From 855ea3fddd01211d31bd05990ab6d55347f743c1 Mon Sep 17 00:00:00 2001 From: Corinna Vinschen Date: Sat, 24 Dec 2011 13:11:34 +0000 Subject: [PATCH] * path.cc (struct symlink_info): Add bool argument to declaration of check_reparse_point. (symlink_info::check_reparse_point): Add bool argument to indicate remote drive. Handle STATUS_PENDING. Don't evaluate junctions on remote drives. Fix comments. (symlink_info::check): Drop check for is_remote_drive and associated comment here. Add fs.is_remote_drive as second parameter to check_reparse_point call. --- winsup/cygwin/ChangeLog | 11 ++++++++++ winsup/cygwin/path.cc | 46 ++++++++++++++++++++++++++--------------- 2 files changed, 40 insertions(+), 17 deletions(-) diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog index 1f63e4186..2686bda5b 100644 --- a/winsup/cygwin/ChangeLog +++ b/winsup/cygwin/ChangeLog @@ -1,3 +1,14 @@ +2011-12-24 Corinna Vinschen + + * path.cc (struct symlink_info): Add bool argument to declaration of + check_reparse_point. + (symlink_info::check_reparse_point): Add bool argument to indicate + remote drive. Handle STATUS_PENDING. Don't evaluate junctions on + remote drives. Fix comments. + (symlink_info::check): Drop check for is_remote_drive and associated + comment here. Add fs.is_remote_drive as second parameter to + check_reparse_point call. + 2011-12-23 Corinna Vinschen * pinfo.cc (pinfo_basic::pinfo_basic): Fix formatting. Set uid and gid diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc index 36a069c89..0b8539065 100644 --- a/winsup/cygwin/path.cc +++ b/winsup/cygwin/path.cc @@ -102,7 +102,7 @@ struct symlink_info bool parse_device (const char *); int check_sysfile (HANDLE h); int check_shortcut (HANDLE h); - int check_reparse_point (HANDLE h); + int check_reparse_point (HANDLE h, bool remote); int check_nfs_symlink (HANDLE h); int posixify (char *srcbuf); bool set_error (int); @@ -1958,7 +1958,7 @@ symlink_info::check_sysfile (HANDLE h) } int -symlink_info::check_reparse_point (HANDLE h) +symlink_info::check_reparse_point (HANDLE h, bool remote) { tmp_pathbuf tp; NTSTATUS status; @@ -1967,9 +1967,20 @@ symlink_info::check_reparse_point (HANDLE h) UNICODE_STRING subst; char srcbuf[SYMLINK_MAX + 7]; - status = NtFsControlFile (h, NULL, NULL, NULL, &io, FSCTL_GET_REPARSE_POINT, - NULL, 0, (LPVOID) rp, + /* On remote drives or under heavy load, NtFsControlFile can return with + STATUS_PENDING. If so, instead of creating an event object, just set + io.Status to an invalid value and perform a minimal wait until io.Status + changed. */ + memset (&io, 0xff, sizeof io); + status = NtFsControlFile (h, NULL, NULL, NULL, &io, + FSCTL_GET_REPARSE_POINT, NULL, 0, (LPVOID) rp, MAXIMUM_REPARSE_DATA_BUFFER_SIZE); + if (status == STATUS_PENDING) + { + while (io.Status == (NTSTATUS) 0xffffffff) + Sleep (1L); + status = io.Status; + } if (!NT_SUCCESS (status)) { debug_printf ("NtFsControlFile(FSCTL_GET_REPARSE_POINT) failed, %p", @@ -1978,12 +1989,21 @@ symlink_info::check_reparse_point (HANDLE h) return 0; } if (rp->ReparseTag == IO_REPARSE_TAG_SYMLINK) + /* Windows evaluates native symlink literally. If a remote symlink points + to, say, C:\foo, it will be handled as if the target is the local file + C:\foo. That comes in handy since that's how symlinks are treated under + POSIX as well. */ RtlInitCountedUnicodeString (&subst, (WCHAR *)((char *)rp->SymbolicLinkReparseBuffer.PathBuffer + rp->SymbolicLinkReparseBuffer.SubstituteNameOffset), rp->SymbolicLinkReparseBuffer.SubstituteNameLength); - else if (rp->ReparseTag == IO_REPARSE_TAG_MOUNT_POINT) + else if (!remote && rp->ReparseTag == IO_REPARSE_TAG_MOUNT_POINT) { + /* Don't handle junctions on remote filesystems as symlinks. This type + of reparse point is handled transparently by the OS so that the + target of the junction is the remote directory it is supposed to + point to. If we handle it as symlink, it will be mistreated as + pointing to a dir on the local system. */ RtlInitCountedUnicodeString (&subst, (WCHAR *)((char *)rp->MountPointReparseBuffer.PathBuffer + rp->MountPointReparseBuffer.SubstituteNameOffset), @@ -1998,10 +2018,9 @@ symlink_info::check_reparse_point (HANDLE h) } else { - /* Maybe it's a reparse point, but it's certainly not one we - recognize. Drop the REPARSE file attribute so we don't even - try to use the flag for some special handling. It's just some - arbitrary file or directory for us. */ + /* Maybe it's a reparse point, but it's certainly not one we recognize. + Drop REPARSE attribute so we don't try to use the flag accidentally. + It's just some arbitrary file or directory for us. */ fileattr &= ~FILE_ATTRIBUTE_REPARSE_POINT; return 0; } @@ -2597,14 +2616,7 @@ restart: with SYSTEM and HIDDEN flags set. */ if ((fileattr & FILE_ATTRIBUTE_REPARSE_POINT)) { - /* Don't check reparse points on remote filesystems. A reparse point - pointing to another file on the remote system will be mistreated - as pointing to a local file on the local system. This breaks the - way reparse points are transparently handled on remote systems. */ - if (fs.is_remote_drive()) - res = 0; - else - res = check_reparse_point (h); + res = check_reparse_point (h, fs.is_remote_drive ()); if (res == -1) { /* Volume mount point. The filesystem information for the top