Gentoo Archives: gentoo-user

From: nunojsilva@ist.utl.pt (Nuno J. Silva)
To: Volker Armin Hemmann <volkerarmin@××××××××××.com>
Cc: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Re: Anyone switched to eudev yet?
Date: Thu, 27 Dec 2012 20:13:13
Message-Id: 87zk0z1ccu.fsf@ist.utl.pt
In Reply to: Re: [gentoo-user] Re: Anyone switched to eudev yet? by Volker Armin Hemmann
1 On 2012-12-27, Volker Armin Hemmann wrote:
2
3 > Am Sonntag, 23. Dezember 2012, 19:44:43 schrieb Nuno J. Silva:
4 >> On 2012-12-23, Alan Mackenzie wrote:
5 >> > On Sun, Dec 23, 2012 at 07:03:25PM +0200, Nuno J. Silva wrote:
6 >> >> On 2012-12-23, Alan McKinnon wrote:
7 >> >> > On Sun, 23 Dec 2012 12:22:24 +0200
8 >> >> >
9 >> >> > nunojsilva@×××××××.pt (Nuno J. Silva) wrote:
10 >> >> >> On 2012-12-18, Alan McKinnon wrote:
11 >> >> >> > On Tue, 18 Dec 2012 09:08:53 -0500
12 >> >> >> > Michael Mol <mikemol@×××××.com> wrote:
13 >> >> >> >
14 >> >> >> > This sentence summarizes my understanding of your post nicely:
15 >> >> >> >> Now, why is /usr special? It's because it contains executable code
16 >> >> >> >> the system might require while launching.
17 >> >> >> >
18 >> >> >> > Now there are only two approaches that could solve that problem:
19 >> >> >> >
20 >> >> >> > 1. Avoid it entirely
21 >> >> >> > 2. Deal with it using any of a variety of bootstrap techniques
22 >> >> >> >
23 >> >> >> > #1 is handled by policy, whereby any code the system might require
24 >> >> >> > while launching is not in /usr.
25 >> >> >> >
26 >> >> >> > #2 already has a solution, it's called an init*. Other solutions
27 >> >> >> > exist but none are as elegant as a throwaway temporary filesystem
28 >> >> >> > in RAM.
29 >> >> >>
30 >> >> >> What about just mounting /usr as soon as the system boots?
31 >> >> >
32 >> >> > Please read the thread next time. The topic under discussion is
33 >> >> > solutions to the problem of not being able to do exactly that.
34 >> >>
35 >> >> Then I suppose you can surely explain in a nutshell why can't init
36 >> >> scripts simply do that?
37 >> >
38 >> > Because certain people with influence have rearranged the filesystem so
39 >> > that programs within /usr are absolutely necessary for booting; they are
40 >> > needed _before_ init has a chance to mount /usr. So either /usr has to
41 >> > be in the root partition, or crazy kludges need to be used to mount /usr
42 >> > before the kernel runs init.
43 >>
44 >> I surely don't know the udev architecture well enough, but if this is
45 >> all done by the udev daemon, can't we just "mount /usr" before the
46 >> daemon is started? The only needed things should be mount (which is
47 >> under /bin here) and /etc/fstab.
48 >>
49 >
50 > and a device node in /dev - like /dev/sda2. And how do you get that one
51 > without udev?
52 >
53 > oops?
54
55 Please try booting your system and getting to a shell before udevd gets
56 started.
57
58 Then, please do ls /dev.
59
60 --
61 Nuno Silva (aka njsg)
62 http://njsg.sdf-eu.org/