opkg/rpm inconsistencies in multilib image installations

["Peter A. Bigot" <pab@pabigot.com>]

tl;dr: multilib apparently defines its own root directory underneath 
${IMAGE_ROOT} which includes copies of /etc files like passwd that are 
not known to pseudo.  opkg and rpm differ in whether useradd scripts are 
run when a multilib package is installed, resulting in failures to add 
users/groups during multilib install when using opkg because a sanity 
check thinks they already exist because pseudo is looking somewhere else.

Details:

Ross pointed out in 
http://lists.openembedded.org/pipermail/openembedded-core/2014-November/099032.html 
that the patches to prevent using host /etc files in pseudo failed under 
multilib and asked me to look into it.

Recall that with these patches PSEUDO_PASSWD (where pseudo looks up 
users and groups for getpwnam(3) etc) is set in bitbake.conf to:

PSEUDO_PASSWD ?= "${STAGING_DIR_TARGET}:${STAGING_DIR_NATIVE}"

where STAGING_DIR_NATIVE holds the fallback files that provide only 
enough entries to get fs-perms.txt to work before the target staging 
/etc exists.

Because images are different and with some packagers base-passwd can't 
be installed unless user root can be resolved, in an (updated) 
image.bbclass we use this:

# Prefer image, but use the fallback files for lookups if the image ones
# aren't yet available.
PSEUDO_PASSWD = "${IMAGE_ROOTFS}:${STAGING_DIR_NATIVE}"

Adding this line to perform_groupadd in useradd_base.bbclass
        bbnote "rootdir $rootdir 
PSEUDO_PASSWD=${PSEUDO_PASSWD}=$PSEUDO_PASSWD"

and adding linebreaks for readability, I'm finding that when 
lib32-dbus-1 is installed with PACKAGE_CLASSES = "package_ipk" we have:

rootdir
  /prj/oe/omap/build-ab-multilib/tmp/work/qemux86_64-poky-linux/core-image-sato/1.0-r0/multilib/lib32
PSEUDO_PASSWD
=/prj/oe/omap/build-ab-multilib/tmp/sysroots/lib32-qemux86-64
:/prj/oe/omap/build-ab-multilib/tmp/sysroots/x86_64-linux
=/prj/oe/omap/build-ab-multilib/tmp/work/qemux86_64-poky-linux/core-image-sato/1.0-r0/rootfs
:/prj/oe/omap/build-ab-multilib/tmp/sysroots/x86_64-linux

In other words, useradd.bbclass (1) thinks the etc directory is in $D, 
the bitbake variable PSEUDO_PASSWD during build (2) thinks it's in the 
multilib 32-bit target staging directory, and the PSEUDO_PASSWD actually 
running (3) thinks it's in IMAGE_ROOT.

Because of this, useradd.bbclass can't find netdev in $D/etc/group so 
invokes groupadd which does a sanity check and complains that netdev 
already exists in ${IMAGE_ROOT}/etc/group and things crumble to a stop.

Interestingly the build+install works with PACKAGE_CLASSES = 
"package_rpm" which shows this for the install of 
dbus-1-1.8.2-r0.3.core2_64.rpm:

rootdir
  /prj/oe/omap/build-ab-multilib/tmp/work/qemux86_64-poky-linux/core-image-sato/1.0-r0/rootfs
PSEUDO_PASSWD
=/prj/oe/omap/build-ab-multilib/tmp/sysroots/qemux86-64
:/prj/oe/omap/build-ab-multilib/tmp/sysroots/x86_64-linux
=/prj/oe/omap/build-ab-multilib/tmp/work/qemux86_64-poky-linux/core-image-sato/1.0-r0/rootfs
:/prj/oe/omap/build-ab-multilib/tmp/sysroots/x86_64-linux

and either does not install dbus-1-1.8.2-r0.3.lib32_x86.rpm or somehow 
prevents the groupadd scripts from being run.

Whatever's going on here, RPM and OPKG appear to differ in the 
environment and selected packages for multilib images, which surely 
isn't right. I didn't check deb.

Once somebody reconciles the packager behaviors, I'll return to deal 
with any remaining changes to pseudo.  If we have to allow multilib to 
create users/groups in a non-standard root directory it's gonna get messy.

Peter