Date: Sun, 25 May 2003 20:33:31 -0400 (EDT) From: "Matthew N. Dodd" <mdodd@FreeBSD.ORG> To: Marcel Moolenaar <marcel@xcllnt.net> Cc: current@FreeBSD.ORG Subject: Re: Preliminary ELF prebinding patches available. Message-ID: <20030525202140.Y86964@sasami.jurai.net> In-Reply-To: <20030526001924.GA1272@athlon.pn.xcllnt.net> References: <20030525061524.H30007@sasami.jurai.net> <xzpaddb8ab8.fsf@flood.ping.uio.no> <20030525222955.GA826@athlon.pn.xcllnt.net> <20030526001924.GA1272@athlon.pn.xcllnt.net>
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On Sun, 25 May 2003, Marcel Moolenaar wrote: > > I was more concerned with simplicity; the method I use solves the problem > > with minimal effort and complexity. The combination of time() + random() > > + filename will not collide on a single box. > > But it can across NFS, right? Uh... If you want to share /var/db/prebind via NFS I suppose you can. I'm not sure how a practical NFS environment would result in a greater chance of collisions. Regardless, there is no real penalty for collisions (other than prebinding not being available for that executable.) > > I'll be adding a platform identifier to the file header. All I'm > > concerned with is being able to reject a file if its not for the current > > platform. I have no expectation of cross-generating prebinding files. > > Please keep that option open. Not only do we have to deal with byte- > order on a single platform, we also have to keep an eye on emulation > layers (ia32 on ia64 and ia32 on amd64). Its simply not possible to cross-generate prebinding files. Period. (You're of course welcome to implement a totally standalone utility that duplicates much of the functionality that rtld-elf provides.) > Decoupling the program from its prebinding information can create all > sorts of nasty (ie unexpected) complexities. Uh, what? I'm not parsing this. > What are the major reasons for not editing the executable in your > opinion? Besides it not working? It is not possible for rtld-elf to access the section header, let alone additional section data in a clean manner. Furthermore, rtld-elf is not provided with a valid file handle for the main executable so hacks to access section data of libraries won't actually work for the main executable. I ran around in circles until I'd figured all this out. -- | Matthew N. Dodd | '78 Datsun 280Z | '75 Volvo 164E | FreeBSD/NetBSD | | winter@jurai.net | 2 x '84 Volvo 245DL | ix86,sparc,pmax | | http://www.jurai.net/~winter | For Great Justice! | ISO8802.5 4ever |
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