Add back LoadLibraryA fallback

src/syscall/dll_windows.go

@@ -44,7 +44,7 @@ func Syscall18(trap, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a
 
 func SyscallN(trap uintptr, args ...uintptr) (r1, r2 uintptr, err Errno)
 func loadlibrary(filename *uint16) (handle uintptr, err Errno)
-func loadsystemlibrary(filename *uint16) (handle uintptr, err Errno)
+func loadsystemlibrary(filename *uint16, absoluteFilepath *uint16) (handle uintptr, err Errno)
 func getprocaddress(handle uintptr, procname *uint8) (proc uintptr, err Errno)
 
 // A DLL implements access to a single DLL.
@@ -53,6 +53,26 @@ type DLL struct {
 	Handle Handle
 }
 
+// We use this for computing the absolute path for system DLLs on systems
+// where SEARCH_SYSTEM32 is not available.
+var systemDirectoryPrefix string
+
+func init() {
+	n := uint32(MAX_PATH)
+	for {
+		b := make([]uint16, n)
+		l, e := getSystemDirectory(&b[0], n)
+		if e != nil {
+			panic("Unable to determine system directory: " + e.Error())
+		}
+		if l <= n {
+			systemDirectoryPrefix = UTF16ToString(b[:l]) + "\\"
+			break
+		}
+		n = l
+	}
+}
+
 // LoadDLL loads the named DLL file into memory.
 //
 // If name is not an absolute path and is not a known system DLL used by
@@ -69,7 +89,11 @@ func LoadDLL(name string) (*DLL, error) {
 	var h uintptr
 	var e Errno
 	if sysdll.IsSystemDLL[name] {
-		h, e = loadsystemlibrary(namep)
+		absoluteFilepathp, err := UTF16PtrFromString(systemDirectoryPrefix + name)
+		if err != nil {
+			return nil, err
+		}
+		h, e = loadsystemlibrary(namep, absoluteFilepathp)
 	} else {
 		h, e = loadlibrary(namep)
 	}

src/syscall/security_windows.go

@@ -290,6 +290,7 @@ type Tokenprimarygroup struct {
 //sys	OpenProcessToken(h Handle, access uint32, token *Token) (err error) = advapi32.OpenProcessToken
 //sys	GetTokenInformation(t Token, infoClass uint32, info *byte, infoLen uint32, returnedLen *uint32) (err error) = advapi32.GetTokenInformation
 //sys	GetUserProfileDirectory(t Token, dir *uint16, dirLen *uint32) (err error) = userenv.GetUserProfileDirectoryW
+//sys	getSystemDirectory(dir *uint16, dirLen uint32) (len uint32, err error) = kernel32.GetSystemDirectoryW
 
 // An access token contains the security information for a logon session.
 // The system creates an access token when a user logs on, and every

src/syscall/zsyscall_windows.go

@@ -128,6 +128,7 @@ var (
 	procGetShortPathNameW                  = modkernel32.NewProc("GetShortPathNameW")
 	procGetStartupInfoW                    = modkernel32.NewProc("GetStartupInfoW")
 	procGetStdHandle                       = modkernel32.NewProc("GetStdHandle")
+	procGetSystemDirectoryW                = modkernel32.NewProc("GetSystemDirectoryW")
 	procGetSystemTimeAsFileTime            = modkernel32.NewProc("GetSystemTimeAsFileTime")
 	procGetTempPathW                       = modkernel32.NewProc("GetTempPathW")
 	procGetTimeZoneInformation             = modkernel32.NewProc("GetTimeZoneInformation")
@@ -870,6 +871,15 @@ func GetStdHandle(stdhandle int) (handle Handle, err error) {
 	return
 }
 
+func getSystemDirectory(dir *uint16, dirLen uint32) (len uint32, err error) {
+	r0, _, e1 := Syscall(procGetSystemDirectoryW.Addr(), 2, uintptr(unsafe.Pointer(dir)), uintptr(dirLen), 0)
+	len = uint32(r0)
+	if len == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func GetSystemTimeAsFileTime(time *Filetime) {
 	Syscall(procGetSystemTimeAsFileTime.Addr(), 1, uintptr(unsafe.Pointer(time)), 0, 0)
 	return