| File::Path(3perl) | Perl Programmers Reference Guide | File::Path(3perl) |
File::Path - Create or remove directory trees
2.15 - released June 07 2017.
use File::Path qw(make_path remove_tree);
@created = make_path('foo/bar/baz', '/zug/zwang');
@created = make_path('foo/bar/baz', '/zug/zwang', {
verbose => 1,
mode => 0711,
});
make_path('foo/bar/baz', '/zug/zwang', {
chmod => 0777,
});
$removed_count = remove_tree('foo/bar/baz', '/zug/zwang', {
verbose => 1,
error => \my $err_list,
safe => 1,
});
# legacy (interface promoted before v2.00)
@created = mkpath('/foo/bar/baz');
@created = mkpath('/foo/bar/baz', 1, 0711);
@created = mkpath(['/foo/bar/baz', 'blurfl/quux'], 1, 0711);
$removed_count = rmtree('foo/bar/baz', 1, 1);
$removed_count = rmtree(['foo/bar/baz', 'blurfl/quux'], 1, 1);
# legacy (interface promoted before v2.06)
@created = mkpath('foo/bar/baz', '/zug/zwang', { verbose => 1, mode => 0711 });
$removed_count = rmtree('foo/bar/baz', '/zug/zwang', { verbose => 1, mode => 0711 });
This module provides a convenient way to create directories of arbitrary depth and to delete an entire directory subtree from the filesystem.
The following functions are provided:
The function accepts a list of directories to be created. Its behaviour may be tuned by an optional hashref appearing as the last parameter on the call.
The function returns the list of directories actually created during the call; in scalar context the number of directories created.
The following keys are recognised in the option hash:
"mask" is recognised as an alias for this parameter.
If this parameter is not used, certain error conditions may raise a fatal error that will cause the program to halt, unless trapped in an "eval" block.
Ownership of directories that already exist will not be changed.
"user" and "uid" are aliases of "owner".
Group ownership of directories that already exist will not be changed.
make_path '/var/tmp/webcache', {owner=>'nobody', group=>'nogroup'};
The function accepts a list of directories to be removed. (In point of fact, it will also accept filesystem entries which are not directories, such as regular files and symlinks. But, as its name suggests, its intent is to remove trees rather than individual files.)
"remove_tree()"'s behaviour may be tuned by an optional hashref appearing as the last parameter on the call. If an empty string is passed to "remove_tree", an error will occur.
NOTE: For security reasons, we strongly advise use of the hashref-as-final-argument syntax -- specifically, with a setting of the "safe" element to a true value.
remove_tree( $dir1, $dir2, ....,
{
safe => 1,
... # other key-value pairs
},
);
The function returns the number of files successfully deleted.
The following keys are recognised in the option hash:
remove_tree( '/tmp', {keep_root => 1} );
remove_tree( '/tmp', {result => \my $list} );
print "unlinked $_\n" for @$list;
This is a useful alternative to the "verbose" key.
Removing things is a much more dangerous proposition than creating things. As such, there are certain conditions that "remove_tree" may encounter that are so dangerous that the only sane action left is to kill the program.
Use "error" to trap all that is reasonable (problems with permissions and the like), and let it die if things get out of hand. This is the safest course of action.
NOTE: For security reasons, we strongly advise use of the hashref-as-final-argument syntax, specifically with a setting of the "safe" element to a true value.
rmtree( $dir1, $dir2, ....,
{
safe => 1,
... # other key-value pairs
},
);
If "make_path" or "remove_tree" encounters an error, a diagnostic message will be printed to "STDERR" via "carp" (for non-fatal errors) or via "croak" (for fatal errors).
If this behaviour is not desirable, the "error" attribute may be used to hold a reference to a variable, which will be used to store the diagnostics. The variable is made a reference to an array of hash references. Each hash contain a single key/value pair where the key is the name of the file, and the value is the error message (including the contents of $! when appropriate). If a general error is encountered the diagnostic key will be empty.
An example usage looks like:
remove_tree( 'foo/bar', 'bar/rat', {error => \my $err} );
if ($err && @$err) {
for my $diag (@$err) {
my ($file, $message) = %$diag;
if ($file eq '') {
print "general error: $message\n";
}
else {
print "problem unlinking $file: $message\n";
}
}
}
else {
print "No error encountered\n";
}
Note that if no errors are encountered, $err will reference an empty array. This means that $err will always end up TRUE; so you need to test @$err to determine if errors occurred.
"File::Path" blindly exports "mkpath" and "rmtree" into the current namespace. These days, this is considered bad style, but to change it now would break too much code. Nonetheless, you are invited to specify what it is you are expecting to use:
use File::Path 'rmtree';
The routines "make_path" and "remove_tree" are not exported by default. You must specify which ones you want to use.
use File::Path 'remove_tree';
Note that a side-effect of the above is that "mkpath" and "rmtree" are no longer exported at all. This is due to the way the "Exporter" module works. If you are migrating a codebase to use the new interface, you will have to list everything explicitly. But that's just good practice anyway.
use File::Path qw(remove_tree rmtree);
API CHANGES
The API was changed in the 2.0 branch. For a time, "mkpath" and "rmtree" tried, unsuccessfully, to deal with the two different calling mechanisms. This approach was considered a failure.
The new semantics are now only available with "make_path" and "remove_tree". The old semantics are only available through "mkpath" and "rmtree". Users are strongly encouraged to upgrade to at least 2.08 in order to avoid surprises.
SECURITY CONSIDERATIONS
There were race conditions in the 1.x implementations of File::Path's "rmtree" function (although sometimes patched depending on the OS distribution or platform). The 2.0 version contains code to avoid the problem mentioned in CVE-2002-0435.
See the following pages for more information:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=286905
http://www.nntp.perl.org/group/perl.perl5.porters/2005/01/msg97623.html
http://www.debian.org/security/2005/dsa-696
Additionally, unless the "safe" parameter is set (or the third parameter in the traditional interface is TRUE), should a "remove_tree" be interrupted, files that were originally in read-only mode may now have their permissions set to a read-write (or "delete OK") mode.
The following CVE reports were previously filed against File-Path and are believed to have been addressed:
In February 2017 the cPanel Security Team reported an additional vulnerability in File-Path. The "chmod()" logic to make directories traversable can be abused to set the mode on an attacker-chosen file to an attacker-chosen value. This is due to the time-of-check-to-time-of-use (TOCTTOU) race condition (<https://en.wikipedia.org/wiki/Time_of_check_to_time_of_use>) between the "stat()" that decides the inode is a directory and the "chmod()" that tries to make it user-rwx. CPAN versions 2.13 and later incorporate a patch provided by John Lightsey to address this problem. This vulnerability has been reported as CVE-2017-6512.
FATAL errors will cause the program to halt ("croak"), since the problem is so severe that it would be dangerous to continue. (This can always be trapped with "eval", but it's not a good idea. Under the circumstances, dying is the best thing to do).
SEVERE errors may be trapped using the modern interface. If the they are not trapped, or if the old interface is used, such an error will cause the program will halt.
All other errors may be trapped using the modern interface, otherwise they will be "carp"ed about. Program execution will not be halted.
The solution is to "chdir" out of the child directory to a place outside the directory tree to be removed.
Allows files and directories to be moved to the Trashcan/Recycle Bin (where they may later be restored if necessary) if the operating system supports such functionality. This feature may one day be made available directly in "File::Path".
When removing directory trees, if you want to examine each file to decide whether to delete it (and possibly leaving large swathes alone), File::Find::Rule offers a convenient and flexible approach to examining directory trees.
The following describes File::Path limitations and how to report bugs.
File::Path "rmtree" and "remove_tree" will not work with multithreaded applications due to its use of "chdir". At this time, no warning or error is generated in this situation. You will certainly encounter unexpected results.
The implementation that surfaces this limitation will not be changed. See the File::Path::Tiny module for functionality similar to File::Path but which does not "chdir".
File::Path is not responsible for triggering the automounts, mirror mounts, and the contents of network mounted filesystems. If your NFS implementation requires an action to be performed on the filesystem in order for File::Path to perform operations, it is strongly suggested you assure filesystem availability by reading the root of the mounted filesystem.
Please report all bugs on the RT queue, either via the web interface:
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=File-Path>
or by email:
bug-File-Path@rt.cpan.org
In either case, please attach patches to the bug report rather than including them inline in the web post or the body of the email.
You can also send pull requests to the Github repository:
<https://github.com/rpcme/File-Path>
Paul Szabo identified the race condition originally, and Brendan O'Dea wrote an implementation for Debian that addressed the problem. That code was used as a basis for the current code. Their efforts are greatly appreciated.
Gisle Aas made a number of improvements to the documentation for 2.07 and his advice and assistance is also greatly appreciated.
Prior authors and maintainers: Tim Bunce, Charles Bailey, and David Landgren <david@landgren.net>.
Current maintainers are Richard Elberger <riche@cpan.org> and James (Jim) Keenan <jkeenan@cpan.org>.
Contributors to File::Path, in alphabetical order by first name.
This module is copyright (C) Charles Bailey, Tim Bunce, David Landgren, James Keenan and Richard Elberger 1995-2017. All rights reserved.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
| 2020-07-21 | perl v5.28.1 |