ntqueryvolumeinformation.c

#include <unistd.h>
#include <stdio.h>
#include <stdbool.h>
#include <fcntl.h>
#include <io.h>

#include <windows.h>
#include <winternl.h>

#ifndef FILE_REMOTE_DEVICE
#define FILE_REMOTE_DEVICE (0x10)
#endif

static NTSTATUS (NTAPI *pNtQueryVolumeInformationFile)(HANDLE,
	PIO_STATUS_BLOCK, PVOID, ULONG, FS_INFORMATION_CLASS);

static void load_functions(void)
{
	HMODULE ntdll = GetModuleHandleW(L"ntdll.dll");

	pNtQueryVolumeInformationFile = (NTSTATUS (NTAPI*)(HANDLE,
		PIO_STATUS_BLOCK, PVOID, ULONG, FS_INFORMATION_CLASS))
		GetProcAddress(ntdll, "NtQueryVolumeInformationFile");
}

static bool is_network_file(int fd)
{
	if (!pNtQueryVolumeInformationFile)
		return false;

	HANDLE h = (HANDLE)_get_osfhandle(fd);

	FILE_FS_DEVICE_INFORMATION info;
	IO_STATUS_BLOCK io;
	NTSTATUS status = pNtQueryVolumeInformationFile(h, &io, &info,
		sizeof(info), FileFsDeviceInformation);
	if (status)
		return false;

	return info.DeviceType == FILE_DEVICE_NETWORK_FILE_SYSTEM ||
	       (info.Characteristics & FILE_REMOTE_DEVICE);
}

int main(int argc, char **argv)
{
	load_functions();

	if (!argv[1]) {
		fprintf(stderr, "usage: %s path\n", argv[0]);
		return 1;
	}

	int fd = open(argv[1], O_RDONLY | O_BINARY);
	if (fd < 0) {
		perror(argv[1]);
		return 2;
	}

	if (is_network_file(fd))
		puts("network file");
	else
		puts("local file");

	close(fd);
	return 0;
}