Date: Thu, 25 Jul 2013 08:11:31 +0200 From: Hans Petter Selasky <hps@bitfrost.no> To: Damjan Jovanovic <damjan.jov@gmail.com> Cc: freebsd-usb@freebsd.org Subject: Re: COMPAT_32BIT libusb ABI problem Message-ID: <51F0C193.4000104@bitfrost.no> In-Reply-To: <CAJm2B-mfidBre0tCwJg=6OirBtdgvxCTrGGVX-3kqQ8vYf1kFw@mail.gmail.com> References: <CAJm2B-mfidBre0tCwJg=6OirBtdgvxCTrGGVX-3kqQ8vYf1kFw@mail.gmail.com>
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On 07/24/13 22:09, Damjan Jovanovic wrote:
> 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.
Hi,
How did you compile it? Is the structure the same size, compiled with
GCC and LLVM?
The LIB32 for USB has been tested. I did a quick test and found on 9-stable:
cc -m32 -I . -L /usr/lib32 -lusb usbconfig.c dump.c
env LD_PRELOAD=/usr/lib32/libusb.so ./a.out
ugen0.1: <UHCI root HUB Intel> at usbus0, cfg=0 md=HOST spd=FULL
(12Mbps) pwr=SAVE (0mA)
ugen1.1: <UHCI root HUB Intel> at usbus1, cfg=0 md=HOST spd=FULL
(12Mbps) pwr=SAVE (0mA)
...
Your approach requires much more code. It is not just about some
structures, but also about code accessing those structures. Feel free to
submit a patch however.
I would rather fix this by adding the proper __aligned() to the
structures in question.
--HPS
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