Difference to Linux: We can't create files which don't show up
in the filesystem due to OS restrictions. As a kludge, make a
(half-hearted) attempt to hide the file in the filesystem.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Also updates the fhandler_*::ftruncate implementations to adhere to the same
semantics. The error handling semantics of those syscalls that use
fhandler_*::ftruncate are moved to the implementations of those syscalls (
in particular ftruncate() and friends still set errno and return -1 on error
but that logic is handled in the syscall implementation).
Under some not quite clear conditions, NFS fails to use its
unlink workaround to rename a file to ".nfsXYZ". The problem has been
reproduced with the GAWK testext.awk testcase. To workaround this in
Cygwin, we now call try_to_bin on NFS, too. For some reason NFS doesn't
fail to rename the .cygXYZ file to .nfsXYZ after this Cygwin rename.
Fix comment in unlink_nt accordingly.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The "final trick" code in try_to_bin accidentally never worked on
remote drives because it relies on rootdir. Which isn't set for
remote unlinks. The code now creates a full path for remote files.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
The try_to_bin function isn't called for netapp FSes anyway, so testing
for this FS type in the function is moot.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
If newfile already exists and is in use, trying to overwrite it with
NtSetInformationFile(FileRenameInformation) fails exactly as if we
don't have the permissions to delete it. Unfortunately the return code
is the same STATUS_ACCESS_DENIED, so we have no way to distinguish
these cases. What we do here so far is to start a transaction to delete
newfile. If this open fails with a transactional error we stop the
transaction and retry opening the file without transaction.
But, here's the problem: If newfile is in use, NtOpenFile(oldfile)
naturally does NOT fail with a transactional error. Rather, the
subsequent call to unlink_nt(newfile) does, because there's another
handle open to newfile outside a transaction. However, the code does
not check if unlink_nt fails with a transactional error and so fails
to retry without transaction.
This patch recifies the problem and checks unlink_nt's status as well.
Refactor code to get rid of goto into another code block.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Long-standing problem in one of the corner cases of rename(2):
If we rename a directory a check is performed to see if newpath is
identical to oldpath or a subdir of oldpath. This check is
(accidentally? no hints anywhere in ChangeLogs or code) performed
case-insensitive for as long as we use Unicode paths and NT functions.
This leads to the problems described in
https://cygwin.com/ml/cygwin/2016-09/msg00264.html
Change this to be conditional case-sensitive as all other checks but
let's take this with a grain of salt. There may be corner-cases in
this corner-case which require to chek parts of the path always
case-insensitive. Off the top of my head I can't construct such a
case but that's no proof they don't exist :}
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Revamp device parsing code. Introducing support for more partitions
into the shilka-generated parser has the unfortunate side-effect of
raising the size of the DLL by almost 2 Megs. Therefore we split out
the handling for /dev/sdXY devices into a tiny bit of hand-written
code.
While at it, remove some unused cruft from devices.* and generally
clean up the device class to provide access methods instead of direct
access to members.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Bump GPLv2+ to GPLv3+ for some files, clarify BSD 2-clause.
Everything else stays under GPLv3+.
New Linking Exception exempts resulting executables from LGPLv3 section 4.
Add CONTRIBUTORS file to keep track of licensing.
Remove 'Copyright Red Hat Inc' comments.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
- New, unified implementation of POSIX permission and ACL handling. The
new ACLs now store the POSIX ACL MASK/CLASS_OBJ permission mask, and
they allow to inherit the S_ISGID bit. ACL inheritance now really
works as desired, in a limited, but theoretically equivalent fashion
even for non-Cygwin processes.
To accommodate Windows default ACLs, the new code ignores SYSTEM and
Administrators group permissions when computing the MASK/CLASS_OBJ
permission mask on old ACLs, and it doesn't deny access to SYSTEM and
Administrators group based on the value of MASK/CLASS_OBJ when
creating the new ACLs.
The new code now handles the S_ISGID bit on directories as on Linux:
Setting S_ISGID on a directory causes new files and subdirs created
within to inherit its group, rather than the primary group of the user
who created the file. This only works for files and directories
created by Cygwin processes.
2015-05-29 Corinna Vinschen <corinna@vinschen.de>
Reapply POSIX ACL changes.
* utils.xml (setfacl): Show new option output.
(getfacl): Show new option output.
* sec_acl.cc (get_posix_access): Check for Cygwin "standard" ACL.
Apply umask, if so. Align comments.
* security.cc (set_created_file_access): Fix permission masking by
incoming requested file mode.
* sec_acl.cc (set_posix_access): Apply mask only in terms of execute bit
for SYSTEM and Admins group.
* sec_acl.cc (set_posix_access): Don't create DENY ACEs for USER and
GROUP entries if they are the same as USER_OBJ or GROUP_OBJ.
* fhandler.h (fhandler_pty_slave::facl): Add prototype.
* fhandler_tty.cc (fhandler_pty_slave::facl): New method.
(fhandler_pty_slave::fchown): Fix uid/gid handling.
* sec_acl.cc (set_posix_access): Drop superfluous class_idx variable.
Simplify and move around code in a few places. To improve ACL
readability, add r/w permissions to Admins ACE appended to pty ACL.
Add comment to explain Windows ACE Mask filtering being in the way of
creating a real CLASS_OBJ.
(get_posix_access): Fake CLASS_OBJ for ptys. Explain why.
* security.cc (get_object_attribute): Add S_IFCHR flag to attributes
when calling get_posix_access.
* sec_acl.cc (set_posix_access): Move merging group perms into owner
perms in case of owner == group after mask has been computed. Take
mask into account when doing so to avoid unnecessary ACCESS_DENIED_ACE.
* sec_acl.cc (get_posix_access): Only set saw_group_obj flag if we saw
the ACCESS_ALLOWED_ACE.
* fhandler_disk_file.cc (fhandler_disk_file::fchmod): Deliberatly
set GROUP_OBJ and CLASS_OBJ perms to new group perms. Add comment
to explain why.
* security.cc (set_created_file_access): Ditto.
* sec_acl.cc (set_posix_access): Replace previous patch. Return
EINVAL if uid and/or guid is invalid and not backed by an actual
Windows account.
* sec_acl.cc (set_posix_access): Workaround owner/group SIDs being NULL.
* sec_acl.cc (set_posix_access): Handle files with owner == group.
Rephrase switch statement checking against unfiltered a_type value.
(get_posix_access): Handle files with owner == group.
* sec_acl.cc (get_posix_access): Don't use GROUP_OBJ access to fix up
CLASS_OBJ mask on old-style ACLs. Fix a comment.
* sec_acl.cc (set_posix_access): Always make sure Admins have
WRITE_DAC and WRITE_OWNER permissions.
* security.h (create_object_sd_from_attribute): Drop handle parameter
from prototype.
* security.cc (create_object_sd_from_attribute): Drop handle parameter.
Just create the standard POSIXy security descriptor.
(set_object_attribute): Accommodate dropped paramter in call to
create_object_sd_from_attribute.
* fhandler_tty.cc: Ditto, throughout.
* fhandler_disk_file.cc (fhandler_disk_file::fchmod): Fix typo in
mask computation.
* fhandler.cc (fhandler_base::open_with_arch): Call open with mode
not umasked.
(fhandler_base::open): Explicitely umask mode on NFS here. Call new
set_created_file_access rather than set_file_attribute.
* fhandler_disk_file.cc (fhandler_disk_file::fchmod): Reimplement
setting permissions on filesystems supporting ACLs using the new
set_posix_access call.
(fhandler_disk_file::fchown): Ditto.
(fhandler_disk_file::mkdir): Call new set_created_file_access rather
than set_file_attribute.
* fhandler_socket.cc (fhandler_socket::bind): Don't umask here. Add
WRITE_OWNER access to allow writing group in case of SGID bit set.
Call new set_created_file_access rather than set_file_attribute.
* path.cc (symlink_worker): Call new set_created_file_access rather
than set_file_attribute.
* sec_acl.cc (searchace): Un-staticize.
(set_posix_access): New, complementary functionality to
get_posix_access.
(setacl): Implement in terms of get_posix_access/set_posix_access.
(get_posix_access): Add handling for just created files requiring
their first Cygwin ACL. Fix new_style recognition. Handle SGID
bit. For old-style ACLs, ignore SYSTEM and Administrators when
computing the {DEF_}CLASS_OBJ perms.
* security.cc (get_file_sd): Revamp comment. Change and (hopefully)
speed up inheritance processing for just created files.
(alloc_sd): Remove.
(set_security_attribute): Call set_posix_access instead of alloc_sd.
(get_object_attribute): Fix return value.
(create_object_sd_from_attribute): Call set_posix_access instead of
alloc_sd.
(set_file_attribute): Remove.
(set_created_file_access): New function implemented in terms of
get_posix_access/set_posix_access.
* security.h (set_file_attribute): Remove prototype.
(set_created_file_access): Add prototype.
(searchace): Ditto.
(set_posix_access): Ditto.
* syscalls.cc (open): Call open_with_arch with mode not umasked.
* sec_acl.cc: Change preceeding comment explaining new-style ACLs.
Describe how to generate deny ACEs in more detail. Accommodate the
fact that a NULL deny ACE is used for {DEF_}CLASS_OBJ, rather than
a special Cygwin ACE. Improve further comments.
(CYG_ACE_NEW_STYLE): Define.
(get_posix_access): Change from Cygwin ACE to NULL deny ACE. Fix
CLASS_OBJ handling to generate CLASS_OBJ and DEF_CLASS_OBJ from a single
NULL deny ACE if the inheritance flags say so.
* sec_helper.cc (well_known_cygwin_sid): Remove.
* security.h (well_known_cygwin_sid): Drop declaration.
* sec_acl.cc (CYG_ACE_ISBITS_TO_WIN): Fix typo.
(get_posix_access): Rename index variable from i to idx. Define only
once at top level.
* security.cc (add_access_allowed_ace): Drop unused parameter "offset".
Accommodate throughout.
(add_access_denied_ace): Ditto.
* sec_acl.cc: Accommodate above change throughout.
* security.h (add_access_allowed_ace): Adjust prototype to above change.
(add_access_denied_ace): Ditto.
* sec_acl.cc (get_posix_access): Handle multiple ACEs for the
owner and primary group of the file. Handle the default primary
group ACE as DEF_GROUP_OBJ entry if the directory has the S_ISGID bit
set. Add comments. Minor code rearrangements.
Preliminary read side implementation of new permission handling.
* acl.h (MAX_ACL_ENTRIES): Raise to 2730. Add comment to explain.
* sec_acl.cc: Add leading comment to explain new ACL style.
Add definitions and macros to use for bits in new Cygwin ACL.
(DENY_RWX): New mask value for all temporary deny bits.
(getace): Add bool parameter to decide when leaving all bits intact,
rather than filtering them per the already set bits.
(get_posix_access): New function, taking over functionality to read
POSIX ACL from SECURITY_DESCRIPTOR.
(getacl): Just call get_posix_access.
* sec_helper.cc (well_known_cygwin_sid): Define.
* security.cc (get_attribute_from_acl): Remove.
(get_info_from_sd): Remove.
(get_reg_sd): Call get_posix_access instead of get_info_from_sd.
(get_file_attribute): Ditto.
(get_object_attribute): Ditto.
* security.h (well_known_cygwin_sid): Declare.
(get_posix_access): Add prototype.
* Throughout, use simpler ACE macros from Windows' accctrl.h.
* getfacl.c (main): Special-case SYSTEM and Admins group. Add comments.
* setfacl.c: Align more to Linux tool.
(delacl): New function to delete acl entries only.
(modacl): Drop delete functionality. Add handling of recomputing the
mask and default mask values.
(delallacl): Rename from delacl.
(setfacl): Call delacl in Delete case. Call delallacl in DeleteAll
and DeleteDef case.
(usage): Accommodate new options. Rearrange and rephrase slightly.
(longopts): Emit 'x' in --delete case. Add --no-mask and --mask
options.
(opts): Add -x and -n options.
(main): Handle -d and -x the same. Handle -n and --mask options.
Drop handling for -r option.
* getfacl.c (usage): Align more closely to Linux version. Add new
options -c, -e, -E. Change formatting to accommodate longer options.
(longopts): Rename --noname to --numeric. Keep --noname for backward
compatibility. Add --omit-header, --all-effective and --no-effective
options.
(opts): Add -c, -e and -E option.
(main): Handle new -c, -e, and -E options.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* path.cc (path_conv::set_nt_native_path): New function.
* path.h (path_conv::set_nt_native_path): Add prototype.
* syscall.cc (try_to_bin): Handle moving files to the recycler
accessed via a local virtual drive (subst). Fix a problem renaming
the file to the unique replacement name on Samba. Align comment.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
suffix and make private. Rename normalized_path to posix_path and
make privtae. Accommodate name changes throughout in path_conv
methods.
(path_conv::known_suffix): New method. Use throughout instead of
accessing suffix directly.
(path_conv::get_win32): Constify.
(path_conv::get_posix): New method to read posix_path. Use throughout
instead of accessing normalized_path directly.
(path_conv::set_posix): Rename from set_normalized_path. Accommodate
name change throughout.
* spawn.cc (find_exec): Return POSIX path, not Win32 path.
(LoadUserProfileW): Import.
* registry.cc (get_registry_hive_path): Move to sec_auth.cc.
(load_registry_hive): Remove.
* registry.h (get_registry_hive_path): Drop declaration.
(load_registry_hive): Ditto.
* sec_auth.cc (get_user_profile_directory): Moved from registry.cc and
renamed. Take third parameter with buffer length.
(load_user_profile): New function taking over for load_registry_hive.
Use official functions to load profile. If profile is missing, create
it on Vista and later.
* security.h (get_user_profile_directory): Declare.
(load_user_profile): Declare.
* syscalls.cc (seteuid32): Replace call to load_registry_hive with call
to load_user_profile.
* uinfo.cc (cygheap_user::env_userprofile): Replace call to
get_registry_hive_path with call to get_user_profile_directory.
POBJECT_ATTRIBUTES. Take OBJECT_ATTRIBUTES reference as argument, not
pointer.
* fhandler_disk_file.cc: Throughout accommodate above change.
* syscalls.cc: Ditto.
* ntea.cc (read_ea): Don't set hdl to NULL if it's already NULL. Set
attr with pc.init_reopen_attr before trying to reopen file.
(write_ea): Ditto.
* security.cc (get_file_sd): Use pc.init_reopen_attr rather than
pc.get_object_attr when trying to reopen file.
(set_file_sd): Ditto.
handler.
* cygtls.cc (_cygtls::remove): Accommodate the fact that pathbufs
has been moved from _local_storage to _cygtls.
* cygtls.h (class tls_pathbuf): Add comment to hint to gendef usage
of counters. Change type of counters to uint32_t for clarity.
Remove _cygtls as friend class.
(struct _local_storage): Move pathbufs from here...
(struct _cygtls): ...to here, allowing to access it from _sigbe.
(class san): Only define on 32 bit. Remove errno, _c_cnt and _w_cnt
members.
(san::setup): Drop parameter. Don't initialize removed members.
(san::leave): Don't set removed members.
(class myfault): Only define on 32 bit.
(myfault::faulted): Only keep implementation not taking any parameter.
Drop argument in call to sebastian.setup.
(__try/__leave/__except/__endtry): Implement to support real SEH. For
now stick to SJLJ on 32 bit.
* dcrt0.cc (dll_crt0_0): Drop 64 bit call to
exception::install_myfault_handler.
* exception.h (exception_handler): Define with EXCEPTION_DISPOSITION
as return type.
(PDISPATCHER_CONTEXT): Define as void * on 32 bit. Define as pointer
to _DISPATCHER_CONTEXT on 64 bit.
(class exception): Define separately for 32 and 64 bit.
(exception::myfault): Add handler for myfault SEH handling on 64 bit.
(exception::exception): Fix mangled method name to account for change
in type of last parameter.
(exception::install_myfault_handler): Remove.
* exceptions.cc (exception::myfault_handle): Remove.
(exception::myfault): New SEH handler for 64 bit.
* gendef (_sigbe): Set tls_pathbuf counters to 0 explicitely when
returning to the caller.
* ntdll.h: Move a comment to a better place.
(struct _SCOPE_TABLE): Define on 64 bit.
* thread.cc (verifyable_object_isvalid): Remove gcc 4.7 workaround.
* tls_pbuf.cc (tls_pbuf): Fix to accommodate new place of pathbufs.
(tls_pathbuf::destroy): Change type of loop variables to uint32_t.
* tls_pbuf.h (class tmp_pathbuf): Change type of buffer counters to
uint32_t. Accommodate new place of pathbufs.
* tlsoffsets.h: Regenerate.
* tlsoffsets64.h: Regenerate.
instead of unsigned throughout. Change functions to static inline and
always inline.
(cpuid): Add parameter to set ecx, allowing to request extended CPUID
info.
* fhandler_proc.cc (format_proc_cpuinfo): Use uint32_t instead of
unsigned throughout. Add fake decimal places to MHz info. Handle more
feature flags.
* fhandler_random.cc (fhandler_dev_random::write): Allow up to 4K
input to add entropy.
* syscalls.cc: Drop including cpuid.h.
/etc/nsswitch.conf file to configure it.
* Makefile.in (DLL_OFILES): Add ldap.o.
* autoload.cc: Import ldap functions from wldap32.dll.
(DsEnumerateDomainTrustsW): Import.
(NetGroupGetInfo): Import.
* cygheap.h (class cygheap_domain_info): New class to keep global
domain info.
(class cygheap_pwdgrp): New class to keep passwd/group caches and
configuration info from /etc/nssswitch.conf.
(struct init_cygheap): Add cygheap_domain_info member "dom" and
cygheap_pwdgrp member "pg".
* cygtls.h (struct _local_storage): Remove unused member "res".
Rearrange slightly, Add members pwbuf and grbuf to implement non-caching
passwd/group fetching from SAM/AD. Make pw_pos and pw_pos unsigned.
* fhandler_disk_file.cc (fhandler_base::fstat_by_nfs_ea): Add RFC 2307
uid/gid mapping.
* fhandler_process.cc: Drop including pwdgrp.h.
* fhandler_procsysvipc.cc: Ditto.
* fhandler_registry.cc (fhandler_registry::fstat): Set key uid/gid
to ILLEGAL_UID/ILLEGAL_GID rather than UNKNOWN_UID/UNKNOWN_GID.
* grp.cc (group_buf): Drop.
(gr): Drop.
(pwdgrp::parse_group): Fill pg_grp.
(pwdgrp::read_group): Remove.
(pwdgrp::init_grp): New method.
(pwdgrp::prep_tls_grbuf): New method.
(pwdgrp::find_group): New methods.
(internal_getgrsid): Convert to call new pwdgrp methods.
(internal_getgrnam): Ditto.
(internal_getgrgid): Ditto.
(getgrgid_r): Drop 2nd parameter from internal_getgrgid call.
(getgrgid32): Ditto.
(getgrnam_r): Ditto for internal_getgrnam.
(getgrnam32): Ditto.
(getgrent32): Convert to call new pwdgrp methods.
(internal_getgrent): Remove.
(internal_getgroups): Simplify, especially drop calls to
internal_getgrent.
* ldap.cc: New file implementing cyg_ldap class for LDAP access to AD
and RFC 2307 server.
* ldap.h: New header, declaring cyg_ldap class.
* passwd.cc (passwd_buf): Drop.
(pr): Drop.
(pwdgrp::parse_passwd): Fill pg_pwd.
(pwdgrp::read_passwd): Remove.
(pwdgrp::init_pwd): New method.
(pwdgrp::prep_tls_pwbuf): New method.
(find_user): New methods.
(internal_getpwsid): Convert to call new pwdgrp methods.
(internal_getpwnam): Ditto.
(internal_getpwuid): Ditto.
(getpwuid32): Drop 2nd parameter from internal_getpwuid call.
(getpwuid_r): Ditto.
(getpwnam): Ditto for internal_getpwnam.
(getpwnam_r): Ditto.
(getpwent): Convert to call new pwdgrp methods.
* path.cc (class etc): Remove all methods.
* path.h (class etc): Drop.
* pinfo.cc (pinfo_basic::pinfo_basic): Set gid to ILLEGAL_GID rather
than UNKNOWN_GID.
(pinfo_init): Ditto.
* pwdgrp.h (internal_getpwnam): Drop 2nd parameter from declaration.
(internal_getpwuid): Ditto.
(internal_getgrgid): Ditto.
(internal_getgrnam): Ditto.
(internal_getgrent): Drop declaration.
(enum fetch_user_arg_type_t): New type.
(struct fetch_user_arg_t): New type.
(struct pg_pwd): New type.
(struct pg_grp): New type.
(class pwdgrp): Rework to provide functions for file and db requests
and caching.
(class ugid_cache_t): New class to provide RFC 2307 uid map caching.
(ugid_cache): Declare.
* sec_acl.cc: Drop including pwdgrp.h.
* sec_auth.cc: Drop including dsgetdc.h and pwdgrp.h.
(get_logon_server): Convert third parameter to ULONG flags argument
to allow arbitrary flags values in DsGetDcNameW call and change calls
to this function throughout. Use cached account domain name rather
than calling GetComputerNameW.
(get_unix_group_sidlist): Remove.
(get_server_groups): Drop call to get_unix_group_sidlist.
(verify_token): Rework token group check without calling
internal_getgrent.
* sec_helper.cc (cygpsid::pstring): New methods, like string() but
return pointer to end of string.
(cygsid::getfromstr): Add wide character implementation.
(get_sids_info): Add RFC 2307 uid/gid mapping for Samba shares.
* security.cc: Drop including pwdgrp.h.
* security.h (DEFAULT_UID): Remove.
(UNKNOWN_UID): Remove.
(UNKNOWN_GID): Remove.
(uinfo_init): Move here from winsup.h.
(ILLEGAL_UID): Ditto.
(ILLEGAL_GID): Ditto.
(UNIX_POSIX_OFFSET): Define. Add lengthy comment.
(UNIX_POSIX_MASK): Ditto.
(MAP_UNIX_TO_CYGWIN_ID): Ditto.
(ILLEGAL_UID16): Move here from winsup.h.
(ILLEGAL_GID16): Ditto.
(uid16touid32): Ditto.
(gid16togid32): Ditto.
(sid_id_auth): New convenience macro for SID component access.
(sid_sub_auth_count): Ditto.
(sid_sub_auth): Ditto.
(sid_sub_auth_rid): Ditto.
(cygpsid::pstring): Declare.
(cygsid::getfromstr): Declare wide character variant.
(cygsid::operator=): Ditto.
(cygsid::operator*=): Ditto.
(get_logon_server): Change declaration according to source code.
* setlsapwd.cc (setlsapwd): Drop 2nd parameter from internal_getpwnam
call.
* shared.cc (memory_init): Call cygheap->pg.init in first process.
* syscalls.cc: Drop including pwdgrp.h.
* tlsoffsets.h: Regenerate.
* tlsoffsets64.h: Ditto.
* uinfo.cc (internal_getlogin): Drop gratuitious internal_getpwuid
call. Fix debug output. Overwrite user gid in border case of a
missing passwd file while a group file exists.
(pwdgrp::add_line): Allocate memory on cygheap.
(pwdgrp::load): Remove.
(ugid_cache): Define.
(cygheap_pwdgrp::init): New method.
(cygheap_pwdgrp::nss_init_line): New method.
(cygheap_pwdgrp::_nss_init): New method.
(cygheap_domain_info::init): New method.
(logon_sid): Define.
(get_logon_sid): New function.
(pwdgrp::add_account_post_fetch): New method.
(pwdgrp::add_account_from_file): New methods.
(pwdgrp::add_account_from_windows): New methods.
(pwdgrp::check_file): New method.
(pwdgrp::fetch_account_from_line): New method.
(pwdgrp::fetch_account_from_file): New method.
(pwdgrp::fetch_account_from_windows): New method.
* winsup.h: Move aforementioned macros and declarations to security.h.
(stop_transaction): Take "trans" HANDLE by reference and set it to
NULL after closing it.
(unlink_nt): If NtOpenFile fails due to a transactional error, stop
transaction and retry NtOpenFile. Simplify check for having to call
stop_transaction.
(rename): If NtOpenFile fails due to a transactional error, stop
transaction and retry NtOpenFile in both affected cases. Simplify check
for having to call stop_transaction and add comment from unlink_nt.
Corinna Vinschen