Trim colon from device names

[andrewbird]

So this trims a trailing colon from file names that may be a device, BUT I don't like that if you pass it a name + : that isn't a device it has the potential to overwrite some other file.

e.g.

echo longstring > nul:  # does what we want
echo astring > c:      # same behaviour as now
echo anotherstring > cx:  # creates or overwrites a file called 'cx'

Short of doing 'is_device_name()' on the filename, I don't know how to make this safe?

[stsp]

Just a quick suggestion
to weight in: you can try
findfirst_f() on it, then
looking at ff.ff_attrib == _A_DEVICE -
see perform_dir() as
an example.

[andrewbird]

I looked at find first as you suggested, but didn't see how I could 'find' a device without it existing on the filesystem. I admit I didn't actually try it so it might have worked just fine.

I ended up just trying to open it readonly and if successful I could use https://fd.lod.bz/rbil/interrup/dos_kernel/214400.html#2860 to determine if it was a device or not.

I'll need to test thoroughly...

[stsp]

But how perform_dir() works?
I was hoping that all devices
pretend to "exist" on mfs level.

[andrewbird]

But how perform_dir() works?

Yes, I'll modify to use findfirst(). I think what put me off was the thought that it was scanning a directory looking for a match, but if the target is explicit perhaps it does something special.

Also I just checked what MS-DOS 6.22 (& OPENDOS 7.01) does with echo longstring > cx:, it creates a file called 'cx'. This is nasty, I'm torn now between what we have now (creating an LFN called cx:), what I'd like (throwing some error) or adopting that behaviour (create SFN called cx)?

FreeCOM does this

Can not redirect output to file 'cx:'.