Re: [gentoo-embedded] emerge --root : users not created

[P. Levine]

Peter Stuge wrote:
> I talked to upstream on freenode/#shadow and they welcome a patch for
> adding --chroot
>
> chroot() needs to happen really early since useradd and friends read
> some configuration files to know e.g. which password encryption
> method to use.

Attached is a tentative patch to add a chroot flag to useradd and
groupadd (via --chroot or -R).  It compiles and works on my end
(--chroot /usr/armv4tl-softfloat-linux-gnueabi) with various other flags
enabled.  I'm hoping for others to test it and get some feedback before
I submit it to shadow upstream.

There do exist a couple of issues:

sysconf(_SC_NGROUPS_MAX) is called by useradd early on.  This would
report the maximum allowable number of groups per user on the build
system, not the target.  To my knowledge, this is set by the kernel and
would have to be used.  However, this tends to be a very high number for
linux kernel >= 2.6.3 (65536) so it seems like a mute point (for linux
kernel >= 2.6.3).

There are a number of calls to "getXXbyYY" functions (i.e., getgrgid,
getpwnam, etc...).  These seem to be dynamically preloaded and access
preloaded databases.  They are unaffected by chroot() (even after
setting __nss_configure_lookup(foo, files)).  I've instead used shadow's
own method of macro expansion to generate functions doing the
equivalent, with recursive calls to fgetXXent functions.

And PAM functionality doesn't work and has to be disabled while using
chroot().  I don't know very much about PAM.  Would this be a problem?

Also,  the chroot functionality could probably be easily extended to
other modules but I'm not sure if this would be acceptable upstream.

There are a couple of cosmetic changes I'm considering as well (such as
how --chroot flag is parsed).

-- Peter Levine