fs.go

//go:build windows

package fs

import (
	"golang.org/x/sys/windows"

	"github.com/Microsoft/go-winio/internal/stringbuffer"
)

//go:generate go run github.com/Microsoft/go-winio/tools/mkwinsyscall -output zsyscall_windows.go fs.go

// https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew
//sys CreateFile(name string, access AccessMask, mode FileShareMode, sa *windows.SecurityAttributes, createmode FileCreationDisposition, attrs FileFlagOrAttribute, templatefile windows.Handle) (handle windows.Handle, err error) [failretval==windows.InvalidHandle] = CreateFileW

const NullHandle windows.Handle = 0

// AccessMask defines standard, specific, and generic rights.
//
// Used with CreateFile and NtCreateFile (and co.).
//
//	Bitmask:
//	 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
//	 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
//	+---------------+---------------+-------------------------------+
//	|G|G|G|G|Resvd|A| StandardRights|         SpecificRights        |
//	|R|W|E|A|     |S|               |                               |
//	+-+-------------+---------------+-------------------------------+
//
//	GR     Generic Read
//	GW     Generic Write
//	GE     Generic Exectue
//	GA     Generic All
//	Resvd  Reserved
//	AS     Access Security System
//
// https://learn.microsoft.com/en-us/windows/win32/secauthz/access-mask
//
// https://learn.microsoft.com/en-us/windows/win32/secauthz/generic-access-rights
//
// https://learn.microsoft.com/en-us/windows/win32/fileio/file-access-rights-constants
type AccessMask = windows.ACCESS_MASK

//nolint:revive // SNAKE_CASE is not idiomatic in Go, but aligned with Win32 API.
const (
	// Not actually any.
	//
	// For CreateFile: "query certain metadata such as file, directory, or device attributes without accessing that file or device"
	// https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew#parameters
	FILE_ANY_ACCESS AccessMask = 0

	GENERIC_READ           AccessMask = 0x8000_0000
	GENERIC_WRITE          AccessMask = 0x4000_0000
	GENERIC_EXECUTE        AccessMask = 0x2000_0000
	GENERIC_ALL            AccessMask = 0x1000_0000
	ACCESS_SYSTEM_SECURITY AccessMask = 0x0100_0000

	// Specific Object Access
	// from ntioapi.h

	FILE_READ_DATA      AccessMask = (0x0001) // file & pipe
	FILE_LIST_DIRECTORY AccessMask = (0x0001) // directory

	FILE_WRITE_DATA AccessMask = (0x0002) // file & pipe
	FILE_ADD_FILE   AccessMask = (0x0002) // directory

	FILE_APPEND_DATA          AccessMask = (0x0004) // file
	FILE_ADD_SUBDIRECTORY     AccessMask = (0x0004) // directory
	FILE_CREATE_PIPE_INSTANCE AccessMask = (0x0004) // named pipe

	FILE_READ_EA         AccessMask = (0x0008) // file & directory
	FILE_READ_PROPERTIES AccessMask = FILE_READ_EA

	FILE_WRITE_EA         AccessMask = (0x0010) // file & directory
	FILE_WRITE_PROPERTIES AccessMask = FILE_WRITE_EA

	FILE_EXECUTE  AccessMask = (0x0020) // file
	FILE_TRAVERSE AccessMask = (0x0020) // directory

	FILE_DELETE_CHILD AccessMask = (0x0040) // directory

	FILE_READ_ATTRIBUTES AccessMask = (0x0080) // all

	FILE_WRITE_ATTRIBUTES AccessMask = (0x0100) // all

	FILE_ALL_ACCESS      AccessMask = (STANDARD_RIGHTS_REQUIRED | SYNCHRONIZE | 0x1FF)
	FILE_GENERIC_READ    AccessMask = (STANDARD_RIGHTS_READ | FILE_READ_DATA | FILE_READ_ATTRIBUTES | FILE_READ_EA | SYNCHRONIZE)
	FILE_GENERIC_WRITE   AccessMask = (STANDARD_RIGHTS_WRITE | FILE_WRITE_DATA | FILE_WRITE_ATTRIBUTES | FILE_WRITE_EA | FILE_APPEND_DATA | SYNCHRONIZE)
	FILE_GENERIC_EXECUTE AccessMask = (STANDARD_RIGHTS_EXECUTE | FILE_READ_ATTRIBUTES | FILE_EXECUTE | SYNCHRONIZE)

	SPECIFIC_RIGHTS_ALL AccessMask = 0x0000FFFF

	// Standard Access
	// from ntseapi.h

	DELETE       AccessMask = 0x0001_0000
	READ_CONTROL AccessMask = 0x0002_0000
	WRITE_DAC    AccessMask = 0x0004_0000
	WRITE_OWNER  AccessMask = 0x0008_0000
	SYNCHRONIZE  AccessMask = 0x0010_0000

	STANDARD_RIGHTS_REQUIRED AccessMask = 0x000F_0000

	STANDARD_RIGHTS_READ    AccessMask = READ_CONTROL
	STANDARD_RIGHTS_WRITE   AccessMask = READ_CONTROL
	STANDARD_RIGHTS_EXECUTE AccessMask = READ_CONTROL

	STANDARD_RIGHTS_ALL AccessMask = 0x001F_0000
)

type FileShareMode uint32

//nolint:revive // SNAKE_CASE is not idiomatic in Go, but aligned with Win32 API.
const (
	FILE_SHARE_NONE        FileShareMode = 0x00
	FILE_SHARE_READ        FileShareMode = 0x01
	FILE_SHARE_WRITE       FileShareMode = 0x02
	FILE_SHARE_DELETE      FileShareMode = 0x04
	FILE_SHARE_VALID_FLAGS FileShareMode = 0x07
)

type FileCreationDisposition uint32

//nolint:revive // SNAKE_CASE is not idiomatic in Go, but aligned with Win32 API.
const (
	// from winbase.h

	CREATE_NEW        FileCreationDisposition = 0x01
	CREATE_ALWAYS     FileCreationDisposition = 0x02
	OPEN_EXISTING     FileCreationDisposition = 0x03
	OPEN_ALWAYS       FileCreationDisposition = 0x04
	TRUNCATE_EXISTING FileCreationDisposition = 0x05
)

// Create disposition values for NtCreate*
type NTFileCreationDisposition uint32

//nolint:revive // SNAKE_CASE is not idiomatic in Go, but aligned with Win32 API.
const (
	// From ntioapi.h

	FILE_SUPERSEDE           NTFileCreationDisposition = 0x00
	FILE_OPEN                NTFileCreationDisposition = 0x01
	FILE_CREATE              NTFileCreationDisposition = 0x02
	FILE_OPEN_IF             NTFileCreationDisposition = 0x03
	FILE_OVERWRITE           NTFileCreationDisposition = 0x04
	FILE_OVERWRITE_IF        NTFileCreationDisposition = 0x05
	FILE_MAXIMUM_DISPOSITION NTFileCreationDisposition = 0x05
)

// CreateFile and co. take flags or attributes together as one parameter.
// Define alias until we can use generics to allow both
//
// https://learn.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants
type FileFlagOrAttribute uint32

//nolint:revive // SNAKE_CASE is not idiomatic in Go, but aligned with Win32 API.
const (
	// from winnt.h

	FILE_FLAG_WRITE_THROUGH       FileFlagOrAttribute = 0x8000_0000
	FILE_FLAG_OVERLAPPED          FileFlagOrAttribute = 0x4000_0000
	FILE_FLAG_NO_BUFFERING        FileFlagOrAttribute = 0x2000_0000
	FILE_FLAG_RANDOM_ACCESS       FileFlagOrAttribute = 0x1000_0000
	FILE_FLAG_SEQUENTIAL_SCAN     FileFlagOrAttribute = 0x0800_0000
	FILE_FLAG_DELETE_ON_CLOSE     FileFlagOrAttribute = 0x0400_0000
	FILE_FLAG_BACKUP_SEMANTICS    FileFlagOrAttribute = 0x0200_0000
	FILE_FLAG_POSIX_SEMANTICS     FileFlagOrAttribute = 0x0100_0000
	FILE_FLAG_OPEN_REPARSE_POINT  FileFlagOrAttribute = 0x0020_0000
	FILE_FLAG_OPEN_NO_RECALL      FileFlagOrAttribute = 0x0010_0000
	FILE_FLAG_FIRST_PIPE_INSTANCE FileFlagOrAttribute = 0x0008_0000
)

// NtCreate* functions take a dedicated CreateOptions parameter.
//
// https://learn.microsoft.com/en-us/windows/win32/api/Winternl/nf-winternl-ntcreatefile
//
// https://learn.microsoft.com/en-us/windows/win32/devnotes/nt-create-named-pipe-file
type NTCreateOptions uint32

//nolint:revive // SNAKE_CASE is not idiomatic in Go, but aligned with Win32 API.
const (
	// From ntioapi.h

	FILE_DIRECTORY_FILE            NTCreateOptions = 0x0000_0001
	FILE_WRITE_THROUGH             NTCreateOptions = 0x0000_0002
	FILE_SEQUENTIAL_ONLY           NTCreateOptions = 0x0000_0004
	FILE_NO_INTERMEDIATE_BUFFERING NTCreateOptions = 0x0000_0008

	FILE_SYNCHRONOUS_IO_ALERT    NTCreateOptions = 0x0000_0010
	FILE_SYNCHRONOUS_IO_NONALERT NTCreateOptions = 0x0000_0020
	FILE_NON_DIRECTORY_FILE      NTCreateOptions = 0x0000_0040
	FILE_CREATE_TREE_CONNECTION  NTCreateOptions = 0x0000_0080

	FILE_COMPLETE_IF_OPLOCKED NTCreateOptions = 0x0000_0100
	FILE_NO_EA_KNOWLEDGE      NTCreateOptions = 0x0000_0200
	FILE_DISABLE_TUNNELING    NTCreateOptions = 0x0000_0400
	FILE_RANDOM_ACCESS        NTCreateOptions = 0x0000_0800

	FILE_DELETE_ON_CLOSE        NTCreateOptions = 0x0000_1000
	FILE_OPEN_BY_FILE_ID        NTCreateOptions = 0x0000_2000
	FILE_OPEN_FOR_BACKUP_INTENT NTCreateOptions = 0x0000_4000
	FILE_NO_COMPRESSION         NTCreateOptions = 0x0000_8000
)

type FileSQSFlag = FileFlagOrAttribute

//nolint:revive // SNAKE_CASE is not idiomatic in Go, but aligned with Win32 API.
const (
	// from winbase.h

	SECURITY_ANONYMOUS      FileSQSFlag = FileSQSFlag(SecurityAnonymous << 16)
	SECURITY_IDENTIFICATION FileSQSFlag = FileSQSFlag(SecurityIdentification << 16)
	SECURITY_IMPERSONATION  FileSQSFlag = FileSQSFlag(SecurityImpersonation << 16)
	SECURITY_DELEGATION     FileSQSFlag = FileSQSFlag(SecurityDelegation << 16)

	SECURITY_SQOS_PRESENT     FileSQSFlag = 0x0010_0000
	SECURITY_VALID_SQOS_FLAGS FileSQSFlag = 0x001F_0000
)

// GetFinalPathNameByHandle flags
//
// https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-getfinalpathnamebyhandlew#parameters
type GetFinalPathFlag uint32

//nolint:revive // SNAKE_CASE is not idiomatic in Go, but aligned with Win32 API.
const (
	GetFinalPathDefaultFlag GetFinalPathFlag = 0x0

	FILE_NAME_NORMALIZED GetFinalPathFlag = 0x0
	FILE_NAME_OPENED     GetFinalPathFlag = 0x8

	VOLUME_NAME_DOS  GetFinalPathFlag = 0x0
	VOLUME_NAME_GUID GetFinalPathFlag = 0x1
	VOLUME_NAME_NT   GetFinalPathFlag = 0x2
	VOLUME_NAME_NONE GetFinalPathFlag = 0x4
)

// getFinalPathNameByHandle facilitates calling the Windows API GetFinalPathNameByHandle
// with the given handle and flags. It transparently takes care of creating a buffer of the
// correct size for the call.
//
// https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-getfinalpathnamebyhandlew
func GetFinalPathNameByHandle(h windows.Handle, flags GetFinalPathFlag) (string, error) {
	b := stringbuffer.NewWString()
	//TODO: can loop infinitely if Win32 keeps returning the same (or a larger) n?
	for {
		n, err := windows.GetFinalPathNameByHandle(h, b.Pointer(), b.Cap(), uint32(flags))
		if err != nil {
			return "", err
		}
		// If the buffer wasn't large enough, n will be the total size needed (including null terminator).
		// Resize and try again.
		if n > b.Cap() {
			b.ResizeTo(n)
			continue
		}
		// If the buffer is large enough, n will be the size not including the null terminator.
		// Convert to a Go string and return.
		return b.String(), nil
	}
}