For some time now, on and off, I've been looking at a problem that arose somewhere between the release of Cygwin.dll-1.5.18-2 and 1.5.19-4. I'm not actually a Cygwin user myself, but I support several such.
Our main fileserver is Solaris running TotalNet Advanced Server (TAS), which is `Samba-like, but not Samba' from the Windows PoV at least. In the time since the problem first arose, this hardware, the Solaris version it runs, and the TAS version on top of that, have changed without changing the nature of the problem at the Cygwin client end. All cygwin.dll releases since 1.5.18-1 produce 100% failure for any operation which (apparently) involves opendir/readdir operations, the most obvious of which is `ls'. Any attempt since 1.5.18-1 to run `ls' against any directory mounted from our TAS server results in ls: reading directory DIR: [ERROR] where `DIR' is the directory name mentioned and `[ERROR]' is some errno.h-like message, which was `Permission denied' under 1.5.19-4, but has become `Function not implemented' at some point since then. Following this via sources as far as possible, I note that the only way to get the above error message from `ls' is if the readdir() fails, and it seems that there are a fairly limited number of ways to get ENOSYS from fhandler_disk_file.cc. Without having the means (as far as I know) to draw out exactly what's happening, it seems to me that since 1.5.18-1, special arrangements have been made to handle directories on Samba-originated volumes that may have frustrated successful operation of Cygwin against similar Unix-originated volumes. For some time, we've worked on the theory that Cygwin is working properly and our TAS server is at fault, but having gone back to the code, I'm not so sure any more. My current feeling is that opendir() isn't conditioning the file-handler satisfactorily for subsequent readdir() on our remote volume, but I'm unsure exactly how. This particular problem is referred to directly in http://www.cygwin.com/ml/cygwin/2006-11/msg00568.html http://www.cygwin.com/ml/cygwin/2008-07/msg00534.html and it looks as if a very similar problem is seen by someone else in http://www.nabble.com/How-to-correctly-setup-passwd-and-group-to-access-mounted-drives--td17669276.html For a long time, we've been looking at it as a Windows/AD/domain-permissions-related problem, working on the theory that our Solaris server isn't quite behaving properly with respect to permissions, but when I look at the amount of work done on the opendir/readdir code between July 2005 and early 2006, especially given that some of it was Samba-related, I'm now wondering if it isn't a Cygwin coding issue. When I run `strace ls' (the TAS-mounted filesystem is H:\ in this case) I get the following (excerpt): ---------------------------------------------------------------- 578 129008 [main] ls 1624 normalize_posix_path: src . 302 129310 [main] ls 1624 cwdstuff::get: posix /cygdrive/h 369 129679 [main] ls 1624 cwdstuff::get: (/cygdrive/h) = cwdstuff::get (0x22C850, 260, 1, 0), errno 0 378 130057 [main] ls 1624 normalize_posix_path: /cygdrive/h/ = normalize_posix_path (.) 387 130444 [main] ls 1624 mount_info::conv_to_win32_path: conv_to_win32_path (/cygdrive/h) 364 130808 [main] ls 1624 mount_info::cygdrive_win32_path: src '/cygdrive/h', dst 'h:\' 397 131205 [main] ls 1624 set_flags: flags: binary (0x2) 349 131554 [main] ls 1624 mount_info::conv_to_win32_path: src_path /cygdrive/h, dst h:\, flags 0x2A, rc 0 6556 138110 [main] ls 1624 symlink_info::check: not a symlink 377 138487 [main] ls 1624 symlink_info::check: 0 = symlink.check (h:\, 0x22C510) (0x2A) 323 138810 [main] ls 1624 path_conv::check: this->path(h:\), has_acls(0) 377 139187 [main] ls 1624 build_fh_pc: fh 0x61169E00 5873 145060 [main] ls 1624 fhandler_disk_file::opendir: 0x692AB0 = opendir (/cygdrive/h) 890 145950 [main] ls 1624 geterrno_from_win_error: windows error 50 == errno 88 370 146320 [main] ls 1624 fhandler_disk_file::readdir: 0 = readdir (0x692AB0, 0x22C6D4) (.) 721 147041 [main] ls 1624 geterrno_from_win_error: windows error 50 == errno 88 416 147457 [main] ls 1624 normalize_posix_path: src /cygdrive/h/.. 345 147802 [main] ls 1624 normalize_posix_path: /cygdrive/ = normalize_posix_path (/cygdrive/h/..) 370 148172 [main] ls 1624 mount_info::conv_to_win32_path: conv_to_win32_path (/cygdrive) 385 148557 [main] ls 1624 set_flags: flags: binary (0x2) 365 148922 [main] ls 1624 mount_info::conv_to_win32_path: src_path /cygdrive, dst C:\cygwin\cygdrive, flags 0xA, rc 0 381 149303 [main] ls 1624 lstat64: entering 372 149675 [main] ls 1624 normalize_posix_path: src /cygdrive/h/.. 371 150046 [main] ls 1624 normalize_posix_path: /cygdrive/ = normalize_posix_path (/cygdrive/h/..) 378 150424 [main] ls 1624 mount_info::conv_to_win32_path: conv_to_win32_path(/cygdrive) 377 150801 [main] ls 1624 set_flags: flags: binary (0x2) 372 151173 [main] ls 1624 mount_info::conv_to_win32_path: src_path /cygdrive, dst C:\cygwin\cygdrive, flags 0xA, rc 0 477 151650 [main] ls 1624 build_fh_pc: fh 0x6116A008 283 151933 [main] ls 1624 stat_worker: (/cygdrive/h/.., 0x22C4E0, 1, 0x6116A008), file_attributes 17 369 152302 [main] ls 1624 stat_worker: 0 = (/cygdrive/h/.., 0x22C4E0) 376 152678 [main] ls 1624 fhandler_disk_file::readdir: 0 = readdir (0x692AB0, 0x22C6D4) (..) 747 153425 [main] ls 1624 geterrno_from_win_error: windows error 50 == errno 88 376 153801 [main] ls 1624 fhandler_disk_file::readdir: 88 = readdir (0x692AB0, 0x22C6D4) (***) 377 154178 [main] ls 1624 __set_errno: dirent* readdir(DIR*):160 val 88 -------------------------------------------------------------------------- and 88, ENOSYS, `Function not implemented' is what's reported to the user. It may still be the case, of course, that some Windows-permissions-related problem is at fault, but the fact remains that 1.5.18-1 still works, while nothing later than that does. The problem seems identical regardless of how the directory on the network-mounted volume is referred to. I'm happy to run further investigations: can anyone suggest a new angle to try? Thanks for any assistance, -- SAm. -- Academic Excellence at the Heart of Scotland. The University of Stirling is a charity registered in Scotland, number SC 011159. -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
