[Toybox] non-GPLv3 mtools?

[Rob Landley]

On 03/14/2016 10:36 PM, enh wrote:
> a non-GPLv3 mtools would be nice for UEFI purposes.

That's on my todo list, and actually not that hard. I could bump it up,
it was just post 1.0 because it's not in any of the priority roadmap
categories. (Build tools, posix, lsb, existing android.)

> (actually, better than mtools would be "take this directory and give
> me a corresponding FAT[1] image".)

Yes. A genfatfs ala genext2fs. (Well, vfat with windows 95 long filenames.)

> i don't know how many requests you need before you put things on the
> roadmap, but afaik there's no non-GPLv3 alternative here, which seems
> like a good niche for someone to fill...

Putting stuff on the roadmap is easy. Moving stuff to the top of the
todo list is harder. :)

That said, part of the reason I did dirtree was so I could scan all the
directory metadata ahead of time, so I could make it work like an archiver.

Basically every mkXXXfs command toybox has should also have a genXXXfs
version, and I want it so you can stream the output.

I can "tar cz dirname | ssh blah tar xvz" which doesn't work if you have
to mmap the file to write to it.) I ran into the fact that the ext2
superblock has total used/free block counts, and then the inode and
block allocation tables come before the file data, so in order to write
it out in sequence I had to read ahead at least all the file metadata
for the entire filesystem before writing the first block. And I didn't
have a thing that could do that, so I mothballed it until I wrote one...

I should get back to that. :)

> ___
> 1. okay, not really FAT ("The file system supported by the Extensible
> Firmware Interface is based on the FAT file system. EFI defines a
> specific version of FAT that is explicitly documented and testable.
> Conformance to the EFI specification and its associate reference
> documents is the only definition of FAT that needs to be implemented
> to support EFI. To differentiate the EFI file system from pure FAT, a
> new partition file system type has been defined.") but FAT-ish.

I dunno about fat-ish but I've done some research on the topic. I was
more or less looking at Linux's vfat. (I can probably ignore fat12 but
fat16 still exists, and fat32 is probably the standard now?)

I also poked a bit at qemu's "create a fat volume from this directory"
mode a few years ago.

Do you have a reference to the EFI fat spec?

Rob

 1458018357.0