Date: Mon, 24 Oct 2011 07:42:10 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-amd64@freebsd.org Cc: freebsd-emulation@freebsd.org Subject: Re: 32-bit binaries (e.g. wine) and 64-bit kernel structures Message-ID: <201110240742.10896.jhb@freebsd.org> In-Reply-To: <CAAMzD71D%2B%2Bq_XjuCe=is2SAsW843_TNYmxaFOcjM4-%2BQ-jRrzg@mail.gmail.com> References: <CAAMzD71D%2B%2Bq_XjuCe=is2SAsW843_TNYmxaFOcjM4-%2BQ-jRrzg@mail.gmail.com>
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On Sunday, October 23, 2011 7:04:51 pm Li-Lun "Leland" Wang wrote: > Hi, > > Although I only encounter this kind of problem when running wine > (because it is one of the few ports that need to compile into 32-bit), > it is a problem of i386 binaries on x64 FreeBSD in general. > > The problem that I'm running into recently is > http://bugs.winehq.org/show_bug.cgi?id=28857 . > In short, wine recently implemented GetUdpTable() for Mac OS and BSD. > It uses sysctlbyname() to get net.inet.udp.pcblist, and parses it into > xinpgen structures. However, the size of xinpgen is different on i386 > and x64. As a result, when I run applications that call > GetUdpTable(), the kernel supplies wine with 64-bit structures, while > wine expects 32-bit structures, and crashes. They decided that this > is a FreeBSD bug rather than a wine bug, and that the kernel or LD > should know a 32-bit binary is being run and return proper structures, > as is done in Mac OS. > > xinpgen is not the only structure of wrong sizes for 32-bit binaries > on x64. A while ago I was trying to make my usb gamepad work on wine > using the ugen device. libusbhid uses ioctl to get the > usb_gen_descriptor structure, which is also of different sizes on i386 > and x64. I had to manually "pad" the pointers to 64-bit and build a > custom libusbhid for it to work. > > As it stands, they will probably not fix GetUdpTable() on wine side, > and any windows applications that uses GetUdpTable() will not run > properly in wine on FreeBSD x64. Do we have plans to fix this kind of > problems in general? Although wine port on FreeBSD is only supported > for ARCH=i386, could there be workarounds? Fixing this problem generically is very hard. Instead, we have patched individual sysctls and ioctls on a case-by-case basis. I do think newer interfaces often opt to use fixed-size types so that the structure is the same for both 32-bit and 64-bit, but that will not work for existing interfaces. -- John Baldwin
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