From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: WSL symbolic links
Date: Thu, 26 Mar 2020 12:00:59 +0100 [thread overview]
Message-ID: <20200326110059.GG3261@calimero.vinschen.de> (raw)
In-Reply-To: <294944bd-757e-4bb8-6bcc-ceb8d9190ef9@towo.net>
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On Mar 26 10:00, Thomas Wolff wrote:
> A symbolic link created with WSL is neither interpreted in cygwin nor can it
> be deleted:
> > touch file
> > wsl ln -s file link
> > wsl ls -l link
> lrwxrwxrwx 1 towo towo 1 Mar 26 08:56 link -> file
> > ls -l link
> -rw-r----- 1 Unknown+User Unknown+Group 0 Mar 26 00:00 link
What kind of file are they in the real world? Reparse points? If so,
what content do they have? I attached a Q&D source from my vault
of old test apps to check on reparse point content. Please compile with
gcc -g ../src/rd-reparse.c -o rd-reparse -lntdll
It takes a single native NT path as parameter, kind of like this:
./rd-reparse '\??\C:\cygwin64\home\corinna\link'
Thanks,
Corinna
--
Corinna Vinschen
Cygwin Maintainer
[-- Attachment #1.2: rd-reparse.c --]
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#include <stdio.h>
#include <wchar.h>
#include <windows.h>
#include <winternl.h>
typedef struct {
DWORD ReparseTag;
WORD ReparseDataLength;
WORD Reserved;
union {
struct {
WORD SubstituteNameOffset;
WORD SubstituteNameLength;
WORD PrintNameOffset;
WORD PrintNameLength;
DWORD Flag;
WCHAR PathBuffer[1];
} SymbolicLinkReparseBuffer;
struct {
WORD SubstituteNameOffset;
WORD SubstituteNameLength;
WORD PrintNameOffset;
WORD PrintNameLength;
WCHAR PathBuffer[1];
} MountPointReparseBuffer;
struct {
BYTE DataBuffer[1];
} GenericReparseBuffer;
};
} MY_REPARSE_DATA_BUFFER, *MY_PREPARSE_DATA_BUFFER;
//ULONG WINAPI RtlCreateUnicodeStringFromAsciiz (PUNICODE_STRING, PCSTR);
int
main (int argc, char **argv)
{
HANDLE fh;
char buf[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
DWORD siz;
MY_PREPARSE_DATA_BUFFER rp;
char *pbuf;
char name[32768];
NTSTATUS status;
IO_STATUS_BLOCK io;
UNICODE_STRING fname;
OBJECT_ATTRIBUTES attr;
RtlCreateUnicodeStringFromAsciiz (&fname, argv[1]);
InitializeObjectAttributes(&attr, &fname, OBJ_CASE_INSENSITIVE, NULL, 0);
status = NtOpenFile (&fh, FILE_READ_EA | FILE_READ_ATTRIBUTES | SYNCHRONIZE,
&attr, &io,
FILE_SHARE_VALID_FLAGS,
FILE_SYNCHRONOUS_IO_NONALERT
| FILE_OPEN_FOR_BACKUP_INTENT
| FILE_OPEN_REPARSE_POINT);
if (!NT_SUCCESS (status))
{
fprintf (stderr, "NtOpenFile: %08X\n", status);
return 1;
}
status = NtFsControlFile (fh, NULL, NULL, NULL, &io,
FSCTL_GET_REPARSE_POINT, NULL, 0,
(LPVOID) buf, sizeof buf);
if (!NT_SUCCESS (status))
{
fprintf (stderr, "NtDeviceIoControlFile: %08lX\n", status);
CloseHandle (fh);
return 1;
}
rp = (MY_PREPARSE_DATA_BUFFER) buf;
printf ("ReparseTag: 0x%08x\n", rp->ReparseTag);
printf ("ReparseDataLength: %10d\n", rp->ReparseDataLength);
printf ("Reserved: %10d\n", rp->Reserved);
if (rp->ReparseTag == IO_REPARSE_TAG_SYMLINK
|| rp->ReparseTag == IO_REPARSE_TAG_SYMLINK)
{
printf ("SubstituteNameOffset: %10d\n",
rp->SymbolicLinkReparseBuffer.SubstituteNameOffset);
printf ("SubstituteNameLength: %10d\n",
rp->SymbolicLinkReparseBuffer.SubstituteNameLength);
printf ("PrintNameOffset: %10d\n",
rp->SymbolicLinkReparseBuffer.PrintNameOffset);
printf ("PrintNameLength: %10d\n",
rp->SymbolicLinkReparseBuffer.PrintNameLength);
if (rp->ReparseTag == IO_REPARSE_TAG_SYMLINK)
{
printf ("Flag: 0x%08x\n",
rp->SymbolicLinkReparseBuffer.Flag);
pbuf = (char *) rp->SymbolicLinkReparseBuffer.PathBuffer;
}
else
pbuf = (char *) rp->MountPointReparseBuffer.PathBuffer;
wcstombs (name,
(PWCHAR) (pbuf + rp->SymbolicLinkReparseBuffer.SubstituteNameOffset),
rp->SymbolicLinkReparseBuffer.SubstituteNameLength / 2);
name[rp->SymbolicLinkReparseBuffer.SubstituteNameLength / 2] = '\0';
printf("SubstituteName: %s\n", name);
wcstombs (name,
(PWCHAR) (pbuf + rp->SymbolicLinkReparseBuffer.PrintNameOffset),
rp->SymbolicLinkReparseBuffer.PrintNameLength / 2);
name[rp->SymbolicLinkReparseBuffer.PrintNameLength / 2] = '\0';
printf("PrintName: %s\n", name);
}
else
{
WORD i;
for (i = 0; i < rp->ReparseDataLength; ++i)
{
printf ("%02x ", rp->GenericReparseBuffer.DataBuffer[i]);
if ((i + 1) % 16 == 0)
putchar ('\n');
}
}
CloseHandle (fh);
return 0;
}
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next prev parent reply other threads:[~2020-03-26 11:01 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-26 9:00 Thomas Wolff
2020-03-26 11:00 ` Corinna Vinschen [this message]
2020-03-26 16:15 ` Thomas Wolff
2020-03-26 19:12 ` Brian Inglis
2020-03-26 19:56 ` Corinna Vinschen
2020-03-26 23:52 ` Thomas Wolff
2020-03-27 5:46 ` ASSI
2020-03-27 11:21 ` Corinna Vinschen
2020-03-27 12:24 ` Thomas Wolff
2020-03-27 13:01 ` Corinna Vinschen
2020-03-27 14:43 ` Thomas Wolff
2020-03-26 20:05 ` Corinna Vinschen
2020-03-27 17:58 ` Brian Inglis
2020-03-27 18:53 ` Corinna Vinschen
2020-03-28 3:32 ` Brian Inglis
2020-03-28 10:31 ` Henry S. Thompson
2020-03-28 11:30 ` Thomas Wolff
2020-03-28 11:59 ` Andrey Repin
2020-03-28 20:45 ` Brian Inglis
2020-03-29 11:52 ` Andrey Repin
2020-03-30 8:46 ` Corinna Vinschen
2020-04-04 14:32 ` Denis Excoffier
2020-04-05 15:22 ` Corinna Vinschen
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