or, Adventures in Regressions and Crazy Ideas
This work is now done.
The rest of this page is kept only for reference and historical purposes.
Two Problems
opkg-lede and the Outsourced Inflation
opkg-lede now relies on an external gzip executable.
When upgrading a package, it tries to execute gzip to unpack maintainer
scripts and data files after removing the old version of the
package. When the package being upgraded is busybox, which provides gzip,
opkg crashes and leaves behind a completely broken system.
To reiterate, opkg-lede is (and has been for as long as it has been in
ProteanOS) currently unable to upgrade busybox, due to its own design.
The Amazing Alternatives of busybox
Instead of adding alternatives one at a time, it would be
nice to manage all of busybox's utility links using
update-alternatives. Unfortunately, the maintainer script that runs
update-alternatives (as well as the update-alternatives script
itself) needs a few busybox utilities (/bin/sh for a start). Thus, after an
older version of busybox is deconfigured, a newer version can't be configured.
busybox also can't be configured when first unpacked by prokit.
One Solution
The next version of src:opkg-lede (likely 0+git20190131.d4ba162-7) already
will have a wrapper script called opkg that executes opkg-cl (the
actual binary executable). The script can be extended to first save a copy of
/bin/busybox to an empty temporary directory, generate utility links to it in
the directory, and add the directory to PATH. Until all of this setup is
complete, the wrapper script must be careful to execute utilities as busybox
$util (a full path to busybox won't be necessary, as the usual /bin/busybox
will be available at that point). This includes the interpreter line, which
will need to be changed to #!/bin/busybox sh. ash built-in utilities can be
used as usual.
The busybox package can't use update-alternatives to manage all of its
utility links until an opkg-lede with this wrapper script functionality is
uploaded. This is because, even if busybox's postinst script is modified to
use the busybox executable directly, other packages' maintainer scripts may be
executed first, while busybox is unpacked but not yet configured (and
therefore utility links are not yet created).
Once this new opkg-lede package is uploaded and busybox uses
update-alternatives for everything, busybox would need to declare that it
Breaks older versions of opkg-lede, to ensure that opkg-lede will preserve
a copy of the busybox executable and its utility links. However, this is
still insufficient, as the version of opkg that is running must have already
set up this environment before busybox is upgraded. busybox's prerm
script will need to check for this somehow and abort the upgrade if opkg is
too old to have prepared for a safe upgrade. One solution is for the opkg
script to set an OPKG_BUSYBOX_SAVED environment variable.
The opkg script of the opkg-lede package will need to read busybox's list
of alternatives links. This is currently located at
/usr/share/busybox/alternatives. The file's format will change when
busybox uses update-alternatives for everything: the last two columns (name
and priority) will be dropped. opkg however can simply read the first column,
so it will maintain compatibility.