(); by default the object is constructed as if C 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: 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. =cut sub new { my $proto = shift; my $class = ref($proto) || $proto; # read arguments and convert keys to upper case my %args = @_; %args = map { uc($_), $args{$_} } keys %args; # see if they are unlinking (defaulting to yes) my $unlink = (exists $args{UNLINK} ? $args{UNLINK} : 1 ); delete $args{UNLINK}; # template (store it in an array so that it will # disappear from the arg list of tempfile) my @template = ( exists $args{TEMPLATE} ? $args{TEMPLATE} : () ); delete $args{TEMPLATE}; # Protect OPEN delete $args{OPEN}; # Open the file and retain file handle and file name my ($fh, $path) = tempfile( @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{$$}{$path} = 1; # Store unlink information in hash slot (plus other constructor info) %{*$fh} = %args; # create the object bless $fh, $class; # final method-based configuration $fh->unlink_on_destroy( $unlink ); return $fh; } =item B Create a temporary directory using an object oriented interface. $dir = File::Temp->newdir(); By default the directory is deleted when the object goes out of scope. Supports the same options as the C function. Note that directories created with this method default to CLEANUP => 1. $dir = File::Temp->newdir( $template, %options ); =cut sub newdir { my $self = shift; # need to handle args as in tempdir because we have to force CLEANUP # default without passing CLEANUP to tempdir my $template = (scalar(@_) % 2 == 1 ? shift(@_) : undef ); my %options = @_; my $cleanup = (exists $options{CLEANUP} ? $options{CLEANUP} : 1 ); delete $options{CLEANUP}; my $tempdir; if (defined $template) { $tempdir = tempdir( $template, %options ); } else { $tempdir = tempdir( %options ); } return bless { DIRNAME => $tempdir, CLEANUP => $cleanup, LAUNCHPID => $$, }, "File::Temp::Dir"; } =item B 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. =cut sub filename { my $self = shift; return ${*$self}; } sub STRINGIFY { my $self = shift; return $self->filename; } =item B 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 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. =cut sub unlink_on_destroy { my $self = shift; if (@_) { ${*$self}{UNLINK} = shift; } return ${*$self}{UNLINK}; } =item B When the object goes out of scope, the destructor is called. This destructor will attempt to unlink the file (using C) 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 was modified after creation. If the global variable $KEEP_ALL is true, the file or directory will not be removed. =cut sub DESTROY { local($., $@, $!, $^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); } } =back =head1 FUNCTIONS This section describes the recommended interface for generating temporary files and directories. =over 4 =item B This is the basic function to generate temporary files. The behaviour of the file can be changed using various options: $fh = tempfile(); ($fh, $filename) = tempfile(); Create a temporary file in the directory specified for temporary files, as specified by the tmpdir() function in L. ($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) 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 flag) the file is marked for deletion when the program ends (equivalent to setting UNLINK to 1). The C 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. If the operating system supports it (for example BSD derived systems), the filehandle will be opened with O_EXLOCK (open with exclusive file lock). This can sometimes cause problems if the intention is to pass the filename to another system that expects to take an exclusive lock itself (such as DBD::SQLite) whilst ensuring that the tempfile is not reused. In this situation the "EXLOCK" option can be passed to tempfile. By default EXLOCK will be true (this retains compatibility with earlier releases). ($fh, $filename) = tempfile($template, EXLOCK => 0); Options can be combined as required. Will croak() if there is an error. =cut sub tempfile { # 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" => 1, # Open file with O_EXLOCK ); # Check to see whether we have an odd or even number of arguments my $template = (scalar(@_) % 2 == 1 ? shift(@_) : undef); # Read the options and merge with defaults %options = (%options, @_) if @_; # 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(File::Spec->tmpdir, $template ); } } else { if ($options{"DIR"}) { $template = File::Spec->catfile($options{"DIR"}, TEMPXXX); } else { $template = File::Spec->catfile(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: $errstr" unless (($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; } } =item B 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). $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 option is ignored if C is set explicitly. Additionally, C 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 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. =cut # ' sub tempdir { # 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 $template = (scalar(@_) % 2 == 1 ? shift(@_) : undef ); # Read the options and merge with defaults %options = (%options, @_) if @_; # 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(File::Spec->tmpdir, $template); } } } else { if ($options{"DIR"}) { $template = File::Spec->catdir($options{"DIR"}, TEMPXXX); } else { $template = File::Spec->catdir(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 $tempdir; } =back =head1 MKTEMP FUNCTIONS The following functions are Perl implementations of the mktemp() family of temp file generation system calls. =over 4 =item B Given a template, returns a filehandle to the temporary file and the name of the file. ($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. The trailing X's are replaced with unique alphanumeric combinations. Will croak() if there is an error. =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 $fh; } } =item B Similar to mkstemp(), except that an extra argument can be supplied with a suffix to be appended to the template. ($fh, $name) = mkstemps( $template, $suffix ); For example a template of C and suffix of C<.dat> would generate a file similar to F. Returns just the filehandle alone when called in scalar context. Will croak() if there is an error. =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; } } =item B 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. =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; } =item B 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. =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; } =back =head1 POSIX FUNCTIONS This section describes the re-implementation of the tmpnam() and tmpfile() functions described in L using the mkstemp() from this module. Unlike the L implementations, the directory used for the temporary file is not specified in a system include file (C) but simply depends on the choice of tmpdir() returned by L. On some implementations this location can be set using the C environment variable, which may not be secure. If this is a problem, simply use mkstemp() and specify a template. =over 4 =item B 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 for information on the choice of temporary directory for a particular operating system. Will croak() if there is an error. =cut sub tmpnam { # Retrieve the temporary directory name my $tmpdir = File::Spec->tmpdir; 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); } } =item B Returns the filehandle of a temporary file. $fh = tmpfile(); The file is removed when the filehandle is closed or when the program exits. No access to the filename is provided. If the temporary file can not be created undef is returned. Currently this command will probably not work when the temporary directory is on an NFS file system. Will croak() if there is an error. =cut sub tmpfile { # Simply call tmpnam() in a list context my ($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; } =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 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 with C 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. =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); } =back =head1 UTILITY FUNCTIONS Useful functions for dealing with the filehandle and filename. =over 4 =item B 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 and C fields seem to be different. Also, it seems that the size of the file returned by stat() does not always agree, with C being more accurate than C, 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 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 $KEEP_ALL is true and an unlink on open file is supported. If the unlink is to be deferred to the END block, the file is still registered for removal. This function should not be called if you are using the object oriented interface since the it will interfere with the object destructor deleting the file. =cut sub unlink0 { croak 'Usage: unlink0(filehandle, filename)' unless scalar(@_) == 2; # Read args my ($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 cant know that # we are on NFS return ( $fh[3] == 0 or $^O eq 'cygwin' ? 1 : 0); } else { _deferred_unlink($fh, $path, 0); return 1; } } =item B Compare C of filehandle with C of provided filename. This can be used to check that the filename and filehandle initially point to the same file and that the number of links to the file is 1 (all fields returned by stat() are compared). cmpstat($fh, $path) or die "Error comparing handle with file"; Returns false if the stat information differs or if the link count is greater than 1. Calls croak if there is a security anomaly. On certain platforms, for example Windows, not all the fields returned by stat() can be compared. For example, the C and C fields seem to be different in Windows. Also, it seems that the size of the file returned by stat() does not always agree, with C being more accurate than C, presumably because of caching issues even when using autoflush (this is usually overcome by waiting a while after writing to the tempfile before attempting to C it). Not exported by default. =cut sub cmpstat { croak 'Usage: cmpstat(filehandle, filename)' unless scalar(@_) == 2; # Read args my ($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 $DEBUG; return 0; } } return 1; } =item B Similar to C except after file comparison using cmpstat, the filehandle is closed prior to attempting to unlink the file. This allows the file to be removed without using an END block, but does mean that the post-unlink comparison of the filehandle state provided by C is not available. unlink1($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 $KEEP_ALL is true. Can call croak() if there is a security anomaly during the stat() comparison. =cut sub unlink1 { croak 'Usage: unlink1(filehandle, filename)' unless scalar(@_) == 2; # Read args my ($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); } =item B 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. 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. =back =head1 PACKAGE VARIABLES These functions control the global state of the package. =over 4 =item B 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 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 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 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 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. $newlevel = File::Temp->safe_level( File::Temp::HIGH ); die "Could not change to high security" if $newlevel != File::Temp::HIGH; =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 $^W; } else { # Dont allow this on perl 5.005 or earlier if ($] < 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; } } =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, C, C etc) rather than simply by root. This is required since on many unix systems C 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 is set to MEDIUM or higher. =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 $TopSystemUID; } } =item B<$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. $File::Temp::DEBUG = 1; Default is for debugging mode to be disabled. =back =head1 WARNING For maximum security, endeavour always to avoid ever looking at, touching, or even imputing the existence of the filename. You do not know that that filename is connected to the same file as the handle you have, and attempts to check this can only trigger more race conditions. It's far more secure to use the filehandle alone and dispense with the filename altogether. If you need to pass the handle to something that expects a filename then, on a unix system, use C<"/dev/fd/" . fileno($fh)> for arbitrary programs, or more generally C<< "+<=&" . fileno($fh) >> for Perl programs. You will have to clear the close-on-exec bit on that file descriptor before passing it to another process. use Fcntl qw/F_SETFD F_GETFD/; fcntl($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 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 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 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. =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. =head1 SEE ALSO L, L, L, L See L and L, L for different implementations of temporary file handling. See L for an alternative object-oriented wrapper for the C function. =head1 AUTHOR Tim Jenness Etjenness@cpan.orgE Copyright (C) 2007-2009 Tim Jenness. Copyright (C) 1999-2007 Tim Jenness and the UK Particle Physics and Astronomy Research Council. All Rights Reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. Original Perl implementation loosely based on the OpenBSD C code for mkstemp(). Thanks to Tom Christiansen for suggesting that this module should be written and providing ideas for code improvements and security enhancements. =cut package File::Temp::Dir; use File::Path qw/ rmtree /; use strict; use overload '""' => "STRINGIFY", 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 $self->{DIRNAME}) { # Some versions of rmtree will abort if you attempt to remove # the directory you are sitting in. We protect that and turn it # into a warning. We do this because this occurs during object # destruction and so can not be caught by the user. eval { rmtree($self->{DIRNAME}, $File::Temp::DEBUG, 0); }; warn $@ if ($@ && $^W); } } } 1;