This module provides generic, low- and high-level interfaces for
creating temporary files and directories. The interfaces listed
as "safe" just below can be used without fear of race conditions.
Those listed as "unsafe" cannot, and are provided for backward
This module also provides some data items to the user:
TMP_MAX - maximum number of names that will be tried before
template - the default prefix for all temporary names.
You may change this to control the default prefix.
tempdir - If this is set to a string before the first use of
any routine from this module, it will be considered as
another candidate location to store temporary files.
"NamedTemporaryFile", "TemporaryFile", # high level safe interfaces
"mkstemp", "mkdtemp", # low level safe interfaces
"mktemp", # deprecated unsafe interface
"TMP_MAX", "gettempprefix", # constants
from random
import Random
as _Random
import Carbon
.Folder
as _Folder
import Carbon
.Folders
as _Folders
flags
= _fcntl
.fcntl(fd
, _fcntl
.F_GETFD
, 0)
# flags read successfully, modify
flags |
= _fcntl
.FD_CLOEXEC
_fcntl
.fcntl(fd
, _fcntl
.F_SETFD
, flags
)
import dummy_thread
as _thread
_allocate_lock
= _thread
.allocate_lock
_text_openflags
= _os
.O_RDWR | _os
.O_CREAT | _os
.O_EXCL
if hasattr(_os
, 'O_NOINHERIT'):
_text_openflags |
= _os
.O_NOINHERIT
if hasattr(_os
, 'O_NOFOLLOW'):
_text_openflags |
= _os
.O_NOFOLLOW
_bin_openflags
= _text_openflags
if hasattr(_os
, 'O_BINARY'):
_bin_openflags |
= _os
.O_BINARY
if hasattr(_os
, 'TMP_MAX'):
_once_lock
= _allocate_lock()
if hasattr(_os
, "lstat"):
elif hasattr(_os
, "stat"):
# Fallback. All we need is something that raises os.error if the
class _RandomNameSequence
:
"""An instance of _RandomNameSequence generates an endless
sequence of unpredictable strings which can safely be incorporated
into file names. Each string is six characters long. Multiple
threads can safely use the same instance at the same time.
_RandomNameSequence is an iterator."""
characters
= ("abcdefghijklmnopqrstuvwxyz" +
"ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
self
.mutex
= _allocate_lock()
self
.normcase
= _os
.path
.normcase
letters
= [choose(c
) for dummy
in "123456"]
return self
.normcase(''.join(letters
))
def _candidate_tempdir_list():
"""Generate a list of candidate temporary directories which
_get_default_tempdir will try."""
# First, try the environment.
for envname
in 'TMPDIR', 'TEMP', 'TMP':
dirname
= _os
.getenv(envname
)
if dirname
: dirlist
.append(dirname
)
# Failing that, try OS-specific locations.
fsr
= _Folder
.FSFindFolder(_Folders
.kOnSystemDisk
,
_Folders
.kTemporaryFolderType
, 1)
dirname
= fsr
.as_pathname()
elif _os
.name
== 'riscos':
dirname
= _os
.getenv('Wimp$ScrapDir')
if dirname
: dirlist
.append(dirname
)
dirlist
.extend([ r
'c:\temp', r
'c:\tmp', r
'\temp', r
'\tmp' ])
dirlist
.extend([ '/tmp', '/var/tmp', '/usr/tmp' ])
# As a last resort, the current directory.
dirlist
.append(_os
.getcwd())
except (AttributeError, _os
.error
):
dirlist
.append(_os
.curdir
)
def _get_default_tempdir():
"""Calculate the default directory to use for temporary files.
This routine should be called exactly once.
We determine whether or not a candidate temp dir is usable by
trying to create and write to a file in that directory. If this
is successful, the test file is deleted. To prevent denial of
service, the name of the test file must be randomized."""
namer
= _RandomNameSequence()
dirlist
= _candidate_tempdir_list()
dir = _os
.path
.normcase(_os
.path
.abspath(dir))
# Try only a few names per directory.
filename
= _os
.path
.join(dir, name
)
fd
= _os
.open(filename
, flags
, 0600)
except (OSError, IOError), e
:
if e
[0] != _errno
.EEXIST
:
break # no point trying more names in this directory
raise IOError, (_errno
.ENOENT
,
("No usable temporary directory found in %s" % dirlist
))
def _get_candidate_names():
"""Common setup sequence for all user-callable interfaces."""
if _name_sequence
is None:
if _name_sequence
is None:
_name_sequence
= _RandomNameSequence()
def _mkstemp_inner(dir, pre
, suf
, flags
):
"""Code common to mkstemp, TemporaryFile, and NamedTemporaryFile."""
names
= _get_candidate_names()
for seq
in xrange(TMP_MAX
):
file = _os
.path
.join(dir, pre
+ name
+ suf
)
fd
= _os
.open(file, flags
, 0600)
return (fd
, _os
.path
.abspath(file))
if e
.errno
== _errno
.EEXIST
:
raise IOError, (_errno
.EEXIST
, "No usable temporary file name found")
# User visible interfaces.
"""Accessor for tempdir.template."""
"""Accessor for tempdir.tempdir."""
tempdir
= _get_default_tempdir()
def mkstemp(suffix
="", prefix
=template
, dir=None, text
=False):
"""mkstemp([suffix, [prefix, [dir, [text]]]])
User-callable function to create and return a unique temporary
file. The return value is a pair (fd, name) where fd is the
file descriptor returned by os.open, and name is the filename.
If 'suffix' is specified, the file name will end with that suffix,
otherwise there will be no suffix.
If 'prefix' is specified, the file name will begin with that prefix,
otherwise a default prefix is used.
If 'dir' is specified, the file will be created in that directory,
otherwise a default directory is used.
If 'text' is specified and true, the file is opened in text
mode. Else (the default) the file is opened in binary mode. On
some operating systems, this makes no difference.
The file is readable and writable only by the creating user ID.
If the operating system uses permission bits to indicate whether a
file is executable, the file is executable by no one. The file
descriptor is not inherited by children of this process.
Caller is responsible for deleting the file when done with it.
return _mkstemp_inner(dir, prefix
, suffix
, flags
)
def mkdtemp(suffix
="", prefix
=template
, dir=None):
"""mkdtemp([suffix, [prefix, [dir]]])
User-callable function to create and return a unique temporary
directory. The return value is the pathname of the directory.
Arguments are as for mkstemp, except that the 'text' argument is
The directory is readable, writable, and searchable only by the
Caller is responsible for deleting the directory when done with it.
names
= _get_candidate_names()
for seq
in xrange(TMP_MAX
):
file = _os
.path
.join(dir, prefix
+ name
+ suffix
)
if e
.errno
== _errno
.EEXIST
:
raise IOError, (_errno
.EEXIST
, "No usable temporary directory name found")
def mktemp(suffix
="", prefix
=template
, dir=None):
"""mktemp([suffix, [prefix, [dir]]])
User-callable function to return a unique temporary file name. The
Arguments are as for mkstemp, except that the 'text' argument is
This function is unsafe and should not be used. The file name
refers to a file that did not exist at some point, but by the time
you get around to creating it, someone else may have beaten you to
## from warnings import warn as _warn
## _warn("mktemp is a potential security risk to your program",
## RuntimeWarning, stacklevel=2)
names
= _get_candidate_names()
for seq
in xrange(TMP_MAX
):
file = _os
.path
.join(dir, prefix
+ name
+ suffix
)
raise IOError, (_errno
.EEXIST
, "No usable temporary filename found")
class _TemporaryFileWrapper
:
"""Temporary file wrapper
This class provides a wrapper around files opened for
temporary use. In particular, it seeks to automatically
remove the file when it is no longer needed.
def __init__(self
, file, name
):
self
.close_called
= False
def __getattr__(self
, name
):
file = self
.__dict
__['file']
# NT provides delete-on-close as a primitive, so we don't need
# the wrapper to do anything special. We still use it so that
# file.name is useful (i.e. not "(fdopen)") with NamedTemporaryFile.
# Cache the unlinker so we don't get spurious errors at
# shutdown when the module-level "os" is None'd out. Note
# that this must be referenced as self.unlink, because the
# name TemporaryFileWrapper may also get None'd out before
if not self
.close_called
:
def NamedTemporaryFile(mode
='w+b', bufsize
=-1, suffix
="",
prefix
=template
, dir=None):
"""Create and return a temporary file.
'prefix', 'suffix', 'dir' -- as for mkstemp.
'mode' -- the mode argument to os.fdopen (default "w+b").
'bufsize' -- the buffer size argument to os.fdopen (default -1).
The file is created as mkstemp() would do it.
Returns an object with a file-like interface; the name of the file
is accessible as file.name. The file will be automatically deleted
# Setting O_TEMPORARY in the flags causes the OS to delete
# the file when it is closed. This is only supported by Windows.
(fd
, name
) = _mkstemp_inner(dir, prefix
, suffix
, flags
)
file = _os
.fdopen(fd
, mode
, bufsize
)
return _TemporaryFileWrapper(file, name
)
if _os
.name
!= 'posix' or _os
.sys
.platform
== 'cygwin':
# On non-POSIX and Cygwin systems, assume that we cannot unlink a file
TemporaryFile
= NamedTemporaryFile
def TemporaryFile(mode
='w+b', bufsize
=-1, suffix
="",
prefix
=template
, dir=None):
"""Create and return a temporary file.
'prefix', 'suffix', 'directory' -- as for mkstemp.
'mode' -- the mode argument to os.fdopen (default "w+b").
'bufsize' -- the buffer size argument to os.fdopen (default -1).
The file is created as mkstemp() would do it.
Returns an object with a file-like interface. The file has no
name, and will cease to exist when it is closed.
(fd
, name
) = _mkstemp_inner(dir, prefix
, suffix
, flags
)
return _os
.fdopen(fd
, mode
, bufsize
)