Embedded package managers sucks

2009-07-02T14:08:00+02:00

Years ago someone wrote IPKG in pure shell. It can be still found in some distributions. Then it was rewritten into C and this version we used in OpenEmbedded derived systems. It had some bugs, we patched some of them, from time to time there was even upstream development done for it.

Then Openmoko arrived and forked IPKG — new project got OPKG name. It was written by OpenedHand and Openmoko developers. Their main goals were:

callbacks for GUI package managers
GPG signed repositories
fixing bugs

Many things got changed, OE patches got merged, new bugs was added. Those who use CLI version of opkg (so far the only usable client) lost some functionalities — for example there is no progress bar when packages are fetched.

For last few months OPKG is in unmaintained mode again and I think that this is some kind of curse on embedded market package managers.

Some time ago I discovered that when many (>50) packages needs to be upgraded then opkg segfaults during process and this is not a matter of going out of RAM as I have ~400MB free. Today it did not gave value of PATH for post install scripts… I wonder what else can be found ;(

What are other options? So far I know two — dpkg + apt or rpm + yum. First one costs few megabytes of space, second one require also Python so it is not acceptable for most of our targets. Both also require rebuilding of everything :(

How to install additional software into your OE generated rootfs

2009-01-22T19:18:00+01:00

There are few methods of adding software into rootfs. You can copy binaries but you can also go better way by using packages. I know that this can be strange experience for some people (which are used to systems which generates only binaries) but in OpenEmbedded world effect of software build is set of packages which can be used to generate final rootfs image.

First thing to check is which package contains needed binary. It is easier if package name has binary name (like ‘alsa-utils-aplay’ which contains ‘aplay’ command) but it is not always so easy. Hopefully OpenEmbedded generates ‘Packages.filelist’ file in ‘tmp/deploy/glibc/ipk/’ subdirectories. If they are empty (common situation) they need to be recreated.

To generate them user needs to remove ‘Packages*’ files from all directories and call bitbake package-index command. When command finishes ‘Packages.filelist’ files should contain all informations — for example ‘update-inetd’ command line looks like this

update-inetd netbase:armv6:./usr/sbin/update-inetd

The format is simple:

BINARY-NAME PACKAGE:ARCH:PATH-TO-BINARY

So when package name is known we need to transfer package into device. This part depends on device so I will not elaborate on it.

Installing package is simple: opkg install package.ipk. But copying single packages can result in frustration called ‘dependency hell’ (package require another package which require another etc). To check which packages will be required the easiest way is dpkg-deb -I package.ipk (as IPK packages are compatible with DEBs).

Better way is to use repositories of packages — command simplify to opkg update;opkg install package (users of desktop Linux distributions can compare it with apt-get or yum). If you built Ångström distribution then your rootfs already contains all informations needed to use packages from repositories. For other distros user needs to define them by hand.

Repository informations are stored in ‘/etc/opkg/*-feed.conf’ files. Format is simple:

src/gz NAME URL

Example:

src/gz base http://www.angstrom-distribution.org/feeds/2008/ipk/glibc/armv5te/base

Instead of ‘src/gz’ also ‘src’ can be used — it will fetch uncompressed ‘Packages’ file instead of gzipped one.

When repositories are defined installing software is easy: opkg update;opkg install package will fetch package and all it’s dependencies and then will install them into rootfs.

I hope that this will simplify that task for some people.

Marcin Juszkiewicz - packages

Embedded package managers sucks

How to install additional software into your OE generated rootfs