tarfile — Read and write tar archive files — Python 3.14.4 documentation

tarfile — Read and write tar archive files — Python 3.14.4 documentation
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Python
3.14.4 Documentation
The Python Standard Library
Data Compression and Archiving
tarfile
— Read and write tar archive files
Theme
tarfile
— Read and write tar archive files
Source code:
Lib/tarfile.py
The
tarfile
module makes it possible to read and write tar
archives, including those using gzip, bz2 and lzma compression.
Use the
zipfile
module to read or write
.zip
files, or the
higher-level functions in
shutil
Some facts and figures:
reads and writes
gzip
bz2
compression.zstd
, and
lzma
compressed archives if the respective modules are available.
If any of these
optional modules
are missing from
your copy of CPython, look for documentation from your distributor (that is,
whoever provided Python to you).
If you are the distributor, see
Requirements for optional modules
read/write support for the POSIX.1-1988 (ustar) format.
read/write support for the GNU tar format including
longname
and
longlink
extensions, read-only support for all variants of the
sparse
extension
including restoration of sparse files.
read/write support for the POSIX.1-2001 (pax) format.
handles directories, regular files, hardlinks, symbolic links, fifos,
character devices and block devices and is able to acquire and restore file
information like timestamp, access permissions and owner.
Changed in version 3.3:
Added support for
lzma
compression.
Changed in version 3.12:
Archives are extracted using a
filter
which makes it possible to either limit surprising/dangerous features,
or to acknowledge that they are expected and the archive is fully trusted.
Changed in version 3.14:
Set the default extraction filter to
data
which disallows some dangerous features such as links to absolute paths
or paths outside of the destination. Previously, the filter strategy
was equivalent to
fully_trusted
Changed in version 3.14:
Added support for Zstandard compression using
compression.zstd
tarfile.
open
name
None
mode
'r'
fileobj
None
bufsize
10240
**
kwargs
Return a
TarFile
object for the pathname
name
. For detailed
information on
TarFile
objects and the keyword arguments that are
allowed, see
TarFile Objects
mode
has to be a string of the form
'filemode[:compression]'
, it defaults
to
'r'
. Here is a full list of mode combinations:
mode
action
'r'
or
'r:*'
Open for reading with transparent
compression (recommended).
'r:'
Open for reading exclusively without
compression.
'r:gz'
Open for reading with gzip compression.
'r:bz2'
Open for reading with bzip2 compression.
'r:xz'
Open for reading with lzma compression.
'r:zst'
Open for reading with Zstandard compression.
'x'
or
'x:'
Create a tarfile exclusively without
compression.
Raise a
FileExistsError
exception
if it already exists.
'x:gz'
Create a tarfile with gzip compression.
Raise a
FileExistsError
exception
if it already exists.
'x:bz2'
Create a tarfile with bzip2 compression.
Raise a
FileExistsError
exception
if it already exists.
'x:xz'
Create a tarfile with lzma compression.
Raise a
FileExistsError
exception
if it already exists.
'x:zst'
Create a tarfile with Zstandard compression.
Raise a
FileExistsError
exception
if it already exists.
'a'
or
'a:'
Open for appending with no compression. The
file is created if it does not exist.
'w'
or
'w:'
Open for uncompressed writing.
'w:gz'
Open for gzip compressed writing.
'w:bz2'
Open for bzip2 compressed writing.
'w:xz'
Open for lzma compressed writing.
'w:zst'
Open for Zstandard compressed writing.
Note that
'a:gz'
'a:bz2'
or
'a:xz'
is not possible. If
mode
is not suitable to open a certain (compressed) file for reading,
ReadError
is raised. Use
mode
'r'
to avoid this. If a
compression method is not supported,
CompressionError
is raised.
If
fileobj
is specified, it is used as an alternative to a
file object
opened in binary mode for
name
. It is supposed to be at position 0.
For modes
'w:gz'
'x:gz'
'w|gz'
'w:bz2'
'x:bz2'
'w|bz2'
tarfile.open()
accepts the keyword argument
compresslevel
(default
) to specify the compression level of the file.
For modes
'w:xz'
'x:xz'
and
'w|xz'
tarfile.open()
accepts the
keyword argument
preset
to specify the compression level of the file.
For modes
'w:zst'
'x:zst'
and
'w|zst'
tarfile.open()
accepts the keyword argument
level
to specify the compression level of
the file. The keyword argument
options
may also be passed, providing
advanced Zstandard compression parameters described by
CompressionParameter
. The keyword argument
zstd_dict
can be passed to provide a
ZstdDict
a Zstandard dictionary used to improve compression of smaller amounts of
data.
For special purposes, there is a second format for
mode
'filemode|[compression]'
tarfile.open()
will return a
TarFile
object that processes its data as a stream of blocks. No random seeking will
be done on the file. If given,
fileobj
may be any object that has a
read()
or
write()
method
(depending on the
mode
) that works with bytes.
bufsize
specifies the blocksize and defaults to
20
512
bytes.
Use this variant in combination with e.g.
sys.stdin.buffer
, a socket
file object
or a tape device.
However, such a
TarFile
object is limited in that it does
not allow random access, see
Examples
. The currently
possible modes:
Mode
Action
'r|*'
Open a
stream
of tar blocks for reading
with transparent compression.
'r|'
Open a
stream
of uncompressed tar blocks
for reading.
'r|gz'
Open a gzip compressed
stream
for
reading.
'r|bz2'
Open a bzip2 compressed
stream
for
reading.
'r|xz'
Open an lzma compressed
stream
for
reading.
'r|zst'
Open a Zstandard compressed
stream
for
reading.
'w|'
Open an uncompressed
stream
for writing.
'w|gz'
Open a gzip compressed
stream
for
writing.
'w|bz2'
Open a bzip2 compressed
stream
for
writing.
'w|xz'
Open an lzma compressed
stream
for
writing.
'w|zst'
Open a Zstandard compressed
stream
for
writing.
Changed in version 3.5:
The
'x'
(exclusive creation) mode was added.
Changed in version 3.6:
The
name
parameter accepts a
path-like object
Changed in version 3.12:
The
compresslevel
keyword argument also works for streams.
Changed in version 3.14:
The
preset
keyword argument also works for streams.
class
tarfile.
TarFile
Class for reading and writing tar archives. Do not use this class directly:
use
tarfile.open()
instead. See
TarFile Objects
tarfile.
is_tarfile
name
Return
True
if
name
is a tar archive file, that the
tarfile
module can read.
name
may be a
str
, file, or file-like object.
Changed in version 3.9:
Support for file and file-like objects.
The
tarfile
module defines the following exceptions:
exception
tarfile.
TarError
Base class for all
tarfile
exceptions.
exception
tarfile.
ReadError
Is raised when a tar archive is opened, that either cannot be handled by the
tarfile
module or is somehow invalid.
exception
tarfile.
CompressionError
Is raised when a compression method is not supported or when the data cannot be
decoded properly.
exception
tarfile.
StreamError
Is raised for the limitations that are typical for stream-like
TarFile
objects.
exception
tarfile.
ExtractError
Is raised for
non-fatal
errors when using
TarFile.extract()
, but only if
TarFile.errorlevel
==
exception
tarfile.
HeaderError
Is raised by
TarInfo.frombuf()
if the buffer it gets is invalid.
exception
tarfile.
FilterError
Base class for members
refused
by
filters.
tarinfo
Information about the member that the filter refused to extract,
as
TarInfo
exception
tarfile.
AbsolutePathError
Raised to refuse extracting a member with an absolute path.
exception
tarfile.
OutsideDestinationError
Raised to refuse extracting a member outside the destination directory.
exception
tarfile.
SpecialFileError
Raised to refuse extracting a special file (e.g. a device or pipe).
exception
tarfile.
AbsoluteLinkError
Raised to refuse extracting a symbolic link with an absolute path.
exception
tarfile.
LinkOutsideDestinationError
Raised to refuse extracting a symbolic link pointing outside the destination
directory.
exception
tarfile.
LinkFallbackError
Raised to refuse emulating a link (hard or symbolic) by extracting another
archive member, when that member would be rejected by the filter location.
The exception that was raised to reject the replacement member is available
as
BaseException.__context__
Added in version 3.14.
The following constants are available at the module level:
tarfile.
ENCODING
The default character encoding:
'utf-8'
on Windows, the value returned by
sys.getfilesystemencoding()
otherwise.
tarfile.
REGTYPE
tarfile.
AREGTYPE
A regular file
type
tarfile.
LNKTYPE
A link (inside tarfile)
type
tarfile.
SYMTYPE
A symbolic link
type
tarfile.
CHRTYPE
A character special device
type
tarfile.
BLKTYPE
A block special device
type
tarfile.
DIRTYPE
A directory
type
tarfile.
FIFOTYPE
A FIFO special device
type
tarfile.
CONTTYPE
A contiguous file
type
tarfile.
GNUTYPE_LONGNAME
A GNU tar longname
type
tarfile.
GNUTYPE_LONGLINK
A GNU tar longlink
type
tarfile.
GNUTYPE_SPARSE
A GNU tar sparse file
type
Each of the following constants defines a tar archive format that the
tarfile
module is able to create. See section
Supported tar formats
for
details.
tarfile.
USTAR_FORMAT
POSIX.1-1988 (ustar) format.
tarfile.
GNU_FORMAT
GNU tar format.
tarfile.
PAX_FORMAT
POSIX.1-2001 (pax) format.
tarfile.
DEFAULT_FORMAT
The default format for creating archives. This is currently
PAX_FORMAT
Changed in version 3.8:
The default format for new archives was changed to
PAX_FORMAT
from
GNU_FORMAT
See also
Module
zipfile
Documentation of the
zipfile
standard module.
Archiving operations
Documentation of the higher-level archiving facilities provided by the
standard
shutil
module.
GNU tar manual, Basic Tar Format
Documentation for tar archive files, including GNU tar extensions.
TarFile Objects
The
TarFile
object provides an interface to a tar archive. A tar
archive is a sequence of blocks. An archive member (a stored file) is made up of
a header block followed by data blocks. It is possible to store a file in a tar
archive several times. Each archive member is represented by a
TarInfo
object, see
TarInfo Objects
for details.
TarFile
object can be used as a context manager in a
with
statement. It will automatically be closed when the block is completed. Please
note that in the event of an exception an archive opened for writing will not
be finalized; only the internally used file object will be closed. See the
Examples
section for a use case.
Added in version 3.2:
Added support for the context management protocol.
class
tarfile.
TarFile
name
None
mode
'r'
fileobj
None
format
DEFAULT_FORMAT
tarinfo
TarInfo
dereference
False
ignore_zeros
False
encoding
ENCODING
errors
'surrogateescape'
pax_headers
None
debug
errorlevel
stream
False
All following arguments are optional and can be accessed as instance attributes
as well.
name
is the pathname of the archive.
name
may be a
path-like object
It can be omitted if
fileobj
is given.
In this case, the file object’s
name
attribute is used if it exists.
mode
is either
'r'
to read from an existing archive,
'a'
to append
data to an existing file,
'w'
to create a new file overwriting an existing
one, or
'x'
to create a new file only if it does not already exist.
If
fileobj
is given, it is used for reading or writing data. If it can be
determined,
mode
is overridden by
fileobj
’s mode.
fileobj
will be used
from position 0.
Note
fileobj
is not closed, when
TarFile
is closed.
format
controls the archive format for writing. It must be one of the constants
USTAR_FORMAT
GNU_FORMAT
or
PAX_FORMAT
that are
defined at module level. When reading, format will be automatically detected, even
if different formats are present in a single archive.
The
tarinfo
argument can be used to replace the default
TarInfo
class
with a different one.
If
dereference
is
False
, add symbolic and hard links to the archive. If it
is
True
, add the content of the target files to the archive. This has no
effect on systems that do not support symbolic links.
If
ignore_zeros
is
False
, treat an empty block as the end of the archive.
If it is
True
, skip empty (and invalid) blocks and try to get as many members
as possible. This is only useful for reading concatenated or damaged archives.
debug
can be set from
(no debug messages) up to
(all debug
messages). The messages are written to
sys.stderr
errorlevel
controls how extraction errors are handled,
see
the
corresponding
attribute
The
encoding
and
errors
arguments define the character encoding to be
used for reading or writing the archive and how conversion errors are going
to be handled. The default settings will work for most users.
See section
Unicode issues
for in-depth information.
The
pax_headers
argument is an optional dictionary of strings which
will be added as a pax global header if
format
is
PAX_FORMAT
If
stream
is set to
True
then while reading the archive info about files
in the archive are not cached, saving memory.
Changed in version 3.2:
Use
'surrogateescape'
as the default for the
errors
argument.
Changed in version 3.5:
The
'x'
(exclusive creation) mode was added.
Changed in version 3.6:
The
name
parameter accepts a
path-like object
Changed in version 3.13:
Add the
stream
parameter.
classmethod
TarFile.
open
...
Alternative constructor. The
tarfile.open()
function is actually a
shortcut to this classmethod.
TarFile.
getmember
name
Return a
TarInfo
object for member
name
. If
name
can not be found
in the archive,
KeyError
is raised.
Note
If a member occurs more than once in the archive, its last occurrence is assumed
to be the most up-to-date version.
TarFile.
getmembers
Return the members of the archive as a list of
TarInfo
objects. The
list has the same order as the members in the archive.
TarFile.
getnames
Return the members as a list of their names. It has the same order as the list
returned by
getmembers()
TarFile.
list
verbose
True
members
None
Print a table of contents to
sys.stdout
. If
verbose
is
False
only the names of the members are printed. If it is
True
, output
similar to that of
ls -l
is produced. If optional
members
is
given, it must be a subset of the list returned by
getmembers()
Changed in version 3.5:
Added the
members
parameter.
TarFile.
next
Return the next member of the archive as a
TarInfo
object, when
TarFile
is opened for reading. Return
None
if there is no more
available.
TarFile.
extractall
path
'.'
members
None
numeric_owner
False
filter
None
Extract all members from the archive to the current working directory or
directory
path
. If optional
members
is given, it must be a subset of the
list returned by
getmembers()
. Directory information like owner,
modification time and permissions are set after all members have been extracted.
This is done to work around two problems: A directory’s modification time is
reset each time a file is created in it. And, if a directory’s permissions do
not allow writing, extracting files to it will fail.
If
numeric_owner
is
True
, the uid and gid numbers from the tarfile
are used to set the owner/group for the extracted files. Otherwise, the named
values from the tarfile are used.
The
filter
argument specifies how
members
are modified or rejected
before extraction.
See
Extraction filters
for details.
It is recommended to set this explicitly only if specific
tar
features
are required, or as
filter='data'
to support Python versions with a less
secure default (3.13 and lower).
Warning
Never extract archives from untrusted sources without prior inspection.
Since Python 3.14, the default (
data
) will prevent
the most dangerous security issues.
However, it will not prevent
all
unintended or insecure behavior.
Read the
Extraction filters
section for details.
Changed in version 3.5:
Added the
numeric_owner
parameter.
Changed in version 3.6:
The
path
parameter accepts a
path-like object
Changed in version 3.12:
Added the
filter
parameter.
Changed in version 3.14:
The
filter
parameter now defaults to
'data'
TarFile.
extract
member
path
''
set_attrs
True
numeric_owner
False
filter
None
Extract a member from the archive to the current working directory, using its
full name. Its file information is extracted as accurately as possible.
member
may be a filename or a
TarInfo
object. You can specify a different
directory using
path
path
may be a
path-like object
File attributes (owner, mtime, mode) are set unless
set_attrs
is false.
The
numeric_owner
and
filter
arguments are the same as
for
extractall()
Note
The
extract()
method does not take care of several extraction issues.
In most cases you should consider using the
extractall()
method.
Warning
Never extract archives from untrusted sources without prior inspection.
See the warning for
extractall()
for details.
Changed in version 3.2:
Added the
set_attrs
parameter.
Changed in version 3.5:
Added the
numeric_owner
parameter.
Changed in version 3.6:
The
path
parameter accepts a
path-like object
Changed in version 3.12:
Added the
filter
parameter.
TarFile.
extractfile
member
Extract a member from the archive as a file object.
member
may be
a filename or a
TarInfo
object. If
member
is a regular file or
a link, an
io.BufferedReader
object is returned. For all other
existing members,
None
is returned. If
member
does not appear
in the archive,
KeyError
is raised.
Changed in version 3.3:
Return an
io.BufferedReader
object.
Changed in version 3.13:
The returned
io.BufferedReader
object has the
mode
attribute which is always equal to
'rb'
TarFile.
errorlevel
int
If
errorlevel
is
, errors are ignored when using
TarFile.extract()
and
TarFile.extractall()
Nevertheless, they appear as error messages in the debug output when
debug
is greater than 0.
If
(the default), all
fatal
errors are raised as
OSError
or
FilterError
exceptions. If
, all
non-fatal
errors are raised
as
TarError
exceptions as well.
Some exceptions, e.g. ones caused by wrong argument types or data
corruption, are always raised.
Custom
extraction filters
should raise
FilterError
for
fatal
errors
and
ExtractError
for
non-fatal
ones.
Note that when an exception is raised, the archive may be partially
extracted. It is the user’s responsibility to clean up.
TarFile.
extraction_filter
Added in version 3.12.
The
extraction filter
used
as a default for the
filter
argument of
extract()
and
extractall()
The attribute may be
None
or a callable.
String names are not allowed for this attribute, unlike the
filter
argument to
extract()
If
extraction_filter
is
None
(the default), extraction methods
will use the
data
filter by default.
The attribute may be set on instances or overridden in subclasses.
It also is possible to set it on the
TarFile
class itself to set a
global default, although, since it affects all uses of
tarfile
it is best practice to only do so in top-level applications or
site
configuration
To set a global default this way, a filter function needs to be wrapped in
staticmethod()
to prevent injection of a
self
argument.
Changed in version 3.14:
The default filter is set to
data
which disallows some dangerous features such as links to absolute paths
or paths outside of the destination.
Previously, the default was equivalent to
fully_trusted
TarFile.
add
name
arcname
None
recursive
True
filter
None
Add the file
name
to the archive.
name
may be any type of file
(directory, fifo, symbolic link, etc.). If given,
arcname
specifies an
alternative name for the file in the archive. Directories are added
recursively by default. This can be avoided by setting
recursive
to
False
. Recursion adds entries in sorted order.
If
filter
is given, it
should be a function that takes a
TarInfo
object argument and
returns the changed
TarInfo
object. If it instead returns
None
the
TarInfo
object will be excluded from the
archive. See
Examples
for an example.
Changed in version 3.2:
Added the
filter
parameter.
Changed in version 3.7:
Recursion adds entries in sorted order.
TarFile.
addfile
tarinfo
fileobj
None
Add the
TarInfo
object
tarinfo
to the archive. If
tarinfo
represents
a non zero-size regular file, the
fileobj
argument should be a
binary file
and
tarinfo.size
bytes are read from it and added to the archive. You can
create
TarInfo
objects directly, or by using
gettarinfo()
Changed in version 3.13:
fileobj
must be given for non-zero-sized regular files.
TarFile.
gettarinfo
name
None
arcname
None
fileobj
None
Create a
TarInfo
object from the result of
os.stat()
or
equivalent on an existing file. The file is either named by
name
, or
specified as a
file object
fileobj
with a file descriptor.
name
may be a
path-like object
. If
given,
arcname
specifies an alternative name for the file in the
archive, otherwise, the name is taken from
fileobj
’s
name
attribute, or the
name
argument. The name
should be a text string.
You can modify
some of the
TarInfo
’s attributes before you add it using
addfile()
If the file object is not an ordinary file object positioned at the
beginning of the file, attributes such as
size
may need
modifying. This is the case for objects such as
GzipFile
The
name
may also be modified, in which case
arcname
could be a dummy string.
Changed in version 3.6:
The
name
parameter accepts a
path-like object
TarFile.
close
Close the
TarFile
. In write mode, two finishing zero blocks are
appended to the archive.
TarFile.
pax_headers
dict
A dictionary containing key-value pairs of pax global headers.
TarInfo Objects
TarInfo
object represents one member in a
TarFile
. Aside
from storing all required attributes of a file (like file type, size, time,
permissions, owner etc.), it provides some useful methods to determine its type.
It does
not
contain the file’s data itself.
TarInfo
objects are returned by
TarFile
’s methods
getmember()
getmembers()
and
gettarinfo()
Modifying the objects returned by
getmember()
or
getmembers()
will affect all subsequent
operations on the archive.
For cases where this is unwanted, you can use
copy.copy()
or
call the
replace()
method to create a modified copy in one step.
Several attributes can be set to
None
to indicate that a piece of metadata
is unused or unknown.
Different
TarInfo
methods handle
None
differently:
The
extract()
or
extractall()
methods will
ignore the corresponding metadata, leaving it set to a default.
addfile()
will fail.
list()
will print a placeholder string.
class
tarfile.
TarInfo
name
''
Create a
TarInfo
object.
classmethod
TarInfo.
frombuf
buf
encoding
errors
Create and return a
TarInfo
object from string buffer
buf
Raises
HeaderError
if the buffer is invalid.
classmethod
TarInfo.
fromtarfile
tarfile
Read the next member from the
TarFile
object
tarfile
and return it as
TarInfo
object.
TarInfo.
tobuf
format
DEFAULT_FORMAT
encoding
ENCODING
errors
'surrogateescape'
Create a string buffer from a
TarInfo
object. For information on the
arguments see the constructor of the
TarFile
class.
Changed in version 3.2:
Use
'surrogateescape'
as the default for the
errors
argument.
TarInfo
object has the following public data attributes:
TarInfo.
name
str
Name of the archive member.
TarInfo.
size
int
Size in bytes.
TarInfo.
mtime
int
float
Time of last modification in seconds since the
epoch
as in
os.stat_result.st_mtime
Changed in version 3.12:
Can be set to
None
for
extract()
and
extractall()
, causing extraction to skip applying this
attribute.
TarInfo.
mode
int
Permission bits, as for
os.chmod()
Changed in version 3.12:
Can be set to
None
for
extract()
and
extractall()
, causing extraction to skip applying this
attribute.
TarInfo.
type
File type.
type
is usually one of these constants:
REGTYPE
AREGTYPE
LNKTYPE
SYMTYPE
DIRTYPE
FIFOTYPE
CONTTYPE
CHRTYPE
BLKTYPE
GNUTYPE_SPARSE
. To determine the type of a
TarInfo
object
more conveniently, use the
is*()
methods below.
TarInfo.
linkname
str
Name of the target file name, which is only present in
TarInfo
objects
of type
LNKTYPE
and
SYMTYPE
For symbolic links (
SYMTYPE
), the
linkname
is relative to the directory
that contains the link.
For hard links (
LNKTYPE
), the
linkname
is relative to the root of
the archive.
TarInfo.
uid
int
User ID of the user who originally stored this member.
Changed in version 3.12:
Can be set to
None
for
extract()
and
extractall()
, causing extraction to skip applying this
attribute.
TarInfo.
gid
int
Group ID of the user who originally stored this member.
Changed in version 3.12:
Can be set to
None
for
extract()
and
extractall()
, causing extraction to skip applying this
attribute.
TarInfo.
uname
str
User name.
Changed in version 3.12:
Can be set to
None
for
extract()
and
extractall()
, causing extraction to skip applying this
attribute.
TarInfo.
gname
str
Group name.
Changed in version 3.12:
Can be set to
None
for
extract()
and
extractall()
, causing extraction to skip applying this
attribute.
TarInfo.
chksum
int
Header checksum.
TarInfo.
devmajor
int
Device major number.
TarInfo.
devminor
int
Device minor number.
TarInfo.
offset
int
The tar header starts here.
TarInfo.
offset_data
int
The file’s data starts here.
TarInfo.
sparse
Sparse member information.
TarInfo.
pax_headers
dict
A dictionary containing key-value pairs of an associated pax extended header.
TarInfo.
replace
name
...
mtime
...
mode
...
linkname
...
uid
...
gid
...
uname
...
gname
...
deep
True
Added in version 3.12.
Return a
new
copy of the
TarInfo
object with the given attributes
changed. For example, to return a
TarInfo
with the group name set to
'staff'
, use:
new_tarinfo
old_tarinfo
replace
gname
'staff'
By default, a deep copy is made.
If
deep
is false, the copy is shallow, i.e.
pax_headers
and any custom attributes are shared with the original
TarInfo
object.
TarInfo
object also provides some convenient query methods:
TarInfo.
isfile
Return
True
if the
TarInfo
object is a regular file.
TarInfo.
isreg
Same as
isfile()
TarInfo.
isdir
Return
True
if it is a directory.
TarInfo.
issym
Return
True
if it is a symbolic link.
TarInfo.
islnk
Return
True
if it is a hard link.
TarInfo.
ischr
Return
True
if it is a character device.
TarInfo.
isblk
Return
True
if it is a block device.
TarInfo.
isfifo
Return
True
if it is a FIFO.
TarInfo.
isdev
Return
True
if it is one of character device, block device or FIFO.
Extraction filters
Added in version 3.12.
The
tar
format is designed to capture all details of a UNIX-like filesystem,
which makes it very powerful.
Unfortunately, the features make it easy to create tar files that have
unintended – and possibly malicious – effects when extracted.
For example, extracting a tar file can overwrite arbitrary files in various
ways (e.g. by using absolute paths,
..
path components, or symlinks that
affect later members).
In most cases, the full functionality is not needed.
Therefore,
tarfile
supports extraction filters: a mechanism to limit
functionality, and thus mitigate some of the security issues.
Warning
None of the available filters blocks
all
dangerous archive features.
Never extract archives from untrusted sources without prior inspection.
See also
Hints for further verification
See also
PEP 706
Contains further motivation and rationale behind the design.
The
filter
argument to
TarFile.extract()
or
extractall()
can be:
the string
'fully_trusted'
: Honor all metadata as specified in the
archive.
Should be used if the user trusts the archive completely, or implements
their own complex verification.
the string
'tar'
: Honor most
tar
-specific features (i.e. features of
UNIX-like filesystems), but block features that are very likely to be
surprising or malicious. See
tar_filter()
for details.
the string
'data'
: Ignore or block most features specific to UNIX-like
filesystems. Intended for extracting cross-platform data archives.
See
data_filter()
for details.
None
(default): Use
TarFile.extraction_filter
If that is also
None
(the default), the
'data'
filter will be used.
Changed in version 3.14:
The default filter is set to
data
Previously, the default was equivalent to
fully_trusted
A callable which will be called for each extracted member with a
TarInfo
describing the member and the destination
path to where the archive is extracted (i.e. the same path is used for all
members):
filter
member
TarInfo
path
str
->
TarInfo
None
The callable is called just before each member is extracted, so it can
take the current state of the disk into account.
It can:
return a
TarInfo
object which will be used instead of the metadata
in the archive, or
return
None
, in which case the member will be skipped, or
raise an exception to abort the operation or skip the member,
depending on
errorlevel
Note that when extraction is aborted,
extractall()
may leave
the archive partially extracted. It does not attempt to clean up.
Default named filters
The pre-defined, named filters are available as functions, so they can be
reused in custom filters:
tarfile.
fully_trusted_filter
member
path
Return
member
unchanged.
This implements the
'fully_trusted'
filter.
tarfile.
tar_filter
member
path
Implements the
'tar'
filter.
Strip leading slashes (
and
os.sep
) from filenames.
Refuse
to extract files with absolute
paths (in case the name is absolute
even after stripping slashes, e.g.
C:/foo
on Windows).
This raises
AbsolutePathError
Refuse
to extract files whose absolute
path (after following symlinks) would end up outside the destination.
This raises
OutsideDestinationError
Clear high mode bits (setuid, setgid, sticky) and group/other write bits
S_IWGRP
S_IWOTH
).
Return the modified
TarInfo
member.
tarfile.
data_filter
member
path
Implements the
'data'
filter.
In addition to what
tar_filter
does:
Normalize link targets (
TarInfo.linkname
) using
os.path.normpath()
Note that this removes internal
..
components, which may change the
meaning of the link if the path in
TarInfo.linkname
traverses
symbolic links.
Refuse
to extract links (hard or soft)
that link to absolute paths, or ones that link outside the destination.
This raises
AbsoluteLinkError
or
LinkOutsideDestinationError
Note that such files are refused even on platforms that do not support
symbolic links.
Refuse
to extract device files
(including pipes).
This raises
SpecialFileError
For regular files, including hard links:
Set the owner read and write permissions
S_IRUSR
S_IWUSR
).
Remove the group & other executable permission
S_IXGRP
S_IXOTH
if the owner doesn’t have it (
S_IXUSR
).
For other files (directories), set
mode
to
None
, so
that extraction methods skip applying permission bits.
Set user and group info (
uid
gid
uname
gname
to
None
, so that extraction methods skip setting it.
Return the modified
TarInfo
member.
Note that this filter does not block
all
dangerous archive features.
See
Hints for further verification
for details.
Changed in version 3.14:
Link targets are now normalized.
Filter errors
When a filter refuses to extract a file, it will raise an appropriate exception,
a subclass of
FilterError
This will abort the extraction if
TarFile.errorlevel
is 1 or more.
With
errorlevel=0
the error will be logged and the member will be skipped,
but extraction will continue.
Hints for further verification
Even with
filter='data'
tarfile
is not suited for extracting untrusted
files without prior inspection.
Among other issues, the pre-defined filters do not prevent denial-of-service
attacks. Users should do additional checks.
Here is an incomplete list of things to consider:
Extract to a
new
temporary
directory
to prevent e.g. exploiting pre-existing links, and to make it easier to
clean up after a failed extraction.
Disallow symbolic links if you do not need the functionality.
When working with untrusted data, use external (e.g. OS-level) limits on
disk, memory and CPU usage.
Check filenames against an allow-list of characters
(to filter out control characters, confusables, foreign path separators,
and so on).
Check that filenames have expected extensions (discouraging files that
execute when you “click on them”, or extension-less files like Windows
special device names).
Limit the number of extracted files, total size of extracted data,
filename length (including symlink length), and size of individual files.
Check for files that would be shadowed on case-insensitive filesystems.
Also note that:
Tar files may contain multiple versions of the same file.
Later ones are expected to overwrite any earlier ones.
This feature is crucial to allow updating tape archives, but can be abused
maliciously.
tarfile
does not protect against issues with “live” data,
e.g. an attacker tinkering with the destination (or source) directory while
extraction (or archiving) is in progress.
Supporting older Python versions
Extraction filters were added to Python 3.12, but may be backported to older
versions as security updates.
To check whether the feature is available, use e.g.
hasattr(tarfile,
'data_filter')
rather than checking the Python version.
The following examples show how to support Python versions with and without
the feature.
Note that setting
extraction_filter
will affect any subsequent operations.
Fully trusted archive:
my_tarfile
extraction_filter
lambda
member
path
member
my_tarfile
extractall
()
Use the
'data'
filter if available, but revert to Python 3.11 behavior
'fully_trusted'
) if this feature is not available:
my_tarfile
extraction_filter
getattr
tarfile
'data_filter'
lambda
member
path
member
))
my_tarfile
extractall
()
Use the
'data'
filter;
fail
if it is not available:
my_tarfile
extractall
filter
tarfile
data_filter
or:
my_tarfile
extraction_filter
tarfile
data_filter
my_tarfile
extractall
()
Use the
'data'
filter;
warn
if it is not available:
if
hasattr
tarfile
'data_filter'
):
my_tarfile
extractall
filter
'data'
else
# remove this when no longer needed
warn_the_user
'Extracting may be unsafe; consider updating Python'
my_tarfile
extractall
()
Stateful extraction filter example
While
tarfile
’s extraction methods take a simple
filter
callable,
custom filters may be more complex objects with an internal state.
It may be useful to write these as context managers, to be used like this:
with
StatefulFilter
()
as
filter_func
tar
extractall
path
filter
filter_func
Such a filter can be written as, for example:
class
StatefulFilter
def
__init__
self
):
self
file_count
def
__enter__
self
):
return
self
def
__call__
self
member
path
):
self
file_count
+=
return
member
def
__exit__
self
exc_info
):
self
file_count
files extracted'
Command-Line Interface
Added in version 3.4.
The
tarfile
module provides a simple command-line interface to interact
with tar archives.
If you want to create a new tar archive, specify its name after the
-c
option and then list the filename(s) that should be included:
python
-m
tarfile
-c
monty.tar
spam.txt
eggs.txt
Passing a directory is also acceptable:
python
-m
tarfile
-c
monty.tar
life-of-brian_1979/
If you want to extract a tar archive into the current directory, use
the
-e
option:
python
-m
tarfile
-e
monty.tar
You can also extract a tar archive into a different directory by passing the
directory’s name:
python
-m
tarfile
-e
monty.tar
other-dir/
For a list of the files in a tar archive, use the
-l
option:
python
-m
tarfile
-l
monty.tar
Command-line options
-l

--list

List files in a tarfile.
-c


...

--create


...

Create tarfile from source files.
-e

[]
--extract

[]
Extract tarfile into the current directory if
output_dir
is not specified.
-t

--test

Test whether the tarfile is valid or not.
-v
--verbose
Verbose output.
--filter

Specifies the
filter
for
--extract
See
Extraction filters
for details.
Only string names are accepted (that is,
fully_trusted
tar
and
data
).
Examples
Reading examples
How to extract an entire tar archive to the current working directory:
import
tarfile
tar
tarfile
open
"sample.tar.gz"
tar
extractall
filter
'data'
tar
close
()
How to extract a subset of a tar archive with
TarFile.extractall()
using
a generator function instead of a list:
import
os
import
tarfile
def
py_files
members
):
for
tarinfo
in
members
if
os
path
splitext
tarinfo
name
)[
==
".py"
yield
tarinfo
tar
tarfile
open
"sample.tar.gz"
tar
extractall
members
py_files
tar
))
tar
close
()
How to read a gzip compressed tar archive and display some member information:
import
tarfile
tar
tarfile
open
"sample.tar.gz"
"r:gz"
for
tarinfo
in
tar
tarinfo
name
"is"
tarinfo
size
"bytes in size and is "
end
""
if
tarinfo
isreg
():
"a regular file."
elif
tarinfo
isdir
():
"a directory."
else
"something else."
tar
close
()
Writing examples
How to create an uncompressed tar archive from a list of filenames:
import
tarfile
tar
tarfile
open
"sample.tar"
"w"
for
name
in
"foo"
"bar"
"quux"
]:
tar
add
name
tar
close
()
The same example using the
with
statement:
import
tarfile
with
tarfile
open
"sample.tar"
"w"
as
tar
for
name
in
"foo"
"bar"
"quux"
]:
tar
add
name
How to create and write an archive to stdout using
sys.stdout.buffer
in the
fileobj
parameter
in
TarFile.add()
import
sys
import
tarfile
with
tarfile
open
"sample.tar.gz"
"w|gz"
fileobj
sys
stdout
buffer
as
tar
for
name
in
"foo"
"bar"
"quux"
]:
tar
add
name
How to create an archive and reset the user information using the
filter
parameter in
TarFile.add()
import
tarfile
def
reset
tarinfo
):
tarinfo
uid
tarinfo
gid
tarinfo
uname
tarinfo
gname
"root"
return
tarinfo
tar
tarfile
open
"sample.tar.gz"
"w:gz"
tar
add
"foo"
filter
reset
tar
close
()
Supported tar formats
There are three tar formats that can be created with the
tarfile
module:
The POSIX.1-1988 ustar format (
USTAR_FORMAT
). It supports filenames
up to a length of at best 256 characters and linknames up to 100 characters.
The maximum file size is 8 GiB. This is an old and limited but widely
supported format.
The GNU tar format (
GNU_FORMAT
). It supports long filenames and
linknames, files bigger than 8 GiB and sparse files. It is the de facto
standard on GNU/Linux systems.
tarfile
fully supports the GNU tar
extensions for long names, sparse file support is read-only.
The POSIX.1-2001 pax format (
PAX_FORMAT
). It is the most flexible
format with virtually no limits. It supports long filenames and linknames, large
files and stores pathnames in a portable way. Modern tar implementations,
including GNU tar, bsdtar/libarchive and star, fully support extended
pax
features; some old or unmaintained libraries may not, but should treat
pax
archives as if they were in the universally supported
ustar
format.
It is the current default format for new archives.
It extends the existing
ustar
format with extra headers for information
that cannot be stored otherwise. There are two flavours of pax headers:
Extended headers only affect the subsequent file header, global
headers are valid for the complete archive and affect all following files.
All the data in a pax header is encoded in
UTF-8
for portability reasons.
There are some more variants of the tar format which can be read, but not
created:
The ancient V7 format. This is the first tar format from Unix Seventh Edition,
storing only regular files and directories. Names must not be longer than 100
characters, there is no user/group name information. Some archives have
miscalculated header checksums in case of fields with non-ASCII characters.
The SunOS tar extended format. This format is a variant of the POSIX.1-2001
pax format, but is not compatible.
Unicode issues
The tar format was originally conceived to make backups on tape drives with the
main focus on preserving file system information. Nowadays tar archives are
commonly used for file distribution and exchanging archives over networks. One
problem of the original format (which is the basis of all other formats) is
that there is no concept of supporting different character encodings. For
example, an ordinary tar archive created on a
UTF-8
system cannot be read
correctly on a
Latin-1
system if it contains non-
ASCII
characters. Textual
metadata (like filenames, linknames, user/group names) will appear damaged.
Unfortunately, there is no way to autodetect the encoding of an archive. The
pax format was designed to solve this problem. It stores non-ASCII metadata
using the universal character encoding
UTF-8
The details of character conversion in
tarfile
are controlled by the
encoding
and
errors
keyword arguments of the
TarFile
class.
encoding
defines the character encoding to use for the metadata in the
archive. The default value is
sys.getfilesystemencoding()
or
'ascii'
as a fallback. Depending on whether the archive is read or written, the
metadata must be either decoded or encoded. If
encoding
is not set
appropriately, this conversion may fail.
The
errors
argument defines how characters are treated that cannot be
converted. Possible values are listed in section
Error Handlers
The default scheme is
'surrogateescape'
which Python also uses for its
file system calls, see
File Names, Command Line Arguments, and Environment Variables
For
PAX_FORMAT
archives (the default),
encoding
is generally not needed
because all the metadata is stored using
UTF-8
encoding
is only used in
the rare cases when binary pax headers are decoded or when strings with
surrogate characters are stored.
Table of Contents
tarfile
— Read and write tar archive files
TarFile Objects
TarInfo Objects
Extraction filters
Default named filters
Filter errors
Hints for further verification
Supporting older Python versions
Stateful extraction filter example
Command-Line Interface
Command-line options
Examples
Reading examples
Writing examples
Supported tar formats
Unicode issues
Previous topic
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— Work with ZIP archives
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Python
3.14.4 Documentation
The Python Standard Library
Data Compression and Archiving
tarfile
— Read and write tar archive files
Theme
2001 Python Software Foundation.
This page is licensed under the Python Software Foundation License Version 2.
Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
See
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