On Nov 3 10:55, Corinna Vinschen wrote:
> Hi Christian,
>
> On Oct 3 14:39, Christian Franke wrote:
> > Christian Franke wrote:
> > > This is a first attempt to partly emulate the Linux directory
> > > /dev/disk/by-id. Useful to make sure the correct device is accessed in
> > > conjunction with dd, ddrescue, fdisk, ....
> >
> > Attached is the second attempt.
> >
> >
> > > The additional '*-partN' links to partitions are not yet included.
> >
> > These are now included.
> >
> >
> > > This only works properly if Win32 path '\\.\PhysicalDriveN' is always
> > > trivially mapped to NT path '\Device\HarddiskN\Partition0'.
> > > IOCTL_STORAGE_QUERY_PROPERTY with a handle from NtOpenFile(.,
> > > READ_CONTROL,...) instead of CreateFile(., 0, ...) did not work with all
> > > drivers. With stornvme.sys, it fails with permission denied. Perhaps
> > > other permission bits are required for NtOpenFile(). Thanks for any info
> > > regarding this.
> >
> > According to NtQueryObject(., ObjectBasicInformation, ...), using
> > NtOpenFile(., MAXIMUM_ALLOWED, ...) without admin rights sets GrantedAccess
> > to 0x001200a0 (FILE_EXECUTE|FILE_READ_ATTRIBUTES|READ_CONTROL|SYNCHRONIZE).
> > For some unknown reason, NVMe drives behind stornvme.sys additionally
> > require SYNCHRONIZE to use IOCTL_STORAGE_QUERY_PROPERTY. Possibly a harmless
> > bug in the access check somewhere in the NVMe stack.
> >
> > The disk scanning from the first patch has been reworked based on code
> > borrowed from proc.cc:format_proc_partitions(). For the longer term, it may
> > make sense to provide one flexible scanning function for /dev/sdXN,
> > /proc/partitions and /proc/disk/by-id.
>
> I applied your patch locally (patch looks pretty well, btw) but found
> that /dev/disk/by-id is empty, even when running with admin rights.
>
> I ran this on Windows 11 and Windows 2K19 in a QEMU/KVM VM. A
> \Device\Harddisk0\Partition0 symlink pointing to \Device\Harddisk0\DR0
> exists in both cases. I straced it, and found the following debug
> output:
>
> 1015 1155432 [main] ls 361 stordesc_to_id_name: Harddisk0\Partition0:
> 'Red_Hat' 'VirtIO' '' (ignored)
>
> Is that really desired?
Thread 1 "ls" hit Breakpoint 2, stordesc_to_id_name (upath=0x7ffffc500,
ioctl_buf=0x10e0720 "(", name=...)
at /home/corinna/src/cygwin/vanilla/winsup/cygwin/fhandler/dev_disk.cc:44
44 const STORAGE_DEVICE_DESCRIPTOR *desc =
(gdb) n
47 int vendor_len = 0, product_len = 0, serial_len = 0;
(gdb)
48 if (desc->VendorIdOffset)
(gdb)
49 vendor_len = sanitize_id_string (ioctl_buf + desc->VendorIdOffset);
(gdb)
50 if (desc->ProductIdOffset)
(gdb)
51 product_len = sanitize_id_string (ioctl_buf +
desc->ProductIdOffset);
(gdb)
52 if (desc->SerialNumberOffset)
(gdb)
53 serial_len = sanitize_id_string (ioctl_buf +
desc->SerialNumberOffset);
(gdb)
55 bool valid = (4 <= vendor_len + product_len && 4 <= serial_len
(gdb) p vendor_len
$1 = 7
(gdb) p product_len
$2 = 6
(gdb) p serial_len
$3 = 0
(gdb) n
[New Thread 3944.0x1958]
56 && (20 + vendor_len + 1 + product_len + 1 + serial_len
+ 10)
(gdb) n
55 bool valid = (4 <= vendor_len + product_len && 4 <= serial_len
(gdb)
55 bool valid = (4 <= vendor_len + product_len && 4 <= serial_len
(gdb)
58 debug_printf ("%S: '%s' '%s' '%s'%s", upath,
(gdb) p valid
$4 = false
HTH,
Corinna
