Eryk Sun added the comment:
As a workaround you can open a file descriptor via os.open:
>>> import os
>>> fd = os.open(r'\\.\PhysicalDrive0', os.O_RDONLY | os.O_BINARY)
>>> os.read(fd, 512)[:8]
b'3\xc0\x8e\xd0\xbc\x00|\x8e'
> _Py_fstat result not used on windows in this place.
While it's pretty much useless, it is possible to open a CRT file descriptor
for a directory handle:
>>> h = _winapi.CreateFile('C:\\', 0x80000000, 3, 0, 3, 0x02000000, 0)
>>> fd = msvcrt.open_osfhandle(h, os.O_RDONLY)
>>> open(fd)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
IsADirectoryError: [Errno 21] Is a directory: 3
So calling _Py_fstat shouldn't be skipped on Windows.
The issue is that a raw disk device doesn't support querying information
(IRP_MJ_QUERY_INFORMATION), as shown in this local kernel debugging session:
lkd> !object \GLOBAL??\PhysicalDrive0
[...]
Target String is '\Device\Harddisk0\DR0'
lkd> !object \Device\Harddisk0\DR0
Object: ffffe001c4fa4500 Type: (ffffe001c3d7bd30) Device
[...]
lkd> !devobj ffffe001c4fa4500
Device object (ffffe001c4fa4500) is for:
DR0 \Driver\disk DriverObject ffffe001c4fa3310
[...]
lkd> !drvobj \Driver\disk 2
[...]
Dispatch routines:
[...]
[05] IRP_MJ_QUERY_INFORMATION fffff8037251a06c nt!IopInvalidDeviceRequest
[06] IRP_MJ_SET_INFORMATION fffff8037251a06c nt!IopInvalidDeviceRequest
[...]
Specifically WinAPI GetFileInformationByHandle calls the system function
NtQueryInformationFile. The system call makes an IRP_MJ_QUERY_INFORMATION I/O
request of the driver, which for a raw disk device is handled by
IopInvalidDeviceRequest. This fails the request with
STATUS_INVALID_DEVICE_REQUEST (0xC0000010), which translates to WinAPI
ERROR_INVALID_FUNCTION (0x0001).
Possibly in the case of ERROR_INVALID_FUNCTION, FileIO can just call
PyErr_Clear and skip the code that uses fdfstat.
----------
nosy: +eryksun
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue25639>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
