From owner-freebsd-stable@FreeBSD.ORG Mon Jun 24 23:34:50 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 43BF4621 for ; Mon, 24 Jun 2013 23:34:50 +0000 (UTC) (envelope-from artemb@gmail.com) Received: from mail-ve0-x22c.google.com (mail-ve0-x22c.google.com [IPv6:2607:f8b0:400c:c01::22c]) by mx1.freebsd.org (Postfix) with ESMTP id 0786816C7 for ; Mon, 24 Jun 2013 23:34:49 +0000 (UTC) Received: by mail-ve0-f172.google.com with SMTP id jz10so9443473veb.31 for ; Mon, 24 Jun 2013 16:34:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=kluAgbOWoAGM72V067D2klqvYMcOW+42mScjWYdg6BI=; b=rJsW1lXAUgDjMt4cfQ9y64N9gsvxmgiN/k0uBWk9+gA+oL6hnfr6f/wtObTOph/k1z Bzn0K8agLkKc3c4JODs/RrGCoQcwIj1Cihx4XEQJzuyNJQeDIih5/e9VWQtSSv7Om5/f 8M2DpjvHDjt82tIrMJ/AcMY5rpV02ZjMaTPqWerS1X9tayTRqp57XDqRmtPn6daEM6yc YLRo/MbnswFNBN2SXpwhNj5/4w8++jbRcT+zvtm56KOKQxg7pGI7SNa057oJ6rGRQ8UH LmWfnOMpLbIbUfo9T4caFYzEJBiMnfONZ2aEdaqL2BapHT2WwoyZ/Gnt32Vxe5tLuvt6 ogVw== MIME-Version: 1.0 X-Received: by 10.52.29.241 with SMTP id n17mr10686185vdh.95.1372116889526; Mon, 24 Jun 2013 16:34:49 -0700 (PDT) Sender: artemb@gmail.com Received: by 10.221.41.6 with HTTP; Mon, 24 Jun 2013 16:34:49 -0700 (PDT) In-Reply-To: <51BDEF40.4060001@andyit.com.au> References: <51BDEF40.4060001@andyit.com.au> Date: Mon, 24 Jun 2013 16:34:49 -0700 X-Google-Sender-Auth: qqzNt39MOT-FZml2rjNT_TG9PDE Message-ID: Subject: Re: FreeBSD history From: Artem Belevich To: Andy Farkas Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: jdc@koitsu.org, freebsd-stable X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 24 Jun 2013 23:34:50 -0000 On Sun, Jun 16, 2013 at 10:00 AM, Andy Farkas wrote: > On 16/06/13 20:30, Jeremy Chadwick wrote: > > * Output from: strings /boot/kernel/kernel | egrep ^option Thanks. > > I stumbled across this one about a week ago: > > strings /boot/kernel/kernel | head -1 > > and was wondering about the history of where it came from / what it means. > > I can see it was added to Makefile.i386 in September 1998 but the commit > comment mentions the defunct alpha port and searching SVN for things in the > Attic is a PITA. > The key in the log message is that the kernel became a dynamic executable. In order to launch typical dynamic executable kernel would actually launch dynamic linker specified in the INTERP program header in the ELF file. By default it's /libexec/ld-elf.so.1. Dynamic linker in turn would load the app and the shared libraries it requires. Kernel is, obviously, not a typical executable. My guess is that the idea behind changing dynamic linker to /red/herring was to make it obvious that the file is not a typical app and that despite being an ELF executable, it should not be executed as a regular program. It's just a guess, though. --Artem