Christian Franke via Cygwin wrote:
Ilya Basin via Cygwin wrote:
Hi.
I was trying to write an .img file to a VeraCrypt drive.
VeraCrypt doesn't create a virtual PhysicalDrive so tools like Rufus
don't see it.
I hoped that with cygwin I would be able to do that, but Cygwin only
creates /dev/sd?? nodes for PhysicalDrive partitions.
I tried `dd` with '\\.\X:', but it can't open for writing because it
treats it as a directory (reading succeeds).
$ dd count=1 if='\\.\E:' | xxd
1+0 records in
1+0 records out
512 bytes copied, 0.0213007 s, 24.0 kB/s
00000000: eb52 904e 5446 5320 2020 2000 0208 0000 .R.NTFS .....
...
$ dd if=/dev/null count=0 of='\\.\E:'
dd: failed to open '\\.\E:': Is a directory
Could reproduce this. The inconsistency between open for reading vs.
writing of '\\.\E:' is actually interesting. Subtle bug in Cygwin?
'\\.\X:' is mapped to NT path '\??\X:' internally. It is (mis-?)detected
as a directory. Open for write then fails intentionally:
int
fhandler_base::open_fs (int flags, mode_t mode)
{
/* Unfortunately NT allows to open directories for writing, but that's
disallowed according to SUSv3. */
if (pc.isdir () && (flags & O_ACCMODE) != O_RDONLY)
{
set_errno (EISDIR);
return 0;
}
...
}
stat() apparently returns garbage (X: is a mount point of a 1MiB
VeraCrypt file with FAT FS):
$ stat '\\.\X:'
File: \\.\X:
Size: 140720951294304 Blocks: 1 IO Block: 65536 regular file
Device: 0,195 Inode: 264012044753263394 Links: 0
Access: (0644/-rw-r--r--) Uid: ( 1000/ franke) Gid: ( 513/ none)
Access: 1601-01-01 01:22:04.,'-((0,00 +0053
Modify: 1601-01-01 01:22:04.+0/+'-,00 +0053
Change: 1601-01-01 00:53:29.'''''--00 +0053
Birth: -
$ ls -l /proc/sys/DosDevices/X:
lr--r--r-- 1 ... /proc/sys/DosDevices/X: ->
/proc/sys/Device/VeraCryptVolumeX
--
Regards,
Christian
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