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| -rw-r--r-- | gnu/usr.bin/perl/lib/File/Temp.pm | 1458 |
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diff --git a/gnu/usr.bin/perl/lib/File/Temp.pm b/gnu/usr.bin/perl/lib/File/Temp.pm new file mode 100644 index 00000000000..e96fd298d32 --- /dev/null +++ b/gnu/usr.bin/perl/lib/File/Temp.pm @@ -0,0 +1,1458 @@ +package File::Temp; + +=head1 NAME + +File::Temp - return name and handle of a temporary file safely + +=head1 SYNOPSIS + + use File::Temp qw/ tempfile tempdir /; + + $dir = tempdir( CLEANUP => 1 ); + ($fh, $filename) = tempfile( DIR => $dir ); + + ($fh, $filename) = tempfile( $template, DIR => $dir); + ($fh, $filename) = tempfile( $template, SUFFIX => '.dat'); + + $fh = tempfile(); + +MkTemp family: + + use File::Temp qw/ :mktemp /; + + ($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, $file) = tmpnam(); + ($fh, $file) = tmpfile(); + + +Compatibility functions: + + $unopened_file = File::Temp::tempnam( $dir, $pfx ); + +=begin later + +Objects (NOT YET IMPLEMENTED): + + require File::Temp; + + $fh = new File::Temp($template); + $fname = $fh->filename; + +=end later + +=head1 DESCRIPTION + +C<File::Temp> can be used to create and open temporary files in a safe way. +The tempfile() function can be used to return the name and the open +filehandle of a temporary file. The tempdir() function can +be used to create a temporary directory. + +The security aspect of temporary file creation is emphasized such that +a filehandle and filename are returned together. This helps guarantee that +a race condition can not occur where the temporary file is created by another process +between checking for the existence of the file and its +opening. Additional security levels are provided to check, for +example, that the sticky bit is set on world writable directories. +See L<"safe_level"> for more information. + +For compatibility with popular C library functions, Perl implementations of +the mkstemp() family of functions are provided. These are, mkstemp(), +mkstemps(), mkdtemp() and mktemp(). + +Additionally, implementations of the standard L<POSIX|POSIX> +tmpnam() and tmpfile() functions are provided if required. + +Implementations of mktemp(), tmpnam(), and tempnam() are provided, +but should be used with caution since they return only a filename +that was valid when function was called, so cannot guarantee +that the file will not exist by the time the caller opens the filename. + +=cut + +use v5.5.670; # Uses S_IWOTH in Fcntl and auto-viv filehandles, new File::Spec +use strict; +use Carp; +use File::Spec 0.8; +use File::Path qw/ rmtree /; +use Fcntl 1.03 qw/ :DEFAULT S_IWOTH S_IWGRP /; +use Errno qw( EEXIST ENOENT ENOTDIR EINVAL ); + +our ($VERSION, @EXPORT_OK, %EXPORT_TAGS, $DEBUG); + +$DEBUG = 0; + +# We are exporting functions + +#require Exporter; +#@ISA = qw/Exporter/; +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 + }; + +# Groups of functions for export + +%EXPORT_TAGS = ( + 'POSIX' => [qw/ tmpnam tmpfile /], + 'mktemp' => [qw/ mktemp mkstemp mkstemps mkdtemp/], + ); + +# add contents of these tags to @EXPORT +Exporter::export_tags('POSIX','mktemp'); + +# Version number + +$VERSION = '0.05'; + +# This is a list of characters that can be used in random filenames + +my @CHARS = (qw/ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z + a b c d e f g h i j k l m n o p q r s t u v w x y z + 0 1 2 3 4 5 6 7 8 9 _ + /); + +# Maximum number of tries to make a temp file before failing + +use constant MAX_TRIES => 10; + +# Minimum number of X characters that should be in a template +use constant MINX => 4; + +# Default template when no template supplied + +use constant TEMPXXX => 'X' x 10; + +# Constants for the security level + +use constant STANDARD => 0; +use constant MEDIUM => 1; +use constant HIGH => 2; + +# INTERNAL ROUTINES - not to be used outside of package + +# Generic routine for getting a temporary filename +# modelled on OpenBSD _gettemp() in mktemp.c + +# The template must contain X's that are to be replaced +# with the random values + +# Arguments: + +# TEMPLATE - string containing the XXXXX's that is converted +# to a random filename and opened if required + +# Optionally, a hash can also be supplied containing specific options +# "open" => if true open the temp file, else just return the name +# default is 0 +# "mkdir"=> if true, we are creating a temp directory rather than tempfile +# default is 0 +# "suffixlen" => number of characters at end of PATH to be ignored. +# default is 0. +# "open" and "mkdir" can not both be true + +# The default options are equivalent to mktemp(). + +# Returns: +# filehandle - open file handle (if called with doopen=1, else undef) +# temp name - name of the temp file or directory + +# For example: +# ($fh, $name) = _gettemp($template, "open" => 1); + +# for the current version, failures are associated with +# a carp to give the reason whilst debugging + +sub _gettemp { + + croak 'Usage: ($fh, $name) = _gettemp($template, OPTIONS);' + unless scalar(@_) >= 1; + + # Default options + my %options = ( + "open" => 0, + "mkdir" => 0, + "suffixlen" => 0, + ); + + # Read the template + my $template = shift; + if (ref($template)) { + 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) { + carp "File::Temp::_gettemp: Must have even number of options"; + return (); + } + + # Read the options and merge with defaults + %options = (%options, @_) if @_; + + # Can not open the file and make a directory in a single call + if ($options{"open"} && $options{"mkdir"}) { + carp "File::Temp::_gettemp: 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 - $options{"suffixlen"}; + + # Check that we have at least MINX x X (eg 'XXXX") at the end of the string + # (taking suffixlen into account). Any fewer is insecure. + + # Do it using substr - no reason to use a pattern match since + # we know where we are looking and what we are looking for + + if (substr($template, $start - MINX + 1, MINX) ne 'X' x MINX) { + carp "File::Temp::_gettemp: The template must contain 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 that means we are in the current + # directory + if ($#dirs == 0) { + $parent = File::Spec->curdir; + } 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 (-d $parent && -w _) { + carp "File::Temp::_gettemp: Parent directory ($parent) is not a directory" + . " or is not writable\n"; + 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) { + unless (_is_safe($parent)) { + carp "File::Temp::_gettemp: Parent directory ($parent) is not safe (sticky bit not set when world writable?)"; + return (); + } + } elsif (File::Temp->safe_level == HIGH) { + unless (_is_verysafe($parent)) { + carp "File::Temp::_gettemp: Parent directory ($parent) is not safe (sticky bit not set when world writable?)"; + return (); + } + } + + + # Calculate the flags that we wish to use for the sysopen + # Some of these are not always available + my $openflags; + if ($options{"open"}) { + # Default set + $openflags = O_CREAT | O_EXCL | O_RDWR; + + # Add the remainder as available + $openflags |= Fcntl::O_FOLLOW() + if eval { Fcntl::O_FOLLOW(); 1 }; + + $openflags |= Fcntl::O_BINARY() + if eval { Fcntl::O_BINARY(); 1 }; + + $openflags |= Fcntl::O_LARGEFILE() + if eval { Fcntl::O_LARGEFILE(); 1 }; + + $openflags |= Fcntl::O_EXLOCK() + if eval { Fcntl::O_EXLOCK(); 1 }; + + } + + + # 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; + + # 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 is not in Fcntl.pm, though. + local $^F = 2; + + # Store callers umask + my $umask = umask(); + + # Set a known umask + umask(066); + + # Attempt to open the file + if ( sysopen($fh, $path, $openflags, 0600) ) { + + # Reset umask + umask($umask); + + # Opened successfully - return file handle and name + return ($fh, $path); + + } else { + # Reset umask + umask($umask); + + # Error opening file - abort with error + # if the reason was anything but EEXIST + unless ($! == EEXIST) { + carp "File::Temp: Could not create temp file $path: $!"; + return (); + } + + # Loop round for another try + + } + } elsif ($options{"mkdir"}) { + + # Store callers umask + my $umask = umask(); + + # Set a known umask + umask(066); + + # Open the temp directory + if (mkdir( $path, 0700)) { + # created okay + # Reset umask + umask($umask); + + return undef, $path; + } else { + + # Reset umask + umask($umask); + + # Abort with error if the reason for failure was anything + # except EEXIST + unless ($! == EEXIST) { + carp "File::Temp: 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 > $MAX_GUESS) { + carp "Tried to get a new temp name different to the previous value$MAX_GUESS times.\nSomething wrong with template?? ($template)"; + return (); + } + + } + + # If we get here, we have run out of tries + carp "Have exceeded the maximum number of attempts (".MAX_TRIES . + ") to open temp file/dir"; + + return (); + +} + +# Internal routine to return a random character from the +# character list. Does not do an srand() since rand() +# will do one automatically + +# No arguments. Return value is the random character + +sub _randchar { + + $CHARS[ int( rand( $#CHARS ) ) ]; + +} + +# 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. + + if ($ignore) { + substr($path, 0, - $ignore) =~ s/X(?=X*\z)/_randchar()/ge; + } else { + $path =~ s/X(?=X*\z)/_randchar()/ge; + } + + return $path; +} + +# 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 +# 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 $path = shift; + + # Stat path + my @info = stat($path); + return 0 unless scalar(@info); + + # Check to see whether owner is neither superuser (or a system uid) nor me + # Use the real uid from the $< variable + # UID is in [4] + if ( $info[4] > File::Temp->top_system_uid() && $info[4] != $<) { + carp "Directory owned neither by root nor the current user"; + return 0; + } + + # check whether group or other can write file + # use 066 to detect either reading or writing + # use 022 to check writability + # Do it with S_IWOTH and S_IWGRP for portability (maybe) + # mode is in info[2] + if (($info[2] & S_IWGRP) || # Is group writable? + ($info[2] & S_IWOTH) ) { # Is world writable? + return 0 unless -d _; # Must be a directory + return 0 unless -k _; # Must be sticky + } + + 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. + +sub _is_verysafe { + + # Need POSIX - but only want to bother if really necessary due to overhead + require POSIX; + + my $path = shift; + + # Should Get the value of _PC_CHOWN_RESTRICTED if it is defined + # and If it is not there do the extensive test + + # Check for chown giveaway + # Might want to do the directory splitting anyway + return _is_safe($path) if POSIX::sysconf( &POSIX::_PC_CHOWN_RESTRICTED); + + # 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( $path, 1); + + # Slightly less efficient than having a a function in File::Spec + # to chop off the end of a directory or even a function that + # can handle ../ in a directory tree + # Sometimes splitdir() returns a blank at the end + # so we will probably check the bottom directory twice in some cases + my @dirs = File::Spec->splitdir($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 $DEBUG; + + # Check the directory + return unless _is_safe($dir); + + } + + return 1; +} + + + +# internal routine to determine whether unlink works on this +# platform +# Returns true if we can, false otherwise. +# Simply uses $^O rather than creating a temp file and trying +# to delete it (the whole point of this module) +# Currently we are using rmtree() to do this since +# it can be supplied with a single file and knows about +# different platforms. + +# Currently does nothing since File::Path::rmtree can unlink +# on WinNT. + +sub _can_unlink { + + + $^O ne 'MSWin32' ? 1 : 1; + +} + + +=head1 FUNCTIONS + +This section describes the recommended interface for generating +temporary files and directories. + +=over 4 + +=item B<tempfile> + +This is the basic function to generate temporary files. +The behaviour of the file can be changed using various options: + + ($fh, $filename) = tempfile(); + +Create a temporary file in the directory specified for temporary +files, as specified by the tmpdir() function in L<File::Spec>. + + ($fh, $filename) = tempfile($template); + +Create a temporary file using the template. Trailing `X' characters +are replaced with random letters to generate the filename. +At least four `X' characters must be present in 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. + +If the template is not specified, a template is always +automatically generated. This temporary file is placed in tmpdir() +(L<File::Spec>) unless a directory is specified explicitly with the +DIR option. + + $fh = tempfile( $template, DIR => $dir ); + +If called in scalar context, only the filehandle is returned +and the file will automatically be deleted when closed (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. + + (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. + +=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, # Unlink file on exit + "OPEN" => 1, # Do not open file + ); + + # 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; + + } + + # 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 $template) { + if ($options{"DIR"}) { + + $template = File::Spec->catfile($options{"DIR"}, $template); + + } + + } else { + + if ($options{"DIR"}) { + + $template = File::Spec->catfile($options{"DIR"}, TEMPXXX); + + } else { + + $template = File::Spec->catfile(File::Spec->tmpdir, TEMPXXX); + + } + + } + + # Now add a suffix + $template .= $options{"SUFFIX"}; + + # Create the file + my ($fh, $path); + croak "Error in tempfile() using $template" + unless (($fh, $path) = _gettemp($template, + "open" => $options{'OPEN'}, + "mkdir"=> 0 , + "suffixlen" => length($options{'SUFFIX'}), + ) ); + + # Setup an exit handler + # Do not perform the safe unlink0 since the filehandle may be + # closed and be invalid + # Return status is not checked. + END { rmtree($path, $DEBUG, 1) if ($options{"UNLINK"} && -f $path); }; + + # Return + if (wantarray()) { + + if ($options{'OPEN'}) { + return ($fh, $path); + } else { + return (undef, $path); + } + + } else { + # Assume that we can unlink the file with unlink0 + # since the caller is not interested in the name + unlink0($fh, $path); + + # Return just the filehandle. + return $fh; + } + + +} + +=item B<tempdir> + +This is the recommended interface for creation of temporary directories. +The behaviour of the function depends on the arguments: + + $tempdir = tempdir(); + +Create a directory in tmpdir() (see L<File::Spec|File::Spec>). + + $tempdir = tempdir( $template ); + +Create a directory from the supplied template. This template is +similar to that described for tempfile(). `X' characters at the end +of the template are replaced with random letters to construct the +directory name. At least four `X' characters must be in the template. + + $tempdir = tempdir ( DIR => $dir ); + +Specifies the directory to use for the temporary directory. +The temporary directory name is derived from an internal template. + + $tempdir = tempdir ( $template, DIR => $dir ); + +Prepend the supplied directory name to the template. The template +should not include parent directory specifications itself. Any parent +directory specifications are removed from the template before +prepending the supplied directory. + + $tempdir = tempdir ( $template, TMPDIR => 1 ); + +Using the supplied template, creat the temporary directory in +a standard location for temporary files. Equivalent to doing + + $tempdir = tempdir ( $template, DIR => File::Spec->tmpdir); + +but shorter. Parent directory specifications are stripped from the +template itself. The C<TMPDIR> option is ignored if C<DIR> is set +explicitly. Additionally, C<TMPDIR> is implied if neither a template +nor a directory are supplied. + + $tempdir = tempdir( $template, CLEANUP => 1); + +Create a temporary directory using the supplied template, but +attempt to remove it (and all files inside it) when the program +exits. Note that an attempt will be made to remove all files from +the directory even if they were not created by this module (otherwise +why ask to clean it up?). The directory removal is made with +the rmtree() function from the L<File::Path|File::Path> module. +Of course, if the template is not specified, the temporary directory +will be created in tmpdir() and will also be removed at program exit. + +=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'} || $options{'DIR'}) { + + # Strip parent directory from the filename + # + # There is no filename at the end + my ($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"}) { + + $template = File::Spec->catfile($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; + croak "Error in tempdir() using $template" + unless ((undef, $tempdir) = _gettemp($template, + "open" => 0, + "mkdir"=> 1 , + "suffixlen" => 0, + ) ); + + # Install exit handler; must be dynamic to get lexical + if ( $options{'CLEANUP'} && -d $tempdir) { + eval q{ END { rmtree($tempdir,$DEBUG, 1) } 1; } || die; + } + + # Return the dir name + return $tempdir; + +} + +=back + +=head1 MKTEMP FUNCTIONS + +The following functions are Perl implementations of the +mktemp() family of temp file generation system calls. + +=over 4 + +=item B<mkstemp> + +Given a template, returns a filehandle to the temporary file and the name +of the file. + + ($fh, $name) = mkstemp( $template ); + +In scalar context, just the filehandle is returned. + +The template may be any filename with some number of X's appended +to it, for example F</tmp/temp.XXXX>. The trailing X's are replaced +with unique alphanumeric combinations. + +=cut + + + +sub mkstemp { + + croak "Usage: mkstemp(template)" + if scalar(@_) != 1; + + my $template = shift; + + my ($fh, $path); + croak "Error in mkstemp using $template" + unless (($fh, $path) = _gettemp($template, + "open" => 1, + "mkdir"=> 0 , + "suffixlen" => 0, + ) ); + + if (wantarray()) { + return ($fh, $path); + } else { + return $fh; + } + +} + + +=item B<mkstemps> + +Similar to mkstemp(), except that an extra argument can be supplied +with a suffix to be appended to the template. + + ($fh, $name) = mkstemps( $template, $suffix ); + +For example a template of C<testXXXXXX> and suffix of C<.dat> +would generate a file similar to F<testhGji_w.dat>. + +Returns just the filehandle alone when called in scalar context. + +=cut + +sub mkstemps { + + croak "Usage: mkstemps(template, suffix)" + if scalar(@_) != 2; + + + my $template = shift; + my $suffix = shift; + + $template .= $suffix; + + my ($fh, $path); + croak "Error in mkstemps using $template" + unless (($fh, $path) = _gettemp($template, + "open" => 1, + "mkdir"=> 0 , + "suffixlen" => length($suffix), + ) ); + + if (wantarray()) { + return ($fh, $path); + } else { + return $fh; + } + +} + +=item B<mkdtemp> + +Create a directory from a template. The template must end in +X's that are replaced by the routine. + + $tmpdir_name = mkdtemp($template); + +Returns the name of the temporary directory created. +Returns undef on failure. + +Directory must be removed by the caller. + +=cut + + + +sub mkdtemp { + + croak "Usage: mkdtemp(template)" + if scalar(@_) != 1; + + my $template = shift; + + my ($junk, $tmpdir); + croak "Error creating temp directory from template $template\n" + unless (($junk, $tmpdir) = _gettemp($template, + "open" => 0, + "mkdir"=> 1 , + "suffixlen" => 0, + ) ); + + return $tmpdir; + +} + +=item B<mktemp> + +Returns a valid temporary filename but does not guarantee +that the file will not be opened by someone else. + + $unopened_file = mktemp($template); + +Template is the same as that required by mkstemp(). + +=cut + +sub mktemp { + + croak "Usage: mktemp(template)" + if scalar(@_) != 1; + + my $template = shift; + + my ($tmpname, $junk); + croak "Error getting name to temp file from template $template\n" + unless (($junk, $tmpname) = _gettemp($template, + "open" => 0, + "mkdir"=> 0 , + "suffixlen" => 0, + ) ); + + return $tmpname; +} + +=back + +=head1 POSIX FUNCTIONS + +This section describes the re-implementation of the tmpnam() +and tmpfile() functions described in L<POSIX> +using the mkstemp() from this module. + +Unlike the L<POSIX|POSIX> implementations, the directory used +for the temporary file is not specified in a system include +file (C<P_tmpdir>) but simply depends on the choice of tmpdir() +returned by L<File::Spec|File::Spec>. On some implementations this +location can be set using the C<TMPDIR> environment variable, which +may not be secure. +If this is a problem, simply use mkstemp() and specify a template. + +=over 4 + +=item B<tmpnam> + +When called in scalar context, returns the full name (including path) +of a temporary file (uses mktemp()). The only check is that the file does +not already exist, but there's no guarantee that that condition will +continue to apply. + + $file = tmpnam(); + +When called in list context, a filehandle to the open file and +a filename are returned. This is achieved by calling mkstemp() +after constructing a suitable template. + + ($fh, $file) = tmpnam(); + +If possible, this form should be used to prevent possible +race conditions. + +See L<File::Spec/tmpdir> for information on the choice of temporary +directory for a particular operating system. + +=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<tmpfile> + +In scalar context, returns the filehandle of a temporary file. + + $fh = tmpfile(); + +The file is removed when the filehandle is closed or when the program +exits. No access to the filename is provided. + +=cut + +sub tmpfile { + + # Simply call tmpnam() in an array context + my ($fh, $file) = tmpnam(); + + # Make sure file is removed when filehandle is closed + unlink0($fh, $file) or croak "Unable to unlink temporary file: $!"; + + 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<tempnam> + +Return the name of a temporary file in the specified directory +using a prefix. The file is guaranteed not to exist at the time +the function was called, but such guarantees are good for one +clock tick only. Always use the proper form of C<sysopen> +with C<O_CREAT | O_EXCL> if you must open such a filename. + + $filename = File::Temp::tempnam( $dir, $prefix ); + +Equivalent to running mktemp() with $dir/$prefixXXXXXXXX +(using unix file convention as an example) + +Because this function uses mktemp(), it can suffer from race conditions. + +=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<unlink0> + +Given an open filehandle and the associated filename, make +a safe unlink. This is achieved by first checking that the filename +and filehandle initially point to the same file and that the number +of links to the file is 1. 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 $path safely"; + +Returns false on error. + +=cut + +sub unlink0 { + + croak 'Usage: unlink0(filehandle, filename)' + unless scalar(@_) == 2; + + # Read args + my ($fh, $path) = @_; + + # Might as well return immediately if we cant unlink + # But still return success though + unless (_can_unlink()) { + warn "File $path can not be unlinked on this platform" if $^W; + return 1; + } + + # Stat the filehandle + my @fh = stat $fh; + + if ($fh[3] > 1 && $^W) { + carp "unlink0: fstat found too many links; SB=@fh"; + } + + # 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 _) { + 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); + } + + # Now compare each entry explicitly by number + for (@okstat) { + # print "Comparing: $_ : $fh[$_] and $path[$_]\n"; + return 0 unless $fh[$_] == $path[$_]; + } + + # remove the file (does not work on some platforms) + # Test is done earlier anyway! + if (_can_unlink()) { +# unlink($path) or return 0; + # XXX: do *not* call this on a directory; possible race + # resulting in recursive removal + croak "unlink0: $path has become a directory!" if -d $path; + rmtree ($path, $DEBUG,1) or return 0; + } + + # Stat the filehandle + @fh = stat $fh; + + # Make sure that the link count is zero + return ( $fh[3] == 0 ? 1 : 0); + +} + +=back + +=head1 PACKAGE VARIABLES + +These functions control the global state of the package. + +=over 4 + +=item B<safe_level> + +Controls the lengths to which the module will go to check the safety of the +temporary file or directory before proceeding. +Options are: + +=over 8 + +=item STANDARD + +Do the basic security measures to ensure the directory exists and +is writable, that the umask() is fixed before opening of the file, +that temporary files are opened only if they do not already exist, and +that possible race conditions are avoided. Finally the L<unlink0|"unlink0"> +function is used to remove files safely. + +=item MEDIUM + +In addition to the STANDARD security, the output directory is checked +to make sure that it is owned either by root or the user running the +program. If the directory is writable by group or by other, it is then +checked to make sure that the sticky bit is set. + +Will not work on platforms that do not support the C<-k> test +for sticky bit. + +=item HIGH + +In addition to the MEDIUM security checks, also check for the +possibility of ``chown() giveaway'' using the L<POSIX|POSIX> +sysconf() function. If this is a possibility, each directory in the +path is checked in turn for safeness, recursively walking back to the +root directory. + +Will not work on platforms that do not support the L<POSIX|POSIX> +C<_PC_CHOWN_RESTRICTED> symbol (for example, Windows NT). + +=back + +The level can be changed as follows: + + File::Temp->safe_level( File::Temp::HIGH ); + +The level constants are not exported by the module. + +=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"; + } else { + $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<root>, C<bin>, C<sys> etc) rather than +simply by root. + +This is required since on many unix systems C</tmp> is not owned +by root. + +Default is to assume that any UID less than or equal to 10 is a root +UID. + + File::Temp->top_system_uid(10); + my $topid = File::Temp->top_system_uid; + +This value can be adjusted to reduce security checking if required. +The value is only relevant when C<safe_level> is set to MEDIUM or higher. + +=back + +=cut + +{ + my $TopSystemUID = 10; + 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 $TopSystemUID; + } +} + +=head1 WARNING + +For maximum security, endeavour always to avoid ever looking at, +touching, or even imputing the existence of the filename. You do not +know that that filename is connected to the same file as the handle +you have, and attempts to check this can only trigger more race +conditions. It's far more secure to use the filehandle alone and +dispense with the filename altogether. + +If you need to pass the handle to something that expects a filename +then, on a unix system, use C<"/dev/fd/" . fileno($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"; + +=head1 HISTORY + +Originally began life in May 1999 as an XS interface to the system +mkstemp() function. In March 2000, the 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. + +=head1 SEE ALSO + +L<POSIX/tmpnam>, L<POSIX/tmpfile>, L<File::Spec>, L<File::Path> + +See L<File::MkTemp> for a different implementation of temporary +file handling. + +=head1 AUTHOR + +Tim Jenness E<lt>t.jenness@jach.hawaii.eduE<gt> + +Copyright (C) 1999, 2000 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 + + +1; |