On a mounted VHD without a drive letter: error: unable to find zig self exe path: FileNotFound

[MarekKnapek]

Zig Version

0.12.0

Steps to Reproduce and Observed Behavior

• Windows x64
• Download the latest and greatest Zig version, 0.12.0
• Extract the zip archive to some directory
• Create test program in the same directory Zig was extracted into [1]
• Compile the test program: zig cc test.c

Actual Behavior:

error: unable to find zig self exe path: FileNotFound

[1]

int main(void)
{
	return 42;
}

Expected Behavior

No error message.

[squeek502]

Can't reproduce

C:\Users\Ryan\Programming\Zig\zig-windows-x86_64-0.12.0> zig cc test.c

C:\Users\Ryan\Programming\Zig\zig-windows-x86_64-0.12.0> a.exe

%errorlevel% 42

What filesystem are you using? Is there anything interesting about the path you're running from (non-ASCII characters, symbols, etc)?

[MarekKnapek]

Yes, the problem is in path. No spaces or non-ASCII letters present in it. But I have a *.VHD hard disk image mounted. Inside the hard disk there is a single NTFS partition / volume. This partition is mounted to a (host's) NTFS directory, not to a drive letter. When I add a drive letter to the partition, everything works correctly. But I don't want to, this way I would have multitude drive letters, I prefer having multitude mount directories instead.

[squeek502]

If you could give some instructions on how to recreate your setup that'd be helpful.

[MarekKnapek]

https://www.google.com/search?tbm=isch&q=disk+management+attach+vhd

[MarekKnapek]

[squeek502]

Mostly interested in how to do this:

This partition is mounted to a (host's) NTFS directory, not to a drive letter

EDIT: Nevermind, found the option in Disk Management's New Simple Wizard Volume (Mount in the following empty NTFS folder)

[MarekKnapek]

[squeek502]

Can reproduce now, thanks!

C:\Users\Ryan\Programming\Zig\tmp\vhd-mount\zig-windows-x86_64-0.12.0> zig cc test.c
error: unable to find zig self exe path: FileNotFound

[squeek502]

The error is coming from here in GetFinalPathNameByHandle:

zig/lib/std/os/windows.zig

Line 1377 in a7e4d17

return error.FileNotFound;

The final path gotten from QueryObjectName is \Device\HarddiskVolume10\test.exe for me. From a cursory look, it seems like we're only looking for mount points with drive letters, so we don't end up finding anything for \Device\HarddiskVolume10.

EDIT: The mount point symlink is \??\Volume{383da0b0-717f-41b6-8c36-00500992b58d}, we only look for the \DosDevices\ prefix.

[MarekKnapek]

Quick and dirty program written in C. seems to work correctly. Should be easy to port from C to Zig.

#include <assert.h> /* assert */
#include <stdio.h> /* wprintf */

#include <windows.h>


#define count(x) (sizeof(x) / sizeof((x)[0]))


int wmain(int argc, wchar_t** argv)
{
	if(argc != 2)
	{
		return __LINE__;
	}
	HANDLE file = CreateFileW(argv[1], FILE_GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_DELETE, NULL, OPEN_EXISTING, 0, NULL);
	if(file == INVALID_HANDLE_VALUE)
	{
		return __LINE__;
	}
	wchar_t path[1 * 1024]; /* max len is 64kB, thus 32k wchars */
	DWORD dw = GetFinalPathNameByHandleW(file, path, count(path), FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
	assert(dw != count(path));
	if(dw == 0 || dw > count(path))
	{
		return __LINE__;
	}
	wchar_t const* name;
	size_t len;
	if
	(
		dw >= 7 &&
		path[0] == L'\\' &&
		path[1] == L'\\' &&
		path[2] == L'?' &&
		path[3] == L'\\' &&
		((path[4] >= L'a' && path[4] <= L'z') || (path[4] >= L'A' && path[4] <= L'Z')) &&
		path[5] == L':' &&
		path[6] == L'\\'
	)
	{
		name = path + 4;
		len = dw - 4;
	}
	else
	{
		name = path;
		len = dw;
	}
	wprintf(L"Final Win32 name is: %s\n", name);
}

[squeek502]

Zig prefers NtDll implementations, see #1840.

I have a PR that should fix this problem, though: #19738

[MarekKnapek]

Thank you for speedy response. That is great. But wow, depending on NTAPI in general purpose tool (programming language) is ... bold.

[andrewrk]

Fix cherry-picked into 0.12.x branch as e36bf2b.