Gentoo Archives: gentoo-embedded

From: "P. Levine" <plevine457@×××××××.net>
To: gentoo-embedded@l.g.o
Subject: Re: [gentoo-embedded] emerge --root : users not created
Date: Tue, 16 Feb 2010 16:06:32
Message-Id: 4B7ABCD4.4070805@verizon.net
1 On 02/16/2010 10:04 AM, P. Levine wrote:
2 > Peter Stuge wrote:
3 >> I talked to upstream on freenode/#shadow and they welcome a patch for
4 >> adding --chroot
5 >>
6 >> chroot() needs to happen really early since useradd and friends read
7 >> some configuration files to know e.g. which password encryption
8 >> method to use.
9 >
10 > Attached is a tentative patch to add a chroot flag to useradd and
11 > groupadd (via --chroot or -R). It compiles and works on my end
12 > (--chroot /usr/armv4tl-softfloat-linux-gnueabi) with various other flags
13 > enabled. I'm hoping for others to test it and get some feedback before
14 > I submit it to shadow upstream.
15 >
16 > There do exist a couple of issues:
17 >
18 > sysconf(_SC_NGROUPS_MAX) is called by useradd early on. This would
19 > report the maximum allowable number of groups per user on the build
20 > system, not the target. To my knowledge, this is set by the kernel and
21 > would have to be used. However, this tends to be a very high number for
22 > linux kernel >= 2.6.3 (65536) so it seems like a mute point (for linux
23 > kernel >= 2.6.3).
24 >
25 > There are a number of calls to "getXXbyYY" functions (i.e., getgrgid,
26 > getpwnam, etc...). These seem to be dynamically preloaded and access
27 > preloaded databases. They are unaffected by chroot() (even after
28 > setting __nss_configure_lookup(foo, files)). I've instead used shadow's
29 > own method of macro expansion to generate functions doing the
30 > equivalent, with recursive calls to fgetXXent functions.
31 >
32 > And PAM functionality doesn't work and has to be disabled while using
33 > chroot(). I don't know very much about PAM. Would this be a problem?
34 >
35 > Also, the chroot functionality could probably be easily extended to
36 > other modules but I'm not sure if this would be acceptable upstream.
37 >
38 > There are a couple of cosmetic changes I'm considering as well (such as
39 > how --chroot flag is parsed).
40 >
41 > -- Peter Levine
42
43 Sorry, wrong patch.
44
45 I've attached the correct one.
46
47 -- Peter Levine

Attachments

File name MIME type
shadow-4.1.4.2-chroot.patch text/x-patch