diff options
Diffstat (limited to 'Doc')
| -rw-r--r-- | Doc/whatsnew/3.3.rst | 155 |
1 files changed, 82 insertions, 73 deletions
diff --git a/Doc/whatsnew/3.3.rst b/Doc/whatsnew/3.3.rst index 340ad8b..eada544 100644 --- a/Doc/whatsnew/3.3.rst +++ b/Doc/whatsnew/3.3.rst @@ -786,6 +786,20 @@ aforementioned annoyances. (contributed by Antoine Pitrou in :issue:`9260`.) +Builtin functions +================= + + * :func:`open` gets a new *opener* parameter: the underlying file descriptor + for the file object is then obtained by calling *opener* with (*file*, + *flags*). It can be used to use custom flags like :data:`os.O_CLOEXEC` for + example. The ``'x'`` mode was added: open for exclusive creation, failing if + the file already exists. + * :func:`print`: added the *flush* keyword argument. If the *flush* keyword + argument is true, the stream is forcibly flushed. + * :func:`hash`: hash randomization is enabled by default, see + :meth:`object.__hash__` and :envvar:`PYTHONHASHSEED`. + + New and Improved Modules ======================== @@ -1163,6 +1177,29 @@ os (Patch submitted by Ross Lagerwall and Giampaolo Rodolà in :issue:`10882`.) +* To avoid race conditions like symlink attacks and issues with temporary + files and directories, it is more reliable (and also faster) to manipulate + file descriptors instead of file names. Python 3.3 enhances existing functions + and introduces new functions to work on file descriptors. + + - The :mod:`os` module has a new :func:`~os.fwalk` function similar to + :func:`~os.walk` except that it also yields file descriptors referring to the + directories visited. This is especially useful to avoid symlink races. + + - The following functions get new optional *dir_fd* (:ref:`paths relative to + directory descriptors <dir_fd>`) and/or *follow_symlinks* (:ref:`not + following symlinks <follow_symlinks>`): + :func:`~os.access`, :func:`~os.chflags`, :func:`~os.chmod`, :func:`~os.chown`, + :func:`~os.link`, :func:`~os.lstat`, :func:`~os.mkdir`, :func:`~os.mkfifo`, + :func:`~os.mknod`, :func:`~os.open`, :func:`~os.readlink`, :func:`~os.remove`, + :func:`~os.rename`, :func:`~os.replace`, :func:`~os.rmdir`, :func:`~os.stat`, + :func:`~os.symlink`, :func:`~os.unlink`, :func:`~os.utime`. + + - The following functions now support a file descriptor for their path argument: + :func:`~os.chdir`, :func:`~os.chmod`, :func:`~os.chown`, + :func:`~os.execve`, :func:`~os.listdir`, :func:`~os.pathconf`, + :func:`~os.stat`, :func:`~os.statvfs`, :func:`~os.utime`. + * The :mod:`os` module has two new functions: :func:`~os.getpriority` and :func:`~os.setpriority`. They can be used to get or set process niceness/priority in a fashion similar to :func:`os.nice` but extended to all @@ -1170,10 +1207,6 @@ os (Patch submitted by Giampaolo Rodolà in :issue:`10784`.) -* The :mod:`os` module has a new :func:`~os.fwalk` function similar to - :func:`~os.walk` except that it also yields file descriptors referring to the - directories visited. This is especially useful to avoid symlink races. - * The new :func:`os.replace` function allows cross-platform renaming of a file with overwriting the destination. With :func:`os.rename`, an existing destination file is overwritten under POSIX, but raises an error under @@ -1181,78 +1214,51 @@ os (Contributed by Antoine Pitrou in :issue:`8828`.) * The new :func:`os.get_terminal_size` function queries the size of the - terminal attached to a file descriptor. + terminal attached to a file descriptor. See also + :func:`shutil.get_terminal_size`. (Contributed by Zbigniew Jędrzejewski-Szmek in :issue:`13609`.) .. XXX sort out this mess after beta1 - * "at" functions (:issue:`4761`): - - * :func:`~os.faccessat` - * :func:`~os.fchmodat` - * :func:`~os.fchownat` - * :func:`~os.fstatat` - * :func:`~os.futimesat` - * :func:`~os.linkat` - * :func:`~os.mkdirat` - * :func:`~os.mkfifoat` - * :func:`~os.mknodat` - * :func:`~os.openat` - * :func:`~os.readlinkat` - * :func:`~os.renameat` - * :func:`~os.symlinkat` - * :func:`~os.unlinkat` - * :func:`~os.utimensat` - - * extended attributes (:issue:`12720`): - - * :func:`~os.fgetxattr` - * :func:`~os.flistxattr` - * :func:`~os.fremovexattr` - * :func:`~os.fsetxattr` - * :func:`~os.getxattr` - * :func:`~os.lgetxattr` - * :func:`~os.listxattr` - * :func:`~os.llistxattr` - * :func:`~os.lremovexattr` - * :func:`~os.lsetxattr` - * :func:`~os.removexattr` - * :func:`~os.setxattr` - - * Scheduler functions (:issue:`12655`): - - * :func:`~os.sched_get_priority_max` - * :func:`~os.sched_get_priority_min` - * :func:`~os.sched_getaffinity` - * :func:`~os.sched_getparam` - * :func:`~os.sched_getscheduler` - * :func:`~os.sched_rr_get_interval` - * :func:`~os.sched_setaffinity` - * :func:`~os.sched_setparam` - * :func:`~os.sched_setscheduler` - * :func:`~os.sched_yield` - - * Add some extra posix functions to the os module (:issue:`10812`): - - * :func:`~os.fexecve` - * :func:`~os.futimens` - * :func:`~os.futimes` - * :func:`~os.lockf` - * :func:`~os.lutimes` - * :func:`~os.posix_fadvise` - * :func:`~os.posix_fallocate` - * :func:`~os.pread` - * :func:`~os.pwrite` - * :func:`~os.readv` - * :func:`~os.sync` - * :func:`~os.truncate` - * :func:`~os.waitid` - * :func:`~os.writev` - - * Other new functions: - - * :func:`~os.flistdir` (:issue:`10755`) - * :func:`~os.getgrouplist` (:issue:`9344`) +* New functions to support Linux extended attributes: + :func:`~os.getxattr`, :func:`~os.listxattr`, :func:`~os.removexattr`, + :func:`~os.setxattr`. + +* New interface to the scheduler. These functions + control how a process is allocated CPU time by the operating system. New + functions: + :func:`~os.sched_get_priority_max`, :func:`~os.sched_get_priority_min`, + :func:`~os.sched_getaffinity`, :func:`~os.sched_getparam`, + :func:`~os.sched_getscheduler`, :func:`~os.sched_rr_get_interval`, + :func:`~os.sched_setaffinity`, :func:`~os.sched_setparam`, + :func:`~os.sched_setscheduler`, :func:`~os.sched_yield`, + +* New functions to control the file system: + + * :func:`~os.posix_fadvise`: Announces an intention to access data in a + specific pattern thus allowing the kernel to make optimizations. + * :func:`~os.posix_fallocate`: Ensures that enough disk space is allocated + for a file. + * :func:`~os.sync`: Force write of everything to disk. + +* Add some extra posix functions to the os module: + + * :func:`~os.lockf`: Apply, test or remove a POSIX lock on an open file descriptor. + * :func:`~os.pread`: Read from a file descriptor at an offset, the file + offset remains unchanged. + * :func:`~os.pwrite`: Write to a file descriptor from an offset, leaving + the file offset unchanged. + * :func:`~os.readv`: Read from a file descriptor into a number of writable buffers. + * :func:`~os.truncate`: Truncate the file corresponding to *path*, so that + it is at most *length* bytes in size. + * :func:`~os.waitid`: Wait for the completion of one or more child processes. + * :func:`~os.writev`: Write the contents of *buffers* to a file descriptor, + where *buffers* is an arbitrary sequence of buffers. + * :func:`~os.getgrouplist` (:issue:`9344`): Return list of group ids that + specified user belongs to. + +* :func:`~os.times` and :func:`~os.uname`: Return type changed from a tuple to + a tuple-like object with named attributes. pdb @@ -1614,6 +1620,7 @@ Deprecated Python modules, functions and methods * The behaviour of :func:`time.clock` depends on the platform: use the new :func:`time.perf_counter` or :func:`time.process_time` function instead, depending on your requirements, to have a well defined behaviour. +* The :func:`os.stat_float_times` function is deprecated. Deprecated functions and types of the C API @@ -1690,7 +1697,9 @@ that may require changes to your code. Porting Python code ------------------- -.. XXX add a point about hash randomization and that it's always on in 3.3 +* Hash randomization is enabled by default. Set the :envvar:`PYTHONHASHSEED` + environment variable to ``0`` to disable hash randomization. See also the + :meth:`object.__hash__` method. * :issue:`12326`: On Linux, sys.platform doesn't contain the major version anymore. It is now always 'linux', instead of 'linux2' or 'linux3' depending |