Franz? Ping?
Thx, Corinna On Aug 2 16:59, Corinna Vinschen wrote: > Hi Franz, > > On Aug 2 16:26, Franz Sirl wrote: > > Am 2016-07-29 um 16:38 schrieb Corinna Vinschen: > > > On Jul 29 16:18, Corinna Vinschen wrote: > > > > In the first place it would be prudent to find out why the > > > > FileAllInformation info class fails on this drive. And in the second > > > > place it would be important to find out how to fix this. Potential > > > > checks: > > > > > > > > - Buffer alignment of the FILE_ALL_INFORMATION member in class > > > > path_conv_handle. > > > > > > > > - Buffer size of the FILE_ALL_INFORMATION member. For instance, > > > > does it work if the buffer is 1 byte bigger? Or perhaps if > > > > the buffer is NAME_MAX bigger? > > > > > > - There's also a chance (albeit minor) that the FileAllInformation call > > > actually worked and the weird status code is just wrong. After all, > > > returning from this call with STATUS_BUFFER_OVERFLOW is valid, too, > > > so I'd check for this as well here. > > > > Hi Corinna, > > > > no, the error code isn't influenced by alignment or size. For local drives > > and SMB shares the STATUS_BUFFER_OVERFLOW turns into STATUS_SUCCESS as soon > > as there is enough room for the share path in the > > FILE_NAME_INFORMATION.FileName flexible array member (actually, why isn't > > path_conv_handle.attribs._fai larger? performance? FileNameInformation > > usually not needed?). > > FileNameInformation is the full path to the file. It's not only not > needed, but for full long pathname support the buffer would have to > be sizeof (FILE_ALL_INFORMATION) + 32767 * sizeof (WCHAR), thus more > than 64K in size. > > FileAllInformation is designed so that you can ask for all information > except the filename by just ignoring the name buffer requirements. In > that case NtQueryInformationFile returns STATUS_BUFFER_OVERFLOW, which > can be ignored. > > > But for the NCP share the strange error code for > > FileAllInformation remains. Checking all the members of FileAllInformation > > one by one, it turned out that it's the FileInternalIformation member that > > fails. I've reported it as a bug to Novell. > > Cool. NtQueryInformationFile is supposed to just set all unsupported > members to 0, see the Remarks section of > https://msdn.microsoft.com/en-us/library/windows/hardware/ff567052(v=vs.85).aspx > > However, do we need a workaround? Kind of like this: > > diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc > index 970a0fe..d9ed357 100644 > --- a/winsup/cygwin/path.cc > +++ b/winsup/cygwin/path.cc > @@ -1307,6 +1307,19 @@ file_get_fai (HANDLE h, PFILE_ALL_INFORMATION pfai) > FileAllInformation); > if (status == STATUS_BUFFER_OVERFLOW) > status = STATUS_SUCCESS; > + /* Filesystems with broken FileAllInformation exist, too. See the thread > + starting with https://cygwin.com/ml/cygwin/2016-07/msg00350.html. */ > + else if (!NT_SUCCESS (status) && status != STATUS_ACCESS_DENIED) > + { > + memset (pfai, 0, sizeof *pfai); > + status = NtQueryInformationFile (h, &io, &pfai->BasicInformation, > + sizeof pfai->BasicInformation, > + FileBasicInformation); > + if (NT_SUCCESS (status)) > + status = NtQueryInformationFile (h, &io, &pfai->StandardInformation, > + sizeof pfai->StandardInformation, > + FileStandardInformation); > + } > return status; > } > > > > Nevertheless I believe the fallback to > > NtQueryDirectoryFile(FileIdBothDirectoryInformation) does not do what you > > want if the path is the root directory of a share. But that's not the cause > > of this problem. > > Yeah, as I wrote in my reply, the NtQueryDirectoryFile branch isn't > supposed to be hit in this scenario. It's solely for "access denied" > situations. > > Are you set up to build your own Cygwin DLL so you can test the above > patch locally? > > > Thanks, > Corinna > > -- > Corinna Vinschen Please, send mails regarding Cygwin to > Cygwin Maintainer cygwin AT cygwin DOT com > Red Hat -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat
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