Styjun

I want to execute HelloWorldConsole.exe with an shipped Mono Framework through Go.

So I want to call mono-2.0-sgen.dll funtion "mono_main" to execute the exe.
mono-2.0-sgen.dll is a PE32 executable for MS Windows, see.

But I get the error "not a valid Win32 application"

_ = os.Setenv("MONO_PATH", `monolibmono4.5;C:DEVHelloWorldConsoleHelloWorldConsolebinDebug`)
_ = os.Setenv("MONO_CFG_DIR", `"C:Program Files (x86)Monoetc"`)
_ = os.Setenv("MONO_CONFIG", `"C:Program Files (x86)Monoetcmonoconfig"`)

mono := `C:Program Files (x86)Monobinmono-2.0-sgen.dll`
app := `C:DEVHelloWorldConsoleHelloWorldConsolebinDebugHelloWorldConsole.exe`

fmt.Println("Execute")

var mod = syscall.NewLazyDLL(mono)
var proc = mod.NewProc("mono_main")

ret, _, _ := proc.Call(0,
 uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr("mono.exe"))),
 uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(app))) )

Same behavior with windows.NewLazySystemDLL

dll := windows.NewLazySystemDLL(mono)
lazyProc := dll.NewProc("mono_main")
lazyProc.Call()

Function Name

Full Error:

panic: Failed to load C:Program Files (x86)Monobinmono-2.0-sgen.dll: %1 is **not a valid Win32 application**.

%1 is not a valid Win32 application

The error %1 is not a valid Win32 application is a discription of Win32 error code from windows itself.

The Win32 error code itself is 0x000000C1 ERROR_BAD_EXE_FORMAT, see docs.microsoft.com.

BAD_EXE_FORMATmeans you call a x86 dll within a x64 process. You must use the x86 variant of Go, e.g. go1.12.1.windows-386.zip from https://golang.org/dl/.

Now must change the GOROOT and PATH to the extracted bin folder and then you are ready to go.

Type of Arguments

When you call mono_main you need to consume the this function in the right way.
If you take an look at the implementation you see that the signature is int mono_main (int argc, char* argv[]);. argc and argv is a widly used pattern, see here.

Working Sample

func main() 
 _ = os.Setenv("MONO_PATH", `C:DEVHelloWorldConsoleHelloWorldConsolebinx86Debugmonolibmono4.5;C:DEVHelloWorldConsoleHelloWorldConsolebinx86Debug`)
 _ = os.Setenv("MONO_CFG_DIR", `C:DEVHelloWorhpm.goldConsoleHelloWorldConsolebinx86Debugmonoetc`)
 _ = os.Setenv("MONO_CONFIG", `C:DEVHelloWorldConsoleHelloWorldConsolebinx86Debugmonoetcmonoconfig`)

 _ = os.Chdir(`C:DEVHelloWorldConsoleHelloWorldConsolebinx86Debug`)

 mono := `C:DEVHelloWorldConsoleHelloWorldConsolebinx86Debugmonobinmono-2.0-sgen.dll`

 // https://github.com/mono/mono/blob/c5b88ec4f323f2bdb7c7d0a595ece28dae66579c/mcs/tools/mkbundle/template_main.c#L1
 dll := windows.NewLazySystemDLL(mono)
 lazyProc := dll.NewProc("mono_main")

 dotNetAssembly := []byte(`HelloWorldConsole.exe`)

 var argummentData [260]byte
 ptr := unsafe.Pointer(&argummentData)

 copy(argummentData[:], dotNetAssembly)

 args := [2]uintptr0, uintptr(ptr)

 _, _, _ = lazyProc.Call(2, uintptr(unsafe.Pointer(&args)))