From c3ce10e49c44ae2bef540a169d4cf718b1554d0c Mon Sep 17 00:00:00 2001 From: Jan Tattermusch Date: Wed, 14 Apr 2021 14:00:57 +0200 Subject: [PATCH] use multiarch/qemu-user-static docker image for registering qemu --- .../aarch64/qemu_helpers/prepare_qemu.sh | 24 ++++++++----------- 1 file changed, 10 insertions(+), 14 deletions(-) diff --git a/kokoro/linux/aarch64/qemu_helpers/prepare_qemu.sh b/kokoro/linux/aarch64/qemu_helpers/prepare_qemu.sh index aa78e994cd..f61320222a 100755 --- a/kokoro/linux/aarch64/qemu_helpers/prepare_qemu.sh +++ b/kokoro/linux/aarch64/qemu_helpers/prepare_qemu.sh @@ -10,21 +10,17 @@ 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 "F" flag we need (see below) -# To avoid the "unsupported syscall" warnings, we download a recent version of qemu-aarch64-static. -# On newer distributions (such as glinux), simply "apt install qemu-user-static" is sufficient. -curl -sSL --output qemu-aarch64-static https://github.com/multiarch/qemu-user-static/releases/download/v5.2.0-2/qemu-aarch64-static -chmod ugo+x qemu-aarch64-static -sudo mv qemu-aarch64-static /usr/local/bin -/usr/local/bin/qemu-aarch64-static --version - -# register qemu-aarch64-static with binfmt_misc to use it as emulator for aarch64 binaries (based on their magic and mask) -# The format of the configuration string is ":name:type:offset:magic:mask:interpreter:flags" -# The most important flag is "F", which allows the qemu-aarch64-static binary to be loaded regardless of chroot and namespaces. +# * 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 -# to be accessible from the docker image we're emulating. -echo -1 | sudo tee /proc/sys/fs/binfmt_misc/qemu-aarch64 # delete the existing registration -echo ":qemu-aarch64:M::\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/local/bin/qemu-aarch64-static:OCF" | sudo tee /proc/sys/fs/binfmt_misc/register +# 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