| #!/bin/bash |
| # |
| # Setup and configure qemu userspace emulator on kokoro worker so that we can seamlessly emulate processes running |
| # inside docker containers. |
| |
| set -ex |
| |
| # show pre-existing qemu registration |
| cat /proc/sys/fs/binfmt_misc/qemu-aarch64 |
| |
| # Kokoro ubuntu1604 workers have already qemu-user and qemu-user-static packages installed, but it's and old version that: |
| # * prints warning about some syscalls (e.g "qemu: Unsupported syscall: 278") |
| # * doesn't register with binfmt_misc with the persistent ("F") flag we need (see below) |
| # |
| # To overcome the above limitations, we use the https://github.com/multiarch/qemu-user-static |
| # docker image to provide a new enough version of qemu-user-static and register it with |
| # the desired binfmt_misc flags. The most important flag we need is "F" (set by "--persistent yes"), |
| # which allows the qemu-aarch64-static binary to be loaded eagerly at the time of registration with binfmt_misc. |
| # That way, we can emulate aarch64 binaries running inside docker containers transparently, without needing the emulator |
| # binary to be accessible from the docker image we're emulating. |
| # Note that on newer distributions (such as glinux), simply "apt install qemu-user-static" is sufficient |
| # to install qemu-user-static with the right flags. |
| docker run --rm --privileged multiarch/qemu-user-static:5.2.0-2 --reset --credential yes --persistent yes |
| |
| # Print current qemu reqistration to make sure everything is setup correctly. |
| cat /proc/sys/fs/binfmt_misc/qemu-aarch64 |
