Date: Thu, 7 Jun 2012 11:16:33 -0400 From: John Baldwin <jhb@freebsd.org> To: rank1seeker@gmail.com Cc: hackers@freebsd.org Subject: Re: CD bootcode Message-ID: <201206071116.33215.jhb@freebsd.org> In-Reply-To: <20120607.135825.592.1@DOMY-PC> References: <20120606.161514.685.1@DOMY-PC> <201206070821.40068.jhb@freebsd.org> <20120607.135825.592.1@DOMY-PC>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thursday, June 07, 2012 9:58:25 am rank1seeker@gmail.com wrote: > ----- Original Message ----- > From: John Baldwin <jhb@freebsd.org> > To: freebsd-hackers@freebsd.org > Cc: rank1seeker@gmail.com > Date: Thu, 7 Jun 2012 08:21:39 -0400 > Subject: Re: CD bootcode > > > On Wednesday, June 06, 2012 12:15:14 pm rank1seeker@gmail.com wrote: > > > FreeBSD's CD bootcode '/boot/cdboot' is targeting stage 3 boot -> loader > > > For example, stage 2 boot '/boot/boot' is attempting the same. > > > > > > In my case of a '/boot/loader', '/boot' is a symlink! > > > > > > So if '/boot/boot' works with symlinks, why '/boot/cdboot' doesn't! > > > Yes, I did use Rock-Ridge extensions, upon creation of 'cd.iso' > > > > Because I didn't make cdboot's lookup routine handle symlinks. It > > also doesn't look at Rock-Ridge extensions and only uses the base > > ISO-9660 directory entries. That was enough fun to write in assembly. > > OTOH, CD sectors are 2k, so you do have that much room to work with > > and can probably fit a more advanced directory lookup into cdboot. > > > > I'm happy to review any patches you come up with. > > > > -- > > John Baldwin > > > I need to correct myself. > BOTH stage 2 boot '/boot/boot' AND '/boot/cdboot' don't work with symlinks! Correct. > '/boot/boot' on UFS sees symlink as file, same as '/boot/cdboot' does so on Rock-Ridge. > > I can handle '/boot/boot' by providing full path to loader via 'boot.config' > '/boot/cdboot' doesn't have such a file, so in '/usr/src/sys/boot/i386/cdboot/cdboot.s': > -- > loader_paths: .asciz "/BOOT/LOADER" > .asciz "/boot/loader" > .byte 0 > -- > > I injected third '.asciz' line with full path to 'loader' and recompiled it. > And what is first line "/BOOT/LOADER" doing in there ?!? Plain ISO-9660 always uses uppercase letters for filenames. There is a mkisofs flag to use lowercase, but by default it uppercases all filenames. > But even when loader is finally started, loader handles symlinks on UFS (kicked by '/boot/boot'), BUT fails so, on Rock-Ridge iso (kicked by '/boot/cdboot') > Looks like loader must be made into looking at Rock-Ridge extensions. It is src/lib/libstand/cd9660.c that would have to be patched. It already has limited Rock-Ridge support, so adding symlink support to cd9660_open() may not be that hard to do. -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201206071116.33215.jhb>