A wrapper executable to wrap Linux executable files on WSL to be callable from Windows.

wsl-wrapper.c

#define __STDC_WANT_LIB_EXT1__ 1
#include <stdio.h>
#include <stdlib.h>
#define _GNU_SOURCE
#include <string.h>

#if _WIN32 || _WIN64
#   define CDECL __cdecl
#   define WIN32_LEAN_AND_MEAN
#   include <windows.h>

#   define GET_CMD_LINE() GetCommandLine()

#   define EXEC_CMD(cmd) \
    do { \
        STARTUPINFO si = { 0 }; \
        PROCESS_INFORMATION pi = { 0 }; \
        if ( !CreateProcess( \
            NULL,     /* No module name (use command line) */ \
            (cmd),    /* Command line */ \
            NULL,     /* Process handle not inheritable */ \
            NULL,     /* Thread handle not inheritable */ \
            TRUE,    /* Set handle inheritance to TRUE */ \
            0,        /* No creation flags */ \
            NULL,     /* Use parent's environment block */ \
            NULL,     /* Use parent's starting directory */ \
            &si,      /* Pointer to STARTUPINFO structure */ \
            &pi )     /* Pointer to PROCESS_INFORMATION structure */ \
        ) \
        { \
            fprintf(stderr, "CreateProcess failed (%d).\n", GetLastError() ); \
            return EXIT_FAILURE; \
        } \
        /* Wait until child process exits. */ \
        WaitForSingleObject( pi.hProcess, INFINITE ); \
        CloseHandle( pi.hProcess ); /* Close process and thread handles. */ \
        CloseHandle( pi.hThread ); \
    } while (0)
#else
#   include <unistd.h>
#   include <libgen.h>
#   define CDECL
#endif

#ifdef _MSC_VER
#   define __STDC_LIB_EXT1__ 1
#endif

#ifndef _countof
#   define _countof(array) (sizeof(array) / sizeof(array[0]))
#endif

#ifndef _MAX_ARG
#   define _MAX_ARG 0x8000
#endif

#ifndef _MAX_FNAME
#   define _MAX_FNAME 256
#endif

#if __STDC_LIB_EXT1__
#   define STRCAT(p, s) strcat_s((p), _countof((p)), (s))
#   define FILENAME(p, f) _splitpath_s((p), NULL, 0, NULL, 0, (f), _countof((f)), NULL, 0)
#else
#   define STRCAT(p, s) strcat(p, s)
#   define FILENAME(p, f) _splitpath((p), NULL, NULL, (f), NULL)
#endif

int
CDECL main(int argc, char *argv[])
{
#ifdef GET_CMD_LINE
    char wslArgs[_MAX_ARG] = { 0 };
    char fname[_MAX_FNAME] = { 0 };
    char *cmdLine;
    char *spaceOrQuote;
    int spaceOrQuoteIdx;

    cmdLine = GET_CMD_LINE();
    if (strchr(argv[0], ' '))
    {
        if (spaceOrQuote = strchr(strchr(cmdLine, ' '), '"'))
        {
            spaceOrQuoteIdx = (spaceOrQuote - cmdLine) + 1;
        }
        else
        {
            fprintf(stderr, "%s is not properly escaped!\n", argv[0]);
            return EXIT_FAILURE;
        }
    }
    else
    {
        spaceOrQuoteIdx = strlen(argv[0]);
    }
    FILENAME(argv[0], fname);

    STRCAT(wslArgs, "wsl.exe \"");
    STRCAT(wslArgs, fname);
    STRCAT(wslArgs, "\" ");
    STRCAT(wslArgs, cmdLine + spaceOrQuoteIdx);

    EXEC_CMD(wslArgs);
#else
    char *cargv[argc + 1];

    cargv[0] = basename(argv[0]);

    for (int i = 1; i < argc; i++)
    {
        cargv[i] = argv[i];
    }
    cargv[argc] = NULL;

    /* basically just pass through all arguments and use the executable
       in the path. So `./cp' will turn into `cp' and thus `/bin/cp' */
    execvp(cargv[0], cargv);
#endif
}