EnumProcessModules returns 0 with error 299 - winapi

Question

I'm currently trying to enumerate all the modules of a supsended 32-bits process I've previously created from my 32-bits program, my Windows is 64-bits.
(I've already read all the other topics on that problem).
Here is the code:
let a = CreateProcessA(
"C:\\Program Files (x86)\\GlassWire\\GlassWire.exe\0".as_ptr(),
null_mut(), null_mut(), null_mut(),
false,
0x00000004,
null_mut(), null_mut(), SI, PI);
println!("{}", GetLastError());
let mut buffer: [*mut c_void;10] = [0 as *mut c_void;10];
WaitForInputIdle((*PI).hProcess as *mut c_void, -1);
let result = EnumProcessModules(
(*PI).hProcess as *mut c_void,
buffer.as_ptr() as *mut c_void,
10, null_mut());
println!("EnumProcessModules([...]) = {} - {}", result, GetLastError());
let mut index: usize = 0x0;
let mut modname: [u8;1024] = [0;1024];
while(transmute::<*mut c_void, u32>(buffer[index]) != 0x0){
GetModuleFileNameExA((*PI).hProcess as *mut c_void, buffer[index], modname.as_ptr() as *mut c_void, 1024);
println!("module: {}", std::str::from_utf8_unchecked(&modname));
modname = [0;1024];
index += 1;
}
println!("Dump: {:?}", buffer.to_vec());
I saw that I had to use WaitForInputIdle() after using CreateProcessA before enumerating modules because the process doesn't have the time to "initialize", well when I do that, whatever the process I create (it successfully creates it) the program wait forever.
And when I try to do the same on the main process by replacing all the (*PI).hProcess by GetCurrentProcess() (I removed the WintForInputIdle() line), EnumProcessModules() still returns 0 but now GetLastError() returns 998 (ERROR_NOACCESS), but the modules handles are successfully written in buffer.
So the program output:
A:\Encrypted\Temp\injector\target\i686-pc-windows-msvc\debug\main.exe // (the program)
C:\WINDOWS\SYSTEM32\ntdll.dll
Dump: [0x920000, 0x77180000, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0]
And if I specify the path of the running program in CreateProcessA(), it will also return 0 with 299 as the windows error code.
I'm really confused...Thanks for reading, I hope I've been clear enough.

Answer 1

First, use the CREATE_NEW_CONSOLE or CREATE_NO_WINDOW instead of CREATE_SUSPENDED(0x00000004), as #Jonathan Potter, the suspend state will block the function WaitForInputIdle.
Second, make sure that the process is not a console application or has a message queue, otherwise WaitForInputIdle returns immediately.
Then, you can try to call SuspendThread after WaitForInputIdle to suspend the process to prevent it from ending.
EDIT:
Pay attention to the last two parameters of EnumProcessModules:
cb
The size of the lphModule array, in bytes.
lpcbNeeded
The number of bytes required to store all module handles in the
lphModule array.
Here is a good sample on msdn: Enumerating All Modules For a Process. Just replace hProcess.