Date: Mon, 29 Oct 2001 13:43:53 -0800 (PST) From: John Baldwin <jhb@FreeBSD.org> To: Julian Elischer <julian@elischer.org> Cc: arch@FreeBSD.ORG, Jake Burkholder <jake@locore.ca> Subject: Re: syscall() ABI questions Message-ID: <XFMail.011029134353.jhb@FreeBSD.org> In-Reply-To: <Pine.BSF.4.21.0110291255300.26174-100000@InterJet.elischer.org>
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On 29-Oct-01 Julian Elischer wrote: > But the API for vfork forbids the child from doing a 'ret' after the vfork > returns.. if it does that, all bets are off.... you can do: > vfork(); > exec(); > > and that 's about all that's ok... > I'm not even sure about > vfork(); > exit(); Jake is talking about the return from the actual vfork() wrapper in libc for the syscall. We have to return from that. :) So we do that by saving the return address in a register and adjusting the stack before return in case the child clobbers that part of the stack we can restore it for the parent. -- John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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