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Section: User Contributed Perl Documentation (3)
Updated: 2009-10-04
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NAME

File::Path - Create or remove directory trees

VERSION

This document describes version 2.08 of File::Path, released2009-10-04.

SYNOPSIS

  use File::Path qw(make_path remove_tree);  make_path('foo/bar/baz', '/zug/zwang');  make_path('foo/bar/baz', '/zug/zwang', {      verbose => 1,      mode => 0711,  });  remove_tree('foo/bar/baz', '/zug/zwang');  remove_tree('foo/bar/baz', '/zug/zwang', {      verbose => 1,      error  => \my $err_list,  });  # legacy (interface promoted before v2.00)  mkpath('/foo/bar/baz');  mkpath('/foo/bar/baz', 1, 0711);  mkpath(['/foo/bar/baz', 'blurfl/quux'], 1, 0711);  rmtree('foo/bar/baz', 1, 1);  rmtree(['foo/bar/baz', 'blurfl/quux'], 1, 1);  # legacy (interface promoted before v2.06)  mkpath('foo/bar/baz', '/zug/zwang', { verbose => 1, mode => 0711 });  rmtree('foo/bar/baz', '/zug/zwang', { verbose => 1, mode => 0711 });

DESCRIPTION

This module provide a convenient way to create directories ofarbitrary depth and to delete an entire directory subtree from thefilesystem.

The following functions are provided:

make_path( $dir1, $dir2, .... )

make_path( $dir1, $dir2, ...., \%opts )

The "make_path" function creates the given directories if they don'texists before, much like the Unix command "mkdir -p".

The function accepts a list of directories to be created. Itsbehaviour may be tuned by an optional hashref appearing as the lastparameter on the call.

The function returns the list of directories actually created duringthe call; in scalar context the number of directories created.

The following keys are recognised in the option hash:

mode => $num

The numeric permissions mode to apply to each created directory(defaults to 0777), to be modified by the current "umask". If thedirectory already exists (and thus does not need to be created),the permissions will not be modified.

"mask" is recognised as an alias for this parameter.

verbose => $bool

If present, will cause "make_path" to print the name of each directoryas it is created. By default nothing is printed.

error => \$err

If present, it should be a reference to a scalar.This scalar will be made to reference an array, which willbe used to store any errors that are encountered. See the ``ERRORHANDLING'' section for more information.

If this parameter is not used, certain error conditions may raisea fatal error that will cause the program will halt, unless trappedin an "eval" block.

owner => $owner

user => $owner

uid => $owner

If present, will cause any created directory to be owned by $owner.If the value is numeric, it will be interpreted as a uid, otherwiseas username is assumed. An error will be issued if the username cannot bemapped to a uid, or the uid does not exist, or the process lacks theprivileges to change ownership.

Ownwership of directories that already exist will not be changed.

"user" and "uid" are aliases of "owner".

group => $group

If present, will cause any created directory to be owned by the group $group.If the value is numeric, it will be interpreted as a gid, otherwiseas group name is assumed. An error will be issued if the group name cannot bemapped to a gid, or the gid does not exist, or the process lacks theprivileges to change group ownership.

Group ownwership of directories that already exist will not be changed.

    make_path '/var/tmp/webcache', {owner=>'nobody', group=>'nogroup'};

mkpath( $dir )

mkpath( $dir, $verbose, $mode )

mkpath( [$dir1, $dir2,...], $verbose, $mode )

mkpath( $dir1, $dir2,..., \%opt )

The mkpath() function provide the legacy interface of make_path() witha different interpretation of the arguments passed. The behaviour andreturn value of the function is otherwise identical to make_path().

remove_tree( $dir1, $dir2, .... )

remove_tree( $dir1, $dir2, ...., \%opts )

The "remove_tree" function deletes the given directories and anyfiles and subdirectories they might contain, much like the Unixcommand "rm -r" or "del /s" on Windows.

The function accepts a list of directories to beremoved. Its behaviour may be tuned by an optional hashrefappearing as the last parameter on the call.

The functions returns the number of files successfully deleted.

The following keys are recognised in the option hash:

verbose => $bool

If present, will cause "remove_tree" to print the name of each file asit is unlinked. By default nothing is printed.

safe => $bool

When set to a true value, will cause "remove_tree" to skip the filesfor which the process lacks the required privileges needed to deletefiles, such as delete privileges on VMS. In other words, the codewill make no attempt to alter file permissions. Thus, if the processis interrupted, no filesystem object will be left in a morepermissive mode.

keep_root => $bool

When set to a true value, will cause all files and subdirectoriesto be removed, except the initially specified directories. This comesin handy when cleaning out an application's scratch directory.

  remove_tree( '/tmp', {keep_root => 1} );

result => \$res

If present, it should be a reference to a scalar.This scalar will be made to reference an array, which willbe used to store all files and directories unlinkedduring the call. If nothing is unlinked, the array will be empty.

  remove_tree( '/tmp', {result => \my $list} );  print "unlinked $_\n" for @$list;

This is a useful alternative to the "verbose" key.

error => \$err

Removing things is a much more dangerous proposition thancreating things. As such, there are certain conditions that"remove_tree" may encounter that are so dangerous that the onlysane action left is to kill the program.

Use "error" to trap all that is reasonable (problems withpermissions and the like), and let it die if things get outof hand. This is the safest course of action.

rmtree( $dir )

rmtree( $dir, $verbose, $safe )

rmtree( [$dir1, $dir2,...], $verbose, $safe )

rmtree( $dir1, $dir2,..., \%opt )

The rmtree() function provide the legacy interface of remove_tree()with a different interpretation of the arguments passed. The behaviourand return value of the function is otherwise identical toremove_tree().

ERROR HANDLING

NOTE:: The following error handling mechanism is consideredexperimental and is subject to change pending feedback fromusers.

If "make_path" or "remove_tree" encounter an error, a diagnosticmessage will be printed to "STDERR" via "carp" (for non-fatalerrors), or via "croak" (for fatal errors).

If this behaviour is not desirable, the "error" attribute may beused to hold a reference to a variable, which will be used to storethe diagnostics. The variable is made a reference to an array of hashreferences. Each hash contain a single key/value pair where the keyis the name of the file, and the value is the error message (includingthe contents of $! when appropriate). If a general error isencountered the diagnostic key will be empty.

An example usage looks like:

  remove_tree( 'foo/bar', 'bar/rat', {error => \my $err} );  if (@$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 anempty array. This means that $err will always end up TRUE; so youneed to test @$err to determine if errors occured.

NOTES

"File::Path" blindly exports "mkpath" and "rmtree" into thecurrent namespace. These days, this is considered bad style, butto change it now would break too much code. Nonetheless, you areinvited to specify what it is you are expecting to use:

  use File::Path 'rmtree';

The routines "make_path" and "remove_tree" are not exportedby 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 newinterface, you will have to list everything explicitly. But that'sjust 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 differentcalling 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 upgradeto at least 2.08 in order to avoid surprises.

SECURITY CONSIDERATIONS

There were race conditions 1.x implementations of File::Path's"rmtree" function (although sometimes patched depending on the OSdistribution or platform). The 2.0 version contains code to avoid theproblem 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 thethird parameter in the traditional interface is TRUE), should a"remove_tree" be interrupted, files that were originally in read-onlymode may now have their permissions set to a read-write (or ``deleteOK'') mode.

DIAGNOSTICS

FATAL errors will cause the program to halt ("croak"), since theproblem is so severe that it would be dangerous to continue. (Thiscan always be trapped with "eval", but it's not a good idea. Underthe circumstances, dying is the best thing to do).

SEVERE errors may be trapped using the modern interface. If thethey are not trapped, or the old interface is used, such an errorwill cause the program will halt.

All other errors may be trapped using the modern interface, otherwisethey will be "carp"ed about. Program execution will not be halted.

mkdir [path]: [errmsg] (SEVERE): "make_path" was unable to create the path. Probably some sort ofpermissions error at the point of departure, or insufficient resources(such as free inodes on Unix).
No root path(s) specified: "make_path" was not given any paths to create. This message is onlyemitted if the routine is called with the traditional interface.The modern interface will remain silent if given nothing to do.
No such file or directory: On Windows, if "make_path" gives you this warning, it may mean thatyou have exceeded your filesystem's maximum path length.
cannot fetch initial working directory: [errmsg]: "remove_tree" attempted to determine the initial directory by calling"Cwd::getcwd", but the call failed for some reason. No attemptwill be made to delete anything.
cannot stat initial working directory: [errmsg]: "remove_tree" attempted to stat the initial directory (after havingsuccessfully obtained its name via "getcwd"), however, the callfailed for some reason. No attempt will be made to delete anything.
cannot chdir to [dir]: [errmsg]: "remove_tree" attempted to set the working directory in order tobegin deleting the objects therein, but was unsuccessful. This isusually a permissions issue. The routine will continue to deleteother things, but this directory will be left intact.
directory [dir] changed before chdir, expected dev=[n] ino=[n], actual dev=[n] ino=[n], aborting. (FATAL): "remove_tree" recorded the device and inode of a directory, and thenmoved into it. It then performed a "stat" on the current directoryand detected that the device and inode were no longer the same. Asthis is at the heart of the race condition problem, the programwill die at this point.
cannot make directory [dir] read+writeable: [errmsg]: "remove_tree" attempted to change the permissions on the current directoryto ensure that subsequent unlinkings would not run into problems,but was unable to do so. The permissions remain as they were, andthe program will carry on, doing the best it can.
cannot read [dir]: [errmsg]: "remove_tree" tried to read the contents of the directory in orderto acquire the names of the directory entries to be unlinked, butwas unsuccessful. This is usually a permissions issue. Theprogram will continue, but the files in this directory will remainafter the call.
cannot reset chmod [dir]: [errmsg]: "remove_tree", after having deleted everything in a directory, attemptedto restore its permissions to the original state but failed. Thedirectory may wind up being left behind.
cannot remove [dir] when cwd is [dir]: The current working directory of the program is /some/path/to/hereand you are attempting to remove an ancestor, such as /some/path.The directory tree is left untouched.
The solution is to "chdir" out of the child directory to a placeoutside the directory tree to be removed.
cannot chdir to [parent-dir] from [child-dir]: [errmsg], aborting. (FATAL): "remove_tree", after having deleted everything and restored the permissionsof a directory, was unable to chdir back to the parent. The programhalts to avoid a race condition from occurring.
cannot stat prior working directory [dir]: [errmsg], aborting. (FATAL): "remove_tree" was unable to stat the parent directory after have returnedfrom the child. Since there is no way of knowing if we returned towhere we think we should be (by comparing device and inode) the onlyway out is to "croak".
previous directory [parent-dir] changed before entering [child-dir], expected dev=[n] ino=[n], actual dev=[n] ino=[n], aborting. (FATAL): When "remove_tree" returned from deleting files in a child directory, acheck revealed that the parent directory it returned to wasn't the oneit started out from. This is considered a sign of malicious activity.
cannot make directory [dir] writeable: [errmsg]: Just before removing a directory (after having successfully removedeverything it contained), "remove_tree" attempted to set the permissionson the directory to ensure it could be removed and failed. Programexecution continues, but the directory may possibly not be deleted.
cannot remove directory [dir]: [errmsg]: "remove_tree" attempted to remove a directory, but failed. This may becausesome objects that were unable to be removed remain in the directory, ora permissions issue. The directory will be left behind.
cannot restore permissions of [dir] to [0nnn]: [errmsg]: After having failed to remove a directory, "remove_tree" was unable torestore its permissions from a permissive state back to a possiblymore restrictive setting. (Permissions given in octal).
cannot make file [file] writeable: [errmsg]: "remove_tree" attempted to force the permissions of a file to ensure itcould be deleted, but failed to do so. It will, however, still attemptto unlink the file.
cannot unlink file [file]: [errmsg]: "remove_tree" failed to remove a file. Probably a permissions issue.
cannot restore permissions of [file] to [0nnn]: [errmsg]: After having failed to remove a file, "remove_tree" was also unableto restore the permissions on the file to a possibly less permissivesetting. (Permissions given in octal).
unable to map [owner] to a uid, ownership not changed);: "make_path" was instructed to give the ownership of createddirectories to the symbolic name [owner], but "getpwnam" didnot return the corresponding numeric uid. The directory willbe created, but ownership will not be changed.
unable to map [group] to a gid, group ownership not changed: "make_path" was instructed to give the group ownership of createddirectories to the symbolic name [group], but "getgrnam" didnot return the corresponding numeric gid. The directory willbe created, but group ownership will not be changed.

BUGS

Please report all bugs on the RT queue:

<http://rt.cpan.org/NoAuth/Bugs.html?Dist=File-Path>

ACKNOWLEDGEMENTS

Paul Szabo identified the race condition originally, and BrendanO'Dea wrote an implementation for Debian that addressed the problem.That code was used as a basis for the current code. Their effortsare greatly appreciated.

Gisle Aas made a number of improvements to the documentation for2.07 and his advice and assistance is also greatly appreciated.