How to access files from the binary

[coolcoder613eb]

I have built RustPython for DOS, https://github.com/coolcoder613eb/RustPython
And I want to know how make the binary accept files from the command line.
right now it says:

[ERROR rustpython_vm::vm::compile] Failed reading file 'PYBASIC.PY': No such file or directory (os error 44)

[turbolent]

Are you sure you are providing the WASI environment with a file descriptor (capability) to the directory? See e.g.

w2c2/examples/python/main.c

Lines 211 to 214 in 2e9c86f

	if (!wasiFileDescriptorAdd(-1, "/", NULL)) {
	fprintf(stderr, "failed to add preopen\n");
	return 1;
	}

Note that paths are assumed to be WASI paths, which are Unix/POSIX paths (e.g /foo/bar).

w2c2's WASI implementation automatically translates Unix paths to the native format (

w2c2/wasi/wasi.c

Lines 313 to 333 in 2e9c86f

	#elif defined(__MSDOS__)
	bool isAbsolute = path[0] == '/';
	char *pos = path;
	while ((pos = strchr(pos, '/'))) {
	*pos = PATH_SEPARATOR;
	}
	/* Prefix with volume name */
	if (isAbsolute) {
	size_t pathLength = strlen(path);
	unsigned int drive;
	_dos_getdrive(&drive);
	memmove(path + 2, path, pathLength);
	path[0] = 'A' + drive - 1;
	path[1] = ':';
	pathLength += 2;
	path[pathLength] = '\0';
	}
	#else

), and back

What compiler are you using, DJGPP?

[coolcoder613eb]

Yes, DJGPP, and i think i have fixed it, my solution also means you do not need to write out the full path.
my code in main.c:

#ifdef __MSDOS__
    if (!wasiFileDescriptorAdd(-1, "C:\\", NULL)) {
        fprintf(stderr, "failed to add preopen\n");
        return 1;
    }
#endif
    if (!wasiFileDescriptorAdd(-2, ".", NULL)) {
        fprintf(stderr, "failed to add preopen\n");
        return 1;
    }

    if (!wasiFileDescriptorAdd(-3, "/", NULL)) {
        fprintf(stderr, "failed to add preopen\n");
        return 1;
    }

[coolcoder613eb]

Not really related, but how would I compile for windows 2000?
CPython3.11, and RustPython without freeze-stdlib, don't work on DOS through w2c2 because of 8.3, is there any solution?

[SamuraiCrow]

How do you run on drive D or later with your fix?

[coolcoder613eb]

I dont know, haven't tried.
I could try doing:

if (!wasiFileDescriptorAdd(-1, "A:\\", NULL)) {
        fprintf(stderr, "failed to add A: preopen\n");
    }
if (!wasiFileDescriptorAdd(-1, "B:\\", NULL)) {
        fprintf(stderr, "failed to add B: preopen\n");
    }
if (!wasiFileDescriptorAdd(-1, "C:\\", NULL)) {
        fprintf(stderr, "failed to add C: preopen\n");
    }
if (!wasiFileDescriptorAdd(-1, "D:\\", NULL)) {
        fprintf(stderr, "failed to add D: preopen\n");
    }

etc