base-passwd/useradd: Various improvements to useradd with RSS

Currently there are multiple issues with useradd:

* If base-passwd rebuilds, it wipes out recipe specific user/group additions
  to sysroots and causes errors
* If recipe A adds a user and recipe B depends on A, it can't see any of the
  users/groups A adds.

This patch changes base-passwd so it always works as a postinst script
within the sysroot and copies in the master files, then runs any
postinst-useradd-* scripts afterwards to add additional user/groups.

The postinst-useradd-* scripts are tweaked so that if /etc/passwd doesn't exist
they just exit, knowning they'll be executed later. We also add a dummy entry to
the dummy passwd file from pseudo so we can avoid this too.

There is a problem where if recipe A adds a user and recipe B depends on A but
doesn't care about users, it may not have a dependency on the useradd/groupadd
tools which would therefore not be available in B's sysroot. We therefore also
tweak postinst-useradd-* scripts so that if the tools aren't present we simply
don't add users. If you need the users, you add a dependency on the tools in the
recipe and they'll be added.

We add postinst-* to SSTATE_SCAN_FILES since almost any postinst script of this
kind is going to need relocation help.

We also ensure that the postinst-useradd script is written into the sstate
object as the current script was only being added in a recipe local way.

Thanks to Peter Kjellerstedt <pkj@axis.com> and Patrick Ohly for some pieces
of this patch.

[Yocto #11124]

(From OE-Core rev: 1b5afaf437f7a1107d4edca8eeb668b9618a5488)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/meta/recipes-devtools/pseudo/files/fallback-passwd b/meta/recipes-devtools/pseudo/files/fallback-passwd
index 0889c5704c..08611baaf4 100644
--- a/meta/recipes-devtools/pseudo/files/fallback-passwd
+++ b/meta/recipes-devtools/pseudo/files/fallback-passwd
@@ -1,2 +1,3 @@
 root::0:0:root:/home/root:/bin/sh
+pseudopasswd:*:1:1:this-is-the-pseudo-passwd:/nonexistent:/bin/sh
 nobody:*:65534:65534:nobody:/nonexistent:/bin/sh