fscache: teach fscache to use NtQueryDirectoryFile

compat/win32/fscache.c

@@ -4,6 +4,7 @@
 #include "fscache.h"
 #include "config.h"
 #include "../../mem-pool.h"
+#include "ntifs.h"
 
 static volatile long initialized;
 static DWORD dwTlsIndex;
@@ -23,6 +24,7 @@ struct fscache {
 	unsigned int opendir_requests;
 	unsigned int fscache_requests;
 	unsigned int fscache_misses;
+	WCHAR buffer[64 * 1024];
 };
 static struct trace_key trace_fscache = TRACE_KEY_INIT(FSCACHE);
 
@@ -145,20 +147,44 @@ static void fsentry_release(struct fsentry *fse)
 	InterlockedDecrement(&(fse->refcnt));
 }
 
+static int xwcstoutfn(char *utf, int utflen, const wchar_t *wcs, int wcslen)
+{
+	if (!wcs || !utf || utflen < 1) {
+		errno = EINVAL;
+		return -1;
+	}
+	utflen = WideCharToMultiByte(CP_UTF8, 0, wcs, wcslen, utf, utflen, NULL, NULL);
+	if (utflen)
+		return utflen;
+	errno = ERANGE;
+	return -1;
+}
+
 /*
- * Allocate and initialize an fsentry from a WIN32_FIND_DATA structure.
+ * Allocate and initialize an fsentry from a FILE_FULL_DIR_INFORMATION structure.
  */
 static struct fsentry *fseentry_create_entry(struct fscache *cache, struct fsentry *list,
-		const WIN32_FIND_DATAW *fdata)
+		PFILE_FULL_DIR_INFORMATION fdata)
 {
 	char buf[MAX_PATH * 3];
 	int len;
 	struct fsentry *fse;
-	len = xwcstoutf(buf, fdata->cFileName, ARRAY_SIZE(buf));
+
+	len = xwcstoutfn(buf, ARRAY_SIZE(buf), fdata->FileName, fdata->FileNameLength / sizeof(wchar_t));
 
 	fse = fsentry_alloc(cache, list, buf, len);
 
-	if (fdata->dwReserved0 == IO_REPARSE_TAG_SYMLINK &&
+	/*
+	 * On certain Windows versions, host directories mapped into
+	 * Windows Containers ("Volumes", see https://docs.docker.com/storage/volumes/)
+	 * look like symbolic links, but their targets are paths that
+	 * are valid only in kernel mode.
+	 *
+	 * Let's work around this by detecting that situation and
+	 * telling Git that these are *not* symbolic links.
+	 */
+	if (fdata->FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT &&
+	    fdata->EaSize == IO_REPARSE_TAG_SYMLINK &&
 	    sizeof(buf) > (list ? list->len + 1 : 0) + fse->len + 1 &&
 	    is_inside_windows_container()) {
 		size_t off = 0;
@@ -171,13 +197,13 @@ static struct fsentry *fseentry_create_entry(struct fscache *cache, struct fsent
 		buf[off + fse->len] = '\0';
 	}
 
-	fse->st_mode = file_attr_to_st_mode(fdata->dwFileAttributes,
-			fdata->dwReserved0, buf);
+	fse->st_mode = file_attr_to_st_mode(fdata->FileAttributes,
+			fdata->EaSize, buf);
 	fse->st_size = S_ISLNK(fse->st_mode) ? MAX_LONG_PATH :
-			fdata->nFileSizeLow | (((off_t) fdata->nFileSizeHigh) << 32);
-	filetime_to_timespec(&(fdata->ftLastAccessTime), &(fse->st_atim));
-	filetime_to_timespec(&(fdata->ftLastWriteTime), &(fse->st_mtim));
-	filetime_to_timespec(&(fdata->ftCreationTime), &(fse->st_ctim));
+			fdata->EndOfFile.LowPart | (((off_t)fdata->EndOfFile.HighPart) << 32);
+	filetime_to_timespec((FILETIME *)&(fdata->LastAccessTime), &(fse->st_atim));
+	filetime_to_timespec((FILETIME *)&(fdata->LastWriteTime), &(fse->st_mtim));
+	filetime_to_timespec((FILETIME *)&(fdata->CreationTime), &(fse->st_ctim));
 
 	return fse;
 }
@@ -190,8 +216,10 @@ static struct fsentry *fseentry_create_entry(struct fscache *cache, struct fsent
 static struct fsentry *fsentry_create_list(struct fscache *cache, const struct fsentry *dir,
 					   int *dir_not_found)
 {
-	wchar_t pattern[MAX_LONG_PATH + 2]; /* + 2 for "\*" */
-	WIN32_FIND_DATAW fdata;
+	wchar_t pattern[MAX_LONG_PATH];
+	NTSTATUS status;
+	IO_STATUS_BLOCK iosb;
+	PFILE_FULL_DIR_INFORMATION di;
 	HANDLE h;
 	int wlen;
 	struct fsentry *list, **phead;
@@ -204,18 +232,18 @@ static struct fsentry *fsentry_create_list(struct fscache *cache, const struct f
 			dir->len, MAX_PATH - 2, core_long_paths)) < 0)
 		return NULL;
 
-	/*
-	 * append optional '\' and wildcard '*'. Note: we need to use '\' as
-	 * Windows doesn't translate '/' to '\' for "\\?\"-prefixed paths.
-	 */
-	if (wlen)
-		pattern[wlen++] = '\\';
-	pattern[wlen++] = '*';
-	pattern[wlen] = 0;
-
-	/* open find handle */
-	h = FindFirstFileExW(pattern, FindExInfoBasic, &fdata, FindExSearchNameMatch,
-		NULL, FIND_FIRST_EX_LARGE_FETCH);
+	/* handle CWD */
+	if (!wlen) {
+		wlen = GetCurrentDirectoryW(ARRAY_SIZE(pattern), pattern);
+		if (!wlen || wlen >= ARRAY_SIZE(pattern)) {
+			errno = wlen ? ENAMETOOLONG : err_win_to_posix(GetLastError());
+			return NULL;
+		}
+	}
+
+	h = CreateFileW(pattern, FILE_LIST_DIRECTORY,
+		FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+		NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
 	if (h == INVALID_HANDLE_VALUE) {
 		err = GetLastError();
 		*dir_not_found = 1; /* or empty directory */
@@ -231,22 +259,55 @@ static struct fsentry *fsentry_create_list(struct fscache *cache, const struct f
 
 	/* walk directory and build linked list of fsentry structures */
 	phead = &list->next;
-	do {
-		*phead = fseentry_create_entry(cache, list, &fdata);
+	status = NtQueryDirectoryFile(h, NULL, 0, 0, &iosb, cache->buffer,
+		sizeof(cache->buffer), FileFullDirectoryInformation, FALSE, NULL, FALSE);
+	if (!NT_SUCCESS(status)) {
+		/*
+		 * NtQueryDirectoryFile returns STATUS_INVALID_PARAMETER when
+		 * asked to enumerate an invalid directory (ie it is a file
+		 * instead of a directory).  Verify that is the actual cause
+		 * of the error.
+		*/
+		if (status == STATUS_INVALID_PARAMETER) {
+			DWORD attributes = GetFileAttributesW(pattern);
+			if (!(attributes & FILE_ATTRIBUTE_DIRECTORY))
+				status = ERROR_DIRECTORY;
+		}
+		goto Error;
+	}
+	di = (PFILE_FULL_DIR_INFORMATION)(cache->buffer);
+	for (;;) {
+
+		*phead = fseentry_create_entry(cache, list, di);
 		phead = &(*phead)->next;
-	} while (FindNextFileW(h, &fdata));
 
-	/* remember result of last FindNextFile, then close find handle */
-	err = GetLastError();
-	FindClose(h);
+		/* If there is no offset in the entry, the buffer has been exhausted. */
+		if (di->NextEntryOffset == 0) {
+			status = NtQueryDirectoryFile(h, NULL, 0, 0, &iosb, cache->buffer,
+				sizeof(cache->buffer), FileFullDirectoryInformation, FALSE, NULL, FALSE);
+			if (!NT_SUCCESS(status)) {
+				if (status == STATUS_NO_MORE_FILES)
+					break;
+				goto Error;
+			}
+
+			di = (PFILE_FULL_DIR_INFORMATION)(cache->buffer);
+			continue;
+		}
+
+		/* Advance to the next entry. */
+		di = (PFILE_FULL_DIR_INFORMATION)(((PUCHAR)di) + di->NextEntryOffset);
+	}
 
-	/* return the list if we've got all the files */
-	if (err == ERROR_NO_MORE_FILES)
-		return list;
+	CloseHandle(h);
+	return list;
 
-	/* otherwise release the list and return error */
+Error:
+	errno = (status == ERROR_DIRECTORY) ? ENOTDIR : err_win_to_posix(status);
+	trace_printf_key(&trace_fscache, "fscache: error(%d) unable to query directory contents '%.*s'\n",
+		errno, dir->len, dir->name);
+	CloseHandle(h);
 	fsentry_release(list);
-	errno = err_win_to_posix(err);
 	return NULL;
 }
 

compat/win32/ntifs.h

@@ -0,0 +1,131 @@
+#ifndef _NTIFS_
+#define _NTIFS_
+
+/*
+ * Copy necessary structures and definitions out of the Windows DDK
+ * to enable calling NtQueryDirectoryFile()
+ */
+
+typedef _Return_type_success_(return >= 0) LONG NTSTATUS;
+#define NT_SUCCESS(Status)  (((NTSTATUS)(Status)) >= 0)
+
+typedef struct _UNICODE_STRING {
+	USHORT Length;
+	USHORT MaximumLength;
+#ifdef MIDL_PASS
+	[size_is(MaximumLength / 2), length_is((Length) / 2)] USHORT * Buffer;
+#else // MIDL_PASS
+	_Field_size_bytes_part_(MaximumLength, Length) PWCH   Buffer;
+#endif // MIDL_PASS
+} UNICODE_STRING;
+typedef UNICODE_STRING *PUNICODE_STRING;
+typedef const UNICODE_STRING *PCUNICODE_STRING;
+
+typedef enum _FILE_INFORMATION_CLASS {
+	FileDirectoryInformation = 1,
+	FileFullDirectoryInformation,
+	FileBothDirectoryInformation,
+	FileBasicInformation,
+	FileStandardInformation,
+	FileInternalInformation,
+	FileEaInformation,
+	FileAccessInformation,
+	FileNameInformation,
+	FileRenameInformation,
+	FileLinkInformation,
+	FileNamesInformation,
+	FileDispositionInformation,
+	FilePositionInformation,
+	FileFullEaInformation,
+	FileModeInformation,
+	FileAlignmentInformation,
+	FileAllInformation,
+	FileAllocationInformation,
+	FileEndOfFileInformation,
+	FileAlternateNameInformation,
+	FileStreamInformation,
+	FilePipeInformation,
+	FilePipeLocalInformation,
+	FilePipeRemoteInformation,
+	FileMailslotQueryInformation,
+	FileMailslotSetInformation,
+	FileCompressionInformation,
+	FileObjectIdInformation,
+	FileCompletionInformation,
+	FileMoveClusterInformation,
+	FileQuotaInformation,
+	FileReparsePointInformation,
+	FileNetworkOpenInformation,
+	FileAttributeTagInformation,
+	FileTrackingInformation,
+	FileIdBothDirectoryInformation,
+	FileIdFullDirectoryInformation,
+	FileValidDataLengthInformation,
+	FileShortNameInformation,
+	FileIoCompletionNotificationInformation,
+	FileIoStatusBlockRangeInformation,
+	FileIoPriorityHintInformation,
+	FileSfioReserveInformation,
+	FileSfioVolumeInformation,
+	FileHardLinkInformation,
+	FileProcessIdsUsingFileInformation,
+	FileNormalizedNameInformation,
+	FileNetworkPhysicalNameInformation,
+	FileIdGlobalTxDirectoryInformation,
+	FileIsRemoteDeviceInformation,
+	FileAttributeCacheInformation,
+	FileNumaNodeInformation,
+	FileStandardLinkInformation,
+	FileRemoteProtocolInformation,
+	FileMaximumInformation
+} FILE_INFORMATION_CLASS, *PFILE_INFORMATION_CLASS;
+
+typedef struct _FILE_FULL_DIR_INFORMATION {
+	ULONG NextEntryOffset;
+	ULONG FileIndex;
+	LARGE_INTEGER CreationTime;
+	LARGE_INTEGER LastAccessTime;
+	LARGE_INTEGER LastWriteTime;
+	LARGE_INTEGER ChangeTime;
+	LARGE_INTEGER EndOfFile;
+	LARGE_INTEGER AllocationSize;
+	ULONG FileAttributes;
+	ULONG FileNameLength;
+	ULONG EaSize;
+	WCHAR FileName[1];
+} FILE_FULL_DIR_INFORMATION, *PFILE_FULL_DIR_INFORMATION;
+
+typedef struct _IO_STATUS_BLOCK {
+	union {
+		NTSTATUS Status;
+		PVOID Pointer;
+	} DUMMYUNIONNAME;
+	ULONG_PTR Information;
+} IO_STATUS_BLOCK, *PIO_STATUS_BLOCK;
+
+typedef VOID
+(NTAPI *PIO_APC_ROUTINE)(
+	IN PVOID ApcContext,
+	IN PIO_STATUS_BLOCK IoStatusBlock,
+	IN ULONG Reserved);
+
+NTSYSCALLAPI
+NTSTATUS
+NTAPI
+NtQueryDirectoryFile(
+	_In_ HANDLE FileHandle,
+	_In_opt_ HANDLE Event,
+	_In_opt_ PIO_APC_ROUTINE ApcRoutine,
+	_In_opt_ PVOID ApcContext,
+	_Out_ PIO_STATUS_BLOCK IoStatusBlock,
+	_Out_writes_bytes_(Length) PVOID FileInformation,
+	_In_ ULONG Length,
+	_In_ FILE_INFORMATION_CLASS FileInformationClass,
+	_In_ BOOLEAN ReturnSingleEntry,
+	_In_opt_ PUNICODE_STRING FileName,
+	_In_ BOOLEAN RestartScan
+);
+
+#define STATUS_NO_MORE_FILES             ((NTSTATUS)0x80000006L)
+
+#endif