Date: Sat, 26 Sep 2015 18:08:26 -0300 From: Mario Lobo <lobo@bsd.com.br> To: Alexander Leidinger <Alexander@leidinger.net> Cc: freebsd-emulation@freebsd.org Subject: Re: /dev for Linux binaries in freebsd Message-ID: <20150926180826.5d673a64@Papi> In-Reply-To: <20150926134433.Horde.dywx79dLiTk9Z_UmyvgIU7-@webmail.leidinger.net> References: <20150924195443.1805e50d@Papi> <20150926134433.Horde.dywx79dLiTk9Z_UmyvgIU7-@webmail.leidinger.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, 26 Sep 2015 13:44:33 +0200 Alexander Leidinger <Alexander@leidinger.net> wrote: > Quoting Mario Lobo <lobo@bsd.com.br> (from Thu, 24 Sep 2015 19:54:43 > -0300): > > > I was trying to find out where a linux binary will look for the /dev > > directory. > > > > I tried to link the device I need to /compat/linux/dev but that > > didn't work. > > This is expected. Do not create links to the real /dev there, you > will create a loop (see below). > > > How can a linux binary see the devices (serial ports, usb, etc) of > > the system? > > The behavior under the assumption that you haven't chrooted into > /compat/linux is: > > A linux program will ask the kernel for /dev/xyz. > The kernel knows that it is a linux program, and as such it will > first look for /compat/linux/dev/xyz. > If the kernel doesn't find the device there, it will look > for /dev/xyz. > > As such you should not touch /compat/linux/dev at all, it will > "fall-through" to the real /dev. > > Maybe your real problem is not that you can't access the right /dev/ > entry, but that the devide doesn't understand what the linux program > wants to do. > > You can use ktrace or dtrace to check what the program tries to do. > You should see in the output what the real patch is it tries to > reach and what kind or errno it get's when it tries to access it. > > > If you chroot into /compat/linux, you need to mount devfs in > additionally to /compat/linux/dev. > > Bye, > Alexander. Thanks for the tips, Alexander. I`ll see what I can find out. -- Mario Lobo http://www.mallavoodoo.com.br FreeBSD since 2.2.8 [not Pro-Audio.... YET!!] "UNIX was not designed to stop you from doing stupid things, because that would also stop you from doing clever things."
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20150926180826.5d673a64>