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Cygwin: drop disabled O_TMPFILE POSIX unlink code 

The commit message of commit 07e0a9584f
and the expectation set therein, are wrong.

There's no POSIX semantics allowing to link a file with a link
count of 0 and making it available in the file system again.
In fact, the Linux linkat extension AT_EMPTY_PATH explicitely
disallows to link a file descriptor to a file with a link count
of 0, except for O_TMPFILE without O_EXCL.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen 2019-01-04 11:00:57 +01:00
parent 353ebae304
commit 34d9bb7093
1 changed files with 0 additions and 40 deletions
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40
winsup/cygwin/syscalls.cc
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@ -1467,46 +1467,6 @@ open (const char *unix_path, int flags, ...)
if ((fh->is_fs_special () && fh->device_access_denied (flags))
|| !fh->open_with_arch (flags, mode & 07777))
__leave; /* errno already set */
#if 0
/* Don't use W10 1709 POSIX unlink semantics here.
Including W10 1809, NtSetInformationFile(FileLinkInformation) on a
HANDLE to a file unlinked with POSIX semantics fails with
STATUS_ACCESS_DENIED. Trying to remove the delete disposition on
the file prior to calling link fails with STATUS_FILE_DELETED.
This breaks
fd = open(O_TMPFILE);
linkat("/proc/self/fd/<fd>);
semantics. */
if ((flags & O_TMPFILE) && wincap.has_posix_file_info ()
&& !fh->pc.isremote () && fh->pc.fs_is_ntfs ())
{
HANDLE del_h;
OBJECT_ATTRIBUTES attr;
NTSTATUS status;
IO_STATUS_BLOCK io;
FILE_DISPOSITION_INFORMATION_EX fdie;
status = NtOpenFile (&del_h, DELETE,
fh->pc.init_reopen_attr (attr, fh->get_handle ()), &io,
FILE_SHARE_VALID_FLAGS, FILE_OPEN_FOR_BACKUP_INTENT);
if (!NT_SUCCESS (status))
debug_printf ("reopening tmpfile handle failed, status %y", status);
else
{
fdie.Flags = FILE_DISPOSITION_DELETE
| FILE_DISPOSITION_POSIX_SEMANTICS;
status = NtSetInformationFile (del_h, &io, &fdie, sizeof fdie,
FileDispositionInformationEx);
if (!NT_SUCCESS (status))
debug_printf ("Setting POSIX delete disposition on tmpfile "
"failed, status = %y", status);
NtClose (del_h);
}
}
#endif
fd = fh;
if (fd <= 2)
set_std_handle (fd);