Check for STATUS_DELETE_PENDING on Windows.

1.  Update our open() wrapper to check for NT's STATUS_DELETE_PENDING
and translate it to Unix-like errors.  This is done with
RtlGetLastNtStatus(), which is dynamically loaded from ntdll.  A new
file win32ntdll.c centralizes lookup of NT functions, in case we decide
to add more in the future.

2.  Remove non-working code that was trying to do something similar for
stat(), and just reuse the open() wrapper code.  As a side effect,
stat() also gains resilience against "sharing violation" errors.

3.  Since stat() is used very early in process startup, remove the
requirement that the Win32 signal event has been created before
pgwin32_open_handle() is reached.  Instead, teach pg_usleep() to fall
back to a non-interruptible sleep if reached before the signal event is
available.

This could be back-patched, but for now it's in master only.  The
problem has apparently been with us for a long time and generated only a
few complaints.  Proposed patches trigger it more often, which led to
this investigation and fix.

Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Alexander Lakhin <exclusion@gmail.com>
Reviewed-by: Juan José Santamaría Flecha <juanjo.santamaria@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGJz_pZTF9mckn6XgSv69%2BjGwdgLkxZ6b3NWGLBCVjqUZA%40mail.gmail.com
(cherry picked from commit e2f0f8ed251d02c1eda79e1ca3cb3db2681e7a86)

Author: Thomas Munro <tmunro@postgresql.org>
Author: Alexandra Wang <alexandra.wang.oss@gmail.com>

1 files changed, 5 insertions, 154 deletions

diff --git a/src/port/win32stat.c b/src/port/win32stat.c
index acbf4c7e279..b4a05d50fb4 100644
--- a/src/port/win32stat.c
+++ b/src/port/win32stat.c
@@ -19,53 +19,6 @@
 #include <windows.h>
 
 /*
- * In order to support MinGW and MSVC2013 we use NtQueryInformationFile as an
- * alternative for GetFileInformationByHandleEx. It is loaded from the ntdll
- * library.
- */
-#if _WIN32_WINNT < 0x0600
-#include <winternl.h>
-
-#if !defined(__MINGW32__) && !defined(__MINGW64__)
-/* MinGW includes this in <winternl.h>, but it is missing in MSVC */
-typedef struct _FILE_STANDARD_INFORMATION
-{
-	LARGE_INTEGER AllocationSize;
-	LARGE_INTEGER EndOfFile;
-	ULONG		NumberOfLinks;
-	BOOLEAN		DeletePending;
-	BOOLEAN		Directory;
-} FILE_STANDARD_INFORMATION;
-#define FileStandardInformation 5
-#endif							/* !defined(__MINGW32__) &&
-								 * !defined(__MINGW64__) */
-
-typedef NTSTATUS (NTAPI * PFN_NTQUERYINFORMATIONFILE)
-			(IN HANDLE FileHandle,
-			 OUT PIO_STATUS_BLOCK IoStatusBlock,
-			 OUT PVOID FileInformation,
-			 IN ULONG Length,
-			 IN FILE_INFORMATION_CLASS FileInformationClass);
-
-static PFN_NTQUERYINFORMATIONFILE _NtQueryInformationFile = NULL;
-
-static HMODULE ntdll = NULL;
-
-/*
- * Load DLL file just once regardless of how many functions we load/call in it.
- */
-static void
-LoadNtdll(void)
-{
-	if (ntdll != NULL)
-		return;
-	ntdll = LoadLibraryEx("ntdll.dll", NULL, 0);
-}
-
-#endif							/* _WIN32_WINNT < 0x0600 */
-
-
-/*
  * Convert a FILETIME struct into a 64 bit time_t.
  */
 static __time64_t
@@ -162,120 +115,18 @@ int
 _pgstat64(const char *name, struct stat *buf)
 {
 	/*
-	 * We must use a handle so lstat() returns the information of the target
-	 * file.  To have a reliable test for ERROR_DELETE_PENDING, we use
-	 * NtQueryInformationFile from Windows 2000 or
-	 * GetFileInformationByHandleEx from Server 2008 / Vista.
+	 * Our open wrapper will report STATUS_DELETE_PENDING as ENOENT.  We
+	 * request FILE_FLAG_BACKUP_SEMANTICS so that we can open directories too,
+	 * for limited purposes.  We use the private handle-based version, so we
+	 * don't risk running out of fds.
 	 */
-	SECURITY_ATTRIBUTES sa;
 	HANDLE		hFile;
 	int			ret;
-#if _WIN32_WINNT < 0x0600
-	IO_STATUS_BLOCK ioStatus;
-	FILE_STANDARD_INFORMATION standardInfo;
-#else
-	FILE_STANDARD_INFO standardInfo;
-#endif
-
-	if (name == NULL || buf == NULL)
-	{
-		errno = EINVAL;
-		return -1;
-	}
 
-	/* fast not-exists check */
-	if (GetFileAttributes(name) == INVALID_FILE_ATTRIBUTES)
-	{
-		_dosmaperr(GetLastError());
-		return -1;
-	}
-
-	/* get a file handle as lightweight as we can */
-	sa.nLength = sizeof(SECURITY_ATTRIBUTES);
-	sa.bInheritHandle = TRUE;
-	sa.lpSecurityDescriptor = NULL;
-	hFile = CreateFile(name,
-					   GENERIC_READ,
-					   (FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE),
-					   &sa,
-					   OPEN_EXISTING,
-					   (FILE_FLAG_NO_BUFFERING | FILE_FLAG_BACKUP_SEMANTICS |
-						FILE_FLAG_OVERLAPPED),
-					   NULL);
+	hFile = pgwin32_open_handle(name, O_RDONLY, true);
 	if (hFile == INVALID_HANDLE_VALUE)
-	{
-		DWORD		err = GetLastError();
-
-		CloseHandle(hFile);
-		_dosmaperr(err);
 		return -1;
-	}
-
-	memset(&standardInfo, 0, sizeof(standardInfo));
-
-#if _WIN32_WINNT < 0x0600
-	if (_NtQueryInformationFile == NULL)
-	{
-		/* First time through: load ntdll.dll and find NtQueryInformationFile */
-		LoadNtdll();
-		if (ntdll == NULL)
-		{
-			DWORD		err = GetLastError();
-
-			CloseHandle(hFile);
-			_dosmaperr(err);
-			return -1;
-		}
-
-		_NtQueryInformationFile = (PFN_NTQUERYINFORMATIONFILE) (pg_funcptr_t)
-			GetProcAddress(ntdll, "NtQueryInformationFile");
-		if (_NtQueryInformationFile == NULL)
-		{
-			DWORD		err = GetLastError();
-
-			CloseHandle(hFile);
-			_dosmaperr(err);
-			return -1;
-		}
-	}
-
-	if (!NT_SUCCESS(_NtQueryInformationFile(hFile, &ioStatus, &standardInfo,
-											sizeof(standardInfo),
-											FileStandardInformation)))
-	{
-		DWORD		err = GetLastError();
-
-		CloseHandle(hFile);
-		_dosmaperr(err);
-		return -1;
-	}
-#else
-	if (!GetFileInformationByHandleEx(hFile, FileStandardInfo, &standardInfo,
-									  sizeof(standardInfo)))
-	{
-		DWORD		err = GetLastError();
-
-		CloseHandle(hFile);
-		_dosmaperr(err);
-		return -1;
-	}
-#endif							/* _WIN32_WINNT < 0x0600 */
-
-	if (standardInfo.DeletePending)
-	{
-		/*
-		 * File has been deleted, but is not gone from the filesystem yet.
-		 * This can happen when some process with FILE_SHARE_DELETE has it
-		 * open, and it will be fully removed once that handle is closed.
-		 * Meanwhile, we can't open it, so indicate that the file just doesn't
-		 * exist.
-		 */
-		CloseHandle(hFile);
-		errno = ENOENT;
-		return -1;
-	}
 
-	/* At last we can invoke fileinfo_to_stat */
 	ret = fileinfo_to_stat(hFile, buf);
 
 	CloseHandle(hFile);