os: add new tests for symbolic links and directory junctions

Updates #15978
Updates #16145

Change-Id: I161f5bc97d41c08bf5e1405ccafa86232d70886d
Reviewed-on: https://go-review.googlesource.com/25320
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

src/internal/syscall/windows/mksyscall.go

@@ -4,4 +4,4 @@
 
 package windows
 
-//go:generate go run $GOROOT/src/syscall/mksyscall_windows.go -output zsyscall_windows.go syscall_windows.go
+//go:generate go run $GOROOT/src/syscall/mksyscall_windows.go -output zsyscall_windows.go syscall_windows.go security_windows.go

src/internal/syscall/windows/reparse_windows.go

+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package windows
+
+const (
+	FSCTL_SET_REPARSE_POINT    = 0x000900A4
+	IO_REPARSE_TAG_MOUNT_POINT = 0xA0000003
+
+	SYMLINK_FLAG_RELATIVE = 1
+)
+
+// These structures are described
+// in https://msdn.microsoft.com/en-us/library/cc232007.aspx
+// and https://msdn.microsoft.com/en-us/library/cc232006.aspx.
+
+// REPARSE_DATA_BUFFER_HEADER is a common part of REPARSE_DATA_BUFFER structure.
+type REPARSE_DATA_BUFFER_HEADER struct {
+	ReparseTag uint32
+	// The size, in bytes, of the reparse data that follows
+	// the common portion of the REPARSE_DATA_BUFFER element.
+	// This value is the length of the data starting at the
+	// SubstituteNameOffset field.
+	ReparseDataLength uint16
+	Reserved          uint16
+}
+
+type SymbolicLinkReparseBuffer struct {
+	// The integer that contains the offset, in bytes,
+	// of the substitute name string in the PathBuffer array,
+	// computed as an offset from byte 0 of PathBuffer. Note that
+	// this offset must be divided by 2 to get the array index.
+	SubstituteNameOffset uint16
+	// The integer that contains the length, in bytes, of the
+	// substitute name string. If this string is null-terminated,
+	// SubstituteNameLength does not include the Unicode null character.
+	SubstituteNameLength uint16
+	// PrintNameOffset is similar to SubstituteNameOffset.
+	PrintNameOffset uint16
+	// PrintNameLength is similar to SubstituteNameLength.
+	PrintNameLength uint16
+	// Flags specifies whether the substitute name is a full path name or
+	// a path name relative to the directory containing the symbolic link.
+	Flags      uint32
+	PathBuffer [1]uint16
+}
+
+type MountPointReparseBuffer struct {
+	// The integer that contains the offset, in bytes,
+	// of the substitute name string in the PathBuffer array,
+	// computed as an offset from byte 0 of PathBuffer. Note that
+	// this offset must be divided by 2 to get the array index.
+	SubstituteNameOffset uint16
+	// The integer that contains the length, in bytes, of the
+	// substitute name string. If this string is null-terminated,
+	// SubstituteNameLength does not include the Unicode null character.
+	SubstituteNameLength uint16
+	// PrintNameOffset is similar to SubstituteNameOffset.
+	PrintNameOffset uint16
+	// PrintNameLength is similar to SubstituteNameLength.
+	PrintNameLength uint16
+	PathBuffer      [1]uint16
+}

src/internal/syscall/windows/security_windows.go

+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package windows
+
+import (
+	"syscall"
+)
+
+const (
+	SecurityAnonymous      = 0
+	SecurityIdentification = 1
+	SecurityImpersonation  = 2
+	SecurityDelegation     = 3
+)
+
+//sys	ImpersonateSelf(impersonationlevel uint32) (err error) = advapi32.ImpersonateSelf
+//sys	RevertToSelf() (err error) = advapi32.RevertToSelf
+
+const (
+	TOKEN_ADJUST_PRIVILEGES = 0x0020
+	SE_PRIVILEGE_ENABLED    = 0x00000002
+)
+
+type LUID struct {
+	LowPart  uint32
+	HighPart int32
+}
+
+type LUID_AND_ATTRIBUTES struct {
+	Luid       LUID
+	Attributes uint32
+}
+
+type TOKEN_PRIVILEGES struct {
+	PrivilegeCount uint32
+	Privileges     [1]LUID_AND_ATTRIBUTES
+}
+
+//sys	OpenThreadToken(h syscall.Handle, access uint32, openasself bool, token *syscall.Token) (err error) = advapi32.OpenThreadToken
+//sys	LookupPrivilegeValue(systemname *uint16, name *uint16, luid *LUID) (err error) = advapi32.LookupPrivilegeValueW
+//sys	adjustTokenPrivileges(token syscall.Token, disableAllPrivileges bool, newstate *TOKEN_PRIVILEGES, buflen uint32, prevstate *TOKEN_PRIVILEGES, returnlen *uint32) (ret uint32, err error) [true] = advapi32.AdjustTokenPrivileges
+
+func AdjustTokenPrivileges(token syscall.Token, disableAllPrivileges bool, newstate *TOKEN_PRIVILEGES, buflen uint32, prevstate *TOKEN_PRIVILEGES, returnlen *uint32) error {
+	ret, err := adjustTokenPrivileges(token, disableAllPrivileges, newstate, buflen, prevstate, returnlen)
+	if ret == 0 {
+		// AdjustTokenPrivileges call failed
+		return err
+	}
+	// AdjustTokenPrivileges call succeeded
+	if err == syscall.EINVAL {
+		// GetLastError returned ERROR_SUCCESS
+		return nil
+	}
+	return err
+}

src/internal/syscall/windows/syscall_windows.go

@@ -140,3 +140,4 @@ func Rename(oldpath, newpath string) error {
 //sys	GetACP() (acp uint32) = kernel32.GetACP
 //sys	GetConsoleCP() (ccp uint32) = kernel32.GetConsoleCP
 //sys	MultiByteToWideChar(codePage uint32, dwFlags uint32, str *byte, nstr int32, wchar *uint16, nwchar int32) (nwrite int32, err error) = kernel32.MultiByteToWideChar
+//sys	GetCurrentThread() (pseudoHandle syscall.Handle, err error) = kernel32.GetCurrentThread

src/internal/syscall/windows/zsyscall_windows.go

@@ -38,6 +38,7 @@ func errnoErr(e syscall.Errno) error {
 var (
 	modiphlpapi = syscall.NewLazyDLL(sysdll.Add("iphlpapi.dll"))
 	modkernel32 = syscall.NewLazyDLL(sysdll.Add("kernel32.dll"))
+	modadvapi32 = syscall.NewLazyDLL(sysdll.Add("advapi32.dll"))
 
 	procGetAdaptersAddresses  = modiphlpapi.NewProc("GetAdaptersAddresses")
 	procGetComputerNameExW    = modkernel32.NewProc("GetComputerNameExW")
@@ -45,6 +46,12 @@ var (
 	procGetACP                = modkernel32.NewProc("GetACP")
 	procGetConsoleCP          = modkernel32.NewProc("GetConsoleCP")
 	procMultiByteToWideChar   = modkernel32.NewProc("MultiByteToWideChar")
+	procGetCurrentThread      = modkernel32.NewProc("GetCurrentThread")
+	procImpersonateSelf       = modadvapi32.NewProc("ImpersonateSelf")
+	procRevertToSelf          = modadvapi32.NewProc("RevertToSelf")
+	procOpenThreadToken       = modadvapi32.NewProc("OpenThreadToken")
+	procLookupPrivilegeValueW = modadvapi32.NewProc("LookupPrivilegeValueW")
+	procAdjustTokenPrivileges = modadvapi32.NewProc("AdjustTokenPrivileges")
 )
 
 func GetAdaptersAddresses(family uint32, flags uint32, reserved uintptr, adapterAddresses *IpAdapterAddresses, sizePointer *uint32) (errcode error) {
@@ -103,3 +110,89 @@ func MultiByteToWideChar(codePage uint32, dwFlags uint32, str *byte, nstr int32,
 	}
 	return
 }
+
+func GetCurrentThread() (pseudoHandle syscall.Handle, err error) {
+	r0, _, e1 := syscall.Syscall(procGetCurrentThread.Addr(), 0, 0, 0, 0)
+	pseudoHandle = syscall.Handle(r0)
+	if pseudoHandle == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func ImpersonateSelf(impersonationlevel uint32) (err error) {
+	r1, _, e1 := syscall.Syscall(procImpersonateSelf.Addr(), 1, uintptr(impersonationlevel), 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func RevertToSelf() (err error) {
+	r1, _, e1 := syscall.Syscall(procRevertToSelf.Addr(), 0, 0, 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func OpenThreadToken(h syscall.Handle, access uint32, openasself bool, token *syscall.Token) (err error) {
+	var _p0 uint32
+	if openasself {
+		_p0 = 1
+	} else {
+		_p0 = 0
+	}
+	r1, _, e1 := syscall.Syscall6(procOpenThreadToken.Addr(), 4, uintptr(h), uintptr(access), uintptr(_p0), uintptr(unsafe.Pointer(token)), 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func LookupPrivilegeValue(systemname *uint16, name *uint16, luid *LUID) (err error) {
+	r1, _, e1 := syscall.Syscall(procLookupPrivilegeValueW.Addr(), 3, uintptr(unsafe.Pointer(systemname)), uintptr(unsafe.Pointer(name)), uintptr(unsafe.Pointer(luid)))
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func adjustTokenPrivileges(token syscall.Token, disableAllPrivileges bool, newstate *TOKEN_PRIVILEGES, buflen uint32, prevstate *TOKEN_PRIVILEGES, returnlen *uint32) (ret uint32, err error) {
+	var _p0 uint32
+	if disableAllPrivileges {
+		_p0 = 1
+	} else {
+		_p0 = 0
+	}
+	r0, _, e1 := syscall.Syscall6(procAdjustTokenPrivileges.Addr(), 6, uintptr(token), uintptr(_p0), uintptr(unsafe.Pointer(newstate)), uintptr(buflen), uintptr(unsafe.Pointer(prevstate)), uintptr(unsafe.Pointer(returnlen)))
+	ret = uint32(r0)
+	if true {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}