COMPAT_32BIT libusb ABI problem

[Damjan Jovanovic]

Hi

The ioctl:
#define USB_FS_INIT             _IOW ('U', 195, struct usb_fs_init)
when used by a COMPAT_32BIT libusb on amd64, fails (causing
libusb_open() to fail) due to:

freebsd32_ioctl(0x6,0x800c55c3,0xffffc710,0x0,0x0,0x0) ERR#25
'Inappropriate ioctl for device'
but when hacked a bit:
freebsd32_ioctl(0x6,0x801055c3,0xffffc710,0x0,0x0,0x0) = 0 (0x0)

because sizeof(struct usb_fs_init) is 12 bytes on i386, and 16 bytes on amd64.

But the failure of even libusb_open() - a fundamental libusb function
- must mean that the COMPAT_32BIT libusb never worked. Can we please
take this opportunity to kill it and do a real 32 bit compatibility
layer in the kernel that will work from 32 bit chroots and statically
linked 32 bit binaries? I'll help.

Regards
Damjan