File::Temp - return name and handle of a temporary file safely
+=begin __INTERNALS
+
+=head1 PORTABILITY
+
+This module is designed to be portable across operating systems
+and it currently supports Unix, VMS, DOS, OS/2 and Windows. When
+porting to a new OS there are generally three main issues
+that have to be solved:
+
+=over 4
+
+=item *
+
+Can the OS unlink an open file? If it can not then the
+C<_can_unlink_opened_file> method should be modified.
+
+=item *
+
+Are the return values from C<stat> reliable? By default all the
+return values from C<stat> are compared when unlinking a temporary
+file using the filename and the handle. Operating systems other than
+unix do not always have valid entries in all fields. If C<unlink0> fails
+then the C<stat> comparison should be modified accordingly.
+
+=item *
+
+Security. Systems that can not support a test for the sticky bit
+on a directory can not use the MEDIUM and HIGH security tests.
+The C<_can_do_level> method should be modified accordingly.
+
+=back
+
+=end __INTERNALS
+
=head1 SYNOPSIS
use File::Temp qw/ tempfile tempdir /;
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.
+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(),
use File::Spec 0.8;
use File::Path qw/ rmtree /;
use Fcntl 1.03;
-use Errno qw( EEXIST ENOENT ENOTDIR EINVAL );
+use Errno;
require VMS::Stdio if $^O eq 'VMS';
# Need the Symbol package if we are running older perl
# Version number
-$VERSION = '0.10';
+$VERSION = '0.12';
# This is a list of characters that can be used in random filenames
for my $oflag (qw/ FOLLOW BINARY LARGEFILE EXLOCK NOINHERIT /) {
my ($bit, $func) = (0, "Fcntl::O_" . $oflag);
no strict 'refs';
- $OPENFLAGS |= $bit if eval { $bit = &$func(); 1 };
+ $OPENFLAGS |= $bit if eval {
+ # Make sure that redefined die handlers do not cause problems
+ # eg CGI::Carp
+ local $SIG{__DIE__} = sub {};
+ local $SIG{__WARN__} = sub {};
+ $bit = &$func();
+ 1;
+ };
}
# On some systems the O_TEMPORARY flag can be used to tell the OS
for my $oflag (qw/ TEMPORARY /) {
my ($bit, $func) = (0, "Fcntl::O_" . $oflag);
no strict 'refs';
- $OPENTEMPFLAGS |= $bit if eval { $bit = &$func(); 1 };
+ $OPENTEMPFLAGS |= $bit if eval {
+ # Make sure that redefined die handlers do not cause problems
+ # eg CGI::Carp
+ local $SIG{__DIE__} = sub {};
+ local $SIG{__WARN__} = sub {};
+ $bit = &$func();
+ 1;
+ };
}
-
# INTERNAL ROUTINES - not to be used outside of package
# Generic routine for getting a temporary filename
# use of the O_TEMPORARY flag to sysopen.
# Usually irrelevant on unix
+# 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.
# ($fh, $name) = _gettemp($template, "open" => 1);
# for the current version, failures are associated with
-# a carp to give the reason whilst debugging
-
+# 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,
+ "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"}) {
- carp "File::Temp::_gettemp: doopen and domkdir can not both be true\n";
+ ${$options{ErrStr}} = "doopen and domkdir can not both be true\n";
return ();
}
# 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";
+ ${$options{ErrStr}} = "The template must contain at least ".
+ MINX . " 'X' characters\n";
return ();
}
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
# 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";
+ unless (-d $parent) {
+ ${$options{ErrStr}} = "Parent directory ($parent) is not a directory";
+ return ();
+ }
+ unless (-w _) {
+ ${$options{ErrStr}} = "Parent directory ($parent) is not writable\n";
return ();
}
+
# Check the stickiness of the directory and chown giveaway if required
# If the directory is world writable the sticky bit
# must be set
if (File::Temp->safe_level == MEDIUM) {
- unless (_is_safe($parent)) {
- carp "File::Temp::_gettemp: Parent directory ($parent) is not safe (sticky bit not set when world writable?)";
+ my $safeerr;
+ unless (_is_safe($parent,\$safeerr)) {
+ ${$options{ErrStr}} = "Parent directory ($parent) is not safe ($safeerr)";
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?)";
+ my $safeerr;
+ unless (_is_verysafe($parent, \$safeerr)) {
+ ${$options{ErrStr}} = "Parent directory ($parent) is not safe ($safeerr)";
return ();
}
}
# 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;
+ local $^F = 2;
# Store callers umask
my $umask = umask();
# Attempt to open the file
my $open_success = undef;
- if ( $^O eq 'VMS' ) { # make it auto delete on close
+ if ( $^O eq 'VMS' and $options{"unlink_on_close"} ) {
+ # make it auto delete on close by setting FAB$V_DLT bit
$fh = VMS::Stdio::vmssysopen($path, $OPENFLAGS, 0600, 'fop=dlt');
$open_success = $fh;
} else {
# Error opening file - abort with error
# if the reason was anything but EEXIST
- unless ($! == EEXIST) {
- carp "File::Temp: Could not create temp file $path: $!";
+ unless ($!{EEXIST}) {
+ ${$options{ErrStr}} = "Could not create temp file $path: $!";
return ();
}
# Abort with error if the reason for failure was anything
# except EEXIST
- unless ($! == EEXIST) {
- carp "File::Temp: Could not create directory $path: $!";
+ unless ($!{EEXIST}) {
+ ${$options{ErrStr}} = "Could not create directory $path: $!";
return ();
}
# Check for out of control looping
if ($counter > $MAX_GUESS) {
- carp "Tried to get a new temp name different to the previous value $MAX_GUESS times.\nSomething wrong with template?? ($template)";
+ ${$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
- carp "Have exceeded the maximum number of attempts (".MAX_TRIES .
- ") to open temp file/dir";
+ ${ $options{ErrStr} } = "Have exceeded the maximum number of attempts ("
+ . MAX_TRIES . ") to open temp file/dir";
return ();
# 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
sub _is_safe {
my $path = shift;
+ my $err_ref = shift;
# Stat path
my @info = stat($path);
- return 0 unless scalar(@info);
+ unless (scalar(@info)) {
+ $$err_ref = "stat(path) returned no values";
+ return 0;
+ };
return 1 if $^O eq 'VMS'; # owner delete control at file level
# Check to see whether owner is neither superuser (or a system uid) nor me
# Use the real uid from the $< variable
# UID is in [4]
- if ( $info[4] > File::Temp->top_system_uid() && $info[4] != $<) {
- carp "Directory owned neither by root nor the current user";
+ if ($info[4] > File::Temp->top_system_uid() && $info[4] != $<) {
+
+ Carp::cluck(sprintf "uid=$info[4] topuid=%s \$<=$< path='$path'",
+ File::Temp->top_system_uid());
+
+ $$err_ref = "Directory owned neither by root nor the current user"
+ if ref($err_ref);
return 0;
}
# mode is in info[2]
if (($info[2] & &Fcntl::S_IWGRP) || # Is group writable?
($info[2] & &Fcntl::S_IWOTH) ) { # Is world writable?
- return 0 unless -d _; # Must be a directory
- return 0 unless -k _; # Must be sticky
+ # Must be a directory
+ unless (-d _) {
+ $$err_ref = "Path ($path) is not a directory"
+ if ref($err_ref);
+ return 0;
+ }
+ # Must have sticky bit set
+ unless (-k _) {
+ $$err_ref = "Sticky bit not set on $path when dir is group|world writable"
+ if ref($err_ref);
+ return 0;
+ }
}
return 1;
# 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
my $chown_restricted;
if (defined $chown_restricted) {
# Return if the current directory is safe
- return _is_safe($path) if POSIX::sysconf( $chown_restricted );
+ return _is_safe($path,$err_ref) if POSIX::sysconf( $chown_restricted );
}
print "TESTING DIR $dir\n" if $DEBUG;
# Check the directory
- return 0 unless _is_safe($dir);
+ return 0 unless _is_safe($dir,$err_ref);
}
sub _can_unlink_opened_file {
- if ($^O eq 'MSWin32' || $^O eq 'os2' || $^O eq 'VMS') {
+ if ($^O eq 'MSWin32' || $^O eq 'os2' || $^O eq 'VMS' || $^O eq 'dos') {
return 0;
} else {
return 1;
return 1 if $level == STANDARD;
# Currently, the systems that can do HIGH or MEDIUM are identical
- if ( $^O eq 'MSWin32' || $^O eq 'os2') {
+ if ( $^O eq 'MSWin32' || $^O eq 'os2' || $^O eq 'cygwin' || $^O eq 'dos') {
return 0;
} else {
return 1;
# probably a better way to do this
close($file->[0]); # file handle is [0]
- # On VMS, the file will be automatically deleted on close,
- # so we are through with the file already.
- next if $^O eq 'VMS';
-
if (-f $file->[1]) { # file name is [1]
unlink $file->[1] or warn "Error removing ".$file->[1];
}
}
}
-
}
# This is the sub called to register a file for deferred unlinking
push (@dirs_to_unlink, $fname);
} else {
- carp "Request to remove directory $fname could not be completed since it does not exist!\n";
+ carp "Request to remove directory $fname could not be completed since it does not exist!\n" if $^W;
}
} else {
push(@files_to_unlink, [$fh, $fname]);
} else {
- carp "Request to remove file $fname could not be completed since it is not there!\n";
+ carp "Request to remove file $fname could not be completed since it is not there!\n" if $^W;
}
}
Return the filename and filehandle as before except that the file is
automatically removed when the program exits. Default is for the file
to be removed if a file handle is requested and to be kept if the
-filename is requested.
+filename is requested. In a scalar context (where no filename is
+returned) the file is always deleted either on exit or when it is closed.
If the template is not specified, a template is always
automatically generated. This temporary file is placed in tmpdir()
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 (for example, Windows NT) the file is marked for
-deletion when the program ends (equivalent to setting UNLINK to 1).
+an open file or can not mark a file as temporary when it is opened
+(for example, Windows NT uses the C<O_TEMPORARY> flag))
+the file is marked for deletion when the program ends (equivalent
+to setting UNLINK to 1). The C<UNLINK> flag is ignored if present.
(undef, $filename) = tempfile($template, OPEN => 0);
# Default options
my %options = (
"DIR" => undef, # Directory prefix
- "SUFFIX" => '', # Template suffix
- "UNLINK" => 0, # Unlink file on exit
- "OPEN" => 1, # Do not open file
+ "SUFFIX" => '', # Template suffix
+ "UNLINK" => 0, # Do not unlink file on exit
+ "OPEN" => 1, # Open file
);
# Check to see whether we have an odd or even number of arguments
}
+ 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
# 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.
+ # 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);
- croak "Error in tempfile() using $template"
+ my ($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,
) );
# Set up an exit handler that can do whatever is right for the
- # system. Do not check return status since this is all done with
- # END blocks
+ # 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 $options{"UNLINK"};
# Return
# Prepend the supplied directory or temp dir
if ($options{"DIR"}) {
- $template = File::Spec->catfile($options{"DIR"}, $template);
+ $template = File::Spec->catdir($options{"DIR"}, $template);
} elsif ($options{TMPDIR}) {
$template =~ m/([\.\]:>]+)$/;
$suffixlen = length($1);
}
- croak "Error in tempdir() using $template"
+
+ 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
my $template = shift;
- my ($fh, $path);
- croak "Error in mkstemp using $template"
+ my ($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()) {
$template .= $suffix;
- my ($fh, $path);
- croak "Error in mkstemps using $template"
+ my ($fh, $path, $errstr);
+ croak "Error in mkstemps using $template: $errstr"
unless (($fh, $path) = _gettemp($template,
- "open" => 1,
+ "open" => 1,
"mkdir"=> 0 ,
"suffixlen" => length($suffix),
+ "ErrStr" => \$errstr,
) );
if (wantarray()) {
$template =~ m/([\.\]:>]+)$/;
$suffixlen = length($1);
}
- my ($junk, $tmpdir);
- croak "Error creating temp directory from template $template\n"
+ my ($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;
my $template = shift;
- my ($tmpname, $junk);
- croak "Error getting name to temp file from template $template\n"
+ my ($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 $tmpname;
The file is removed when the filehandle is closed or when the program
exits. No access to the filename is provided.
+If the temporary file can not be created undef is returned.
+Currently this command will probably not work when the temporary
+directory is on an NFS file system.
+
=cut
sub tmpfile {
my ($fh, $file) = tmpnam();
# Make sure file is removed when filehandle is closed
- unlink0($fh, $file) or croak "Unable to unlink temporary file: $!";
+ # This will fail on NFS
+ unlink0($fh, $file)
+ or return undef;
return $fh;
my @fh = stat $fh;
if ($fh[3] > 1 && $^W) {
- carp "unlink0: fstat found too many links; SB=@fh";
+ carp "unlink0: fstat found too many links; SB=@fh" if $^W;
}
# Stat the path
@okstat = (0, 2..$#fh);
} elsif ($^O eq 'VMS') { # device and file ID are sufficient
@okstat = (0, 1);
+ } elsif ($^O eq 'dos') {
+ @okstat = (0,2..7,11..$#fh);
}
# Now compare each entry explicitly by number
print "Link count = $fh[3] \n" if $DEBUG;
# Make sure that the link count is zero
- return ( $fh[3] == 0 ? 1 : 0);
+ # - 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);
if (@_) {
my $level = shift;
if (($level != STANDARD) && ($level != MEDIUM) && ($level != HIGH)) {
- carp "safe_level: Specified level ($level) not STANDARD, MEDIUM or HIGH - ignoring\n";
+ carp "safe_level: Specified level ($level) not STANDARD, MEDIUM or HIGH - ignoring\n" if $^W;
} else {
# Dont allow this on perl 5.005 or earlier
if ($] < 5.006 && $level != STANDARD) {
fcntl($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.
+
=head1 HISTORY
Originally began life in May 1999 as an XS interface to the system
-mkstemp() function. In March 2000, the mkstemp() code was
+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.
L<POSIX/tmpnam>, L<POSIX/tmpfile>, L<File::Spec>, L<File::Path>
-See L<File::MkTemp> for a different implementation of temporary
-file handling.
+See L<IO::File> and L<File::MkTemp> for different implementations 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
+Copyright (C) 1999-2001 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.
projects / p5sagit/p5-mst-13.2.git / blobdiff