Implement os.statx

Author: jbosboom

Doc/library/os.rst

@@ -3383,6 +3383,137 @@ features:
       Added the :attr:`st_birthtime` member on Windows.
 
 
+.. function:: statx(path, mask, *, dir_fd=None, follow_symlinks=True, sync=None)
+
+   Get the status of a file or file descriptor by performing a :c:func:`!statx`
+   system call on the given path. *path* may be specified as either a string or
+   bytes -- directly or indirectly through the :class:`PathLike` interface --
+   or as an open file descriptor. *mask* is a combination of the module-level
+   :const:`STATX_* <STATX_TYPE>` constants specifying the information to
+   retrieve. Returns a :class:`statx_result` object whose
+   :attr:`~os.statx_result.stx_mask` attribute specifies the information
+   actually retrieved (which may differ from *mask*).
+
+   The optional parameter *sync* controls the freshness of the returned
+   information.  ``sync=True`` requests that the kernel return up-to-date
+   information, even when doing so is expensive (for example, requiring a
+   round trip to the server for a file on a network filesystem).
+   ``sync=False`` requests that the kernel return cached information if
+   available.  ``sync=None`` expresses no preference, in which case the kernel
+   will return information as fresh as :func:`~os.stat` does.
+
+   This function supports :ref:`specifying a file descriptor <path_fd>`,
+   :ref:`paths relative to directory descriptors <dir_fd>`, and
+   :ref:`not following symlinks <follow_symlinks>`.
+
+   .. seealso:: The :manpage:`statx(2)` man page.
+
+   .. availability:: Linux >= 4.11 with glibc >= 2.28.
+
+   .. versionadded:: next
+
+
+.. class:: statx_result
+
+   Object whose attributes correspond roughly to the members of the
+   :c:struct:`!statx` structure. It is used for the result of :func:`os.statx`.
+   :class:`!statx_result` has all of the attributes of :class:`stat_result`
+   available on Linux, but is not a subclass of :class:`stat_result` nor a
+   tuple.  :class:`!statx_result` has the following additional attributes:
+
+   .. attribute:: stx_mask
+
+      Bitmask of :const:`STATX_* <STATX_TYPE>` constants specifying the
+      information retrieved, which may differ from what was requested depending
+      on the filesystem, filesystem type, and kernel version.  All attributes
+      of this class are accessible regardless of the value of
+      :attr:`!stx_mask`, and they may have useful fictitious values.  For
+      example, for a file on a network filesystem, :const:`STATX_UID` and
+      :const:`STATX_GID` may be unset because file ownership on the server is
+      based on an external user database, but :attr:`!st_uid` and
+      :attr:`!st_gid` may contain the IDs of the local user who controls the
+      mount.
+
+   .. attribute:: stx_attributes_mask
+
+      Bitmask of :const:`!STATX_ATTR_* <stat.STATX_ATTR_COMPRESSED>` constants
+      specifying the attributes bits supported for this file.
+
+   .. attribute:: stx_attributes
+
+      Bitmask of :const:`!STATX_ATTR_* <stat.STATX_ATTR_COMPRESSED>` constants
+      specifying the attributes of this file.
+
+   .. attribute:: stx_mnt_id
+
+      Mount ID.
+
+   .. attribute:: stx_dio_mem_align
+
+      Direct I/O memory buffer alignment requirement.
+
+   .. attribute:: stx_dio_offset_align
+
+      Direct I/O file offset alignment requirement.
+
+   .. attribute:: stx_subvol
+
+      Subvolume ID.
+
+   .. attribute:: stx_atomic_write_unit_min
+
+      Minimum size for direct I/O with torn-write protection.
+
+   .. attribute:: stx_atomic_write_unit_max
+
+      Maximum size for direct I/O with torn-write protection.
+
+   .. attribute:: stx_atomic_write_segments_max
+
+      Maximum iovecs for direct I/O with torn-write protection.
+
+   .. attribute:: stx_dio_read_offset_align
+
+      Direct I/O file offset alignment requirement for reads.
+
+   .. attribute:: stx_atomic_write_unit_max_opt
+
+      Maximum optimized size for direct I/O with torn-write protection.
+
+   .. seealso:: The :manpage:`statx(2)` man page.
+
+   .. availability:: Linux >= 4.11 with glibc >= 2.28.
+
+   .. versionadded:: next
+
+
+.. data:: STATX_TYPE
+          STATX_MODE
+          STATX_NLINK
+          STATX_UID
+          STATX_GID
+          STATX_ATIME
+          STATX_MTIME
+          STATX_CTIME
+          STATX_INO
+          STATX_SIZE
+          STATX_BLOCKS
+          STATX_BASIC_STATS
+          STATX_BTIME
+          STATX_MNT_ID
+          STATX_DIOALIGN
+          STATX_MNT_ID_UNIQUE
+          STATX_SUBVOL
+          STATX_WRITE_ATOMIC
+          STATX_DIO_READ_ALIGN
+
+   Bitflags for use as the *mask* parameter to :func:`os.statx`.
+
+   .. availability:: Linux >= 4.11 with glibc >= 2.28.
+
+   .. versionadded:: next
+
+
 .. function:: statvfs(path)
 
    Perform a :c:func:`!statvfs` system call on the given path.  The return value is

Doc/library/stat.rst

@@ -493,3 +493,22 @@ constants, but are not an exhaustive list.
           IO_REPARSE_TAG_APPEXECLINK
 
    .. versionadded:: 3.8
+
+On Linux, the following file attribute constants are available for use when
+testing bits in the :attr:`~os.statx_result.stx_attributes` and
+:attr:`~os.statx_result.stx_attributes_mask` members returned by
+:func:`os.statx`.  See the :manpage:`statx(2)` man page for more detail on the
+meaning of these constants.
+
+.. data:: STATX_ATTR_COMPRESSED
+          STATX_ATTR_IMMUTABLE
+          STATX_ATTR_APPEND
+          STATX_ATTR_NODUMP
+          STATX_ATTR_ENCRYPTED
+          STATX_ATTR_AUTOMOUNT
+          STATX_ATTR_MOUNT_ROOT
+          STATX_ATTR_VERITY
+          STATX_ATTR_DAX
+          STATX_ATTR_WRITE_ATOMIC
+
+   .. versionadded:: next

Include/internal/pycore_global_objects_fini_generated.h

@@ -590,6 +590,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(loop)
         STRUCT_FOR_ID(manual_reset)
         STRUCT_FOR_ID(mapping)
+        STRUCT_FOR_ID(mask)
         STRUCT_FOR_ID(match)
         STRUCT_FOR_ID(max_length)
         STRUCT_FOR_ID(maxdigits)
@@ -784,6 +785,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(sub_key)
         STRUCT_FOR_ID(subcalls)
         STRUCT_FOR_ID(symmetric_difference_update)
+        STRUCT_FOR_ID(sync)
         STRUCT_FOR_ID(tabsize)
         STRUCT_FOR_ID(tag)
         STRUCT_FOR_ID(target)

Include/internal/pycore_global_strings.h

@@ -131,6 +131,8 @@ def _add(str, fn):
     _add("HAVE_UNLINKAT",   "unlink")
     _add("HAVE_UNLINKAT",   "rmdir")
     _add("HAVE_UTIMENSAT",  "utime")
+    if _exists("statx"):
+        _set.add(statx)
     supports_dir_fd = _set
 
     _set = set()
@@ -152,6 +154,8 @@ def _add(str, fn):
     _add("HAVE_FPATHCONF",  "pathconf")
     if _exists("statvfs") and _exists("fstatvfs"): # mac os x10.3
         _add("HAVE_FSTATVFS", "statvfs")
+    if _exists("statx"):
+        _set.add(statx)
     supports_fd = _set
 
     _set = set()
@@ -190,6 +194,8 @@ def _add(str, fn):
     _add("HAVE_FSTATAT",    "stat")
     _add("HAVE_UTIMENSAT",  "utime")
     _add("MS_WINDOWS",      "stat")
+    if _exists("statx"):
+        _set.add(statx)
     supports_follow_symlinks = _set
 
     del _set

Include/internal/pycore_runtime_init_generated.h

@@ -200,6 +200,21 @@ def filemode(mode):
 FILE_ATTRIBUTE_VIRTUAL = 65536
 
 
+# Linux STATX_ATTR constants for interpreting os.statx()'s
+# "stx_attributes" and "stx_attributes_mask" members
+
+STATX_ATTR_COMPRESSED = 0x00000004
+STATX_ATTR_IMMUTABLE = 0x00000010
+STATX_ATTR_APPEND = 0x00000020
+STATX_ATTR_NODUMP = 0x00000040
+STATX_ATTR_ENCRYPTED = 0x00000800
+STATX_ATTR_AUTOMOUNT = 0x00001000
+STATX_ATTR_MOUNT_ROOT = 0x00002000
+STATX_ATTR_VERITY = 0x00100000
+STATX_ATTR_DAX = 0x00200000
+STATX_ATTR_WRITE_ATOMIC = 0x00400000
+
+
 # If available, use C implementation
 try:
     from _stat import *