pipe_inspect.cpp

#include <wtypes.h>
#include <errno.h>
#include <fcntl.h>
#include <io.h>
#include <windows.h>
#include <winternl.h>
#include <process.h>
#include <iostream>

typedef enum {
    FileModeInformation = 16,
    FilePipeLocalInformation = 24,
} MY_FILE_INFORMATION_CLASS;

typedef NTSTATUS(NTAPI* _NtQueryInformationFile_fn)(
    HANDLE FileHandle, PIO_STATUS_BLOCK IoStatusBlock, PVOID FileInformation,
    ULONG Length, MY_FILE_INFORMATION_CLASS FileInformationClass);

static _NtQueryInformationFile_fn pNtQueryInformationFile;

typedef struct _FILE_MODE_INFORMATION {
    ULONG Mode;
} FILE_MODE_INFORMATION, * PFILE_MODE_INFORMATION;

typedef struct _FILE_PIPE_LOCAL_INFORMATION {
    ULONG NamedPipeType;
    ULONG NamedPipeConfiguration;
    ULONG MaximumInstances;
    ULONG CurrentInstances;
    ULONG InboundQuota;
    ULONG ReadDataAvailable;
    ULONG OutboundQuota;
    ULONG WriteQuotaAvailable;
    ULONG NamedPipeState;
    ULONG NamedPipeEnd;
} FILE_PIPE_LOCAL_INFORMATION, * PFILE_PIPE_LOCAL_INFORMATION;

namespace {
DWORD inspect_pipe(const HANDLE& hPipe) {
    static std::once_flag once_flag;
    std::call_once(once_flag, []() {
        HMODULE ntdll = LoadLibraryW(L"ntdll.dll");
        // Not found.
        if (!ntdll) return;

        // Lookup 'NtQueryInformationFile' from ntdll.dll. This should be included
        // in Windows 2000 and newer. NOTE: Not an official API, so its parameters
        // are may change in a future release. However, this has been stable for
        // years at this point and is used by multiple libraries and runtimes.
        pNtQueryInformationFile = (_NtQueryInformationFile_fn)GetProcAddress(
            ntdll, "NtQueryInformationFile");
        });

    NTSTATUS nt_status;
    IO_STATUS_BLOCK io_status;
    FILE_MODE_INFORMATION mode_info;

    pNtQueryInformationFile(hPipe, &io_status, &mode_info, sizeof(mode_info), FileModeInformation);

    std::cout << "pipe mode: " << mode_info.Mode << std::endl;

    FILE_PIPE_LOCAL_INFORMATION pipe_info;
    pNtQueryInformationFile(hPipe, &io_status, &pipe_info, sizeof(pipe_info), FilePipeLocalInformation);

    std::cout << "pipe info: " << pipe_info.NamedPipeType << std::endl;

    return 0;
}
}

int main()
{
    HANDLE hStdIn = (HANDLE)_get_osfhandle(_fileno(stdin));
    if (GetFileType(hStdIn) == FILE_TYPE_PIPE)
        inspect_pipe(hStdIn);
    else
        std::cout << "not a pipe\n";
    return 0;
}