Running glibc programs
 Do not follow instructions here until this notice is removed. |
If you want to run glibc programs in Alpine Linux, there are a few ways of doing so. You could install glibc as additional to uclibc (you would have to do this manually), or you could do it the easy way and use a chroot.
Because there are different use cases, this is just a slight overview about what's possible and what's intelligent.
Your options
Using BusyBox
First, the most simple approach for setting up a chroot is by using a glibc build of BusyBox.
This approach has just a few downsides:-
- You have to link most
/bin/and/usr/binprograms against/bin/busybox, and some BusyBox builds break if you don't configure them correctly. - You have to manually download every library you need for your program manually.
However, if you want a small environment for one simple use case, then this is the solution you want.
Using a live CD
If you prefer using any special distro, you can always download and extract a live CD and use it as a chroot enviroment.
Using an image
For Gentoo, it is the slowest approach especially on slow machines since it is not binary distribution and can be indecisive, but you have the advantage of controlling the package version of whichever library you will install. A drawback would be a big build. You have to install a Portage tree, which uses up a lot of space. (It's not 100% necessary if you don't have to install any additional content that you won't need.) Sometimes the package will fail on compilation phase of emerge. You either end up patching it yourself or waiting for a fix to appear on their Bugzilla from an experienced user.
For Arch or Debian, it is recommended since packages are precompiled and better at unattended package installation. This approach isn't as easily executed as the other alternatives, but this may be the cleanest and most recommended one for the every day user.
How to do it
This is just a quick draft, so here it comes.
Using BusyBox
First, we need to download BusyBox. You can choose any of your favourite distros to download a prebuilt version. For instance, you could use Arch Linux packages, as follows:
wget http://www.archlinux.org/packages/community/i686/busybox/download/ -O busybox.pkg.tar.xz wget http://www.archlinux.org/packages/core/i686/glibc/download/ -O glibc.pkg.tar.xz mkdir -p ~/chroot/usr/bin/ ~/chroot/{dev,proc,root,etc} for i in *.pkg.tar.xz;do bsdtar xfJ $i -C ~/chroot done cp /etc/resolv.conf ~/chroot/etc/ ln -s /bin/busybox ~/chroot/bin/sh ln -s /bin/busybox ~/chroot/bin/ln sudo chroot ~/chroot/ /bin/sh
This creates a simple chroot enviroment, which we will expand through all the commands included in BusyBox:
for i in $(busybox --list);do ln -s /bin/busybox /usr/bin/$i;done
Using a live CD
Contributions welcome |
Using an image
Gentoo Linux
Select a stage3 from here and portage latest from here at gentoo/snapshots/portage-latest.tar.xz.
First,
sudo apk add xz
You also may need the vanilla kernel. If any time Gentoo decides to update PAM, you need it for it to emerge successfully without problems.
sudo apk add kernel-vanilla
Add the kernel-vanilla to Grub and reboot with the vanilla kernel if you are going to pull in both git and layman which they use to download user community supported packages.
Enter the chroot:
mkdir ~/chroot cd ~/chroot tar -xvf stage3-*.tar.xz tar -xvf portage-latest.tar.xz mv portage usr sudo mount --bind /dev dev sudo mount --bind /sys sys sudo mount -t proc proc proc cp /etc/resolv.conf etc sudo chroot . /bin/bash
And voilà, you have your working Gentoo chroot!
You can now take a look at Gentoo's Handbook to find out how you can configure and install your system, or simply extract/copy the program you need to run in your chroot enviroment and execute it.
Here is a wrapper script that is similar to arch-chroot when you frequently reuse this chroot:
Contents of gentoo-chroot.sh
Do at chmod +x gentoo-chroot.sh to get it to work.
Arch Linux
Although pacstrap is included with the arch-install-scripts package, it will not work unless the target directory is a mountpoint, so the Arch bootstrap image must be used instead (the image is updated every month, so change the date in the link as required):
sudo apk add arch-install-scripts mkdir ~/chroot && cd ~/chroot curl -O https://mirrors.kernel.org/archlinux/iso/latest/archlinux-bootstrap-2018.01.01-x86_64.tar.gz tar xzf archlinux-bootstrap-2018.01.01-x86_64.tar.gz && rm archlinux-bootstrap-2018.01.01-x86_64.tar.gz sed -i '/evowise/s/^#//' root.x86_64/etc/pacman.d/mirrorlist sudo arch-chroot root.x86_64 [chroot]# pacman-key --init [chroot]# pacman-key --populate archlinux
Once that is done, update the system and install the desired package(s) (denoted by "foo" in this example):
[chroot]# pacman -Syu foo
Debian
Use the provided debootstrap package to create the Debian chroot. --arch is optional, depending of your needs.
On the linux-grsec kernel, you will need to relax chroot limitations:
sudo apk add debootstrap for i in /proc/sys/kernel/grsecurity/chroot_*; do echo 0 | sudo tee $i; done mkdir ~/chroot sudo debootstrap --arch=i386 wheezy ~/chroot http://http.debian.net/debian/ for i in /proc/sys/kernel/grsecurity/chroot_*; do echo 1 | sudo tee $i; done sudo chroot ~/chroot /bin/bash
You can now use apt-get to install needed packages.
Examples
Source dedicated server
Here is an easy example of how you can run srcds in a simple BusyBox chroot.
For this server, you will only need the basic chroot and an advanced tar version (the BusyBox version is not sufficient because of the missing -U command):
wget http://www.archlinux.org/packages/community/i686/busybox/download/ -O busybox.pkg.tar.xz wget http://www.archlinux.org/packages/core/i686/glibc/download/ -O glibc.pkg.tar.xz wget http://www.archlinux.org/packages/core/i686/tar/download/ -O tar.pkg.tar.xz mkdir -p ~/chroot/usr/bin/ ~/chroot/{dev,proc,root,etc} for i in *.pkg.tar.xz;do bsdtar xfJ $i -C ~/chroot done cp /etc/resolv.conf ~/chroot/etc/ ln -s /bin/busybox ~/chroot/bin/sh ln -s /bin/busybox ~/chroot/bin/ln sudo chroot ~/chroot/ /bin/sh
Now that you are in a working chroot, you can download the server and install it. You just have to execute the following self-explaining commands...
mkdir ~/work cd ~/work busybox wget http://www.steampowered.com/download/hldsupdatetool.bin chmod +x hldsupdatetool.bin ln -s /bin/busybox ./uncompress cp /bin/tar . #right now executing programs from $PATH is buggy, soon to be fixed (no bug in BusyBox, but in my script) ./hdsupdatetool.bin #you can accept it or not ;) ./steam ./steam
...and you should have a working chroot with srcds installed in it.
If you think you are clever or elegant, you can use the server with a bash script:
#!/bin/bash chroot ~/chroot /root/work/steam $@
Just save it (in your Alpine installation) under /usr/bin/steam, do a chmod +x /usr/bin/steam and have fun!
MegaCli
So let's run MegaCli in a chroot too, shall we? ;)
First we set up a uclibc chroot :)
MegaCli needs more than just glibc. It needs ncurses and the gcc-libs:
wget http://www.archlinux.org/packages/community/i686/busybox/download/ -O busybox.pkg.tar.xz wget http://www.archlinux.org/packages/core/i686/glibc/download/ -O glibc.pkg.tar.xz wget http://www.archlinux.org/packages/core/i686/ncurses/download/ -O ncurses.pkg.tar.xz wget http://www.archlinux.org/packages/core/i686/gcc-libs/download/ -O gcc-libs.pkg.tar.xz mkdir -p ~/chroot/usr/bin/ ~/chroot/{dev,proc,root,etc,sys} cp /etc/resolv.conf ~/chroot/etc/ for i in *.pkg.tar.xz;do bsdtar xfJ $i -C ~/chroot done ln -s /bin/busybox ~/chroot/bin/sh ln -s /bin/busybox ~/chroot/bin/ln
After this, we visit this site and download 8.02.16_MegaCLI.zip.
mkdir tmp cd tmp unzip ../8.02.16_MegaCLI.zip cd LINUX unzip MegaCliLin.zip #Now comes code stolen from rpm2cpio o=`expr 96 + 8` set `od -j $o -N 8 -t u1 MegaCli-8.02.16-1.i386.rpm` il=`expr 256 \* \( 256 \* \( 256 \* $2 + $3 \) + $4 \) + $5` dl=`expr 256 \* \( 256 \* \( 256 \* $6 + $7 \) + $8 \) + $9` sigsize=`expr 8 + 16 \* $il + $dl` o=`expr $o + $sigsize + \( 8 - \( $sigsize \% 8 \) \) \% 8 + 8` set `od -j $o -N 8 -t u1 MegaCli-8.02.16-1.i386.rpm` il=`expr 256 \* \( 256 \* \( 256 \* $2 + $3 \) + $4 \) + $5` dl=`expr 256 \* \( 256 \* \( 256 \* $6 + $7 \) + $8 \) + $9` hdrsize=`expr 8 + 16 \* $il + $dl` o=`expr $o + $hdrsize` dd if=MegaCli-8.02.16-1.i386.rpm ibs=$o skip=1 2>/dev/null |bsdtar -xf - #wow ... rm opt/MegaRAID/MegaCli/MegaCli64 # who needs 64bit? cp -r opt/ ~/chroot/
Now we have a working MegaCli client in our chroot.
As with srcds, we do not want to operate from inside the chroot, so here is a little script that should ease you up (use at your own risk):
#!/bin/bash user=$(whoami) if [ "$user" != "root" ];then echo "This script needs root access" exit fi mount -t proc proc ~/chroot/proc/ mount --bind /dev/ ~/chroot/dev/ mount --bind /sys/ ~/chroot/sys/ #we may need dev and maybe proc too to use this program chroot ~/chroot /opt/MegaRAID/MegaCli/MegaCli $@ umount ~/chroot/proc umount ~/chroot/dev umount ~/chroot/sys
Save it under /usr/bin/MegaCli. Do a chmod +x /usr/bin/MegaCli and good luck.
Note: This method takes around 50mb. If you need something smaller, then you can strip a few files from glibc (not recommended), or work on a squashfs.
With the following, you can create a squashfs that is around 15mb small:
mksquashfs ~/chroot/ /chroot.sfs -b 65536
When you add a unionfs layer, you can even use it with write access, or you can bind some directories to the writeable directories before you chroot into it.
I will look into it later on.
You can save the chroot in another directory than your home directory, and you can even install a chroot through an APKBUILD (after someone wrote it).
With this, you could use many glibc-dependent programs through one chroot, but be aware that running programs like this should not be standard. This should only be used in extreme situations, as in _closed source_ tools linked against glibc.
Skype on Debian chroot
Not yet validated |
This is an example on how to run Skype from a Debian 32b chroot.
sudo chroot ~/chroot wget http://www.skype.com/go/getskype-linux-deb dpkg -i getskype-linux-deb
To fix missing dependencies, you will want to use:
apt-get -f install
Then, exit the chroot:
exit
Fix PAX flags on Skype binary - linux-grsec only.
ELF marking with paxctl cannot be used because Skype binary refuses to run if modified.
CONFIG_PAX_XATTR_PAX_FLAGS is NOT yet available in linux-grsec.
sudo apk add attr sudo setfattr -n user.pax.flags -v "em" ~/chroot/usr/bin/skype
Mount needed directories in the chroot read-only to limit access to the system devices.
Give write access to /dev/v4l and to /dev/snd in order to let Skype use the webcam device: Skype is not compatible with Alsa anymore and requires Pulseaudio to be running.
sudo mount -o bind /proc ~/chroot/proc sudo mount -o bind,ro,remount /proc ~/chroot/proc sudo mount -o bind /sys ~/chroot/sys sudo mount -o bind,ro,remount /sys ~/chroot/sys sudo mount -o bind /dev ~/chroot/dev sudo mount -o bind,ro,remount /dev ~/chroot/dev sudo mount -o bind /dev/v4l ~/chroot/dev/v4l sudo mount -t tmpfs -o nodev,nosuid,noexec shm $CHROOT_PATH/dev/shm
Enter the chroot and create a user:
sudo chroot ~/chroot useradd -G audio,video <username> exit
Then run Skype as your newly created user:
sudo chroot ~/chroot /bin/su - <username> -c /usr/bin/skype
Dungeon Crawl (Stone Soup) on Arch
Once the Arch system is laid down (to ~/chroot/root.x86_64 in this example), install the game:
sudo arch-chroot ~/chroot/root.x86_64 [chroot]# pacman -Syu crawl-tiles
Then exit the chroot and run it with this command:
sudo arch-chroot ~/chroot/root.x86_64 /bin/su -c 'DISPLAY=:0 crawl-tiles'
A separate user can also be created to run the game, if preferred.
Spotify
Docker method
Read the Docker page to install it. Then clone the repository, as shown below. It will automate the process of pulling all the dependencies, and PaX marks it for the hardened kernel. The advantage of this container is that it is ready-to-use and has stripped down many of the /usr/bin executables. The downside is that is unstable.
git clone https://github.com/orsonteodoro/docker-arch-spotify-PaXmarked
Follow the instructions in the README.md
Chroot method
The Chroot method the preferred method; it doesn't have the black screen bug and is more stable. Just translate the Dockerfile instructions into native sh (Bourne shell). The trick again is to run Spotify as root with sudo inside the chroot – not as regular user.
Use sudo aplay -l to verify that the soundcard is detected. When you use either this or the Docker method, which relies on ALSA, there could be a conflict depending on who grabs the sound card. Stop all browsers or programs using the sound device outside of the chroot or the docker image so that Spotify can use it.
I did some translation. You may need to make changes.
To update, just delete it and call alpine-spotify-installer.sh again. You will still need the Arch Linux bootstrap image. Extract the image. Next, copy and paste the code shown below into root.x86_64; chmod +x alpine-spotify-installer.sh. Then, run sudo arch-chroot root.x86_64. Then, run ./alpine-spotify-installer.sh.
Contents of alpine-spotify-installer.sh
To make this easier, create a launcher script:
Contents of run.sh
You may want to look at this script to learn how to lock it down by removing the unnecessary cruft in your chroot collections that may be abused.