Date: Thu, 15 Mar 2012 16:56:14 -0600 From: Ian Lepore <freebsd@damnhippie.dyndns.org> To: Ed Schouten <ed@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org Subject: Re: svn commit: r232977 - in head: etc sbin/init Message-ID: <1331852174.8403.12.camel@revolution.hippie.lan> In-Reply-To: <201203141622.q2EGM9HR021407@svn.freebsd.org> References: <201203141622.q2EGM9HR021407@svn.freebsd.org>
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On Wed, 2012-03-14 at 16:22 +0000, Ed Schouten wrote: > Author: ed > Date: Wed Mar 14 16:22:09 2012 > New Revision: 232977 > URL: http://svn.freebsd.org/changeset/base/232977 > > Log: > Make init(8) slightly more robust when /dev/console is missing. > > If the environment doesn't offer a working /dev/console, the existing > version of init(8) will simply refuse running rc(8) scripts. This means > you'll only have a system running init(8) and nothing else. > > Change the code to do the following: > > - Open /dev/console like we used to do, but make it more robust to use > O_NONBLOCK to prevent blocking on a carrier. > - If this fails, use /dev/null as stdin and /var/log/init.log as stdout > and stderr. Given that the /var filesystem is mounted (and with readonly root, actually created) by an rc script run by init, does this make sense? Maybe it makes sense only within a jail, but not when running as pid 1? > - If even this fails, use /dev/null as stdin, stdout and stderr. > > So why us this useful? Well, if you remove the `getpid() == 1' check in > main(), you can now use init(8) inside jails to properly execute rc(8). > It still requires some polishing, as existing tools assume init(8) has > PID 1. Not just existing tools, but 3rd party software is likely to contain this assumption (I know some of ours does). The manpage for init contains examples of using a hard-coded 1. Would it be practical for any reference to pid 1 to get somehow magically redirected inside a jail to the pid of an init process running within that jail? That's just a pure blue-sky idea that popped into my head; I know almost nothing about jails (their implementation or how to use them). > > Also it is now possible to use use init(8) on `headless' devices that > don't even have a serial boot console. -- Ian
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